32 research outputs found
Разработка метода формирования износостойких поверхностных слоев в технически чистом алюминии
Объектом исследования является технически чистый алюминий марки А7, подвергнутый азотированию в плазме несамостоятельного частотно-импульсного тлеющего разряда с полым катодом при низком давлении.
Цель работы – разработка метода формирования износостойких поверхностных слоев в технически чистом алюминии.
Проведены исследования механических и трибологических свойств материала (микротвердость, коэффициент износа, коэффициент трения).
В результате исследования выявлен режим азотирования, позволяющий кратно повысить трибологические и механических характеристики технически чистого алюминия марки А7.The subject of the study is technically pure aluminum of the A7, subjected to nitriding in the plasma of a frequency-pulse non-self-sustained glow discharge with a hollow cathode at low pressure.
The aim of the work is to development of a method for the formation of wear-resistant surface layers in technically pure aluminum.
Mechanical and tribological properties of the material (microhardness, wear coefficient, coefficient of friction) are studied.
As a result of the study, the nitriding mode was revealed, which allows to increase the tribological and mechanical characteristics of technically pure aluminum of the A7
Incidental findings on brain magnetic resonance imaging: systematic review and meta-analysis
Objective To quantify the prevalence of incidental findings on magnetic resonance imaging (MRI) of the brain
Genomic Relationships, Novel Loci, and Pleiotropic Mechanisms across Eight Psychiatric Disorders
Genetic influences on psychiatric disorders transcend diagnostic boundaries, suggesting substantial pleiotropy of contributing loci. However, the nature and mechanisms of these pleiotropic effects remain unclear. We performed analyses of 232,964 cases and 494,162 controls from genome-wide studies of anorexia nervosa, attention-deficit/hyper-activity disorder, autism spectrum disorder, bipolar disorder, major depression, obsessive-compulsive disorder, schizophrenia, and Tourette syndrome. Genetic correlation analyses revealed a meaningful structure within the eight disorders, identifying three groups of inter-related disorders. Meta-analysis across these eight disorders detected 109 loci associated with at least two psychiatric disorders, including 23 loci with pleiotropic effects on four or more disorders and 11 loci with antagonistic effects on multiple disorders. The pleiotropic loci are located within genes that show heightened expression in the brain throughout the lifespan, beginning prenatally in the second trimester, and play prominent roles in neurodevelopmental processes. These findings have important implications for psychiatric nosology, drug development, and risk prediction.Peer reviewe
The Anglo-Saxon migration and the formation of the early English gene pool.
The history of the British Isles and Ireland is characterized by multiple periods of major cultural change, including the influential transformation after the end of Roman rule, which precipitated shifts in language, settlement patterns and material culture1. The extent to which migration from continental Europe mediated these transitions is a matter of long-standing debate2-4. Here we study genome-wide ancient DNA from 460 medieval northwestern Europeans-including 278 individuals from England-alongside archaeological data, to infer contemporary population dynamics. We identify a substantial increase of continental northern European ancestry in early medieval England, which is closely related to the early medieval and present-day inhabitants of Germany and Denmark, implying large-scale substantial migration across the North Sea into Britain during the Early Middle Ages. As a result, the individuals who we analysed from eastern England derived up to 76% of their ancestry from the continental North Sea zone, albeit with substantial regional variation and heterogeneity within sites. We show that women with immigrant ancestry were more often furnished with grave goods than women with local ancestry, whereas men with weapons were as likely not to be of immigrant ancestry. A comparison with present-day Britain indicates that subsequent demographic events reduced the fraction of continental northern European ancestry while introducing further ancestry components into the English gene pool, including substantial southwestern European ancestry most closely related to that seen in Iron Age France5,6
Author Correction: The Anglo-Saxon migration and the formation of the early English gene pool.
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The Anglo-Saxon migration and the formation of the early English gene pool
The history of the British Isles and Ireland is characterized by multiple periods of major cultural change, including the influential transformation after the end of Roman rule, which precipitated shifts in language, settlement patterns and material culture1. The extent to which migration from continental Europe mediated these transitions is a matter of long-standing debate2,3,4. Here we study genome-wide ancient DNA from 460 medieval northwestern Europeans—including 278 individuals from England—alongside archaeological data, to infer contemporary population dynamics. We identify a substantial increase of continental northern European ancestry in early medieval England, which is closely related to the early medieval and present-day inhabitants of Germany and Denmark, implying large-scale substantial migration across the North Sea into Britain during the Early Middle Ages. As a result, the individuals who we analysed from eastern England derived up to 76% of their ancestry from the continental North Sea zone, albeit with substantial regional variation and heterogeneity within sites. We show that women with immigrant ancestry were more often furnished with grave goods than women with local ancestry, whereas men with weapons were as likely not to be of immigrant ancestry. A comparison with present-day Britain indicates that subsequent demographic events reduced the fraction of continental northern European ancestry while introducing further ancestry components into the English gene pool, including substantial southwestern European ancestry most closely related to that seen in Iron Age France5,6
7 Tesla MRI of microbleeds and white matter lesions as seen in vascular dementia
Purpose: To evaluate 7T MRI in the assessment of cerebrovascular alterations as seen in vascular dementia by means of detection of cerebral microbleeds (CMB) and depiction of white matter lesions (WML). 7T imaging was evaluated with respect to 1.5T. Materials and Methods: Ten healthy volunteers and 10 patients with CMBs and/or WMLs were examined at 1.5T and 7T using gradient-echo (T2*, SWI) and turbo-spin-echo sequences (FLAIR). Comparisons of image quality, CMB and WML detection rates between sequences and field strengths were performed. Results: Using high-resolution SWI at 7T 129 CMBs were detected compared to 75 at 1.5T using clinical SWI.With T2* at 7T 101 CMBs could be detected (33 CMBs at 1.5T). Lesion sizes were significantly larger for higher field strength. FLAIR images at 7T highlighted WMLs known from 1.5T with comparable extent. Gray and white matter contrast in FLAIR was slightly better at 1.5T, whereas image resolution and contrast of theWMLs to surrounding tissue was higher at 7T. Conclusion: By means of higher sensitivity for CMBs, 7T (SWI, T2*) might have significant impact on the early detection, diagnosis, and optimized antithrombotic therapy of cerebrovascular patients (eg, vascular dementia) in the future. Given the current state of technical development, 7T is approximately on par with 1.5T in the depiction of WMLs and their distribution, but holds the potential for future improvements