To develop a herpes virus vaccine that can induce immunity for an extended period, a recombinant Marek's disease (MD) virus (MDV) CVI-988 strain expressing infectious bursal disease virus (IBDV) host-protective antigen VP2 at the US2 site (rMDV) was developed under the control of an SV40 early promoter. Chickens vaccinated with the rMDV showed no clinical signs and no mortality and 55% of the chickens were considered protected histopathologically after challenge with very virulent IBDV (vvIBDV), whereas all of the chickens vaccinated with the conventional IBDV vaccine showed no clinical signs and were protected. Chickens vaccinated with the CVI-988 or chickens in the challenge control showed severe clinical signs and high mortality (70-75%) and none of them were protected. Also, the rMDV conferred full protection to chickens against vvMDV just as the CVI-988 strain did, whereas 90% of the challenge control chickens died of MD. Antibody levels against IBDV and MDV following the vaccination increased continuously for at least 10 weeks. No histopathological lesions in the rMDV-vaccinated chickens and no contact transmission of the rMDV to their penmates were confirmed. These results demonstrate that an effective and safe recombinant herpesvirus-based IBD vaccine could be constructed by expressing the VP2 antigen at the US2 site of the CVI-988 vaccine strain.
Animal bodies are shaped by skeletons, which are built inside the body by biomineralization of condensed mesenchymal cells in vertebrates [1, 2] and echinoderms [3, 4], or outside the body by apical secretion of extracellular matrices by epidermal cell layers in arthropods [5]. In each case, the skeletons' shapes are a direct reflection of the pattern of skeleton-producing cells [6]. Here we report a newly discovered mode of skeleton formation: assembly of sponges' mineralized skeletal elements (spicules) in locations distant from where they were produced. Although it was known that internal skeletons of sponges consist of spicules assembled into large pole-and-beam structures with a variety of morphologies [7-10], the spicule assembly process (i.e., how spicules become held up and connected basically in staggered tandem) and what types of cells act in this process remained unexplored. Here we found that mature spicules are dynamically transported from where they were produced and then pierce through outer epithelia, and their basal ends become fixed to substrate or connected with such fixed spicules. Newly discovered "transport cells" mediate spicule movement and the "pierce" step, and collagen-secreting basal-epithelial cells fix spicules to the substratum, suggesting that the processes of spiculous skeleton construction are mediated separately by specialized cells. Division of labor by manufacturer, transporter, and cementer cells, and iteration of the sequential mechanical reactions of "transport," "pierce," "raise up," and "cementation," allows construction of the spiculous skeleton spicule by spicule as a self-organized biological structure, with the great plasticity in size and shape required for indeterminate growth, and generating the great morphological diversity of individual sponges.
Many of practical design specifications are provided by finite frequency properties described by inequalities over restricted finite frequency intervals. A quadratic differential form (QDF) is a useful algebraic tool to characterize energy and power functions when we consider dissipation theory based on the behavioral approach. In this paper, we investigate time domain characterizations of the finite frequency domain inequalities (FFDIs) using QDFs. QDFs allow us to derive a clear characterization of the FFDIs using some inequality in terms of them as a main result. This characterization leads to a physical interpretation in terms of the dissipation inequality with the compensating rate which guarantees dissipativity of a behavior with some rate constraints. Such an interpretation has not been clarified by the previous studies of finite frequency properties. The aforementioned characterization yields an LMI condition whose solvability is equivalent to the FFDIs. This can be regarded as the finite frequency KYP lemma in the behavioral framework.
The amount of carbon in GaAs and (Al,Ga)As films depends on the orientation of crystals grown by metalorganic chemical vapor deposition. We investigated the relation between the incorporation of carbon and the orientation of crystals using (100), (311)A, and (311)B substrates. The concentration of electrons on (311)B substrates of unintentionally doped films was higher than those of the films on (100) and (311)A substrates. The films grown on (311)B substrates did not show p-type behavior even when they were grown with a fairly low V/III ratio. The relative intensity of the free-to-carbon acceptor luminescence of the films grown on (311)B substrates was smaller than that of films grown on the other substrates. This is consistent with the results of carbon contamination indicated by secondary ion mass spectra. Furthermore, a reduced peak in photoluminescence caused by defects was observed when (311)B substrates were used.
In this paper, we consider the generalized Lyapunov stability analysis for a discrete-time system described by a high order difference-algebraic equation. In the behavioral approach, a Lyapunov function is characterized in terms of a quadratic difference form. As a main result, we derive a generalized Lyapunov stability theorem that the asymptotic stability of a behavior is equivalent to the solvability of the two-variable polynomial Lyapunov equation (TVPLE) whose solution induces the Lyapunov function. Moreover, we derive another asymptotic stability condition by using a polynomial matrix solution of the one-variable dipolynomial Lyapunov equation which is reduced from the TVPLE.
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