| 1. |
- Chiappa, Giulia, et al.
(författare)
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A Novel High Discriminatory Protocol for the Detection of Borrelia afzelii, Borrelia burgdorferi Sensu Stricto and Borrelia garinii in Ticks
- 2022
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Ingår i: Pathogens. - : MDPI. - 2076-0817. ; 11:11
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Tidskriftsartikel (refereegranskat)abstract
- Bacteria of the Borrelia burgdorferi sensu lato complex are the causative agents of Lyme borreliosis (LB). Even if the conventional diagnosis of LB does not rely on the species itself, an accurate species identification within the complex will provide a deepened epidemiological scenario, a better diagnosis leading to a more targeted therapeutic approach, as well as promote the general publics awareness. A comparative genomics approach based on the 210 Borrelia spp. genomes available in 2019 were used to set up three species-specific PCR protocols, able to detect and provide species typing of Borrelia afzelii, Borrelia burgdorferi sensu stricto (s.s.) and Borrelia garinii, the three most common and important human pathogenic Lyme Borrelia species in Europe. The species-specificity of these protocols was confirmed on previously identified B. afzelii, B. burgdorferi s.s. and B. garinii specimens detected in Ixodes ricinus samples. In addition, the protocols were validated on 120 DNA samples from ticks collected in Sweden, showing 88% accuracy, 100% precision, 72% sensitivity and 100% specificity. The proposed approach represents an innovative tool in epidemiological studies focused on B. burgdorferi s.l. occurrence in ticks, and future studies could suggest its helpfulness in routine diagnostic tests for health care.
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| 2. |
- Dwibedi, Chinmay Kumar, et al.
(författare)
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Biological amplification of low frequency mutations unravels laboratory culture history of the bio-threat agent Francisella tularensis
- 2020
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Ingår i: Forensic Science International. - : Elsevier. - 1872-4973 .- 1878-0326. ; 45
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Tidskriftsartikel (refereegranskat)abstract
- Challenges of investigating a suspected bio attack include establishing if microorganisms have been cultured to produce attack material and to identify their source. Addressing both issues, we have investigated genetic variations that emerge during laboratory culturing of the bacterial pathogen Francisella tularensis. Key aims were to identify genetic variations that are characteristic of laboratory culturing and explore the possibility of using biological amplification to identify genetic variation present at exceedingly low frequencies in a source sample. We used parallel serial passage experiments and high-throughput sequencing of F. tularensis to explore the genetic variation. We found that during early laboratory culture passages of F. tularensis, gene duplications emerged in the pathogen genome followed by single-nucleotide polymorphisms in genes for bacterial capsule synthesis. Based on a biological enrichment scheme and the use of high-throughput sequencing, we identified genetic variation that likely pre-existed in a source sample. The results support that capsule synthesis gene mutations are common during laboratory culture, and that a biological amplification strategy is useful for linking a F. tularensis sample to a specific laboratory variant among many highly similar variants.
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| 3. |
- Engström, Elisabet, et al.
(författare)
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Auditory event-related potentials and mismatch negativity in children with hearing loss using hearing aids or cochlear implants : A three-year follow-up study
- 2021
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Ingår i: International Journal of Pediatric Otorhinolaryngology. - : Elsevier. - 0165-5876 .- 1872-8464. ; 140
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The primary aim was to examine how event-related potentials (ERPs) and mismatch negativity (MMN) change and develop over time among children with hearing loss (HL) using hearing aids (HAs) or cochlear implants (CIs). Children with normal hearing (NH) were tested as a reference group.Methods: This three-year follow-up study included 13 children with sensorineural HL (SNHL); 7 children using bilateral HAs and 6 children using CIs; and 10 children with NH as a reference group. ERPs were recorded at baseline and after three years. At time for the original study the children were approximately 5-8 years old and at the follow-up study 8-11 years old. ERP recordings and data processing were identical in both sessions. A standard stimulus alternated with five different deviants (gap, intensity, pitch, location and duration), presented in a pseudorandom sequence, thus following the multi-feature paradigm, Optimum-1. MMN was calculated from the average ERP of each deviant minus the standard stimuli. Repeated measures ANOVA was used for the statistical analyses and the results were based on samples within a specific time interval; 80-224 ms.Results: There was a statistically significant difference in the obligatory responses between the NH and HA groups at baseline, but this difference disappeared after three years in our follow-up study. The children with HA also showed a significant difference in mean ERP at baseline compared to follow-up, and significant differences between the deviants at follow-up but not at baseline. This suggests an improvement over time among the children with HAs. On the other hand, the children with CIs did not differ from the NH children at baseline, but after three years their mean ERP was significantly lower compared to both the children with HA and NH, indicating a reduced development of the central auditory system in this age span among the children with CIs. Regarding MMN, there was an interaction between the duration deviant and time for the children with HA, also indicating a possible improvement over time among the HA children.Conclusions: This three-year follow-up study shows neurophysiological differences between children with HL and children with NH. The results suggest a delay in the central auditory processing among the HA children compared to children with NH, but a possible catch-up, over time, and this potential may be worth to be utilized. Regarding the CI children, similar improvement in this age span is missing, meaning there are differences between the subgroups of children with HL, i.e. the children with HAs vs. CIs. The results highlight the importance of distinguishing between subgroups of children with HL in further research.
