Search Results (511)

Background: Abdominal wall endometriosis (AWE) is a rare pathological condition that mostly occurs in the post-cesarean section. This study aimed to describe the surgical approach employed in treating 31 patients at our center over the past decade and compare the outcomes with those reported in scientific literature. Methods: We retrospectively evaluated the data of 31 patients with a cesarean section history who underwent surgery for AWE excision between 1 November 2012, and 31 January 2023, at the University of Naples Federico II, Italy. Subsequently, we reviewed the scientific literature for all AWE-related studies published between 1 January 1995, and 31 July 2024. Results: Most women presented with a palpable abdominal mass (90.3%) at the previous surgical site associated with cyclic abdominal pain (80.6%) concomitant with menstruation. All patients underwent preoperative abdominal ultrasound and magnetic resonance imaging, 71% underwent computed tomography, and 32.2% received ultrasound-guided needle biopsies. Furthermore, 90.3% and 9.7% had previous Pfannenstiel and median vertical surgical incisions, respectively. All patients underwent laparotomic excision and abdominal wall reconstruction, with prosthetic reinforcement used in 73.5% of cases. No recurrent nodules were detected in any patient at the 12-month follow-up. Conclusions: AWE should be suspected in women with a history of cesarean section presenting with palpable, cyclically painful abdominal mass associated with the menstrual cycle. Preoperative ultrasound and magnetic resonance imaging are essential, and surgical excision must ensure clear margins. Abdominal wall reconstruction should include prosthetic reinforcement, except when the defect is minimal (≤1.5 cm). An ultrasound follow-up at 12 months is recommended to confirm the absence of recurrence. Full article

Background and Objective: Temperature management is key for reliable operation of permanent magnet synchronous motors (PMSMs). The lumped-parameter thermal network (LPTN) is fast and interpretable but struggles with nonlinear behavior under high power density. We propose OLTEM, a physics-informed deep model that combines LPTN with a thermal neural network (TNN) to improve prediction accuracy while keeping physical meaning. Methods: OLTEM embeds LPTN into a recurrent state-space formulation and learns three parameter sets: thermal conductance, inverse thermal capacitance, and power loss. Two additions are introduced: (i) a state-conditioned squeeze-and-excitation (SC-SE) attention that adapts feature weights using the current temperature state, and (ii) an enhanced power-loss sub-network that uses a deep MLP with SC-SE and non-negativity constraints. The model is trained and evaluated on the public Electric Motor Temperature dataset (Paderborn University/Kaggle). Performance is measured by mean squared error (MSE) and maximum absolute error across permanent-magnet, stator-yoke, stator-tooth, and stator-winding temperatures. Results: OLTEM tracks fast thermal transients and yields lower MSE than both the baseline TNN and a CNN–RNN model for all four components. On a held-out generalization set, MSE remains below 4.0 °C² and the maximum absolute error is about 4.3–8.2 °C. Ablation shows that removing either SC-SE or the enhanced power-loss module degrades accuracy, confirming their complementary roles. Conclusions: By combining physics with learned attention and loss modeling, OLTEM improves PMSM temperature prediction while preserving interpretability. This approach can support motor thermal design and control; future work will study transfer to other machines and further reduce short-term errors during abrupt operating changes. Full article

Modern electronic devices such as smartphones, wearable devices, and robots typically integrate three-dimensional sensors to track the device’s movement in the 3D space. However, sensor measurements in three-dimensional vectors are highly sensitive to device orientation since a slight change in the device’s tilt or heading can change the vector values. To avoid complications, applications using these sensors often use only the magnitude of the vector, as in geomagnetic-based indoor positioning, or assume fixed device holding postures such as holding a smartphone in portrait mode only. However, using only the magnitude of the vector loses the directional information, while ad hoc posture assumptions work under controlled laboratory conditions but often fail in real-world scenarios. To resolve these problems, we propose a universal vector calibration algorithm that enables consistent three-dimensional vector measurements for the same physical activity, regardless of device orientation. The algorithm works in two stages. First, it transforms vector values in local coordinates to those in global coordinates by calibrating device tilting using pitch and roll angles computed from the initial vector values. Second, it additionally transforms vector values from the global coordinate to a reference coordinate when the target coordinate is different from the global coordinate by correcting yaw rotation to align with application-specific reference coordinate systems. We evaluated our algorithm on geomagnetic field-based indoor positioning and bidirectional step detection. For indoor positioning, our vector calibration achieved an 83.6% reduction in mismatches between sampled magnetic vectors and magnetic field map vectors and reduced the LSTM-based positioning error from 31.14 m to 0.66 m. For bidirectional step detection, the proposed algorithm with vector calibration improved step detection accuracy from 67.63% to 99.25% and forward/backward classification from 65.54% to 100% across various device orientations. Full article

