Fabrication of Piezo-Resistance Composites Containing Thermoplastic Polyurethane/Hybrid Filler Using 3D Printing.

In this study, 3D-printable flexible piezoresistive composites containing various amounts of cilia-like hybrid fillers were developed. In the hybrid fillers, micro-scale Cu particles with a 0D structure may allow them to easily disperse into the flexible TPU matrix. Furthermore, nanoscale multi-walled carbon nanotubes (MWCNTs) with a high aspect ratio, present on the surface of the Cu particles, form an electrical network when the polymer matrix is strained, thus providing good piezoresistive performance as well as good flowability of the composite materials. With an optimal hybrid filler content (17.5 vol.%), the 3D-printed piezoresistive composite exhibits a gauge factor of 6.04, strain range of over 20%, and durability of over 100 cycles. These results highlight the potential applications of piezoresistive pressure sensors for health monitoring, touch sensors, and electronic skin.

Modeling and performance analysis of an improved movement-based location management scheme for packet-switched mobile communication systems.

One of the key technologies to support mobility of mobile station (MS) in mobile communication systems is location management which consists of location update and paging. In this paper, an improved movement-based location management scheme with two movement thresholds is proposed, considering bursty data traffic characteristics of packet-switched (PS) services. The analytical modeling for location update and paging signaling loads of the proposed scheme is developed thoroughly and the performance of the proposed scheme is compared with that of the conventional scheme. We show that the proposed scheme outperforms the conventional scheme in terms of total signaling load with an appropriate selection of movement thresholds.

A QoS aware resource allocation strategy for 3D A/V streaming in OFDMA based wireless systems.

Three-dimensional (3D) video is expected to be a "killer app" for OFDMA-based broadband wireless systems. The main limitation of 3D video streaming over a wireless system is the shortage of radio resources due to the large size of the 3D traffic. This paper presents a novel resource allocation strategy to address this problem. In the paper, the video-plus-depth 3D traffic type is considered. The proposed resource allocation strategy focuses on the relationship between 2D video and the depth map, handling them with different priorities. It is formulated as an optimization problem and is solved using a suboptimal heuristic algorithm. Numerical results show that the proposed scheme provides a better quality of service compared to conventional schemes.

The Relationships Among Health Literacy, Illness Perception, and Diabetes Self-Care in Korean-Speaking Immigrants With Diabetes.

Diabetes self-care is explained as an illness-related coping behavior. Health literacy is an important predictor in self-care behaviors. However, little is known about their association with illness perception in Korean immigrants with diabetes. This study aimed to examine the relationships among health literacy, illness perception, and diabetes self-care in Korean-speaking immigrants with diabetes. This cross-sectional study was conducted in 2020. A convenience sample of 52 Korean adults with diabetes in Dallas-Fort Worth areas completed a survey. Data were analyzed using SPSS (version 25) with statistical significance at α < .05. The mean of health literacy was high (11.1, SD = 1.1, ranges 0-12). There were no statistically significant associations between health literacy, illness perception, and diabetes self-care. Language barriers are considered a literacy issue, but health literacy and limited English proficiency must be approached differently by health care providers.

Modeling and analysis of an energy-efficient mobility management scheme in IP-based wireless networks.

An energy-efficient mobility management scheme in IP-based wireless networks is proposed to reduce the battery power consumption of mobile hosts (MHs). The proposed scheme manages seven MH states, including transmitting, receiving, attention/cell-connected, attention/paging area(PA)-connected, idle, off/attached, and detached states, to efficiently manage battery power, radio resources, and network load. We derive the stationary probabilities and steady state probabilities of the seven MH states for the proposed scheme in IP-based wireless networks in compact form. The effects of various input parameters on MH steady state probabilities and power consumption are investigated in the proposed scheme compared to the conventional scheme. Network costs such as cell updates, PA updates, binding-lifetime-based registrations, and paging messages are analyzed in the proposed and conventional schemes. The optimal values of PA size and registration interval are derived to minimize the network cost of the proposed scheme. The combined network and power costs are investigated for the proposed and conventional schemes. The results provide guidelines to select the proper system parameters in IP-based wireless networks.

