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To explore sea level transgression in low-lying inland areas and its possible influence on prehistoric cultures, we investigated the physical and geochemical features of 20-m-long sedimentary cores from the previously seawater-filled Daesan Basin located in the middle reach of the present Nakdong River in Korea as proxies for seawater transgression deep inland areas due to Holocene sea level rise. Based on the relationships among grain size, total sulfur content (TS%), and carbon/sulfur (C/S) ratio, the first transgressive event was detected at ca. 8500 cal yr BP, caused by seawater influx along the present Nakdong River. Higher TS% (0.8–1%) and interbedded fossil oysters at 8000–6000 cal yr BP indicate marine environments, supporting a paleo-Daesan Bay with water depth of ~10–8 m. The common peaks in TS%, in both inland paleo-Daesan Bay and a present coastal area (Suncheon Bay) in southern Korea (e.g., at 3200 and 4700 cal yr BP), may indicate intervals of higher salinity, which suggests simultaneous responses to changes in sea level or hydroclimate. The duration of marine environment (paleo-Daesan Bay) in the remote inland from ca. 8000–3200 cal yr BP provides an analog for inland paleo-bay studies in East Asia.
Nosocomial transmission of COVID-19 among immunocompromised hosts can have a serious impact on COVID-19 severity, underlying disease progression and SARS-CoV-2 transmission to other patients and healthcare workers within hospitals. We experienced a nosocomial outbreak of COVID-19 in the setting of a daycare unit for paediatric and young adult cancer patients. Between 9 and 18 November 2020, 473 individuals (181 patients, 247 caregivers/siblings and 45 staff members) were exposed to the index case, who was a nursing staff. Among them, three patients and four caregivers were infected. Two 5-year-old cancer patients with COVID-19 were not severely ill, but a 25-year-old cancer patient showed prolonged shedding of SARS-CoV-2 RNA for at least 12 weeks, which probably infected his mother at home approximately 7–8 weeks after the initial diagnosis. Except for this case, no secondary transmission was observed from the confirmed cases in either the hospital or the community. To conclude, in the day care setting of immunocompromised children and young adults, the rate of in-hospital transmission of SARS-CoV-2 was 1.6% when applying the stringent policy of infection prevention and control, including universal mask application and rapid and extensive contact investigation. Severely immunocompromised children/young adults with COVID-19 would have to be carefully managed after the mandatory isolation period while keeping the possibility of prolonged shedding of live virus in mind.
Mental illness among survivors of coronavirus disease 2019 (COVID-2019) during the post-illness period is an emerging and important health issue.
We aimed to investigate the prevalence of mental illness and the associated factors for its development among COVID-2019 survivors.
From 1 January to 4 June 2020, data were extracted from the National Health Insurance Service COVID-19 database in South Korea. Patients with COVID-19 were defined as those whose test results indicated that they had contracted the infection, regardless of disease severity. COVID-19 survivors were defined as those who recovered from the infection. The primary end-point was the development of mental illness, which was evaluated between 1 January and 1 December 2020.
A total 260 883 individuals were included in this study, and 2.36% (6148) were COVID-19 survivors. The COVID-19 survivors showed higher prevalence of mental illness than the control group (12.0% in the COVID-19 survivors v. 7.7% in the control group; odds ratio (OR) = 2.40, 95% CI 2.21–2.61, P < 0.001). Additionally, compared with the control group, the no specific treatment for COVID-19 group (OR = 2.23, 95% CI 2.03–2.45, P < 0.001) and specific treatment for COVID-19 group (OR = 3.27, 95% CI 2.77–3.87, P < 0.001) showed higher prevalence of mental illness among survivors.
In South Korea, COVID-19 survivors had a higher risk of developing mental illness compared with the rest of the populations. Moreover, this trend was more evident in COVID-19 survivors who experienced specific treatment in the hospital.
Atomically sharpened tips have attracted much interest in the imaging and manufacturing fields due to their high spatial resolutions. Typically, tungsten (W) is mainly used as the material of such a tip, but when the W tip is used in an oxygen environment, a limit is revealed due to corrosiveness stemming from a reaction with the oxygen gas. To solve this problem, methods of depositing a metal on W that does not react with oxygen have been studied. In this study, we introduce a method of depositing iridium (Ir) directly onto an insulating layer without an additional pretreatment to remove the insulating layer remaining on the W surface, forming an Ir-nanopyramid structure at the apex of the W tip by field evaporation and faceting. Field ion microscopy and atom probe tomography were used to analyze the crystal structure and composition at the apex during the faceting process, and the overall tip shape change after faceting was compared and analyzed with transmission electron microscopy. The proposed method does not have a tip heating step when creating an atomically sharp tip such that it can be made easily with a simpler equipment configuration than in the existing method.
