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1.
Article in English | MEDLINE | ID: mdl-38943223

ABSTRACT

Se-free n-type (Bi,Sb)2Te3 thermoelectric materials, outperforming traditional n-type Bi2(Te,Se)3, emerge as a compelling candidate for practical applications of recovering low-grade waste heat. A 100% improvement in the maximum ZT of n-type Bi1.7Sb0.3Te3 is demonstrated by using melt-spinning and excess Te-assisted transient liquid phase sintering (LPS). Te-rich sintering promotes the formation of intrinsic defects (TeBi), elevating the carrier concentration and enhancing the electrical conductivity. Melt-spinning with excess Te fine-tunes the electronic band, resulting in a high power-factor of 0.35 × 10-3 W·m-1 K-2 at 300 K. Rapid volume change during sintering induces the formation of dislocation networks, significantly suppressing the lattice thermal conductivity (0.4 W·m-1 K-1). The developed n-type legs achieve a high maximum ZT of 1.0 at 450 K resulting in a 70% improvement in the output power of the thermoelectric device (7.7 W at a temperature difference of 250 K). This work highlights the synergy between melt-spinning and transient LPS, advancing the tailored control of both electronic and thermal properties in thermoelectric technology.

2.
J Autism Dev Disord ; 2024 May 26.
Article in English | MEDLINE | ID: mdl-38796794

ABSTRACT

This study sought to understand the wide variability in vocabulary development among autistic children by testing potential social and linguistic correlates of vocabulary size. The correlation between overlapping vocalization (i.e., an aspect of social interaction relevant to accessing input for vocabulary acquisition) and phonological memory (i.e., retaining linguistic sound sequences) with vocabulary size were examined in 22 autistic children (3 to 11 years old) engaged in a structured nonword repetition task. Overlapping vocalization and phonological memory were correlated with vocabulary size. Overlapping vocalization remained a significant predictor of receptive and expressive vocabulary size when controlling phonological memory and nonverbal cognition. Both social and linguistic factors were associated with receptive and expressive vocabulary size in autistic children engaged in a structured task.

3.
Heliyon ; 10(5): e26307, 2024 Mar 15.
Article in English | MEDLINE | ID: mdl-38468974

ABSTRACT

Recently, with the development of non-invasive human health monitoring technology including wearable devices, a flexible sensor that monitors 'human sound and movement signals' such as human voice and muscle movement is attracting attention. In this experiment, electrospun nanofibers were mixed with highly conductive nanoparticles and coated with polyaniline to detect the patient's electrical signals. Due to the high piezoelectric effect, nanofiber-based sensors do not require charging through a separate battery, so they can be used as self-powered devices. In addition, the LCR meter test confirmed that the sensor has a high capacitance due to its high conductivity and high sensitivity to electrical signals. The sensor produced in this study can visually estimate the electrical signal of the actual human body through real-time comparison with electromyography (EMG) measuring equipment, and it was confirmed that the error is small. This sensor is expected to be widely used in the medical field, from simple sound and movement signals to disease monitoring.

4.
ACS Appl Mater Interfaces ; 14(10): 12797-12811, 2022 Mar 16.
Article in English | MEDLINE | ID: mdl-35234455

ABSTRACT

A vital objective in the wetting of Au deposited on chemically heterogeneous oxides is to synthesize a completely continuous, highly crystalline, ultrathin-layered geometry with minimized electrical and optical losses. However, no effective solution has been proposed for synthesizing an ideal Au-layered structure. This study presents evidence for the effectiveness of atomic oxygen-mediated growth of such an ideal Au layer by improving Au wetting on ZnO substrates with a substantial reduction in free energy. The unexpected outcome of the atomic oxygen-mediated Au growth can be attributed to the unconventional segregation and incorporation of atomic oxygen along the outermost boundaries of Au nanostructures evolving in the clustering and layering stages. Moreover, the experimental and numerical investigations revealed the spontaneous migration of atomic oxygen from an interstitial oxygen surplus ZnO bulk to the Au-ZnO interface, as well as the segregation (float-out) of the atomic oxygen toward the top Au surfaces. Thus, the implementation of a 4-nm-thick, two-dimensional, quasi-single-crystalline Au layer with a nearly complete crystalline realignment at a mild temperature (570 K) enabled exceptional optoelectrical performance with record-low resistivity (<7.5 × 10-8 Ω·m) and minimal optical loss (∼3.5%) at a wavelength of 700 nm.

