scholarly journals Wireless Sensors for Brain Activity—A Survey

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2092
Author(s):  
Mahyar TajDini ◽  
Volodymyr Sokolov ◽  
Ievgeniia Kuzminykh ◽  
Stavros Shiaeles ◽  
Bogdan Ghita
Keyword(s):  
Brain Activity ◽  
Complex Structure ◽  
High Sensitivity ◽  
Lower Sensitivity ◽  
Application Time ◽  
Wearable Eeg ◽  
User Data ◽  
Large Measurement ◽  
Spectrum Band ◽  
Measurement Devices

Over the last decade, the area of electroencephalography (EEG) witnessed a progressive move from high-end large measurement devices, relying on accurate construction and providing high sensitivity, to miniature hardware, more specifically wireless wearable EEG devices. While accurate, traditional EEG systems need a complex structure and long periods of application time, unwittingly causing discomfort and distress on the users. Given their size and price, aside from their lower sensitivity and narrower spectrum band(s), wearable EEG devices may be used regularly by individuals for continuous collection of user data from non-medical environments. This allows their usage for diverse, nontraditional, non-medical applications, including cognition, BCI, education, and gaming. Given the reduced need for standardization or accuracy, the area remains a rather incipient one, mostly driven by the emergence of new devices that represent the critical link of the innovation chain. In this context, the aim of this study is to provide a holistic assessment of the consumer-grade EEG devices for cognition, BCI, education, and gaming, based on the existing products, the success of their underlying technologies, as benchmarked by the undertaken studies, and their integration with current applications across the four areas. Beyond establishing a reference point, this review also provides the critical and necessary systematic guidance for non-medical EEG research and development efforts at the start of their investigation.

scholarly journals 60–700 K CTAT and PTAT Temperature Sensors with 4H-SiC Schottky Diodes

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 942
Author(s):  
Razvan Pascu ◽  
Gheorghe Pristavu ◽  
Gheorghe Brezeanu ◽  
Florin Draghici ◽  
Philippe Godignon ◽  
...  
Keyword(s):  
Low Cost ◽  
Schottky Diodes ◽  
Schottky Contact ◽  
High Sensitivity ◽  
Xrd Analysis ◽  
Absolute Temperature ◽  
Lower Sensitivity ◽  
Readout Circuit ◽  
Sensing Element ◽  
High Performing

A SiC Schottky dual-diode temperature-sensing element, suitable for both complementary variation of VF with absolute temperature (CTAT) and differential proportional to absolute temperature (PTAT) sensors, is demonstrated over 60–700 K, currently the widest range reported. The structure’s layout places the two identical diodes in close, symmetrical proximity. A stable and high-barrier Schottky contact based on Ni, annealed at 750 °C, is used. XRD analysis evinced the even distribution of Ni2Si over the entire Schottky contact area. Forward measurements in the 60–700 K range indicate nearly identical characteristics for the dual-diodes, with only minor inhomogeneity. Our parallel diode (p-diode) model is used to parameterize experimental curves and evaluate sensing performances over this far-reaching domain. High sensitivity, upwards of 2.32 mV/K, is obtained, with satisfactory linearity (R2 reaching 99.80%) for the CTAT sensor, even down to 60 K. The PTAT differential version boasts increased linearity, up to 99.95%. The lower sensitivity is, in this case, compensated by using a high-performing, low-cost readout circuit, leading to a peak 14.91 mV/K, without influencing linearity.

TOWARDS SENSING SINGLE OR A FEW BIO-MOLECULAR ARCHITECTURES: DESIGN OF FUNCTIONAL SURFACES

2008 ◽  
Vol 18 (01) ◽  
pp. 187-194
Author(s):  
PEIJI ZHAO ◽  
DWIGHT WOOLARD ◽  
JORGE M. SEMINARIO ◽  
ROBERT TREW
Keyword(s):  
Density Functional ◽  
High Sensitivity ◽  
Lower Sensitivity ◽  
Label Free ◽  
Dna Molecules ◽  
Surface Attachment ◽  
Biomolecular Sensing ◽  
Aromatic Molecules ◽  
Electrical Sensing ◽  
Silicon Based

