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To evaluate the appropriateness of the screening strategy for healthcare personnel (HCP) during a hospital-associated Middle East Respiratory Syndrome (MERS) outbreak, we performed a serologic investigation in 189 rRT-PCR–negative HCP exposed and assigned to MERS patients. Although 20%–25% of HCP experienced MERS-like symptoms, none of them showed seroconversion by plaque reduction neutralization test (PRNT).
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 hardness changes caused by formation of the metastable and stable phases were examined and correlated with the microstructural changes in grain interior and grain boundary during aging at 350 °C to clarify the age-hardening and softening mechanism of a low-gold Au-Cu-Ag-Pd dental alloy. Aging in this context refers to the time-delay that occurs wherein such alloys are kept at elevated temperatures for periods upto many hours to allow precipitation or ordering to take place. During the period of increasing hardness, the matrix was separated into the Ag-rich α1 and AuCu I phases through the metastable phases, forming block-like structure. The apparent hardening was attributed primarily to lattice strain due to the tetragonality of AuCu I′ [the primer (′) here indicates a metastable phase; likewise (I) and (I′) indicate stable AuCu I and metastable AuCu I′ phases, respectively] and AuCu I phases along the c-axis, secondarily to the coherency or semicoherency strain between the metastable α1′ and AuCu I′ phases and between the α0 and AuCu I phases along the a-axis. The apparent softening was caused primarily by growth and coarsening of the lamellar structure in the grain boundaries, secondarily by coarsening of the block-like structure in the grain interior.
Vitamin D insufficiency is known to be related to cardiometabolic disorders; however, the associations among serum 25-hydroxyvitamin D (25(OH)D) concentration and metabolic syndrome and cardiometabolic risk factors in children and adolescents have not yet been clearly delineated. For this reason, we investigated the relationship among serum 25(OH)D concentration and metabolic syndrome and cardiometabolic risk factors among Korean adolescents.
We performed a cross-sectional analysis and used hierarchical multivariate logistic regression analysis models to adjust for confounding variables.
We used the data gathered during the 2008–2009 Korea National Health and Nutrition Examination Survey (KNHANES).
Our subjects included 1504 Korean adolescents aged 12–18 years who participated in the KNHANES.
Vitamin D insufficiency, defined as 25(OH)D concentration <50 nmol/l, was found in 75·3 % of Korean adolescents and was associated with an increased risk of the prevalence of metabolic syndrome. Waist circumference and BMI were the most closely correlated cardiometabolic components of metabolic syndrome according to serum 25(OH)D status, but no significant relationship was found between serum 25(OH)D concentration and insulin resistance or for the risks for high blood pressure, hyperglycaemia, reduced HDL-cholesterol or hypertriacylglycerolaemia, with or without adjustment for confounding variables.
Low serum 25(OH)D concentration appears to be associated with several cardiometabolic risk factors and an increased risk of the prevalence of metabolic syndrome in Korean adolescents.
Web servers have to be protected against overload since overload can lead to a server breakdown, which in turn causes high response times and low throughput. In this paper, a stochastic model for breakdowns of server systems due to overload is proposed and an admission control policy which protects Web servers by controlling the amount and rate of work entering the system is studied. Requests from the clients arrive at the server following a nonhomogeneous Poisson process and each requested job takes a random time to be completed. It is assumed that the breakdown rate of the server depends on the number of jobs which are currently being performed by the server. Based on the proposed model, the reliability function and the breakdown rate function of the server system are derived. Furthermore, the long-run expected number of jobs completed per unit time is derived as the efficiency measure, and the optimal admission control policy which maximizes the efficiency will be discussed.
