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A growing number of Korean adolescents consume energy drinks, which may increase the risk of obesity, anxiety, and insomnia. We examined whether poor sleep was associated with energy drink consumption among study participants.
We used a cross-sectional design.
The Korea Youth Risk Behavior Web-Based Survey data from 2019.
To determine the association between sleep and energy drink consumption, we compared the independent variables for 50,455 adolescents in Korea (aged 14–19 years) using multivariate logistic regression and sensitivity analyses.
In Korea, 69.5% adolescents consumed energy drinks, 17.1% slept for less than five hours, 22.4% slept for 5–6 hours, 23.8% slept for 6–7 hours, 19.9% slept for 7–8 hours, and 16.7% slept for eight hours or more. Regarding sleep satisfaction, 21.0% reported sufficient, 32.6% reported just enough, while 46.5% reported insufficient. Regarding sleep duration, it was found that less than five hours (OR, 2.36; 95% CI, 2.14–2.60) and lower sleep satisfaction (OR, 1.12; 95% CI, 1.03‒1.21) were highly associated with energy drink consumption, with statistical significance at p<0.05. Adolescents with lower sleep duration (aOR, 6.37; 95% CI, 4.72‒8.61) and a lack of sleep satisfaction (aOR, 1.44; 95% CI, 1.16‒1.78) reported drinking a high amount of energy drinks, that is,at least once a day.
In addition to efforts to decrease the amount of energy drinks consumed, sleep hygiene education needs to be strengthened.
Under the potential to reconstruct the past climatic and atmospheric conditions from a deep ice core in the coastal Antarctic site (Styx Glacier), an 8.84 m long firn core (73°50.975′ S, 163°41.640′ E; 1623 m a.s.l.) was initially studied to propose a reliable age scale for the local estimation of snow accumulation rate. The seasonal variations of δ18O, methanesulfonic acid (MSA) and non-sea-salt sulfate (nssSO42–) were used for the firn core dating and revealed 25 annual peaks (from 1990 to 2014) with volcanic sulfate signal. The observed declining trend in annual accumulation rate with a mean value of 146 ± 60 kg m–2 a–1 is likely to be linked to the changes of sea-ice extent in the Ross Sea region. Moreover, the temporal variation of the annual mean δ18O, an annual flux of MSA and nssSO42– also likely to be under the influence of ice-covered and open water area. This study suggests a potential to recover past changes in an oceanic environment and will be useful for the interpretation of the long ice core drilled at the same site.
Although neurocognitive dysfunction and physical performance are known to be impaired in patients with schizophrenia, evidence regarding the relationship between these two domains remains insufficient. Thus, we aimed to investigate the relationship between various physical performance domains and cognitive domains in individuals with schizophrenia, while considering other disorder-related clinical symptoms.
Sixty patients with schizophrenia participated in the study. Cardiorespiratory fitness and functional mobility were evaluated using the step test and supine-to-standing (STS) test, respectively. Executive function and working memory were assessed using the Stroop task and Sternberg working memory (SWM) task, respectively. Clinical symptoms were evaluated using the Brief Psychiatric Rating Scale, Beck Depression Inventory, and State-Trait Anxiety Inventory. Multivariate analyses were performed to adjust for relevant covariates and identify predictive factors associated with neurocognition.
Multiple regression analysis revealed that the step test index was most strongly associated with reaction time in the Stroop task (β = 0.434, p = 0.001) and SWM task (β = 0.331, p = 0.026), while STS test time was most strongly associated with accuracy on the Stoop task (β=−0.418, p = 0.001) and SWM task (β=−0.383, p = 0.007). Total cholesterol levels were positively associated with Stroop task accuracy (β=−0.307, p = 0.018) after controlling for other clinical correlates. However, clinical symptoms were not associated with any variables in Stroop or SWM task.
The present findings demonstrate the relationship between physical performance and neurocognition in patients with schizophrenia. Considering that these factors are modifiable, exercise intervention may help to improve cognitive symptoms in patients with schizophrenia, thereby leading to improvements in function and prognosis.
