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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.
Legislative responses to social changes signify how representative democracy works. Yet research is still needed to find out whether and how representatives in new democratic countries address the constituents’ interests and demands. We revisit the 18th National Assembly in Korea (2008–12) to examine legislative activities surrounding the issue of economic inequality. To understand how lawmakers in the new democracy like Korea respond to the demands of redistributive policies, we turn to representatives’ co-sponsorship behaviour. We find that Korean lawmakers do respond to constituents’ preferences. More specifically, Korean lawmakers representing conservative districts tend to care less about economic inequality than other representatives while controlling their partisanship. This study fleshes out the link between the represented and the representatives in a new democracy where party discipline at the expense of constituency connection has long dominated legislative politics.
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.
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.
New MR imaging techniques that limit artifacts in the abdomen have increased the role of MR imaging in detection and characterization of pancreatic disease. Advantages of imaging at 3T compared with 1.5T include thinner section acquisition (typically 2.5 mm versus 5 mm at 1.5T), higher matrix (typically 340 × 516 compared with 192 × 256), and high quality of T1-weighted three-dimensional (3D) gradient echo imaging . Standard sequences at 3T, which include breath-hold T1-weighted 3D gradient echo sequences, fat suppression techniques, and dynamic administration of gadolinium chelate, have resulted in image quality of the pancreas sufficient to detect and characterize focal pancreatic mass lesions smaller than 1 cm in diameter, and to evaluate diffuse pancreatic disease. MR cholangiopancreatography (MRCP) images acquired in a coronal oblique projection to delineate the pancreatic and bile duct is a useful addition. MRCP permits good demonstration of the biliary and pancreatic ducts to assess ductal obstruction, dilation, and abnormal duct pathways. The combination of parenchyma-imaging sequences and MRCP provides comprehensive information to evaluate the full range of pancreatic disease.
We developed a new Cu–Zn wetting layer for Pb-free solders. By adding Zn to the Cu wetting layer, intermetallic growth in the Sn–Ag–Cu (SAC) solder interfaces was delayed. Cu3Sn intermetallic compounds and microvoids were not observed in the SAC/Cu–Zn interfaces after aging. The drop reliability of the SAC solder/Cu–Zn joints was excellent.
We fabricated nc-Si TFTs in order to investigate the effect of the active-layer thickness on the characteristic of the nc-Si TFT. Bottom gate nc-Si TFTs were fabricated at 350°C using ICP-CVD. The thicknesses of the nc-Si layer were remained to 700, 1200 and 1700 Å. As the active-layer thickness increases, the mobility and the on-current level were not altered. However, the off-current level increased considerably and on/off ratio decreased. It may be attributed to highly doped characteristic of thick nc-Si film. As the nc-Si film thicker, the conductivity increases considerably and the Fermi level approaches to the conduction band minimum, which indicates the increases of doping level. The oxygen concentration shows high level of unintentional doping. Also, columnar growth of nc-Si film makes that the crystallinity of top region is much higher than that of bottom region. So, the conductivity of thick nc-Si film becomes high compared to that of thin nc-Si film. The structure of the nc-Si TFT with thick nc-Si film can be similar to the serial connection of N+, N- and N+ resistance, so that it suffers difficulty to suppress the off current and to secure high on/off ratio. Therefore, the off current can be suppressed by thinning of the high conducting active nc-Si layer and nc-Si TFT with channel thickness of 700 Å shows good on/off characteristic. It is deduced that bottom gate nc-Si TFT is necessary to have intrinsic channel layer as well as thin channel layer to reduce the leakage current.
