2D Projection Research Articles

Enhancing Philtrum Morphology Using Fat Grafting Combined with Percutaneous Rigottomy in Repaired Unilateral Cleft Lip.

Improving the philtrum morphology of patients with a secondary cleft lip deformity has been a challenge in cleft care. Combining fat grafting with percutaneous rigottomy has been advocated for treatment of volumetric deficiency associated with a scarred recipient site. This study assessed the outcome of synchronous fat grafting and rigottomy for improvement of cleft philtrum morphology. Consecutive young adult patients ( n = 13) with a repaired unilateral cleft lip who underwent fat grafting combined with rigottomy expansion technique for enhancement of philtrum morphology were included. Preoperative and postoperative three-dimensional facial models were used for three-dimensional morphometric analyses including philtrum height, projection, and volume parameters. Lip scar was qualitatively judged by a panel composed by two blinded external plastic surgeons using a 10-point visual analogue scale. Three-dimensional morphometric analysis revealed a significant (all P < 0.05) postoperative increase of the lip height-related measurements for cleft philtrum height, noncleft philtrum height, and central lip length parameters, with no difference ( P > 0.05) between cleft and noncleft sides. The postoperative three-dimensional projection of the philtral ridges was significantly ( P < 0.001) larger in cleft (1.01 ± 0.43 mm) than in noncleft sides (0.51 ± 0.42 mm). The average philtrum volume change was 1.01 ± 0.68 cm 3 , with an average percentage fat graft retention of 43.36% ± 11.35%. The panel assessment revealed significant ( P < 0.001) postoperative scar enhancement for the qualitative rating scale, with mean preoperative and postoperative scores of 6.69 ± 0.93 and 7.88 ± 1.14, respectively. Synchronous fat grafting and rigottomy improved philtrum length, projection, and volume and lip scar in patients with repaired unilateral cleft lip. Therapeutic, IV.

Active radiation measurements over one solar cycle with two DOSTEL instruments in the Columbus laboratory of the International Space Station

Two DOSimetry TELescopes (DOSTELs) have been measuring the radiation environment in the Columbus module of the International Space Station (ISS) since 2009 in the frame of the DOSIS and DOSIS 3D projects. Both instruments have measured the charged particle flux rate and dose rates in a telescope geometry of two planar silicon detectors. The radiation environment in the ISS orbit is mostly composed by galactic cosmic radiation (GCR) and its secondary radiation and protons from the inner radiation belt in the South Atlantic Anomaly (SAA) with sporadic contributions of solar energetic particles at high latitudes. The data presented in this work cover two solar activity minima and corresponding GCR intensity maxima in 2009 and 2020 and the solar activity maximum and corresponding GCR intensity minimum in 2014/2015. Average dose rates measured in the Columbus laboratory in the ISS orbit from GCR and SAA are presented separately. The data is analyzed with respect to the effective magnetic shielding and grouped into different cut-off rigidity intervals. Using only measurements in magnetically unshielded regions at low cut-off rigidity and applying a factor for the geometrical shielding of the Earth, absorbed dose rates and dose equivalent rates in near-Earth interplanetary space are estimated for the years 2009 to 2022.

Motion Correction for Separate Mandibular and Cranial Movements in Cone Beam CT Reconstructions.

Patient motions are a repeatedly reported phenomenon in oral and maxillofacial cone beam CT scans, leading to reconstructions of limited usability. In certain cases, independent movements of the mandible induce unpredictable motion patterns. Previous motion correction methods are not able to handle such complex cases of patient movements. Our goal was to design a combined motion estimation and motion correction approach for separate cranial and mandibular motions, solely based on the 2D projection images from a single scan. Our iterative three-step motion correction algorithm models the two articulated motions as independent rigid motions. First of all, we segment cranium and mandible in the projection images using a deep neural network. Next, we compute a 3D reconstruction with the poses of the object's trajectories fixed. Third, we improve all poses by minimizing the projection error while keeping the reconstruction fixed. Step two and three are repeated alternately. We find that our marker-free approach delivers reconstructions of up to 85% higher quality, with respect to the projection error, and can improve on already existing techniques, which model only a single rigid motion. We show results of both synthetic and real data created in different scenarios. The reconstruction of motion parameters in a real environment was evaluated on acquisitions of a skull mounted on a hexapod, creating a realistic, easily reproducible motion profile. The proposed algorithm consistently enhances the visual quality of motion impaired CBCT scans, thus eliminating the need for a re-scan in certain cases, considerably lowering radiation dosage for the patient. It can flexibly be used with differently sized regions of interest and is even applicable to localtomography. This article is protected by copyright. All rights reserved.

