Ladder Arrays Research Articles

Epstein-Barr virus infection in carcinoma of the salivary gland.

Undifferentiated carcinoma of the parotid gland contains clonal Epstein-Barr virus episomes without ladder arrays of restriction enzyme fragments representing virion DNA. Analysis of Epstein-Barr virus transcription in situ in parotid carcinoma specimens revealed that the EBER RNAs, latent membrane protein mRNA, and the BamHI-A rightward reading frame, BARF0, are expressed in the malignant epithelial cells.

Experiments and simulations on Josephson junction ladder arrays

We report experiments and dynamic simulations on the magnetoresistance of ladder arrays of Josephson junctions. The simulations were performed using a very efficient algorithm. The experiments and simulations show the same features and these can be understood qualitatively in terms of static properties of the vortex gas.

Dynamic simulations of arrays of Josephson junctions.

First we introduce a very efficient algorithm for dynamic simulations of a wide class of arrays of Josephson junctions with realistic boundaries. With this algorithm one can also represent current-biased arrays with periodic boundaries. Next we present results of extensive simulations of ladder arrays. We evaluate the resistance as a function of magnetic field and find striking differences between different geometries.

Phase coherence and dynamics in weakly-coupled periodic and quasiperiodic superconductor arrays

We have fabricated and studied the transport properties of arrays of proximity-coupled superconductor islands arranged in a quasiperiodic Penrose tile geometry. In the magnetic field response, we identify coarse structure arising from the irrational area ratio of the two fundamental tile shapes, and fine structure due to the long-range quasiperiodic order of the array. By varying the voltage bias of the sample, which governs the rate of vortex diffusion, we can adjust the range of phase coherence in the array and identify the origin of specific features in the magnetoresistance. These ideas have been corroborated by measurements on ladder arrays with varying widths and on periodic arrays with two irrationally-related cell areas. Measurements of the resistive transition and nonlinear current-voltage characteristics are consistent with a Kosterlitz-Thouless vortex-unbinding phase transition at zero field, but show more complicated behavior at finite fields.

Selective interferometric sensing by the use of coherence synthesis

A technique is discussed and demonstrated whereby the sensitivity of an imbalanced fiber-optic interferometric sensor is changed by as much as 70 dB by modifying the power spectrum and thus the coherence function of the input optical source. This phenomenon is then extended and used to monitor selectively single sensors in a small fiber-optic ladder array by synthesizing coherence functions that result in a high sensitivity for the sensor to be observed but a low sensitivity for all the others. Limitations of the demonstrated implementation are discussed and possible future designs presented.

Translational pauses during a spider fibroin synthesis

The large ampullate glands of Nephila clavipes synthesize a tissue-specific fibroin for the web and dragline. Its secretory product migrates as one homogeneous band of approximately 320,000 daltons in denaturing electrophoresis. Similar analyses of the secretory epithelium reveal, in addition to the final product, a step ladder array of peptides in a highly reproducible and consistent pattern. We have correlated these peptide ladders with the process of fibroin synthesis. First, the peptides are very prominent in stimulated glands and quite dim in non stimulated ones. Secondly, by offering the cultured glands different amino acids in the incubating medium, we have linked the presence of the bands with those amino acids which abound in the fibroin. The evidence correlates the peptides with active fibroin synthesis, thus they are products of translation, and possibly reflect discontinuities in the translational process such as those demonstrated during the synthesis of Bombyx fibroin.

Ladder loudspeaker column system

This paper describes some ladder loudspeaker column systems with the following characteristics: (1) Equally spaced ladder loud-speaker column. As a result of the study of several methods to expand the vertical polar response at higher frequencies, it becomes evident that an equally spaced ladder array of the component loud-speakers is the most useful and has the following advantages: (i) A wider vertical polar response at middle and higher frequencies and (ii) easy calculation of directively and simple for construction. (2) Unequally spaced ladder loudspeaker column. Based on the analysis (1) above, the vertical polar response of unequally ladder spaced in arithmetical progression array is investigated. The vertical polar responses of the column with five and seven source elements are calculated. The farfield vertical polar response for five source elements are measured. Both calculations and experiments have shown that the new loudspeaker column system is better than the equally spaced ladder loudspeaker column system in so far as to obtain a wider band directivity at higher frequencies is concerned.

A Note on Impedance and Saturation Power of a Multiple Ladder Array at Millimetre Wavelengths†

ABSTRACT The gain and saturation output power per ladder in a multiple ladder array is significantly greater than that associated with a single ladder circuit. In this note the magnitude of this advantage is estimated under the particular conditions applicable to millimetre tubes. It is concluded that the maximum increase in impedance is 2, the maximum increase in saturation power of the order of 3-4. A number of factors which would tend to reduce this advantage in practice are noted.