Sensors

Editorial

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5 pages, 109 KiB

Open AccessEditorial

Introduction to the Special Issue on “State-of-the-Art Sensor Technology in Japan”

by Yoshiteru Ishida

Sensors 2010, 10(5), 4756-4760; https://doi.org/10.3390/s100504756 - 10 May 2010

Cited by 2 | Viewed by 8317

Abstract

The combination of sensing technology with information and communication technology (ICT) could serve both as global eyes that monitor the environment for environmental issues, and as local eyes that monitor humans for aging society issues. System technology is also required to form such [...] Read more.

The combination of sensing technology with information and communication technology (ICT) could serve both as global eyes that monitor the environment for environmental issues, and as local eyes that monitor humans for aging society issues. System technology is also required to form such global and local eyes. This special issue, “State-of-the-Art Sensor Technology in Japan”, contains articles and reviews related to the monitoring of humans and the environment, and the integration of sensor systems. [...] Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan)

Research

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14 pages, 1107 KiB

Open AccessArticle

Trial of Multidisciplinary Observation at an Expandable Sub-Marine Cabled Station “Off-Hatsushima Island Observatory” in Sagami Bay, Japan

by Takafumi Kasaya, Kyohiko Mitsuzawa, Tada-nori Goto, Ryoichi Iwase, Keizo Sayanagi, Eiichiro Araki, Kenichi Asakawa, Hitoshi Mikada, Tomoki Watanabe, Ichiro Takahashi and Toshiyasu Nagao

Sensors 2009, 9(11), 9241-9254; https://doi.org/10.3390/s91109241 - 18 Nov 2009

Cited by 25 | Viewed by 14136

Abstract

Sagami Bay is an active tectonic area in Japan. In 1993, a real-time deep sea floor observatory was deployed at 1,175 m depth about 7 km off Hatsushima Island, Sagami Bay to monitor seismic activities and other geophysical phenomena. Video cameras monitored biological [...] Read more.

Sagami Bay is an active tectonic area in Japan. In 1993, a real-time deep sea floor observatory was deployed at 1,175 m depth about 7 km off Hatsushima Island, Sagami Bay to monitor seismic activities and other geophysical phenomena. Video cameras monitored biological activities associated with tectonic activities. The observation system was renovated completely in 2000. An ocean bottom electromagnetic meter (OBEM), an ocean bottom differential pressure gauge (DPG) system, and an ocean bottom gravity meter (OBG) were installed January 2005; operations began in February of that year. An earthquake (M5.4) in April 2006, generated a submarine landslide that reached the Hatsushima Observatory, moving some sensors. The video camera took movies of mudflows; OBEM and other sensors detected distinctive changes occurring with the mudflow. Although the DPG and OBG were recovered in January 2008, the OBEM continues to obtain data. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan)

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21 pages, 370 KiB

Open AccessArticle

An Immunity-Based Anomaly Detection System with Sensor Agents

by Takeshi Okamoto and Yoshiteru Ishida

Sensors 2009, 9(11), 9175-9195; https://doi.org/10.3390/s91109175 - 18 Nov 2009

Cited by 9 | Viewed by 13347

Abstract

This paper proposes an immunity-based anomaly detection system with sensor agents based on the specificity and diversity of the immune system. Each agent is specialized to react to the behavior of a specific user. Multiple diverse agents decide whether the behavior is normal [...] Read more.

