Whiting James G H, de Lacy Costello Ben P J, Adamatzky Andrew
International Centre of Unconventional Computing, University of the West of England, Bristol, BS16 1QY, UK.
International Centre of Unconventional Computing, University of the West of England, Bristol, BS16 1QY, UK; Institute of Biosensor Technology, University of the West of England, Coldharbour Lane, Bristol, BS16 1QY, UK.
Biosystems. 2015 Feb;128:48-51. doi: 10.1016/j.biosystems.2015.01.009. Epub 2015 Jan 27.
The slime mould Physarum polycephalum is a large single celled myxomycete; its plasmodium consists of tubes which extend to find sources of food. It has been previously shown that the tubes are conductive with a resistance of approximately 3 MΩ, and have been used in basic DC circuits. Hybrid slime mould-electronic circuits have been proposed, using the protoplasmic tubes, grown between agar, as Physarum wires. This paper aims to evaluate the electrical properties of the protoplasmic tubes with respect to analogue and digital waveforms. The Physarum wires act as low pass filters with a mean cut off frequency of 19kHz (SD 9 KHz); they have a 12.1 dB/decade roll-off (SD 1.9 dB/decade). Mean attenuation across the band-pass range is -6 dB (S.D. 4.5 dB). The mechanism for the frequency dependant attenuation is unknown however a combination of protoplasmic electrolyte and the cytoskeletal structure is the most likely cause. The tubes last approximately 2 weeks before forming a dry sclerotia, when they cease being conductive and is the prevalent limiting factor of their practical use; this is caused by dehydration and lack of nutrition, a limitation which may be overcome. The potential for Physarum wires in hybrid circuits is strengthened; while previous circuits were simple DC circuits, this work demonstrates that they may be used as electronic components or wires in both digital and analogue circuits or even as a computing component in analogue computers.
多头绒泡菌是一种大型单细胞黏菌；其原质团由延伸以寻找食物来源的管子组成。先前已表明这些管子具有导电性，电阻约为3兆欧，并已用于基本直流电路。有人提出了混合黏菌 - 电子电路，利用在琼脂之间生长的原生质管作为黏菌导线。本文旨在评估原生质管在模拟和数字波形方面的电学特性。黏菌导线充当低通滤波器，平均截止频率为19千赫（标准差9千赫）；它们具有12.1分贝/十倍频程的滚降（标准差1.9分贝/十倍频程）。带通范围内的平均衰减为 -6分贝（标准差4.5分贝）。然而，频率依赖性衰减的机制尚不清楚，不过原生质电解质和细胞骨架结构的组合是最可能的原因。这些管子在形成干燥菌核之前大约能持续2周，此时它们停止导电，这是其实际应用中普遍存在的限制因素；这是由脱水和营养缺乏导致的，这种限制可能会被克服。黏菌导线在混合电路中的潜力得到了增强；虽然以前的电路是简单的直流电路，但这项工作表明它们可在数字和模拟电路中用作电子元件或导线，甚至可在模拟计算机中用作计算元件。
