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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.
The aim of this study is to develop predictive models to predict organ at risk (OAR) complication level, classification of OAR dose-volume and combination of this function with our in-house developed treatment decision support system.
Materials and methods
We analysed the support vector machine and decision tree algorithm for predicting OAR complication level and toxicity in order to integrate this function into our in-house radiation treatment planning decision support system. A total of 12 TomoTherapyTM treatment plans for prostate cancer were established, and a hundred modelled plans were generated to analyse the toxicity prediction for bladder and rectum.
The toxicity prediction algorithm analysis showed 91·0% accuracy in the training process. A scatter plot for bladder and rectum was obtained by 100 modelled plans and classification result derived. OAR complication level was analysed and risk factor for 25% bladder and 50% rectum was detected by decision tree. Therefore, it was shown that complication prediction of patients using big data-based clinical information is possible.
We verified the accuracy of the tested algorithm using prostate cancer cases. Side effects can be minimised by applying this predictive modelling algorithm with the planning decision support system for patient-specific radiotherapy planning.
Personality may predispose family caregivers to experience caregiving differently in similar situations and influence the outcomes of caregiving. A limited body of research has examined the role of some personality traits for health-related quality of life (HRQoL) among family caregivers of persons with dementia (PWD) in relation to burden and depression.
Data from a large clinic-based national study in South Korea, the Caregivers of Alzheimer's Disease Research (CARE), were analyzed (N = 476). Path analysis was performed to explore the association between family caregivers’ personality traits and HRQoL. With depression and burden as mediating factors, direct and indirect associations between five personality traits and HRQoL of family caregivers were examined.
Results demonstrated the mediating role of caregiver burden and depression in linking two personality traits (neuroticism and extraversion) and HRQoL. Neuroticism and extraversion directly and indirectly influenced the mental HRQoL of caregivers. Neuroticism and extraversion only indirectly influenced their physical HRQoL. Neuroticism increased the caregiver's depression, whereas extraversion decreased it. Neuroticism only was mediated by burden to influence depression and mental and physical HRQoL.
Personality traits can influence caregiving outcomes and be viewed as an individual resource of the caregiver. A family caregiver's personality characteristics need to be assessed for tailoring support programs to get the optimal benefits from caregiver interventions.
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.
Psychological health is an important issue after disasters. This study aimed to investigate the prevalence of psychological symptoms among 993 residents of Taean District in South Korea after the Hebei Spirit oil spill and to examine determinants of vulnerability in residents’ psychological symptoms.
Symptoms of post-traumatic stress (PTS), depression, suicidal ideation, and anxiety were assessed by questionnaires, and the responses were analyzed by using the survey analysis considering the sampling frame.
Among the study subjects, the symptom prevalences of PTS, depression, suicidal ideation, and anxiety were 19.5%, 22.0%, 2.3%, and 4.2%, respectively, and symptoms were higher in people who were female, were older, were less educated, and had lower family income. People with fishery or related occupations compared to those with unrelated livelihoods and people residing in the vicinity of the oil band in the contaminated coastline showed additively increased symptom risks of PTS. Risk of suicidal ideation was predominantly increased in people with fishery or related occupations compared with those with unrelated livelihoods.
Social supports, including compensation for income loss and community mental health programs, and longer follow-up studies are needed for residents in the communities affected by the Hebei Spirit oil spill. (Disaster Med Public Health Preparedness. 2016;10:51-58)
This article aims to provide an understanding of the dynamics of pension politics in South Korea with a particular focus on the role of bureaucrats. In order to explain the reforms, this research will closely examine how the expertise and legitimacy of civil servants, together with their institutional positioning, have affected their power and role in the policy-making process. This article will argue that bureaucrats, particularly the welfare bureaucracy, attained their major reform goals by associating and competing with other political actors in two major reforms.
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.
Background: Highly educated participants with normal cognition show lower incidence of Alzheimer's disease (AD) than poorly educated participants, whereas longitudinal studies involving AD have reported that higher education is associated with more rapid cognitive decline. We aimed to evaluate whether highly educated amnestic mild cognitive impairment (aMCI) participants show more rapid cognitive decline than those with lower levels of education.
Methods: A total of 249 aMCI patients enrolled from 31 memory clinics using the standard assessment and diagnostic processes were followed with neuropsychological evaluation (duration 17.2 ± 8.8 months). According to baseline performances on memory tests, participants were divided into early-stage aMCI (−1.5 to −1.0 standard deviation (SD)) and late-stage aMCI (below −1.5 SD) groups. Risk of AD conversion and changes in neuropsychological performances according to the level of education were evaluated.