This paper proposes an immunity-based anomaly detection system with sensor agents based on the specificity and diversity of the immune system. Each agent is specialized to react to the behavior of a specific user. Multiple diverse agents decide whether the behavior is normal or abnormal. Conventional systems have used only a single sensor to detect anomalies, while the immunity-based system makes use of multiple sensors, which leads to improvements in detection accuracy. In addition, we propose an evaluation framework for the anomaly detection system, which is capable of evaluating the differences in detection accuracy between internal and external anomalies. This paper focuses on anomaly detection in user’s command sequences on UNIX-like systems. In experiments, the immunity-based system outperformed some of the best conventional systems. Full article

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15 pages, 1487 KiB

Open AccessArticle

New Method for Estimation of Aeolian Sand Transport Rate Using Ceramic Sand Flux Sensor (UD-101)

by Keiko Udo

Sensors 2009, 9(11), 9058-9072; https://doi.org/10.3390/s91109058 - 13 Nov 2009

Cited by 26 | Viewed by 12022

Abstract

In this study, a new method for the estimation of aeolian sand transport rate was developed; the method employs a ceramic sand flux sensor (UD-101). UD-101 detects wind-blown sand impacting on its surface. The method was devised by considering the results of wind [...] Read more.

In this study, a new method for the estimation of aeolian sand transport rate was developed; the method employs a ceramic sand flux sensor (UD-101). UD-101 detects wind-blown sand impacting on its surface. The method was devised by considering the results of wind tunnel experiments that were performed using a vertical sediment trap and the UD-101. Field measurements to evaluate the estimation accuracy during the prevalence of unsteady winds were performed on a flat backshore. The results showed that aeolian sand transport rates estimated using the developed method were of the same order as those estimated using the existing method for high transport rates, i.e., for transport rates greater than 0.01 kg m^–1 s^–1. Full article

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16 pages, 407 KiB

Open AccessArticle

Adaptive Sensing Based on Profiles for Sensor Systems

by Yoshiteru Ishida and Masahiro Tokumitsu

Sensors 2009, 9(11), 8422-8437; https://doi.org/10.3390/s91108422 - 26 Oct 2009

Cited by 9 | Viewed by 11092

Abstract

This paper proposes a profile-based sensing framework for adaptive sensor systems based on models that relate possibly heterogeneous sensor data and profiles generated by the models to detect events. With these concepts, three phases for building the sensor systems are extracted from two [...] Read more.

This paper proposes a profile-based sensing framework for adaptive sensor systems based on models that relate possibly heterogeneous sensor data and profiles generated by the models to detect events. With these concepts, three phases for building the sensor systems are extracted from two examples: a combustion control sensor system for an automobile engine, and a sensor system for home security. The three phases are: modeling, profiling, and managing trade-offs. Designing and building a sensor system involves mapping the signals to a model to achieve a given mission. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan)

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14 pages, 609 KiB

Open AccessArticle

Chalcogenide Glass Optical Waveguides for Infrared Biosensing

by Marie-Laure Anne, Julie Keirsse, Virginie Nazabal, Koji Hyodo, Satoru Inoue, Catherine Boussard-Pledel, Hervé Lhermite, Joël Charrier, Kiyoyuki Yanakata, Olivier Loreal, Jenny Le Person, Florent Colas, Chantal Compère and Bruno Bureau

Sensors 2009, 9(9), 7398-7411; https://doi.org/10.3390/s90907398 - 15 Sep 2009

Cited by 137 | Viewed by 16759

Abstract

Due to the remarkable properties of chalcogenide (Chg) glasses, Chg optical waveguides should play a significant role in the development of optical biosensors. This paper describes the fabrication and properties of chalcogenide fibres and planar waveguides. Using optical fibre transparent in the mid-infrared [...] Read more.

Due to the remarkable properties of chalcogenide (Chg) glasses, Chg optical waveguides should play a significant role in the development of optical biosensors. This paper describes the fabrication and properties of chalcogenide fibres and planar waveguides. Using optical fibre transparent in the mid-infrared spectral range we have developed a biosensor that can collect information on whole metabolism alterations, rapidly and in situ. Thanks to this sensor it is possible to collect infrared spectra by remote spectroscopy, by simple contact with the sample. In this way, we tried to determine spectral modifications due, on the one hand, to cerebral metabolism alterations caused by a transient focal ischemia in the rat brain and, in the other hand, starvation in the mouse liver. We also applied a microdialysis method, a well known technique for in vivo brain metabolism studies, as reference. In the field of integrated microsensors, reactive ion etching was used to pattern rib waveguides between 2 and 300 μm wide. This technique was used to fabricate Y optical junctions for optical interconnections on chalcogenide amorphous films, which can potentially increase the sensitivity and stability of an optical micro-sensor. The first tests were also carried out to functionalise the Chg planar waveguides with the aim of using them as (bio)sensors. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan)

