Central Density Research Articles

Cloud Collision Signatures in the Central Molecular Zone

Molecular cloud collisions are a prominent theory for the formation of stars. Observational studies into cloud collisions identify the collision via a bridging feature: a continuous strip of line emission that connects two intensity peaks that are related in position space and separated in velocity space. Currently, most observations of collisions and these bridging features take place in the Milky Way disc. They are also theorized to take place in the Central Molecular Zone (CMZ), where temperatures and densities are both significantly higher than in the disc. For studies in the Milky Way Disc, the most commonly-used tracer tends to be CO. However, for studies in the CMZ, where the density and temperature are significantly higher, CO becomes so abundant that it loses its ability to adequately highlight the bridging feature of cloud collisions. As a result, studies have begun using other tracers, whose physical and chemical behavior has not been studied under CMZ conditions. We perform combined hydrodynamical, chemical and radiative transfer simulations of cloud collisions under both disc- and CMZ-like conditions, and investigate collision signatures in a number of commonly-observed molecular lines. Under the Milky Way disc conditions ( ) has the standard bridging feature; however, the other tracers, CS, HCO +, N 2H + only emit in the intermediate-velocity bridge region, making the feature itself non-existent. In the CMZ, the higher density and temperature make the bridging feature far more indistinct for CO, but the other tracers have morphologically similar bridging features to the CO disc model, validating their use as tracers of cloud collisions under these conditions.

On the Origin of Quenched but Gas-rich Regions at Kiloparsec Scales in Nearby Galaxies

We use resolved spectroscopy from MaNGA to investigate the significance of both local and global properties of galaxies to the cessation of star formation at kpc scales. Quenched regions are identified from a sample of isolated disk galaxies by a single-parameter criterion D n (4000) - log EW(Hα) >1.6−log2=1.3 , and are divided into gas-rich quenched regions (GRQRs) and gas-poor quenched regions according to the surface density of cold gas (Σgas). Both types of quenched regions tend to be hosted by non-AGN galaxies with relatively high mass (M * ≳ 1010 M ⊙) and red colors (NUV − r ≳ 3), as well as low star formation rate and high central density at fixed mass. They span wide ranges in other properties including structural parameters that are similar to the parent sample, indicating that the conditions responsible for quenching in gas-rich regions are largely independent of the global properties of galaxies. We train random forest classifiers and regressors for predicting quenching in our sample with 15 local/global properties. Σ* is the most important property for quenching, especially for GRQRs. These results strongly indicate the important roles of low-mass hot evolved stars, which are numerous and long-lived in quenched regions and can provide substantial radiation pressure to support the surrounding gas against gravitational collapse. The different feature importance for quenching, as found previously by A. F. L. Bluck et al., is partly due to the different definitions of quenched regions, particularly the different requirements on EW(Hα).

Impact of water vapor on the 2D MoS2 growth in metal-organic chemical vapor deposition

In the presented work, the method of metal–organic chemical vapor deposition (MOCVD) using Mo(CO)6 and H2S assisted by oxidative etching with water vapor, was employed for the synthesis of MoS2. This study was aimed at detailed investigation of the films' properties obtained via this method and identifying methods for elimination of such disadvantages as the carbon impurities and the small size of crystalline domains in the films. It was found that in the temperature range from 850 °C to 950 °C, the effect of water vapor on the morphology of MoS2 is significantly different. The study of the chemical states of molybdenum and sulfur made it possible to associate the size of the crystal domains formed with the efficiency of removing the oxidized states of Mo6+ and S6+. It is assumed that the increase in the domains’ size is due to rapid lateral growth, resulting from the complete removal of the oxidized states at the edges, as well as a decrease in the density of nucleation centers due to the etching of less stable seeds on the substrate surface.

