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The Riemann boundary value problem is a classic problem of complex analysis. It has numerous applications in hydrodynamics and aerodynamics. It is well-studied in the case of rectifiable curves, but results for non-rectifiable curves are relatively new. Here we apply a new approach to this problem on such curves to spirals, including those with infinite length. [ABSTRACT FROM AUTHOR]

Purpose: To compare MR axon radius estimation in human white matter using a multiband spiral sequence combined with field monitoring to the current state‐of‐the‐art echo‐planar imaging (EPI)‐based approach. Methods: A custom multiband spiral sequence was used for diffusion‐weighted imaging at ultra‐high b$$ b $$‐values. Field monitoring and higher order image reconstruction were employed to greatly reduce artifacts in spiral images. Diffusion weighting parameters were chosen to match a state‐of‐the art EPI‐based axon radius mapping protocol. The spiral approach was compared to the EPI approach by comparing the image signal‐to‐noise ratio (SNR) and performing a test–retest study to assess the respective variability and repeatability of axon radius mapping. Effective axon radius estimates were compared over white matter voxels and along the left corticospinal tract. Results: Increased SNR and reduced artifacts in spiral images led to reduced variability in resulting axon radius maps, especially in low‐SNR regions. Test–retest variability was reduced by a factor of approximately 1.5 using the spiral approach. Reduced repeatability due to significant bias was found for some subjects in both spiral and EPI approaches, and attributed to scanner instability, pointing to a previously unknown limitation of the state‐of‐the‐art approach. Conclusion: Combining spiral readouts with field monitoring improved mapping of the effective axon radius compared to the conventional EPI approach. [ABSTRACT FROM AUTHOR]

For every n, we construct two arcs in the plane that intersect at least n times and do not form spirals. The construction is in three stages: we first exhibit two closed curves on the torus that do not form double spirals, then two arcs on the torus that do not form spirals, and finally two arcs in the plane that do not form spirals. The planar arcs provide a counterexample to a proof of Pach and Tóth concerning string graphs. [ABSTRACT FROM AUTHOR]

Introduction: A spiral clavicle plate has been accepted for its superior multidirectional compatibility in the treatment of midshaft clavicle fractures from a biomechanical perspective. However, the influence of the sextant angle (spiral level) definition on biomechanical performance has not been clarified. A conceptual finite element analysis was conducted to identify the advantages and drawbacks of spiral clavicle plates with various sextant angle definitions. Methods: Conventional superior and three different conceptual spiral plates with sextant angle definitions ranging from 45 to 135 degrees were constructed to restore an OTA 15-B1.3 midshaft clavicle fracture model. Three major loading scenarios (cantilever downward bending, axial compression, and axial torsion) were simulated to evaluate the reconstructed structural stiffness and the stress on the clavicle plate and bone screws. Results: The spiral clavicle plate demonstrated greater capability in resisting cantilever downward bending with an increase in sextant angle and showed comparable structural stiffness and implant stress compared to the superior clavicle plate. However, weakened resistance to axial compression load was noted for the spiral clavicle plate, with lowered stiffness and increased stress on the clavicle plate and screws as the spiral level increased. Conclusion: The spiral clavicle plate has been reported to offer multidirectional compatibility for the treatment of midshaft clavicle fractures, as well as geometric advantages in anatomical matching and reduced skin prominence after surgery. The current study supports that remarkable cantilever bending strength can be achieved with this plate. However, users must consider the potential drawback of lowered axial compression resistance in safety considerations. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive study focused on evaluating the strain generated within short concrete columns reinforced with glass-fiber-reinforced polymer (GFRP) bars and spirals under concentric compressive axial loads. This research was motivated by the lack of sufficient data in the literature regarding strain in such columns. Five full-scale RC columns were cast and tested, comprising four strengthened with GFRP reinforcement and one reference column reinforced with steel bars and spirals. This study thoroughly examined the influence of various test parameters, such as the reinforcement type, longitudinal reinforcement ratio, and spacing of spiral reinforcement, on the strain in concrete, GFRP bars, and spirals. The experimental results showed that GFRP–RC columns exhibited similar strain behavior to steel–RC columns up to 85% of their peak loads. The study also highlighted that the bearing capacity of the columns increased by up to 25% with optimized reinforcement ratios and spiral spacing, while the failure mode transitioned from a ductile to a more brittle nature as the reinforcement ratio increased. Additionally, it is preferable to limit the compressive strain in GFRP bars to less than 20% of their ultimate tensile strain and the strain in GFRP spirals to less than 12% of their ultimate strain to ensure the safe and reliable use of these materials in RC columns. This research also considers the prediction of the axial load capacities using established design standards permitting the use of FRP bars in compressive members, namely ACI 440.11-22, CSA-S806-12, and JSCE-97, and underscores their limitations in accurately predicting GFRP–RC columns' failure capacities. This study proposes an equation to enhance the prediction accuracy for GFRP–RC columns, considering the contributions of concrete, spiral confinement, and the axial stiffness of longitudinal GFRP bars. This equation addresses the shortcomings of existing design standards and provides a more accurate assessment of the axial load capacities for GFRP–RC columns. The proposed equation outperformed numerous other equations suggested by various researchers when employed to estimate the strength of 42 columns gathered from the literature. [ABSTRACT FROM AUTHOR]

