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Magneto-optical effects (MOE), interfacing the fundamental interplay between magnetism and light, have served as a powerful probe for magnetic order, band topology, and valley index. Here, based on multiferroic and topological bilayer antiferromagnets (AFMs), we propose a layer control of MOE (L-MOE), which is created and annihilated by layer-stacking or an electric field effect. The key character of L-MOE is the sign-reversible response controlled by ferroelectric polarization, the Néel vector, or the electric field direction. Moreover, the sign-reversible L-MOE can be quantized in topologically insulating AFMs. We reveal that the switchable L-MOE originates from the combined contributions of spin-conserving and spin-flip interband transitions in spin-valley splitting AFMs, a phenomenon not observed in conventional AFMs. Our findings bridge the ancient MOE to the emergent realms of layertronics, valleytronics, and multiferroics and may hold immense potential in these fields.
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BACKGROUND: Thyroid eye disease (TED) is highly correlated with dysregulated immunoendocrine status. The insular cortex was found to regulate peripheral inflammation and immunomodulation in mice. This study aimed to explore whether the insular cortex in patients with TED played a modulatory role including the aberrant brain functional alteration and its association with immunoendocrine status. METHODS: This study included 34 active patients (AP), 30 inactive patients (IP) with TED, and 45 healthy controls (HC) matched for age, sex, and educational level. Comprehensive clinical details (especially immunoendocrine markers) and resting-state functional magnetic resonance imaging data were collected from each participant. The amplitude of low-frequency fluctuation (ALFF) was used to probe the aberrant alterations of local neural activity. The seed-based functional connectivity (FC) analysis was used to explore the relationship between the insular cortex and each voxel throughout the whole brain. The correlation analysis was conducted to assess the association between insular neurobiomarkers and immunoendocrine parameters. RESULTS: When compared with the IP and HC groups, the AP group displayed significantly higher ALFF values in the right insular cortex (INS.R) and lower FC values between the INS.R and the bilateral cerebellum. None of the neurobiomarkers differed between the IP and HC groups. Besides, correlations between insular neurobiomarkers and immunoendocrine markers (free thyroxine, the proportion of T cells, and natural killer cells) were identified in both AP and IP groups. CONCLUSIONS: This study was novel in reporting that the dysregulation of the insular cortex activity in TED was associated with abnormal peripheral immunoendocrine status. The insular cortex might play a key role in central-peripheral system interaction in TED. Further research is crucial to enhance our understanding of the central-peripheral system interaction mechanisms involved in autoimmune diseases.
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Oftalmopatía de Graves , Corteza Insular , Humanos , Animales , Ratones , Imagen por Resonancia Magnética/métodos , Neuroimagen , Encéfalo , Mapeo Encefálico/métodosRESUMEN
Transition metal dichalcogenides (TMDs) exhibit excellent electronic and photoelectric properties under pressure, prompting researchers to investigate their structural phase transitions, electrical transport, and photoelectric response upon compression. Herein, the structural and photoelectric properties of layered ZrS2 under pressure using in situ high-pressure photocurrent, Raman scattering spectroscopy, alternating current impedance spectroscopy, absorption spectroscopy, and theoretical calculations are studied. The experimental results show that the photocurrent of ZrS2 continuously increases with increasing pressure. At 24.6 GPa, the photocurrent of high-pressure phase P21/m is three orders of magnitude greater than that of the initial phase P 3 ¯ m 1 $P\bar{3}m1$ at ambient pressure. The minimum synthesis pressure for pure high-pressure phase P21/m of ZrS2 is 18.8 GPa, which exhibits a photocurrent that is two orders of magnitude higher than that of the initial phase P 3 ¯ m 1 $P\bar{3}m1$ and displays excellent stability. Additionally, it is discovered that the crystal structure, electrical transport properties and bandgap of layered ZrS2 can also be regulated by pressure. This work offers researchers a new direction for synthesizing high-performance TMDs photoelectric materials using high pressure, which is crucial for enhancing the performance of photoelectric devices in the future.