Intra-uterine growth retardation has been linked to the development of type 2 diabetes in later life. Mitochondrial changes have been suggested as a link between fetal malnutrition and adult insulin resistance. Taurine has been implicated in this process. We investigated whether protein malnutrition in early life alters mitochondria of the pancreatic islets in adulthood, and whether taurine supplementation restores these changes. Male offspring of rats fed a control diet, a low-protein diet or a low-protein diet supplemented with taurine during pregnancy and lactation were weaned onto the control diet. In each group, at 20 weeks of age, intravenous glucose tolerance tests, euglycaemic–hyperinsulinaemic clamp studies, morphometric analysis of the pancreatic islets and ultra-structural analysis of the mitochondria of the β-cells were performed. The expressions of cytochrome c oxidase (COX) I and mitochondrial respiratory chain complex II were also measured. Fetal protein-malnourished rats showed decreased pancreatic islet mass and reduced insulin-secretory responses to a glucose load. These rats also showed reduced mitochondrial DNA-encoded COX I gene expression in the islets. Electron microscopic examination showed abnormal mitochondrial shapes in the β-cells of fetal protein-malnourished rats. Taurine supplementation to the low-protein diet restored all these changes. Our findings indicate that a maternal protein-restriction diet causes long-lasting mitochondrial changes that may contribute to the development of type 2 diabetes later in life. The lack of taurine may be a key causative factor for these dysfunctional mitochondrial changes.
There has been a significant effort to create spiral sensors by changing either the periodic d-spacing of the structure or the dielectric constants of the materials by combining the multi-faceted environmental responsiveness of polymer hydrogels with dielectrical structures.1 Reversible spiral switches with dimensional functionalities that respond to chemical environment were constructed. When the spiral photonic actuator was swollen in hydrophilic acetic acid, right-handed spiral structures are formed, while the spiral photonic actuator was swollen in hydrophobic hexane, left-handed spiral structures are formed. All actuators returned back to the transparent planar state after deswelling processes. These reversible spiral photonic actuators can be applied in the application of mechanical actuators, electrical devices, and optical components.
Accumulated evidence suggests that social support is influenced by genetic and environmental factors. However, there are little data that examine this issue from Asian samples. We reported results from a preliminary study that examined familial effects on social support in a Chinese adult twin sample. We administered a 10-item social support instrument that measures three dimensions of social support (i.e., objective support, subjective support, and utilization of support) developed for the Chinese population. Two hundred forty-two same-sex twin pairs, where both members of the pair completed the personal interview, were included in the final analysis. Structural equation modeling was used to estimate additive genetic (A), shared environmental (C), and nonshared environmental (E) effects on each dimension of social support. Familial factors (A+C) explained 56.63% [95% CI = 45.48–65.72%] and 42.42% [95% CI = 29.93–53.25%] of the total phenotypic variances of subjective support and utilization of support, respectively. For the objective support, genetic effects did not exist, but common environmental effect explained 37.56% [95% CI = 26.17–48.28%] of the total phenotypic variances. Neither gender nor age effects were seen on any dimension of social support. Except for objective support, genetic factors probably influence variation in subjective support and utilization of support. Shared environmental factors may influence all dimensions of social support.
By injecting additional argon gas, we were able to grow one-dimensional ZnO nanorod arrays with a uniform distribution on a large scale at a low temperature of less than 330 °C by metalorganic chemical vapor deposition. All of the nanorods grown on the sapphire substrate had a 30° in-plane rotation with respect to the substrate and showed the epitaxial characteristics of [10¯10]ZnO//[11¯20]sapphire, despite the low-temperature growth. These ZnO nanorods with high crystalline quality exhibited a high enhancement factor and low turn-on field value, thus having good potential to be used as a field emitter.
We introduce a simple preparation method for ultrathin carbon support
films that is especially useful for high-resolution electron microscopy
(HREM) of nanoparticles. Oxidized iron nanoparticles were used as a test
sample in a demonstration of this method. The film qualities are discussed
on the basis of electron-energy-loss spectroscopy (EELS) and image
analysis techniques such as thickness maps and histograms. We carried out
a comparison between the homemade and commercial film qualities. The
relative thickness of the homemade support films was 0.6 times less than
that of the commercial films, which was calculated from the EELS analysis,
whereas the thicknesses of both carbon support films varied within about
3%. The percentage of the observable area was about 67 ± 7.6% of
the support film. This was about twice as large as the commercial film (32
± 9.3%). The HREM image of the sample prepared with our support
film improved 9% in brightness and 15% in contrast compared with images
obtained with the commercial support.
