Prospective method of lightning protection schemes in distribution system

Grounding wires and enclosed ZnO elements have been incorporated generally in 6.6‐kV distribution systems by TEPCO for the reduction of lightning overvoltages. At present, the reliability to lightning surges is tolerably good. However, the facility of grounding wires is not inexpensive and its maintenance is hard due to corrosion and disconnection in some areas. A typical model simulating TEPCO field adopting enclosed ZnO elements has been developed and we have evaluated relative failure risks systematically according to conditions with and without grounding wires against lightning overvoltages. Two kinds of failures discussed in the paper are the flashover of insulation and the overduty of ZnO elements, and two kinds of induced and direct lightning overvoltages are studied in flashover. The greatest problem with no grounding wire is the increase of ZnO elements' duty, but it was demonstrated that a short partial grounding wire around ZnO elements or the selection of heavier ZnO elements provides a solution. The main objectives of this study are to clarify the relative failure risks systematically according to realistic field conditions, the risk of small stroke currents having long duration to ZnO elements' duty, and countermeasures against ZnO elements' overduty. © 1999 Scripta Technica, Electr Eng Jpn, 127(1): 1–10, 1999     

Oat-based complex stimulates skin barrier protein synthesis and reduces skin ageing

Citation: IFSCC Magazine , 11 (2008) (3) 225–229
The dermis is considered a highly dynamic structure that determines the biomechanical properties of the skin. It is composed of two dermal compartments separated by a vascular plexus: the papillary dermis and the reticular dermis. In the last few years, several studies have demonstrated the role of the dermal epidermal junction in the cutaneous ageing process. Recently, teams specialized in the study of the dermal matrix have focused their studies on the superior dermis in close contact with the dermal epidermal junction: the papillary dermis. They defined the role of matrix proteins in this area. Collagens XII and XVI, non-fibrillar collagens specific to the papillary dermis, are responsible for skin deformability and extensibility. Oxytalan fibres are related to elastic properties of the skin. Ubiquitous collagens such as collagens I and VI are associated with the cohesion and the resistance of the dermis. As the papillary dermis is the primary site of intrinsic dermal ageing, we studied expression of these molecules in our own in vitro model of intrinsic ageing of the papillary dermis. The results of this innovative approach confirmed that their expression was reduced. Nevertheless, active molecules may exist in nature that are capable of restoring a normal expression profile of these markers for a cosmetic anti-ageing application.
Keywords:  Anti-ageing, papillary dermis, collagens XVI and XII, oxytalan fibres     

High-sensitivity detection of proteins using gel electrophoresis and atomic force microscopy

We have developed a method to detect specific proteins with a high sensitivity using a gel electrophoresis method and force measurement of atomic force microscopy (AFM). Biotinylated proteins were separated by electrophoresis and fixed with cross-linking chemicals on the gel, followed by direct force measurement between the biotinylated proteins on the gel and a streptavidin-modified tip of an AFM cantilever. We were able to achieve a high enough sensitivity to detect the picogram order of the biotinylated proteins by evaluating the frequency of the interaction force larger than 100 pN in the force profile, which corresponds to the rupture force of interaction between streptavidin and biotin.     

Monitoring the cell number of Lactococcus lactis subsp. cremoris FC in human feces by real-time PCR with strain-specific primers designed using the RAPD technique

Strain-specific PCR primers for Lactococcus lactis subsp. cremoris FC were developed using the randomly amplified polymorphic DNA (RAPD) technique. RAPD was used to generate strain-specific markers. A 1164-bp RAPD marker found to be strain-specific was sequenced, and a primer pair specific for L. lactis subsp. cremoris FC was designed. The specificity of this primer pair was tested with 23 L. lactis subsp. cremoris strains and 20 intestinal bacterial species, and was found to be strain-specific. Subsequently, this primer pair was subjected to the quantification of L. lactis subsp. cremoris FC in the feces of subjects fed fermented milk containing this strain. After administration, L. lactis subsp. cremoris FC was detected in the feces of all 7 subjects, with the maximum number being between 10(5) and 10(9) cells g(-1) of feces. Furthermore, this strain was detected in only one feces sample 2 weeks after administration was stopped. These results suggest that L. lactis subsp. cremoris FC can survive passage through the gastrointestinal tract.     

Interaction control between endohedral metallofullerene and metal substrate by introducing alkanethiol self-assembled monolayer

The interaction control between endohedral metallofullerenes and a metal substrate has been demonstrated by introducing hexanethiol, octanethiol, and decanethiol self-assembled monolayers (SAMs) as the interlayer. We observe the electric properties of terbium endohedral metallofullerenes (Tb@C82) on alkanethiol SAMs with different chain lengths by scanning tunneling microscopy (STM) and spectroscopy (STS). Based on the comparison of the high-resolution STM images of a Tb@C82 molecule on hexanethiol and octanethiol SAMs, the interaction between Tb@C82 and a hexanethiol SAM is found to be larger than that between Tb@C82 and an octanethiol SAM; this is because at 68 K, the rotational states of Tb@C82 terminate only on the hexanethiol SAM. Furthermore, we find that the tunneling current-voltage characteristics of Tb@C82 on the hexanethiol SAM show the rectifying effects that are also caused by the molecular energy level shifts of Tb@C82 molecules due to the large interaction.     