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BACKGROUND: Radiomics analysis of orbital magnetic resonance imaging (MRI) shows preliminary potential for intravenous glucocorticoid (IVGC) response prediction of thyroid eye disease (TED). The current region of interest segmentation contains only a single organ as extraocular muscles (EOMs). It would be of great value to consider all orbital soft tissues and construct a better prediction model. METHODS: In this retrospective study, we enrolled 127 patients with TED that received 4·5 g IVGC therapy and had complete follow-up examinations. Pre-treatment orbital T2-weighted imaging (T2WI) was acquired for all subjects. Using multi-organ segmentation (MOS) strategy, we contoured the EOMs, lacrimal gland (LG), orbital fat (OF), and optic nerve (ON), respectively. By fused-organ segmentation (FOS), we contoured the aforementioned structures as a cohesive unit. Whole-orbit radiomics (WOR) models consisting of a multi-regional radiomics (MRR) model and a fused-regional radiomics (FRR) model were further constructed using six machine learning (ML) algorithms. RESULTS: The support vector machine (SVM) classifier had the best performance on the MRR model (AUC = 0·961). The MRR model outperformed the single-regional radiomics (SRR) models (highest AUC = 0·766, XGBoost on EOMs, or LR on OF) and conventional semiquantitative imaging model (highest AUC = 0·760, NaiveBayes). The application of different ML algorithms for the comparison between the MRR model and the FRR model (highest AUC = 0·916, LR) led to different conclusions. CONCLUSIONS: The WOR models achieved a satisfactory result in IVGC response prediction of TED. It would be beneficial to include more orbital structures and implement ML algorithms while constructing radiomics models. The selection of separate or overall segmentation of orbital soft tissues has not yet attained its final optimal result.
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Oftalmopatía de Graves , Humanos , Oftalmopatía de Graves/diagnóstico por imagen , Glucocorticoides/uso terapéutico , Estudios Retrospectivos , Órbita/diagnóstico por imagen , Radiómica , Imagen por Resonancia Magnética/métodos , Aprendizaje AutomáticoRESUMEN
BACKGROUND: Thyroid eye disease (TED), particularly its sight-threatening complication, dysthyroid optic neuropathy (DON), profoundly impacts patients' visual health. The pathological changes in the white matter (WM) fibers within the intracranial visual pathway in TED have been infrequently studied. Understanding these changes holds crucial importance for exploring the pathogenesis and prognosis of TED. PURPOSE: To utilize fixel-based analysis (FBA) to clarify the type of microstructural damage occurring in the visual pathway in TED. STUDY TYPE: Prospective. SUBJECTS: 28 TED with DON patients (11 males and 17 females), 28 TED without DON (non-DON) patients (12 males and 16 females), and 28 healthy controls (HCs) (12 males and 16 females). FIELD STRENGTH/SEQUENCE: 3 T; multishell diffusion MRI using echo planar imaging. ASSESSMENT: Fiber density (FD) and fiber-bundle cross-section (FC) were calculated to characterize WM microstructural alteration in TED visual pathway. The correlations between FBA metrics and visual field index and mean deviation were examined. STATISTICAL TESTS: One-way analysis of variance, Kruskal-Wallis, t-tests, Mann-Whitney U, Chi-square, and Pearson correlation, were conducted with false discovery rate and family wise error corrections. Significance was set at P < 0.05. RESULTS: Both DON and non-DON groups showed significant FD loss in the right optic tract compared with HCs, with DON patients experiencing more severe FD loss. Only DON patients had FD loss in the right optic radiation (OR) compared with the non-DON patients and HCs, with no FC difference across groups. FD in DON patients' ORs significantly correlated with visual field index (r = 0.857) and mean deviation (r = 0.751). DATA CONCLUSION: Both DON and non-DON affect the WM microstructure of the visual pathway to varying extents. Visual field metrics can reflect the severity of FD damage to the OR in the visual pathway of DON patients. EVIDENCE LEVEL: 2. TECHNICAL EFFICACY: Stage 3.
