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Firefighters are routinely exposed to various traumatic events and often experience a range of trauma-related symptoms. Although these repeated traumatic exposures rarely progress to the development of post-traumatic stress disorder, firefighters are still considered to be a vulnerable population with regard to trauma.
To investigate how the human brain responds to or compensates for the repeated experience of traumatic stress.
We included 98 healthy firefighters with repeated traumatic experiences but without any diagnosis of mental illness and 98 non-firefighter healthy individuals without any history of trauma. Functional connectivity within the fear circuitry, which consists of the dorsal anterior cingulate cortex, insula, amygdala, hippocampus and ventromedial prefrontal cortex (vmPFC), was examined using resting-state functional magnetic resonance imaging. Trauma-related symptoms were evaluated using the Impact of Event Scale – Revised.
The firefighter group had greater functional connectivity between the insula and several regions of the fear circuitry including the bilateral amygdalae, bilateral hippocampi and vmPFC as compared with healthy individuals. In the firefighter group, stronger insula–amygdala connectivity was associated with greater severity of trauma-related symptoms (β = 0.36, P = 0.005), whereas higher insula–vmPFC connectivity was related to milder symptoms in response to repeated trauma (β = −0.28, P = 0.01).
The current findings suggest an active involvement of insular functional connectivity in response to repeated traumatic stress. Functional connectivity of the insula in relation to the amygdala and vmPFC may be potential pathways that underlie the risk for and resilience to repeated traumatic stress, respectively.
Historically, patient access processes of new and innovative medical devices including in-vitro diagnostics are made in the sequence of regulatory approval, new Health Technology Assessment (nHTA) approval, reimbursement coverage and coding finally reaching the pricing approval stage in South Korea. Although the individual patient access process has its own distinct objective and perspective, there are still opportunities for the authorities or agencies in charge to streamline their processes by working together to promote earlier patient access of new and innovative medical devices to patients without impacting their own decision making.
This research examined and analyzed the current policies about: patient access processes with a holistic viewpoint, industry-wide survey about patient access practices; case studies of two innovative medical devices for patient access in South Korea and also proposed new or alternative programs which can contribute to patient access harmonization efforts with a holistic approach.
Historically, health authorities play defensive strategies by delaying the adoption of new and innovative medical devices and implementing certain periods (that is, 2 to 5 years) for a patient's out-of-pocket payment scheme. It is well illustrated with the statistic that only twenty-nine percent of new and innovative medical technologies which have successfully gone through the nHTA process were determined for reimbursement coverage in the past 7 years.
The survey by the medical device industry to determine the patient access lead-time of innovative medical devices with a holistic perspective indicated significantly delayed patient access even considerabley exceeding the legally required decision-making lead time. The in-depth case studies with two innovative devices indicated the disadvantageous patient access processes to the innovator in terms of both final approval timing and the price level.
The concurrent review process for reimbursement coverage decision making for medical procedures, medical devices and reimbursement coverage payment guidelines committed within the Health Insurance Review and Assessment Service shall be created. New programs to deal with uncertainty in reimbursement coverage decision making shall be considered such as coverage with evidence development, performance-based risk-sharing arrangement, multi-criteria decision analysis and economic evaluation.
The US and Japan, despite their shared reputation as leading donors for international development, remarkably varied in their foreign aid policy for HIV/AIDS in the 1980s and 1990s. Unlike the US, who initiated and increased global AIDS funding dramatically, Japan was lukewarm in its contributions. I claim that the distinctive pattern depends on how the pandemic was domestically framed and understood. The policy commitment was more likely when the internationally shared idea (international norms) of threats requiring immediate international cooperation was congruent with the domestic perception of the epidemic. The research undertakes a comparative examination of the determinants of the distinctive domestic perceptions of the two cases, including the number of individuals infected with HIV, the attitude and role of the media, and the civil society organizations dealing with HIV/AIDS. They played significant roles as intervening variables that conditioned domestic diffusion or internalization of the international norms for foreign aid policy development. The US had a favorable domestic condition based upon the relatively large number of those infected with HIV, a media that adopted a constructive approach, and active civil society organizations associated with the disease. In contrast, in Japan the number of HIV cases was lower, the media had a distorted view of the epidemic, and civil society organizations were not strong enough to offer much support until the early 1990s.
