Effects of radial wall motion and flow waveform on the wall shear rate distribution in the divergent vascular graft

Among the hemodynamic factors influencing intimal hyperplasia in the anastomotic region of a vascular graft, wall shear rate is believed to be one of the most important. We would like to study the effects radial wall motion on the wall shear rate distribution in the end-to-end anastomosis model of an artery and a divergent graft. Rigid and elastic models are constructed and the wall shear rate distributions are measured along the anastomosis using photochromic flow visualization method for carotid and femoral flow waveform. The mean and peak of shear rate decrease along the divergent graft, and the decreases are more significant in the elastic model. The shear rate waves are decomposed using the Fourier transform in order to separate the effects of radial wall motion and geometry. The percentage reductions of mean wall shear rates compared to steady shear rates at mean flow are calculated, and additional 8% (carotid) and 22% (femoral) reductions are observed in the elastic models near the end of the divergent graft. Also radial wall motion decreases the amplitudes of higher harmonics of wall shear rates in the elastic models. Since radial wall motion may affect the flow field differently for different geometry, wall elasticity should be considered in studying arterial hemodynamics.     

The Minimum Weight Dominating Set Problem for Permutation Graphs Is in NC

In this paper, we show that the problem of finding a minimum weight dominating set in a permutation graph, where a positive weight is assigned to each vertex, is in NC by presenting an O(log n) parallel algorithm with polynomially many processors on the CRCW model.     

Die Beeinflussung der Kohlenstoff- und Sauerstoffaktivität im flüssigen Eisen durch Nickel und Silizium sowie durch Chrom und Silizium

Untersuchung der gemeinsamen Einflüsse von Nickel und Silizium sowie Chrom und Silizium auf die chemischen Aktivitäten von Kohlenstoff und Sauerstoff im flüssigen Eisen bei 1600°C unter Kohlenmonoxid-Kohlendioxid-Atmosfhäre. Zeichnerische Darstellung der Versuchsergebnisse. Vergleich mit Wirkungsparametern der Randsysteme.     

Soy protein ingredients prepared by new processes—Aqueous processing and industrial membrane isolation

The production of food ingredients from undefatted soybeans by aqueous processing and isolation of protein from soy flour by ultrafiltration membranes has been demonstrated adequately during the past decade. These relatively new techniques offer significant advantages over conventional soy processing methods. Aqueous processing requires no petroleum-based solvent and consequently provides increased safety and flexibility of operation (because start-up and shutdown are safe and easy). It also provides opportunities for removal or deactivation of undesirable constituents of raw materials with appropriate water-soluble chemicals. It is, however, less efficient in oil extraction, and demulsification is required to recover clear oil when emulsions form. Ultrafiltration processes recover protein directly from soy flour extracts and thereby avoid generation of the whey which results from the conventional isoelectric precipitation. These processes have the advantages of increased isolate yield (as whey proteins are recovered in the isolate), and produce products having enhanced functionality and nitrogen solubility. The two processing techniques have subsequently been combined to obtain a single procedure with the advantages of each. Extracts from undefatted soybeans have been membrane processed with and without separating the oil to produce a variety of new soy protein ingredients.     

Asymptotic solution to moving-bed exchange equations

Asymptotic solutions to countercurrent moving-bed exchange equations are discussed considering the effect of axial dispersion and interphase mass transfer. Existence conditions are derived by using perturbation theory in a properly defined moving coordinate system. The flow are ratio turns out to be a very important parameter and its effect on the exchange performance is carefully examined. In particular, the effect of interphase mass transfer disappears when the exchange zone becomes stationary. Applications are illustrated by using the Langmuir adsorption isotherm. Numerical solutions of the transient equations show that the asymptotic solution may be useful.     

