Structurally Aligned Multifunctional Neural Probe (SAMP) Using Forest-Drawn CNT Sheet onto Thermally Drawn Polymer Fiber for Long-Term In Vivo Operation

Neural probe engineering is a dynamic field, driving innovation in neuroscience and addressing scientific and medical demands. Recent advancements involve integrating nanomaterials to improve performance, aiming for sustained in vivo functionality. However, challenges persist due to size, stiffness, complexity, and manufacturing intricacies. To address these issues, a neural interface utilizing freestanding CNT-sheets drawn from CNT-forests integrated onto thermally drawn functional polymer fibers is proposed. This approach yields a device with structural alignment, resulting in exceptional electrical, mechanical, and electrochemical properties while retaining biocompatibility for prolonged periods of implantation. This Structurally Aligned Multifunctional neural Probe (SAMP) employing forest-drawn CNT sheets demonstrates in vivo capabilities in neural recording, neurotransmitter detection, and brain/spinal cord circuit manipulation via optogenetics, maintaining functionality for over a year post-implantation. The straightforward fabrication method's versatility, coupled with the device's functional reliability, underscores the significance of this technique in the next-generation carbon-based implants. Moreover, the device's longevity and multifunctionality position it as a promising platform for long-term neuroscience research.

Nanomaterial-Based Artificial Vision Systems: From Bioinspired Electronic Eyes to In-Sensor Processing Devices

High-performance robotic vision empowers mobile and humanoid robots to detect and identify their surrounding objects efficiently, which enables them to cooperate with humans and assist human activities. For error-free execution of these robots' tasks, efficient imaging and data processing capabilities are essential, even under diverse and complex environments. However, conventional technologies fall short of meeting the high-standard requirements of robotic vision under such circumstances. Here, we discuss recent progress in artificial vision systems with high-performance imaging and data processing capabilities enabled by distinctive electrical, optical, and mechanical characteristics of nanomaterials surpassing the limitations of traditional silicon technologies. In particular, we focus on nanomaterial-based electronic eyes and in-sensor processing devices inspired by biological eyes and animal visual recognition systems, respectively. We provide perspectives on key nanomaterials, device components, and their functionalities, as well as explain the remaining challenges and future prospects of the artificial vision systems.

Implantable anti-biofouling biosupercapacitor with high energy performance

Biofluidic open-type supercapacitors offer significant advantages over batteries in implantable electronics. However, poor energy storage in bioelectrolytes and performance degradation owing to electrode biofouling remain challenges and hamper their implementation. In this study, we present a flexible polydopamine (PDA)-infiltrated carbon nanotube (CNT) yarn (PDA/CNT) supercapacitor with high performance in biofluids, encapsulated by a hydrogel-barrier circular knit that provides anti-biofouling protection. Infiltration of the biopolymer PDA provide a hydrophilic coating to obtain a hydrophobic CNT electrode under aqueous conditions and an energy density 250-fold higher than that of the pristine CNT in the biofluid. The PDA/CNT supercapacitor exhibited remarkable energy performance in biological fluids in terms of the maximum areal capacitance (503.91 mF cm-2), energy density (274 μWh/cm2), and power density (25.52 mW cm-2). Moreover, it demonstrated negligible capacitance loss after 10,000 repeated charge/discharge cycles and bending tests. To prevent biofouling, the PDA/CNT electrode was encapsulated in an agarose-coated circular knit that allows free movement of the electrolyte. Notably, implanting an encapsulated PDA/CNT supercapacitor into the abdominal cavity of rat resulted in stable in vivo energy storage performance without biofouling for 21 d, and the charged supercapacitor was used successfully to power a light-emitting diode in vivo.

Soft Bioelectronics for Neuroengineering: New Horizons in the Treatment of Brain Tumor and Epilepsy

Soft bioelectronic technologies for neuroengineering have shown remarkable progress, which include novel soft material technologies and device design strategies. Such technological advances that are initiated from fundamental brain science are applied to clinical neuroscience and provided meaningful promises for significant improvement in the diagnosis efficiency and therapeutic efficacy of various brain diseases recently. System-level integration strategies in consideration of specific disease circumstances can enhance treatment effects further. Here, recent advances in soft implantable bioelectronics for neuroengineering, focusing on materials and device designs optimized for the treatment of intracranial disease environments, are reviewed. Various types of soft bioelectronics for neuroengineering are categorized and exemplified first, and then details for the sensing and stimulating device components are explained. Next, application examples of soft implantable bioelectronics to clinical neuroscience, particularly focusing on the treatment of brain tumor and epilepsy are reviewed. Finally, an ideal system of soft intracranial bioelectronics such as closed-loop-type fully-integrated systems is presented, and the remaining challenges for their clinical translation are discussed.

Novel Deposition Method of Crosslinked Polyethylene Thin Film for Low-Refractive-Index Mid-Infrared Optical Coatings

Mid-infrared optics require optical coatings composed of high- and low-refractive-index dielectric layers for the design of optical mirrors, filters, and anti-reflection coatings. However, there are not many technologies for depositing a material with a refractive index of less than 2 and a low loss in the mid-infrared region. Here, we present a unique deposition method of crosslinked polyethylene thin film for mid-IR optical filter design. Polyethylene has a refractive index of 1.52 in the mid-infrared region and a small number of absorption peaks, so it is useful for making optical filters in the mid-infrared region. Only 1 keV of energy is required to crosslink the entire film by irradiating an electron beam while depositing polyethylene. In addition, crosslinked polyethylene thin film has high mechanical strength, so there is no cracking or peeling when used with germanium. This allows for the use of crosslinked polyethylene as a low refractive index for mid-infrared optical coating.

