Search Results (1,718)

This paper discusses the application of on-chip terahertz (THz) filters attached to waveguides that can act as sensor elements, including for scanned imaging applications. Our work presents a comparative numerical study of several different geometries (comprising five split-ring resonator geometries and a quarter-wavelength stub resonator, the latter being well established as a sensor at THz frequencies and therefore able to act as a benchmark). We designed each structure to have a resonant frequency of 500 GHz, allowing the impact of resonator geometry on sensing performance to be isolated; the performance was quantified by assessing each design using four figures of merit: resonance quality factor, sensitivity (relative frequency shift under dielectric loading), responsivity (sensitivity weighted by resonance sharpness), and the electric field confinement area. Simulations were conducted using Ansys HFSS using the properties of a commercially available photoresist (Shipley 1813) as a dielectric load to assess performance under conditions comparable to previous experimental studies. The analysis showed that while sensitivity remained broadly similar across geometries, responsivity and quality factor differed substantially between resonators. Furthermore, the spatial distribution of the electric field and current density, particularly in rotated configurations, was found to significantly impact coupling efficiency between the resonator and transmission line. Our findings provide guidance for the general design of systems employing THz sensors while establishing a framework with which to benchmark future sensor geometries. Full article

Microwaves have been used as a heat source in various chemical processes, and their application range is expanding to include high-temperature processes. Existing microwave-based methods for glass syntheses predominantly involve coating and drying. Moreover, microwaves have rarely been applied to glass melting, which consumes a large amount of energy. In this study, the raw materials required for preparing optical glass were heated using microwaves to reduce the energy consumption of the glass-melting process. Microwaves were applied to the raw materials of a typical optical glass, i.e., borosilicate crown glass (BK7). The results indicated that the raw materials rapidly reached the target temperature of 1000 °C and were heated particularly well at temperatures above 500 °C. This was reflected in the high microwave absorption of BK7 above 500 °C, as confirmed by dielectric-constant measurements in the high-temperature range using resonance perturbation. Additionally, BK7 was heated on a 100 g scale in a large microwave-concentrated hexagonal furnace. The obtained glass exhibited a refractive index of 1.5155 (d-line of helium: λ = 587.56 nm), which is comparable to that obtained via conventional heating. Our findings are expected to help reduce the time needed for glass melting considerably and conserve energy, thus contributing to a sustainable society. Full article

Metabolomics, which is typically referred to as the post-genomic methodology addressing low-molecular-weight metabolites, became a powerful tool in post-genomic research over the last two decades. Indeed, the state-of-the-art metabolomics relies on several well-established complementary platforms—nuclear magnetic resonance (NMR) spectroscopy, liquid and gas chromatography coupled on-line with mass spectrometry (LC- and GC-MS, respectively), and capillary electrophoresis–mass spectrometry (CE-MS). Among them, GC-MS represents one of the oldest and most well-established techniques currently employed in the metabolomics of volatile compounds and non-volatiles—polar low-molecular-weight metabolites, which can be efficiently converted in volatile form by comprehensive derivatization of polar functional groups. Currently, GC-MS is established as the principal analytical method for characterizing primary plant metabolism, although other methods also contribute significantly to determining the complete metabolite profile. Therefore, here, we address the role of GC-MS in plant metabolomics and its potential for the profiling of low-molecular-weight metabolites. Further, we comprehensively review the methods of sample preparation with special emphasis on extraction and derivatization approaches, which are currently employed to improve the method performance and its metabolome coverage. Full article