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| 4. |
- Engström, Elisabet, et al.
(författare)
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Computer-assisted reading intervention for children with hearing impairment using cochlear implants : Effects on auditory event-related potentials and mismatch negativity
- 2020
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Ingår i: International Journal of Pediatric Otorhinolaryngology. - : Elsevier. - 0165-5876 .- 1872-8464. ; 137
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The primary aim was to find out whether a computer-assisted reading intervention program with a phonic approach can affect event-related (ERPs) and mismatch negativity (MMN) in hearing impaired (HI) children using cochlear implants (CIs).METHODS: This study involved a test group of 15 HI children with CIs and a control group of 14 normal hearing (NH) children. The children were 4 years and 10 months to 8 years and 1 month old. ERPs were recorded immediately before and after 4 weeks of training with a computer-assisted reading intervention, GraphoGame. A multi-feature paradigm, Optimum-1, was used, i.e. a standard stimulus alternated with five different deviants: gap intensity, pitch, location and duration. MMN was calculated from the mean amplitude ERP of each deviant minus the standard stimulus response in a specific time interval, 80 - 224 ms. Repeated measures ANOVA was used for the statistical analysis.RESULTS: The results did not show any significant changes with the computerassisted training in the ERPs and MMNs among the HI children with CIs. The presence of both MMN and a positive mismatch response (pMMR), which might reflect an immaturity, complicates interpreting the results in this age group. Individually, there was a mix of MMNs and pMMRs among all participants, pre and post training, and the change of each deviant after intervention was not predictable.CONCLUSIONS: There are no significant changes in ERP or MMN after intervention, however lack of significances must be interpreted with caution. Besides the presence of both MMNs and pMMRs, only modest changes are to be expected on an individual basis and small samples hinder making statistical conclusions regarding the training's effects. The study contributes to some more descriptive pieces of ERPs and MMNs among the HI children with CIs. The issues of MMN and pMMR are highlighted.
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| 5. |
- Ericson, Petter, 1986-, et al.
(författare)
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Tracing class and capitalism in critical AI research
- 2024
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Ingår i: tripleC. - : TripleC. - 1726-670X. ; 22:1, s. 307-328
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Tidskriftsartikel (refereegranskat)abstract
- This article explores the rapidly developing field of Critical AI Studies and its relation to issues of class and capitalism through a hybrid approach based on distant reading of a newly collected corpus of 300 full-text scientific articles, the creation of which is itself a first attempt at properly delineating the field. We find that words related to issues of class are predominantly but not exclusively confined to a set of studies that make up their own distinct subfield of Critical AI Studies, in contrast to, e.g., issues of race and gender, which are more broadly present in the corpus.
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| 6. |
- Kjær, Lene Jung, et al.
(författare)
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Potential drivers of human tick-borne encephalitis in the Örebro region of Sweden, 2010-2021
- 2023
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Incidence of tick-borne encephalitis (TBE) has increased during the last years in Scandinavia, but the underlying mechanism is not understood. TBE human case data reported between 2010 and 2021 were aggregated into postal codes within Örebro County, south-central Sweden, along with tick abundance and environmental data to analyse spatial patterns and identify drivers of TBE. We identified a substantial and continuing increase of TBE incidence in Örebro County during the study period. Spatial cluster analyses showed significant hotspots (higher number of cases than expected) in the southern and northern parts of Örebro County, whereas a cold spot (lower number of cases than expected) was found in the central part comprising Örebro municipality. Generalised linear models showed that the risk of acquiring TBE increased by 12.5% and 72.3% for every percent increase in relative humidity and proportion of wetland forest, respectively, whereas the risk decreased by 52.8% for every degree Celsius increase in annual temperature range. However, models had relatively low goodness of fit (R2 < 0.27). Results suggest that TBE in Örebro County is spatially clustered, however variables used in this study, i.e., climatic variables, forest cover, water, tick abundance, sheep as indicator species, alone do not explain this pattern.
