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There are growing concerns about the impact of the COVID-19 pandemic on the mental health of older adults. We examined the effect of the pandemic on the risk of depression in older adults.
We analyzed data from the prospective cohort study of Korean older adults, which has been followed every 2 years. Among the 2308 participants who completed both the third and the fourth follow-up assessments, 58.4% completed their fourth follow-up before the outbreak of COVID-19 and the rest completed it during the pandemic. We conducted face-to-face diagnostic interviews using Mini International Neuropsychiatric Interview and used Geriatric Depression Scale. We performed generalized estimating equations and logistic regression analyses.
The COVID-19 pandemic was associated with increased depressive symptoms in older adults [b (standard error) = 0.42 (0.20), p = 0.040] and a doubling of the risk for incident depressive disorder even in euthymic older adults without a history of depression (odds ratio = 2.44, 95% confidence interval 1.18–5.02, p = 0.016). Less social activities, which was associated with the risk of depressive disorder before the pandemic, was not associated with the risk of depressive disorder during the pandemic. However, less family gatherings, which was not associated with the risk of depressive disorder before the pandemic, was associated with the doubled risk of depressive disorder during the pandemic.
The COVID-19 pandemic significantly influences the risk of late-life depression in the community. Older adults with a lack of family gatherings may be particularly vulnerable.
We calculated the human resources required for an antimicrobial stewardship program (ASP) in Korean hospitals.
Multicenter retrospective study.
Eight Korean hospitals ranging in size from 295 to 1,337 beds.
The time required for performing ASP activities for all hospitalized patients under antibiotic therapy was estimated and converted into hours per week. The actual time spent on patient reviews of each ASP activity was measured with a small number of cases, then the total time was estimated by applying the determined times to a larger number of cases. Full-time equivalents (FTEs) were measured according to labor laws in Korea (52 hours per week).
In total, 225 cases were reviewed to measure time spent on patient reviews. The median time spent per patient review for ASP activities ranged from 10 to 16 minutes. The total time spent on the review for all hospitalized patients was estimated using the observed number of ASP activities for 1,534 patients who underwent antibiotic therapy on surveillance days. The most commonly observed ASP activity was ‘review of surgical prophylactic antibiotics’ (32.7%), followed by ‘appropriate antibiotics recommendations for patients with suspected infection without a proven site of infection but without causative pathogens’ (28.6%). The personnel requirement was calculated as 1.20 FTEs (interquartile range [IQR], 1.02–1.38) per 100 beds and 2.28 FTEs (IQR, 1.93–2.62) per 100 patients who underwent antibiotic therapy, respectively.
The estimated time required for human resources performing extensive ASP activities on all hospitalized patients undergoing antibiotic therapy in Korean hospitals was ~1.20 FTEs (IQR, 1.02–1.38) per 100 beds.
This study aimed to investigate the influences of age, education, and gender on the two total scores (TS-I and TS-II) of the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychological assessment battery (CERAD-NP) and to provide normative information based on an analysis for a large number of elderly persons with a wide range of educational levels.
In the study, 1,987 community-dwelling healthy volunteers (620 males and 1,367 females; 50–90 years of age; and zero to 25 years of education) were included. People with serious neurological, medical, and psychiatric disorders (including dementia) were excluded. All participants underwent the CERAD-NP assessment. TS-I was generated by summing raw scores from the CERAD-NP subtests, excluding Mini-Mental State Examination and Constructional Praxis (CP) recall subtests. TS-II was calculated by adding CP recall score to TS-I.
Both TS-I and TS-II were significantly influenced by demographic variables. Education accounted for the greatest proportion of score variance. Interaction effect between age and gender was found. Based on the results obtained, normative data of the CERAD-NP total scores were stratified by age (six overlapping tables), education (four strata), and gender.
The normative information will be very useful for better interpretation of the CERAD-NP total scores in various clinical and research settings and for comparing individuals’ performance of the battery across countries.
