A 40-GHz D-type flip-flop using AlGaAs/GaAs HBT's

We report master-slave D-type flip-flop (D-FF) circuit implemented with AlGaAs/GaAs HBT's. The fabricated HBT's had an f_T of 107 GHz and an f_max of 110 GHz. To maximize the speed, the logic swing and transistor size in the IC were optimized. In the D-FF, to facilitate the high-speed testing, a selector circuit was integrated on the same chip. As a result, the operation of this IC was confirmed up to 40 GHz, which is the highest speed in D-FF     

DC to 40-GHz broad-band amplifiers using AlGaAs/GaAs HBT's

In this paper, we report two types of broad-band amplifiers implemented with AlGaAs/GaAs HBT's. One is a Darlington feedback amplifier and the other is a transimpedance amplifier. In the former circuit, a dc gain of 9.5 dB and a -3-dB bandwidth of 40 GHz were achieved. In the latter circuit, a transimpedance gain of 50 dBΩ and a -3-dB bandwidth of 27 GHz were achieved. To our best knowledge, they are the highest speed in each circuit configuration     

Effect of calcium chloride on vapor-liquid equilibria of alcohol-alcohol and alcohol-water binary systems

The vapor-liquid equilibria of three alcohol-alcohol binary mixtures (methanol-ethanol, methanol-1-propanol and ethanol-1-propanol) and three alcohol-water binary mixtures (methanol-water, ethanol-water and allyl alcohol-water) containing calcium chloride were measured at 298.15 K using a flow-type apparatus. The measured data of each ternary system were correlated by the use of a semi-empirical model proposed by Hála. It was found that the model with the optimal value of the exponent β = 5.0 in the electrostatic interaction term, originally given as 3/2 by Hála, gives reasonable prediction to all the systems in this study.     

Convergence of skin reflex and corticospinal effects in segmental and propriospinal pathways to forelimb motoneurones in the cat

The organization of facilitatory convergence from cutaneous afferents (Skin) and the corticospinal tract (pyramidal tract, Pyr) in pathways to forelimb motoneurones of mainly distal muscles was studied in anaesthetized cats by analysing postsynaptic potentials (PSPs), which were spatially facilitated by combinations of stimuli to the two sources at different time intervals. Conditioning Pyr volleys facilitated Skin-evoked PSPs of fixed (1.2-3.6 ms) central latencies (Skin PSPs), suggesting that disynaptic and polysynaptic skin reflex pathways are facilitated from the pyramidal tract. The shortest latencies (1.2-1.7 ms) of pyramidal facilitation suggested direct connection of pyramidal fibres with last order neurones of skin reflex pathways. Conditioning Skin volleys facilitated Pyr-evoked PSPs of fixed, mostly disynaptic latencies (1.0-2.5 ms; Pyr PSPs), suggesting that pyramido-motoneuronal pathways are facilitated from Skin at a premotoneuronal level. The shortest pathway from skin afferents to the premotor neurones appeared to be monosynaptic. Although Pyr and Skin volleys were mutually facilitating, the facilitation curve of Pyr PSPs and that of Skin PSPs were discontinuous to each other, with the peak facilitation at different Skin-Pyr volley intervals. Transection of the dorsal column (DC) at the C5/C6 border had little effect on the latencies or amplitudes evoked by maximal stimulation and the pyramidal facilitation of Skin PSPs. In contrast, the facilitation of Pyr PSPs by Skin stimulation was greatly decreased after the DC transection, and the facilitation curve of Pyr PSPs was continuous to that of Skin PSPs, with no separate peak. Latencies of Pyr PSPs ranged similarly to those in DC intact preparations. More rostral DC transection (C4/C5 border) reduced Skin-facilitated Pyr excitatory PSPs (EPSPs) less than C5/C6 lesions, suggesting that the C5 segment also contains neurones mediating Skin-facilitated Pyr EPSPs. The results show that convergence from skin afferents and the corticospinal tract occurs at premotor pathways of different cervical segments. We suggest that corticospinal facilitation of skin reflex occurs mostly in the brachial segments and Skin facilitation of cortico-motoneuronal effects takes place largely in the rostral cervical segments and partly in the brachial segments.     

Relevant features of the decade 1981–1991 for theories of design in Japan

This paper presents a summary of the theories of engineering design in Japan published in the period 1981–1991. There are many relevant features from the period in the development of engineering design theories in Japan. The most remarkable feature is the enthusiasm for the application of the Artificial Intelligence to the development of the so-called Intelligent CAD systems.     

