Nano-cutting mechanism of ion implantation-modified SiC: reducing subsurface damage expansion and abrasive wear

This study utilized ion implantation to modify the material properties of silicon carbide (SiC) to mitigate subsurface damage during SiC machining. The paper analyzed the mechanism of hydrogen ion implantation on the machining performance of SiC at the atomic scale. A molecular dynamics model of nanoscale cutting of an ion-implanted SiC workpiece using a non-rigid regular tetrakaidecahedral diamond abrasive grain was established. The study investigated the effects of ion implantation on crystal structure phase transformation, dislocation nucleation, and defect structure evolution. Results showed ion implantation modification decreased the extension depth of amorphous structures in the subsurface layer, thereby enhancing the surface and subsurface integrity of the SiC workpiece. Additionally, dislocation extension length and volume within the lattice structure were lower in the ion-implanted workpiece compared to non-implanted ones. Phase transformation, compressive pressure, and cutting stress of the lattice in the shear region per unit volume were lower in the ion-implanted workpiece than the non-implanted one. Taking the diamond abrasive grain as the research subject, the mechanism of grain wear under ion implantation was explored. Grain expansion, compression, and atomic volumetric strain wear rate were higher in the non-implanted workpiece versus implanted ones. Under shear extrusion of the SiC workpiece, dangling bonds of atoms in the diamond grain were unstable, resulting in graphitization of the diamond structure at elevated temperatures. This study established a solid theoretical and practical foundation for realizing non-destructive machining at the atomic scale, encompassing both theoretical principles and practical applications. .

Highly Stretchable, Knittable, Wearable Fiberform Hydrovoltaic Generators Driven by Water Transpiration for Portable Self-Power Supply and Self-Powered Strain Sensor

The development of excellently stretchable, highly mobile, and sustainable power supplies is of great importance for self-power wearable electronics. Transpiration-driven hydrovoltaic power generator (HPG) has been demonstrated to be a promising energy harvesting strategy with the advantages of negative heat and zero-carbon emissions. Herein, this work demonstrates a fiber-based stretchable HPG with the advantages of high output, portability, knittability, and sustainable power generation. Based on the functionalized micro-nano water diffusion channels constructed by the discarded mask straps (MSs) and oxidation-treated carbon nanomaterials, the applied water can continuously produce electricity during the spontaneous flow and diffusion. Experimentally, when a tiny 0.1 mL of water encounters one end of the proposed HPG, the centimeter-length device can yield a peak voltage of 0.43 V, peak current of 29.5 µA, and energy density of 5.833 mW h cm-3. By efficiently integrating multiple power generation units, sufficient output power can be provided to drive commercial electronic devices even in the stretched state. Furthermore, due to the reversibility of the electrical output during dynamic stretching-releasing, it can passively convert physiological activities and motion behaviors into quantifiable and processable current signals, opening up HPG's application in the field of self-powered wearable sensing.

Effects of Digitization of Self-Monitoring of Blood Glucose Records Using a Mobile App and the Cloud System on Outpatient Management of Diabetes: Single-Armed Prospective Study

BACKGROUND

In recent years, technologies promoting the digitization of self-monitoring of blood glucose (SMBG) records including app-cloud cooperation systems have emerged. Studies combining these technological interventions with support from remote health care professionals have reported improvements in glycemic control.

OBJECTIVE

To assess the use of an app-cloud cooperation system linked with SMBG devices in clinical settings, we evaluated its effects on outpatient management of diabetes without remote health care professional support.

METHODS

In this multicenter, open-label, and single-armed prospective study, 48 patients with diabetes (including type 1 and type 2) at 3 hospitals in Japan treated with insulin or glucagon-like peptide 1 receptor agonists and performing SMBG used the app-cloud cooperation system for 24 weeks. The SMBG data were automatically uploaded to the cloud via the app. The patients could check their data, and their attending physicians reviewed the data through the cloud prior to the patients' regular visits. The primary outcome was changes in glycated hemoglobin (HbA1c) levels.

RESULTS

Although HbA1c levels did not significantly change in all patients, the frequency of daily SMBG following applying the system was significantly increased before induction at 12 (0.60 per day, 95% CI 0.19-1.00; P=.002) and 24 weeks (0.43 per day, 95% CI 0.02-0.84; P=.04). In the subset of 21 patients whose antidiabetic medication had not been adjusted during the intervention period, a decrease in HbA1c level was observed at 12 weeks (P=.02); however, this significant change disappeared at 24 weeks (P=.49). The Diabetes Treatment Satisfaction Questionnaire total score and "Q4: convenience" and "Q5: flexibility" scores significantly improved after using the system (all P<.05), and 72% (33/46) patients and 76% (35/46) physicians reported that the app-cloud cooperation system helped them adjust insulin doses.

CONCLUSIONS

The digitization of SMBG records and sharing of the data by patients and attending physicians during face-to-face visits improved self-management in patients with diabetes.

TRIAL REGISTRATION

Japan Registry of Clinical Trials (jRCT) jRCTs042190057; https://jrct.niph.go.jp/en-latest-detail/jRCTs042190057.