Physicochemical characterization of diclofenac sodium-loaded poloxamer gel as a rectal delivery system with fast absorption

Rectal poloxamer gel systems composed of poloxamers and bioadhesive polymers were easy to administer to the anus and were mucoadhesive to the rectal tissues without leakage after the dose. However, a poloxamer gel containing diclofenac sodium could not be developed using bioadhesive polymers, since the drug was precipitated in this preparation. To develop a poloxamer gel using sodium chloride instead of bioadhesive polymers, the physicochemical properties such as gelation temperature, gel strength, and bioadhesive force of various formulations composed of diclofenac sodium, poloxamers, and sodium chloride were investigated. Furthermore, the pharmacokinetic study of diclofenac sodium delivered by the poloxamer gel was performed. Diclofenac sodium significantly increased the gelation temperature and weakened the gel strength and bioadhesive force, while sodium chloride did the opposite. The poloxamer gels with less than 1.0% sodium chloride, in which the drug was not precipitated, were inserted into the rectum without difficulty and leakage, and were retained in the rectum of rats for at least 6 hr. Furthermore, poloxamer gel gave significantly higher initial plasma concentrations and faster T_max of diclofenac sodium than did solid suppository, indicating that drug from poloxamer gel could be absorbed faster than that from the solid one in rats. Our results suggested that a rectal poloxamer gel system with sodium chloride and poloxamers was a more physically stable, convenient, and effective rectal dosage form for diclofenac sodium.     

Spatial and Temporal Resolution of Conjugate Conduction-Convection Thermal Resistance

A transient, 3-D solution to the heat conduction equation with a small square heat source on an adiabatic surface and Newtonian convection on the opposite side was obtained using Green's functions. The geometry conservatively models conduction spreading resistance encountered by small, concentrated heat sources such as light-emitting diodes and integrated circuits in general, mounted to larger substrates such as the base of a heat sink experiencing Newtonian convection. The solution is presented for a range of nondimensional parameters. Superposition techniques can also be used to extend the applicability of the current solution to the temperature prediction of arbitrary heat flux patterns in certain cases. This technique only holds for applications where the heat transfer coefficient is not a function of temperature, such as thermal management strategies designed to rely on forced convection with air.     

Multiuser adaptive transmission technique for time-varying frequency-selective fading channels

This paper proposes an efficient multiuser adaptive modulation and coding (AMC) scheme that considers inevitable feedback delay by employing short-term and long-term channel state information (CSI) in time-varying frequency-selective fading channels. By taking the statistic of the true signal-to-noise ratio (SNR) at a given predicted SNR value into account, the required transmit power to meet the target packet-error-rate (PER) can be obtained and used for user selection, power allocation, and modulation and coding set (MCS) selection. In addition, a simple and useful approximation method of obtaining the required transmit power is proposed. The performance of the proposed scheme is shown to be much better than that of conventional schemes without considering the feedback delay or the prediction error. The proposed scheme can also reduce the feedback resource while maintaining the system throughput by allocating different feedback resources to different users according to their prediction error variances.     

Formulation of nondairy coffee whiteners with cottonseed protein isolates

Nondairy coffee whiteners were prepared on a pilot scale using four different glandless cottonseed protein isolates prepared by different processes. Bulk density, whitening capacity, cream separation and oil retention capacity of the whiteners were compared to those formulated with sodium caseinate and a commercial whitener. Glandless cottonseed protein isolates, prepared by conventional and aqueous extraction processes, are poor ingredients for coffee whitener production, showing poor whitening capacity, separation of proteins through sedimentation and separation of fat as a cream layer in a mixture with aqueous coffee. Succinylated cottonseed proteins showed many markedly improved characteristics as coffee whiteners. Ca. 50% replacement of sodium caseinate with succinylated cottonseed protein isolate did not affect the quality of whiteners compared to that of 100% sodium caseinate-based whitener.     

Transmission of Traffic Information Using a Terrestrial Digital Multimedia Broadcasting System

This letter introduces an efficient transmission of traffic information through a terrestrial digital multimedia broadcasting system, which is a multimedia and mobility empowered option of the European digital audio broadcasting system. By adapting Korean characteristic traffic information into the transport protocol expert group messages in the traffic information delivery, a highly efficient traffic information system was implemented and tested in Korea.