Unmanned aerial vehicles (UAVs) are equipped with optical systems including an infrared (IR) camera such as electro-optical IR (EO/IR), target acquisition and designation sights (TADS), or forward ...looking IR (FLIR). However, images obtained from IR cameras are subject to noise such as dead pixels, lines, and fixed pattern noise. Nonuniformity correction (NUC) is a widely employed method to reduce noise in IR images, but it has limitations in removing noise that occurs during operation. Methods have been proposed to overcome the limitations of the NUC method, such as two-point correction (TPC) and scene-based NUC (SBNUC). However, these methods still suffer from unfixed pattern noise. In this paper, a background registration-based adaptive noise filtering (BRANF) method is proposed to overcome the limitations of conventional methods. The proposed BRANF method utilizes background registration processing and robust principle component analysis (RPCA). In addition, image quality verification methods are proposed that can measure the noise filtering performance quantitatively without ground truth images. Experiments were performed for performance verification with middle wave infrared (MWIR) and long wave infrared (LWIR) images obtained from practical military optical systems. As a result, it is found that the image quality improvement rate of BRANF is 30% higher than that of conventional NUC.
Tracking system is essential for Image Guided Surgery(IGS). The Optical Tracking Sensor(OTS) has been widely used as tracking system for IGS due to its high accuracy and easy usage. However, OTS has ...a limit that tracking fails when occlusion of marker occurs. In this paper, sensor fusion with OTS and Inertial Measurement Unit(IMU) is proposed to solve this problem. The proposed algorithm improves the accuracy of tracking system by eliminating scattering error of the sensor and supplements the disadvantages of OTS and IMU through sensor fusion based on Kalman filter. Also, coordinate axis calibration method that improves the accuracy is introduced. The performed experiment verifies the effectualness of the proposed algorithm.
Image guided surgery using medical robots is becoming popular these days. For image guided surgery, a tracking system is required to provide 6DOF information of patient coordinate, surgical ...instruments and medical robots used in surgery. To provide 6DOF information, a marker has to be attached to the target. However, it is hard to use many markers all together because the markers will take too much space in the surgical area. The tracking system proposed in this study utilizes down sized markers compared to traditional markers by using micro-engraved data-coded pattern with a lens instead of using geometrically specified marker spheres as a tracking target. A tracking system is developed that has a measurement area of 1m to 2.5m from the tracking system. Experiment has been done for surgical navigation using the proposed tracking system and a medical robot.
While an equation of state (EOS) plays a critical role in estimating thermodynamic properties, employing it in the determination of binary interaction parameters is extremely important. In general, ...these parameters can be determined from phase equilibrium data. However, data collection from experiments is a time-consuming and tedious process. In this study, after measuring the excess enthalpies of binary systems containing CO
2
by high-pressure flow isothermal microcalorimetry (IMC), we determined the EOS binary interaction parameters, specifically, the Peng-Robinson EOS binary interaction parameters. These binary interaction parameters obtained by IMC were compared with those obtained by vapor-liquid equilibrium (VLE) experiments. Hence, high-pressure flow IMC appears to be an effective method for the determination of interaction parameters that are used in the estimation of thermodynamic properties. Further, the Flory-Huggins interaction parameters of a binary mixture CO
2
containing with various mole compositions were also estimated by employing high-pressure IMC.
Purpose
In neurosurgery, an image-guided operation is performed to confirm that the surgical instruments reach the exact lesion position. Among the multiple imaging modalities, an X-ray fluoroscope ...mounted on C- or O-arm is widely used for monitoring the position of surgical instruments and the target position of the patient. However, frequently used fluoroscopy can result in relatively high radiation doses, particularly for complex interventional procedures. The proposed system can reduce radiation exposure and provide the accurate three-dimensional (3D) position information of surgical instruments and the target position.
Methods
X-ray and optical stereo vision systems have been proposed for the C- or O-arm. Two subsystems have same optical axis and are calibrated simultaneously. This provides easy augmentation of the camera image and the X-ray image. Further, the 3D measurement of both systems can be defined in a common coordinate space.
Results
The proposed dual stereoscopic imaging system is designed and implemented for mounting on an O-arm. The calibration error of the 3D coordinates of the optical stereo and X-ray stereo is within 0.1 mm in terms of the mean and the standard deviation. Further, image augmentation with the camera image and the X-ray image using an artificial skull phantom is achieved.
Conclusion
As the developed dual stereoscopic imaging system provides 3D coordinates of the point of interest in both optical images and fluoroscopic images, it can be used by surgeons to confirm the position of surgical instruments in a 3D space with minimum radiation exposure and to verify whether the instruments reach the surgical target observed in fluoroscopic images.
Purpose
Image-guided surgery using medical robots supports surgeons by providing critical real-time feedback information, such as surgical instrument tracking, patient-specific models, and the use of ...surgery robots. An image-guided surgery system based on afocal optics was developed to overcome the problems associated with conventional optical tracking systems.
Method
An optical tracking system was developed that utilizes afocal optics. Instead of using geometrically specified marker spheres as tracking targets, the proposed system uses a marker with a lens and a micro-engraved data-coded pattern. A position and orientation-tracking algorithm was developed to utilize the observed afocal images of the marker patterns. The marker used in this tracking system can be manufactured in a smaller size than traditional optical tracker markers, and the accuracy of the proposed tracking system has significant potential for improvement due to its focused and highly magnified image. The system was tested in vitro on an optical bench with position and orientation measurement experiments using a commercial optical tracker, Polaris Vicra (NDI Corp.) for comparison.
Results
The afocal optical system provided accuracy in position and orientation that was equal or better than a commercial optical tracker system, and provided a high degree of consistency during in vitro testing. The position error was 219
μ
m, and the orientation error was 0.093
∘
.
