628 research outputs found

    The Effects of Game Players’ Social Intelligence on Social Support and Psychosocial Problem Factors in a 2-Wave Longitudinal Study

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    Although digital gaming may be considered a social medium, no prior study has investigated how young players’ social intelligence affects their psychosocial problems (aggression, depression, loneliness, and stress) and social functioning (relationships with parents and peers). The primary aim of this study was to investigate the relations between social intelligence and psychosocial outcomes. Using data from 1364 online game players in Korea, we conducted a 2-wave longitudinal study at 6-month intervals for tracking the same person. The findings indicated that level of social intelligence was negatively related with all measures of adverse emotions and positively related with relationships with parents and peers over time. The findings and implications are discussed

    A Polynomial Digital Pre-Distortion Technique Based on Iterative Architecture

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    A digital predistortion (DPD) technique based on an iterative adaptation structure is proposed for linearizing power amplifiers (PAs). To obtain proper DPD parameters, a feedback path that converts the PA’s output to a baseband signal is required, and memory is also needed to store the baseband feedback signals. DPD parameters are usually found by an adaptive algorithm by using the transmitted signals and the corresponding feedback signals. However, for the adaptive algorithm to converge to a reliable solution, long feedback samples are required, which increases hardware complexity and cost. Considering that the convergence time of the adaptive algorithm highly depends on the initial condition, we propose a DPD technique that requires relatively shorter feedback samples. Specifically, the proposed DPD iteratively utilizes the short feedback samples in memory while keeping and using the DPD parameters found at the former iteration as the initial condition at the next iteration. Computer simulation shows that the proposed technique performs better than the conventional technique, as the former requires much shorter feedback memory than the latter

    Robust Digital Predistortion in Saturation Region of Power Amplifiers

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    This paper proposes a digital predistortion (DPD) technique to improve linearization performance when the power amplifier (PA) is driven near the saturation region. The PA is a non-linear device in general, and the nonlinear distortion becomes severer as the output power increases. However, the PA’s power efficiency increases as the PA output power increases. The nonlinearity results in spectral regrowth, which leads to adjacent channel interference, and degrades the transmit signal quality. According to our simulation, the linearization performance of DPD is degraded abruptly when the PA operates in its saturation region. To relieve this problem, we propose an improved DPD technique. The proposed technique performs on/off control of the adaptive algorithm based on the magnitude of the transmitted signal. Specifically, the adaptation normally works for small and medium signals while it stops for large signals. Therefore, harmful coefficient updates by saturated signals can be avoided. A computer simulation shows that the proposed method can improve the linearization performance compared with the conventional DPD method in highly driven PAs

    Bioinspired reversible hydrogel adhesives for wet and underwater surfaces

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    Stable and reversible adhesion to wet surfaces is challenging owing to water molecules at the contact interface. In this study, we develop a hydrogel-based wet adhesive, which can exhibit strong and reversible adhesion to wet and underwater surfaces as well as to dry surfaces. The remarkable wet adhesion of the hydrogel adhesive is realized based on a synergetic integration of bioinspired microarchitectures and water-friendly and water-absorbing properties of the polymeric hydrogel. Under dry conditions, the microstructured hydrogel adhesive exhibits strong van der Waals interaction-based adhesion, while under underwater conditions, it can maximize capillary adhesion. Consequently, the hydrogel adhesive exhibits remarkable adhesion strengths for dry, moist, and submerged substrates. Maximum normal and shear adhesion strengths of 423 and 384, 492 and 340, and 253 and 21 kPa are achieved with the hydrogel adhesive for dry, moist, and submerged substrates, respectively. Our results demonstrate that strong wet and underwater adhesion can be achieved only with the hydrogel-based adhesive with simple microscale architecture

    Continuous Tip Widening Technique for Roll-to-Roll Fabrication of Dry Adhesives

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    In this study, we reported continuous partial curing and tip-shaped modification methods for continuous production of dry adhesive with microscale mushroom-shaped structures. Typical fabrication methods of dry adhesive with mushroom-shaped structures are less productive due to the failure of large tips on pillar during demolding. To solve this problem, a typical pillar structure was fabricated through partial curing, and tip widening was realized through applying the proper pressure. Polyurethane acrylate was used in making the mushroom structure using two-step UV-assisted capillary force lithography (CFL). To make the mushroom structure, partial curing was performed on the micropillar, followed by tip widening. Dry adhesives with properties similar to those of typical mushroom-shaped dry adhesives were fabricated with reasonable adhesion force using the two-step UV-assisted CFL. This production technology was applied to the roll-to-roll process to improve productivity, thereby realizing continuous production without any defects. Such a technology is expected to be applied to various fields by achieving the productivity improvement of dry adhesives, which is essential for various applications

    DeepHealthNet: Adolescent Obesity Prediction System Based on a Deep Learning Framework

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    Childhood and adolescent obesity rates are a global concern because obesity is associated with chronic diseases and long-term health risks. Artificial intelligence technology has emerged as a promising solution to accurately predict obesity rates and provide personalized feedback to adolescents. This study emphasizes the importance of early identification and prevention of obesity-related health issues. Factors such as height, weight, waist circumference, calorie intake, physical activity levels, and other relevant health information need to be considered for developing robust algorithms for obesity rate prediction and delivering personalized feedback. Hence, by collecting health datasets from 321 adolescents, we proposed an adolescent obesity prediction system that provides personalized predictions and assists individuals in making informed health decisions. Our proposed deep learning framework, DeepHealthNet, effectively trains the model using data augmentation techniques, even when daily health data are limited, resulting in improved prediction accuracy (acc: 0.8842). Additionally, the study revealed variations in the prediction of the obesity rate between boys (acc: 0.9320) and girls (acc: 0.9163), allowing the identification of disparities and the determination of the optimal time to provide feedback. The proposed system shows significant potential in effectively addressing childhood and adolescent obesity

