Line Polarization Research Articles

The polarization signals of the solar K I D lines and their magnetic sensitivity

Aims. This work aims to identify the relevant physical processes in shaping the intensity and polarization patterns of the solar K I D lines through spectral syntheses, placing particular emphasis on the D2 line. Methods. The theoretical Stokes profiles were obtained by numerically solving the radiative transfer problem for polarized radiation considering one-dimensional semi-empirical models of the solar atmosphere. The calculations account for scattering polarization, partial frequency redistribution (PRD) effects, hyperfine structure (HFS), J- and F-state interference, multiple isotopes, and magnetic fields of arbitrary strength and orientation. Results. The intensity and circular polarization profiles of both D lines can be suitably modeled while neglecting both J-state interference and HFS. The magnetograph formula can be applied to both lines, without including HFS, to estimate weak longitudinal magnetic fields in the lower chromosphere. By contrast, modeling the scattering polarization signal of the D lines requires the inclusion of HFS. The amplitude of the D2 scattering polarization signal is strongly depolarized by HFS, but it remains measurable. A small yet appreciable error is incurred in the scattering polarization profile if PRD effects are not taken into account. Collisions during scattering processes have a clear depolarizing effect, although a quantitative analysis is left for a forthcoming publication. Finally, the D2 scattering polarization signal is particularly sensitive to magnetic fields with strengths around 10 G and it strongly depends on their orientation. Despite this, its center-to-limb variation relative to the amplitude at the limb is largely insensitive to the field strength and orientation. Conclusions. These findings highlight the value of the K I D2 line polarization for diagnostics of the solar magnetism, and show that the linear and circular polarization signals of this line are primarily sensitive to magnetic fields in the lower chromosphere and upper photosphere, respectively.

IL-37 improves mice myocardial infarction via inhibiting YAP-NLRP3 signaling mediated macrophage programming

ObjectiveMyocardial infarction is the highest cause of cardiovascular death. Previous studies found that patients with myocardial infarction have elevated serum IL-37 and IL-37 treatment significantly alleviates adverse remodeling in myocardial infarction mice. However, the underlying mechanism of IL-37 in myocardial infarction is still unknown. Here we explored the underlying mechanism of IL-37 in attenuating myocardial infarction. MethodsThe myocardial infarction mice model was constructed by left anterior descending ligation and then submitted to recombinant IL-37 administration. The histology and cardiac function were detected by HE & Masson staining and echocardiography, respectively. The macrophage phenotypes were analyzed by flow cytometry and real-time PCR. The cytokines in serum and cell culture supernatant were determined by ELISA. In addition, THP-1 cells were used in vitro to investigate the underlying mechanisms. ResultsInfarcted mice showed increased inflammatory cell infiltration and impaired cardiac function. IL-37 treatment alleviated pro-inflammatory macrophage infiltration, tissue injury, and collagen deposition in hearts on day 3 and 7 after infarction in mice. In addition, IL-37 application modulated the balance between M1 and M2 macrophages in infarcted hearts. In vitro, THP-1 cell line polarization was also regulated by IL-37, companied by YAP phosphorylation and NLRP3 inactivation. Verteporfin, a YAP inhibitor, could abolish IL-37-induced NLRP3 inhibition and M2 macrophage polarization. ConclusionOur results demonstrated that IL-37 achieves a favorable therapeutical function on myocardial infarction by modulating YAP-NLRP3 mediated macrophage programming, providing a promising drug for the treatment of myocardial infarction.

Macrophage polarization in placenta accreta and macrophage-trophoblast interactions.