Deflection of light by wormholes and its shadow due to dark matter within modified symmetric teleparallel gravity formalism

Abstract We explore the possibility of traversable wormhole formation in the dark matter halos in the context of $f(Q)$ gravity. We obtain the exact wormhole solutions with anisotropic matter source based on the Bose-Einstein condensate, Navarro-Frenk-White, and pseudo-isothermal matter density profiles. Notably, we present a novel wormhole solution supported by these dark matters using the expressions for the density profile and rotational velocity along with the modified field equations to calculate the redshift and shape functions of the wormholes. With a particular set of parameters, we demonstrate that our proposed wormhole solutions fulfill the flare-out condition against an asymptotic background. Additionally, we examine the energy conditions, focusing on the null energy conditions at the wormhole's throat, providing a graphical representation of the feasible and negative regions. Our study also examines the wormhole's shadow in the presence of various dark matter models, revealing that higher central densities result in a shadow closer to the throat, whereas lower values have the opposite effect. Moreover, we explore the deflection of light when it encounters these wormholes, particularly noting that light deflection approaches infinity at the throat, where the gravitational field is extremely strong.

Role of local anisotropy in hybrid stars

Using the Bower–Liang model, we discuss how pressure anisotropies affect the microscopic and macroscopic properties of hybrid stars. We find that anisotropies affect the maximum mass, central density, and radius of the canonical stars. Anisotropies also affect the minimum neutron star mass that presents quarks in their core, as well as the total amount of quarks for the maximally massive stars. We also confront our results with standard constraints, such as the radius and the tidal parameter of the canonical star, as well as the mass and radius of the PSR J0740+6620 pulsar. We observe that moderate values for anisotropies could fulfill these constraints simultaneously. On the other hand, within more extreme degrees of anisotropies, more speculative constraints such as black widow pulsars PSR J0952-0607 and the mass-gap object in the GW190814 event can be explained as hybrid stars. We also investigate the role of anisotropies in the neutron stars’ moment of inertia.

A core in a star-forming disc as evidence of inside-out growth in the early Universe

AbstractThe physical processes that establish the morphological evolution and the structural diversity of galaxies are key unknowns in extragalactic astrophysics. Here we report the finding of the morphologically mature galaxy JADES-GS+53.18343−27.79097, which existed within the first 700 million years of the Universe’s history. This star-forming galaxy with a stellar mass of 400 million solar masses consists of three components: a highly compact core with a half-light radius of less than 100 pc, an actively star-forming disc with a radius of about 400 pc and a star-forming clump, all of which show distinctive star-formation histories. The central stellar mass density of this galaxy is within a factor of 2 of the most massive present-day ellipticals, while being globally 1,000 times less massive. The radial profile of the specific star-formation rate is rising towards the outskirts. This evidence suggests a detection of the inside-out growth of a galaxy as a proto-bulge and a star-forming disc in the epoch of reionization.

Reduction of neoclassical bulk-ion transport to avoid helium-ash retention in stellarator reactors

Abstract The reduction of neoclassical energy transport in stellarators has traditionally focussed on optimizing magnetic fields for small values of ‘effective helical ripple’ — ϵ eff , the geometric factor associated with electron 1 / ν transport—and relying on the radial electric field, E r , needed to maintain ambipolarity in the plasma, to simultaneously diminish ion energy losses to a tolerable level. As one must generally expect E r < 0 , such a strategy has a drawback for reactor operation, however, as negative values of E r tend to hinder the exhaust of helium ash, and this will become intolerable if it results in excessive fuel dilution. Theoretically, one can show that the neoclassical transport of low-Z impurities depends critically on the ratio L 11 e / L 11 i , where the L 11 σ are the neoclassical particle diffusion coefficients of the bulk-plasma electrons ( σ = e ) and ions ( σ = i ). Increasing the value of this ratio is shown here to counteract impurity retention, but maintaining good confinement of the bulk species requires this to be achieved by decreasing L 11 i rather than increasing L 11 e , implying the need for more than just minimization of ϵ eff in reactor design. To assess the prospects of such an endeavor, a predictive 1-D transport code is used here to determine the range of L 11 e / L 11 i values which arises in simulations of conventionally optimized reactor candidates. This range is found to be considerable, and includes examples with L 11 e / L 11 i values large enough to provide neoclassical temperature screening of the helium ash and even to flip the sign of the neoclassical convective velocity from inward- to outward-directed. More intriguingly, the strong reduction of L 11 i in such cases can also lead to the appearance of E r > 0 (a so-called ‘electron root’) within the core of plasmas having central densities as large as 2 × 10 20 m−3. Having E r > 0 in the plasma core produces the ideal situation in which all thermodynamic forces aid in the exhaust of helium ash, although this benefit is tempered by the small values of L 11 z which accompany an electron root (where σ = z denotes helium ash). Means are discussed for improving the results presented here, so that avoiding helium-ash retention can be explicitly targeted in future reactor optimizations.

