Sharp Edges Research Articles

Hot extrusion of SiCp/Al-Cu composites: optimizing mechanical properties through microstructural control

The solid-state processing and utilization of light-metal-based composites align with green policies by reducing the weight of components and employing lower processing temperatures compared to traditional metallurgical methods. This study explores the incorporation of SiC particles at concentrations of 5 and 10 wt.% into an Al4Cu matrix through powder mixing, compaction at 235 MPa, hot extrusion, and sintering at 600 °C in a nitrogen atmosphere. The resulting microstructure, hardness, compressive strength, and flexural strength of the composites were evaluated. During extrusion, the composite underwent plastic deformation, leading to cracking and fragmentation of the SiC particles within the matrix. Therefore, evenly distributed reinforcing particles with a diameter much smaller than the originally introduced ceramic particles were observed. Recrystallization also occurred, with Al2Cu precipitates forming on grain boundaries and nanosized Al2O3 oxides observed in porous areas and at matrix-reinforcement interphase boundaries. The composite containing 5 wt.% SiC exhibited the highest compressive strength of 305 MPa, while the composite with 10 wt.% SiC achieved the highest flexural strength of 889 MPa. However, non-deformable SiC particles crack before reaching maximum strength due to stress concentration at their sharp edges, initiating microcracks in the matrix. Microstructural analysis further revealed that SiC particles tend to crack during hot extrusion, reducing their effectiveness in stress transfer. The hardness remained constant at 78 HV1, irrespective of SiC content. These findings demonstrate that the addition of SiC particles significantly enhances the mechanical properties of Al4Cu composites, making them promising materials for lightweight and high-strength applications.

Assessment of multi-modal magnetic resonance imaging for glioma based on a deep learning reconstruction approach with the denoising method.

Deep learning reconstruction (DLR) with denoising has been reported as potentially improving the image quality of magnetic resonance imaging (MRI). Multi-modal MRI is a critical non-invasive method for tumor detection, surgery planning, and prognosis assessment; however, the DLR on multi-modal glioma imaging has not been assessed. To assess multi-modal MRI for glioma based on the DLR method. We assessed multi-modal images of 107 glioma patients (49 preoperative and 58 postoperative). All the images were reconstructed with both DLR and conventional reconstruction methods, encompassing T1-weighted (T1W), contrast-enhanced T1W (CE-T1), T2-weighted (T2W), and T2 fluid-attenuated inversion recovery (T2-FLAIR). The image quality was evaluated using signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and edge sharpness. Visual assessment and diagnostic assessment were performed blindly by neuroradiologists. In contrast with conventionally reconstructed images, (residual) tumor SNR for all modalities and tumor to white/gray matter CNR from DLR images were higher in T1W, T2W, and T2-FLAIR sequences. The visual assessment of DLR images demonstrated the superior visualization of tumor in T2W, edema in T2-FLAIR, enhanced tumor and necrosis part in CE-T1, and fewer artifacts in all modalities. Improved diagnostic efficiency and confidence were observed for preoperative cases with DLR images. DLR of multi-modal MRI reconstruction prototype for glioma has demonstrated significant improvements in image quality. Moreover, it increased diagnostic efficiency and confidence of glioma.

A thousand converging paths to self-observation and self-discovery: science, spirituality and philosophical practice