Chiral Diketopyrrolopyrrole-Based Conjugated Polymers with Intramolecular Rotation-Isomeric Conformation Asymmetry for Near-Infrared Circularly Polarized Light-Sensing Organic Phototransistors

Recent advances in chiral nanomaterials interacting with circularly polarized (CP) light open new expectations for optoelectronics in various research fields such as quantum- and biology-related technology. To fully utilize the great potential of chiral optoelectronic devices, the development of chiral optoelectronic devices that function in the near-infrared (NIR) region is required. Herein, we demonstrate a NIR-absorbing, chiroptical, low-band-gap polymer semiconductor for high-performance NIR CP light phototransistors. A newly synthesized diketopyrrolopyrrole-based donor-acceptor-type chiral π-conjugated polymer with an asymmetric alkyl side chain exhibits strong chiroptical activity in a wavelength range of 700-1000 nm. We found that the attachment of an enantiomerically pure stereogenic alkyl substituent to the π-conjugated chromophore backbone led to strong chiroptical activity through symmetry breaking of the π-conjugation of the backbone in a molecular rotational motion while maintaining the coplanar backbone conformation for efficient charge transport. The NIR CP light-sensing phototransistors based on a chiral π-conjugated polymer photoactive single channel layer exhibit a high photoresponsivity of 26 A W-1 under NIR CP light irradiation at 920 nm, leading to excellent NIR CP light distinguishability. This study will provide a rationale and strategy for designing chiral π-conjugated polymers for high-performance NIR chiral optoelectronics.

Transition of Carbon Nanotube Sheets from Hydrophobicity to Hydrophilicity by Facile Electrochemical Wetting

The present study delves into the transformative effects of electrochemical oxidation on the hydrophobic-to-hydrophilic transition of carbon nanotube (CNT) sheets. The paper elucidates the inherent advantages of CNT sheets, such as high electrical conductivity and mechanical strength, and contrasts them with the limitations posed by their hydrophobic nature. A comprehensive investigation is conducted to demonstrate the efficacy of electrochemical oxidation treatment in modifying the surface properties of CNT sheets, thereby making them hydrophilic. The study reveals that the treatment not only is cost-effective and time-efficient compared to traditional plasma treatment methods but also results in a significant decrease in water contact angle. Mechanistic insights into the hydrophilic transition are provided, emphasizing the role of oxygen-containing functional groups introduced during the electrochemical oxidation process.

Ultrathin Self-Powered Heavy-Metal-Free Cu-In-Se Quantum Dot Photodetectors for Wearable Health Monitoring

Mechanically deformable photodetectors (PDs) are key device components for wearable health monitoring systems based on photoplethysmography (PPG). Achieving high detectivity, fast response time, and an ultrathin form factor in the PD is highly needed for next-generation wearable PPG systems. Self-powered operation without a bulky power-supply unit is also beneficial for point-of-care application. Here, we propose ultrathin self-powered PDs using heavy-metal-free Cu-In-Se quantum dots (QDs), which enable high-performance wearable PPG systems. Although the light-absorbing QD layer is extremely thin (∼40 nm), the developed PD exhibits excellent performance (specific detectivity: 2.10 × 1012 Jones, linear dynamic range: 102 dB, and spectral range: 250-1050 nm at zero bias), which is comparable to that of conventional rigid QD-PDs employing thick Pb-chalcogenide QD layers. This is attributed to material and device strategies─materials that include Cu-In-Se QDs, a MoS2-nanosheet-blended poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) hole transport layer, a ZnO nanoparticle electron transport layer, Ag and ITO electrodes, and an ultrathin form factor (∼120 nm except the electrodes) that enable excellent mechanical deformability. These allow the successful application of QD-PDs to a wearable system for real-time PPG monitoring, expanding their potential in the field of mobile bioelectronics.

Electrochemically Oxidized Carbon Nanotube Sheets for High-Performance and Flexible-Film Supercapacitors

The development of flexible, high-performance supercapacitors has been a focal point in energy storage research. While carbon nanotube (CNT) sheets offer promising mechanical and electrical properties, their low electrical double-layer capacitance significantly limits their practicability. Herein, we introduce a novel approach to address this challenge via the electrochemical oxidation treatment of CNT sheets stacked on a polyethylene terephthalate substrate. This introduces oxygen-containing functional groups onto the CNT surface, thereby dramatically enhancing the pseudocapacitive effect and improving ion adsorption. Consequently, using the material in a two-electrode system increased the capacitance by 54 times compared to pristine CNT. The results of electrochemical performance characterization, including cyclic voltammograms, galvanostatic charge/discharge curves, and capacitance retention testing data, confirm the efficacy of the electrochemical oxidation approach. Furthermore, the mechanical flexibility of the electrochemically wetted CNT sheets was validated through resistance and discharge retention testing under repetitive bending (98% capacitance retention after 1000 bending cycles). The results demonstrate that electrochemically wetted CNT sheets retain their intrinsic mechanical and electrical properties while significantly enhancing the electrochemical performance (0.59 mF/cm2 or 97.8 F/g). This work represents a significant advancement in the development of flexible, high-performance supercapacitors with potential applicability to wearable electronics, flexible displays, and next-generation energy storage solutions.

Determining the Dosimetric Accuracy of Deep Learning-Based Fully Automated Registration-Segmentation Approach for Thoracic Cancer Organs-at-Risk Contouring

PURPOSE/OBJECTIVE(S)

For adaptive radiation therapy (ART), the contours on the planning CT (pCT) are frequently propagated to cone-beam CT (CBCT) via deformable image registration and manually edited, which is observer-dependent and time-consuming. To automate this process, we created a fully automated workflow by combining a deep learning (DL)-based pCT segmentation model with a CT-to-CBCT registration-segmentation DL model. The purpose of our research is to determine how using the proposed workflow's automatically generated contours affects thoracic organs-at-risk sparing (OAR).

MATERIALS/METHODS

Seven patients with locally advanced non-small cell lung cancer who underwent treatment with intensity modulated radiation therapy were included in this study. Each patient's pCT was segmented using a published DL model that has been used for generating thoracic OAR segmentation and radiotherapy planning in the clinic since July of 2020. Next, pCT was deformably registered using a published recurrent deep registration-segmentation method. Whereas the original method's segmentation sub-network was only trained to segment esophagus, the registration sub-network was used to propagate contours for heart, esophagus, and the proximal bronchial tree (PBT). Geometric segmentation accuracy using the Dice Similarity Coefficient (DSC) and the 95th percentile Hausdorff Distance (HD) and dose metrics including the mean esophageal dose (MED) and D90% of the heart (D90) were computed from the total accumulated dose for the first two weeks of treatment.