Highly sensitive piezoresistive and thermally responsive fibrous networks from the in situ growth of PEDOT on MWCNT-decorated electrospun PU fibers for pressure and temperature sensing

Flexible electronics have demonstrated various strategies to enhance the sensory ability for tactile perception and wearable physiological monitoring. Fibrous microstructures have attracted much interest because of their excellent mechanical properties and fabricability. Herein, a structurally robust fibrous mat was first fabricated by electrospinning, followed by a sequential process of functionalization utilizing ultrasonication treatment and in situ polymerization growth. Electrospun polyurethane (PU) microfibers were anchored with multi-walled carbon nanotubes (MWCNTs) to form conductive paths along each fiber by a scalable ultrasonic cavitation treatment in an MWCNT suspension. After, a layer of poly(3,4-ethylene dioxythiophene) (PEDOT) was grown on the surface of PU fibers decorated with MWCNTs to enhance the conductive conjunctions of MWCNTs. Due to the superior electromechanical behaviors and mechanical reinforcement of PEDOT, the PEDOT/MWCNT@PU mat-based device exhibits a wide working range (0-70 kPa), high sensitivity (1.6 kPa-1), and good mechanical robustness (over 18,000 cycles). The PEDOT/MWCNT@PU mat-based sensor also demonstrates a good linear response to different temperature variations because of the thermoelectricity of the PEDOT/MWCNT composite. This novel strategy for the fabrication of multifunctional fibrous mats provides a promising opportunity for future applications for high-performance wearable devices.

Ag Nanoparticle-Thiolated Chitosan Composite Coating Reinforced by Ag-S Covalent Bonds with Excellent Electromagnetic Interference Shielding and Joule Heating Performances

Conductive composite coatings are an important element in flexible electronics research and are widely used in energy transformation, artificial intelligence, and electronic skins. However, the comparatively low electrical conductivity limits their performance in many specific applications, such as electromagnetic interference (EMI) shielding and Joule heating devices. Therefore, the preparation of ultrahigh-electrical conductivity composite coatings with good flexibility and durability remains a great challenge. Herein, we fabricated multifunctional conductive composite coatings based on thiolated chitosan (TCS) and Ag nanoparticles (AgNPs) by an eco-friendly drop-coating method. The three-dimensional conductive network constructed by thermal sintering imparted the coating with an ultrahigh electrical conductivity of up to 67079.4 S/m. Moreover, the coating reinforced by Ag-S covalent bonding exhibits good stability, including heat resistance, chemical resistance, and mechanical stability. In addition, based on the ultrahigh electrical conductivity, the coating exhibits superior EMI shielding effectiveness and Joule heating capability. With 30 wt % of AgNPs in the coating, the EMI shielding effectiveness of the coating reaches 70.2 dB, far exceeding commercial standards. Additionally, the coating can quickly reach a saturation temperature (T_s) of 195.9 °C at a safe drive voltage of 3 V. These excellent performances demonstrate that the robust and flexible highly conductive composite coatings prepared by this method have attractive potential for EMI shielding and thermal management applications as well as in wearable electronics.

Exploring the nonlinear piezoresistive effect of 4H-SiC and developing MEMS pressure sensors for extreme environments

Microelectromechanical system (MEMS) pressure sensors based on silicon are widely used and offer the benefits of miniaturization and high precision. However, they cannot easily withstand high temperatures exceeding 150 °C because of intrinsic material limits. Herein, we proposed and executed a systematic and full-process study of SiC-based MEMS pressure sensors that operate stably from -50 to 300 °C. First, to explore the nonlinear piezoresistive effect, the temperature coefficient of resistance (TCR) values of 4H-SiC piezoresistors were obtained from -50 to 500 °C. A conductivity variation model based on scattering theory was established to reveal the nonlinear variation mechanism. Then, a piezoresistive pressure sensor based on 4H-SiC was designed and fabricated. The sensor shows good output sensitivity (3.38 mV/V/MPa), accuracy (0.56% FS) and low temperature coefficient of sensitivity (TCS) (-0.067% FS/°C) in the range of -50 to 300 °C. In addition, the survivability of the sensor chip in extreme environments was demonstrated by its anti-corrosion capability in H₂SO₄ and NaOH solutions and its radiation tolerance under 5 W X-rays. Accordingly, the sensor developed in this work has high potential to measure pressure in high-temperature and extreme environments such as are faced in geothermal energy extraction, deep well drilling, aeroengines and gas turbines.

