Anomalous Orbital Structures Research Articles

Congenital Monocular Deficit of Elevation and Myopia Case Report

We present a case of congenital restrictive strabismus and axial myopia that was associated with an anomalous orbital structure identified by MRI and CT. This fibrous band was observed and resected during surgery

Strain engineering of epitaxial oxide heterostructures beyond substrate limitations

Strain engineering of epitaxial oxide heterostructures beyond substrate limitations

Mean plane of the Kuiper belt beyond 50 AU in the presence of Planet 9

Context. A recent observational census of Kuiper belt objects (KBOs) has unveiled anomalous orbital structures. This has led to the hypothesis that an additional ∼5 − 10 m⊕ planet exists. This planet, known as Planet 9, occupies an eccentric and inclined orbit at hundreds of astronomical units. However, the KBOs under consideration have the largest known semimajor axes at a > 250 AU; thus they are very difficult to detect. Aims. In the context of the proposed Planet 9, we aim to measure the mean plane of the Kuiper belt at a > 50 AU. In a comparison of the expected and observed mean planes, some constraints would be put on the mass and orbit of this undiscovered planet. Methods. We adopted and developed the theoretical approach of Volk & Malhotra (2017, AJ, 154, 62) to the relative angle δ between the expected mean plane of the Kuiper belt and the invariable plane determined by the eight known planets. Numerical simulations were constructed to validate our theoretical approach. Then similar to Volk & Malhotra (2017, AJ, 154, 62), we derived the angle δ for the real observed KBOs with 100 < a < 200 AU, and the measurement uncertainties were also estimated. Finally, for comparison, maps of the theoretically expected δ were created for different combinations of possible Planet 9 parameters. Results. The expected mean plane of the Kuiper belt nearly coincides with the said invariable plane interior to a = 90 AU. But these two planes deviate noticeably from each other at a > 100 AU owing to the presence of Planet 9 because the relative angle δ could be as large as ∼10°. Using the 1σ upper limit of δ < 5° deduced from real KBO samples as a constraint, we present the most probable parameters of Planet 9: for mass m9 = 10 m⊕, orbits with inclinations i9 = 30°, 20°, and 15° should have semimajor axes a9 > 530 AU, 450 AU, and 400 AU, respectively; for m9 = 5 m⊕, the orbit is i9 = 30° and a9 > 440 AU, or i9 < 20° and a9 > 400 AU. In this work, the minimum a9 increases with the eccentricity e9 (∈[0.2, 0.6]) but not significantly.

An Alternative Model of Rotation Curve that Explains Anomalous Orbital Velocity, Mass Discrepancy and Structure of Some Galaxies

A new model of galaxy rotation based on the cyclostrophic model of vortices found in nature is developed. The model is tested using the SPARC dataset of 175 galaxies and a smaller dataset comprising of 60 galaxies. Analysis of the datasets showed that galactic rotation can be adequately described using the observed surface brightness of galaxies and the newly developed cyclostrophic velocity model. The use of the luminosity and the inverse mass-to-light ratio in lieu of the surface brightness, also yield a very good fit of the observed and computed galaxy rotation velocity. Evidently, galactic rotation greatly depends on the cyclostrophic balance of the pressure gradient and the centrifugal forces and the seismic-induced radial expansion occurring in various stars. This is the most probable origin of the action of a single force law that has been overlooked in previous studies. Therefore, the need for a super-massive black hole at the center of galaxies or hidden dark matter can be eliminated. Attractive gravitational force can occur even without a massive black hole at the center of galaxies. There appears to be a pressure gradient force between the center and the outer parts of galaxies that sustains attraction. The cyclostrophic model appears to be the physical basis of the Tully-Fisher relation. Furthermore, the missing mass problem associated with galactic rotation can be attributed to the orbital expansion of celestial objects perturbed by seismic-induced forces. In addition, massive tremors or starquakes may create a domino effect in perturbing nearby stars along the axis of the seismic-induced force and this could result in the formation of elliptical galaxies as the orbits of seismic-perturbed neighboring stars become larger.

Accessory Extraocular Muscle as a Cause of Restrictive Strabismus

ABSTRACTRestrictive strabismus resulting from the presence of an accessory extraocular muscle has rarely been reported in the literature. Most articles written on this topic are isolated case reports. The purpose of this paper is to describe a series of 7 similar patients presenting with atypical restrictive strabismus associated with enophthalmos in the affected eye, which was found to be caused by an accessory extraocular muscle attached to the posterior globe near the optic nerve. The medical records of 7 patients who shared these clinical characteristics were retrospectively analyzed. Orbital imaging was obtained in the 7 cases, which were compared. Three of the patients were females and four were males. The left eye was affected in all 4 males and the right eye was affected in the 3 females. The 7 patients presented with the following clinical characteristics: enophthalmos, restriction to eye movements in most fields of gaze, and presence of an anomalous orbital structure that was interpreted on magnetic resonance imaging (MRI) to be an accessory extraocular muscle inserting onto the posterior surface of the globe in the affected eye. The fellow eye was normal in all cases. Five of the 7 patients underwent surgical correction with partial improvement in only one patient. The presence of an accessory extraocular muscle should be included in the differential diagnosis of patients with atypical restrictive strabismus. Orbital computed tomography or MRI are essential for correct diagnosis in these cases.