RESULTS

The esophagus had a high DSC and a low HD (0.93 and 2.85mm) and conversely, the heart had lower accuracy (DSC = 0.85, HD = 22.06mm). PBT showed relatively high performance as well, with DSC of 0.91 and HD of 2.28mm, owing to its proximity to the esophagus. The accumulated MED for manual contour was slightly lower than AI-contours (11.34 vs 11.83 Gy), suggesting reliability of the proposed workflow. The reverse is seen for the D90 of the heart (manual = 1.74 and AI-contour = 1.56 Gy), likely due to the heart not being included in the original DL framework.

CONCLUSION

This study reported preliminary results on the feasibility of using a fully automated and patient-specific workflow for CBCT auto-segmentation in ART, confirming its role as a geometrically and dosimetrically accurate solution for thoracic OARs. However, because it is currently limited to the esophagus, we believe that re-training the algorithm will increase confidence in other OARs such as the heart and lungs.

Clinical Feasibility of Deep Learning-Based CT during Treatment CBCT Tumor Registration-Segmentation in Thoracic Radiotherapy (RT)

PURPOSE/OBJECTIVE(S)

Accurate tumor segmentation on weekly cone-beam computed tomography (CBCT) images is critical for image-guided and adaptive radiation therapy (ART). In thoracic RT, low image contrast, imaging artifact, and geometry and image modality differences from the planning CT (pCT) typically limits accurate tumor segmentation and registration. Here, we explored the clinical feasibility of using 3D recurrent registration-segmentation deep learning (DL) that combines patient-specific anatomic and shape context from higher contrast pCT and planning contours (PACs) for tumor segmentation on during treatment CBCTs.

MATERIALS/METHODS

We included the pCT and CBCTs from six patients with locally advanced non-small cell lung cancer (LA-NSCLC) who had underwent RT. Cases were selected with a primary GTV contoured and labeled separately from the nodal GTV. Using rigidly aligned pCT and CBCT as inputs, DL auto-segmented the GTV on week 1 and 6 CBCTs, and these auto-segmented contours were manually inspected by a radiation oncologist that edited the GTV according to clinical standard quality. The Dice similarity coefficient (DSC), Hausdorff distance (HD95), mean surface distance (MSD), surface DSC (sDSC) and added path length (APL) were used to quantitively compare the DL and the edited GTV.

RESULTS

The primary GTV was in the right lung in five cases, and left lung in one case. Manual adjustments were typically made at the interface of GTV and lung parenchyma with partial inclusion of adjacent vessels. Hypodensities within the GTV were sometimes not segmented in all axial slices resulting in discontinuous components. The quantitative comparison between the edited and DL-generated GTV is shown in Table 1. For week 1, the average DSC and HD95 were 0.87 and 6.94 mm, respectively. The performance for week 6 was slightly lower than week 1, with a DSC of 0.85 and HD95 of 7.22 mm.

CONCLUSION

The agreement with the generated DL GTV and the edited GTV was high in week 1 and decreased somewhat later during the treatment course possibly due to a higher impact of geometric changes in tumor and adjacent structures. The proposed DL algorithm showed reasonable performance throughout the treatment, supporting its potential for use into clinical routine for LA-NSCLC.

A Review of Yarn-Based One-Dimensional Supercapacitors

Energy storage in a one-dimensional format is increasingly vital for the functionality of wearable technologies and is garnering attention from various sectors, such as smart apparel, the Internet of Things, e-vehicles, and robotics. Yarn-based supercapacitors are a particularly compelling solution for wearable energy reserves owing to their high power densities and adaptability to the human form. Furthermore, these supercapacitors can be seamlessly integrated into textile fabrics for practical utility across various types of clothing. The present review highlights the most recent innovations and research directions related to yarn-based supercapacitors. Initially, we explore different types of electrodes and active materials, ranging from carbon-based nanomaterials to metal oxides and conductive polymers, that are being used to optimize electrochemical capacitance. Subsequently, we survey different methodologies for loading these active materials onto yarn electrodes and summarize innovations in stretchable yarn designs, such as coiling and buckling. Finally, we outline a few pressing research challenges and future research directions in this field.

Chiroptical Synaptic Heterojunction Phototransistors Based on Self-Assembled Nanohelix of π-Conjugated Molecules for Direct Noise-Reduced Detection of Circularly Polarized Light

High-performance chiroptical synaptic phototransistors are successfully demonstrated using heterojunctions composed of a self-assembled nanohelix of a π-conjugated molecule and a metal oxide semiconductor. To impart strong chiroptical activity to the device, a diketopyrrolopyrrole-based π-conjugated molecule decorated with chiral glutamic acid is newly synthesized; this molecule is capable of supramolecular self-assembly through noncovalent intermolecular interactions. In particular, nanohelix formed by intertwinded fibers with strong and stable chiroptical activity in a solid-film state are obtained through hydrogen-bonding-driven, gelation-assisted self-assembly. Phototransistors based on interfacial charge transfer at the heterojunction from the chiroptical nanohelix to the metal oxide semiconductor show excellent chiroptical detection with a high photocurrent dissymmetry factor of 1.97 and a high photoresponsivity of 218 A W-1 . The chiroptical phototransistor demonstrates photonic synapse-like, time-dependent photocurrent generation, along with persistent photoconductivity, which is attributed to the interfacial charge trapping. Through the advantage of synaptic functionality, a trained convolutional neural network successfully recognizes noise-reduced circularly polarized images of handwritten alphabetic characters with better than 89.7% accuracy.

Hierarchically Plied Mechano-Electrochemical Energy Harvesting Using a Scalable Kinematic Sensing Textile Woven from a Graphene-Coated Commercial Cotton Yarn

Wearable sensing systems are suitable for monitoring human motion. To realize a cost-effective and self-powered strain-sensing fiber, we developed a mechano-electrochemical harvesting yarn and textile using hierarchically arranged plied yarns composed of meter-long graphene-coated cotton yarns. Such a fiber relies on the principle of electrochemical capacity change to convert mechanical energy to electric energy. Further, this harvester can be used as a self-powered strain sensor because its output depends on mechanical stimuli. Additionally, the yarn can be woven into a kinematic sensing textile that measures the strength and direction of the applied force. The textile-type harvester can successfully detect various human movements such as pressing, bending, and stretching. The proposed sensing fiber will pave the way for the development of advanced wearable systems for ubiquitous healthcare in the future.