UNIVERSITY STUDENTS’ ATTITUDES TOWARDS STEAM VIA A THEMATIC 3D DESIGN PROJECT

The development of STEAM education has captured researchers’ attention due to its advantages for students’ learning and interest in related subjects, specifically in kindergarten to grade 12 (K-12) educational settings. However, there is limited research on the inclusion of STEAM in higher education, and what university students think as they are on the professional training track. This study aimed to examine university students’ attitudes towards STEAM via a 3D design project. Twenty-seven college students participated in this study. A questionnaire and focus group interviews were administered at the end of the course to uncover the students’ learning enjoyment, conceptions of STEAM learning, and intentions of STEAM future design/work involvement. The results show that the students enjoyed the 3D STEAM project regardless of their performance. High-performance students had higher conceptions of STEAM learning after the project. All of the students highly agreed that they could integrate interdisciplinary knowledge into their 3D designs. With regard to future intentions, they generally did not show an active attitude towards STEAM involvement. The students’ learning enjoyment in the STEAM project did not have a strong positive correlation with their future intentions. Findings from this study could offer inspiration for art-oriented courses that look for potential interdisciplinary integration and expression in STEAM. Keywords: attitudes towards STEAM, university students, STEM, 3D design

Use of high-speed angiography HSA-derived boundary conditions and Physics Informed Neural Networks (PINNs) for comprehensive estimation of neurovascular hemodynamics.

Physics-informed neural networks (PINNs) and computational fluid dynamics (CFD) have both demonstrated an ability to derive accurate hemodynamics if boundary conditions (BCs) are known. Unfortunately, patient-specific BCs are often unknown, and assumptions based upon previous investigations are used instead. High speed angiography (HSA) may allow extraction of these BCs due to the high temporal fidelity of the modality. We propose to investigate whether PINNs using convection and Navier-Stokes equations with BCs derived from HSA data may allow for extraction of accurate hemodynamics in the vasculature. Imaging data generated from in vitro 1000 fps HSA, as well as simulated 1000 fps angiograms generated using CFD were utilized for this study. Calculations were performed on a 3D lattice comprised of 2D projections temporally stacked over the angiographic sequence. A PINN based on an objective function comprised of the Navier-Stokes equation, the convection equation, and angiography-based BCs was used for estimation of velocity, pressure and contrast flow at every point in the lattice. Imaging-based PINNs show an ability to capture such hemodynamic phenomena as vortices in aneurysms and regions of rapid transience, such as outlet vessel blood flow within a carotid artery bifurcation phantom. These networks work best with small solution spaces and high temporal resolution of the input angiographic data, meaning HSA image sequences represent an ideal medium for such solution spaces. The study shows the feasibility of obtaining patient-specific velocity and pressure fields using an assumption-free data driven approach based purely on governing physical equations and imaging data.