Coexistence of WiFi and WiMAX systems based on PS-request protocols.

We introduce both the coexistence zone within the WiMAX frame structure and a PS-Request protocol for the coexistence of WiFi and WiMAX systems sharing a frequency band. Because we know that the PS-Request protocol has drawbacks, we propose a revised PS-Request protocol to improve the performance. Two PS-Request protocols are based on the time division operation (TDO) of WiFi system and WiMAX system to avoid the mutual interference, and use the vestigial power management (PwrMgt) bit within the Frame Control field of the frames transmitted by a WiFi AP. The performance of the revised PS-Request protocol is evaluated by computer simulation, and compared to those of the cases without a coexistence protocol and to the original PS-Request protocol.

Gender Differences in Parental Impact on Problematic Smartphone Use among Korean Adolescents.

This study aimed to examine the effective parental impact in preventing problematic smartphone use in adolescents by identifying the parent-related factors. A secondary analysis of cross-sectional data from a Korean national survey was conducted. Data from 2758 male and 2419 female adolescents, aged 10 to 19 years, were analyzed; the respondents were divided into normal and risk groups based on their standardized smartphone addiction diagnostic scale scores. Parent-related factors of smartphone addiction were analyzed using a logistic regression model. Among both male and female adolescents, mobile messenger usage, and family environment emerged as significant predictors of problematic smartphone use. In addition, for male adolescents, smartphone use frequency and parent's awareness of content use were significant predictors. The findings indicated the importance of parental roles in preventing problematic smartphone use in adolescents. Parents should create a healthy family environment by avoiding smartphone overuse and modeling the appropriate usage of smartphones.

Fast-food meal reduces peripheral artery endothelial function but not cerebral vascular hypercapnic reactivity in healthy young men.

Consumption of a representative fast-food meal (FFMeal) acutely impairs peripheral conduit artery vascular function; however, the effect on cerebral vascular function remains unknown. This study tested the hypothesis that a FFMeal would impair cerebral vascular function as indexed by an attenuated increase in cerebral vascular conductance (CVCI) in the middle cerebral artery (MCA) during a hypercapnic challenge. Ten healthy men (age: 24 ± 3 years, BMI: 24.3 ± 3.8 kg/m2 ) were studied under two conditions; a standardized FFMeal (990 kcals, 50% fat, 36% carbohydrate, 14% protein, and 2120 mg sodium) and a fasting control condition. Basal hemodynamics, cerebral vasomotor reactivity (CVMR), and brachial artery flow-mediated dilation (BA FMD) were completed after an overnight fast (Pre) and again 2 h and 4 h later both days. To assess CVMR, subjects rebreathed from a 5-L bag while MCA velocity (MCAVmean ) was measured using transcranial Doppler (TCD) ultrasound and converted into CVCI (MCAVmean /mean arterial pressure). Peripheral artery endothelial function was assessed via BA FMD following a standard 5-min occlusion protocol. As expected, BA FMD was reduced at 2 h (Pre: 6.6 ± 1.7% vs. 5.2 ± 1.8%, P = 0.01). However, despite significant impairment in BA FMD, neither peak CVCI%baseline nor CVMR was affected by the FFMeal (Control-Pre: 1.9 ± 1.1, 2 h: 2.1 ± 1.1, 4 h: 1.7 ± 1.1 ∆CVCI%·∆PET CO2-1 vs. FFMeal-Pre: 2.1 ± 1.1, 2 h: 2.2 ± 0.7, 4 h: 1.9 ± 0.9 ∆CVCI%·∆PET CO2-1 , time × condition P = 0.88). These results suggest that cerebral vascular reactivity to hypercapnia in healthy young men is not altered by an acute FFMeal.

Near-infrared spectroscopy detects age-related differences in skeletal muscle oxidative function: promising implications for geroscience.

