Characterization of the anatomical structures involved in the contractile response of the rat lung periphery

1. When lung parenchymal strips are challenged with different smooth muscle agonists, the tensile and viscoelastic properties change. It is not clear, however, which of the different anatomical elements present in the parenchymal strip, i.e., small vessel, small airway or alveolar wall, contribute to the response. 2. Parenchymal lung strips from Sprague Dawley rats were suspended in an organ bath filled with Krebs solution (37 degrees C, pH = 7.4) bubbled with 95%O2/5%CO2. Resting tension (T) was set at 1.1 g and sinusoidal oscillations of 2.5% resting length (L0) at a frequency of 1 Hz were applied. Following 1 h of stress adaptation, measurements of length (L) and T were recorded under baseline conditions and after challenge with a variety of pharmacological agents, i.e., acetylcholine (ACh), noradrenaline (NA) and angiotensin II (AII). Elastance (E) and resistance (R) were calculated by fitting changes in T, L and delta L/ delta t to the equation of motion. Hysteresivity (eta, the ratio of the energy dissipated to that conserved) was obtained from the equation eta = (R/E)2 pi f. 3. In order to determine whether small airways or small vessels accounted for the responses to the different pharmacologic agents, further studies were carried out in lung explants. Excised lungs from Sprague Dawley rats were inflated with agarose. Transverse slices of lung (0.5-1.0 mm thick) were cultured overnight. By use of an inverted microscope and video camera, airway and vascular lumen area were measured with an image analysis system. 4. NA, ACh and AII constricted the parenchymal strips. Airways constricted after all agonists, vessels constricted only after All. Atropine (Atr) pre-incubation decreased the explanted airway and vessel response to AII, but no difference was found in the parenchymal strip response. 5. Preincubation with the arginine analogue N omega-nitro-L-arginine (L-NOARG) did not modify the response to ACh but mildly increased the oscillatory response to NA after co-preincubation with propranolol (Prop). 6. These results suggest that during ACh and NA challenge, small vessels do not contribute substantially to the parenchymal strip response. The discrepancy between results in airways, vessels and strips when Atr was administered prior to AII implicates a direct contractile response in the parenchymal strip.     

A diagnostic technique to detect abnormal conditions of contactsmeasuring vibrations in metal enclosures of gas insulatedswitchgear

The diagnosis of abnormal conditions at current-conducting contacts by measuring the metal-enclosure vibrations of gas-insulated switchgear was studied experimentally and theoretically. Vibrations appeared when current flowed through artificially simulated abnormal contacts. Vibration peaks existed at frequencies which were integral values times the current frequency, especially between 400 Hz and 2 kHz. Vibration peak values increased as contact voltage increased above 400 Hz. Contact voltage waveforms in the stable state were distorted and their top peaks became sharp as the contact voltage increased. The reason for the distortion was the temperature rise which accompanied the alternating current change     

Modulation of cysteine biosynthesis in chloroplasts of transgenic tobacco overexpressing cysteine synthase [O-acetylserine(thiol)-lyase]

Cysteine synthase [O-acetyl-L-serine(thiol)-lyase, EC 4.2.99.8] (CSase), which is responsible for the terminal step of cysteine biosynthesis, catalyzes the formation of L-cysteine from O-acetyl-L-serine (OAS) and hydrogen sulfide. Three T-DNA vectors carrying a spinach (Spinacia oleracea) cytoplasmic CSase A cDNA (K. Saito, N. Miura, M. Yamazaki, H. Horano, I. Murakoshi [1992] Proc Natl Acad Sci USA 89: 8078-8082) were constructed as follows: pCSK3F, cDNA driven by the cauliflower mosaic virus (CaMV) 35S RNA promoter with a sense orientation; pCSK3R, cDNA driven by the CaMV 355 promoter with an antisense orientation; pCSK4F, cDNA fused with the sequence for chloroplast-targeting transit peptide of pea ribulose-1,5-biphosphate carboxylase small subunit driven by the CaMV 35S promoter with a sense orientation. These chimeric genes were transferred into tobacco (Nicotiana tabacum) with Agrobacterium-mediated transformation, and self-fertilized progeny were obtained. CSase activities in cell-free extracts of pCSK3F and pCSK4F transformants were 2- to 3-fold higher than those of control and pCSK3R plants. CSase activities in chloroplasts of pCSK4F transformants were severalfold higher than those of control and pCSK3F plants, indicating that the foreign CSase protein is transported and accumulated in a functionally active form in chloroplasts of pCSK4F plants. Isolated chloroplasts of a pCSK4F transformant had a more pronounced ability to form cysteine in response to addition of OAS and sulfur compounds than those of a control plant. In particular, feeding of OAS and sulfite resulted in enhanced cysteine formation, which required photoreduction of sulfite in chloroplasts. The enhanced cysteine formation in a pCSK4F plant responding to sulfite was also observed in leaf discs. In addition, these leaf discs were partially resistant to sulfite toxicity, possibly due to metabolic detoxification of sulfite by fixing into cysteine. These results suggested that overaccumulated foreign CSase in chloroplasts could modulate biosynthetic flow of cysteine in response to sulfur stress.     