Evaluation of local deformation behavior accompanying fatigue damage in F82H welded joint specimens by using digital image correlation

By using digital image correlation, the deformation behaviors of local domains of F82H joint specimens welded using tungsten inert gas (TIG) and electron beam (EB) welding were evaluated during tensile and fatigue testing. In the tensile test specimens, the tensile strength decreased in the TIG-welded joints, and ductility decreased in both the EB- and TIG-welded joints. Because axial strain increased in the tempered heat-affected zone (HAZ) and led to the fracture of the TIG-welded joint, the strength was considered to have decreased because of welding. In fatigue testing, the number of cycles to fracture for the welded joint decreased to less than 40–60% of that for the base metal. For both fracture specimens, the largest value of shear strain was observed in the region approximately between the fine-grained HAZ and tempered HAZ; this shear strain ultimately led to fracture. Cavities and macrocracks were observed in the fine-grained HAZ and tempered HAZ in the cross sections of the fracture specimens, and geometrical damage possibly resulted in the reduction of fatigue lifetime.     

Direct dissimilar joining of aluminium alloys and polyamide 6 by friction lap joining*

Direct dissimilar joining of various Al alloy (A1050, A3004, A5052 and A5083) plates and a polyamide 6 plate was performed using friction lap joining (FLJ) with the Al alloy plate as a top and the polyamide 6 plate as a bottom. The effect of Mg content in Al alloys on the joining strength was investigated. TEM analysis made clear that the polyamide 6 and Al alloys were joined via oxide layer consisting of Al₂O₃ and MgO. The results of XPS analysis indicated that MgO was formed by the heating during FLJ, and the quantity of MgO was increased with increasing Mg content in Al alloys. The tensile shear strengths of A3004, A5052 and A5083 joints were saturated to about 2 kN because of the tensile fracture at the polyamide 6 plate outside the tool-passed zone, which were higher than that of the A1050 joint fractured at the joint interface. The peel strength of the joint was increased with increasing Mg content in Al alloys, and the fracture occurred both at the joint interface and at the polyamide 6 plate on the joint area. The fraction of polyamide 6 plate fracture was also increased with increasing Mg content in Al alloys.     

Beta tricalcium phosphate ceramics with controlled crystal orientation fabricated by application of external magnetic field during the slip casting process

Beta tricalcium phosphate (β-TCP) is a resorbable bioceramic that has hitherto been utilized in the medical field. Since it crystallizes in the anisotropic hexagonal system, properties such as chemical and physical ones are expected to depend on its crystal axis direction and/or on its crystal plane (anisotropy). Control of crystal orientation is thus important when used in polycrystalline form. Meanwhile, application of a strong magnetic field has been found to be a promising technique to control crystal orientation of anisotropic shape or structured crystals. In this work, we attempted to fabricate β-TCP ceramics with controlled crystal orientation by applying an external magnetic field during the slip casting process and subsequently sintering them at 1050 °C, below the β–α transition temperature. Application of a vertical magnetic field increased intensities of planes perpendicular to c-plane on the top surface, while a horizontal one with simultaneous mechanical mold rotation decreased it. These results indicated that crystal orientation of β-TCP ceramics were successfully controlled by the external magnetic field and together that the magnetic susceptibility of β-TCP is χ_c⊥ > χ_c//.     

Skin Permeation of Lidocaine from Crystal Suspended Oily Formulations

ABSTRACT

In vitro permeation of lidocaine (lidocaine base, LID) through excised rat skin was investigated using several LID-suspended oily formulations. The first skin permeation of LID from an LID-suspended oily solution such as liquid paraffin (LP), isopropyl myristate (IPM), polyoxyethylene (2) oleylether (BO-2), and diethyl sebacate (DES) was evaluated and compared with that from polyethylene glycol 400 (PEG400) solution, a hydrophilic base. The obtained permeation rate of LID, J_app, from PEG400, LP, IPM, BO-2, and DES was in the order of DES>BO-2 = IPM>LP>PEG400, and increased with LID solubility in the oily solvents, although LID crystals were dispersed in all solvents. Subsequently, oily formulations that consisted of different ratios of the first oily solvent (IPM, BO-2, or DES) (each 0–20%), the second oily solvent (LP) and an oily mixture of microcrystalline wax/white petrolatum/paraffin (1/5/4) were evaluated. BO-2 groups at a concentration of 5% and 10% had the highest J_app among the oily formulations, although a higher BO-2 resulted in lower skin permeation. In addition, pretreatment with BO-2 increased the skin permeation of LID. These results suggest that the penetration enhancing effect by the system may be related to the skin penetration of BO-2 itself. Finally, mathematical analysis was done to evaluate the effect of BO-2, and it was shown that BO-2 improved the LID solubility in stratum corneum lipids to efficiently enhance the LID permeation through skin.