Cardiovascular health and brain aging : a population-based MRI study

Deterioration of brain structure and cognitive function occurs as individuals reach advanced age. The former can be observed through various markers of cerebral small vessel disease on magnetic resonance imaging (MRI) scans and the later can be assessed by neuropsychological tests and clinical examinations. In addition, maintaining a favorable cardiovascular health (CVH) status may contribute to delaying brain aging. Having a higher cognitive reserve (CR) capacity may contribute to preserving cognitive function even in the presence of brain damage. In this thesis, we aimed to examine the progression and interrelationships of MRI markers of structural brain aging and the association between the progression of these markers and cognitive decline. Furthermore, we aimed to investigate whether maintaining a favorable CVH status would be related to a slower deterioration of brain structure and whether having a higher CR capacity would be associated with a lower risk of cognitive deterioration and death. Data were derived from the population-based Swedish National study on Aging and Care in Kungsholmen from 2001–2004 to 2016–2019 and the MRI sub-study from 2001–2003 to 2007–2010. Study I: This six-year follow-up study showed that the progression rate of cerebral small vessel disease markers including expansion rates of white matter hyperintensities (WMHs) and lateral ventricles, incidence of lacunes, and shrinkage rate of gray matter volume, but not the progression rate of perivascular spaces (PVSs), steadily increased with aging (P < 0.05). The progression rate of regional WMHs was faster in males than in females and in people without a university degree than those with a degree (P < 0.05). In addition, a higher load of microvascular lesions (i.e., WMHs, PVSs, and lacunes) at baseline was related to faster progression of both microvascular lesions (WMHs and lacunes) and gray matter atrophy (P < 0.05). Study II: This follow-up study showed that a greater burden of WMHs at baseline was associated with a faster decline in executive function, letter fluency, perceptual speed, and global cognition over 15 years (P < 0.05), but not in episodic or semantic memory. The faster deterioration in category fluency was linked to greater periventricular WMHs at baseline only in people carrying the APOE-ε4 allele (multivariable-adjusted β-coefficients and 95% confidence interval [CI]: -0.018, -0.031– -0.004). Accelerated decline in perceptual speed over 15 years was linked to a faster increase in deep and periventricular WMHs during the first six years, and accelerated decline in executive function and global cognition was linked to a faster increase in deep WMHs during the first six years (P < 0.05). Study III: This six-year follow-up study showed that compared to the unfavorable global CVH profile, the intermediate-to-favorable profiles were associated with a slower accumulation of WMHs (multivariable-adjusted β-coefficients and 95% CI: -0.019, -0.035– -0.002 and -0.018, - 0.034– -0.001, respectively). Intermediate-to-favorable biological CVH profiles were associated with a slower WMH increase among people aged 60–72 years, but not in those aged 78 years and above. Furthermore, a higher metabolic genetic risk was linked to a faster accumulation of WMHs in people with intermediate-to-favorable global or behavioral CVH profiles, but not in those with favorable CVH profiles (P for both interactions = 0.001). Study IV: This 15-year follow-up study revealed that a higher composite CR score, which was estimated from early-life education, midlife work complexity, late-life leisure activities, and late-life social network, was associated with a reduced risk of transition from normal cognition to cognitive impairment, no dementia (CIND) (multivariable-adjusted hazards ratio and 95% CI: 0.78, 0.72–0.85) and death (0.85, 0.79–0.93) and from CIND to death (0.82, 0.73–0.91), but not from CIND to dementia neither from CIND to normal cognition (P > 0.05). The risk of transitions from normal cognition to CIND or death did not change after controlling for brain aging markers, while the risk of transition from CIND to death became not significant. Furthermore, a higher CR score was associated with a lower risk of transition from CIND to death among people aged 60–72 years (0.65, 0.54–0.77) while not among those aged 78 years and above (0.87, 0.75–1.01) (P for interaction = 0.010). Conclusions: First, the deterioration of brain structure accelerates with advancing age. Cerebral microvascular lesions are associated with accelerated brain atrophy. Second, WMHs are linked to an accelerated decline in multiple cognitive domains except memory. A faster accumulation of WMHs in deep brain regions is associated with an accelerated decline in perceptual speed and executive function. Third, having a favorable CVH profile is associated with a slower progression of structural brain aging attributable to metabolic genetic risk. Finally, having a greater CR capacity might play a crucial role in preserving cognitive health and reducing mortality rate in the prodromal phase of dementia, independent of brain aging markers. The association between higher CR capacity and lower likelihood of transition from CIND to death exists particularly among people in the early stage of older adulthood

