Search

Background: Dry skin can trigger eczema that affects >10% of the US population. Dressing films have been developed to improve diseased skin, but there is limited knowledge about their effects, especially for dry skin‐related symptoms. We developed an electrospinning method that creates a coating film, called a fine fiber (FF) film, characterized by the production of a transparent, thin, flexible, and adherent membrane on the skin surface. Objective: The aim of this pilot study was to examine the effects of the FF film on dry skin. Methods: Three treatments (lotion only, lotion with the FF film, and lotion with an alternative film) were designed to treat subjects with rough skin on their lower legs. Twenty‐four females were enrolled and used either a water‐based lotion U or a petrolatum‐based lotion P and the FF film for 2 weeks followed by a regression phase for 1 week. Skin hydration and roughness scores were assessed as were the subjects' perceptions of the effects. Results: When the FF film was applied with lotion U, skin hydration was significantly improved even after 1 week, accompanied by a significant improvement of skin roughness and an increase in skin hydration by the end of the regression phase. An evaluation of moisture permeability suggested that the FF film, especially with lotion U, performed as a semipermeable membrane with optimal moisture healing effects on dry skin. Conclusion: The FF film together with a water‐based lotion is a promising treatment to quickly improve dry skin conditions. [ABSTRACT FROM AUTHOR]

Background: The lipid components and natural moisturizing factors (NMFs) of the stratum corneum (SC) are integral pieces of the self-regulating barrier strategy which comprises one of the most important functions of human skin and seems to be related to biomechanical responses of the SC. Objectives: This work presents the contributions of the lipid bilayers and NMFs to the barrier properties and mechanical responses of human SC. Methods: We performed 2 biomechanical experiments, substrate curvature testing and double cantilever beam cohesion measurements, on isolated human SC exposed to either water, a 1:1 mixture of acetone/ether, or a 1:1 mixture of chloroform/methanol for various durations. Results: We show that treating ex vivo SC with organic solvents results in lipid extraction which increases with duration of exposure. This extraction is tied to a remarkably linear increase in the levels and rates of biaxial stress development during drying/hydration cycles. This effect appears to be tied to the total amounts of lipids extracted. Furthermore, striking changes are seen in the intercellular cohesion properties of the tissue after solvent exposure. Interestingly, changes in drying stress profiles are not observed after treatment with water, which has been previously shown to remove NMFs from the tissue, and which therefore might be expected to induce changes in the drying behavior of the skin. However, changes in intercellular cohesion and the SC cohesion gradient are seen, suggesting impacts on the corneodesmosome protein binding junctions within the tissue. Conclusions: These results suggest that lipid loss causes marked increases in SC drying stresses, which may in turn contribute to changes in skin perception. NMF extraction may be important in vivo, but has remarkably little impact in isolated SC. [ABSTRACT FROM AUTHOR]

The correction of an inactivated hygromycin resistance and enhanced green fluorescent protein (Hyg–EGFP) fusion gene by a several hundred-base single-stranded (ss) DNA fragment has been reported. In this study, the effectiveness of this type of gene correction was examined for various positions in the rpsL gene. Sense and anti-sense ssDNA fragments were prepared, and the gene correction efficiencies were determined by co-introduction of the target plasmid containing the gene with the ssDNA fragments. The gene correction efficiency varied (0.8–9.3%), depending on target positions and sense/anti-sense strands. Sense ssDNA fragments corrected the target gene with equal or higher efficiencies as compared to their anti-sense counterparts. The target positions corrected with high efficiency by the sense fragments also tended to be corrected efficiently by the anti-sense fragments. These results suggest that the sense ssDNA fragments are useful for the correction of mutated genes. The variation in the correction efficiency may depend on the sequence of the target position in double-stranded DNA. [ABSTRACT FROM PUBLISHER]

Introduction of nitrogen gas induces inefficient Al beam termination when the shutter closes during molecular beam epitaxy. In spite of the closed shutter of the Al cell, the epitaxial layer contains Al at a concentration (nAl) of over 1018 cm-3. This depends on the vapor pressures of N2 (PN2 ) and Al (PAl) as nAl ∝PN2 PAl. An analytical model considering gas phase scattering reproduce the dependences, suggesting that a large amount of N2 gas causes the scattering of residual Al atoms with an occasional collision resulting in the atoms directed toward the substrate. Possible impacts on the epitaxial layer, caused by the Al incorporation and related phenomena, are also discussed. The scattering of Al, and its getter effect on other elements especially O can cause further undesirable incorporation of impurities within the epitaxial layer. [ABSTRACT FROM AUTHOR]

We undertake an exclusive study on the plasma-assisted molecular-beam epitaxy of GaNAs, focusing on plasma conditions. We investigate the effects of species contributing to growth and the ions produced on the resulting structural and optical characteristics of the epitaxial layer, and the effect of rapid thermal annealing on the layer. The larger the RF power, the larger the amount of both atomic N and metastable molecule N2* are produced, resulting in a monotonic increase in nitrogen incorporation. An increase in the nitrogen gas flow rate leads to the saturation of nitrogen incorporation, followed by a reduction in atomic N. Both atomic N and metastable molecule N2* contribute to the growth. The number of ions produced is larger at a larger RF power and lower nitrogen gas flow rate, but is almost negligible near the border of the plasma mode transition. The sample exposed to fewer ions during growth shows better optical properties. [ABSTRACT FROM AUTHOR]

Dilute nitrides are novel III–V semiconductors that have been developed for photonic and electronic devices. Although they have been investigated, some of their characteristics have not been established yet. In this study, the static dielectric constant of dilute nitrides was experimentally estimated from the exciton binding energy. The results imply that nitrogen incorporation in III–V semiconductors decreases both the static dielectric constant and bandgap. This behavior is opposite to that of conventional semiconductors. [ABSTRACT FROM AUTHOR]

We report the unintentional incorporation of Al during the growth of molecular beam epitaxy using RF plasma source, driven by N2 gas flow. The concentrations of N, Al, O, and C within GaNAs/GaAs/AlAs structure are investigated by secondary ion mass spectrometry. In spite of the closed shutter of Al cell, we observe Al incorporation with a concentration up to 1×1018 cm-3 in GaNAs layer and characteristically in the bottom side GaAs. Its concentration is solely dependent on N2 gas flow rate. Remarkably, the operation of the RF plasma has no impact on that. C and O show their concentrations corresponding to the extrinsic Al. The complex interactions between those elements predict a possible origin of material deteriorations and difficulty for the precise doping control. [ABSTRACT FROM AUTHOR]