Accurate real space iterative reconstruction (RESIRE) algorithm for tomography

Tomography has made a revolutionary impact on the physical, biological and medical sciences. The mathematical foundation of tomography is to reconstruct a three-dimensional (3D) object from a set of two-dimensional (2D) projections. As the number of projections that can be measured from a sample is usually limited by the tolerable radiation dose and/or the geometric constraint on the tilt range, a main challenge in tomography is to achieve the best possible 3D reconstruction from a limited number of projections with noise. Over the years, a number of tomographic reconstruction methods have been developed including direct inversion, real-space, and Fourier-based iterative algorithms. Here, we report the development of a real-space iterative reconstruction (RESIRE) algorithm for accurate tomographic reconstruction. RESIRE iterates between the update of a reconstructed 3D object and the measured projections using a forward and back projection step. The forward projection step is implemented by the Fourier slice theorem or the Radon transform, and the back projection step by a linear transformation. Our numerical and experimental results demonstrate that RESIRE performs more accurate 3D reconstructions than other existing tomographic algorithms, when there are a limited number of projections with noise. Furthermore, RESIRE can be used to reconstruct the 3D structure of extended objects as demonstrated by the determination of the 3D atomic structure of an amorphous Ta thin film. We expect that RESIRE can be widely employed in the tomography applications in different fields. Finally, to make the method accessible to the general user community, the MATLAB source code of RESIRE and all the simulated and experimental data are available at https://zenodo.org/record/7273314.

Ultrahigh-density 3D holographic projection by scattering-assisted dynamic holography

Computer-generated holography offers a promising route to three-dimensional (3D) video displays. To realize a realistic-looking 3D display, the critical challenge is to create a 3D hologram that enables high-density multi-plane projection with full depth control. However, two long-existing issues in current digital holographic techniques, low axial resolution and high inter-plane crosstalk, prevent fine depth control and therefore limit the ultimate quality. Here, we report 3D scattering-assisted dynamic holography (3D-SDH) that further breaks the depth-control limit of the state-of-the-art method. Our approach achieves orders of magnitude improvement in axial resolution and greatly suppresses crosstalk, enabling ultrahigh-density 3D holographic projection. Moreover, 3D-SDH enables dynamic 3D vectorial projections via phase-only holograms. The concept is validated through both simulations and experiments, where dynamic projections of 3D point-cloud objects onto high-density successive planes are demonstrated. Our work opens perspectives for 3D holographic technology with ultra-fine depth control, dynamic projection, and polarization multiplexing functionalities.

Toward Efficient and Complete Line Segment Extraction for Large-Scale Point Clouds via Plane Segmentation and Projection

An efficient method based on plane segmentation and projection is proposed to extract as complete boundary (straight) line segments as possible. To efficiently detect boundary points, 3-D planar point clouds (patches) generated by plane segmentation are converted into 2-D images by graphical projection to avoid point-based nearest neighbors’ searching. To preserve boundary details, the projection resolution for each plane is determined through accurate statistics of average local intervals between points in voxels composing corresponding planar point clouds. To alleviate erroneous line segmentation extraction caused by uneven densities of planar point clouds, improved mathematical morphological operation, whose structural element order is self-adaptive to local point density, is proposed for crack inpainting of projected images. As for extraction of 3-D boundary line segments, the back-projection results of 2-D boundary line segments detected from images are utilized as references for clustering of boundary points, and a 3-D straight line fitting algorithm based on recursive weighted least squares is employed to reduce the effect of boundary noise. A series of refinement strategies are further presented to control the quality of extracted 3-D line segments. Experimental results demonstrate that the proposed line segment extraction method can provide efficient and fine processing results, as well as automatic processing ability, which satisfies the efficient processing demand for large-scale point clouds.

Compact reconstruction of a Fourier hologram for a 3D object by scaling compensation.

The Fourier holographic projection method is compact and computationally fast. However, since the magnification of the displayed image increases with the diffraction distance, this method cannot be used directly to display multi-plane three-dimensional (3D) scenes. We propose a holographic 3D projection method of Fourier holograms by scaling compensation to offset the magnification during optical reconstruction. To achieve a compact system, the proposed method is also used to reconstruct 3D virtual images with Fourier holograms. Different from traditional Fourier holographic displays, images are reconstructed behind a spatial light modulator (SLM) so that the observation position can be placed close to the SLM. The effectiveness of the method and the flexibility of combining it with other methods are confirmed by simulations and experiments. Therefore, our method could have potential applications in the augmented reality (AR) and virtual reality (VR) fields.

