Polishing of single point diamond tool based on thermo-chemical reaction with copper

This paper describes a new polishing method for diamond cutting tools. The method is based on the principle of oxidization of copper and deoxidization of copper oxide by carbon. A diamond tool was brought into contact with a copper plate, heated in air to a range of 323–523 K. The depth of the removed layer of diamond increased almost linearly with contact time and reached approximately 7 nm after 6 h. In this erosion process, pre-existing microcracks on the diamond surface were reduced. In comparison with the mechanically polished tool, the thermo-chemically polished tool was highly resistant to chipping and yielded a significant rise in tool life.     

Low-temperature synthesis of barium titanate thin films by nanoparticles electrophoretic deposition

The nanoparticles electrophoretic deposition (EPD) of barium titanate (BaTiO₃ or BTO) thin films was investigated. BTO nanocrystallites in a pseudocubic perovskite phase with an average particle size of about 10 nm were synthesized at a low temperature of 90°C by a high-concentration sol–gel process. By using a mixed solvent of 2-methoxyethanol and acetylacetone as dispersing medium, transparent and well-dispersed BTO nanocrystallites suspensions within the concentration range of 0.0125 to 0.20 mol/l was successfully prepared for nanoparticles EPD. A uniform microstructure and a smooth surface were observed on the deposited films. The film thickness of the deposited films increased rapidly with increasing EPD time in the initial period of EPD, and thereafter gradually increased to a limited thickness. With increasing applied EPD voltage, the limited film thickness increased. A near linear relation between the film thickness of films and the concentration of suspensions was observed under the same EPD conditions. The microstructures of the deposited BTO thin films were investigated.     

Effects of carbon dioxide (CO2) laser perforation as skin pretreatment to improve sugar infusion process of frozen blueberries

Sugar infusion is a widely used osmotic treatment for fruit preservation, but the process is inherently slow and the waxy skins of some fruits hinder mass transfer during the process. This work examined the utility of perforation by a carbon dioxide (CO(2)) laser as a novel skin treatment to improve the infusion process. In 2 experiments, individually quick frozen (IQF) blueberries were subjected to varying degrees of laser perforation (3 levels of perforation density × 3 levels of perforation depth), and then infused stepwise with high fructose corn syrup (HFCS) to a final °Brix of 70 using varying solution concentration increment (5, 10, 20, and 30 °Brix/d). At each concentration, increasing perforation density and depth promoted solute migration into the fruit with increased fruit weight (P < 0.05; up to 24.15%, 37.23%, 52.89%, 65.34% wt. increase at 5, 10, 20, and 30 °Brix/d compared to the controls). Laser-treated blueberries maintained the original shape without excessive shrinkage and texture hardening due to enhanced solute incorporation, while the controls and mechanically treated samples were ruptured and wrinkled at the end of the process. Increasing solution concentrations shortened the process duration but decreased final fruit weight due to greater osmotic gradients. However, negative effects of using higher solution concentrations on final fruit weight were significantly alleviated with moderate-to-high doses of laser perforation (P < 0.001). Overall, the results demonstrate that laser perforation can be a viable skin pretreatment technique, offering marked improvement on final process yield, process efficiency, and product quality. PRACTICAL APPLICATION: CO(2) laser perforation as a novel skin pretreatment for sugar infusion of individually quick frozen (IQF) blueberries is presented. The technique markedly improves the product yield and quality. Although further investigation is needed, the method may potentially be used for other waxy skin fruits such as cranberries and cherries.     

Vitamin B6 suppresses serine protease inhibitor 3 expression in the colon of rats and in TNF-α-stimulated HT-29 cells

Scope: Previous reports in the areas of animal studies and, recently epidemiology, have linked anti‐tumorigenic and anti‐inflammatory effects to dietary vitamin B6. This study investigated the molecular mechanism of these effects of vitamin B6. Methods and results: DNA microarray analysis was used to obtain information on changes in colon gene expression from vitamin B6 (pyridoxine) repletion in vitamin B6‐deficient rats. Pyridoxine supplementation down‐regulated the inflammatory molecule, serine protease inhibitor clade A member 3 (SPI‐3) mRNA expression in the colon. This study also showed that tumor necrosis factor α (TNF‐α) induced SPI‐3 mRNA expression in HT‐29 human colon cancer cells, and vitamin B6 (pyridoxal hydrochloride) pretreatment of HT‐29 cells inhibited TNF ‐induced mRNA expression of SPI‐3. Vitamin B6 inhibited TNF‐α‐induced NF‐κB activation via suppression of IκBα degradation in HT‐29 cells. HT‐29 cells stably expressing epitope‐tagged ubiquitin were generated and vitamin B6 pretreatment was shown to inhibit ubiquitination of the IkB protein in response to TNF‐α‐i. Conclusion: Vitamin B6 suppressed SPI‐3 expression in the colon of rats and in TNF‐α‐stimulated HT‐29 cells. Further, this study showed a possible role of vitamin B6 in the regulation of protein ubiquitination.     

