Electrochemical Deoxidation of Titanium and Its Alloy Using Molten Magnesium Chloride

Metallurgical and Materials Transactions B - Oxygen was directly removed from pure titanium and a Ti-6Al-4V alloy by electrolysis in molten MgCl2 at 1173 K (900 °C), where the metal...     

Effect of Peucedanum japonicum Thunb on the expression of obesity-related genes in mice on a high-fat diet

The present study describes the effect of Peucedanum japonicum Thunb (PJT) intake on the expression of obesity-related genes in mice fed a high-fat diet. To explore the mechanism underlying the effect of PJT, This study focused on the expression of genes, especially those related to obesity and metabolism syndrome, in the liver and adipose tissues. In agreement with our previous observations, intake of 10 % PJT for 4 weeks significantly reduced serum triglyceride (TG), leptin, abdominal fat, and adipocyte size. PJT also significantly increased fecal excretion of TG, decreased that of bile acid, and tended to increase the fecal excretion of total cholesterol. Microarray analysis was used to monitor changes in 324 metabolic syndrome-related genes in the liver. Statistically significant upregulation of PPP1R10, RORC, and PBEF1 genes and downregulation of DUSP1, INSIG2, and SERPINA12 genes were noted and confirmed by real-time RT-PCR. These changes were indicative of increased fatty acid oxidation in the maintenance of lipid homeostasis and insulin sensitivity in the livers of PJT-fed mice. PJT increased the expression of PPARγ, FXRα, DGAT1, and ATGL genes, suggesting an enhancement of adipocyte differentiation and normalization of functionality of adipose tissue.     

Influence of various compounds on electrostatic charging tendency in insulating oil

The influence of various compounds on the increase of the electrostatic charging tendency (ECT) in insulating oil was investigated. Sulfide compounds, which are contained in new mineral oil, are identified for the first time as the original materials involved in the increase of the ECT. This is verified by heating tests of alkylbenzene with the addition of various compounds. Coexistence with copper and injection of oxygen enhance the increase of the ECT. Some sulfide and sulfoxide compounds increase the ECT markedly. On the other hand, the influence of sulfones, which are oxidation products of sulfoxides, is negligible. Although sulfonic acids, which are oxidation products of sulfones, markedly increase the ECT, the polarity is reverse. Thus, the ECT is influenced by the kinds and the molecular structures of additive sulfur compounds. The influence of nitrogen compounds and that of oxygen compounds are confirmed to be smaller than that of sulfur compounds. Since the amounts of nitrogen compounds and oxygen compounds are much smaller than those of sulfur compounds in mineral insulating oils, the influence of these compounds is considered negligible. Since the ECT of oils with the addition of sulfides or sulfoxides increases after heating, the other compounds should be created from these compounds that increase the ECT directly. Thus, the increase of the ECT is mostly caused by the oxidation of sulfides, which creates sulfoxides. Then certain compounds, which directly increase the ECT, are created from sulfoxides. If sulfones or sulfonic acids are created by the oxidation of sulfoxides, the ECT decreases because of the influence of these compounds on the ECT. It is most likely that some process other than oxidation occurs in the creation of the compounds that increase the ECT directly. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 176(3): 29–36, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21112     

Enhanced bioactivity of polyvinylidene chloride films using argon ion bombardment for guided bone regeneration

Polyvinylidene chloride (PVDC) is a long chain carbon synthetic polymer. The objective of this study was to improve the bioactivity of PVDC films through surface modification using argon (Ar) ion bombardment to create Ar-modified PVDC films (Ar-PVDC) to address the clinical problems of guided bone regeneration (GBR), which is technique-sensitive, and low bone regenerative ability. First, the effects of Ar ion bombardment, a low temperature plasma etching technique widely used in industry, on PVDC film wettability, surface chemistry, and morphology were confirmed. Next, fibroblast-like and osteoblast-like cell attachment and proliferation on Ar-PVDC were assessed. As a preclinical in vivo study, Ar-PVDC was used to cover a critical-sized bone defect on rat calvaria and osteoconductivity was evaluated by micro-computed tomography analysis and histological examinations. We found that the contact angle of PVDC film decreased by 50° because of the production of –OH groups on the PVDC film surface, though surface morphological was unchanged at 30 min after Ar ion bombardment. We demonstrated that cell attachment increased by about 40 % and proliferation by more than 140 % because of increased wettability, and 2.4 times greater bone regeneration was observed at week 3 with Ar-PVDC compared with untreated PVDC films. These results suggest that Ar ion bombardment modification of PVDC surfaces improves osteoconductivity, indicating its potential to increase bone deposition during GBR.     