The Halbach array permanent magnet can improve the power density of motors. This paper uses analytical modeling to analyze and optimize the Halbach array permanent magnet synchronous motor (PMSM). Firstly, a general motor model is established to obtain the air gap flux density. Secondly, the flux linkage and back electromotive force (EMF) were calculated. The analytical results are consistent with the finite element model (FEM) results. Thirdly, the effects of slot opening, magnetization angle, and main magnetic pole width on air gap flux density and back-EMF were studied. Finally, based on the optimization results, a prototype was manufactured, and performance testing was conducted successfully. Verification of the back-EMF of the prototype shows that the relative errors between FEM and the measured values are 1.1%, and the relative errors between the analytical values and measured values are 1.6%, which verifies the accuracy of the proposed analytical modeling. The proposed analytical model is universal and can be used to quickly adjust the magnetization form, magnetization angle, and pole width without remodeling in the finite element software, which is convenient for optimizing parameters in the early stage of motor design. Full article

We consider the scattering of electromagnetic radiation by a spherical particle, known as Mie scattering. The electric and magnetic fields are represented by multipole fields, and the amplitudes are the Mie scattering coefficients. Properties of the particle are mainly contained in these coefficients. We have studied the dependence of these coefficients on the various parameters, with an emphasis on the dependence on the particle radius. Central to this discussion is what is known as the ‘Mie circle’. Without absorption in the particle or the embedding medium, the Mie scattering coefficients lie on this universal circle in the complex plane. We have studied the location of the Mie scattering coefficients on this circle as a function of the particle radius. The Mie circle also serves as a reference for the case when there is absorption in the particle or the medium. In the limit of a small particle, a peculiar divergence appears in the expression for the Mie coefficients, known as the Fröhlich resonance. We show that this apparent singularity is a consequence of the fact that the limit of a small particle fails in the neighborhood of this resonance, and we derive an expression for the correct small-particle limit in the neighborhood of this resonance. Full article

We discuss different quench protocols for Ising and XY spin chains in a transverse magnetic field. With a sudden local magnetic field quench as a starting point, we generalize our approach to a large class of local non-sudden quenches. Using finite time path field theory (FTPFT) perturbative methods, we show that the difference between the sudden quench and a class of quenches with non-sudden switching on the perturbation vanishes exponentially with time, apart from non-substantial modifications that are systematically accounted for. As the consequence of causality and analytic properties of functions describing the discussed class of quenches, this is true at any order of perturbation expansion and thus for the resummed perturbation series. The only requirements on functions describing the perturbation strength switched on at a finite time $t=0$ are as follows: (1) their Fourier transform $f\left(p\right)$ is a function that is analytic everywhere in the lower complex semiplane, except at the simple pole at $p=0$ and possibly others with $\Im \left(p\right)<0$; and (2) $f\left(p\right)/p$ converges to zero at infinity in the lower complex semiplane. A prototypical function of this class is $tanh\left(\eta t\right)$, to which the perturbation strength is proportional after the switching at time $t=0$. In the limit of large $\eta$, such a perturbation approaches the case of a sudden quench. It is shown that, because of this new type of universal behavior of Loschmidt echo (LE) that emerges in an exponentially short time scale, our previous results for the sudden local magnetic field quench of Ising and XY chains, obtained by the resummation of the perturbative expansion, extend in the long-time limit to all non-sudden quench protocols in this class, with non-substantial modifications systematically taken into account. We also show that analogous universal behavior exists in disorder quenches, and ultimately global ones. LE is directly connected to the work probability distribution, and the described universal behavior is therefore appropriate in potential concepts of quantum technology related to spin chains. Full article