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16 pages, 965 KiB

Open AccessArticle

Detecting Specific Health-Related Events Using an Integrated Sensor System for Vital Sign Monitoring

by Mourad Adnane, Zhongwei Jiang, Samjin Choi and Hoyoung Jang

Sensors 2009, 9(9), 6897-6912; https://doi.org/10.3390/s90906897 - 1 Sep 2009

Cited by 20 | Viewed by 12216

Abstract

In this paper, a new method for the detection of apnea/hypopnea periods in physiological data is presented. The method is based on the intelligent combination of an integrated sensor system for long-time cardiorespiratory signal monitoring and dedicated signal-processing packages. Integrated sensors are a [...] Read more.

In this paper, a new method for the detection of apnea/hypopnea periods in physiological data is presented. The method is based on the intelligent combination of an integrated sensor system for long-time cardiorespiratory signal monitoring and dedicated signal-processing packages. Integrated sensors are a PVDF film and conductive fabric sheets. The signal processing package includes dedicated respiratory cycle (RC) and QRS complex detection algorithms and a new method using the respiratory cycle variability (RCV) for detecting apnea/hypopnea periods in physiological data. Results show that our method is suitable for online analysis of long time series data. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan)

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17 pages, 483 KiB

Open AccessArticle

Optical Sensors Based on Whispering Gallery Modes in Fluorescent Microbeads: Size Dependence and Influence of Substrate

by Alexandre Francois and Michael Himmelhaus

Sensors 2009, 9(9), 6836-6852; https://doi.org/10.3390/s90906836 - 31 Aug 2009

Cited by 35 | Viewed by 12525

Abstract

Whispering gallery modes in surface-fixated fluorescent polystyrene microbeads are studied in view of their capability of sensing changes in the refractive index of the beads’ environment by exposing them to water/glycerol mixtures of varying composition. The mode positions are analyzed by simultaneous fitting [...] Read more.

Whispering gallery modes in surface-fixated fluorescent polystyrene microbeads are studied in view of their capability of sensing changes in the refractive index of the beads’ environment by exposing them to water/glycerol mixtures of varying composition. The mode positions are analyzed by simultaneous fitting for mode number, bead radius, and environmental index. Down to a diameter of 8 μm, the sensor response follows the index of the bulk solution very well. For smaller bead sizes, some deviations occur, in particular for fluid indices not too different from that of water, which might be attributed to the presence of the substrate. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan)

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14 pages, 1768 KiB

Open AccessArticle

Monitoring System for Farming Operations with Wearable Devices Utilized Sensor Networks

by Tokihiro Fukatsu and Teruaki Nanseki

Sensors 2009, 9(8), 6171-6184; https://doi.org/10.3390/s90806171 - 4 Aug 2009

Cited by 20 | Viewed by 13033

Abstract

In order to automatically monitor farmers’ activities, we propose a farm operation monitoring system using “Field Servers” and a wearable device equipped with an RFID reader and motion sensors. Our proposed system helps in recognizing farming operations by analyzing the data from the [...] Read more.

