A Wireless Passive Pressure-Sensing Method for Cryogenic Applications Using Magnetoresistors.

In this study, we developed a novel wireless, passive pressure-sensing method functional at cryogenic temperatures (-196 °C). The currently used pressure sensors are inconvenient and complicated in cryogenic environments for their weak low-temperature tolerances and long wires for power supply and data transmission. We propose a novel pressure-sensing method for cryogenic applications by only using low-temperature-tolerant passive devices. By innovatively integrating a magnetoresistor (MR) on a backscattering antenna, the pressure inside a cryogenic environment is transferred to a wirelessly obtainable return loss. Wireless passive measurement is thus achieved using a backscattering method. In the measurement, the pressure causes a relative displacement between the MR and a magnet. The MR's resistance changes with the varied magnetic field, thus modulating the antenna's return loss. The experimental results indicate that our fabricated sensor successfully identified different pressures, with high sensitivities of 4.3 dB/MPa at room temperature (24 °C) and 1.3 dB/MPa at cryogenic temperature (-196 °C). Additionally, our method allows for simultaneous wireless readings of multi sensors via a single reading device by separating the frequency band of each sensor. Our method performs low-cost, simple, robust, passive, and wireless pressure measurement at -196 °C; thus, it is desirable for cryogenic applications.

Wearable EMG Measurement Device Using Polyurethane Foam for Motion Artifact Suppression.

We propose the use of a specially designed polyurethane foam with a plateau region in its mechanical characteristics-where stress remains nearly constant during deformation-between the electromyography (EMG) electrode and clothing to suppress motion artifacts in EMG measurement. Wearable EMG devices are receiving attention for monitoring muscle weakening due to aging. However, daily EMG measurement has been challenging due to motion artifacts caused by changes in the contact pressure between the bioelectrode and the skin. Therefore, this study aims to measure EMG signals in daily movement environments by controlling the contact pressure using polyurethane foam between the bioelectrode on the clothing and the skin. Through mechanical calculations and finite element method simulations of the polyurethane foam's effect, we clarified that the characteristics of the polyurethane foam significantly influence contact pressure control and that the contact pressure is adjustable through the polyurethane foam thickness. The optimization of the design successfully controlled the contact pressure between the bioelectrode and skin from 1.0 kPa to 2.0 kPa, effectively suppressing the motion artifact in EMG measurement.

Analyses of BER-referred noise-to-signal ratio in online measurements of high-baud-rate coherent receivers.

Digital coherent transmission features a very large transmission bandwidth and has played a main role in core optical transmission networks. With the progress of semiconductor technologies, practical coherent transceivers with rates over 100 Gbaud are becoming feasible. With such advances, the transceiver components must have lower power consumption and lower costs, and it becomes important to know how each component contributes to the overall transmission performance. Here, to decompose the effects of noise factors in high-baud-rate DP-16QAM transmissions, we used the theoretical relationship between the bit error rate (BER) and noise-to-signal ratio (NSR) and performed linear analyses. The NSR could be decomposed into individual noise contributions according to dependences on the inverse signal and local photocurrents. The obtained parameters were shown to be useful for predicting required optical signal-to-noise ratio (ROSNR) characteristics.

Comparative Studies on Electrodes for Rumen Bacteria Microbial Fuel Cells.

Microbial fuel cells (MFCs) using rumen bacteria have been proposed as a power source for running devices inside cattle. In this study, we explored the key parameters of the conventional bamboo charcoal electrode in an attempt to improve the amount of electrical power generated by the microbial fuel cell. We evaluated the effects of the electrode's surface area, thickness, and rumen content on power generation and determined that only the electrode's surface area affects power generation levels. Furthermore, our observations and bacterial count on the electrode revealed that rumen bacteria concentrated on the surface of the bamboo charcoal electrode and did not penetrate the interior, explaining why only the electrode's surface area affected power generation levels. A Copper (Cu) plate and Cu paper electrodes were also used to evaluate the effect of different electrodes on measuring the rumen bacteria MFC's power potential, which had a temporarily higher maximum power point (MPP) compared to the bamboo charcoal electrode. However, the open circuit voltage and MPP decreased significantly over time due to the corrosion of the Cu electrodes. The MPP for the Cu plate electrode was 775 mW/m2 and the MPP for the Cu paper electrode was 1240 mW/m2, while the MPP for bamboo charcoal electrodes was only 18.7 mW/m2. In the future, rumen bacteria MFCs are expected to be used as the power supply of rumen sensors.

