Incidence rate and predictors of recurrent aneurysms after clipping: long-term follow-up study of survivors of subarachnoid hemorrhage.

Recurrent aneurysms are a major cause of re-aneurysmal subarachnoid hemorrhage (aSAH), but information on long-term clip durability and predictors is insufficient. This study aimed to present the incidence rate of > 10 years and investigate predictors of a recurrent aneurysm in aSAH survivors. We included 1601 patients admitted with aSAH and treated by microsurgical clipping between January 1993 and May 2010. Of these patients, 435 aSAH survivors were included in this study (27.2%). The total follow-up time was 5680.9 patient-years, and the overall incidence rate was 0.77% per patient-year. The cumulative probability of recurrence without residua and regrowth of the neck remnant was 0.7% and 13.9% at 10 years, respectively. Neck remnant (hazard ratio [HR], 10.311; 95% confidence interval [CI], 5.233-20.313) and alcohol consumption over the moderate amount (HR, 3.166; 95% CI, 1.313-7.637) were independent risk factors of recurrent aneurysm. Current smoking and multiplicity at initial aSAH presentation were significant factors in a univariate analysis. Furthermore, de novo intracranial aneurysms (DNIAs) were more common in the recurrent group than in the non-recurrent group (40.9% vs. 11.5%, P < 0.001). In the present study, we noted the long-term clip durability and predictor of recurrence after microsurgical clipping. These findings can assist clinicians in identifying patients at a high risk of recurrent aneurysm and recommending selective long-term surveillance after microsurgical clipping.

Flow diverter for the treatment of large (> 10 mm) vertebral artery dissecting aneurysms.

OBJECTIVE: To evaluate the outcomes of flow-diverting device (FDD) treatment for large vertebral artery dissecting aneurysms (VADAs). METHODS: This retrospective study evaluated 12 patients with 12 VADAs who were treated using FDD between 2013 and 2020. Clinical and radiographic data, including procedure-related complications and clinical outcomes assessed using the modified Rankin Scale (mRS) at the time of the last follow-up, were collected and reviewed. RESULTS: All 12 patients had unruptured aneurysms. There were 3 (25%) female and 9 (75%) male patients, and the mean patient age was 54.6 years. The mean size of the aneurysm was 15.9 ± 4.8 mm. The mean follow-up duration was 15.8 months. Single FDD without additional coils was used in all patients. One patient underwent second-line treatment with FDD for recurrence of large VADA after stent-assisted coiling. Immediate follow-up angiography after placement of the FDD demonstrated intra-aneurysmal contrast stasis. There were 2 (17%) patients who had peri-procedural stroke. Angiography at the 6-month follow-up in 10 patients showed favorable occlusion (OKM grade C3 + D). A total of 11 (92%) patients had good clinical outcome (modified Rankin Scale ≤ 2) at the last follow-up. No re-treatment or delayed aneurysm rupture occurred during the follow-up period. CONCLUSIONS: Reconstructive technique with FDD is a feasible and effective modality for the treatment of large VADAs, showing favorable occlusion rate and clinical outcome.

Ruptured Infundibular dilatation of the posterior communicating artery.

OBJECTIVE: An infundibulum of the posterior communicating artery (PcomA) or infundibular dilatation (ID) is considered to be a benign anatomical variant. However, some evidence suggests that ID is a pre-aneurysmal state. This case series presents cases of ruptured IDs and aneurysms originating from the IDs. METHODS: Between April 2002 and June 2020, 1337 patients were treated for aneurysmal subarachnoid hemorrhage (SAH). Among them, 7 patients with ruptured PcomA IDs were identified. Rupture IDs of the PcomA were categorized into 1) direct rupture of IDs, and 2) rupture of aneurysms originating from IDs. The clinical and radiographic factors were retrospectively reviewed. RESULTS: Two patients experienced direct rupture of IDs, while the other 5 patients presented with ruptured aneurysms originating from IDs. The 2 patients with direct rupture of IDs at presentation were relatively younger (< 50 years), while the other 5 patients with ruptured aneurysms originating from IDs were over 70 and had a history of aneurysmal SAH due to other intracranial aneurysms. Ruptured IDs were treated with microsurgery or endovascular treatment. There were no complications related to the procedure for securing ruptured IDs. Five (71.4%) patients showed favorable outcomes. One patient with initial Hunt and Hess grade 4 died due to initial brain damage with cerebral vasospasm and medical complications. CONCLUSIONS: ID of the PcomA rarely causes SAH with or without aneurysm formation. Thus, patients with IDs of the PcomA should be carefully followed up for a long period, especially those with a history of aneurysmal SAH.