Placenta accreta (PA) is defined by an abnormal invasion of placental trophoblasts into the myometrium, which can lead to serious postpartum complications. Macrophages play an important role in the regulation of trophoblast function. Both granulocyte colony-stimulating factor (G-CSF) and its receptor (granulocyte colony-stimulating factor receptor, G-CSFR) have effects on trophoblast invasion. However, the current understanding of G-CSF secretion, G-CSFR expression, abnormal polarization of decidual macrophages (dMϕ) in PA and the abnormal invasion of placental trophoblasts into the myometrium are limited. The polarization of dMϕ in PA was analyzed by flow cytometry (FCM), and the expression of G-CSFR in placental trophoblasts in PA was evaluated by immunohistochemistry. In an in vitro co-culture model, we investigated the effects of HTR-8/SVneo trophoblasts cell line (HTR-8) on macrophage human monocyte cell line (THP-1) polarization and G-CSF secretion, and we also analyzed the effects of THP-1 cells, especially M2-like subtype, on primary trophoblasts and HTR-8 proliferation, invasion, and adhesion. FCM, transwell assays, adhesion assays, and proliferation assays were used in the above model. Compared with controls (n = 9), dMϕ showed significantly lower levels of M1 markers CD80 and CD86 and higher levels of the M2 markers CD163 and CD206, and G-CSFR expression of placental trophoblasts was increased in PA (n = 5). In vitro experiments showed that the trophoblast HTR-8 cell line induced polarization of THP-1 cells to an M2-like subtype and increased their secretion of G-CSF. Furthermore, IL-4/IL-13-induced M2-like THP-1 macrophages were able to increase the expression of G-CSFR, proliferation, invasion and adhesion of both primary trophoblasts and HTR-8 trophoblasts. There is an altered immune imbalance at the maternal-fetal interface in PA, which further may lead to abnormal trophoblast function. G-CSF and its receptors may play important roles in abnormal polarization of macrophages and abnormal invasion of trophoblasts.

NMR-Based Metabolomic Imprinting Elucidates Macrophage Polarization of THP-1 Cell Lines Stimulated by Zinc Oxide Nanoparticles.

Zinc oxide (ZnO) nanoparticles (NPs) have been widely used in industry, cosmetics, drugs, bioimaging, and drug delivery. ZnO NPs have been found to interact and interfere with cellular physiology via macrophages, thereby resulting in macrophage polarization. The functional reprogramming of the cells is synchronized through cellular metabolic adaptations. The current study, therefore, aims to establish crosstalk between ZnO-NP-induced metabolic alterations and macrophage polarization in PMA-activated THP-1 cell lines. We observed moderate to heightened cytotoxic response in terms of cell viability and proliferation. The results also revealed increased Th1-type cytokine and chemokine expression. In order to characterize the changes in metabolite concentration in treatment groups, we employed multivariate data analysis (principal component analysis and partial least-squares discriminant analysis) of 1H NMR spectra. The results revealed biologically relevant patterns and alterations in many metabolic pathways. These alterations and patterns were found to be in line across the immune-cytotoxic axis. Furthermore, the results also implicate the role of carbon metabolism toward the classical activation of macrophage polarization. The omics approach could identify the markers involved in NP-induced toxicity, thus elaborating our vision of cytotoxicity that is currently limited to end-point and cytokine assays. Also, it could be emphasized that metabolic reconfiguration upon NP stimulation could direct macrophage polarization toward classical activation.

Influence of Thomson Electron Scattering Redistribution on Spectral Line Polarization Formed in Spherically Symmetric Extended and Expanding Atmospheres

Scattering of line photons by ambient electrons in thermal motion in the stellar atmosphere modifies the wings of both intensity and linear polarization profiles of the spectral lines. The aim of the present paper is to investigate in detail the influence of Thomson electron scattering redistribution on resonance line polarization formed in spherically symmetric extended and expanding atmospheres. A comoving frame method based on the accelerated lambda iteration technique is used to solve the concerned spherically symmetric polarized transfer equation including both the atomic and Thomson electron scattering redistribution functions. Our numerical studies highlight the importance of accounting for Thomson electron scattering redistribution in spectral line polarization problems.