Margined Horn-Shaped Air Chamber for Body-Conduction Microphone.

The sound amplification ratios of sealed air chambers with different shapes were quantitatively compared to design a body-conduction microphone to measure animal scratching sounds. Recently, quantitative monitoring of scratching intensity in dogs has been required. We have already developed a collar with a body-conduction microphone to measure body-conducted scratching sounds. However, the air chamber, one of the components of the body-conduction microphone, has not been appropriately designed. This study compared the amplification ratios of air chambers with different shapes through numerical analysis and experiments. According to the results, the horn-shaped air chamber achieved the highest amplification performance, at least for sound frequencies below 3 kHz. The simulated amplification ratio of the horn-shaped air chamber with a 1 mm height and a 15 mm diameter was 52.5 dB. The deformation of the bottom of the air chamber affected the amplification ratio. Adjusting the margin of the margined horn shape could maintain its amplification ratio at any pressing force. The simulated and experimental amplification ratios of the margined horn-shaped air chamber were 53.4 dB and 19.4 dB, respectively.

Urethane-Foam-Embedded Silicon Pressure Sensors including Stress-Concentration Packaging Structure for Driver Posture Monitoring.

We propose urethane-foam-embedded silicon pressure sensors, including a stress-concentration packaging structure, for integration into a car seat to monitor the driver's cognitive state, posture, and driving behavior. The technical challenges of embedding silicon pressure sensors in urethane foam are low sensitivity due to stress dispersion of the urethane foam and non-linear sensor response caused by the non-uniform deformation of the foam. Thus, the proposed package structure includes a cover to concentrate the force applied over the urethane foam and frame to eliminate this non-linear stress because the outer edge of the cover receives large non-linear stress concentration caused by the geometric non-linearity of the uneven height of the sensor package and ground substrate. With this package structure, the pressure sensitivity of the sensors ranges from 0 to 10 kPa. The sensors also have high linearity with a root mean squared error of 0.049 N in the linear regression of the relationship between applied pressure and sensor output, and the optimal frame width is more than 2 mm. Finally, a prototype 3 × 3 sensor array included in the proposed package structure detects body movements, which will enable the development of sensor-integrated car seats.

Valve-Actuator-Integrated Reference Electrode for an Ultra-Long-Life Rumen pH Sensor.

We demonstrated a newly developed Ag/AgCl reference electrode- with a valve-actuator for two years or longer rumen pH monitoring. Previous studies on pH sensors reported that the short lifetime of Ag/AgCl reference electrodes is caused by an outflow of internal electrolyte. We introduced a valve-actuator into a liquid junction to reduce the outflow by intermittent measurement. The results indicated that the potential change when switching the liquid junction was less than 0.5 mV and its response time was less than 0.083 s. In the 24-h potential measurement with the valve-actuator-integrated reference electrode (VAIRE), the valve was actuated once every hour, and the standard deviation of the potential was 0.29 mV. The lifetime of the VAIRE was estimated at 2.0 years calculating from an electrolyte outflow, which is significantly longer than that of conventional reference electrodes. A pH sensor using the VAIRE was estimated to operate for 2.0 years with the pH error ≤0.1, which meets the requirement of cows' rumen pH monitoring.

Minimized Bolus-Type Wireless Sensor Node with a Built-In Three-Axis Acceleration Meter for Monitoring a Cow's Rumen Conditions.

Monitoring rumen conditions in cows is important because a dysfunctional rumen system may cause death. Sub-acute ruminal acidosis (SARA) is a typical disease in cows, and is characterized by repeated periods of low ruminal pH. SARA is regarded as a trigger for rumen atony, rumenitis, and abomasal displacement, which may cause death. In previous studies, rumen conditions were evaluated by wireless sensor nodes with pH measurement capability. The primary advantage of the pH sensor is its ability to continuously measure ruminal pH. However, these sensor nodes have short lifetimes since they are limited by the finite volume of the internal liquid of the reference electrode. Mimicking rumen atony, we attempt to evaluate the rumen condition using wireless sensor nodes with three-axis accelerometers. The theoretical life span of such sensor nodes depends mainly on the transmission frequency of acceleration data and the size of the battery, and the proposed sensor nodes are 30.0 mm in diameter and 70.0 mm in length and have a life span of over 600 days. Using the sensor nodes, we compare the rumen motility of the force transducer measurement with the three-axis accelerometer data. As a result, we can detect discriminative movement of rumen atony.