In order to automatically monitor farmers’ activities, we propose a farm operation monitoring system using “Field Servers” and a wearable device equipped with an RFID reader and motion sensors. Our proposed system helps in recognizing farming operations by analyzing the data from the sensors and detected RFID tags that are attached to various objects such as farming materials, facilities, and machinery. This method can be applied to various situations without changing the conventional system. Moreover, this system provides useful information in real-time and controls specific machines in a coordinated manner on the basis of recognized operation. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan)

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12 pages, 607 KiB

Open AccessArticle

Distortion of Near-Surface Seawater Temperature Structure by a Moored-Buoy Hull and Its Effect on Skin Temperature and Heat Flux Estimates

by Yoshimi Kawai, Kentaro Ando and Hiroshi Kawamura

Sensors 2009, 9(8), 6119-6130; https://doi.org/10.3390/s90806119 - 31 Jul 2009

Cited by 7 | Viewed by 10398

Abstract

Previous studies have suggested that the accuracy of temperature measurements by surface-moored buoys may be affected by distortions of the near-surface temperature structure by the buoy hull on calm, sunny days. We obtained the first definite observational evidence that the temperature near the [...] Read more.

Previous studies have suggested that the accuracy of temperature measurements by surface-moored buoys may be affected by distortions of the near-surface temperature structure by the buoy hull on calm, sunny days. We obtained the first definite observational evidence that the temperature near the hull was not horizontally homogeneous at the same nominal depth. We observed large temperature differences of 1.0 K or more between thermometers at 0.2 m depth. The distortion of the surface temperature field yielded an error in estimates of daytime net surface heat flux up to more than 30 Wm^–². Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan)

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24 pages, 527 KiB

Open AccessArticle

Extended Averaged Learning Subspace Method for Hyperspectral Data Classification

by Hasi Bagan, Wataru Takeuchi, Yoshiki Yamagata, Xiaohui Wang and Yoshifumi Yasuoka

Sensors 2009, 9(6), 4247-4270; https://doi.org/10.3390/s90604247 - 3 Jun 2009

Cited by 8 | Viewed by 12715

Abstract

Averaged learning subspace methods (ALSM) have the advantage of being easily implemented and appear to outperform in classification problems of hyperspectral images. However, there remain some open and challenging problems, which if addressed, could further improve their performance in terms of classification accuracy. [...] Read more.

Averaged learning subspace methods (ALSM) have the advantage of being easily implemented and appear to outperform in classification problems of hyperspectral images. However, there remain some open and challenging problems, which if addressed, could further improve their performance in terms of classification accuracy. We carried out experiments mainly by using two kinds of improved subspace methods (namely, dynamic and fixed subspace methods), in conjunction with the [0,1] and [-1,+1] normalization methods. We used different performance indicators to support our experimental studies: classification accuracy, computation time, and the stability of the parameter settings. Results are presented for the AVIRIS Indian Pines data set. Experimental analysis showed that the fixed subspace method combined with the [0,1] normalization method yielded higher classification accuracy than other subspace methods. Moreover, ALSMs are easily applied: only two parameters need to be set, and they can be applied directly to hyperspectral data. In addition, they can completely identify training samples in a finite number of iterations. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan)

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17 pages, 500 KiB

Open AccessArticle

Guided Wave and Damage Detection in Composite Laminates Using Different Fiber Optic Sensors

by Fucai Li, Hideaki Murayama, Kazuro Kageyama and Takehiro Shirai

Sensors 2009, 9(5), 4005-4021; https://doi.org/10.3390/s90504005 - 25 May 2009

Cited by 64 | Viewed by 13605

Abstract

Guided wave detection using different fiber optic sensors and their applications in damage detection for composite laminates were systematically investigated and compared in this paper. Two types of fiber optic sensors, namely fiber Bragg gratings (FBG) and Doppler effect-based fiber optic (FOD) sensors, [...] Read more.