5.
Nanoscale ; 12(3): 1749-1758, 2020 Jan 23.
Article in English | MEDLINE | ID: mdl-31895376

ABSTRACT

Artificially designing the crystal orientation and facets of noble metal nanoparticles is important to realize unique chemical and physical features that are very different from those of noble metals in bulk geometries. However, relative to their counterparts synthesized in wet-chemical processes, vapor-depositing noble metal nanoparticles with the desired crystallographic features while avoiding any notable impurities is quite challenging because this task requires breaking away from the thermodynamically favorable geometry of nanoparticles. We used plasma-generated N atoms as a surface-active agent, a so-called surfactant, to control the structural development of Ag nanoparticles supported on a chemically heterogeneous ZnO substrate. The N-surfactant-facilitated sputter deposition provided strong selectivity for crystalline orientation and facets, leading to a highly flattened nanoparticle shape that clearly deviated from the energetically favorable spherical polyhedra, due to the drastic decreases in the surface free energies of Ag nanoparticles in the presence of the N surfactant. The Ag nanoparticles successively developed a nearly unidirectional (111) orientation aligned by stimulating the crystalline coupling of Ag along the orientation of the ZnO substrate. The experimental and simulation results not only offer new insights into the advantages of N as a surfactant for the orientation and shape-controlled synthesis of Ag nanoparticles via sputter deposition but also provide the first solid evidence validating that immiscible, nonresidual gaseous surfactants can be used in the vapor deposition processes of noble metal nanoparticles to manipulate their surface free energies.

6.
ACS Appl Mater Interfaces ; 10(32): 27510-27520, 2018 Aug 15.
Article in English | MEDLINE | ID: mdl-30028116

ABSTRACT

Improving the wetting ability of Ag on chemically heterogeneous oxides is technically important to fabricate ultrathin, continuous films that would facilitate the minimization of optical and electrical losses to develop qualified transparent Ag film electrodes in the state-of-the-art optoelectronic devices. This goal has yet to be attained, however, because conventional techniques to improve wetting of Ag based on heterogeneous metallic wetting layers are restricted by serious optical losses from wetting layers. Herein, we report on a simple and effective technique based on the partial oxidation of Ag nanoclusters in the early stages of Ag growth. This promotes the rapid evolution of the subsequently deposited pure Ag into a completely continuous layer on the ZnO substrate, as verified by experimental and numerical evidence. The improvement in the Ag wetting ability allows the development of a highly transparent, ultrathin (6 nm) Ag continuous film, exhibiting an average optical transmittance of 94% in the spectral range 400-800 nm and a sheet resistance of 12.5 Ω sq-1, which would be well-suited for application to an efficient front window electrode for flexible solar cell devices fabricated on polymer substrates.


Subject(s)
Silver/chemistry , Electric Conductivity , Electricity , Electrodes , Oxides
7.
ACS Appl Mater Interfaces ; 9(44): 38695-38705, 2017 Nov 08.
Article in English | MEDLINE | ID: mdl-29039201

