To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
This is a copy of the slides presented at the meeting but not formally written up for the volume.
Stripe domains in ferroelectric thin films form in order to minimize the total energy of the film. It has been known for some time that a stable configuration is reached when the decrease in elastic energy from domain formation is balanced by the energetic costs of domain wall formation, local elastic strains in the substrate, and internal electric field formation from domain polarizations. The size and strain of each domain is determined by the lattice mismatch and the energetic costs of interface formation. Recent piezoelectric force microscopy measurements have shown that BiFeO3 (BFO) films on SrRuO3/SrTiO3 (001) substrates form striped polarization domains. Since the details of the local structure and polarization cannot be measured at the same time with conventional techniques, we have used synchrotron x-ray microdiffraction to study these effects. Probing only a few domains at a time with the submicron x-ray spot resulted in a diffraction pattern near the substrate (103) reflection consisting of several BFO peaks. We have unambiguously assigned these peaks to individual structural variants. Based on these results, we propose a physical model that includes the striped domains. The structural variants within the stripes are similar to those predicted by striped patterns in rhombohedral films which minimize elastic energy. The local piezoelectric properties were measured using time-resolved microdiffraction in order to examine the role of the striped domains in the linear responses of the film. The out of plane piezoelectric coefficient d33 was approximately 50 pm/V and the piezoelectric strain was proportional to electric field was up to 0.55%, the maximum strain we have measured. The projection of the in-plane piezoelectric coefficients onto the reciprocal space maps for different structural variants had vastly different values due to the differences in orientation of the domains.
Despite the possibility that cognitive deficits associated with depression may have different patterns depending on the level of neurocognitive impairment, there remains no clear evidence of this. This study aimed to investigate the differential association between depression and cognitive function in patients with mild cognitive impairment (MCI) and Alzheimer’s disease (AD).
A cross-sectional analysis was performed of data from 1,724 patients with MCI and 1,247 patients with AD from the Clinical Research Center for Dementia in Korea. Depression was assessed using the Korean form of the Geriatric Depression Scale, and cognition was measured using the Seoul Neuropsychological Screening Battery, which includes five domains (attention, language and related function, visuospatial function, memory, and frontal/executive function).
Significant differences were found between the two groups (non-depressed vs. depressed) in visuospatial, memory, and executive function domains in the MCI group, as well as in the attention domain in the AD group. The association between depressive symptoms and cognitive function was significantly greater in patients with MCI than in those with AD. These associations were more pronounced in memory and executive function.
Our findings suggest that the association between depression and decreased cognitive function is more pronounced in MCI than AD.
We investigated the extent of delays in the response time of emergency medical services (EMS) as an impact of mass casualty incidences (MCIs) in the same area.
We defined an MCI case as an event that resulted in 6 or more patients being transported by EMS, and prehospital response time as the time from the call to arrival at the scene. We matched patients before and after MCIs by dividing them into categories of 3 hours before, 0-1 hour after, 1-2 hours after, and 2-3 hours after the MCIs. We compared prehospital response times using multiple linear regression.
A total of 33,276 EMS-treated patients were matched. The prehospital response time for the category of 3 hours before the MCIs was 8.8 minutes (SD: 8.2), treated as the reference, whereas that for the category of 0-1 hour after the MCI was 11.3 minutes (P<0.01). The multiple linear regression analysis revealed that prehospital response time increased by 2.5 minutes (95% CI: 2.3-2.8) during the first hour and by 0.3 minutes (95% CI: 0.1-0.6) during the second hour after MCIs.
There were significant delays in the prehospital response time for emergency patients after MCIs, and it lasted for 2 hours as the spillover effect. (Disaster Med Public Health Preparedness. 2018;12:94–100)
Despite their importance in the formation and evolution of stellar clusters and galaxies, the formation of high-mass stars remains poorly understood. We recently started a systematic observational study of the 22 GHz water and 44 GHz class I methanol masers in high-mass star-forming regions as a four-year KaVA large program. Our sample consists of 87 high-mass young stellar objects (HM-YSOs) in various evolutionary phases, many of which are associated with two or more different maser species. The primary scientific goals are to measure the spatial distributions and 3-dimensional velocity fields of multiple maser species, and understand the dynamical evolution of HM-YSOs and their circumstellar structures, in conjunction with follow-up observations with JVN/EAVN (6.7 GHz class II methanol masers), VERA, and ALMA. In this paper we present details of our KaVA large program, including the first-year results and observing/data analysis plans for the second year and beyond.