We demonstrate the tungsten disulfide (WS2) thin film catalysts prepared by the sulfurization of vacuum deposited WO3 thin films for efficient hydrogen production with over 90% Faradaic efficiency. The 23-nm-thick WS2 thin film catalyst heterojunction with p-type silicon photocathode could exhibit a photocurrent density of 8.3 mA/cm2 at 0 V versus a reversible hydrogen electrode (RHE), a low onset potential of 0.2 V versus RHE when photocurrent density reaches −1 mA/cm2 and long-term stability over 10 h. The enhanced catalytic activities of WS2/p-Si photocathodes compared with the bare p-Si photocathode originate from a number of edge sites in the synthesized polycrystalline thin films, which could act as hydrogen evolution catalyst.
To examine the hypothesis that the association between vitamin D deficiency and depressive symptoms is dependent upon total cholesterol level in a representative national sample of the South Korean population.
This was a population-based cross-sectional study.
The Fifth Korean National Health and Nutrition Examination Survey (KNHANES V, 2010–2012).
We included 7198 adults aged 20–88 years.
The incidence of depressive symptoms in individuals with vitamin D deficiency (serum 25-hydroxyvitamin D<20 ng/ml) was 1·54-fold (95 % CI 1·20, 1·98) greater than in individuals without vitamin D deficiency (serum 25-hydroxyvitamin D ≥20 ng/ml). The relationship was stronger in individuals with normal-to-borderline serum total cholesterol (serum total cholesterol<240 mg/dl; OR=1·60; 95 % CI 1·23, 2·08) and non-significant in individuals with high serum total cholesterol (OR=0·97; 95 % CI 0·52, 1·81) after adjustment for confounding variables (age, sex, BMI, alcohol consumption, smoking status, regular exercise, income level, education level, marital status, changes in body weight, perceived body shape, season of examination date and cholesterol profiles).
The association between vitamin D deficiency and depressive symptoms was weakened by high serum total cholesterol status. These findings suggest that both vitamin D and total cholesterol are important targets for the prevention and treatment of depression.
Cerebral white matter hyperintensities (WMH) are prevalent incident findings on brain MRI scans among elderly people and have been consistently implicated in cognitive dysfunction. However, differential roles of WMH by region in cognitive function are still unclear. The aim of this study was to ascertain the differential role of regional WMH in predicting progression from mild cognitive impairment (MCI) to different subtypes of dementia.
Participants were recruited from the Clinical Research Center for Dementia of South Korea (CREDOS) study. A total of 622 participants with MCI diagnoses at baseline and follow-up evaluations were included for the analysis. Initial MRI scans were rated for WMH on a visual rating scale developed for the CREDOS. Differential effects of regional WMH in predicting incident dementia were evaluated using the Cox proportional hazards model.
Of the 622 participants with MCI at baseline, 139 patients (22.3%) converted to all-cause dementia over a median of 14.3 (range 6.0–36.5) months. Severe periventricular WMH (PWMH) predicted incident all-cause dementia (Hazard ratio (HR) 2.22; 95% confidence interval (CI) 1.43–3.43) and Alzheimer's disease (AD) (HR 1.86; 95% CI 1.12–3.07). Subcortical vascular dementia (SVD) was predicted by both PWMH (HR 16.14; 95% CI 1.97–132.06) and DWMH (HR 8.77; 95% CI 1.77–43.49) in more severe form (≥ 10 mm).
WMH differentially predict dementia by region and severity. Our findings suggest that PWMH may play an independent role in the pathogenesis of dementia, especially in AD.
The study's aim was to examine the association of alcohol consumption with verbal and visuospatial memory impairment in older people.
Participants were 1,572, aged ≥60 years, in the hospital-based registry of the Clinical Research Center for Dementia of South Korea (CREDOS). Moderate drinking was defined as no more than seven drinks per week and three drinks per day. Memory impairment was defined as performance with more than 1 standard deviation below the mean value on the Seoul Verbal Learning Test and Rey Complex Figure Test.
Those who consumed alcohol moderately, compared with abstainers, had a lower odds of verbal memory impairment (Odds Ratio [OR] = 0.64; 95% Confidence Interval [CI]: 0.46–0.87), adjusting for covariates. Visuospatial memory, however, was not significantly associated with alcohol consumption.
Moderate alcohol drinking is associated with a reduced likelihood of verbal memory impairment among older people attending memory clinics.
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.
We assessed eight-year mortality rates and predictors in a rural cohort of elderly individuals with cognitive impairment.
