Gender differences in the effect of comorbid insomnia symptom on depression, anxiety, fatigue, and daytime sleepiness in patients with obstructive sleep apnea.

PURPOSE: This study investigated gender differences in the effect of comorbid insomnia symptom on depression, anxiety, fatigue, daytime sleepiness, and quality of life in patients with obstructive sleep apnea. There are gender differences in the presentation of obstructive sleep apnea. However, the influence of gender on the presentation of comorbid insomnia symptom and obstructive sleep apnea is not known. METHODS: Allparticipantsperformed overnightpolysomnography and completed a battery of questionnaires including Beck Depression Inventory, State-Trait Anxiety Inventory, Multidimensional Fatigue Inventory, Epworth Sleepiness Scale, and Short Form-36 Health Survey. Insomnia symptom was defined as present if a patient had any insomnia complaints longer than 1 month and at least one time per week. RESULTS: Six hundred fifty-five adult patients with obstructive sleep apnea were enrolled; 233 (35.5 %) reported comorbid insomnia symptom with obstructive sleep apnea. The severity of obstructive sleep apnea was not related to comorbid insomnia symptom. Based on linear regression, women had higher depression, fatigue, and daytime sleepiness and lower health-related quality of life than men (all, p<0.05). The presence of insomnia symptom had negative effects on fatigue (p=0.005) and quality of life only (p=0.015) in men but not in women when taking gender-by-insomnia interaction into consideration. There were significant differences in polysomnography-based sleep architecture between the obstructive sleep apnea-only and obstructive sleep apnea-insomnia groups, but only in the subgroup of men. CONCLUSIONS: Men are more prone to the negative impact of comorbid insomnia symptom and obstructive sleep apnea on their level of fatigue and quality of life than women.

Polarization-selective four-wave mixing in a degenerate multi-level system.

This paper describes the first observation of polarization-selective four-wave mixing signals in conventional coupling-probe spectroscopy, specifically, saturation absorption spectroscopy in 85Rb atoms. The four-wave mixing signal is induced by two counter-propagating laser beams in a degenerate multi-level atomic system, involving the F g = 3 → F e = 2 , 3 , and 4 transitions of the 85Rb D2 line. Consequently, the four-wave mixing signals copropagating along the probe beam induce polarization rotation of a linearly polarized probe beam. To distinguish these four-wave mixing signals from the resulting probe beam, we detect the polarization components orthogonal to the polarization direction of the input probe beam, depending on the linear polarization angles between the probe and coupling beams. The experimental findings demonstrate excellent agreement with theoretical results.

Dynamic polarization response of polarization-maintaining fibers by periodic thermal cycling method.

We report a periodic thermal cycling method to investigate the dynamic response of the polarization of a laser propagating through polarization-maintaining (PM) optical fiber, driven by periodic weak temperature modulation. Consequently, temperature modulation on the surface of the coating material of the PM fiber was found to cause a continuous periodic change in the polarization state of the output laser without approaching the steady state of the resulting dynamic polarization response. Additionally, the response was found to depend on the temperature-modulation frequency and amplitude. These experimental results are qualitatively in good agreement with that of the simple theoretical model. Our research would be applied not only to the method of measuring properties of a PM optical fiber by utilizing the continuous modulation of the differential refractive index with a wide modulation-frequency range but also to various applications of the dynamic control of the periodic refractive index in materials.

Aligned structures of mesogenic motifs in epoxy resin and their thermal conductivities.

The epoxy-based crosslinked polymer with the mesogenic group has been studied as a candidate resin material with high thermal conductivity due to the ordered structure of the mesogenic groups. In this study, we conducted all atomic molecular dynamics simulations with iterative crosslinking procedures on various epoxy resins with mesogenic motifs to investigate the effect of molecular alignment on thermal conductivity. The stacked structure of aromatic groups in the crosslinked polymer was analyzed based on the angle-dependent radial distribution function (ARDF), where the resins were categorized into three groups depending on their monomer shapes. The thermal conductivities of resins were higher than those of conventional polymers due to the alignment of aromatic groups, but no distinct correlation with the ARDF was found. Therefore, we conducted a further study about two structural factors that affect the alignment and the TC by comparing the resins within the same groups: the monomer with an alkyl spacer and functional groups in hardeners. The alkyl chains introduced in the epoxy monomers induced more stable stacking of aromatic groups, but thermal conductivity was lowered as they inhibited phonon transfer on the microscopic scale. In the other case, the functional groups in the hardener lowered the TC when the polar interaction with other polar groups in the monomer was strong enough to compete with the pi-pi interaction. These results represent how various chemical motifs in mesogenic groups affect their alignment on the atomistic scale, and also how they have effects on the TC consequently.

