Satyajit Sahu

Multi-level memory-switching properties of a single brain microtubule

We demonstrate that a single brain-neuron-extracted microtubule is a memory-switching element, whose hysteresis loss is nearly zero. Our study shows how a memory-state forms in the nanowire and how its protein arrangement symmetry is related to the conducting-state written in the device, thus, enabling it to store and process ∼500 distinct bits, with 2 pA resolution between 1 nA and 1 pA. Its random access memory is an analogue of flash memory switch used in a computer chip. Using scanning tunneling microscope imaging, we demonstrate how single proteins behave inside the nanowire when this 3.5 billion years old nanowire processes memory-bits.

Atomic water channel controlling remarkable properties of a single brain microtubule: Correlating single protein to its supramolecular assembly

Microtubule nanotubes are found in every living eukaryotic cells; these are formed by reversible polymerization of the tubulin protein, and their hollow fibers are filled with uniquely arranged water molecules. Here we measure single tubulin molecule and single brain-neuron extracted microtubule nanowire with and without water channel inside to unravel their unique electronic and optical properties for the first time. We demonstrate that the energy levels of a single tubulin protein and single microtubule made of 40,000 tubulin dimers are identical unlike conventional materials. Moreover, the transmitted ac power and the transient fluorescence decay (single photon count) are independent of the microtubule length. Even more remarkable is the fact that the microtubule nanowire is more conducting than a single protein molecule that constitutes the nanowire. Microtubules vibrational peaks condense to a single mode that controls the emergence of size independent electronic/optical properties, and automated noise alleviation, which disappear when the atomic water core is released from the inner cylinder. We have carried out several tricky state-of-the-art experiments and identified the electromagnetic resonance peaks of single microtubule reliably. The resonant vibrations established that the condensation of energy levels and periodic oscillation of unique energy fringes on the microtubule surface, emerge as the atomic water core resonantly integrates all proteins around it such that the nanotube irrespective of its size functions like a single protein molecule. Thus, a monomolecular water channel residing inside the protein-cylinder displays an unprecedented control in governing the tantalizing electronic and optical properties of microtubule.

Tuning of nonvolatile bipolar memristive switching in Co(III) polymer with an extended azo aromatic ligand.

We have fabricated a unique memristive device by molecular engineering and demonstrated that the leakage current tuning in the device is 100 times more efficient than that in a standard device. Molecular analogs of the memristive matrices used here are an electrochemically active conjugated Co(III) polymer (CP) and a nonconjugated Co(III) polymer (NCP), which have been synthesized in good yield and characterized by (1)H NMR spectroscopy. Redox switching of an organic-metallic hybrid polymer generates bistable states with a large ON/OFF ratio that supports random flip-flops for several hours. Thus, we provide a synthetic solution to leakage current restriction, one of the fundamental problems faced when fabricating state-of-the-art electronic devices.

Massively parallel computing on an organic molecular layer

Modern computers operate at enormous speeds—capable of executing in excess of 1013 instructions per second—but their sequential approach to processing, by which logical operations are performed one after another, has remained unchanged since the 1950s. In contrast, although individual neurons of the human brain fire at around just 103 times per second, the simultaneous collective action of millions of neurons enables them to complete certain tasks more efficiently than even the fastest supercomputer. Here we demonstrate an assembly of molecular switches that simultaneously interact to perform a variety of computational tasks including conventional digital logic, calculating Voronoi diagrams, and simulating natural phenomena such as heat diffusion and cancer growth. As well as representing a conceptual shift from serial-processing with static architectures, our parallel, dynamically reconfigurable approach could provide a means to solve otherwise intractable computational problems. The processors of most computers work in series, performing one instruction at a time. This limits their ability to perform certain types of tasks in a reasonable period. An approach based on arrays of simultaneously interacting molecular switches could enable previously intractable computational problems to be solved.

Live visualizations of single isolated tubulin protein self-assembly via tunneling current: effect of electromagnetic pumping during spontaneous growth of microtubule

As we bring tubulin protein molecules one by one into the vicinity, they self-assemble and entire event we capture live via quantum tunneling. We observe how these molecules form a linear chain and then chains self-assemble into 2D sheet, an essential for microtubule, —fundamental nano-tube in a cellular life form. Even without using GTP, or any chemical reaction, but applying particular ac signal using specially designed antenna around atomic sharp tip we could carry out the self-assembly, however, if there is no electromagnetic pumping, no self-assembly is observed. In order to verify this atomic scale observation, we have built an artificial cell-like environment with nano-scale engineering and repeated spontaneous growth of tubulin protein to its complex with and without electromagnetic signal. We used 64 combinations of plant, animal and fungi tubulins and several doping molecules used as drug, and repeatedly observed that the long reported common frequency region where protein folds mechanically and its structures vibrate electromagnetically. Under pumping, the growth process exhibits a unique organized behavior unprecedented otherwise. Thus, “common frequency point” is proposed as a tool to regulate protein complex related diseases in the future.

Layer-by-layer assembly of capped CdSe nanoparticles: Electrical bistability and memory phenomenon

The authors demonstrate thin-film formation of capped-CdSe nanoparticles via layer-by-layer electrostatic assembly. The assembly of two types of nanoparticles in sequence—with anionic and cationic capping agents, respectively—results in thin films of CdSe nanoparticles. Devices based on such thin films demonstrate electrical bistability. The bistability, which is reversible in nature, is due to charge confinement in the nanoparticles and has an associated memory phenomenon. The devices based on the CdSe nanoparticles exhibit high on/off ratio and demonstrate read-only and random-access memory applications.