Long-term health and germline transmission in transgenic cattle following transposon-mediated gene transfer.

BACKGROUND: Transposon-mediated, non-viral gene delivery is a powerful tool for generating stable cell lines and transgenic animals. However, as multi-copy insertion is the preferred integration pattern, there is the potential for uncontrolled changes in endogenous gene expression and detrimental effects in cells or animals. Our group has previously reported on the generation of several transgenic cattle by using microinjection of the Sleeping Beauty (SB) and PiggyBac (PB) transposons and seeks to explore the long-term effects of this technology on cattle. RESULTS: Transgenic cattle, one female (SNU-SB-1) and one male (SNU-PB-1), reached over 36 months of age with no significant health issues and normal blood parameters. The detection of transgene integration and fluorescent signal in oocytes and sperm suggested the capacity for germline transmission in both of the founder animals. After natural breeding, the founder transgenic cow delivered a male calf and secreted milk containing fluorescent transgenic proteins. The calf expressed green fluorescent protein in primary cells from ear skin, with no significant change in overall genomic stability and blood parameters. Three sites of transgene integration were identified by next-generation sequencing of the calf's genome. CONCLUSIONS: Overall, these data demonstrate that transposon-mediated transgenesis can be applied to cattle without being detrimental to their long-term genomic stability or general health. We further suggest that this technology may be usefully applied in other fields, such as the generation of transgenic animal models.

Road Surface Classification Using a Deep Ensemble Network with Sensor Feature Selection.

Deep learning is a fast-growing field of research, in particular, for autonomous application. In this study, a deep learning network based on various sensor data is proposed for identifying the roads where the vehicle is driving. Long-Short Term Memory (LSTM) unit and ensemble learning are utilized for network design and a feature selection technique is applied such that unnecessary sensor data could be excluded without a loss of performance. Real vehicle experiments were carried out for the learning and verification of the proposed deep learning structure. The classification performance was verified through four different test roads. The proposed network shows the classification accuracy of 94.6% in the test data.

Feasibility, Safety, and efficacy of endovascular treatment for M1 hilltop Aneurysms: A retrospective study.

OBJECTIVE: This retrospective study aimed to evaluate the feasibility, safety, and efficacy of endovascular treatment (EVT) for M1 hilltop aneurysms, a specific M1 segment subtype located at the highest point of the middle cerebral artery (MCA). METHODS: The study included 54 patients with M1 hilltop aneurysms who underwent EVT between December 2017 and [end date]. Treatment decisions were based on angiographic findings and patient characteristics. Clinical and radiological data were reviewed, and outcomes were assessed using the Raymond-Roy classification (RRC) and modified Rankin Scale (mRS). Follow-up radiological examinations were conducted at specific intervals. RESULTS: EVT was successful in all 54 cases. Immediate postprocedural angiograms showed favorable occlusion (RRC I or II) in 59.3% and aneurysm remnants (RRC III) in 40.7%. Procedure-related complications occurred in 7.4% of patients, including thromboembolism and ICA dissection, with no permanent neurological impairment. During a mean 18.2-month follow-up, no neurological deterioration or aneurysmal rupture occurred. Most patients showed stable/improved occlusion on follow-up imaging, with a 14% recurrence rate. Retreatment was required in 2% of cases. CONCLUSIONS: EVT appears feasible, safe, and effective for treating M1 hilltop aneurysms. It resulted in favorable occlusion and low recurrence/retreatment rates. Neck diameter and stent usage influenced immediate outcomes and recurrence. Larger studies with longer follow-ups are needed to validate these findings further.

Electrochemical and optical characterization of cobalt, copper and zinc phthalocyanine complexes.

New phthalocyanine (Pc) derivatives that include the alkyl group in ligand were synthesized based on three core metals such as zinc (Zn), copper (Cu), and cobalt (Co). Electrochemical behaviors and optical properties of the new phthalocyanine derivatives with ligand and different core metal were investigated by using cyclic voltammetry, UV-Visible (UV-Vis) spectroscopy and photoluminescence (PL) spectroscopy. In UV-Vis data, maximum values of 2H, Co, Cu, and Zn complexes were 708 nm and 677 nm, 686 nm, 684 nm, respectively.

Alleviating psoriatic skin inflammation through augmentation of Treg cells via CTLA-4 signaling peptide.

