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Detectable depth of unexposed parathyroid glands using near-infrared autofluorescence imaging in thyroid surgery
No full textBackgroundNear-infrared light can penetrate the fat or connective tissues overlying the parathyroid gland (PG), enabling early localization of the PG by near-infrared autofluorescence (NIRAF) imaging. However, the depth at which the PG can be detected has not been reported. In this study, we investigated the detectable depth of unexposed PGs using NIRAF during thyroidectomy. Materials and methodsFifty-one unexposed PGs from 30 consecutive thyroidectomy patients, mapped by an experienced surgeon (K.D. Lee) with the use of NIRAF imaging, were included. For NIRAF detection of PGs, a lab-built camera imaging system was used. Detectable depths of the unexposed PGs were measured using a Vernier caliper. The NIRAF images were classified as faint or bright depending on whether a novice could successfully interpret the image as showing the PG. Data on variables that may affect detectable depth and NIRAF intensity were collected. ResultsDetectable depth ranged between 0.35 and 3.05 mm, with a mean of 1.23 +/- 0.73 mm. The average NIRAF intensity of unexposed PGs was 3.13 au. After dissection of the overlying tissue, the intensity of the exposed PG increased to 4.88 au (p < 0.001). No difference in NIRAF intensity between fat-covered (3.27 +/- 0.90 au) and connective tissue-covered PGs (3.00 +/- 1.23 au) was observed (p = 0.369). PGs covered by fat tissue (depth: 1.77 +/- 0.67 mm) were found at deeper locations than those covered by connective tissue (depth: 0.70 +/- 0.21 mm) (p < 0.001). The brightness of images of the faint group (2.14 +/- 0.48 au) was on average 1.24 au lower than that of the bright group (3.38 +/- 1.04 au) (p = 0.001). A novice successfully localized 80.4% of the unexposed PGs. Other variables did not significantly affect detectable depth. ConclusionUnexposed PGs could be mapped using NIRAF imaging at a maximum depth of 3.05 mm and an average depth of 1.23 mm. A novice was able to localize the PGs before they were visible to the naked eye at a high rate. These results can be used as reference data for localization of unexposed PGs in thyroid surgery
A Highly Reliable Molybdenum Disulfide-Based Synaptic Memristor Using a Copper Migration-Controlled Structure
No full textMemristors are drawing attention as neuromorphic hardware components because of their non-volatility and analog programmability. In particular, electrochemical metallization (ECM) memristors are extensively researched because of their linear conductance controllability. Two-dimensional materials as switching medium of ECM memristors give advantages of fast speed, low power consumption, and high switching uniformity. However, the multistate retention in the switching conductance range for the long-term reliable neuromorphic system has not been achieved using two-dimensional materials-based ECM memristors. In this study, the copper migration-controlled ECM memristor showing excellent multistate retention characteristics in the switching conductance range using molybdenum disulfide (MoS2) and aluminum oxide (Al2O3) is proposed. The fabricated device exhibits gradual resistive switching with low switching voltage (<0.5 V), uniform switching (sigma/mu similar to 0.07), and a wide switching range (>12). Importantly, excellent reliabilities with robustness to cycling stress and retention over 10(4) s for more than 5-bit states in the switching conductance range are achieved. Moreover, the contribution of the Al2O3 layer to the retention characteristic is investigated through filament morphology observation using transmission electron microscopy (TEM) and copper migration component analysis. This study provides a practical approach to developing highly reliable memristors with exceptional switching performance
Dual Interface Passivation in Mixed-Halide Perovskite Solar Cells by Bilateral Amine
No full textPoor crystallization and nonradiative recombination at charge transfer interfaces are the main challenges in scaling up mixed-halide perovskite solar cells. If the theoretical open-circuit voltage (VOC) limit is to be achieved, surface defects at the perovskite surface and grain boundaries must be suppressed by passivation. However, it is unavoidable that the passivation material will strongly bind to the perovskite without disrupting the three-dimensional (3D) symmetry. When primary amines are introduced into perovskite precursors, they generate a quasi-2D/3D perovskite with poor photocurrent charge transport properties. To address these constraints, we show that secondary amine (N,N '- dimethyl-1,3-propanediammonium dichloride) can stabilize the bulk phase of perovskite materials, passivating both surfaces and improving the charge carrier lifetime. In particular, a record-high VOC of 1.27 V is achieved at an optimal band gap of 1.63 eV. Our findings will help to guide future efforts to improve the performance and stability of perovskite solar cells
Heterogeneous stacking of reduced graphene oxide on ZnO nanowires for NO2 gas sensors with dramatically improved response and high sensitivity
No full textGraphene or two-dimensional materials have been intensively studied as a new generation of gas sensing ma-terials due to their large specific surface area and high mobility. However, fabrication processes for oxide and 2D materials lead to non-uniform structures of flakes of graphene or its derivatives and oxide nanowire, are randomly suspended to devices, resulting in poor and unrepeatable sensing performances. Here, we report on the heterogeneous stacked interface of reduced graphene oxide (rGO) on the surface of ZnO nanowires and their demonstration as a NO2 gas sensor. Compared to the conventional surface decoration using noble metals such as Au, Ag, and Pd, the present sensor shows excellent sensing performances including 22 times faster response behavior. Moreover, this interface-based rGO-ZnO gas sensor showed outperforming sensitivity and recovery time to reported 2D and 2D/oxide based gas sensor. The active sites of rGO are more favorable for chemisorption of oxygen molecules due to functional groups on rGO surfaces. Moreover, the gas-sensing mechanism is firstly elucidated by the finite-difference time-domain (FDTD) simulation, confirming that mono-to-few layers of rGO on ZnO act a role of bridge, facilitating the migration of electrons from ZnO to NO2, leading to higher increment of depletion region and corresponding sensor response. Our approaches may offer the new opportunities and strategies for highly sensitive and fast recoverable 2D materials/oxide hybrid sensors
