Orbital States Research Articles

Spin‐Regulated Fenton‐Like Catalysis for Nonradical Oxidation over Metal Oxide@Carbon Composites

AbstractThe spin state of the transition metal species (TMs) has been recognized as a critical descriptor in Fenton‐like catalysis. The raised spin state of dispersed TMs in carbon will enhance the redox processes with adsorbed peroxides and improve the oxidation performance. Nevertheless, establishing the spin‐activity correlations for the encapsulated TM nanoparticles remains challenging because of the difficulties in fine‐tuning the spin state of TM species and the insufficient understanding of orbital hybridization states upon interaction with peroxides. Here, the advantage of the fast‐temperature heating/quenching of microwave thermal shock is taken to engineer the structure and spin state of encapsulated TMs within the N‐doped graphitic carbons. The reduced TMs particle size and enhanced TMs‐carbon coupling increase surface entropy and regulate eg electron filling of the high‐spin TM‐N coordination, endowing electrons with high mobility and facilitating peroxymonosulfate (PMS) adsorption. The strong interactions further uplift the PMS O 2p band position toward the Fermi level and thus elevate the oxidation potential of surface‐activated PMS (PMS*) as the dominant nonradical species for pollutant degradation. The deciphered orbital hybridizations of engineered high‐spin TM and PMS enlighten the smart design of spin‐regulated nanocomposites for advanced water purification.

Optical control of 4f orbital state in rare-earth metals.

A change of orbital state alters the coupling between ions and their surroundings drastically. Orbital excitations are hence key to understand and control interaction of ions. Rare-earth elements with strong magneto-crystalline anisotropy (MCA) are important ingredients for magnetic devices. Thus, control of their localized 4f magnetic moments and anisotropy is one major challenge in ultrafast spin physics. With time-resolved x-ray absorption and resonant inelastic scattering experiments, we show for Tb metal that 4f-electronic excitations out of the ground-state multiplet occur after optical pumping. These excitations are driven by inelastic 5d-4f-electron scattering, altering the 4f-orbital state and consequently the MCA with important implications for magnetization dynamics in 4f-metals and more general for the excitation of localized electronic states in correlated materials.

VOx-doped CoP catalysts with synergistic dual-active configuration for boosting hydrogen evolution kinetics

Hydrogen evolution reaction (HER), is of great significance to harvest H2 via energy-saving alkaline water electrolysis yet still challenging. Integrating heterogeneous materials is effective in designing favorable electrocatalysts for water dissociation (WD) and H-immediate involved adsorption/desorption behavior and triggering positive interactions to break the kinetics limitation. Herein, a promising configuration of a vanadium-oxide species integrated with cobalt-phosphide plane that grown on the nickel foam (labeled as VOx-CoP/NF), is demonstrated to boost the alkaline HER kinetics comprehensively. The doped vanadium-oxide species preferentially perform the WD process to generate H-intermediates. Meanwhile, interaction between VOx and CoP induce the electronic redistribution that optimizes 3d-2p orbital hybridization state, which balances the adsorption strength of H* to facilitate the hydrogen transfer and enrichment. Eventually, VOx-CoP/NF exhibits supereminent alkaline HER performance with an overpotential of only 65/245 mV at 10/400 mA cm−2, superior to individual CoP and most representative cobalt-phosphide candidates. A flowing anion exchange membrane (AEM) urea-assisted water electrolyzer with VOx-CoP/NF as a bifunctional catalyst, is assembled and achieves a satisfactory performance, verifying its practical feasibility for efficient H2 production. The concept exemplified in this work is that synchronous optimization of elementary reaction step kinetics of HER through reasonable constructing well-defined configuration is instructive for the design of HER electrocatalysts.