Synthetic Polarization Maps of an Outflow Zone from Magnetohydrodynamic Simulations

The canonical theory of star formation in a magnetized environment predicts the formation of hourglass-shaped magnetic fields during the prestellar collapse phase. In protostellar cores, recent observations reveal complex and strongly distorted magnetic fields in the inner regions that are sculpted by rotation and outflows. We conduct resistive, nonideal magnetohydrodynamic simulations of a protostellar core and employ the radiative transfer code POLARIS to produce synthetic polarization segment maps. A comparison of our mock-polarization maps based on the toroidal-dominated magnetic field in the outflow zone with the observed polarization vectors of SiO lines in Orion Source I shows a reasonable agreement when the magnetic axis is tilted at an angle θ = 15° with respect to the plane of the sky and if the SiO lines have a net polarization parallel to the local magnetic field. Although the observed polarization is from SiO lines and our synthetic maps are due to polarized dust emission, a comparison is useful and allows us to resolve the ambiguity of whether the line polarization is parallel or perpendicular to the local magnetic field direction.

Calibration of Double-Plane-Mirror Catadioptric Camera Based on Coaxial Parallel Circles

A catadioptric camera with a double-mirror system, composed of a pinhole camera and two planar mirrors, can capture multiple catadioptric views of an object. The catadioptric point sets (CPSs) formed by the contour points on the object lie on circles, all of which are coaxial parallel. Based on the property of the polar line of the infinity point with respect to a circle, the infinity points in orthogonal directions can be obtained using any two CPSs, and a pole and polar pair with respect to the image of the absolute conic (IAC) can be obtained through inference of the Laguerre theorem. Thus, the camera intrinsic parameters can be solved. Furthermore, as the five points needed to fit the image of a circle are not easy to obtain accurately, only sets in which five points can be located can be obtained, whereas the points on the line of intersection between the two plane mirrors and the ground plane can easily be obtained accurately. An optimization method based on the analysis of neighboring point sets to compare the intersection points with an image of the center of multiple circle images fitted using the point sets is proposed. Bundle adjustment is then applied to further optimize the camera intrinsic parameters. The feasibility and validity of the proposed calibration methods and their optimization were confirmed through simulation and experiments. Two primary innovations were obtained from the results of this study: (1) by applying coaxial parallel circles to the double-plane-mirror catadioptric camera model, a variety of calibration methods were derived, and (2) we found that the overall model could be optimized by analyzing the features of the neighboring point set and bundle adjustment.

Standardization of Surgical Outcome Across the Tumor Complexity Spectrum in Robotic Partial Nephrectomy.

Introduction: Standardization of surgical steps or techniques can decrease error rates, increase efficiency, and ensure reproducible outcomes. In this study, we aimed to analyze the benefit of a standardized approach to robotic partial nephrectomy (RPN) on the reproducibility of outcomes across different tumor complexities. Methods: A single-center study of patients who have undergone a transperitoneal robotic-assisted partial nephrectomy for kidney cancer using the first assistant sparing technique between May 2014 and March 2022 was performed. Overall, 496 patients were included in the analysis. We compared clinical data and perioperative and postoperative outcomes for low, moderate, and high complexity score renal tumors. Tumor complexity was stratified using the Radius, Exophytic/Endophytic, Nearness to the collecting system or sinus, Anterior/Posterior, Location relative to the polar line nephrometry score. Data were compared using Kruskal-Wallis test, Chi-square test of Independence, and Fisher's exact test. Results: Of the patients in the study, 54.64% were low tumor complexities (n = 271), 40.32% were moderate tumor complexities (n = 200), and 5.04% were high tumor complexities (n = 25). High tumor complexity patients had significantly longer operative time (149 minutes versus 137 minutes moderate complexity versus 125 minutes low complexity, P = .001), longer ischemia time (12 minutes versus 11 minutes intermediate versus 10 minutes low complexity, P = .0001), and significant reduction in estimated glomerular filtration rate (-12.58 mL/min/1.73 m2 versus -5.51 mL/min/1.73 m2 intermediate versus -3.08 mL/min/1.73 m2 low complexity, P = .005). There was no significant difference in estimated blood loss (P = .074), blood transfusion rate (P = .454), postoperative complication rate (P = .527), surgical complication rate (P = .210), major complication rate (P = .098), length of hospital stay (P = .583), positive surgical margins (P = .872), and trifecta achievement (P = .740). Conclusion: Irrespective of tumor complexity, approaching RPN using a standardized approach will offer patients favorable perioperative outcomes. This approach has standardized our preoperative counseling, patient expectation, and postoperative surgical pathway across the tumor complexity spectrum.