Behavior of the Resonant Frequency Shift of the Quartz Crystal Microbalance in NaCl Solution

Abstract

We report the novel characteristics of the series resonant‐frequency shift (ΔF) of the single‐face sealed quartz crystal microbalance (QCM) in an electrolyte solution. In the present study, we used NaCl as an electrolyte. This study revealed that, in an electrolyte solution, the ΔF values vary linearly with an increase in the square root of the density‐viscosity product of the solution, and the immersion angle dependence of ΔF appears. Moreover, we have found that the intercept value of ΔF appears and is brought about by the electric double layer. We also suggest that the ΔF values are independent of the conductivity and the permittivity of the solution.     

Characteristics of a hybrid transducer-type ultrasonic motor

The hybrid transducer-type ultrasonic motor previously proposed by the authors (1989, 1991) uses two ultrasonic transducers to control the Lissajous figure at the contact surface of the stator. This motor is stable, even at low speed, and realizes a large output with a high efficiency due to the high controllability of the Lissajous figure. The experimental investigation of the characteristics of this hybrid transducer-type ultrasonic motor is presented. In addition, the maximum torque is roughly estimated by means of a simple model. The dependence of the diameter of the motor (transducer) on the maximum torque is discussed and demonstrated experimentally.     

An estimation of load characteristics of an ultrasonic motor by measuring transient responses

To measure the characteristics of ultrasonic motors, such as the maximum torque, torque-speed relationship and the frictional coefficient at the contact surface, a method in which the torque is calculated from the transient responses is proposed. The rise curve that is the transitional change in the rotor speed soon after turning on the motor gives the load characteristics, while the fall curve that is the decay of the rotor speed after turning off the motor yields the frictional coefficient of the contact surface. This method requires only a short time (the transient time of the motor) to complete the measurement. The relations between the transient responses, the load characteristics and the frictional force are analyzed, and the method is applied to a hybrid transducer type rotary motor and a traveling wave type linear motor.     

Hybrid transducer type ultrasonic motor

A type of ultrasonic motor whose stator is composed of a torsional vibrator and multilayered piezoelectric actuators is proposed and has been fabricated for trial. The stator is operated at the resonance frequency of the torsional vibration. The vibrator generates the mechanical output force and the actuators control the frictional force. The construction provides for arbitrary Lissajous's figures at the contacting surface and contributes to large mechanical output power with high efficiency and bidirectional motion. It also gives greater freedom of design. The prototype motor produced a maximum torque of 7 kg-cm and a maximum efficiency of 33%     

An ultrasonic motor using bending vibrations of a short cylinder

An ultrasonic motor using bending vibrations of a short cylinder with free-free ends is proposed, and its performance and efficiency are discussed. The motor is small in size and realizes a high mechanical output of more than 1 W. The general principle of the motor, which uses traveling waves, is as follows. When a traveling wave propagates along an elastic object, particles at the surface move elliptically. A movable object (a slider or a rotor) pressed to the elastic object may be caused to move due to the frictional forces between it and the surface. A motor based on this principal has been constructed and studied. The vibration mode used is found to have an undesirable radial component, which restricts the efficiency of the motor to about 10% at best. A large amount of the energy supplied is lost by the slippage owing to the existence of the undesirable component. It is concluded that to derive larger output power, the frictional material needs to be carefully chosen.     

Investigation of high-pressure micro jet technology as an alternative to diamond disc conditioning in ILD CMP

The efficacy of an alternative to conventional diamond conditioning in chemical mechanical planarization (CMP) was evaluated in this study. The high pressure micro jet (HPMJ) system sprays ultra-pure water (UPW) at pressures ranging from 10 to 20 MPa onto a CMP pad to clean the pad of slurry residue, remove embedded slurry particles, and re-establish pad asperities. The system is employed in an ex situ fashion and is compared to in situ and ex situ diamond conditioning as well as using no conditioning. Real-time frictional force acquisition allows for coefficient of friction (COF) analysis, which indicates the extent of pad wear. Removal rate analysis, SEM imagery, and pad surface profilometry are also used to evaluate HPMJ as an alternative conditioning technology. Removal rates significantly lower than those associated with diamond conditioning are obtained for the HPMJ system when UPW conditioning is directly followed by polishing. SEM imagery and pad profilimetry indicate these low HPMJ removal rates are due to differences in pad surface chemistry, not pad surface topography. Experiments including a 30 s silicon wafer polish with slurry following HPMJ conditioning to re-establish pad surface chemistry were performed and result in removal rates that are comparable to those obtained using ex situ conditioning. The removal rates obtained using HPMJ conditioning for relative wafer-platen velocities of 0.31 and 0.62 m/s are 8 and 1% higher than those obtained using ex situ diamond conditioning and 18% lower than those obtained using ex situ diamond conditioning for 0.93 m/s. The average COF values for HPMJ conditioning using the intermediate silicon wafer polishes are 15% lower than average COF values associated with ex situ diamond conditioning, suggesting a possible increase in pad life for the HPMJ system.