ABSTRACT

The development of highly efficient flexible transparent electrodes (FTEs) supported on polymer substrates is of great importance to the realization of portable and bendable photovoltaic devices. Highly conductive, low-cost Cu has attracted attention as a promising alternative for replacing expensive indium tin oxide (ITO) and Ag. However, highly efficient, Cu-based FTEs are currently unavailable because of the absence of an efficient means of attaining an atomically thin, completely continuous Cu film that simultaneously exhibits enhanced optical transmittance and electrical conductivity. Here, strong two-dimensional (2D) epitaxy of Cu on ZnO is reported by applying an atomically thin (around 1 nm) oxygen-doped Cu wetting layer. Analyses of transmission electron microscopy images and X-ray diffraction patterns, combined with first-principles density functional theory calculations, reveal that the reduction in the surface and interface free energies of the wetting layers with a trace amount (1-2 atom %) of oxygen are largely responsible for the two-dimensional epitaxial growth of the Cu on ZnO. The ultrathin 2D Cu layer, embedded between ZnO films, exhibits a highly desirable optical transmittance of over 85% in a wavelength range of 400-800 nm and a sheet resistance of 11 Ω sq-1. The validity of this innovative approach is verified with a Cu-based FTE that contributes to the light-to-electron conversion efficiency of a flexible organic solar cell that incorporates the transparent electrode (7.7%), which far surpasses that of a solar cell with conventional ITO (6.4%).

8.
Sci Rep ; 7(1): 12195, 2017 09 22.
Article in English | MEDLINE | ID: mdl-28939835

ABSTRACT

Cast-Al alloys that include a high amount of the second element in their matrix have comparatively high strength but low ductility because of the high volume fraction of strengthening phases or undesirable inclusions. Al-Zn alloys that have more than 30 wt% Zn have a tensile strength below 300 MPa, with elongation under 5% in the as-cast state. However, we found that after substitution of 2% Zn by Cu, the tensile strength of as-cast Al-Zn-Cu alloys was 25% higher and ductility was four times higher than for the corresponding Al-35% Zn alloy. Additionally, for the Al-43% Zn alloy with 2% Cu after 1 h solution treatment at 400 °C and water quenching, the tensile strength unexpectedly reached values close to 600 MPa. For the Al-33% Zn alloy with 2% Cu, the tensile strength was 500 MPa with 8% ductility. The unusual trends of the mechanical properties of Al-Zn alloys with Cu addition observed during processing from casting to the subsequent solution treatment were attributed to the precipitation of Zn in the Al matrix. The interface energy between the Zn particles and the Al matrix decreased when using a solution of Cu in Zn.

9.
J Am Geriatr Soc ; 59(9): 1628-35, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21883111

ABSTRACT

OBJECTIVES: To investigate the nature of frontal dysfunction associated with chronic kidney disease (CKD) in people without stroke or depressive disorders. DESIGN: Cross-sectional. SETTING: Community based. PARTICIPANTS: Five hundred twenty-nine community-dwelling participants. MEASUREMENTS: Participants with CKD were classified into one of three diagnostic groups based on their estimated glomerular filtration rate (eGFR): normal (≥ 60.0 mL/min per 1.73 m(2)), mild CKD (45.0-59.9 mL/min per 1.73 m(2)), or moderate to severe CKD (<45.0 mL/min per 1.73 m(2)). Cognitive function was assessed using the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychological Assessment Battery, lexical fluency, digit span test, and the 64-card Wisconsin Card Sorting Test. RESULTS: Perseverative responses and perseverative errors were significantly more prevalent in the group with moderate to severe CKD than in those without CKD and those with mild CKD. The mean number of perseverative responses was 28.6 ± 16.9 in participants with moderate to severe CKD, 19.0 ± 11.4 in those with mild CKD, and 17.1 ± 10.6 in those without CKD (P < .001, ANCOVA). The mean number of perseverative errors was 23.1 ± 12.3 in participants with moderate to severe CKD, 16.2 ± 8.3 in those with mild CKD, and 14.8 ± 7.8 in those without CKD (P < .001, analysis of covariance). The odds ratios in the fully adjusted model for the presence of moderate to severe CKD for perseverative responses and perseverative errors were 4.82 (95% confidence interval (CI) = 2.14-10.85, P < .001) and 5.01 (95% CI = 2.22-11.28, P<.001), respectively. CONCLUSION: Frontal dysfunction, particularly perseverative errors and responses, was associated with moderate to severe CKD in the population studied.


