The development, use, and challenges of electromechanical tissue stimulation systems.

BACKGROUND: Tissue stimulations greatly affect cell growth, phenotype, and function, and they play an important role in modeling tissue physiology. With the goal of understanding the cellular mechanisms underlying the response of tissues to external stimulations, in vitro models of tissue stimulation have been developed in hopes of recapitulating in vivo tissue function. METHODS: Herein we review the efforts to create and validate tissue stimulators responsive to electrical or mechanical stimulation including tensile, compression, torsion, and shear. RESULTS: Engineered tissue platforms have been designed to allow tissues to be subjected to selected types of mechanical stimulation from simple uniaxial to humanoid robotic stain through equal-biaxial strain. Similarly, electrical stimulators have been developed to apply selected electrical signal shapes, amplitudes, and load cycles to tissues, lending to usage in stem cell-derived tissue development, tissue maturation, and tissue functional regeneration. Some stimulators also allow for the observation of tissue morphology in real-time while cells undergo stimulation. Discussion on the challenges and limitations of tissue simulator development is provided. CONCLUSIONS: Despite advances in the development of useful tissue stimulators, opportunities for improvement remain to better reproduce physiological functions by accounting for complex loading cycles, electrical and mechanical induction coupled with biological stimuli, and changes in strain affected by applied inputs.

The Role of the Aryl Hydrocarbon Receptor in Vascular Factors Related to Preeclampsia in a Smoking Mouse Model.

Smoking cigarettes is known to lower the risk of preeclampsia. The objective of this study is to evaluate the effect of smoking on the expression of soluble FMS-like tyrosine kinase-1 (sFlt-1), vascular endothelial growth factor (VEGF), and endoglin (sEng)-1 and the role of the aryl hydrocarbon receptor (AhR) in pregnant mice. We developed a smoking mouse model using a gas-filling system. One or two cigarettes per day were exposed to each of the five pregnant mice for five days a week throughout pregnancy. AhR agonist and antagonist were injected. Serum levels and expression in the placenta of sFlt-1, VEGF, and sEng-1 were analyzed and compared among the cigarette smoke and no-exposure groups after delivery. Compared to the no-smoke exposure group, the serum level of sFlt-1 was significantly decreased in the two-cigarette-exposed group (p < 0.001). When the AhR antagonist was added to the two-cigarette-exposed group, sFlt-1 levels were significantly increased compared to the two-cigarette group (p = 0.002). The levels of sFlt-1 in the AhR antagonist group did not change regardless of two-cigarette exposure (p = 0.064). With the AhR agonist, sFlt-1 decreased significantly compared to the control (p = 0.001) and AhR antagonist group (p = 0.002). The sFlt-1 level was significantly decreased after the injection of the AhR agonist compared to the control group (p = 0.001). Serum levels of VEGF were significantly decreased in the one-cigarette-exposed group compared to the control group; however, there was no difference between the control and the two-cigarette-exposed groups. The placental expression of sFlt-1, VEGF, and sEng were inconsistent. This study offers insights into the potential role of AhR on antiangiogenic sFlt-1 associated with preeclampsia. It may support the invention of a new treatment strategy for preeclampsia using AhR activation.

Gate Controlled Excitonic Emission in Quantum Dot Thin Films.

Formation of charged trions is detrimental to the luminescence quantum efficiency of colloidal quantum dot (QD) thin films as they predominantly undergo nonradiative recombination. In this regard, control of charged trion formation is of interest for both fundamental characterization of the quasi-particles and performance optimization. Using CdSe/CdS QDs as a prototypical material system, here we demonstrate a metal-oxide-semiconductor capacitor based on QD thin films for studying the background charge effect on the luminescence efficiency and lifetime. The concentration ratio of the charged and neutral quasiparticles in the QDs is reversibly controlled by applying a gate voltage, while simultaneous steady-state and time-resolved photoluminescence measurements are performed. Notably, the photoluminescence intensity is modulated by up to 2 orders of magnitude with a corresponding change in the effective lifetime. In addition, chip-scale modulation of brightness is demonstrated, where the photoluminescence is effectively turned on and off by the gate, highlighting potential applications in voltage-controlled electrochromics.

Consensus-based clustering and data aggregation in decentralized network of multi-agent systems.