Many researchers have studied how modifying conventional shear reinforcement into spiral and truss systems improves the behavior of RC beams. However, there is a scarcity of studies investigating the influence of spiral reinforcement, and limited research is available on the flexural capacity of beams utilizing truss reinforcement systems. Additionally, recent designs focused only on the rectangular spiral and rectangular truss systems, underscoring the necessity of incorporating a new design of modifications in the stirrup configurations. These gaps must be addressed to identify the most effective design for achieving the desired flexural capacities. As a result, the present study conducts a simulation and experimentation on RC beams utilizing modified stirrups through the Abaqus software to describe the load-deflection relationship, determine the flexural capacity and ductility, and analyze the failure mode and crack patterns. The present study simulated seventeen finite element models, including one control beam as BN and four various designs that used rectangular spiral (BR-S), rectangular truss system (BT-R), and a new modification, namely vertical X-shaped stirrups (BV-X), and X-shaped truss system (BT-X) with four spacings of 150mm, 125mm, 100mm, and 75mm. The findings reveal that the most effective enhancement in RC beam behavior was observed within the BT-R group, particularly with BT-R 100, which demonstrated a remarkable 6.551% increase in flexural capacity compared to BN. Moreover, stirrup spacing and inclination considerably impact the beam's performance, depending on the various modifications of stirrups in RC beams. Furthermore, uniform failure modes have been observed across all models and specimens, including BN, demonstrating that modified stirrups improve RC beam performance. The present study compared and verified the finite element simulation results through an actual experiment from BN and BT-R 150 models and specimens. [ABSTRACT FROM AUTHOR]

The symbolism of the spiral and the meander is well known from the ornaments on Minoan and Mycenaean artifacts, while the roots of this symbolism can be traced chronologically much deeper than these cultures and have been fixed since the Paleolithic era. This symbolism has always been of interest to researchers, as it is evidence of the archetypal use of these symbols in the process of formation of religious views of Homo sapiens from the Paleolithic era to the present. In the proposed work, possible ways of formation of this symbolism are considered on the basis of the trajectory of the Sun's movement above the horizon line observed by the priests of various cultures and the represented path of the Sun's movement below the horizon line.

Russia enjoys a stable demand for flour products, including those obtained by the dry method of starch and gluten production. This study featured pneumocentrifugal parameters of fine particles in a spiral separator that classified milled grain into fractions, separated the solid phase from air, and identified the high-protein flour fraction in the flow. Pneumatically classified flour was subjected to mathematical modeling and experimental research. The analysis of movement and deposition of particles in the working area covered particle mass, density, air-flow rate, and geometry, as well as their effect on the trajectory of particle movement and deposition. The experiment also involved the effect of air-flow rate and air-mix concentration on the classification efficiency. Particles from various grinding and break systems demonstrated classification modes that differed in soaring rate, size, and density. At an air-flow rate of 6–8 m/s, turn 1 of the spiral separator had the ratio of the internal coil radius to the inner pipe diameter as r1/dpipe = 7.9; it was r1/dpipe = 7 on turn 2 and fell down to r1/dpipe = 6.25 on turn 3; for all subsequent turns, the ratio was r1/dpipe < 5. Under these conditions, the fraction reached 160 µm and included small high-protein flour fractions with a particle size of 17–20 µm. The percentage of product accumulated on turns 1, 2, and 3 was 80, 12, and 8%, respectively. The maximal product separation efficiency of the third drain system was as high as 98% at an input rate of 6 m/s. The maximal separation efficiency for premium flour reached 99.2% at an input rate of 4.2 m/s. The separator proved efficient in classifying wheat grain flour into fractions as it was able to separate high-protein fraction and dispersed particles from the air flow. The separator could be used both as an independent device and as part of a complex technological scheme at the stage of pneumatic separators and unloaders.

Purpose: To investigate spiral‐based imaging including trajectories with undersampling as a fast and robust alternative for phase‐based magnetic resonance electrical properties tomography (MREPT) techniques. Methods: Spiral trajectories with various undersampling ratios were prescribed to acquire images from an experimental phantom and a healthy volunteer at 3T. The non‐Cartesian acquisitions were reconstructed using SPIRiT, and conductivity maps were derived using phase‐based cr‐MREPT. The resulting maps were compared between different sampling trajectories. Additionally, a conductivity map was obtained using a Cartesian balanced SSFP acquisition from the volunteer to comparatively demonstrate the robustness of the proposed method. Results: The phantom and volunteer results illustrate the benefits of the spiral acquisitions. Specifically, undersampled spiral acquisitions display improved robustness against field inhomogeneity artifacts and lowered SD values with shortened readout times. Furthermore, average of conductivity values measured for the cerebrospinal fluid with the spiral acquisitions were 1.703 S/m, indicating a close agreement with the theoretical values of 1.794 S/m. Conclusion: A spiral‐based acquisition framework for conductivity imaging with and without undersampling is presented. Overall, spiral‐based acquisitions improved robustness against field inhomogeneity artifacts, while achieving whole head coverage with multiple averages in less than a minute. [ABSTRACT FROM AUTHOR]

Purpose: Robust implementation of spiral imaging requires efficient deblurring. A deblurring method was previously proposed to separate and deblur water and fat simultaneously, based on image‐space kernel operations. The goal of this work is to improve the performance of the previous deblurring method using kernels with better properties. Methods: Four types of kernels were formed using different models for the region outside the collected k‐space as well as low‐pass preconditioning (LP). The performances of the kernels were tested and compared with both phantom and volunteer data. Data were also synthesized to evaluate the SNR. Results: The proposed "square" kernels are much more compact than the previously used circular kernels. Square kernels have better properties in terms of normalized RMS error, structural similarity index measure, and SNR. The square kernels created by LP demonstrated the best performance of artifact mitigation on phantom data. Conclusions: The sizes of the blurring kernels and thus the computational cost can be reduced by the proposed square kernels instead of the previous circular ones. Using LP may further enhance the performance. [ABSTRACT FROM AUTHOR]