Influence of Body Posture on Internal Organ Dosimetry: Radiocesium Exposure Modeling Using Novel Posture-dependent Mesh Computational Phantoms

ABSTRACT

Current practice in reference internal dosimetry assumes a fixed upright standing posture is maintained throughout the dose-integration period. Recently, the mesh-type ICRP adult reference computational phantoms were transformed into different body postures (e.g., sitting, squatting) for use in occupational dose reconstruction applications. Here, for the first time, we apply this phantom series to the study of organ dose estimates following radionuclide intake. We consider the specific cases of 137 Cs and 134 Cs ingestion (accidental/occupational intake) with attention to variability in absorbed dose as a function of posture. The ICRP Publication 137 systemic biokinetic model for soluble cesium ingestion was used to compute organ-level time-integrated activity coefficients for reference adults, over a 50-y dose-integration period, for 134 Cs and 137 Cs (and its radioactive progeny 137m Ba). Mean posture time-allocations (h d -1 for standing, sitting, and lying) were taken from published survey data. In accord with modern dosimetry formalisms (e.g., MIRD, ICRP), a posture weighting factor was introduced that accounts for the fraction of time spent within each independent posture. Absorbed dose coefficients were computed using PHITS Monte Carlo simulations. ICRP 103 tissue weighting factors were applied along with the posture weighting factors to obtain committed effective dose per unit intake (Sv Bq -1 ). For 137 Cs ingestion, most organ absorbed dose coefficients were negligibly to marginally higher (< ~3%) for sitting or crouched (lying fetal/semi-fetal) postures maintained over the dose commitment period, relative to the upright standing posture. The committed effective dose coefficients were 1.3 × 10 -8 Sv Bq -1 137 Cs for standing, sitting, or crouched postures; thus, the posture-weighted committed effective dose was not significantly different than the committed effective dose for a maintained upright standing posture. For 134 Cs ingestion, most organ absorbed dose coefficients for the sitting and crouched postures were significantly larger than the standing posture, but the differences were still considered minor (< ~8% for most organs). The committed effective dose coefficients were 1.2 × 10 -8 Sv Bq -1 134 Cs for the standing posture and 1.3 × 10 -8 Sv Bq -1 134 Cs for the sitting or crouched posture. The posture-weighted committed effective dose was 1.3 × 10 -8 Sv Bq -1 134 Cs. Body posture has minor influence on organ-level absorbed dose coefficients and committed effective dose for ingestion of soluble 137 Cs or 134 Cs.

Graphene/III-V Quantum Dot Mixed-Dimensional Heterostructure for Enhanced Radiative Recombinations via Hole Carrier Transfer

Fabrication of high quantum efficiency nanoscale device is challenging due to increased carrier loss at surface. Low dimensional materials such 0D quantum dots and 2D materials have been widely studied to mitigate the loss. Here, we demonstrate a strong photoluminescence enhancement from graphene/III-V quantum dot mixed-dimensional heterostructures. The distance between graphene and quantum dots in the 2D/0D hybrid structure determines the degree of radiative carrier recombination enhancement from 80% to 800% compared to the quantum dot only structure. Time-resolved photoluminescence decay also shows increased carrier lifetimes when the distance decreases from 50 to 10 nm. We propose that the optical enhancement is due to energy band bending and hole carrier transfer, which repair the imbalance of electron and hole carrier densities in quantum dots. This 2D graphene/0D quantum dot heterostructure shows promise for high performance nanoscale optoelectronic devices.

Fibriform Organic Electrochemical Diodes with Rectifying, Complementary Logic and Transient Voltage Suppression Functions for Wearable E-Textile Embedded Circuits

In this study, a fibriform electrochemical diode capable of performing rectifying, complementary logic and device protection functions for future e-textile circuit systems is fabricated. The diode was fabricated using a simple twisted assembly of metal/polymer semiconductor/ion gel coaxial microfibers and conducting microfiber electrodes. The fibriform diode exhibited a prominent asymmetrical current flow with a rectification ratio of over 10², and its performance was retained after repeated bending deformations and washings. Fundamental studies on the electrochemical interactions of polymer semiconductors with ions reveal that the Faradaic current generated in polymer semiconductors by electrochemical reactions results in an abrupt current increase under a forward bias, in which the threshold voltages of the device are determined by the oxidation or reduction potential of the polymer semiconductor. Textile-embedded full-wave rectifiers and logic gate circuits were implemented by simply integrating the fibriform diodes, exhibiting AC-to-DC signal conversion and logic operation functions, respectively. It was also confirmed that the proposed fibriform diode can suppress transient voltages and thus protect a low-voltage operational wearable e-textile circuit.

Enhanced Hydro-Actuation and Capacitance of Electrochemically Inner-Bundle-Activated Carbon Nanotube Yarns

Recently, several attempts have been made to activate or functionalize macroscopic carbon nanotube (CNT) yarns to enhance their innate abilities. However, a more homogeneous and holistic activation approach that reflects the individual nanotubes constituting the yarns is crucial. Herein, a facile strategy is reported to maximize the intrinsic properties of CNTs assembled in yarns through an electrochemical inner-bundle activation (EIBA) process. The as-prepared neat CNT yarns are two-end tethered and subjected to an electrochemical voltage (vs Ag/AgCl) in aqueous electrolyte systems. Massive electrolyte infiltration during the EIBA causes swelling of the CNT interlayers owing to the tethering and subsequent yarn shrinkage after drying, suggesting activation of the entire yarn. The EIBA-treated CNT yarns functionalized with oxygen-containing groups exhibit enhanced wettability without significant loss of their physical properties. The EIBA effect of the CNTs is experimentally demonstrated by hydration-driven torsional actuation (∼986 revolutions/m) and a drastic capacitance improvement (approximately 25-fold).

The value of performing cerebrovascular CT angiography in major trauma patients: a 5-year retrospective review

AIM

To assess whether routine cerebrovascular imaging is required in all major trauma (MT) patients.

MATERIALS AND METHODS

All MT patients with cerebrovascular imaging between January 2015 and December 2020 were included in the study. Data were collated regarding the type of indication for computed tomography (CT) angiography imaging, time interval from the initial trauma, relevant trauma diagnoses on initial trauma imaging, and CT angiography. Findings, such as aneurysms, vascular malformations, luminal thrombus, venous sinus thrombosis, or vascular injury, were collated. Subsequent treatment with anti-coagulants/anti-platelets or surgical/radiological intervention was noted. Follow-up imaging was assessed for residual injury or complications.