In the present study, a porcine system was supplemented with sorbitol during in vitro maturation (IVM) or in vitro culture (IVC), and the effects of sorbitol on oocyte maturation and embryonic development following parthenogenetic activation were assessed. Porcine immature oocytes were treated with different concentrations of sorbitol during IVM, and the resultant metaphase II stage oocytes were activated and cultured in porcine zygote medium-3 (PZM-3) for 7 days. No significant difference was observed in cumulus expansion and the nuclear maturation between the control and sorbitol-treated groups, with the exception of the 100 mM group, which showed significantly decreased nuclear maturation and cumulus expansion. There was no significant difference in the intracellular reactive oxygen species (ROS) levels between oocytes matured with 10 or 20 mM sorbitol and control groups, but 50 and 100 mM groups had significantly higher ROS levels than other groups. The 20 mM group showed significant increases in intracellular glutathione and subsequent blastocyst formation rates following parthenogenetic activation compared with the other groups. During IVC, supplementation with sorbitol significantly reduced blastocyst formation and increased the apoptotic index compared with the control. The apoptotic index of blastocysts from the sorbitol-treated group for entire culture period was significantly higher than those of the partially sorbitol-exposed groups. Based on these findings, it can be concluded that the addition of a low concentration of sorbitol (20 mM) during IVM of porcine oocytes benefits subsequent blastocyst development and improves embryo quality, whereas sorbitol supplement during IVC has a negative effect on blastocyst formation.
Background: The influences of demographics, culture, language, and environmental changes on Mini-Mental State Examination (MMSE) scores are considerable.
Methods: Using a sample of 7452 healthy, community-dwelling elderly Koreans, aged 55 to 94 years, who participated in the four ongoing geriatric cohorts in Korea, we investigated demographic influences on MMSE scores and derived normative data for this population. Geropsychiatrists strictly excluded subjects with cognitive disorders according to the protocol of the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet (CERAD-K) Clinical Assessment Battery (CERAD-K-C).
Results: Education (standardized β = 0.463), age (standardized β = −0.303), and gender (standardized β = −0.057) had significant effects on MMSE scores (p < 0.001). The score of MMSE increase 0.379 point per 1-year education, decrease 0.188 per 1-year older, and decrease 0.491 in women compared to men. Education explained 30.4% of the scores’ total variance, which was much larger than the variances explained by age (8.4%) or gender (0.3%). Accordingly, we present normative data for the MMSE stratified by education (0, 1–3, 4–6, 7–9, 10–12, and ≥ 13 years), age (60–69, 70–79, and 80–89 years), and gender.
Conclusions: We provide contemporary education-, age-, and gender-stratified norms for the MMSE, derived from a large, community-dwelling elderly Korean population sample, which could be useful in evaluating individual MMSE scores.
This paper provides an overview of the development and application of the National Aquatic Ecological Monitoring Program (NAEMP) in Korea, which uses biological and habitat–riparian criteria for river/stream and watershed management. Development of NAEMP began in 2003, with recognition by the Korean Ministry of Environment (MOE) of the limitations of applying chemical parameters (e.g., biochemical oxygen demand (BOD)) as the principal targets of water environment management. Ecosystem health criteria under NAEMP were developed from 2003 to 2006. Candidate sites for monitoring were also screened and established across the country. NAEMP was implemented in 2007, and since then a standard protocol of nationwide monitoring based on multi-criteria has been implemented to assess the ecological condition of rivers and streams. The monitoring results indicate that many Korean rivers and streams are severely degraded, with biological conditions that are much worse than their water chemistry suggests. In 2009, 24% of rivers and streams were in classes C (Fair) and D (Poor) for BOD, but more than 71, 53, and 27% were categorized as Fair to Poor according to fish, diatom, and benthic macroinvertebrate assemblages, respectively. NAEMP is promising in that the results have already had great impacts on policy making and scientific research relevant to lotic water environment and watershed management in Korea. In the future, NAEMP results will be used to develop more aggressive regulations for the preservation and restoration of rivers/streams, riparian buffer areas and watersheds. Another future aim of the NAEMP is to develop aquatic ecological modeling based on the monitoring results.