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OBJECTIVES: To investigate the pathological interplay between immunity and the visual processing system (VPS) in thyroid eye disease (TED). METHODS: A total of 24 active patients (AP), 26 inactive patients (IP) of TED, and 27 healthy controls (HCs) were enrolled. Orbital magnetic resonance imaging (MRI) and resting-state functional MRI (rs-fMRI) were conducted for each participant. Multiple MRI parameters of the intraorbital optic nerve (ON) were assessed. The amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo) were calculated. Correlation analyses were carried out on the above parameters and clinical characteristics. RESULTS: Visual functioning scores differentiated between the AP and IP groups. The ON subarachnoid space and ON sheath diameter were significantly higher in AP than in IP. Six vision-related brain regions were identified in TED patients compared with HCs, including right calcarine (CAL.R), right cuneus (CUN.R), left postcentral gyrus (PoCG.L), right middle temporal gyrus (MTG.R), left superior frontal gyrus (SFG.L), and left caudate (CAU.L). The brain activity of MTG.R, SFG.L, and CAU.L differentiated between the AP and IP groups. The correlation analysis revealed a close association among the vision-related brain regions, MRI parameters of ON, and clinical characteristics in AP and IP, respectively. CONCLUSIONS: Combined orbital and brain neuroimaging revealed abnormalities of the VPS in TED, which had a close correlation with immune statuses. Vision-related brain regions in TED might be possibly altered by peripheral immunity via a direct or indirect approach. CLINICAL RELEVANCE STATEMENT: The discovery of this study explained the disparity of visual dysfunction in TED patients with different immune statuses. With the uncovered neuroimaging markers, early detection and intervention of visual dysfunction could be achieved and potentially benefit TED patients. KEY POINTS: ⢠Patients with different immune statuses of thyroid eye disease varied in the presentation of visual dysfunction. ⢠The combined orbital and brain neuroimaging study identified six altered vision-related brain regions, which had a significant correlation with the MRI parameters of the intraorbital optic nerve and immunological characteristics. ⢠Peripheral immunity might possibly give rise to alterations in the central nervous system part of the visual processing system via a direct or indirect approach.
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Oftalmopatía de Graves , Imagen por Resonancia Magnética , Neuroimagen , Humanos , Masculino , Femenino , Imagen por Resonancia Magnética/métodos , Oftalmopatía de Graves/diagnóstico por imagen , Oftalmopatía de Graves/complicaciones , Oftalmopatía de Graves/inmunología , Persona de Mediana Edad , Adulto , Neuroimagen/métodos , Encéfalo/diagnóstico por imagen , Trastornos de la Visión/diagnóstico por imagen , Trastornos de la Visión/etiología , Trastornos de la Visión/fisiopatología , Estudios de Casos y Controles , Nervio Óptico/diagnóstico por imagen , Nervio Óptico/patología , Órbita/diagnóstico por imagenRESUMEN
High-pressure phase diagrams of the La-N binary system were systematically constructed using the CALYPSO method and first-principles calculations. In addition to the pressure-induced La-N compounds reported previously, we have uncovered a hitherto unknown LaN9 structure in Pm3Ì symmetry stabilized within a narrow pressure range of 20-24.5 GPa. Notably, LaN9 stands as the first thermodynamically stable metal nine-nitrogen compound, featuring centrosymmetric linear N3 anion units and an edge-sharing LaN12 icosahedron. Charge transfer between the La and N atoms plays a crucial role in facilitating structural stability. Furthermore, we identified a novel Cm phase for LaN8, which has a lower enthalpy compared to the previously reported phase. N atoms in Cm LaN8 are polymerized into infinite N∞ chains. Calculations demonstrate the potential recoverability of LaN9 and Cm LaN8 under atmospheric conditions while preserving their initial polynitrogen configuration. From the perspective of detonation pressure and detonation velocity, LaN9 and Cm LaN8 exhibit excellent explosive performance in comparison to TNT and HMX, with estimated energy densities of 0.9 and 1.54 kJ g-1, respectively, indicating their potential utility as high-energy-density materials.
