Multiwavelength Achromatic Deflector in the Visible Using a Single-Layer Freeform Metasurface.

Deflectors are essential for modulating beam direction in optical systems but often face form factor issues or chromatic aberration with conventional optical elements, such as prisms, mirrors, and diffractive/holographic optical elements. Despite recent efforts to address such issues using metasurfaces, their practicality remains limited due to operation wavelengths in the near-infrared or the fabrication difficulties inherent in the multilayer scheme. Here, we propose a novel single-layer metasurface achieving multiwavelength chromatic aberration-free deflection across the visible spectrum by employing the robust freeform design strategy to simplify the fabrication process. By properly selecting diffraction orders for red, green, and blue wavelengths to achieve identical wavelength-diffraction-order products, the metasurface deflects light at a consistent angle of 41.3° with a high efficiency. The coupled Bloch mode analysis explains the physical properties, and experimental fabrication and characterization confirm its effectiveness. This approach holds potential for various applications such as AR/VR, digital cameras, and high-quality optical systems.

Light-Triggerable and Gate-Tunable Negative Differential Resistance in Small Molecules Heterojunction.

Negative differential resistance (NDR), a phenomenon in which the current decreases when the applied voltage is increased, is attracting attention as a unique electrical property. Here, we propose a broad spectral photo/gate cotunable channel switching NDR (CS-NDR) device. The proposed CS-NDR device has superior linear gate-tunable NDR behavior and highly reproducible properties compared to the previously reported NDR devices, as the fundamental mechanism of the CS-NDR device is directly related to a charge transport channel switching by the linear increase of the applied drain voltage. We also experimentally demonstrate that the photoinduced NDR behavior of the CS-NDR device was derived from the grain boundaries of dinaphtho[2;3-b:2',3'-f]-thieno[3,2-b]thiophene. Furthermore, this work produces a 9 × 9 CS-NDR device array composed of 81 devices, providing the reproducibility and uniformity of the CS-NDR device. Finally, we successfully demonstrate the detection of text images with 81 CS-NDR devices using the proposed photo/gate cotunable NDR behavior.

Coronal plane in opportunistic screening of osteoporosis using computed tomography: comparison with axial and sagittal planes.

OBJECTIVE: To compare the coronal plane with axial and sagittal planes in opportunistic screening of osteoporosis using computed tomography (CT). MATERIALS AND METHODS: A total of 100 patients aged ≥ 50 years who underwent both lumbar spine CT and dual-energy X-ray absorptiometry within 3 months were included. Osteoporosis was diagnosed based on dual-energy X-ray absorptiometry results. The CT number was measured at the center of the vertebral body in coronal, axial, and sagittal planes. To compare the coronal plane with axial and sagittal planes in diagnosing osteoporosis, the areas under the receiver operating characteristic curve (AUC) were compared and intraclass correlation coefficient (ICC) was calculated. The optimal cutoff values were calculated using Youden's index. RESULTS: The AUC of the coronal plane (0.80; 95% confidence interval [CI], 0.71-0.89) was not significantly different from that of the axial plane (0.78; 95% CI, 0.68-0.87; P = 0.39) and that of the sagittal plane (0.78; 95% CI, 0.69-0.87; P = 0.68). Excellent concordance rates were observed between coronal and axial planes with ICC of 0.95 (95% CI, 0.92-0.96) and between coronal and sagittal planes with ICC of 0.93 (95% CI, 0.85-0.96). The optimal cutoff values for the coronal, axial, and sagittal planes were 110, 112, and 112 HU, respectively. CONCLUSION: The coronal plane does not significantly differ from axial and sagittal planes in opportunistic screening of osteoporosis. Thus, the coronal plane as well as axial and sagittal planes can be used interchangeably in measuring bone mineral density using CT.

Optimal Control for a Superconducting Hybrid MagLev Transport System with Multirate Multisensors in a Smart Factory.