The prevalence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains causing bloodstream infection (BSI) has not been studied in Korea.
We sought to determine the prevalence of CA-MRSA strains among isolates recovered from patients with MRSA BSIs and to explore epidemiological changes in Korea. We also sought to evaluate clinical characteristics relevant to the development of healthcare-associated BSIs.
We prospectively collected consecutive MRSA isolates from patients with BSI at 4 hospitals from July 1 through November 30, 2007, and we also included MRSA isolates recovered from culture of blood samples collected during a previous year (October 1, 2004 through September 30, 2005) at a different hospital. Molecular typing studies were performed, including pulsed-field gel electrophoresis (PFGE), multilocus sequence typing, Staphylococcus protein A (spa) typing, and staphylococcal cassette chromosome mec (SCCmec) typing. We compared the clinical characteristics and outcomes of patients with healthcare-associated BSI due to CA-MRSA strains with those of patients with healthcare-associated BSI due to healthcare-associated MRSA (HA-MRSA) strains.
There were 76 cases of MRSA BSI, of which 4 (5.3%) were community-associated and 72 (94.7%) were healthcare-associated. Among the 72 HA-MRSA BSIs, 18 (25%) were community onset, and 54 (75%) were hospital onset. PFGE type D-ST72–spa B-SCCmec type IVA MRSA, the predominant genotype of CA-MRSA in Korea, accounted for 19 (25%) of all 76 MRSA BSIs, including 17 (23.6%) of 72 HA-MRSA BSIs and 11 (20.8%) of 53 hospital-onset HA-MRSA BSIs. Patients with healthcare-associated BSIs due to CA-MRSA strains carrying SCCmec type IVA tended to have fewer healthcare-associated risk factors, compared with patients with healthcare-associated BSIs due to HA-MRSA strains carrying other SCCmec types. The presence of a central venous catheter or other invasive device was the only independent factor differentiating patients infected with hospital-associated genotype strains from patients infected with other strains. Clinical outcomes were similar between both groups.
CA-MRSA strains are emerging as a major cause of BSI in healthcare settings in Korea. This changing epidemiology of MRSA poses a challenge to public health and infection control in hospital settings.
The low frequency noise of individual ZnO nanowire (NW) field effect transistors (FETs) exposed to air is systematically characterized. The measured noise power spectrum shows a classical 1/f type. The noise amplitude is independent of source-drain current and inversely proportional to gate voltage. The extracted Hooge's constant of ZnO NW is found to be 6.52×10−3. In addition, the low frequency noise of ZnO NW according to NW resistance and contact property are investigated. The noise amplitude is proportional to the square of ZnO NW resistance. If a sample shows a nonlinear current-voltage (I-V) characteristic due to a poor electrical contact, the noise power spectrum is proportional to the third power of current instead of the square of current.
We demonstrate that ferroelectric memory is very eligible to become a non-volatile cache solution, in particular, in a multimedia storage system such as solid-state disk. It could provide benefits both of performance and of reliability. In performance, a FRAM cache allows us to rid overhead of power-off recovery. Random WRITE performance has been improved by 250%. In assertion of endurance, we investigate acceleration factors to evaluate cycle-to-failure of the ferroelectric memory both in device-level and in capacitor-level. What has been found is that ferroelectric memory cells have 6.0×1014 of the cycle-to-failure at the operational condition of 85 o C and 2.0V. This cycle-to-failure is well above lifetime READ/WRITE cycles of 9.5×1013 in such system. From 2-dimensional stress simulation, it has also been concluded that the number of dummy cells plays a critical role in qualifying the high temperature life tests.
Field effect transistors(FETs) made of ZnO nanowires are very sensitive to the gas environment, so that the passivation can be a good way to get reliable nanowire FETs with longer lifetime and the better mobility. The studies on the passivation effects with the positive electron-beam resist was investigated by selectively covering the part of nanowire devices between the electrodes. Reproducible electrical characteristics were recorded, reflecting the stable electrical properties by the passivation which deters the degradation of a device. Considering the defect states of oxide nanowires dominate the charge states, the pre-state just before the passivation process will be crucial to understand the reproducible and controllable device characteristics of nanowire devices.
