Recent molecular evidence suggests an association with a new herpesvirus, Kaposi's sarcoma-associated herpesvirus (KSHV/HHV-8), and primary effusion lymphomas (PELs). PELs have a characteristic morphology, phenotype, and clinical presentation, with malignant effusions in the absence of a contiguous solid tumor mass. We have established a cell line (KS-1) from a KSHV-positive human immunodeficiency virus (HIV)-negative patient with pleural cavity-based lymphoma that was passaged into triple-immunodeficient BNX mice. In contrast to cell lines from body cavity-based lymphomas derived from HIV-positive individuals that contain both KSHV and Epstein Barr viral genome, these cells contain only KSHV, allowing for uncontaminated virologic studies. Ultrastructural examination identified malignant cells with features of late differentiating B cells (immunoblasts). Cells with viral cytopathic effect contained typical 110-nm intranuclear herpesvirus nucleocapsids and complete cytoplasmic virions, confirming the association of PEL with KSHV.
Kaposi's sarcoma (KS) has been shown by molecular techniques to be associated with infection with human herpesvirus 8 (HHV8/KSHV), but specific ultrastructural characterization of the virus has been impaired by the frequent presence in these lesions of other herpesviruses, particularly cytomegalovirus (CMV). Since the ultrastructural appearance of HHV8/KSHV has been studied in the cell line KS‐1 uninfected with other viruses including CMV, it was possible to undertake a comparative study of CMV and HHV8/KSHV in KS lesions. HHV8/KSHV was sparsely present and lytic infection was restricted to endothelial cells. The following specific ultrastructural features allowed distinction between HHV8/KSHV and CMV: the viral particles were more delicate and less numerous in cases of HHV8/KSHV infection; the viral tegument was more electron‐dense in CMV than in HHV8/KSHV; dense bodies characteristic of CMV were absent in HHV/KSHV; complete CMV viral particles were more variable in size and generally larger (150–200 nm) than HHV8/KSHV (120–150 nm); and finally, the viral envelope was more pleomorphic in CMV than in KSHV/HHV8. Similarities between CMV and HHV8/KSHV included the basic structure of the nucleocapsids and the presence of capsids lacking central DNA cores (so‐called non‐infectious enveloped particles). These observations show that electron microscopy can be used to identify HHV8/KSHV and confirm the relationship between HHV8/KSHV and KS. © 1997 John Wiley & Sons, Ltd.
After ultrathin sections are cut, contamination can result not only from the staining and rinsing solutions but also from improper handling technique. A new procedure is described which is simple to perform and enables one to obtain cleaner sections for EM examination.Commercially available instruments and materials (Ted Pella, Inc.) are used for this procedure: A Pelco Vacuum Device (fig. 1) is connected by flexible plastic tubing to an adaptor which can accept various sized metal needles. The vacuum can be finger-tip controlled at the aperture within the adaptor. Cohen-Pelco Tabbed Grids are used for section support. A flat, silicone rubber grid holder is used for staining and rinsing of several grids at one time.
Warpage after molding is a critical issuefor array packages due to singulation and soldering requirement in subsequent assembly. Warpage is greatly affected by package geometries, such as dimensions ofmatrix block, pad, die, andpassive components, as well as molding compoundproperties. One set ofmolding compoundproperties may generate very low warpage in one array package, but generate unacceptable warpage in another. To achieve minimum warpage in all geometry variations, molding compoundproperties have to be tunedfor each package. In this paper, molding compounds with multifunctional epoxies and hardeners were developed. The curing shrinkage and Tg ofthe molding compounds were easily adjusted while other major properties kept consistent. Methodology taken to tackle the issue was discussed. Warpage ofarray blockslstrips built with modified molding compounds was measured by shadow Moire method to correlate warpage with molding compoundproperties. Finite element analysis was also performed to predict and correlate effects ofmodulus, CTE, and shrinkage on warpage, as well asfurther compound modifications Introduction and background investigation Warpage is one of the major concerns when manufacturing BGA and QFN based array packages. Obtaining and maintaining a reasonably flat package is critical to subsequent singulation and board level soldering process. Warpage is introduced into a package because of the curing and cooling of adhesives, such as molding compounds. After the gel point, package components are bound together by the cross-linked polymer network. No component can expand or shrink freely. Due to the differences in chemical shrinkage and/or coefficient of thermal expansion (CTE) of package components, warpage is generated to couple the differences in dimensional change and remain the bonds. In a typical array package, warpage is seen in either a "crying" face or a "smiling" face. Unless purposely designed and processed, a flat package usually means debonding inside the package.The warpage shape depends on both geometries and properties of package components as well as process conditions. The package geometry is usually predefined in the design phase and difficult to change. The process conditions are commonly industry standard and based on materials intrinsic properties. It costs a lot to change the process because of additional qualification and capital investment required. The only feasible route to be able to adjust the package warpage is to play with the materials properties of package components. Molding compounds, as the largest components in packages, usually dominate the warpage. Molding compounds are composite materials composed of resins, hardeners, fillers, catalysts, coupling/release
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