67,726 research outputs found
The UN-SUSTAINABLE Match in HCV Recipients. Evidences from the Italian D-MELD Study on Balancing Donor-Recipient Risk Factors
No full textThe UN-SUSTAINABLE Match in HCV Recipients. Evidences from the Italian D-MELD Study on Balancing Donor-Recipient Risk Factor
Hippocampal sulcal cavities prevalence, risk factors and association with cognitive performance. The SMART-Medea study and PREDICT-MR study
No full textHippocampal sulcal cavities (HSCs) are frequently observed on MRI, but their etiology and relevance is unclear. HSCs may be anatomical variations, or result from pathology. We assessed the presence of HSCs, and their cross-sectional association with demographics, vascular risk factors and cognitive functioning in two study samples. Within a random sample of 92 patients with vascular disease from the SMART-Medea study (mean age = 62, SD = 9 years) and 83 primary care patients from the PREDICT-MR study (mean age = 62, SD = 12 years) one rater manually scored HSCs at 1.5 T 3D T1-weighted coronal images blind to patient information. We estimated relative risks of age, sex and vascular risk factors with presence of HSCs using Poisson regression with log-link function and robust standard errors adjusted for age and sex. Using ANCOVA adjusted for age, sex, and education we estimated the association of the number of HSCs with memory, executive functioning, speed, and working memory. In the SMART-Medea study HSCs were present in 65% and in 52% in the PREDICT-MR study (χ2 = 2.99, df = 1, p = 0.08). In both samples, no significant associations were observed between presence of HSCs and age (SMART-Medea: RR = 1.00; 95%CI 0.98-1.01; PREDICT-MR: RR = 1.01; 95%CI 0.99-1.03), sex, or vascular risk factors. Also, no associations between HSCs and cognitive functioning were found in either sample. HSCs are frequently observed on 1.5 T MRI. Our findings suggest that, in patients with a history of vascular disease and primary care attendees, HSCs are part of normal anatomic variation of the human hippocampus rather than markers of pathology
Carotid Artery Stenosis and Progression of Hemispheric Brain Atrophy: The SMART-MR Study
No full textINTRODUCTION: It has been hypothesized that carotid artery stenosis (CAS) may lead to greater atrophy of subserved brain regions; however, prospective studies on the impact of CAS on progression of hemispheric brain atrophy are lacking. We examined the association between CAS and progression of hemispheric brain atrophy. METHODS: We included 654 patients (57 ± 9 years) of the SMART-MR study, a prospective cohort study of patients with manifest arterial disease. Patients had baseline CAS duplex measurements and a 1.5T brain MRI at baseline and after 4 years of follow-up. Mean change in hemispheric brain volumes (% of intracranial volume [ICV]) was estimated between baseline and follow-up for left-sided and right-sided CAS across three degrees of stenosis (mild [≤29%], moderate [30-69%], and severe [≥70%]), adjusting for demographics, cerebrovascular risk factors, and brain infarcts. RESULTS: Mean decrease in left and right hemispheric brain volumes was 1.15% ICV and 0.82% ICV, respectively, over 4 years of follow-up. Severe right-sided CAS, compared to mild CAS, was associated with a greater decrease in volume of the left hemisphere (B = -0.49% ICV, 95% CI: -0.86 to -0.13) and more profoundly of the right hemisphere (B = -0.90% ICV, 95% CI: -1.27 to -0.54). This pattern was independent of cerebrovascular risk factors, brain infarcts, and white matter hyperintensities on MRI, and was also observed when accounting for the presence of severe bilateral CAS. Increasing degrees of left-sided CAS, however, was not associated with greater volume loss of the left or right hemisphere. CONCLUSIONS: Our data indicate that severe (≥70%) CAS could represent a risk factor for greater ipsilateral brain volume loss, independent of cerebrovascular risk factors, brain infarcts, or white matter hyperintensities on MRI. Further longitudinal studies in other cohorts are warranted to confirm this novel finding
Reduced parenchymal cerebral blood flow is associated with greater progression of brain atrophy: The SMART-MR study