To address the growing demand for environmentally friendly flexible sensors, here, a composite hydrogel of nanocellulose (NC) and polyvinyl alcohol (PVA) was designed and fabricated using Camellia oleifera shells as a sustainable alternative to petroleum-based raw materials. Firstly, NC was extracted from Camellia oleifera shells and modified with 2-chloropropyl chloride to obtain a nanocellulose-based initiator (Init-NC) for atomic transfer radical polymerization (ATRP). Subsequently, sulfonyl betaine methacrylate (SBMA) was polymerized by Init-NC initiating to yield zwitterion-functionalized nanocellulose (NC-PSBMA). Finally, the NC-PSBMA/PVA hydrogel was fabricated by blending NC-PSBMA with PVA. A Fourier transform infrared spectrometer (FT-IR), proton nuclear magnetic resonance spectrometer (¹H-NMR), X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), universal mechanical testing machine, and digital source-meter were used to characterize the chemical structure, surface microstructure, and sensing performance. The results indicated that: (1) FT-IR and ¹H NMR confirmed the successful synthesis of NC-PSBMA; (2) SEM, TEM, and alternating current (AC) impedance spectroscopy verified that the NC-PSBMA/PVA hydrogel exhibits a uniform porous structure (pore diameter was 1.1737 μm), resulting in significantly better porosity (15.75%) and ionic conductivity (2.652 S·m⁻¹) compared to the pure PVA hydrogel; and (3) mechanical testing combined with source meter testing showed that the tensile strength of the composite hydrogel increased by 6.4 times compared to the pure PVA hydrogel; meanwhile, it showed a high sensitivity (GF = 1.40, strain range 0–5%; GF = 1.67, strain range 5–20%) and rapid response time (<0.05 s). This study presents a novel approach to developing bio-based, flexible sensing materials. Full article

Background: Magnetic resonance imaging (MRI) plays a crucial role in staging and preoperative evaluation in osteosarcoma patient. Fewer studies have focused on 2-year survival, which reflects tumour aggressiveness and early disease progression. This study examines the association between MRI characteristics and 2-year survival outcomes in osteosarcoma to better understand the imaging characteristic of high-risk patients. Methods: A retrospective case–control study was conducted at a tertiary university hospital. Patients diagnosed with osteosarcoma between 2010 and 2022 were included if they had a pre-treatment MRI and at least 2 years of follow-up. MRI scans were reviewed by two blinded radiologists to assess tumour location, volume, growth pattern, presence of fluid–fluid levels (FFL), pathological fractures, skip metastases, neurovascular bundle involvement, regional lymphadenopathy, and physeal or joint involvement. Statistical analyses, including Fisher’s exact test, Chi-square test, and Mann–Whitney U test, were performed to determine associations between MRI features and survival outcomes. Results: Twenty-eight patients (n = 28) met the inclusion criteria. Larger tumour volume (>300 mls) was significantly associated with poorer 2-year survival (p = 0.008). The presence of skip metastases also correlated with worse outcomes (p = 0.041). While presence of FFL, concentric growth pattern, regional lymphadenopathy, and physeal involvement showed trends toward poorer prognosis, these associations were not statistically significant. Conclusions: MRI characteristics, particularly tumour volume and skip metastases, are significant prognostic indicators of 2-year survival in osteosarcoma. These findings highlight the potential role of MRI in risk stratification and treatment planning, aiding in the identification of high-risk patients that can help with management. Full article