Correlations between dyslipidemia and retinal parameters measured with Angio-OCT in type II diabetics without diabetic retinopathy.

To analyze the relationship between lipoproteins such as total cholesterol, LDL-c, TG, and retinal parameters in patients with DM type II without signs of DR. A case-control study, consisting of 2 groups. A group of 64 patients with type II diabetes without signs of DR and a control group of 24 healthy subjects. Patients with DM type I, those who showed signs of DR, and those who had associated other eye diseases were excluded. The patients of the two studied groups had a similar average age: 65 years in the DM type II group and 64 years in the control group. In the group with DM, the average CRT was 241.31 µm, a significantly lower value compared to the control group, 252.51. The average value of DVFC was 19.19%, in patients with DM and 24.29% in the control group. An indirect correlation with moderate intensity was established between total cholesterol and CRT, (rs=-0.442, p≤0.001), thus it tended to decrease as total cholesterol increased. With increasing total cholesterol level, DVFC had a mild tendency to decrease (rs=-0.381, p≤0.001). An indirect correlation, but weak in intensity, existed between the LDL/HDL ratio and the DVFC S value (rs=-0.240, p=0.001). Central retinal thickness and central vascular density of the superficial capillary plexus were significantly lower in patients with type II diabetes, compared to control subjects. Total cholesterol had higher values in the DM group and an indirect correlation was established with CRT and DVFC, these having a moderate tendency to decrease as the total cholesterol values increased. An indirect and moderate relationship in intensity was also present between LDL and retinal parameters studied. These results were similar to those of other studies conducted, such as that of Chen et al. or Bernaous et al., who showed an association between various lipid classes and the frequency of DR. However, other studies, such as Ausdiab, found that this association did not hold. Type II diabetes patients tend to have elevated serum lipid levels compared to normal subjects, but the impact of dyslipidemia on the onset and progression of DR is incompletely elucidated.

Investigating the exciton dynamics in InGaN/GaN core-shell nanorods using time-resolved cathodoluminescence.

This study examines the exciton dynamics in InGaN/GaN core-shell nanorods using time-resolved cathodoluminescence (TRCL), which provides nanometer-scale lateral spatial and tens of picoseconds temporal resolutions. The focus is on thick (>20 nm) InGaN layers on the non-polar, semi-polar and polar InGaN facets, which are accessible for study due to the unique nanorod geometry. Spectrally integrated TRCL decay transients reveal distinct recombination behaviours across these facets, indicating varied exciton lifetimes. By extracting fast and slow lifetime components and observing their temperature trends along with those of the integrated and peak intensity, the differences in behaviour were linked to variations in point defect density and the degree and density of localisation centres in the different regions. Further analysis shows that the non-polar and polar regions demonstrate increasing lifetimes with decreasing emission energy, attributed to an increase in the depth of localisation. The semi-polar facet instead showed a spectral independence of the lifetime which could not be rationalised by an absence of exciton localisation. This investigation provides insights into the intricate exciton dynamics in InGaN/GaN nanorods, offering valuable information for the design and development of optoelectronic devices.