Recently, magnetic levitation systems have been applied and studied in various industrial fields. In particular, in-tracktype magnetic levitation conveyor systems are actively studied since they can effectively minimize electromagnetic effects in processes that require a highly clean environment. In this type of system, diverse and multiple sensors are structurally required so that the control performance of an integrated system is primarily governed by the slowest measuring sensor. This paper proposes a multisensor fusion compensator to integrate the outputs obtained from various sensors into one output with the single fastest time rate. Since the state of the system is estimated at a fast time rate, the optimal controller also guarantees fast performance and stability. The computation of electromagnetic fields and the control performance of the considered superconducting hybrid system were analyzed using a computer simulation based on finite element methods.

Comparative Analysis of Integrated Filtering Methods Using UWB Localization in Indoor Environment.

This research delves into advancing an ultra-wideband (UWB) localization system through the integration of filtering technologies (moving average (MVG), Kalman filter (KF), extended Kalman filter (EKF)) with a low-pass filter (LPF). We investigated new approaches to enhance the precision and reduce noise of the current filtering methods-MVG, KF, and EKF. Using a TurtleBot robotic platform with a camera, our research thoroughly examines the UWB system in various trajectory situations (square, circular, and free paths with 2 m, 2.2 m, and 5 m distances). Particularly in the square path trajectory with the lowest root mean square error (RMSE) values (40.22 mm on the X axis, and 78.71 mm on the Y axis), the extended Kalman filter with low-pass filter (EKF + LPF) shows notable accuracy. This filter stands out among the others. Furthermore, we find that integrated method using LPF outperforms MVG, KF, and EKF consistently, reducing the mean absolute error (MAE) to 3.39% for square paths, 4.21% for circular paths, and 6.16% for free paths. This study highlights the effectiveness of EKF + LPF for accurate indoor localization for UWB systems.

NSrp70 is a lymphocyte-essential splicing factor that controls thymocyte development.

Alternative pre-mRNA splicing is a critical step to generate multiple transcripts, thereby dramatically enlarging the proteomic diversity. Thus, a common feature of most alternative splicing factor knockout models is lethality. However, little is known about lineage-specific alternative splicing regulators in a physiological setting. Here, we report that NSrp70 is selectively expressed in developing thymocytes, highest at the double-positive (DP) stage. Global splicing and transcriptional profiling revealed that NSrp70 regulates the cell cycle and survival of thymocytes by controlling the alternative processing of various RNA splicing factors, including the oncogenic splicing factor SRSF1. A conditional-knockout of Nsrp1 (NSrp70-cKO) using CD4Cre developed severe defects in T cell maturation to single-positive thymocytes, due to insufficient T cell receptor (TCR) signaling and uncontrolled cell growth and death. Mice displayed severe peripheral lymphopenia and could not optimally control tumor growth. This study establishes a model to address the function of lymphoid-lineage-specific alternative splicing factor NSrp70 in a thymic T cell developmental pathway.

Solution-processed zirconium acetylacetonate charge-trap layer for multi-bit nonvolatile thin-film memory transistors.

The charge trap property of solution-processed zirconium acetylacetonate (ZAA) for solution-processed nonvolatile charge-trap memory (CTM) transistors is demonstrated. Increasing the annealing temperature of the ZAA from room temperature (RT) to 300°C in ambient, the carbon double bonds within the ZAA decreases. The RT-dried ZAA for the p-type organic-based CTM shows the widest threshold voltage shift (∆VTH ≈ 80 V), four distinct VTHs for a multi-bit memory operation and retained memory currents for 103 s with high memory on- and off-current ratio (IM,ON/IM,OFF ≈ 5Ⅹ104). The n-type oxide-based CTM (Ox-CTM) also shows a ∆VTH of 14 V and retained memory currents for 103 s with IM,ON/IM,OFF ≈ 104. The inability of the Ox-CTM to be electrically erasable is well explained with simulated electrical potential contour maps. It is deduced that, irrespective of the varied solution-processed semiconductor used, the RT-dried organic ZAA as CTL shows the best memory functionality in the fabricated CTMs. This implies that the high carbon double bonds in the low-temperature processed ZAA CTL are very useful for low-cost multi-bit CTMs in flexible electronics.

Trampoline Stiffness Estimation by Using Robotic System for Quantitative Evaluation of Jumping Exercises.