The structural properties of GaN epitaxial layers grown on patterned sapphire substrates by MOCVD have been investigated using HRXRD(high-resolution X-ray diffraction), GIXRD(grazing incidence X-ray diffraction) and PL(photoluminescence). For X-ray characterizations rocking curves for GaN (10·5), (00·2), (11·4) and (11·0) reflections for which incidence angles of X-rays are 32.0°, 17.3°, 11.0° and 0.34°, respectively, were measured. For (10·5), (00·2) and (11·4) reflections FWHMs of the rocking curves for a patterned substrate were broader than those for a unpatterned substrate, for (11·0) reflection, however, FWHM for a patterned substrate was much narrower than that for a unpatterned substrate. The normalized FWHM for all reflections decreases as the incidence angle of X-ray decreases. The results indicate that the crystalline quality in the surface region of the epilayer on a patterned substrate was especially improved because the penetration depth of X-ray depends on the incidence angle. The intensity of PL peak of the epilayer for a patterned substrate increased compared to that for a unpatterned substrate, and the increase in PL intensity is attributed to the reduction in dislocation density at the surface region revealed the by X-ray results.
We investigated whether the perception or production of a given line
length in normal subjects varies according to where in peripersonal
space the line is perceived or produced. We also investigated the
influence of the direction of movement used to make the line. In
Experiment 1, blindfolded normal subjects were asked to estimate
distances while the examiner moved the subject's hand in proximal
(medial) or distal (lateral) space, moving centripetally or
centrifugally. The subjects showed a spatial effect, perceiving the
same length as shorter in proximal space than distal space. This result
could be related to either a proximal spatial attentional bias or an
anisometric representation of spatial distances. In Experiment 2, we
attempted to dissociate these hypotheses by studying blindfolded normal
subjects, who were requested to produce horizontal lines of a given
length (100 or 200 mm) in proximal versus distal peripersonal
space using centripetal or centrifugal movements. Centrifugal movements
in proximal space were the longest; centrifugal movements in distal
space were the shortest; in between were the proximal centripetal and
distal centripetal movements which did not differ from each other.
These results suggest that in peripersonal space the perception of
length in normal subjects is most consistent with anisometric mental
representation where the size of mental representations of length units
decreases as a function of the distance from the subject's
midsagittal plane. Length production, however, may depend on an
interaction of the anisometric mental representation and the
premotor/intentional factors. (JINS, 2004, 10,
Sequential lateral solidification (SLS) is known to be a promising method to make low-temperature poly-Si thin film transistors (LTPS TFTs) with superior performance for fabrication of highly circuit-integrated flat panel displays such as TFT liquid crystal display and TFT organic light-emitting diode. The dependence of TFT characteristics on the details of the SLS poly-Si microstructures was studied by varying the size, direction, and shape of the grains by applying different SLS crystallization mask patterns and processing details. The TFTs results demonstrated that various device properties and characteristics are obtained depending on the specifics of the microstructures. Nearly direction-insensitive TFTs of mobility about 300 cm2/V·s (within 5% variation of average value) were successfully fabricated by controlling the microstructures. Such a characteristic is recognized as being desirable for an optimal integration of the peripheral circuits.