RESULTS

Two hundred and fifty of the 6,251 MT patients underwent dedicated cerebrovascular imaging and were included in the study. Of these 41 (16.4%) had cervical artery or venous sinus injury. Further positive vascular findings were identified in 25/250 patients who presented with an incidental stroke or a vascular abnormality and were mislabelled as MT patients at presentation. One patient with a carotid injury subsequently died following a large infarction. Another patient with vertebral artery injury suffered a non-lethal stroke. No patients underwent surgery or intervention.

CONCLUSION

The present study showed that the overall incidence of detected blunt cerebrovascular injuries was very low (0.6%) and even lower for symptomatic vascular injury (0.03%). Routine cerebrovascular imaging is not recommended in all MT trauma patients, but instead, a continued case-by-case basis should be considered.

Highly Elastically Deformable Coiled CNT/Polymer Fibers for Wearable Strain Sensors and Stretchable Supercapacitors

Stretchable yarn/fiber electronics with conductive features are optimal components for different wearable devices. This paper presents the construction of coil structure-based carbon nanotube (CNT)/polymer fibers with adjustable piezoresistivity. The composite unit fiber is prepared by wrapping a conductive carbon CNT sheath onto an elastic spandex core. Owing to the helical coil structure, the resultant CNT/polymer composite fibers are highly stretchable (up to approximately 300%) without a noticeable electrical breakdown. More specifically, based on the difference in the coil index (which is the ratio of the coil diameter to the diameter of the fiber within the coil) according to the polymeric core fiber (spandex or nylon), the composite fiber can be used for two different applications (i.e., as strain sensors or supercapacitors), which are presented in this paper. The coiled CNT/spandex composite fiber sensor responds sensitively to tensile strain. The coiled CNT/nylon composite fiber can be employed as an elastic supercapacitor with excellent capacitance retention at 300% strain.

Nanomaterial-Based Synaptic Optoelectronic Devices for In-Sensor Preprocessing of Image Data

With the advance in information technologies involving machine vision applications, the demand for energy- and time-efficient acquisition, transfer, and processing of a large amount of image data has rapidly increased. However, current architectures of the machine vision system have inherent limitations in terms of power consumption and data latency owing to the physical isolation of image sensors and processors. Meanwhile, synaptic optoelectronic devices that exhibit photoresponse similar to the behaviors of the human synapse enable in-sensor preprocessing, which makes the front-end part of the image recognition process more efficient. Herein, we review recent progress in the development of synaptic optoelectronic devices using functional nanomaterials and their unique interfacial characteristics. First, we provide an overview of representative functional nanomaterials and device configurations for the synaptic optoelectronic devices. Then, we discuss the underlying physics of each nanomaterial in the synaptic optoelectronic device and explain related device characteristics that allow for the in-sensor preprocessing. We also discuss advantages achieved by the application of the synaptic optoelectronic devices to image preprocessing, such as contrast enhancement and image filtering. Finally, we conclude this review and present a short prospect.

PdO-Nanoparticle-Embedded Carbon Nanotube Yarns for Wearable Hydrogen Gas Sensing Platforms with Fast and Sensitive Responses

Hydrogen (H₂) gas has recently become a crucial energy source and an imperative energy vector, emerging as a powerful next-generation solution for fuel cells and biomedical, transportation, and household applications. With increasing interest in H₂, safety concerns regarding personal injuries from its flammability and explosion at high concentrations (>4%) have inspired the development of wearable pre-emptive gas monitoring platforms that can operate on curved and jointed parts of the human body. In this study, a yarn-type hydrogen gas sensing platform (HGSP) was developed by biscrolling of palladium oxide nanoparticles (PdO NPs) and spinnable carbon nanotube (CNT) buckypapers. Because of the high loading of H₂-active PdO NPs (up to 97.7 wt %), when exposed to a flammable H₂ concentration (4 vol %), the biscrolled HGSP yarn exhibits a short response time of 2 s, with a high sensitivity of 1198% (defined as ΔG/G₀ × 100%). Interestingly, during the reduction of PdO to Pd by H₂ gas, the HGSP yarn experienced a decrease in diameter and corresponding volume contraction. These excellent sensing performances suggest that the fabricated HGSP yarn could be applied to a wearable gas monitoring platform for real-time detection of H₂ gas leakage even over the bends of joints.

Wearable and Washable MnO2-Zn Battery Packaged by Vacuum Sealing

Batteries are used in all types of electronic devices from conventional to advanced devices. Currently, batteries are evolving in the direction of extremely personalized yarn- or textile-structured textronic systems. However, the absence of a protective layer on such batteries is a critical limitation to their practical use. In this study, we developed a wearable and washable MnO₂-Zn textile battery that maintains its electrochemical capacity under various external environmental conditions through a vacuum-sealed packaging. The packaged textile battery was fabricated by vacuuming a polymer envelope containing the battery, followed by heat sealing with a vacuum packaging machine. The interior and exterior regions of the textile battery are completely separated by the packaging sheath to preclude leakage and intrusion of substances. The resulting packaged textile battery exhibits stable capacity retention performance under varying temperature and humidity; mechanical deformations due to bending, twisting, rubbing, and pressing; and several mechanical, chemical, and their combined washing cycles. On the basis of these demonstrations, we expect that our vacuum-packaged textile battery will offer new possibilities for practical and convenient use of textronics.

High-Performance Biscrolled Ni-Fe Yarn Battery with Outer Buffer Layer

The increasing demand for portable and wearable electronics has promoted the development of safe and flexible yarn-based batteries with outstanding electrochemical properties. However, achieving superior energy storage performance with a high active material (AM) load and long cycle life with this device format remains a challenge. In this study, a stable and rechargeable high-performance aqueous Ni-Fe yarn battery was constructed via biscrolling to embed AMs within helical carbon nanotube (CNT) yarn corridors. Owing to the high load of charge storage nanoparticles (NPs; above 97 wt%) and the outer neat CNT layer, the buffered biscrolled Ni-Fe yarn battery demonstrates excellent linear capacity (0.053 mAh/cm) and cycling stability (60.1% retention after 300 charge/discharge cycles) in an aqueous electrolyte. Moreover, our flexible yarn battery exhibits maximum energy/power densities of 422 mWh/cm³ and 7535 mW/cm³ based on the total volume of the cathode and anode, respectively, which exceed those reported for many flexible Ni-Fe batteries. Thus, biscrolled Ni-Fe yarn batteries are promising candidates for next-generation conformal energy solutions.

