- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Multispectral optoacoustic tomography (MSOT) for imaging the particle size-dependent intratumoral distribution of polymeric micelles
摘要： Purpose: This study proposes the utilization of multispectral optoacoustic tomography (MSOT) to investigate the intratumoral distribution of polymeric micelles and effect of size on the biodistribution and antitumor efficacy (ATE). Materials and methods: Docetaxel and/or optoacoustic agent-loaded polymeric micelles (with diameters of 22, 48, and 124 nm) were prepared using amphiphilic block copolymers poly (ethylene glycol) methyl ether-block-poly (D,L lactide) (PEG2000–PDLLAx). Subcutaneous 4T1 tumor-bearing mice were monitored with MSOT imaging and IVIS? Spectrum in vivo live imaging after tail vein injection of micelles. The in vivo results and ex vivo confocal imaging results were then compared. Next, ATE of the three micelles was found and compared. Results: We found that MSOT imaging offers spatiotemporal and quantitative information on intratumoral distribution of micelles in living animals. All the polymeric micelles rapidly extravasated into tumor site after intravenous injection, but only the 22-nm micelle preferred to distribute into the inner tumor tissues, leading to a superior ATE than that of 48- and 124-nm micelles. Conclusion: This study demonstrated that MSOT is theranostically a powerful imaging modality, offering quantitative information on size-dependent spatiotemporal distribution patterns after the extravasation of nanomedicine from tumor blood vessels.
关键词： intratumoral distribution,MSOT,multispectral optoacoustic tomography,in vivo imaging,tumor model,particle size,polymeric micelle
更新于2025-09-23 15:23:52
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[IEEE 2018 Signal Processing: Algorithms, Architectures, Arrangements, and Applications (SPA) - Poznan, Poland (2018.9.19-2018.9.21)] 2018 Signal Processing: Algorithms, Architectures, Arrangements, and Applications (SPA) - Hardware implementation of the Gaussian Mixture Model foreground object segmentation algorithm working with ultra-high resolution video stream in real-time
摘要： In this paper a hardware implementation of the Gaussian Mixture Model algorithm for background modelling and foreground object segmentation is presented. The proposed vision system is able to handle video stream with resolution up to 4K (3840x2160 pixels) and 60 frames per second. Moreover, the constraints caused by memory bandwidth limit are also discussed and a few different solutions to tackle this issue have been considered. The designed modules have been verified on the ZCU102 development board with Xilinx Zynq UltraScale+ MPSoC device. Additionally, the computing performance and power consumption have been estimated.
关键词： FPGA,4K video,background modelling,real-time processing,GPU,Gaussian Mixture Model,foreground object segmentation
更新于2025-09-23 15:23:52
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Effect of laser forming on mechanical properties of multiple-phase steels by using a thermal–microstructure–mechanical model
摘要： Based on a forming temperature-controlled mixed strain-hardening law, a temperature-controlled thermal–microstructure–mechanical model was developed to predict the deformation in ferrite–martensite dual-phase steel before and after complex laser forming. Phase transformation in dual phase steel was predicted by coupling a kinetic transformation model with the developed model during laser forming. The corresponding algorithm of the constitutive model was used in three-dimensional finite element method to simulate the material deformation and mechanical properties during the laser forming. The simulated results agree well with the experimental results. Laser forming influences the mechanical properties of the material significantly, leads to bending deformation of the scanned sample and induces a ferrite-to-martensite transformation. The influence of scanning line number on the tensile strength and bending deformation of the scanned specimen was investigated. The tensile strength and bending angle are related positively to the number of scanning lines on the sample.