Guided wave detection using different fiber optic sensors and their applications in damage detection for composite laminates were systematically investigated and compared in this paper. Two types of fiber optic sensors, namely fiber Bragg gratings (FBG) and Doppler effect-based fiber optic (FOD) sensors, were addressed and guided wave detection systems were constructed for both types. Guided waves generated by a piezoelectric transducer were propagated through a quasi-isotropic carbon fiber reinforced plastic (CFRP) laminate and acquired by these fiber optic sensors. Characteristics of these fiber optic sensors in ultrasonic guided wave detection were systematically compared. Results demonstrated that both the FBG and FOD sensors can be applied in guided wave and damage detection for the CFRP laminates. The signal-to-noise ratio (SNR) of guided wave signal captured by an FOD sensor is relatively high in comparison with that of the FBG sensor because of their different physical principles in ultrasonic detection. Further, the FOD sensor is sensitive to the damage-induced fundamental shear horizontal (SH₀) guided wave that, however, cannot be detected by using the FBG sensor, because the FOD sensor is omnidirectional in ultrasound detection and, in contrast, the FBG sensor is severely direction dependent. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan)

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21 pages, 688 KiB

Open AccessArticle

Use of Human Senses as Sensors

by Yoshiaki Sugawara, Chie Sugimoto, Sachiko Minabe, Yoshie Iura, Mai Okazaki, Natuki Nakagawa, Miwa Seto, Saki Maruyama, Miki Hirano and Ichiro Kitayama

Sensors 2009, 9(5), 3184-3204; https://doi.org/10.3390/s90503184 - 27 Apr 2009

Cited by 6 | Viewed by 13008

Abstract

This paper is an overview of our recent findings obtained by the use of human senses as sensors, suggesting that human senses might be indispensable sensors, not only for practical uses but also for gaining a deeper understanding of humans. From this point [...] Read more.

This paper is an overview of our recent findings obtained by the use of human senses as sensors, suggesting that human senses might be indispensable sensors, not only for practical uses but also for gaining a deeper understanding of humans. From this point of view, two kinds of studies, both based on semantic responses of participants, deserve emphasis. One study assessed the efficacy of the photocatalytic elimination of stains or bio-aerosols from an air environment using TiO₂ as well as the photocatalytic deodorizing efficacy of a TiO₂-type deodorizer; the other study evaluated the changes in perception of a given aroma while inhaling the fragrance of essential oils. In the latter study, we employed a sensory test for evaluating changes in perception of a given aroma. Sensory tests were conducted twice, when participants were undergoing the Kraepelin mental performance test (mental arithmetic) or an auditory task (listening to environmental natural sounds), once before the task (pre-task) and once after the task (post-task). The perception of fragrance was assessed by 13 contrasting pairs of adjectives as a function of the task assigned to participants. The obtained findings illustrate subtle nuances regarding how essential oils manifest their potency and how olfactory discrimination and responses occur in humans. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan)

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22 pages, 375 KiB

Open AccessArticle

A Feature Extraction Method Based on Information Theory for Fault Diagnosis of Reciprocating Machinery

by Huaqing Wang and Peng Chen

Sensors 2009, 9(4), 2415-2436; https://doi.org/10.3390/s90402415 - 1 Apr 2009

Cited by 48 | Viewed by 14335

Abstract

This paper proposes a feature extraction method based on information theory for fault diagnosis of reciprocating machinery. A method to obtain symptom parameter waves is defined in the time domain using the vibration signals, and an information wave is presented based on information [...] Read more.

This paper proposes a feature extraction method based on information theory for fault diagnosis of reciprocating machinery. A method to obtain symptom parameter waves is defined in the time domain using the vibration signals, and an information wave is presented based on information theory, using the symptom parameter waves. A new way to determine the difference spectrum of envelope information waves is also derived, by which the feature spectrum can be extracted clearly and machine faults can be effectively differentiated. This paper also compares the proposed method with the conventional Hilbert-transform-based envelope detection and with a wavelet analysis technique. Practical examples of diagnosis for a rolling element bearing used in a diesel engine are provided to verify the effectiveness of the proposed method. The verification results show that the bearing faults that typically occur in rolling element bearings, such as outer-race, inner-race, and roller defects, can be effectively identified by the proposed method, while these bearing faults are difficult to detect using either of the other techniques it was compared to. Full article

