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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 5996-6000 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Design, simulation, and experimental investigations of a direct current to a single flux quantum converter loaded with a Josephson transmission line and driven by an external 70 GHz microwave oscillator are reported. The test circuit includes nine YBaCuO Josephson junctions aligned on the grain boundary of a 0°–32° asymmetric Y-ZrO2 bicrystal substrate. The performance of such converters is important for the development of the fast Josephson samplers required for testing of high-Tc rapid single flux quantum circuits in high-speed digital superconducting electronics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 63 (1993), S. 3218-3220 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A new element for superconducting electronic circuitry—a variable attenuator—has been proposed, designed, and successfully tested. The principle of operation is based on the change in the microwave impedance of a superconductor-insulator-superconductor (SIS) Josephson tunnel junction when dc biased at different points in the current-voltage characteristic. Both numerical calculations based on the Tien–Gordon theory and 70-GHz microwave experiments have confirmed the wide dynamic range (more than 15-dB attenuation for one stage) and the low insertion loss in the "open'' state. The performance of a fully integrated submillimeter receiver circuit which comprises a flux–flow oscillator (FFO) as local oscillator, a superconducting variable attenuator, and a microwave SIS detector with tuned-out capacitance is also reported.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 59 (1991), S. 866-868 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report the operation of and, exor, exnor, and inverting gates in a circuit architecture suitable for the set of all Boolean gates. Series arrays of YBa2Cu3O7−x dc superconducting quantum interference devices with integrated coils exhibit sufficient modulation to allow low-speed tests demonstrating gate logic, and lack of oscillation or latching. The best inverter operated (without load) at 36 μV, with 2 nW of gate dissipation.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have studied the response of YBa2Cu3O7 step-edge junctions to low-intensity millimeter-wave radiation in the temperature range from 4 to 80 K. The linewidth of the Josephson oscillations derived from the resonant part of the response at voltages V(approximately-equal-to)(h/2e)f is shown to be determined by thermal fluctuations at liquid nitrogen temperatures. At lower temperatures the observed linewidth increases indicating that low-frequency fluctuations become dominant in the junction as the temperature is reduced. Due to an inhomogeneous spatial distribution of the current the step-edge junction might be considered as a multijunction multiloop interferometer and the excess noise can be discussed in terms of spontaneous transitions between the different states of these interferometers.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 580 (1990), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 42 (1994), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of clinical periodontology 20 (1993), S. 0 
    ISSN: 1600-051X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract The purpose of this study was to determine the prevalence and distribution of 5 bacterial pathogens in subgingival plaque, their relationship with each other and probing depth. Plaque was collected from 6905 sites in 938 subjects. A bacterial concentration fluorescence immunoassay and bacterial specific monoclonal antibodies were used to determine the presence and level of P. gingivalis (Pg), A. actinomycetemcomitans (Aa), P. intermedia (Pi), E. carrodens (Ec) and F. nucleatum (Fn) in each plaque sample. The prevalence in subjects was lowest for Pg (32%) and highest for Ec (49%). The site-based frequency distribution of these bacterial species ranged from 10.3% for Pg to 18.7% for Ec. Pi and Ec were the bacterial combination most often found together in a subject (27.2%). While 64.0% of the sites were without any of the 5 bacterial species evaluated, 20.2% had only 1 of the 5 bacterial species evaluated. The remaining 15.8% of sites had at least 2 bacteria species present. There was a general linear association of the detection level of bacterial species and probing depth. The odds ratios were 3.9 (Pg). 3.0 (Aa), 4.0 (Pi). 2.7 (Ec) and 2.8 (Fn) of finding high levels of these bacterial pathogens at 〉 5 mm probing depth (p≤ 0.01). Mean probing depth at molar sites without a specific bacteria was greater (p≤ 0.01) in subjects wish a specific bacterium compared to molar sites in subjects without the bacteria. The observation that these 5 bacterial species frequently inhabit the subgingival environment, yet are not associated with advanced disease, suggest that a susceptible host is required, in addition to a “pathogenic bacteria”, before disease progression may occur.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-2307