Subject(s)
Cognition Disorders/etiology , Executive Function , Kidney Diseases/psychology , Aged , Aged, 80 and over , Chronic Disease , Cross-Sectional Studies , Female , Frontal Lobe , Humans , Kidney Diseases/complications , Kidney Diseases/therapy , Male , Renal Dialysis
10.
Alzheimer Dis Assoc Disord ; 25(3): 225-9, 2011.
Article in English | MEDLINE | ID: mdl-21285856

ABSTRACT

The criterion on functional activity in the revised diagnostic criteria for mild cognitive impairment (MCI) seems to be conceptually and operationally problematic.We investigated the predictive validity for dementia of this criterion in 140 patients with MCI who participated in the baseline study of the Korean Longitudinal Study on Health and Aging and completed 18-month follow-up evaluation (mean duration of follow-up, 1.57±0.24 y). Annual conversion rates to dementia were compared between the patients who fulfilled the criterion on functional activity and those who did not. Annual conversion rates to dementia of the patients who fulfilled the criterion on functional activity was 4.76%, whereas that of the patients with MCI who did not was 33.07%, indicating that the criterion on functional activity was a significant negative predictor of dementia (odds ratio=0.12). Re-revision of the criterion on functional activity may be warranted to solve its conceptual and operational ambiguities.


Subject(s)
Activities of Daily Living , Cognitive Dysfunction/diagnosis , Geriatric Assessment/methods , Neuropsychological Tests , Aged , Aged, 80 and over , Alzheimer Disease/diagnosis , Cohort Studies , Dementia/diagnosis , Disease Progression , Humans , Longitudinal Studies , Predictive Value of Tests , Psychiatric Status Rating Scales
11.
J Am Chem Soc ; 133(4): 976-85, 2011 Feb 02.
Article in English | MEDLINE | ID: mdl-21175203

ABSTRACT

The allyl moiety of the immunosuppressive agent FK506 is structurally unique among polyketides and critical for its potent biological activity. Here, we detail the biosynthetic pathway to allylmalonyl-coenzyme A (CoA), from which the FK506 allyl group is derived, based on a comprehensive chemical, biochemical, and genetic interrogation of three FK506 gene clusters. A discrete polyketide synthase (PKS) with noncanonical domain architecture presumably in coordination with the fatty acid synthase pathway of the host catalyzes a multistep enzymatic reaction to allylmalonyl-CoA via trans-2-pentenyl-acyl carrier protein. Characterization of this discrete pathway facilitated the engineered biosynthesis of novel allyl group-modified FK506 analogues, 36-fluoro-FK520 and 36-methyl-FK506, the latter of which exhibits improved neurite outgrowth activity. This unique feature of FK506 biosynthesis, in which a dedicated PKS provides an atypical extender unit for the main modular PKS, illuminates a new strategy for the combinatorial biosynthesis of designer macrolide scaffolds as well as FK506 analogues.


Subject(s)
Malonyl Coenzyme A/biosynthesis , Malonyl Coenzyme A/chemistry , Polyketide Synthases/metabolism , Sequence Deletion , Tacrolimus/analogs & derivatives , Tacrolimus/metabolism , Malonyl Coenzyme A/metabolism , Multigene Family , Streptomyces/enzymology , Streptomyces/genetics , Streptomyces/metabolism
12.
J Am Chem Soc ; 132(49): 17447-51, 2010 Dec 15.
Article in English | MEDLINE | ID: mdl-21087015

ABSTRACT

Single-crystalline free-standing hexagonal Fe(1.3)Ge nanowires (NWs) are synthesized for the first time using a chemical vapor transport process without using any catalyst. Interestingly, Fe(1.3)Ge NWs are found to be ferromagnetic at room temperature, while bulk Fe(1.3)Ge has the lower critical temperature of 200 K. We perform first-principles density functional calculations and suggest that the observed strong ferromagnetism is attributed to the reduced distances between Fe atoms, increased number of Fe-Fe bonds, and the enhanced Fe magnetic moments. Both experimental and theoretical studies show that the magnetic moments are enhanced in the NWs, as compared to bulk Fe(1.3)Ge. We also modulate the composition ratio of as-grown iron germanide NWs by adjusting experimental conditions. It is shown that uniaxial strain on the hexagonal plane also enhances the ferromagnetic stability.

