The Bipolar Logic of Feedforward and Feedback Circuits

Instead of the conventional 0 and 1 values, bipolar reasoning uses -1, 0, +1 to describe double-sided judgements in which neutral elements are halfway between positive and negative evaluations (e.g., “uncertain” lies between “impossible” and “totally sure”). We discuss the state-of-the-art in bipolar logics and recall two medieval forerunners, i.e., William of Ockham and Nicholas of Autrecourt, who embodied a bipolar mode of thought that is eminently modern. Starting from the trivial observation that “once a wheat sheaf is sealed and tied up, the packed down straws display the same orientation”, we work up a new theory of the bipolar nature of networks, suggesting that orthodromic (i.e., feedforward, bottom-up) projections might be functionally coupled with antidromic (i.e., feedback, top-down) projections via the mathematical apparatus of presheaves/globular sets. When an entrained oscillation such as a neuronal spike propagates from A to B, changes in B might lead to changes in A, providing unexpected antidromic effects. Our account points towards the methodological feasibility of novel neural networks in which message feedback is guaranteed by backpropagation mechanisms endowed in the same feedforward circuits. Bottom-up/top-down transmission at various coarse-grained network levels provides fresh insights in far-flung scientific fields such as object persistence, memory reinforcement, visual recognition, Bayesian inferential circuits and multidimensional activity of the brain. Implying that axonal stimulation by external sources might backpropagate and modify neuronal electric oscillations, our theory also suggests testable previsions concerning the optimal location of transcranial magnetic stimulation’s coils in patients affected by drug-resistant epilepsy.

Design and Analysis of Three-dimensional M-sequence Bipolar OCDMA Spectral Amplitude Code

This paper has been focused to utilize the m-sequence code in spectral/time/spatial OCDMA domain in a bipolar mode (Three Dimensional modes). The scheme has elegantly incorporated the design of an encoder and a decoder such that the system efficiently generates the code in three-dimensional bipolar mode. The decoder design is such that it effectively suppresses the multiple user interference (MUI) of three-dimensional code. System analyses are carried for defining the BER performance variation with users acceptability and received power. The observed results demonstrate that the cardinality of m-sequence three-dimensioanl bipolar code is larger than the existing 3D Pascal code, 2D -MDW,3D -PDC, 2D-PDC, 1D-CWH and 1D-MS codes. The received power in proposed system is -5.8dBm is lesser than the 3D Pascal Code at 10 -18 similarly the users adoption in system more than 210% can be accomplished as compared to 3D Pascal code.

Determining EMC Test Levels for Implantable Devices in Bipolar Lead Configuration

Certain low-frequency magnetic fields cause interference in implantable medical devices. Electromagnetic compatibility (EMC) standards prescribe injecting voltages into a device under evaluation to simplify testing while approximating or simulating real-world exposure situations to low-frequency magnetic fields. The EMC standard ISO 14117:2012, which covers implantable pacemakers and implantable cardioverter defibrillators (ICDs), specifies test levels for the bipolar configuration of sensing leads as being one-tenth of the levels for the unipolar configuration. The committee authoring this standard questioned this testing level difference and its clinical relevance. To evaluate this issue of EMC test levels, we performed both analytical calculations and computational modeling to determine a basis for this difference. Analytical calculations based upon Faraday's law determined the magnetically induced voltage in a 37.6-cm lead. Induced voltages were studied in a bipolar lead configuration with various spacing between a distal tip electrode and a ring electrode. Voltages induced in this bipolar lead configuration were compared with voltages induced in a unipolar lead configuration. Computational modeling of various lead configurations was performed using electromagnetic field simulation software. The two leads that were insulated, except for the distal and proximal tips, were immersed in a saline-conducting media. The leads were parallel and closely spaced to each other along their length. Both analytical calculations and computational modeling support continued use of a one-tenth amplitude reduction for testing pacemakers and ICDs in bipolar mode. The most recent edition of ISO 14117 includes rationale from this study.

Simulation of TiN/HfO2/Pt memristor I–V curve for different conductive filament thickness

The operation of the TiN/HfO2/Pt bipolar memristor has been simulated by the finite elements method using the Maxwell steady state equations as a mathematical basis. The simulation provided knowledge of the effect of conductive filament thickness on the shape of the I–V curve. The conductive filament has been considered as the highly conductive Hf ion enriched HfOx phase (x < 2) whose structure is similar to a Magneli phase. In this work a mechanism has been developed describing the formation, growth and dissolution of the HfOx phase in bipolar mode of memristor operation which provides for oxygen vacancy flux control. The conductive filament has a cylindrical shape with the radius varying within 5–10 nm. An increase in the thickness of the conductive filament leads to an increase in the area of the hysteresis loop of the I–V curve due to an increase in the energy output during memristor operation. A model has been developed which allows quantitative calculations and hence can be used for the design of bipolar memristors and assessment of memristor heat loss during operation.

