Flat Barrier Research Articles

Body Fit With a Pouching System With Concave Contour for People With an Outward Peristomal Body Profile: Effects on Leakage, Wear Time, and Quality of Life: A Randomized Controlled Cross-Over Trial.

The purpose of the study was to investigate the fit of a two-piece pouching system with a concave-shaped skin barrier on people with an outward peristomal body profile and its effect on leakage, wear time, and quality of life (QoL) related to using an ostomy product. Randomized, controlled, open-label, cross-over trial. The sample comprised 53 subjects with outward peristomal body profiles and problems with leakage of ostomy effluent from their pouching system. Participants were randomized to the concave two-piece pouching system or a comparator (two-piece pouching system with a flat skin barrier) for 3 weeks. Subjects were then crossed over to the opposite skin barrier for an additional 3 weeks. The study was conducted in Denmark, Norway, Germany, and the Netherlands; data were collected in multiple ambulatory clinics or during home visits. The primary end point was the ability of the skin barrier to fit body contours; secondary outcomes were leakage of effluent from the pouching system, wear time, and QoL related to using an ostomy product via the validated Ostomy-Q questionnaire. Primary comparisons between concave and comparator pouching systems were evaluated using proportional odds models and mixed models taking test period into account. Analysis included randomized subjects who had been exposed to at least one product and with information on at least one end point (full-analysis-set, n =52). The concave pouching system provided a better fit to body contours than the comparator (P<.001) and reduced the degree of leakage underneath the skin barrier (LS mean difference=-1.84, 95% CI -3.31 to -0.37; P =.016). Participants experienced fewer episodes of leakage outside the skin barrier when using concave versus comparator pouching system (13.0% vs. 26.7%, respectively). Participants reported significant improvements in QoL (LS mean difference=14.3; 95% CI 9.4 to 19.2; P <.001). No significant difference in wear time between skin barrier shapes was reported. Study findings indicate that a pouching system with a concave skin barrier achieved a better body fit on people with an outward peristomal body profile and resulted in fewer leakage incidents and higher QoL compared to using a pouching system with a flat skin barrier.

Discrete spectrum of the magnetic Laplacian on almost flat magnetic barriers

The magnetic Laplacian with a step magnetic field has been intensively studied during the last years. We adapt the construction introduced by Bonnaillie-Noël et al. [Bull. London Math. Soc. 56, 2529 (2024)] to prove the existence of bound states of a new effective operator involving a magnetic step field on a domain with an almost flat magnetic barrier. This result emphasizes the fact that even a small non-smoothness of the discontinuity region can cause the appearance of eigenvalues below the essential spectrum. We also give an example where this effective operator arises.

Generation of human alveolar epithelial type I cells from pluripotent stem cells

Alveolar epithelial type I cells (AT1s) line the gas exchange barrier of the distal lung and have been historically challenging to isolate or maintain in cell culture. Here, we engineer a human invitro AT1 model system via directed differentiation of induced pluripotent stem cells (iPSCs). We use primary adult AT1 global transcriptomes to suggest benchmarks and pathways, such as Hippo-LATS-YAP/TAZ signaling, enriched in these cells. Next, we generate iPSC-derived alveolar epithelial type II cells (AT2s) and find that nuclear YAP signaling is sufficient to promote a broad transcriptomic shift from AT2 to AT1 gene programs. The resulting cells express a molecular, morphologic, and functional phenotype reminiscent of human AT1 cells, including the capacity to form a flat epithelial barrier producing characteristic extracellular matrix molecules and secreted ligands. Our results provide an invitro model of human alveolar epithelial differentiation and a potential source of human AT1s.

Noise Control of Blunt Flat-Plate Using Slit and Dielectric Barrier Discharge Plasma

This paper investigates the combination of a slit at the blunt trailing edge of the flat plate and dielectric barrier discharge plasma to control the vortex shedding of the plate and its associated tonal noise. The noise and flow characteristics of the plate were measured using a far-field microphone array and the particle image velocimetry technique, respectively. The results show that the vortex shedding and the tonal noise can be significantly suppressed by the slit alone, with an average noise reduction of approximately 10 dB in the test Reynolds number. In addition, installing a plasma actuator inside the slit further suppresses the vortex shedding and reduces tonal noise. However, the additional control efficiency of the plasma decreases with increasing wind speeds, with a further 8 dB reduction at a wind speed of U∞=10 m/s (corresponding to an inducing blowing rate BR of 4.5%). However, only an additional 1.5 dB noise reduction is achieved at U∞=20 m/s (BR=2.25%). The particle image velocimetry snapshots were analyzed by proper orthogonal decomposition. The measurements clearly show the variation in vortex shedding at the trailing edge of the plate, revealing the underlying flow mechanisms that lead to the observed noise variations and frequency changes.