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15 pages, 1172 KiB

Open AccessArticle

Measurement and Evaluation of Finger Tapping Movements Using Log-linearized Gaussian Mixture Networks

by Keisuke Shima, Toshio Tsuji, Akihiko Kandori, Masaru Yokoe and Saburo Sakoda

Sensors 2009, 9(3), 2187-2201; https://doi.org/10.3390/s90302187 - 26 Mar 2009

Cited by 39 | Viewed by 13505

Abstract

This paper proposes a method to quantitatively measure and evaluate finger tapping movements for the assessment of motor function using log-linearized Gaussian mixture networks (LLGMNs). First, finger tapping movements are measured using magnetic sensors, and eleven indices are computed for evaluation. After standardizing [...] Read more.

This paper proposes a method to quantitatively measure and evaluate finger tapping movements for the assessment of motor function using log-linearized Gaussian mixture networks (LLGMNs). First, finger tapping movements are measured using magnetic sensors, and eleven indices are computed for evaluation. After standardizing these indices based on those of normal subjects, they are input to LLGMNs to assess motor function. Then, motor ability is probabilistically discriminated to determine whether it is normal or not using a classifier combined with the output of multiple LLGMNs based on bagging and entropy. This paper reports on evaluation and discrimination experiments performed on finger tapping movements in 33 Parkinson’s disease (PD) patients and 32 normal elderly subjects. The results showed that the patients could be classified correctly in terms of their impairment status with a high degree of accuracy (average rate: 93:1 § 3:69%) using 12 LLGMNs, which was about 5% higher than the results obtained using a single LLGMN. Full article

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13 pages, 977 KiB

Open AccessArticle

Discrepancy Between ASTER- and MODIS- Derived Land Surface Temperatures: Terrain Effects

by Yuanbo Liu, Yousuke Noumi and Yasushi Yamaguchi

Sensors 2009, 9(2), 1054-1066; https://doi.org/10.3390/s90201054 - 17 Feb 2009

Cited by 14 | Viewed by 11260

Abstract

The MODerate resolution Imaging Spectroradiometer (MODIS) and the Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) are onboard the same satellite platform NASA TERRA. Both MODIS and ASTER offer routine retrieval of land surface temperatures (LSTs), and the ASTER- and MODIS-retrieved LST products have [...] Read more.

The MODerate resolution Imaging Spectroradiometer (MODIS) and the Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) are onboard the same satellite platform NASA TERRA. Both MODIS and ASTER offer routine retrieval of land surface temperatures (LSTs), and the ASTER- and MODIS-retrieved LST products have been used worldwide. Because a large fraction of the earth surface consists of mountainous areas, variations in elevation, terrain slope and aspect angles can cause biases in the retrieved LSTs. However, terrain-induced effects are generally neglected in most satellite retrievals, which may generate discrepancy between ASTER and MODIS LSTs. In this paper, we reported the terrain effects on the LST discrepancy with a case examination over a relief area at the Loess Plateau of China. Results showed that the terrain-induced effects were not major, but nevertheless important for the total LST discrepancy. A large local slope did not necessarily lead to a large LST discrepancy. The angle of emitted radiance was more important than the angle of local slope in generating the LST discrepancy. Specifically, the conventional terrain correction may be unsuitable for densely vegetated areas. The distribution of ASTER-to-MODIS emissivity suggested that the terrain correction was included in the generalized split window (GSW) based approach used to rectify MODIS LSTs. Further study should include the classification-induced uncertainty in emissivity for reliable use of satellite-retrieved LSTs over relief areas. Full article

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28 pages, 199 KiB

Open AccessArticle

An Effective Mobile Sensor Control Method for Sparse Sensor Networks

by Kriengsak Treeprapin, Akimitsu Kanzaki, Takahiro Hara and Shojiro Nishio

Sensors 2009, 9(1), 327-354; https://doi.org/10.3390/s90100327 - 8 Jan 2009

Cited by 8 | Viewed by 7962

Abstract

In this paper, we propose an effective mobile sensor control method, named DATFM (Data Acquisition and Transmission with Fixed and Mobile node) for sparse sensor networks. DATFM uses two types of sensor nodes, fixed node and mobile node. The data acquired by [...] Read more.