Frequency Modulation Approach for High Power Density 100 Hz Piezoelectric Vibration Energy Harvester

Piezoelectric vibration energy harvester (PVEH) is a promising device for sustainable power supply of wireless sensor nodes (WSNs). PVEH is resonant and generates power under constant frequency vibration excitation of mechanical equipment. However, it cannot output high power through off-resonance if it has frequency offset in manufacturing, assembly and use. To address this issue, this paper designs and optimizes a PVEH to harvest power specifically from grid transformer vibration at 100 Hz with high power density of 5.28 μWmm^-3g^-2. Some resonant frequency modulation methods of PVEH are discussed by theoretical analysis and experiment, such as load impedance, additional mass, glue filling, axial and transverse magnetic force frequency modulation. Finally, efficient energy harvesting of 6.1 V output in 0.0226 g acceleration is tested in grid transformer reactor field application. This research has practical value for the design and optimization process of tunable PVEH for a specific vibration source.

Comparison of L-Shaped and U-Shaped Beams in Bidirectional Piezoelectric Vibration Energy Harvesting

The traditional single degree of freedom linear piezoelectric vibration energy harvester (PVEH), such as the cantilever type, mainly works and resonates in a single direction and at a single frequency. To adapt broadband and bidirectional ambient vibration, this paper designs and compares two PVEHs of L-shaped beam and U-shaped beam through COMSOL simulation and prototype test. FEA modeling is introduced for accurate structure design with modal analysis, voltage frequency response analysis, and proof mass analysis with multiphysics electromechanical coupling simulation. Two PVEH prototypes with different gravity angles and clamping angles are tested at 0.1 g acceleration to find the optimal angle for maximum output power. The best clamping angle of L-PVEH is 135° with RMS power of 0.3 mW at 7.9 Hz, and that of U-PVEH is 45° with RMS power of 0.4 mW at 5.0 Hz. The proposed U-PVEH shows more advantages in low broadband and bidirectional vibration energy harvesting.

An ultrasensitive and stretchable strain sensor based on a microcrack structure for motion monitoring

Flexible strain sensors are promising candidates for intelligent wearable devices. Among previous studies, although crack-based sensors have attracted a lot of attention due to their ultrahigh sensitivity, large strain usually causes fractures in the conductive paths. Because of the unstable crack structure, the tradeoff between sensitivity and workable strain range is still a challenge. As carbon nanotubes (CNTs) and silver nanowires (AgNWs) can form a strong interface with the thermoplastic substrate and strengthen the conductive network by capillary force during water evaporation, CNTs and AgNWs were deposited on electrospun TPU fiber mats via vacuum-assisted filtration in this work. The prestretching treatment constructed a microcrack structure that endowed the sensor with the combined characteristics of a wide working range (0~171% strain), ultrahigh sensitivity (a gauge factor of 691 within 0~102% strain, ~2 × 10⁴ within 102~135% strain, and >11 × 10⁴ within 135~171% strain), a fast response time (~65 ms), small hysteresis, and superior durability (>2000 cycles). Subsequently, the sensing mechanism of the sensor was studied. Distributed microcrack propagation based on the "island-bridge" structure was explained in detail, and its influence on the strain-sensing behavior of the sensor was analyzed. Finally, the sensor was assembled to monitor various vibration signals and human motions, demonstrating its potential applications in the fields of electronic skin and human health monitoring.

Association of common carotid artery measurements with the incidence of hypertension: a retrospective cohort study

Background

Diameter, intima–media thickness (IMT), and flow parameters, including resistance index (RI) and pulsatility index (PI), in the common carotid artery (CCA) are markers of arterial remodeling, atherosclerosis, and vascular resistance, respectively. These CCA parameters have usually been evaluated as markers of target organ damage. Little is known about whether these parameters predict a new onset of hypertension.

Purpose

In this study, we investigated the association of CCA parameters including IMT, diameter, RI, and PI with the incidence of hypertension.

Methods

This is an observational study involving 1249 participants (656 women, mean age 69.6 years) without hypertension, who underwent carotid artery ultrasonography at baseline. The participants were divided into elderly group (defined as age ≥70 years) and a middle-aged group. We defined obesity as BMI ≥25 kg/m2. CCA diameter was defined as the distance between the adventitia–media interface on the near wall and the media–adventitia interface on the far wall. IMT was defined as the distance between the lumen–intima and media–adventitia interfaces. RI was calculated as [peak systolic velocity (PSV)- end-diastolic velocity (EDV)]/PSV. PI was calculated as (PSV-EDV)/Vmean. Larger CCA diameter, increased IMT, high RI, and high PI were determined based on the optimal cutoff values from ROC curve analysis.

Results

Over a mean 5.1-year follow-up period, 524 participants developed hypertension. Multivariate logistic regression analyses showed that larger CCA diameter and increased IMT were significant predicators for incident hypertension in elderly group, but not in middle-aged group. High RI, and high PI were significant predicators for incident hypertension in both the two groups. CCA diameter, IMT, and RI predicted the incidence of hypertension only in nonobesity group, whereas PI predicted it in both obesity and nonobesity groups (Table).

Conclusion

CCA parameters assessed by ultrasonography are useful markers to estimate the risk of hypertension. In particular, PI is a better predictor for the incidence of hypertension.

Funding Acknowledgement

Type of funding sources: None.