There is considerable interest in electrical sensing of biomolecular binding since it has the potential to be label free, to work easily in aqueous environments native to the biomolecules, and to be integrated with small, fast, and inexpensive microelectronoics as detection instrumentation. Although electrochemical methods have been used successfully in detections of DNA molecules with Ag labels at very high sensitivity (~ p ml), detection of DNA molecules in terms of label free techniques has a lower sensitivity (~ μ ml). Here, the surface attachment chemistry is critical towards the detection of ultra-low concentration of biomolecules. In this article, based on density functional theory, we have calculated and analyzed the electrical characteristics of the contact between aromatic molecules and silicon (100) − 2×1 surfaces. Design principles for silicon based electrodes of electrochemically biomolecular sensing instruments for label-free sensing of single or a few biomolecular molecules have also been discussed.

scholarly journals Novel dry electrode EEG headbands for home use: Comparing performance and comfort

2020 ◽  
Vol 6 (3) ◽  
pp. 139-142
Author(s):  
Jens Haueisen ◽  
Patrique Fiedler ◽  
Anna Bernhardt ◽  
Ricardo Gonçalves ◽  
Carlos Fonseca
Keyword(s):  
Brain Activity ◽  
Skin Impedance ◽  
Signal Quality ◽  
The Novel ◽  
Application Time ◽  
Dry Electrodes ◽  
Power Spectral ◽  
Dry Electrode ◽  
Increasing Trend ◽  
Eeg Recordings

AbstractMonitoring brain activity at home using electroencephalography (EEG) is an increasing trend for both medical and non-medical applications. Gel-based electrodes are not suitable due to the gel application requiring extensive preparation and cleaning support for the patient or user. Dry electrodes can be applied without prior preparation by the patient or user. We investigate and compare two dry electrode headbands for EEG acquisition: a novel hybrid dual-textile headband comprising multipin and multiwave electrodes and a neoprene-based headband comprising hydrogel and spidershaped electrodes. We compare the headbands and electrodes in terms of electrode-skin impedance, comfort, electrode offset potential and EEG signal quality. We did not observe considerable differences in the power spectral density of EEG recordings. However, the hydrogel electrodes showed considerably increased impedances and offset potentials, limiting their compatibility with many EEG amplifiers. The hydrogel and spider-shaped electrodes required increased adduction, resulting in a lower wearing comfort throughout the application time compared to the novel headband comprising multipin and multiwave electrodes.

scholarly journals Yebes 40 m radio telescope and the broad band Nanocosmos receivers at 7 mm and 3 mm for line surveys

2021 ◽  
Vol 645 ◽  
pp. A37
Author(s):  
F. Tercero ◽  
J. A. López-Pérez ◽  
J. D. Gallego ◽  
F. Beltrán ◽  
O. García ◽  
...  
Keyword(s):  
Radio Telescope ◽  
Signal To Noise Ratio ◽  
Broad Band ◽  
High Sensitivity ◽  
Lower Sensitivity ◽  
Molecular Chemistry ◽  
Long Baseline ◽  
New Instrumentation ◽  
Frequency Coverage ◽  
Technical Specifications

Context. Yebes 40 m radio telescope is the main and largest observing instrument at Yebes Observatory and is devoted to very long baseline interferometry (VLBI) and single-dish observations since 2010. It has been covering frequency bands between 2 GHz and 90 GHz in discontinuous and narrow windows in most cases in order to match the current needs of the European VLBI Network (EVN) and the Global Millimeter VLBI Array (GMVA). Aims. The Nanocosmos project, a European Union-funded synergy grant, has enabled an increase in the instantaneous frequency coverage of the Yebes 40 m radio telescope, making it possible to observe many molecular transitions with single tunings in single-dish mode. This reduces the observing time and maximises the output from the telescope. Methods. We present technical specifications of the recently installed 31.5−50 GHz (Q band) and 72−90.5 GHz (W band) receivers along with the main characteristics of the telescope at these frequency ranges. We observed IRC+10216, CRL 2688, and CRL 618, which harbour a rich molecular chemistry, to demonstrate the capabilities of the new instrumentation for spectral observations in single-dish mode. Results. Our results show the high sensitivity of the telescope in the Q band. The spectrum of IRC+10126 offers an unprecedented signal-to-noise ratio for this source in this band. On the other hand, the spectrum normalised by the continuum flux towards CRL 618 in the W band demonstrates that the 40 m radio telescope produces comparable results to those from the IRAM 30 m radio telescope, although with a lower sensitivity. The new receivers fulfil one of the main goals of Nanocosmos and open up the possibility to study the spectrum of different astrophysical media with unprecedented sensitivity.

