Search Results (297)

Orbital floor fractures may cause long-term functional and esthetic impairments. Diplopia due to impaired function of the inferior rectus muscle is frequently an indication for surgical repair, but some cases, such as those where the diagnosis has been delayed or a previous attempt at repair has been made, may not always be amenable to surgical correction. It is advantageous for the surgeon to know whether the proper function of the inferior rectus muscle can be restored for the purposes of surgical planning and prognostication. The authors hypothesized that real-time MRI could be used to characterize the appearance of the inferior rectus muscle in a way that would facilitate future analysis of inferior rectus function in patients with diplopia due to orbital floor fractures. Real-time MRI was performed on 10 volunteer participants with normal ophthalmic function and orbital anatomy to assess inferior rectus appearance during vertical duction testing. ImageJ software was used to measure and record characteristics of the inferior rectus muscle, viewed in a quasi-sagittal plane. The ratios evaluated included inferior rectus muscle length in upgaze versus downgaze (UDR, mean 1.58) as well as inferior rectus muscle length versus distance from inferior rectus origin to inferior rectus inflection point in upgaze (LIR, mean 1.30) and downgaze (mean 1.20). These values were found to be conserved between orbits and individuals. This data offers quantitative insight regarding inferior rectus muscle appearance across the full arc of vertical gaze in healthy individuals. We plan to use this normative baseline dataset as a comparison for future phases of this project, using real-time MRI to evaluate traumatized orbits with diplopia and derangement of the inferior rectus muscle. Full article

Using the Multiconfiguration Dirac–Hartree–Fock method as implemented in the General Relativistic Atomic Structure Package, the magnetic dipole and electric quadrupole hyperfine structure constants were determined for the ground and first excited levels of ^135,137Ba II isotopes, as well as for ¹³⁷Ba I and ⁸⁷Sr II, to assess the robustness of the developed model. This study builds upon and extends previous investigations by examining the levels involved in resonance lines, with the aim of resolving persistent discrepancies in the hyperfine structure of ¹³⁷Ba II and ⁸⁷Sr II. New code developments such as the use of natural orbitals, as well as the addition of polarization effects and Configuration State Function Generators, as implemented in GRASPG, were tested for these heavy elements. The developed strategy allowed us to achieve encouraging results that satisfactorily agree with experiments for all studied levels but ${}^{2}D_{5/2}$ in the ¹³⁷Ba II isotope. This disagreement was also observed in ¹³⁵Ba II isotope as well as in ⁸⁷Sr II. With two valence electrons, ¹³⁷Ba I is definitely more complex, requiring a multireference approach. Even with the latter, the theory–observation disagreement observed for the hyperfine structure of the low-lying levels remains large in comparison with the alkali-like systems. Possible ongoing developments to remediate this issue are discussed in the conclusions. Full article

The photonic spin Hall effect (PSHE) originates from the spin–orbit interaction (SOI) of light. The literature indicates that the transverse spin-dependent shift, ${\delta }_H^{-}$ (SDS), from the PSHE is weak (in the nanometer range) and difficult to measure directly. This study utilizes a plasmonic structure to improve the ${\delta }_H^{-}$ in the PSHE. The obtained results of this study demonstrate that the inclusion of silicon nitride (Si₃N₄) significantly enhances the ${\delta }_H^{-}$ relative to its absence; however, plasmonic material is present in both cases. The enhanced shifts exhibit a significant dependence on the resonance angle (${\theta }_r$) and the thickness of layers of the PSHE structure to attain the maximum increase in ${\delta }_H^{-}$ of 350.82 µm at the plasmonic resonance condition. A systematic analysis of the centroid positions of the reflected beam indicates a distinct and constant separation of opposing spin components. Further, the improved ${\delta }_H^{-}$ is utilized in cancer cell detection, as changes in the refractive index (RI) of cells facilitate the identification of cancer cells from healthy to cancerous. All examined cell types demonstrate that cancerous cells had a greater ${\delta }_H^{-}$ than normal cells, owing to their elevated effective RI. These results illustrate that the proposed plasmonic-assisted PSHE structure offers significant enhancement and a high sensitivity of 439.30 µm/RIU for label-free detection of cancer cells. Full article

