Millivolt Range Research Articles

Stable Millivolt Range Resistive Switching in Percolating Molybdenum Nanoparticle Networks.

To overcome the limitations of the conventional Von Neumann architecture, inspiration from the mammalian brain has led to the development of nanoscale neuromorphic networks. In the present research, molybdenum nanoparticles (NPs), which were produced by means of gas phase condensation based on magnetron sputtering, are shown to be the constituents of electrically percolating networks that exhibit stable, complex, neuron-like spiking behavior at low potentials in the millivolt range, satisfying well the requirement of low energy consumption. Characterization of the NPs using both scanning electron microscopy and scanning transmission electron microscopy revealed not only pristine shape, size, and density control of Mo NPs but also a preliminary proof of the working mechanism behind the spiking behavior due to filament formations. Furthermore, electrostatics COMSOL Multiphysics simulations of the morphology of the NPs provided evidence that the stable switching is due to the as-deposited stellate Mo NPs creating high electric field strengths, while keeping them separated, not seen before in other percolating networks based on spherical NPs. Hence, our results show the working mechanism behind switching in percolating Mo NP networks and show that they are very promising for realistic neuromorphic systems.

Nanoporous Dna Field Effect Transistor with Potential for Random‐Access Memory Applications: A Selectivity Performance Evaluation

AbstractMethods to encode digital data items as strands of synthetic DNA followed by selective data retrieval have been demonstrated. However, these initially bio‐oriented processes remain slow and not optimized. DNA field‐effect transistor (DNA‐FET) is studied here as a possible random‐access memory (RAM) device for simple, selective and rapid ssDNA fragment retrieval used as data pool identifier. The DNA‐FET is based on a co‐planar Au‐gated fully organic transistor appended with short single‐stranded DNA (ssDNA) probes bearing a blocking molecule to prevent partial hybridization and achieve near perfect selectivity for short length ssDNA (up to 45 nt). Examination of transconductance of the novel active layer incorporating a DNA nanopore architecture reveals enhanced binding site accessibility. This, in turn, facilitates discriminatory hybridization, particularly in the physical retrieval of short‐length ssDNA from a competitive, concentrated ssDNA background pool consisting of nine different sequences, with at least one nucleotide difference. The DNA‐FET exhibits rapid operation (9 min) in the millivolt range, low detection limit (sub‐femtomolar), high selectivity and reusability. Considering the straightforward concept, near error‐free identification capacity and hypothetically outstanding scalability, the DNA‐FET described here has potential as a foundation for further exploration of advanced RAM technology in the DNA data storage process.

Non-Destructive Testing Using Eddy Current Sensors for Defect Detection in Additively Manufactured Titanium and Stainless-Steel Parts.

In this study, different eddy-current based probe designs (absolute and commercial reflection) are used to detect artificial defects with different sizes and at different depths in parts composed of stainless-steel (316) and titanium (TI-64) made by Laser Additive Manufacturing (LAM). The measured defect signal value using the probes is in the range of (20–200) millivolts. Both probes can detect subsurface defects on stainless-steel samples with average surface roughness of 11.6 µm and titanium samples with average surface roughness of 8.7 µm. It is found the signal reading can be improved by adding a coating layer made of thin paper to the bottom of the probes. The layer will decrease the surface roughness effect and smooth out the detected defect signal from any ripples. The smallest subsurface artificial defect size detected by both probes is an artificially made notch with 0.07 mm width and 25 mm length. In addition, both probes detected subsurface artificial blind holes in the range of 0.17 mm–0.3 mm radius. Results show that the absolute probe is more suitable to detect cracks and incomplete fusion holes, whereas the reflection probe is more suitable to detect small diameter blind holes. The setup can be used for defect detection during the additive manufacturing process once the melt pool is solidified.

Preparation of Rat Sciatic Nerve for Ex Vivo Neurophysiology.