In conventional parabolic trough collectors (PTCs), sunlight is concentrated at the bottom of the absorber tube, resulting in a significant circumferential temperature gradient across the absorber tube, heat loss and thermal deformation, which affects the safety and thermal performance of PTCs. In this study, a new receiver with homogenizer and spiral (RHS) is proposed, achieving the optical and thermal synergy to ameliorate the thermal deformation of the absorber tube and enhance thermal efficiency. A plane structure homogenizer is designed to improve uniformity of the concentrated solar flux of absorber tube through second reflection. In combination with the spiral, it improves the optical-thermal efficiency of the PTC by enhancing heat exchange between the fluid and the backlight side of the absorber tube. The performance of the collector is numerically studied by building a three-dimensional coupled light-thermal-structure model. The results show that the thermal deformation of the RHS is reduced by more than 96% and the optical-thermal efficiency is improved by 1.2%–0.63% compared with conventional receivers (CRs) under the same inlet temperature conditions. The proposed receiver is validated to be effective in reducing thermal deformation and improving optical-thermal efficiency. [ABSTRACT FROM AUTHOR]

The objective of the current study was to develop and evaluate a DEep learning‐based rapid Spiral Image REconstruction (DESIRE) and deep learning (DL)‐based segmentation approach to quantify the left ventricular ejection fraction (LVEF) for high‐resolution spiral real‐time cine imaging, including 2D balanced steady‐state free precession imaging at 1.5 T and gradient echo (GRE) imaging at 1.5 and 3 T. A 3D U‐Net–based image reconstruction network and 2D U‐Net–based image segmentation network were proposed and evaluated. Low‐rank plus sparse (L+S) served as the reference for the image reconstruction network and manual contouring of the left ventricle was the reference of the segmentation network. To assess the image reconstruction quality, structural similarity index, peak signal‐to‐noise ratio, normalized root‐mean‐square error, and blind grading by two experienced cardiologists (5: excellent; 1: poor) were performed. To assess the segmentation performance, quantification of the LVEF on GRE imaging at 3 T was compared with the quantification from manual contouring. Excellent performance was demonstrated by the proposed technique. In terms of image quality, there was no difference between L+S and the proposed DESIRE technique. For quantification analysis, the proposed DL method was not different to the manual segmentation method (p > 0.05) in terms of quantification of LVEF. The reconstruction time for DESIRE was ~32 s (including nonuniform fast Fourier transform [NUFFT]) per dynamic series (40 frames), while the reconstruction time of L+S with GPU acceleration was approximately 3 min. The DL segmentation takes less than 5 s. In conclusion, the proposed DL‐based image reconstruction and quantification techniques enabled 1‐min image reconstruction for the whole heart and quantification with automatic reconstruction and quantification of the left ventricle function for high‐resolution spiral real‐time cine imaging with excellent performance. [ABSTRACT FROM AUTHOR]

In this article, we propose a novel radiant floor cooling system employing phase change materials (PCMs) with the applicability of a thermal energy simulation (TES) using two different TESs (spiral and counter). The numerical simulation was done with the help of a computational fluid dynamic program tool, namely, the ANSYS FLUENT 2022R2 software package. The results indicated that the cooling system’s performance is not greatly improved by the water mass flow rate (0.5 kg/s). Such radiant floor cooling systems can be calculated and designed with the help of the model. The results also showed that the PCM took a long time to dissolve with respect to the counterblow model (144 min) more than the spiral model reached (130 min) and thus benefited from storing and reducing energy consumption during peak load. The results also showed the temperature range of melting during the charging process is about 27–29°C, while it ranges between 22 and 26°C) during the discharge process. It is found that, generally, the counter pattern is the best configuration, allowing better thermal homogenization.

Copyright of Diversitas Journal is the property of Diversitas Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The complex rutile ore containing TiO2 and ZrO2 exhibited a high economical value. To effectively recover TiO2 and ZrO2 from the raw sample, a complete gravity separation process including a spiral chute and a shaking table was proposed. Chemical constituents, phase, liberation degree and size distribution were firstly characterized by XRF, chemical analyses, XRD, EPMA-EDS and screening to understand the mineralogy. Then, two stages of spiral chute separation tests were performed to treat the complex rutile ore. A rough zircon concentrate containing 33.18% ZrO2 was obtained after the first-stage spiral chute and a rough rutile concentrate containing 56.77% TiO2 was obtained after the second-stage spiral chute. To further improve the grade and recovery of ZrO2 and TiO2 in the rough products obtained by spiral chutes, shaking table tests were performed. A zircon concentrate containing 42.65% ZrO2 and a rutile concentrate containing 61.75% TiO2 were obtained. For the tailing of the first-stage spiral chute, a rutile product assaying 57.50% TiO2 was obtained, and the tailing was directly discarded as waste after the shaking table tests. Moreover, the distribution regularities of ZrO2 and TiO2 in the products were further revealed by XRD analyses. Finally, a closed-circuit beneficiation process was proposed to treat the complex rutile ore for achieving comprehensive and effective utilization. [ABSTRACT FROM AUTHOR]

Purpose: To demonstrate speech‐production real‐time MRI (RT‐MRI) using a contemporary 0.55T system, and to identify opportunities for improved performance compared with conventional field strengths. Methods: Experiments were performed on healthy adult volunteers using a 0.55T MRI system with high‐performance gradients and a custom 8‐channel upper airway coil. Imaging was performed using spiral‐based balanced SSFP and gradient‐recalled echo (GRE) pulse sequences using a temporal finite‐difference constrained reconstruction. Speech‐production RT‐MRI was performed with three spiral readout durations (8.90, 5.58, and 3.48 ms) to determine trade‐offs with respect to articulator contrast, blurring, banding artifacts, and overall image quality. Results: Both spiral GRE and bSSFP captured tongue boundary dynamics during rapid consonant‐vowel syllables. Although bSSFP provided substantially higher SNR in all vocal tract articulators than GRE, it suffered from banding artifacts at TR > 10.9 ms. Spiral bSSFP with the shortest readout duration (3.48 ms, TR = 5.30 ms) had the best image quality, with a 1.54‐times boost in SNR compared with an equivalent GRE sequence. Longer readout durations led to increased SNR efficiency and blurring in both bSSFP and GRE. Conclusion: High‐performance 0.55T MRI systems can be used for speech‐production RT‐MRI. Spiral bSSFP can be used without suffering from banding artifacts in vocal tract articulators, provide better SNR efficiency, and have better image quality than what is typically achieved at 1.5 T or 3 T. [ABSTRACT FROM AUTHOR]