Multi-agent systems are promising for applications in various fields. However, they require optimization algorithms that can handle large number of agents and heterogeneously connected networks in clustered environments. Planning algorithms performed in the decentralized communication model and clustered environment require precise knowledge about cluster information by compensating noise from other clusters. This article proposes a decentralized data aggregation algorithm using consensus method to perform COUNT and SUM aggregation in a clustered environment. The proposed algorithm introduces a trust value to perform accurate aggregation on cluster level. The correction parameter is used to adjust the accuracy of the solution and the computation time. The proposed algorithm is evaluated in simulations with large and sparse networks and small bandwidth. The results show that the proposed algorithm can achieve convergence on the aggregated data with reasonable accuracy and convergence time. In the future, the proposed tools will be useful for developing a robust decentralized task assignment algorithm in a heterogeneous multi-agent multi-task environment.

Telecommuting-related health outcomes during the COVID-19 pandemic in South Korea: a national population-based cross-sectional study.

BACKGROUND: Telecommuting has expanded greatly during the COVID-19 pandemic. Since the advent of remote working from home, there has been an ongoing controversy about the positive or negative health-related impact of telecommuting. This study aimed to investigate change in the occupational health risk in South Korean workers involved in telecommuting during the pandemic period compared to daily commuters. METHODS: A population-based cross-sectional study of South Korean workers using the secondary data from the 6th Korean Working Conditions Survey (2020-2021) was designed. A total of 12,354 white-collar wage employees were selected as the study sample. Telecommuting, depression, anxiety, insomnia, fatigue, musculoskeletal pain, headache-eye strain, absenteeism, and presenteeism were measured by self-reported data. Multiple logistic regression models, including gender stratification analysis, were used to estimate the adjusted odds ratio (AOR) with a 95% confidence interval (CI) for the health outcomes of telecommuters. RESULTS: Among the study population, 338 males and 318 females were reported to be telecommuters. The entirely adjusted regression model showed a positive association between telecommuting and anxiety (AOR = 2.82; 95% CI, 1.93-4.10), insomnia (AOR = 1.93; 95% CI, 1.27-2.92), fatigue (AOR = 1.76; 95% CI, 1.30-2.37), musculoskeletal pain (AOR = 1,76; 95% CI, 1.33-2.32), headache-eye strain (AOR = 1.94; 95% CI, 1.48-2.54), presenteeism (AOR = 1.66; 95% CI, 1.20-2.28) respectively. Gender difference was identified in that only female telecommuters had a higher risk of depression (AOR = 1.62; 95% CI, 1.04-2.53) and insomnia (AOR = 2.07; 95% CI, 1.26-3.41) than daily commuters in the adjusted model. CONCLUSION: Telecommuting was significantly associated with an increased risk of various health problems among South Korean workers and females were identified as a more vulnerable group. Although further research is required to ascertain the causal relationship, public health intervention should be considered to prevent the negative effects of telecommuting.

Humidity-Tolerant Moisture-Driven Energy Generator with MXene Aerogel-Organohydrogel Bilayer.

Free-standing and film-type moisture-driven energy generators (MEGs) that harness the preferential interaction of ionized moisture with hydrophilic materials are interesting because of their wearability and portability without needing a water container. However, most such MEGs work in limited humidity conditions, which provide a substantial moisture gradient. Herein, we present a high-performance MEG with sustainable power-production capability in a wide range of environments. The bilayer-based device comprises a negatively surface-charged, hydrophilic MXene (Ti3C2Tx) aerogel and polyacrylamide (PAM) ionic hydrogel. The preferential selection on the MXene aerogel of positive charges supplied from the salts and water in the hydrogel is predicted by the first-principle simulation, which results in a high electric output in a wide relative humidity range from 20% to 95%. Furthermore, by replacing the hydrogel with an organohydrogel of PAM that has excellent water retention and structural stability, a device with long-term electricity generation is realized for more than 15 days in a broad temperature range (from -20 to 80 °C). Our MXene aerogel MEGs connected in series supply sufficient power for commercial electronic components in various outdoor environments. Moreover, an MXene aerogel MEG works as a self-powered sensor for recognizing finger bending and facial expression.

Working From Home, Work-Life Balance, and Depression/Anxiety Among Korean Workers in the COVID-19 Pandemic Period: A Mediation Analysis.