This article aims to connect dots from different schools of thought and argues for the importance of an interdisciplinary approach to any subject matter and the immense potential the virtually endless openings thus created can represent for philosophical counseling. It brings arguments on the importance of understanding from linguistic nuances, in any strict systematic discipline that builds and organizes knowledge in the form of testable hypotheses and predictions about the world, to various symbolic systems of spiritual practices. It emphasizes the formal logic of mathematics – which comes from the ancient Greek notion máthēma (μάθημα), meaning "that which is learned", "what one gets to know", hence also "study" and "science" – in an attempt to simplify complexities but also the importance, for one’s philosophical journey to self-harmonization with existence, of a large number of alternative types and forms of reconstruction of reality devised by mankind. By employing pure or applied mathematics thinking patterns – if addressed to scientifically-minded interlocutors –, philosophy qua practice can build bridges between disciplines by cross-translating specific glossaries, focusing on referential points, and emancipative essences, and smoothing sharp edges - in the search for a broader, common denominator, and collective viewpoint. For instance, for clients with advanced scientific backgrounds and high expectations, it can start the dialogic reflections from philosophy’s own sophisticated toolset able explain the Doppler shift of psychohistory, by de-noising - in midair - the different observable perspectives, in the multipolar, prone to gridlock, umwelt of humanity. For other clients, less scientific yet read and inclined towards objective realism, philosophical counseling can still start their transformative journey from anchoring their worldviews in the fact that the laws of physics are here to stay, yet suggesting the adoption of the observer effect through which, in our commuting with nature, neutrality can have a harmonizing effect on the viability of what constitutes the "is", starting from the individual "know thyself", continuing with the containing physical, ideological, spiritual frameworks to identify inflection points and prepare next adjacencies for evolution in the collective reality. For many other potential philosophically inclined clients, other spiritual practices such as various religions or meditation are crucial coordinates of their lives and around which philosophical counselors can revolve the dialogue. Yet other people are inclined to philosophize through favorite insightful song lyrics and melodies. Philosophical counseling can help to leave no one behind in terms of finding meaning, decision grounding, and, or at least, peace. Whatever that might mean, on micro and macro levels. Building a philosophical journey "ark" needs a blueprint, and requires a list of "animals", a pair of each kind - the "good" and "bad" sides, hand in hand, of any identifiable entity - before it sets sail towards the unknown, the open sea. In the narrow neck of the present, in the sand clock between past and future every client who seeks assistance feels at the crossroads of the reflected side of "where do I/We come from" and the "where am/are I/We going! " regardless if "we" - as a collective - understand or not "what are We".

Naming the stars.

In this poem, the author is a hospitalized patient who had been struck by a car while she was walking on a moonless night. In the emergency room, scalpels, scissors, and stars aligned, assembled by her frightened brain. Name your fears and you banish them. The author never knew the stars had names, nor that sharp edges could soften, could suture as deftly as sever, could stitch a path out of her darkness, and light her from broken to whole. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

ANSELM’S ONTOLOGICAL ARGUMENT AND GRADES OF BEING

AbstractAnselm described god as “something than which nothing greater can be thought” [1, p. 93], and Descartes viewed him as “a supreme being” [7, p. 122]. I first capture those characterizations formally in a simple language for monadic predicate logic. Next, I construct a model class inspired by Stoic and medieval doctrines of grades of being [8, 20]. Third, I prove the models sufficient for recovering, as internal mathematics, the famous ontological argument of Anselm, and show that argument to be, on this formalization, valid. Fourth, I extend the models to incorporate a modality fit for proving that any item than which necessarily no greater can be thought is also necessarily real. Lastly, with the present approach, I blunt the sharp edges of notable objections to ontological arguments by Gaunilo and by Grant. A trigger warning: every page of this writing flouts the old saw “Existence is not a predicate” and flagrantly.

Reversed self-steepening in Si3N4-organic hybrid slot waveguides with engineered nonlinearity

Abstract Dispersion of nonlinearity greatly influences both temporal and spectral evolutions for ultrashort pulses, although difficult to be tailored in a wide spectral range. Here, we show the hardly observable reversed self-steepening in an on-chip Si3N4-organic hybrid slot waveguide with sophisticated dispersion and an increased nonlinear coefficient with wavelength. An octave-spanning supercontinuum with significant red-shift spectral broadening and a rectangle-shaped pulse waveform with a sharp rising edge of 13 fs can be generated. We study the robustness of reversed self-steepening under different operating conditions and reveal its nonlinear dynamics. This deepens the understanding on the dispersion of nonlinearity and helps develop novel nonlinearity-engineered devices for on-chip optical shock formation, pulse shaping, and signal processing in the future.