Ex vivo preparations enable the study of many neurophysiological processes in isolation from the rest of the body while preserving local tissue structure. This work describes the preparation of rat sciatic nerves for ex vivo neurophysiology, including buffer preparation, animal procedures, equipment setup and neurophysiological recording. This work provides an overview of the different types of experiments possible with this method. The outlined method aims to provide 6 h of stimulation and recording on extracted peripheral nerve tissue in tightly controlled conditions for optimal consistency in results. Results obtained using this method are A-fibre compound action potentials (CAP) with peak-to-peak amplitudes in the millivolt range over the entire duration of the experiment. CAP amplitudes and shapes are consistent and reliable, making them useful to test and compare new electrodes to existing models, or the effects of interventions on the tissue, such as the use of chemicals, surgical alterations, or neuromodulatory stimulation techniques. Both conventional commercially available cuff electrodes with platinum-iridium contacts and custom-made conductive elastomer electrodes were tested and gave similar results in terms of nerve stimulus strength-duration response.

Taste Sensor Using Ionic Polymer Metal Composite

The usage of ionic polymer metal composite (IPMC) being an electroactive polymer is prevalent in different engineering applications. IPMC are synthetic composite nanomaterials which show artificial muscle behavior under applied voltage or electric impetus. When an electrical potential is applied across the two membranes, the positively charged conjugated and hydrated cations migrate toward the negative electrode. This migration creates an osmotic pressure gradient across the membrane; hence, the strip gets deformed or bent. On the other hand, IPMC strips are capable of generating electrical potential under the action of stretching or bending (thereby acting as a sensor). In this letter, the authors report the pragmatic application of the IPMC strip to study a taste sensor. The sensing characteristics of IPMC strips are applied to sense five general tastes (sweet, sour, bitter, salty, and spicy). Primarily, IPMCs are immersed into individual solutions and kept for 15 min for doping action. Thus, different solutions having distinct concentration of ions will lead to distinct identifications. In this present investigation, the authors have instigated the IPMC strip as a sensor; when an IPMC strip is bent or deformed, an analogous voltage in the range of millivolts is generated across the membranes. Second, clammy IPMCs are bent in the clockwise and again in the counterclockwise direction (10°) to record the corresponding voltage. A set of experimental data was collected, which divulged unique characteristics for different solutions pertinent to different tastes. Thus, IPMC strips are able to recognize different taste senses.

Design analysis of vibrational input to torque energy system

The development of digital technology in the Industrial Age 4.0 focuses on the application of the Internet of Things (IoT), Virtual Reality (VR) and Augmented Reality (AR). IoT as one of the main topics for technological advancement, which is useful for improving information and communication that is developing in the fields of manufacturing, infrastructure, business, economy etc. The development in the field of material technology can make small materials where the energy requirement to generate a device only requires a millivolt range of power, so by using energy from the surrounding environment which is converted into electrical energy, a device design for energy harvesting is required. The purpose of this research is to design a device that is sourced from various vibrations and converted into electrical energy. The concept of designing a vibration conversion mechanism into electric energy is by combining and optimizing the design of several existing tools (technologies). This research was tested experimentally by utilizing braking force. Tests are carried out using a data logger for further processing. From the results of the braking test, it is able to produce a maximum voltage of 0.9 V with a braking force of 34.72 N.

Design and simulation of stacked PVDF layers with ZnO for piezoelectric nanodevices

Stacked PVDF (polyvinylidene difluoride) polymer with zinc oxide (ZnO) coatings for its improved piezoelectricity properties like electric potential, displacement and von mises stress over single layered piezoelectric devices is designed. A thin PVDF polymer is used as a substrate, stacked with a ZnO coated PVDF sheet is analysed for multiple studies and boundary conditions based on both piezoelectric and converse piezoelectric effects. An electric potential of 7.63 mV is generated with a maximum displacement of 0.71 nm on the application of a force 100 N/m 2 in the negative X direction. The potential generated by the stacked PVDF layer, 13 µm thick, ranges in millivolts which can be further applied in fabrication of nanodevice sensors. To test converse piezoelectric properties, a potential difference of 5 V is applied to the material. A displacement of 5.5 nm with a von mises stress of 5*10 5 N/m 2 is detected. The nanodevice material in this domain produces potential difference in the range of nanovolts which is improved and brought in the range of millivolts by this stacked structure.