Biomonitoring of mercury, cadmium, and lead exposure in Japanese children: a cross-sectional study.

OBJECTIVES: To measure current Hg, Cd, and Pb exposure in Japanese children, and to estimate dietary intakes of foods responsible for high body burden. METHODS: Blood, hair, and urine samples were collected from 9 to 10-year-old 229 children in Asahikawa and measured for Hg, Cd, and Pb in these matrices. Diet history questionnaire was used to estimate intake of marine foods and other food items. Hg level was measured by cold vapor atomic absorption spectrometry. Cd and Pb levels were determined with inductively coupled plasma mass spectrometry. RESULTS: Geometric mean (GM) of blood Hg, Cd, and Pb was 4.55 µg/L, 0.34 µg/L, and 0.96 µg/dL, respectively. Urinary Cd level was 0.34 µg/g creatinine (GM) and hair Hg was 1.31 µg/g (GM). Approximately one-third (35%) of blood samples had Hg level above the U.S. EPA reference dose (RfD; 5.8 µg/L). Hair Hg level exceeded U.S. EPA RfD (1.2 µg/g) in 59 % samples. Children in the upper quartile of blood Hg level had significantly higher intake of large predatory fish species compared to those in the lower quartile of blood Hg. CONCLUSIONS: Those with high blood Hg level may be explained by more frequent intake of big predatory fish. Cd and Pb exposure is generally low among Japanese children. As no safety margin exists for Pb exposure and high exposure to MeHg is noted in Japanese population; periodic biomonitoring and potential health risk assessment should continue in high-risk populations, notably among children.

Ultra-compact coherent receiver with serial interface for pluggable transceiver.

An ultra-compact integrated coherent receiver with a volume of 1.3 cc using a quad-channel transimpedance amplifier (TIA)-IC chip with a serial peripheral interface (SPI) is demonstrated for the first time. The TIA with the SPI and photodiode (PD) bias circuits, a miniature dual polarization optical hybrid, an octal-PD and small optical coupling system enabled the realization of the compact receiver. Measured transmission performance with 32 Gbaud dual-polarization quadrature phase shift keying signal is equivalent to that of the conventional multi-source agreement-based integrated coherent receiver with dual channel TIA-ICs. By comparing the bit-error rate (BER) performance with that under continuous SPI access, we also confirmed that there is no BER degradation caused by SPI interface access. Such an ultra-compact receiver is promising for realizing a new generation of pluggable transceivers.

Flexible Iron-On Sensor Embedded in Smart Sock for Gait Event Detection.

Portable and wearable electronics for biomechanical data collection have become a growing part of everyday life. As smart technology improves and integrates into our lives, some devices remain ineffective, expensive, or difficult to access. We propose a washable iron-on textile pressure sensor for biometric data acquisition. Biometric data, such as human gait, are a powerful tool for the monitoring and diagnosis of ambulance and physical activity. To demonstrate this, our washable iron-on device is embedded into a sock and compared to gold standard force plate data. Biomechanical testing showed that our embedded sensor displayed a high aptitude for gait event detection, successfully identifying over 96% of heel strike and toe-off gait events. Our device demonstrates excellent attributes for further investigations into low-cost, washable, and highly versatile iron-on textiles for specialized biometric analysis.

[Allergy and immunotoxicology in preventive and clinical medicine from theory to practice: Occupational allergy and isocyanate-induced asthma].

