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29,583 result(s) for "Orbitals"
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Susceptibility of severe COVID-19 patients to rhino-orbital mucormycosis fungal infection in different clinical manifestations
Purpose To present the different clinical manifestations of rhino-orbital mucormycosis (ROM) co-infection in severe COVID-19 patients. Study design Prospective observational clinical study Methods Among 32,814 patients hospitalized with the diagnosis of COVID-19 between March 2020 and December 2020 in our center, eleven microbiologically confirmed ROM co-infection cases in severe COVID-19 patients were evaluated. Results There were nine men and two women with a mean age of 73.1 ± 7.7 years. Eight patients had uncontrolled type 2 diabetes with a mean diagnosis duration of 12.1 ± 4.4 years. All patients had COVID-19-associated acute respiratory distress syndrome and received corticosteroids. The mean time interval between COVID-19 diagnosis and ROM diagnosis was 14.4 ± 4.3 days. Seven patients (63.6%) had orbital apex syndrome, and four patients (36.4%) presented with orbital cellulitis. Endophthalmitis was detected in 54.5% of patients, and two of these patients developed retinoschisis. CT scan/MRI revealed sino-orbital involvement in all patients, and three of these had cerebral involvement at initial presentation. All patients received intravenous and retrobulbar liposomal amphotericin B and had undergone radical debridement of involved sinuses. Intravitreal liposomal amphotericin B injected in patients with endophthalmitis. Despite all measures, 63.6% of patients expired. Conclusions Severe COVID-19 is associated with a significant incidence of ROM with higher mortality rates due to immune dysregulation and the widespread use of steroids. Physicians should be aware of the possibility of this infection in patients with COVID-19. An aggressive multidisciplinary approach can help to reduce mortality.
Clinicoradiologic characteristics and management of orbital incidentaloma
To investigate the clinical and radiologic characteristics, treatment outcomes, and management strategies for orbital incidentalomas. We retrospectively reviewed 43 patients with orbital tumors incidentally identified through imaging conducted for unrelated reasons between March 2015 and July 2023. Data on imaging indications, clinicoradiologic features, diagnoses, treatments, and outcomes were analyzed. Patients were divided into surgery ( n  = 14, 32.6%) and observation ( n  = 29, 67.4%) groups for comparison. Among the 43 cases, 20 patients (46.5%) were male, with a mean age of 57.1 years and a mean follow-up of 2.77 years. Initial imaging was most commonly conducted for health check-ups (48.8%), headaches (27.9%), or dizziness (14.0%). Common clinical signs included proptosis (41.9%), peripheral diplopia (21.4%), and hypoglobus (9.3%). Benign lesions, such as cavernous venous malformations (55.8%) and schwannomas (27.9%), predominated, with one case of lymphoma. The surgery group more frequently exhibited clinical signs and anterior tumor locations (71.4% vs. 13.8%, p  = 0.001). Surgical excision was successful without complications. In the observation group, tumor stability was noted in 96.6% without functional deficits. Orbital incidentalomas are often benign and asymptomatic. Observation is recommended for asymptomatic posterior orbital lesions, while surgical removal is indicated for anterior lesions with significant clinical signs.
The impact of polydioxanone (PDS) foil thickness on reconstruction of the orbital geometry after isolated orbital floor fractures
Purpose The orbital floor is frequently involved in head trauma. Current evidence on the use of reconstruction materials for orbital floor repair is inconclusive. Accordingly, this study aimed to compare the impact of polydioxanone (PDS) foil thickness on reconstruction of the orbital geometry after isolated orbital floor fractures. Methods Standardized isolated orbital floor fractures were symmetrically created in 11 cadaver heads that provided 22 orbits. PDS foils with thicknesses of 0.25–0.5 mm were inserted. Computed tomography (CT) scans of the native, fractured, and reconstructed orbits were obtained, and orbital volume, orbital height, and foil bending were measured. Results Orbital volume and height significantly ( p  < 0.01) increased after the creation of isolated orbital floor fractures and significantly ( p  = 0.001) decreased with overcorrection of the orbital geometry after orbital floor reconstruction with PDS 0.25 mm or PDS 0.5 mm. The orbital geometry reconstruction rate did not differ significantly with respect to foil thickness. However, compared to PDS 0.5 mm, the use of PDS 0.25 mm resulted in quantitatively higher reconstructive accuracy and a restored orbital volume that did not significantly differ from the initial volume. Conclusion Orbital floors subjected to isolated fractures were successfully reconstructed using PDS regardless of foil thickness, with overcorrection of the orbital geometry. Due to its lower flexural stiffness, PDS 0.25 mm appeared to provide more accurate orbital geometry reconstruction than PDS 0.5 mm, although no significant difference in reconstructive accuracy between PDS 0.25 mm and PDS 0.5 mm was observed in this cadaveric study.