Friction properties of new porous carbon materials: Woodceramics

Woodceramics are new porous carbon materials obtained from wood or woody materials impregnated with phenol resin, and carbonized in a vacuum furnace at high temperature. Woodceramics have several superior characteristics from the viewpoints of engineering materials and ecological materials: they are hard and strong, have porous structure and low density, are made from natural resources, do not cause environmental pollution, and are cheap to manufacture. This paper describes the fundamental friction properties of Woodceramics in sliding contact with several materials. Woodceramics made of medium density fiberboard (MDF) and beech impregnated with phenol resin and carbonized in a vacuum furnace at 800°C and 2000°C were rubbed against alumina, silicon nitride, bearing steel and diamond by using a reciprocating friction apparatus. Experiments were carried out unlubricated in air, impregnated with base oil and in water, at several normal loads and sliding velocities. The following principal results were obtained: (1) The friction coefficient is around 0.15, under all three lubrication conditions; (2) The friction coefficient slightly decreases and then stays constant with increasing normal load; (3) The friction coefficient is not affected by sliding velocity; (4) Woodceramics have a good self-lubricity.     

Electrochemical deoxidation of titanium

Removal of oxygen in titanium using an electrochemical technique was examined at temperatures around 1223 K with the purpose of obtaining nearly oxygen-free titanium. Titanium and carbon electrodes, immersed in molten CaCl₂, served as cathode and anode, respectively, with an external DC source. CaCl₂ was employed to produce the deoxidant calcium and to facilitate the reaction by decreasing the activity of the by-product CaO. By applying about 3 V between the electrodes, the calcium potential in CaCl₂ was increased at the titanium cathode surface and titanium samples of the cathode could be deoxidized by the electrolytically produced deoxidant calcium or by calcium of high activity in the CaCl₂ flux. Resulting O²⁻ species, mainly present as the deoxidation product CaO in the flux, reacted at the carbon anode to form CO (or CO₂) gas which was removed from the system. Titanium wires containing 1400 mass ppm oxygen were deoxidized to less than 100 mass ppm, whereas the carbon concentration increased by about 50 mass ppm. In some cases, the oxygen concentration in titanium samples was lowered to a level less than 10 mass ppm that could be determined by conventional inert gas fusion analysis. The behavior of contaminants, such as carbon and nitrogen, is also discussed.     

Identification of metallothionein isoforms with capillary zone electrophoresis using a polyacrylamide-coated tube

Botulinum C2 toxin is composed of two nonlinked protein components, component-I (light chain) and component-II (heavy chain). It is produced by Clostridium botulinum types C and D, and is thought to play a lethal pathogenic role. These biological activities of C2 toxin may be due to the ADP-ribosylation of non-muscle actin by component-I of the toxin. We were able to isolate two overlapping gene fragments encoding component-I from the chromosomal DNA of Clostridium botulinum type C strain (C)-203U28, and determine the complete nucleotide sequence of component-I gene. The gene for component-I, bc21, consists of one open reading frame (ORF) encoding 431 amino acid residues (1293 nucleotides) without signaling peptide sequence. The molecular mass calculated from the deduced amino acid sequence was 49400.37 Da. Mono-ADP-ribosyltransferase activity was demonstrated in the lysate from E. coli transformed by the recombinant plasmid, pGEM-C2 encompassing whole component-I gene with its own promoter.     

Application of random amplified polymorphic DNA analysis for detection of Salmonella spp. in foods

The random amplified polymorphic DNA (RAPD) band patterns from 23 Salmonella spp. produced by use of an oligonucleotide primer (called du primer) designed on the basis of the N-terminal sequence of dulcitol 1-phosphate dehydrogenase (5'-GTGGTGACCCAGGATGGCCAGGTG-3') were different from those from 16 non-Salmonella spp. The bands at 460 and 700 bp were produced in all Salmonella strains tested. These RAPD fragments obtained from Salmonella typhimurium strongly hybridized with the corresponding RAPD bands from the other strains of Salmonella, but not with those from non-Salmonella spp. in Southern blot analysis. The RAPD bands were detected by ethidium bromide staining even when genomic DNA prepared from as few as 2.8 x 10(3) cells was used. The minimum detectable cell number in the initial inoculum of S. typhimurium was 4 x 10(-1) CFU/25 g of raw beef after the preenrichment in Enterobacteriaceae enrichment mannitol (EEM) broth for 6 h and the selective enrichment in dulcitol-magnesium chloride-pyridinesulfonic acid-brilliant green-novobiocin (DMPBN) medium for 18 h at 42 degrees C. Seven raw foods inoculated with S. typhimurium at numbers from 4 x 10(-1) to 2.6 x 10(2) CFU/25 g of food were positive in both the RAPD analysis and the conventional culture method.