Genetic and environmental factors and their interactions cause diseases and deteriorate health (Genetic and Environmental Interaction). Exposure to environmental factors plays a major role in the deterioration of health in the workplace.Occupational asthma (OA) is a common disorder in the workplace. Approaches to OA are well described and discussed in "Japanese Guideline for Diagnosis and Management of Occupational Allergic Diseases" by the Japanese Society of Occupational and Environmental Allergy. According to the guideline, OA and work-aggravated asthma comprise work-related asthma, and OA can be further divided into two disease entities: sensitizer-induced OA and irritant-induced OA. The guidelines also describe diagnostic and therapeutic strategies for OA. Since a definitive diagnosis of OA requires a comprehensive decision based on a detailed interview on clinical symptoms related to employment status and clinical tests, including inhalation tests of suspected substances as needed, the possibility of OA should be considered as the first step toward diagnosis of the patient. Otherwise, OA may not be diagnosed. Therapeutic strategies include exposure avoidance, environmental arrangements in the workplace, utilization of social resources for workers, and conventional pharmacotherapy for asthma.Artificially synthesized small compounds are used in various industries and can cause allergies. For example, isocyanates are small compounds in the -NCO group, which have been toxicologically studied. It was later shown that isocyanate could cause various nontoxic adverse health effects, including allergic reactions. Since small agents with low molecular weights bind to proteins, detecting their specific immunoglobulin E (IgE) antibodies targeting small compounds is generally difficult. In contrast, isocyanate-specific IgE antibodies are detectable in individuals with isocyanate allergies.Suspecting OA is essential in cases exposed to newly synthesized compounds, or to those that are already known but applied to new uses, which can be better understood and predicted by studying the health effects of isocyanates.Academic interest in various issues related to allergies, immunology, and toxicology in the workplace includes clinical medicine, epidemiology, and epigenetics related to environmental exposure. Further advanced research in these areas is necessary and promising.

NP body domain and PB2 contribute to increased virulence of H5N1 highly pathogenic avian influenza viruses in chickens.

The molecular basis of pathogenicity of H5N1 highly pathogenic avian influenza (HPAI) viruses in chickens remains largely unknown. H5N1 A/chicken/Yamaguchi/7/2004 virus (CkYM7) replicates rapidly in macrophages and vascular endothelial cells in chickens, causing sudden death without fever or gross lesions, while H5N1 A/duck/Yokohama/aq10/2003 virus (DkYK10) induces high fever, severe gross lesions, and a prolonged time to death, despite the 98% amino acid identity between the two viruses. To explore the molecular basis of this difference in pathogenicity, a series of eight single-gene reassortant viruses from these HPAI viruses were compared for pathogenicity in chickens. Two reassortants possessing the NP or PB2 gene from DkYK10 in the CkYM7 background reduced pathogenicity compared to other reassortants or CkYM7. Inversely, reassortants possessing the NP or PB2 gene of CkYM7 in the DkYK10 background (rgDkYK-PB2(Ck), rgDkYK-NP(Ck)) replicated quickly and reached higher titers than DkYK10, accompanied by more rapid and frequent apoptosis of macrophages. The rgDkYK-NP(Ck) and rgDkYK-PB2(Ck) reassortants also replicated more rapidly in chicken embryo fibroblasts (CEFs) than did rgDkYK10, but replication of these viruses was similar to that of CkYM7 and DkYK10 in duck embryo fibroblasts. A comparison of pathogenicities of seven rgDkYK10 mutants with a single amino acid substitution in NP(Dk) demonstrated that valine at position 105 in the NP(Ck) was responsible for the increased pathogenicity in chickens. NP(Ck), NP(105V), and PB2(Ck) enhanced the polymerase activity of DkYK10 in CEFs. These results indicate that both NP and PB2 contribute to the high pathogenicity of the H5N1 HPAI viruses in chickens, and valine at position 105 of NP may be one of the determinants for adaptation of avian influenza viruses from ducks to chickens.

Emergence of avian influenza viruses with enhanced transcription activity by a single amino acid substitution in the nucleoprotein during replication in chicken brains.