Spiral heat exchangers are designed to meet the most difficult heat transfer challenges. Whether it's frequent dirt removal or limitations related to pressure drop and installation space, they are the ideal solution to problems for liquid-liquid and two-phase loads. Robust, efficient and compact models keep installation and maintenance costs extremely low. Compared to other heat exchangers commonly used in similar applications, spiral designs offer a compact footprint and increased thermal efficiency. Built with unique features that prevent fouling, they can handle the toughest heat transfer challenges while ensuring the most reliable performance. They work consistently, with extremely low installation and maintenance costs. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Polytechnic is the property of Journal of Polytechnic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The step-flow and spiral growth of a multicomponent crystal are considered from vapors, taking into account the different possible Schwoebel barriers for each component within the Burton-Cabrera-Frank model. Analytic expressions for the final growth rates of such a multicomponent crystal are determined while considering the kinetic properties of all the individual components and growth conditions. Possible instabilities inherent in the presence of several components are studied, and a stability criterion for the multicomponent case is proposed. It is shown that, in certain cases, nucleation of nanoislands of pure components behind the moving steps can initiate, significantly distorting the growth process. The criterion for the occurrence of such an unstable regime is found. [ABSTRACT FROM AUTHOR]

We present a case involving a 32-year-old man who ingested chlorine bleach with self-defeating intent. The ingestion of bleach can lead to a wide range of consequences, from mild mucosal burns to severe complications, rarely resulting in death. This case highlights the association between chlorine bleach ingestion and the development of hepatic portal venous gas (HPVG), a radiological finding traditionally thought to carry poor prognoses. The HPVG in this case resolved spontaneously within 24 h with conservative management, indicating its transient nature. The exact pathophysiological mechanisms responsible for HPVG after the ingestion of toxic substances.remain only partially understood. One hypothesis suggests that extensive damage to the gastrointestinal wall caused by caustic agent may allow enteric gas to enter the portal system. While HPVG after toxic ingestion is often transient, its consequences and potential risks should be carefully considered. Hyperbaric oxygen therapy is suggested in cases with neurological symptoms. In conclusion, HPVG is not a specific disease but rather a manifestation of various underlying factors, and its development in the context of chlorine bleach ingestion represents an additional insight to its understanding. It can be associated with severe medical conditions, but it is also found in less severe cases that can be managed conservatively. [ABSTRACT FROM AUTHOR]

Background: Body contour deformities that develop following massive weight loss involve almost all areas of the body. Breast management after massive weight loss is performed for cosmetic and reconstructive purposes. It is critical to realize how these abnormalities affect the breast to handle those patients effectively. Numerous studies demonstrated strategies to enhance breast projection, shape, and volume. These include breast reduction, augmentation using implants or local tissues of the chest wall, and/or the breast for breast auto-augmentation. In this study, the efficacy of a superior pedicle for nipple-areolar complex (NAC) together with a spiral flap for breast auto-augmentation and elimination of back rolls in massive weight patients is evaluated. Methods: This is a prospective case series study carried out on twenty female patients with massive weight loss and presenting for breast augmentation and/or lift. Breast auto-augmentation was done using a spiral flap harvested from the patient's back and superior pedicle for the nipple-areolar complex (NAC). Results were evaluated according to the surgeon's and patient's satisfaction scores. Results: The patients' age ranged between 20 and 42 years old with a mean age of 35 years old. Their BMI ranged from 24 to 32 kg/m2 with a mean BMI of 28.9 kg/m2.Complications were all minor in nature and did not affect the overall results. Eighty percent of surgeons rated the results as excellent with a mean score of 8.25 (SD 0.77, score range is 0–9). Regarding patient's satisfaction, the mean score was 13.15 with a maximum score of 15, which reflects the high satisfaction rate for the patients regarding the procedure and marked improvement in self-perception and body image. Conclusions: Spiral flap represents a good option for breast auto-augmentation in massive weight loss patients. In addition to the upper body lift achieved, the use of a superior pedicle for NAC provides a better superior fullness for the breast mound. A longer follow-up, a larger sample size, and comparative studies are needed to achieve a stronger argument and a higher level of evidence. Level of evidence: Level IV, Therapeutic. [ABSTRACT FROM AUTHOR]

Purpose: To present the validation of a new Flexible Ultra‐Short Echo time (FUSE) pulse sequence using a short‐T2 phantom. Methods: FUSE was developed to include a range of RF excitation pulses, trajectories, dimensionalities, and long‐T2 suppression techniques, enabling real‐time interchangeability of acquisition parameters. Additionally, we developed an improved 3D deblurring algorithm to correct for off‐resonance artifacts. Several experiments were conducted to validate the efficacy of FUSE, by comparing different approaches for off‐resonance artifact correction, variations in RF pulse and trajectory combinations, and long‐T2 suppression techniques. All scans were performed on a 3 T system using an in‐house short‐T2 phantom. The evaluation of results included qualitative comparisons and quantitative assessments of the SNR and contrast‐to‐noise ratio. Results: Using the capabilities of FUSE, we demonstrated that we could combine a shorter readout duration with our improved deblurring algorithm to effectively reduce off‐resonance artifacts. Among the different RF and trajectory combinations, the spiral trajectory with the regular half‐inc pulse achieves the highest SNRs. The dual‐echo subtraction technique delivers better short‐T2 contrast and superior suppression of water and agar signals, whereas the off‐resonance saturation method successfully suppresses water and lipid signals simultaneously. Conclusion: In this work, we have validated the use of our new FUSE sequence using a short T2 phantom, demonstrating that multiple UTE acquisitions can be achieved within a single sequence. This new sequence may be useful for acquiring improved UTE images and the development of UTE imaging protocols. [ABSTRACT FROM AUTHOR]