Anomalous orbital structure in a spinel–perovskite interface

AbstractIn all archetypical reported (001)-oriented perovskite heterostructures, it has been deduced that the preferential occupation of two-dimensional electron gases is in-plane dxy state. In sharp contrast to this, the investigated electronic structure of a spinel-perovskite heterostructure γ-Al2O3/SrTiO3 by resonant soft X-ray linear dichroism, demonstrates that the preferential occupation is in out-of-plane dxz/dyz states for interfacial electrons. Moreover, the impact of strain further corroborates that this anomalous orbital structure can be linked to the altered crystal field at the interface and symmetry breaking of the interfacial structural units. Our findings provide another interesting route to engineer emergent quantum states with deterministic orbital symmetry.

Anomalous orbital structures resulting in vertical retraction syndrome

Vertical restraction syndrome is a rare, congenital eye vertical movement disorder characterized by the retraction of the globe and narrowing of the palpebral fissure during downward or upward gaze.

Orbital Causes of Incomitant Strabismus.

Strabismus may result from abnormal innervation, structure, or function of the extraocular muscles. Abnormalities of the orbital bones or masses within the orbit may also cause strabismus due to indirect effects on the extraocular muscles. This paper reviews some disorders of the orbit that are associated with strabismus, including craniofacial malformations, orbital masses, trauma, and anomalous orbital structures.

Atypical Restrictive Strabismus Secondary to an Anomalous Orbital Structure: Differential Diagnosis

Anomalous orbital structures are very rare causes of restrictive strabismus. Of the 3 types described in the literature, one involves accessory muscle fibers that are innervated by the III and/or VI cranial nerves originating in the posterior orbit and inserting on the globe, optic nerve, or extraocular muscles. Although these structures do not cause specific symptoms that enable us to make a diagnosis, we must take them into account in patients with atypical restrictive strabismus. Computed tomography and, particularly, orbital magnetic resonance imaging are essential for correct diagnosis and treatment, as the only other way to diagnose this condition is through casual findings during surgery to correct strabismus. Our patient was a child who were initially diagnosed as Duane syndrome. Magnetic resonance imaging revealed an anomalous unilateral orbital structure that limited all ocular movements except adduction, and possibly contributed to globe retraction. Surgery for strabismus did not resolve the problem: the posterior location of the orbital structure rendered surgery impossible.

Vertical retraction syndrome caused by anomalous orbital structures

To described the clinical feature and MRI imaging of six children with vertical retraction syndrome. Six children with unilateral vertical retraction syndrome between 15 months and 8 years of age, mean age was (5.01 ± 1.27) years old. Strabismus examination included diopter, prism diopters, eye movement examination, binocular vision and fundus examination. Imaging of the ocular motor nerves at the brainstem was performed in 0.8 mm thickness image planes using 3D-FIESTA sequence, the orbits were imaged with FSE T1, T2WI using surface coils, and within 2.0 mm thick planes. Four children showed hypertropia, characterized by limited depression, a light retraction of the globe during downward gaze and eyelid lag. The MRI imaging showed anomalous orbital structure in the superonasal quadrant that between medial rectus and superior rectus or adjacent to the superior rectus. Two children showed intermittent exotropia, characterized by limited elevation, retraction of the globe and narrowing of the palpebral fissure during upward gaze. The MRI imaging showed anomalous orbital structure was present in the inferotemporal quadrant, one originate in inferior rectus and another close to the lateral rectus. Anomalous orbital structures are a main cause of vertical retraction syndrome. The presence of specific unusual eye movement and MRI imaging may assist in diagnosis. When the eyelid lag was found since the early age, anomalous orbital structures were implied.

An anomalous muscle linking superior and inferior rectus muscles in the orbit

Dissections of the bilateral orbits in a 45-year-old female cadaver, who had no ocular movement disorders in her lifetime, revealed anomalous muscles linking the superior and inferior rectus muscles. The muscles, situated between the optic nerve and the lateral rectus muscle, originated from the annulus of Zinn and branched off two heads; one inserted into the medial inferior side of the superior rectus muscle and the other inserted into the central superior side of the inferior rectus muscle. Each insertion was located on a distal site of the myoneural junction of each rectus muscle. Histological investigations showed that the muscles had a striated muscle structure. No definite nerve insertion was observed in the muscles. Although this type of anomalous muscle has been reported in a few Caucasian cases, the present study is the first report in an Asian person. Anomalous orbital structures, which are a rare cause of strabismus, are important in the differential diagnosis of intra-orbital space-occupying lesions, rather than the differential diagnosis of strabismus.

Strabismus Secondary to Adnexal Restrictions

Adnexal restriction due to anomalous orbital structures is a rare cause of strabismus. These anomalous structures include accessory muscles and fibrous bands that insert in abnormal locations on the globe or on the extraocular muscles themselves. They may be present in patients with restrictive strabismus with unusual patterns of motility, including globe retraction not associated with Duane retraction syndrome, very large vertical strabismus, and elevation deficits that are worse in abduction. Imaging studies are useful in the evaluation of such patients. Release of the restrictive orbital structures may improve the strabismus in some patients.