549 research outputs found
Native Point Defect Measurement and Manipulation in ZnO Nanostructures
This review presents recent research advances in measuring native point defects in ZnO
nanostructures, establishing how these defects affect nanoscale electronic properties, and developing
new techniques to manipulate these defects to control nano- and micro- wire electronic properties.
From spatially-resolved cathodoluminescence spectroscopy, we now know that electrically-active
native point defects are present inside, as well as at the surfaces of, ZnO and other semiconductor
nanostructures. These defects within nanowires and at their metal interfaces can dominate
electrical contact properties, yet they are sensitive to manipulation by chemical interactions, energy
beams, as well as applied electrical fields. Non-uniform defect distributions are common among
semiconductors, and their effects are magnified in semiconductor nanostructures so that their
electronic effects are significant. The ability to measure native point defects directly on a nanoscale
and manipulate their spatial distributions by multiple techniques presents exciting possibilities for
future ZnO nanoscale electronics
Changes in cerebral vascular reactivity and structure following prolonged exposure to high altitude in humans.
Although high-altitude exposure can lead to neurocognitive impairment, even upon return to sea level, it remains unclear the extent to which brain volume and regional cerebral vascular reactivity (CVR) are altered following high-altitude exposure. The purpose of this study was to simultaneously determine the effect of 3 weeks at 5050 m on: (1) structural brain alterations; and (2) regional CVR after returning to sea level for 1 week. Healthy human volunteers (n = 6) underwent baseline and follow-up structural and functional magnetic resonance imaging (MRI) at rest and during a CVR protocol (end-tidal PCO2 reduced by -10, -5 and increased by +5, +10, and +15 mmHg from baseline). CVR maps (% mmHg(-1)) were generated using BOLD MRI and brain volumes were estimated. Following return to sea level, whole-brain volume and gray matter volume was reduced by 0.4 ± 0.3% (P < 0.01) and 2.6 ± 1.0% (P < 0.001), respectively; white matter was unchanged. Global gray matter CVR and white matter CVR were unchanged following return to sea level, but CVR was selectively increased (P < 0.05) in the brainstem (+30 ± 12%), hippocampus (+12 ± 3%), and thalamus (+10 ± 3%). These changes were the result of improvement and/or reversal of negative CVR to positive CVR in these regions. Three weeks of high-altitude exposure is reflected in loss of gray matter volume and improvements in negative CVR
Changes in cerebral vascular reactivity and structure following prolonged exposure to high altitude in humans
ICâP2â074: Differentiating amnestic MCI converting to probable AD from stable amnestic MCI using FDGâPET and an ADârelated hypometabolism overlap index
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152594/1/alzjjalz200805067.pd
P2â037: Categorical and correlational analyses of baseline fluorodeoxyglucose positron emission tomography images from the Alzheimerâs disease neuroimaging initiative
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152628/1/alzjjalz2008051118.pd
P2â037: Categorical and correlational analyses of baseline fluorodeoxyglucose positron emission tomography images from the Alzheimerâs disease neuroimaging initiative
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152628/1/alzjjalz2008051118.pd
P2â037: Categorical and correlational analyses of baseline fluorodeoxyglucose positron emission tomography images from the Alzheimerâs disease neuroimaging initiative
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152628/1/alzjjalz2008051118.pd
Epidemiology of fractures and their treatment in Malawi: Results of a multicentre prospective registry study to guide orthopaedic care planning