First integrated core-edge fluid simulation of ITER’s Limiter–Divertor transition with SolEdge-HDG

This work explores the Limiter–Divertor transition (L–D) during the current ramp-up of ITER’s Q = 10 baseline plasma scenario at various central line-integrated density nli values. The analysis, based on transport simulations performed with the latest version of SoleEdge-HDG, focuses on the time evolution of heat and ion particle fluxes, revealing regions of elevated temperature on the inner wall and plasma-facing components (PFCs) despite moderate loads. The investigation also delves into the effects of perpendicular convection flux terms on density build-up, comparing different formulations and their interplay with auxiliary heating sources. Furthermore, the paper shows the impact of taking into account the evolution of the parallel neutral momentum on plasma and neutral density at the targets in the context of an ITER steady-state scenario.

JWST Reveals Bulge-dominated Star-forming Galaxies at Cosmic Noon

Hubble Space Telescope imaging shows that most star-forming galaxies at cosmic noon—the peak of cosmic star formation history—appear disk-dominated, leaving the origin of the dense cores in their quiescent descendants unclear. With the James Webb Space Telescope’s high-resolution imaging to 5 μm, we can now map the rest-frame near-infrared emission, a much closer proxy for stellar mass distribution, in these massive galaxies. We selected 70 star-forming galaxies with 10 < log(M) < 12 and 1.5 < z < 3 in the CEERS survey and compare their morphologies in the rest-frame optical to those in the rest-frame near-IR. While the bulk of these galaxies are disk-dominated in 1.5 μm (rest-frame optical) imaging, they appear more bulge-dominated at 4.4 μm (rest-frame near-infrared). Our analysis reveals that in massive star-forming galaxies at z ∼ 2, the radial surface brightness profiles steepen significantly, from a slope of ∼0.3 dex−1 at 1.5 μm to ∼1.4 dex−1 at 4.4 μm within radii <1 kpc. Additionally, we find their total flux contained within the central 1 kpc is approximately 7 times higher in F444W than in F150W. In rest-optical emission, a galaxy’s central surface density appears to be the strongest indicator of whether it is quenched or star-forming. Our most significant finding is that at redder wavelengths, the central surface density ratio between quiescent and star-forming galaxies dramatically decreases from ∼10 to ∼1. This suggests the high central densities associated with galaxy quenching are already in place during the star-forming phase, imposing new constraints on the transition from star formation to quiescence.

Identifikasi Lokasi Pemusatan Fasilitas Rumah Sakit Kota di Surakarta

Health is the optimal general state of one's body, mind, and spirit. Someone can do an activity because there is a healthy body so in general everyone always tries to stay healthy. The availability and convenience of health facilities is one of the efforts made by the government to improve the quality of public health. The purpose of this study with the Mean center method and Density estimation analysis with Heatmap, is to gain a better understanding of data distribution patterns. The Mean center method is used to determine the central point of distribution of data which can then be used as a reference to analyze and understand further distribution patterns. From this analysis it can be concluded that the Mean center method can help in identifying the center point or midpoint in the Surakarta area, describing the ideal location in Surakarta City, this method allows geographical representation of the center point using geographical coordinates such as latitude and longtitude which can then provide an easy understanding of the relative location of the center point of the hospital to other hospitals in the region. The results of the Mean center show that the center point of the hospital is located in Kelurahan Kestalan, Kecamatan, Banjarsari Surakarta City. Density estimation results in 3 (three) concentration clusters in Surakarta City. This helps local governments in plans to add health facilities, because of the gap in the northern, central and southern regions.

Descemet Endothelial Thickness Comparison Trial II (DETECT II): multicentre, outcome assessor-masked, placebo-controlled trial comparing Descemet membrane endothelial keratoplasty (DMEK) to Descemet stripping only (DSO) with adjunctive ripasudil for Fuchs dystrophy

IntroductionIt remains uncertain whether Descemet membrane endothelial keratoplasty (DMEK) or Descemet stripping only (DSO) yields better outcomes in patients with symptomatic Fuchs endothelial corneal dystrophy (FECD). This paper presents the...

