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- Rasmussen, Morten, et al.
(författare)
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The genome of a Late Pleistocene human from a Clovis burial site in western Montana
- 2014
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 506:7487, s. 225-229
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Tidskriftsartikel (refereegranskat)abstract
- Clovis, with its distinctive biface, blade and osseous technologies, is the oldest widespread archaeological complex defined in North America, dating from 11,100 to 10,700 C-14 years before present (BP) (13,000 to 12,600 calendar years BP)(1,2). Nearly 50 years of archaeological research point to the Clovis complex as having developed south of the North American ice sheets from an ancestral technology(3). However, both the origins and the genetic legacy of the people who manufactured Clovis tools remain under debate. It is generally believed that these people ultimately derived from Asia and were directly related to contemporary Native Americans(2). An alternative, Solutrean, hypothesis posits that the Clovis predecessors emigrated from southwestern Europe during the Last Glacial Maximum(4). Here we report the genome sequence of a male infant (Anzick-1) recovered from the Anzick burial site in western Montana. The human bones date to 10,705 +/- 35 C-14 years BP (approximately 12,707-12,556 calendar years BP) and were directly associated with Clovis tools. We sequenced the genome to an average depth of 14.4x and show that the gene flow from the Siberian Upper Palaeolithic Mal'ta population(5) into Native American ancestors is also shared by the Anzick-1 individual and thus happened before 12,600 years BP. We also show that the Anzick-1 individual is more closely related to all indigenous American populations than to any other group. Our data are compatible with the hypothesis that Anzick-1 belonged to a population directly ancestral to many contemporary Native Americans. Finally, we find evidence of a deep divergence in Native American populations that predates the Anzick-1 individual.
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- Ringlander, Johan, et al.
(författare)
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Enrichment Reveals Extensive Integration of Hepatitis B Virus DNA in Hepatitis Delta Virus-Infected Patients
- 2024
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Ingår i: JOURNAL OF INFECTIOUS DISEASES. - 0022-1899 .- 1537-6613.
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Tidskriftsartikel (refereegranskat)abstract
- Background. Hepatitis B virus (HBV) DNA may become integrated into the human genome of infected human hepatocytes. Expression of integrations can produce the surface antigen (HBsAg) that is required for synthesis of hepatitis D virus (HDV) particles and the abundant subviral particles in the blood of HBV- and HDV-infected subjects. Knowledge about the extent and variation of HBV integrations and impact on chronic HDV is still limited. Methods. We investigated 50 pieces of liver explant tissue from 5 patients with hepatitis D-induced cirrhosis, using a deep-sequencing strategy targeting HBV RNA. Results. We found that integrations were abundant and highly expressed, with large variation in the number of integration-derived (HBV/human chimeric) reads, both between and within patients. The median number of unique integrations for each patient correlated with serum levels of HBsAg. However, most of the HBV reads represented a few predominant integrations. Conclusions. The results suggest that HBV DNA integrates in a large proportion of hepatocytes, and that the HBsAg output from these integrations vary >100-fold depending on clone size and expression rate. A small proportion of the integrations seems to determine the serum levels of HBsAg and HDV RNA in HBV/HDV coinfected patients with liver cirrhosis.
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- Appelgren, Patrik, et al.
(författare)
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Interaction between solid copper jets and powerful electrical current pulses
- 2011
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Ingår i: Journal of applied mechanics. - : ASME International. - 0021-8936 .- 1528-9036. ; 78:2
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Tidskriftsartikel (refereegranskat)abstract
- The interaction between a solid copper jet and an electric current pulse is studied. Copper jets that were created by a shaped-charge device were passed through an electrode configuration consisting of two aluminum plates with a separation distance of 150 mm. The electrodes were connected to a pulsed-power supply delivering a current pulse with amplitudes up to 250 kA. The current and voltages were measured, providing data on energy deposition in the jet and electrode contact region, and flash X-ray diagnostics were used to depict the jet during and after electrification. The shape of, and the velocity distributions along, the jet has been used to estimate the correlation between the jet mass flow through the electrodes and the electrical energy deposition. On average, 2.8 kJ/g was deposited in the jet and electrode region, which is sufficient to bring the jet up to the boiling point. A model based on the assumption of a homogenous current flow through the jet between the electrodes underestimates the energy deposition and the jet resistance by a factor 5 compared with the experiments, indicating a more complex current flow through the jet. The experimental results indicate the following mechanism for the enhancement of jet breakup. When electrified, the natural-formed necks in the jet are subjected to a higher current density compared with other parts of the jet. The higher current density results in a stronger heating and a stronger magnetic pinch force. Eventually, the jet material in the neck is evaporated and explodes electrically, resulting in a radial ejection of vaporized jet material.
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- Berg, Hans E., et al.
(författare)
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Threshold-automated CT measurements of muscle size and radiological attenuation in multiple lower-extremity muscles of older individuals
- 2020
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Ingår i: Clinical Physiology and Functional Imaging. - : WILEY. - 1475-0961 .- 1475-097X. ; 40:3, s. 165-172
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Tidskriftsartikel (refereegranskat)abstract
- Muscle atrophy and fat infiltration, two indicators of deconditioning and weakness in elderly frail patients, are typically assessed by means of manual image analysis from computed tomography (CT) scans. As this time-consuming image analysis limits its wider use in clinical studies, the use of tissue thresholds to semi-automatically assess muscle composition has been suggested. Here, we aimed to investigate the relationship between manual and semi-automated analysis of both cross-sectional area (CSA) and radiological attenuation (RA), in multiple muscles of the lower extremities in aged (77 +/- 6 years) sedentary individuals (n = 40). The participants underwent CT scans of their lower limbs, including hip, thigh and calf muscles. The subsequent analysis of CSA and RA was conducted using both manual segmentation and semi-automatic thresholds (-30 to +150 Hounsfield units). Automated measurements were generally strongly correlated with manually encircled CSA in all muscle groups (R = 0.79-0.99, p < .05) and shortened the analysis time by 70% (p < .05). In m. iliopsoas, however, the CSA became overestimated (15%, p < .05) with thresholded measurements, while the assessment of both CSA and RA was underestimated in muscles with high-fat content (i.e., the gluteal muscles) and in individuals with high-fat infiltration. In conclusion, using the semi-automated technique with conventional thresholds is a time-saving method that delivers accurate gross size of the muscle groups, particularly in the thigh. However, caution should be exercised when using semi-automated techniques for assessing CSA and fat infiltration in muscles with high-fat content.
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