Subject Index of Volume 32

Subject Index

Subject Index of Volume 32     

Index to Volume 31 (2001)

Subject Index

Index to Volume 31 (2001)     

Alternate metal virtual ground (AMG)-a new scaling concept for veryhigh-density EPROMs

A new erasable programmable read-only memory (EPROM) array concept that reduces the cell size to the poly pitch in both directions is introduced. The key concepts that made the dramatic scaling possible are the virtual ground array with one metal line for every two diffusion bit lines, the segmentation of every other bit line, and the fieldless array. The cell size on 0.8-μm technology is 2.56 μm² and a 1-μmm² cell is under development on a 0.5-μm technology for the 64-Mb product. These cells are smaller by a factor of 2-3 than the standard EPROM cell on the same technology. The new array concept and its advantages are expandable to flash memories     

The femoral artery-femoral vein polytetrafluoroethylene graft: a 14-year retrospective study

The purpose of this study was to determine the relationship between sarcoma tumor grade and the quantitative tumor metabolism value for [F-18]fluorodeoxyglucose (FDG) determined by positron emission tomography (PET) imaging. Seventy patients with bone or soft-tissue sarcomas underwent PET scanning with quantitative determination of tumor FDG metabolic rate (MRFDG) before treatment. MRFDG (micromol/g/min) for each tumor was compared with National Cancer Institute tumor grade, S-phase percentage, and percentage of aneuploidy of the tumor population. The pretreatment quantitative determination of tumor MRFDG by PET correlates strongly with tumor grade but not with the other selected histopathological tumor correlates. In addition, overlap of MRFDG PET values with tumor grade suggests that PET, an objective tumor measurement, may provide an alternative means of assessing tumor biological potential or may have the potential to overcome some of the limitations of traditional pathological evaluation. FDG PET can uniquely provide a metabolic profile of a diverse group of sarcomas noninvasively and provide clinically relevant tumor biological information.     

Permanganate oxidation of oleic acid using emulsion technology

Free oleic acid is emulsified in water and oxidized using potassium permanganate, to azelaic and pelargonic acids together with dihydroxy-, ketohydroxy-and diketo-stearic acids at neutral pH. The yield and the products distribution are controlled by: the type of emulsifier and its concentration; the oleic acid concentration in the emulsion; and the oleic acid-oxidant ratio.     

A complete scheme for creating predefined networks of individual carbon nanotubes

We describe and demonstrate a method of creating arrays of patterned, individual, single-walled carbon nanotubes, including the spectroscopic mapping of the array. The process consists of creating networks of nanotubes suspended between silicon pillars, which are then transferred onto other substrates by an innovative process of direct stamping. Raman spectroscopy is used to spatially map and assign the specific properties of the suspended network prior to transfer. This method provides a simple and inexpensive means for deriving nanoscale devices utilizing individually assigned carbon nanotubes in a robust and non-surface-specific technique.     

Closed form solutions for water-filling problems in?optimization and?game frameworks

We study power control in optimization and game frameworks. In the optimization framework there is a single decision maker who assigns network resources and in the game framework users share the network resources according to Nash equilibrium. The solution of these problems is based on so-called water-filling technique, which in turn uses bisection method for solution of non-linear equations for Lagrange multipliers. Here we provide a closed form solution to the water-filling problem, which allows us to solve it in a finite number of operations. Also, we produce a closed form solution for the Nash equilibrium in symmetric Gaussian interference game with an arbitrary number of users. Even though the game is symmetric, there is an intrinsic hierarchical structure induced by the quantity of the resources available to the users. We use this hierarchical structure to perform a successive reduction of the game. In addition to its mathematical beauty, the explicit solution allows one to study limiting cases when the crosstalk coefficient is either small or large. We provide an alternative simple proof of the convergence of the Iterative Water Filling Algorithm. Furthermore, it turns out that the convergence of Iterative Water Filling Algorithm slows down when the crosstalk coefficient is large. Using the closed form solution, we can avoid this problem. Finally, we compare the non-cooperative approach with the cooperative approach and show that the non-cooperative approach results in a more fair resource distribution.     

Mechanical and elastic properties of fine-grained polycrystalline scandia and erbia as determined by indentation techniques

The Young's moduli, E, and nanoindentation, NI, stress-strain curves of fine-grained scandia, Sc₂O₃, and erbia, Er₂O₃, were determined using spherical indenters with radii of 1.4 μm and 5 μm. The Young's moduli measured with the spherical indenters, were comparable to those measured by a Berkovich tip, and by ultrasound. This work further validates the use of S vs. a plots to measure the Young's moduli of polycrystalline ceramics. A major advantage of using this technique is the possibility of determining NI stress-strain curves and concomitant yield points, apparent strain hardening rates, etc. for the first time. Both the elastic moduli and the yield stresses were affected by the degree of surface polishing and tip size. The most reproducible and reliable results were obtained with the sharper nanoindenter and the best surface finish. The Vickers hardness and indentation fracture toughness values extracted from the Vickers indentations are comparable to the literature results.     

Biodegradable zinc-based materials with a polymer coating designed for biomedical applications

Over the last decades, biodegradable metals have gained popularity for biomedical applications due to their ability to assist in tissue healing. These materials degrade in vivo, while the corrosion products formed are either absorbed or excreted by the body, and no further surgical intervention is required for removal. Intensive research has been carried out mainly on degradable biomaterials based on Mg and Fe. In recent years, zinc-based degradable biomaterials have been explored by the biomedical community for their intrinsic physiological relevance, desirable biocompatibility, intermediate degradation rate, tuneable mechanical properties and pro-regeneration properties. Since pure Zn does not exhibit sufficient mechanical properties for orthopedic applications, various Zn alloys with better properties are being developed. In this work, the combined effect of minor Fe addition to Zn and a polyethyleneglycol (PEG) coating on the surface morphology, degradation, cytotoxicity and mechanical properties of Zn-based materials was studied. There are several studies regarding the influence of the production of Zn alloys, but the effect of polymer coating on the properties of Zn-based materials has not been reported yet. A positive effect of Fe addition and polymer coating on the degradation rate and mechanical properties was observed. However, a reduction in biocompatibility was also detected.     

A Novel Rodent Model of Hypertensive Cerebral Small Vessel Disease with White Matter Hyperintensities and Peripheral Oxidative Stress

Cerebral small vessel disease (CSVD) is the second most common cause of stroke and a major contributor to dementia. Manifestations of CSVD include cerebral microbleeds, intracerebral hemorrhages (ICH), lacunar infarcts, white matter hyperintensities (WMH) and enlarged perivascular spaces. Chronic hypertensive models have been found to reproduce most key features of the disease. Nevertheless, no animal models have been identified to reflect all different aspects of the human disease. Here, we described a novel model for CSVD using salt-sensitive ‘Sabra’ hypertension-prone rats (SBH/y), which display chronic hypertension and enhanced peripheral oxidative stress. SBH/y rats were either administered deoxycorticosteroid acetate (DOCA) (referred to as SBH/y-DOCA rats) or sham-operated and provided with 1% NaCl in drinking water. Rats underwent neurological assessment and behavioral testing, followed by ex vivo MRI and biochemical and histological analyses. SBH/y-DOCA rats show a neurological decline and cognitive impairment and present multiple cerebrovascular pathologies associated with CSVD, such as ICH, lacunes, enlarged perivascular spaces, blood vessel stenosis, BBB permeability and inflammation. Remarkably, SBH/y-DOCA rats show severe white matter pathology as well as WMH, which are rarely reported in commonly used models. Our model may serve as a novel platform for further understanding the mechanisms underlying CSVD and for testing novel therapeutics.