Fabrication and nano-imprintabilities of Zr-, Pd- and Cu-based glassy alloy thin films

With the aim of investigating nano-imprintability of glassy alloys in a film form, Zr(49)Al(11)Ni(8)Cu(32), Pd(39)Cu(29)Ni(13)P(19) and Cu(38)Zr(47)Al(9)Ag(6) glassy alloy thin films were fabricated on Si substrate by a magnetron sputtering method. These films exhibit a very smooth surface, a distinct glass transition phenomenon and a large supercooled liquid region of about 80 K, which are suitable for imprinting materials. Moreover, thermal nano-imprintability of these obtained films is demonstrated by using a dot array mold with a dot diameter of 90 nm. Surface observations revealed that periodic nano-hole arrays with a hole diameter of 90 nm were successfully imprinted on the surface of these films. Among them, Pd-based glassy alloy thin film indicated more precise pattern imprintability, namely, flatter residual surface plane and sharper hole edge. It is said that these glassy alloy thin films, especially Pd-based glassy alloy thin film, are one of the promising materials for fabricating micro-machines and nano-devices by thermal imprinting.     

Bacterial communities in petroleum oil in stockpiles

Bacterial communities in crude-oil samples from Japanese oil stockpiles were investigated by 16S rRNA gene cloning, followed by denaturing gradient gel electrophoresis (DGGE) analysis. 16S rRNA genes were successfully amplified by PCR after isooctane treatment from three kinds of crude-oil sample collected at four oil stockpiles in Japan. DGGE profiles showed that bacteria related to Ochrobactrum anthropi, Burkholderia cepacia, Stenotrophomonas maltophilia, Propionibacterium acnes, and Brevundimonas diminuta were frequently detected in most crude-oil samples. The bacterial communities differed in the sampling time and layer. Among the predominant bacteria detected in the crude oil, only three species were found for bacteria isolated on agar plates and were related to Burkholderia, Stenotrophomonas, and Propionibacterium, while Ochrobactrum sp. could not be isolated although this species seemed to be the most abundant bacterium in crude oil from the DGGE profiles. Using an archaea-specific primer set, methanogens were found in crude-oil sludge but not in crude-oil samples, indicating that methanogens might be involved in sludge formation in oil stockpiles.     

Deformation–wear transition map of DLC coating under cyclic impact loading

A new deformation–wear transition map of hydrogen-free amorphous carbon coating (commonly known as Diamond-Like Carbon (DLC) coating) on tungsten high speed steel (SKH2) substrate under cyclic impact loading has been proposed to clarify the interactions of the operating parameters, deformation and wear. The study was carried out using an impact tester, under lubricated conditions over a wide range of impact cycles, and applied normal loads. SKH2 discs were coated with thin DLC films using a Physical Vapor Deposition (PVD) method. Tungsten (W) was used as an interlayer material. The DLC coated disc was impacted repeatedly by a chromium molybdenum steel (SCM420) pin. All impact tests were conducted at room temperature. It has been suggested that the deformation–wear transition map is an easy way to illustrate the impact wear mechanisms of DLC coating, as shown by its transition zones. Initially, the DLC coating only follows the plastic deformation of the substrate until several impact cycles. Then, a suppression of plastic deformation of the substrate is taking place due to the decreasing contact pressure with impact cycles to the yield point. Wear of the DLC coating becomes dominant when the critical limit of maximum normal impact load and impact cycles is exceeded. From experimental observations, some degradation of the DLC coating occurs within the wear zone.     

Evaluation of retained products of conception using pulsed continuous arterial spin-labeling MRI: clinical feasibility and initial results

Objectives

We evaluated the vascularity of retained products of conception (RPOC) using arterial spin-labeling magnetic resonance imaging (ASL-MRI) to clarify the clinical feasibility of this approach.

Materials and methods

A pulsed-continuous ASL sequence with echo-planar imaging (EPI) acquisitions was used. Ten consecutive patients with RPOC were enrolled. All ASL images were evaluated visually and semiquantitatively and compared with the findings of Doppler ultrasound (US) and dynamic contrast-enhanced MRI (DCE-MRI).

Results

The technical success rate was 93.7% (15/16 scans). One failed case was excluded from the analysis. Six patients showed quite high signals over RPOC, while three patients showed no abnormal signals. Doppler US alone failed to detect the hypervascular area in two cases, and ASL-MRI alone failed in three. A significant linear correlation was found between semiquantitative values of ASL-MRI and DCE-MRI. All six patients showing high signals on ASL-MRI underwent follow-up MRI after therapy. High signals in five patients decreased visually and semiquantitatively, while one patient showed signal increases.

Conclusion

Evaluation of RPOC using ASL-MRI was clinically feasible and response to therapy could be evaluated. However, the clinical advantages over conventional imaging remain unclear and need to be evaluated.

     

Single-crystal SiC thin-film produced by epitaxial growth and its application to micro-mechanical devices

This paper deals with the fabrication process of single-crystal silicon carbide (SiC) thin-films and its application to microdevice. SiC thin-film was synthesized using molecular beam epitaxy, where single-crystal SiC layer was grown on single-crystal silicon (Si) substrate. Using lithography and etching process, microscopic cantilevers were fabricated. Typical dimensions of the cantilevers were 10-60 μm in length, 10-30 μm in width, typically 180 nm in thickness. Young's modulus estimated from bending test was almost the same with that of bulk material. Finally, an application is demonstrated where nickel was deposited on the cantilever and biomorphic actuation was carried out. The displacement at the tip was about 2 μm when the temperature change was 40 K. The time constant of the step response was about 0.07 s.     

