Shape memory properties of polypeptide hydrogels having hydrophobic alkyl side chains

Polypeptide hydrogels were prepared by cross-linking of hydrophobically-modified poly[N⁵-(2-hydroxyethyl) l-glutamine] having alkyl side chains –C_nH_2n+1. Chain length of the alkyl group was n = 8, 16, and 18, and their mole fractions in the polypeptide were varied in the range of 0.05–0.16. Shape memory ability of the prepared polypeptide hydrogels was investigated. After deformation at 60 °C, the hydrogel was cooled in order to fix the temporary deformed shape. It was found that crystallization of the alkyl side chains did not occur, and the fixation ability of the hydrogel at 0 °C was low. In the subsequent heating process, the deformed temporary shape spontaneously recovered to the original shape gradually with increasing temperature, in other words, the shape recovery ratio varied with depending on the recovery temperature. From these observations, it was proposed that the shape fixation of the polypeptide hydrogel was achieved by strong segregation of the hydrophobic alkyl chains at low temperature, and the shape recovery of the deformed hydrogel was accompanied by the gradual decrease of the segregation strength with the temperature increase.     

Wave venation in downward gas-liquid two-phase flow (part I,time-spatial behavior chart of interface and analysis of main wave-vein)

Time-series information on both the cross-sectional mean liquid holdup along a tube axis and the gas-liquid phase distribution along a tube diameter was obtained by means of supermultiple cross-sectional mean liquid holdup probes (S-CHOP) and semi-supermultiple point-electrode probes (SS-PEP) for vertical downward gas-liquid two-phase flow. Typical time-spatial behavior charts of interface and gas-liquid interfacial profiles are presented. Close inspection of these results reveals that a huge wave and a disturbance wave appear in downward two-phase flow as well as upward flow. It was clarified that the huge wave flow region covers a wide range of superficial gas velocities. Wave velocity, wave width and maximum liquid holdup of individual waves were examined by wave-vein analysis. Histograms of these flow parameters were also studied. It was found that there exist distinct differences in wave width between the huge wave and the disturbance wave. © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25(8): 499–510, 1996     

Characteristics of interfacial profiles in upward and downward gas-liquid two-phase plug flow

Gas-liquid interfacial profiles in plug flow for both upward and downward flows were obtained using semi-supermultiple point-electrode probes, comprising 67 sensing tips arranged on a tube diameter. Typical interfacial profiles are demonstrated for both flows. Close inspection of the profiles reveals that four zones exist in a pair of gas and liquid slugs for upward plug flow and a high slip velocity region in downward plug flow. The lengths of the swelling liquid front zone and the wake zone were determined. The length of the wake zone strongly depends on the relative velocity between the liquid film around the gas slug and the liquid phase in the liquid slug. Characteristic distributions of bubbles within liquid slugs were found, i.e., three types of radial distributions of void fraction, namely saddle-shaped, trapezoidal and bullet-shaped distributions, exist for upward flow. The two types for downward flow exclude the saddle-shaped distribution. © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25 (8): 568–579, 1996     

An autopsy case of intracranial hemorrhage during tissue plasminogen activator infusion

A comprehensive classification system has been proposed by the AO/ASIF Foundation for the classification of long bone fractures. After an explanatory talk and with the aid of an illustrated pamphlet, 18 orthopaedic surgeons were asked to classify 10 long bone fractures according to the AO system. Three of the participating surgeons had previous experience of the classification system. After individual classification, a consensus classification was derived and the results of the individual and consensus codings were compared. Only 32 per cent of all codings agreed with the final consensus. There was no difference between the surgeons with previous experience of the system (66 per cent) and novice coders (69 per cent) in the number of inaccurate codes when compared with the consensus codes. Reasons for error in coding are discussed. It is recommended that if the AO system is used for the purposes of research and computer-based audit, a consensus of opinion is used as the basis of classification.     

Study on behavior of ephemeral wave in gas‐liquid two‐phase flow: Part 2. Characteristics in flow parameter of ephemeral waves

In order to clarify the behavior of ephemeral waves, flow parameters of ephemeral waves, such as the number and residence zone lengths per unit axial length, mean values and standard deviations of wave velocity, width, and maximum holdup, were determined using a wave‐vein analysis in upward huge wave flow and annular flow. The mean values of wave velocities, widths, and maximum holdups of ephemeral waves are compared with those of liquid lumps having main wave‐veins, and the differences in the parameters between those liquid lumps are discussed. Furthermore, the parameters of both active ephemeral waves and inactive ephemeral waves are determined, and the characteristics in the flow parameters of two types of ephemeral waves are presented. © 1999 Scripta Technica, Heat Trans Asian Res, 29(1): 1–14, 2000     

Effect of pressure on entrainment flow rate in vertical upwards gas—liquid annular two-phase flow. Part I: Experimental results for system pressures from 0.3 MPa to 20 MPa

The purpose of this study is to investigate the pressure effects on the entrainment flow rates in vertical gas—liquid annular two-phase flow. The cross-sectional entrainment flow rates were measured using an isokinetic probe method. It was found that the behavior of cross-sectional entrainment flow rate profiles is divided into low- and high-pressure regions. Also, the entrainment flow rates amount to 90 percent of the total liquid flow rate under high-pressure conditions. In this study, system pressure in the closed-loop system was changed substantially from 0.3 MPa to 20 MPa at a constant fluid temperature in vertical upward flow. © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25(5): 267–280, 1996     

Study of the behavior of ephemeral waves in gas–liquid two‐phase flow: I. Determination of sub‐wave‐veins

Time‐spatial measurements of liquid holdup distributions along the axis of a tube were carried out over the length of 1325 mm in upward gas–liquid two‐phase flow. In order to clarify the characteristics of the behavior of ephemeral waves, a method of determining sub‐wave‐veins, that is, the traces of ephemeral waves on the time‐spatial behavior charts of the interface, was developed. This method was applied to the flow conditions in huge wave flow and annular flow regimes, and the sub‐wave‐veins in these flow regimes were successfully determined. Time‐spatial behavior charts of the interface with determined sub‐wave‐veins were systematically presented and the characteristics of sub‐wave‐veins were discussed. Close inspection of the behavior of sub‐wave‐veins reveals that there are two types of ephemeral waves: one has a shorter life span and the other has a longer life span during which absorption and discharge of small ephemeral waves occurs. © 2001 Scripta Technica, Heat Trans Asian Res, 30(2): 114–125, 2001     

Wave venation in downward gas-liquid two-phase flow (part II,cluster analysis for huge waves and disturbance waves and characteristics of those waves)

Wave velocities and wave widths were determined using wave-vein analysis for a wide range of air and water flow rates. Cluster analysis by a K-mean algorithm was applied to the discrimination between huge and disturbance waves for the present experimental conditions. Individual waves discriminated by cluster analysis reasonably correspond to those recognized from the relation between wave velocity and wave width. Appearance flow conditions for liquid slug, huge and disturbance waves were clarified. The characteristics of wave velocity, wave width, and maximum liquid holdup for huge and disturbance waves are discussed. Comparison between liquid slug, huge wave and disturbance wave flow parameters reveals that there exist distinct differences in wave width of these waves. © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25 (8): 511–521, 1996