We investigate the linear and nonlinear optical properties of (sub-nm) Ag₆ and Au₆ clusters doped with Sc and Y using time-dependent density functional theory. Both parent clusters have D_3h ground-state geometries but exhibit noticeably different electronic structures; scalar-relativistic corrections in Au₆ induce significant s-d hybridization, resulting in larger HOMO-LUMO gaps and reduced one-photon absorption (OPA) cross-sections compared to Ag₆. Two-photon absorption (TPA) peaks in the UV region show resonance enhancement via coupling with OPA-active states, with Ag₆ having larger cross-sections than Au₆. Doping with Sc and Y modifies the optical responses by breaking configurational symmetry and lifting HOMO degeneracies. ScAg₅ and YAg₅ energetically prefer planar configurations with higher dopant orbital contributions, while ScAu₅ and YAu₅ prefer non-planar configurations. This leads to blue-shifted, intensified OPA transitions and larger TPA cross-sections in doped clusters than in parent clusters. Doped Ag clusters exhibit a significantly stronger TPA response in the biologically relevant 1.8–2.0 eV (620–690 nm) spectral region for in vivo imaging. Furthermore, a higher degree of Sc(Y)-Au hybridization generates additional TPA pathways and also facilitates electronic transitions at 1064 nm, enhancing the first hyperpolarizability (β (−2ω; ω, ω)) for YAu₅. Overall, the results show that these (sub-nm) Sc/Y-doped noble metal clusters are promising candidates for photonic and biomedical imaging applications. Full article

Interfacial coupling between CoFe₂O₄ (CFO) nanoparticles and oxidatively functionalized multi-walled carbon nanotubes (MWCNTs) enables controlled modulation of structural, optical, and spin dynamic properties in CFO–MWCNT nanocomposites. The solvothermal synthesis promotes nucleation of CFO on –COOH/–OH functional groups, ensuring uniform anchoring along the nanotube surface. X-ray diffraction confirms a cubic spinel phase with lattice expansion from 8.385 Å to 8.410 Å and crystallite growth from 18 nm to 25 nm, reflecting strain transfer and partial nanoparticle coalescence at the carbon interface. The observed bandgap narrowing from 2.72 eV to 2.50 eV, confirmed via Tauc plot analysis, is attributed to localized defect states induced by charge delocalization and orbital hybridization at the interface of the CFO–MWCNT boundary. DC magnetometry reveals a reduction in saturation magnetization from 46 emu/g to 35 emu/g due to diamagnetic dilution and interfacial spin canting, while coercivity decreases from 852 Oe to 841 Oe, indicating modified pinning and domain-wall dynamics associated with exchange-coupled interfaces. Ferromagnetic resonance measurements show a resonance field shift from 3495 G to 3500 G and an increase in the Landé g-factor from 1.97 to 2.00, signifying altered spin–orbit coupling and enhanced local magnetic perturbations. The spin–lattice relaxation time increases from 1.41 ns to 1.59 ns, demonstrating suppressed phonon-mediated relaxation and improved spin coherence across the hybrid network. Spin density rises from 3.72 × 10²² to 4.58 × 10²² spins/g, confirming an increase in unpaired electrons generated by orbital asymmetry at the interface. The anisotropy field and effective magnetocrystalline anisotropy constant exhibit pronounced modulation, evidencing strengthened exchange stiffness and altered Co²⁺/Fe³⁺ superexchange pathways. These results establish CFO-MWCNT nanocomposites as tuneable platforms for spintronic logic elements, high-frequency microwave attenuation, and magneto-optical device architectures. Full article

Cuprates currently hold the record for the highest temperature superconductivity at ambient pressure, but the microscopic understanding of these materials remains elusive. Here, we utilize nuclear magnetic resonance (NMR) data of planar oxygen and copper from essentially all hole-doped cuprates to provide a universal phenomenology relating the NMR spin shifts, which measure the electronic spin polarization at a given nucleus, with the superconducting dome and maximum critical temperature. There appear to be two separate contributions to the spin shift in planar copper, only one of which is seen at the oxygen site, and we associate them with two different types of carriers. Upon disentangling these two components, their relative size is shown to correlate not only with the doping dependence of the superconducting dome but also with the variation in maximum superconducting critical temperature, $T_{\mathrm{c},\max }$, between different families. One of these components is independent of family and resides in the hybridized planar orbitals of Cu and O. The second component, in contrast, is predominately isotropic and encodes the differences between the families. It is thus related to the charge transfer gap and planar hole sharing. Our findings offer universal insight which should prove useful in the continuing development of a comprehensive theory of the cuprates, as well as an indication of how it may be possible to engineer materials with higher critical temperatures. Full article