Influence of caffeine on the crystallinity and thermal stability of MAPbI3: Experiment and density-functional theory calculations

In this work, the effect of caffeine concentration (2 %, 4 %, 6 % and 8 %) on crystallinity and thermal stability of MAPbI3 was successfully studied. MAPbI3 showed stability at lower temperatures ranges between 0 and 90 °C, however, after adding caffeine the thermal stability showed an improvement towards higher temperatures [196–242 °C]. All the samples exhibited intense diffraction peaks at ∼2θ = 19.66° and 39.81°, respectively assigned to the (112) and (141) planes of tetragonal perovskite structure which indicates that the desired perovskite film was formed. MAPbI3@Caffeine (8 %) and MAPbI3@Caffeine (6 %) exhibited high PL intensity quenching which indicates their high charge carrier extraction efficacy which can be attributed to the higher crystallinity and fewer defect states of the film compared to MAPbI3@Caffeine (2 %) and MAPbI3@Caffeine (4 %) samples. MAPbI3@Caffeine (8 %) absorption spectra had the shifts to low wavelength in the range 491–532 nm which indicated that caffeine may allow sufficient photon into MAPbI3 due to the estimated bandgap. The density functional theory calculations suggest increased interactions at high caffeine concentration with corresponding switch from metallic to semiconducting properties. The stability of MAPbI3 can be attributed to increased cationic interaction between I 5p orbital states and C 2p, N 2p orbital states as indicated in the PDOS and electron density difference analysis.

Rapid Prediction of Energy Level Alignment and Conductance of Single‐Molecule Junctions Through Intramolecular Dipole Moment

AbstractHow substituents affect the conductance of single‐molecule junctions has been a subject of ongoing debate. Here, a comparative study on the transport properties across a broader range of experimentally proposed and representative π‐conjugated molecular systems, each characterized by prototypical backbone motifs with distinct terminal groups and featuring a range of substituents is conducted. Employing the non‐equilibrium Green's function method within density functional theory, this investigation reveals a significant impact on junction conductance due to asymmetric characteristics arising from both electronic and spatial effects induced by the di‐substituents of phenanthrene analogs with C═C or B─N motifs. Remarkably, a linear correlation is uncovered, either negative or positive, between the dipole moment of the molecules and the junction conductance, contingent upon whether the transport is governed by the highest occupied molecular orbital (HOMO) or lowest unoccupied molecular orbital (LUMO) states. Furthermore, the validity of this proposed dipole moment descriptor is substantiated across various substituted series, including 2,7‐dipyridylfluorene, oligo(phenylene ethynylene), and 1,4‐diaminobenzene. These findings underscore the pivotal role of individual molecular dipole moment, easily determinable, in offering precise predictive insight into the conductance of intricate molecular junctions.

Primary isolated extranodal NK/T-cell lymphoma of the orbit: A case report and diagnostic dilemma

Natural killer T-cell lymphoma (NKTL) is associated with Epstein-Barr virus, a highly malignant tumor that typically arises in the nose and/or paranasal sinuses isolated orbital involvement by NKTL is extremely rare. Herein, we report a case of primary orbital NKTL in a young female patient. A 32-year-old female presented with gradually increasing painful swelling of the right eye. On examination, abaxial proptosis, inferolateral displacement of the eyeball, restricted extraocular muscle movement, and solid mass in the subconjunctival fornix and superior quadrant. The rest of the ocular and systemic examination was unremarkable. Magnetic resonance imaging with contrast of the orbit shows a lobulated mass lesion 35×30×18 mm involving the medial aspect of the right orbit extraconal and superior intraconal space extending up to the preseptal region. Informed consent and biopsy were done and sent for histopathology examination. Histopathological examination shows the spectrum of atypical lymphoid cells, indented or cleaved nuclei and pale to clear cytoplasm, few histiocytes, giant cells, and apoptotic body. To rule out lymphoma, immunohistochemistry (IHC) was advised. On IHC, tumor cells were positive for CD3, D56, CD4 focally, CD7, Ki-67–90% and negative for CD20, CD2, Tdt, PAX5, CD34, CD5, Cd8 leading to a diagnosis of extranodal NKTL of the orbit. To the best of our knowledge, around 20 cases of isolated orbital extranodal NKTL were reported in the literature review. Polymorphic lymphoid cell in a young patient often mimics the inflammatory conditions of orbit. The rarity of this tumor and inflammatory signs make it challenging to identify these tumors early.