Orbital angular momentum of Bloch electrons: equilibrium formulation, magneto-electric phenomena, and the orbital Hall effect
The investigation of orbital angular momentum (OAM) of delocalised Bloch electrons has advanced our understanding of magnetic, transport, and optical phenomena in crystals, drawing widespread interest across various materials science domains, from metals and semiconductors to topological and magnetic materials. Here, we review OAM dynamics in depth, focusing on key concepts and non-equilibrium systems, and laying the groundwork for the thriving field of orbitronics. We review briefly the conventional understanding of the equilibrium OAM based on the modern theory of orbital magnetisation. Following this, we explore recent theoretical and experimental developments in out-of-equilibrium systems. We focus on the generation of an OAM density via the orbital magneto-electric, or Edelstein effect, the generation of an OAM current via the orbital Hall effect, the orbital torque resulting from them, along with their reciprocal non-equilibrium counterparts - the inverse orbital Edelstein and inverse orbital Hall effects, as well as OAM conservation. We discuss the most salient achievements and the most pressing challenges in this rapidly evolving field, and in closing we highlight the future prospects of orbitronics.
Periodicity of Superatomic Hybrid Orbitals in Substituted Superatoms and Superatomic-like X@Ga12 (X = Li~Kr) Clusters
A superatom is a cluster composed of a specific number of atoms. We recently found that the superatom-like X@Ga12 (X = Li~Kr) clusters has the periodic energy levels of the specific orbitals 2S and 2P by means of the DV-Xα molecular orbital calculation method. This periodicity in energy levels has not been seen in 1D or 1F orbitals. We supposed that the periodicity of the energy levels of the 2S and 2P superatomic-like orbitals come from the same symmetry between atomic orbitals as the central atom X and the surrounding specific orbitals, according to the Jellium model. Both the s and p atomic orbitals of the central atom X in the superatom-like X@Ga12 have a large shielding effect, suggesting that the s and p atomic orbitals interact strongly with both 2S and 2P superatomic-like orbitals. The energy level periodicity has the potential to periodically change the number of electrons located in the 1D and 1F orbitals, which is related to magnetic properties and is expected to be useful for novel magnetic devices by periodically controlling the magnetism of superatoms.
Interdisciplinary care in orbital complications of acute rhinosinusitis in children
Purpose: Orbital cellulitis is a serious condition with potentially severe complications. Treatment requires interdisciplinary care and early introduction of antimicrobial therapy. In our tertiary center, a team of pediatricians, pediatric ophthalmologists, and otorhinolaryngologists successfully participated in the management of pediatric periorbital/orbital cellulitis. This study aimed to demonstrate our interdisciplinary approach and to investigate clinical profile and management of pediatric periorbital/orbital cellulitis. Methods: A retrospective chart review was performed of all pediatric patients hospitalized for periorbital and orbital cellulitis in a tertiary hospital center from September 15, 2016, to March 15, 2020. Results: A total of 26 children-median age 2.7 years (range 0.5-12)-were treated during the study period. Disease presentation was unilateral, mainly during winter (n = 12) and autumn (n = 12), without ophthalmoplegia/proptosis. Seven patients had orbital cellulitis (Chandler classification of ≥III) and were older (6.5 years, P = 0.011) with sinusitis (P < 0.001), required surgery (P = 0.004), underwent longer antimicrobial treatment (13 days, P < 0.001), and had a longer length of hospital stay (13.43 days, P = 0.001). Orbital cellulitis occurred in a median of three days (range 1-12) of acute rhinosinusitis. Radiological survey was performed in 11 patients, whereas six patients were treated surgically. All intraoperatively collected cultures (sinus swabs) were positive, whereas Streptococcus pyogenes and Peptostreptococcus were isolated in five cases. All patients fully recovered. No recurrence was documented. Conclusion: Sinusitis is associated with severe orbital cellulitis and surgical management. Orbital cellulitis occurred early in the course of acute rhinosinusitis, as a distinctive presentation of rhinosinusitis. Interdisciplinary care and early management are crucial in treatment of pediatric periorbital/orbital cellulitis.
Orbital Shadowing for C1-Generic Volume-Preserving Diffeomorphisms
We show that C1-generically, if a volume-preserving diffeomorphism has the orbital shadowing property, then the diffeomorphism is Anosov.