To explore the genetic basis of the pathogenesis and adaptation of avian influenza viruses (AIVs) to chickens, the A/duck/Yokohama/aq10/2003 (H5N1) (DkYK10) virus was passaged five times in the brains of chickens. The brain-passaged DkYK10-B5 caused quick death of chickens through rapid and efficient replication in tissues, accompanied by severe apoptosis. Genome sequence comparison of two viruses identified a single amino acid substitution at position 109 in NP from isoleucine to threonine (NP (I)109(T)). By analyzing viruses constructed by the reverse-genetic method, we established that the NP (I)109(T) substitution also contributed to increased viral replication and polymerase activity in chicken embryo fibroblasts, but not in duck embryo fibroblasts. Real-time RT-PCR analysis demonstrated that the NP (I)109(T) substitution enhances mRNA synthesis quickly and then cRNA and viral RNA (vRNA) synthesis slowly. Next, to determine the mechanism underlying the appearance of the NP (I)109(T) substitution during passages, four H5N1 highly pathogenic AIVs (HPAIVs) were passaged in the lungs and brains of chicken embryos. Single-nucleotide polymorphism analysis, together with a database search, suggests that the NP (I)109(T) mutation would be induced frequently during replication of HPAIVs in brains, but not in lungs. These results demonstrate that the amino acid at position 109 in NP enhances viral RNA synthesis and the pathogenicity of highly pathogenic avian influenza viruses in chickens and that the NP mutation emerges quickly during replication of the viruses in chicken brains.

Combination of Micro-Corrugation Process and Pre-Stretched Method for Highly Stretchable Vertical Wavy Structured Metal Interconnects.

Metal interconnects with a vertical wavy structure have been studied to realize high-density and low-electric-resistance stretchable interconnects. This study proposed a new method for fabricating vertical wavy structured metal interconnects that comprises the pre-stretch method and the micro-corrugation process. The pre-stretch method is a conventional method in which a metal film is placed on a pre-stretched substrate, and a vertical wavy structure is formed using the return force of the substrate. The micro-corrugation process is a recent method in which a metal foil is bent vertically and continuously using micro-gears. In the proposed method, the pitch of the vertical wavy structured interconnect fabricated using the micro-corrugation process is significantly narrowed using the restoring force of the pre-stretched substrate, with stretchability improvement of up to 165%, which is significantly higher than that of conventional vertical wavy structured metal interconnects. The electrical resistance of the fabricated interconnect was low (120-160 mΩ) and stable (±2 mΩ or less) until breakage by strain. In addition, the fabricated interconnect exhibits durability of more than 6500 times in a 30% strain cycle test.

Stress concentration-relocating interposer in electronic textile packaging using thermoplastic elastic polyurethane film with via holes for bearing textile stretch.

Electronic textile (e-textile) devices require mechanically reliable packaging that can bear up to 30% stretch induced by textile crimp stretch, because the boundary between the rigid electronic components and the soft fabric circuit in the e-textile is prone to rupture due to mismatch of their mechanical properties. Here, we describe a thin stress-concentration-relocating interposer that can sustain a textile stretch of up to 36%, which is greater than the 16% stretch of conventional packaging. The stress-concentration-relocating interposer consists of thin soft thermoplastic polyurethane film with soft via holes and is inserted between the electronic components and fabric circuit in order to move the area of stress concentration from the wiring area of the fabric circuit to the film. A finite element method (FEM) simulation showed that when the fabric is stretched by 30%, the boundary between the electrical components and the insulation layer is subjected to 90% strain and 2.5 MPa stress, whereas, at 30% strain, the boundary between the devices and the wiring is subjected to only 1.5 MPa stress, indicating that the concentration of stress in the wiring is reduced. Furthermore, it is shown that an optimal interposer structure that can bear a 30% stretch needs insulating polyurethane film in excess of 100 µm thick. Our thin soft interposer structure will enable LEDs and MEMS sensors to withstand stretching in several types of fabric.

Arsenic methylation capacity and its correlation with skin lesions induced by contaminated drinking water consumption in residents of chronic arsenicosis area.

Chronic exposure to excess level of arsenic through contaminated drinking water is associated with many injuries, among which skin lesions are the most prominent. In this study, we measured the concentrations of inorganic arsenic (iAs), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) in the blood of the residents of arsenicosis area, who demonstrated different skin lesion grade from mild, moderate to advanced. We evaluated the individual methylation capacity by two indices of the first and secondary methylation ratio (FMR and SMR). We found that SMR of moderate and advanced groups were markedly lower than that of mild group. Significant negative correlation was found between SMR of all the subjects and the grade of skin lesion, with Spearman's correlation coefficient of -0.429 (P = 0.016). Moreover, blood MMA proportion of moderate and advanced groups was found to be significantly higher than that of the mild group. These results suggest that low secondary arsenic methylation capacity and high MMA proportion are associated with the severity of arsenic-related skin lesions. Our findings evaluated by blood speciation is consistent with that evaluated by the generally accepted urinary arsenic speciation in the relationship between arsenic methylation capacity and arsenic-related lesions.