Polarization transformation and destructive interference on subwavelength magnetic domains in magneto-plasmonic systems

We demonstrate magneto-optical (MO) polarization transformation due to surface plasmons in CoPt perpendicular magnetic films in the polar Kerr geometry. An extraordinary Kerr rotation angle (θK = ± 88.9°) that almost reaches the upper limit of polarization is produced in the attenuated total reflection (Kretschmann) configuration. P-polarized incident radiation is almost transformed upon reflection to s-polarized radiation, which may be out of phase depending on whether the magnetization of CoPt is up or down. Moreover, the reflected intensity may be drastically modulated by applying an external magnetic field. The reflectivity goes almost to zero in the demagnetized state and increases with increasing external magnetic field. This drastic optical response is attributed to the MO destructive interference produced by the subwavelength magnetic domain structure.

Safety and Effectiveness of Transhepatic Access for Percutaneous Renal Mass Cryoablation: A Multicenter Cohort

PurposeTo establish transhepatic percutaneous cryoablation of renal masses as a safe and effective approach. Materials and MethodsA retrospective review of records from 3 separate medical centers was performed identifying 23 patients (median age, 63 years [range 41–84 years]; 12 female [52.2%]) who underwent percutaneous transhepatic cryoablation for right-sided renal masses (median diameter, 2.4 cm [1.5–4.6 cm]) between 2008 and 2021. The median radius, exophytic/endophytic, nearness to collecting system or sinus, anterior/posterior, and location relative to polar lines (RENAL) nephrometry score was 5 (4–10). Adverse events (AEs) were classified according to the Society of Interventional Radiology (SIR) and Clavien-Dindo (CD) classifications. Primary and secondary technical success of each procedure were recorded. ResultsRenal cell carcinoma (of any subtype) was found in 10 (71.5%) of the 14 masses that were biopsied. Tract cautery was used for transhepatic probes in 14 (63.6%) of 22 procedures. Three (13%) of 23 patients had postprocedural AEs. Two cases (8.6%) were hemorrhages related to transhepatic access (SIR moderate-2, CD 2; SIR severe-3, CD 1), and 1 case (4.4%) was related to bowel injury (SIR severe-3, CD 3a). There were no instances of pneumothorax. Tract cautery was used in the procedures that resulted in an AE. Primary technical success was achieved in 84.2% (16/19) of procedures, whereas secondary technical success was achieved in 2 additional patients. The secondary technical success rate was 94.7% (18/19). Four patients did not have imaging follow-up. ConclusionsThe transhepatic approach to cryoablation of renal masses appears to have an acceptable safety profile and technical success rate. Larger studies, preferably comparative to nontranshepatic approach, are recommended.

Polarization singularities hidden in a deep subwavelength confined electromagnetic field with angular momentum.

Topologies associated with polarization point and line singularities can provide tools for controlling light propagation. By using the Stokes parameter, we demonstrate the emergence of polarization singularities hidden in deep subwavelength confined electromagnetic fields with angular momentum. We show that when the incoming orbital angular momentum is appropriately chosen, highly confined electromagnetic fields with super-diffraction-limited spatial dimensions can be obtained. At the same time, a conversion of orbital to spin angular momentum occurs, leading to a non-trivial topology. Our method provides a platform for developing topological photonics and studying the behavior of polarization singularities under strong focusing.

