Triacylglycerol analysis of pequi (Caryocar brasiliensis Camb.) oil by electrospray and tandem mass spectrometry

Electrospray ionization liquid chromatography/tandem mass spectrometry was used to identify the fatty acid and triacylglycerol (TAG) composition of pequi (Caryocar brasiliensis Camb.) oil. The fatty acid composition was relatively simple; the oil contained approximately 442 and 517 g kg^?1 of palmitic and oleic acids respectively. Linoleic and stearic acids were found in much smaller amounts. The TAG composition of pequi oil is also relatively simple with trioleoyl glycerol (OOO, 56 g kg^?1), palmitoyl dioleoyl glycerol (POO, 466 g kg^?1) and dipalmitoyl oleoyl glycerol (POP, 452 g kg^?1) comprising 974 g kg^?1 of the total. Dioleoyl stearoyl glycerol (OOS) was found in small amounts (5.2 g kg^?1). All TAGs were identified via sodium adduct molecular ions [M + Na]⁺, where M is the TAG in question. Tandem mass analysis provided a very useful fragmentation pattern showing both sodium adduct diacylglycerol ions and diacylglycerol ions with the neutral loss of fatty acid residues. Copyright © 2005 Society of Chemical Industry     

The effect of substrate temperature on the spray-deposited TiO2 nanostructured films for dye-sensitized solar cells

The nanostructured TiO2 films have deposited on SnO2:F (FTO) coated glass substrate by spray pyrolysis technique at different substrate temperatures of 200-500 degrees C. The structural, surface morphological and optical properties of TiO2 films significantly vary with the substrate temperature. The surface of the TiO2 films deposited at 400 degrees C shows the nanoflakes and short nanorods (approximately 130 nm) like structures while the TiO2 films prepared at 500 degrees C shows only the nanoflakes like structures. The band gap of the TiO2 films prepared at higher temperatures (300-500 degrees C) becomes narrow due to presence the rutile phases in their crystal structure. Ruthenium (II) complex as a dye, KI/I2 as an electrolyte and carbon on FTO glass as a counter electrode has used to fabricate the dye-sensitized solar cell (DSC). The TiO2 film deposited at 400 degrees C has showed the best photovoltaic performance in DSC with the efficiency of 3.81%, the photovoltage of 773 mV, the photocurrent of 8.34 mA/cm2, and the fill factor of 56.17%. The photovoltage of the DSC increases with the increase of substrate temperature during the deposition of TiO2 films. Moreover, all the DSCs exhibit reasonably high fill factor value.     

Electron tunneling in MIS capacitors with the MBE-grown fluoride layers on Si(1 1 1) and Ge(1 1 1): Role of transverse momentum conservation

The current-voltage characteristics of the metal-insulator-semiconductor tunneling structures with calcium fluoride are simulated using different theoretical models. The results are compared to the data of current measurements on the fabricated capacitors with 1-3 nm epitaxial fluorides. Best agreement is achieved imposing a condition of transverse momentum k_⊥ conservation for a tunneling electron. This fact may be treated as an experimental proof for the k_⊥ conservation in the examined high-quality structures which was not directly confirmed on more traditional structures with oxide dielectrics.     

Study on corrosion of welded steel for LBE-cooled fast reactors

Lead-bismuth eutectic (LBE) is a candidate coolant for fast reactors. Its physical, chemical and neutronic properties make it a prospect coolant for the reactors. However, corrosion of structure is the main problem of utilizing LBE as a coolant. Compatibility of welded structure with LBE at high temperature should be considered clearly for feasibility of lead-bismuth-cooled fast reactors. This study was preformed to investigate the mechanical properties and corrosion characteristics of the welded ferritic-martensitic (FM) steel, HCM12A, in LBE at 650 °C for 500 h. The welding methods were TIG welding (137 mm/min; 480 W), YAG laser welding (780 mm/min; 287 W) and electron beam welding (1000 mm/min; 60 kW). The oxygen concentration of test environment was maintained at 7 x 10⁻⁷ wt% by injecting Ar-H2-steam gas mixture. Vickers hardness test and SEM/EDX analysis were conducted on the cross section of welded HCM12A. It was found that oxide layer was larger in the weld zones than base metal (BM). However, outer layer was detached on some areas.     