We present the results of the linear polarisation observations of methanol masers at 44 and 95 GHz towards 39 massive star forming regions (Kang et al. 2016). These two lines are observed simultaneously with the 21-m Korean VLBI Network (KVN) telescope in single dish mode. About 60% of the observed showed fractional polarisation of a few percents at least at one of the two transition lines. We note that the linear polarisation of the 44 GHz methanol maser is first detected in this study including single dish and interferometer observations. We find the polarisation properties of these two lines are similar as expected, since they trace similar regions. As a follow-up study, we have carried out the VLBI polarisation observations toward some 44 GHz maser targets using the KVN telescope. We present preliminary VLBI polarisation results of G10.34-0.14, which show consistent polarisation properties in multiple epoch observations.
Echinochloa species are among the most troublesome weeds in
rice cultivation, and grow in a broad habitat range in Korea. Although
various ecotypes of Echinochloa have been collected as
germplasm for future studies, it has been difficult to classify them due to
their high level of morphological similarity. This study was thus conducted
to develop and investigate the phylogenetic relationships between 77
Echinochloa accessions with the use of 23 simple
sequence repeat (SSR) markers and 24 morphological traits. Of 77
Echinochloa accessions, including 57 accessions from
Korea and 5 reference species, late watergrass was clearly clustered as a
distinctive group from barnyardgrass and other Echinochloa
species. In this analysis, we also identified core genetic and morphological
markers that can be used for the future identification and classification of
Echinochloa species. Five out of 23 SSR makers produced
distinctive bands that discriminate late watergrass from barnyardgrass and
other Echinochloa species. Four morphological traits of the
reproductive organs were the most influential contributors for classifying
Echinochloa species. Although there was no clear
consensus generated in this study between SSR markers and morphological
trait analyses, our results support the potential use of the selected SSR
markers and morphological traits in future studies of
We report a simple and scalable process to synthesize the core–shell
nanostructure of MoS2@N-doped carbon nanosheets (MoS2@C),
in which polydopamine is coated on the MoS2 surface and then
carbonized. Transmission electron microscopy reveals that the as-synthesized
MoS2@C possesses a nanoscopic and ultrathin layer of
MoS2 sheets with a thin and conformal coating of carbon layers
(∼5 nm). The MoS2@C demonstrates a superior
electrochemical performance as an anode material for lithium ion batteries
compared to exfoliated MoS2 sample. This unique core–shell
structure is capable of excellent delivery of Li+ ion in
charging–discharging process: a specific capacity as high as 1239 mA
h g−1, a high rate of charging-discharging capability even
at a high current rate of 10 A g−1 while retaining 597 mA
h g−1, and a good cycle stability over 70 cycles at a high
current rate of 2 A g−1.
A cylindrical-shaped micropillar array embedded microfluidic device was proposed to enhance the dispersion of cell clusters and the efficiency of single cell encapsulation in hydrogel. Different sizes of micropillar arrays act as a sieve to break Escherichia coli (E. coli) aggregates into single cells in polyethylene glycol diacrylate (PEGDA) solution. We applied the external force for the continuous breakup of cell clusters, resulting in the production of more than 70% of single cells into individual hydrogel particles. This proposed strategy and device will be a useful platform to utilize genetically modified microorganisms in practical applications.
This study examined changes in health-related quality of life (HRQoL) and quality of care (QoC) as perceived by terminally ill cancer patients and a stratified set of HRQoL or QoC factors that are most likely to influence survival at the end of life (EoL).
We administered questionnaires to 619 consecutive patients immediately after they were diagnosed with terminal cancer by physicians at 11 university hospitals and at the National Cancer Center in Korea. Subjects were followed up over 161.2 person-years until their deaths. We measured HRQoL using the core 30-item European Organization for Research and Treatment of Cancer Quality of Life Questionnaire, and QoC using the Quality Care Questionnaire–End of Life (QCQ–EoL). We evaluated changes in HRQoL and QoC issues during the first three months after enrollment, performing sensitivity analysis by using data generated via four methods (complete case analysis, available case analysis, the last observation carried forward, and multiple imputation).
Emotional and cognitive functioning decreased significantly over time, while dyspnea, constipation, and pain increased significantly. Dignity-conserving care, care by healthcare professionals, family relationships, and QCQ–EoL total score decreased significantly. Global QoL, appetite loss, and Eastern Cooperative Oncology Group Performance Status (ECOG–PS) scores were significantly associated with survival.
