Simple neurobehavioral functional observational battery and objective gait analysis validation by the use of acrylamide and methanol with a built-in recovery period

To test the influence of perfusion pressures on structural preservation of human placental villi and on the dilatation of the so-called transtrophoblastic channels, cotyledons of 32 term human placentas have been perfused in vitro. Periods of perfusion with isotonic Ringer solution under various arterial and venous hydrostatic pressures were followed by perfusion fixation. In some experiments, lanthanum hydroxide as an extracellular marker was added to the fixative. Distention of the fetal vascular system, stromal edema and continuity, as well as trophoblastic vacuolization were studied via electron microscopy with subsequent morphometry. The findings suggest that arterial hydrostatic pressures in the perfusion system of about 80 cm H2O are needed to guarantee homogeneous perfusion of the fetal vascular system. To avoid stromal edema and trophoblastic vacuolization, venous hydrostatic pressures of 4 cm H2O and arterial hydrostatic pressures of 80 cm H2O should not be exceeded. It is concluded that the trophoblastic vacuoles are dilated segments of the so-called transtrophoblastic channels. The functional importance of in vivo variations of fetal intravascular hydrostatic pressure for the dilatation of transtrophoblastic channels and for fetal water balance is discussed.     

New model explaining the softening-to-hardening transition due to hydrogen in iron and steel

A theoretically developed model based on experimental data, explaining the softening and hardening mechanisms of iron as a result of hydrogen introduction.     

Synthesis of antimicrobial heteroaryl-substituted-1,2,3-triazolines via the reaction of diazomethane with anils and mixed azines of thiophenealdehyde and/or isatin

Diazomethane was reacted with nitro-substituted anils of thiophenealdehyde and/or isatin and with some unsymmetric azines. 1,2,3-Triazolines were obtained in all cases. Product constitution is discussed. Some of these were found to inhibit the development of a range of Gram-positive and Gram-negative bacteria.     

Le cobaltite de strontium Sr2Co2O5 : Caracterisation et proprietes magnetiques

Stoichiometric strontium cobaltite oxide Sr₂Co₂O₅ has been prepared at 910°C in air and characterized by chemical analysis and X-ray diffraction. Temperature dependent magnetic measurements have shown a magnetic transition which is confirmed by DTA and related to a structural modification. At high temperature a brownmillerite-type structure is stabilized by the high spin state of the trivalent cobalt (four free electrons). On the other hand, the magnetic behaviour of the low temperature phase which derives from the 2H-perovskite type may be explained by the simultaneous presence of an intermediary spin state (two free electrons) and a low spin state (no free electron) of trivalent cobalt. These electronic transitions are discussed in connection with the cobalt environment.     

A parallel algorithm for random walk construction with applicationto the Monte Carlo solution of partial differential equations

Random walks are widely applicable in statistical and scientific computations. In particular, they are used in the Monte Carlo method to solve elliptic and parabolic partial differential equations (PDEs). This method holds several advantages over other methods for PDEs as it solves problems with irregular boundaries and/or discontinuities, gives solutions at individual points, and exhibits great parallelism. However, the generation of each random walk in the Monte Carlo method has been done sequentially because each point in the walk is derived from the preceding point by moving one grid step along a randomly selected direction. A parallel algorithm for random walk generation in regular as well as irregular regions is presented. The algorithm is based on parallel prefix computations. The communication structure of the algorithm is shown to ideally fit on a hypercube of n nodes, where n is the number of processors     

A simple detector for trellis-coded PSK mobile radio systems

A simple detector for a trellis-coded PSK mobile radio system is proposed. A precoder is added to the regular TC-PSK modulator before convolution coding, and a simple one-bit differential detector is used in the receiver. The decision is made symbol by symbol based on the output samples. The bit error rate of this system is evaluated in fast Rayleigh fading characterizing mobile radio channels by numerical integration.     

Polymeric surfactants for enhanced oil recovery. Part V: Prediction models for the effect of temperature and length of polyoxyethylene chain or hlb on surface and thermodynamic properties of some ethoxylated polymeric nonionics

Several equation models were investigated to find the relationship between temperature (T). number of ethylene oxide (EO) units (n) or the hydrophile-lipophile balance (HLB) and the surface and thermodynamic properties of some ethoxylated alkylphenol-formaldehyde polymeric nonionic surfactants. These properties include critical micelle concentration (CMC), free energy of micellization (ΔG_mic), surface tension at CMC (7_CMC), effectiveness (γ_CMC) and efficiency (pC₂₀) of surfactant to reduce the surface tension of water. The values of the ratio CMC/C_{2(π = 20)} were also considered. The linear multiple regression technique was employed to determine the parameters of the equations and to choose the best forms with the highest values of R² and F-ratio which reflect the goodness and the reliability of the fit.     

Experimental determination of axial dispersion coefficient in a bubble column

A new graphical method of finding axial dispersion coefficients in a bubble column is developed. This method requires only the area above an experimental curve, thus is simpler than the conventional method of curve fitting. The new method is used to find the dimensionless dispersion number in the bubble column and shows that the dispersion number decreases with column Reynolds number due to increasing coalescence of bubbles at higher gas flow-rates.