Solubility, sorption isotherms and thermodynamic parameters of β-cyclodextrin complexes with poplar propolis components: Practical implicances

The aim of this work was to establish experimental conditions to improve water solubility of poplar propolis components by complexation with β-cyclodextrin (BCD). Water sorption properties, stability constants and thermodynamic parameters of the encapsulation process were studied. Propolis greatly modified BCD sorption isotherms, being water sorption lower in propolis-BCD system. These results are consistent with the displacement of water molecules from the inner cavity of the BCD by propolis components and evidence propolis component-BCD interactions. Results showed a positive linear relationship between phenolic compounds water solubility and the BCD amount in aqueous solution. The solubility increase depends on the polarity and spatial geometry of these components. Phase solubility data indicated the formation of 1:1 M ratio complexes and studies at different temperatures allowed to calculate the stability constants and the thermodynamic parameters of the inclusion process. The negative ΔH (−22 kJ mol−1) and ΔG (−12.8 kJ mol−1) values indicate that the inclusion of propolis components in BCD is an exothermic and spontaneous process, respectively, that is mainly enthalpy driven. The obtained ΔS (-32 J mol−1.K−1) is typical of low energy interactions. Present results could be of interest to develop aqueous propolis formulations avoiding the use of organic solvents and without undesirable tastes or flavors.

GPR antennas geometry and its impact over detection of near-surface water contamination through AVO Data analysis at laboratory site

Polarization is an important technique for ground penetrating radar (GPR) surveys, particularly when determining the shape, orientation, size, and precise location of any buried material. A linearly-polarized incident GPR wave experiences polarization change upon scattering from the host medium, which highly depends upon the technique and antenna orientation used for the acquisition of the GPR data. This paper focuses on the polarization of GPR data acquired at a laboratory test site. We kept the GPR antenna orientation and geometry in mind to understand how they impact the results while detecting subsurface contamination. Because of its direct indication ability, amplitude variation with offset (AVO) has been widely used to detect subsurface contamination; however, a technique to evaluate the distribution of subsurface contamination is not yet available; thus, in this study, we will also discuss the distribution of contamination using polarization of GPR data. Two major phenomena have been studied: the polarity of the data acquired and slice view with and without contamination in the testing tank, as well as trace, frequency, and amplitude plot during data analysis to determine the difference of plot with and without contamination. Our findings suggest that using the polarization geometry technique to obtain an accurate view of the subsurface contamination will not only improve the GPR AVO analysis but will also provide a clear distribution of contamination in the subsurface.

A pilot study investigating the feasibility of using a fully automatic software to assess the RENAL and PADUA score.

Image-based morphometric scoring systems such as the RENAL and PADUA scores are useful to evaluate the complexity of partial nephrectomy for renal cell carcinoma (RCC). The main aim of this study was to develop a new imaging software to enable an automatic detection and a 3D visualization of RCC from CT angiography (CTA) and to address the feasibility to use it to evaluate the features of the RENAL and the PADUA scores. A training dataset of 210 patients CTA-scans manually segmented was used to train a deep learning algorithm to develop the automatic detection and 3D-visualization of RCC. A trained operator blindly assessed the RENAL and PADUA scores on a testing dataset of 41 CTA from patients with RCC using a commercialized semi-automatic software (ground truth) and the new automatic software. Concordance between the two methods was evaluated. The median PADUA score was 9 (7-11) and the renal score was 8 (5.5-9). The automatic software enabled to automatically detect the tumoral kidney and provided a 3D-visualization in all cases, with a computational time less than 20 seconds. Concordances for staging the anatomical features of the RENAL scores were respectively: 87.8% for radius, 85.4% for exophytic rate, 82.9% for location to the polar lines and 92.7% for the antero-posterior location. For the PADUA scores, concordances were 90.2% for tumor size, 85.4% for exophytic rate, 87.8% for polar location and 100% for renal rim. By enabling an automatic 3D-visualization of tumoral kidney, this software could help to calculate morphometric scores, save time and improve reproducibility for clinicians.