Psoriasis is a chronic inflammatory skin disease characterized by hyperplasia of keratinocytes and immune cell infiltration. The IL-17-producing T cells play a key role in psoriasis pathogenesis, while regulatory T (Treg) cells are diminished during psoriatic inflammation. Current psoriasis treatments largely focus on IL-17 and IL-23, however, few studies have explored therapeutic drugs targeting an increase of Treg cells to control immune homeostasis. In this study, we investigated the effects of a cytotoxic T lymphocyte antigen-4 (CTLA-4) signaling peptide (dNP2-ctCTLA-4) in Th17, Tc17, γδ T cells, Treg cells in vitro and a mouse model of psoriasis. Treatment with dNP2-ctCTLA-4 peptide showed a significant reduction of psoriatic skin inflammation with increased Treg cell proportion and reduced IL-17 production by T cells, indicating a potential role in modulating psoriatic skin disease. We compared dNP2-ctCTLA-4 with CTLA-4-Ig and found that only dNP2-ctCTLA-4 ameliorated the psoriasis progression, with increased Treg cells and inhibited IL-17 production from γδ T cells. In vitro experiments using a T cell-antigen presenting cell co-culture system demonstrated the distinct mechanisms of dNP2-ctCTLA-4 compared to CTLA-4-Ig in the induction of Treg cells. These findings highlight the therapeutic potential of dNP2-ctCTLA-4 peptide in psoriasis by augmenting Treg/Teff ratio, offering a new approach to modulating the disease.

Strategy for colorimetric and reversible recognition of strong acid in solution, solid, and dyed fabric conditions: Substitution of aminophenoxy groups to phthalocyanine.

A series of novel peripherally tetra- and octa-substituted copper phthalocyanines (CuPcs) bearing various aminophenoxy groups was designed and synthesized for detecting strong Brønsted acids. Octa-(diethyl-aminophenoxy)-substituted CuPc 5 exhibited excellent HCl detection capability with high sensitivity (limit of detection: 240 ppb), rapid (<2s), and selectivity for strong acids in versatile conditions including solution, solid, and dyed fabric. Furthermore, CuPc 5 noted reusability in recyclable tests with HCl and NH3, demonstrating its great potential for practical detection of HCl and ammonia gas leak under various environments. Based on systemic characterizations based on UV-Vis absorption spectra and NMR, we suggest that the proton of HCl associated with the N atom of CuPc 5, and the proton sensing abilities are directly related to the dissociation constants of the amine groups. The steric hindrance of alkyl chains and molar absorption coefficient of the CuPc species in THF solvent, as well as the H2O content of the solvent system, also affected the sensing performance. Due to less bulky nature of diethyl-amino groups having higher pKa and stronger basicity, CuPc 5 featured effective recognition of strong acids with pKa value less than -2.0 (Ka > 100). To the best of our knowledge, this is the first demonstration of pKa-sensitive colorimetric chemosensor using CuPc backbone, in particular for distinguishing strong Brønsted acids such as HCl.

Follow-up imaging of clipped intracranial aneurysms with 3-T MRI: comparison between 3D time-of-flight MR angiography and pointwise encoding time reduction with radial acquisition subtraction-based MR angiography.

OBJECTIVE: Metallic susceptibility artifact due to implanted clips is a major limitation of using 3D time-of-flight magnetic resonance angiography (TOF-MRA) for follow-up imaging of clipped aneurysms (CAs). The purpose of this study was to compare pointwise encoding time reduction with radial acquisition (PETRA) subtraction-based MRA with TOF-MRA in terms of imaging quality and visibility of clip-adjacent arteries for use in follow-up imaging of CAs. METHODS: Sixty-two patients with 73 CAs were included retrospectively in this comparative study. All patients underwent PETRA-MRA after TOF-MRA performed simultaneously with 3-T MRI between September 2019 and March 2020. Two neuroradiologists independently compared images obtained with both MRA modalities to evaluate overall image quality using a 4-point scale and visibility of the parent artery and branching vessels near the clips using a 3-point scale. Subgroup analysis was performed according to the number of clips (less-clipped [1-2 clips] vs more-clipped [≥ 3 clips] aneurysms). The ability to detect aneurysm recurrence was also assessed. RESULTS: Compared with TOF-MRA, PETRA-MRA showed acceptable image quality (score of 3.97 ± 0.18 for TOF-MRA vs 3.73 ± 0.53 for PETRA-MRA) and had greater visibility of the adjacent vessels near the CAs (score of 1.25 ± 0.59 for TOF-MRA vs 2.27 ± 0.75 for PETRA-MRA, p < 0.0001). PETRA-MRA had greater visibility of vessels adjacent to less-clipped aneurysms (score of 2.39 ± 0.75 for less-clipped aneurysms vs 2.09 ± 0.72 for more-clipped aneurysms, p = 0.014). Of 73 CAs, aneurysm recurrence in 4 cases was detected using PETRA-MRA. CONCLUSIONS: This study demonstrated that PETRA-MRA is superior to TOF-MRA for visualizing adjacent vessels near clips and can be an advantageous alternative to TOF-MRA for follow-up imaging of CAs.