A total of 1,035 individuals, including 155 (15.0%) individuals with cognitive impairment, no dementia (CIND), and 69 (6.7%) individuals with clinically diagnosed dementia were followed for eight years from 1997. The initial assessment involved a two-step diagnostic procedure performed during a door-to-door survey, and mortality data were obtained from the Korean National Statistical Office (KNSO). The relationship between clinical diagnosis and risk of death was examined using the Cox proportional hazards model after adjusting for age, sex, and education.
During follow-up, 392 individuals died (37.9%). Compared to persons without cognitive impairment, mortality risk was nearly double among those with CIND (hazard ratio [95% confidence interval], 1.92 [1.46–2.54]), and this increased more than three-fold among those with dementia (3.20 [2.30–4.44]). Old age and high scores on the behavioral changes scale at diagnosis were two common predictors of mortality among those with CIND and dementia. Among the items on the behavioral changes scale, low sociability, less spontaneity, and poor hygiene were associated with increased mortality in individuals with CIND. Conversely, low sociability, excessive emotionality, and irritability were associated with increased mortality in patients with dementia.
Both dementia and CIND increased mortality risk compared with normal cognition in this community cohort. It is important to identify and manage early behavioral changes to reduce mortality in individuals with CIND and dementia.
Dense thin β/β’’-alumina electrolyte films of less than 50 μm thickness were fabricated using vacuum dip-coating on porous substrate tubes. The porous substrate tubes were fabricated using a slip casting method. Fine Na-β/β’’-alumina powder was obtained via traditional solid state reaction processing. It was found that vacuum dip-coating is an effective method for fabricating thin dense layers coated on the porous tube. The mechanical properties of the porous tube, with and without the dense layer, were tested using a C-ring method. The optimized sintering process was also studied.
A 44-year-old man developed sudden non-fluent aphasia and right hemiplegia due to left striatocapsular infarction (Figure). Neurologic examination revealed gaze deviation to the right with eyes closed, but not with eyes open (Video). There was no spontaneous or gaze-evoked nystagmus, even after elimination of visual fixation. Leftward pursuit was impaired in a craniotopic frame of reference, and horizontal saccades were hypometric in both directions. Head impulse test was normal in the horizontal plane and there were no visual field defects. The contralesional gaze deviation with eye closure persisted for ten days.
The effects of polymer substrates on the interfacial structure and the thermal stability of Ga-doped ZnO (GZO) thin films were investigated. The GZO thin films were deposited on polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) substrates by rf-magnetron sputtering at room temperature, and thermal stability tests of the GZO thin films on the polymer substrates were performed at 150°C up to 8 h in air. Electrical and structural characterizations of the GZO thin films on the PET and the PEN substrates were carried out, and the origins of the stable interfacial structure and the improved thermal stability of the GZO thin film on the PEN substrate were discussed.
The sulfur-iodine thermo-chemical cycle (S-I cycle) is one of the promising nuclear hydrogen production methods combined with a high temperature gas-cooled reactor. However, extremely corrosive environments limit the selection of structural materials. Therefore, in this study, corrosion behaviors of several metallic materials were investigated to screen the candidate metallic materials. Coupon type specimens were exposed for 100 h in simulated SO3 and HI decomposer conditions at 850 °C. After 100 h exposure, the surface treated Alloy 617 showed the superior weight change in both environments. However, scanning electron microscope observation showed oxide spallation for EB-treated and NiAl coated Alloy 617. On the other hand, the Ni3Al coated Alloy 617 showed better corrosion resistance in SO3 decomposer condition, such that only formed external Al-rich oxide layer. Especially, in a HI decomposer condition, the damage on the Ni3Al coated Alloy 617 was considerably less significant probably due to the protection by very thin aluminum-rich oxide on the surface.
Pathological gambling (PG) is a severe and persistent pattern of problem gambling that has been aligned with obsessive-compulsive disorder (OCD). However, no study has compared the neurocognitive profiles of individuals with PG and OCD.
We compared neurocognitive functioning, including executive function, verbal learning and memory, and visual–spatial organization and memory among 16 pathological gamblers, 31 drug-naïve OCD subjects, and 52 healthy controls.
The only neurocognitive marker common to both groups was increased fragmentation errors on the Rey–Osterrieth Complex Figure Test (ROCF). The PG subjects showed increased nonperseverative error on the Wisconsin Card Sorting Test and organization difficulties in the ROCF, whereas the OCD subjects revealed longer response times on the Stroop test and retention difficulties on the immediate recall scale of the ROCF.