Association of adipose tissue insulin resistance and serum free fatty acid levels with the incidence of type 2 diabetes: a retrospective cohort study

Background

Insulin resistance in adipose tissue attenuates the suppression of lipolysis, leading to increased free fatty acid (FFA) release. The excess FFA may be involved in the development of type 2 diabetes.

Purpose

In this study, we investigated the association of adipose tissue insulin resistance and serum free fatty acid levels with the incidence of type 2 diabetes.

Methods

This is an observational study involving 6800 participants (3451 women, mean age 69.2 years) without diabetes who underwent 75-g oral glucose tolerance test (OGTT) at baseline. The participants were divided into the obesity and nonobesity groups on the basis of body mass index of ≥25 and &lt;25 kg/m2, respectively. Serum FFA levels were assessed before and 30, 60, and 120 min after glucose ingestion, and the total area under the FFA curve (AUCFFA) was calculated. Adipose tissue insulin resistance was assessed using adipose insulin resistance index (adipo-IR) calculated based on fasting FFA and insulin concentrations. The homeostasis model assessment of insulin resistance (HOMA-IR), and the Matsuda index were evaluated as measures of insulin resistance in the liver and whole-body, respectively. High adipo-IR, high fasting FFA, great AUCFFA high HOMA-IR, and low Matsuda index were determined based on the optimal cutoff values from ROC curve analysis.

Results

Over a mean 5.3-year follow-up period, 485 participants developed type 2 diabetes. Multivariate logistic regression analyses showed that high adipo-IR was a significant predicator for incident type 2 diabetes in the obesity group, but not in nonobesity group. AUCFFA, HOMA-IR, and Matsuda index were significantly associated with incident type 2 diabetes in both the two groups (Table).

Conclusion

Serum FFA levels after glucose loading predict the incidence of type 2 diabetes. Adipose tissue insulin resistance was associated with the risk of type 2 diabetes in individuals with obesity, but not in individuals without obesity.

Funding Acknowledgement

Type of funding sources: None.

Real-time tracking of organ-shape and vessel-locations for surgical navigation using MEMS tri-axis magnetic sensors

Laparoscopic surgery is less invasive to patients; however, fatal bleeding occurs when a surgeon misinterprets the anatomical location of the blood vessels. Therefore, we have proposed a location tracking system by generating an artificial magnetic field around a patient and attaching MEMS magnetic sensor nodes to certain locations of the patient's organs for real-time tracking of the organ shape and vessel locations. This paper presents the detailed system design and configuration. The results suggest that a high spatial resolution of 1-2 mm may be achieved by static and ultralow-frequency magnetic fields for rotation recognition of each sensor node and noise cancelation of the entire system. The algorithm for creating the navigation 'map' has been investigated from both efficiency and accuracy perspectives, which is essential for practical applications of the above system in surgical navigation.

Serum cytokine profiling in neonates with hypoxic ischemic encephalopathy

BACKGROUND

The fetal brain is vulnerable to severe and sustained hypoxia during and after birth, which can lead to hypoxic-ischemic encephalopathy (HIE). HIE is characterized by clinical and laboratory evidence of acute or subacute brain injury. The role of cytokines in the pathogenesis of brain injury and their relation to neurological outcomes of asphyxiated neonates are not fully understood. In this study, we investigated cytokine profile related to cerebral palsy (CP) with neonatal hypoxic ischemic encephalopathy (HIE) and HIE severity.

METHODS

Eligible subjects were HIE newborns with a gestational age between 36 and 42 weeks. We included newborns who was born at our NICU and did not admit to NICU as healthy controls. The study comprised 52 newborns, including 13 with mild to severe HIE and 39 healthy control. Serum cytokine profiles were performed using a LUMINEX cytokine kit (R&D Systems).

RESULTS

VEGF, MCP-1, IL-15, IL-12p70, IL-12p40, IL-1Ra, IL-2, IL-6, IL-7, IL-8, IL-10, IFN-γ, G-CSF and eotaxin in the HIE patients were significantly increased compared with the healthy neonates. In the subgroup analysis, IL-6 and G-CSF were significantly increased in CP infants (n = 5) compared with non-CP infants (n = 8). Five and eight HIE patients were classified into the mild HIE and moderate-severe HIE groups, respectively. IL-6, 10, 1Ra, and G-CSF in the moderate-severe HIE group were significantly higher than those in the mild HIE group.

CONCLUSION

We demonstrated that higher serum IL-6 and G-CSF at birth in HIE patients were associated with CP and moderate-severe HIE.

