Simultaneous measurement of the resistivity and permeability of afilm sample with a double coil

A method is proposed for a simultaneous measurement of the resistivity and permeability of a film inserted between two coils facing each other. Connecting in series, the total impedance of the coils was measured in two ways, i.e., 1) the current passes through the coils in the same direction, and 2) the current passes through each coil in opposite directions to each other. The resistivity and permeability of the film were simultaneously obtained from the difference in the impedance for the two cases. It was theoretically found that the optimum frequency for high accuracy in the measurement was proportional to the resistivity and inversely proportional to a thickness of a sample film. The results of the simultaneous measurements of the resistivity and permeability of nickel films of a thickness ranging from 0.01-0.08 mm at a frequency range of 1-100 kHz are shown in this paper. The measured values of the resistivity and permeability with this method agreed with the values obtained by conventional methods, i.e., the dc four-probe method for the resistivity measurement and the toroidal coil method for the permeability measurement     

UTP induces vascular responses in the isolated and perfused canine epicardial coronary artery via UTP-preferring P2Y receptors

1. Vasoconstrictor responses of the isolated and perfused canine epicardial coronary artery to uridine 5'-triphosphate (UTP) were analysed pharmacologically. 2. At basal perfusion pressure, UTP induced vasoconstriction in a dose-related manner and the vasoconstriction was sometimes followed by a slight vasodilatation at large doses (more than 10 nmol). The rank order of potency for vasoconstriction was UTP = UDP > ATP > TTP > or = ITP > UMP. At raised perfusion pressure by 20 mM KCl, the vasoconstriction was not changed and a small vasodilatation was induced at large doses. The rank order of potency for vasodilatation was induced at large doses. The rank order of potency for vasodilatation was ATP > ITP > or = UDP > UTP > or = TTP. The maximal vasodilator response to UTP was much less than that to ATP. UMP did not induce vasodilatation. 3. The P2X receptor agonist and desensitizing agent alpha, beta-methylene ATP (1 microM) and the P2 receptor antagonist suramin (100 microM) inhibited the vasoconstrictor responses to ATP but not those to UTP and UDP. The P2 receptor antagonist reactive blue 2 (30 microM) did not inhibit the vascular responses to UTP. 4. UTP (200 microM) desensitized the vasoconstrictor responses to UTP, but not either the vasodilator responses to UTP or the vasoconstrictor responses to ATP and UDP. UDP (200 microM) did not desensitize the vascular responses to UTP. 5. Preincubating the UDP stock solution and arterial preparation with hexokinase (10 and 1 uml-1, respectively) did not change the vasoconstrictor responses to UDP. 6. The Ca channel blocker diltiazem (1 microM) inhibited the vasoconstrictor responses to UTP but not those to ATP and UDP. Incubation in a Ca(2+)-free solution containing 1 mM EGTA inhibited the vascular responses to ATP, UTP and UDP. 7. Removal of the endothelium by an intraluminal injection of saponin (1 mg) inhibited the vasodilator responses to UTP. Indomethacin, a cyclo-oxygenase inhibitor (1 microM), inhibited the vasodilator responses to UTP, but NG-nitro-L-arginine, a nitric oxide synthase inhibitor (300 microM), did not have an inhibitory effect. 8. The results suggest that (1) UTP induces vasoconstriction via UTP-preferring P2Y receptors on the smooth muscle and vasodilatation via receptors different from those mediating the vasoconstriction induced by UTP and mediating the vasodilatation by ATP on the endothelium, through mainly the release of prostacyclin in the canine epicardial coronary artery; (2) UDP induces vasoconstriction via UDP-preferring P2Y receptors; and (3) L-type Ca ion channels are involved in the vasoconstriction induced by UTP, but not in that induced by UDP.     

Measurement of the magnetic susceptibility of a rod-shapedsuperconductor using a solenoid coil (SRPM method)

An effective method for the measurement of the magnetic susceptibility (χ) of a circular rod-shaped superconductor, in which χ is estimated by substituting the magnetic penetration depth (λ) into a formula after obtaining λ from the difference in the impedance between a solenoid coil with a sample and an identical one without a sample, is proposed. The temperature dependence of χ obtained from this method has correlated well with the values measured with a SQUID magnetometer     

A carboxyalkanethiol monolayer modified electrode for blocking of ascorbic acid oxidation and its application to a biosensor

Upon the application of amperometric biosensor to the biological fluid, ascorbic acid interferes the amperometric determination of analytes, because the oxidative potential of ascorbic acid is lower than that of electro active substances such as H₂O₂ produced by the enzymatic reaction. In this study we propose a method to block ascorbic acid based on the electrostatic interaction with self-assembled monolayer (SAM) and its application of the surface modified electrode to biosensor. In order to form SAM on the gold electrode with carboxyl group, 7-carboxy-heptanethiol (7-CHT) was used. The 7-CHT modified electrode did not show anodic response to ascorbic acid, but oxidized phenanthroline cobalt complex [Co(phen)₃²⁺], which can be used as a mediator of biosensor. Thus, the 7CHT-modified electrode was applied to biosensor mediated with Co(phen)₃²⁺. Fructose dehydrogenase (FDH) was immobilized to the 7-CHT modified electrode. Fructose was determined selectively with the FDH/7-CHT modified electrode at the range of 0.2-2 mM.     