Deep Learning-Enhanced Accelerated 2D TSE and 3D Superresolution Dixon TSE for Rapid Comprehensive Knee Joint Assessment.

The aim of this study was to evaluate the use of a multicontrast deep learning (DL)-reconstructed 4-fold accelerated 2-dimensional (2D) turbo spin echo (TSE) protocol and the feasibility of 3-dimensional (3D) superresolution reconstruction (SRR) of DL-enhanced 6-fold accelerated 2D Dixon TSE magnetic resonance imaging (MRI) for comprehensive knee joint assessment, by comparing image quality and diagnostic performance with a conventional 2-fold accelerated 2D TSE knee MRI protocol. This prospective, ethics-approved study included 19 symptomatic adult subjects who underwent knee MRI on a clinical 3 T scanner. Every subject was scanned with 3 DL-enhanced acquisition protocols in a single session: a clinical standard 2-fold in-plane parallel imaging (PI) accelerated 2D TSE-based protocol (5 sequences, 11 minutes 23 seconds) that served as a reference, a DL-reconstructed 4-fold accelerated 2D TSE protocol combining 2-fold PI and 2-fold simultaneous multislice acceleration (5 sequences, 6 minutes 24 seconds), and a 3D SRR protocol based on DL-enhanced 6-fold accelerated (ie, 3-fold PI and 2-fold simultaneous multislice) 2D Dixon TSE MRI (6 anisotropic 2D Dixon TSE acquisitions rotated around the phase-encoding axis, 6 minutes 24 seconds). This resulted in a total of 228 knee MRI scans comprising 21,204 images. Three readers evaluated all pseudonymized and randomized images in terms of image quality using a 5-point Likert scale. Two of the readers (musculoskeletal radiologists) additionally evaluated anatomical visibility and diagnostic confidence to assess normal and pathological knee structures with a 5-point Likert scale. They recorded the presence and location of internal knee derangements, including cartilage defects, meniscal tears, tears of ligaments, tendons and muscles, and bone injuries. The statistical analysis included nonparametric Friedman tests, and interreader and intrareader agreement assessment using the weighted Fleiss-Cohen kappa (κ) statistic. P values of less than 0.05 were considered statistically significant. The evaluated DL-enhanced 4-fold accelerated 2D TSE protocol provided very similar image quality and anatomical visibility to the standard 2D TSE protocol, whereas the 3D SRR Dixon TSE protocol scored less in terms of overall image quality due to reduced edge sharpness and the presence of artifacts (P < 0.001). Subjective signal-to-noise ratio, contrast resolution, fluid brightness, and fat suppression were good to excellent for all protocols. For 1 reader, the Dixon method of the 3D SRR protocol provided significantly better fat suppression than the spectral fat saturation applied in the standard 2D TSE protocol (P < 0.05). The visualization of knee structures with 3D SRR Dixon TSE was very similar to the standard protocol, except for cartilage, tendons, and bone, which were affected by the presence of reconstruction and aliasing artifacts (P < 0.001). The diagnostic confidence of both readers was high for all protocols and all knee structures, except for cartilage and tendons. The standard 2D TSE protocol showed a significantly higher diagnostic confidence for assessing tendons than 3D SRR Dixon TSE MRI (P < 0.01). The interreader and intrareader agreement for the assessment of internal knee derangements using any of the 3 protocols was substantial to almost perfect (κ = 0.67-1.00). For cartilage, the interreader agreement was substantial for DL-enhanced accelerated 2D TSE (κ = 0.79) and almost perfect for standard 2D TSE (κ = 0.98) and 3D SRR Dixon TSE (κ = 0.87). For menisci, the interreader agreement was substantial for 3D SRR Dixon TSE (κ = 0.70-0.80) and substantial to almost perfect for standard 2D TSE (κ = 0.80-0.99) and DL-enhanced 2D TSE (κ = 0.87-1.00). Moreover, the total acquisition time was reduced by 44% when using the DL-enhanced accelerated 2D TSE or 3D SRR Dixon TSE protocol instead of the conventional 2D TSE protocol. The presented DL-enhanced 4-fold accelerated 2D TSE protocol provides image quality and diagnostic performance similar to the standard 2D protocol. Moreover, the 3D SRR of DL-enhanced 6-fold accelerated 2D Dixon TSE MRI is feasible for multicontrast 3D knee MRI as its diagnostic performance is comparable to standard 2-fold accelerated 2D knee MRI. However, reconstruction and aliasing artifacts need to be further addressed to guarantee a more reliable visualization and assessment of cartilage, tendons, and bone. Both the 2D and 3D SRR DL-enhanced protocols enable a 44% faster examination compared with conventional 2-fold accelerated routine 2D TSE knee MRI and thus open new paths for more efficient clinical 2D and 3D knee MRI.