Broadband vibration energy harvesting for wireless sensor node power supply in train container

Wireless sensor nodes (WSNs) for temperature and humidity monitoring are commonly used in a cold chain logistics container. Energy harvesting technology is expected to realize the sustainable self-power supply for the WSN. Low amplitude and broadband vibration energy harvesting performance are the key points in train application. In this study, two piezoelectric vibration energy harvesters (PVEHs) are designed and simulated via COMSOL. Their low resonant frequencies and high electromechanical sensitivities are realized by big L-shaped mass blocks with different material densities. Their broadband vibration energy harvesting performance is achieved by the stopper and series connection. Experimental data are shown at an acceleration of 0.5 m/s²; PVEH-1 and PVEH-2 have maximum powers of 0.24 mW and 0.1 mW when excited at the resonant frequencies of 13.1 Hz and 18.8 Hz, respectively, and they both have the optimal load resistance of 40 kΩ. Two circuit design styles of two PVEHs, independent and series styles, are proposed for broadband vibration energy harvesting. Experimental results show that the series style has a wider operating frequency bandwidth and shorter charging time. Two PVEHs in series style can be effectively used for power supply of the temperature and humidity WSN in the broadband frequency range of 8.7-22.0 Hz above charging root mean square voltage of 5 V at the acceleration of 3.0 m/s². This scheme is promised to be applied to the cold chain logistics train container.

P4403Sleep quality is associated with visit-to-visit blood pressure variability in elderly people

Background

The proportion of people suffering from poor sleep quality increases with age. Several studies reported that poor sleep quality is involved in elevation of blood pressure (BP) level and the development of hypertension. However, it is unclear whether sleep quality is associated with visit-to-visit BP variability, which is related to the incident cardiovascular disease independent of mean BP.

Purpose

In this study, we investigated the association between sleep quality and visit-to-visit BP variability in elderly people.

Methods

This is an observational study involving 3313 participants without atrial fibrillation, aged 68 years or older, who underwent assessment of sleep quality at general health examination between October 2014 and September 2015, and had more than four visits during the first 3 years following the assessment. Of these, 1951 participants (59%) had hypertension, 488 (17%) had diabetes, 432 (13%) had dyslipidemia, and 333 (10%) were on treatment for, or with a history of, cardiac disease. Sleep quality was evaluated using the Pittsburgh Sleep Quality Index (PSQI), which yields seven component scores (0, 1, 2, or 3 is given for each component). A sum of the seven scores was used to calculate the global PSQI score which ranged from 0 to 21. Higher scores indicated poorer sleep quality. Visit-to-visit BP variability for each individual was evaluated by coefficient of variation (CV, defined as standard deviation/mean).

Results

The mean global PSQI score was 5.2±3.2. The mean CV of SBP and CV of DBP was 6.9±3.0, and 8.0±3.5, respectively. The global PSQI score was significantly associated with CV of SBP (ρ= 0.039, P=0.025), and CV of DBP (ρ= 0.039, P=0.024) in Spearman's rank correlation coefficient test. Multiple regression analyses showed that the global PSQI score was a significant contributor to CV of SBP, and CV of DBP, after adjusting for variables with P values <0.1 in Spearman's test (Table).

Table 1. Multiple regression analysis for blood pressure variability (n=3313) Variables CV of SBP CV of DBP β P β P Age 0.131 <0.001 0.140 <0.001 Female −0.017 0.338 0.023 0.186 Hypertension 0.037 0.032 0.031 0.073 Cardiac disease 0.045 0.009 0.038 0.030 Global PSQI score 0.035 0.042 0.047 0.007

Conclusion

Sleep quality is associated with visit-to-visit BP variability in elderly people.

P6366High blood pressure cut-off by 130/80 mmHg in middle-ages may be valid for predicting heart failure in ages of seventies

Background

ESC/ESH Guidelines (2018) recommended that treated BP values should be targeted to 130/80 mmHg or lower in most patients. However, it remains unclear whether this target in middle-aged population is associated with future development of heart failure.

Purpose

We conducted a retrospective analysis to determine whether high blood pressure cut-off by 130/80 mmHg in the middle-age predicts the risk of heart failure, detected by high N-terminal pro-brain natriuretic peptide (NT-proBNP) level, in the elderly in a cohort in which longitudinal blood pressure records exist.

Methods

The cohort consists of health check examinee who consulted the examination institute between 2015 and 2018 (n=8513), aged 70 years or older, and had previous institution-visit record at least once from 50 to 69 years old. We measured serum NT-proBNP level in the all examinee and defined the group of high NT-proBNP as ≥144 pg/ml [defined as the highest quartile, n=2135 (25%)]. The number of participants whose previous blood pressure records exists was 8123 (95%) for 65–69 years old, 6980 (82%) for 60–64 years old, 5233 (61%) for 55–59 years old, and 3018 (35%) for 50–54 years old, respectively. The each generation subgroups were divided into the three gradual categories according to the blood pressure records: SBP ≥140 and/or DBP ≥90, SBP130–139 and/or DBP80–89, and SBP <130 and DBP <80 mmHg.

Results

Categorization to high NT-proBNP group in ages of 70 or more was significantly associated with the categorization to high blood pressure, which was not only the SBP ≥140 and/or DBP ≥90 mmHg but also the SBP130–139 and/or DBP80–89 mmHg at any time points of previous blood pressure measurements. The multivariable adjusted odds ratios for having high NT-proBNP level in the elderly against the two high blood pressure categories based on the previous blood pressure measurements were shown in the Table.