The role of active galactic nucleus feedback on the evolution of dwarf galaxies from cosmological simulations

Aims. Recent observational studies suggest that feedback from active galactic nuclei (AGNs) may play an important role in the formation and evolution of dwarf galaxies, an issue that has received little attention from a theoretical perspective. Methods. We investigated this using two sets of 12 cosmological magnetohydrodynamic simulations of the formation of dwarf galaxies (108.3M⊙ ≤ M* ≤ 109.8M⊙): one set using a version of the AURIGA galaxy formation physics model including AGN feedback and a parallel set with AGN feedback turned off. Results. We show that the full-physics AGN runs satisfactorily reproduce several scaling relations, including the black-hole-to-stellar mass (MBH-M⋆), the black-hole-to-sigma (MBH-σ⋆), and the baryonic Tully-Fisher relation. We find that the global star formation (SF) of galaxies run with an AGN is reduced compared to the one in which the AGN has been turned off, suggesting that AGN feedback is a viable way of suppressing SF in dwarf galaxies, even though none of our galaxies is completely quenched by z = 0. Furthermore, we find a tight correlation between the median SF rates and the MBH/M⋆ ratio in our simulated dwarfs. Star formation is suppressed due to gas heating in the vicinity of the AGN: less HI gas is available in AGN runs, though the total amount of gas is preserved across the two settings within each galaxy. This indicates that the main effect of AGN feedback in our dwarfs is to heat up and push the gas away from the galaxy’s centre rather than expelling it completely. Finally, we show that the two galaxies harbouring the largest supermassive black holes have suffered a considerable (up to ∼65%) reduction in their central dark matter density, pinpointing the role of AGNs in determining the final dark matter mass distribution within dwarf galaxies. This pilot paper highlights the importance of modelling AGN feedback at the lowest mass scales and the impact this can have on dwarf galaxy evolution.

Effects of dark matter on the spontaneous scalarization in neutron stars

Dark matter, an important portion of compact objects, can influence different phenomena in neutron stars. The spontaneous scalarization in the scalar-tensor gravity has been proposed for neutron stars. Here, we investigate the spontaneous scalarization in dark matter admixed neutron stars. Applying the dark matter equations of state, we calculate the structure of scalarized neutron stars containing dark matter. The dark matter equations of state are based on observational data from the rotational curves of galaxies and the fermionic self-interacting dark matter. Our results verify that the spontaneous scalarization is affected by the dark matter pressure in neutron stars. Depending on the central density of scalarized dark matter admixed neutron stars, the dark matter pressure alters the central scalar field. The increase of dark matter pressure in low-density scalarized stars amplifies the central scalar field. However, the pressure of dark matter in high-density scalarized stars suppresses the central scalar field. Our calculations confirm that the stars in the merger event GW170817 and in the low-mass X-ray binary 4U 1820-30 can be scalarized dark matter admixed neutron stars.

Impact of ice growth on the physical and chemical properties of dense cloud cores

We investigated the effect of time-dependent ice growth on dust grains on the opacity and hence on the dust temperature in a collapsing molecular cloud core, with the aim of quantifying the effect of the dust temperature variations on ice abundances as well as the evolution of the collapse. To perform the simulations, we employed a one-dimensional collapse model that self-consistently and time-dependently combines hydrodynamics with chemical and radiative transfer simulations. The dust opacity was updated on the fly based on the ice growth as a function of the location in the core. The results of the fully dynamical model were compared against simulations run with different values of fixed ice thickness. We found that the ice thickness increases quickly and reaches a saturation value (as a result of a balance between adsorption and desorption) of approximately 90 monolayers in the central core (volume density ~104 cm−3), and several tens of monolayers at a volume density of ~103 cm−3, after only a few 105 yr of evolution. The results thus exclude the adoption of thin (approximately ten monolayer) ices in molecular cloud simulations except at very short timescales. However, the differences in abundances and the dust temperature between the fully dynamic simulation and those with a fixed dust opacity are small; abundances change between the solutions generally within a factor of two only. The assumptions on the dust opacity do have an effect on the collapse dynamics through the influence of the photoelectric effect on the gas temperature, and the simulations take a different time to reach a common central density. This effect is, however, small as well. In conclusion, carrying out chemical simulations using a dust temperature corresponding to a fixed opacity seems to be a good approximation. Still, although at least in the present case its effect on the overall results is limited – as long as the grains are monodisperse – ice growth should be considered to obtain the most accurate representation of the collapse dynamics. We have found in a previous work that considering a grain size distribution leads to a complicated ice composition that depends on the grain size nonlinearly. With this in mind, we will carry out a follow-up study where the influence of the grain size on the present simulation setup is investigated.

