Rate acceleration of Diels–Alder reactions utilizing a fluorous micellar system in water

A fluorous micellar system in water has been created to produce a large interfacial area between these media that retains substrates, effectively facilitating intermolecular Diels–Alder reactions due to repulsion effects from both media. Because LiFOS functioned not only as a surfactant but also as a supporting electrolyte, an electrochemical approach could be introduced to evaluate the rate acceleration effects. The measurement of the particle size distribution of the fluorous micelles clearly supported these evaluations.     

A method of determining the advanced angle of square-wave currentsin a bearingless switched reluctance motor

Bearingless switched reluctance motors, which can control rotor radial positions with magnetic force, have been proposed. These motors have combined the characteristics of switched reluctance motors and magnetic bearings. This paper proposes a method of determining the advanced angle of square-wave currents in a bearingless switched reluctance motor. Under any torque condition, from no load to full load, stable operation is realized by controlling the advanced angle of square-wave currents with the proposed method. It is shown experimentally that the proposed method is effective in realizing stable operation     

Observation of metal on Si(0 0 1) by STM/STS and its consideration based on the first principles calculations

Local density of states (LDOS) is obtained by the first principles calculation based on the density functional theory on the Si(0 0 1)2 × 1 surface and on the surface with an Al dimer. At an Al dimer, LDOS has a high intensity in the conduction band region, which cannot be seen on the Si(0 0 1)2 × 1 surface. This tendency is observed in STS measurements as well. The possibility for a microelementary analysis is presented by applying this method to other metal atoms on the Si surface. Furthermore, it is pointed out that STS measurements should be always performed at the same tip-sample separation to obtain reproducible STS spectrums.     

Very high temperature annealing effect on amorphous carbon films grown on refractory oxide substrates by pulsed laser deposition

We have carried out very high temperature heat treatment at 1400–2700 °C of about 10 nm-thick amorphous carbon thin films deposited on refractory substrates MgO, Al₂O₃, and yttria-stabilized zirconia (YSZ) using pulsed laser deposition techniques. After the annealing, a few nanometer scale sp² crystallization of the films and a large corrugation with a height of more than 1 μm were observed by Raman spectroscopy analysis and optical/atomic force microscopes, respectively. The corrugation is probably caused by the formation of gases at the film/substrate interface during the heat treatment.     

Clinical survey of congenital cytomegalovirus infection in Japan

Contrast media-induced nephropathy is one of the leading causes of hospital-acquired renal failure, occurring most frequently in patients with pre-existing renal insufficiency. We prospectively studied 55 patients with chronic renal insufficiency (serum creatinine concentration 1.4 to 3.5 mg/dl) who underwent abdominal aortography and arteriography of the lower extremities. The patients were randomized into two groups. Group 1, 28 patients, received dopamine 2.5 mcg/kg beginning 1 hour before arteriography and continuing for 12 hours. Group 2 received an equal volume of saline for the same period of time. Serum creatinine and 12-hour creatinine clearance were measured before arteriography and for 4 consecutive days afterward. Acute contrast-induced decrease in renal function was defined as increase in the baseline serum creatinine concentration > or = 0.5 mg/dl. On day 1 postarteriography the serum creatinine increased from baseline .193 mg/dl for controls while the dopamine group decreased slightly from baseline .018 mg/dl (p = 0.002). Excepting day 1 postarteriography, there was no statistical difference between groups, and serum levels for both groups increased linearly from baseline across time (dopamine p = 0.028, control p = 0.025). In patients with pre-arteriography baseline serum levels greater than or equal to 2.0 mg/dl, however, the increase in serum creatinine from baseline levels was consistently and significantly greater in the control group through the fourth day (0.012 < or = p < or = 0.049). Creatinine clearance did not change significantly from baseline after arteriography in the dopamine group (baseline versus days 1 through 4, 0.238 < or = p < or = 0.968); however, the control group showed a significant linear decrease in creatinine clearance from baseline through the fourth day after arteriography (p = 0.016). Dopamine infusion prevented a rise in serum creatinine 24 hours after angiography in patients with pre-existing renal insufficiency, and protected against contrast-induced decrease in renal function in patients whose baseline serum creatinine was > or = 2.0 mg/dl.     

Degradation of a Victorian brown coal in sub-critical water

Conversion characteristics of a Victorian brown coal in sub-critical water were investigated. Pulverized brown coal was heated up to 623 K in flowing sub-critical water pressurized at 25 MPa. The total conversion of the coal into extract and non-condensable gas reached over 70 wt%-daf, which was appreciably higher than the maximum conversion (50 wt%-daf) with a sub-critical non-hydrogen donor solvent, 1-methylnaphthalene (MN). Laser-ionization-desorption mass spectrometry showed that the sub-critical water extract was richer in lower-molecular-mass compounds than the sub-critical MN one. Thus, degradation of the coal occurred more extensively in sub-critical water than in MN. Along with the conversion in sub-critical water, both the total contents of hydrogen and phenolic hydroxyls in the whole products remained nearly unchanged. This suggests comparable and simultaneous formation and decomposition of hydroxyls through hydrolysis of ethers/esters and dehydration condensation between hydroxyls/carboxyls, respectively. For detecting the hydroxyl formation, the coal was first heated at 623 K under an inert gas atmosphere until the formation of water and the other volatiles was completed. Then, the heat-treated coal (LY-H) was exposed to flowing sub-critical water. As expected, the net formation of phenolic hydroxyls from LY-H was detected as 0.8 mmol-OH/g-LY-H while that of hydrogen as 2.3 mmol-H/g-LY-H. Approximately a half of the hydrogen gain was explained as phenolic hydroxyls gain, suggesting the importance of hydrolysis of esters and ethers that formed carboxyls and alcoholic hydroxyls as well as phenolic hydroxyls.