Two Electrode ECG And EOG System For Monitoring Applications

Heart and Eye are two vital organs in the human system. By knowing the Electrocardiogram (ECG) and Electro-oculogram (EOG), one will be able to tell the stability of the heart and eye respectively. In this project, we have developed a circuit to pick the ECG and EOG signal using two wet electrodes. Here no reference electrode is used. EOG and ECG signals have been acquired from ten healthy subjects. The ECG signal is obtained from two positions, namely wrist and arm position respectively. The picked-up biomedical signal is recorded and heart rate information is extracted from ECG signal using the biomedical workbench. The result found to be promising and acquired stable EOG and ECG signal from the subjects. The total gain required for the arm position is higher than the wrist position for the ECG signal. The total gain necessary for the EOG signal is higher than the ECG signal since the ECG signal is in the range of millivolts whereas EOG signal in the range of microvolts. This two-electrode system is stable, cost-effective and portable while still maintaining high common-mode rejection ratio (CMRR).

Simulation of Local Dissipation Phenomena in the REBCO Insert of the 25-T CSM Magnet: Understanding and Preventing Destructive Thermal Runaway

We recently developed an electrothermal model to study the occurrence and evolution of dissipative zones in a Rare-Earth BaCuO (REBCO) high-temperature superconductor (HTS) coils, considering the local critical current ( Ic ) inhomogeneity with a centimeter-scale resolution. In this study, we present an application of this model, implemented in Comsol Multiphysics, to the REBCO insert of the 25-T CSM magnet developed in the High Field Laboratory for Superconducting Material of Tohoku University. The destructive thermal runaway event or “quench” observed on that coil will be introduced, followed by the modeling approach that was used to model it. We could simulate the coil behavior with a single 2-cm-long defect and verify that a more sensitive detection system in the millivolt range could be used to safely protect such magnets even from such a local defect. In the case of a more usual inhomogeneity distribution of Ic , the temperature rise is more homogenous and safe protection can be reached even at higher detection levels.

Risk Model to Predict Supraventricular Arrhythmias in Multiple Myeloma Patients Undergoing Autologous Stem Cell Transplant

Multiple Myeloma (MM) are often treated with high-dose melphalan and autologous stem cell transplant (ASCT). Cardiac toxicity, including Supraventricular tachyarrhythmias (SVT), is a fairly common complication which may be related to Melphalan, the transplanted stem cells or effects of para-proteinemia on the conduction system. Here, we sought to determine the incidence of SVT and its predisposing factors in this setting. Methods We reviewed the 100-day post-ASCT clinical course of all MM patients treated from 2007 to 2017 that had undergone ASCT at our institution. Clinical data, EKG and Echocardiography data were extracted. QRS amplitude was measured in the V2 precordial lead as the distance from the R peak to S peak. Both atrial fibrillation and atrial flutter were classified as SVT. Results A total of 222 patients were included in the study population. Amifostine was used before all ASCT to reduced oral mucositis. Patient median age was 60.6 (range: 36-79), 110 patients (49%) were male and the 112 female (51%). Median pre-ASCT QRS amplitude was 1.7 millivolt (mV) (range: 0.3-4.4). Median QRS duration was 90 millisecond (mS, range: 60-208). Only 166 patients received a pre-ASCT ECHO. Median time of pre-ASCT and post-ASCT ECHO were 38 days (range: 1-333 days) and 55 days (range: 4-118), respectively. Seventeen patients (8%) developed SVT during or after ASCT with a median time of 12 days post-ASCT (range: 1-97 days). Median time of the length of hospital stay between patients without SVT and with SVT was different, 15 vs. 19 days (p-value Conclusion Taken together, our results suggest that SVT represents an important cause of morbidity and is associated with longer hospital stay for MM patients undergoing ASCT. The presence of abnormal renal function, LVSD, or hypertension at baseline identifies patients at greater risk of developing SVT following ASCT.