OBJECTIVE: We aimed to investigate the association between working from home (WFH), depression/anxiety, and work-family conflict (WFC) among Korean workers during the COVID-19 pandemic. METHODS: We surveyed a total of 1074 workers online. Depression and anxiety were measured using the Centre for Epidemiologic Studies Depression Scale (CES-D) and Beck Anxiety Inventory (BAI). Mediating effects of WFC on the relationship between WFH and depression/anxiety were examined. RESULTS: The WFH group had higher depression and anxiety scores than the daily commuting group. As WFC increased, the CES-D and BAI scores also increased. A possible mediating effect of WFC on the relationship between WFH and high CES-D and BAI scores was found. CONCLUSION: We observed a significant difference in depression/anxiety between WFH and daily commute workers, which was mediated by WFC, especially for young, child-growing, and precarious workers.

Can deep learning reduce the time and effort required for manual segmentation in 3D reconstruction of MRI in rotator cuff tears?

BACKGROUND/PURPOSE: The use of MRI as a diagnostic tool has gained popularity in the field of orthopedics. Although 3-dimensional (3D) MRI offers more intuitive visualization and can better facilitate treatment planning than 2-dimensional (2D) MRI, manual segmentation for 3D visualization is time-consuming and lacks reproducibility. Recent advancements in deep learning may provide a solution to this problem through the process of automatic segmentation. The purpose of this study was to develop automated semantic segmentation on 2D MRI images of rotator cuff tears by using a convolutional neural network to visualize 3D models of related anatomic structures. METHODS: MRI scans from 56 patients with rotator cuff tears (T2 Linear Coronal MRI; 3.0T, 512 mm × 512 mm, and 2.5-mm slice thickness) were collected. Segmentation masks for the cuff tendon, muscle, bone, and cartilage were obtained by four orthopedic shoulder surgeons, and these data were revised by a shoulder surgeon with more than 20 years' experience. We performed 2D and 3D segmentation using nnU-Net with secondary labels for reducing false positives. Final validation was performed in an external T2 MRI dataset (10 cases) acquired from other institutions. The Dice Similarity Coefficient (DSC) was used to validate segmentation quality. RESULTS: The use of 3D nnU-Net with secondary labels to reduce false positives achieved satisfactory results, even with a limited amount of data. The DSCs (mean ± SD) of the cuff tendon, muscle, bone, and cartilage in the internal test set were 80.7% ± 9.7%, 85.8% ± 8.6%, 97.8% ± 0.6%, and 80.8% ± 15.1%, respectively. In external validation, the DSC of the tendon segmentation was 82.74±5.2%. CONCLUSION: Automated segmentation using 3D U-Net produced acceptable accuracy and reproducibility. This method could provide rapid, intuitive visualization that can significantly facilitate the diagnosis and treatment planning in patients with rotator cuff tears.

Association between sickness presenteeism and depressive symptoms in Korean workers during the COVID-19 pandemic: A cross-sectional study.

BACKGROUND: During the COVID-19 pandemic, Korean workers have reported various types of sickness presenteeism (SP: continuing to attend work during illness). Understanding SP through mental health perspectives will help to make practical strategy for better working conditions. We examined the association between SP and depression among Korean workers during the COVID-19 pandemic in relation with the socioeconomic and lifestyle factors. METHODS: Data from the 2020 Korean Community Health Survey were used as a representative nationwide sample dataset. We surveyed the experience of depression in the last two weeks from individuals who worked more than a week recently. We investigated the associations between SP and depressive symptoms. Depressive symptoms were scored using the Patient Health Questionnaire-9 (PHQ-9). Logistic regression analysis was performed to examine the significance of the associations. RESULTS: Analysis of the data obtained from 84,514 participants revealed that 1700 (2.2 %) participants reported experiencing depressive symptoms in 2020. Employees with SP showed higher association with depressive symptoms than employers or self-employed individuals (OR = 2.18, 95 % CI: 1.85, 2.56 among employees vs. OR = 1.76, 95 % CI: 1.29, 2.40 among employers or self-employed individuals). CONCLUSION: SP has become more prominent during the COVID-19 pandemic. A protective strategy against SP among vulnerable workers is necessary for a healthier and safer society.

COVID-19 and vaccination during pregnancy: a systematic analysis using Korea National Health Insurance claims data.