The sap of Acer mono has been called ‘bone-benefit-water’ in Korea because of its mineral and sugar content. In particular, the calcium concentration of the sap of A. mono is 37·5 times higher than commercial spring water. In the current study, we examined whether A. mono sap could improve or prevent osteoporosis-like symptoms in a mouse model. Male mice (3 weeks old) were fed a low-calcium diet supplemented with 25, 50 or 100 % A. mono sap, commercial spring water or a high calcium-containing solution as a beverage for 7 weeks. There were no differences in weekly weight gain and food intake among all the groups. Mice that were given a low-calcium diet supplemented with commercial spring water developed osteoporosis-like symptoms. To assess the effect of sap on osteoporosis-like symptoms, we examined serum calcium concentration, and femur density and length, and carried out a histological examination. Serum calcium levels were significantly lower in mice that received a low-calcium diet supplemented with commercial spring water (the negative control group), and in the 25 % sap group compared to mice fed a normal diet, but were normal in the 50 and 100 % sap and high-calcium solution groups. Femur density and length were significantly reduced in the negative control and 25 % sap groups. These results indicate that a 50 % sap solution can mitigate osteoporosis-like symptoms induced by a low-calcium diet. We also examined the regulation of expression of calcium-processing genes in the duodenum and kidney. Duodenal TRPV6 and renal calbindin-D9k were up-regulated dose-dependently by sap, and the levels of these factors were higher than those attained in the spring water-treated control. The results demonstrate that the sap of A. mono ameliorates the low bone density induced by a low-calcium diet, most likely by increasing calcium ion absorption.
This study investigated the associations among vitamin D receptor (VDR) BsmI polymorphism, calcium intake and bone strength as indicated by the broadband ultrasound attenuation (BUA) measured by calcaneal quantitative ultrasound at the left calcaneus in community-dwelling subjects with a low calcium intake. The VDR BsmI polymorphism was analysed in 335 women older than 65 years residing in rural Asan, Korea. Calcium intake was assessed with a 2 d, 24 h recall method. The distribution of genotypes was similar to that reported in other Asian populations (92 % bb, 7 % Bb and 1 % BB). The calcaneal BUA was significantly higher (P = 0·013) in the bb genotype than in the Bb or BB genotype (Bb and BB genotypes were combined due to the small number of BB subjects) in a multiple regression model after adjusting for age, body weight, height, physical activity and nutritional factors. BUA was not significantly affected by the calcium intake regardless of the genotype, cross-sectionally. The energy-adjusted average calcium intake of this population was 439·6 mg/d (432·5 mg/d for bb and 522·3 mg/d for Bb or BB), and 96 % of the subjects had dietary intakes that were less than the recommended Dietary Reference Intake for Koreans (which for calcium is 800 mg/d for women older than 65 years). In summary, the BUA in older Korean women with a low calcium intake was significantly influenced by the VDR genotype but not by the calcium intake, cross-sectionally.
Oxidative modification of LDL is causally involved in the development of atherosclerosis and occurs in vivo in the blood as well as within the vascular wall. The present study attempted to explore whether polyphenolic flavonoids influence monocyte-endothelium interaction and lectin-like oxidised LDL receptor 1 (LOX-1) expression involved in the early development of atherosclerosis. The flavones luteolin and apigenin inhibited THP-1 cell adhesion onto oxidised LDL-activated human umbilical vein endothelial cells (HUVEC), while the flavanols of ( − )epigallocatechin gallate and (+)catechin, the flavonols of quercetin and rutin, and the flavanones of naringin, naringenin, hesperidin and hesperetin did not have such effects. Consistently, Western blot analysis revealed that the flavones at 25 μm dramatically and significantly abolished HUVEC expression of vascular cell adhesion molecule-1 and E-selectin evidently enhanced by oxidised LDL; these inhibitory effects were exerted by drastically down regulating mRNA levels of these cell adhesion molecules. In addition, quercetin and luteolin significantly attenuated expression of LOX-1 protein up regulated in oxidised LDL-activated HUVEC with a fall in transcriptional mRNA levels of LOX-1. In addition, quercetin and luteolin clearly blunted oxidised LDL uptake by HUVEC treated with oxidised LDL. The results demonstrate that the flavones luteolin and apigenin as well as quercetin were effective in the different initial steps of atherosclerosis process by inhibiting oxidised LDL-induced endothelial monocyte adhesion and/or oxidised LDL uptake. Therefore, certain flavonoids qualify as anti-atherogenic agents in LDL systems, which may have implications for strategies attenuating endothelial dysfunction-related atherosclerosis.