Reduced Persistent Photoconductivity in Successive Ionic Layer Adsorption and Reaction‐Deposited ZnO:Sn Thin Films

Device‐quality Sn‐doped ZnO thin films are obtained from a simple and cost‐effective successive ionic layer adsorption and reaction method with doping concentrations of 1, 3, 5, and 7 mol%. The influence of doping on the structural, morphological, and optoelectronic properties is studied. All the samples show a hexagonal wurtzite structure with planes that reorient themselves upon doping. Morphological studies reveal sharp cone‐like structures branching out to become florets upon doping, resulting in a higher surface‐to‐volume ratio that is reflected in the photoresponse characteristics. The optical properties show a sharp absorbance edge, in the near‐UV region, for all the samples. The calculated bandgap is in the range of 3.19–3.23 eV. Photoluminescence spectra are recorded to analyze the defect states in the samples, and the native defects of ZnO are found. A remarkable increase in current is observed upon illumination indicating significant photoresponse. ZnO tends to show persistent photoconductivity wherein there is delayed decay in the photocurrent. This phenomenon is reduced significantly herein by doping with Sn atoms. The spectral response study confirms that the devices are suitable for visible‐blind, near‐UV detection.

Performance enhancement of a semi-active flapping foil energy harvester via airfoil with modified trailing edge and jet flap

This paper aims to numerically study effectiveness of the use of a suitable combination of an airfoil with modified trailing edge and jet flap in enhancing the energy harvesting performance of a semi-active flapping foil. The configuration of the proposed airfoil is created by referring to the method of generating a blunt trailing edge airfoil. The most promising airfoil profile is obtained by only thickening the rear part of the original airfoil to reach a thickness of 2% chord, which can apparently promote the energy capturing capability of a semi-active flapping foil when compared with its conventional counterpart with a sharp trailing edge airfoil. Furthermore, a jet flap, an active flow control technique, is then applied on the aft portion of the modified airfoil and the effectiveness of this combination is assessed by a comparison with that of the passive flow control device, Gurney flap. The present findings suggest that this combination can be much more effective than a Gurney flap in significantly increasing the energy harvesting efficiency of the semi-active flapping foil over a wide range of operating conditions, and also has the advantage of structural integrity, which make it more suitable for harsh environment applications.