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| 7. |
- Kjellander, Pia, et al.
(författare)
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Validating a common tick survey method : cloth-dragging and line transects
- 2021
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Ingår i: Experimental & applied acarology. - : Springer Science and Business Media LLC. - 0168-8162 .- 1572-9702. ; 83:1, s. 131-146
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Tidskriftsartikel (refereegranskat)abstract
- Cloth-dragging is the most widely-used method for collecting and counting ticks, but there are few studies of its reliability. By using cloth-dragging, we applied a replicated line transects survey method, in two areas in Sweden with different Ixodes ricinus tick-densities (low at Grimso and high at Bogesund) to evaluate developmental stage specific repeatability, agreement and precision in estimates of tick abundance. 'Repeatability' was expressed as the Intraclass Correlation Coefficient (ICC), 'agreement' with the Total Deviation Index (TDI) and 'precision' by the coefficient of variation (CV) for a given dragging distance. Repeatability (ICC) and agreement (TDI) were higher for the most abundant instar (nymphs) and in the area of higher abundance. At Bogesund tick counts were higher than at Grimso and so also repeatability, with fair to substantial ICC estimates between 0.22 and 0.75, and TDI ranged between 1 and 44.5 counts of difference (thus high to moderate agreement). At Grimso, ICC was poor to moderate and ranged between 0 and 0.59, whereas TDI remained low with estimates lower or equal to 1 count (thus high agreement). Despite a 100-fold lower abundance at Grimso, the same level of precision for nymphs could be achieved with a 70% increase of dragging effort. We conclude that the cloth-dragging technique is useful for surveying ticks' and primarily to estimate abundance of the nymphal stage, whereas it rarely will be recommended for larvae and adults.
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| 8. |
- Kjellander, Petter, et al.
(författare)
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Winter activity of Ixodes ricinus in Sweden
- 2023
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Ingår i: Parasites & Vectors. - : BMC. - 1756-3305. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundIn Europe, Ixodes ricinus (Acari: Ixodidae) is the most widespread and abundant tick species, acting as a vector for several microorganisms of medical and veterinary importance. In Northern and Central Europe, the tick has a bimodal activity pattern consisting of a peak in spring to the beginning of summer and a second peak at the end of summer. However, several findings of ticks on animals during winter have been reported, which raises the question of whether this is an overwintering strategy or whether ticks are active during winter in Scandinavia. The objectives of our study were to determine (i) whether ticks were active and finding hosts during winter, (ii) whether they parasitize their hosts, and (iii) what climatic factors-i.e., temperature, snow depth and precipitation-govern tick winter activity.MethodsThroughout three winter seasons, we examined wild-living and free-ranging roe deer (Capreolus capreolus) for ticks on 332 occasions. In total, 140 individual roe deer were captured in two climatically contrasting sites in south-central Sweden, Grimso and the Bogesund research area, respectively. We re-examined individual roe deer up to 10 times within the same winter or approximately once a week (mean 10 days, median 7 days between re-examinations) and recorded the absence or presence of ticks on the animals, and tested to what extent meteorological factors affected tick activity. To determine the attachment day, we used the coxal/scutal index of 18 nymphs and 47 female ticks.ResultsIn total, 243 I. ricinus were collected from 301 roe deer captures between 14 December and 28 February at the Bogesund study site during three subsequent years (2013/2014-2015/2016). We found attached ticks every third to every second examination (32%, 48% and 32% of the examinations, respectively). However, we collected only three I. ricinus females from 31 roe deer captures at the Grimso study site between 17 December 2015 and 26 February 2016. At the Bogesund study site, based on 192 captures of previously examined deer, we collected 121 ticks, and ticks were found at 33%, 48% and 26% of the examinations during the respective winters. The probability of finding an attached tick on a roe deer at a temperature of -5 & DEG;C was > 8% & PLUSMN; 5 (SE), and that probability increased to almost 20% & PLUSMN; 7 (SE) if the air temperature increased to 5 & DEG;C.ConclusionsTo the best of our knowledge, this is the first time that winter-active nymphs and female ticks have been documented to attach and feed on roe deer during winter (December to February) in Scandinavia. The main weather conditions regulating winter activity for females were temperature and precipitation, and the lowest estimated air temperature for finding an active tick was well below 5 & DEG;C. The behaviour of winter-active and blood-feeding ticks was documented over several winters and in two contrasting areas, implying that it is a common phenomenon that should be investigated more thoroughly, since it may have important consequences for the epidemiology of tick-borne pathogens.
