Data Storage Unit Research Articles

Regional variations in nocturnal fluctuations in subcutaneous blood flow rate in the lower leg of man

The purpose of the study was to investigate possible regional variations in recently discovered nocturnal fluctuations in subcutaneous blood flow rates. Approximately 90 min after going to sleep, a 100% blood flow rate increment, lasting about 100 min, has been demonstrated in the distal and medial aspect of the right lower leg of normal human subjects. In the present study subcutaneous adipose tissue blood flow rates were measured simultaneously in the right and left lower legs of 16 normal human subjects over 12-20 h ambulatory conditions. The 133Xe wash-out technique, portable CdTe(Cl) detectors and a portable data storage unit were used. The tracer depots were applied on the medial aspects of the right lower leg and on the medial (series 1) and lateral (series 2) aspect of the left lower leg 10 cm proximal to the malleolar level by means of the epicutaneous, atraumatic labelling technique. A nocturnal hyperaemic response was demonstrated at both the medial and lateral aspect of the leg. As for the degree of hyperaemia and the absolute blood flow rates in the different phases, there were some deviations between the medial and the lateral locations. However, a highly significant positive correlation was observed in both series concerning the duration of the period from going to bed until the hyperaemia phase (P less than 0.001). The mechanisms involved in the nightly subcutaneous hyperaemia are at present unknown. The sudden, synchronized increase in nocturnal subcutaneous blood flow points to a central nervous or humoral elicitation, although local metabolic factors might participate as well.

Nocturnal variations in peripheral blood flow, systemic blood pressure, and heart rate in humans

Subcutaneous adipose tissue blood flow rate, together with systemic arterial blood pressure and heart rate under ambulatory conditions, was measured in the lower legs of 15 normal human subjects for 12-20 h. The 133Xe-washout technique, portable CdTe(Cl) detectors, and a portable data storage unit were used for measurement of blood flow rates. An automatic portable blood pressure recorder and processor unit was used for measurement of systolic blood pressure, diastolic blood pressure, and heart rate every 15 min. The change from upright to supine position at the beginning of the night period was associated with a 30-40% increase in blood flow rate and a highly significant decrease in mean arterial blood pressure and heart rate (P less than 0.001 for all). Approximately 100 min after the subjects went to sleep an additional blood flow rate increment (mean 56%) and a simultaneous significant decrease in mean arterial blood pressure (P less than 0.001) were observed. The duration of this hyperemic phase was 116 min. A highly significant reduction of the subcutaneous vascular resistance (50%) was demonstrated during the hyperemic blood flow rate phase compared with the surrounding phases (P less than 0.0001). The synchronism of the nocturnal subcutaneous hyperemia and the decrease in systemic mean arterial blood pressure point to a common, possibly central nervous or humoral, eliciting mechanism.

Lower leg subcutaneous blood flow during walking and passive dependency in chronic venous insufficiency

The blood flow in the subcutaneous adipose tissue of the lower leg of eight normal subjects and 19 patients with chronic venous insufficiency was measured. The 133Xe-washout technique was used with portable CdT1(C1) detectors and a data storage unit. Only those patients with ulcers and a systolic blood pressure at the toe of greater than or equal to 60 mm were investigated. In the controls the relative blood flow during sitting was 0.61 (range 0.35-0.80). In the patients it was 0.46 (range 0.22-0.87). This difference was not significant. During walking the blood flow increased in controls as well as in the patients compared to the value determined in the sitting position (P = 0.0078 and P = 0.0028, respectively, Wilcoxon matched-pairs test). The relative blood-flow rate during walking was 0.96 (range 0.60-1.58) in the controls, and 1.04 (range 0.49-1.46) in the patients. The difference between the normal subjects and the patients was not significant (P = 0.79). We conclude from our studies that patients with venous insufficiency are able to increase their blood flow during walking to the same extent as normal controls.