Purpose: This work proposes a 2D/3D hybrid inflow MRA technique for fast scanning and high SNR and contrast‐to‐noise (CNR) efficiencies. Methods: Localized quadratic (LQ) encoding was combined with a sliding‐slice spiral acquisition. Inflow MRAs around the circle of Willis and the carotid bifurcations were collected on four healthy volunteers. Spiral images were deblurred without or with water–fat separation for sliding‐slice LQ (ssLQ) out‐of‐phase (OP) and Dixon inflow MRAs, respectively. Results were compared to multiple overlapping thin slab acquisitions (MOTSA) and 2D OP inflow MRAs. Noise data were also acquired with RF and gradients turned off to compute maps of SNR and SNR efficiency. Quantitative assessment of relative contrast, CNR, and CNR efficiency for flow were performed in regions of interest. Results: The sliding‐slice spiral technique alone reduces scan time by 10% to 40% compared with a standard spiral acquisition scheme. The proposed spiral ssLQ OP achieves 50% higher scan speed than the spiral MOTSA with comparable SNR and CNR efficiencies, which are ∼100% higher than the Cartesian MOTSA for intracranial inflow MRAs. Spiral ssLQ Dixon inflow MRA provides better visibility for vessels around the fat compared to spiral ssLQ OP inflow MRA, with a trade‐off of scan speed. Spiral ssLQ MRA with thinner slice thickness is two to five times faster than the 2D Cartesian inflow neck MRA around the carotid bifurcations, while also achieving higher SNR efficiency. Conclusion: The proposed spiral ssLQ is a fast and flexible MRA method with improved SNR and CNR efficiencies over traditional Cartesian inflow MRAs. [ABSTRACT FROM AUTHOR]

Bongabong Waterworks and Sanitation Association (BOWASA) currently uses a traditional method of water billing that involves taking meter readings, calculating water usage per household, and issuing billing statements. A web-based system that automatically calculates water usage and generates billing statements was proposed and developed. SMS notifications were integrated to notify consumers’ bills, due dates, and disconnection notices, and consumers were able to pay bills using online payment technology. The spiral model was used as a software development method, and the system was tested and evaluated by BOWASA management, consumers, and IT experts using ISO 25010 software quality standards. The system was found to be user-friendly, interactive, and functional, achieving its expected functions in terms of functional suitability, performance efficiency, usability, compatibility, and security. It can greatly improve BOWASA management by streamlining transactions and services and providing consumers with accurate and timely information about their water consumption and bills. It also enhances convenience for consumers by enabling online payment and SMS notifications. Overall, the web-based system can increase efficiency, accuracy, and convenience for BOWASA and its consumers.

Based on the two postures of trunk roll-up and extension, a spiral spatial folding mechanism composed of multiple modules is designed. The geometric relationship between the modules is analyzed, and the endpoint positions of the modules are calculated by the D-H method. The influence of the angle, length, number and scaling factor of the modules on the spiral shape is discussed. The spiral shape is designed as a whole by dimensional optimization, and the design of the solar wing is used as an example to calculate the dimensional parameters with the maximum unfolding length as the objective function and the spiral range, spacing and rod size as the constraints. The 3D models of the solar wing and gripper applications are given, and the appropriate driving method is briefly described for each application. This mechanism has a wide range of applications and can provide some reference for the design of the spiral mechanism.

Abstract Abstract Health systems worldwide are implementing lung cancer screening programmes to identify early-stage lung cancer and maximise patient survival. Volumetry is recommended for follow-up of pulmonary nodules and outperforms other measurement methods. However, volumetry is known to be influenced by multiple factors. The objectives of this systematic review (PROSPERO CRD42022370233) are to summarise the current knowledge regarding factors that influence volumetry tools used in the analysis of pulmonary nodules, assess for significant clinical impact, identify gaps in current knowledge and suggest future research. Five databases (Medline, Scopus, Journals@Ovid, Embase and Emcare) were searched on the 21st of September, 2022, and 137 original research studies were included, explicitly testing the potential impact of influencing factors on the outcome of volumetry tools. The summary of these studies is tabulated, and a narrative review is provided. A subset of studies (n = 16) reporting clinical significance were selected, and their results were combined, if appropriate, using meta-analysis. Factors with clinical significance include the segmentation algorithm, quality of the segmentation, slice thickness, the level of inspiration for solid nodules, and the reconstruction algorithm and kernel in subsolid nodules. Although there is a large body of evidence in this field, it is unclear how to apply the results from these studies in clinical practice as most studies do not test for clinical relevance. The meta-analysis did not improve our understanding due to the small number and heterogeneity of studies testing for clinical significance. Critical relevance statement Many studies have investigated the influencing factors of pulmonary nodule volumetry, but only 11% of these questioned their clinical relevance in their management. The heterogeneity among these studies presents a challenge in consolidating results and clinical application of the evidence. Key points • Factors influencing the volumetry of pulmonary nodules have been extensively investigated. • Just 11% of studies test clinical significance (wrongly diagnosing growth). • Nodule size interacts with most other influencing factors (especially for smaller nodules). • Heterogeneity among studies makes comparison and consolidation of results challenging. • Future research should focus on clinical applicability, screening, and updated technology. Graphical abstract