Analysis of the inhomogeneous LPG-air flow field in a tube containing mixed obstructions

Based on numerical simulation, this paper further investigates the flow field structure near the obstacle during the premixed gas deflagration. In the deflagration flow field, the pressure gradient variation and vortex structure intensity in the upper surface region of the obstacle are larger, indicating that the pressure gradient has a stronger effect on the vortex structure. The changes in density gradients and pressure gradients induced by the combined rectangular, flat barrier configuration will be more pronounced than in the model with only flat barriers. This change in turn acts back on the combustion field, which in turn has a strong perturbative effect on the flame.

A Novel Polishing Process for Ultra-Smooth Aluminum Surfaces via Anodizing in Sodium Metaborate

A novel ultra-smoothing process for aluminum surfaces was developed using porous alumina formation and subsequent oxide dissolution. A submicron-scale periodic dimpled aluminum surface with an arithmetic mean roughness of 31.5 nm was prepared by anodizing in an etidronic acid solution. This dimpled aluminum specimen was then anodized in a sodium metaborate (NaBO2) solution to form a unique porous alumina film with an extremely flat barrier layer, which differs from the typical hemispherical barrier layer. The outer porous layer became thicker with time during anodizing, whereas the thickness and smoothness of the inner barrier layer were maintained without oxide breakdown. As the porous alumina film was chemically removed in a CrO3/H3PO4 solution, a smooth aluminum surface was exposed. The mean roughness of the aluminum surface drastically decreased to 0.5 nm by short-term anodizing for 15 min and slightly decreased with further anodizing. As a result, an ultra-smooth aluminum surface measuring 0.4 nm in roughness, which is much smaller than that of an electropolished aluminum surface (1.3 nm), was successfully obtained via anodizing in NaBO2 and subsequent oxide dissolution. Our smoothing process was compared with conventional smoothing processes such as electropolishing and barrier oxide formation.

SPECIFICATION ANALYSIS OF STRUCTURAL CREDIT RISK MODEL WITH STOCHASTIC VOLATILITY

In this research, we conduct specification analysis of structural credit risk models with stochastic volatility using term structure of Credit Default Swap (CDS) spreads and equity volatility form high-frequency return data. We also test five representatives of structural credit risk models using samples of 93 single name CDS contracts from January 2010 -2022. The model we consider are; the standard Merton(1974) model, the Black &amp; Cox (1976) model with flat barrier, the Longstaff and Schwartz(1995)model with stochastic interest rates, the Collin- Dufresne and Goldstein (2001) model with stationary leverage, and the double exponential jump diffusion model used in Huang &amp; Huang(2003). Our study provides consistent econometric estimation of the pricing model parameters and specification tests based on the joint behavior of time-series asset dynamics and cross-sectional pricing errors. Our empirical tests reject strongly the standard Merton (1974) model, the Black and Cox (1976) with flat barrier model, the Longstaff, Schwartz (1995) model with stochastic interest rates. The double exponential jump-diffusion barrier model used in (Huang and Huang, 2003) improves significantly over the five models. The best model is the stationary leverage model of Collin-Dufresne and Goldstein (2001), which we cannot reject at 0.5 level of significance in our sample firm. However, our empirical results document the inability of the existing structural models to capture the dynamic behavior of CDS spreads and equity volatility, especially for high investment grade names derivatives. These points to a potential role of time-varying asset volatility, a feature that is missing in the standard structural models.

Simulation of polycrystalline beryllium sputtering by H, D, T atoms

The results of modeling the sputtering coefficients of polycrystalline beryllium by hydrogen isotopes in the range of collision energies of 8 eV-100 keV and their dependences on the angle of incidence of the beam on the surface are presented. This data is necessary for estimating the sputtering of the first wall in the ITER tokamak made from beryllium. A strong surface shape influence on obtained results is shown. The limiting cases of a flat potential barrier (smooth surface) and a spherical potential barrier (a surface consisting of spikes) are considered. The effect of collision cascades on the sputtering coefficient has been established. The dependences of the average depth of sputtered particle formation on the bombarding particles energy are obtained for various angles of beam incidence on the target. The energy spectra and angular dependences of the ejection of sputtered particles are calculated for different energies of bombarding beam atoms. It is shown that the presence of an attractive well in the potential of an incident particle surface changes the sputtering coefficient dependence on incidence angle at small glancing angles. Keywords: Sputtering coefficients, energy and angular distributions of sputtered particles, interatomic potential, hydrogen isotopes, beryllium.