This article explores whether jerk, the derivative of acceleration, should be limited in trajectory planning for position-controlled mechanical systems or in the controller. The excess jerk excites structural resonances and increases actuator wear, motivating the use of a limited jerk. However, we question the necessity of incorporating the jerk directly in trajectory planning by comparing third-order jerk-limited trajectories with second-order trajectories with reduced controller bandwidth that regulate torque gradients. We demonstrate by a typical practical application that reducing controller bandwidth can achieve comparable or superior jerk reduction without extending overall motion time for point-to-point trajectories. As a result, second-order parabolic trajectory profiles simplify on-line implementation. This investigation relies on a detailed sensitivity analysis of a one-dimensional model, incorporating crucial elements such as signal and sensor quantisation, sampling, and modes of structural resonances. The study shows that smooth trajectories reduce resonant vibrations and wear, but the jerk limitation may be addressed more effectively within the controller rather than within the trajectory generator. We conclude that although the limitation of the jerk in the trajectories is valuable, feedback controllers can reduce the jerk more effectively by bandwidth reduction, allowing simpler point-to-point trajectory designs without compromising performance. Full article

Organic field-effect transistors (OFETs) require reliable micro- and nanoscale patterning of semiconducting layers, yet conjugated polymers have long been considered incompatible with photolithography due to dissolution and chemical damage from photoresist solvents. Here, we present a photolithography-compatible strategy based on doping-induced solubility conversion (DISC), demonstrated using poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene] (PBTTT). AuCl₃ doping reversibly modulates the benzoid/quinoid resonance balance, lamellar stacking, and π–π interactions, suppressing solubility during lithographic exposure, while dedoping restores the intrinsic electronic properties. Using this approach, micropatterns with linewidths as small as 2 µm were fabricated in diverse geometries—including line arrays, concentric rings, dot arrays, and curved channels—with high fidelity; quantitative analysis of dot arrays yielded mean absolute errors of 48–66 nm and coefficients of variation of 2.0–3.9%, confirming resolution and reproducibility across large areas. Importantly, OFETs based on patterned PBTTT exhibited charge-carrier mobility, threshold voltage, and on/off ratios comparable to spin-coated devices, despite undergoing multiple photolithography steps, indicating preservation of transport characteristics. Furthermore, the same DISC-assisted lithography was successfully applied to other representative p-type conjugated polymers, including P3HT and PDPP-4T, confirming the universality of the method. This scalable strategy thus combines the precision of established lithography with the functional advantages of organic semiconductors, providing a robust platform for high-density organic electronic integration in flexible circuits, biointerfaces, and active-matrix systems. Full article

Coronary artery bypass grafting (CABG) remains a cornerstone of treatment for patients with advanced or complex coronary artery disease, yet long-term success is influenced by graft patency, progression of native disease, and ventricular remodeling. Optimizing the follow-up of these patients requires a structured approach in which multimodality cardiovascular imaging plays a central role. Echocardiography remains the first-line modality, providing readily available assessment of ventricular function, valvular competence, and wall motion, while advanced techniques, such as strain imaging and myocardial work, enhance sensitivity for subclinical dysfunction. Coronary computed tomography angiography (CCTA) offers excellent diagnostic accuracy for graft patency and native coronary anatomy, with emerging applications of CT perfusion and fractional flow reserve derived from CT (FFR-CT) expanding its ability to assess lesion-specific ischemia. Cardiovascular magnetic resonance (CMR) provides comprehensive tissue characterization, quantifying scar burden, viability, and inducible ischemia, and stress CMR protocols have demonstrated both safety and independent prognostic value in post-CABG cohorts. Nuclear imaging with single-photon emission computed tomography (SPECT) and positron emission tomography (PET) remains essential for quantifying perfusion, viability, and absolute myocardial blood flow, with hybrid PET/CT approaches offering further refinement in patients with recurrent symptoms. In patients after CABG, multimodality imaging is tailored to the patient’s characteristics, symptoms, and pre-test probability of disease progression. In asymptomatic patients, imaging focuses on surveillance, risk stratification, and the early detection of subclinical abnormalities, whereas in symptomatic individuals, it focuses on establishing the diagnosis, defining prognosis, and guiding therapeutic interventions. Therefore, the aim of our review is to propose updated and comprehensive guidance on the crucial role of multimodality cardiovascular imaging in the evaluation and management of post-CABG patients and to provide a practical, evidence-based framework for optimizing outcomes. Full article