Reduction and oxidation of oxide ion conductors with conductive atomic force microscopy.

Local accumulation and dissipation of charges on the surface of oxide ion conductors resulting from electric potentials were observed with conductive atomic force microscopy (AFM). After a negative bias was applied at the tip, a sequence of surface potential maps appeared compatible with electron injection onto the electrolyte surface. Applying a positive bias, in contrast, generated a positive surface charge adjacent to the tip contact area. This observation is consistent with the formation of oxide ion vacancies on the oxide surface. In addition, oxide ion conductivity at a low temperature range (100-200 degrees C) was obtained, and the activation energy for diffusion in gadolinia-doped ceria (GDC) was calculated as approximately 0.56 eV, implying that the majority of oxide ion vacancies diffuse on the surface rather than inside the bulk of the electrolyte.

Motion-Programmed Bar-Coating Method with Controlled Gap for High-Speed Scalable Preparation of Highly Crystalline Organic Semiconductor Thin Films.

Solution-processed organic semiconductor thin films with high charge carrier mobility are necessary for development of next-generation electronic applications, but the rapid processing speed demanded for the industrial-scale production of these thin films poses a challenge to control of their thin-film properties, such as crystallinity, morphology, and film-to-film uniformity. Here, we show a new solution coating method that is compatible with a roll-to-roll printing process at a rate of 2 mm s-1 by using a gap-controllable wire bar, motion-programming strategy, and blended active inks. We demonstrate that the coating bar, the horizontal motion of which is repeatedly brought to an intermittent standstill, results in an improved vertically self-stratified structure and a high crystallinity for organic active inks comprising a semiconducting small molecule and a semiconducting polymer. Furthermore, organic transistors prepared by the developed method show superior hole mobility with high operational stability (hysteresis and kink-free transfer characteristics), high uniformity over a large area of a 4 in. wafer, good reproducibility, and superior electromechanical stabilities on a flexible plastic substrate. The bar-coating approach demonstrated here will be a step toward developing industrial-scale practical organic electronics applications.

A Plesiohedral Cellular Network of Graphene Bubbles for Ultralight, Strong, and Superelastic Materials.

Advanced materials with low density and high strength impose transformative impacts in the construction, aerospace, and automobile industries. These materials can be realized by assembling well-designed modular building units (BUs) into interconnected structures. This study uses a hierarchical design strategy to demonstrate a new class of carbon-based, ultralight, strong, and even superelastic closed-cellular network structures. Here, the BUs are prepared by a multiscale design approach starting from the controlled synthesis of functionalized graphene oxide nanosheets at the molecular- and nanoscale, leading to the microfluidic fabrication of spherical solid-shelled bubbles at the microscale. Then, bubbles are strategically assembled into centimeter-scale 3D structures. Subsequently, these structures are transformed into self-interconnected and structurally reinforced closed-cellular network structures with plesiohedral cellular units through post-treatment, resulting in the generation of 3D graphene lattices with rhombic dodecahedral honeycomb structure at the centimeter-scale. The 3D graphene suprastructure concurrently exhibits the Young's modulus above 300 kPa while retaining a light density of 7.7 mg cm-3 and sustaining the elasticity against up to 87% of the compressive strain benefiting from efficient stress dissipation through the complete space-filling closed-cellular network. The method of fabricating the 3D graphene closed-cellular structure opens a new pathway for designing lightweight, strong, and superelastic materials.

Multidisciplinary Approach to Decrease In-Hospital Delay for Stroke Thrombolysis.