Quantum 3D FFT in Tomography

The Radon transform constitutes the conventional tool for tomosynthesis, i.e., the composition of cross-sections of an object from its projections. It is actually a version of the Fourier Transform, which is accompanied by the appropriate digital high pass filters for correct distribution of energy among the reconstructed frequency components. The Radon transform and its inverse are employed in their 2D and 3D versions, respectively, and the whole procedure is verified by the a priori known cross-sections to be reconstructed (known fandom). Usually, 3D medical image cubes, which are to be reconstructed, require powerful computational tools since the 2D projections are of high-resolution containing millions of pixels. Although the 3D FFT is very fast, the large number of projections will result in a 3D spectrum of very large dimensions. Inverting this spectrum with the inverse 3D FFT is extremely time consuming. In this work, the implementation of the 2D Radon transform using the 2D Quantum Fourier Transform is analytically presented. Simultaneously, its inverse version is realized by means of the Quantum inverse 3D FFT. For this purpose, a review of the necessary quantum computational units is presented for the implementation of the quantum 3D FFT and simultaneously simple examples of tomosynthesis are given by means of the quantum version of the 2D Radon transform and its inverse 3D counterpart. The whole procedure of the quantum tomosynthesis is analytically described.

Validation of a stereological method for estimating particle size and density from 2D projections with high accuracy.

Stereological methods for estimating the 3D particle size and density from 2D projections are essential to many research fields. These methods are, however, prone to errors arising from undetected particle profiles due to sectioning and limited resolution, known as 'lost caps'. A potential solution developed by Keiding, Jensen, and Ranek in 1972, which we refer to as the Keiding model, accounts for lost caps by quantifying the smallest detectable profile in terms of its limiting 'cap angle' (ϕ), a size-independent measure of a particle's distance from the section surface. However, this simple solution has not been widely adopted nor tested. Rather, model-independent design-based stereological methods, which do not explicitly account for lost caps, have come to the fore. Here, we provide the first experimental validation of the Keiding model by comparing the size and density of particles estimated from 2D projections with direct measurement from 3D EM reconstructions of the same tissue. We applied the Keiding model to estimate the size and density of somata, nuclei and vesicles in the cerebellum of mice and rats, where high packing density can be problematic for design-based methods. Our analysis reveals a Gaussian distribution for ϕ rather than a single value. Nevertheless, curve fits of the Keiding model to the 2D diameter distribution accurately estimate the mean ϕ and 3D diameter distribution. While systematic testing using simulations revealed an upper limit to determining ϕ, our analysis shows that estimated ϕ can be used to determine the 3D particle density from the 2D density under a wide range of conditions, and this method is potentially more accurate than minimum-size-based lost-cap corrections and disector methods. Our results show the Keiding model provides an efficient means of accurately estimating the size and density of particles from 2D projections even under conditions of a high density.

Human umbilical cord blood cells suffer major modification by fixatives and anticoagulants.

Introduction: Developing techniques for the tagless isolation of homogeneous cell populations in physiological-like conditions is of great interest in medical research. A particular case is Gravitational Field-Flow Fractionation (GrFFF), which can be run avoiding cell fixation, and that was already used to separate viable cells. Cell dimensions have a key role in this process. However, their dimensions under physiological-like conditions are not easily known since the most diffused measurement techniques are performed on fixed cells, and the fixation used to preserve tissues can alter the cell size. This work aims to obtain and compare cell size data under physiological-like conditions and in the presence of a fixative. Methods: We developed a new protocol that allows the analysis of blood cells in different conditions. Then, we applied it to obtain a dataset of human cord blood cell dimensions from 32 subjects, comparing two tubes with anticoagulants (EDTA and Citrate) and two tubes with different preservatives (CellRescue and CellSave). We analyzed a total of 2071 cells by using confocal microscopy via bio-imaging to assess dimensions (cellular and nuclear) and morphology. Results: Cell diameter measured does not differ when using the different anticoagulants, except for the increase reported for monocyte in the presence of citrate. Instead, cell dimensions differ when comparing anticoagulants and cell preservative tubes, with a few exceptions. Cells characterized by high cytoplasm content show a reduction in their size, while morphology appears always preserved. In a subgroup of cells, 3D reconstruction was performed. Cell and nucleus volumes were estimated using different methods (specific 3D tool or reconstruction from 2D projection). Discussion: We found that some cell types benefit from a complete 3D analysis because they contain non-spherical structures (mainly for cells characterized by poly-lobated nucleus). Overall, we showed the effect of the preservatives mixture on cell dimensions. Such an effect must be considered when dealing with problems highly dependent on cell size, such as GrFFF. Additionally, such information is crucial in computational models increasingly being employed to simulate biological events.