13.
J Affect Disord ; 125(1-3): 234-40, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20188423

ABSTRACT

OBJECTIVE: We investigated the prevalence, risk factors and impact of major depressive disorder (MDD) and minor depressive disorder (MnDD) in a randomly selected community-dwelling Korean elderly population. METHOD: This study was conducted as a part of the Korean Longitudinal Study on Health and Aging (KLoSHA). A study population of 1118 Korean elders was randomly sampled from residents of Seongnam, Korea aged 65 years or older. Standardized face-to-face interviews and neurological and physical examinations were conducted on 714 respondents using the Korean version of Mini International Neuropsychiatric Interview. MDD was diagnosed according to the DSM-IV criteria, and MnDD according to research criteria proposed in Appendix B of the DSM-IV criteria. RESULTS: Age-, gender- and education-standardized prevalence rates in Korean elders aged 65 years or older were estimated as 5.37% (95% CI=3.72-7.03) for MDD, 5.52% (95% CI=3.84-7.19) for MnDD, and 10.89% (95% CI=8.60-13.17) for overall late-life depression (LLD). A prior MDD episode (OR=3.07, 95% CI=1.38-6.82 in MDD, OR=3.44, 95% CI=1.49-7.94 in MnDD), female gender (OR=3.55, 95% CI=1.53-8.24 in MDD, OR=2.68, 95% CI=1.19-6.04 in MnDD) and history of stroke or TIA (OR=3.45, 95% CI=1.62-7.35 in MDD, OR=2.95, 95% CI=1.34-6.52 in MnDD) were associated with the risks of both MDD and MnDD. Lack of formal education (OR=2.75, 95% CI=1.30-5.85) and low income (OR=2.83, 95% CI=1.02-7.88) were associated with the risk of MDD only. Quality of life (QOL) of the MDD and MnDD patients was worse than that of non-depressed elders (P<0.001, ANOVA). CONCLUSION: MnDD was as prevalent as MDD in Korean elders and impacted QOL as MDD did. MnDD patients may increase in the future with accelerated population aging and westernization of lifestyle in Korea.


Subject(s)
Asian People/psychology , Depressive Disorder, Major/ethnology , Depressive Disorder, Major/epidemiology , Depressive Disorder/ethnology , Depressive Disorder/epidemiology , Age Factors , Aged , Aged, 80 and over , Cost of Illness , Cross-Sectional Studies , Depressive Disorder/diagnosis , Depressive Disorder/psychology , Depressive Disorder, Major/diagnosis , Depressive Disorder, Major/psychology , Female , Health Surveys , Humans , Interview, Psychological , Longitudinal Studies , Male , Quality of Life/psychology , Republic of Korea
14.
J Sleep Res ; 19(1 Pt 1): 87-92, 2010 Mar.
Article in English | MEDLINE | ID: mdl-19686313

ABSTRACT

The aim of this study was to determine the prevalence, neuropsychiatric comorbidities, iron metabolism and potential risk factors of restless legs syndrome (RLS) in the elderly Korean population. As a community-based epidemiological study, a simple random sample of 1118 was drawn from a roster of 61 730 adult individuals aged 65 years and older and 714 participated. The diagnosis of RLS was established in face-to-face interviews using the four minimal diagnostic criteria for RLS recommended by National Institute of Health. Depressive symptoms, nocturnal sleep disturbances, daytime sleepiness and quality of life were evaluated. Laboratory tests of iron metabolism, markers of inflammation, renal and endocrine function, hormones and vitamins were performed. A total of 59 patients (42 women and 17 men) were diagnosed as RLS with a prevalence of 8.3% (95% confidence interval: 6.2-10.3%), with an almost twofold higher prevalence in women (10.2%) than in men (5.7%). Depression was more prevalent among the subjects with RLS than without RLS and poor nocturnal sleep and quality of life were also observed in subjects with RLS. Daytime sleepiness was observed in 32.8% of subjects with RLS. No significant differences were found in iron metabolism or other risk factors between the subjects with and without RLS. The prevalence of RLS in the Korean elderly population was comparable with that in the Caucasian population. RLS had undesirable effects on mood, sleep quality and general wellbeing of elderly individuals.