Design and Construction of a Brain-Like Computer: A New Class of Frequency-Fractal Computing Using Wireless Communication in a Supramolecular Organic, Inorganic System

Here, we introduce a new class of computer which does not use any circuit or logic gate. In fact, no program needs to be written: it learns by itself and writes its own program to solve a problem. Godel’s incompleteness argument is explored here to devise an engine where an astronomically large number of “if-then” arguments are allowed to grow by self-assembly, based on the basic set of arguments written in the system, thus, we explore the beyond Turing path of computing but following a fundamentally different route adopted in the last half-a-century old non-Turing adventures. Our hardware is a multilayered seed structure. If we open the largest seed, which is the final hardware, we find several computing seed structures inside, if we take any of them and open, there are several computing seeds inside. We design and synthesize the smallest seed, the entire multilayered architecture grows by itself. The electromagnetic resonance band of each seed looks similar, but the seeds of any layer shares a common region in its resonance band with inner and upper layer, hence a chain of resonance bands is formed (frequency fractal) connecting the smallest to the largest seed (hence the name invincible rhythm or Ajeya Chhandam in Sanskrit). The computer solves intractable pattern search (Clique) problem without searching, since the right pattern written in it spontaneously replies back to the questioner. To learn, the hardware filters any kind of sensory input image into several layers of images, each containing basic geometric polygons (fractal decomposition), and builds a network among all layers, multi-sensory images are connected in all possible ways to generate “if” and “then” argument. Several such arguments and decisions (phase transition from “if” to “then”) self-assemble and form the two giant columns of arguments and rules of phase transition. Any input question is converted into a pattern as noted above, and these two astronomically large columns project a solution. The driving principle of computing is synchronization and de-synchronization of network paths, the system drives towards highest density of coupled arguments for maximum matching. Memory is located at all layers of the hardware. Learning, computing occurs everywhere simultaneously. Since resonance chain connects all computing seeds, wireless processing is feasible without a screening effect. The computing power is increased by maximizing the density of resonance states and bandwidth of the resonance chain together. We discovered this remarkable computing while studying the human brain, so we present a new model of the human brain in terms of an experimentally determined resonance chain with bandwidth 10−15 Hz (complete brain with all sensors) to 10+15 Hz (DNA) along with its implementation using a pure organic synthesis of entire computer (brain jelly) in our lab, software prototype as proof of concept and finally a new fourth circuit element (Hinductor) based beyond Complementary metal-oxide semiconductor (CMOS) hardware is also presented.

Evidence of massive global synchronization and the consciousness: comment on "Consciousness in the universe: a review of the 'Orch OR' theory" by Hameroff and Penrose.

The blind faith that Hodgkin–Huxley type neuron bursts explain the neural information processing completely would collapse soon, and then the brain building projects [1] all over the world will face the danger of banking on an incomplete picture of a neuron. In the last decade, a series of discoveries were made in the logical processing of arguments in the thousands of dendritic and synaptic channels [2–6], which are mathematically massively complex computations. One input and one output type Hodgkin–Huxley neuron bursts neglect every part of meticulously designed local logical processes and lead us to an absolute simplistic world, which brain builders manipulate further to fit their needs. Ample arguments would trigger the collapse of HH model [7] and the vacuum created thereafter needs to find a material inside the neuron that would give rise to the synchronous firing of neurons and consequent computations. The recent finding of microtubule’s resonant oscillation [8,9] that could vibrate axon brings Orch-OR into the picture as an extremely essential concept to fill the vacuum. Hameroff and Penrose have rightly argued here [10] that the wireless communication of axons via resonant vibrations around a hundred micrometers diameter domain alleviates the biggest criticism of the Orch-OR proposal. The orchestration of resonant vibrations can occur globally between all neurons across the entire brain. For that communication, an axon inside a neuron does not require sending incredibly powerful signal wirelessly throughout the brain, by crossing the fatty myelin sheath. Conical radiation/absorption only in its vicinity via dual polar ends of a neuron would be enough to trigger a cascade communication globally throughout the entire brain. This article therefore closes the series of historical argument/counterargument on the “gap junction” forever [11]. The entire episode of objective reduction also gets a new dimension because resonance frequency bands of brain materials cover a wide range. Inverse of frequency is time, so we have now the experimental evidence of multiple clocks, each for a resonance band. Thus, transition of information or signal from one clock-world to another consolidates the imaginary time concept [12]. In addition, the fractal shape of entire brain architecture suggests that one clock is physically located inside another clock. Hence, we get information processing in an imaginary space. When we have both an imaginary space and an imaginary time, then we get a generalized hyperdimension space. Therefore, the discovery of resonance and wireless processing lead to a layered architecture of multiple space–time metric stacked one

Electrical bistability in a xanthene class molecule : Conduction mechanisms

The author study conduction mechanism in two conducting states of a bistable device at 10–300K range. They find that in the electrical bistable devices, electrical switching is associated with a change in the conduction mechanism. Device current in the low-conducting state follows an injection-limited mechanism. The current in the high-conducting state conforms a bulk-dominated mechanism, namely, space-charge limited conduction with an exponential distribution of traps. The bistability has an associated memory phenomenon. The devices exhibit read-only and random-access memory applications for several hours.

Molecular implementations of cellular automata

Cellular Automata (CA) have a long history as computation models, but only in the last few years have serious attempts started to implement them in terms of molecules. Such nano-technological innovations promise very cost-effective fabrication because of the regular structure of CA, which allows assembly through molecular self-organization. The small sizes of molecules combined with their availability in Avogadroscale numbers promises a huge computational power, in which the massive parallelism inherent in CA can be effectively exploited. This paper discusses critical background aspects of our recent results on the implementation of a CA by a molecular assembly (Bandyopadhyay et al., Nature Physics 2010).