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Image fusion is used to combine multiple images of the same scene into a comprehensive representation. However, an image fusion method does not suit all fusion requirements in practice. In this paper, we introduce an image fusion framework based on wavelet transform, which is designed to satisfy the fusion applications as much as possible. The input images are firstly decomposed into wavelet domain. While analyzing the different frequency coefficients, the principles of fusion are discussed and adaptively assigned according to the properties of subimages. Finally, the fused image can be reconstructed via wavelet inverse transform. The experimental results show that our framework can preserve most features of original images, and the algorithm has some resistance to noise.

Broad-leaved plants are generally resistant to aryloxyphenoxypropionate (AOPP) and cyclohexanedione (CHD) herbicides. In laboratory experiments, however, we confirmed that Acanthospermum hispidum, a Compositae weed, was susceptible to one of the AOPP herbicides, fluazifop-butyl, but tolerant to other AOPP herbicides (quizalofop-ethyl and fenoxaprop-ethyl) and a CHD herbicide (sethoxydim). The symptoms induced by fluazifop-butyl in A. hispidum (wilting and necrosis) were distinctly different from those induced in oat (chlorosis). The period required to cause seedling death of A. hispidum (48-72 h) was shorter than that of oat (ca 15 days). The (R)-enantiomer of fluazifop-butyl was more active on this weed. In oat, lipid biosynthesis and acetyl-CoA carboxylase (ACCase) activity were inhibited, and electrolyte leakage from the shoots was increased by fluazifop-butyl and sethoxydim. In the case of A. hispidum, the membrane permeability increased and the lipid biosynthesis was inhibited only by fluazifop-butyl. These results indicate that A. hispidum is particularly sensitive to fluazifop-butyl, and its mechanism of action in the plant may be different from its mechanism of action in oat.

Steady and unsteady numerical simulations of two-dimensional flow in a collapsible channel were carried out to study the flow limitation which typically occurs when the upstream transmural pressure is held constant while flow rate and pressure gradient along the collapsible channel can vary independently. Multiple steady solutions are found for a range of upstream transmural pressures and Reynolds number using an arclength control method. The stability of these steady solutions is tested in order to check the correlation between flow limitation and self-excited oscillations (the latter being a consequence of unstable steady solutions). Both stable and unstable solutions are found when flow is limited. Self-excited oscillations and divergence instabilities are observed in certain solution branches. The instability of the steady solutions seems to depend on the unsteady boundary conditions used, i.e. on which parameters are allowed to vary. However, steady solutions associated with the solution branch before flow limitation where the membrane wall bulges are found to be stable for each of the three different boundary conditions employed. We conclude that there is no one to one correlation between the two phenomena in this two dimensional channel model.

We have studied steady flow in a 2-D channel with one plane rigid wall and with a segment of the other wall replaced by an elastic membrane. Numerical solutions of the full governing equations have been obtained for Reynolds number Re = 1-600. The numerical method was to solve the Navier-Stokes equations for given membrane shape by using the finite element scheme FIDAP, and use the membrane equation to iterate for the membrane shape. The control parameters are the downstream transmural pressure, P_d, the longitudinal tension, T, and the Reynolds Number, Re. For a given Re and P_d, where P_d = P _external-P_internal>0, there exists a limit of T, say T_c, below which no converged solution was found. There is a somewhat higher value, T_b, such that for T_c<T<T_b, the membrane bulges out at its upstream end while the downstream part still remains collapsed. It is extremely difficult, however, to obtain converged solutions with our numerical scheme as we decrease the tension to T_b and below. To investigate whether the breakdown of the solution could be of physical origin, we analysed a simple 1-D model of the same flow, similar to that of Jensen & Pedley (1989). The results confirms that, for given Re and P_d, there is a value of T (T_b), below which the upstream part of the membrane bulges out, with collapse only in the downstream part. Similarly, for fixed T, there is a value of Re (Re_b) above which no fully collapsed solutions are attainable. The values of T_b at given Re and P_d agree very well with the numerical results, especially for higher Re. Further, a qualitative comparison of our analytical predictions with the experimental measurements in a collapsible tube by Bonis & Ribreau (1978), show that it is near the bulging points that steady flow gave way to self-excited oscillations. Copyright 1995, 1999 Academic Press

The fibrinogen receptor on human platelets is a prototypic member of the integrin family and is composed of subunit glycoproteins IIb (gpIIb) and IIIa (gpIIIa) in a 1:1 stoichiometric ratio. We have isolated cDNA clones for gpIIb and gpIIIa and localized both genes to chromosome 17. In the current study, several approaches were used to localize and map the genes for gpIIb and gpIIIa. A preliminary evaluation of subchromosomal localization was performed by using a panel of mouse-human somatic cell hybrids that contain different amounts of the long arm of human chromosome 17. Southern hybridization to the DNA of these hybrids shows that both genes map near the thymidine kinase gene. In situ hybridization to intact human chromosomes localized both genes to the 17q21-22 region. To better define the physical distance between the two genes, we examined the genomic hybridization pattern of each cDNA probe to high molecular weight restriction fragments separated by pulsed-field gel electrophoresis. Serial hybridizations of the same filter have allowed construction of long-range Mlu I and Sfi I restriction maps spanning more than 500 kilobases. Finally, nonoverlapping portions of the cDNAs for both gpIIb and gpIIIa were used to probe Sfi I digests of genomic DNA separated by field-inversion gels. This confirmed that the genes are physically linked within the same 260-kilobase Sfi I fragment and suggests that the gene for gpIIb is located on the 3' side of the gene for gpIIIa. These results suggest that coordinate expression of gpIIb and gpIIIa may depend on physical proximity.

The effect of wall inertia on the self-excited oscillations in a collapsible channel flow is investigated by solving the full coupled two-dimensional membrane–flow equations. This is the continuation of a previous study in which self-excited oscillations were predicted in an asymmetric channel with a tensioned massless elastic membrane (Luo & Pedley 1996). It is found that a different type of self-excited oscillation, a form of flutter, is superposed on the original large-amplitude, low-frequency oscillations. Unlike the tension-induced oscillations, the flutter has high frequency, and grows with time from a small amplitude until it dominates the original slower mode. The critical value of tension below which oscillations arise (at fixed Reynolds number) is found to increase as the wall inertia is increased. The rate at which energy is (a) dissipated in the flow field and (b) transferred to the wall during the flutter is discussed, and results at different parameter values are compared with those of a massless membrane. There is also a discussion of whether the onset of flutter, or that of the slower oscillations, is correlated with the appearance of flow limitation, as is thought to be the case in the context of wheezing during forced expiration of air from the lungs.

A non-Newtonian constitutive equation for blood has been introduced in this paper. Using this equation, blood flow attributes such as velocity profiles, flowrate, pressure gradient, and wall shear stress in both straight and stenotic (constricted) tubes have been examined. Results showed that compared with Newtonian flow at the same flowrate, the non-Newtonian normally features larger pressure gradient, higher wall shear stress, and different velocity profile, especially in stenotic tube. In addition, the non-Newtonian stenotic flow appears to be more stable than Newtonian flow.

A non-Newtonian constitutive equation for blood has been introduced in this paper. Using this equation, blood flow attributes such as velocity profiles, flowrate, pressure gradient, and wall shear stress in both straight and stenotic (constricted) tubes have been examined. Results showed that compared with Newtonian flow at the same flowrate, the non-Newtonian normally features larger pressure gradient, higher wall shear stress, and different velocity profile, especially in stenotic tube. In addition, the non-Newtonian stenotic flow appears to be more stable than Newtonian flow.