We aim to determine the association between Fe status and the metabolic syndrome (MetS) during menopause. Records of 1069 premenopausal and 703 postmenopausal Korean women were retrieved from the database of the fifth Korean National Health and Nutrition Examination Survey (KNHANES V 2012) and analysed. The association between the MetS and Fe status was performed using multivariable-adjusted analyses, subsequently develop a prediction model for the MetS by margin effects. We found that the risk of Fe depletion among postmenopausal women was lower than premenopausal women (PR = 0·813, 95 % CI 0·668, 0·998, P = 0·038). The risk of the MetS was 2·562-fold lower among premenopausal women with than without Fe depletion (PR = 0·390, 95 % CI 0·266, 0·571, P < 0·001). In contrast, the risk of the MetS tended to be higher among postmenopausal women with than without Fe depletion (PR = 1·849, 95 % CI 1·406, 2·432, P < 0·001). When the serum ferritin levels increased, the risk of the MetS increased in both premenopausal women and postmenopausal women. The margin effects showed that an increase in serum Hb and ferritin was associated with an increase in the risk of the MetS according to menopausal status and age group. Therefore, ferritin is the most validated and widely used Fe marker, could be a potential clinical value in predicting and monitoring the MetS during menopause. Further prospective or longitudinal studies, especially, clinically related studies on menopause and Fe status, are needed to clarify the causality between serum ferritin levels and the MetS that could offer novel treatments for the MetS.
This article reviews the advancements and prospects of liquid cell transmission electron microscopy (TEM) imaging and analysis methods in understanding the nucleation, growth, etching, and assembly dynamics of nanocrystals. The bonding of atoms into nanoscale crystallites produces materials with nonadditive properties unique to their size and geometry. The recent application of in situ liquid cell TEM to nanocrystal development has initiated a paradigm shift, (1) from trial-and-error synthesis to a mechanistic understanding of the “synthetic reactions” responsible for the emergence of crystallites from a disordered soup of reactive species (e.g., ions, atoms, molecules) and shape-defined growth or etching; and (2) from post-processing characterization of the nanocrystals’ superlattice assemblies to in situ imaging and mapping of the fundamental interactions and energy landscape governing their collective phase behaviors. Imaging nanocrystal formation and assembly processes on the single-particle level in solution immediately impacts many existing fields, including materials science, nanochemistry, colloidal science, biology, environmental science, electrochemistry, mineralization, soft condensed-matter physics, and device fabrication.
The study aims to examine whether cognitive deficits are different between patients with early stage Alzheimer's disease (AD) and patients with early stage vascular dementia (VaD) using the Korean version of the CERAD neuropsychological battery (CERAD-K-N).
Patients with early stage dementia, global Clinical Dementia Rating (CDR) 0.5 or 1 were consecutively recruited among first visitors to a dementia clinic, 257 AD patients and 90 VaD patients completed the protocol of the Korean version of the CERAD clinical assessment battery. CERAD-K-N was administered for the comprehensive evaluation of the neuropsychological function.
Of the total 347 participants, 257 (69.1%) were AD group (CDR 0.5 = 66.9%) and 90 (21.9%) were VaD group (CDR 0.5 = 40.0%). Patients with very mild AD showed poorer performances in Boston naming test (BNT) (P = 0.028), word list memory test (P < 0.001), word list recall test (P < 0.001) and word list recognition test (WLRcT) (P = 0.006) than very mild VaD after adjustment of T score of MMSE-KC. However, the performance of trail making A (TMA) was more impaired in VaD group than in AD group. The performance of WLRcT (P < 0.001) was the worst among neuropsychological tests within AD group, whereas TMA was performed worst within VaD group.
Patients with early-stage AD have more cognitive deficits on memory and language while patients with early-stage VaD show worse cognitive function on attention/processing speed. In addition, as the first cognitive deficit, memory dysfunction comes in AD and deficit in attention/processing speed in VaD.
Disclosure of interest
The authors have not supplied their declaration of competing interest.
This research examined gender variations in depressive mood for high school students affected by emotional upset and how such depressive mood affect their sleep quality.
Research was conducted from September 2015 to October 2015. Both males and females were divided into normal group and depressive group by Zung Self-rating Depression Scale (ZSDS). Each group adopted the Pittsburgh Sleep Quality Index (PSQI) to measure sleep quality.