Phenotypes influencing the transmissibility of highly pathogenic avian influenza viruses in chickens.

To identify critical phenotypes that affect avian influenza virus transmission in chickens, we compared the transmissibility of three H5N1 highly pathogenic viruses of different pathogenicity in chickens by monitoring the exact time of death using wireless thermo-sensors. This study showed that, despite quick deaths, the most virulent H5N1 A/chicken/Yamaguchi/7/2004 transmitted quickly in chickens via contact and airborne routes. Intermediate virulent H5N1 A/chicken/Miyazaki/K11/2007 spread moderately and less virulent H5N1 A/duck/Yokohama/aq10/2003, causing severe clinical signs and a long period to death, spread slowly among the animals. The transmissibility was correlated with virus titres of oropharyngeal and cloacal swabs, and the time for swab virus titres to reach 50 % chicken infective dose affected the transmission speed. These results demonstrate that peak virus titres excreted and the time required for virus titres to reach a minimal chicken infectious dose may be the critical phenotypes influencing the transmissibility of highly pathogenicity avian influenza viruses in chickens.

Association of increased pathogenicity of Asian H5N1 highly pathogenic avian influenza viruses in chickens with highly efficient viral replication accompanied by early destruction of innate immune responses.

The Asian H5N1 highly pathogenic avian influenza (HPAI) viruses have been increasing in pathogenicity in diverse avian species since 1996 and are now widespread in Asian, European, and African countries. To better understand the basis of the increased pathogenicity of recent Asian H5N1 HPAI viruses in chickens, we compared the fevers and mean death times (MDTs) of chickens infected with the Asian H5N1 A/chicken/Yamaguchi/7/04 (CkYM7) strain with those infected with the H5N1 Duck/Yokohama/aq10/03 (DkYK10) strain, using a wireless thermosensor. Asian H5N1 CkYM7 caused peracute death in chickens before fever could be induced, whereas DkYK10 virus induced high fevers and had a long MDT. Real-time PCR analyses of cytokine mRNA expressions showed that CkYM7 quickly induced antiviral and proinflammatory cytokine mRNA expressions at 24 h postinfection (hpi) that suddenly decreased at 32 hpi. In contrast, these cytokine mRNA expressions increased at 24 hpi in the DkYK10 group, but decreased from 48 hpi onward to levels similar to those resulting from infection with the low-pathogenicity H5N2 A/chicken/Ibaraki/1/2004 strain. Sequential titrations of viruses in lungs, spleens, and kidneys demonstrated that CkYM7 replicated rapidly and efficiently in infected chickens and that the viral titers were more than twofold higher than those of DkYK10. CkYM7 preferentially and efficiently replicated in macrophages and vascular endothelial cells, while DkYK10 grew moderately in macrophages. These results indicate that the increased pathogenicity in chickens of the recent Asian H5N1 HPAI viruses may be associated with extremely rapid and high replication of the virus in macrophages and vascular endothelial cells, which resulted in disruption of the thermoregulation system and innate immune responses.

Effect of Au Film Thickness and Surface Roughness on Room-Temperature Wafer Bonding and Wafer-Scale Vacuum Sealing by Au-Au Surface Activated Bonding.

Au-Au surface activated bonding (SAB) using ultrathin Au films is effective for room-temperature pressureless wafer bonding. This paper reports the effect of the film thickness (15-500 nm) and surface roughness (0.3-1.6 nm) on room-temperature pressureless wafer bonding and sealing. The root-mean-square surface roughness and grain size of sputtered Au thin films on Si and glass wafers increased with the film thickness. The bonded area was more than 85% of the total wafer area when the film thickness was 100 nm or less and decreased as the thickness increased. Room-temperature wafer-scale vacuum sealing was achieved when Au thin films with a thickness of 50 nm or less were used. These results suggest that Au-Au SAB using ultrathin Au films is useful in achieving room-temperature wafer-level hermetic and vacuum packaging of microelectromechanical systems and optoelectronic devices.