Predicting the isotopic modification of ice by melting processes is important for improving the accuracy in paleoclimate reconstruction. To this end, we present results from cold room laboratory observations of changes in the isotopic ratio (D/H and 18O/16O) of ice cubes by isotopic exchange between liquid water and ice in nearly isothermal conditions. A 1-D model was fit to the isotopic results by adjusting the values of two parameters, the isotopic exchange rate constant (kr) and the fraction of ice participating in the exchange (f). We found that the rate constant for hydrogen isotopic exchange between liquid water and ice may be greater (up to 40%) than that for the oxygen isotopic exchange. The range of the rate constant obtained from four melt experiments is from 0.21 to 0.82 h–1. The model results also suggest that f decreases with the increasing wetness of the ice. This is because with increasing water saturation in ice, water may be present only in the small pores or some of the water that was exchanged with ice may be bypassed, decreasing the effective surface area over which the isotopic exchange can occur. The relationship between the two water isotopes (δ18O vs δD) was observed and modeled and the slope was <8, which is significantly different from the slope of the meteoric waterline. We note that these slopes were obtained without considering the sublimation process.
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.
We investigated the electrical conduction and resistance switching mechanisms of TiOx thin films grown on three kinds of bottom electrode at room temperature (an inert Pt, an active Ti and fluorine tin oxide FTO electrodes). The bottom electrode materials strongly affect the I-V characteristics and switching parameters. The I-V characteristic is explained through the presence of interface states in the metal electrode devices (Pt and Ti) and the work function in the metal oxide device (FTO). The Pt device has the smallest VSET and largest switching ratio, while the Ti device shows the largest VSET and smallest switching ratio. XPS data shows non-lattice oxygen in TiOx films. Therefore, the proposed bipolar resistance switching arises from formation and rupture of filament paths, generated by the movement of oxygen vacancies. All devices depict the same electrical conductions, trap-controlled space-charge-limited, FN tunneling and Ohmic conductions for a high resistance state and a low resistance state, respectively. In this study, the rarely reported FN tunneling conduction in published TiOx-based ReRAM device was found, which can be attributed to an influence of the bottom electrode on the electronic distribution in devices.
The liquid phase plasma reduction method has been applied to prepare silver nanoparticles from a solution of silver nitrate (AgNO3) using a bipolar pulsed electrical discharge system. The excited states of atomic silver, hydrogen and oxygen as well as the molecular bands of hydroxyl radicals were detected in the emission spectra. As the discharge duration increased up to 10 min, silver particle peaks produced by surface plasmon absorption were observed around 430 nm. Both the particle size and the particle numbers were observed to increase with the length of the plasma treatment time and with the initial AgNO3 concentration. Spherical nanoparticles of about 5–20 nm in size were obtained with the discharging time of 5 min, whereas aggregates of nanoparticles of about 10–50 nm in size were mainly produced with the discharging time of 20 min. The cationic surfactant of cetyltrimethylammonium bromide (CTAB) added with the CTAB/AgNO3 molar ratio of 30% was shown to inhibit nanoparticle aggregation.
The oxidation behavior of Cu50Zr50 and Cu46Zr46Al8 glasses during continuous heating up to 1073 K has been investigated, with special emphasis on the oxidation resistance in the supercooled liquid (SCL) state. For Cu50Zr50, the oxide layer mostly consists of monoclinic ZrO2 (m-ZrO2), while for Cu46Zr46Al8, the oxide layer consists of two different layers: an outer layer consisting of tetragonal ZrO2 (t-ZrO2) + Al2O3 + metallic Cu (oxidation product from the SCL state of the glass matrix) and inner layer comprised of m-ZrO2 + metallic Cu islands (oxidation product from the crystallized matrix). Cu-enriched regions consisting of Cu51Zr14 (in Cu50Zr50) or AlCu2Zr + Cu70Zr15Al15 + Cu51Zr14 (in Cu46Zr46Al8) are present below the oxide layer. The present study shows that the addition of Al (8 at.%) in Cu50Zr50 results in a significant deterioration of the oxidation resistance in the SCL state since the solutionizing of Al in t-ZrO2 leads to a higher oxygen ion vacancy concentration, thus providing a higher activity of oxygen ions.