Subject(s)
Aging/physiology , Anemia, Iron-Deficiency/epidemiology , Asian People/statistics & numerical data , Health Status , Restless Legs Syndrome/epidemiology , Aged , Comorbidity , Endocrine Glands/physiopathology , Female , Follow-Up Studies , Humans , Kidney Diseases/epidemiology , Male , Prevalence , Quality of Life/psychology , Republic of Korea/epidemiology , Restless Legs Syndrome/diagnosis , Risk Factors , Severity of Illness Index
15.
Dement Geriatr Cogn Disord ; 28(1): 23-9, 2009.
Article in English | MEDLINE | ID: mdl-19609083

ABSTRACT

AIMS: We investigated the influence of varying applications of diagnostic criteria on the prevalence of mild cognitive impairment (MCI) in community-dwelling Korean elders. METHODS: A study population of 1,118 Korean elders was randomly sampled from the residents aged 65 years or older living in Seongnam, Korea. Standardized face-to-face interviews, with neurological and physical examinations, were conducted with 714 respondents. Cognitive function was evaluated using the Korean version of the CERAD Neuropsychological Assessment Battery, digit span test, and lexical fluency test. Activities of daily living were evaluated using the Blessed Dementia Scale in the CERAD Clinical Assessment Battery (Korean version). Using variable sets of operational diagnostic criteria, the prevalence of MCI was estimated. RESULTS: Age- and gender-standardized prevalence estimates according to the Petersen criteria were 28.6% (95% CI = 25.3-31.9) for overall MCI, 17.0% (95% CI = 14.3-19.8) for amnestic MCI, and 11.5% (95% CI = 9.2-13.9) for non-amnestic MCI. However, the estimated prevalence of MCI varied widely (8.3-27.6%) according to the applied operational diagnostic criteria. The proportion of MCI subtypes also varied considerably according to the number and types of applied neuropsychological tests. CONCLUSIONS: Variable implementation of MCI diagnostic criteria may significantly complicate the homogeneity of this condition.


Subject(s)
Aging/physiology , Cognition Disorders/diagnosis , Cognition Disorders/psychology , Health Surveys , Aged , Alzheimer Disease/diagnosis , Alzheimer Disease/psychology , Cognition Disorders/classification , Disease Progression , Female , Humans , Korea , Longitudinal Studies , Male , Neuropsychological Tests , Sex Characteristics
16.
Int J Geriatr Psychiatry ; 24(12): 1420-8, 2009 Dec.
Article in English | MEDLINE | ID: mdl-19606424

ABSTRACT

OBJECTIVES: We investigated the prevalence and comorbidities of problem drinking in community-dwelling elders living in Korea. METHODS: Structured face-to-face diagnostic interviews were administered to the 714 Korean elders randomly sampled from Seongnam, Korea. According to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria and the Alcohol Use Disorders Identification Test (AUDIT) scores, the participants were categorized into one of six diagnostic groups: lifetime abstainer, ex-drinker, social drinking, at-risk drinking, alcohol abuse, and alcohol dependence. RESULTS: Prevalence rates of social drinking, at-risk drinking, alcohol abuse, and alcohol dependence were estimated to be 13.60%, 5.42%, 2.28%, and 2.92%, respectively. Problem drinking was associated with increased risks of smoking (OR = 3.52), whereas social drinking was associated with decreased risks of stroke (OR = 0.27) and depression (OR = 0.49). CONCLUSIONS: Problem drinking was common particularly in men and associated with smoking. Social drinking was associated with the lower risks of stroke and depression.