Integrated Mechano-Electrochemical Harvesting Fiber and Thermally Responsive Artificial Muscle for Self-Powered Temperature-Strain Dual-Parameter Sensor

Significant progress in healthcare fields around the world has inspired us to develop a wearable strain−temperature sensor that can monitor biomedical signals in daily life. This novel self-powered temperature−strain dual-parameter sensor comprises a mechano-electrochemical harvester (MEH) and a thermally responsive artificial muscle (TAM). The MEHTAM system generates electricity from strain and thermal fluctuations. In addition, the sensor is comfortable to wear, owing to its stretchability (>100%), softness (<3 MPa), and one-dimensional fibers (diameter 230 μm). The MEH induces a change in the electrochemical capacitance, resulting in an electrical signal under applied strain (34 μA/m) and stress (20 μA/(m·MPa)). The TAM can be used as a mechanical temperature sensor, because the tensile stroke responds linearly to changes in temperature. As the harvester and artificial muscle are combined, the MEHTAM system generates electricity, owing to external and internal mechanical stimuli caused by muscle contractions as a response to temperature changes. The MEHTAM system that we have developed—a self-powered, strain−temperature dual-parameter sensor that is soft, stretchable, and fiber-shaped—is an interesting candidate for the production of comfortable, wearable, dual-parameter sensors.

Elastomeric Core/Conductive Sheath Fibers for Tensile and Torsional Strain Sensors

Motion sensing, aimed at detecting and monitoring mechanical deformation, has received significant attention in various industrial and research fields. In particular, fiber-structured mechanical strain sensors with carbon-based materials have emerged as promising alternatives for wearable applications owing to their wearability and adaptability to the human body. Various materials, structures, sensing mechanisms, and fabrication methods have been used to fabricate high-performance fiber strain sensors. Nevertheless, developing multi-modal strain sensors that can monitor multiple deformations remains to be accomplished. This study established core/sheath fiber multi-modal strain sensors using polymer and carbon nanotubes (CNTs). Specifically, a flexible and conductive CNT sheet was wrapped onto the elastomeric core fiber at a certain angle. This wrapping angle allowed the CNTs to mechanically deform under tensile and torsional deformations without fatal structural damage. The CNTs could sense both tensile and torsional strains through reversible structural changes during deformations. The fiber strain sensor exhibited an increase of 124.9% and 9.6% in the resistance during tensile and torsional deformations of 100% and 1250 rad/m, respectively.

Microbuckled Mechano-electrochemical Harvesting Fiber for Self-Powered Organ Motion Sensors

Mechanical harvesters have attracted tremendous attention as self-powered strain sensors; previous harvesters required high stress to stretch the fiber because of their high Young's modulus and low elasticity. We report on a mechano-electrochemical harvesting (MECH) fiber based on the new buckle structure, which has a low Young's modulus (2 MPa) with high elasticity (up to 100%) in a similar physiological fluid. MECH converts mechanical energy into electrical energy by changing the capacitance due to changing the surface area caused by the microbuckle on the surface. The damage to the cells can be minimized by their softness; the fiber was stitched on the tissue of the pig stomach while maintaining the performance like a suture fiber. Additionally, the fiber successfully operated in an organ-similar system, which is composed of the stomach or bladder of a pig. The fiber has a high potential to be applied in wearable energy sources and self-powered strain sensors.

Chemo-Mechanical Energy Harvesters with Enhanced Intrinsic Electrochemical Capacitance in Carbon Nanotube Yarns

Predicting and preventing disasters in difficult-to-access environments, such as oceans, requires self-powered monitoring devices. Since the need to periodically charge and replace batteries is an economic and environmental concern, energy harvesting from external stimuli to supply electricity to batteries is increasingly being considered. Especially, in aqueous environments including electrolytes, coiled carbon nanotube (CNT) yarn harvesters have been reported as an emerging approach for converting mechanical energy into electrical energy driven by large and reversible capacitance changes under stretching and releasing. To realize enhanced harvesting performance, experimental and computational approaches to optimize structural homogeneity and electrochemical accessible area in CNT yarns to maximize intrinsic electrochemical capacitance (IEC) and stretch-induced changes are presented here. Enhanced IEC further enables to decrease matching impedance for more energy efficient circuits with harvesters. In an ocean-like environment with a frequency from 0.1 to 1 Hz, the proposed harvester demonstrates the highest volumetric power (1.6-10.45 mW cm^-3 ) of all mechanical harvesters reported in the literature to the knowledge of the authors. Additionally, a high electrical peak power of 540 W kg^-1 and energy conversion efficiency of 2.15% are obtained from torsional and tensile mechanical energy.

Integration of synaptic phototransistors and quantum dot light-emitting diodes for visualization and recognition of UV patterns

Synaptic photodetectors exhibit photon-triggered synaptic plasticity, which thus can improve the image recognition rate by enhancing the image contrast. However, still, the visualization and recognition of invisible ultraviolet (UV) patterns are challenging, owing to intense background noise. Here, inspired by all-or-none potentiation of synapse, we develop an integrated device of synaptic phototransistors (SPTrs) and quantum dot light-emitting diodes (QLEDs), facilitating noise reduction and visualization of UV patterns through on-device preprocessing. The SPTrs convert noisy UV inputs into a weighted photocurrent, which is applied to the QLEDs as a voltage input through an external current-voltage-converting circuit. The threshold switching characteristics of the QLEDs result in amplified current and visible illumination by the suprathreshold input voltage or nearly zero current and no visible illumination by the input voltage below the threshold. The preprocessing of image data with the SPTr-QLED can amplify the image contrast, which is helpful for high-accuracy image recognition.