Nocturnal variations in subcutaneous blood flow rate in lower leg of normal human subjects

Subcutaneous adipose tissue blood flow rate was measured in the lower leg of 22 normal human subjects over 12- to 20-h ambulatory conditions. The 133Xe washout technique, portable CdTe(Cl) detectors, and a portable data storage unit were used. The tracer depot was applied on the medial aspect of the right lower leg 10 cm proximal to the malleolar level by means of the epicutaneous, atraumatic labeling technique. The change from upright to supine position from day 1 in the beginning of the night period elicited an instantaneous blood flow rate increment of 30-40% in accordance with a decrease in central and local postural sympathetic vasoconstrictor activity. During sleep, characteristic variations in subcutaneous blood flow were disclosed. The 133Xe washout curve could be divided into three segments with significantly different slopes. Approximately 90 min after the subject went to sleep, an additional blood flow rate increment of considerable magnitude was observed. The mean increase was 84%, but in several cases a greater than 200% increment was measured (maximum 244%). The intra-individual coefficient of variation for the nocturnal blood flow response was in triplicate measurements 25% (n = 9). The hyperemic phase lasted approximately 100 min after which the blood flow rate returned to the level measured at the beginning of the night period. The blood flow rates measured on the second day did not differ from those on the first day. Control measurements performed under similar thermal conditions, but with the subjects kept awake, did not reveal any hyperemic phases. This points toward changes in cardiovascular regulatory mechanisms during sleep.(ABSTRACT TRUNCATED AT 250 WORDS)

Laser-based pavement condition monitoring system.

A laser-based pavement condition monitoring system (PCMS) provides the longitudinal roughness, transverse deformation, and surface distress ofaroad simultaneously. The longitudinal roughness is detected by three displacement sensors based on laser trigonometry. The transverse deformation is measured by a structured light method utilizing a planar light pattern.The surface distress is recorded by a slit-camera. Data acquisition instruments as well as data processing and storage units are installed on a vehicle and the measurement is performed in thenormal traffic flow (up to 100km/h).

DATデータストレージを用いた地震波形連続収録システム

DATデータストレージを用いた地震波形連続収録システム

Special Polymers for Data Memories

Microelectronics represent to a large extent the key industry in the 80′ and 90′s of this century. Progress in microelectronics, however, is directly related to progress in data storage technology. Up to now main data memories are exclusively based on silicon semiconductor devices, mass data memories—at least the most important ones—are magnetic data storage units. New on the market are non-erasable optical memories using polymers or polymer substrates (e.g., CD-ROM’s). Under development are erasable optical and electrical polymer data memories: photopolymers, LC-side chain polymers, ferroelectric polymers, and such for holographic or photo-chemical hole burning data storage. The paper describes the current state of art and compares the various developments of special polymers in an attempt to forecast the possible significance of polymer memories with high data packing densities in relation to the established technologies.

Direct in vivo study of flowing blood-artificial surface interactions — An original application of dynamic isotopic techniques

A Ge(Li) detector, associated with a data acquisition and storage unit, and a data analysis facility, is used to record sequentially the activity, related to several radioisotopes, inside an extracorpeal shunt, settled between the femoral artery and the colateral vien of an anaesthetized dog. The shunt is made of a material, the haemocompatibility of which needs to be evaluated. Before the blood is allowed to flow through the shunt, the circulation of the dog is fed with technetium- or indium-labelled biological species thought to be concerned with blood-artificial surfaces interactions. The method described here offers the possibility to compute kinetics parameters for these interactions.

Data processing/storage unit suitable for all NC/CNC machine tools

A CNC data processing and storage unit suitable for all NC and CNC machine tools is now available from TI Rockwell Limited, Welsh Harp, London.

Magnetic recording for computers

Peripheral data-storage units based on magnetic recording play a major role in computer systems. They have access times ranging from tens of milliseconds to seconds, contrasting with the microsecond or submicrosecond performance of core or semiconductor main-frame stores, but provide an online storage capacity of millions of characters at costs of ‘millipence’ per bit. The major components are the magnetic-recording or storage medium, the recording head, the transport mechanism and the electronics. The transport mechanism moves the heads and medium accurately with respect to each other; the control electronics control the mechanism in response to computer command; and the data-channel electronics, acting through the recording heads, write and read data to and from the storage medium. In the paper, the functions and general performance parameters of these units are reviewed, and the basic magnetic-recording principles are explained, with emphasis on the design of the recording medium and heads. Exchangeable-disc stores and magnetic-tape transports are then described in some detail, and attention is drawn to the level of development in many closely related branches of engineering that makes the present overall performance possible. Other magnetic peripheral stores such as drum and magnetic-card files are briefly reviewed, and the paper concludes by considering the limits of this technology and briefly discussing possible future technologies in this area.