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A material with the "hidden" negative linear compressibility (NLC) will expand along a specific crystal direction upon uniformly compression to a critical pressure; such materials are thought to be promising candidates for non-linear actuators, switches and sensors. Herein, we use density functional theory (DFT) calculations to uncover the hidden NLC in a V-shaped molecular crystal, bis(5-amino-1,2,4-triazol-3-yl)methane (BATZM). The calculations indicate that the crystal is normally compressed over the pressure range of 0-3 GPa while it expands along the b-axis when the external hydrostatic pressure exceeds 3 GPa. The compressive behavior of the BATZM crystal is modulated by inter-molecular hydrogen bonds, which act as highly compressible springs at low pressures but robust struts at high pressures. Hence, the crystal prefers to compress the hydrogen bonds coupled with PLC at first and flatten the molecules, coupled with later NLC to resist the increasing external pressure. The compressive behavior of BATZM provides a strategy to design more hidden NLC materials via the rational use of the hydrogen bonds.
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Inert gases (e.g., He and Xe) can exhibit chemical activity at high pressure, reacting with other substances to form compounds of unexpected chemical stoichiometry. This work combines first-principles calculations and crystal structure predictions to propose four unexpected stable compounds of CH4Xe3, (CH4)2Xe, (CH4)3Xe, and (CH4)3Xe2 at pressure ranges from 2 to 100 GPa. All structures are composed of isolated Xe atoms and CH4 molecules except for (CH4)3Xe2, which comprises a polymerization product, C3H8, and hydrogen molecules. Ab initio molecular dynamics simulations indicate that pressure plays a very important role in the different temperature driving state transitions of CH4-Xe compounds. At lower pressures, the compounds follow the state transition of solid-plastic-fluid phases with increasing temperature, while at higher pressures, the stronger Xe-C interaction induces the emergence of a superionic state for CH4Xe3 and (CH4)3Xe2 as temperature increases. These results not only expand the family of CH4-Xe compounds, they also contribute to models of the structures and evolution of planetary interiors.
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PURPOSE: To provide an in-depth analysis of the association of peripheral lymphocytes and the disease activity of thyroid eye disease (TED). METHODS: This retrospective study enrolled 65 active TED patients and 46 inactive TED patients. Comparative analyses of peripheral lymphocyte subsets were conducted between active and inactive patients. Subgroup analyses were performed based on sex, age, disease duration, and severity. Correlation analyses explored the associations between lymphocyte subsets and TED activity indicators. Prediction models for TED activity were established using objective indicators. RESULTS: Significantly elevated levels of CD3+CD4+ T cells were observed in active TED patients compared to inactive patients (P = 0.010). Subgroup analyses further revealed that this disparity was most prominent in females (P = 0.036), patients aged 50 years and younger (P = 0.003), those with long-term disease duration (P = 0.022), and individuals with moderate-to-severe disease (P = 0.021), with age exerting the most substantial impact. Subsequent correlation analysis confirmed the positive association between CD3+CD4+ T cells and the magnetic resonance imaging indicator of TED activity among patients aged 50 years and younger (P = 0.038). The combined prediction models for TED activity, established using objective indicators including CD3+CD4+ T cells, yielded areas under curve of 0.786 for all patients and 0.816 for patients aged 50 years and younger. CONCLUSIONS: Peripheral CD3+CD4+ T cells are associated with disease activity of TED, especially in patients aged 50 years and younger. Our study has deepened the understanding of the peripheral T cell profiles in TED patients.
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The quantum anomalous Hall effect (QAHE) is a highly researched topic in condensed matter physics due to its ability to enable dissipationless transport. Previous studies have mainly focused on the ferromagnetic QAHE, which arises from the combination of collinear ferromagnetism and two-dimensional (2D) Z2 topological insulator phases. In our study, we demonstrate the emergence of the spin-chirality-driven QAHE and the quantum topological Hall effect (QTHE) by sandwiching a 2D Z2 topological insulator between two chiral kagome antiferromagnetic single-layers synthesized experimentally. The QAHE is surprisingly realized with fully compensated noncollinear antiferromagnetism in contrast to conventional collinear ferromagnetism. The Chern number can be regulated periodically with the interplay between vector- and scalar-spin chiralities, and the QAHE emerges even without spin-orbit coupling, indicating the rare QTHE. Our findings open a new avenue for realizing antiferromagnetic quantum spintronics based on the unconventional mechanisms from chiral spin textures.