Моделирование распыления поликристаллического бериллия атомами H, D, T

The results of modeling the sputtering coefficients of polycrystalline beryllium by hydrogen isotopes in the range of collision energies of 8 eV–100 keV and their dependences on the angle of incidence of the beam on the surface are presented. This data is necessary for estimating the sputtering of the first wall in the ITER tokamak made from beryllium. A strong surface shape influence on obtained results is shown. The limiting cases of a flat potential barrier (smooth surface) and a spherical potential barrier (a surface consisting of spikes) are considered. The effect of collision cascades on the sputtering coefficient has been established. The dependences of the average depth of sputtered particle formation on the bombarding particles energy are obtained for various angles of beam incidence on the target. The energy spectra and angular dependences of the ejection of sputtered particles are calculated for different energies of bombarding beam atoms. It is shown that the presence of an attractive well in the potential of an incident particle–surface changes the sputtering coefficient dependence on incidence angle at small glancing angles.

Ultrasonic atomization based fabrication of superhydrophobic and corrosion-resistant hydrolyzed MTMS/PVDF coatings

A stable self-cleaning superhydrophobic coating with reliable corrosion resistance was coated on the aluminum alloy 6061. A dense polyvinylidene fluoride (PVDF) layer was first coated by the doctor blade method, and hydrolyzed methyltrimethoxysilane (HMTMS) nanospheres were then deposited on top of the PVDF using ultrasonic spray hydrolysis technique. Superhydrophobic coatings with a contact angle (CA) of 167° and a sliding angle of 7 ​± ​1° were obtained. The superhydrophobic coating exhibited self-cleaning behavior. The corrosion resistance of the layers was investigated in a 3.5 ​wt% NaCl aqueous solution using potentiodynamic polarization measurement and electrochemical impedance spectroscopy techniques, indicating the high corrosion resistance of the flat PVDF barrier and the excellent resistance of the superhydrophobic coating. The charge transfer resistance of the bare aluminum substrate measured as 6.572 ​kΩ ​cm 2 increased to 848.463 ​kΩ ​cm 2 and 3.411 ​× ​10 3 ​kΩ ​cm 2 with PVDF and HMTMS, respectively. The results showed that a proper superhydrophobic coating with good chemical stability could significantly increase the corrosion resistance of the substrate. We also showed the capability of the novel ultrasonic spray hydrolysis technique in fabricating stable superhydrophobic films for large-scale applications.

Nanomorphological changes of anodic aluminum oxide fabricated by anodizing in various phosphate solutions over a wide pH range

High-purity aluminum plates were anodized in phosphoric acid and six phosphate solutions over a wide pH range from acidic to alkaline. The current density corresponding to the growth rate of the anodic oxide was minimum when anodizing in near-neutral solutions and increased when the pH value increased or decreased. A typical porous anodic aluminum oxide (PAAO) film consisting of an outer porous layer and inner hemispherical barrier layer, which is based on the Keller–Hunter–Robinson (KHR) model, was formed in acidic solutions. At the pH values closer to the neutral region, a uniform barrier oxide film or a PAAO film with a narrow porous layer was produced owing to the low solubility of aluminum oxide. On the other hand, two types of characteristic PAAO films were formed during anodizing in alkaline phosphate solutions: one was a PAAO film consisting of an outer porous layer with feathered pore walls and inner hemispherical barrier layer, and the second was a PAAO film consisting of an outer porous layer with elongated pores and inner flat barrier layer. We showed that novel PAAO films, which are not based on the KHR model, can be prepared by anodizing aluminum in various alkaline phosphate solutions.

Transition rate theory, spectral analysis, and reactive paths.

The kinetics of a dynamical system dominated by two metastable states is examined from the perspective of the activated-dynamics reactive flux formalism, Markov state eigenvalue spectral decomposition, and committor-based transition path theory. Analysis shows that the different theoretical formulations are consistent, clarifying the significance of the inherent microscopic lag-times that are implicated, and that the most meaningful one-dimensional reaction coordinate in the region of the transition state is along the gradient of the committor in the multidimensional subspace of collective variables. It is shown that the familiar reactive flux activated dynamics formalism provides an effective route to calculate the transition rate in the case of a narrow sharp barrier but much less so in the case of a broad flat barrier. In this case, the standard reactive flux correlation function decays very slowly to the plateau value that corresponds to the transmission coefficient. Treating the committor function as a reaction coordinate does not alleviate all issues caused by the slow relaxation of the reactive flux correlation function. A more efficient activated dynamics simulation algorithm may be achieved from a modified reactive flux weighted by the committor. Simulation results on simple systems are used to illustrate the various conceptual points.