Spatial Correlation Analysis on the Resource Allocation Efficiency of Regional Higher Education in China

This analysis may promote the regional development of higher education, resolve problems associated with inadequate resources, and improve efficiency of resource allocation. In this study, we examined the efficiency of resource allocation for higher education in 31 Chinese provinces using data envelopment analysis (DEA); spatial correlation was used concurrently for analytical purposes. Our aims through this study are to promote the optimal allocation of resources and healthy development of higher education

Development of a 3-D Position Sensitive Neutron Detector Based on Organic Scintillators with Double Side SiPM Readout

A 3-D position sensitive neutron detector is being developed based on a plastic scintillator array. A double side SiPM readout is used to determine the depth of interaction (DOI) in each scintillator unit. In the preliminary test, the DOI in a 254 x 6 x 6 mm3 SP101 plastic scintillator is measured at different positions using a collimated Co-60 source. The SiPM (KETEK PM6660) signals are recorded by a 2.5 GS/s digital oscilloscope. The DOI results are calculated using both the amplitude and the temporal information. Position resolutions (FWHM) of 2.5 cm and 6.6 cm are realized, respectively. A detector based on a 2-D array is capable of recording the 3-D position information of the incident neutron. The 3-D detector is to be used together with a neutron time projection chamber as a directional fast neutron detector. According to the simulation results, the angular resolution (8 degree FWHM) is much better than that of a typical neutron scatter camera.Comment: 7 pages, 7 figures, submitted to IEEE NSS MIC 201

A systematic review on sustainability assessment of internal combustion engines

Internal combustion engines (ICEs) have served as the primary powertrain for mobile sources since the 1890s and also recognized as significant contributors to CO2 emissions in the transportation sector. In order to achieve "carbon neutrality" for transportation sectors, ICE vehicles (ICEVs) are facing substantial challenges in meeting CO2 regulations and intense competition from battery electric vehicles and fuel cell vehicles. Consequently, new technologies of ICEs are continually emerging to enhance competitiveness in reducing environmental impacts. However, the limited studies on the life cycle assessment (LCA) of ICEs make it difficult to evaluate the actual contributions of the emerging technologies from a life cycle perspective. Conducting a systematic review of ICEs LCA studies could identify weaknesses and gaps in these studies for new scenarios. Therefore, this article presents the first systematic review of the LCA of ICEs to provide an overview of the current state of knowledge. A total of 87 life cycle assessment studies between 2017 and 2023 using the Scopus database were identified after searching for the keywords "Sustainability assessment" OR "Life cycle assessment" AND "Internal combustion engine*" OR "ICE*" and carefully screening, and then classified and analyzed by six aspects including sustainability indicators, life cycle phases, life cycle inventories, ICE technologies (including alternative fuels), types of mobile sources and powertrain systems. It is concluded that there are quite limited studies solely focusing on LCA of ICEs, and the LCA assessment lacks consideration of: 1. environmental pollution, human health and socio-economic aspects, 2. fuel production process and maintenance &amp; repair phase, 3. small and developing countries, 4. the emerging ICE technologies and zero carbon/carbon-neutral fuels, 5. large and high-power mobile sources and heavy-duty hybrid technologies