In this study, we assess the neuropsychological profiles of both early
and late symptom-onset obsessive-compulsive disorder (OCD) patients. The
early and late-onset OCD patients are compared to the control group with a
series of neuropsychological measurements. The late-onset OCD patients
exhibited impaired performance on the immediate and the delayed recall
conditions of the Rey-Osterrieth Complex Figure Test (RCFT) and the letter
and category fluency of the Controlled Oral Word Association Test (COWA),
compared to the normal controls and the early-onset OCD patients. The
controls and early-onset OCD patients did not differ on any of the
neuropsychological measurements taken in this study. These results suggest
that different neurophysiological mechanisms are in play in early and
late-onset OCD patients, and age of onset can serve as a potential marker
for the subtyping of OCD. (JINS, 2007, 13,
The thermal degradation behavior of indium tin oxide (ITO) thin films coated on glass substrates using radio frequency (rf) magnetron sputtering was investigated over the temperature range of 100–400 °C in air. The resistivity of ITO films increases abruptly after the thermal degradation temperature of 250 °C is reached, with a slight increase from 200 to 250 °C. The x-ray photoelectron spectrometry intensity ratio of O/(In + Sn) in thermally degraded ITO films is higher than that in normal films. The carrier concentration gradually decreases up to 200 °C, sharply drops between 200 and 250 °C with increasing temperature, and then saturates from 275 °C. The Hall mobility drops suddenly at 275 °C. The diffusion of oxygen into oxygen interstitials and oxygen vacancies and the chemisorption of oxygen into grain boundaries decrease the carrier concentration and the Hall mobility, respectively. The former mainly affects the resistivity of ITO films below 250 °C, and the later above 250 °C.
NiCr films were thermally evaporated on the Mn-Ni-Co-O thick-film substrates. The NiCr/Mn-Ni-Co-O bi-layer systems were tested in a thermal shock chamber with three temperature differences of 150, 175 and 200°C. The systems were considered to have failed when the sheet resistance of NiCr films changed by 30% relative to an initial value. As the cyclic repetition of thermal shock increased, the sheet resistance of NiCr coatings increased. The Coffin-Manson equation was applied to the failure mechanism of cracking of NiCr coatings and the SEM observation of cracks and delamination in NiCr coatings due to thermal cycling agreed well with the failure mechanism.
Porcelain (veneer layer)/alumina (core layer) is a typical dental crown structure. Due to its high incidence of failure, a new porcelain/mullite (buffer layer)/alumina trilayer structure is designed, fabricated, and evaluated. Alumina green bodies were prepared by gel-casting process, and then calcined at 900 and 1100°C to infiltrate mullite precursor slurry of silica-rich (Al2O3·2SiO2) composition into the bodies. Porosity in the bodies is not dependent on calcination temperature, resulting in a similar infiltration depth. Porcelain was coated on the alumina sintered at 1600°C with and without mullite buffer layer. There are no delamination or cracks observed after firing the layered materials. Rod type microstructure and continuous composition are indicated at the interface in the case of the layered structure with mullite buffer layer. To investigate the cracking resistance behavior for this new structure, Vickers indentation and Hertzian contact fatigue tests were conducted. Cracks do not penetrate the interface with mullite buffer layer into the porcelain, showing a reversal case for the layered structure without mullite buffer layer. The layered structure with mullite buffer layer shows higher critical load for fracture than that without mullite buffer layer. Fracture mode of the layered structures in cyclic fatigue shows a top layer (porcelain) fracture at relatively low load (P = 250 N) and higher cycles (n = 106), and a bottom layer (alumina) fracture at higher load (P = 300 N) and relatively low cycles (n = 105).