Subject(s)
Alcohol-Related Disorders/epidemiology , Alcohol-Related Disorders/psychology , Depressive Disorder/epidemiology , Stroke/epidemiology , Age Factors , Aged , Aged, 80 and over , Aging/physiology , Alcohol Drinking/epidemiology , Comorbidity , Depressive Disorder/psychology , Female , Humans , Korea/epidemiology , Male , Middle Aged , Neuropsychological Tests , Prevalence , Sex Factors , Smoking/epidemiology , Surveys and Questionnaires
17.
Dement Geriatr Cogn Disord ; 27(4): 310-7, 2009.
Article in English | MEDLINE | ID: mdl-19252402

ABSTRACT

AIM: We aimed to evaluate the psychometric properties of the Subjective Memory Complaints Questionnaire (SMCQ). METHODS: The reliability of the SMCQ was evaluated by testing its internal consistency and test-retest reliability. Pearson correlation analyses were performed to assess the concurrent validity. Confirmatory factor analysis was used to evaluate the construct validity. Diagnostic ability for dementia was tested with receiver operator characteristic curve analyses. RESULTS: Cronbach's alpha coefficient and intraclass correlation coefficients of the SMCQ were 0.864 and 0.828 (p < 0.001), respectively. The SMCQ scores were significantly correlated with the scores on Camdex Memory Complaint Questionnaire, Seoul Informant Report Questionnaire for Dementia and cognitive tests from the CERAD (Consortium to Establish a Registry for Alzheimer's Disease) neuropsychological test battery (p < 0.01). The results of confirmatory factor analyses confirmed that the SMCQ consisted of subjective memory complaints (SMC) for general memory and for everyday memory. The SMCQ score discriminated well between nondemented elderly without dementia and those with dementia (p < 0.01). The area under the curve value of the SMCQ was 0.84, indicating that it had high diagnostic ability. CONCLUSION: The SMCQ was found to be a brief, reliable and valid questionnaire for evaluating SMC. It might be useful for evaluating the cognition of elderly subjects when reliable informants are not available.


Subject(s)
Memory Disorders/diagnosis , Memory Disorders/psychology , Surveys and Questionnaires , Aged , Dementia/diagnosis , Dementia/psychology , Factor Analysis, Statistical , Female , Humans , Male , Neuropsychological Tests , Psychiatric Status Rating Scales , Psychometrics , Psychomotor Performance/physiology , ROC Curve , Reproducibility of Results
18.
Stroke ; 40(3): 966-9, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19150874

ABSTRACT

BACKGROUND AND PURPOSE: Studies on the epidemiology of stroke and transient ischemic attack (TIA) are very limited in Asian elderly populations. We investigate the prevalence, risk factors, and neuropsychiatric comorbidities of stroke and TIA in community-dwelling Korean elders. METHODS: Standardized face-to-face interviews, neurological examinations, and physical examinations were conducted in 714 randomly sampled community-dwelling Korean elders aged >or=65 years. Diagnoses of stroke and TIA were made according to the World Health Organization criteria. RESULTS: Age- and education-standardized prevalences of stroke, TIA, and cerebrovascular disorder (implying stroke or TIA) were estimated to be 10.1%, 8.9%, and 15.4%, respectively, in Korean elders. Hypertension and current smoking were associated with the risk of stroke, whereas atrial fibrillation, high diastolic blood pressure, high serum low-density lipoprotein cholesterol, and hypertension were associated with the risk of TIA. Cerebrovascular disorder was associated with the risk of major depressive disorder, vascular dementia, and nonamnestic mild cognitive impairment (P<0.05). CONCLUSIONS: Prevalences of stroke and TIA in Korean elders were higher than in white elders. Stroke and TIA were associated with increased risk of depression and cognitive disorders.


