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Development and evaluation of realistic optical cell models for rapid and label-free cell assay by diffraction imaging
摘要： Methods for rapid and label-free cell assay are highly desired in life science. Single-shot diffraction imaging presents strong potentials to achieve this goal as evidenced by past experimental results using methods such as polarization diffraction imaging flow cytometry. We present here a platform of methods toward solving these problems and results of optical cell model (OCM) evaluations by calculations and analysis of cross-polarized diffraction image (p-DI) pairs. Four types of realistic OCMs have been developed with two prostate cell structures and adjustable refractive index parameters to investigate the effects of cell morphology and index distribution on calculated p-DI pairs. Image patterns have been characterized by a gray-level co-occurrence matrix (GLCM) algorithm and 4 GLCM parameters and linear depolarization ratio δL have been selected to compare calculated against measured data of prostate cells. Our results show that the irregular shapes of and heterogeneity in refractive index (RI) distributions for organelles play significant roles in the spatial distribution of scattered light by cells in comparison to the average RI values and their differences among the organelles. Discrepancies in GLCM and δL parameters between calculated and measured p-DI data provide useful insight for understanding light scattering by single cells and improving OCM.
关键词： cell models,light scattering,diffraction imaging,cell analysis
更新于2025-09-10 09:29:36
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Nonequilibrium Environment Dynamics in a Frequency-Dependent Polarizable Embedding Model
摘要： Hybrid quantum mechanical/molecular mechanical (QM/MM) models are some of the most powerful and computationally feasible approaches to account for solvent effects or more general environmental perturbations on quantum chemical systems. In their more recent formulations (known as polarizable embedding) they can account for electrostatic and mutual polarization effects between the QM and the MM subsystems. In this paper, a polarizable embedding scheme based on induced dipoles that is both able to describe electron evolution of the embedded QM system in an efficient manner as well as to capture the frequency dependent behavior of the solvent is proposed, namely ωMMPol. The effects of this frequency dependent solvent on a time-dependent model system — the Rabi oscillations of H+2 in a resonant field — are considered. The solvent is shown to introduce only mild perturbations when the excitation frequencies of the solvent and the solute are off-resonant. However, the dynamics of the H+2 are fundamentally changed in the presence of a near-resonant excitation solvent. The effectiveness of ωMMPol to simulating realistic chemical systems is demonstrated by capturing charge transfer dynamics within a solvated system.
关键词： charge transfer dynamics,polarizable embedding,Rabi oscillations,QM/MM models,frequency-dependent polarizability,electron dynamics
更新于2025-09-10 09:29:36
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Space lidar observations constrain longwave cloud feedback
摘要： Some of the most challenging questions in atmospheric science relate to how clouds will respond as the climate warms. On centennial scales, the response of clouds could either weaken or enhance the warming due to greenhouse gas emissions. Here we use space lidar observations to quantify changes in cloud altitude, cover, and opacity over the oceans between 2008 and 2014, together with a climate model with a lidar simulator to also simulate these changes in the present-day climate and in a future, warmer climate. We find that the longwave cloud altitude feedback, found to be robustly positive in simulations since the early climate models and backed up by physical explanations, is not the dominant longwave feedback term in the observations, although it is in the model we have used. These results suggest that the enhanced longwave warming due to clouds might be overestimated in climate models. These results highlight the importance of developing a long-term active sensor satellite record to reduce uncertainties in cloud feedbacks and prediction of future climate.