Using a gas mixture of propyne (C3H4) and ammonia (NH3) as a carbon precursor, we have successfully synthesized multiwalled carbon nanotubes (CNTs) by the direct current (dc) plasma enhanced chemical vapor deposition (PECVD) onto Co-sputtered glass at 550°C. As the flow ratio of NH3 to C3H4 in the mixture gas increased, the crystallinity and alignment of CNTs were improved. In addition, the field emission characteristics of CNTs were also improved. the turn-on voltage became lower, and the current density and the field enhancement factor were more increasing. Raman spectroscopy and scanning electron microscopy were utilized to confirm the effect of the gas flow ratio on CNTs. Therefore, the gas flow ratio was found to be one of important factors to govern the crystalline and field emission characteristics of CNTs. The growth mechanism of CNTs using a C3H4 gas is under investigation with the possibility that three carbon atoms in a C3H4 molecule is converted directly to a hexagon of a CNT by combining two molecules.
Although a number of functional imaging studies are in agreement in suggesting orbitofrontal and subcortical hyperfunction in the pathophysiology of obsessive–compulsive disorder (OCD), the structural findings have been contradictory.
To investigate grey matter abnormalities in patients with OCD by employing a novel voxel-based analysis of magnetic resonance images.
Statistical parametric mapping was utilised to compare segmented grey matter images from 25 patients with OCD with those from 25 matched controls.
Increased regional grey matter density was found in multiple cortical areas, including the left orbitofrontal cortex, and in subcortical areas, including the thalamus. On the other hand, regions of reduction were confined to posterior parts of the brain, such as the left cuneus and the left cerebellum.
Increased grey matter density of frontal–subcortical circuits, consonant with the hypermetabolic findings from functional imaging studies, seems to exist in patients with OCD, and cerebellar dysfunction may be involved in the pathophysiology of OCD.
Tin oxide has been proposed as a promising alternative anode material for microbatteries. It has been reported that its theoretical volumetric capacity is four times larger than that of carbon-based materials, while its gravimetric capacity is twice as large. In this experiment, optimal Si and Bi doped SnO2 films were prepared with e-beam evaporation to improve both the cycle performance and the reversible capacity. The films with addition of Si only exhibited reductions in aggregation of tin particles and formation of micro-cracks. However, there still remained cracks, which induce capacity loss during cycling. To improve capacity retention, Bi was added with Si to SnO2 films, which exhibited the highest reversible capacity of 200µAh/cm2-µm at 200th cycle. The films doped with Bi and Si were found to be ill-defined and featureless without noticeable particle aggregation and cracks. However, the films that underwent cycling tests showed again aggregated tin particles and formation of cracks, which would induce cell failure during cycling. We believe that some types of Li-Bi phases as mixed-conductor matrices have improved the cycle life.
The Far-ultraviolet IMaging Spectrograph (FIMS) is a small spectrograph optimized for the observations of diffuse hot interstellar medium in far-ultraviolet wavebands (900–1150Å and 1335–1750Å). The instrument is expected to be sensitive to emission line fluxes an order of magnitude fainter than any previous missions. FIMS is currently under development and is scheduled for launch in 2002.
Adenoid hypertrophy is known as the most common cause of nasal obstruction in children; thus, adenoidectomy with, or without, tonsillectomy is one of the most commonly performed surgical procedures in the paediatric population. Although many methods have been suggested, few studies have reported on how to assess adenoid size, pre-operatively. Acoustic rhinometry is an objective technique as well as a non-invasive method, which can be easily used in young children. This study confirmed that acoustic rhinometry is a non-invasive and objective technique for assessing the geometry of the nasal cavity and nasopharynx. Forty children were evaluated using symptomology, two different radiological measurements and acoustic rhinometry; the results were compared with endoscopic findings. Clinical symptoms and A/N ratio measured with Fujioka's method significantly correlated with the endoscopic assessment findings (r = 0.769 and 0.604 respectively). Significant increases in the cross-sectional area and volume of the nasopharynx were observed at the adenoid notch after adenoidectomy (p<0.005 and p<0.005, respectively). Acoustic rhinometry showed a high degree of correlation of which adenoid occupied the nasopharyngeal airway under endoscopic examination (r = 0.771). Thus, the study concluded that acoustic rhinometry can be as good an objective method for measuring adenoid sizes as endoscopy and can be used as one of the pre-operative examination tools for adenoidectomy.