Predictability of Gleason score and reduction time (tau) of prostatic volume after castration for the prognosis of prostatic cancer

BACKGROUND: After 3 years from the introduction of laparoscopic adrenalectomy in an endocrine surgery unit the results are retrospectively compared with those achieved by traditional techniques with the aim of comparing the respective advantages. METHODS: During this period 68 laparoscopic adrenalectomies have been performed. The main pre-, intra- e postoperative parameters of the adrenalectomies for benign neoplasm have been examined. Mean follow-up was 51 months (65.3 for open adrenalectomy and 18.8 for laparoscopic). RESULTS: Statistical studies were homogeneous between the two groups. The laparoscopic adrenalectomy--with the same effectiveness--thanks to less peritoneum and parietal stress, is followed by fewer postoperative complications, faster resumption of biological functions, earlier return to work and better cosmetic results. CONCLUSIONS: On the basis of our personal experience laparoscopic adrenalectomy is to be considered the treatment of choice in the majority of adrenal benign neoplasms.     

Gadolinium blocks the delayed rectifier potassium current in isolated guinea-pig ventricular myocytes

The effect of Gd3+ on the delayed rectifier potassium current (IK) in single guinea-pig ventricular myocytes was tested using whole-cell patch-clamp techniques. It was found that Gd3+ blocked 70% of the IK tail current at a concentration of 100 microM. The EC50 was 24 microM. Action potential durations were, however, reduced, consistent with a predominant effect on depolarizing L-type Ca2+ current (Ica.L). In the presence of 5 microM nifedipine Gd3+ prolonged the action potential. Using carbon fibres to stretch cells we observed that 10 microM Gd3+ was not effective in reducing a large stretch-activated increase in resting calcium. Modelling studies using the OXSOFT HEART program suggest that this lack of response is influenced by blockade of repolarizing current but is best reproduced by additional blockade of Ca2+ extrusion via the Na(+)-Ca2+ exchanger. When Gd3+ is used as a blocker of stretch-activated channels its actions upon both Ica.L and IK must therefore be accounted for.     

GFR alpha-4 and the tyrosine kinase Ret form a functional receptor complex for persephin

Glial-cell-line-derived neurotrophic factor (GDNF), neurturin and persephin are structurally related, secreted proteins that are widely expressed in the nervous system and other tissues and promote the survival of a variety of neurons during development. GDNF and neurturin signal through multicomponent receptors that consist of the Ret receptor tyrosine kinase and one of two structurally related glycosyl-phosphatidylinositol (GPI)-linked ligand-binding subunits: GFR alpha-1 is the preferred ligand-binding subunit for GDNF, and GFR alpha-2 is the preferred ligand-binding subunit for neurturin. Two additional members of the GFR alpha family of GPI-linked proteins have recently been cloned: GFR alpha-3 and GFR alpha-4. We have shown that persephin binds efficiently only to GFR alpha-4, and labelled persephin is effectively displaced from cells expressing GFR alpha-4 by persephin but not by GDNF or neurturin. Using microinjection to introduce expression plasmids into cultured neurons, we have also shown that coexpression of Ret with GFR alpha-4, confers a marked survival response to persephin but not to GDNF or neurturin. These results demonstrate that GFR alpha-4 is the ligand-binding subunit for persephin and that persephin, like GDNF and neurturin, also requires Ret for signalling.     

A method of evaluating the near diffracted field

A simple expression for the diffracted field by a slit or a flanged parallel-plate waveguide is derived from which we can readily evaluate the near field by applying the fast Fourier transform. Some numerical results are presented for the diffracted wave of an isotropic cylindrical wave by an infinitely long slit in a thin conducting screen.     

Thermal stability and behavior of platelet-shaped SBA-15 containing Zr

SBA-15 with a platelet shape, containing Zr(IV), (Zr-SBA-15) was prepared to characterize its thermal stability and thermal behavior in comparison with conventional, rod-shaped SBA-15. The small angle X-ray diffraction (SAXRD) lines of Zr-SBA-15 and SBA-15 disappeared at 1,373 and 1,273?K, respectively. The pore diameter of the Zr-SBA-15 was almost constant from 773 to 1,073?K and decreased above 1,173?K, whereas the SBA-15 pore diameter decreased with increasing calcination temperature from 773 to 1,173?K. Therefore, the thermal stability of the Zr-SBA-15 was higher than that of SBA-15. Zr(IV) distributed within the framework prevents the pores from shrinkage by heating, and the Zr(IV) forms a ZrO₂ crystalline phase above 1,273?K. When calcined at 1,873?K, the Zr-SBA-15 mesostructure collapsed while maintaining its hexagonal platelet shape. The collapse of the mesostructure at 1,373?K, caused the Zr-SBA-15 to shrink in the width direction by approximately 40% compared with that calcined at 773?K, although the dimension hardly changed in the thickness direction.