Age is the greatest risk factor for chronic disease and is associated with a marked decline in functional capacity and quality of life. A key factor contributing to loss of function in older adults is the decline in skeletal muscle function. While the exact mechanism(s) remains incompletely understood, age-related mitochondrial dysfunction is thought to play a major role. To explore this question further, we studied 15 independently living seniors (age: 72 ± 5 years; m/f: 4/11; BMI: 27.6 ± 5.9) and 17 young volunteers (age: 25 ± 4 years; m/f: 8/9; BMI: 24.0 ± 3.3). Skeletal muscle oxidative function was measured in forearm muscle from the recovery kinetics of muscle oxygen consumption using near-infrared spectroscopy (NIRS). Muscle oxygen consumption was calculated as the slope of change in hemoglobin saturation during a series of rapid, supra-systolic arterial cuff occlusions following a brief bout of exercise. Aging was associated with a significant prolongation of the time constant of oxidative recovery following exercise (51.8 ± 5.4 sec vs. 37.1 ± 2.1 sec, P = 0.04, old vs. young, respectively). This finding suggests an overall reduction in mitochondrial function with age in nonlocomotor skeletal muscle. That these data were obtained using NIRS holds great promise in gerontology for quantitative assessment of skeletal muscle oxidative function at the bed side or clinic.

Isometric handgrip echocardiography: A noninvasive stress test to assess left ventricular diastolic function.

BACKGROUND: Cycle exercise echocardiography is a useful tool to "unmask" diastolic dysfunction; however, this approach can be limited by respiratory and movement artifacts. Isometric handgrip avoids these issues while reproducibly increasing afterload and myocardial oxygen demand. HYPOTHESIS: Isometric handgrip echocardiography (IHE) can differentiate normal from abnormal diastolic function. METHODS: First recruited 19 young healthy individuals (mean age, 24 ± 4 years) to establish the "normal" response. To extend these observations to a more at-risk population, we performed IHE on 17 elderly individuals (mean age, 72 ± 6 years) with age-related diastolic dysfunction. The change in the ratio of mitral valve inflow velocity to lateral wall tissue velocity (E/e'), a surrogate for left ventricular filling pressure, was used to assess the diastolic stress response in each group. RESULTS: In the young subjects, isometric handgrip increased heart rate and mean arterial pressure (25 ± 12 bpm and 26 ± 17 mmHg, respectively), whereas E/e' changed minimally (0.6 ± 0.9). In the elderly subjects, heart rate and mean arterial pressure were similarly increased with isometric handgrip (19 ± 16 bpm and 25 ± 11 mmHg, respectively), whereas E/e' increased more dramatically (2.3 ± 1.7). Remarkably, 11 of the 17 elderly subjects had an abnormal diastolic response (ΔE/e': 3.4 ± 1.1), whereas the remaining 6 elderly subjects showed very little change (ΔE/e': 0.3 ± 0.7), independent of age or the change in myocardial oxygen demand. CONCLUSIONS: IHE is a simple, effective tool for evaluating diastolic function during simulated activities of daily living.

Discrimination of the cultivar, growing region, and geographical origin of rice (Oryza sativa) using a mass spectrometer-based electronic nose.

The objective of this study was to discrimination the cultivar, growing region, and geographical origin of rice (Oryza sativa) using a mass spectrometry-based electronic nose (MSE-nose). The inside-needle dynamic extraction (INDEX) system was used to concentrate the samples for MSEnose, following which the ion fragment data obtained were used to perform discriminant function analysis. Discriminant functions 1 and 2 readily separated all 16 cultivars of rice sampled. It was also confirmed that MSE-nose could distinguish the region in which rice cv. Chucheong and Koshihikari were grown, likely due to variation in environmental factors, such as soil and climate. Finally, it was confirmed that MSE-nose could be used to detect the geographical origin of rice, discrimination Korea rice from Japanese rice. Therefore, this simple and rapid technique is of value for discriminating the cultivar, growing region, and geographical origin of rice.