Baroclinic wave resonance, particularly Rossby waves, has attracted great interest in ocean and atmospheric physics since the 1970s. Research on Rossby wave resonance covers a wide variety of phenomena that can be unified when focusing on quasi-stationary Rossby waves traveling at the interface of two stratified fluids. This assumes a clear differentiation of the pycnocline, where the density varies strongly vertically. In the atmosphere, such stationary Rossby waves are observable at the tropopause, at the interface between the polar jet and the ascending air column at the meeting of the polar and Ferrel cell circulation, or between the subtropical jet and the descending air column at the meeting of the Ferrel and Hadley cell circulation. The movement of these air columns varies according to the declination of the sun. In oceans, quasi-stationary Rossby waves are observable in the tropics, at mid-latitudes, and around the subtropical gyres (i.e., the gyral Rossby waves GRWs) due to the buoyant properties of warm waters originating from tropical oceans, transported to high latitudes by western boundary currents. The thermocline oscillation results from solar irradiance variations induced by the sun’s declination, as well as solar and orbital cycles. It is governed by the forced, linear, inviscid shallow water equations on the β-plane (or β-cone for GRWs), namely the momentum, continuity, and potential vorticity equations. The coupling of multi-frequency wave systems occurs in exchange zones. The quasi-stationary Rossby waves and the associated zonal/polar and meridional/radial geostrophic currents modify the geostrophy of the basin. Here, it is shown that the ubiquity of resonant forcing in (sub)harmonic modes of Rossby waves in stratified media results from two properties: (1) the natural period of Rossby wave systems tunes to the forcing period, (2) the restoring forces between the different multi-frequency Rossby waves assimilated to inertial Caldirola–Kanai (CK) oscillators are all the stronger when the imbalance between the Coriolis force and the horizontal pressure gradients in the exchange zones is significant. According to the CK equations, this resonance mode ensures the sustainability of the wave systems despite the variability of the forcing periods. The resonant forcing of quasi-stationary Rossby waves is at the origin of climate variations, as well-known as El Niño, glacial–interglacial cycles or extreme events generated by cold drops or, conversely, heat waves. This approach attempts to provide some new avenues for addressing climate and weather issues. Full article

Inspired by the well-known experimental connections between $X\left(3872\right)$, $Z_{cs}\left(4220\right)$, and $Y\left(4620\right)$, we systematically study the recently reported strange partner of $T_{cc}$, the $1^{+}$$cc\overline{q}\overline{s}$ system, and its orbital excitation state $1^{-}$$cc\overline{q}\overline{s}$. A chiral quark model incorporating SU(3) symmetry is considered to study these two systems. To better investigate their spatial structure, we introduce a precise few-body calculation method, the Gaussian Expansion Method (GEM). In our calculations, we include all possible physical channels, including molecular states and diquark structures, and consider channel coupling effects. To identify the stable structures in the system (bound states and resonance states) we employ a powerful resonance search method, the Real-Scaling Method (RSM). According to our results, in the $1^{+}$$cc\overline{q}\overline{s}$ system, we obtain two bound states with energies of 3890 MeV and 3940 MeV, as well as two resonance states with energies of 3975 MeV and 4090 MeV. The decay channels of these two resonance states are $D{D}_s^{\ast }$ and $D^{\ast }{D}_s$, respectively. In the $1^{-}$$cc\overline{q}\overline{s}$ system, we obtain only one resonance state, with an energy of 4570 MeV, and two main decay channels: $D{D}_{s1}^{\ast }$ and $D^{\ast }{D}_{s1}^{\prime }$. We strongly suggest that experimental groups use our predictions to search for these stable structures. Full article