Papapetrou showed that the covariant derivative of a Killing vector field satisfies Maxwell’s equations in vacuum. Papapetrou’s result is extended, in this article, and it is shown that the covariant derivative of a Killing vector field satisfies Maxwell’s equations in non-vacuum backgrounds as well if one allows electromagnetic currents of purely geometric origin. It is then postulated that every Killing vector field gives rise to a physical electromagnetic field and, in a non-vacuum background, a physical electromagnetic current—hereafter called Killing electromagnetic field and Killing electromagnetic current, respectively. It is shown that the Killing electromagnetic field of the flat FLRW (Friedmann–Lema$\hat{\mathrm{i}}$tre–Robertson–Walker) universe comprises a Killing magnetic field and a rotational Killing electric field; an upper bound on the Killing magnetic field is derived, and it is found that the upper bound is consistent with the current observational bounds on the cosmic magnetic field. Next, the time-like Killing vector of the Schwarzschild spacetime is shown to give rise to a radial Killing electric field. It is also shown that in the weak field regime—and far from the matter distribution—the back reaction of the radial Killing electric field changes the Schwarzschild metric to the Reissner–Nordström metric, establishing a partial converse of Wald’s result. Drawing upon Rainich’s work on Rainich–Riemann manifolds, the etiological question of how a physical electromagnetic field can arise out of geometry is discussed; it is also argued that detection of the Killing electric field of flat FLRW spacetime may be within the current experimental reach. Finally, this article discusses the relevance of Killing electromagnetic currents and the aforementioned transmutation of Schwarzschild spacetime to Reissner–Nordstrom spacetime, to Misner and Wheeler’s program of realizing “charge without charge”. Full article

This work investigates the dynamics of a charged scalar boson in the Melvin universe by solving the Klein–Gordon equation with minimal coupling in both inertial and non-inertial frames. Non-inertial effects are introduced through a rotating reference frame, resulting in a modified spacetime geometry and the appearance of a critical radius that limits the radial domain of the field. Analytical solutions are obtained under appropriate approximations, and the corresponding energy spectra are derived. The results indicate that both the magnetic field and non-inertial effects modify the energy levels, with additional contributions depending on the coupling between the rotation parameter and the quantum numbers. A numerical analysis is also presented, illustrating the behavior of the solutions for two characteristic magnetic field scales: one that may be considered extreme, of the order of the ones proposed to be produced in heavy-ion collisions, and another near the Planck scale. Full article

Background: The main mechanism of optic nerve damage in patients with pituitary adenoma (PA) is the pressure of optic chiasm. The retinal nerve fiber layer (RNFL), the ganglion cell layer (GCL)+, and GCL++ thickness measurement by optical coherence tomography (OCT), visual function evaluation, and magnetic resonance imaging (MRI) can be used to predict visual function recovery. In our study, we investigated the associations between visual acuity (VA), visual field (VF), RNFL, GCL changes, and the findings of MRI in patients with PA. Methods: This study was conducted in the Departments of Ophthalmology and Neurosurgery of the Lithuanian University of Health Sciences Hospital. A total of 25 patients diagnosed with PA were included in the study group, and 27 healthy subjects were included in the control group. The thickness of the RNFL and ganglion cell layer (GCL+, GCL++) and optic nerve disc diameter was analysed with OCT. Moreover, an MRI was performed for patients with PA. Results: The RNFL thickness around the optic disk measured preoperatively was reduced significantly in the temporal quadrant in PA patients compared with the control group (median (min; max); mean rank: 73.5 (52; 109); 58.39 vs. 69.5 (16; 168); 46.14; p = 0.038). We found that it was reduced significantly only in the inferior quadrant of the macro-PA group compared to the micro-PA group (median (min; max); mean rank: 99.5 (61; 115); 21.07 vs. 106.5 (90; 121); 32.15), p = 0.008, respectively). The RNFL thickness was reduced significantly only in the inferior quadrant of the non-active PA group compared to the active PA group (median (min; max); mean rank: 118.5 (49; 144); 17.42 vs. 130.5 (77; 156); 28.05), p = 0.028, respectively). RNFL thickness was reduced significantly only in the temporal quadrant in the PA with suprasellar extension group compared to the PA without suprasellar extension group (median (min; max); mean rank: 67.5 (16; 99); 21.66 vs. 72 (58; 168); 30.39), p = 0.036, respectively). Furthermore, GCL++ thickness was reduced significantly in total and in superior and inferior sectors of the PA with suprasellar extension group compared to the PA without suprasellar extension group (median (min; max); mean rank: 98.5 (57; 113); 21.8; 101 (61; 121); 21.48 and 102.5 (59; 116); 21.71 vs. 103.5 (95; 115); 30.2; 106.5 (90; 115); 30.61 and 104.5 (95; 113); 30.32), p = 0.043; p = 0.028 and p = 0.038, respectively). In the control group, significant positive correlations were found between optic disc area and the total RNFL thickness (r = 0.440, p < 0.001). In the PA group, significant correlations were observed between optic rim area and total RNFL thickness (r = 0.493, p < 0.001) and all quadrants, with the strongest in the nasal quadrant (r = 0.503, p < 0.001). A moderate to strong negative correlation was found between visual field (VF) defects and RNFL thickness, with the strongest correlation observed in the superior quadrant. Conclusions: OCT offers a detailed insight into the microscopic structural and functional changes throughout the entire visual pathway in patients with PA. Our findings demonstrate a significant negative correlation between RNFL thickness and visual field defects, highlighting the clinical relevance of OCT measurements in visual function assessment. Moreover, the results suggest that optic rim area may be a more reliable indicator of RNFL thickness variations than optic disc area in patients with PA. Full article

