arXiv subjects

Mehdi Fardmanesh

Publications and source records attributed to Mehdi Fardmanesh.

At least 19 recordsLinked to original sources

arXiv2025

Effect of Dopamine in Enhancement of SNR of Cortico-Striatal-Thalamo-Cortical Loop Spiking

In this work, the effects of dopamine neurotransmitter within the Cortico-Striatal-Thalamo-Cortical (CSTC) loop have been investigated. Simulations confirmed dopamine facilitates movement via thalamic disinhibition. Analysis of its impact on the signal-to-noise ratio (SNR) revealed a complex, region-specific outcome: SNR increased in some regions (e.g., D2 Striatum: 3.41 dB to 6.25 dB), decreased in others (e.g., Thalamus VL: 6.24 dB to 3.93 dB), and remained stable elsewhere (e.g., M1: 3.16 dB to 3.13 dB). This heterogeneity stems from dopamine increasing the excitability of D1-receptor-expressing neurons, which amplifies channel conductance noise and reduces SNR in specific circuits. Thus, dopamine acts not as a uniform signal enhancer, but as a complex modulator that critically balances facilitation and noise within the CSTC loop.

q-bio.NC↗

arXiv2025

Optimization of Argon Plasma Working Pressure through Parallel PIC Simulations for Enhancement of Material Surface Treatment

In this study, a novel method for simulating plasma dynamics using parallel programming has been developed. The equations based on Particle-in-Cell (PIC) method were utilized and adapted for this purpose. We utilized 35 processors from Sharif High Performance Computing (HPC) center and divided the plasma volume into 35 parts, with each part's PIC equation solved on a separate processor. Once the computations were completed, the results from all processors were combined to form a complete plasma volume. The simulations revealed that there is an optimal pressure for argon, at which the ion flux onto the electrode surface is maximized. Increasing the absolute value of the electrode potential also increases this flux. Therefore, for a given potential, selecting the optimal pressure is crucial for the most effective surface modification using argon plasma. In this work, for applied voltage of -500 V, the optimum pressure was 100 mTorr.

physics.plasm-ph↗

arXiv2025

A novel cost-effective fabrication of a flexible neural probe for brain signal recording

This study introduces a novel, flexible, and implantable neural probe using a cost-effective microfabrication process based on a thin polyimide film. Polyimide film, known as Kapton, serves as a flexible substrate for microelectrodes, conductive tracks, and contact pads of the probe, which are made from a thin film of gold (Au). SU-8 is used to cover the corresponding tracks for electrical isolation and to increase the stiffness of the probe for better implantation. To evaluate the performance of the fabricated probe, electrochemical impedance spectroscopy (EIS) and artificial neural signal recording have been used to characterize its properties. The microelectrode dimensions have been carefully chosen to provide low impedance characteristics, which are necessary for acquiring local field potential (LFP) signals. The in vivo LFP data have been obtained from a male zebra finch presented with auditory stimuli. By properly filtering the extracellular recordings and analyzing the data, the obtained results have been validated by comparing them with the signals acquired with a commercial neural electrode. Due to the use of Kapton, SU-8, and Au materials with non-toxic and adaptable properties in the body environment, the fabricated neural probe is considered a promising biocompatible implantable neural probe that may pave the way for the fabrication of other neural implantable devices with commercial aims.

q-bio.NC↗

arXiv2025

Analyzing Blood Glucose Levels with Near Infra-Red Spectroscopy and Chemometric Multivariate Methods

In this work, the blood NIR absorbances are recorded using the FT-IR method. It is shown that when the absorbance curves are multiplied by the first derivative of the water absorbance spectrum as well as by the first derivative of the glucose absorbance, the peaks related to the water interferent in the blood are effectively removed from the blood absorbance spectra, allowing for better distinction of the peaks of the blood glucose. The PCR prediction using this method shows smaller errors compared to the PCR employing the net absorbances, while the number of derived principal components is smaller in the PCR method based on the derivatives than the one based on the net absorbances. Additionally, the prediction of blood glucose levels using a linear regression model based on the molar absorptivity of glucose also demonstrates acceptable accuracy.