During orbital service, precision aerospace equipment is frequently subjected to harsh vibration environments that can significantly affect reliability and service life. Consequently, the development of effective vibration isolation technologies has become a crucial aspect of aerospace structural design. In this study, random vibration theory and frequency-domain analysis methods were employed to investigate the dynamic response characteristics of a symmetrical frustum-shaped metal rubber (FSMR) isolation device under complex operating conditions. The influence of metal rubber density, spring stiffness, and input vibration level on its isolation performance was systematically examined. This work presents the first systematic experimental investigation into the nonlinear dependencies of the performance of a symmetrical frustum-shaped metal rubber isolator on multiple parameters (density, stiffness, excitation level) under random vibration. The test results show that under identical excitation conditions, the device achieves optimal damping ratio and isolation efficiency (59.71%) when the metal rubber density is 2.0 g/cm³. A moderate increase in spring stiffness reduces the resonance peak and improves stability, with a stiffness of 100 kN/m exhibiting the best overall performance. In addition, higher input vibration levels markedly elevate the acceleration response and the resonant peak amplification factor of the isolator, demonstrating that high-intensity excitation magnifies the vibration response and degrades the isolation efficiency. Full article

Background/Objectives: Thyroid eye disease (TED) can lead to structural and microvascular changes in the orbit and retina. This study aimed to investigate the associations between Clinical Activity Score (CAS), orbital magnetic resonance imaging (MRI) measurements, and retinal microvascular changes in TED patients. Methods: This cross-sectional study included 38 patients (76 eyes) with TED. Each patient underwent a comprehensive ophthalmological evaluation, CAS assessment, and a detailed medical history. Optical coherence tomography angiography (OCTA) was performed to quantify vessel density (VD) in the superficial and deep capillary plexus (SCP and DCP). Exophthalmos, extraocular muscle thickness and orbital fat thickness were measured on MRI scans to evaluate structural changes. Laboratory analyses included thyroid hormone levels, thyrotropin receptor antibodies (TRAb), anti-thyroid peroxidase antibodies (anti-TPO), and lipid profile. Results: Active TED patients (CAS ≥ 3) had significantly higher TRAb levels (p < 0.001), while anti-TPO did not differ between groups. Active eyes showed significantly higher DCP VD in the whole image (p = 0.013), parafovea (p = 0.012), and perifovea (p = 0.009) across all quadrants, with no difference in SCP or the foveal avascular zone (FAZ). In linear mixed model regression analyses, after adjusting for previous glucocorticosteroid therapy, higher triglycerides, greater medial rectus thickness, and whole-image DCP VD independently predicted higher CAS values (R² = 42, p < 0.001). After adjusting for age and sex, CAS remained significantly positive predictor of DCP VD in the parafovea (R² = 0.22, p < 0.001). Conclusions: Changes in DCP VD reflect TED activity and structural orbital involvement. Full article

Grand-design spiral structures typically emerge in N-body simulations of disk galaxies as barred-spiral configurations forming during the early evolutionary stages of the system. In this study, we explore the dynamical conditions that allow for the formation and sustained presence of a non-barred, bisymmetric grand-design spiral pattern in fully self-consistent N-body models over considerable time periods. We present a model in which such non-barred morphologies persist for approximately 2.5 Gyr. The simulation is carried out using a standard implementation of the GADGET-3 code, incorporating both stellar and gaseous components in the disk and embedding them within a live dark matter halo. A characteristic feature of the simulation is that during its normal spiral grand-design phase the disk remains submaximal. Star formation is active throughout the model’s evolution. Analysis of the resulting morphology indicates that dominant inner, symmetric spiral arms extend between the inner Lindblad resonance (ILR) and the radial inner 4:1 resonance. This structure is evident in both the stellar and gaseous components, exhibiting extensions and bifurcations consistent with predictions from orbital theory. Full article

We present a case report of invasive fungal infection in an immunocompromised host, which required a multidisciplinary approach. Mucormycosis is a mold infection caused by a fungi belonging to the order Mucorales. Various forms of the disease have been described, and rhino-orbital-cerebral infection is the most common manifestation. Diabetes, corticosteroid use, malignancy, and a recent history of COVID-19 are well-established immunosuppressive factors that predispose individuals to mucormycosis. Our patient was a forty-five-year-old man with chronic pancreatitis and untreated diabetes mellitus. He presented with sinusitis extending into the right orbit and complicated by central retinal artery occlusion. On admission, the patient complained of three weeks of right-sided headache and eye pain followed by sudden vision loss. He was in good general condition, was alert, oriented, and afebrile. Endoscopic examination revealed the nasal cavity completely filled with pathological tissue displaying fungal morphology. Computed tomography and magnetic resonance imaging revealed a massive orbit infiltration with extraocular muscles and optic nerve invasion. The patient underwent urgent endoscopic debridement. Histopathological examination of the specimens confirmed fungal infiltration. Significant growth of Rhizopus arrhizus was obtained from tissue samples. The surgical procedure was followed by a prolonged antifungal therapy with intensive diabetes management. Full article

