Aging causes deterioration in cognitive performance in healthy adults. Different diagnostic terms have been used to discribe the cognitive decline associated with aging.This article reviews the clinical characteristic...Aging causes deterioration in cognitive performance in healthy adults. Different diagnostic terms have been used to discribe the cognitive decline associated with aging.This article reviews the clinical characteristics of age-associated cognitive impairment(AAMI) and other related concepts.展开更多
During the past few years, many researchers have demonstrated the importance of the age-related changes in spontaneous electroencephalography. However, very little research on of the event-related responses of oscilla...During the past few years, many researchers have demonstrated the importance of the age-related changes in spontaneous electroencephalography. However, very little research on of the event-related responses of oscillations connections has been used to examine the changes during normal aging. The aim of the present study was to investigate age-related changes of task-related brain oscillations, which include spectral power and omega-complexity. We hypothesized that the power and omega-complexity of the brain are affected by age-related changes, which could be observed in this study. The samples included young and healthy elderly groups. Compared to young participants, elderly participants were found to have increased power in anterior area and decreased power in posterior area, and have shown a decreased power in the alpha-1 (7 - 10 Hz) and alpha-2 (10 - 13 Hz) bands and an increased power in the delta (1 - 4 Hz) band. Elderly participants were found to have increased omega-complexity in the anterior and posterior brain areas, and have shown an increased omega-complexity in the alpha-2, beta-1 (13 - 18 Hz), and beta-2 (18 - 30 Hz) bands. The findings in this study suggest that power and omega-complexity changes in task-specific neural activity may potentially be used to assess age-related decline in the brain.展开更多
Having a parent affected by late-onset Alzheimer’s disease (AD) is a major risk factor for cognitively normal (NL) individuals. This study explores the potential of PET with 18F-FDG and the amyloid-β (Aβ) tracer 11...Having a parent affected by late-onset Alzheimer’s disease (AD) is a major risk factor for cognitively normal (NL) individuals. This study explores the potential of PET with 18F-FDG and the amyloid-β (Aβ) tracer 11C-Pittsburgh Compound B (PiB) for detection of individual risk in NL adults with AD-parents. Methods: FDG- and PiB-PET was performed in 119 young to late-middle aged NL individuals including 80 NL with positive family history of AD (FH+) and 39 NL with negative family history of any dementia (FH-). The FH+ group included 50 subjects with maternal (FHm) and 30 with paternal family history (FHp). Individual FDG and PiB scans were Z scored on a voxel-wise basis relative to modality-specific reference databases using automated procedures and rated as positive or negative (+/-) for AD-typical abnormalities using predefined criteria. To determine the effect of age, the cohort was separated into younger (49 ± 9 y) and older (68 ± 5 y) groups relative to the median age (60 y). Results: Among individuals of age >60 y, as compared to controls, NL FH+ showed a higher frequency of FDG+ scans vs. FH- (53% vs. 6% p < 0.003), and a trend for PiB+ scans (27% vs. 11%;p = 0.19). This effect was observed for both FHm and FHp groups. Among individuals of age ≤60 y, NL FHm showed a higher frequency of FDG+ scans (29%) compared to FH- (5%, p = 0.04) and a trend compared to FHp (11%) (p = 0.07), while the distribution of PiB+ scans was not different between groups. In both age cohorts, FDG+ scans were more frequent than PiB+ scans among NL FH+, especially FHm (p < 0.03). FDG-PET was a significant predictor of FH+ status. Classification according to PiB status was significantly less successful. Conclusions: Automated analysis of FDG- and PiB-PET demonstrates higher rates of abnormalities in at-risk FH+ vs FH-subjects, indicating potentially ongoing early AD-pathology in this population. The frequency of metabolic abnormalities was higher than that of Aβ pathology in the younger cohort, suggesting that neuronal dysfunc展开更多
The tribological behavior of aged Al-Sn-Cu alloy rubbed in the presence of lubricant over a range of sliding velocities and normal loads was investigated. The results showed that peak-aged （PA） alloy had a better tr...The tribological behavior of aged Al-Sn-Cu alloy rubbed in the presence of lubricant over a range of sliding velocities and normal loads was investigated. The results showed that peak-aged （PA） alloy had a better tribological behavior than under-aged （UA） and over-aged （OA） alloys, which could be attributed to the optimized strength-ductility matching and a better hardness under PA condition. Wear rate and friction coefficient showed great sensitivity to applied sliding velocity and normal load. The wear rate and friction coefficient of the alloy exhibited a reduction trend with the increase in sliding velocity. The low wear rate and friction coefficient of alloy at high velocities were due to the effectively protected film and homogeneous Sn on surface. However, an increase in normal load led to an obvious increment in wear rate. The friction coefficient exhibited a fluctuant trend with the increase of normal loads. The seriously destroyed film and abraded Sn resulted in poor tribological behavior at high normal loads. The Sn particles and lubricant film which includes low shear interfacial lubricating layer and oxide tribolayer are the key to the tribological behavior of Al-Sn-Cu alloy.展开更多
Hutchinson-Gilford progeria syndrome(HGPS,OMIM176670)is an extremely rare,sporadic genetic syndrome with a reported prevalence of one in4-8million children worldwide.At April2012,the total number of known living child...Hutchinson-Gilford progeria syndrome(HGPS,OMIM176670)is an extremely rare,sporadic genetic syndrome with a reported prevalence of one in4-8million children worldwide.At April2012,the total number of known living children with HGPS was89worldwide,according to data from the Progeria Research Foundation.展开更多
文摘Aging causes deterioration in cognitive performance in healthy adults. Different diagnostic terms have been used to discribe the cognitive decline associated with aging.This article reviews the clinical characteristics of age-associated cognitive impairment(AAMI) and other related concepts.