Factors Influencing Incidence of Supraventricular Arrhythmias during and after Autologous Stem Cell Transplant in Multiple Myeloma

Multiple Myeloma (MM) are often treated with high-dose melphalan and autologous stem cell transplant (ASCT), followed by maintenance therapy (McCarthy et al. JCO, 2017). Cardiac toxicity is a potentially serious complication and is a dose limiting toxicity of high-dose melphalan. Furthermore, the overall risk of cardiac event is higher in MM patients compared to age- and gender-matched individuals without MM (Kistler et al. Clin Lymph, Myel & Leuk, 2016). Pre-transplant cardiac screening may help prevent major cardiac complications such as severe heart failure, cardiac tamponade, or life-threatening cardiac arrhythmias. Supraventricular tachy arrhythmias (SVT) are a common complication which may be related to Melphalan, the transplanted stem cells or effects of para-proteinemia on the conduction system. Here, we sought to determine the incidence of SVT and its predisposing factors in this setting.Methods: We reviewed the 100-day post-ASCT clinical course of all MM patients treated from 2007 to 2017 that had undergone ASCT at University Hospitals Cleveland Medical Center. Patients also diagnosed with cardiac Light Chain Amyloidosis (AL) were excluded. Clinical data on the following characteristics were collected: patients' demographics, disease characteristics, pre-ASCT comorbidities and cardiovascular-related medication use, electrocardiography (ECG) and echocardiography (ECHO). ECG and ECHO studies was limited to one year prior to ASCT. Presence of left ventricle hypertrophy (LVH), ejection fraction (EF), impaired relaxation or abnormally low QRS voltage on pre-ASCT were recorded. QRS amplitude was measured in the V2 precordial lead as the distance from the R peak to S peak. Both atrial fibrillation and atrial flutter were classified as SVT. Continuous variables were compared using the unpaired t-test, and categorical variables were compared using the two-tailed Fisher's exact test. A multiple logistic regression model was fit to a model containing all the collected potential risk factors. Odds ratios (ORs) and confidence intervals (CIs) were estimated from the estimated betas in the model. A two-tailed p value < 0.05 was considered to be statistically significant.Results: A total of 222 patients were included in the study population. Amifostine was used before all ASCT to reduced oral mucositis. Patient median age was 60.6 (range: 36-79), 110 patients (49%) were male and the 112 female (51%). Median pre-ASCT QRS amplitude was 1.7 millivolt (mV) (range: 0.3-4.4). Median QRS duration was 90 millisecond (mS, range: 60-208). Only 166 patients received a pre-ASCT ECHO. Median time of pre-ASCT and post-ASCT ECHO were 38 days (range: 1-333 days) and 55 days (range: 4-118), respectively. Seventeen patients (8%) developed SVT during or after ASCT with a median time of 12 days post-ASCT (range: 1-97 days). Median time of the length of hospital stay between patients without SVT and with SVT was different, 15 vs. 19 days (p-value < 0.001). There was no statistically significant between average melphalan dose utilized as the conditioning regimen, infused CD34 dosage, transplant-associated weight loss, time from diagnosis or length of pre-ASCT exposure to proteasome inhibitors between two cohorts (Table-1 and 2). Also, there was no association between pre-ASCT use of anti-lipid lowering agents, beta-blockers, angiotensin-converting enzyme inhibitor or angiotensin receptor inhibitors. Out of all pre-ASCT comorbidities renal insufficiency (9% vs. 41%, p-value: 0.017) and HTN (49% vs. 76%, p-value: 0.045) were predictor, of SVT occurrence in the univariate analysis. Multivariate analysis indicated that renal insufficiency at baseline (OR: 3.6, 95% CI: 2.1-4.8, p-value < 0.001), left ventricular systolic dysfunction (LVSD, OR: 3.0, CI: 1.1-5.1, p-value: 0.003), and hypertension (OR: 2.5, CI: 1.2-4.6, p-value: 0.028), were significantly associated with the development of SVT after ASCT (Fig. 1).Conclusion: Taken together, our results suggest that SVT represents an important cause of morbidity and is associated with longer hospital stay for MM patients undergoing ASCT. The presence of abnormal renal function, LVSD, or hypertension at baseline identifies patients at greater risk of developing SVT following ASCT. Further studies are warranted to establish robust risk models that may predict SVT in MM patients prior to and during ASCT. DisclosuresCaimi:ADC Therapeutics: Research Funding; Celgene: Speakers Bureau; Kite Pharma: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees. Malek:Takeda: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Sanofi: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau.