Single exosomes are detected via surface-enhanced Raman scattering (SERS) due to electromagnetic field accumulation on a specially designed flexible metasurface. This metasurface is a modulated silver nanofilm deposited on a thin, flexible plastic substrate. An explicit Equation for calculating the local electric field is given. The field reaches extremely high values under plasmon resonance conditions and fills the depressions of the metasurface. The thin, flexible metasurface can be incorporated into automated Lab-On-Chip analytical systems and used for spectroscopic studies of exosomes. We propose a method to distinguish individual exosomes from the HEK293T cell line on the metasurface and then obtain and assign their SERS spectra. An important advantage of the plasmonic metasurface presented in this work is its spatial complementarity to exosomes and other vesicle-like objects. The plasmonic metasurface is fabricated using holographic lithography and further investigated using a correlation approach combining atomic force microscopy, scanning spreading resistance microscopy, and surface-enhanced spectroscopy. Full article

This paper presents a high-sensitivity microwave sensor based on a modified Complementary Split Ring Resonator (CSRR) architecture, integrated with inductive stubs, for non-invasive blood glucose monitoring. The proposed sensor is designed to enhance the electric field localization and coupling efficiency by introducing inductive elements that strengthen the perturbation effect caused by glucose concentration changes in the blood. Numerical simulations were conducted using a multilayer finger model to evaluate the sensor’s performance under various glucose levels ranging from 0 to 500 mg/dL. The modified sensor exhibits dual-resonance characteristics and outperforms the conventional CSRR in both frequency and amplitude sensitivity. At an optimized stub gap of 2 mm, which effectively minimizes the capacitive coupling effect of the transmission line and thereby improves the quality factor, the sensor achieves a frequency shift sensitivity of 0.086 MHz/mg/dL and an amplitude sensitivity of 0.02 dB/mg/dL, compared to 0.032 MHz/mg/dL and 0.0116 dB/mg/dL observed in the standard CSRR structure. This confirms a significant enhancement in sensing performance and field confinement due to the optimized inductive loading. These results represent significant enhancements of approximately 168% and 72%, respectively. With its compact design, increased sensitivity, and potential for wearable implementation, the proposed sensor offers a promising platform for continuous, real-time, and non-invasive glucose monitoring in biomedical applications. Full article

Silver nanoparticles (AgNPs) are widely studied in oncological nanomedicine, although concerns persist regarding their toxicity, elimination, and tissue accumulation. The biological properties of AgNPs depend on the synthesis method and the reducing agent used, which may influence cytotoxicity and cellular metabolism. This study aimed to evaluate the effect of the reducing agent on the cytotoxicity of AgNPs in leukemia (JURKAT) cell lines and peripheral blood mononuclear cells (PBMCs). AgNPs were synthesized via chemical reduction using glucose (GLU) or polyvinylpyrrolidone (PVP) as reducing agents. Nanoparticles were characterized by UV-Vis, FTIR, DLS, zeta potential, and TEM. Cell viability was assessed using trypan blue exclusion, and cytotoxicity was determined using the MTT assay. UV-Vis analysis showed distinct surface plasmon resonance profiles, and FTIR confirmed characteristic functional groups on the nanoparticle surface. DLS and zeta potential values indicated colloidal stability, with PVP-AgNPs presenting a more negative surface charge. TEM revealed greater size heterogeneity in GLU-AgNPs. GLU-AgNPs induced lower cytotoxicity and higher cell viability in JURKAT and PBMCs compared to PVP-AgNPs (p < 0.05). Leukemia cells were more susceptible to both nanoparticle types than PBMCs, showing a favorable selectivity index for GLU-AgNPs (SI = 2.44). These findings suggest that biocompatible reducing agents may improve the safety profile of AgNPs. Full article

