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- Barton, Nick, et al.
(författare)
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New insights into the late Middle Stone Age occupation of Oued elAkarit, southern Tunisia
- 2021
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Ingår i: Libyan Studies. - : Cambridge University Press. - 0263-7189 .- 2052-6148. ; 52, s. 12-35
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Tidskriftsartikel (refereegranskat)abstract
- This article reports on a new project to investigate the activities of early Homo sapiens in the area of the Chotts ‘megalake’ in southernTunisia. Excavations in 2015 and 2019 at Oued el Akarit revealed one of a number of Middle Stone Age (MSA) horizons near the topof a long sequence of Upper Pleistocene deposits. The site identified as Oued el Akarit (Sondage 8) consists of lithic artefacts, bone fragmentsof large ungulates and pieces of ostrich eggshell. Many of the objects are burnt. Excavation of about nine square metres revealed thatthese were associated with a lightly trampled and combusted occupation surface. Amongst the identified artefacts were Levallois flakes someof which could be refitted, thereby indicating the generally undisturbed nature of the occupation. The lithic finds also included side scrapersand other tools diagnostic of the MSA but significantly no bifacial or tanged tools. OSL (Optically Stimulated Luminescence) dating of thesediments and AMS (Accelerator Mass Spectrometry) radiocarbon dating of ostrich eggshell have produced uncalibrated age determinationsin the range 37,000–40,000 years ago, one of the youngest ages for MSA sites in the region. This is the first example of a securely dated laterMSA occupation in a riparian environment in south-eastern Tunisia
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- Marger, L, et al.
(författare)
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Identification of Type-H-like Blood Vessels in a Dynamic and Controlled Model of Osteogenesis in Rabbit Calvarium
- 2022
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Ingår i: Materials (Basel, Switzerland). - : MDPI AG. - 1996-1944. ; 15:13
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Tidskriftsartikel (refereegranskat)abstract
- Angiogenesis and bone regeneration are closely interconnected processes. Whereas type-H blood vessels are abundantly found in the osteogenic zones during endochondral long bone development, their presence in flat bones’ development involving intramembranous mechanisms remains unclear. Here, we hypothesized that type-H-like capillaries that highly express CD31 and Endomucin (EMCN), may be present at sites of intramembranous bone development and participate in the control of osteogenesis. A rabbit model of calvarial bone augmentation was used in which bone growth was controlled over time (2–4 weeks) using a particulate bone scaffold. The model allowed the visualization of the entire spectrum of stages throughout bone growth in the same sample, i.e., active ossification, osteogenic activity, and controlled inflammation. Using systematic mRNA hybridization, the formation of capillaries subpopulations (CD31–EMCN staining) over time was studied and correlated with the presence of osteogenic precursors (Osterix staining). Type-H-like capillaries strongly expressing CD31 and EMCN were identified and described. Their presence increased gradually from the regenerative zone up to the osteogenic zone, at 2 and 4 weeks. Type-H-like capillaries may thus represent the initial vascular support encountered in flat bones’ development and which organize osteogenic niches.
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