227 research outputs found
Eliciting usage contexts of safety-critical medical devices
This position paper outlines our approach to improve the usage choice of suitable devices in different health care environments (contexts). Safety-critical medical devices are presumed to have undergone a thorough (user-centred) design process to optimize the device for the intended purpose, user group and environment. However, in real-life health care scenarios, actual usage may not reflect the original design parameters. We suggest the identification of further usage contexts for safety-critical medical devices through ethnographic and other studies, to assist better modelling of the challenges of different usage environments. In combination with system and interaction models, these context models can then be used for decision-support in choosing medical devices that are suitable for the intended environment
A Nexus Model of Restricted Interests in Autism Spectrum Disorder
Restricted interests (RIs) in autism spectrum disorder (ASD) are clinically impairing interests of unusual focus or intensity. They are a subtype of restricted and repetitive behaviors which are one of two diagnostic criteria for the disorder. Despite the near ubiquity of RIs in ASD, the neural basis for their development is not well understood. However, recent cognitive neuroscience findings from nonclinical samples and from individuals with ASD shed light on neural mechanisms that may explain the emergence of RIs. We propose the nexus model of RIs in ASD, a novel conceptualization of this symptom domain that suggests that RIs may reflect a co-opting of brain systems that typically serve to integrate complex attention, memory, semantic, and social communication functions during development. The nexus model of RIs hypothesizes that when social communicative development is compromised, brain functions typically located within the lateral surface of cortex may expand into social processing brain systems and alter cortical representations of various cognitive functions during development. These changes, in turn, promote the development of RIs as an alternative process mediated by these brain networks. The nexus model of RIs makes testable predictions about reciprocal relations between the impaired development of social communication and the emergence of RIs in ASD and suggests novel avenues for treatment development
Wafer-scale fabrication of 2D nanostructures via thermomechanical nanomolding
With shrinking dimensions in integrated circuits, sensors, and functional
devices, there is a pressing need to develop nanofabrication techniques with
simultaneous control of morphology, microstructure, and material composition
over wafer length scales. Current techniques are largely unable to meet all
these conditions, suffering from poor control of morphology and defect
structure or requiring extensive optimization or post-processing to achieve
desired nanostructures. Recently, thermomechanical nanomolding (TMNM) has been
shown to yield single-crystalline, high aspect ratio nanowires of metals,
alloys, and intermetallics over wafer-scale distances. Here, we extend TMNM for
wafer-scale fabrication of 2D nanostructures. Using Cu, we successfully
nanomold Cu nanoribbons with widths < 50 nm, depths ~ 0.5-1 microns and lengths
~ 7 mm into Si trenches at conditions compatible with back end of line
processing. Through SEM cross-section imaging and 4D-STEM grain orientation
maps, we show that the grain size of the bulk feedstock is transferred to the
nanomolded structures up to and including single crystal Cu. Based on the
retained microstructures of molded 2D Cu, we discuss the deformation mechanism
during molding for 2D TMNM.Comment: 4 figure
Double Object Constructions in Korean: Asymmetry between Theme and Goal
Much of the generative studies on the double object constructions in English have shown that there exists an asymmetrical c-command relation between the Theme argument and the Goal argument: the Goal uniformly c-commands the Theme at D-structure. This paper attempts to prove that Korean also exhibits an asymmetric relation between the Theme and Goal in double object constructions, but it is the Theme that asymmetrically c-commands the Goal at D-structure in Korean
SiGe-On-Insulator (SGOI): Two Structures for CMOS Application
Two SiGe-on-insulator (SGOI) structures for CMOS application are presented: surface-channel strained-Si on SGOI (SSOI) and dual-channel SGOI structures. Comparisons between two structures are made from both device performance and CMOS process point of view. We have demonstrated both structures on SGOI, and have fabricated n-MOSFET’s and p-MOSFET’s on those two structures respectively. Device characteristics are presented. The devices show enhancement on both electron and hole mobilities.Singapore-MIT Alliance (SMA
Perivascular cells induce microglial phagocytic states and synaptic engulfment via SPP1 in mouse models of Alzheimer's disease