BACKGROUND AND PURPOSE: Decreasing the time delay for thrombolysis, including intravenous thrombolysis (IVT) with tissue plasminogen activator and intra-arterial thrombectomy (IAT), is critical for decreasing the morbidity and mortality of patients experiencing acute stroke. We aimed to decrease the in-hospital delay for both IVT and IAT through a multidisciplinary approach that is feasible 24 h/day. METHODS: We implemented the Stroke Alert Team (SAT) on May 2, 2016, which introduced hospital-initiated ambulance prenotification and reorganized in-hospital processes. We compared the patient characteristics, time for each step of the evaluation and thrombolysis, thrombolysis rate, and post-thrombolysis intracranial hemorrhage from January 2014 to August 2016. RESULTS: A total of 245 patients received thrombolysis (198 before SAT; 47 after SAT). The median door-to-CT, door-to-MRI, and door-to-laboratory times decreased to 13 min, 37.5 min, and 8 min, respectively, after SAT implementation (P<0.001). The median door-to-IVT time decreased from 46 min (interquartile range [IQR] 36-57 min) to 20.5 min (IQR 15.8-32.5 min; P<0.001). The median door-to-IAT time decreased from 156 min (IQR 124.5-212.5 min) to 86.5 min (IQR 67.5-102.3 min; P<0.001). The thrombolysis rate increased from 9.8% (198/2,012) to 15.8% (47/297; P=0.002), and the post-thrombolysis radiological intracranial hemorrhage rate decreased from 12.6% (25/198) to 2.1% (1/47; P=0.035). CONCLUSIONS: SAT significantly decreased the in-hospital delay for thrombolysis, increased thrombolysis rate, and decreased post-thrombolysis intracranial hemorrhage. Time benefits of SAT were observed for both IVT and IAT and during office hours and after-hours.

Production of various disinfection byproducts in indoor swimming pool waters treated with different disinfection methods.

In this study, the concentrations of disinfection byproducts (DBPs), including trihalomethanes (THMs; chloroform, bromodichloromethane, dibromochloromethane, and bromoform), haloacetic acids (HAAs; dichloroacetic acid and trichloroacetic acid), haloacetonitriles (HANs; dichloroacetonitrile, trichloroacetonitrile, bromochloroacetonitrile, and dibromoacetonitrile), and chloral hydrate (CH) were measured in 86 indoor swimming pools in Seoul, Korea, treated using different disinfection methods, such as chlorine, ozone and chlorine, and a technique that uses electrochemically generated mixed oxidants (EGMOs). The correlations between DBPs and other environmental factors such as with total organic carbon (TOC), KMnO(4) consumption, free residual chlorine, pH, and nitrate (NO(3)(-)) in the pools were examined. The geometric mean concentrations of total DBPs in swimming pool waters were 183.1±2.5µg/L, 32.6±2.1µg/L, and 139.9±2.4µg/L in pools disinfected with chlorine, ozone/chlorine, and EGMO, respectively. The mean concentrations of total THMs (TTHMs), total HAAs (THAAs), total HANs (THANs), and CH differed significantly depending on the disinfection method used (P<0.01). Interestingly, THAAs concentrations were the highest, followed by TTHMs, CH, and THANs in all swimming pools regardless of disinfection method. TOC showed a good correlation with the concentrations of DBPs in all swimming pools (chlorine; r=0.82, P<0.01; ozone/chlorine; r=0.52, P<0.01, EGMO; r=0.39, P<0.05). In addition, nitrate was positively correlated with the concentrations of total DBPs in swimming pools disinfected with chlorine and ozone/chlorine (chlorine; r=0.58; ozone/chlorine; r=0.60, P<0.01), whereas was negative correlated with the concentrations of total DBPs (r=-0.53, P<0.01) in the EGMO-treated pools.

A resolution study for electrostatic force microscopy on bimetallic samples using the boundary element method.

Electrostatic force microscopy (EFM) is a special design of non-contact atomic force microscopy used for detecting electrostatic interactions between the probe tip and the sample. Its resolution is limited by the finite probe size and the long-range characteristics of electrostatic forces. Therefore, quantitative analysis is crucial to understanding the relationship between the actual local surface potential distribution and the quantities obtained from EFM measurements. To study EFM measurements on bimetallic samples with surface potential inhomogeneities as a special case, we have simulated such measurements using the boundary element method and calculated the force component and force gradient component that would be measured by amplitude modulation (AM) EFM and frequency modulation (FM) EFM, respectively. Such analyses have been performed for inhomogeneities of various shapes and sizes, for different tip-sample separations and tip geometries, for different applied voltages, and for different media (e.g., vacuum or water) in which the experiment is performed. For a sample with a surface potential discontinuity, the FM-EFM resolution expression agrees with the literature; however, the simulation for AM-EFM suggests the existence of an optimal tip radius of curvature in terms of resolution. On the other hand, for samples with strip- and disk-shaped surface potential inhomogeneities, we have obtained quantitative expressions for the detectability size requirements as a function of experimental conditions for both AM- and FM-EFMs, which suggest that a larger tip radius of curvature is moderately favored for detecting the presence of such inhomogeneities.