The Effect of Material and Geometrical Uncertainty on the Homogenized Properties of Graphene Sheet-Reinforced Composites

This paper focuses on the computational homogenization of graphene sheet-reinforced composites with randomly dispersed inclusions and uncertainty in the constituent materials. Material uncertainty of the matrix and of the graphene inclusions are considered separately and their relative effect on the homogenized properties is assessed. The uncertainty in the inclusion material is due to structural defects of the graphene lattice and is taken into account using random variables for each component of the elasticity matrix. Moreover, Monte Carlo simulation is used to extract the statistical characteristics of the homogenized properties of the composite material. The results lead to useful conclusions regarding the effect of material and geometrical uncertainty on the macroscopic properties of graphene sheet-reinforced composites.

Artificial Chiral Media Using Conical-Coil Wire Inclusions

The electromagnetic response of the electrically small conical wire coil as a chiral inclusion is described. An existing model of the helical coil wire inclusion is extended to model the conical coil wire inclusion, using the Method of Moments (MoM) to determine the dominant resonant circuit impedance of the inclusion. Material parameters are determined using mixing relations with polarizability coefficients expressed for the conical coil inclusion geometry. The polarization conversion of a dielectric slab loaded with conical coil inclusions is predicted and compared to simulated results using a forward scattering technique.

CYTOLOGICAL AND CYTOCHEMICAL STUDIES OF GREEN MONKEY KIDNEY CELLS INFECTED IN VITRO WITH SIMIAN VIRUS 40

Cytological and cytochemical studies of green monkey kidney cells infected with SV40 virus indicated that the type of lesion produced was influenced by the multiplicity of infection and that the lesions appeared later and progressed more slowly when the inoculum was diluted. The earliest change consisted of enlargement of ribonucleoprotein-containing spherules in the nucleolus (nucleolini). This was followed by rarefaction, with or without condensation, of the chromatin and the appearance of one or more homogeneous masses of inclusion material containing DNA, RNA, and non-histone protein which eventually filled the nucleus. In some instances the chromatin appeared to be directly transformed into inclusion material. In the later stages of infection, the ribonucleoprotein of the nucleolini was no longer stainable and material resembling the nucleoprotein of the intranuclear inclusions was found in the nucleolar vacuoles and in the cytoplasm. The nucleic acids in the inclusions were stained by toluidine blue, toluidine blue-molybdate, the Feulgen stain, and by methyl green. The stainable material was extractable by nuclease digestion or by hot trichloroacetic acid. Green or yellowish green staining by acridine orange was apparently due to binding of dye by protein and not by nucleic acids since the staining reaction was not reduced by extraction of nucleic acids by hot trichloroacetic acid. Extraction with pepsin in combination with ribonuclease or deoxyribonuclease removed practically all the inclusions from the cells; consequently they could not be stained with acridine orange. The cytochemical studies suggest that the use of pepsin together with nuclease is not a meaningful technique.

Fine Structure of Cellular Inclusions in Measles Virus Infections

Cells which are infected with measles virus have been known for some time to contain inclusion material that is distinguishable from normal cellular components by application of traditional staining methods and observation in the light microscope. The fine structure of the inclusion material contained in HeLa cells infected with Edmonston strain of measles virus has been examined in the electron microscope. Two steps have been found necessary in this study: (1) the recognition by phase-contrast microscopy of the living cell of bodies that are defined as inclusion material when the cells are classically stained; and (2) the recognition in the electron microscope of inclusion-body material that had previously been identified in the living cell. The fine structure of the nuclear and cytoplasmic inclusion material in osmium-treated cells was found to consist mainly of randomly arrayed filaments of low electron density. Dense, highly ordered arrays of filaments were found near the center of the nuclear inclusions, sometimes as a two-dimensional, nearly orthogonal arrangement. If the size of the measles virus is taken to be around 100 mµ in diameter, the strands seen in the inclusions cannot be fully formed virus.

THE CELLULAR CHANGES PRODUCED IN TISSUE CULTURES BY HERPES B VIRUS CORRELATED WITH THE CONCURRENT MULTIPLICATION OF THE VIRUS

A sequential study is reported of the morphological changes occurring after herpes B virus infection of cells as revealed in ultrathin sections under the electron microscope. Monolayer cultures of renal epithelial cells prepared from the natural host of the virus, the monkey, were infected, and the cellular alterations were correlated with the appearance of infective virus in the culture fluids. The morphological changes consisted in swelling of the cells and disappearance of the nucleolus, followed by margination and gradual decrease of the nuclear chromatin. The inclusion material corresponded to the clear central areas of the nucleus, where the chromatin had disappeared. In the late stages of infection this inclusion material filled the nucleus and formed a classical type A inclusion body. Characteristic particles appeared in the nucleus and cytoplasm of the infected cells a few hours after inoculation. They had a dense center surrounded by one or two membranes. Those with one membrane ranged in size from 60 to 100 mµ and those with two from 120 to 180 mµ. Particles showing the same wide variation in size and structure were seen both in the nucleus and in the cytoplasm. They were first visible on the external surface of the swollen but intact cells at about the same time new infective virus became detectable in the culture fluid. A small number of the extracellular, and cytoplasmic, virus particles appeared "binucleated," containing two central bodies, each having its own membrane, both being surrounded by a single external coat. About 180 mµ in diameter, they were randomly distributed among the "mononucleated" particles.