Visualization of orbital twig edge states in phononic graphene lattices

Visualization of orbital twig edge states in phononic graphene lattices

Likely Common Coronal Source of Solar Wind and 3He-enriched Energetic Particles: Uncoupled Transport from the Low Corona to 0.2 au

Parker Solar Probe (PSP) observations of a small dispersive event on 2022 February 27 and 28 indicate scatter-free propagation as the dominant transport mechanism between the low corona and greater than 35 solar radii. The event occurred during unique orbital conditions that prevailed along specific flux tubes that PSP encountered repeatedly between 25 and 35 Rs during outbound orbit 11. This segment of the PSP orbit exhibits almost stationary angular motion relative to the rotating solar surface, such that in the rotating frame, PSP’s motion is essentially radial. The time dispersion often observed in impulsive solar energetic particle (SEP) events continues in this case down to velocities including the core solar-wind ion velocities. Especially at the onset of this event, the 3He content is much larger than the usual SEP abundances seen in the energy range from ∼100 keV to several MeV for helium. Later in the event, iron is enhanced. The compositional signatures suggest this to be an example of an acceleration mechanism for generating the seed energetic particles required by shock (or compression) acceleration models in SEP events to account for the enrichment of various species above solar abundances in such events. A preliminary search of similar orbital conditions over the PSP mission has not revealed additional such events, although favorable conditions (isolated impulsive acceleration and well-ordered magnetic field connection with minimal magnetic field fluctuation) that would be required are infrequently realized, given the small fraction of the PSP trajectory that meets these observation conditions.

Ultrasound-Based Predictive Model to Assess the Risk of Orbital Malignancies

Ultrasound (US) is widely used for evaluating various orbital conditions. However, accurately diagnosing malignant orbital masses using US remains challenging. We aimed to develop an ultrasonic feature-based model to predict the presence of malignant tumors in the orbit. A total of 510 patients with orbital masses were enrolled between January 2017 and April 2023. They were divided into a development cohort and a validation cohort. In the development cohort (n = 408), the ultrasonic and clinical features with differential values were identified. Based on these features, a predictive model and nomogram were constructed. The diagnostic performance of the model was compared with that of MRI or observers, and further validated in the validation cohort (n = 102). The involvement of more than two quadrants, irregular shape, extremely low echo of the solid part, presence of echogenic foci, cast-like appearance, and two demographic characteristics (age and sex) were identified as independent features related to malignant tumors of the orbit. The predictive model constructed based on these features exhibited better performance in identifying malignant tumors compared to MRI (AUC = 0.78 [95% CI: 0.73, 0.82] vs. 0.69 [95% CI: 0.64, 0.74], p = 0.03) and observers (AUC = 0.93 [95% CI: 0.90, 0.95] vs. Observer 1, AUC = 0.80 [95% CI: 0.76, 0.84], p < 0.01; vs. Observer 2, AUC = 0.71 [95% CI: 0.66, 0.76], p < 0.01). In the validation cohort, the predictive model achieved an AUC of 0.88 (95% CI: 0.81, 0.94). The ultrasonic-clinical feature-based predictive model can accurately identify malignant orbital tumors, offering a convenient approach in clinical practice.