Preparation of 6FDA-based polyimide composite membrane by CVDP process

Preparation of polyimide composite membranes by a chemical vapor deposition and polymerization process (CVDP) was studied for the development of pervaporation or gas separation membranes. Hexafluoroisopropylidene-2,2-bis [phethalic acid anhydride] (6F-dianhydride) (6FDA) and 4,4′-diaminodiphenyl ether (ODA) were used as monomers and were simultaneously deposited on an asymmetric polyimide membrane in vacuum of 10⁻⁶ Torr. The deposited layer of the monomers was converted to polyimide by heating at 250°C at 3 h in an ordinary vacuum oven, and its separation performance for water-ethanol and CO₂−N₂ systems was characterized.     

Plasma developable photoresist containing electronic excitation energy quenching system

A dry developable negative working resist composition comprised of poly(methyl isopropenyl ketone) (PMIPK) and 4-methyl-2,6-di(4′-azido-benzylidene) cyclohexanone-1 was examined. The main photochemical product formed in the resist pattern was found to be a secondary amine which crosslinks PMIPK. Post-annealing forms a hydrogen-bonded product which shows a powerful electronic excitation energy quenching effect. The quencher is more powerful than the aromatic compound arising from the azide by post-annealing only. The residual resist thickness of the negative pattern is about 80 percent of the initial thickness of the coating in spite of all the azide compound remaining in the resist coating. The obtained dry developed resist pattern has a high dry etch resistance. Etchings of Si and SiO₂ were performed by plasma and reactive ion etching, respectively.     

Porous poly(L‐lactic acid)/poly(ethylene glycol) blend films

Poly(L ‐lactic acid) (PLLA: M_w = 19.4 × 10⁴)/poly(ethylene glycol) (PEG: M_w = 400) blend films were formed by use of a solvent‐cast technique. The properties and structures of these blend films were investigated. The Young's modulus of the PLLA decreased from 1220 to 417 MPa with the addition of PEG 5 wt %, but the elongation at break increased from 19 to 126%. The melting point of PLLA linearly decreased with increases in the PEG content (i.e., pure PLLA: 172.5°C, PLLA/PEG = 60/40 wt %: 159.6°C). The PEG 20 wt % blend film had a porous structure. The pore diameter was 3–5 μm. The alkali hydrolysis rate of this blend film was accelerated due to its porous structure. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 965–970, 2004     

Preparation of SiC-based cellular substrate by pressure-pulsed chemical vapor infiltration into honeycomb-shaped paper preforms

Using a pressure-pulsed chemical vapor infiltration technique, SiC was infiltrated from a SiCl₄ (4%)–CH₄ (4%)–H₂ gas phase into carbonized paper preforms at 1100°C. SiC-based cellular substrates with cell wall thicknesses of 25, 50 and 100 m were obtained by using honeycomb-shaped paper preforms as the templates. The reduction of both wall thickness t and cell pitch d of SiC-based honeycomb substrate successfully led to an increase in geometric surface area per unit volume S, keeping pressure drop P at constant, besides; P decreased without lowering S by the reduction of t and the increase in d. The pressure drop in the prepared honeycomb substrates depended on S ^2–3 value, where was open frontal area fraction. The compressive strength of the honeycomb substrates with t of 25 m was about 7 MPa. The strength increased in proportion with 1 – , which corresponded to the volume fraction of the cell wall in the honeycomb substrate.     

Autonomous cell death of mouse male germ cells during fetal and postnatal period

OBJECTIVE: To determine the utility of CT-determined main pulmonary artery diameter (MPAD) for predicting pulmonary hypertension (PH) in patients with parenchymal lung disease. DESIGN: Retrospective review of right-heart hemodynamic data and chest CT scans in 45 patients. SETTING: Tertiary-referral teaching hospital and VA hospital. PATIENTS: Between October 1990 and December 1995, 36 patients referred for evaluation of parenchymal lung disease or possible pulmonary vascular disease were found to have PH, as defined by mean pulmonary artery pressure (mPAP) > or =20 mm Hg. Nine control patients (mPAP <20 mm Hg) were also identified (4 from hospital records search, 5 after evaluation for possible PH). RESULTS: CT-determined MPAD was 35+/-6 mm in patients with PH and 27+/-2 mm in control subjects. In our group of patients, MPAD > or =29 mm had a sensitivity of 87%, specificity of 89%, positive predictive value (PPV) of 0.97, and positive likelihood ratio (LR) of 7.91 for predicting PH; in the subgroup of patients with parenchymal lung disease (n=28, PH and control subjects), MPAD > or =29 mm had a sensitivity of 84%, specificity of 75%, PPV of 0.95, and positive LR of 3.36 for predicting PH. The most specific findings for the presence of PH were both MPAD > or =29 mm and segmental artery-to-bronchus ratio > 1:1 in three or four lobes (specificity, 100%). There was no linear correlation between the degree of PH and MPAD (r=0.124). CONCLUSIONS: CT-determined MPAD has excellent diagnostic value for detection of PH in patients with advanced lung disease. Therefore, standard chest CT scans can be used to screen for PH as a cause of exertional limitation in patients with parenchymal lung disease. Because CT is commonly used to evaluate parenchymal lung disease, this information is readily available.