Spin–orbit interaction enables the generation and manipulation of spin currents without external magnetic fields, providing opportunities for spin–orbitronic devices. Here, we theoretically investigate a two-dimensional Rashba channel embedded in a Hall geometry with ferromagnetic probes. We demonstrate that symmetry breaking in this configuration leads to experimentally accessible electrical signals, such as open-circuit voltages and short-circuit currents. By analyzing the mirror symmetry of the system, we identified the FM magnetization configurations that maximize these signals. These signals arise from two distinct mechanisms: the Edelstein spin density and spin interference generated by multiple reflections at the Rashba–ferromagnet interfaces. Importantly, the interference is governed solely by the spin-precessional phase, with orbital contributions canceled out. By tuning the channel width, the interference produces Fabry–Perot resonances that allow controllable enhancement of these electrical signals. The resulting Hall responses is well within the range of experimentally reported spin Hall angles, confirming their experimental feasibility. Our results highlight how coherent spin interference, combined with the Edelstein effect, provides a controllable pathway for spin current engineering. Full article

The rapid expansion of Low Earth Orbit (LEO) satellite constellations necessitates the development of multi-band antennas that are not only high-performing but also low-cost, lightweight, and highly reliable for mass production. This paper addresses this need by proposing a novel shared-aperture reflectarray antenna for simultaneous S-band and X-band operation. The design is based on a single-layer architecture that co-integrates two electromagnetically distinct resonant elements—a cross-dipole for the S-band and a diamond-ring slotted patch for the X-band—onto a single 1.52 mm thick Rogers RO3003 substrate. This approach achieves a high frequency ratio of 4:1 while ensuring independent phase control and high isolation for each band through an optimized geometry, circumventing the complexity and reliability issues of conventional multilayer systems. A prototype with dimensions of 260 × 364 mm² was fabricated and experimentally validated in an anechoic chamber. It achieved a measured peak gain of 7.99 dBi at 1.996 GHz for the S-band and 17.99 dBi at 7.94 GHz for the X-band, respectively. The results confirm the viability of the proposed design, demonstrating a structurally simple, easily manufacturable, and cost-effective alternative to complex multilayer systems, making it a promising candidate for next-generation LEO satellite communication platforms. Full article

We investigate the effect of general relativity on the Sitnikov problem. The Sitnikov problem is one of the simplest three-body problems, in which the two primary bodies (a binary system) have equal mass m and orbit their barycenter, while the third body is treated as a test particle under Newtonian gravity. The trajectory of the test particle is perpendicular to the orbital plane of the binary (along z-axis) and passes through the barycenter of the two primaries. To study the general relativistic contributions, we first derive the equations of motion for both the binary and the test particle based on the first post-Newtonian Einstein–Infeld–Hoffmann equation, and integrate these equations numerically. We examine the behavior of the test particle (third body) as a function of the orbital eccentricity of the central binary e, the dimensionless gravitational radius $\lambda$, which characterizes the strength of general relativistic effect, and the initial position of the test particle ${\overline{z}}_0$. Our numerical calculations reveal the following; as general relativistic effects $\lambda$ increase and the eccentricity e of the binary orbit grows, the distance $\overline{r}$ between the test particle and the primary star undergoes complicated oscillations over time. Consequently, the gravitational force acting on the test particle also varies in a complex manner. This leads to a resonance state between the position $\overline{z}$ of the test particle and the distance $\overline{r}$, causing the energy E of the test particle to become $E\ge 0$. This triggers the effective ejection of the test particle due to the gravitational slingshot effect. In this paper, we shall refer to this ejection mechanism of test particle as the “Sitnikov mechanism.” As a concrete phenomenon that becomes noticeable, the increase in general relativistic effects and the eccentricity of the binary orbit leads to the following: (a) ejection of test particles from the system in a shorter time, and (b) increasing escape velocity of the test particle from the system. As an astrophysical application, we point out that the high-velocity ejection of test particles induced by the Sitnikov mechanism could contribute to elucidating the formation processes of astrophysical jets and hyper-velocity stars. Full article