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PURPOSE: This study aimed to explore the diagnostic value of whole-orbit-based multiparametric assessment on Dixon MRI for the evaluation of the thyroid eye disease (TED) activity. METHODS: The retrospective study enrolled patients diagnosed as TED and obtained their axial and coronal Dixon MRI scans. Multiparameters were assessed, including water fraction (WF), fat fraction (FF) of extraocular muscles (EOMs), orbital fat (OF), and lacrimal gland (LG). The thickness of OF and herniation of LG were also measured. Univariable and multivariable logistic regression was applied to construct prediction models based on single or multiple structures. Receiver operating characteristic (ROC) curve analysis was also implemented. RESULTS: Univariable logistic analysis revealed significant differences in water fraction (WF) of the superior rectus (P = 0.018), fat fraction (FF) of the medial rectus (P = 0.029), WF of OF (P = 0.004), and herniation of LG (P = 0.012) between the active and inactive TED phases. Multivariable logistic analysis and corresponding receiver operating characteristic curve (ROC) analysis of each structure attained the area under the curve (AUC) values of 0.774, 0.771, and 0.729 for EOMs, OF, and LG, respectively, while the combination of the four imaging parameters generated a final AUC of 0.909. CONCLUSIONS: Dixon MRI may be used for fine multiparametric assessment of multiple orbital structures. The whole-orbit-based model improves the diagnostic performance of TED activity evaluation.
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Oftalmopatía de Graves , Músculos Oculomotores , Órbita , Curva ROC , Humanos , Masculino , Femenino , Oftalmopatía de Graves/diagnóstico , Oftalmopatía de Graves/diagnóstico por imagen , Estudios Retrospectivos , Persona de Mediana Edad , Órbita/diagnóstico por imagen , Órbita/patología , Músculos Oculomotores/diagnóstico por imagen , Músculos Oculomotores/patología , Adulto , Anciano , Imágenes de Resonancia Magnética Multiparamétrica/métodos , Imagen por Resonancia Magnética/métodos , Aparato Lagrimal/diagnóstico por imagen , Aparato Lagrimal/patologíaRESUMEN
Pressure-stabilized hydrides have potential as an outstanding reservoir for high-temperature (Tc) superconductors. We undertook a systematic study of crystal structures and superconducting properties of gallium hydrides using an advanced structure-search method together with first-principles calculations. We identified an unconventional stoichiometric GaH7 gallium hydride that is thermodynamically stable at pressures above 247 GPa. Interestingly, the H atoms are clustered to form a unique H7 chain intercalating the Ga framework. Further calculations show a high estimated Tc above 100 K at 200-300 GPa for GaH7, closely related to the strong coupling between electrons of Ga and H atoms, and phonon vibrations of H7 chains. Our work provides an example of exploration for diverse superconducting hydrogen motifs under high pressure, and may stimulate further experimental syntheses.
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Water and nitrogen are abundant in the Earth's interior and atmosphere, and their mixture under high pressure is a fundamental and valuable scientific issue for physics and chemical science. Based on structural prediction and first-principles simulations, we propose that the two nitrogen-rich stoichiometries, H2ON6 and H2ON10, become energetically stable above â¼70 GPa. Further ab initio molecular dynamics calculations indicate that H2ON6 and H2ON10 undergo phase transitions from solid to superionic and finally to fluid phase with increasing temperature. The superionic regions in their phase diagram correspond to the extreme conditions of Earth's mantle, implying that the Earth's interior might be a possible reservoir of the N-rich hydrates. In addition, H2ON6 remains dynamically stable under ambient conditions with an estimated energy density of 6.53 kJ g-1, indicating that it might be a high-energy density material. These results not only provide essential information for the understanding of the Earth's interior, but also provide guidance for the design of high-energy density materials.