Compared to plastic, from the view point of ultra low temperature poly-Si (ULTPS) processes for realizing flexible active matrix organic light emitting diode (AM-OLED) display, SSF offers high thermal resistance and chemical stability, and lithography stability. As SSF is stiffer than plastic film, SSF is expected to reduce stress which originates from difference in coefficient of thermal expansion. However, SSF substrate itself also bears surface roughness problem, which necessitates an appropriate planarization step. Also to fully integrate both the drive circuits and the pixel thin-film transistor(TFT)s in a monolithic complementary metal-oxide-semiconductor (CMOS) technology high mobility is required, calling for poly-Si usage.
We will deal with the planarization process, and then address various processing issues. Especially, we will demonstrate our successful SLS of Si on SSF substrates. Finally we show the device performances. All fabrication temperatures were kept below 200 oC to meet a ULTPS process.
Due to the rolling process for manufacturing foils, the SSF surface is rough. We have measured average roughness of 500 nm, respectively. With benzocyclobutene (BCB), we have successfully planarized the surface with average roughness was less than 0.5 nm.
Our TFT's active layer was obtained by laser crystallizing amorphous Si (a-Si) films. To obtain a high quality gate dielectric film, we formed a SiO2 film using an O2 plasma treatment on the surface of the poly-Si film and then deposited Al2O3 film by plasma enhanced atomic layer deposition. Then gate metal was deposited and patterned. Source and drain regions were p+ doped by ion implantation to form a self-aligned gate structure. We have used SiNx film as interlayer dielectrics.
Briefly we discuss a practical approach for realizing SLS on a SiO2 buffer. The Si-on-SiO2 layer stacking is energetically unstable. Should have not controlled the heat during laser crystallization, liquid Si would recede to expose the SiO2 layer. Dewetting is suppressed by adjusting the buffer density, and densifying the a-Si film. To implement the SLS, we have optimally conjugated the densities of the buffer film and the a-Si film to produce Si grains with sizes of ~6 ¥ìm on a BCB planarized SSF.
Our p-channel TFT transfer performance exhibits a field effect mobility (¥ì) of 95 cm2/Vs, a threshold voltage (Vt) of -3 V and a sub-threshold swing(S-S) of 0.5 V/dec.. The off-current level is ~ 10 pA at drain voltage (Vd) of -1V and the Ion/Ioff is 106 . Especially our stable Vt consents to the electrical stability for driving displays. This feature might be attributed to the improved interface between the active layer and the gate dielectrics by plasma oxidation.
To compare the epidemiology and genetic relatedness of Candida tropicalis isolates causing bloodstream infection (BSI) in two hospitals.
Two tertiary-care hospitals in Korea.
A retrospective molecular epidemiologic analysis using pulsed-field gel electrophoresis (PFGE) was performed with 49 C. tropicalis isolates from sporadic cases of BSI. The isolates were collected from 27 patients at Chonnam National University Hospital (CUH) during a 6-year period and 22 patients at Asan Medical Center (AMC) during a 2-year period.
Based on the PFGE patterns, the average similarity value (SAB) for the 27 isolates from CUH was 0.84 ± 0.08, which was significantly higher than that for the 22 isolates from AMC (0.78 ± 0.06; P < .001). Of the 49 strains from patients at the 2 hospitals, 9 isolates were placed into 3 subtypes with SAB values of 1.0, which indicated that they were identical. All 9 of these strains were isolated from CUH patients, and each type strain was isolated sporadically during a period ranging from 4 months to 3 years. On comparison of the clinical characteristics of the patients of the 2 hospitals, the CUH strains were isolated more frequently from non-neutropenic patients and patients with central venous catheter–related fungemia; cases from CUH had a better outcome than those from AMC (P < .05).