Results: Sixty-two patients converted to AD over a mean follow-up of 1.43 years. The risk of AD conversion was higher in late-stage aMCI than early-stage aMCI. Cox proportional hazard models showed that aMCI participants, and late-stage aMCI participants in particular, with higher levels of education had a higher risk of AD conversion than those with lower levels of education. Late-stage aMCI participants with higher education showed faster cognitive decline in language, memory, and Clinical Dementia Rating Sum of Boxes (CDR-SOB) scores. On the contrary, early-stage aMCI participants with higher education showed slower cognitive decline in MMSE and CDR-SOB scores.
Conclusions: Our findings suggest that the protective effects of education against cognitive decline remain in early-stage aMCI and disappear in late-stage aMCI.
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.
We have observed the inconsistent findings from various studies on twin pregnancy outcomes obtained by assisted reproductive technology and spontaneous conception. In most studies, however, the concrete chorionicity, regarded as a confounding factor for predicting the perinatal outcomes of twin pregnancies, has not been determined. The purpose of this study was to compare obstetric and perinatal outcomes of only the dichorionic twin pregnancies according to the methods of conception: spontaneous and in-vitro fertilization (IVF). The twin pairs with dichorionicity reported from 1995 to 2008 were investigated and we divided them into two groups which consisted of 286 and 134 twins by spontaneous conception and IVF, respectively. Odds ratios for associations between IVF and pregnancy outcomes were analyzed after adjustment for maternal age and parity. There were no risk differences between the two groups regarding the obstetric complications, which include preterm delivery, preterm labor, preterm premature rupture of membranes, preeclampsia, placenta previa, and abruption. Any differences were not shown in the two groups for the risk estimates of perinatal outcomes, such as low birthweight, very low birthweight, small for gestational age, Apgar scores of < 7 at 5 minutes, discordance in birthweights, congenital anomalies and mortality. However, twins conceived after IVF were less likely to be admitted to the neonatal intensive care unit than those conceived spontaneously (adjusted OR 0.488; 95% confidence interval 0.261–0.910). In the cases of dichorionic twins, IVF may not be associated with adverse perinatal and obstetric outcomes compared with spontaneous conception.
A new species, Arthula biformis Oh and Lee sp. nov., belonging to the cryptine ichneumonid subtribe Sphecophagina Beirne is described from Korea. The new species is composed of two seasonal forms, overwintering and summer, distinguished by color and some morphological features. The overwintering form is much darker than the summer form. Keys to the genera of Sphecophagina and the known species of Arthula Cameron and photographs of diagnostic characters of both color forms of the new species are provided.
This paper reports the results of tree-ring dating and accelerator mass spectrometry (AMS) wiggle-matching for wooden Buddhist statues stored at the Eungjindang Hall of Neunggasa Temple, South Korea. Among 23 statues, 10 were successfully dated by tree rings. The cutting date of logs used for the statues was determined as some time between late fall 1684 and early spring 1685 when the bark ring (AD 1684) completed latewood formation. The 95.4% confidence interval of a radiocarbon date (cal AD 1688–1713, 2 σ), which was obtained by wiggle-matching 7 samples of a statue, is similar to the dendro-date (AD 1684). A historical document recorded that the statues in the Eungjindang of Neunggasa were dedicated in July 1685. The dendro-date and written record indicate that Eungjindang statues were made within 3–8 months after log cutting. This seems rather short if we consider the period required for natural drying to avoid defects such as cracking and crooking.
To determine the appropriateness of antibiotic prophylaxis regimens for major surgery in Korea.
Retrospective study using a written survey for each patient who underwent arthroplasty, colon surgery, or hysterectomy.
Six tertiary hospitals in Seoul and Gyeonggi Province.
From each hospital, a maximum of 150 patients who underwent each type of surgery were randomly chosen for the study.
Of 2,644 eligible patients, 1,914 patients were included in the analysis; 677 of these patients underwent arthroplasty, 578 underwent colon surgery, and 659 underwent hysterectomy. Nineteen patients were excluded from the analyses of the class and number of antibiotics used for prophylaxis because they underwent multiple surgeries at different sites. For each of the 1,895 remaining patients, antibiotic prophylaxis involved a mean ( ± SD) of 2.8 ± 0.9 classes of antibiotics. The most commonly prescribed agents were cephalosporins (prescribed for 1,875 [98.9%] of the patients) and aminoglycosides (1,404 [74.1%]). A total of 1,574 (83.1%) of patients received at least 2 classes of antibiotics simultaneously. Only 15 (0.8%) of 1,895 patients received antibiotic prophylaxis in accordance with published guidelines. Of 506 patients for whom the initial dose of antibiotics was evaluated, 374 (73.9%) received an appropriate initial dose. Of the 1,676 patients whose medical records included information about antibiotic administration relative to the time of surgery, only 188 (11.2%) received antibiotic prophylaxis an hour or less before the surgical incision was made. Of the 1,748 patients whose medical records included information about duration of surgery, antibiotic prophylaxis was discontinued 24 hours or less after surgery for only 3 (0.2%) of the patients.