Thermal, chemical and mechanical characterization of Azadirachta indica tree gum

This study focuses on the comprehensive thermal, chemical, and mechanical characterization of neem gum, a natural, colorless, tasteless polysaccharide obtained from Azadirachta indica tree’s trunk. The collection process of gum involves manual extraction from crude neem tree exudates, followed by thorough cleaning and homogenization with water. A portion of the resulting gum is then filtered, allowed to thicken, and naturally dried for subsequent mechanical testing. Various analytical techniques, such as thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) to determine the thermal properties, Fourier transform infrared spectrometry (FTIR) to find the functional groups, scanning electron microscopy (SEM), and micro-X-ray fluorescence analysis (µ-XRF) to decide the elemental composition, microhardness, tensile, flexural, and compression tests to determine the mechanical properties, are employed in this study. The thermal and mechanical properties of neem gum have been relatively unexplored, and this highlights the novelty and importance of this research. The results are analyzed and compared with other natural tree gums. The pH of 5.07 shows that the gum is slightly acidic in nature, and the peaks obtained from thermal analysis demonstrate that it doesn’t have a melting point. The microhardness value, tensile strength, flexural strength, and compressive strength of neem gum are 238.64 MPa, 1.0155 MPa, 1.899 MPa, and 1.1023 MPa, respectively. This research provides valuable insights into the diverse characteristics and potential applications of neem gum in various fields. It is being used in the pharmaceutical industry. It can also be used as a cap for cutting tools, such as drill bits, after manufacturing, during transportation to protect their sharp edges from damage.

The sharp edge of immunosuppressive treatments: infections.

Different side effects, including infections, are encountered in patients receiving anticytokines used for the treatment of severe coronavirus disease 2019 (COVID-19). The aim of this study was to evaluate the infections and the effects of these infections that develop in this patient group. This study included 208 patients who were followed-up with the diagnosis of severe COVID-19 in two different hospitals. Patient data were obtained retrospectively from the hospital information system. Of the 208 patients included, 54 were in the anakinra group, and 154 were in the tocilizumab group. Of these patients, 73 (35.1%) developed infection, 160 (76.9%) were admitted to the intensive care unit (ICU), and the 30-day mortality rate was 46.6%. The ICU admission, 30-day mortality, and infection rates were higher in the anakinra group, but it was not statistically significant (p = 0.137, p = 0.127, and p = 0.132, respectively), while pneumonia and bloodstream infection (BSI) rates were higher (p = 0.043 and p = 0.010 respectively). The 30-day mortality rate was significantly higher in patients who developed infection, especially in the tocilizumab group (p < 0.001 and p = 0.001). The independent risk factors affecting the development of infection were evaluated via regression analysis, in which it was found that age, sex, and the type of immunosuppressive treatment had no significant effect, while ICU admission increased the risk of infection by 32.8 times (95% CI: 4.4-245.8) and each day of hospitalization slightly increased the risk of infection by 1.06 times (95% CI: 1.03-1.09). Infection rates were higher in the anakinra group, especially the pneumonia and BSI rates were higher than in the tocilizumab group. The 30-day mortality rates were higher in patients who had an infection, especially in the tocilizumab group. This is one of the rare studies that evaluated infections developing in patients treated with anakinra and tocilizumab together.

An experimental investigation on copper square electrode wear in electric discharge machining of Hastelloy B2

Hastelloy B2 is a high-performance nickel-molybdenum alloy and has been used in micro reactor, pump, pipe, and corrosion-resistant equipment. Square holes are required in the above application components. Although square holes are easily produced by spending more electrodes wear in Electrical Discharge Machining (EDM). Moreover, the square hole with small electrode wear achieved is a challenging task in thermal machining. Hence, in this work, the effects of EDM process parameters on electrode taper angle, electrode radius, electrode wear length and cutting time of Hastelloy B2 are studied. Taguchi based VišekriterijumskoKompromisnoRangiranje (VIKOR) method is used to find the optimum process parameters and compared with Taguchi based Grey Relational Analysis (GRA) method for validation. The results showed that current and pulse duration greatly affects the electrode wear out surface and edges. The square electrodes with sharp edges and surfaces are fully transformed into hemispherical shapes at electrode ends due to an unstable spark with diffusion of heat. Also, the VIKOR method provides an alternative multi-criteria optimization method that enhances the process performance over the grey relational analysis due to comparability, uniqueness, assessment and prediction.