    Evaluation of Medicinal Categorization of Atractylodes japonica

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    Atractylodes rhizomes have been used as the herbal medicine “Changchul” or “Baekchul,” according to their clinical purpose, in Korea, China, and Japan. Among the Atractylodes species, the medicinal use of Atractylodes japonica has been controversial, as it is categorized as both Changchul and Baekchul in those countries, and, moreover, parts of the rhizome have been differently used, depending on age of the plant, in Korea. Chromatographic fingerprinting by using HPLC combined with chemometric analyses and internal transcribed spacer (ITS) sequencing analysis were conducted to classify and identify 34 crude drugs derived from Atractylodes rhizomes. The identification of the samples, authenticated by their morphological features as A. japonica Koidz. (Changchul and Baekchul), A. chinensis Koidz., and A. macrocephala Koidz., was confirmed as A. japonica, A. chinensis, and A. macrocephala by ITS sequencing. The results from chemometric analyses showed that the chemical components of the crude drugs from A. japonica were significantly different from those from A. macrocephala but were similar to those from A. chinensis. The analyses also suggested that the categorization by age of A. japonica as Changchul or Baekchul is not recommended. The results indicate that A. japonica should be categorized as “Changchul” and should not be further categorized by age

    Modulation of lignin biosynthesis for drought tolerance in plants

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    Lignin is a complex polymer that is embedded in plant cell walls to provide physical support and water protection. For these reasons, the production of lignin is closely linked with plant adaptation to terrestrial regions. In response to developmental cues and external environmental conditions, plants use an elaborate regulatory network to determine the timing and location of lignin biosynthesis. In this review, we summarize the canonical lignin biosynthetic pathway and transcriptional regulatory network of lignin biosynthesis, consisting of NAC and MYB transcription factors, to explain how plants regulate lignin deposition under drought stress. Moreover, we discuss how the transcriptional network can be applied to the development of drought tolerant plants

    A Pressure-Insensitive Self-Attachable Flexible Strain Sensor with Bioinspired Adhesive and Active CNT Layers

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    Flexible tactile sensors are required to maintain conformal contact with target objects and to differentiate different tactile stimuli such as strain and pressure to achieve high sensing performance. However, many existing tactile sensors do not have the ability to distinguish strain from pressure. Moreover, because they lack intrinsic adhesion capability, they require additional adhesive tapes for surface attachment. Herein, we present a self-attachable, pressure-insensitive strain sensor that can firmly adhere to target objects and selectively perceive tensile strain with high sensitivity. The proposed strain sensor is mainly composed of a bioinspired micropillar adhesive layer and a selectively coated active carbon nanotube (CNT) layer. We show that the bioinspired adhesive layer enables strong self-attachment of the sensor to diverse planar and nonplanar surfaces with a maximum adhesion strength of 257 kPa, while the thin film configuration of the patterned CNT layer enables high strain sensitivity (gauge factor (GF) of 2.26) and pressure insensitivity

    Pharmacokinetics of a telmisartan, amlodipine and hydrochlorothiazide fixed-dose combination: A replicate crossover study in healthy Korean male subjects

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    Purpose: To compare the tolerability and pharmacokinetic profiles of telmisartan, amlodipine, and hydrochlorothiazide (HCTZ) in a fixed-dose combination (FDC, test product) with a co-administered telmisartan/amlodipine FDC and HCTZ in a single-entity tablet (reference product)Methods: This was a single-dose, randomized, open-label, replicate crossover study conducted in healthy male Korean volunteers aged 19 – 50 years. Fasting randomized subjects received a newly developed test product (telmisartan/ amlodipine/HCTZ, 80/10/25 mg) or two tablets of Twynsta® (40/5 mg) and one tablet of HCTZ (25 mg) as reference products. After a washout period, each group replicated the exposure of the other group.Results: The AUClast (h•ng/mL) geometric mean was 3,194.87 and 3,273.77 for the telmisartan test and reference products, respectively; 329.92 and 315.13 for the amlodipine test and reference products; 1,203.98 and 1,150.86 for the HCTZ test and reference products, respectively. The geometric mean of Cmax (ng/mL) was 543.04 and 497.81 for the telmisartan test and reference products, respectively; 7.74 and 7.34 for the amlodipine test and reference products; 218.71 and 184.39 for the HCTZ test and reference products, respectively. For telmisartan, the 90 % CI of GMRs of AUClast (h•ng/mL) and Cmax (ng/mL) were 0.9414 – 1.0496 and 1.0246 – 1.2792, respectively; the coefficient of variation (CV) of telmisartan Cmax was 41.96 %.Conclusion: A formulated FDC tablet containing a telmisartan/amlodipine/HCTZ combination (80/10/25mg) was bioequivalent to a co-administrated commercially available telmisartan/amlodipine combination and HCTZ tablets at equivalent concentrations.Keywords: Fixed-dose combination, Hypertension, Telmisartan, Amlodipine besylate, Hydrochlorothiazide, Pharmacokinetic
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