Analysis was made on a total of 155 students, which were 83 male students and 72 female. The average ZSDS for all high school students was 43.38 and the average PSQI was 5.39. The number of male students in the normal and depressive group who were diagnosed with sleep disorder were 2 (3.8%) and 9 (29.0%), respectively (P < 0.05). But the number of female students in the normal and depressive group who were diagnosed with sleep disorder were 11 (32.4%) and 33 (86.8%), respectively (P < 0.05). Both males and females shared a meaningful result over sleep latency, sleep disturbance, use of sleep medication, and daytime functional disturbance among 7 items of PSQI for sleep quality, and female students had a significantly meaningful result over sleep duration, habitual sleep effects (P < 0.05).
This research showed that sleep quality of all high school students was not too bad but it can be problematic for those with depressive mood. Especially, female students were diagnosed with sleep disorder more than male students.
Disclosure of interest
The authors have not supplied their declaration of competing interest.
The international guideline for treating depression has been widely used.
The current study focused on the maintenance treatment section of the third revision of Korean Medication Algorithm for Depressive Disorder (KMAP-DD)
A 44-item questionnaire was used to obtain the consensus of experts regarding pharmacological treatment strategies for depressive disorder. Of the 144 committee members, 79 psychiatrists responded to the survey. Each treatment strategy or treatment option was evaluated with the nine-point scale.
Most clinicians answered to maintain both antidepressants (AD) and atypical antipsychotics (AAP) for psychotic depression in remission state. The duration of AD maintenance: from 19.8 weeks to 46.8 weeks for patients in remission of the first episode, from 34.8 weeks to 78.4 weeks for the second depressive episode, and long-term continuation for three or more depressive episodes. Aripiprazole was the most preferred AAP. The preferred doses of AD and AAP in maintenance treatment were about 75% and 50% of those in acute treatment The maintenance of AAP in the psychotic depression in remission was similar to the AD, although shorter and less.
The maintenance strategies of KMAP-DD 2017 were similar to those of KMAP-DD 2012. Most clinicians preferred to maintain AD for substantial duration after achieving remission. The maintenance of AAP was also preferred, but the duration was shorter than AD.
Disclosure of interest
The authors have not supplied their declaration of competing interest.
The experiments reported in this research paper aimed to determine the effect of supplementing different forms of L-methionine (L-Met) and acetate on protein synthesis in immortalized bovine mammary epithelial cell line (MAC-T cells). Treatments were Control, L-Met, conjugated L-Met and acetate (CMA), and non-conjugated L-Met and Acetate (NMA). Protein synthesis mechanism was determined by omics method. NMA group had the highest protein content in the media and CSN2 mRNA expression levels (P < 0.05). The number of upregulated and downregulated proteins observed were 39 and 77 in L-Met group, 62 and 80 in CMA group and 50 and 81 in NMA group from 448 proteins, respectively (P < 0.05). L-Met, NMA and CMA treatments stimulated pathways related to protein and energy metabolism (P < 0.05). Metabolomic analysis also revealed that L-Met, CMA and NMA treatments resulted in increases of several metabolites (P < 0.05). In conclusion, NMA treatment increased protein concentration and expression level of CSN2 mRNA in MAC-T cells compared to control as well as L-Met and CMA treatments through increased expression of milk protein synthesis-related genes and production of the proteins and metabolites involved in energy and protein synthesis pathways.
Serotonergic dysfunction may play an important role in motor and nonmotor symptoms of Parkinson’s disease (PD). The loudness dependence of auditory evoked potentials (LDAEP) has been used to evaluate serotonergic activity. Therefore, this study aimed to determine central serotonergic activity using LDAEP in de novo PD according to the age at onset and changes in serotonergic activity after dopaminergic treatment.
A total of 30 patients with unmedicated PD, 16 in the early-onset and 14 in the late-onset groups, were enrolled. All subjects underwent comprehensive neurological examination, laboratory tests, the Unified Parkinson’s Disease Rating Scale, and LDAEP. The LDAEP was calculated as the slope of the two N1/P2 peaks measured at the Cz electrode, first at baseline conditions (pretreatment) and a second time after 12 weeks (post-treatment) following dopaminergic medications.
The absolute values of pretreatment N1/P2 LDAEP (early-onset: late-onset, 0.99 ± 0.68: 1.62 ± 0.88, p = 0.035) and post-treatment N1 LDAEP (early-onset: late-onset, −0.61 ± 0.61: −1.26 ± 0.91, p = 0.03) were significantly lower in the early-onset group compared with those of the late-onset group. In addition, a higher value of pretreatment N1/P2 LDAEP was significantly correlated with the late-onset group (coefficient = 1.204, p = 0.044). The absolute value of the N1 LDAEP decreased after 12 weeks of taking dopaminergic medication (pretreatment: post-treatment, −1.457 ± 1.078: −0.904 ± 0.812, p = 0.0018).
