| 1. |
- Horn, Christian, 1978, et al.
(författare)
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Artificial Intelligence, 3D Documentation, and Rock Art—Approaching and Reflecting on the Automation of Identification and Classification of Rock Art Images
- 2022
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Ingår i: Journal of archaeological method and theory. - : Springer Science and Business Media LLC. - 1072-5369 .- 1573-7764. ; 29, s. 188-213
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Tidskriftsartikel (refereegranskat)abstract
- Rock art carvings, which are best described as petroglyphs, were produced by removing parts of the rock surface to create a negative relief. This tradition was particularly strong during the Nordic Bronze Age (1700–550 BC) in southern Scandinavia with over 20,000 boats and thousands of humans, animals, wagons, etc. This vivid and highly engaging material provides quantitative data of high potential to understand Bronze Age social structures and ideologies. The ability to provide the technically best possible documentation and to automate identification and classification of images would help to take full advantage of the research potential of petroglyphs in southern Scandinavia and elsewhere. We, therefore, attempted to train a model that locates and classifies image objects using faster region-based convolutional neural network (Faster-RCNN) based on data produced by a novel method to improve visualizing the content of 3D documentations. A newly created layer of 3D rock art documentation provides the best data currently available and has reduced inscribed bias compared to older methods. Several models were trained based on input images annotated with bounding boxes produced with different parameters to find the best solution. The data included 4305 individual images in 408 scans of rock art sites. To enhance the models and enrich the training data, we used data augmentation and transfer learning. The successful models perform exceptionally well on boats and circles, as well as with human figures and wheels. This work was an interdisciplinary undertaking which led to important reflections about archaeology, digital humanities, and artificial intelligence. The reflections and the success represented by the trained models open novel avenues for future research on rock art.
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| 2. |
- Fabian, ID, et al.
(författare)
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Travel burden and clinical presentation of retinoblastoma: analysis of 1024 patients from 43 African countries and 518 patients from 40 European countries
- 2021
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Ingår i: The British journal of ophthalmology. - : BMJ. - 1468-2079 .- 0007-1161. ; 105:10, s. 1435-1443
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Tidskriftsartikel (refereegranskat)abstract
- The travel distance from home to a treatment centre, which may impact the stage at diagnosis, has not been investigated for retinoblastoma, the most common childhood eye cancer. We aimed to investigate the travel burden and its impact on clinical presentation in a large sample of patients with retinoblastoma from Africa and Europe.MethodsA cross-sectional analysis including 518 treatment-naïve patients with retinoblastoma residing in 40 European countries and 1024 treatment-naïve patients with retinoblastoma residing in 43 African countries.ResultsCapture rate was 42.2% of expected patients from Africa and 108.8% from Europe. African patients were older (95% CI −12.4 to −5.4, p<0.001), had fewer cases of familial retinoblastoma (95% CI 2.0 to 5.3, p<0.001) and presented with more advanced disease (95% CI 6.0 to 9.8, p<0.001); 43.4% and 15.4% of Africans had extraocular retinoblastoma and distant metastasis at the time of diagnosis, respectively, compared to 2.9% and 1.0% of the Europeans. To reach a retinoblastoma centre, European patients travelled 421.8 km compared to Africans who travelled 185.7 km (p<0.001). On regression analysis, lower-national income level, African residence and older age (p<0.001), but not travel distance (p=0.19), were risk factors for advanced disease.ConclusionsFewer than half the expected number of patients with retinoblastoma presented to African referral centres in 2017, suggesting poor awareness or other barriers to access. Despite the relatively shorter distance travelled by African patients, they presented with later-stage disease. Health education about retinoblastoma is needed for carers and health workers in Africa in order to increase capture rate and promote early referral.
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| 3. |
- Hayes, Jerrard M, et al.