Most patients who had major surgery in Korea received inappropriate antibiotic prophylaxis. Measures to improve the appropriateness of antibiotic prophylaxis are urgently required.
ZnO nanorods were synthesized by a hot-wall type pulsed laser ablation process. At temperatures 500∼800°C, ZnO thin films and wrinkles were synthesized. Above 800°C, vertically aligned ZnO nanorods were grown on the Si and sapphire substrate without any catalysts. The range of diameter was 100∼300nm. When Au catalyst were deposited on the substrate prior to the deposition, the process range of ZnO nanorod become wider and the diameter of ZnO narrower. Especially, ZnO could be grown selectively along the pattern of Au catalyst with the aid of Au-Zn alloy.
Until now, little was known about the mode of parotid involvement in external auditory canal (EAC) carcinoma. The incidence of parotid node metastasis and direct parotid invasion was examined in patients with EAC carcinoma. The study comprised 11 patients with squamous cell carcinomas (SCC) and 10 patients with adenoid cystic carcinomas (ACC). A retrospective review of the surgical specimens was undertaken with specific reference to parotid node metastasis and parotid invasion. Parotid node metastasis was noted only in two cases of advanced staged SCC, whereas none of the ACC patients showed parotid node metastasis. Direct parotid invasion occurred only in advanced staged SCC,however, it did occur in early stage ACC. Our data indicated that elective parotidectomy for control of occult parotid node metastasis is necessary only in advanced SCC carcinoma, whereas parotid management to secure adequate safety margins is mandatory for advanced SCC and all cases of ACC.
The internal stress distribution in multilayer actuator was analyzed by a numerical simulation. Around the edge of conventional inter-digital electrodes, the non-uniform electric field generated the stress concentration, which caused the ceramic to crack. Various electrode configurations were presented to decrease this stress concentration. Especially the float electrode type is a promising design because this can be fabricated using almost the same process as the conventional multilayer actuator, and the simulated results indicted that the float electrode type decreased the stress concentration of inter-digital type in approximately 1/3.
The grain morphology of the intermetallic compound (IMC) that forms at the interface between liquid solders and solid-metal substrates was observed at solder joints. Cu6Sn5 grains on Cu substrates were rough or rounded, and Ni3Sn4 grains on Ni substrates were faceted. Through the energy-based calculations, the relationship between the IMC grain morphology and Jackson's parameter α was explained. The Jackson's parameter of the IMC grain with a rough surface is smaller than 2 while it is larger than 2 for faceted grains.
In this letter, we investigated the correlation between as-grown surface morphologies and Mn compositions of Ga1-xMnxAs epilayers - a III-V diluted magnetic semiconductor - grown by liquid phase epitaxy (LPE). Ga1-xMnxAs epilayers were grown at 595 °C from 50 % Ga + 50 % Bi mixed solvent. The grown layers were characterized by energy dispersive x-ray analysis (EDS) and atomic forced microscopy (AFM). The Mn composition measured by EDS after growth process was varied from 1 to 7 %. As increasing Mn composition surface morphologies of as-grown Ga1-xMnxAs epilayers were varied. At higher Mn compositions, the morphology of the surface layers degrades strongly, preventing removal of the solution-melt from it. Key words: LPE, as-grown, surface morphology, Mn composition, Ga1-xMnxAs, energy-dispersive x-ray analysis (EDS), atomic forced microscopy (AFM).
Sources for low frequency noise in polycrystalline silicon thin-film transistors are analytically investigated. The grain boundary is modeled as symmetric Schottky barrier and a new device equation for current conduction in thin-film transistors is presented. At lower currents where barrier height is large enough to provide necessary distribution of time constants for 1/f noise, the number fluctuation via barrier height modulation at the grain boundary is found to be the main noise generation mechanism. At higher currents, mobility and diffusivity fluctuation are found to be dominant
This paper presents a new
recursive algorithm of robot dynamics based on the Kane's dynamic
equations and Newton-Euler formulations. Differing from Kane's work, the algorithm
is general-purpose and can be easily realized on computers. It
is suited not only for robots with all rotary joints
but also for robots with some prismatic joints. Formulations of
the algorithm keep the recurrence characteristics of the Newton-Euler formulations,
but possess stronger physical significance. Unlike the conventional algorithms, such
as the Lagrange and Newton-Euler algorithm, etc., the algorithm can
be used to deal with dynamics of robots containing closed
chains without cutting the closed chains open. In addition, this
paper makes a comparison between the algorithm and those conventional
algorithms from the number of multiplications and additions.