The liquid crystal (LC) poly-γ-benzyl-L-glutamate (PBLG) is known to possess a narrow biphasic range at the phase transition from an isotropic liquid to an anisotropic liquid crystal. We have characterized the biphasic region via deuterium nuclear magnetic resonance (NMR) of the deuterated solvent CDCl₃, with which isotropic and anisotropic populations can unambiguously be identified and quantified due to the quadrupolar coupling induced by partial alignment. In addition to a dilution series, we measured the kinetics of the alignment inside the magnet for each dilution step and were able to follow the kinetic buildup of partial alignment. Beginning with the dynamic line broadening indicative of slow fluctuations, to microheterogeneous patches of isotropic and anisotropic islands, with increasing island size being consistent with sharpened spectra, ending in fully separated isotropic and anisotropic phases on top of each other after two weeks. In addition, we studied the influence of the two example guest molecules borneol and camphor—which essentially differ in their capability to act as hydrogen bond donors or acceptors—on the biphasic region of PBLG. Full article

Background and Clinical Significance: Adults suffering from cerebellar metastases are often at high risk for rapid deterioration of their neurological status because the posterior fossa has limited compliance and the location of these metastases are close to the brain stem and important cerebrospinal fluid (CSF) pathways. In this paper, we present a longitudinal, patient-centered report on the history of an elderly individual who suffered from cognitive comorbidities and experienced a sudden loss of function in her cerebellum. Our goal in reporting this case is to provide a comparison between the patient’s pre-operative and post-operative neurological examinations; the imaging studies she had before and after surgery; the surgical techniques utilized during her operation; and the outcome of her post-operative course in a way that will be helpful to other patients who have experienced a similar situation. Case Presentation: We report the case of an 80-year-old woman who initially presented with progressive ipsilateral limb-trunk ataxia, impaired smooth pursuit eye movement, and rebound nystagmus, but preserved pyramidal and sensory functions. Her quantitative bedside assessments included some of the components of the Scale for the Assessment and Rating of Ataxia (SARA), and a National Institute of Health Stroke Scale (NIHSS) score of 3. These findings indicated dysfunction of the left neocerebellar hemisphere and possible dentate nucleus involvement. The patient’s magnetic resonance imaging (MRI) results demonstrated an expansive mass with surrounding vasogenic edema and marked compression and narrowing of the exits of the fourth ventricle which placed the patient’s CSF pathways at significant risk of occlusion, while the aqueduct and inlets were patent. She then underwent a left lateral suboccipital craniectomy with controlled arachnoidal CSF release, preservation of venous drainage routes, subpial corticotomy oriented along the lines of the folia, stepwise internal debulking, and careful protection of the cerebellar peduncles and dentate nucleus. Dural reconstruction utilized a watertight pericranial graft to restore the cisternal compartments. Her post-operative intensive care unit (ICU) management emphasized optimal venous outflow, normoventilation, and early mobilization. Histopathology confirmed the presence of metastatic carcinoma, and staging suggested that the most likely source of the primary tumor was the lungs. Immediately post-operation, computed tomography (CT) imaging revealed a smooth resection cavity with open foramina of Magendie and Luschka, intact contours of the brain stem, and no evidence of bleeding or hydrocephalus. The patient’s neurological deficits, including dysmetria, scanning dysarthria, and ataxic gait, improved gradually during the first 48 h post-operatively. Upon discharge, the patient demonstrated an improvement in her limb-kinetic subscore on the International Cooperative Ataxia Rating Scale (ICARS) and demonstrated independent ambulation. At two weeks post-operation, CT imaging revealed decreasing edema and stable cavity size, and the patient’s modified Rankin scale had improved from 3 upon admission to 1. There were no episodes of CSF leakage, wound complications, or new cranial nerve deficits. A transient post-operative psychotic episode that was likely secondary to her underlying Alzheimer’s disease was managed successfully with short-course pharmacotherapy. Conclusions: The current case study demonstrates the value of anatomy-based microsurgical planning, preservation of venous and CSF pathways, and targeted peri-operative management to facilitate rapid recovery of function in older adults who suffer from cerebellar metastasis and cognitive comorbidities. The case also demonstrates the importance of early multidisciplinary collaboration to allow for timely initiation of both adjuvant stereotactic radiosurgery and molecularly informed systemic therapy. Full article