physics.med-ph↗

arXiv2025

Protected Symmetrical Superconducting Qubit Based on Quantum Flux Parametron

Conventional Quantum Flux Parametrons (QFPs) have historically been used for storing classical bits in Josephson junction-based computers. In this work, we propose a novel QFP-based topology dubbed "Degenerium" qubit, to process and compute quantum information. Degenerium combines principles from the 0-$\pi$ qubit and flux qubit to create ideally degenerate quantum ground states, while significantly simplifying the 0-$\pi$ qubit structure. The symmetrical design of Degenerium enables easier qubit control and fabrication. We demonstrate that due to the inherent symmetry of Degenerium, our designed qubit is insensitive to fabrication-induced variations in critical current ($I_c$) of the Josephson junctions. Our calculations of depolarization and dephasing rates due to charge, flux, and critical current noise sources result in depolarization and dephasing times of 1.25 s and 90 $\mu$s, respectively. Further parameter tuning and optimization is possible to meet specific application demands.

cond-mat.supr-con↗

arXiv2024

Derivative-Based Mir Spectroscopy for Blood Glucose Estimation Using Pca-Driven Regression Models

In this study, we presented two innovative methods, which are Threshold-Based Derivative (TBD) and Adaptive Derivative Peak Detection(ADPD), that enhance the accuracy of Learning models for blood glucose estimation using Mid-Infrared (MIR) spectroscopy. In these presented methods, we have enhanced the model's accuracy by integrating absorbance data and its differentiation with critical points. Blood samples were characterized with Fourier Transform Infrared (FTIR) spectroscopy and advanced preprocessing steps. The learning models were Ridge Regression and Support Vector Regression(SVR) using Leave-One-out Cross-Validation. Results exhibited that TBD and ADPD significantly outperform basic used methods. For SVR, the TBD increased the r2 score by around 27%, and ADPD increased it by around 10%. these Ridge Regression values were between 36% and 24%. In addition, Results demonstrate that TBD and ADPD significantly outperform conventional methods, achieving lower error rates and improved clinical accuracy, validated through Clarke and Parkes Error Grid Analysis.

eess.IV↗

arXiv2022

Frequency Response Analysis of Backside Illuminated Free-Membrane Type IR Superconducting Bolometer

The IR response of a backside illuminated type Yttrium Barium Copper Oxide (YBCO) transition-edge bolometer (TEB) in a free-membrane configuration is measured and analyzed. The analysis is based on a comprehensive equivalent circuit model for the bolometer structure considering all the thermal parameters of the device. The detector is made using a 450nm superconductive YBCO thin film grown on about 100 um thick crystalline SrTiO3 (STO) substrate using an optimized low cost Metal Organic Deposition (MOD) technique. The backside illuminated structure provided a basis for freely utilizing different IR absorber materials and structures on the backside of the bolometer in order to get wide band high radiation absorption coefficient for the device, while also avoiding any negative effect of the deposition of the absorber layer on the YBCO thin film properties. The obtained analytical and experimental results for the backside illuminated bolometer were also compared with the results of the previously reported front-side illuminated bolometers.

cond-mat.supr-con↗

arXiv2022

Warp and Weft Wiring method for rapid, modifiable, self-aligned, and bonding-free fabrication of multi electrodes microfluidic sensors

The need for rapid fabrication of microfluidic devices has become increasingly critical as microfluidics become part of biomedical sensors. Using Warp and Weft Wiring (WWW) of copper wires, this paper presents a novel low-cost method for rapid, self-aligned, bonding-free, and modifiable fabrication of multi-electrodes microfluidic sensors. All the proposed features are promising and highly recommended for the development of Point-of-Care Tests (POCTs), while most of the conventional methods have low chances of coming out of the research labs and play no role in POCTs development. To have an experimental proof of concept, the proposed chip was fabricated and then tested with two sets of experiments that showed the potential applications of water quality management, hygiene, biomedical impedance measurement, cell analysis, flow cytometry, etc.

q-bio.QM↗

arXiv2022

Physics-Data Driven Machine Learning Based Model: A Hybrid Way for Nonlinear, Dynamic, and Open-loop Identification of IPMC Soft Artificial Muscles

Ionic Polymer Metal Composites (IPMCs) are one of the most preferred choices among biocompatible materials for industrial and biomedical applications. Despite their advantages, some of their drawbacks include non-linear and hysteretic behavior, which complicates the modeling process. In previous works, usually autoregressive models were used to predict the behavior of an IPMC actuator. The main drawback of using an autoregressive model is that it cannot be used in mobile and real-time applications. In this study, we proposed a hybrid analytical intelligent model for an IPMC actuator. The most outstanding feature of this model is its non-autoregressive structure. The hybrid concept proposed in this study can be generalized to various problems other than IPMCs. The structure used in this work comprises an analytical model and a deep neural network, providing a non-linear, dynamic, and non-autoregressive model for the IPMC actuator. Lastly, the average NMSE achieved using the proposed hybrid model is 9.5781e-04 showing a significant drop in the error rate compared to other non-autoregressive structures.