Methods and Initial Findings of the Observational Study of Ostomy Consumers Registry

BACKGROUND: Longitudinal patient-reported data are limited for people living with an ostomy. PURPOSE: The Observational Study of Ostomy Consumers (OSO) registry collects data from individuals living with an ostomy. METHODS: Self-reported data were collected via repeated electronic surveys completed by adults living with an ostomy in the United States (US) and United Kingdom (UK). RESULTS: Baseline data, collected between October 2018 and February 2021, were available for 299 individuals from the US (77.9%) and UK (22.1%). Most participants reported using a 2-piece pouching system (55.5%) rather than a 1-piece system (44.4%), and using a convex barrier (54.4%) or flat barrier (44.3%). The most commonly reported barrier wear times were ≥ 3 to &lt; 4 days for 36.6% of participants in the US and ≥ 1 to &lt; 2 days for 42.4% of participants in the UK. Despite self-reports of leakage and peristomal skin conditions, quality of life remained positive. A majority of participants (92.0%) reported being very satisfied or somewhat satisfied with their ostomy product. CONCLUSION: The Observational Study of Ostomy Consumers registry allows for a continuous data stream that can be mined to help understand the patient experience over time. Understanding patient experiences will help to inform clinical practice and research, health care utilization, and product innovation.

INFLUENCE OF ACOUSTIC PRESSURE WAVE ON FLAT GYRO SUSPENSION ELEMENTS

The nature of the interaction of sound with an obstacle is revealed. The dynamic characteristics of the plate under an acoustic pressure wave are investigated. A thin isotropic plate was chosen as a mechanical model for the interaction of sound with a flat barrier. The questions of the influence of mechanical impedance for the symmetric and antisymmetric components of sound pressure are considered. Numerical analysis of bending vibrations of the shadow side of the plate is carried out. The value of the lengths of the modulating waves of the main bending vibrations is established

Fabrication of unique porous alumina films with extremely high porosity and an ultra-flat barrier layer by anodizing aluminum in sodium metaborate

Unique porous anodic aluminum oxide (PAAO) films with a completely flat barrier layer and an extremely porous loofah-like structure were fabricated by anodizing aluminum in an alkaline sodium metaborate solution. High-purity aluminum plates were anodized in a 0.3 M sodium metaborate solution at various applied voltages in the range of 0.1–200 V. A typical PAAO film with a spherical cap barrier layer was formed at voltages lower than 50 V, whereas a PAAO film with a flat barrier layer was formed at voltages higher than 100 V; this film formation was not based on the Keller-Hunter-Robinson model with the spherical barrier layer. The growth interface of the flat barrier layer exhibited an ultra-flat morphology with a minimum roughness value of 0.4 nm, which is much smaller than that of an electropolished aluminum surface. Such barrier layer morphology is expected to be formed by field-assisted dissolution without oxide flow. Although the current density slightly decreased with the applied voltage, a relatively higher current density of 6.8 Am−2 was still measured at the lowest voltage of 0.1 V. The alumina walls and the bottom barrier layer gradually thinned as the applied voltage decreased, and a loofah-like PAAO film with an ultra-high porosity of 0.93 was successfully fabricated at 0.1 V. The anodic oxide consisted of amorphous, anion-free aluminum oxide.

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Sea level rise hazardscapes of North Carolina: Perceptions of risk and prospects for policy

Like other risk management strategies, effective sea level rise response must suit local socio-ecological contexts. These include particular civic discourses, perceptions of agency, and analytic deliberation, the latter integrating scientific information with local knowledge and social values. We describe three cases in eastern North Carolina, in the southeastern United States, with differing conceptions of economic development, environmental change, governance, property rights, and social collectivities. On the flat coastal plain and barrier islands, wetland conservation, soft engineering, and other coastal zone management options can protect shorelines from flooding and erosion, whereas hard engineered structures can cause long term problems. Fearing that scientific information would lower real estate values, a well-financed advocacy group averted public discussion of proactive policy by deploying discursive and legislative strategies to suppress scientific decision support. We find that a study site with high financial resources showed the most resistance to science-based adaptation in the public interest, whereas a study site with minimal financial resources was the most receptive. Ideology proves to be a significant consideration in the framing of information to advance coastal policy.