Predictors of Ventriculostomy-Associated Infections: A Retrospective Study of 243 Patients.

OBJECTIVE: Risk factors of ventriculostomy-associated infection (VAI) reported in the literature are variable owing to heterogeneity of external ventricular drainage (EVD) procedures and management. This study aimed to assess the rate of VAI and its risk factors. METHODS: The medical records of patients >18 years old who received EVD catheterizations between January 2015 and December 2020 were retrospectively reviewed. RESULTS: Among 243 patients with 355 catheters, 23 VAIs were identified, yielding VIA rates of 9.5% per patient and 6.5% per catheter. VAI was associated with a longer total EVD duration (29.2 days vs. 15.8 days, P < 0.001), a longer procedural time (72 minutes vs. 41 minutes, P < 0.001), intraoperative ventriculostomy (39.1% vs. 9.1%, P < 0.001), craniotomy (87.0% vs. 60.9%, P = 0.014), and other systemic infections (30.4% vs. 8.2%, P = 0.004). On multivariate analysis, a longer total EVD duration (odds ratio 1.086, P < 0.001), intraoperative ventriculostomy (odds ratio 6.119, P = 0.001), and other systemic infections (odds ratio 4.620, P = 0.015) were associated with VAI. There was no statistical difference between the VAI rates of patients with and without prophylactic EVD exchanges at a mean 12.6 days (7.1% vs. 2.2%, P = 0.401). CONCLUSIONS: Intraoperative ventriculostomy was independently associated with VAI. Prophylactic EVD exchange at 12.6 days did not lower VAI rate.

Ankyloglossia correction: Z-plasty combined with genioglossus myotomy.

Ankyloglossia or tongue-tie is a disease in which the tongue has a mobility disorder because the lingual frenulum is short and tight, and as a result, the tongue tip is tied up. It may be asymptomatic or may cause various problems such as articulation disorder. Surgical treatment is required in many of the patients, and conventional methods release only the mucosal layer of the frenulum. However, conventional method alone is not as effective; therefore, the authors studied the addition of a partial myotomy of the genioglossus muscle along with mucosal layer release for treatment. The authors performed the surgery on 106 patients from 2005 to 2010, and during the surgery, the mucosal layer was released through Z-plasty after myotomy was performed on the contracted genioglossus muscle. During the follow-up, none of the patients showed signs and symptoms of tongue mobility impairment or articulation disorder caused by the partial myotomy of the genioglossus muscle, and a satisfactory outcome was obtained in achieving mobility of the tongue tip. Because tongue mobility disorder in ankyloglossia is accompanied by the contracture and shortening of the genioglossus muscle, an improved outcome is expected in the projection and mobility of the tongue tip from the combined application of conventional Z-plasty and genioglossus muscle release.

Facile Post Treatment of Ag Nanowire/Polymer Composites for Flexible Transparent Electrodes and Thin Film Heaters.

Typical polyol-based synthesis of silver nanowire employs insulating polymer as a surfactant for the silver nanowire growth, which limits direct contact between each nanowire and thus its optoelectronic properties. We herein demonstrate that a simple solvent treatment effectively removes the insulating polymer around Ag NWs, leading to significantly decreased sheet resistance (~12 Ω/sq) with an increased transmittance (81% @ T550), as compared to other post-treatments. We successfully demonstrate the transparent film heaters using the solvent-treated Ag NWs network, which rapidly exhibited 150 °C under a bias of 5 V. Flexible film heaters on plastic substrate is also demonstrated, suggesting a great potential of the solvent treatment process of Ag NWs for flexible transparent electrode and film heater applications.

Formation, Growth, or Rupture of De Novo Intracranial Aneurysms: Long-Term Follow-up Study of Subarachnoid Hemorrhage Survivors.

