Persistent infection of a bovine kidney cell line with Newcastle disease virus

Continuous passage of undiluted supernatant fluids from cultures of a bovine kidney cell line MDBK infected with the Herts 33 strain of NDV, led to the establishment of a carrier state [MDBKcs].The general properties of this virus-cell system were compared with those of a regulated-type of NDV persistent infection of MDBK cells [MDBKpi] which was accidentally induced in this laboratory in 1962 [ Edwards, 1972] .The intracellular polypeptide composition of the cell associated virus in MDBKpi was different from that in MDBKcs cells. In MDBKcs virus, the usual pattern of composition and distribution of NDV polypeptides was observed whereas the MDBKpi virus lacked the M protein which is necessary for viral assembly.Experiments using both RNA and protein synthesis inhibitors [actinomycin D and cycloheximide, respectively] failed to induce an increased release of infectious virus from MDBKpi cell cultures. This indicates that the blockage is not dependent on cellular RNA or protein synthesis.The presence of a cellular control mechanism of NDV replication was detected in the persistently infected MDBKcs cultures as well as in MDBK cells primarily infected with NDV and there is evidence that a similar mechanism occurs in MDBKpi cells. It is emphasised, however, that the cellular block does not prevent the release of fully infectious virus from primary or carrier state cultures.Although the virus released from MDBKpi does not undergo a productive replication cycle in permissive cell culture systems or in embryonated eggs, it is able to attach, replicate, haemadsorb and induce cell fusion at the first passage level. The available evidence suggests that a defect in the synthesis of M protein miight account for failure to assemble complete viral particles at the cell surface.Besides promoting the release of non -infectious particles, the absence of the viral Iii polypeptide may also be responsible for the intracellular accumulation of viral nucleocapsids. These structures were found to be of two different types, namely granular and smooth, according to the presence or absence of a sheath - covering the RNP component. The accumulation' observed in the nucleus of some cells in aged cultures was always restricted to smooth nucleocapsids. Furthermore, only the granular nucleocapsids were shown conclusively to be NDV-specific by immunoperoxidase techniques.Biochemical experiments on Herts NDV and MDBKcs virus, propagated in embryonated eggs, showed that both types consist of a mixture of two distinct kinds of virus particles. The first of these sedimented at a density of 1.12.in sucrose or tartrate gradients and revealed an unusual polypeptide composition including a significantly reduced NP/F peak, low haemagglutinin and neuraminidase activities, and law infectivity titres; whereas the virus sedimenting at a density of 1.18 was of the standard type.A viral inhibitory factor [VIA was detected in the supernatant fluids of MDBKcs cell cultures. This viral-induced component was NDV-specific, could not be sedimented by ultracentrifugation, and was able to protect indicator cell monolayers against infection by homologous virus but not by related or unrelated viruses.On the other hand, absence of the viral inhibitory factor in MDBKpi cell culture fluids suggested that a different mechanism is involved in the maintenance of the regulated type of infection.Unsuccessful attempts were made to transfect the putative integrated viral information in DIVA from MDBK cells persistently infected with NDV. However, the results of several experiments involving DNA analogues and the fact that a transient "cure" of MDBKpi monolayers was obtained after prolonged propagation seem to suggest that viral integration is a possible hypothesis, at least so far as regulated infections are concerned

SPICE implementation of a finite element method based model for bipolar power semiconductors