PurposeQuantitative susceptibility mapping (QSM) has surfaced as a promising non-invasive quantitative biomarker that provides information about tissue composition and microenvironment. Recently, ultrashort echo time quantitative susceptibility mapping (UTE-QSM) has been investigated to achieve QSM of short T2 tissues. As the feasibility of UTE-QSM has not been demonstrated in the brain, the goal of this study was to develop a UTE-QSM with an efficient 3D cones trajectory and validate it in the human brain.Materials and methodsAn ultrashort echo time (UTE) cones sequence was implemented in a 3T clinical MRI scanner. Six images were acquired within a single acquisition, including UTE and gradient recalled echo (GRE) images. To achieve QSM, a morphology-enabled dipole inversion (MEDI) algorithm was incorporated, which utilizes both magnitude and phase images. Three fresh cadaveric human brains were scanned using the 3D cones trajectory with eight stretching factors (SFs) ranging from 1.0 to 1.7. In addition, five healthy volunteers were recruited and underwent UTE-QSM to demonstrate the feasibility in vivo. The acquired data were processed with the MEDI-QSM pipeline.ResultsThe susceptibility maps estimated by UTE-QSM showed reliable tissue contrast. In the ex vivo experiment, high correlations were found between the baseline (SF of 1.0) and SFs from 1.1 to 1.7 with Pearson's correlations of 0.9983, 0.9968, 0.9959, 0.9960, 0.9954, 0.9943, and 0.9879, respectively (all p-values < 0.05). In the in vivo experiment, the measured QSM values in cortical gray matter, juxtacortical white matter, corpus callosum, caudate, and putamen were 25.4 ± 4.0, -21.8 ± 3.2, -22.6 ± 10.0, 77.5 ± 18.8, and 53.8 ± 7.1 ppb, consistent with the values reported in the literature.ConclusionUltrashort echo time quantitative susceptibility mapping enables direct estimation of the magnetic susceptibility in the brain with a dramatically reduced total scan time by use of a stretched 3D cones trajectory. This technique provides a new biomarker for susceptibility mapping in the in vivo brain.

Introduction: A spiral clavicle plate has been accepted for its superior multidirectional compatibility in the treatment of midshaft clavicle fractures from a biomechanical perspective. However, the influence of the sextant angle (spiral level) definition on biomechanical performance has not been clarified. A conceptual finite element analysis was conducted to identify the advantages and drawbacks of spiral clavicle plates with various sextant angle definitions. Methods: Conventional superior and three different conceptual spiral plates with sextant angle definitions ranging from 45 to 135 degrees were constructed to restore an OTA 15-B1.3 midshaft clavicle fracture model. Three major loading scenarios (cantilever downward bending, axial compression, and axial torsion) were simulated to evaluate the reconstructed structural stiffness and the stress on the clavicle plate and bone screws. Results: The spiral clavicle plate demonstrated greater capability in resisting cantilever downward bending with an increase in sextant angle and showed comparable structural stiffness and implant stress compared to the superior clavicle plate. However, weakened resistance to axial compression load was noted for the spiral clavicle plate, with lowered stiffness and increased stress on the clavicle plate and screws as the spiral level increased. Conclusion: The spiral clavicle plate has been reported to offer multidirectional compatibility for the treatment of midshaft clavicle fractures, as well as geometric advantages in anatomical matching and reduced skin prominence after surgery. The current study supports that remarkable cantilever bending strength can be achieved with this plate. However, users must consider the potential drawback of lowered axial compression resistance in safety considerations.

Three-dimensional (3D) spirals are fascinating geometric shapes that are used in a variety of applications, such as textile fabric pattern and texture design, architecture, art, and engineering. In this paper, design of patterns using three-dimensional spirals are explored. The work began by discussing the mathematical properties of spirals and their applications. Then, several techniques for designing textile patterns are presented, including the use computer algorithms. Finally, examples of patterns that have been designed using spirals are presented. A comparative analysis was made with available literary sources. Guidelines for applying the obtained results in practice and guidelines for continuing this development are proposed.

Ultralow‐field (ULF) magnetic resonance imaging (MRI) can suffer from inferior image quality because of low signal‐to‐noise ratio (SNR). As an efficient way to cover the k‐space, the spiral acquisition technique has shown great potential in improving imaging SNR efficiency at ULF. The current study aimed to address the problems of noise and blurring cancelation in the ULF case with spiral trajectory, and we proposed a spiral‐out sequence for brain imaging using a portable 50‐mT MRI system. The proposed sequence consisted of three modules: noise calibration, field map acquisition, and imaging. In the calibration step, transfer coefficients were obtained between signals from primary and noise‐pick‐up coils to perform electromagnetic interference (EMI) cancelation. Embedded field map acquisition was performed to correct accumulated phase error due to main field inhomogeneity. Considering imaging SNR, a lower bandwidth for data sampling was adopted in the sequence design because the 50‐mT scanner is in a low SNR regime. Image reconstruction proceeded with sampled data by leveraging system imperfections, such as gradient delays and concomitant fields. The proposed method can provide images with higher SNR efficiency compared with its Cartesian counterparts. An improvement in temporal SNR of approximately 23%–44% was measured via phantom and in vivo experiments. Distortion‐free images with a noise suppression rate of nearly 80% were obtained by the proposed technique. A comparison was also made with a state‐of‐the‐art EMI cancelation algorithm used in the ULF‐MRI system. SNR efficiency‐enhanced spiral acquisitions were investigated for ULF‐MR scanners and future studies could focus on various image contrasts based on our proposed approach to widen ULF applications. [ABSTRACT FROM AUTHOR]

Health systems worldwide are implementing lung cancer screening programmes to identify early-stage lung cancer and maximise patient survival. Volumetry is recommended for follow-up of pulmonary nodules and outperforms other measurement methods. However, volumetry is known to be influenced by multiple factors. The objectives of this systematic review (PROSPERO CRD42022370233) are to summarise the current knowledge regarding factors that influence volumetry tools used in the analysis of pulmonary nodules, assess for significant clinical impact, identify gaps in current knowledge and suggest future research. Five databases (Medline, Scopus, Journals@Ovid, Embase and Emcare) were searched on the 21st of September, 2022, and 137 original research studies were included, explicitly testing the potential impact of influencing factors on the outcome of volumetry tools. The summary of these studies is tabulated, and a narrative review is provided. A subset of studies (n = 16) reporting clinical significance were selected, and their results were combined, if appropriate, using meta-analysis. Factors with clinical significance include the segmentation algorithm, quality of the segmentation, slice thickness, the level of inspiration for solid nodules, and the reconstruction algorithm and kernel in subsolid nodules. Although there is a large body of evidence in this field, it is unclear how to apply the results from these studies in clinical practice as most studies do not test for clinical relevance. The meta-analysis did not improve our understanding due to the small number and heterogeneity of studies testing for clinical significance. Critical relevance statement: Many studies have investigated the influencing factors of pulmonary nodule volumetry, but only 11% of these questioned their clinical relevance in their management. The heterogeneity among these studies presents a challenge in consolidating results and clinical application of the evidence. Key points: • Factors influencing the volumetry of pulmonary nodules have been extensively investigated. • Just 11% of studies test clinical significance (wrongly diagnosing growth). • Nodule size interacts with most other influencing factors (especially for smaller nodules). • Heterogeneity among studies makes comparison and consolidation of results challenging. • Future research should focus on clinical applicability, screening, and updated technology. [ABSTRACT FROM AUTHOR]