Nucleation and initial growth processes of diamond thin films for stripper foils

Carbon ion beam stripper foils were fabricated from diamond films synthesized on silicon via chemical vapor deposition. Fine-grained polycrystal diamond foils with decent surface flatness were obtained using a nucleation enhancement pretreatment process. Freestanding diamond foils were formed by etching a portion of the silicon substrate on which the diamond films well-adhered. In preliminary lifetime evaluations, the 1–3 μm-thick diamond foils lasted between 20 and 420 min for 3.2 MeV Ne⁺ion-beam charge stripping.     

Effects of glass components on crystallization and dielectric properties of BST glass–ceramics

Crystallization behavior was studied for glass powders in which some portions of AlF₃ in the net composition of 60(Ba_0.7Sr_0.3)TiO₃–25SiO₂–15AlF₃ were replaced with Ga₂O₃ or Bi₂O₃. The replacement with Ga₂O₃ resulted in a progressive increase in crystallization temperature, which effectively assisted the viscous sintering of glass powders to produce densified BST glass–ceramics at relatively lower temperatures. For the Bi₂O₃-replaced glass powders, an increasing amount of Bi₂O₃ replacement lowered the crystallization temperature and yielded less densified glass–ceramics containing a considerable amount of glassy phase. The temperature dependence of permittivity was estimated for the Ga₂O₃- and Bi₂O₃-replaced glass–ceramics as a function of sintering conditions and the amount of replacement, respectively.     

Application of Ozonation to Dyeing Wastewater Treatment—Case Study in Nishiwaki Treatment Plant

Three treatment methods, raw wastewater (RW)?→?coagulation?→?biological treatment (RCB), RW→?pre-ozonation?→?biological treatment (ROB) and RW?→?biological treatment?→?post-ozonation (RBO), were investigated to clarify their effectiveness in treating dyeing wastewater from a treatment plant. The decrease in dissolved organic carbon (DOC) was in the following order: RCB?≥?RBO?>?ROB. DOC removal of 200 mg/L by biological treatment of RW was clearly higher than that of 12 mg/L by ozonation. On the other hand, only DOC removal of 108 mg/L was observed by biological treatment in RW after ozonation. The decrease in biological oxygen demand (BOD₅) was in the following order: ROB?≥?RCB?>?RBO. Because of the enhancement of biodegradability brought about by ozonation, BOD₅ after ozonation in RBO was higher than that of RW after biological treatment. Color was effectively removed by ozonation for both RW and RW after biological treatment, and the decrease in color was in the following order: RBO?>?ROB?≥?RCB. Adsorbable organic halide formation potential (AOXFP) and toxicity unit (TU15, exposure time is 15 min) were more effectively decreased by biological treatment than by coagulation or ozonation, although the differences among RCB, ROB and RBO were very small.     

Simultaneous determination of dichlorvos and trichlorfon in agricultural products by GC-FPD

We studied a gas chromatographic method for the determination of dichlorvos (DDVP) and trichlorfon (DEP) in agricultural products. DDVP and DEP were extracted from agricultural products with acetone and re-extracted with ethyl acetate instead of dichloromethane. DDVP and DEP were eluted in one fraction on a silica gel column using n-hexane-acetone (1:1). DEP is a thermally labile compound, so it was derived to a more thermally stable compound by acylation with N-methylbis(trifluoroacetamide) and pyridine in acetone at 60 degrees C for 2 hours. DDVP and the DEP-TFA derivative were determined simultaneously by GC-FPD. The recoveries of DDVP and DEP from agricultural products spiked at levels of 0.1 microgram/g were 72.6-117.7% and 86.2-106.6%, respectively. The detection limits were 0.03 microgram/g in powdered tea and < or = 0.01 microgram/g in other samples. An interlaboratory study by 6 laboratories was conducted to validate this proposed method for 6 crops. Repeatability ranged from 3.1 to 7.8% for DDVP and from 3.4 to 8.3% for DEP, and reproducibility, from 6.9 to 15.5% for DDVP, and from 7.9 to 21.8% for DEP. Precision values were well within statistically predicted levels.     

Effects of engineered methionine in the 8Sα globulin of mungbean on its physicochemical and functional properties and potential nutritional quality

The major storage protein of mungbean, 8Sα globulin or vicilin, was engineered using site-directed mutagenesis to increase the number of methionine (Met) residues in the molecule for improvement of functional and nutritional qualities. Eight Met-rich proteins were designed and prepared to have 2 to 10 Met residues introduced in disordered regions II and IV. The designed proteins were highly expressed as soluble form in Escherichia coli. Their production level of the modified proteins was estimated to be about 30%, and was almost the same as that of 8Sα globulin wild type (WT). The modified proteins formed stable native conformation similar to WT as shown by gel filtration chromatography. They demonstrated greater stability in terms of thermal denaturation temperature and greater emulsifying ability and emulsion stability, especially the 10-Met protein, compared to the wild type. Met-rich proteins with 3, 5, and 10 Met residues had 74, 96, and 145% of nutritional requirement for Met compared with 41% for WT. Based on allergenicity prediction programs, WT and all the modified proteins had no allergenic potential.