Trampolines are recognized as a valuable tool in exercise and rehabilitation due to their unique properties like elasticity, rebound force, low-impact exercise, and enhancement of posture, balance, and cardiopulmonary function. To quantitatively assess the effects of trampoline exercises, it is essential to estimate factors such as stiffness, elements influencing jump dynamics, and user safety. Previous studies assessing trampoline characteristics had limitations in performing repetitive experiments at various locations on the trampoline. Therefore, this research introduces a robotic system equipped with foot-shaped jigs to evaluate trampoline stiffness and quantitatively measure exercise effects. This system, through automated, repetitive movements at various locations on the trampoline, accurately measures the elastic coefficient and vertical forces. The robot maneuvers based on the coordinates of the trampoline, as determined by its torque and position sensors. The force sensor measures data related to the force exerted, along with the vertical force data at X, Y, and Z coordinates. The model's accuracy was evaluated using linear regression based on Hooke's Law, with Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and Correlation Coefficient Squared (R-squared) metrics. In the analysis including only the distance between X and the foot-shaped jigs, the average MAE, RMSE, and R-squared values were 17.9702, 21.7226, and 0.9840, respectively. Notably, expanding the model to include distances in X, Y, and between the foot-shaped jigs resulted in a decrease in MAE to 15.7347, RMSE to 18.8226, and an increase in R-squared to 0.9854. The integrated model, including distances in X, Y, and between the foot-shaped jigs, showed improved predictive capability with lower MAE and RMSE and higher R-squared, indicating its effectiveness in more accurately predicting trampoline dynamics, vital in fitness and rehabilitation fields.

Fault Diagnosis Method for Human Coexistence Robots Based on Convolutional Neural Networks Using Time-Series Data Generation and Image Encoding.

This paper proposes fault diagnosis methods aimed at proactively preventing potential safety issues in robot systems, particularly human coexistence robots (HCRs) used in industrial environments. The data were collected from durability tests of the driving module for HCRs, gathering time-series vibration data until the module failed. In this study, to apply classification methods in the absence of post-failure data, the initial 50% of the collected data were designated as the normal section, and the data from the 10 h immediately preceding the failure were selected as the fault section. To generate additional data for the limited fault dataset, the Wasserstein generative adversarial networks with gradient penalty (WGAN-GP) model was utilized and residual connections were added to the generator to maintain the basic structure while preventing the loss of key features of the data. Considering that the performance of image encoding techniques varies depending on the dataset type, this study applied and compared five image encoding methods and four CNN models to facilitate the selection of the most suitable algorithm. The time-series data were converted into image data using image encoding techniques including recurrence plot, Gramian angular field, Markov transition field, spectrogram, and scalogram. These images were then applied to CNN models, including VGGNet, GoogleNet, ResNet, and DenseNet, to calculate the accuracy of fault diagnosis and compare the performance of each model. The experimental results demonstrated significant improvements in diagnostic accuracy when employing the WGAN-GP model to generate fault data, and among the image encoding techniques and convolutional neural network models, spectrogram and DenseNet exhibited superior performance, respectively.

Minimally Invasive Open Reduction and Maintenance Technique for Anterior Sacrococcygeal Dislocation: A Case Report.

Anterior dislocation of the coccyx is rare, but it can occur due to trauma. Conservative treatment is usually performed. However, dislocation reduction may be required to control severe pain in the acute phase or to prevent chronic complications. If manual reduction fails, open reduction is required. The extent of the incision and the method used to maintain the reduction should be considered during open reduction. A 56-year-old male patient experienced a dislocation of the sacrococcygeal joint after falling backwards. Despite conservative treatment, the patient complained of persistent pain during sitting and when using the bathroom. A manual reduction was attempted but failed. We performed joystick reduction via minimal incision and maintained the reduction using a one-strand trans-osseous suture passing through the skin. The patient was advised to use a soft cushion when sitting or lying down for four weeks after surgery. The supine position was not restricted. The patient's symptoms significantly improved after surgery. At the 6-month follow-up, the sacrococcygeal joint showed good alignment and no surgical complications occurred. During the treatment of sacrococcygeal dislocation, the rapid alleviation of acute pain and minimizing potential complications are key points. If open reduction is needed, the minimally invasive reduction technique with a one-strand trans-osseous suture may offer patient satisfaction and a good surgical outcome.