cs.LG↗

arXiv2021

Demonstration of Thermal Images Captured by a Backside Illuminated Transition Edge Bolometer

A high temperature superconducting detector was fabricated to capture the thermal images in room temperature background. The detector was made of YBa2Cu3O7-δ (YBCO) superconducting thin film deposited on an Yttria Stabilized Zirconia (YSZ) substrate, structurally modified for high responsivity performance. A very thin absorber layer was implemented on the backside of the detector to increase the absorption of the device at infrared (IR) range of frequencies. To capture thermal images, a movable off-axis parabolic mirror on XY plane was used for focusing the incoming IR radiation including the thermal signal of the objects onto the device surface. The captured thermal images belong to the objects within the temperature range between 300K and 400K, which correspond to our imaging optics.

physics.ins-det↗

arXiv2021

A novel fully 3D, microfluidic-oriented, gel-based and low cost stretchable soft sensor

In this paper, a novel fully 3D, microfluidic-oriented, gel-based, and low-cost highly stretchable resistive sensors have been presented. By the proposed method we are able to measure and discriminate all of the stretch, twist, and pressure features by a single sensor which is the potential that we have obtained from the fully 3D structure of our sensor. Against previous sensors which all have used EGaIn as the conductive material of their sensor, we have used low-cost, safe, and ubiquitous glycol-based gel instead. To show the functionality of the proposed sensor some FEM simulations, a set of the designed experimental tests were done which showed the linear, accurate, and durable operation of the proposed sensor. Finally, the sensor was put through its paces on the knee, elbow, and wrist of a female test subject. Also, to evaluate the pressure functionality of the sensor, a fully 3D active foot insole was developed, fabricated, and evaluated. All of the results show promising features for the proposed sensor to be used in real-world applications like rehabilitation, wearable devices, soft robotics, smart clothing, gait analysis, AR/VR, etc.

q-bio.QM↗

arXiv2021

Toward a High Performance IPMC Soft Actuator using A disturbance-aided method

Besides the advantages of Ionic polymer-metal composites (IPMCs) for biomedical applications, there are some drawbacks in their performance, which can be enhanced. One of those critical drawbacks is "back relaxation" (BR). If we apply a step voltage to IPMC, it will bend in the anode direction. Afterward, there is an unwanted and relatively slow counter-bending toward the cathode side. There are some disadvantages in the current BR control methods of IPMC actuators that prevent them from being used in real applications. This paper presents a new non-feedback method for eliminating the BR effect of non-patterned IPMCs by using a relatively high-frequency disturbance and proving it by theoretical and experimental explanations. The results show that the proposed method, needless to have any pattern on the electrodes of the IPMCs, can significantly eliminate the BR effect. Unlike the patterned IPMCs, no reduction will occur in the bending amplitude of IPMC, and even we can see the increased bending amplitude.

cond-mat.soft↗

arXiv2020

A wide band low profile linear cross polarizer for millimeter wave applications

In this article, two wide band high-efficiency metasurface structures as a linear-cross polarizer in transmission mode based on asymmetric split-ring resonators (ASRR) are proposed and tested to indicate that this is not a purely theoretical work. A unit cell of the first structure consists of double polarization-sensitive S-shape resonators (SRs) on the bottom side of the dielectric layer. The superiority of this proposed structure is its filtering property and high conversion efficiency at its resonant frequency, 100 GHz, where its cross-polarized transmission coefficient reaches 0.87. The simulation results show that the polarization conversion ratio (PCR) exceeds 85% in the frequency range of 86 to 139 GHz. Additionally, the second structure consistsed of a wire-grid array as the bottom layer. This structure has extremely low co-polarized transmission amplitude which represents a good polarization transformer in cross-direction. Furthermore, this structure has a polarization conversion ration more than 95% in frequency range of 50 to 200GHz, having wider relative bandwidth compared to the first proposed polarizer. The performance of both polarizers has very weak angular dependence under the oblique incident of x-polarized EM wave with from to .A prototype of these proposed polarizers has been fabricated and a good agreement between experimental and simulation results has been observed. These proposed structures can find application in mm-wave and THz sensing and imaging systems which benefit from polarimetric measurements.