Sensor drift compensation for gas mixture classification in batch experiments
No full textSensor drift in batch experiments is a well-known problem in mixed gas classification. In batch experiments, gas sensors can be easily affected by environmental covariates that hinder mixed gas classification. To address this problem, we propose a novel end-to-end deep learning model comprising a drift-compensation module and classification module. Utilizing the nonlinear relationship between sensor readings and environmental covariates, the drift-compensation module corrects the drifted sensor readings in batch experiments by minimizing a scatteredness-based fitness function. The corrected values are then fed into the classification module. To train the proposed model, which involves optimizing two different objectives simultaneously, the hypernetwork-based optimization approach with the stochastic gradient descent is employed. We validated the effectiveness of the proposed method for mixed gas classification using synthetic and real gas mixture data collected from the UCI machine learning repository
Perceived by Counselors of the Functional Elements of the Online Psychological Counseling Platform
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Influence of cellulose micro-fibers on hydration characteristics of cementless UHPC using CaO-activated GGBFS
No full textThis study aimed to investigate the influence of natural cellulose fibers (NCFs) on improving the hydration characteristics of cementless ultra-high performance concrete (UHPC) using CaO-activated ground granulated blast furnace slag (GGBFS). The NCFs were added in a saturated condition as an internal-curing agent so as to supply additional water to the UHPC matrix and subsequently increase the reactivity of unhydrated phases. To evaluate the hydration characteristics, saturated NCFs were added at 0 to 1.5 wt% of the GGBFS plus CaO. TGA and FTIR analyses showed that, as the amount of NCFs increased, the formation of hydration products was improved as evidenced by an increase in heat of hydration, indicating that more reactions of unhydrated phases occurred. Similarly, morphologies of the samples revealed the formation of hydration products on and near the surfaces of the NCFs due to the additional water exerted during the process of internal curing. Moreover, the compressive and tensile strengths were not compromised by the incorporation of weak and flexible NCFs, but rather a slight improvement was observed with a certain content of NCFs
Design and field trial of EmotionFrame: exploring self-journaling experiences in homes for archiving personal feelings about daily events
No full textCapturing people???s spontaneous thoughts or daily emotions in their everyday living space can be difficult and can pose a psychological burden from a clinical standpoint. To address this issue, we have developed EmotionFrame, which allows users to archive their daily experiences by recording videos of their current thoughts and emotions at home. EmotionFrame serves as a journaling device, and the parameters for journaling have been determined based on a depression assessment model. This study explores the benefits of users??? recording feelings about their daily events, which can also help with assessing depressive mood with the journaling data. Our three-week in-field study with eight participants showed that EmotionFrame could be integrated into participants??? daily routines based on their previous diary-writing habits. In addition, its harmonious frame shape fits in with the everyday environment. Being able to engage in spontaneous journaling in private spaces ??? and in a way that allowed them to see themselves ??? prompted the study participants to effectively record their sincere thoughts and emotions during the archiving process
In Situ Construction of Ta:Fe2O3@CaFe2O4 Core-Shell Nanorod p-t-n Heterojunction Photoanodes for Efficient and Robust Solar Water Oxidation
No full textIn order to ameliorate the poor charge transfer characteristics of hematite (alpha-Fe2O3) photoanodes for photoelectrochemical (PEC) water splitting, heterojunction formation with pCaFe2O4 is attempted. Here, we report the in situ construction of a highly crystalline p-CaFe2O4 shell on the surface of n-Ta:Fe2O3 nanorods to form Ta:Fe2O3@CaFe2O4 core-shell nanorod p-t-n heterojunction photoanodes with a transition layer (t) between them by a combined strategy of hybrid microwave annealing (HMA) and in situ Ta doping. The successful fabrication of the elaborate heterostructure is due to effective crystallization of p-CaFe2O4 by HMA and prevention of Ca diffusion by already doped Ta atoms in hematite. The optimized Ta:Fe2O3@CaFe2O4 photoanode loaded with the FeNiOx cocatalyst achieves a photocurrent density of 2.70 mA cm-2, a low onset potential of 0.63 VRHE, and long-time stability in PEC water oxidation at 1.23 VRHE under 100 mW cm-2 solar irradiation, which represent marked improvements over bare hematite photoanodes and already reported hematite-based heterojunction photoanodes
Flux-Driven Josephson Parametric Amplifier Fabricated Using the Nb/AlOx/Nb Trilayer Process
No full textIn this paper, we report a flux-driven Josephson parametric amplifier (JPA) fabricated using the Nb/AlOx/Nb Josephson junction process. The JPA consists of a parallel-plate type coupling capacitor and quarter-wavelength resonator terminated with a DC-SQUID. We adopt a simple process using well-established Nb trilayer technology. The overall configuration time of the Nb-based JPA can be shortened by measuring resonant frequency and its bias dependence in liquid helium. Amplification of the pre-tested device was demonstrated, showing a gain of 20 dB in a -3 dB bandwidth of 17 MHz in a 10 mK dilution fridge