Table 1. Multivariable adjusted OR for high NT-proBNP level in elderly Age N SBP 130–139 and/or DBP 80–89 SBP ≥140 and/or DBP ≥90 OR P OR P 65–69 8123 1.30 <0.001 1.68 <0.001 60–64 6980 1.26 0.002 1.55 <0.001 55–59 5233 1.25 0.013 1.41 <0.001 50–54 3018 1.32 0.023 1.58 <0.001 Model included age, gender, BMI, serum creatinine, hemoglobin, and presence of antihypertensive medications, and cardiac disease.

Conclusion

High blood pressure cut-off by 130/80 mmHg in the middle-age may be valid to predict the risk of heart failure in the elderly.

Development of Implantable Wireless Sensor Nodes for Animal Husbandry and MedTech Innovation

In this paper, we report the development, evaluation, and application of ultra-small low-power wireless sensor nodes for advancing animal husbandry, as well as for innovation of medical technologies. A radio frequency identification (RFID) chip with hybrid interface and neglectable power consumption was introduced to enable switching of ON/OFF and measurement mode after implantation. A wireless power transmission system with a maximum efficiency of 70% and an access distance of up to 5 cm was developed to allow the sensor node to survive for a duration of several weeks from a few minutes’ remote charge. The results of field tests using laboratory mice and a cow indicated the high accuracy of the collected biological data and bio-compatibility of the package. As a result of extensive application of the above technologies, a fully solid wireless pH sensor and a surgical navigation system using artificial magnetic field and a 3D MEMS magnetic sensor are introduced in this paper, and the preliminary experimental results are presented and discussed.

A novel MEMS compatible lab-on-a-tube technology

We present a novel lab-on-a-tube technology, which is a combination of three-dimensional (3D) cylindrical photolithography and nanoimprint processes, for fabricating microfunctional structures on a tiny tube substrate directly. As an example, electrochemical electrodes, which consisted of Pt work and Ag/AgCl reference electrodes, were successfully fabricated on a 330-μm-diameter polyimide capillary. Using thermal nanoimprint technology, a microdome array with a diameter of 2 μm to about 600 nm was prepared in the work and reference electrodes. The nanoimprinted domes greatly enhanced the electrochemical activity and there were much higher oxidation and reduction current peaks observed in cyclic voltammetry curves of the nanoimprinted electrode than those of the blank electrode without the nanoimprint modification. The nanoimprinted patterns exhibited complicated effects, e.g. the 600-nm-diameter dome sample has higher electrochemical activity than the 2-μm-diameter dome, while the latter has a larger surface. By using the new lab-on-a-tube technology, new bio- and nanomaterials could be integrated directly into electronic devices on tiny tube substrates so that many interesting applications could be expected in medical and life technologies.

Surface patterning of glass via electrostatic imprinting using a platinum mold

Electrostatic imprinting is a highly suitable process for patterning large area and high efficiency glasses because it enables glass patterning at low temperatures with low pressures. Because high DC voltage bias is applied to the mold and glass during the thermal imprinting, the mold materials should have electrical conductivity, appropriate glass adhesion properties, and excellent thermal and electrochemical stability. In this study, thin Pt/Ni molds were fabricated via Si micromachining and electroforming techniques and were then used in the electrostatic imprint process in order to evaluate their feasibility as molds. Under the investigated process conditions, the pattern transfer to glass was accomplished without noticeable degradation of the mold. Furthermore, the process parameter effects on replication fidelity and potential defects were investigated.

Lipid infiltration in the parotid glands: a clinical manifestation of metabolic syndrome

BACKGROUND

The clinical features of lipid infiltration in the parotid glands (LIPG) have not been studied. Monitoring of atomic-bomb survivors for late effects of radiation exposure has provided the opportunity to review the clinical findings of LIPG.

METHODS

A total of 992 atomic-bomb survivors in Nagasaki, Japan underwent lachrymal and salivary secretion tests and anthropometric, biochemical, and abdominal ultrasonographic examinations between 2002 and 2004. Among 465 subjects who had reduced tear and/or salivary excretion, 176 subjects took a salivary magnetic resonance imaging (MRI) examination.

RESULTS

LIPG was detected in 53 of the 176 subjects who had salivary MRI. LIPG cases showed a preponderance of females and fatty liver compared with the subjects without LIPG. Age-and-sex-adjusted regression analysis revealed that body mass index (BMI), low-density lipoprotein cholesterol, triglycerides, hemoglobin A1c, and C-reactive protein were higher, whereas high-density lipoprotein cholesterol and adiponectin were lower, in the subjects with LIPG. Multivariate logistic regression analysis showed that BMI and fatty liver were mutually associated with LIPG independently from radiation dose.

CONCLUSIONS

LIPG associated with BMI, fatty liver, and coronary risk factors was a clinical manifestation of metabolic syndrome.