Motion estimation based on projective information disentanglement for 3D reconstruction of rotational coronary angiography

The 2D projection space-based motion compensation reconstruction (2D-MCR) is a kind of representative method for 3D reconstruction of rotational coronary angiography owing to its high efficiency. However, due to the lack of accurate motion estimation of the overlapping projection pixels, existing 2D-MCR methods may still have a certain level of under-sampling artifacts or lose accuracy for cases with strong cardiac motion. To overcome this, in this study, we proposed a motion estimation approach based on projective information disentanglement (PID-ME) for 3D reconstruction of rotational coronary angiography. The reconstruction method adopts the framework of 2D-MCR, which is referred to as 2D-PID-MCR. The PID-ME consists of two parts: generation of the reference projection sequence based on the fast simplified distance driven projector (FSDDP) algorithm, motion estimation and correction based on the projective average minimal distance measure (PAMD) model. The FSDDP algorithm generates the reference projection sequence faster and accelerates the whole reconstruction greatly. The PAMD model can disentangle the projection information effectively and estimate the motion of both overlapping and non-overlapping projection pixels accurately. The main contribution of this study is the construction of 2D-PID-MCR to overcome the inherent limitations of the existing 2D-MCR method. Simulated and clinical experiments show that the PID-ME, consisting of FSDDP and PAMD, can estimate the motion of the projection sequence data accurately and efficiently. Our 2D-PID-MCR method outperforms the state-of-the-art approaches in terms of accuracy and real-time performance.

Development of an automated reconfigurable robotic airplane fuselage panel final assembly system using state-of-the-art automation technologies

ABSTRACT Airspace companies regularly incorporate state-of-the-art automation technologies into their aircraft assembly systems to reduce lead times and manufacturing costs and improve product quality in their assembly plants. Rapid advances in assembly automation, robotics, material handling, measurement in the assembly processes, and systematic design methodologies require constant consideration of new applications and technologies in assembly systems’ design studies for airplane structures such as fuselage panels. Such a design study is performed in this study to enable the formation of an automated, reconfigurable and robotic fuselage panel final assembly system. The authors’ extensive review of the literature and catalogs reveals that stringer positioning robots, 3D projection devices for fastener position controls on the panels, reconfigurable fixtures for holding the panels, mobile refill friction stir spot joining robots to assemble clips to frames, robotic measurement systems, and modular crane for material handling can be used as state-of-the-art automation technologies in an automated and reconfigurable fuselage panel final assembly system. The proposed automated, reconfigurable, and robotic fuselage panel final assembly system provides an increase in its performance of adaptation level to the changes in the panel types, customers’ order quantities, and suppliers’ and customers’ delivery dates.