To investigate the annual rate of tuberculosis (TB) infection among newly employed nurses using both tuberculin skin test (TST) and QuantiFERON-TB Gold (QFT-G; Cellestis Limited) assay.
A prospective cohort study involving newly employed nurses.
A tertiary care university hospital in South Korea.
All participants (n = 196) were tested with the TST and QFT-G assay at baseline. After 1 year, the TST and QFT-G assay were reperformed for subjects who had negative TST results at baseline and for all subjects, respectively.
The baseline TST and QFT-G assays were positive for 101 subjects (51.5%) and 28 subjects (14.3%), respectively; 22 subjects (11.2%) had positive results of both tests. Although the overall between-test agreement was 54.9% (κ = 0.151 [95% confidence interval, 0.047–0.245]), agreement improved to 78.5% (κ = 0.462 [95% confidence interval, 0.007–0.917]) for subjects who had not received bacille Calmette-Guérin vaccination. After 1 year, the TST yielded positive results for 16 (21.3%) of 75 nurses with negative baseline results, and the QFT-G assay yielded positive results for 21 (14.4%) of 146 subjects with negative baseline Results. Collectively, 5 subjects (3.0%) experienced conversion to positive results with both tests, and 32 subjects (18.9%) experienced conversion to positive results with one of the tests. Neither the employing hospital department nor exposure to patients with TB affected test conversion status.
The poor overall agreement between TST and QFT-G results may have been caused by the confounding effect of bacille Calmette-Guérin vaccination. The annual risk of TB infection among newly employed nurses was at least 3% on the basis of results of both the TST and QFT-G test. Stricter preventive strategies against TB spread should be implemented in our hospital.
The Yonsei-Yale Isochrones have been widely used since its birth in 2001. We announce a major upgrade mainly making varieties of helium values available. The recent works on the globular clusters with extreme helium abundances have called for such a need. The new version of the Y2 Isochrones are available for [α/Fe] = 0 through 0.6, ΔY/ΔZ = 1.5 through 3.0, and extreme helium abundances (Y = normal 0.05, 0.1, 0.15, 0.2), and for 11 metallicity grids, with full capability of interpolation. The database will be powerful for making population models. Besides, the accuracy of the models on the lower main sequence has been substantially improved. We illustrate the major upgrades and demonstrate the power of the new grids.
This paper gives a necessary and sufficient condition for a Kuhn-Tucker point of a non-smooth vector optimisation problem subject to inequality and equality constraints to be an efficient solution. The main tool we use is an alternative theorem which is quite different to a corresponding result by Xu.
Incomplete reprogramming of the donor cell nucleus after nuclear transfer (NT) probably leads to the abnormal expression of developmentally important genes. This may be responsible for the low efficiency of cloned animal production. Insulin-like growth factor 2 (IGF2) and IGF2 receptor (IGF2R) are imprinted genes that play important roles in preimplantation development. To obtain an insight into abnormal gene expression after nuclear transfer, we assessed the transcription patterns of IGF2-IGF2R in single in vitro fertilised and cloned embryos by reverse-transcription polymerase chain reaction (RT-PCR). IGF2R expression did not differ significantly but IGF2 was more highly expressed in cloned embryos than in IVF embryos (p < 0.05). This was confirmed by a quantitative RT-PCR method. Thus, incomplete reprogramming may induce abnormal transcription of IGF2 in cloned embryos.
The sliding friction and wear performance of Al–Ni–Co–Si quasicrystalline coatings deposited by the high-velocity oxy-fuel technique were investigated under dry sliding conditions. This study indicated that changes in the imposed sliding test conditions modified the friction and wear behavior of quasicrystalline coatings. Qualitative analysis of the contact interface and wear debris were performed with the aim of understanding the role of the third body on the friction and wear processes. The dependence of the coefficient of friction on the sliding velocity and counterpart material was explained by the stick-slip behavior. It was also shown that test conditions favorable for the formation of thick intermediate layers and the densification of the coating subsurface led to low wear rates. Large cylindrical particles, formed by agglomeration of small wear debris, were suggested as a beneficial factor for the reduction of the coefficient of friction.
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.
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