Truncation effects on circular EHL contact film thickness

Predictions of film thickness in elastohydrodynamic lubricated (EHL) contacts generally rely on the assumption of a semi-infinite equivalent solid to calculate elastic deformations. However, this assumption often fails when the contact is near an edge of one of the solids. This paper explores the impact of a solid edge being close to or within a theoretical EHL contact area on film thickness. We specifically highlight the advantages of a sharp edge over a chamfer, and the non-monotonous effect of the fillet radius on the minimum film thickness. Semi-analytical equations are developed to determine the maximum and minimum lubricant film thickness in a truncated contact and compare numerical results with experimental data in cases involving a chamfer.

Comparison of super-resolution deep learning models for flow imaging

The primary goal of this study is to introduce deep learning (DL) methods as a cost-effective alternative to the computationally intensive Direct Numerical Simulation (DNS) simulations. We show that one can obtain a parametric field from a low-resolution input and map it to a fine grid output, significantly reducing the computational burden. We assess five super-resolution models for up-scaling low-resolution flow data into fine-grid numerical simulations’ output for accuracy and efficiency. The proposed architectures employ convolutional neural networks interconnected in encoder/decoder branches. We investigate these models using turbulent velocity fields inside a suddenly expanded channel characterized by complex features, including turbulence, instabilities, asymmetries, separation, and reattachment. Our results reveal that an encoder/decoder model with residual connections delivers the fastest results, a U-Net-based model with skip connections excels at producing sharper edges in regions prone to blurring, while deeper models incorporating maximum and average pooling layers show superior performance in reconstructing velocity profiles. These findings significantly contribute to our understanding of the potential of deep learning in fluid mechanics. The models presented in this study are trained and validated on standard computer hardware and can be easily adapted to other problems. The findings are promising for discovering and analyzing flow physics, highlighting the potential for DL techniques to improve the accuracy of the available fluid mechanics computational tools.

Numerical study on noise reduction of ground-effect wing with serrated trailing edge

This study proposes a passive bionic noise reduction strategy using serrated trailing edge (TE) designs to be applied to the aero-train's ground-effect wing. The aim is to mitigate TE noise by suppressing the tail vortex under high-speed and near-wall conditions. Three different serrated TE designs were numerically investigated via large eddy simulation, combined with Möhring acoustic analogy theory under Ma = 0.3 to reveal their noise reduction effects. The noise reduction mechanism was analyzed from the perspective of the flow characteristics in the TE boundary layer. The results indicate that all serrated TE designs achieve noise reduction, with the TE2 exhibiting superior performance. This outcome is linked to the ability of serrated TE designs to moderate boundary layer airflow separation and backpressure gradients, facilitating smoother transitions and lessening wake vortex intensity, thereby reducing turbulence-induced noise. Designs featuring wider serration gaps and sharper edges further enhance noise attenuation.

Evaluation of Surgical Reconstruction of Old Tendo Achilles Injury by Bosworth Technique