Three-Dimensional Foot Position Estimation Based on Footprint Shadow Image Processing and Deep Learning for Smart Trampoline Fitness System.

In the wake of COVID-19, the digital fitness market combining health equipment and ICT technologies is experiencing unexpected high growth. A smart trampoline fitness system is a new representative home exercise equipment for muscle strengthening and rehabilitation exercises. Recognizing the motions of the user and evaluating user activity is critical for implementing its self-guided exercising system. This study aimed to estimate the three-dimensional positions of the user's foot using deep learning-based image processing algorithms for footprint shadow images acquired from the system. The proposed system comprises a jumping fitness trampoline; an upward-looking camera with a wide-angle and fish-eye lens; and an embedded board to process deep learning algorithms. Compared with our previous approach, which suffered from a geometric calibration process, a camera calibration method for highly distorted images, and algorithmic sensitivity to environmental changes such as illumination conditions, the proposed deep learning algorithm utilizes end-to-end learning without calibration. The network is configured with a modified Fast-RCNN based on ResNet-50, where the region proposal network is modified to process location regression different from box regression. To verify the effectiveness and accuracy of the proposed algorithm, a series of experiments are performed using a prototype system with a robotic manipulator to handle a foot mockup. The three root mean square errors corresponding to X, Y, and Z directions were revealed to be 8.32, 15.14, and 4.05 mm, respectively. Thus, the system can be utilized for motion recognition and performance evaluation of jumping exercises.

Subtrochanteric Insufficiency Fracture Occurring 5 Years after Surgery at the Steinmann Pin Insertion Site for Fracture Reduction.

Background and Objectives: Steinmann pins are commonly used in orthopedics, with a low rate of complications. However, thermal osteonecrosis may occur when a pin is inserted using a drill. There have been no reports on late-onset fractures at the Steinmann pin insertion site. Materials and Methods: A 32-year-old man who underwent surgery for a femoral shaft fracture 5 years ago complained of proximal thigh pain 1 month after the removal of the internal device. On physical examination, the patient showed a limping gait due to pain, and tenderness was observed on the lateral aspect of the proximal thigh. Magnetic resonance imaging was performed because the symptoms did not improve, despite conservative treatment. A new fracture line was observed in the lateral cortical bone of the proximal femur. It was found that a fracture occurred at the site where the Steinmann pin was inserted for a closed reduction at the time of the first operation. The patient was instructed to limit weight bearing and to use crutches while walking. Parathyroid hormone was additionally administered to promote bone formation. Results: Six months after diagnosis, a complete union was achieved at the subtrochanteric fracture site, and the patient's pain subsided. Conclusions: A fracture that occurs as a late onset at the provisional Steinmann pin insertion site is an extremely rare complication; however, orthopedic surgeons must consider this possibility and make more efforts to lower the occurrence of thermal damage. In addition, if the patient complains of pain in the region where the pin was inserted after surgery, surgeons should spare no effort to determine whether a new fracture has occurred.

Systematic Control of Negative Transconductance in Organic Heterojunction Transistor for High-Performance, Low-Power Flexible Ternary Logic Circuits.

Organic multi-valued logic (MVL) circuits can substantially improve the data processing efficiency in highly advanced wearable electronics. Organic ternary logic circuits can be implemented by utilizing the negative transconductance (NTC) of heterojunction transistors (H-TRs). To achieve high-performance organic ternary logic circuits, the range of NTC in H-TRs must be optimized in advance to ensure the well-defined intermediate logic state in ternary logic inverters (T-inverters). Herein, a simple and efficient strategy, which enables the systematic control of the range and position of NTC in H-TRs is presented. Each thickness of p-/n-type semiconductor in H-TRs is adjusted to control the channel conductivity. Furthermore, asymmetric source/drain (S/D) electrode structure is newly developed for H-TRs, which can adjust the amount of hole and electron injection, independently. Based on the semiconductor thickness variation and asymmetric S/D electrodes, the T-inverter exhibits full-swing operation with three distinguishable logic states, resulting in unprecedentedly high static noise margin (≈48% of the ideal value). Moreover, a flexible T-inverter with an ultrathin polymer dielectric is demonstrated, whose operating voltage is less than 8 V. The proposed strategy is fully compatible with the conventional integrated circuit design, which is highly desirable for broad applicability and scalability for various types of T-inverter production.