Cigarette smoke extract enhances oxytocin-induced rhythmic contractions of rat and human preterm myometrium

Although smoking during pregnancy is a major risk factor for preterm delivery, the underlying mechanism by which smoking stimulates uterine contractions is still poorly understood. In the present study, we tried to clarify the effects of smoking on myometrial contractility induced by oxytocin (OT) using cigarette smoke extract (CSE). Myometrial strips, which were taken from the rat on day 16 of pregnancy, and from human preterm and term delivery groups, were incubated overnight with several doses of CSE at 37 degrees C under non-hormonal conditions. The uterine contractile sensitivity and activity (force and frequency) upon exposure to OT were investigated. Furthermore, the expression levels of oxytocin receptor (OTR) mRNA in the myometrial strips were investigated by real-time PCR. Contractile sensitivity to OT in the rat CSE (10(-7) pieces/ml) group was found to be significantly higher than in the control group (P < 0.05). Contractile activity did not differ between the CSE and control groups. The expression levels of rat OTR mRNA in the CSE (10(-7) pieces/ml) group were significantly higher than in the control group (P < 0.01). Similarly, in preterm myometrial strips, the expression levels of human OTR mRNA in the CSE (10(-7) pieces/ml) group were significantly higher than in the control group (P < 0.05). These findings suggest that CSE directly increases the contractile sensitivity of preterm myometrium in response to OT by upregulating the expression of OTR mRNA and thereby increases the risk of preterm delivery in women, who smoke during pregnancy.     

Suppression of mutagens-induced SOS response by phytoncide solution using Salmonella typhimurium TA1535/pSK1002 umu test

Four types of phytoncide solution (A-Type, AB-Type, D-Type and G-Type) were evaluated as antimutagenic agents with suppressive effects on the SOS-inducing activity of the mutagen 2-(2-furyl)-3-(5-nitro-2-furyl) acrylamide (furylfuramide) using Salmonella typhimurium TA1535/pSK1002 umu test. The A-Type, AB-Type, D-Type and G-Type of phytoncide solution suppressed the SOS-inducing activity on furylfuramide at a concentration of 100 microg/mL by 86.1%, 74.7%, 69.5% and 55.4%, respectively, and the ID(50) (50% inhibitory dose) values were 9.0 microg/mL, 22.5 microg/mL, 36.0 microg/mL and 72.8 microg/mL. They also showed the suppression of SOS-inducing activity against other chemical mutagens, such as 4-nitroquinolin 1-oxide (4NQO) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), which do not require liver metabolizing enzymes, and against 2-aminoanthracene (2AA) and 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), which require these enzymes, and against UV irradiation, which is a well known physical mutagen. In the search for the component-activity relationship, the A-Type of phutoncide solution suppressed the SOS-inducing activity greater than the other types of phutoncide solution for furylfuramide, 4NQO and MNNG. However, in case of 2AA and Trp-P-1, the D-Type of phytoncide solution was most effective in suppressing the SOS-inducing activity in the umu test. From these results, the four types of phytoncide solutions showed the suppressive effect of SOS-inducing activity against chemical and physical mutagens.     

Effect of ratcheting deformation on fatigue and creep-fatigue life of 316FR stainless steel

Components of fast breeder reactor (FBR) plants will be subjected to large thermal load, and progressive deformation with loading cycles (ratcheting) and creep-fatigue damage should be considered in their design. To clarify the effect of ratcheting on fatigue and creep-fatigue life, a series of fatigue and creep-fatigue tests coupled with strain progress were carried out for 316FR stainless steel. It was found that tensile ratcheting decreases the failure life to a large extent at small strain range, while compressive ratcheting does not decrease the failure life. Measurement of striation intervals on fracture surface showed small influence of strain increment on the crack propagation rate, suggesting that the main cause of the life reduction is the decrease in the crack initiation life. It was also found that failure life in various conditions is correlated well with a product of strain range and tensile peak stress.     

A Novel Thermosensitive Poly(methyl 2-acetamidoacrylate)

The thermosensitive properties of aqueous poly(methyl 2-acetamidoacrylate) (PMAA) solutions were investigated in the absence or presence of sodium sulfate. Poly(methyl 2-acetamidoacrylate) with a molecular weight of 23,000 (PMAA-1) exhibited the cloud point. On heating the PMAA-1 solution, the transmittance began to decrease from near 34°C and increased again after the minimum value was shown at 36.0°C. The minimum transmittance increased linearly with an increasing concentration of the polymer although the minimum-transmittance temperature did not depend on polymer concentration. The minimum transmittance was affected by the pH and the 1-butanol added. This finding suggests that the cloudiness is controlled by a delicate balance of hydrophilicity and hydrophobicity and by intra- and/or inter-molecular hydrogen bonding. Poly(methyl 2-acetamidoacrylate) with a molecular weight of 15,000 (PMAA-2) did not exhibit cloudiness in distilled water. However, the addition of sodium sulfate caused cloudiness to appear. The cloud point of a PMAA-2 solution depended on concentrations of polymer and salt added. It decreased with an increase in polymer and salt concentrations. The salting-out constants were determined from the relationship between the cloud point and concentrations of polymer and salt.     

Development and Continuous Operation of a Bench-Scale System for the Production of O3 + O2 + CO2 Hydrates

Ozone (O₃) has many industrial applications such as in sterilization. One of the long-term O₃ preservation methods is molecular storage in clathrate hydrate. In this study, an experimental system was developed for continuously forming O₃ + O₂ + CO₂ hydrates. The parameters that affect the continuous operation of the system and that lead to increases in the concentration of O₃ in the hydrates were also experimentally evaluated, implementing the method of quality engineering. After optimizing these operating parameters, the O₃ storage capacity in the hydrates was measured to be 0.26 wt % at 2 h of total operation time. By X-ray diffraction, it was found that the produced sample contained hydrates, and long-term preservation for 6 months was possible at the temperature of general freezing warehouses.