Targeted Renal Biopsy: Predictors on Imaging

Abstract Objectives The renal nephrometry score uses imaging characteristics such as lesion diameter, location, and proximity to hilar vessels to categorize renal masses by complexity for preoperative planning. These characteristics may also be used to determine the best approach to targeted renal biopsy. This study was conducted to investigate the impact of renal lesion characteristics as measured by the renal nephrometry score on the choice of modality used for performing a targeted renal lesion biopsy and increasing the chance of yielding a diagnostic biopsy. Materials and Methods All targeted computed tomography (CT)/ultrasound-guided renal biopsies performed by our radiology department from January 2017 to February 2020 were reviewed. Radiological characteristics and pathological outcomes were recorded with data on lesion size/ side, location in craniocaudal/anterior–posterior planes, endophytic/exophytic/mixed nature, and skin-lesion distance. Statistical Analysis Chi-squared tests, multivariate analysis, and t-tests were used in this study. Results Of the 145 consecutive patients included in the study, 86.2% (125/145) biopsies were diagnostic. About 54.5% (79/145) biopsies were ultrasound-guided, while 45.5% (66/145) were CT-guided. About 62.1% (90/145) biopsies revealed renal cell carcinoma. The highest rate of diagnostic biopsy was in the exophytic, laterally positioned mass either entirely below lower polar or above upper polar line. Ultrasound was preferred for lesions under 4cm and 4 to 7cm (p = 0.06). CT was used for anterior lesions and ultrasound for posterior and lateral lesions (p < 0.001). Of the 20 nondiagnostic biopsies, 7/20 had a repeat biopsy, 7/20 underwent surveillance, 5/20 underwent partial or total nephrectomy, and 1/20 underwent a pathological lymph node biopsy. Conclusions Our study highlights some factors radiologists should consider when predicting whether CT or ultrasound guidance is more appropriate and the probability of achieving a diagnostic biopsy based on lesion characteristics. At our institution, both modalities achieved high accuracy, although we favored ultrasound in lateral, posterior, and small lesions. These factors should be weighed against local experience and preference.

Unplanned Conversion From Partial to Radical Nephrectomy: An Analysis of Incidence, Etiology, and Risk Factors.

Conversions from partial to radical nephrectomy are uncommon and reports on this topic are rare. In this study we present a detailed analysis of conversions from partial to radical nephrectomy in a single-institutional contemporary experience and provide an analysis of preoperative risk factors. Patients who underwent converted (cases) and completed (controls) partial nephrectomy from 2000 to 2015 were matched 1:1 for analysis. Perioperative imaging was reviewed and RENAL (for radius, exophytic/endophytic properties, anterior/posterior descriptor, and location relative to the polar line) nephrometry scores were calculated. Reasons for conversions were abstracted from operative reports. Multivariable conditional logistic regression analyses were used to assess preoperative risk factors for conversion. A total of 168 cases (6.1% of all partial nephrectomies) were identified and matched on tumor size, year of surgery, and surgical approach to 168 controls. Conversion rates decreased from 13% in 2000-2003 to 4% in 2012-2015. Oncologic considerations, such as concern for upstaging and positive margins, were the most cited (56%) reasons for conversion. On multivariable analyses, male sex (odds ratio 2.34; P = .03), Charlson score (odds ratio per 1-unit increase: 1.28; P = .03), posterior and middle (on anteroposterior axis) location (reference: anterior, odds ratio 2.83, P = .02 and odds ratio 6.38, P < .001, respectively) and hilar location (reference: peripheral/central, odds ratio 5.61; P < .001) were associated with increased odds of conversion. Rates of conversion from partial to radical nephrectomy in our experience were low and decreased over time. Preoperative characteristics such as hilar, posterior, and middle locations were significantly associated with conversions after controlling for tumor size, and offer guidance for operative planning and patient counseling.

