Molecular characterization of hydroxyl-terminated polybutadienes

A comparative study has been made on the functionality distribution of two hydroxyl terminated polybutadiene products which are used largely as prepolymers for sealants, adhesives, and solid propellants. They are known to possess nearly the same molecular characteristics. To this end, each product was fractionated into 17 fractions with different molecular weights by the preparative GPC technique. Sample fractions thus obtained were subjected to “polarity-controlled adsorption” thin-layer chromatography (TLC) to determine the functionality distribution. From these experimental results it was concluded that a decisive difference between these products consists in the functionality distribution, within a molecular weight range higher than 7000.     

Transverse Acoustic Response Measured by AC-cut Quartz Transducer in Superfluid Helium-3

No Heading The transverse acoustic response in the B phase of superfluid ³He has been measured using an AC-cut quartz transducer at a pressure of 17.0 bar. The measurements were performed by a CW bridge method at a frequency of 9.3 MHz utilizing a quadrature hybrid and a high-frequency lock-in amplifier. By sweeping frequency around the resonance frequency of the transducer, in-phase and quadrature responses of the resonance were obtained from the output of the lock-in amplifier. We successfully separated the quality factor and the resonance frequency. Quality factor of the transducer had a small dip just below T_c and increased as _n by cooling, while its resonance frequency decreased sharply at T_c and gradually recovered to the normal state value in the low temperature limit.PACS numbers: 67.57.Jj, 43.58.+z.     

In vivo scattering measurement of biological tissue by the use of a pyroelectric polymer transducer

We propose a new method, to our knowledge, for noninvasive scattering measurements of tissues by the use of a pyroelectric polymer transducer, poly(vinylidene fluoride trifluoroethylene) film. In this method, samples are irradiated with nanosecond, low-energy light pulses delivered from an optical fiber, and the pyroelectric signal induced by the diffuse reflectance is measured with a transducer. The signal is then converted into diffuse reflectance by use of a calibration factor. The validity of this method was confirmed by our measuring the scattering coefficient of a white acrylic resin within an accuracy of +/- 15%. We attempted to apply this method to the estimation of scattering coefficients of normal and burned skins in rats in vivo.     

Synthetic lipid A produces antitumor effect in a hamster pancreatic carcinoma model through production of tumor necrosis factor from activated macrophages

The antitumor effect and biological activities of a newly synthesized lipid A analogue (ONO-4007) were investigated in a hamster pancreatic carcinoma model. Marked and dose-dependent inhibition of tumor growth was achieved by i.p. injection twice a week for 3 weeks of 10, 30 or 50 mg/kg of ONO-4007. Endogenous tumor necrosis factor (TNF) activities induced by ONO-4007 were significantly greater in tumor than in serum, spleen and liver. TNF production by macrophages stimulated with ONO-4007 after culture was much greater when culture was performed in the presence of hamster pancreatic carcinoma cells (no cell-to-cell contact). It was further found that the cytotoxic activity of TNF secreted by macrophages cultured with cancer cells was inhibited in the presence of anti-TNF neutralizing antibodies. These findings suggest that ONO-4007 displays antitumor effects by stimulating production of endogenous TNF in tumor macrophages, possibly through activation by soluble macrophage-stimulating factors in cancer cells.     

Effects of protease inhibitors on binding of sperm to the vitelline coat of ascidian eggs: implications for participation of a proteasome (multicatalytic proteinase complex)

The relation between left-ventricular stroke volume (SV) and end-diastolic volume (EDV) was determined based on angiocardiographic measurements in 10 open-chest minipigs under varying filling conditions (blood letting or infusions). The results were compared with a theoretical relation calculated under the assumption of varying EDV but constancy of myocardial properties. In contrast to the linear increase of SV as a function of EDV as found in the animal experiments, the calculated curve reveals a maximum near the normal operating point with a decrease in the range of higher EDV. It can be concluded that the well-known increase of SV with increasing ventricular filling, beyond the normal EDV, is almost completely due to muscle physiological factors (mainly increase in Ca2+ sensitivity of the contractile apparatus), whereas the decrease of SV in the range of low filling pressure is mainly due to the geometrical conditions.     

Recoveries of post-tetanic twitch and train-of-four responses after administration of vecuronium with different inhalation anaesthetics and neuroleptanaesthesia

We have studied recovery of post-tetanic twitch (PTT) and train-of-four (TOF) responses after administration of vecuronium in 100 patients under different inhalation anaesthetics and neuroleptanaesthesia. Patients were allocated randomly to five groups of 20 patients each to receive: neuroleptanaesthesia (droperidol and fentanyl), halothane, isoflurane, enflurane or sevoflurane (1 MAC in nitrous oxide and oxygen). The times from initial administration of vecuronium 0.2 mg kg-1 to the first appearances of T1, T2, T3 and T4 differed significantly between groups. However, the intervals to the first appearance of PTT1, PTT10 and PTT20 did not differ significantly between groups.     

Tunable Photonic Crystal Fiber Couplers With a Thermo-Responsive Liquid Crystal Resonator

We theoretically address the thermo-optical response of multicore photonic crystal fiber (PCF) couplers infiltrated with nematic liquid crystals (LCs). The proposed PCF coupler consists of two identical cores separated by a third one which acts as a liquid crystal resonator. With an appropriate choice of the design parameters associated with the liquid crystal core, phase matching at a single wavelength can be achieved, thus enabling thermo-tunable narrow-band resonant directional coupling between the input and the output cores. The verification of the proposed coupler design is ensured through an accurate PCF analysis based on finite element and beam propagation methods. The enhanced thermo-optical properties of LC-based PCF couplers are highly attractive for photo-thermal sensing applications.     

Effect of in-flight particle behavior on the morphology of flame sprayed Er2O3 splats

The morphology and microstructure of splats impact the comprehensive capability of a new coating methodology called chelate flame spraying (CFS). This study addresses the quantitative characterization of the spread morphologies of flame sprayed Er₂O₃ splats directly deposited under different spray conditions on aluminum alloy substrates with a mirror finish. The influence of the in-flight particle temperature and velocity, carrier gas type, and carrier gas ratio on the solidification mechanism of molten droplets was investigated. Image analysis methods were employed to identify single splats from the morphology observed with field-emission scanning electron microscopy (FE-SEM). In addition, Er₂O₃ films were synthesized on an Al–Mg alloy (A5052) substrate using N₂ or O₂ as the carrier gas. When O₂ was used as the carrier gas, 109-μm-thick films were deposited on the A5052 substrate. The cross-sectional porosity of the films was 3.8%. In contrast, films with 101-μm thickness were synthesized on the A5052 substrate when N₂ was used as the carrier gas. The cross-sectional porosity of these films was 13.8%. The results showed that the carrier gas type (N₂) and carrier gas ratio had a significant effect on the flattening behavior of the molten droplets. A spraying method combined with multidimensional modes is proposed to control the morphology of the splats.