OBJECTIVE: This study systematically analyzed coronavirus disease 2019 (COVID-19) and vaccination details during pregnancy by using the national health insurance claims data. METHODS: Population-based retrospective cohort data of 12,399,065 women aged 15-49 years were obtained from the Korea National Health Insurance Service claims database between 2019 and 2021. Univariate analysis was performed to compare the obstetric outcomes of pregnant women (ICD-10 O00-O94) and their newborns (ICD-10 P00-P96) with and without COVID-19. Univariate analysis was also performed to compare the age and obstetric outcomes of pregnant women receiving different types of vaccines. RESULTS: The percentage of pregnant women with COVID-19 during pregnancy was 0.11%. Some obstetric outcomes of pregnant women with COVID-19, including the rates of preterm birth or cesarean delivery, were significantly better than those of pregnant women without COVID-19. The rate of miscarriage was higher in pregnant women with COVID-19 than without COVID-19. However, the outcomes of newborns of women with and without COVID-19 were not significantly different. Regarding vaccination type, obstetric outcomes of pregnant women appeared to be worse with the viral vector vaccine than with the mRNA vaccine. CONCLUSION: To the best of our knowledge, this is the first study to systematically analyze COVID-19 and vaccination details during pregnancy using the national health insurance claims data in Korea. The obstetric outcomes in pregnant women with and without COVID-19 and their newborns were similar.

Correction: Kim et al. The Value of Posterior Cervical Angle as a Predictor of Vaginal Delivery: A Preliminary Study. Diagnostics 2021, 11, 1977.

In the original publication [...].

Wireless Stand-Alone Trimodal Interactive Display Enabled by Direct Capacitive Coupling.

With recent advances in interactive displays, the development of a stand-alone interactive display with no electrical interconnection is of great interest. Here, a wireless stand-alone interactive display (WiSID), enabled by direct capacitive coupling, consisting of three layers: two in-plane metal electrodes separated by a gap, a composite layer for field-induced electroluminescence (EL) and inverse piezoelectric sound, and a stimuli-responsive layer, from bottom to top, is presented. Alternating current power necessary for field-induced EL and inverse piezoelectric sound is wirelessly transferred from a power unit, with two in-plane electrodes remotely separated from the WiSID. The unique in-plane power transfer through the stimuli-sensitive polar bridge allows stand-alone operation of the WiSID, making it suitable for the wireless dynamic monitoring of medical fluids. Moreover, a haptic wireless stand-alone trimodal interactive display mounted on a human finger is demonstrated, whereby touch is wirelessly displayed in various outputs of EL, inverse piezoelectric sound, and tactile vibration, making it suitable for a wireless three-mode smart braille display.

The Value of Posterior Cervical Angle as a Predictor of Vaginal Delivery: A Preliminary Study.

Accurate prediction of failure to progress and rapid decision making regarding the mode of delivery can improve pregnancy outcomes. We examined the value of sonographic cervical markers in the prediction of successful vaginal delivery beyond 34 weeks of gestation. A retrospective chart review was carried out. Medical information of singleton gestations delivered at a single center from 1 July 2019 to 30 August 2020 was collected. Transvaginal sonographic records of cervical length, anterior and posterior cervical angles, and cervical dilatation were obtained and re-measured. The value of these markers and clinical characteristics of mother and baby on vaginal delivery were investigated and compared to women who underwent cesarean section. A total of 90 women met the inclusion criteria. The rate of vaginal delivery was 75.6%. There were no differences found in terms of maternal age, rate of abortion, induction of labor, premature rupture of membranes, preterm labor, hypertension, diabetes, cervical length, and neonatal sex and weight. The prediction of vaginal delivery was provided by parity, maternal body mass index, and posterior cervical angle. The area under the receiver operating characteristic curve for prediction of vaginal delivery was 0.667 (95% CI 0.581-0.864, p = 0.017) for the posterior cervical angle, with a cutoff of 96.5°. Regression analysis revealed a posterior cervical angle ≥96.5° in the prediction of vaginal delivery (adjusted odds ratio: 6.24; 95% confidence interval: 1.925-20.230, p = 0.002). Posterior cervical angle ≥96.5° is associated with successful vaginal delivery. It is simple and easy to measure and can be useful in determining the mode of delivery.

The association between effort-reward imbalance, work-life balance and depressive mood in Korean wage workers: The 4th Korean Working Conditions Survey.