Effect of Pb Excess Content on Microstructure and Electrical Properties of Sol Gel Derived PZT Thin Films

Lead zirconate titanate (PZT) thin films were fabricated by a three-step heat-treatment process which involves the addition of -10, 0 and 10 mol% excess Pb to the starting solution and spin coating onto Pt/Ti/SiO2/Si substrates. Crystalline phases as well as preferred orientations in PZT films were investigated by X-ray diffraction analysis (XRD). The microstructure and composition of the films were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron probe microanalysis (EPMA), respectively. The well-crystallized perovskite phase and the (100) preferred orientation were obtained by adding 10% excess Pb to the starting solution. It was found that PZT films to which 10% excess Pb was added had better electric properties. The remanent polarization and the coercive field of this film were 34.8 μC/cm2 and 41.7 kV/cm, while the dielectric constant and loss values measured at 1 kHz were approximately 1600 and 0.04, respectively. Dielectric and ferroelectric properties were correlated to the microstructure of the films.

Evaluation of the soft x-ray reflectivity of micropore optics using anisotropic wet etching of silicon wafers

The x-ray reflectivity of an ultralightweight and low-cost x-ray optic using anisotropic wet etching of Si (110) wafers is evaluated at two energies, C K(alpha)0.28 keV and Al K(alpha)1.49 keV. The obtained reflectivities at both energies are not represented by a simple planar mirror model considering surface roughness. Hence, an geometrical occultation effect due to step structures upon the etched mirror surface is taken into account. Then, the reflectivities are represented by the theoretical model. The estimated surface roughness at C K(alpha) (approximately 6 nm rms) is significantly larger than approximately 1 nm at Al K(alpha). This can be explained by different coherent lengths at two energies.

Prevalence of Sjogren syndrome among Nagasaki atomic bomb survivors

OBJECTIVES

Through a comprehensive epidemiological study, we determined Sjögren syndrome (SS) prevalence and examined the association between SS and ionising radiation dose.

METHODS

A total of 1008 atomic bomb survivors in Nagasaki agreed to undergo the tests comprising a questionnaire for xerophthalmia and xerostomia, Schirmer-I test, Saxon test, and tests of anti-SS-A/Ro and anti-SS-B/La antibodies, and, if necessary, Rose Bengal stain test, salivary ultrasonographic and MRI examination from November 2002 through October 2004. Diagnosis of SS was based on the American-European Consensus Group criteria, or a modified version thereof.

RESULTS

Among the 1008 participants (male 398, female 610, average age 71.6 years), 154 participants (15.3%) complained of xerophthalmia, and 264 (26.2%) of xerostomia. Reduced tear flow as assessed by the Schirmer-I test was detected in 371 of 992 participants (37.4%) and reduced saliva flow as assessed by the Saxon test in 203 of 993 participants (20.4%). Among all participants, 38 (3.8%) and 10 (1.0%) participants tested positive for anti-SS-A/Ro and anti-SS-B/La antibodies, respectively. Taking into consideration all the results, 23 participants were diagnosed with SS (primary 20, secondary 3), yielding a prevalence of 2.3%. Although the association between SS and radiation dose was not significant, radiation dose was significantly associated with hyposalivation.

CONCLUSIONS

The present comprehensive epidemiological study reveals that the prevalence of SS was 2.3% among Nagasaki atomic bomb survivors and was not associated with radiation dose. The association between radiation dose and hyposalivation supported the possibility that radiation exposure damaged salivary gland function.

Effects of rapid thermal annealing on nucleation, growth, and properties of lead zirconate titanate films

The nucleation and growth behavior of solgel-derived lead zirconate titanate (PZT) films was investigated at different rapid thermal annealing (RTA) processes. The effects of RTA on PZT film surface morphology, crystal orientation, residual stress, and properties were also studied and are discussed. PZT nucleation and growth behavior were found to be more sensitive to heating rate than to hold time during RTA. Higher heating rates were preferred for uniform PZT nucleation and grain growth, which resulted in dense microstructures, smooth surfaces, and better film ferroelectric properties. Lower heating rates led to strong PZT (100) orientation, better film piezoelectric properties, and low residual stress, but at the risk of film cracks caused by arbitrarily distributed large crystallites with diameters of approximately 300 nm among crystallites with diameters of approximately 30 nm. Furthermore, the residual stress of the PZT film was found to be effectively reduced by extending the hold time.

Microstructures formed on a low fluorescent glass using glassy carbon molding

We report a pattern generation method on galss using hot embossing technology. Microstructures were formed on Borofloat, a low fluorescent glass, using a glassy carbon mold. A cubic block in the size of 100 um x 100 um x 50 um is the basic testing pattern. This block was repeated on a mirror polished glassy carbon wafer with a space in the pitch of 30 um. The whole pattern area is in 15 mm x 15 mm square on this carbon mold. Both the glass wafer and the mold were heated to 655 &#176;C and embossing was processed at 2 MPa under vacuum (0.07 Pa). The state was held for 20 min, and then the embossed piece was cooling down to 200 &#176;C naturally in the vacuum chamber. The pattern on mold were transferred compensate to the glass. Each fabrication cycle is about 1.5 hours. This method shows great potential to fabricate bio-MEMS devices efficiently with a very low cost. The main target is to fabricate the devices for highly sensitive fluorescent detection applications, which is very difficult to be realized using plastic substrates, A multi-channel pattern (with 70 um line and 400 um space) has been generated on a 20 mm square glassy carbon using a laser machine. The pattern replicated on glass chips has been demonstrated.