Sub-Jovian desert of exoplanets at its boundaries

Context. The lack of sub-Jovian planets on orbits of Porb &lt; 3 days is a puzzling aspect of galaxy formation with regard to the distribu-tion of exoplanets whose origins are currently unresolved. Aims. The possible explanations behind the formation of the sub-Jovian or Neptunian desert include several scenarios that can lead to different shapes for the boundary, predicting various dependencies between the position of the boundary and the stellar parameters. Methods. We explored the exoplanet distribution in various 2D and 3D projections, revealing the stellar-dependent substructures in the Porb–MP and the Porb–RP parameter plane. Results. We demonstrate that the upper boundary includes a range of planets, namely, inflated hot Jupiters and normal hot Jupiters, in the two parameter planes, respectively. We confirm the dependence of the boundary on several stellar parameters and, based on a fuzzy clustering analysis, we provide quantitative formulae for the dependencies in groups of smaller and larger planets. The overall period-radius distribution shows chemical substructures as well, with the boundary being dependent on volatiles and alpha-elements, alongside marginal (to none) dependence found for refractory elements. Conclusions. These findings confirm multiple plausible causes for the formation of the desert, particularly preferring those scenarios related to the irradiation-driven loss of the atmospheres of moderately massive planets as the predominant process in shaping planetary distributions.

High pressure mediated physical properties of Hf2AB (A = Pb, Bi) via DFT calculations

Using density functional theory (DFT), the structural, mechanical, electronic, thermal, and optical properties of Hf2AB (A = Pb, Bi) borides were studied, considering the pressure effect up to 50 GPa. The lattice constants were found to be decreased with increasing pressure wherein the lattice constants at 0 GPa agree well with the reported values. The stability (mechanical and dynamical) of the titled compounds at different pressures was checked. The mechanical behavior was disclosed considering the bulk modulus, shear modulus, Youngs modulus, Pugh ratio, Poissons ratio, and hardness parameter at different pressures. Pugh and Poisson ratios were used to assess the brittleness and ductility of the titled borides. The anisotropic nature of mechanical properties was studied by calculating different indices and plotting 2D and 3D projections of the elastic moduli. The electronic properties were revealed by calculating the band structure, density of states, and charge density mapping at different pressures, wherein the anisotropic nature of the electronic conductivity was noted. We studied the Debye temperature, minimum thermal conductivity, Gruneisen parameter, and melting temperature of the titled borides at different pressures; the results revealed the improvement of the mentioned properties with rising pressure. The important optical constants to disclose the possible relevance in application purposes were investigated; a little pressure effect was noted. The thermal properties suggest that the titled borides could be used as thermal barrier coating (TBC) materials while the reflectivity spectra revealed their suitability to be used as cover materials for protection from solar heating.

D$^\text{2}$UF: Deep Coded Aperture Design and Unrolling Algorithm for Compressive Spectral Image Fusion

Compressive spectral imaging (CSI) has attracted significant attention since it employs synthetic apertures to codify spatial and spectral information, sensing only 2D projections of the 3D spectral image. However, these optical architectures suffer from a trade-off between the spatial and spectral resolution of the reconstructed image due to technology limitations. To overcome this issue, compressive spectral image fusion (CSIF) employs the projected measurements of two CSI architectures with different resolutions to estimate a high-spatial high-spectral resolution. This work presents the fusion of the compressive measurements of a low-spatial high-spectral resolution coded aperture snapshot spectral imager (CASSI) architecture and a high-spatial low-spectral resolution multispectral color filter array (MCFA) system. Unlike previous CSIF works, this paper proposes joint optimization of the sensing architectures and a reconstruction network in an end-to-end (E2E) manner. The trainable optical parameters are the coded aperture (CA) in the CASSI and the colored coded aperture in the MCFA system, employing a sigmoid activation function and regularization function to encourage binary values on the trainable variables for an implementation purpose. Additionally, an unrolling-based network inspired by the alternating direction method of multipliers (ADMM) optimization is formulated to address the reconstruction step and the acquisition systems design jointly. Finally, a spatial-spectral inspired loss function is employed at the end of each unrolling layer to increase the convergence of the unrolling network. The proposed method outperforms previous CSIF methods, and experimental results validate the method with real measurements.

A novel histological occlusion classification for coiled aneurysms based on multiphoton microscopy.