Absorptive metasurface color filters based on hyperbolic metamaterials for a CMOS image sensor.

Metasurface color filters (MCFs) have attracted considerable attention thanks to their compactness and functionality as a candidate of an optical element in a miniaturized image sensor. However, conventional dielectric and plasmonic MCFs that have focused on color purity and efficiency cannot avoid reflection in principle, which degrades image quality by optical flare. Here, we introduce absorptive-type MCFs through truncated-cone hyperbolic metamaterial absorbers. By applying a particle swarm optimization method to design multiple parameters simultaneously, the proposed MCF is theoretically and numerically demonstrated in perceptive color on CIELAB and CIEDE2000 with suppressed-reflection. Then, a color filter array is numerically proven in 255 nm of sub-pixel pitch.

Synergistic Effects of Self-Assembled Monolayers in Solution-Processed 6,13-Bis(triisopropylsilylethynyl)Pentacene Transistors.

Organic semiconductors are highly interface-sensitive, and therefore chemical functionalization using self-assembled monolayers (SAMs) is often adopted to tailor their properties. This study clarifies the synergistic effects of electrode and dielectric SAMs on the behavior of solution-processed organic field-effect transistors (OFETs). Utilization of a self-consistent device model enables a physically robust treatment of the measured electrical characteristics of the OFETs, thus providing highly reliable materials, interface, morphology, and transport parameters. These parameters are further extended and correlated to build a comprehensive picture on trap energy and injection-transport relationship, finally revealing a set of fundamental insights into chemically modified OFETs.

Policosanol attenuates Pi-induced calcification via AMPK-mediated INSIGs expression in rat VSMCs.

Policosanol is a hypocholesterolemic derived from sugar cane and corn that downregulates blood cholesterol levels. It can further lower blood pressure and reduce liver inflammation. Policosanol can also affect vascular calcification, however, its molecular mechanisms are not well understood. This study investigated the effect of policosanol on vascular calcification and its molecular mechanism. Policosanol decreased the expression of inorganic phosphate (Pi)-induced osteogenic genes such as distal-less homeobox 5 (Dlx5) and runt-related transcription factor 2 (Runx2). In addition, following policosanol treatment, adenosine monophosphate-activated protein kinase (AMPK) phosphorylation increased in a time-dependent manner. The constitutively active form of AMPK (CA-AMPK) dramatically suppressed Pi-induced Dlx5 and Runx2 protein levels. Inactivation of AMPK using compound C (Com. C; AMPK inhibitor) recovered policosanol-suppressed Alizarin Red S staining levels. Insulin-induced genes (INSIGs) were induced by CA-AMPK, their overexpression suppressed Pi-induced Dlx5 and Runx2 expression. Taken together, the results demonstrate that policosanol inhibits Pi-induced vascular calcification by regulating AMPK-induced INSIG expression in vascular smooth muscle cells.

Dielectric Metalens: Properties and Three-Dimensional Imaging Applications.

Recently, optical dielectric metasurfaces, ultrathin optical skins with densely arranged dielectric nanoantennas, have arisen as next-generation technologies with merits for miniaturization and functional improvement of conventional optical components. In particular, dielectric metalenses capable of optical focusing and imaging have attracted enormous attention from academic and industrial communities of optics. They can offer cutting-edge lensing functions owing to arbitrary wavefront encoding, polarization tunability, high efficiency, large diffraction angle, strong dispersion, and novel ultracompact integration methods. Based on the properties, dielectric metalenses have been applied to numerous three-dimensional imaging applications including wearable augmented or virtual reality displays with depth information, and optical sensing of three-dimensional position of object and various light properties. In this paper, we introduce the properties of optical dielectric metalenses, and review the working principles and recent advances in three-dimensional imaging applications based on them. The authors envision that the dielectric metalens and metasurface technologies could make breakthroughs for a wide range of compact optical systems for three-dimensional display and sensing.