Alzheimer's disease (AD) is characterized by synaptic loss, which can result from dysfunctional microglial phagocytosis and complement activation. However, what signals drive aberrant microglia-mediated engulfment of synapses in AD is unclear. Here we report that secreted phosphoprotein 1 (SPP1/osteopontin) is upregulated predominantly by perivascular macrophages and, to a lesser extent, by perivascular fibroblasts. Perivascular SPP1 is required for microglia to engulf synapses and upregulate phagocytic markers including C1qa, Grn and Ctsb in presence of amyloid-β oligomers. Absence of Spp1 expression in AD mouse models results in prevention of synaptic loss. Furthermore, single-cell RNA sequencing and putative cell-cell interaction analyses reveal that perivascular SPP1 induces microglial phagocytic states in the hippocampus of a mouse model of AD. Altogether, we suggest a functional role for SPP1 in perivascular cells-to-microglia crosstalk, whereby SPP1 modulates microglia-mediated synaptic engulfment in mouse models of AD
The Relationship between Subjective and Objective Parameters in CT Phantom Image Evaluation
Objective: To evaluate whether there is a relationship between subjective parameters determined by a reviewer (spatial resolution, low contrast resolution, and artifacts) and objective parameters (the CT number of water, noise, and image uniformity) in CT phantom image evaluations. Materials and Methods: We reviewed the CT results of phantom image evaluations conducted by Korean Institute for Accreditation of Medical Image (KIAMI) from May 2007 to June 2007. We compared the objective parameters against the pass or fail groups for the subjective parameters. We also evaluated whether there is a relationship between the artifact types and the other subjective parameters. Results: The mean noise value was significantly higher in the fail groups for the subjective parameters compared to the pass groups (p = 0.006). Specifically, noise and low contrast resolution were found to have a statistically significant positive correlation (r = 0. 183, p < 0.001). In the fail group for low contrast resolution, the failure due to artifacts was significantly higher than the pass group (p < 0.001). In contrast, no statistically significant differences were found for the mean CT number of water, noise, or image uniformity based on the types of artifacts. Conclusion: Subjective CT image parameters evaluated by a reviewer correlate with objectively measured parameters, especially noise. Therefore, a stricter noise standard might be able to improve the subjective parameters results, such as low contrast resolution.Park HJ, 2008, KOREAN J RADIOL, V9, P354, DOI 10.3348/kjr.2008.9.4.354IM TH, 2007, 1 KIAMI, P1*KIAMI DEP ED, 2006, WORKSH EX QUAL ASS P, P141*FLUK CORP, 2005, NUCL ASS 76 410 4130*KIAMI DEP ED, 2005, WORKSH EX QUAL ASS P, P13McCollough CH, 2004, MED PHYS, V31, P2423, DOI 10.1118/1.1769632MCCOLLOUGH CM, 2000, CATEGORICAL COURSE D, P189WIL R, 1998, CT IMAGE QUALITYEUCLID S, 1994, COMPUT TOMOGR, P174BETHESDA MD, 1988, 99 NCRPJUDY PF, 1977, 1 AAPM*ACR, CT ACCR PROGR REQ
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A Nexus Model of Restricted Interests in Autism Spectrum Disorder
Restricted interests (RIs) in autism spectrum disorder (ASD) are clinically impairing interests of unusual focus or intensity. They are a subtype of restricted and repetitive behaviors which are one of two diagnostic criteria for the disorder. Despite the near ubiquity of RIs in ASD, the neural basis for their development is not well understood. However, recent cognitive neuroscience findings from nonclinical samples and from individuals with ASD shed light on neural mechanisms that may explain the emergence of RIs. We propose the nexus model of RIs in ASD, a novel conceptualization of this symptom domain that suggests that RIs may reflect a co-opting of brain systems that typically serve to integrate complex attention, memory, semantic, and social communication functions during development. The nexus model of RIs hypothesizes that when social communicative development is compromised, brain functions typically located within the lateral surface of cortex may expand into social processing brain systems and alter cortical representations of various cognitive functions during development. These changes, in turn, promote the development of RIs as an alternative process mediated by these brain networks. The nexus model of RIs makes testable predictions about reciprocal relations between the impaired development of social communication and the emergence of RIs in ASD and suggests novel avenues for treatment development.</p
Perivascular cells induce microglial phagocytic states and synaptic engulfment via SPP1 in mouse models of Alzheimer\u27s disease.
Alzheimer\u27s disease (AD) is characterized by synaptic loss, which can result from dysfunctional microglial phagocytosis and complement activation. However, what signals drive aberrant microglia-mediated engulfment of synapses in AD is unclear. Here we report that secreted phosphoprotein 1 (SPP1/osteopontin) is upregulated predominantly by perivascular macrophages and, to a lesser extent, by perivascular fibroblasts. Perivascular SPP1 is required for microglia to engulf synapses and upregulate phagocytic markers including C1qa, Grn and Ctsb in presence of amyloid-β oligomers. Absence of Spp1 expression in AD mouse models results in prevention of synaptic loss. Furthermore, single-cell RNA sequencing and putative cell-cell interaction analyses reveal that perivascular SPP1 induces microglial phagocytic states in the hippocampus of a mouse model of AD. Altogether, we suggest a functional role for SPP1 in perivascular cells-to-microglia crosstalk, whereby SPP1 modulates microglia-mediated synaptic engulfment in mouse models of AD
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