These data show that the clinical and epidemiologic characteristics of C. tropicalis fungemia may differ markedly among hospitals and that some cases of C. tropicalis fungemia may be caused by endemic strains within a hospital.
This study aimed to explore the effects of age, education and gender
on the performance of eight tests in the Korean version of the CERAD
neuropsychological assessment battery and to provide normative
information on the tests in the Korean elderly. The battery was
administered to 618 healthy volunteers aged from 60 to 90. People with
serious neurological, medical and psychiatric disorders, including
dementia, were excluded. Multiple linear regression analyses were
performed to assess the relative contribution of the demographic
factors on the score of each cognitive test. Age, education, and gender
were found to have significant effects on the performance of many tests
in the battery. Based on these results, 4 overlapping age normative
tables (60 to 74, 65 to 79, 70 to 84, and 75 to 90 years of age) with 3
educational strata (0 to 3 years, 4 to 6 years, and 7 years and more)
for both genders are presented. The normative information will be
useful for a clinical interpretation of the CERAD neuropsychological
battery in Korean elderly as well as for comparing the performance of
the battery across countries. (JINS, 2004, 10,
SiON thin films were deposited by plasma-enhanced chemical vapor deposition method at 350 °C using N2O/SiH4 gas mixtures as precursors. As-deposited SiON films were annealed in different gas atmospheres (air, N2, and O2) and at different annealing temperatures (800 oC ∼ 1100 oC). Effects of annealing atmosphere on the Si-O, Si-N, Si-H, and N-H bonding characteristics in SiON films and their structural and optical properties have been investigated. Cross-sectional and planar microstructures were characterized by scanning electron microscopy and atomic force microscopy, and crystallinity was investigated by X-ray diffraction. Chemical bonding characteristics and optical properties SiON films were studied using fourier transform infrared spectroscopy and prism coupler. Xray diffractions showed no evidence of any crystals in all SiON films. The deposition rate strongly depended on the processing parameters such as radio frequency (rf) power, N2O/SiH4 flow ratio, and SiH4 flow rate. Deposition rate increased as N2O/SiH4 flow ratio increased and SiH4 flow rate increased. It was possible to obtain SiON films with surface roughness of about 1 nm and a high deposition rate of about 4 μm/h when the processing parameters were optimized as rf power of 200 W, N2O/SiH4 flow ratio of 3, SiH4 flow rate of 100 sccm. It was observed that the intensity and the shift of the Si-O stretch and Si-N peaks depended on the annealing atmosphere as well as the annealing temperature. The intensity of Si-O peaks increased in the samples annealed in oxygen atmosphere, but it decreased in the samples annealed in nitrogen atmosphere. The intensity of Si-N peak decreased in the samples annealed in oxygen atmosphere, but it increased in the samples annealed in nitrogen atmosphere. The position of Si-O peaks shifted from 1030 nm to 1140 nm in the samples annealed both in oxygen and in nitrogen atmosphere. It was also observed that the intensities of Si-H (∼2250 cm−1) and N-H (∼3550 cm−1) peaks decreased apparently as the annealing temperature increased in all annealed samples.
RF MEMS(Micro-Electro-Mechanical-System) switch technology is one of powerful solution for future RF systems. This technology provides low insertion loss, High linearity and broad bandwidth. Wide driving membrane used MEMS switch can reduce driving voltage but it is easy to bend because of the stress gradient. In order to solve this problem we fabricated Au cantilever in various sputtering condition and various substrate materials. As a result of this experiment, we fabricated cantilever which was bent within 1 um, with 2 um thickness and 340 um length. We applied this condition to RF MEMS switch and we fabricated switch membrane within 1 um bend, under 10MPa stress gradient.