Significance of results:
Future standardization of palliative care should be focused on assessment of these deteriorated types of quality. Accurate estimates of the length of life remaining for terminally ill cancer patients by such EoL-enhancing factors as global QoL, appetite loss, and ECOG–PS are needed to help patients experience a dignified and comfortable death.
Miscanthus is a promising bioenergy crop due to its high productivity and broad environmental adaptability to tropical and temperate climates. As important Miscanthus species such as M. sinensis and M. sacchariflorus are native to East Asia, implying more diverse Miscanthus genetic resources in this region, in this study, we collected about 300 Miscanthus accessions from East Asia, mainly in Korea. From the whole collections, 66 Miscanthus accessions representing geographical location and latitude were selected and tested through a 3-year field trial to investigate genetic diversity in their agronomic traits. Five agronomic traits associated with biomass production were assessed to investigate the relationships of agronomic traits with biomass yield and latitudes of locations where Miscanthus accessions were collected. Plant height, stem diameter, stem dry weight and heading date exhibited a significantly positive correlation with biomass yield with r= 0.465, 0.780, 0.817 and 0.450, respectively. Stem diameter (r= − 0.495), stem dry weight (r= − 0.393), heading date (r= − 0.914) and estimated yield (r= − 0.425) exhibited a significantly negative correlation with latitudes of the collection sites. The results of the study revealed the existence of considerable genetic diversity in agronomic traits in the Miscanthus accessions collected. The presence of a significant relationship between latitudes and agronomic traits suggests that accessions collected from different geographical latitudes will provide more genetically diverse materials for breeding. Therefore, the results of the present study can provide useful information and materials for Miscanthus breeding programmes.
Postural instability is one of the most disabling features of Parkinson's disease, usually occurring in late and advanced stages. The aim of this study was to investigate the postural performance of early-stage de novo Parkinson's disease patients with no clinical postural instability using computerized dynamic posturography. We sought to understand the relationship between postural sway and disease severity and the relationship between postural instability quantitatively measured by computerized dynamic posturography and cognitive impairment in early-stage Parkinson's disease patients.
Thirty-one subjects with Parkinson's disease and 20 healthy controls were assessed by the computerized dynamic posturography protocol using the sensory organization test and the motor control test. A neuropsychological assessment was also administered.
The mean equilibrium score for sensory organization test and the vestibular input ratio were significantly correlated with Hoehn-Yahr stage. No associations between motor latency for any motor control test condition and Hoehn-Yahr stage were found. The equilibrium score for sensory organization test correlated with the mini-mental status examination scores. There was a significant correlation between motor latency for large backward translation and mini-mental status examination scores. There were significant correlations between visual perception/construction/ memory of the neuropsychological battery test and the equilibrium score for sensory organization test and between verbal word learning test, controlled word association test and motor latency for large backward translation.
These findings showed the postural instability present in early-stage (Hoehn-Yahr stage 2-2.5) Parkinson's disease. We also found a close relationship between postural instability and cognitive function in Parkinson's disease patients.
We have carried out simultaneous 22 GHz H2O and 44 GHz Class I CH3OH maser line surveys of more than 1500 intermediate- and high-mass YSOs in the Galaxy using newly-constructed KVN 21-m telescopes. As the central (proto)stars evolve, the detection rates of the two masers rapidly decrease for intermediate-mass YSOs while the rates increase for high-mass YSOs. These results suggest that the occurrence of the two masers is closely related both to the evolutionary stage of the central objects and to the circumstellar environments. CH3OH masers always have very similar velocities (<10 km s−1) to the natal dense cores, whereas H2O masers often have significantly different velocities. The isotropic luminosities of both masers are well correlated with the bolometric luminosities of the central (proto)stars.
Morphology of foliar trichomes was analyzed in Quercus variabilis by electron microscopy and three-dimensional surface profiling. Leaves from suppressed or dominant sprouts of the oak species were collected after a forest fire to unravel the effects of the disturbance factor on sprouting of the oak species. Scanning electron microscopy revealed two types of trichomes depending on the leaf surface. The trichomes on the adaxial surface were branched and constricted, and possessed a single row of thin-walled cells with a collapsed morphology (glandular branched uniseriate trichomes). Meanwhile, the trichomes on the abaxial surface were star-shaped, unfused with each other, and had 6 to 10 rays (nonglandular simple stellate trichomes). An apparent proliferation of trichomes was evident on the adaxial surface of the dominant sprouts. Uniseriate trichomes could be discernable as an elevation from the surface by white light scanning interferometry. By transmission electron microscopy, thin and convoluted cell wall, degenerated cytoplasm, and a single row of cells were characteristic of the trichomes on the adaxial surface. The thick cell walls of the mature trichomes on the abaxial surface represented the nonglandular nature. This is the first report on the morphological and ultrastructural characterization of foliar trichomes of the oak species.