In this paper, we propose an effective mobile sensor control method, named DATFM (Data Acquisition and Transmission with Fixed and Mobile node) for sparse sensor networks. DATFM uses two types of sensor nodes, fixed node and mobile node. The data acquired by nodes are accumulated on a fixed node before being transferred to the sink node. In addition, DATFM transfers the accumulated data efficiently by constructing a communication route of multiple mobile nodes between fixed nodes. We also conduct simulation experiments to evaluate the performance of DATFM. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan)

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Review

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27 pages, 3556 KiB

Open AccessReview

Recent Advances in Sensing Oropharyngeal Swallowing Function in Japan

by Takahiro Ono, Kazuhiro Hori, Yuji Masuda and Toyohiko Hayashi

Sensors 2010, 10(1), 176-202; https://doi.org/10.3390/s100100176 - 28 Dec 2009

Cited by 40 | Viewed by 18715

Abstract

Dysphagia (difficulty in swallowing) is an important issue in the elderly because it causes aspiration pneumonia, which is the second largest cause of death in this group. It also causes decline in activities of daily living and quality of life. The oral phase [...] Read more.

Dysphagia (difficulty in swallowing) is an important issue in the elderly because it causes aspiration pneumonia, which is the second largest cause of death in this group. It also causes decline in activities of daily living and quality of life. The oral phase of swallowing has been neglected, despite its importance in the evaluation of dysphagia, because adequate protocols and measuring devices are unavailable. However, recent advances in sensor technology have enabled straightforward, non-invasive measurement of the movement of important swallowing-related organs such as the lips and tongue, as well as the larynx. In this article, we report the present state and possibility of clinical application of such systems developed in Japan. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan)

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21 pages, 9350 KiB

Open AccessReview

Implantable CMOS Biomedical Devices

by Jun Ohta, Takashi Tokuda, Kiyotaka Sasagawa and Toshihiko Noda

Sensors 2009, 9(11), 9073-9093; https://doi.org/10.3390/s91109073 - 17 Nov 2009

Cited by 84 | Viewed by 18705

Abstract

The results of recent research on our implantable CMOS biomedical devices are reviewed. Topics include retinal prosthesis devices and deep-brain implantation devices for small animals. Fundamental device structures and characteristics as well as in vivo experiments are presented. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan)

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11 pages, 659 KiB

Open AccessReview

Label-Free Electrical Detection Using Carbon Nanotube-Based Biosensors

by Kenzo Maehashi and Kazuhiko Matsumoto

Sensors 2009, 9(7), 5368-5378; https://doi.org/10.3390/s90705368 - 8 Jul 2009

Cited by 91 | Viewed by 17180

Abstract

Label-free detections of biomolecules have attracted great attention in a lot of life science fields such as genomics, clinical diagnosis and practical pharmacy. In this article, we reviewed amperometric and potentiometric biosensors based on carbon nanotubes (CNTs). In amperometric detections, CNT-modified electrodes were [...] Read more.

Label-free detections of biomolecules have attracted great attention in a lot of life science fields such as genomics, clinical diagnosis and practical pharmacy. In this article, we reviewed amperometric and potentiometric biosensors based on carbon nanotubes (CNTs). In amperometric detections, CNT-modified electrodes were used as working electrodes to significantly enhance electroactive surface area. In contrast, the potentiometric biosensors were based on aptamer-modified CNT field-effect transistors (CNTFETs). Since aptamers are artificial oligonucleotides and thus are smaller than the Debye length, proteins can be detected with high sensitivity. In this review, we discussed on the technology, characteristics and developments for commercialization in label-free CNT-based biosensors. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan)

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