The highly strained interfacial structure and reaction of Co on Si(111) in the initial growth stage was studied by in-situ surface x-ray scattering. Co was deposited on Si(111) – (7×7) reconstruction by electron beam evaporation in ultra high vacuum. Our study reveals that the interfacial layer, formed by the reaction of Co with Si in the initial growth stage at room temperature, is a silicide layer with stoichiometry of Co2Si. The interfacial silicide layer is a commensurate phase of pseudohexagonal Co2Si, which shows a significant local atomic displacements imposed by Si substrate. The intensity oscillations at the anti-Bragg position with Co coverage show that a layer-by-layer consumption of silicon substrate occurs for the first 15 monolayers (ML) of Co deposited.
Well-crystallized Pb(Zr0.52Ti0.48)O3 thin films (4000 Å thickness) can be synthesized on Pt/Ti/SiO2/Si(100) substrate at a temperature as low as 520 °C. The polycrystalline lead zirconate titanate (PZT) perovskite phase formation was confirmed with x-ray diffraction (XRD) analysis, and growth morphologies were studied with a scanning electron microscope (SEM). The electrical properties of PZT thin films were characterized through P-E hysteresis curve, dielectric constant, and loss, fatigue, and leakage current measurements. Remanent polarization (Pr) and coercive field (Ec) of as-grown film were 8–30 μC/cm2 and 24–64 kV/cm with the variation of applied voltage (5–15 V). The post-annealing enhances the electrical properties even at 500 °C, which is below the as-grown temperatures (520 °C). The average polarization loss after applying rectangular pulse (Vp-p = 10 V) up to 1011 cycles was 40.9% for a 300 μm small dot and 22% for a 500 μm large dot, which are relatively improved values for platinum electrode. The values of dielectric constant (ε′) and tan δ measured with small signal sign wave (1 V, 10 kHz) were 1207 and 0.066 in the case of as-grown film.
The lead zirconate titanate (PZT) thin film was deposited on platinized silicon wafer substrate by the rf magnetron sputtering method. In order to investigate the effect of cooling ambient, oxygen partial pressure was controlled during cooling PZT films. The PZT films cooled at lower oxygen partial pressure had perovskite phase and pyrochlore phase in both as-grown and postannealed films, but in the PZT films cooled at higher oxygen partial pressure, pyrochlore phases were not detected by XRD. As the oxygen partial pressure became lower during cooling, the capacitors had low values of remanent polarization and coercive field for as-grown films. The PZT capacitor with such a low value was recovered by postannealing in air, but its electrical properties had the same tendency before and after annealing. Microstructure was also affected by cooling ambient. Higher oxygen partial pressure on cooling reduced the number of very fine grains, and enhanced uniform grain distribution. Fatigue characteristics were also enhanced by cooling at higher oxygen partial pressure. However, the imprint was negligible irrespective of oxygen partial pressure upon cooling. The cooling procedure at higher oxygen ambients is believed to reduce the amounts of nonferroelectric second phases and oxygen vacancies. We find that oxygen partial pressure during cooling is a considerable process parameter. Therefore, care should be taken in treating the parameter after depositing films.
An optimized process of Pb(Zr,Ti)O3(PZT) ferroelectric capacitor has been investigated in order to develop a highly scaleable 1T/1C ferroelectric random access memory. The PZT ferroelectric capacitor, Pt/PZT/Pt stack, was formed on the TiO2/SiO2/Si substrate. The PZT thin films were prepared by conventional sol-gel multi-coating method. Physical and electrical properties of the PZT ferroelectric capacitors were characterized by XRD, SEM, TEM and RT6000S, respectively.
It was revealed that the microstructure of PZT thin film is strongly influenced by sol-gel coating process, especially depending on coating methods of the first PZT layer. The second phase was observed in the PZT thin films, which is found to be pyrochlore phase. The size and density of pyrochlore phase were significantly reduced by modifying the coating methods of first PZT layer. Microstructure of PZT thin film capacitors was evaluated in detail along with electrical properties such as remnant polarization, coercive electric field, and dielectric leakage. The sensing Pr window was also introduced for proper sensing margin in IT/1C ferroelectric random access memory. This concept is well verified by 64Kb 1T/1C ferroelectric random access memory.