关键词： space lidar observations,climate models,climate warming,longwave cloud radiative effect,cloud feedback
更新于2025-09-10 09:29:36
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Medieval Archaeology Under the Canopy with LiDAR. The (Re)Discovery of a Medieval Fortified Settlement in Southern Italy
摘要： Despite the recognized effectiveness of LiDAR in penetrating forest canopies, its capability for archaeological prospection can be strongly limited in areas covered by dense vegetation for the detection of subtle remains scattered over morphologically complex areas. In these cases, an important contribution to improve the identification of topographic variations of archaeological interest is provided by LiDAR-derived models (LDMs) based on relief visualization techniques. In this paper, diverse LDMs were applied to the medieval site of Torre Cisterna to the north of Melfi (Southern Italy), selected for this study because it is located on a hilly area with complex topography and thick vegetation cover. These conditions are common in several places of the Apennines in Southern Italy and prevented investigations during the 20th century. Diverse LDMs were used to obtain maximum information and to compare the performance of both subjective (through visual inspections) and objective (through their automatic classification) methods. To improve the discrimination/extraction capability of archaeological micro-relief, noise filtering was applied to Digital Terrain Model (DTM) before obtaining the LDMs. The automatic procedure allowed us to extract the most significant and typical features of a fortified settlement, such as the city walls and a tower castle. Other small, subtle features attributable to possible buried buildings of a habitation area have been identified by visual inspection of LDMs. Field surveys and in-situ inspections were carried out to verify the archaeological points of interest, microtopographical features, and landforms observed from the DTM-derived models, most of them automatically extracted. As a whole, the investigations allowed (i) the rediscovery of a fortified settlement from the 11th century and (ii) the detection of an unknown urban area abandoned in the Middle Ages.
关键词： LiDAR-Derived Models,medieval archaeology,Cisterna (Melfi),archaeological microtopography,LiDAR,castle,Basilicata,automatic feature extraction
更新于2025-09-10 09:29:36
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Performance evaluation of the symmetrical quasi-classical dynamics method based on Meyer-Miller mapping Hamiltonian in the treatment of site-exciton models
摘要： The symmetrical quasi-classical dynamics method based on the Meyer-Miller mapping Hamiltonian (MM-SQC) shows the great potential in the treatment of the nonadiabatic dynamics of complex systems. We performed the comprehensive benchmark calculations to evaluate the performance of the MM-SQC method in various site-exciton models with respect to the accurate results of quantum dynamics method multilayer multiconfigurational time-dependent Hartree (ML-MCTDH). The parameters of the site-exciton models are chosen to represent a few of prototypes used in the description of photoinduced excitonic dynamics processes in photoharvesting systems and organic solar cells, which include the rather broad situations with the fast or slow bath and different system-bath couplings. When the characteristic frequency of the bath is low, the MM-SQC method performs extremely well, and it gives almost the identical results to those of ML-MCTDH. When the fast bath is considered, the deviations exist between the MM-SQC and ML-MCTDH results if the high-frequency bath modes are improperly treated by the classical manner. When the so-called adiabatic renormalization was employed to construct the reduced Hamiltonian by freezing high-frequency modes, the MM-SQC dynamics can give the results comparable to the ML-MCTDH ones. Thus, the MM-SQC method itself provides reasonable results in all test site-exciton models, while the proper treatments of the bath modes must be employed. The possible dependence of the MM-SQC dynamics on the different initial sampling methods for the nuclear degrees of freedom is also discussed.
关键词： nonadiabatic dynamics,ML-MCTDH,site-exciton models,symmetrical quasi-classical dynamics,Meyer-Miller mapping Hamiltonian
更新于2025-09-10 09:29:36
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[IEEE 2018 XXIIIrd International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED) - Tbilisi, Georgia (2018.9.24-2018.9.27)] 2018 XXIIIrd International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED) - Physical Channel Models for Emerging Wireless Communication Systems
摘要： This tutorial introduction to the modeling of RF wireless communication channels is aimed at readers in the diffraction and scattering community, who have no background in radio-frequency wireless communication systems. It clarifies the reasoning behind the choice of parameters used in channel modeling, their utility, and their relationship to the physical phenomena taking place within the channel. The distinguishing features of the mm-wave wireless channel, expected to be deployed in future 5G cellular systems, wireless networks, and Internet-of-Things, are briefly summarized, which highlight the need for developing mm-wave channel models.