Based on the results of this study, LDAEP could be a marker for serotonergic neurotransmission in PD. Central serotonergic activity assessed by LDAEP may be more preserved in early-onset PD patients and can be altered with dopaminergic medication.
The objective of this study is to investigate the effects of trade barriers and cultural distance on the domestic market share in the film industry. We analyze panel data with both two-stage least squares and instrumental-variable methods. These methods can separate the effects of time-invariant measures of trade barriers and cultural difference from country-specific effects. This improvement in the estimation method and the use of a more appropriate measure of trade barriers in the film industry enable us to produce empirical results that are consistent with theoretical arguments. Based on the panel data collected from 30 countries for the period 2001–2013, the empirical results herein indicate that the cultural distance, as well as market size, is an important factor for the domestic market share. Trade barriers are also shown to be a significant factor, but the magnitude of their impact on the domestic market share is much smaller than that of the market size.
Overcrowding in the emergency department (ED) has been a global problem for a long time, but it is still not resolved.
To determine if an ED expansion would be effective in resolving overcrowding.
This was a retrospective study comparing two 10-month periods before (September 2015 to June 2016) and after (September 2017 to June 2018) the ED expansion in an urban tertiary hospital. The existing ED consisted of 45 beds in the adult area and eight beds in the pediatric area. After the construction, the number of beds was not increased, but a fast track area was newly established in the adult area, and a 25-bed ward for emergency hospitalized patients was opened.
The number of patients visiting the ED increased from 77,078 to 87,927. The proportion of patients who returned home without treatment significantly decreased from 11.5% to 0.9% (p<0.001). The number of adult patients increased from 40,814 to 60,720, but the number of patients who could be treated on the bed decreased (22,166 (54.3%) vs. 17,776 (29.3%), p<0.001). The number of pediatric patients was similar in both periods. Median ED length of stay (LOS) of total patients increased from 193.0 min to 205.8 min (p<0.001). Of the 18,900 hospitalized patients during post-period, 1,255 (6.64%) were admitted to the emergency ward, and the boarding (from admission decision to hospitalization) time of the admitted patients decreased from 239.2 min in the pre-period to 190.9 min in the post-period by 38.3 min. However, more time was required for admission decision in the post-period (216.8 vs. 253.3, p<0.001).
The ED expansion allowed more patients to be treated, and the emergency ward reduced boarding times of admitted patients. However, due to the increase in the number of patients, the time required for medical treatment increased.
This study aimed to determine the relationship between laryngopharyngeal reflux and dietary modification.
A systematic review was conducted. The data sources for the study were PubMed, Embase, Cochrane Library and Web of Science. Articles were independently extracted by two authors according to inclusion and exclusion criteria. The outcome focus was laryngopharyngeal reflux improvement through diet or dietary behaviour.
Of the 372 studies identified, 7 met our inclusion criteria. In these seven studies, laryngopharyngeal reflux symptoms improved following dietary modifications. However, the studies did not present the independent effect of each dietary factor on laryngopharyngeal reflux. Moreover, only one of the seven studies had a randomised controlled study design.
The reference studies of dietary modification for laryngopharyngeal reflux patients are not sufficient to provide recommendations.
Scholars often assume that reference groups are industry-wide, homogeneous, and stable. We examine this assumption and suggest hypotheses based on managers’ motivations such as self-enhancement and self-improvement, social identity, and affiliation-based impression management. We test hypotheses on failure-induced changes in reference groups and their direction in terms of upward and downward comparisons. An empirical examination of changes in reference groups for firms listed on the Dow Jones Industrial Average Index between 1993 and 2008 shows that performance below social aspirations induces changes in reference groups and toward upward comparisons. The results indicate that managers can choose to change the reference group – a cognition-centered response – as an alternative to such action-centered responses as organizational search and risk-taking in response to poor performance from social aspirations and that upward comparisons may be the result of social performance shortfalls to give a better impression and to improve firm performance.
The ferroelectricity in fluorite-structure oxides such as hafnia and zirconia has attracted increasing interest since 2011. They have various advantages such as Si-based complementary metal oxide semiconductor-compatibility, matured deposition techniques, a low dielectric constant and the resulting decreased depolarization field, and stronger resistance to hydrogen annealing. However, the wake-up effect, imprint, and insufficient endurance are remaining reliability issues. Therefore, this paper reviews two major aspects: the advantages of fluorite-structure ferroelectrics for memory applications are reviewed from a material's point of view, and the critical issues of wake-up effect and insufficient endurance are examined, and potential solutions are subsequently discussed.