Epidemiological Overview and Traits into Disorders of the Orbital Walls in North-Eastern Romania
Background and Objectives: This study aimed to assess the frequency and distribution of facial bone injuries in terms of age, sex, residence, location, and etiology in the north-eastern region of Romania. Materials and Methods: This retrospective study was conducted within the Oral and Maxillofacial Clinics of “Sf. Spiridon” Hospital, Iași. The study group included 701 subjects (mean age 41.02 ± 18.45; sex: 603 males and 98 females) who were diagnosed with an orbital wall disorder. The epidemiological data on orbital wall fractures—including sociodemographic features, etiology, and location—were statistically analyzed. Results: The prevalence of orbital pathology was 1.47% congenital cases, 1.75% tumors, and 96.7% orbital fractures. The distribution of sex, age group, residence, and orbital localization varied significantly among the three diagnostic categories: tumors, congenital conditions, and fractures. Regarding sex, fractures were significantly more frequent in males (87.0%) compared to congenital cases (70.0%) and tumors (41.7%), while tumors showed a female predominance (58.3%) (p < 0.001). Congenital conditions predominantly affected patients under 20 years old (90.0%), whereas fractures were more evenly distributed across age groups, with higher frequencies between 31 and 50 years. In contrast, tumors involving the orbital walls were more frequent in older patients, with 33.3% in the 61–70 age group and 25.0% over 70 years. Regarding orbital localization, fractures were more likely to be bilateral (37.3%) or on the right side (44.3%), whereas congenital orbital defects and orbital tumors were predominantly unilateral and left-sided (70.0% and 66.7%, respectively). Bilateral involvement was rare in congenital cases (10.0%) and absent in tumors. Conclusions: The data support the finding that men are significantly more prone to trauma and orbital fractures, especially as a result of interpersonal violence and accidents, highlighting the need for preventive measures tailored to sex and socio-professional context.
Congenital orbital teratoma: a rare case with intracranial extension
Introduction Teratoma is the most common congenital tumor, but the orbital location is rare. It is composed of tissues from ectoderm, mesoderm, and endoderm. Clinical presentation Congenital orbital teratoma commonly presents as unilateral proptosis, with rapid growth, leading to exposure keratopathy. Diagnosis Prenatal ultrasound may detect the orbital mass, computed tomography (CT) scans, and magnetic resonance (MR) imaging are better in demonstrating multilocular cystic and solid mass, without bone erosion. Laboratory tests should include alfa-fetoprotein (AFP) and B-human chorionic gonadotropin (B-HCG), and histopathologically, it contains all three germ cell layers components. The management is surgical removal of the lesion, the mature teratoma has a benign behavior, and the immature has a poor prognostic. We describe a rare case of congenital orbital teratoma with intracranial extension of the lesion, in which was treated with orbital exenteration. After surgery, AFP levels decreased, the middle face displacement has improved and development milestones were appropriate.
Predicting the long-term stability of compact multiplanet systems
We combine analytical understanding of resonant dynamics in two-planet systems with machine-learning techniques to train a model capable of robustly classifying stability in compact multiplanet systems over long timescales of 10⁹ orbits. Our Stability of Planetary Orbital Configurations Klassifier (SPOCK) predicts stability using physically motivated summary statistics measured in integrations of the first 10⁴ orbits, thus achieving speed-ups of up to 10⁵ over full simulations. This computationally opens up the stability-constrained characterization of multiplanet systems. Our model, trained on ~100,000 three-planet systems sampled at discrete resonances, generalizes both to a sample spanning a continuous period-ratio range, as well as to a large five-planet sample with qualitatively different configurations to our training dataset. Our approach significantly outperforms previous methods based on systems’ angular momentum deficit, chaos indicators, and parametrized fits to numerical integrations. We use SPOCK to constrain the free eccentricities between the inner and outer pairs of planets in the Kepler-431 system of three approximately Earth-sized planets to both be below 0.05. Our stability analysis provides significantly stronger eccentricity constraints than currently achievable through either radial velocity or transit-duration measurements for small planets and within a factor of a few of systems that exhibit transit-timing variations (TTVs). Given that current exoplanet-detection strategies now rarely allow for strong TTV constraints [S. Hadden, T. Barclay, M. J. Payne, M. J. Holman, Astrophys. J. 158, 146 (2019)], SPOCK enables a powerful complementary method for precisely characterizing compact multiplanet systems. We publicly release SPOCK for community use.