    Keywords: L-pyruvate kinase ; M2-pyruvate kinase ; Kidney neoplasms ; Carbohydrate metabolism ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Using immunohistochemical and enzyme biochemical methods we investigated the expression of L- and M2-pyruvate kinase (PK) in normal renal tissue, renal cell carcinomas (RCCs; of clear cell, chromophilic cell and mixed cell type) and RCC metastases. L-PK was expressed in the proximal tubules of normal renal tissue and, to a variable extent, in 23/25 primary RCCs, in 1 RCC recurrence and in 10 RCC metastases. Staining intensity and percentage of stained tissue did not correlate with tumour grade. One renal oncocytoma and all extrarenal malignancies examined lacked L-PK immunoreactivity. M2-PK was mainly expressed in the distal tubules of the normal kidney and was found in all renal tumours as well as extrarenal malignancies. Quantitative biochemical investigations yielded a two- to seventeen-fold increase in PK activity in RCCs compared to the normal renal cortex taken from the same patient, whereas fructose-1,6-bisphosphatase and cytosolic glycerol-3-phosphate dehydrogenase activity was dramatically lower in RCCs. Otherwise, the activity of all other enzymes investigated (glucose-6-phosphate dehydrogenase, enolase and lactate dehydrogenase) was not significantly changed in the RCCs. The immunocytochemical results suggest that L-PK is a useful marker for RCC and its metastases, if acetone-fixed tissue is available. The quantitative changes of the concentration of PK and other enzymes in RCCs when compared with normal renal tissue probably reflect metabolic alterations related to tumour growth.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A multi-cup sediment trap was deployed at 250m in the shelf area off Kapp Norvegia, Weddell Sea (630 m water depth) to determine the relative importance of water mass advection, sea ice movement, phytoplankton biomass and plankton feeding. Short-term fluctuations in sedimentation were determined using a sampling frequency of 2.7 days over 54 days during January and February 1988. Three periods of enhanced sedimentation were associated with water mass exchange, settling of diatoms following break-up of ice cover and release of fecal matter by krill feeding on particulate matter derived from phytoplankton and ice algae. An initial sedimentation pulse (28 Jan) was mainly due to sinking pelagic diatoms and krill fecal strings containing algae released from sea ice passing over the trap position. The δ13C-composition of the sedimented organic carbon was about-24‰. The isotope ratio decreased sharply by about 5.5‰ at the end of the first pulse indicating the source of sinking matter becoming pelagic diatoms of the retreating ice-edge. At this time the diatom Corethron criophilum contributed a very high proportion of the organic flux causing an increase of the opal/Corg ratios. The second pulse (6 Feb) was due to empty diatom frustules, minipellets and small planktonic aggregates. Much of the organic carbon was transported by round fecal pellets. During the third pulse (14 Feb), round fecal pellets transported even more; the percentage of C. criophilum to the diatom organic carbon flux was more than 80% (〉2mg C m−2 day−1).
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0332-1649
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: A promising approach for the solution of the electrocardiographic inverse problem is the calculation of the cardiac activation sequence from body surface potential (BSP) mapping data. Here, a two-fold regularization scheme is applied in order to stabilize the inverse solution of this intrinsically ill-posed problem. The solution of the inverse problem is defined by the minimum of a non-linear cost function. The L-curve method can be applied for regularization parameter determination. Solving the optimization problem by a Newton-like method, the L-curve may be of pronged shape. Then a numerically unique determination of the optimal regularization parameter will become difficult. This problem can be avoided applying an iterative linearized algorithm. It is shown that activation time imaging due to temporal and spatial regularization is stable with respect to large model errors. Even neglecting cardiac anisotropy in activation time imaging results in an acceptable inverse solution.
    Type of Medium: Electronic Resource
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