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Addressable quantum states well isolated from the environment are of considerable interest for quantum information science and technology. Carbon nanotubes are an appealing system, since a perfect crystal can be grown without any missing atoms and its cylindrical structure prevents ill-defined atomic arrangement at the surface. Here, we develop a reliable process to fabricate compact multielectrode circuits that can sustain the harsh conditions of the nanotube growth. Nanotubes are suspended over multiple gate electrodes, which are themselves structured over narrow dielectric ridges to reduce the effect of the charge fluctuators of the substrate. We measure high-quality double- and triple-quantum dot charge stability diagrams. Transport measurements through the triple-quantum dot indicate long-range tunneling of single electrons between the left and right quantum dots. This work paves the way to the realization of a new generation of condensed-matter devices in an ultraclean environment, including spin qubits, mechanical qubits, and quantum simulators.

Skin fibroblasts from normal individuals and a patient with the infantile form of sialidosis were cultured for up to 72h in medium containing [3H]-N-acetylmannosamine. The sialidosis fibroblasts consistently accumulated more labeled compound(s) than the control cells, i.e. 37–88% more cpm per mg protein. Precipitation of sonicates of these cells with 10% trichloracetic acid, TCA, demonstrated that the excess radioactivity in the sialidosis fibroblasts was in one or more TCA soluble compounds. There was no detectable difference in the amount of label in the TCA insoluble material. The TCA soluble, labeled, material from the sialidosis and the control fibroblasts was separated, isolated and purified on AG1-X8, QAE Sephadex A-25 and Bio-Gel P-4 chromatography columns. Analysis of the isolated material showed the excess radioactivity in the sialidosis fibroblasts to be due to increased levels of [3H]sialic acid covalently bound to a variety of anionic sialyl conjugates. These compounds have been separated and partially purified. Finally, acid hydrolysis and chromatographic analysis of the TCA insoluble fractions showed that greater than 80% of the label in this material was also due to [3H]sialic acid. There was no detectable difference between the control and the sialidosis patient in the amount of label in this fraction.

Skin fibroblasts from normal individuals and a patient with the infantile form of sialidosis were cultured for up to 72h in medium containing [3H]-N-acetylmannosamine. The sialidosis fibroblasts consistently accumulated more labeled compound(s) than the control cells, i.e. 37–88% more cpm per mg protein. Precipitation of sonicates of these cells with 10% trichloracetic acid, TCA, demonstrated that the excess radioactivity in the sialidosis fibroblasts was in one or more TCA soluble compounds. There was no detectable difference in the amount of label in the TCA insoluble material.

The average sphingomyelinase activity of fibroblasts obtained from 12 Niemann-Pick type C patients was 37.9% of that of normal fibroblasts (27.2versus72nmol(mg protein)-1h-1) when the cells were cultured in minimum essential medium containing 13% fetal bovine serum. Following replacement of the above medium with medium in which the lipoprotein fraction had been removed from the fetal bovine serum, the sphingomyelinase activity rose over a 7-day period from about 1/3 of normal to normal or above. Upon reintroduction of medium containing 10% fetal bovine serum which had not been extracted, the sphingomyelinase activity of the Niemann-Pick type C cells again fell within 48h to 30% of the normal controls. In contrast, cell lines from patients with either Niemann-Pick Type A or B were not influenced by the presence or the absence of lipoprotein, i.e. lacked sphingomyelinase activity under all culture conditions examined. Histochemical staining with filipin showed an inverse relationship between the sphingomyelinase activity and intracellular, free, unesterified, cholesterol level. Moreover, immunochemical staining with an antibody against a lysosomal membrane protein provided direct evidence that the accumulation of unesterified cholesterol in cells cultured in regular (non-extracted) medium occurred within lysosomes and/or related organelles.

A major trend in the thermal spray industry has been to increase the gas jet velocity to obtain better coating attributes. One emerging technology now used in industry is the high-velocity oxygen fuel process (HVOF). High-velocity spray guns combine oxygen and a fuel gas to generate heat and extremely high particle velocities. In this study, Inconel 718 powder was deposited on steel substrates. The primary coating function was electrical resistivity for a heater application. Experiments were conducted using a Taguchi L8 statistical fractional/factorial design parametric study. The Taguchi experiment evaluated the effect of six HVOF processing variables on the measured responses. The parameters were oxygen flow, fuel flow, air envelope gas flow, powder feed rate, spray distance, and nozzle configuration. The coatings were characterized by hardness tests, surface profilometry, optical metallography, and image analysis. This article investigates coating hardness, porosity, surface roughness, deposition efficiency, and microstructure with respect to the influence of the processing parameters. Analytical studies were conducted to investigate gas, particle, and coating dynamics for two of the HVOF thermal spray experiments.

Diffraction arid partial coherence cause errors in the measurement of small-scale photographic detail by microdensitometers and projection systems. The optical imaging nonlinearities can be avoided by scanning the silver distribution with a narrow beam of energetic electrons and counting the secondary quanta that are excited. It is found that the number of low energy (secondary) and high energy (backscattered) electrons emitted from various emulsion types as well as the characteristic Ag x-ray fluorescence are measures of the local silver concentration. A mechanism for the secondary electron contrast, which is only in part due to surface relief, is proposed. Spatial frequencies up to 2280 p/mm have been retrieved by such scanning electron beam probes.

A NUMBER of compounds were compared to glucose as substrates for the biogenesis of ethylene in Penicillium digitatum. Several compounds of low molecular weight gave a greater production of ethylene by the organism than did an equimolar amount of glucose. D,L-Serine, L-serine and glycine proved to be better substrates for this purpose, with D,L-serine being the best.

The cherry red spotmyoclonus syndrome has been reported in at least 11 individuals in the past 20 years. The symptoms usually have their onset in the second decade of life and include macular cherry-red spots, myoclonus and increased deep tendon reflexes and no dementia. Recently neuraminidase deficiency has been documented in some of these patients. This report is of a.31 year old male with macular cherry-red spots, hyperreflexia and myoclonus (tremors and sudden quick jerks of both hands) without dementia. An older brother who had progressive myoclonus died at age 33 with myoclonic seizures. Homogenates of cultured fibroblasts from the proband exhibited a marked deficiency of neuraminidase activity. The neuraminidase activities in fibroblasts from the proband's parents and in two children of the proband were in the intermediate range. The cherry red spot-myoclonus syndrome is clinically distinct from Mucolipidosis I in which neuraminidase deficiency has also been reported.

Several letters to the editor are presented in response to articles published in the previous issues including "Genocide of the Armenian People by the Turks in 1915," by Blanche Wiesen Cook in the previous issue, "Women and Peace: The Legacy," in the Winter 2006 issue, "Silence = War," in the Winter 2006 issue, "Tough As Iron," in the Fall 2005 issue, "Jane Doe's Choice," in the Winter 2006 issue and "A Shot Against Cervical Cancer," in the previous issue.