The agricultural sector is one of the most significant sectors of the global economy, yet it is concurrently a highly energy-intensive industry. The issue of optimizing field operations in terms of energy consumption is therefore a key consideration for sustainable agriculture, and the solution to this issue leads to both environmental and financial benefits. The aim of this study was to estimate energy consumption during soil cultivation using geophysical scanning data and machine learning (ML) algorithms. This included determining the optimal set of independent variables and the most suitable ML method. Soil parameters such as electrical conductivity, magnetic susceptibility, and soil reflectance in infrared spectra were mapped using data from Geonics EM-38 and Veris 3100 scanners. These data, along with soil texture, served as inputs for predicting fuel consumption and field productivity. Three machine learning algorithms were tested: support vector machines (SVMs), multilayer perceptron (MLP), and radial basis function (RBF) neural networks. Among these, SVM achieved the best performance, showing a MAPE of 4% and a strong correlation (R = 0.97) between predicted and actual productivity values. For fuel consumption, the optimal method was MLP (MAPE = 4% and R = 0.63). The findings demonstrate the viability of geophysical scanning and machine learning for accurately predicting energy use in tillage operations. This approach supports more sustainable agriculture by enabling optimized fuel use and reducing environmental impact through data-driven field management. Further research is needed to obtain training data for different soil parameters and agrotechnical treatments in order to develop more universal models. Full article

In this article, we present a case of a 49-year-old woman presenting with a recurrent metastatic neuroendocrine tumor. Background: Insulinomas are neuroendocrine tumors derived from beta cells of the pancreas that secrete insulin. Usually, they are benign tumors; however, metastatic insulinomas are an extremely rare malignant form of these tumors, carrying a significantly worse prognosis. Case Presentation: A 49-year-old woman, a patient in the University Hospital in Wroclaw in the Department of Endocrinology, Diabetes and Isotope Therapy, first presented with abdominal pain in 2009, when ultrasound and further examination led to the diagnosis of a tumor in the pancreas (a solid pseudopapillary tumor of the pancreas—meta NET G2), and the patient underwent distal pancreatectomy with splenectomy. For ten years, she was under observation, and her symptoms, such as abdominal pain, nausea, weight loss, and general weakness, reappeared in 2019. Then, magnetic resonance imaging (MRI) showed a lesion in the liver, and further histopathology revealed neuroendocrine tumor (NET) metastasis to the liver. In 2022, the patient presented with loss of consciousness and convulsion, loss of weight, and hypoglycemia after meals. In April 2022, the daily glycemic profile was recorded and a 72 h fasting test was performed; however, their results excluded insulinoma. Positron emission tomography–computed tomography (PET-CT) with 18F-fluorodeoxyglucose (18F-FDG) and PET with gallium-68-DOTA-(Tyr3)-octreotate (68Ga-DOTA-TATE) showed a metastatic proliferative process in the liver. Persistent hypoglycemia led to another hospitalization in May 2022, and repeated tests allowed for the diagnosis of insulinoma. Treatment with somatostatin analogs and diazoxide was started. A CT scan in November 2022 and a PET scan in January 2023 showed new metastases to the liver, bones, and cervical lymph nodes, and it was decided to intensify the treatment. In May 2023, the patient was qualified for Lutathera treatment for insulinoma at the University Clinical Hospital in Poznań. In June 2023, another disturbing symptom was reported by the patient, a painful lump in the breast. During diagnostics, metastases with high proliferation markers were found in both breasts. Two months later, in August 2023, the patient received another dose of Lutathera. In October 2023, significant progression of liver lesions, metastases to bones of the spine, ribs, and pelvis, and periaortic and pelvic lymphadenopathy were found as well as elevated values of neuron-specific enolase and calcitonin. The patient was also referred to the Palliative Medicine Home Hospice. In consultation with the Lower Silesian Cancer Center, the decision was made to forgo further treatment with PRRT and initiate systemic chemotherapy. Despite the chosen treatment, the patient died on 27/DEC/2023. Conclusions: This case report can serve clinicians, as it presents a case of an extremely rare and insidious tumor, metastatic insulinoma. Full article