Subject(s)
Aging/physiology , Ischemic Attack, Transient/epidemiology , Stroke/epidemiology , Age Factors , Aged , Aged, 80 and over , Education , Female , Health , Hemodynamics/physiology , Humans , Hyperlipidemias/complications , Hyperlipidemias/epidemiology , Hypertension/complications , Hypertension/epidemiology , Ischemic Attack, Transient/complications , Korea/epidemiology , Lipids/blood , Longitudinal Studies , Male , Mental Disorders/epidemiology , Mental Disorders/etiology , Neuropsychological Tests , Risk Factors , Smoking/epidemiology , Socioeconomic Factors , Stroke/complications
19.
Dement Geriatr Cogn Disord ; 26(3): 270-6, 2008.
Article in English | MEDLINE | ID: mdl-18841012

ABSTRACT

BACKGROUND/AIMS: We estimated the prevalence of dementia and its major subtypes in an elderly urban Korean population. METHODS: A study population of 1,118 Korean elders was randomly sampled from the residents aged 65 years or older living in Seongnam, Korea. Standardized face-to-face interviews, and neurological and physical examinations were conducted on 714 respondents. Dementia was diagnosed according to the DSM-IV diagnostic criteria, and its subtypes were determined according to the criteria of the NINCDS-ADRDA, the NINDS-AIREN, and the consensus guideline proposed by McKeith et al. [Neurology 1996;47:1113-1124]. RESULTS: The estimated age- and gender-standardized prevalences were 6.3% for dementia (95% CI = 4.5-8.1), 4.8% for Alzheimer's disease (AD; 95% CI = 3.3-6.4), 1.0% for vascular dementia (VD; 95% CI = 0.3-1.8), and 0.4% for dementia with Lewy bodies (DLB; 95% CI = 0.0-0.9). The prevalence of AD consistently increased with age, whereas that of VD peaked at age 75-79 years and decreased thereafter. Of the dementia patients, 72.0% were in the very mild or mild stages of the disease. CONCLUSIONS: The prevalence of dementia in a typical urban area of Korea was estimated to be 6.3%, and AD was the most prevalent subtype. DLB was less prevalent than VD among these community-dwelling Korean elders.


Subject(s)
Aging , Alzheimer Disease/ethnology , Asian People/statistics & numerical data , Dementia, Vascular/ethnology , Lewy Body Disease/ethnology , Aged , Aged, 80 and over , Female , Humans , Korea/epidemiology , Longitudinal Studies , Male , Middle Aged , Prevalence , Severity of Illness Index , Urban Population/statistics & numerical data
20.
Neurosci Lett ; 446(1): 1-6, 2008 Nov 28.
Article in English | MEDLINE | ID: mdl-18804514

ABSTRACT

We tend to simulate or recall others' appraisals through auditory verbal imagery (AVI) process to react appropriately. In particular, the ability to imagine derogatory appraisals by others may be critically important for social survival. In this study, we investigated the neural correlates implicated in the processing of unpleasant emotion related to derogatory remark and its self-directedness during AVI process. Twenty-three right-handed healthy human subjects participated in our study. We asked each subject to imagine hearing one's own or another person's voice saying derogatory or non-derogatory neutral remarks during the scanning of functional magnetic imaging. A test of the interaction between derogatory emotion and its self-directedness revealed significant activation of the amygdala. Additionally, we observed decreased neural activity in the anterior cingulate cortex (ACC) during imagery of derogatory remarks compared to neutral remarks. Our findings indicate an important role of the amygdala in the processing of unpleasant emotion or self-relevance of information in the real world may also be expanded to the processing of self-directedness of unpleasant emotion in the imagined world, and thereby contribute to human higher social cognitive process. This study also suggests that deactivation of ACC may enable us to enact vivid affective responses, and thereby contribute to an effective simulation of social interaction.


Subject(s)
Amygdala/physiology , Auditory Perception/physiology , Imagination/physiology , Speech Perception/physiology , Visual Perception/physiology , Adolescent , Adult , Amygdala/anatomy & histology , Cerebral Cortex/anatomy & histology , Cerebral Cortex/physiology , Emotions/physiology , Female , Functional Laterality/physiology , Humans , Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Male , Statistics as Topic , Young Adult
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