A more careful approach is required in considering whether PG is a part of the OCD spectrum, as little evidence of neurocognitive overlap between PG and OCD has been reported.
The catalytic activity of Pt nanoparticles (NPs) significantly influences the electrochemical performance of direct methanol fuel cells. Information about the factors that influence the electrochemical activity of the catalyst themselves is scarce; hence, guidelines for the preparation of Pt NPs that yields the best performances are lacking. With consideration for this situation, we systematically investigated the relationship(s) between the characteristics of Pt NPs and their electrochemical performance. The general characteristics of Pt NPs, such as the average size, loading density, and dispersion status on the support, were varied in the presence of poly(acrylic acid)-wrapped multiwalled carbon nanotubes by controlling the preparation conditions, including the pH of the aqueous solution, the reaction temperature, and the reaction time. The enhanced catalytic activity is attributable to higher degree of dispersion, specific surface area, and electrochemically active surface area of Pt NPs. The optimized catalyst exhibits a ∼165% higher catalytic activity toward methanol oxidation than the commercial E-TEK.
Highly mesoporous TiO2 nanoparticles (NPs) were synthesized by an aero-sol-gel process in this approach. By varying the mass fraction of inorganic templates, the formation of mesoporous TiO2 NPs with optimized surface area and pore volume distributions was examined. Then, the photovoltaic properties of the resulting mesoporous TiO2 NPs were systematically investigated by applying them into the photoanode of dye-sensitized solar cells (DSSCs). The mesoporous TiO2 NP-based DSSCs fabricated in this study showed an improved short circuit current density and power conversion efficiency compared with solid TiO2 NP-based DSSCs due to the increase of the amount of inorganic dye (N719) adsorption in the mesoporous TiO2 NPs. These mesoporous TiO2 NPs fabricated have a strong potential as an effective dye supporting and electron transfer medium to improve the photovoltaic performance of DSSCs.
Geochemical characteristics of marine sediment from the southern Drake Passage were analyzed to reconstruct variations in sediment provenance and transport paths during the late Quaternary. The 5.95 m gravity core used in this study records paleoenvironmental changes during the last approximately 600 ka. Down-core variations in trace element, rare earth element, and Nd and Sr isotopic compositions reveal that sediment provenance varied according to glacial cycles. During glacial periods, detrital sediments in the southern Drake Passage were mostly derived from the nearby South Shetland Islands and shelf sediments. In contrast, interglacial sediments are composed of mixed sediments, derived from both West Antarctica and East Antarctica. The East Antarctic provenance of the interglacial sediments was inferred to be the Weddell Sea region. Sediment input from the Weddell Sea was reduced during glacial periods by extensive ice sheets and weakened current from the Weddell Sea. Sediment supply from the Weddell Sea increased during interglacial periods, especially those with higher warmth such as MIS 5, 9, and 11. This suggests that the influence of deep water from the Weddell Sea increases during interglacial periods and decreases during glacial periods, with the degree of influence increasing as interglacial intensity increases.
The diatoms are an ecologically important group of algae that have been extensively studied by ecologists and taxonomists. However, the large-scale patterns of diatom distribution and the factors underlying this distribution are largely unknown. The aims of this study were to identify the large-scale spatial patterns of benthic diatom assemblages in Korean streams and rivers, and to assess the importance of numerous environmental factors on diatom distribution. We classified 720 study sites based on diatom flora. Benthic diatoms, water chemistry, altitude, and riparian land cover and use were characterized by multivariate analyses, Monte Carlo permutation tests, and indicator species analysis. In total, we identified 531 diatom taxa. Diatom assemblages were mostly dominated by species of the genera Achnanthes, Navicula, Nitzschia, Cocconeis, Fragilaria (Synedra included), Cymbella, Gomphonema, and Melosira. Cluster analysis partitioned all 720 sites into eight groups based on diatom species composition. Canonical correspondence analysis indicated that altitude, land cover and use, current velocity, electrical conductivity, and nutrient levels explained a significant amount of the variation in the composition of assemblages of benthic diatoms. At the national scale, a downstream ecological gradient was apparent, from fast-flowing, mostly oligotrophic highland streams to slow-flowing, mostly eutrophic lowland rivers. Our data suggest that spatial factors explain some of the variation in diatom distribution. The present investigation of the spatial patterns of benthic diatoms, the ecological determinants of diatom occurrence, and the identification of diatom indicator species contributes to development of a program for assessing the biological integrity of lotic ecosystems in Korea.