This paper compared two different film deposition processes for formation of TiN barrier layers, conventional TiCl4-based chemical vapor deposition and atomic layer deposition (ALD). The 30nm thick TiN film deposited by conventional TiCl4-based CVD at the process temperature of 600°C followed by NH3 post-deposition anneal showed about 180 μΩcm of resistivity, over 95 % of step coverage for the pattern aspect ratio of 6 on 0.35 μm contact diameters, and below 2 at.% of chlorine contents in the film. Meanwhile, the films deposited by ALD at 100°C lower process temperature than CVD showed much better film properties even without post-deposition anneal. It showed lower resistivity values and lower chlorine incorporation along with better step coverage characteristics. More detailed material analysis was done by AFM, SEM, and AES.
The melting of the semicrystalline poly(ethylene oxide)(PEO)/ poly(ε -caprolactone) (PCL) multiblock copolymer was investigated by small and wide angle x-ray scattering. The two-stage melting was found in which the PEO block and the PCL block melt independently. The crystalline PEO Bragg peaks disappear at 30.5 °C while the block spacing increases due to the chain relaxation. The PEO crystalline domain size decreases continuously in proportion to the amount of the crystalline part. Above 40 °C, the PCL lamellae domains started to melt and the integrated intensity of the PCL Bragg peak decreases with increasing temperature. In the case of the PCL, however, the crystal domain size decreases only slightly. This indicates that the number of the PCL crystalline domains decreases during the melting.
Processible poly(methylsilsesquioxane)s (PMSSQs) were prepared in THF solution under nitrogen atmosphere in the presence of HCl catalyst. It was found that various reaction parameters such as concentration, temperature, reaction time, the amount of water, and the amount of acid catalyst could affect the molecular weight and the amount of functional end groups of PMSSQ samples. Thin films prepared from our PMSSQ samples by spin-coating followed by curing to 420°C exhibited a much better crack resistance than those presented in the literature, while the dielectric constant remained practically the same, i.e., ca. 2.7.
We propose a mesh-type PECVD to minimize the hydrogen concentration in this study. Since in this system deposition rate is very slow, so for increasing a deposition rate, we suggest an applied DC bias enhanced sputtering process. We investigated several conditions to compare with conventional PECVD. Excimer-laser melting and regrowth of thin a-Si films is for fabricating polycrystalline-Si (poly-Si). Furthermore, we fabricate poly-Si thin-film transistor(TFTs) and measure threshold voltage (V), field-effect mobility (cm2 /Vs) and on/off current ratio
Silica slurry used as abrasives in wafer polishing process is made by dispersing silica particles in an alkali solution. Since commercially available colloidal or fumed silica particles need some modifications to be directly used as abrasive slurry due to their small sizes, irregular shapes or broad size distribution, we have prepared silica abrasives by particle growth of fumed silica or colloidal silica as seeds by sol-gel method. Silica slurries prepared by this step-wise growth from commercial seeds were tested using one-armed polisher for the comparison with commercial slurries and showed the performance comparable to commercial slurries. Microstructures of polishing slurries were investigated using transmission electron microscopy and ARES rheometer. From the result, stability of the slurry was found to be more important than the primary particle sizes for the polishing performance.
When an electric field is applied to a ferroelectric the crystal lattice spacing changes as a result of the converse piezoelectric effect. Although the piezoelectric effect and polarization switching have been investigated for decades there has been no direct nanosecond-scale visualization of these phenomena in solid crystalline ferroelectrics. Synchrotron x-rays allow the polarization switching and the crystal lattice distortion to be visualized in space and time on scales of hundreds of nanometers and hundreds of picoseconds using ultrafast x-ray microdiffraction. Here we report the polarization switching visualization and polarization domain wall velocities for Pb(Zr0.45Ti0.55)O3 thin film ferroelectric capacitors studied by time-resolved x-ray microdiffraction.