physics.optics↗

arXiv2019

Design and Fabrication of an Ultra-low Noise Ag-AgCl Electrode

We have developed a new method for fabrication of ultra-low noise silver-silver chloride (Ag-AgCl) reference electrode with dramatically high stability, useful in biomedical precise measurements. Low noise level and high stability are the most important features when evaluating reference electrode for example when used as a half-cell at electrochemical cells. The noise was measured for bare Ag-AgCl electrode pairs in a saline electrolyte without any junction. The noise spectral density for such measurements increases at low frequencies due to flicker (1/f) noise. Thermal noise from the real part of the electrode impedance is always lower than 1/f noise and is shown as offset voltage in noise spectrum. Electrode noise is highly correlated to its offset voltage. Moreover, the variance of the potential difference in our measurements is correlated to the noise level of electrodes. In this paper, offset voltage spectrum and the variance of data while doing measurements are proposed for identification of noise in our electrodes. The results presented suggest a new process for fabrication of electrode pairs with differential noise potential of 16 nanovolt root mean square at frequency of 1 Hz.

physics.chem-ph↗

arXiv2018

Blood Glucose Measurement Based on Infra-Red Spectroscopy

An algorithm based on PLS regression has been developed and optimized for measuring blood glucose level using the infra-red transmission spectrum of blood samples. A set of blood samples were tagged with their glucose concentration using an accurate invasive glucometer and analyzed using a standard FTIR spectrometer. Using the developed algorithm, the results of the FTIR spectroscopy of the samples were analyzed to find the glucose concentration in the samples. The obtained glucose concentration by the algorithm were in good agreement with the results obtained by the standard glucometer, and the mean estimation error was 7 mg/dL. This error is in the range of available commercial invasive meters.

q-bio.QM↗

arXiv2017

HTS YBCO Resonator Configuration with Coplanar Optimized Flux Concentrator Strongly Coupled to rf SQUID

We developed a novel magnetic coupling module formed of a monolayer superconducting flux concentrator, which is integrated with a coplanar resonator strongly coupled to HTS rf-SQUID. Three types of resonators, including a long stripline resonator between input loop and pick-up loop of the flux concentrator, a complementary split ring resonator (CSRR), and also a spiral shape inside the input loop are explored. The resonance quality factors as well as the coupling to the SQUID of different patterns of these three types of the resonators is evaluated using Finite Element Method (FEM) simulations. Several readout methods to couple the electronic system to the resonators are tested, including inductive (coil) and capacitive (transmission line) couplings, and the optimum readout is reported for each of the resonators. Among the evaluated resonator types, a spiral shape resonator with optimal design showing the highest quality factor (5900) together with the strongest coupling to the SQUID (-0.5 dB) at resonance frequency of 836 MHz, is fabricated using 200 nm thick superconducting YBCO on a 1 mm thick crystalline LaAlO3 substrate. The flux concentrator of the module is optimized by the variation of its linewidths and also its input loop radius to obtain maximum flux transformation efficiency.

physics.ins-det↗

arXiv2014

Precise Time Evolution of Superconductive Phase Qubits

New procedure on precise analysis of superconducting phase qubits using the concept of Feynman path integral in quantum mechanics and quantum field theory has been introduced. The wave function and imaginary part of the energy of the pseudo ground state of the Hamiltonian in phase qubits has been obtained from semi classical approximation and we we estimate decay rate, and thus the life time of meta stable using the approach of Instanton model. We devote the main effort to study the evolution of spectrum of Hamiltonian in time after addition of interaction Hamiltonian, in order to obtain the high fidelity quantum gates.

cond-mat.supr-con↗

arXiv2014

Fate of False Vacuum in Superconducting Flux Qubits

We propose a similarity between the scenario of fate of false vacuum in cosmology at early universe and the situation in where the quantum state decays in superconducting Flux qubit. This is due to the fact that both cases have two homogeneous stable equilibrium states in scalar field, which in quantum theory, could penetrate through the barrier in different possibilities and hence considered unstable decaying in time. In quantum computation, decay rate is among the most important factors in characteristics of the system like coherency, reliability, measurement fidelity, etc. In this considered potential, the decay rate from the penetrating (False vacuum) state to the stable (absolute minimum) state is achieved to leading order in Planck constant by the approach of Instanton model. In case of the superconducting flux qubit having thin barrier potential, the decay rate is calculated and its relations with actual set of parameters in flux qubit design are introduced.

cond-mat.supr-con↗