scholarly journals Monitoring "mini-intensity" anticoagulation with warfarin: comparison of the prothrombin time using a sensitive thromboplastin with prothrombin fragment F1+2 levels

Blood ◽  
1992 ◽  
Vol 79 (8) ◽  
pp. 2034-2038 ◽  
Author(s):  
MM Millenson ◽  
KA Bauer ◽  
JP Kistler ◽  
S Barzegar ◽  
L Tulin ◽  
...  
Keyword(s):  
Prothrombin Time ◽  
Factor Xa ◽  
High Sensitivity ◽  
International Normalized Ratio ◽  
Target Range ◽  
Lower Sensitivity ◽  
Sensitivity Index ◽  
Plasma Samples ◽  
Prothrombin Activation

Treatment with warfarin using a target International Normalized Ratio (INR) range of 1.7 to 2.5 is efficacious for many clinical indications, but the minimal intensity of anticoagulation required for antithrombotic protection has yet to be determined. To evaluate whether patients could be reliably monitored with a less intense regimen, we anticoagulated patients with warfarin for several months using a target INR range of 1.3 to 1.6 as determined by prothrombin time (PT) using a sensitive thromboplastin (Dade IS, International Sensitivity Index [ISI] = 1.3). Plasma measurements of F1+2, a marker of factor Xa action on prothrombin in vivo, were also obtained to determine the suppressive effect of warfarin on hemostatic system activity. Overall, 20 of 21 patients with a history of cerebrovascular events (mean age, 61 years) could be reliably regulated with warfarin in the target INR range. F1+2 levels were significantly suppressed from baseline in all patients, with a mean reduction of 49% (range, 28% to 78%). We found a significant relationship between the extent of suppression of prothrombin activation levels and the baseline measurements. A mean reduction of 65% was observed for those patients with baseline F1+2 greater than or equal to 1.5 nmol/L, but only 38% for baseline F1+2 less than or equal to 0.5 nmol/L. Overall, 68% of plasma samples obtained during stable anticoagulation were within the target INR range. PTs were also determined on all plasma samples with two thromboplastins of lower sensitivity (C+, ISI = 2.09; and automated simplastin, ISI = 2.10). Only 47% and 35% of PT determinations, respectively, were within the target range with these reagents. We conclude that prothrombin activation can be significantly suppressed in vivo with use of warfarin in an INR range of 1.3 to 1.6. This level of anticoagulation can be reliably achieved by monitoring PTs with a thromboplastin of high sensitivity.

A high-sensitivity dual-sample synchronous detection photonic crystal fiber sensor

2021 ◽  
pp. 2150306
Author(s):  
Pibin Bing ◽  
Guifang Wu ◽  
Zhongyang Li ◽  
Sheng Yuan ◽  
Hongtao Zhang ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystal Fiber ◽  
Complex Structure ◽  
High Sensitivity ◽  
Structure Design ◽  
Synchronous Detection ◽  
Crystal Fiber ◽  
The Core ◽  
Wavelength Sensitivity ◽  
Air Hole

The photonic crystal fiber (PCF) sensor based on surface plasmon resonance (SPR) technology has flexibility in birefringence, negative dispersion, effective area and nonlinearity and has become a widely studied new fiber. However, there are many problems in the practical application of the sensor, such as complex structure design, not easy to prepare, the low sensitivity of sensing detection, narrow range of refractive index detection of analytes, which greatly limits the application range and functions of PCF sensors. To solve the above problems, this paper adopts a structure with a longer vertical distance between the D-shaped large air hole channel and the core. The energy of the core conduction mode is better limited by the cladding to transmit in the core, and the plasma mode is enhanced, which can effectively increase the wavelength sensitivity. In this paper, the hexagonal double-clad air hole structure and the D-type structure are combined to ensure a simple structure and facilitate manufacturing and production, while the wavelength sensitivity is also greatly improved. The wavelength sensitivity of the dual sample channel can reach up to 16200 nm/RIU and 15800 nm/RIU, which has broad application prospects in the field of high-sensitivity detection.