Design and Analysis of an Electro-Optic Type Pressure Transmitter Using Bellows as Primary Sensor

In process industries, an optical transmitting system has a great impact especially for long distance transmission through inflammable and hazardous areas. A combination of bellows and Mach-Zehnder Interferometer (MZI)-based pressure transmitting system has been proposed in this paper. This novel approach is capable to transmit pressure reading to a remote location using an electro-optic modulation in the MZI. The proposed system is the hybrid type and consists of two sections. First part is the electrical type which is responsible for transmission of measured information in an electrical domain (primary) and a second section is designed for transmission of measured information in an optical domain (secondary). Primary part is the combination of bellows, a Hall probe sensor, and a signal conditioning circuit, and the second part consists of the MZI with three electrodes. The pressure is directly applied to the bellows. The magnet is placed at the top of the Bellows and the variation of the magnet positions is sensed by the Hall probe sensor. The response of the Hall probe sensor, in terms of millivolt range, is not capable to perform the electro-optic modulation in the MZI, so it is further amplified by an instrumentation amplifier and a calibrating circuit. The output from the signal conditioning circuit is fed to the MZI so that the intensity of light which is propagating in the MZI is modulated due to the electro-optic effect. Transmission of the optical signal is very much beneficial for the inflammable industry to prevent the sparking like situation. The operation of the system has been explained with the help of derived theoretical equations. The experiment has been done and the performance of the system along with the experimental results is reported in this paper. The proposed system is linear and provides good repeatability with the applied pressure.

Influence of the blood gas transport system on brain millivolt scale direct current potentials in patients with vascular encephalopathy

Introduction . Millivolt Scale direct current potentials (DCP) registered from human scalp differ from other types of estimated electrical activity by closer association with cerebral energetic processes. Intense energy metabolism in the brain increases the difference between acidic products concentrations on both sides of the blood brain barrier which is reflected by higher DCP. Oxygen consumption of is one of the most important components of cerebral energy metabolism. Delivery of oxygen to neuron depends on the characteristics of blood oxygen transport system and cerebral blood flow. Objective . To test the hypothesis that brain DCP depends of the blood oxygen transport system characteristics and cerebral blood flow. Materials and methods. Erythrocytes number, erythrocyte sedimentation rate, hemoglobin and fibrinogen levels in blood were examined i n 135 patients with vascular encephalopathy (VE) Blood flow velocity in major head arteries was estimated using Doppler ultrasound. Associations between blood characteristics and blood flow velocity and the brain DCP, recorded in frontal, central, occipital areas along the midline and in both temporal areas, were determined. Results. Associations between brain DCP and the blood oxygen transport system characteristics as well as the cerebral blood flow velocity were discovered in patients with VE. Averaged values of DCP in all examined areas were significantly different in groups with high and low hemoglobin levels (Fisher coefficient (F) = 5.5; p = 0.02) and corpuscular hemoglobin levels (F = 7.0; p <0.01). The blood flow velocity in the internal carotid artery correlated with DCP in central areas of the head (r = 0.37; p = 0.003). The values of averaged DCP (over all areas) negatively correlated with blood sedimentation rate (r = -0.31; p= 0.002) and fibrinogen levels (r = -0.37; p <0.001). Conclusions . Evidences of the association between DCP and the brain oxygen transport system were obtained. Higher level of hemoglobin and a higher rate of cerebral blood flow promote more intensive rates of brain oxygen consumption. Discovered correlations between the blood oxygen transport system characteristics, cerebral blood flow and brain DCP confirm the potential benefit of using the millivolt range slow brain electrical activity measurement to characterize cerebral energy metabolism in clinical and experimental setting.