Mechanical Testing of Artificial Vessels and Tissues for Photoplethysmography Phantoms

Various studies have looked at the efficiency of artificial vessel and tissue networks in the study of photoplethysmography (PPG) in an effort to better understand the origin of various morphological features present in the signal. Whilst there are all reasonable attempts made to replicate geometrical features such as vessel depth, vessel wall thickness and diameter etc., not many studies have attempted to replicate the mechanical properties such as vessel elasticity and tissue compressibility. This study reports two methods for tissue mechanical testing for the analysis of vessel elasticity and tissue compressibility. A two-part polydimethylsiloxane (PDMS) was used as a base material for both tissue and vessel construction, and the properties altered by changing the curing component ratio. Tissue compression properties were investigated using an industrially calibrated materials testing device using the protocol from the ASTM 0575-91 testing method. Vessel elasticity was investigated using a custom method and apparatus to report vessel diameter and length change simultaneously. Tissue compressive properties proved reasonably easy to replicate through catalyst alteration, however the vessel elasticity properties were found to be higher than expected at all reasonable catalyst ratios. The property of hyper-elasticity was observed in the artificial vessels though, leading to the conclusion that alternative material recipes or construction methods may be needed to correctly replicate the expected mechanical characteristics. Clinical Relevance- The latest generation of health monitoring devices, especially those that are wearable and used widely by individuals wishing to monitor their health daily are becoming smarter and more sophisticated in their functionality. The majority of such devices use photoplethysmography (PPG) as their primary monitoring technique. Being able to replicate the PPG in a phantom allows the continued study and development of devices, and to improve their functionality without the continued need for extensive user-testing.

Stretchy Electrochemical Harvesters for Binarized Self-Powered Strain Gauge-Based Static Motion Sensors

The human monitoring system has motivated the search for new technology, leading to the development of a self-powered strain sensor. We report on the stretchable and soft stretchy electrochemical harvester (SECH) bilayer for a binarized self-powered strain gauge in dynamic and static motion. The active surface area participating in the electrochemical reaction was enhanced after stretching the SECH in the electrolyte, leading to an increase in the electrochemical double-layer capacitance. A change in the capacitance induced a change in the electrical potential of the bilayer, generating electrical energy. The SECH overcomes several challenges of the previous mechano-electrochemical harvester: The harvester had high elasticity (50%), which satisfied the required strain during human motion. The harvester was highly soft (modulus of 5.8 MPa), 103 times lower than that of the previous harvester. The SECH can be applied to a self-powered strain gauge, capable of measuring stationary deformation and low-speed motion. The SECH created a system to examine the configuration of the human body, as demonstrated by the human monitoring sensor from five independent SECH assembled on the hand. Furthermore, the sensing information was simplified through the binarized signal. It can be used to assess the hand configuration for hand signals and sign language.

High-Power Hydro-Actuators Fabricated from Biomimetic Carbon Nanotube Coiled Yarns with Fast Electrothermal Recovery

Bioinspired yarn/fiber structured hydro-actuators have recently attracted significant attention. However, most water-driven mechanical actuators are unsatisfactory because of the slow recovery process and low full-time power density. A rapidly recoverable high-power hydro-actuator is reported by designing biomimetic carbon nanotube (CNT) yarns. The hydrophilic CNT (HCNT) coiled yarn was prepared by storing pre-twist into CNT sheets and subsequent electrochemical oxidation (ECO) treatment. The resulting yarn demonstrated structural stability even when one end was cut off without the possible loss of pre-stored twists. The HCNT coiled yarn actuators provided maximal contractile work of 863 J/kg at 11.8 MPa stress when driven by water. Moreover, the recovery time of electrically heated yarns at a direct current voltage of 5 V was 95% shorter than that of neat yarns without electric heating. Finally, the electrothermally recoverable hydro-actuators showed a high actuation frequency (0.17 Hz) and full-time power density (143.8 W/kg).

Twist-Stabilized, Coiled Carbon Nanotube Yarns with Enhanced Capacitance

Coil-structured carbon nanotube (CNT) yarns have recently attracted considerable attention. However, structural instability due to heavy twist insertion, and inherent hydrophobicity restrict its wider application. We report a twist-stable and hydrophilic coiled CNT yarn produced by the facile electrochemical oxidation (ECO) method. The ECO-treated coiled CNT yarn is prepared by applying low potentiostatic voltages (3.0-4.5 V vs Ag/AgCl) between the coiled CNT yarn and a counter electrode immersed in an electrolyte for 10-30 s. Notably, a large volume expansion of the coiled CNT yarns prepared by electrochemical charge injection produces morphological changes, such as surface microbuckling and large reductions in the yarn bias angle and diameter, resulting in the twist-stability of the dried ECO-treated coiled CNT yarns with increased yarn density. The resulting yarns are well functionalized with oxygen-containing groups; they exhibit extrinsic hydrophilicity and significantly improved capacitance (approximately 17-fold). We quantitatively explain the origin of the capacitance improvement using theoretical simulations and experimental observations. Stretchable supercapacitors fabricated with the ECO-treated coiled CNT yarns show high capacitance (12.48 mF/cm and 172.93 mF/cm², respectively) and great stretchability (80%). Moreover, the ECO-treated coiled CNT yarns are strong enough to be woven into a mask as wearable supercapacitors.

All-in-focus fine needle aspiration biopsy imaging based on Fourier ptychographic microscopy

Context

Cytology is the study of whole cells in diagnostic pathology. Unlike standard histologic thinly sliced specimens, cytologic preparations consist of preparations of whole cells where cells commonly cluster and aggregate. As such, cytology preparations are generally much thicker than histologic slides, resulting in large patches of defocus when examined under the microscope. A diagnostic aggregate of cells often cannot be viewed in focus together, requiring pathologists to continually manipulate the focal plane, complicating the task of accurately assessing the entire cellular aggregate and thus in making a diagnosis. Further, it is extremely difficult to acquire useful uniformly in-focus digital images of cytology preparations for applications such as remote diagnostic evaluations and artificial intelligence models. The predominant current method to address this issue is to acquire digital images at multiple focal planes of the entire slide, which demands long scanning time, complex and expensive scanning systems, and huge storage capacity.

Aims

Here we report a unique imaging method that can acquire cytologic images efficiently and computationally render all-in-focus digital images that are highly compact.

Methods and material

This method applies a metric-based digital refocusing to microscopy data collected with a Fourier ptychographic microscope (FPM). The digitally refocused patches of images are then synthesized into an all-in-focus image.

Results

We report all-in-focus FPM results of thyroid fine needle aspiration (FNA) cytology samples, demonstrating our method’s ability to overcome the height variance of 30 μm caused by cell aggregation, and rendering images at high resolution (corresponds to a standard microscope with objective NA of 0.75) and that are all-in-focus.