This study presents a detailed investigation of the torque-speed characteristics of a WEG single-phase squirrel-cage induction motor (SPSCIM) of (1/2 hp), 110/220 V at 60 Hz. The primary objective was to derive the motor’s equivalent circuit and validate its performance curves through finite element analysis (FEA), simulation using MATLAB^®/Simulink^®, and experimental testing. Finite element simulations were conducted using the software FEMM (Finite Element Method Magnetics) to model the magnetic flux distribution within the motor’s stator and rotor. These simulations, based on the motor’s dimensions and nameplate data, provided essential insights into the electromagnetic behavior, including flux density and saturation effects, which are crucial for accurate torque-speed curve predictions. For experimental validation, tests were performed under open-circuit and locked-rotor conditions through a universal machine as a load emulator. The torque-speed characteristics were determined using the Suhr method and the classical approach, with the resulting curves compared to experimental measurements. Voltage and current were measured using AC PZEM-004T and DC PZEM-017 meters, while rotor speed was monitored with a Hall effect sensor (A3144). The results revealed strong agreement between the FEM simulations, Surh method, and experimental data, demonstrating the reliability and accuracy of the combined simulation and analytical methods for modeling the motor’s performance. The estimations using classical and Suhr methods, Simulink simulations, and FEMM yielded low error percentages, mostly below 2%. However, in the FEMM simulation, rotor resistance showed a higher error of around 20% due to unavailable data on the exact number of windings turns, a modifiable parameter that can be corrected through further adjustments in the simulation. The torque-speed curves obtained at different voltage levels showed an excellent correlation, confirming the effectiveness of the proposed approach in characterizing the motor’s operational behavior. Full article

The site-directed immobilization of enzymes has demonstrated significant potential in industrial applications due to its ability to minimize enzyme heterogeneity and maximize retained activity. However, existing approaches often require the introduction of unnatural amino acids or excessive specific ligase to achieve this goal. In this study, a self-catalyzed protein capture system (i.e., the SnoopCatcher/SnoopTag pair) was utilized for the directed immobilization of lipase on magnetic carriers. By tagging the Pseudomonas fluorescens lipase (PFL) with a SnoopTag at the C-terminal, the fused lipase PFL-SnoopTag (PSNT) readily conjugated with the SnoopCatcher partner via a spontaneously formed isopeptide bond between them. Novel magnetic particles functionalized by SnoopCatcher proteins were prepared using a co-precipitation method, achieving a loading capacity of around 0.8 mg/g carrier for the SnoopCatcher. This functionalized magnetic carrier enabled the site-directed immobilization of lipase PSNT at 81.4% efficiency, while the enzyme loading capacity reached 3.04 mg/g carriers. To further assess the practical performance of site-directed immobilized lipases, they were applied in biodiesel production and achieved a yield of 88.5%. Our results demonstrate a universal platform for the site-directed immobilization of enzymes with high performance, which offers significant advantages, e.g., single-step purification and catalyst-free immobilization of engineered enzymes, as well as easy recovery, highlighting its potential for industrial applications. Full article