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The magnetic properties and electrical transport behaviors of half-metallic ferromagnet chromium dioxide (CrO2) powders under high pressure have been investigated by in situ electrical resistivity, magneto-resistivity, and Hall-effect measurements. Our results reveal that the Hall coefficient, carrier concentration, and mobility all present discontinuous changes from 11.7 GPa to 14.9 GPa which can be attributed to the second-order structural transition from the rutile-type to CaCl2-type. However, the resistivity decreases monotonically from ambient pressure to 16.5 GPa. This is due to, first, the decreased carrier concentration and the increased carrier mobility canceling the effects of each other on the resistivity; second, according to the calculation results, the bandgap of CrO2 decreased gradually with the pressure, and the bandgaps of the rutile-type phase and the CaCl2-type phase are extremely similar. CrO2 exhibits a linear and negative magnetoresistance under the applied magnetic field (0â¼ ± 15 kOe). As the pressure increases, the magnetoresistance remains negative, but it becomes nonlinear and less symmetric, suggesting that pressure has an appreciable impact on the double-exchange mechanism leading to ferromagnetism in CrO2.
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BACKGROUND: Computed tomography (CT) can avoid interference factors and has been imported into some software to measure proptosis clinically as the golden standard. PURPOSE: To establish a new method for semi-automatically measuring the proptosis on CT and evaluate its accuracy and reproducibility. MATERIAL AND METHODS: A total of 50 orbital CT images were collected of healthy individuals, 25 patients with Graves ophthalmopathy (GO), and 25 patients with orbital fracture (OF). A new image processing software, MedrawHDC, was developed to semi-automatically measure the proptosis (MedrawHDC method). The classic radiological (CR) method (measuring proptosis with the software called Mimics) and MedrawHDC method were applied in all three groups (measured by observer S). Hertel's exophthalmometer (HE) method was also applied in the GO group. Moreover, two other observers were asked to measure the proptosis using MedrawHDC, to evaluate its reproducibility. RESULTS: The MedrawHDC method was highly consistent with the CR method in measuring proptosis (normal group: intraclass correlation coefficient [ICC] = 0.989; GO group: ICC = 0.979; OF group: ICC = 0.979). In the GO group, the value of proptosis measured by two radiological methods were consistent with that measured by the HE method (CR method: ICC = 0.703; MedrawHDC method: ICC = 0.697). Bland-Altman plots showed similar results. The measurements obtained by three observers were highly reproducible (ICC = 0.995). CONCLUSION: The newly established MedrawHDC method, with high accessibility, convenience, and repeatability, is reliable in assessing proptosis. It shows high potential for wide application, having clinical value for scientific evaluation of proptosis.
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Exoftalmia , Oftalmopatía de Graves , Fracturas Orbitales , Humanos , Reproducibilidad de los Resultados , Exoftalmia/diagnóstico por imagen , Oftalmopatía de Graves/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Variaciones Dependientes del ObservadorRESUMEN
PURPOSE: To analyze the displacement of orbital soft tissue after blow-out fracture (BOF) repair with poly (L-lactide-co-glycolide) plates. MATERIALS AND METHODS: In this retrospective study, all patients who had undergone repair operations for orbital BOF from 2017 to 2021 were evaluated. Poly (L-lactide-co-glycolide) plates were used as repair materials. Preoperative and postoperative computed tomography images were integrated into the same coordinate system applying image fusion technique and were compared to determine the maximum displacement of orbital tissue after surgical repair. RESULTS: A total of 15 patients were included. Five were male, and 10 were female. Mean age was 33±16 years. Median waiting period was 18 (12-23) days. Six cases were medial wall fractures, 5 were floor fractures, and 4 were combined fractures. Maxillo-ethmoidal strut was involved in 4. Mean defect area was 176.52±108.48 mm 2 . Median interval between postoperative imaging examinations was 292 (223-600) days. Mean orbital tissue displacement was 2.6±1.8 mm. Using simple and multivariable linear regression analysis, the fracture defect area ( P =0.001) and maxillo-ethmoidal strut involvement ( P =0.013) were found to be significantly associated with orbital tissue displacement. Median orbital volume change was 0.804 (0.647-1.010) cm 3 . Average proptosis variation was 1.2±0.8 mm. CONCLUSIONS: Poly (L-lactide-co-glycolide) plates were more suitable for orbital BOF with small defect size. Those with large defect or maxillo-ethmoidal strut involved might have greater tissue displacements due to decline of supporting strength of poly (L-lactide-co-glycolide) plates.