文摘During the past few years, many researchers have demonstrated the importance of the age-related changes in spontaneous electroencephalography. However, very little research on of the event-related responses of oscillations connections has been used to examine the changes during normal aging. The aim of the present study was to investigate age-related changes of task-related brain oscillations, which include spectral power and omega-complexity. We hypothesized that the power and omega-complexity of the brain are affected by age-related changes, which could be observed in this study. The samples included young and healthy elderly groups. Compared to young participants, elderly participants were found to have increased power in anterior area and decreased power in posterior area, and have shown a decreased power in the alpha-1 (7 - 10 Hz) and alpha-2 (10 - 13 Hz) bands and an increased power in the delta (1 - 4 Hz) band. Elderly participants were found to have increased omega-complexity in the anterior and posterior brain areas, and have shown an increased omega-complexity in the alpha-2, beta-1 (13 - 18 Hz), and beta-2 (18 - 30 Hz) bands. The findings in this study suggest that power and omega-complexity changes in task-specific neural activity may potentially be used to assess age-related decline in the brain.
文摘Having a parent affected by late-onset Alzheimer’s disease (AD) is a major risk factor for cognitively normal (NL) individuals. This study explores the potential of PET with 18F-FDG and the amyloid-β (Aβ) tracer 11C-Pittsburgh Compound B (PiB) for detection of individual risk in NL adults with AD-parents. Methods: FDG- and PiB-PET was performed in 119 young to late-middle aged NL individuals including 80 NL with positive family history of AD (FH+) and 39 NL with negative family history of any dementia (FH-). The FH+ group included 50 subjects with maternal (FHm) and 30 with paternal family history (FHp). Individual FDG and PiB scans were Z scored on a voxel-wise basis relative to modality-specific reference databases using automated procedures and rated as positive or negative (+/-) for AD-typical abnormalities using predefined criteria. To determine the effect of age, the cohort was separated into younger (49 ± 9 y) and older (68 ± 5 y) groups relative to the median age (60 y). Results: Among individuals of age >60 y, as compared to controls, NL FH+ showed a higher frequency of FDG+ scans vs. FH- (53% vs. 6% p < 0.003), and a trend for PiB+ scans (27% vs. 11%;p = 0.19). This effect was observed for both FHm and FHp groups. Among individuals of age ≤60 y, NL FHm showed a higher frequency of FDG+ scans (29%) compared to FH- (5%, p = 0.04) and a trend compared to FHp (11%) (p = 0.07), while the distribution of PiB+ scans was not different between groups. In both age cohorts, FDG+ scans were more frequent than PiB+ scans among NL FH+, especially FHm (p < 0.03). FDG-PET was a significant predictor of FH+ status. Classification according to PiB status was significantly less successful. Conclusions: Automated analysis of FDG- and PiB-PET demonstrates higher rates of abnormalities in at-risk FH+ vs FH-subjects, indicating potentially ongoing early AD-pathology in this population. The frequency of metabolic abnormalities was higher than that of Aβ pathology in the younger cohort, suggesting that neuronal dysfunc
基金Project(2013AH100055)supported by the Special Foundation for Science and Technology Innovation of Foshan,China
文摘The tribological behavior of aged Al-Sn-Cu alloy rubbed in the presence of lubricant over a range of sliding velocities and normal loads was investigated. The results showed that peak-aged （PA） alloy had a better tribological behavior than under-aged （UA） and over-aged （OA） alloys, which could be attributed to the optimized strength-ductility matching and a better hardness under PA condition. Wear rate and friction coefficient showed great sensitivity to applied sliding velocity and normal load. The wear rate and friction coefficient of the alloy exhibited a reduction trend with the increase in sliding velocity. The low wear rate and friction coefficient of alloy at high velocities were due to the effectively protected film and homogeneous Sn on surface. However, an increase in normal load led to an obvious increment in wear rate. The friction coefficient exhibited a fluctuant trend with the increase of normal loads. The seriously destroyed film and abraded Sn resulted in poor tribological behavior at high normal loads. The Sn particles and lubricant film which includes low shear interfacial lubricating layer and oxide tribolayer are the key to the tribological behavior of Al-Sn-Cu alloy.
文摘Hutchinson-Gilford progeria syndrome(HGPS,OMIM176670)is an extremely rare,sporadic genetic syndrome with a reported prevalence of one in4-8million children worldwide.At April2012,the total number of known living children with HGPS was89worldwide,according to data from the Progeria Research Foundation.