Biasing of Capacitive Micromachined Ultrasonic Transducers.

Capacitive micromachined ultrasonic transducers (CMUTs) represent an effective alternative to piezoelectric transducers for medical ultrasound imaging applications. They are microelectromechanical devices fabricated using silicon micromachining techniques, developed in the last two decades in many laboratories. The interest for this novel transducer technology relies on its full compatibility with standard integrated circuit technology that makes it possible to integrate on the same chip the transducers and the electronics, thus enabling the realization of extremely low-cost and high-performance devices, including both 1-D or 2-D arrays. Being capacitive transducers, CMUTs require a high bias voltage to be properly operated in pulse-echo imaging applications. The typical bias supply residual ripple of high-quality high-voltage (HV) generators is in the millivolt range, which is comparable with the amplitude of the received echo signals, and it is particularly difficult to minimize. The aim of this paper is to analyze the classical CMUT biasing circuits, highlighting the features of each one, and to propose two novel HV generator architectures optimized for CMUT biasing applications. The first circuit proposed is an ultralow-residual ripple (<5 [Formula: see text]) HV generator that uses an extremely stable sinusoidal power oscillator topology. The second circuit employs a commercially available integrated step-up converter characterized by a particularly efficient switching topology. The circuit is used to bias the CMUT by charging a buffer capacitor synchronously with the pulsing sequence, thus reducing the impact of the switching noise on the received echo signals. The small area of the circuit (about 1.5 cm2) makes it possible to generate the bias voltage inside the probe, very close to the CMUT, making the proposed solution attractive for portable applications. Measurements and experiments are shown to demonstrate the effectiveness of the new approaches presented.

Verification of the Power and Ground Grids Under General and Hierarchical Constraints

As part of power distribution network verification, one should check if the voltage fluctuations exceed some critical threshold. The traditional simulation-based solution to this problem is intractable due to the large number of possible circuit behaviors. This approach also requires full knowledge of the details of the underlying circuitry, not allowing one to verify the power distribution network early in the design flow. Contrary to previous work on power distribution network verification, we consider the power and ground (P/G) grids together and describe an early verification approach under the framework of current constraints. Then, we present a solution technique in which tight lower and upper bounds on worst case voltage fluctuations are computed via linear programs. Experimental results indicate that the proposed technique results in errors in the range of a few millivolts. In addition to P/G grid verification techniques, we also provide very efficient solution technique to power (single) grid verification under hierarchical current constraints.

ANALYSIS OF DC-POTENTIAL LEVEL IN ASSESSMENT OF BODY FUNCTIONAL STATE (REVIEW)

A review of modern scientific approaches to assessment of the brain energy metabolism by way of recording DC-potential levels has been presented in the article. A DC-potential level is a slowly varying steady potential of the millivolt range. It is one of the types of superslow physiological processes recorded between the brain and reference areas with use of DC amplifiers. It reflects individual characteristics of general and local energy consumption associated with the general brain and nervous system functional state. It has been underlined that the DC-potential level was a quantitative index of body current functional state that determined its physiological activity, presented activity of the neurophysiological mechanisms of permanent purpose supporting cerebral homeostasis in norm and regulating the functional hemispheric asymmetry. There have been shown views of domestic and foreign scientists on the nature of the DC-potential level and physiological patterns of the DC-potential level distribution. The dependence of the dynamics of the DC-potential level indices on the age influences and the cyclic mode of the body functionality has been described. It has been shown that the study of the DC-potential level helped to reveal mechanisms of interdependence of the brain energy metabolism and other body systems, to determine homeostasis features in changing environment, to assess probabilities of psychosomatic pathology and effectiveness of drug therapy. Particular attention has been paid to the analysis of possibilities of using the DC-potential level for establishment of relationships between the body functional activity and the brain energy metabolism and for practical development of new methods for diagnosis of different states.