IMPORTANCE: Injuries cause 30% more deaths than HIV, TB and malaria combined, and a prospective fracture care registry was established to investigate the fracture burden and treatment in Malawi to inform evidence-based improvements. OBJECTIVE: To use the analysis of prospectively-collected fracture data to develop evidence-based strategies to improve fracture care in Malawi and other similar settings. DESIGN: Multicentre prospective registry study. SETTING: Two large referral centres and two district hospitals in Malawi. PARTICIPANTS: All patients with a fracture (confirmed by radiographs)âincluding patients with multiple fracturesâwere eligible to be included in the registry. EXPOSURE: All fractures that presented to two urban central and two rural district hospitals in Malawi over a 3.5-year period (September 2016 to March 2020). MAIN OUTCOME(S) AND MEASURE(S): Demographics, characteristics of injuries, and treatment outcomes were collected on all eligible participants. RESULTS: Between September 2016 and March 2020, 23,734 patients were enrolled with a median age of 15 years (interquartile range: 10â35 years); 68.7% were male. The most common injuries were radius/ulna fractures (n = 8,682, 36.8%), tibia/fibula fractures (n = 4,036, 17.0%), humerus fractures (n = 3,527, 14.9%) and femoral fractures (n = 2,355, 9.9%). The majority of fractures (n = 21,729, 91.6%) were treated by orthopaedic clinical officers; 88% (20,885/2,849) of fractures were treated non-operatively, and 62.7% were treated and sent home on the same day. Open fractures (OR:53.19, CI:39.68â72.09), distal femoral fractures (OR:2.59, CI:1.78â3.78), patella (OR:10.31, CI:7.04â15.07), supracondylar humeral fractures (OR:3.10, CI:2.38â4.05), ankle fractures (OR:2.97, CI:2.26â3.92) and tibial plateau fractures (OR:2.08, CI:1.47â2.95) were more likely to be treated operatively compared to distal radius fractures. CONCLUSIONS AND RELEVANCE: The current model of fracture care in Malawi is such that trained orthopaedic surgeons manage fractures operatively in urban referral centres whereas orthopaedic clinical officers mainly manage fractures non-operatively in both district and referral centres. We recommend that orthopaedic surgeons should supervise orthopaedic clinical officers to manage non operative injuries in central and district hospitals. There is need for further studies to assess the clinical and patient reported outcomes of these fracture cases, managed both operatively and non-operatively
In search of the authentic nation: landscape and national identity in Canada and Switzerland
While the study of nationalism and national identity has flourished in the last decade, little attention has been devoted to the conditions under which natural environments acquire significance in definitions of nationhood. This article examines the identity-forming role of landscape depictions in two polyethnic nation-states: Canada and Switzerland. Two types of geographical national identity are identified. The first â what we call the ânationalisation of natureââ portrays zarticular landscapes as expressions of national authenticity. The second pattern â what we refer to as the ânaturalisation of the nationââ rests upon a notion of geographical determinism that depicts specific landscapes as forces capable of determining national identity. The authors offer two reasons why the second pattern came to prevail in the cases under consideration: (1) the affinity between wild landscape and the Romantic ideal of pure, rugged nature, and (2) a divergence between the nationalist ideal of ethnic homogeneity and the polyethnic composition of the two societies under consideration
Light Microsopy Module, International Space Station Premier Automated Microscope
The Light Microscopy Module (LMM) was launched to the International Space Station (ISS) in 2009 and began science operations in 2010. It continues to support Physical and Biological scientific research on ISS. During 2015, if all goes as planned, five experiments will be completed: [1] Advanced Colloids Experiments with a manual sample base -3 (ACE-M-3), [2] the Advanced Colloids Experiment with a Heated Base -1 (ACE-H-1), [3] (ACE-H-2), [4] the Advanced Plant Experiment -03 (APEX-03), and [5] the Microchannel Diffusion Experiment (MDE). Preliminary results, along with an overview of present and future LMM capabilities will be presented; this includes details on the planned data imaging processing and storage system, along with the confocal upgrade to the core microscope. [1] New York University: Paul Chaikin, Andrew Hollingsworth, and Stefano Sacanna, [2] University of Pennsylvania: Arjun Yodh and Matthew Gratale, [3] a consortium of universities from the State of Kentucky working through the Experimental Program to Stimulate Competitive Research (EPSCoR): Stuart Williams, Gerold Willing, Hemali Rathnayake, et al., [4] from the University of Florida and CASIS: Anna-Lisa Paul and Rob Ferl, and [5] from the Methodist Hospital Research Institute from CASIS: Alessandro Grattoni and Giancarlo Canavese
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