BACKGROUND: This study was conducted to determine the association between work-life (WL) balance, effort-reward (ER) imbalance, and depressive mood in Korean wage workers when 2 models were considered simultaneously. METHODS: We analyzed 26,014 Korean workers including 13,471 men and 12,543 women from the 4th Korean Working Conditions Survey data. Multiple logistic regression was used to analyze the association between WL, ER status, and the depressive mood of Korean workers. We classified the subjects into a total of 4 groups as follows. Group 1: WL and ER status are both "balanced", group 2: WL status is "imbalanced" and ER status is "balanced", group 3: WL status is "balanced" and the ER status is "imbalanced", group 4: WL and ER status are both "imbalanced." RESULTS: We found significantly increased odds ratios (ORs) for depressive mood in groups 2, 3, and 4 compared with group 1 after adjusting for the general and occupational characteristics of the subjects in both men and women. We also found that the trend of ORs increased gradually from groups 2 to 4 compared with group 1 in both men and women; group 2: OR: 1.23 (95% confidence interval [CI]: 1.12-1.35), group 3: OR: 1.40 (95% CI: 1.27-1.55), group 4: OR: 1.99 (95% CI: 1.74-2.28) compared with group 1 in men; group 2: OR: 1.28 (95% CI: 1.15-1.42), group 3: OR: 1.45 (95% CI: 1.31-1.59), group 4: OR: 2.04 (95% CI: 1.76-2.36) compared with group 1 in women. CONCLUSIONS: As a result, we found the association between imbalanced WL, ER status, and depressive mood in Korean workers using 2 models simultaneously. It is important to provide a balanced WL and ER condition to improve the mental health of workers.

The association between non-regular work patterns and insomnia among Korean wage workers: the fifth Korean working condition survey.

BACKGROUND: Non-regular workers are steadily increasing on account of improving corporate productivity. They are classified as non-permanent, part-time, or non-typical workers. Non-regular work has a negative impact on workers' physical and mental health. This study analyzed the relationship between non-permanent, part-time and non-typical work and insomnia among Korean wage workers, and investigated the differences and interactions between different work patterns. METHODS: The Fifth Korean Working Conditions Survey was used in this study. Non-regular work patterns were classified into 7 types: type 1, sole non-permanent; type 2, sole part-time; type 3, sole non-typical; type 4, part-time-non-typical; type 5, non-permanent-non-typical; type 6, non-permanent-part-time; type 7, all inclusive. Insomnia was measured on a scale from "normal sleep" to "insomnia" based on the 3-item Minimal Insomnia Symptom Scale. Multiple logistic regression was used to analyze the association between non-regular work patterns and insomnia among wage workers. RESULTS: After multivariate adjustment, a significantly increased odds ratio (OR) for insomnia was found in types 1, 2, 3, 4, 5, 6, and 7 of non-regular work patterns compared to regular work patterns. After stratification for shift and night work, the OR of the group with shift and night work was higher than that of the group without shift and night work. CONCLUSIONS: Insomnia was significantly associated with non-regular work patterns. This association was prominent in workers with shifts and night work. This finding suggests that proper work patterns may be needed to reduce the risk of insomnia among Korean wage workers and workers who initially had insomnia should consider these results before placement.

Bird-Inspired Self-Navigating Artificial Synaptic Compass.

Extrasensory neuromorphic devices that can recognize, memorize, and learn stimuli imperceptible to human beings are of considerable interest in interactive intelligent electronics research. This study presents an artificially intelligent magnetoreceptive synapse inspired by the magnetocognitive ability used by birds for navigation and orientation. The proposed synaptic platform is based on arrays of ferroelectric field-effect transistors with air-suspended magneto-interactive top-gates. A suspended gate of an elastomeric composite with superparamagnetic particles laminated with an electrically conductive polymer is mechanically deformed under a magnetic field, facilitating control of the magnetic-field-dependent contact area of the suspended gate with an underlying ferroelectric layer. The remanent polarization of the ferroelectric layer is electrically programmed with the deformed suspended gate, resulting in analog conductance modulation as a function of the magnitude, number, and time interval of the input magnetic pulses. The proposed extrasensory magnetoreceptive synapse may be used as an artificially intelligent synaptic compass that facilitates barrier-adaptable navigation and mapping of a moving object.

Novel Dual-Curing Process for a Stereolithographically Printed Part Triggers a Remarkably Improved Interlayer Adhesion and Excellent Mechanical Properties.