(författare)
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Fc Gamma Receptor Glycosylation Modulates the Binding of IgG Glycoforms : A Requirement for Stable Antibody Interactions
- 2014
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 13:12, s. 5471-5485
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Tidskriftsartikel (refereegranskat)abstract
- FcγRs play a critical role in the immune response following recognition of invading particles and tumor associated antigens by circulating antibodies. In the present study we investigated the role of FcγR glycosylation in the IgG interaction and observed a stabilizing role for receptor N-glycans. We performed a complete glycan analysis of the recombinant FcγRs (FcγRIa, FcγRIIa, FcγRIIb, FcγRIIIaPhe158/Val158, and FcγRIIIb) expressed in human cells and demonstrate that receptor glycosylation is complex and varied between receptors. We used surface plasmon resonance to establish binding patterns between rituximab and all receptors. Complex binding was observed for FcγRIa and FcγRIIIa. The IgG-FcγR interaction was further investigated using a combination of kinetic experiments and enzymatically deglycosylated FcγRIa and FcγRIIIaPhe158/Val158 receptors in an attempt to determine the underlying binding mechanism. We observed that antibody binding levels decreased for deglycosylated receptors, and at the same time, binding kinetics were altered and showed a more rapid approach to steady state, followed by an increase in the antibody dissociation rate. Binding of rituximab to deglycosylated FcγRIIIaPhe158 was now consistent with a 1:1 binding mechanism, while binding of rituximab to FcγRIIIaVal158 remained heterogeneous. Kinetic data support a complex binding mechanism, involving heterogeneity in both antibody and receptor, where fucosylated and afucosylated antibody forms compete in receptor binding and in receptor molecules where heterogeneity in receptor glycosylation plays an important role. The exact nature of receptor glycans involved in IgG binding remains unclear and determination of rate and affinity constants are challenging. Here, the use of more extended competition experiments appear promising and suggest that it may be possible to determine dissociation rate constants for high affinity afucosylated antibodies without the need to purify or express such variants. The data described provide further insight into the complexity of the IgG-FcγR interaction and the influence of FcγR glycosylation.
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| 4. |
- Melo, Nadia, et al.
(författare)
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The irritant receptor TRPA1 mediates the mosquito repellent effect of catnip
- 2021
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822. ; 31:9, s. 5-1994
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Tidskriftsartikel (refereegranskat)abstract
- Catnip (Nepeta cataria) is a common garden herb well known for its euphoric and hallucinogenic effects on domestic cats,1–3 for its medicinal properties,4,5 as well as for its powerful repellent action on insects.6,7 Catnip extracts have been proposed as a natural alternative to synthetic insect repellents, such as N,N-diethyl-3-methylbenzamide (DEET),8,9 but how catnip triggers aversion in insects is not known. Here, we show that, both in Drosophila melanogaster flies and Aedes aegypti mosquitoes, the major mediator of catnip repellency is the widely conserved chemical irritant receptor TRPA1. In vitro, both catnip extract and its active ingredient nepetalactone can directly activate fly and mosquito TRPA1. In vivo, D. melanogaster and Ae. aegypti TRPA1 mutants are no longer repelled by catnip and nepetalactone. Interestingly, our data show that some, but not all, fly and mosquito TRPA1 variants are catnip targets. Moreover, unlike the broad TRPA1 agonist allyl isothiocyanate (AITC) (an active ingredient of tear gas and wasabi), catnip does not activate human TRPA1. Our results support the use of catnip and nepetalactone as insect-selective irritants and suggest that, despite TRPA1’s broad conservation, insect TRPA1 can be targeted for the development of safe repellents. Catnip has been used for millennia as an insect repellent. Melo et al. find that catnip and its major iridoid component nepetalactone activate insect isoforms of the irritant receptor TRPA1. Mosquitoes lacking TRPA1 are no longer repelled by catnip. Catnip does not activate human TRPA1, and this supports its use as a safe natural mosquito repellent.
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| 5. |
- Wang, Li-San, et al.
(författare)
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Rarity of the Alzheimer Disease-Protective APP A673T Variant in the United States.
- 2015
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Ingår i: JAMA neurology. - : American Medical Association (AMA). - 2168-6157 .- 2168-6149. ; 72:2
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Tidskriftsartikel (refereegranskat)abstract
- Recently, a rare variant in the amyloid precursor protein gene (APP) was described in a population from Iceland. This variant, in which alanine is replaced by threonine at position 673 (A673T), appears to protect against late-onset Alzheimer disease (AD). We evaluated the frequency of this variant in AD cases and cognitively normal controls to determine whether this variant will significantly contribute to risk assessment in individuals in the United States.
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