Conclusions

This technology is applicable to standard microscopes, and we believe can have an impact on diagnostic accuracy as well as ease and speed of diagnosing challenging specimens. While we focus on cytology slides here, we anticipate this technology’s advantages will translate well for histology applications. This technique also addresses the issue of remote rapid evaluation of cytology preparations. Finally, we believe that by resolving the focus heterogeneity issues in standard digital images, this technique is a critical advance for applying machine learning to cytology specimens.

Wafer-Scale Production of Transition Metal Dichalcogenides and Alloy Monolayers by Nanocrystal Conversion for Large-Scale Ultrathin Flexible Electronics

Two-dimensional (2D) transition metal dichalcogenide (TMD) layers are unit-cell thick materials with tunable physical properties according to their size, morphology, and chemical composition. Their transition of lab-scale research to industrial-scale applications requires process development for the wafer-scale growth and scalable device fabrication. Herein, we report on a new type of atmospheric pressure chemical vapor deposition (APCVD) process that utilizes colloidal nanoparticles as process-scalable precursors for the wafer-scale production of TMD monolayers. Facile uniform distribution of nanoparticle precursors on the entire substrate leads to the wafer-scale uniform synthesis of TMD monolayers with the controlled size and morphology. Composition-controlled TMD alloy monolayers with tunable bandgaps can be produced by simply mixing dual nanoparticle precursor solutions in the desired ratio. We also demonstrate the fabrication of ultrathin field-effect transistors and flexible electronics with uniformly controlled performance by using TMD monolayers.

A Hierarchically Tailored Wrinkled Three-Dimensional Foam for Enhanced Elastic Supercapacitor Electrodes

Recently, three-dimensional (3D) porous foams have been studied, but further improvement in nanoscale surface area and stretchability is required for electronic and energy applications. Herein, a general strategy is reported to form a tailored wrinkling structure on strut surfaces inside a 3D polydimethylsiloxane (PDMS) polymeric foam. Controlled wrinkles are created on the struts of 3D foam through an oxygen plasma treatment to form a bilayer surface of PDMS on uniaxially prestretched 3D PDMS foam, followed by relaxation. After plasma treatment for 1 h and prestretching of 40%, the wrinkled 3D foam greatly improves specific surface area and stretchability by over 60% and 75%, respectively, compared with the pristine 3D PDMS foam. To prove its applicability with improved performances, supercapacitors are prepared by coating a conductive material on the wrinkled 3D foam. The resulting supercapacitors exhibit an increased storage capacity (8.3 times larger), maintaining storage capacity well under stretching up to 50%.

The climate benefits, co-benefits, and trade-offs of green infrastructure: A systematic literature review

Climate change increases risks to natural and human systems. Green infrastructure (GI) has been increasingly recognized as a promising nature-based solution for climate change adaptation, mitigation, and other societal objectives for sustainable development. Although the climate contribution of GI has been extensively addressed in the literature, the linkages between the climate benefits and associated co-benefits and trade-offs remain unclear. We systematically reviewed the evidence from 141 papers, focusing on their climate benefits, relevant co-benefits and trade-offs, and the GI types that provide such climate (co-)benefits. This study presents a comprehensive overview of the links between climate benefits, co-benefits and types of GI, categorized along a green-grey continuum so that researchers/practitioners can find information according to their topic of interest. We further provide an analysis of trade-offs between various GI benefits. 'Bundles' of major co-benefits and trade-offs for each climate benefit can be identified with recommendations for strategies to maximize benefits and minimize trade-offs. To promote climate-resilient pathways through GI, it is crucial for decision-makers to identify opportunities to deliver multiple ecosystem services and benefits while recognizing disservices and trade-offs that need to be avoided or managed.

Bibliometric analysis of manuscript characteristics that influence citations: A comparison of ten major dermatology journals

BACKGROUND

The number of citations an article receives is a reassuring marker for its influence in the academic world.

OBJECTIVE

We aimed to discover characteristics of dermatology articles that may impact their citation.

METHODS

This cross-sectional study collected and analyzed articles published between January and June 2013 from ten highest impact dermatology journals. The study included manuscript characteristics i.e. the length of an article, the presence of visual aids, accessibility, originality, and clarity. Citation analysis statistics required multiple tools such as linear regression, point-biserial correlation, Spearman's rank-order correlation, and Kruskal-Wallis to determine the association between these study variables and the number of citations of articles.

RESULTS

Of 748 articles included in our study, the number of citations ranged from 0 to 814 (median: 18), with weak positive correlations to the length of manuscript (word count: r_s 0.3, p<0.001; pages: r_s 0.3, p<0.001). Having a structured abstract (r_pb -0.15, p<0.001) and increasing number of references (r_s -0.26, p<0.001) showed a negative correlation. Studies originating in North America were associated with higher citations, followed by Europe and Asia (p<0.001). Review articles had a higher number of citations (p<0.001).

CONCLUSIONS

We found that the number of words and the number of pages within a dermatology manuscript had the strongest positive correlation for a higher citation count. The results of this study can benefit authors who may improve the citation of their articles by utilizing this bibliometric study when assembling their manuscript.

Serpentine-pattern effects on the biaxial stretching of percolative graphene nanoflake films

Stretchable strain sensors based on percolative arrangements of conducting nanoparticles are essential tools in stretchable electronics and have achieved outstanding performance. Introducing serpentine patterns for strain-sensing materials is a very effective method for enhancing stretchability with a quantified structural resistance through a simple, reliable, and facile approach. Here, we investigate serpentine-pattern effects in the electrical responses to biaxial stretching for percolative graphene-nanoparticle films. Graphene nanoplatelet films are applied to a stretchable substrate using a facile spray-coating technique, for a variety of serpentine pattern shapes, aspect ratios, pattern frequencies, and number of coatings. The electrical responses after applying biaxial stretching (x-axis and y-axis) are measured and analyzed for comparison. The serpentine patterns that would be suitable for stretchable electrodes, sensitive sensors, and highly stretchable sensors are then identified. This work demonstrates the advantage of using serpentine patterns for stretchable strain sensors and offers guidelines for selecting suitable pattern types for strain sensors in stretchable-electronics applications.