No full textGlobal cerebral hypoperfusion may be involved in the aetiology of brain atrophy; however, long-term longitudinal studies on this relationship are lacking. We examined whether reduced cerebral blood flow was associated with greater progression of brain atrophy. Data of 1165 patients (61 ± 10 years) from the SMART-MR study, a prospective cohort study of patients with arterial disease, were used of whom 689 participated after 4 years and 297 again after 12 years. Attrition was substantial. Total brain volume and total cerebral blood flow were obtained from magnetic resonance imaging scans and expressed as brain parenchymal fraction (BPF) and parenchymal cerebral blood flow (pCBF). Mean decrease in BPF per year was 0.22% total intracranial volume (95% CI: -0.23 to -0.21). Mean decrease in pCBF per year was 0.24 ml/min per 100 ml brain volume (95% CI: -0.29 to -0.20). Using linear mixed models, lower pCBF at baseline was associated with a greater decrease in BPF over time (p = 0.01). Lower baseline BPF, however, was not associated with a greater decrease in pCBF (p = 0.43). These findings indicate that reduced cerebral blood flow is associated with greater progression of brain atrophy and provide further support for a role of cerebral blood flow in the process of neurodegeneration
Low-grade carotid artery stenosis is associated with progression of brain atrophy and cognitive decline. The SMART-MR study
No full textAsymptomatic low-grade carotid artery stenosis (LGCS) is a common finding in patients with manifest arterial disease, however its relationship with brain MRI changes and cognitive decline is unclear. We included 902 patients (58 ± 10 years; 81% male) enrolled in the Second Manifestations of Arterial Disease - Magnetic Resonance (SMART-MR) study without a history of cerebrovascular disease. LGCS was defined as 1-49% stenosis on baseline carotid ultrasound, whereas no LGCS (reference category) was defined as absence of carotid plaque. Brain and white matter hyperintensity (WMH) volumes and cognitive function were measured at baseline and after 4 (n = 480) and 12 years (n = 222) of follow-up. Using linear mixed-effects models, we investigated associations of LGCS with progression of brain atrophy, WMH, and cognitive decline. LGCS was associated with greater progression of global brain atrophy (estimate -0.03; 95%CI, -0.06 to -0.01; p = 0.002), and a greater decline in executive functioning (estimate -0.02; 95%CI, -0.031 to -0.01; p < 0.001) and memory (estimate -0.012; 95%CI, -0.02 to -0.001; p = 0.032), independent of demographics, cardiovascular risk factors, and incident brain infarcts on MRI. No association was observed between LGCS and progression of WMH. Our results indicate that LGCS may represent an early marker of greater future brain atrophy and cognitive decline
The role of cognitive and brain reserve in memory decline and atrophy rate in mid and late-life: The SMART-MR study
No full textOBJECTIVE: Investigate associations of cognitive and brain reserve with trajectories of memory decline in mid-life and late-life, and whether the relationship of memory decline with atrophy differs as a function of reserve. METHODS: Participants were 989 Dutch middle-aged to older adults from the SMART-MR prospective cohort, followed up to 12 years with up to 3 measurements of memory and brain MRI. Education and Dutch National Adult Reading Test (DART) were used as proxies of cognitive reserve, and intracranial volume (ICV) and baseline brain parenchymal fraction (BPF) for brain reserve. Univariate growth curve models analyzed associations of reserve with memory decline, and multiple-group bivariate growth curve models tested the longitudinal brain-memory relationship as a function of reserve. Models were additionally stratified by mid-life and late-life. RESULTS: Higher DART, education, and BPF were related to a slower rate of memory decline, particularly in late-life, but ICV was not. A positive covariance indicated that an individual who undergoes atrophy also undergoes memory decline-this relationship did not differ across cognitive or brain reserve, but was not present in mid-life. Memory declined slower than brain volume, yet rates were more similar in the low DART, education, and BPF groups. DISCUSSION: Higher cognitive (DART, education) and brain reserve (BPF) work protectively in longitudinal memory change. ICV is an inappropriate proxy of brain reserve, failing to show any association with memory performance at baseline or over time. Deconstructing relationships of reserve capacities with longitudinal cognitive and brain outcomes may identify focus areas with potential for intervention
Association of White Matter Hyperintensity Markers on MRI and Long-term Risk of Mortality and Ischemic Stroke: The SMART-MR Study