Cost Implications of Routine Preoperative Blood Typing and Crossmatching Prior to Robot-Assisted Laparoscopic Partial Nephrectomy.

The surgical treatment of small renal masses has shifted from open to minimally invasive approaches. Preoperative blood typing and product orders often mirror the practices of the open era. We aim to define the rate of transfusion after robot-assisted partial laparoscopic nephrectomy (RAPN) at an academic medical center and the costs associated with current practice. A retrospective review of an institutional database was utilized to identify patients who underwent RAPN and transfusion of blood products. Patient, tumor and operative variables were identified. From 2008 to 2021, 804 patients underwent RAPN, with 9 (1.1%) patients requiring a transfusion. Comparison of the transfused group with nontransfused patients yielded a significant difference in mean operative blood loss (527.8 ml vs 162.5 ml, p <0.0001), R.E.N.A.L. (for radius, exophytic/endophytic, nearness of tumor to collecting system, anterior/posterior, location relative to polar line) nephrometry score (7.1 vs 5.9, p <0.05), hemoglobin (11.3 gm/dl vs 13.9 gm/dl, p <0.05) and hematocrit (34.2% vs 41.4%, p <0.05). The variables associated with transfusion on univariate analysis were examined for predictive capacity using logistic regression. Operative blood loss (p <0.05), nephrometry score (p=0.05), hemoglobin (p <0.05) and hematocrit (p <0.05) remained associated with a transfusion. The hospital charge for blood typing and crossmatching was $1,320 USD per patient. With the maturity of RAPN techniques and outcomes, the extent of preoperative testing related to blood products should evolve to better reflect current procedural risks. Prioritizing testing resources for patients at increased complication risk can be based on predictive factors.

From the flow to the polarization field: A cognitive way for ferroelectric vortex structures

The generation of topological domain structures can significantly influence the behaviors of ferroelectric materials, and, however, strategies and perspectives for treating and analyzing them are still lacking. Inspired by the fluid lines and vorticity in hydromechanics, a characterization method of polarization lines and polarization vorticity is proposed herein for characterizing the vortex structure evolution. The polarization vorticity has the same unit as charge density, and the polarization vortex size is identified as a structure for vorticity concentration. Observing the radius and vorticity of vortices, we find that the domain evolution can be divided into three stages and the vortices react to mechanical loading in two ways: increasing the vorticity and enlarging the radius. Moreover, vortices exhibit three-dimensional shape, just like the vortex tube, and their conservation is proved. This paper provides a basis for further research on topological domain structures and the mechanism of vortex evolution, which might help improve high energy density devices.

Track width measurement in heat-assisted magnetic recording systems using the cross-track DC noise method

This paper uses a cross-track DC noise measurement technique to determine the written track width in heat-assisted magnetic recording (HAMR). The method is approached as a simple, no-extra-hardware-required technique on a spin-stand to determine the written track width as well as the DC noise amplitude at the center track in a HAMR system. The track width data show the expected trends with changing laser operating current () and write current (), and they are strongly correlated with track density capabilities and physical near-field transducer (NFT) peg width. The written track width is essentially defined by the which increases as increases. The method is useful for comparing the magnetic responses of different writer pole or NFT peg geometries, as well as media design comparison to provide insight into the head/component necessary to improve HAMR system performance, which is useful HAMR recording parameters for head/media designers and test engineers.

Influence of geometry of iron poles on the cogging torque of a field control axial flux permanent magnet machine

The paper presents 3D-FEA results of electromagnetic torque characteristics of a Field Control Axial Flux Permanent Magnet Machine (FCAFPMM) obtained for different pole shapes. The influence of the angular span of iron and permanent magnet poles on the cogging torque performance has been analysed at different excitations of an additional stator winding.