关键词： Stress-strain curve,Phase transformation,Thermal–microstructure–mechanical model,Sheet metal,Laser forming
更新于2025-09-23 15:23:52
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[Advanced Structured Materials] Materials Design and Applications II Volume 98 || Orientation of the Digital Model for SLA 3D Printing and Its Influence on the Accuracy of the Manufactured Physical Objects for Micro- and Nano Technologies
摘要： In modern mechanical engineering, there is increased need to find solutions for fast manufacturing of real prototypes. One of these is the fast-growing up-to-date CAD/CAM/CAE system enabling to create digital prototypes. Using CAD systems the conceptual design is analyzed and tested before producing the real prototype. This reduces the compliance costs for manufacturing of the physical models and tooling as well as the production time of the prototype is lessened several times. With the development of technology, and especially in medicine, it is necessary to produce prototypes that can be obtained relatively quickly and meet the requirements of accuracy. Rapid prototyping technologies have such capabilities that they can reproduce digital models with their manufacturer’s precision. To determine the accuracy of printing, a SLA system is used. To determine the accuracy of printing, a SLA system is used. One of the peculiarities of making a detail by this method is the appearance of distortions in the initial stage of construction at large rectilinear plots. In order to determine the minimum printing deviations, a strategy for printing prototype models at a different slope of 0°–90° was used. Patterns are made with coordinate networks, enabling post-print deviations to be evaluated by matching the digital model. The present study will be useful in developing prototype models for micro and nanotechnology in mechanical engineering and medicine, providing a solution for their optimal location with minimal deviations.
关键词： CAD system,Material for casting,Photopolymer,Micro model,SLA 3D printing
更新于2025-09-23 15:23:52
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A detail preserving variational model for image Retinex
摘要： In this paper, we propose a detail preserving variational model for Retinex to simultaneously estimate the illumination and the reflectance from an observed image. Most previous models use the log-transform as pretreatment which results in loss of details in reflectance. From this observation, a detail preserving variational method is proposed for better decomposition. Different from the log-transform based models, the proposed model performs the decomposition directly in the image domain. Mathematically, we prove the existence of a solution for the proposed model. Numerically, we derive an efficient iterative algorithm by utilizing alternating direction method of multipliers (ADMM) method. Experimental results demonstrate the effectiveness of the proposed method. Compared with other closely related Retinex methods, the proposed method achieves competitive results on both subjective and objective assessments.
关键词： Reflectance,Retinex,Illumination,Variational model,Image decomposition
更新于2025-09-23 15:23:52
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One-loop structure of the photon propagator in the standard model extension
摘要： Radiative corrections to the photon propagator from the electroweak sector are studied in the context of the minimal Lorentz- and CPT-violating standard model extension, with a focus on the Yukawa, Higgs, and gauge sectors. The most general Lorentz-violating ghost sector dictated by Becchi-Rouet-Stora-Tyutin symmetry and renormalization theory is derived. We stress the introduction of a Lorentz-violating nonlinear gauge that greatly simplifies both the Higgs-sector extension and the gauge-sector extension, which can be very helpful in radiative corrections. At one loop, these sectors contribute to the CPT-even part of the photon propagator, which is characterized by the Riemann-type tensor (kF)αβμν. Exact results for the contributions to the SO(1,3) irreducible parts of (kF)αβμν, namely, the Weyl-type tensor (?kF)αβμν, the Ricci-type tensor (kF)αβ, and the curvature-type scalar kF, are presented. In the Yukawa sector, with general flavor-violating effects, all of the one-loop contributions are ultraviolet finite, but most of them are unobservable due to finite renormalization of the field, the electric charge, (?kF)αβμν, and (kF)αβ. The only observable effect is a contribution proportional to (kF)αβ that emerges via a dimension-six term that is both observer and gauge invariant. In the Higgs and gauge sectors, all of the irreducible parts of the corresponding Riemann-type tensors receive divergent contributions, so they are observable. The only finite contribution corresponds to the previously mentioned dimension-six term. By thinking of these contributions as a radiative correction to the renormalized tensors, and assuming that both effects are of the same order of magnitude, bounds from vacuum birefringence are derived and compared with results in the literature. Bounds on contributions proportional to (kF)αβ, which are innocuous to birefringence, are also derived using limits imposed on the renormalized tensor from the Laser Interferometer Gravitational-Wave Observatory data. We compare these bounds with those already existing in the literature. The beta functions associated with the (?kF)αβμν and (kF)αβ tensors are derived.