OLED Opportunity in Healthcare With the Pulse Oximeter.

The emergence of ultra-thin, flexible, and bright OLED devices has ignited tremendous interest in their potential as a light source in pulse oximetry, a well-established method to monitor pulse rate and blood oxygen level.

Predicting Endovascular Treatment Outcomes in Acute Vertebrobasilar Artery Occlusion: A Model to Aid Patient Selection from the ASIAN KR Registry.

Background The decision to perform endovascular treatment (EVT) for stroke related to vertebrobasilar occlusion (VBO) remains controversial. Purpose To identify preprocedural predictors of good outcomes and to develop a model to aid patient selection for VBO. Materials and Methods For this retrospective study using a Korean multicenter registry, a predictive model for good outcomes (modified Rankin scale score, 0-2) was generated based on a derivation sample of patients with VBO (January 2011-February 2016). Preprocedural parameters, including onset-to-puncture time, infarct volume, occlusion type as a surrogate marker of intracranial atherosclerotic stenosis-related occlusion or embolic occlusion (truncal-type occlusion vs branching site occlusion), and collateral status, were analyzed. Continuous variables were dichotomized based on receiver operating characteristic analysis. Multiple logistic regression analysis was performed to generate a predictive model. The model was internally validated with the bootstrap method and was externally validated with a single-center sample (April 2016-December 2018). Results A predictive model was generated from 71 patients (mean age, 67 years ± 11 [standard deviation]; 41 [58%] men) and was externally validated in 32 patients (mean age, 72 years ± 13; 19 [59%] men). The composite of initial DW imaging volume of less than 10 mL (odds ratio [OR], 19.3; 95% confidence interval [CI]: 3.0, 126.4; P = .002), onset-to-puncture time of less than 8 hours (OR, 8.7; 95% CI: 1.8, 42.0; P = .007), and branching-site occlusion (OR, 6.1; 95% CI: 1.5, 26.0; P = .01) could be used to predict good outcomes, with a median area under the receiver operating characteristic curve of 0.86 (interquartile range [IQR], 0.77-0.95; bootstrap optimism-corrected C statistic, 0.837) in the derivation sample and 0.78 (IQR, 0.62-0.95) in the validation sample. Results failed to show an association between collateral status and outcome (P = .67). Conclusion When selecting patients with vertebrobasilar occlusion for endovascular treatment, the combination of onset-to-puncture time of less than 8 hours, initial infarct volume of less than 10 mL, and presence of branching-site occlusions is indicative of a good outcome. © RSNA, 2020 Online supplemental material is available for this article.

Doublet metalens design for high numerical aperture and simultaneous correction of chromatic and monochromatic aberrations.

Metalens is one of the most prominent applications among metasurfaces since it gives possibilities to replace the conventional lenses for compactness and multi-functionalities. Recently, many studies have been demonstrated to overcome the aberrations of the metalenses for high performance practical applications. Previous studies have used the methods that control the dispersion of meta-atoms for correcting chromatic aberrations and use doublet platform for correcting monochromatic aberrations. Despite these studies and the large demands for simultaneous correction of the aberrations in high numerical aperture metalens, the simultaneous correction has not been demonstrated yet. In this paper, we report the doublet metalens design with high numerical aperture which corrects longitudinal chromatic aberration and four monochromatic aberrations including spherical aberration, coma, astigmatism, and field curvature simultaneously for the three primary visible colors. Based on the novel doublet platform, the multi-wavelength targeted correction lens and geometric phase lens with color filtering functionality are utilized. Our doublet metalens has numerical apertures of 0.33, 0.38, and 0.47 for 445 nm, 532 nm, and 660 nm, respectively. The back focal length of our doublet metalens remains nearly 360 µm for target wavelengths and incident angles up to 30 degrees.