This paper proposes a single-phase AC-AC solid-state transformer (SST) that eliminates bulky energy storage components. The proposed matrix-type structure comprises a line-frequency (LF) rectifier, a half-bridge (HB) LLC resonant converter, a buck–boost converter, and an LF inverter. The HB LLC resonant converter not only achieves high efficiency at unity voltage gain but also provides high-frequency (HF) isolation as a DC transformer (DCX). Meanwhile, the buck–boost converter ensures precise voltage regulation. The replacement of traditional DC-link electrolytic capacitors with small film capacitors effectively suppresses the second-harmonic power ripple, leading to a significant improvement in both power density and operational reliability. Experimental results from a 1 kW prototype demonstrate high-quality sinusoidal input and output, a wide range of zero-voltage switching (ZVS) operations, and stable output voltage control. Full article

Magnetosomes are organelle-like structures within magnetotactic bacteria that store iron biominerals in membrane-bound vesicles. In bacteria, formation of these structures is highly regulated by approximately 30 genes, which are conserved throughout different species. To compartmentalize iron in mammalian cells and provide gene-based contrast for magnetic resonance imaging, we introduced key magnetosome proteins. The expression of essential magnetosome genes mamI and mamL as fluorescent fusion proteins in a human melanoma cell line confirmed their co-localization and interaction. Here, we investigate the expression of two more essential magnetosome genes, mamB and mamE, using confocal microscopy to describe fluorescent fusion protein expression patterns and analyze the observed intracellular mobility. Custom software was developed to characterize fluorescent particle trajectories. In mammalian cells, essential magnetosome proteins display different diffusive behaviours. However, all magnetosome proteins travelled at similar velocities when interacting with mammalian mobile elements, suggesting that MamL, MamL + MamI, MamB, and MamE interact with similar molecular motor proteins. These results confirm that localization and interaction of essential magnetosome proteins are feasible within the mammalian intracellular compartment. Full article

We demonstrate a compact astro-comb with ~30 GHz line spacing covering the 560–900 nm range, seeded by a 1 GHz Yb:fiber laser frequency comb phase-locked to a rubidium clock for long-term frequency stability. The comb spacing is multiplied by a passively stabilized Fabry–Pérot cavity, which is vacuum-sealed (3.3 × 10⁻⁵ Pa) and temperature-controlled at 25 ± 0.05 °C, exhibiting a resonance linewidth of 80.56 MHz. Characterization using a high-resolution Fourier-transform spectrometer reveals sharp, evenly spaced comb lines with a maximum side-mode suppression ratio of 23.86 dB. The estimated radial velocity (RV) precision reaches ~63 cm/s, and further reduction in measurement noise is expected to achieve <10 cm/s precision, meeting the stringent requirements of next-generation astronomical spectrographs. Full article

Apical hypertrophic cardiomyopathy is a distinctive and often under-recognized variant of hypertrophic cardiomyopathy, characterized by predominant thickening of the apical segments of the left ventricle. Echocardiography and cardiac magnetic resonance imaging represent the two principal modalities for diagnosis and morphological assessment. While transthoracic echocardiography remains the first-line imaging technique, it may underestimate apical involvement, particularly when image foreshortening or poor endocardial/epicardial delineation occurs. Cardiac magnetic resonance has become the reference standard for defining apical morphology, quantifying hypertrophy, and characterizing myocardial tissue and perfusion. Beyond its diagnostic role, magnetic resonance serves as a research platform for the identification of new apical-centric criteria which, after appropriate validation, may be translated into echocardiographic practice. Echocardiography, however, retains unique strengths through its real-time evaluation of cardiac dynamics, ready-to-use approach to diastolic function assessment, and its ability to identify subtle apical or para-apical obstructive gradients that may raise the initial diagnostic suspicion. This review underscores the complementary roles of the two modalities and the multiple domains in which transthoracic echocardiography can derive substantial methodological and conceptual benefit from cardiac magnetic resonance imaging, both in imaging methodology and in the refinement of diagnostic evaluation. Full article