关键词： mm-wave channels,physical channel models,Wireless channel models,channel parameters
更新于2025-09-09 09:28:46
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An approach to spin-resolved molecular gas microscopy
摘要： Ultracold polar molecules are an ideal platform for studying many-body physics with long-range dipolar interactions. Experiments in this field have progressed enormously, and several groups are pursuing advanced apparatus for manipulation of molecules with electric fields as well as single-atom-resolved in situ detection. Such detection has become ubiquitous for atoms in optical lattices and tweezer arrays, but has yet to be demonstrated for ultracold polar molecules. Here we present a proposal for the implementation of site-resolved microscopy for polar molecules, and specifically discuss a technique for spin-resolved molecular detection. We use numerical simulation of spin dynamics of lattice-confined polar molecules to show how such a scheme would be of utility in a spin-diffusion experiment.
关键词： quantum gas microscopy,quantum simulation,ultracold molecules,single-molecule control,dipolar spin models,optical lattices
更新于2025-09-09 09:28:46
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High-speed quantitative 3D imaging by dual-illumination holographic microscopy
摘要： A new blood flow imaging (BFI) technique using digital holography with double illumination of the sample is proposed. We imaged the moving red blood cells (RBCs) using a two microscope objective lenses setup. The setup consists in a larger angle of separation (90 (cid:1)) between the two illumination beams, allowing a wider angular rotation at good z resolution. Moreover, the setup geometry allows an easier displacement of the sample in all directions. Results show that this technique is able to perform phase-shifting reconstruction for the two beams at the same time which is more suitable for the future implementation of live 3D holography. Experimental results are carried out for the verification of the effectiveness of the proposed technique on a zebrafish larvae sample.
关键词： preclinical models,red blood cells,fish embryo,holography,microcirculation
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE International Conference on Consumer Electronics - Asia (ICCE-Asia) - JeJu, Korea (South) (2018.6.24-2018.6.26)] 2018 IEEE International Conference on Consumer Electronics - Asia (ICCE-Asia) - Image Pattern Classification Using MFCC and HMM
摘要： We propose a novel method for recognizing temporally or spatially varying patterns using MFCC (mel-frequency ceptral coefficient) and HMM (hidden Markov model). MFCC and HMM have been adopted as de facto standard for speech recognition. It is very useful time-domain signals with temporally varying characteristics. Most images have characteristical patterns, so HMM is expected to model them very efficiently. We suggest efficient pattern classification algorithm with MFCC and HMM, and showed its improved performance in MNIST and fashion MNIST databases.
关键词： Hidden Markov Models (HMMs),Discrete Cosine Transform (DCT),Mixed National Institute of Standards and Technology (MNIST),Mel-Frequency Cepstral Coefficients (MFCC)
更新于2025-09-09 09:28:46
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[IEEE 2018 International Conference on Communication and Signal Processing (ICCSP) - Chennai, India (2018.4.3-2018.4.5)] 2018 International Conference on Communication and Signal Processing (ICCSP) - Early Identification of Fire by Utilization of Camera
摘要： The paper gives a knowledge to flame identification calculations utilizing picture preparing. Aside from various enhanced methods, a streamlined approach might be adequate for everyday reconnaissance. This primarily goes for limiting the time taken for distinguishing proof of a flare-up of flame and its administration. The essential thought of the proposed of flame identification is to embrace a RGB (red, green, blue) demonstrate based chromatic and turmoil estimation for extricating fire-pixels and smoke-pixels. The choice capacity of flame pixel predominantly derived by the force and immersion of R part. The proposed technique is tried with a few differing fire pictures on an Intel i5 processor with 4 GB RAM and the trial comes about are very promising. The proposed technique demonstrated a decent execution of about normal 85% identification rate without false positive, contrasted and alternate strategies with the settled edge esteems.
关键词： gray-scale,frames,color models,thresholding,edge detection,Binary
更新于2025-09-09 09:28:46