The purpose of this study was to evaluate the effects of botulinum toxin A (BTX-A, Botox) dilution volume and post-injection exercise with electrical stimulation on muscle paralysis. We injected 10 units of BTX-A diluted with 0.1 ml (B1, n=8) or 0.5 ml (B5, n=8) normal saline into both gastrocnemius muscles of 16 New Zealand white rabbits; two controls received no BTX-A. After BTX-A injection, all rabbits received calf muscle stretching exercise and electrical stimulation for 2 hours on the left leg. The compound muscle action potential (CMAP) decrease was most pronounced at 1 week and progressive recovery was observed (i.e. recovery from paralysis, increase of CMAP). There was a significant decrease of CMAP amplitudes in the B5 group compared with the B1 group at week 1 and week 4 (p<0.001). Left limbs with stretching exercise and electrical stimulation showed lower CMAP amplitudes compared with control right limbs of all rabbits. To maximize the muscle paralysis effect of BTX-A, increasing dilution volume and performing post-injection stretching exercise with electrical stimulation may be a promising strategy for increasing the beneficial effect of BTX-A treatment. Future studies are needed to investigate the clinical application of this finding.
Large area, flat panel detectors are being investigated for digital radiogrpahy and fluoroscopy. Theses detectors employ an x-ray conversion layer of photoconductor to detect x-rays. The amorphous selenium layer that is currently being studied for its use as an x-ray photoconductor is not pure a-Se but rather a-Se doped with 0.2-0.5% As and 10-30 ppm Cl, also known as stabilized a-Se. The suitability of the stabilized a-Se is largely determined by its charge on generating, transporting and trapping properties.
In this paper, a conventional time-of-flight measurement was carried out to analyze the transport properties of charge carriers. A laser beam with pulse duration of 5 ns and wavelength of 350 nm was illuminated on the surface of the stabilized a-Se with thickness of 400 μm. The photo response signals of the hole and electron were measured at the applied electric field of 10 V/μm as a function of time. The measured transit times of the hole and electron were about 229.17μs and about 8.73μs at 10 V/μm, respectively. The measured mobility indicated a slight dependence with respect to the applied electric field with a range of 4-10 V/μm. The experimental results showed that the measured mobility of the hole and electron was 0.04584 cm2V-1s-1 and 0.00174 cm2V-1s-1 at the electric field of 10 V/μm.
Nowadays, large area, flat panel solid state detectors are being investigated for digital radiography. In this paper, development and evaluation of a selenium-based flat-panel digital xray detector are described. The prototype detector has a pixel pitch of 139μm and a total active imaging area of 7″×8.5″, giving a total of 1.9 million pixel. This detector include a x-ray imaging layer of amorphous selenium as a photoconductor which is evaporated in vacuum state on a TFT flat panel, to make signals in proportion to incident x-ray. The film thickness was about 500μm. To evaluate the imaging performance of the digital radiography (DR) system developed in our group, sensitivity, linearity of the response of exposure, the modulation transfer function(MTF) and detective quantum efficiency(DQE) of detector was measured. The measured sensitivity was 4.16×106 ehp/pixel mR at the bias field of 10 V/μm: The beam condition was 41.9 KeV. Measured MTF at 2.5 lp/mm was 52%, and the DQE at 1.5 lp/mm was 75%.
Pt/Sr0.85Bi2.4Ta2O9/TiO2/Si structures were prepared with variation of the Sr0.85Bi2.4Ta2O9 (SBT) film thickness for MFIS-FET applications. After depositing TiO2 film of 10 nm thickness by reactive sputtering on Si(100) substrate as a buffer layer, SBT thin film of 210-400 nm thickness was prepared onto it by metal organic decomposition process. Regardless of the SBT film thickness, the Pt/SBT/TiO2/Si structures exhibited clockwise directional hysteresis, indicating well-defined ferroelectric switching behavior of the SBT films. While the memory window of the Pt/SBT/TiO2/Si MFIS structures increased with increasing the SBT film thickness, the maximum capacitance of the Pt/SBT/TiO2/Si MFIS structures decreased with increasing the SBT film thickness. The Pt/SBT(400 nm)/TiO2(10 nm)/Si structure exhibited a memory window of 1.3 V at ±5 V.
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