A method of constructing an SDH‐based time transfer network and its experimental examination

In this paper we propose a simplified SDH (Synchronous Digital Hierarchy)‐based time synchronous system that does not require the modification of existing SDH transmission equipment (STE) and clock supply equipment (CSE). The system has auxiliary time synchronizing equipment (TSE) attached to existing STE and CSE and can be expanded in a cascade and branch manner, where frequency and time are separately synchronized, and which enables us to partially time‐synchronize an SDH network or to introduce a time transfer network locally. Experimental time synchronizing devices using a 576‐kbps data communication channel (DCC) in the section overhead (SOH) showed potentially satisfactory performance, with synchronization errors of a four‐link system on the order of submicroseconds. Noise analyses of experimental TSE, DCC, CSE, and optical links showed that accuracy on the order of microseconds can be achieved. © 2000 Scripta Technica, Electr Eng Jpn, 132(2): 39–48, 2000     

Inhibition of growth and p21ras methylation in vascular endothelial cells by homocysteine but not cysteine

Although hyperhomocysteinemia has been recognized recently as a prevalent risk factor for myocardial infarction and stroke, the mechanisms by which it accelerates arteriosclerosis have not been elucidated, mostly because the biological effects of homocysteine can only be demonstrated at very high concentrations and can be mimicked by cysteine, which indicates a lack of specificity. We found that 10-50 microM of homocysteine (a range that overlaps levels observed clinically) but not cysteine inhibited DNA synthesis in vascular endothelial cells (VEC) and arrested their growth at the G1 phase of the cell cycle. Homocysteine in this same range had no effect on the growth of vascular smooth muscle cells (VSMC) or fibroblasts. Homocysteine decreased carboxyl methylation of p21(ras) (a G1 regulator whose activity is regulated by prenylation and methylation in addition to GTP-GDP exchange) by 50% in VEC but not VSMC, a difference that may be explained by the ability of homocysteine to dramatically increase levels of S-adenosylhomocysteine, a potent inhibitor of methyltransferase, in VEC but not VSMC. Moreover, homocysteine-induced hypomethylation in VEC was associated with a 66% reduction in membrane-associated p21(ras) and a 67% reduction in extracellular signal-regulated kinase 1/2, which is a member of the mitogen-activated protein (MAP) kinase family. Because the MAP kinases have been implicated in cell growth, the p21(ras)-MAP kinase pathway may represent one of the mechanisms that mediates homocysteine's effect on VEC growth. VEC damage is a hallmark of arteriosclerosis. Homocysteine-induced inhibition of VEC growth may play an important role in this disease process.     

Physiological significance of plasma sulfoconjugated dopamine in patients with hypertension--clinical and experimental studies

Sulfoconjugated catecholamines, especially dopamine sulfate, have recently attracted much attention because of the possibility of their conversion to active free dopamine by tissue arylsulfatase. In the present study, we have measured the plasma levels of free and sulfoconjugated dopamine in patients with hypertension and have investigated the physiological significance of sulfoconjugation. Results showed that the plasma level of dopamine sulfate in patients with essential hypertension was higher than the level in control subjects, and was highest in patients with renal hypertension. However, the plasma level of free dopamine showed no significant difference between patients with hypertension and normal subjects. Moreover, after normalization of blood pressure in hypertensive patients with medication, the plasma levels of conjugated dopamine decreased to almost the control value. In the experimental study, dopamine sulfate inhibited angiotensin II-induced aldosterone release from bovine adrenal cortical cells to a similar extent as produced by free dopamine. From these results, we have concluded that plasma sulfoconjugated dopamine may regulate free dopamine in the plasma of patients with hypertension, and it may have some physiological effects on blood pressure regulation.     

