15 research outputs found
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Analysis of the Importance of Extension in Accounting for the Post-Carboniferous Subsidence of the North Sea Basin
Post Carboniferous sedimentary deposition in the Central North Sea basins can be separated into three major periods: Permian, Triassic and mid-Jurassic through present. Most efforts to explain the basin within an extensional framework have concentrated on the post mid-Jurassic subsidence. These efforts have ignored the large amount of prior extension required to account for the observed crustal thinning and the substantial Permian and Triassic sediment fill. In addition the models predict a mid-Jurassic through early Cretaceous extension that significantly exceeds estimates of the horizontal displacement observed on high angle faults on multichannel seismic lines. We show in areas of minimal pre-Permian subsidence that adding two earlier phase extensions, one in the late Carboniferous through early Permian and the other in the Triassic produces a nearly horizontal late Carboniferous crustal thickness. The time-dependent extensional model required to account for the three periods of sediment deposition gives an excellent match to the observed subsidence history of the basement. We present an analysis of a recent seismic reflection line nm across the Central Graben in the vicinity of published refraction and well data. We show that the extension required in the third phase of the three phase model is compatible with the observed displacement on the high angle mid-Jurassic through early Cretaceous faults. However, we find no evidence for major extension either in the Triassic or late Carboniferous through early Permian.Institute for Geophysic
Advanced High Temperature Structural Seals
This program addresses the development of high temperature structural seals for control surfaces for a new generation of small reusable launch vehicles. Successful development will contribute significantly to the mission goal of reducing launch cost for small, 200 to 300 pound payloads. Development of high temperature seals is mission enabling. For instance, ineffective control surface seals can result in high temperature (3100 F) flows in the elevon area exceeding structural material limits. Longer sealing life will allow use for many missions before replacement, contributing to the reduction of hardware, operation and launch costs
Advanced High Temperature Structural Seals
This program addresses the development of high temperature structural seals for control surfaces for a new generation of small reusable launch vehicles. Successful development will contribute significantly to the mission goal of reducing launch cost for small, 200 to 300 lb payloads. Development of high temperature seals is mission enabling. For instance, ineffective control surface seals can result in high temperature (3100 F) flows in the elevon area exceeding structural material limits. Longer sealing life will allow use for many missions before replacement, contributing to the reduction of hardware, operation and launch costs. During the first phase of this program the existing launch vehicle control surface sealing concepts were reviewed, the aerothermal environment for a high temperature seal design was analyzed and a mock up of an arc-jet test fixture for evaluating seal concepts was fabricated
Identification of a protective microglial state mediated by miR-155 and interferon-γ signaling in a mouse model of Alzheimer’s disease
Microglia play a critical role in brain homeostasis and disease progression. In neurodegenerative conditions, microglia acquire the neurodegenerative phenotype (MGnD), whose function is poorly understood. MicroRNA-155 (miR-155), enriched in immune cells, critically regulates MGnD. However, its role in Alzheimer’s disease (AD) pathogenesis remains unclear. Here, we report that microglial deletion of miR-155 induces a pre-MGnD activation state via interferon-γ (IFN-γ) signaling, and blocking IFN-γ signaling attenuates MGnD induction and microglial phagocytosis. Single-cell RNA-sequencing analysis of microglia from an AD mouse model identifies Stat1 and Clec2d as pre-MGnD markers. This phenotypic transition enhances amyloid plaque compaction, reduces dystrophic neurites, attenuates plaque-associated synaptic degradation and improves cognition. Our study demonstrates a miR-155-mediated regulatory mechanism of MGnD and the beneficial role of IFN-γ-responsive pre-MGnD in restricting neurodegenerative pathology and preserving cognitive function in an AD mouse model, highlighting miR-155 and IFN-γ as potential therapeutic targets for AD
Digitalization in restorative dentistry
igitalization is the first step involving a digital restorative dentistry workflow. Although the digitalization process was initially confined to CAD/CAM (computer-aided design/computer-aided manufacturing) dental procedures, nowadays a much wider range of dental procedures have been revolutionized by their ongoing digitalization. Digitalization consists basically of converting any physical 2D or 3D volume into an electronic information language codified in terms of only two possible digits (0 or 1) normally contained in an informatic file.
The number of digitalized procedures and devices that have been incorporated into restorative dentistry is substantially growing. Digital photograph cameras, spectrophotometers for tooth shade matching, intraoral and extraoral scanners and 2D/3D radiological devices, spectrophotogrammetry, facial scanners, and jaw track motion systems are the main devices used to obtain digital information in restorative dentistry. The aim of this chapter is to describe to the reader the characteristics of every single family of devices as well as their specific nomenclature, features, and the types of file use