关键词： Lorentz violation,radiative corrections,photon propagator,standard model extension,beta functions,CPT violation
更新于2025-09-23 15:23:52
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[IEEE 2018 17th International Conference on Ground Penetrating Radar (GPR) - Rapperswil, Switzerland (2018.6.18-2018.6.21)] 2018 17th International Conference on Ground Penetrating Radar (GPR) - Full Waveform Inversion of Cross-hole Radar Data Using Envelope Objective Function
摘要： The full waveform inversion (FWI) has been used as a high resolution imaging method for cross-hole radar inversion implementation, however, when FWI is used to process field data, it encounters a variety of problems and causes the inversion to fall into a local minimum. One problem is that the GPR data lacks low frequency information. An effective way is to provide an accurate initial model for FWI. The fact is that the underground media is unknown which results in difficult to obtain ideal result in FWI. By means of the derivation of the objective function, the gradient formula of the envelope waveform inversion (EWI) is derived by taking the derivation of the EWI misfit function with respect to the model parameter. By comparing the inversion results of the EWI with that of the traditional FWI without low-frequency information in the observed GPR data, we found that the EWI can effectively restore missing low-frequency information and has better inversion ability for low-frequency missing data.
关键词： cross-hole radar,envelope,full waveform inversion,low frequency component,initial model
更新于2025-09-23 15:23:52
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[IEEE 2018 25th IEEE International Conference on Image Processing (ICIP) - Athens, Greece (2018.10.7-2018.10.10)] 2018 25th IEEE International Conference on Image Processing (ICIP) - Image-Based 3D Model Retrieval for Indoor Scenes by Simulating Scene Context
摘要： We propose a single image-based 3D model retrieval method for indoor scenes. By simulating the scene context of the input image, our method is able to handle several challenging scenarios featuring cluttered backgrounds and severe occlusions. To use our system, the user only needs to drag a few semantic bounding boxes for the query objects. The proposed approach then retrieves the most similar 3D models from the ShapeNet model repository, and aligns them with the corresponding objects automatically. This requires that the 3D models are represented by calibrated view-dependent visual elements learned from the rendered views. With the estimated occlusion relationships, the rendered model images are stacked at the corresponding locations to simulate the scene context. By conducting matching between these synthesized scenes and the input image, the most similar 3D models under the approximate poses are retrieved. Moreover, we show that the retrieving time can be significantly reduced based on a novel greedy algorithm. Experimental results demonstrate the effectiveness of our proposed method.
关键词： 3D model retrieval,cluttered background,scene context,occlusion relationship
更新于2025-09-23 15:23:52
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Ultrafast electron-lattice thermalization in copper and other noble metal nanoparticles
摘要： Using time-resolved ultrafast pump-probe spectroscopy we investigated the electron-lattice energy transfer in small copper nanospheres with diameters ranging from 3.2 to 23 nm, either embedded in a glass or dispersed in a solvent. Electron-lattice scattering rate is shown to increase with size reduction, in agreement with our previous results obtained on gold and silver nanoparticles in the low excitation regime. We attribute this effect to the reduction of the screening efficiency of electron–phonon interactions close to the nanoparticle surface. To understand the discrepancy between the results on the electron-lattice scattering in different metals reported in the literature (reduction, no dependence or increase with nanoparticle size), we discuss the experimental conditions required for the accurate determination of electron-lattice energy transfer time from time-resolved investigations in the weak and strong excitation regimes and present power-dependent experiments on gold nanospheres in solution. Our findings are derived from a theoretical analysis based on the two-temperature model predictions and on a complete modeling of the nanoparticle transient extinction cross-section through the resolution of Boltzmann equation in the presence of hot electrons.
关键词： pump-probe spectroscopy,copper nanoparticles,electron-lattice interactions,two-temperature model,ultrafast electron dynamics
更新于2025-09-23 15:23:52
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[Lecture Notes in Computer Science] Euro-Par 2018: Parallel Processing Workshops Volume 11339 (Euro-Par 2018 International Workshops, Turin, Italy, August 27-28, 2018, Revised Selected Papers) || Modeling and Optimizing Data Transfer in GPU-Accelerated Optical Coherence Tomography
摘要： Signal processing of optical coherence tomography (OCT) has become a bottleneck for using OCT in medical and industrial applications. Recently, GPUs gained more importance as compute device to achieve video frame rate of 25 frames/s. Therefore, we develop a CUDA implementation of an OCT signal processing chain: We focus on reformulating the signal processing algorithms in terms of high-performance libraries like CUBLAS and CUFFT. Additionally, we use NVIDIA’s stream concept to overlap computations and data transfers. Performance results are presented for two Pascal GPUs and validated with a derived performance model. The model gives an estimate for the overall execution time for the OCT signal processing chain, including compute and transfer times.
关键词： GPU,OCT,CUDA,Performance model
更新于2025-09-23 15:23:52