Conclusion
An afocal optical tracker is feasible and potentially advantageous for surgical navigation, as it is expected to have fewer occlusions and provide greater efficiency for coordinate matching and tracking of patient-specific models, surgical instruments, and surgery robots. This promising new system requires in vivo testing.
Silicon is considered a most promising anode material for overcoming the theoretical capacity limit of carbonaceous anodes. The use of nanomethods has led to significant progress being made with Si ...anodes to address the severe volume change during (de)lithiation. However, less progress has been made in the practical application of Si anodes in commercial lithium‐ion batteries (LIBs). The drastic increase in the energy demands of diverse industries has led to the co‐utilization of Si and graphite resurfacing as a commercially viable method for realizing high energy. Herein, we highlight the necessity for the co‐utilization of graphite and Si for commercialization and discuss the development of graphite/Si anodes. Representative Si anodes used in graphite‐blended electrodes are covered and a variety of strategies for building graphite/Si composites are organized according to their synthetic methods. The criteria for the co‐utilization of graphite and Si are systematically presented. Finally, we provide suggestions for the commercialization of graphite/Si combinations.
Why graphite and Si? The practical realization of Si anodes is still a big challenge, but the co‐utilization of graphite and Si could solve this. This Review provides insight into the commercialization of Si anodes, emphasizing the necessity for the co‐utilization of graphite and Si and the development of graphite/Si anodes as well as giving a detailed discussion on their electrochemical behavior and critical factors.
Endothelial dysfunction is one of the main age‐related arterial phenotypes responsible for cardiovascular disease (CVD) in older adults. This endothelial dysfunction results from decreased ...bioavailability of nitric oxide (NO) arising downstream of endothelial oxidative stress. In this study, we investigated the protective effect of anthocyanins and the underlying mechanism in rat thoracic aorta and human vascular endothelial cells in aging models. In vitro, cyanidin‐3‐rutinoside (C‐3‐R) and cyanidin‐3‐glucoside (C‐3‐G) inhibited the d‐galactose (d‐gal)‐induced senescence in human endothelial cells, as indicated by reduced senescence‐associated‐β‐galactosidase activity, p21, and p16INK4a. Anthocyanins blocked d‐gal‐induced reactive oxygen species (ROS) formation and NADPH oxidase activity. Anthocyanins reversed d‐gal‐mediated inhibition of endothelial nitric oxide synthase (eNOS) serine phosphorylation and SIRT1 expression, recovering NO level in endothelial cells. Also, SIRT1‐mediated eNOS deacetylation was shown to be involved in anthocyanin‐enhanced eNOS activity. In vivo, anthocyanin‐rich mulberry extract was administered to aging rats for 8 weeks. In vivo, mulberry extract alleviated endothelial senescence and oxidative stress in the aorta of aging rats. Consistently, mulberry extract also raised serum NO levels, increased phosphorylation of eNOS, increased SIRT1 expression, and reduced nitrotyrosine in aortas. The eNOS acetylation was higher in the aging group and was restored by mulberry extract treatment. Similarly, SIRT1 level associated with eNOS decreased in the aging group and was restored in aging plus mulberry group. These findings indicate that anthocyanins protect against endothelial senescence through enhanced NO bioavailability by regulating ROS formation and reducing eNOS uncoupling.
Aging is known for its correlation with increased protein acetylation rates and the decline of sirtuin‐1 (SIRT1) deacetylation activity. This study demonstrated that anthocyanin‐rich mulberry extract reduces oxidative stress in aging vasculature and attenuates endothelial dysfunction through reversed inhibition of endothelial nitric oxide synthase (eNOS), serine phosphorylation, and SIRT1 expression, recovering NO level in senescence.
Content delivery success in wireless caching helper networks depends mainly on cache-based channel selection diversity and network interference. For given channel fading and network geometry, both ...channel selection diversity and network interference dynamically vary according to what and how the caching helpers cache at their finite storage space. We study probabilistic content placement (or caching placement) to desirably control cache-based channel selection diversity and network interference in a stochastic wireless caching helper network, with sophisticated considerations of wireless fading channels, interactions among multiple users, such as interference and loads at caching helpers, and arbitrary memory size. Using stochastic geometry, we derive optimal caching probabilities in the closed form to maximize the average success probability of content delivery and propose an efficient algorithm to find the solution in a noise-limited network. In an interference-limited network, based on a lower bound of the average success probability of content delivery, we find near-optimal caching probabilities in the closed form to control the channel selection diversity and the network interference. We numerically verify that the proposed content placement is superior to other comparable content placement strategies.
Metformin is the first-line pharmacotherapy for treating type 2 diabetes mellitus (T2DM); however, its mechanism of modulating glucose metabolism is elusive. Recent advances have identified the gut ...as a potential target of metformin. As patients with metabolic disorders exhibit dysbiosis, the gut microbiome has garnered interest as a potential target for metabolic disease. Henceforth, studies have focused on unraveling the relationship of metabolic disorders with the human gut microbiome. According to various metagenome studies, gut dysbiosis is evident in T2DM patients. Besides this, alterations in the gut microbiome were also observed in the metformin-treated T2DM patients compared to the non-treated T2DM patients. Thus, several studies on rodents have suggested potential mechanisms interacting with the gut microbiome, including regulation of glucose metabolism, an increase in short-chain fatty acids, strengthening intestinal permeability against lipopolysaccharides, modulating the immune response, and interaction with bile acids. Furthermore, human studies have demonstrated evidence substantiating the hypotheses based on rodent studies. This review discusses the current knowledge of how metformin modulates T2DM with respect to the gut microbiome and discusses the prospect of harnessing this mechanism in treating T2DM.
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