Abstract 15928: Relative Sparing of Apical Longitudinal Strain for Detection of Cardiac Amyloidosis: Intervendor Variation

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Julia M Simkowski ◽  
Michael Jiang ◽  
NADIA El HANGOUCHE ◽  
Jeesoo Lee ◽  
Milica Marion ◽  
...  
Keyword(s):  
Cardiac Amyloidosis ◽  
Longitudinal Strain ◽  
Global Longitudinal Strain ◽  
High Sensitivity ◽  
High Specificity ◽  
Left Ventricular ◽  
Control Group ◽  
Lower Sensitivity ◽  
Medical Systems ◽  
Roc Curve Analysis

Introduction: Relative apical longitudinal strain (RALS) is defined as (average apical LS/(average basal & mid-ventricular LS)). A threshold of 2 has been found to have high sensitivity and specificity for differentiating cardiac amyloidosis (CA) from other causes of left ventricular hypertrophy (LVH). This threshold was developed using General Electric (GE) software, and its reproducibility among different software vendors is unknown. Hypothesis: In patients with CA, regional segmental LS patterns and relative apical longitudinal strain will vary among software vendors. Methods: Speckle-tracking echocardiography was retroactively performed by an experienced technician on two patient cohorts, CA (n=52) and LVH (n=52), using software from two independent vendors: EchoPAC (GE Medical Systems) and TomTEC (TOMTEC Imaging Systems GMBH). For each vendor and patient, strain values for the basal, mid, and apical segments were averaged to obtain three regional LS values which were then used to calculate global longitudinal strain (GLS) and RALS. Results: EchoPAC demonstrated greater average apical LS (-16.5±5.7 vs -13.1±6.6, p<0.001) and RALS (2.1±0.9 vs 1.7±0.7, p<0.001) compared to TomTEC. Bland-Altman analysis yielded a mean bias of -0.4 with limit of agreement 2.2 (p<0.001) in RALS between the two vendors. ROC curve analysis using a RALS cutoff of 2 to differentiate CA from the overall control group showed similarly high specificity (EchoPAC 85%, TomTEC 83%) between vendors but lower sensitivity for TomTEC (23% vs 45%) (Figure 1). LVH subgroup analysis showed similar comparisons. Overall difference in area-under-curve (AUC) was significant (AUC = 0.78 EchoPAC vs AUC = 0.52 TomTEC, p < 0.001). Conclusions: Software measurements of regional LS and thus RALS vary between vendors. Further efforts are needed for intervendor regional strain fidelity. For now, different RALS thresholds to diagnose CA may be needed for various vendors.

scholarly journals Recording brain activities in unshielded Earth’s field with optically pumped atomic magnetometers

2020 ◽  
Vol 6 (24) ◽  
pp. eaba8792 ◽  
Author(s):  
Rui Zhang ◽  
Wei Xiao ◽  
Yudong Ding ◽  
Yulong Feng ◽  
Xiang Peng ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Medical Diagnosis ◽  
Alpha Rhythm ◽  
Brain Activity ◽  
High Sensitivity ◽  
Noninvasive Method ◽  
Optically Pumped ◽  
Field Noise ◽  
The Relationship ◽  
The Brain

Understanding the relationship between brain activity and specific mental function is important for medical diagnosis of brain symptoms, such as epilepsy. Magnetoencephalography (MEG), which uses an array of high-sensitivity magnetometers to record magnetic field signals generated from neural currents occurring naturally in the brain, is a noninvasive method for locating the brain activities. The MEG is normally performed in a magnetically shielded room. Here, we introduce an unshielded MEG system based on optically pumped atomic magnetometers. We build an atomic magnetic gradiometer, together with feedback methods, to reduce the environment magnetic field noise. We successfully observe the alpha rhythm signals related to closed eyes and clear auditory evoked field signals in unshielded Earth’s field. Combined with improvements in the miniaturization of the atomic magnetometer, our method is promising to realize a practical wearable and movable unshielded MEG system and bring new insights into medical diagnosis of brain symptoms.