Background: Chronic Achilles tendon rupture in the watershed hypovascular region (zone II) makes end-to-end repair less feasible. Bosworth's technique, involving gastrocnemius-soleus turndown, was studied to determine its efficacy and functional outcome in repairing chronic tendon in zone II. Objective: To evaluate surgical reconstruction of old Tendo Achilles injury by Bosworth technique. Methods: This prospective study was carried out in Dhaka Medical College Hospital (DMCH) form July 2006 to December 2007. 20 cases were selected as non-randomized purposive sampling technique who came to the out patients department of DMCH. All cases were diagnosed as old neglected Tendo Achilles injury and treated by surgical reconstruction by Bosworth technique. Two cases were lost from follow up and discarded from the study. Finally the study was done on 18 patients. Results: The mean age of the patients was 31.7 years and the lowest and highest cases were 17 and 47 years respectively. The male female ratio was 5:1. One-third (33.3%) patients were day labourer, 22.2% service holders, 16.7% house wives and the rest 27.8% students. Two-Third of the patients (67%) had involvement of left Tendo Achilles and the rest (33%) had right Tendo Achilles. Nearly 40% of patients’ injury was caused by the overhanging edge of the toilet Pan, 27.8% by traumatic rupture, 11.1% assaulted by sharp weapon, another 11.1% by sharp edge of a metallic plate, 5.6% accidentally by sharp cutting knife and 5.5% by broken glass. The mediun level of injury was 3.5 cm above from the insertion of Tendo Achilles, while the lowest and highest level were 2.5 and 6 cm. Minimum delay from injury to operation was 6 weeks and maximum 32 weeks. 5 patients (27.8%) gained normal range of ankle movement, 6 patients (33.3%) decreased by 5° of unaffected side, 4 (22.2%) by 10° and 3 (16.7%) by more than 10⁰. Mean power of planter flexion, mean calf width and mean score to stand on tip toe on injured side relative ........

Perception-Driven Soft-Edge Occlusion for Optical See-Through Head-Mounted Displays.

Systems with occlusion capabilities, such as those used in vision augmentation, image processing, and optical see-through head-mounted display (OST-HMD), have gained popularity. Achieving precise (hard-edge) occlusion in these systems is challenging, often requiring complex optical designs and bulky volumes. On the other hand, utilizing a single transparent liquid crystal display (LCD) is a simple approach to create occlusion masks. However, the generated mask will appear defocused (soft-edge) resulting in insufficient blocking or occlusion leakage. In our work, we delve into the perception of soft-edge occlusion by the human visual system and present a preference-based optimal expansion method that minimizes perceived occlusion leakage. In a user study involving 20 participants, we made a noteworthy observation that the human eye perceives a sharper edge blur of the occlusion mask when individuals see through it and gaze at a far distance, in contrast to the camera system's observation. Moreover, our study revealed significant individual differences in the perception of soft-edge masks in human vision when focusing. These differences may lead to varying degrees of demand for mask size among individuals. Our evaluation demonstrates that our method successfully accounts for individual differences and achieves optimal masking effects at arbitrary distances and pupil sizes.

Ferumoxytol-Enhanced 5D Multiphase Steady-State Imaging Using Rotating Cartesian K-Space With Low-Rank Reconstruction for Pediatric Congenital Heart Disease.

The rotating Cartesian k-space multiphase steady-state imaging with contrast (ROCK-MUSIC) pulse sequence enables acquisition of whole-heart, cardiac phase-resolved images in pediatric congenital heart disease (CHD) without reliance on the ventilator gating signal. Multidimensional reconstruction with low rank tensor (LRT) has shown promise for resolving complex cardiorespiratory motion. To enhance ROCK-MUSIC by resolving cardiorespiratory phases using LRT reconstruction and to enable semi-automatic hyperparameter tuning by developing an image quality scoring model. Retrospective. Thirty patients (45% female, age 2 days to 6.7 years) with CHD. 3-T, four-dimensional (4D) spoiled gradient recalled echo sequence. Eigenvector-based iTerative Self-consistent Parallel Imaging Reconstruction (ESPIRiT) served as the reference comparison for LRT reconstruction. A 4-point Likert scale was used for cardiac and vascular image quality scoring based on cardiac chamber definition, lumen signal uniformity, vascular margin clarity, and motion artifact. Ejection fraction and ventricular volumes were assessed in 16 patients. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and edge sharpness were computed. Intraclass correlation coefficients, Wilcoxon signed-rank test, Bland-Altman. A P-value <0.05 was considered statistically significant. Relative to ESPIRiT, LRT images received significantly higher cardiac (2.81 ± 0.57 vs. 3.19 ± 0.54) and vascular (2.81 ± 0.60 vs. 3.36 ± 0.53) image quality scores. Image quality scoring with semi-automated hyperparameter tuning showed strong correlations (R2 = 0.748) among image quality, SNR, and septal sharpness. Comparison of ejection fraction and volumetry derived from ESPIRiT, and LRT showed no significant systematic difference (P = 0.32). Integration of low-rank reconstruction with ROCK-MUSIC acquisition may be feasible, and semi-automatic hyperparameter tuning could be effective for generating cardiorespiratory resolved images. 2 TECHNICAL EFFICACY: Stage 1.