Cis-lunar and surface missions: Health risks and potential surgical conditions

The next goal of human space exploration is to return to the Moon to stay, and to establish a new, more advanced space station in lunar orbit: the ‘Lunar Gateway’. The authors aim to contribute to this goal through undertaking an ongoing comprehensive survey of relevant published scientific literature to seek information regarding the risk of medical conditions that might require operative or non-operative surgical solutions during long-duration spaceflight. The intended outcome is to create a roadmap for future mission planning. To date, we have identified more than 50 such potential surgical conditions. Based on disease severity and mission duration, these can be classified into: (Category 1) Time-critical conditions requiring immediate surgery; (Category 2) Urgent surgical conditions requiring minor temporising surgical intervention or conservative care (these patients can return to Earth for definitive treatment); or (Category 3) Non-urgent, as these conditions do not require immediate surgical intervention, and definitive treatment can be delayed. The proposed Lunar Gateway will be an international collaboration. Reaching Gateway is anticipated to take around three days. Gateway will operate in microgravity conditions, and include a communications lab (ground support from Earth is still available with minimal signal delay), a scientific lab, and a habitat for astronauts. Transfers to and from the lunar surface will allow astronauts to undertake extra-vehicular activities (EVA). Habitation on Gateway will present similar physiological and psychological challenges as experienced on the International Space Station (ISS), with the addition of a slightly increased communications lag. The Moon is only within Earth's magnetosphere for approximately 25 % of the time, which will increase space radiation exposure compared to the ISS. Gravitational conditions will range from microgravity on Gateway to ⅙ of the Earth's gravity on the lunar surface. Considering the duration and distance necessary in order to undertake a lunar mission, time-critical surgical interventions (Category 1) will likely be necessary, such as treating a bowel perforation, or fixation for musculoskeletal trauma. For urgent conditions (Category 2), antibiotic treatment of responsive appendicitis, drainage of uncomplicated cholecystitis, or other conservative measures might be acceptable as a temporising measure. If a return to Earth is possible within three days, delayed surgery can be undertaken if the conservative measures are unsuccessful, or the condition recurs. In the case of non-urgent procedures that can be delayed (Category 3), planned evacuation to Earth is expected to be available, for example, if a malignancy develops or is detected. Anticipating the medical and surgical challenges a lunar mission presents, and subsequent adequate planning and preparation for possible surgical emergencies, will help ensure mission success. Creating a system for triaging of surgical cases will be paramount in order to guide appropriate management.

Black hole solutions with constant Ricci scalar in a model of Finsler gravity

Ricci scalar being zero is equivalent to the vacuum field equation in Finsler space-time. The Schwarzschild metric can be concluded from the field equation's solution if the space-time conserves spherical symmetry. This research aims to investigate Finslerian Schwarzschild-de Sitter space-time. Recent studies based on Finslerian space-time geometric models are becoming more prevalent because the local anisotropic structure of space-time influences the gravitational field and gives rise to modified cosmological relations. We suggest a gravitational field equation with a non-zero cosmological constant in Finslerian geometry and apprehend that the presented Finslerian gravitational field equation corresponds to the non-zero Ricci scalar. In Finsler geometry, the peer of spherical symmetry is the Finslerian sphere. Assuming space-time to conserve the “Finslerian sphere” symmetry, the counterpart of the Riemannian sphere (Finslerian sphere) must have a constant flag curvature (λ). It is demonstrated that the Finslerian covariant derivative of the geometric part of the gravitational field equation is preserved under a condition using the Chern connection. According to the string theory, string clouds can be defined as a pool of strings made due to symmetry breaking in the universe's early stages. We find that for λ ≠ 1, this solution resembles a black hole surrounded by a cloud of strings. Furthermore, we investigate null and time-like geodesics for λ = 1. In this regard, the photon geodesics are obtained that are the closest paths to the photon sphere of the first photons visible at the black hole shadow limit. Also, circular orbit conditions are obtained for the effective potential.

Research on the Development Evaluation Method of TOD Development of Metro Station Domain

The public transport-oriented TOD model is a sustainable planning concept currently being implemented. It's in the TOD area. Most destinations can be reached directly by public transport. This emphasizes the attractiveness of public transport for residents to travel and reduces people's over-reliance on private cars, thereby improving urban problems such as diseases and traffic congestion in big cities. However, at present, the evaluation methods of TOD development effectiveness at home and abroad are insufficient in pertinence and timeliness, and can not fully evaluate the development effectiveness of TOD in orbital station area. This article takes the Beijing Metro Railway Station as an example to carry out the effective evaluation method of TOD development in the rail station domain. This paper tries to put forward a set of practical and effective evaluation methods for the development of orbital station TOD in Beijing. Therefore, it provides technical support for the further promotion of TOD development mode in the process of new city planning and old city renewal in Beijing.

Orbital dynamics of smart dust with Poynting–Robertson and solar wind drag

Smart dust devices are tiny systems-on-a-chip platforms capable of sensing, storing and transmitting data wirelessly as part of a large network with distributed capabilities. Previous works investigated the long-term orbital evolution of smart dust in space by studying the combined effect of gravitational perturbations, solar radiation pressure (SRP) and atmospheric drag. In the current work, the problem of finding long-term orbital equilibria conditions for smart dust is recast and extended to include Poynting–Robertson and Solar Wind (PRSW) drag. By including the PRSW effects and defining new equilibrium conditions on the orbital orientation, some additional partial equilibrium solutions are found. Moreover, it is shown that even though PRSW is not dominant compared to SRP or J2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$J_2$$\\end{document}, it still influences the evolution of the relative Sun-orbit orientation. For orbits with higher initial perigee altitudes, where drag and J2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$J_2$$\\end{document} effects subside, it is shown that PRSW influences long-term orbital behavior, and should be considered in the orbit design scheme of smart dust devices.