Treatment of Marigold Flower Processing Wastewater Using a Sequential Biological- Electrochemical Process

Agriculture is the mainstay of the Indian economy. The agro-based industries produce high volumes of highstrength wastewaters that need to be treated and reused to prevent environmental pollution and water wastage. This study evaluated the performances of a sequential biological-electrochemical process for treating an anaerobically digested effluent of a Marigold flower processing agro-industry. The uniqueness of this wastewater possess a major challenge to its treatment since not many studies have been conducted on this wastewater. The biological treatment was carried out in a Sequential Batch Reactor (SBR). The treated water was further polished in a Continuous Bipolar-mode Electrochemical Reactor (ECR) to remove the residual organics. The anaerobically digested effluent Chemical Oxygen Demand (COD), Dissolved Organic Carbon (DOC), Total Nitrogen (TN), Total Phosphorus (TP) and Total Suspended Solids (TSS) were 5750 ± 991 mg/L, 980 ± 120 mg/L, 692 ± 60 mg/L, 9.7 ± 1.1 mg/L, and 1144 ± 166 mg/L, respectively. A significant level of treatment was achieved in the SBR. The combined system was able to remove 79% of COD, 85% of DOC, 53% of TN, and almost 100% of TP, TSS, and Volatile Suspended Solids (VSS). Several organic compounds belonging to the category of natural plants compound, pesticide, fungicide, etc. were detected in the raw wastewater. Most of the compounds were almost completely removed by the treatment system. The final effluent was almost colorless and free from suspended solids. However, for reuse, the water needs to be further treated in an advanced oxidation process.

Comparison of radiofrequency ablation processes for monopolar and bipolar systems

Most of the manufactured radiofrequency ablation devices use single electrodes inserted into the tumor for heating. In order to increase the volume of heating, they are cooled from the inside, and some have a system for wetting the outer surface of the electrode with saline. The need for necrosis of tumors with a diameter of more than 3 cm made us look for other design solutions that would significantly increase the volume of heated tissue. At the beginning, these were attempts to increase the number of heat sources inside the tumor by opening additional wires in the tumor, then the transition began to increase the number of electrodes to three and increase the number of working zones on each electrode. As a result, heating volumes of 90 cm3 were achieved with a heating time of 45 min. A study of the scientific and technical literature on RFA showed that foreign firms producing ablation devices already understand the need to replace monopolar electrodes with bipolar multi-electrode devices. The reason for this is not only the better postoperative characteristics of the use of bipolar electrodes, but also the emergence, in addition to oncology, of new areas of ablation application, where more complex forms of thermal fields are used during therapy, for example, tubular zones of necrosis. A radical solution to the problem of increasing the volume of coagulation is the transition from monopolar single electrodes to bipolar multielectrode designs. In this case, the electric field is concentrated in the areas between the electrodes and the heating efficiency increases significantly throughout the tumor volume, including the peripheral part. The most effective way is to incorporate bipolar electrodes into a circular cluster, allowing all electrodes to work simultaneously. Under the control of an ultrasound scanner, 4 to 12 electrodes are inserted, operating in bipolar mode. A model has been developed and the design of a four-electrode cluster has been developed, which allows for distributed heating of the tumor in a bipolar mode. As a result of the studies carried out, it was found that the use of bipolar systems allows: to significantly increase the volume of the area of necrosis due to the possibility of increasing the power supplied to the tumor; to reduce the unevenness of heating over the volume of the tumor by obtaining temperature fields, the shape of which is closest to the required one; improve patient survival rates by placing electrodes outside the tumor (“NO TOUCH” mode). The work performed indicates the technical possibility of a significant increase in the volume of destroyed tissue by increasing the number of electrodes and placing electrodes along the tumor volume closer to the periphery, including the ablastic zone. As a result, it became possible to heat tumors from their periphery without contacting the electrodes with the tumor. The increase in the number of heat sources made it possible not only to reduce the load on the electrodes, but also to shorten the procedure time. Ablation of large volumes entailed an inevitable increase in the number of electrodes in a multi-electrode system, which led to the complication of their connection to the generator. So far, an unresolved problem remains to reduce the total impedance of the generator load.

Switching Monopolar Mode for RF-Assisted Resection and Superficial Ablation of Biological Tissue: Computational Modeling and Ex Vivo Experiments

Radiofrequency (RF)-based monopolar (MM) and bipolar mode (BM) applicators are used to thermally create coagulation zones (CZs) in biological tissues with the aim of destroying surface tumors and minimizing blood losses in surgical resection. Both modes have disadvantages as regards safely and in obtaining a sufficiently deep coagulation zone (CZ). In this study, we compared both modes versus a switching monopolar mode (SMM) in which the role of the active electrode changes intermittently between the two electrodes of the applicator. In terms of clinical impact, the three modes can easily be selected by the surgeon according to the surgical maneuver. We used computational and experimental models to study the feasibility of working in MM, BM, and SMM and to compare their CZ characteristics. We focused exclusively on BM and SMM, since MM only creates small coagulation zones in the area between the electrodes. The results showed that SMM produces the deepest CZ between both electrodes (33% more than BM) and SMM did not stop the generator when an electrode lost contact with the tissue, as occurred in BM. Our findings suggest that the selective use of SMM and BM with a bipolar applicator offers greater advantages than using each type alone.