BACKGROUND: The survival rate of aneurysmal subarachnoid hemorrhage (aSAH) has gradually increased, leading to more clinical cases of de novo intracranial aneurysms (DNIAs). OBJECTIVE: To identify the characteristics of patients with DNIA growth or rupture. METHODS: We included 1601 patients with aSAH treated by clipping from January 1993 to May 2010. According to the inclusion and exclusion criteria, 233 patients had no DNIAs, and 63 patients had 77 DNIAs. We assessed the incidence rate of DNIAs and risk factors for DNIA formation. After dichotomizing the DNIA group into the heed (patients with DNIA rupture or growth) and stable groups (patients without DNIA growth), we assessed the risk factors for DNIA growth or rupture. RESULTS: The total follow-up period was 4427.9 patient-years. The incidence rate per patient-year was 1.42%. Age ≤50 yr, family history of aneurysm, and multiplicity at initial aSAH were significant risk factors for DNIA formation. Multivariate regression analysis revealed that female sex (odds ratio [OR], 5.566; 95% confidence interval [CI], 1.241-24.952), duration from initial aSAH to DNIA detection <120 mo (OR, 5.043; 95% CI, 1.362-18.668), multiplicity at initial aSAH (OR, 4.859; 95% CI, 1.207-19.563), and maximum DNIA diameter ≥4 mm (OR, 11.104; 95% CI, 2.337-52.772) were significant risk factors for DNIA growth or rupture. CONCLUSION: DNIAs had a higher incidence rate than expected. Taking into account the presented incidence rate and risk factors, long-term surveillance in aSAH survivors for more than a decade may be worth considering, at least on a case-by-case basis.

ZrSnO4: A Solution-Processed Robust Electron Transport Layer of Efficient Planar-Heterojunction Perovskite Solar Cells.

A robust electron transport layer (ETL) is an essential component in planar-heterojunction perovskite solar cells (PSCs). Herein, a sol-gel-driven ZrSnO4 thin film is synthesized and its optoelectronic properties are systematically investigated. The optimized processing conditions for sol-gel synthesis produce a ZrSnO4 thin film that exhibits high optical transmittance in the UV-Vis-NIR range, a suitable conduction band maximum, and good electrical conductivity, revealing its potential for application in the ETL of planar-heterojunction PSCs. Consequently, the ZrSnO4 ETL-based devices deliver promising power conversion efficiency (PCE) up to 19.05% from CH3NH3PbI3-based planar-heterojunction devices. Furthermore, the optimal ZrSnO4 ETL also contributes to decent long-term stability of the non-encapsulated device for 360 h in an ambient atmosphere (T~25 °C, RH~55%,), suggesting great potential of the sol-gel-driven ZrSnO4 thin film for a robust solution-processed ETL material in high-performance PSCs.

Delays in Intracerebral Hemorrhage Management Is Associated with Hematoma Expansion and Worse Outcomes: Changes in COVID-19 Era.

PURPOSE: The coronavirus disease 2019 (COVID-19) pandemic disrupted the emergency medical care system worldwide. We analyzed the changes in the management of intracerebral hemorrhage (ICH) and compared the pre-COVID-19 and COVID-19 eras. MATERIALS AND METHODS: From March to October of the COVID-19 era (2020), 83 consecutive patients with ICH were admitted to four comprehensive stroke centers. We retrospectively reviewed the data of patients and compared the treatment workflow metrics, treatment modalities, and clinical outcomes with the patients admitted during the same period of pre-COVID-19 era (2017-2019). RESULTS: Three hundred thirty-eight patients (83 in COVID-19 era and 255 in pre-COVID-19 era) were included in this study. Symptom onset/detection-to-door time [COVID-19; 56.0 min (34.0-106.0), pre-COVID-19; 40.0 min (27.0-98.0), p=0.016] and median door to-intensive treatment time differed between the two groups [COVID-19; 349.0 min (177.0-560.0), pre-COVID-19; 184.0 min (134.0-271.0), p<0.001]. Hematoma expansion was detected more significantly in the COVID-19 era (39.8% vs. 22.1%, p=0.002). At 3-month follow-up, clinical outcomes of patients were worse in the COVID-19 era (Good modified Rankin Scale; 33.7% in COVID19, 46.7% in pre-COVID-19, p=0.039). CONCLUSION: During the COVID-19 era, delays in management of ICH was associated with hematoma expansion and worse outcomes.

Washable Colorimetric Nanofiber Nonwoven for Ammonia Gas Detection.