Chirality-selective topological magnon phase transition induced by interplay of anisotropic exchange interactions in honeycomb ferromagnet

A variety of distinct anisotropic exchange interactions commonly exist in one magnetic material due to complex crystal, magnetic and orbital symmetries. Here we investigate the effects of multiple anisotropic exchange interactions on topological magnon in a honeycomb ferromagnet, and find a chirality-selective topological magnon phase transition induced by a complicated interplay of Dzyaloshinsky–Moriya interaction and pseudo-dipolar interaction, accompanied by the bulk gap close and reopen with chiral inversion. Moreover, this novel topological phase transition involves band inversion at high symmetry points K and K′, which can be regarded as a pseudo-orbital reversal, i.e. magnon valley degree of freedom, implying a new manipulation corresponding to a sign change of the magnon thermal Hall conductivity. Indeed, it can be realized in 4d or 5d correlated materials with both spin–orbit coupling and orbital localized states, such as iridates and ruthenates, etc. This novel regulation may have potential applications on magnon devices and topological magnonics.

A Narrative Review on Neuro-Ophthalmological Manifestations That May Occur during Pregnancy.

As a medical condition, pregnancy mandates the simultaneous treatment of both the mother and the fetus, making it a distinctive aspect of clinical medicine. We analyze the physiological changes occurring in the eyes and brain during pregnancy, as well as the neuro-ophthalmological manifestations that can occur during pregnancy. Studies published in both English and other languages, case reports, and reviews from 2011 to 2023 onwards were included. All surveys were acquired by exploring the databases. We found a total of 2135 articles that showcase neuro-ophthalmic changes related to pregnancy: review and research articles (Science Direct 804, Web of Science 923, Scopus 345, and 63 Pub Med). In total, 86 studies were examined after applying the inclusion and exclusion criteria. Bilateral papilledema can be a warning sign for intracranial hypertension or cerebral venous sinus thrombosis. Additionally, when unilateral, it is important to differentially diagnose anterior ischemic optic neuropathy secondary to a hypercoagulant, compressive or inflammatory optic neuropathy, optic neuritis, or even orbital pseudotumor state. Severe eclampsia and preeclampsia can manifest as choroidal infarction, serous retinal detachment, and even cortical blindness. There can also be implications at the level of cranial nerves or transient Horner syndrome. Evaluating and treating a pregnant woman with neuro-ophthalmological manifestations is challenging. The obstetrician closely follows and has a medical relationship with the pregnant woman; hence he/she might be the first to be informed about the general condition of the pregnant woman or might request an ophthalmologic examination tailored to each specific case.

Neural Network-Based Formation Flying Using Aerodynamic Forces via Variable Shape Function

Conventional formation flying Earth-orbiting satellites control their orbits to perform their missions using thrusters, but the amount of propellant loaded into a satellite is limited. Therefore, the use of aerodynamic forces for orbit control has been attracting attention, particularly in low Earth orbit. The orbit control can be achieved by appropriately changing the state of satellite, such as attitude and shape, to meet the aerodynamic requirements. In modeling the relationship between satellite state and aerodynamic forces, conventional methods ignore the shielding caused by the nonconvexity of the satellite’s appearance. Ignoring the shielding creates a gap between the modeled and the real aerodynamic forces, resulting in poor control performance. To solve this problem, we propose an aerodynamic force modeling method that incorporates a neural network to estimate the shielding. We train the neural network using data from an aerodynamics simulator. The optimal state that not only generates the required aerodynamic forces but also improves controllability under various mechanical constraints is obtained by solving an optimization problem that incorporates the proposed aerodynamic model. We conduct numerical simulations for establishing and maintaining general circular orbit formations. The results show convergence and continuous stable control of the deputy satellite to the ideal orbit.