No full textOBJECTIVE: To determine whether white matter hyperintensity (WMH) markers on MRI are associated with long-term risk of mortality and ischemic stroke. METHODS: We included consecutive patients with manifest arterial disease enrolled in the Second Manifestations of Arterial Disease-Magnetic Resonance (SMART-MR) study. We obtained WMH markers (volume, type, and shape) from brain MRI scans performed at baseline using an automated algorithm. During follow-up, occurrence of death and ischemic stroke was recorded. Using Cox regression, we investigated associations of WMH markers with risk of mortality and ischemic stroke, adjusting for demographics, cardiovascular risk factors, and cerebrovascular disease. RESULTS: We included 999 patients (59 ± 10 years; 79% male) with a median follow-up of 12.5 years (range 0.2-16.0 years). A greater periventricular or confluent WMH volume was independently associated with a greater risk of vascular death (hazard ratio [HR] 1.29, 95% confidence interval [CI] 1.13-1.47) for a 1-unit increase in natural log-transformed WMH volume and ischemic stroke (HR 1.53, 95% CI 1.26-1.86). A confluent WMH type was independently associated with a greater risk of vascular (HR 1.89, 95% CI 1.15-3.11) and nonvascular death (HR 1.65, 95% CI 1.01-2.73) and ischemic stroke (HR 2.83, 95% CI 1.36-5.87). A more irregular shape of periventricular or confluent WMH, as expressed by an increase in concavity index, was independently associated with a greater risk of vascular (HR 1.20, 95% CI 1.05-1.38 per SD increase) and nonvascular death (HR 1.21, 95% CI 1.03-1.42) and ischemic stroke (HR 1.28, 95% CI 1.05-1.55). CONCLUSIONS: WMH volume, type, and shape are associated with long-term risk of mortality and ischemic stroke in patients with manifest arterial disease
Smart Cities and Sustainability Models
No full textIn our age cities are complex systems and we can say systems of systems. Today locality is the result of using information and communication technologies in all departments of our life, but in future all cities must to use smart systems for improve quality of life and on the other hand for sustainable development. The smart systems make daily activities more easily, efficiently and represent a real support for sustainable city development. This paper analysis the sus-tainable development and identified the key elements of future smart cities.Intelligent Cities, Sustainability, Indicators, Regional Development, Intelligent Solution
Smart Grids in the City: Splintering Urbanism in a Smart Urban Future
No full textThis thesis examines how the emergence of smart grids is changing urban development practices and shifting the power relations between the government, private industry and end consumers. The research was undertaken as part of the Customer Led Network Revolution – a UK smart grid research project investigating a shift towards a low carbon economy. This thesis is just one outcome of the project and examines the ways in which smart grids are being produced internationally across a variety of different contexts, conducted with qualitative research with the aim to understand the implications for public responses to new energy technologies. The study first surveyed the development of smart grids projects internationally before selecting the case of the Pecan Street Project in Austin, Texas, to examine the drivers and barriers to the development of smart grids in detail. Drawing on the concepts of splintering urbanism and using the literature of large technical systems, the thesis argues that there are three critical dynamics to the emergence of the smart grid in Austin – the energy discourse that allows a smart grid to emerge; state backing of the project for economic development purposes; and changes in urban planning structures to facilitate smart growth. This study suggests that the growth of smart grids can be tailored to benefit a wide variety of stakeholders, but could “splinter” urban environments with potential risks for rising inequality. The research offers a valuable contribution to how smart grids can be produced in the UK and how they should be managed
Data Study Group Final Report: eGym
No full textData Study Groups are week-long events at The Alan Turing Institute bringing together some of the country’s top talent from data science, artificial intelligence, and wider fields, to analyse real-world data science challenges.
Improved strength training using smart gym equipment data
We were provided with information about users of specialised smart gym equipment and usage data over a period of 2 years. The brief was to explore the data and provide insight into how best to help users improve performance. Of particular interest was the link between training and increased strength (as measured by the machines). Also of interest were longitudinal usage of gym-goers, with the view of aiding adherence to the program, and the creation of a simple performance metric by which user improvement could be measured
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