The colorimetric sensor is a facile, cost-effective, and non-power-operated green energy material for gas detection. In this study, the colorimetric sensing property of a meta-aramid/dye 3 nanofiber sensor for ammonia (NH3) gas detection was investigated. This colorimetric sensor was prepared using various dye 3 concentrations via electrospinning. Morphological, thermal, structural, and mechanical analyses of the sensor were carried out by field-emission scanning electron microscopy, thermogravimetric analysis, Fourier-transform infrared spectroscopy, and a universal testing machine, respectively. A homemade computer color matching machine connected with a gas flow device characterized the response of the meta-aramid/dye 3 nanofiber colorimetric sensor to various exposure levels of NH3 gas. From the results, we confirmed that this colorimetric green energy sensor could detect ammonia gas in the concentration of 1-10 ppm with a sensing response time of 10 s at room temperature. After washing with laundry detergent for 30 min, the colorimetric sensors still exhibited sensing property and reversibility.

Colorimetric Dye-Loaded Nanofiber Yarn: Eye-Readable and Weavable Gas Sensing Platform.

The colorimetric gas sensor offers an opportunity for the simple and rapid detection of toxic gaseous substances based on visually discernible changes in the color of the sensing material. In particular, the accurate detection of trace amounts of certain biomarkers in a patient's breath provides substantial clues regarding specific diseases, for example, hydrogen sulfide (H2S) for halitosis and ammonia (NH3) for kidney disorder. However, conventional colorimetric sensors often lack the sensitivity, selectivity, detection limit, and mass-productivity, impeding their commercialization. Herein, we report an inexpensive route for the meter-scale synthesis of a colorimetric sensor based on a composite nanofiber yarn that is chemically functionalized with an ionic liquid as an effective H2S adsorbent and lead acetate as a colorimetric dye. As an eye-readable and weavable sensing platform, the single-strand yarn exhibits enhanced sensitivity supported by its high surface area and well-developed porosity to detect the breath biomarker (1 ppm of H2S). Alternatively, the yarn loaded with lead iodide dyes could reversibly detect NH3 gas molecules in the ppm-level, demonstrating the facile extensibility. Finally, we demonstrated that the freestanding yarns could be sewn into patterned textiles for the fabrication of a wearable toxic gas alarm system with a visual output.

Colorimetric Textile Sensor for the Simultaneous Detection of NH3 and HCl Gases.

For the immediate detection of strong gaseous alkalis and acids, colorimetric textile sensors based on halochromic dyes are highly valuable for monitoring gas leakages. To date, colorimetric textile sensors for dual-gas detection have usually been fabricated by electrospinning methods. Although nanofibrous sensors have excellent pH sensitivity, they are difficult to use commercially because of their low durability, low productivity, and high production costs. In this study, we introduce novel textile sensors with high pH sensitivity and durability via a facile and low-cost screen-printing method. To fabricate these textiles sensors, Dye 3 and RhYK dyes were both incorporated into a polyester fabric. The fabricated sensors exhibited high detection rates (<10 s) and distinctive color changes under alkaline or acidic conditions, even at low gas concentrations. Furthermore, the fabricated sensors showed an outstanding durability and reversibility after washing and drying and were confirmed to contain limited amounts of hazardous materials. Thus, our results show that the fabricated textile sensors could be used in safety apparel that changes its color in the presence of harmful gases.

A Highly Porous Nonwoven Thermoplastic Polyurethane/Polypropylene-Based Triboelectric Nanogenerator for Energy Harvesting by Human Walking.

: A highly porous nonwoven thermoplastic polyurethane (TPU)/Polypropylene (PP) triboelectric nanogenerator (N-TENG) was developed. To fabricate the triboelectric layers, the TPU nanofiber was directly electrospun onto the nonwoven PP at different basis weights (15, 30, and 50 g/m2). The surface morphologies and porosities of the nonwoven PP and TPU nanofiber mats were characterized by field-emission scanning electron microscopy and porosimetry. The triboelectric performance of the nonwoven TPU/PP based TENG was found to improve with an increase in the basis weight of nonwoven PP. The maximum output voltage and current of the TPU/PP N-TENG with 50% PP basis weight reached 110.18 ± 6.06 V and 7.28 ± 0.67 µA, respectively, due to high air volume of nonwoven without spacers. In order to demonstrate its practical application as a generator, a TPU/PP N-TENG-attached insole for footwear was fabricated. The N-TENG was used as a power source to turn on 57 light-emitting diodes through human-walking, without any charging system. Thus, owing to its excellent energy-conversion performance, simple fabrication process, and low cost, the breathable and wearable nonwoven fiber-based TENG is suitable for large-scale production, to be used in wearable devices.