scholarly journals Monitoring "mini-intensity" anticoagulation with warfarin: comparison of the prothrombin time using a sensitive thromboplastin with prothrombin fragment F1+2 levels

Blood ◽  
1992 ◽  
Vol 79 (8) ◽  
pp. 2034-2038 ◽  
Author(s):  
MM Millenson ◽  
KA Bauer ◽  
JP Kistler ◽  
S Barzegar ◽  
L Tulin ◽  
...  
Keyword(s):  
Prothrombin Time ◽  
Factor Xa ◽  
High Sensitivity ◽  
International Normalized Ratio ◽  
Target Range ◽  
Lower Sensitivity ◽  
Sensitivity Index ◽  
Plasma Samples ◽  
Prothrombin Activation

Abstract Treatment with warfarin using a target International Normalized Ratio (INR) range of 1.7 to 2.5 is efficacious for many clinical indications, but the minimal intensity of anticoagulation required for antithrombotic protection has yet to be determined. To evaluate whether patients could be reliably monitored with a less intense regimen, we anticoagulated patients with warfarin for several months using a target INR range of 1.3 to 1.6 as determined by prothrombin time (PT) using a sensitive thromboplastin (Dade IS, International Sensitivity Index [ISI] = 1.3). Plasma measurements of F1+2, a marker of factor Xa action on prothrombin in vivo, were also obtained to determine the suppressive effect of warfarin on hemostatic system activity. Overall, 20 of 21 patients with a history of cerebrovascular events (mean age, 61 years) could be reliably regulated with warfarin in the target INR range. F1+2 levels were significantly suppressed from baseline in all patients, with a mean reduction of 49% (range, 28% to 78%). We found a significant relationship between the extent of suppression of prothrombin activation levels and the baseline measurements. A mean reduction of 65% was observed for those patients with baseline F1+2 greater than or equal to 1.5 nmol/L, but only 38% for baseline F1+2 less than or equal to 0.5 nmol/L. Overall, 68% of plasma samples obtained during stable anticoagulation were within the target INR range. PTs were also determined on all plasma samples with two thromboplastins of lower sensitivity (C+, ISI = 2.09; and automated simplastin, ISI = 2.10). Only 47% and 35% of PT determinations, respectively, were within the target range with these reagents. We conclude that prothrombin activation can be significantly suppressed in vivo with use of warfarin in an INR range of 1.3 to 1.6. This level of anticoagulation can be reliably achieved by monitoring PTs with a thromboplastin of high sensitivity.

scholarly journals Ultra-Sensitive Flexible Tactile Sensor Based on Graphene Film

Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 730 ◽  
Author(s):  
Xiaozhou Lü ◽  
Liang Qi ◽  
Hanlun Hu ◽  
Xiaoping Li ◽  
Guanghui Bai ◽  
...  
Keyword(s):  
Industrial Robot ◽  
Graphene Film ◽  
High Sensitivity ◽  
Tactile Sensor ◽  
Measurement Range ◽  
Tactile Sensors ◽  
Piezoresistive Effect ◽  
Large Measurement ◽  
Pet Film ◽  
Maximum Measurement

Flexible tactile sensor can be integrated into artificial skin and applied in industrial robot and biomedical engineering. However, the presented tactile sensors still have challenge in increasing sensitivity to expand the sensor’s application. Aiming at this problem, this paper presents an ultra-sensitive flexible tactile sensor. The sensor is based on piezoresistive effect of graphene film and is composed of upper substrate (PDMS bump with a size of 5 mm × 7 mm and a thickness of 1 mm), medial Graphene/PET film (Graphene/PET film with a size of 5 mm × 7 mm, PET with a hardness of 2H) and lower substrate (PI with fabricated electrodes). We presented the structure and reduced the principle of the sensor. We also fabricated several sample devices of the sensor and carried out experiment to test the performance. The results show that the sensor performed an ultra high sensitivity of 10.80/kPa at the range of 0–4 kPa and have a large measurement range up to 600 kPa. The sensor has 4 orders of magnitude between minimum resolution and maximum measurement range which have great advantage compared with state of the art. The sensor is expected to have great application prospect in robot and biomedical.

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