Parametric Studies of a Mercury-Free DBD Lamp

Mercury discharge lamps are often used because of their high efficiency; however, the usage of mercury lamps will be restricted or forbidden for safety and environmental purposes. Finding alternative solutions to suppress mercury is of major interest. The aim of this work is to increase the luminous efficacy of a commercial-free mercury flat dielectric barrier discharge lamp (Planilum, St Gobain) in order to reach the necessary conditions for the lamp to be used as a daily lighting source. The lamp is made of two glass plates separated by a gap of 2 mm. The gap is filled by a neon xenon mixture. The external electrodes made of transparent ITO (indium tin oxide) are deposited on the lamp glass plates. The electrical signal applied to the electrodes generates a UV-emitting plasma inside the gap. Phosphors deposited on the glass allow the production of visible light. The original electrode geometry is plane-to-plane; this induces filamentary discharges. We show that changing the plane-to-plane geometry to a coplanar geometry allows the plasma to spread all over the electrode surface, and we can reach twice the efficacy of the lamp (32 lm/W) as compared to the original value. Using this new electrode geometrical configuration and changing the electrical signal from sinusoidal to a pulsed signal greatly improves the visual uniformity of the emitted light all over the lamp. Electrical and optical parametric measurements were performed to study the lamp characteristics. We show that it is possible to develop a free mercury lamp with an efficacy compatible with lighting purposes.

Kink–antikink scattering-induced breathing bound states and oscillons in a parametrized ϕ4 model

Recent studies have emphasized the important role that a shape deformability of scalar-field models pertaining to the same class with the standard [Formula: see text] field, can play in controlling the production of a specific type of breathing bound states so-called oscillons. In the context of cosmology, the built-in mechanism of oscillons suggests that they can affect the standard picture of scalar ultra-light dark matter. In this paper, kink scatterings are investigated in a parametrized model of bistable system admitting the classical [Formula: see text] field as an asymptotic limit, with focus on the formation of long-lived low-amplitude almost harmonic oscillations of the scalar field around a vacuum. The parametrized model is characterized by a double-well potential with a shape-deformation parameter that changes only the steepness of the potential walls, and hence the flatness of the hump of the potential barrier, leaving unaffected the two degenerate minima and the barrier height. It is found that the variation of the deformability parameter promotes several additional vibrational modes in the kink-phonon scattering potential, leading to suppression of the two-bounce windows in kink–antikink scatterings and the production of oscillons. Numerical results suggest that the anharmonicity of the potential barrier, characterized by a flat barrier hump, is the main determinant factor for the production of oscillons in double-well systems.

(Invited) Anodization of Al in Neutral Oxalate Solution to Form Fine Nanoporous Film

Anodic porous alumina has been widely used as an oxide coating of Al surfaces. Recently, fine and deep nanoporous structures are studied for use as novel templates in various applications. Highly ordered porous alumina is obtained by long-time anodization under appropriate conditions. Typically, hexagonally arranged nanopores with an interpore distance of 100 nm are formed in oxalic acid at 40 V.1 Here, we describe the formation of finer porous alumina (interpore distance of ~25 nm) by anodization in a potassium oxalate solution at 40 V. There have been a few reports on the formation of fine pores in boric acid and borate solutions under hot conditions.2-4 It is thought that the increase in the solubility of the oxide film in the hot borate electrolyte results in the growth of fine pores. However, in the case of anodization in a neutral oxalate solution, a fine nanoporous film was formed in a wide range of temperatures (0-85 °C).Figure 1 (left) shows the results of Al anodization in 0.20 M potassium oxalate (pH 7.6) at 40 V vs Hg/Hg2SO4 for 6 h at 25 °C. The current gradually increased to ~0.4 mAcm-2 in 40 min then gradually decreased. After anodization for 2 h, the current reached a low value and remained at ~0.1 mAcm-2. As shown in the figure, the voltage between the working and counter electrodes remained at 41.7 V. Figure 2 (right) shows a cross-sectional SEM image of the obtained oxide film. Since the interpore distance of anodic porous alumina formed in conventional oxalic acid at 40 V is 100 nm (scale length in Fig. 2), the image clearly indicates that the pores are unusually fine. It is also confirmed that the oxide film is composed of following three layers: an upper porous layer that contains large pores, a lower porous layer with fine and straight pores and a flat barrier layer with a thickness of ~60 nm. The total thickness of the oxide film was 440 nm. It was also confirmed that the growth of nanopores terminates when the anodic current decreases from its peak to a low value.5 References(1) H. Masuda, K Fukuda, Science, 268, 1466 (1995).(2) G. A. Dorsey Jr., J. Electrochem. Soc. 1969, 116, 466.(3) J. S. L. Leach, P. Neufeld, Corros. Sci. 1969, 9, 413.(4) H. Takahashi, M. Nagayama, Electrochim. Acta 1978, 23, 279.(5) K. Nishio, R. Sasaki, Chem. Lett., 2019, 48, 1126. Figure 1