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Fracturas Orbitales , Humanos , Masculino , Femenino , Adolescente , Adulto Joven , Adulto , Persona de Mediana Edad , Fracturas Orbitales/cirugía , Polímeros , Estudios Retrospectivos , DioxanosRESUMEN
Crystal structure predictions and first-principles calculations were used to predict three polynitrogen solids (aP8-N, aP12-N, and oP24-N) that possess competitive enthalpies as compared to the synthesized open-chain N8 phase at pressures in the range of 0-60 GPa. aP8-N, aP12-N, and oP24-N contain edge-shared, N2-linked, and N-bridged pentazolate rings and form molecular N8, molecular N12, and quasi-one-dimensional N∞ ribbons, respectively. The calculations of formation enthalpies show that the three polynitrogen solids can be synthesized by compressing cyclo-N5 salts in hydrogen-saturated environments. Molecular simulations suggest that the three polynitrogen solids have the ability of quench recoverability under ambient conditions once being synthesized at high pressure. With estimated energy densities in the range of 5.6-6.5 kJ/g, these three polynitrogen phases show notable promise for applications as high-energy-density materials.
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The quantum nature of the proton can crucially affect the structural and physical properties of hydrogen compounds. For example, in the high-pressure phases of H2O, quantum proton fluctuations lead to symmetrization of the hydrogen bond and reduce the boundary between asymmetric and symmetric structures in the phase diagram by 30 gigapascals (ref. 3). Here we show that an analogous quantum symmetrization occurs in the recently discovered sulfur hydride superconductor with a superconducting transition temperature Tc of 203 kelvin at 155 gigapascals--the highest Tc reported for any superconductor so far. Superconductivity occurs via the formation of a compound with chemical formula H3S (sulfur trihydride) with sulfur atoms arranged on a body-centred cubic lattice. If the hydrogen atoms are treated as classical particles, then for pressures greater than about 175 gigapascals they are predicted to sit exactly halfway between two sulfur atoms in a structure with Im3m symmetry. At lower pressures, the hydrogen atoms move to an off-centre position, forming a short H-S covalent bond and a longer H···S hydrogen bond in a structure with R3m symmetry. X-ray diffraction experiments confirm the H3S stoichiometry and the sulfur lattice sites, but were unable to discriminate between the two phases. Ab initio density-functional-theory calculations show that quantum nuclear motion lowers the symmetrization pressure by 72 gigapascals for H3S and by 60 gigapascals for D3S. Consequently, we predict that the Im3m phase dominates the pressure range within which the high Tc was measured. The observed pressure dependence of Tc is accurately reproduced in our calculations for the phase, but not for the R3m phase. Therefore, the quantum nature of the proton fundamentally changes the superconducting phase diagram of H3S.
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PURPOSE: This study aims to evaluate the efficacy and safety of intralesional diode laser pretreatment for facilitating surgery for orbital venous malformations (OVMs). METHODS: This is a retrospective, non-comparative, interventional cohort involving 23 consecutive OVM patients undergoing intralesional laser pretreatment followed by surgical excision. The main outcome measures included volumetric changes, exophthalmometry, cosmesis, and symptom scores as well as treatment-related adverse events. RESULTS: Following intralesional diode laser, the mean volume dropped significantly from 2366 ± 1887 to 129 ± 119 mm3 (t = 5.716; p < 0.001). After a single treatment session, a mean 90 ± 13% volume shrinkage was achieved in all 23 OVM. The mean Hertel exophthalmometry decreased significantly from 14 ± 3 to 13 ± 1 mm (t = 2.515; P < 0.02). The resolution of periocular dyschromasia and swelling were evident in 20 patients (87%). Symptom scores improved significantly from 6.5 ± 1.4 (very intense discomfort or effect on daily living) to 1.2 ± 1.0 (very mild discomfort or effect on daily living; p < 0.001). Short-term bruises and swelling were reported in 20 patients (87%). CONCLUSION: Intralesional laser pretreatment is effective to facilitate surgery especially for the deep involving orbital venous malformations.