Intracranial aneurysm (IA) coiling remains the most commonly used endovascular approach for ruptured and unruptured IA, and recanalization is a common drawback that impairs treatment success. Angiographic occlusion and aneurysm healing are not synonymous, and histological evaluation of embolized aneurysms remains a challenge. We propose here an experimental study of coil embolization in animal models by multiphoton microscopy (MPM) in comparison with conventional histological staining. The purpose of his work is to analyze coil healing process using histological sections of aneurysms. Based on a rabbit elastase model, 27 aneurysms were fixed, embedded in resin, and cut in thin histological sections 1 month after coils implantation and after angiographic control. Hematoxylin and eosin (H&S) staining were realized. Non-stained adjacent slices were imaged for multiphoton excited autofluorescence (AF) and second-harmonic generation (SHG) to construct three-dimensional (3D) projections of sequentially and axially acquired images. The contrast provided by the combination of these two imaging modalities can be used to distinguish five levels of aneurysm healing, based on a combination of thrombus evolution and increased extracellular matrix (ECM) deposit. RDPC:\Users\SHAHUL\RDP6|We have established a novel histological scale from a rabbit elastase aneurysm model after coiling with a classification of five different stages thanks to nonlinear microscopy. This classification is an actualized tool in order to obtain a more precise evaluation of occlusion device efficacy in the scope of new innovative microscopy for research.

Unravelling 3D Dynamics and Hydrodynamics during Incorporation of Dielectric Particles to an Optical Trapping Site.

Mapping of the spatial and temporal motion of particles inside an optical field is critical for understanding and further improvement of the 3D spatio-temporal control over their optical trapping dynamics. However, it is not trivial to capture the 3D motion, and most imaging systems only capture a 2D projection of the 3D motion, in which the information about the axial movement is not directly available. In this work, we resolve the 3D incorporation trajectories of 200 nm fluorescent polystyrene particles in an optical trapping site under different optical experimental conditions using a recently developed widefield multiplane microscope (imaging volume of 50 × 50 × 4 μm3). The particles are gathered at the focus following some preferential 3D channels that show a shallow cone distribution. We demonstrate that the radial and the axial flow speed components depend on the axial distance from the focus, which is directly related to the scattering/gradient optical forces. While particle velocities and trajectories are mainly determined by the trapping laser profile, they cannot be completely explained without considering collective effects resulting from hydrodynamic forces.

Cerebral white matter lesions and regional blood flow are associated with reduced cognitive function in early-stage cognitive impairment.

Differences in the extent of cerebral white matter lesions (WML) and regional cerebral blood flow (rCBF) in early-stage cognitive impairment (ESCI) contribute to the prognosis of cognitive decline; however, it is unclear precisely how WML and rCBF affect cognitive decline in ESCI. We examined the association between WML, rCBF, and cognitive impairment in the ESCI, using path analysis to clarify how these variables affect each other. Eighty-three patients who consulted our memory clinic regarding memory loss were included in this study based on the Clinical Dementia Rating. Participants underwent the Mini-Mental State Examination (MMSE), brain magnetic resonance imaging (MRI) for voxel-based morphometry analysis, and brain perfusion single-photon emission computed tomography (SPECT) for rCBF evaluation in cortical regions, using 3D stereotactic surface projection (3D-SSP) analysis. Path analysis was performed on the MRI voxel-based morphometry and SPECT 3D-SSP data, showing a significant correlation between both and MMSE scores. In the most suitable model (GFI = 0.957), correlations were observed between lateral ventricular (LV-V) and periventricular WML (PvWML-V) volumes [standardized coefficient (SC) = 0.326, p = 0.005], LV-V and rCBF of the anterior cingulate gyrus (ACG-rCBF; SC = 0.395, p < 0.0001), and ACG-rCBF and PvWML-V (SC = 0.231, p = 0.041). Furthermore, a direct relationship between PvWML-V and MMSE scores was identified (SC = -0.238, p = 0.026). Significant interrelationships were observed among the LV-V, PvWML-V, and ACG-rCBF that directly affected the MMSE score in the ESCI. The mechanisms behind these interactions and the impact of PvWML-V on cognitive function require further investigation.