Enzymatic assay method for measuring mizoribine levels in serum

A sensitive and specific method for assaying serum mizoribine levels that can be applied to general automatic clinical analyzers was developed. Regression analysis of the enzymatic assay (y) vs. the HPLC method (x) produced the following relation: y=0.964x+0.090 (n=262, Sy, x=6.37 ng/mL).     

Degradation of phenolic compounds in water by non-thermal plasma treatment

A stainless-steel hollow needle type anode was used in the reactor to treat industrial wastewater by gas-liquid phase of non-thermal plasma by corona discharge. The results showed that the short electrode gap, 1 cm, has a higher plasma energy density which improves the removal of the phenolic derivatives, reaching 100% after about 60 min. The H₂O₂ concentration was higher in the discharge system when the content of oxygen was increased. The efficiency of the phenol removal by chemical oxygen demand was only 10?C31% after 60 minutes. The identified intermediates were catechol, hydroquinone, 1,4-benzoquinone, 2-nitrophenol, 1,2-benzenedicarboxylic acid, diphenylmethanone, 2-methyl-hydroquinone, 2-methyl-1,4-bezoquinone, and trace amounts of organic.     

Utilization of (oxalato)borate-based organic electrolytes in activated carbon/graphite capacitors

The electrolyte salts composed of tetramethylammonium (TMA⁺) cation and difluoro(oxalato)borate (DFOB⁻) or bis(oxalato)borate (BOB⁻) anions have been proposed for the application in activated carbon (AC)/graphite capacitors. The electrochemical performance of AC/graphite capacitors has been studied using these electrolyte salts dissolved in propylene carbonate (PC). The intercalation behaviors of anions (BF₄⁻, DFOB⁻, and BOB⁻) at the graphite positive electrodes have been investigated by in situ XRD measurements. The bigger the anion is, the higher the cell voltage is where the intercalation happens. Accordingly, the bigger the anion is, the smaller discharge capacity delivered by an AC/graphite capacitor. The charge mechanism of TMA⁺ at the AC negative side has also been addressed. Compared with other bigger quaternary alkyl ammonium cations, the specific capacitance of the AC negative electrode towards TMA⁺ adsorption is somehow smaller as estimated.     

Electrochemical evaluation of the interaction between endocrine disrupter chemicals and estrogen receptor using 17,beta-estradiol labeled with daunomycin

A new electrochemical screening method for endocrine disrupting chemicals (EDCs) was developed. To evaluate the binding capacity of EDCs to the estrogen receptor (ER), 17beta-estradiol labeled with daunomycin as an electroactive compound was prepared. The electrochemical sensitivity of the prepared labeled estradiol (LE) was high, as compared with daunomycin. The interaction between LE and ER was observed by the decrease in the electrode response of LE, indicating the specific binding of LE with ER. The competitive reaction between LE and 17beta-estradiol for the limiting binding site on ER produced increases in the peak current of LE. The relative standard deviation at 1 x 10(-8) M 17beta-estradiol was about 10.0% (n = 7). The binding affinity between EDC and ER was also evaluated by comparison with 17beta-estradiol-ER interaction. Bisphenol A, p-nonylphenol and p,p'-DDT was used as a test compound. All test compounds demonstrated some ability to bind with ER. This electrochemical binding assay illustrates a new method for evaluating the binding capacity of EDCs to ER without the need for a separation procedure for the bound and free LE.     

Computer-aided system for the diagnosis of Alzheimer's disease

One of the most serious problems in medical science is an increment of Alzheimer's disease. It is known that the patient's brain atrophy is a result of neural cell loss. It is useful for the diagnosis of Alzheimer's disease to measure the volumes of the brain portions and to display them. We can obtain anatomical information from 2D slice images produced by MRI. We propose a computer-aided system for the diagnosis of Alzheimer's disease. The system consists of: (1) extraction of the portions from MRI data, (2) measurement of the volumes of the portions and then displaying them, and (3) user interface for a medical doctor. In this paper we describe procedures for the above. For extraction of the brain portions we propose the method based on standard region growing algorithm and the method of figure decomposition using the distance value. Comparison of the volumes of our extracted portions with volumes manually measured by a physician shows that the error rate, on the average, is 1.74% for 48 MRI data. We also discuss the 3D display, the measuring range, and the construction of the user interface for a physician. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 119(4): 32–41, 1997     

New PWM Method for Fully Digitized Inverters

The development of digital devices has led to the production of PWM inverters for driving induction motors having high-frequency carriers over 10 000 Hz. However, the popular digital devices exhibit difficulties in arriving at the precise switching instants because of limitation of available memory capacity and of bits, especially in the low-frequency region. Basic discussions on the magnetic flux and torque ripple and an introduction to a memory-saving and low-torque-ripple new PWM (split zero vector) method are given. The experiments show fairly good current waveforms, low iron loss, and low acoustic noise.     

Silica-based solvent impregnated adsorbents for separation of rare earth metals

Silica-based solvent impregnated adsorbents are prepared, employing 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester as an extractant. Two kinds of silica particles are used as supports; (i) those whose surface is coated by a styrene/divinylbenzene copolymer and (ii) those whose hydroxyl-terminated pentadimethyl siloxane group is immobilized on the surface. The adsorbent based on silica particles coated by styrene/divinylbenzene can be repeatedly used for adsorption–elution processing, while the adsorption capacity of the adsorbent based on silica particles modified by the siloxane group is decreased by repeated cycles. The adsorbent is applicable to chromatographic operation for Dy/Nd, and quantitative adsorption–elution is achieved.     

Separation and Recovery of Tetramethyl Ammonium Hydroxide with Mesoporous Silica Having a Hexagonal Structure (MCM-41)

Separation and recovery of tetramethyl ammonium hydroxide (TMAH) was investigated using several types of MCM-41 (mesoporous silica having hexagonal structure) adsorbents. The MCM-41s were prepared by hydrothermal synthesis with structure-directing agents with different alkyl chains. The prepared MCM-41s were characterized with X-ray diffraction, transmission electron microscope, nitrogen gas adsorption, and zeta potential, and then used for adsorption of TMAH. The adsorption of TMAH with MCM-41s increased with pH up to pH ≈ 10 and then decreased as the MCM-41 dissolved. The adsorption of TMAH progressed via the Langmuir mechanism. The maximum adsorption corresponded to the pore diameter and the pore volume of the MCM-41s. MCM-41 also possesses selectivity for TMAH against phenol. The chromatographic operation was conducted using granulated MCM-41 to avoid excessive pressure-drop through the packed column and quantitative adsorption-elution processing of TMAH could be achieved.     

Characteristics and management of the Sumikawa geothermal reservoir, northeastern Japan

The subsurface temperature gradually increases southward in the Sumikawa geothermal field and decreases sharply toward the north. The geothermal reservoir contains a two-phase zone between the cap rock and hot water zone. The target for production was designated in the deep zone, in the high temperature southern area. The production and reinjection areas have been separated to recover thermal energy efficiently during the recycling of reinjection fluid; the wells have been spaced as far apart as possible to reduce well interference. To improve productivity and injectivity, cold-water well stimulation was applied, and this experiment reduced the number of wells required for 50 MW_e power generation.