Histologic features of the leukemia in children (author''s transl)

Semistatic air volume-pressure (V-P) loops were recorded from 172 isolated lungs obtained from infants and children at necropsy. Technically unsatisfactory V-P loop behaviour and the presence of pathological changes led to the exclusion of 98 lungs. A further 10 lungs were excluded as it was decided to study the period of growth up to 90 cm crown-heel length. A total of 64 left lungs remained which were designated "normal". Control data were collected in an attempt to quantify the effects of storage and variations in inflation technique. A maximum inflation pressure of +30 cmH2O was used as a standard Pmax. The resulting maximum inflation volume (Vmax) data showed a cubic relation to the crown-heel length which deviated from the values obtained by the use of in-vivo regression equations. The extent and pattern of the deviation suggest that the technical factors are not a major contributory cause, and other explanations are discussed. The low-pressure proportional data from the deflation limb of the V-P curve are plotted against the crown-hell length, and the resulting curve is analysed. There is a sharp fall in the proportion of Vmax retained in the lung at +5 cmH2O and +2-5 cmH2O with increasing body length, but proportional volume at zero transpulmonary pressure follows the same growth-related pattern as Vmax.     

A CMOS ultra-wideband impulse radio transceiver for 1-mb/s data communications and /spl plusmn/2.5-cm range finding

A CMOS ultra-wideband impulse radio (UWB-IR) transceiver was developed in 0.18-/spl mu/m CMOS technology. It can be used for 1-Mb/s data communications as well as for precise range finding within an error of /spl plusmn/2.5 cm. The power consumptions of the transmitter and receiver for data communication are 0.7 and 4.0 mW, respectively. When an LNA operates intermittently through bias switching, the power consumption of the transceiver is only 1 mW. The range for data communication is 1 m with BER of 10/sup -3/. For ranging applications, the transmitter can reduce the power to 0.7 /spl mu/W for 1k pulses per second, and the receiver consumes little power. The transceiver design, all-digital transmitter, and intermittent circuit operation at the receiver reduce the power consumption dramatically, which makes the transceiver well suited for applications like sensor networks. The electronic field intensity is lower than 35 /spl mu/V/m, and thus the UWB system can be operated even under the current Japan radio regulations.     

High-response flux control of direct-field-oriented induction motorwith high efficiency taking core loss into account

Stator core loss has significant adverse effects when an induction motor is controlled by the conventional field-oriented method. Therefore, taking core loss into account should make it possible to control the torque very precisely. In this paper, a direct-field-oriented induction motor with a deadbeat rotor flux controller was developed. The method ensures maximum efficiency in the steady state without degradation of the dynamic response. Simulation and experimental results have demonstrated that this method has higher efficiency and good speed response without any degradation in the transient characteristics     

Automatic selective equaliser for telephone facsimile transmission

A simple automatic equaliser designed especially for G2 as well as G1 facsimile signals received through carrier links is presented. The new method requires no additional signal, utilising only a phasing signal to fix the equalising parameters by detecting the symmetry in the received step response.     

Isolation of Multipotent Nestin-Expressing Stem Cells Derived from the Epidermis of Elderly Humans and TAT-VHL Peptide-Mediated Neuronal Differentiation of These Cells

A specialized population of cells residing in the hair follicle is quiescent but shows pluripotency for differentiating into epithelial-mesenchymal lineage cells. Therefore, such cells are hoped to be useful as implantable donor cells for regenerative therapy. Recently, it was reported that intracellular delivery of TAT-VHL peptide induces neuronal differentiation of skin-derived precursors. In the present study, we successfully isolated multipotent stem cells derived from the epidermis of elderly humans, characterized these cells as being capable of sphere formation and strong expression of nestin, fibronectin, and CD34 but not of keratin 15, and identified the niche of these cells as being the outer root sheath of the hair follicles. In addition, we showed that TAT-VHL peptide induced their neuronal differentiation in vitro, and confirmed by fluorescence immunohistochemistry the neuronal differentiation of such peptide-treated cells implanted into rodent brains. These multipotent nestin-expressing stem cells derived from human epidermis are easily accessible and should be useful as donor cells for neuronal regenerative cell therapy.