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| 9. |
- Minh, Nghia Nguyen Thi, et al.
(författare)
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Binding of a Pyrene-Based Fluorescent Amyloid Ligand to Transthyretin : A Combined Crystallographic and Molecular Dynamics Study
- 2023
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 127:30, s. 6628-6635
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Tidskriftsartikel (refereegranskat)abstract
- Misfolding and aggregation of transthyretin (TTR) causeseveralamyloid diseases. Besides being an amyloidogenic protein, TTR hasan affinity for bicyclic small-molecule ligands in its thyroxine (T4)binding site. One class of TTR ligands are trans-stilbenes. The trans-stilbenescaffold is also widely applied for amyloid fibril-specific ligandsused as fluorescence probes and as positron emission tomography tracersfor amyloid detection and diagnosis of amyloidosis. We have shownthat native tetrameric TTR binds to amyloid ligands based on the trans-stilbenescaffold providing a platform for the determination of high-resolutionstructures of these important molecules bound to protein. In thisstudy, we provide spectroscopic evidence of binding and X-ray crystallographicstructure data on tetrameric TTR complex with the fluorescent salicylicacid-based pyrene amyloid ligand (Py1SA), an analogue of the Congored analogue X-34. The ambiguous electron density from the X-ray diffraction,however, did not permit Py1SA placement with enough confidence likelydue to partial ligand occupancy. Instead, the preferred orientationof the Py1SA ligand in the binding pocket was determined by moleculardynamics and umbrella sampling approaches. We find a distinct preferencefor the binding modes with the salicylic acid group pointing intothe pocket and the pyrene moiety outward to the opening of the T4binding site. Our work provides insight into TTR binding mode preferencefor trans-stilbene salicylic acid derivatives as well as a frameworkfor determining structures of TTR-ligand complexes.
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| 10. |
- Nakeva von Mentzer, Cecilia, et al.
(författare)
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Reading Ability and Working Memory in School-Age Children Who Are Deaf and Hard of Hearing Using Cochlear Implants and/or Hearing Aids : A 3-Year Follow-Up on Computer-Based Phonics Training
- 2020
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Ingår i: Perspectives of the ASHA Special Interest Groups. - : American Speech-Language-Hearing Association. - 2381-473X. ; 5:6, s. 1388-1399
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Tidskriftsartikel (refereegranskat)abstract
- PurposeThe aim of the current study was to investigate reading ability in children who are deaf and hard of hearing (DHH) using cochlear implants (CI) or hearing aids (HA) 3 years after computer-assisted phonics intervention. Reading ability was examined in relation to cognitive and audiological aspects and compared to a reference group of children with typical hearing (TH).MethodParticipants were 73 Swedish primary school children (Mdn = 9 years). Fifty-five of the children were TH, and 18 children were DHH using CI (n = 10) or HA (n = 8). Twenty-seven of the children (all children who were DHH and nine of the children with TH) had participated in computer-based phonics intervention 3 years earlier. Children were assessed on word and nonword decoding, reading comprehension, and three working memory (WM) tasks. Age at diagnosis, age of amplification, and duration of unaided hearing loss formed the audiological variables.ResultsComparable word decoding skills and reading comprehension were observed in all three groups (CI, HA, and TH). Children with CI showed strong and significant correlations between two aspects of WM capacity (phonological and complex WM) and all aspects of reading. For children with TH, similar but weaker correlations as in children with CI was observed, and correlations with visual WM were also evident. In children with HA only, complex WM correlated strongly and significantly with nonword decoding. Duration of unaided hearing loss was the single audiological variable that was significantly associated with reading.ConclusionsThis 3-year follow-up showed overall positive reading results at the group level in children who are DHH. However, some children still lag behind their peers with TH. Early hearing experience and intervention are stressed as crucial factors in preventing negative outcomes in these children.
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