Micropore x-ray optics using anisotropic wet etching of (110) silicon wafers

To develop x-ray mirrors for micropore optics, smooth silicon (111) sidewalls obtained after anisotropic wet etching of a silicon (110) wafer were studied. A sample device with 19 microm wide (111) sidewalls was fabricated using a 220 microm thick silicon (110) wafer and potassium hydroxide solution. For what we believe to be the first time, x-ray reflection on the (111) sidewalls was detected in the angular response measurement. Compared to ray-tracing simulations, the surface roughness of the sidewalls was estimated to be 3-5 nm, which is consistent with the atomic force microscope and the surface profiler measurements.

[Solid variant of aneurysmal bone cyst; report of a case]

We report a rare case of a solid variant of aneurysmal bone cyst (ABC) of the right 4th rib. A 29-year-old woman was admitted to our hospital for an abnormal shadow on chest X-ray. Chest computed tomography (CT) demonstrated the lesion mass to be located in the area of the right 4th rib. Bone scintigram revealed a hot spot in the right 4th rib. The right 4th rib was resected en bloc with the parietal pleura, and adjacent intercostal muscles via right anterior thoracotomy. Postoperative pathological evaluation was consistent with a solid variant of ABC.

[Thoracoscopic removal of bronchogenic cyst of the posterior mediastinum; report of a case]

A 15-year-old female was admitted to our hospital with an abnormal chest X-ray shadow in the left posterior mediastinum found at health screening. Magnetic resonance imaging (MRI) suggested that the cystic lesion contained a viscous liquid. The lesion was removed using a thoracoscope and diagnosed as bronchogenic cyst. Postoperative pathological evaluation was consistent with the initial diagnosis of bronchogenic cyst. This case illustrates the usefulness of thoracoscopic surgery for diagnosis and extirpation of bronchogenic cyst.

[Tuberculous abscess in the chest wall; report of a case]

A 72-year-old woman was admitted to our hospital with left chest pain. Chest computed tomography (CT) revealed an abscess in the left lateral chest wall. Bacterial examination of needle aspiration biopsy specimen from the chest wall abscess disclosed positive acid-fast bacilli. The size of chest wall abscess increased after initiation of antituberculous therapy with isoniazid, rifampicin, ethambutol hydrochloride and pyrazinamide, and therefore abscess drainage was subsequently performed. The lesion was resected after the abscess had diminished in size.

Footpad reaction induced by Neospora caninum tachyzoite extract in infected BALB/c mice

Little information is available regarding a delayed type hypersensitivity (DTH) reaction in neosporosis. In this study, we examined the elicitation of a DTH reaction in mice infected with Neospora caninum by inoculation of the footpad with tachyzoite antigens. The footpads of BALB/c mice infected with N. caninum and those of non-infected were injected with either the tachyzoite extract, or paraformaldehyde-fixed tachyzoites. In mice inoculated with N. caninum antigens on day 7 p.i. swelling peaked at 6h after injection of the tachyzoite extract. In mice inoculated on days 14, 28 and 56, swelling was observed between 6 and 72 h afterwards. Mice immunized with the tachyzoite extract plus adjuvant showed peak footpad swelling at 6h post injection, and the swelling had decreased at 24h or later. In contrast, mice injected before infection showed no specific swelling. In sections of footpads injected with the tachyzoite extract, exudate had accumulated at 6h post injection and clusters of infiltrated lymphocytes were observed at 48 h post injection. In mice administered anti-CD4+ cell monoclonal antibodies swelling had decreased at 24h post injection of the extract. These results indicate that mice infected with N. caninum produce a DTH reaction, which is a good indicator of the development of type 1 immune responses.

Toxoplasma gondii Does Not Persist In Goldfish (Carassius auratus)

Recent reports of toxoplasmosis in marine mammals raise concern that cold-blooded marine animals are a potential source of Toxoplasma gondii infection. To examine the transmissibility of T. gondii to fish, we observed the development of T. gondii tachyzoites inoculated into oviduct epithelial cells of goldfish (Carassius auratus) microscopically in vitro. Further, the survival period of tachyzoites inoculated into goldfish muscle was bioassayed in mice and through PCR analysis. In cell cultures at 37 C, both RH and Beverley strains of T. gondii tachyzoites had penetrated into cells at 6 hr post inoculation, and were multiplying. In cell cultures at 33 C, many tachyzoites of both strains attached to the host cells, but no intracellular tachyzoites were observed at 24 hr post inoculation. In the T. gondii inoculated goldfish kept at 33 C, tachyzoite DNA was detected in the inoculated region on day 3, but not on day 7. When inoculated goldfish were kept at 37 C, live tachyzoites were seen at the inoculation site on day 3, but not on day 7. These results suggest that T. gondii does not persist in fish.