Purpose: The expanded encoding model incorporates spatially‐ and time‐varying field perturbations for correction during reconstruction. To date, these reconstructions have used the conjugate gradient method with early stopping used as implicit regularization. However, this approach is likely suboptimal for low‐SNR cases like diffusion or high‐resolution MRI. Here, we investigate the extent that ℓ1$$ {\ell}_1 $$‐wavelet regularization, or equivalently compressed sensing (CS), combined with expanded encoding improves trade‐offs between spatial resolution, readout time and SNR for single‐shot spiral DWI at 7T. The reconstructions were performed using our open‐source graphics processing unit‐enabled reconstruction toolbox, "MatMRI," that allows inclusion of the different components of the expanded encoding model, with or without CS. Methods: In vivo accelerated single‐shot spirals were acquired with five acceleration factors (R) (2×–6×) and three in‐plane spatial resolutions (1.5, 1.3, and 1.1 mm). From the in vivo reconstructions, we estimated diffusion tensors and computed fractional anisotropy maps. Then, simulations were used to quantitatively investigate and validate the impact of CS‐based regularization on image quality when compared to a known ground truth. Results: In vivo reconstructions revealed improved image quality with retainment of small features when CS was used. Simulations showed that the joint use of the expanded encoding model and CS improves accuracy of image reconstructions (reduced mean‐squared error) over the range of R investigated. Conclusion: The expanded encoding model and CS regularization are complementary tools for single‐shot spiral diffusion MRI, which enables both higher spatial resolutions and higher R. [ABSTRACT FROM AUTHOR]

Purpose: To mitigate signal variations caused by inhomogeneous RF and magnetization decay in hyperpolarized 129Xe ventilation images using flip‐angle maps generated from sequential 2D spiral ventilation images acquired in a breath‐hold. Images and correction maps were compared with those obtained using conventional, 2D gradient‐recalled echo. Theory and Methods: Analytical expressions to predict signal intensity and uncertainty in flip‐angle measurements were derived from the Bloch equations and validated by simulations and phantom experiments. Imaging in 129Xe phantoms and human subjects (1 healthy, 1 cystic fibrosis) was performed using 2D gradient‐recalled echo and spiral. For both sequences, consecutive images were acquired with the same slice position during a breath‐hold (Cartesian scan time = 15 s; spiral scan time = 5 s). The ratio of these images was used to calculate flip‐angle maps and correct intensity inhomogeneities in ventilation images. Results: Mean measured flip angle showed excellent agreement with the applied flip angle in simulations (R2 = 0.99) for both sequences. Mean measured flip angle agreed well with the globally applied flip angle (∼15% difference) in 129Xe phantoms and in vivo imaging using both sequences. Corrected images displayed reduced coil‐dependent signal nonuniformity relative to uncorrected images. Conclusions: Flip‐angle maps were obtained using sequentially acquired, 2D spiral, 129Xe ventilation images. Signal intensity variations caused by RF‐coil inhomogeneity can be corrected by acquiring sequential single‐breath ventilation images in less than 5‐s scan time. Thus, this method can be used to remove undesirable heterogeneity while preserving physiological effects on the signal distribution. [ABSTRACT FROM AUTHOR]

Purpose: To compare conventional CT images and virtual monoenergetic images (VMI) at dual-layer dual-energy CT (dlDECT) in patients with colorectal cancer (CRC) through quantitative analysis and to investigate the added value of VMI. Material and Methods: Sixty-six consecutive patients with histologically documented CRC and available VMI reconstructions were retrospectively investigated. Subsequently, forty-two patients, without any colonic disease at colonoscopy, were selected as control group. Conventional CT images and VMI reconstructions at energy levels ranging from 40 (VMI40) to 100 keV (VMI100) in 10 keV increments, were obtained from the late arterial phase. First, signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were obtained to select the best VMI reconstruction. Finally, the diagnostic accuracy of conventional CT and VMI40 in late arterial phase was evaluated. Results: On quantitative analysis, SNR and CNR were higher for VMI40 (19.5 ± 7.7 and 11.8 ± 6.2, respectively) with statistically significant differences compared to conventional CT (P < 0.05) and all the other VMI reconstructions (P < 0.05), except for VMI50 (P > 0.05). The addition of VMI40 to conventional CT images significantly improved the area under the curve (AUC) for the diagnosis of CRC, increasing it from 0.875 to 0.943 for reader 1 (P < 0.05) and from 0.916 to 0.954 for reader 2 (P < 0.05). The improvement was greater in the less experienced radiologist (0.068) compared to the more experienced one (0.037). Conclusion: VMI40 has showed the highest quantitative image parameters. Furthermore, the use of VMI40 can lead to a significant improvement in the diagnostic performance for detecting CRC. [ABSTRACT FROM AUTHOR]