This paper describes the methodology associated with the practical implementation, in SPICE circuit simulator, of a Finite Element Method (FEM) based model developed for Bipolar Power Semiconductor (BPS) simulation. The methodology is based on a modular approach that associates each zone of the semiconductor to a subcircuit implemented into SPICE simulator. Modeling a semiconductor is based in the union of the set of subcircuit modules necessary to the different zones. Calculus of instantaneous distribution of lightly doped zones carriers (ambipolar diffusion equation (ADE) solution in space/time) is made with a group of subcircuit modules, analogue to FEM elements. The paper shows how each module is implemented and how easily elements with different sizes, topologies or physical properties are made. Remaining semiconductor zones (highly doped emitters narrow base and MOS zones) are modeled with subcircuits using classical approaches. Voltage drops are modeled with subcircuits implementing a Boltzmann approach for junctions and a Poisson approach for depletion zones. Description for obtaining each associated SPICE subcircuit is made. Global solution is approached by serial addition of these modules (each one directly related to one element of the domain). The paper concludes with simulations showing hole/electron distribution, in time/space, in low-doped zones of PIN Diodes, BJTs and IGBTs, as well as, corresponding dynamic commutation waveforms for current and voltage

Rei e «estado real» nos textos legislativos da Idade Média portuguesa.

Sin resume

A sociedade política joanina (1383 - 1433): Para uma visáo de conjunto.

Sin resume

Diplomática e História do Direito, raízes da «nova» História política*

Las ciencias de incidencia histórica (y entre ellas la Diplomática) como áreas en las que la tradición de los saberes es fuerte (Mabillon, João Pedro Ribeiro o Agustín Millares Carló, por ejemplo, siguen siendo referencias…) y en donde el Derecho como “Ciencia de lo continuo”: dos familias intelectuales que en Portugal, en los últimos años, parecen especialmente abocadas al diálogo interdisciplinar.The sciences in which the history is called (and among them the Diplomacy) as areas in which the tradition of knowlegde is strong (Mabillon, João Pedro Ribeiro or Agustín Millares Carló, for example, still constitute a reference…) and where the Law, as the “Science of the Continuum”: two intellectual families called to the interdisciplinar dialogue in the Portuguese scientific scene of the last years

Estimating bankruptcy using neural networks trained with hidden layer learning vector quantization

The Hidden Layer Learning Vector Quantization (HLVQ), a recent algorithm for training neural networks, is used to correct the output of traditional MultiLayer Preceptrons (MLP) in estimating the probability of company bankruptcy. It is shown that this method improves the results of traditional neural networks and outperforms substantially the discriminant analysis in predicting one-year advance bankruptcy. We also studied the effect of using unbalanced samples of healthy and bankrupted firms. The database used was Diane, which contains financial accounts of French firms. The sample is composed of all 583 industrial bankruptcies found in the database with more than 35 employees, that occurred in the 1999-2000 period. For the classification models we considered 30 financial ratios published by Coface available from Diane database, and additionally the Beaver (1966) ratio of Cash Earnings to Total Debt, the 5 ratios of Altman (1968) used in his Z-model and the size of the firms measured by the logarithm of sales. Attention was given to variable selection, data pre¬processing and feature selection to reduce the dimensionality of the problem

O responder controlado temporalmente: desdobramentos da pesquisa com a tarefa de bissecção

info:eu-repo/semantics/publishedVersio

Lenalidomide: An Alternative Treatment for Refractory Behçet’s Disease and Relapsing Polychondritis

Introduction:Behçet’s disease (BD) is a chronic systemic condition characterized by recurrent oral and genital ulcers, neurological and vascular manifestations, ocular and skin lesions, and a positive pathergy test. Mouth and genital ulcers with inflamed cartilage (MAGIC) syndrome is rare and consists of features of BD together with relapsing polychondritis. The treatment of this syndrome is similar that of BD and depends on disease expression and symptoms. Case Report: We report the case of a 50-year-old man diagnosed with BD with relapsing polychondritis (MAGIC syndrome) which had evolved over approximately 35 years, with exuberant and frequent oral and genital ulcers. Various treatments were unsuccessful and had adverse effects. Lenalidomide was initiated at a dose of 5 mg per day with remission of oral and genital ulcers and no haematological or adverse effects. Conclusion: BD is a complex disorder with a variety of presentations. Its treatment can be challenging but sometimes off-label drugs, like lenalidomide, can be effective