Stereolithography (SL) is widely used because of its numerous advantages over other three-dimensional printing (3DP) techniques. However, SL is a layer-by-layer process, where interlayer adhesion between adjacent layers becomes more brittle than the intralayer adhesion, common to all 3DP process. Here, we report a facile method to strengthen the interlayer adhesion for SL. By the addition of monomers with thermally curable functional groups (epoxy or hydroxyl groups), thermal post-curing induces chemical reactions between them in adjacent layers after the photoinitiated printing process. It leads to fully 3D cured objects with enhanced interlayer bonding and substantially improved mechanical properties, but not a significant change in the dimensional stability. This approach can expand the use of 3DP techniques in load-bearing applications that require mechanically robust printed objects with precise dimensions.

Long-Living Anions Could Dramatically Change the Overall Physical Properties of a Polyamide (Nylon 6) Synthesized by a Novel Process.

We devised a novel strategy of two-stage anionic polymerization of (ε-caprolactam) in a twin screw extruder to control the generation of branched structures. Long-living anions of nylon 6 prepared in the first extrusion gave rise to a change in the molecular structure when they interacted with diamine added during the second extrusion. It has been found that the transfer of living anions between functional molecules having the same anion-forming groups affects the structural change of the resulting polymer molecule. The variation in chain structure has resulted in dramatic changes in the physical and dynamic properties of the polymer despite changes in molecular weight of less than 2 without forming a network structure. Tensile elongation and toughness at the optimum concentration of the additive were increased by 5 and 10 times, respectively, which was enough for the resulting polymer to be classified as a super-tough nylon without a toughener. It can be widely used as a matrix polymer for diverse composite materials.

Effect of Diamine Addition on Structural Features and Physical Properties of Polyamide 6 Synthesized by Anionic Ring-Opening Polymerization of ε-Caprolactam.

Synthesis of ε-caprolactam in a twin screw extruder by anionic ring-opening polymerization was successfully carried out to prepare a novel nylon 6 (polyamide 6 (PA6)) containing a small amount of diamine moiety. The produced PA6 shows a remarkable improvement of the physical properties (mechanical properties as well as rheological properties). Added diamine molecules led to some structural changes in the synthesized PA6. The molar ratio of the additive (diamine) to the initiator appeared to be optimum at ca. 0.1. Although the molar mass of the PA6 has not changed significantly, less than twice the PA6 molar mass, the physical properties of the polymers produced have been markedly improved. The zero shear rate viscosity of the PA6 at the optimum diamine concentration appeared to be increased by almost 30 times that of the pure PA6. We have attributed this remarkable increase in viscosity to structural changes (branching formation during synthesis) and increased molar mass. The storage modulus at a low shear rate increased more than 100 times that of the pure PA6, but the loss modulus increased only 10-fold. This indicates that the elastic properties dominated due to the enhanced chain entanglements. In addition, the mechanical properties were significantly improved at the optimal amount of diamine reagent concentration. The elongation at break for the sample with optimum diamine addition was increased to twice that of neat PA6, whereby the tensile toughness was also doubled. Produced PA6 has a merit of processibility in the extrusion process such as a blow molding process in which stability against sagging under gravity is required and other processes in which elongational properties dominate.

Pure Piezoelectricity Generation by a Flexible Nanogenerator Based on Lead Zirconate Titanate Nanofibers.

Lead zirconate titanate (PbZr0.52Ti0.48O3, PZT) alloys have been extensively studied to be used for piezoelectric nanogenerators to harvest energy from mechanical motions. In this study, PZT nanofiber-based nanogenerators were fabricated to test their true piezoelectric performance without the triboelectric effect. Aligned PZT nanofibers were fabricated by a sol-gel electrospinning process. The thickness, area, and orientation of the PZT textile made by electrospinning a PZT solution onto multipair metal wires or metal mesh were controlled to form a composite textile. After the calcination, the PZT textile mixed with polydimethylsiloxane was placed between two flexible indium-doped tin oxide-polyethylene naphthalate substrates. The performance parameters of the nanogenerators were investigated under the bending motion, which excludes the triboelectric effect. An assembled nanogenerator of an area of 8 cm2 and a thickness of 80 µm could generate an electrical output voltage of 1.1 V and a current of 1.4 µA under the bending strain. The piezoelectric voltage depended on the thickness of the PZT textile, whereas the piezoelectric current depended on both the thickness and the area of the PZT textile. The electrical performance of the device was significantly affected by the orientation of the PZT fiber and the bending direction. The output voltage and the output current were strain-dependent, whereas the total integrated charge was independent of the strain rate. The properties of the flexible nanogenerator could be quantified to verify the pure piezoelectric performance of the device.