The quantum states for Hydrogen atom: spherical harmonics and the orbitals geometrical representation

Our work utilizes the quantum model of the hydrogen atom which is based on the Schrödinger equation with Coulomb potential. Specifically, we concentrate on the angular components of the wave eigenfunctions derived from this model. We consider the quantum states with n ≤ 4. In order to visualize the orbital shapes of these states, we built in the spherical coordinates system their 3D geometric representations. Furthermore, we use the corresponding spherical harmonics, to calculate the θ nodal values that describe the configurations of these orbital states.

An orbit determination software suite for Space Surveillance and Tracking applications

The growth of both operational satellites and orbital debris is creating the requirement for more robust Space Surveillance and Tracking (SST)-related applications. These systems necessarily must leverage ground-based sensors (optical and radar) to realise higher performance solutions. In this context, the European Union Space Surveillance and Tracking (EUSST) consortium groups European national agencies and institutions, and is in charge of carrying out the following services: conjunction analysis, fragmentation analysis and re-entry prediction, and the Italian Air Force is in charge of the latter two. In this framework, the Italian SST Operational Centre (ISOC) has recently upgraded its system to the ISOC Suite, an integrated platform providing multiple functions and services in the SST domain. This paper presents the orbit determination functions provided by the novel ISOC Suite. First, a statistical index is computed to assess the measurements correlation to a catalogued object. If it is successful, the object predicted orbit is refined through measurements according either to batch or sequential filters; otherwise these are used to refine a first estimate of the target orbital state computed according to dedicated methodologies. After the presentation of the prototypal software architecture, the ISOC Suite performance are assessed and discussed both in terms of synthetic and real data.

Variation of magnetic properties with current in ferrimagnetic semiconductor Mn3Si2Te6

Orbital currents play a fundamental role in a wide range of transport phenomena. Recently, the discovery of a novel chiral orbital current state in the ferrimagnetic nodal-line semiconductor Mn3Si2Te6 has attracted significant interest, supported by anomalous I–V characteristics and time-dependent bistable switching. However, the direct experimental verifications, combining electrical transport and magnetic measurement, that detect the variation of the magnetic properties vs the current are still rare. Here, we investigate the transport properties of Mn3Si2Te6 and track the current-induced dynamics of the magnetic moment. Reflective magnetic circular dichroism reveals that significant alterations in Mn3Si2Te6 magnetoresistance in response to an electric field are necessarily coupled with a magnetic phase transition, establishing a rare correlation. Our findings indicate the predominance of magnetic chiral orbital currents in the colossal angular magnetoresistance effect, offering a unique platform for advanced studies in orbital magnetism.

Clinician's approach for spectrum of orbital diseases: An overview.

To study the varied clinical presentation and outcome of management of orbital diseases and to ascertain the concordance of FNAC with histopathology. This is a prospective interventional study wherein each patient's clinical presentation was noted. Outcome of management was evaluated based on symptomatic relief, regression of signs, noting any intraoperative or postsurgical complication, recurrence, and cosmetic result in terms of surgical scar. Neoplasia was commonest 33/76; (43.42%), followed by infective and inflammatory conditions 21/76; (27.63% cases), thyroid-associated orbitopathy accounting for 12/76 cases (15.78%), whereas cystic lesions and vascular malformations were 4/76 (5.26%) each. Other disorders constituted a mere 2.65%. Proptosis was the commonest mode of presentation. It was seen in seventy out of seventy-six patients (92.1%). In 86.3% of the cases, there was successful surgical outcome. Of 22 surgically managed cases, recurrence was noted in three cases (13.6%). 90% concordance was seen with histopathology in cases where FNAC was done prior to surgery for diagnosing nature of disease. Majority of orbital and adnexal conditions can be provisionally diagnosed based on imaging; however, an adjunct invasive investigation such as FNAC or biopsy may be required. In the present study, in seven cases (9.2%) FNAC was needed, whereas in two cases (2.63%) biopsy was needed. A definitive diagnosis was confirmed by histopathology in 22 surgically managed cases and by excision biopsy in two. 22/76 (28.94%) of the cases needed surgical treatment, and other cases required conservative or palliative approach.