Structured adaptive boosting trees for detection of multicellular aggregates in fluorescence intravital microscopy

Fluorescence intravital microscopy captures large data sets of dynamic multicellular interactions within various organs such as the lungs, liver, and brain of living subjects. In medical imaging, edge detection is used to accurately identify and delineate important structures and boundaries inside the images. To improve edge sharpness, edge detection frequently requires the inclusion of low-level features. Herein, a machine learning approach is needed to automate the edge detection of multicellular aggregates of distinctly labeled blood cells within the microcirculation. In this work, the Structured Adaptive Boosting Trees algorithm (AdaBoost.S) is proposed as a contribution to overcome some of the edge detection challenges related to medical images. Algorithm design is based on the observation that edges over an image mask often exhibit special structures and are interdependent. Such structures can be predicted using the features extracted from a bigger image patch that covers the image edge mask. The proposed AdaBoost.S is applied to detect multicellular aggregates within blood vessels from the fluorescence lung intravital images of mice exposed to e-cigarette vapor. The predictive capabilities of this approach for detecting platelet-neutrophil aggregates within the lung blood vessels are evaluated against three conventional machine learning algorithms: Random Forest, XGBoost and Decision Tree. AdaBoost.S exhibits a mean recall, F-score, and precision of 0.81, 0.79, and 0.78, respectively. Compared to all three existing algorithms, AdaBoost.S has statistically better performance for recall and F-score. Although AdaBoost.S does not outperform Random Forest in precision, it remains superior to the XGBoost and Decision Tree algorithms. The proposed AdaBoost.S is widely applicable to analysis of other fluorescence intravital microscopy applications including cancer, infection, and cardiovascular disease.

Posterior capsule opacification with two similar-design hydrophobic acrylic intraocular lenses: 3-year results of a randomized controlled trial.

To compare intraindividually the incidence and intensity of posterior capsule opacification (PCO) and Nd:YAG capsulotomy rates between two similar open-loop single-piece hydrophobic acrylic intraocular lenses (IOLs) differing slightly in their particular material, optic surface and sharp posterior edge design over a period of 3 years. Department of Opthalmology, Medical University Vienna. Randomized, prospective, patient- and examiner-masked clinical trial with intraindividual comparison. 100 patients randomly received a Vivinex XY1 IOL in one eye and a Clareon CNA0T0 IOL in the fellow eye. The amount of PCO (score: 0 - 10) was assessed subjectively and objectively with digital retroillumination picturs using automated image analysis software (AQUA). Best-corrected distance visual acuity (CDVA) as well as the presence of glistenings, subjective visual symptoms and Nd:YAG laser capsulotomy rate were noted. 67 of 100 patients were available for the 3-years follow-up examination. The objective PCO score of the Vivinex XY1 IOLs was 1.0 ± 1.0 compared to the PCO score of 1.5 ± 1.2 for the Clareon CNA0T0 IOLs (p < 0.001). 7.5% of patients had a neodymium:yttrium-aluminium-garnet (Nd:YAG) capsulotomy in the Vivinex XY1 eye, and 9.0% had a capsulotomy in the Clareon CNA0T0 eye (p = 1.0). Both hydrophobic acrylic IOLs showed low PCO and YAG rates with a small but significant favor of the Vivinex XY1 IOL compared to the Clareon CNA0T0 IOL. The interaction of various factors such as hydrophobic material, smooth optic surface and sharp posterior optic edge is the major key for PCO prevention.