A Dual-Channel Calibration System for AC Currents and Small AC Voltages

A new current-comparator-based dual-channel calibration system for AC currents and AC voltages in the millivolt range has been developed. The range of generated currents is 1 mA–5 A, and the range of generated voltages is 1–500 mV. The calibration system in-phase and quadrature expanded measurement uncertainties ( $k=2$ ) are within $25\cdot 10^{\mathrm {\mathbf {-6}}}$ . Although the system has been developed primarily for operation at power frequencies, it is also capable of operating at frequencies up to 1000 Hz with slightly increased uncertainties. The traceability to SI units is established through the calibration of AC voltage by means of AC/DC transfer and DC voltage reference, standard resistor, capacitor, and current comparator ratios.

Explicit solution of channel potential and drain current model in symmetric double-gate polysilicon TFTs

A physical and explicit surface potential model for undoped symmetric double-gate polysilicon thin-film transistors has been derived based on an effective charge density approach of Poisson's equation with both exponential deep and tail state terms included. The proposed surface potential calculation is single-piece and eliminates the regional approach. Model predictions are compared to numerical simulations with close agreement, having absolute error in the millivolt range. Furthermore, expressions of the drain current are given for a wide range of operation regions, which have been justified by thorough comparisons with experimental data.

Similarities and differences in cervical and thoracolumbar multisegmental motor responses and the combined use for testing spinal circuitries

Study designExperimental study.ObjectiveTo determine similarities and differences of C7 and T11–12 multisegmental motor responses (MMR) studies for the upper limbs (UL) and lower limbs (LL).SettingsNeuroscience Lab, TWU (School of Physical Therapy, TX, USA).MethodsC7 and T11–12 percutaneous electrical stimulations were applied while recording muscle action potentials from ULs and LLs.ResultsThe procedure of cervical MMR (CMMR) was easier in application than thoracolumbar MMR (TMMR), requiring less current intensities but cause more “jolts” in the trapezius/shoulder complex, due to close proximity of the stimulation electrodes. CMMR evoked large amplitude motor responses in the millivolts range in (UL) muscles, but smaller amplitude signal in (LL) muscles (in microvolts). TMMR evoked large amplitude motor responses in both UL and LL (in millivolts). The MMR amplitude was generally larger in the UL as compared to the LL, in the distal limb muscles more than in the proximal limb muscles. CMMR and TMMR for the UL were comparable in amplitude, latencies and action potential shapes. Signal latencies were longer for distal limb muscles as compared to proximal limb muscles and were slightly longer for LL as compared to UL muscles. MMR signals were either biphasic or triphasic in shape.ConclusionCMMR and TMMR have similarities and differences in the methods and recording signal that must be considered during its clinical applications. Comparing the signal of the UL muscles with CMMR and TMMR could be a useful test for the integrity of the ascending and descending spinal pathways in patients with spinal cord injuries and diseases.

High Speed and High Resolution Self Biased Differential Amplifier based Latch Comparator

In high speed ADC, comparator influences the overall performance of ADC directly. This paper describes a very high speed and high resolution preamplifier comparator. The comparator use a self biased differential amp to increase the output current sinking and sourcing capability. The threshold and width of the new comparator can be reduced to the millivolt (mV) range, the resolution and the dynamic characteristics are good. Based on UMC 0.18um CMOS process model, simulated results show the comparator can work under a 25dB gain, 55MHz speed and 210.10µW power .