Corrosion resistance of ceramics SiC and Si3N4 in flowing lead-bismuth eutectic

A corrosion test was conducted to investigate the corrosion characteristics of SiC and Si₃N₄ in a flowing lead-bismuth eutectic (Pb-Bi) with a fluid temperature of 550 °C, a velocity of 1 m/s, and an oxygen concentration of 1 × 10⁻⁶ wt% for an exposure time of 2000 h. The weight losses of the SiC and Si₃N₄ specimens were lower than those of corrosion-resistant steels tested under the same condition. The specimens showed excellent resistance against an element dissolution and an oxidation in the Pb-Bi flow. The surface was slightly damaged due to some stresses of the Pb-Bi flow and/or those generated by adhered Pb-Bi in the test procedure.     

Progress in ECRF antenna development for JT-60SA

Structural, mechanical and optical design work on antennas/launchers for the electron cyclotron range of frequency heating and current drive system in JT-60 Super Advanced (JT-60SA) have been advanced based on a linear motion antenna concept. A CAD model of the launcher was built with realistic component sizes. A mock-up of the steering structure consisting of two different bellows sections for poloidal and toroidal beam scanning was fabricated to test movement of the bellows. The poloidal (?40° to +20°) and toroidal (?15° to +15°) injection angle ranges required in JT-60SA were shown to be realized by this steering structure and mirrors.     

Dioxin-like and transthyretin-binding compounds in indoor dusts collected from Japan: average daily dose and possible implications for children

Many researchers are increasingly interested in human exposure to house dust containing household compounds such as polybrominated diphenylethers (PBDEs). Nevertheless, no investigations have addressed the endocrine-disrupting potencies of compounds contained in indoor dust. This study specifically addresses endocrine-disrupting potencies such as dioxin-like activity and human transthyretin (TTR)-binding potencies. Using in vitro bioassays, we investigated these activity levels in indoor dusts. We performed exposure assessments of active compounds that are contained in house dust for subsequent evaluation of house dusts' risks to humans. Dioxin-like and TTR-binding activities in sulfuric acid treatment extracts of house and office dust were investigated using Dioxin-Responsive Chemical-Activated LUciferase gene eXpression assay (DR-CALUX) and TTR-binding assay (in vitro competitive human TTR-binding assay). Dioxin-like activities in indoor dust were 38-1400 pg CALUX-TEQ (2,3,7,8-TCDD equivalent)/g (median 160 pg CALUX-TEQ/g) and TTR-binding potencies were 300-5000 pmol T4EQ (thyroxine (T4) equivalent)/g (median 1000 pmol T4EQ/g), which are higher values than those in other environmental samples, e.g., contaminated sediments. These exposure results suggest that children might be affected by both dioxin-like compounds and TTR-binding compounds via house dust. When the ingestion rate, CALUX-TEQ, and T4EQ for house dust are high, thyroid hormone homeostasis in children may be disrupted.     

Selection of acid tolerant bifidobacteria and evidence for a low-pH-inducible acid tolerance response in Bifidobacterium longum

Acidity is an environmental condition commonly encountered by lactic acid bacteria and bifidobacteria in the gastrointestinal tract and fermented foods. In the present study, 22 strains of Bifidobacterium were screened for acid tolerance in artificial gastric juice (AGJ, pH 3.0) and fermented milk. AGJ tolerance was found to be strain-specific, with a pronounced variation among the strains. Several strains with a high survival rate in AGJ that belonged to Bifid. longum, Bifid. breve and Bifid. adolescentis were selected. Among them, only strain BL1 of Bifid longum was found to possess a high survival rate in fermented milk during refrigerated storage. Strain BL1 exhibited a survival rate of more than 25% in AGJ at pH 3.0 for 2 h and maintained a viable cfu level of more than 10(8) per gram of product in fermented milk (pH 4.6) under refrigerated conditions for 2 weeks. The acid tolerance of strain BL1 was found to depend on the final growth pH (<4.5). Rapid loss of acid tolerance was observed when the cells were shifted from acid to neutral conditions by addition of NaOH. Strain BL1 cells were able to maintain much higher intracellular pH under acid conditions, in comparison with those of AGJ sensitive mutant (BL1-S) or cells that lost acid tolerance following pH shifting from acid to neutral conditions. These results suggested that a cytoplasmic pH homeostasis system may function in the acid tolerance response in this strain.