Hyperpolarized 129Xe MRI (Xe‐MRI) is increasingly used to image the structure and function of the lungs. Because 129Xe imaging can provide multiple contrasts (ventilation, alveolar airspace size, and gas exchange), imaging often occurs over several breath‐holds, which increases the time, expense, and patient burden of scans. We propose an imaging sequence that can be used to acquire Xe‐MRI gas exchange and high‐quality ventilation images within a single, approximately 10 s, breath‐hold. This method uses a radial one‐point Dixon approach to sample dissolved 129Xe signal, which is interleaved with a 3D spiral ("FLORET") encoding pattern for gaseous 129Xe. Thus, ventilation images are obtained at higher nominal spatial resolution (4.2 × 4.2 × 4.2 mm3) compared with gas‐exchange images (6.25 × 6.25 × 6.25 mm3), both competitive with current standards within the Xe‐MRI field. Moreover, the short 10 s Xe‐MRI acquisition time allows for 1H "anatomic" images used for thoracic cavity masking to be acquired within the same breath‐hold for a total scan time of about 14 s. Images were acquired using this single‐breath method in 11 volunteers (N = 4 healthy, N = 7 post‐acute COVID). For 11 of these participants, a separate breath‐hold was used to acquire a "dedicated" ventilation scan and five had an additional "dedicated" gas exchange scan. The images acquired using the single‐breath protocol were compared with those from dedicated scans using Bland–Altman analysis, intraclass correlation (ICC), structural similarity, peak signal‐to‐noise ratio, Dice coefficients, and average distance. Imaging markers from the single‐breath protocol showed high correlation with dedicated scans (ventilation defect percent, ICC = 0.77, p = 0.01; membrane/gas, ICC = 0.97, p = 0.001; red blood cell/gas, ICC = 0.99, p < 0.001). Images showed good qualitative and quantitative regional agreement. This single‐breath protocol enables the collection of essential Xe‐MRI information within one breath‐hold, simplifying scanning sessions and reducing costs associated with Xe‐MRI. [ABSTRACT FROM AUTHOR]

Van der Waals (vdW) layered materials exhibit fruitful novel physical properties. The energy band of such materials depends strongly on their structures, and a tremendous variation in their physical properties can be deduced from a tiny change in inter‐layer spacing, twist angle, or in‐plane strain. In this work, a kind of vdW layered material of spiral antimonene is constructed, and the strain effects in the material are studied. The spiral antimonene is grown on a germanium (Ge) substrate and is induced by a helical dislocation penetrating through few atomic‐layers of antimonene (β‐phase). The as‐grown spiral is intrinsically strained, and the lattice distortion is found to be pinned around the dislocation. Both spontaneous inter‐layer twist and in‐plane anisotropic strain are observed in scanning tunneling microscope (STM) measurements. The strain in the spiral antimonene can be significantly modified by STM tip interaction, leading to a variation in the surface electronic density of states (DOS) and a large modification in the work function of up to a few hundreds of millielectron‐volts (meV). Those strain effects are expected to have potential applications in building up novel piezoelectric devices. [ABSTRACT FROM AUTHOR]

Objective: This study combines a deep image prior with low-rank subspace modeling to enable real-time (free-breathing and ungated) functional cardiac imaging on a commercial 0.55 T scanner. Materials and methods: The proposed low-rank deep image prior (LR-DIP) uses two u-nets to generate spatial and temporal basis functions that are combined to yield dynamic images, with no need for additional training data. Simulations and scans in 13 healthy subjects were performed at 0.55 T and 1.5 T using a golden angle spiral bSSFP sequence with images reconstructed using l 1 -ESPIRiT, low-rank plus sparse (L + S) matrix completion, and LR-DIP. Cartesian breath-held ECG-gated cine images were acquired for reference at 1.5 T. Two cardiothoracic radiologists rated images on a 1–5 scale for various categories, and LV function measurements were compared. Results: LR-DIP yielded the lowest errors in simulations, especially at high acceleration factors (R ≥ 8). LR-DIP ejection fraction measurements agreed with 1.5 T reference values (mean bias − 0.3% at 0.55 T and − 0.2% at 1.5 T). Compared to reference images, LR-DIP images received similar ratings at 1.5 T (all categories above 3.9) and slightly lower at 0.55 T (above 3.4). Conclusion: Feasibility of real-time functional cardiac imaging using a low-rank deep image prior reconstruction was demonstrated in healthy subjects on a commercial 0.55 T scanner. [ABSTRACT FROM AUTHOR]

A 56-year-old man with a previous right nephrectomy for multiple papillary renal cell carcinomas (pRCC) underwent a follow-up CT scan. Using a dual-layer dual-energy CT (dlDECT), we demonstrated the presence of a small amount of fat in a 2.5 cm pRCC that mimicked the diagnosis of angiomyolipoma (AML). Histological examination demonstrated the absence of macroscopic intratumoral adipose tissue, showing a fair amount of enlarged foam macrophages loaded with intracytoplasmic lipids. The presence of fat density in an RCC is an extremely rare occurrence in the literature. To our knowledge, this is the first description using dlDECT of a minimal amount of fat tissue in a small RCC due to the presence of tumor-associated foam macrophages. Radiologists should be aware of this possibility when characterizing a renal mass with DECT. The option of RCCs must be considered, especially in the case of masses with an aggressive character or a positive history of RCC. [ABSTRACT FROM AUTHOR]

The accumulated amount of information about human morphology is enormous and this leads to a suitable environment for a new qualitative leap in the understanding of the human body. Material and Methods: Scientific publications available online. The methodology is: heuristic formation of the goal, systematic thinking, holistic approach, and comparison between the up-to-date embryology facts with the modern theories in physics and the traditional holistic philosophies of China. Aim: The purpose of this report is to validate STHB from an embryological point of view. Results: The embryonic period provides clear evidence for the spiral theory of the human body, demonstrating the center, its boundary, the equal importance of negative and positive structures, the primordial scale and the transition to different sub-scales, its short duration, and the clear transition to the next period of life. Conclusion: Most axioms of the STHB could be validated by human embryo development. As a disadvantage, one can consider the weak anthropological demonstration of the typical human characteristics that distinguish him from the animal world.