Association between Land Use and Urban Vitality in the Guangdong–Hong Kong–Macao Greater Bay Area: A Multiscale Study

Urban vitality, which indicates the development level of a city and the quality of life of its residents, is a complex subject in urban research due to its diverse assessment methods and intricate impact mechanisms. This study uses multisource data to evaluate the urban vitality of the Guangdong–Hong Kong–Macao Greater Bay Area (GBA) across social, economic, cultural, and environmental dimensions. It analyzes the spatial distribution characteristics of urban vitality and examines the relationships between urban vitality and land use at both regional and city scales. The results indicate that the urban vitality in the GBA generally exhibits a spatial distribution pattern of a high central density and a low peripheral spread, where built-up areas and cropland emerge as key influencing factors. Cities with different developmental backgrounds have unique relationships between land use and urban vitality. In high-vitality cities, the role of the built-up area diminishes, and natural ecosystems, such as wetlands, enhance vitality. In contrast, in low-vitality cities, built-up areas boost urban vitality, and agriculture-related land types exert a lower negative or even positive effect. This research contributes to the understanding of the spatial structures of urban vitality related to land use at different scales and offers insights for urban planners, builders, and development managers in formulating targeted urban vitality enhancement strategies at the regional collaborative and city levels.

Preliminary compact torus injection experiments on the Keda Torus eXperiment reversed field pinch

A new compact torus injector (KTX-CTI) has been built for injection experiments on the Keda Torus eXperiment (KTX) reversed field pinch (RFP). The aim is to study the fundamental physics governing the compact torus (CT) central fueling processes. In experiments conducted under the sole influence of a 0.1 T toroidal magnetic field, the injected CT successfully penetrated the entire toroidal magnetic field, reaching the inner wall of the KTX vacuum vessel. Upon reaching the inner wall, the CT diffused both radially outward and toroidally within the vessel at a discernible diffusion speed. Moreover, the inherent helicity within the CT induced a modest KTX plasma current of 200 A, consistent with predictions based on helicity conservation. CT injection demonstrated the capability to initiate KTX discharges at low loop voltages, suggesting its potential as a pre-ionization and current startup technique. During RFP discharges featuring CT injection, the central plasma density was found to exceed the Greenwald density limit, with more peaked density profiles, indicating the predominant confinement of CT plasma within the core region of the KTX bulk plasma.

Enhancement of peroxymonosulfate activation through regulating electronic structure of cobalt phthalocyanine by g-C3N4 for rhodamine B degradation

The catalytic performance of cobalt-based catalysts in Fenton-like reactions is significantly influenced by the electron density of Co centers. However, precise control of the electronic structure to enhance the degradation activity remains a challenge. This paper demonstrates a method to enhance the catalytic activity of cobalt phthalocyanine (CoPc) by modulating its electronic structure via integrating with graphitic carbon nitride (g-C3N4). The electron redistribution between g-C3N4 and CoPc was observed, resulting in electron-rich Co centers. Consequently, the CoPc/g-C3N4 composites exhibit significantly enhanced peroxymonosulfate (PMS) activation capability compared to CoPc and their physical mixtures. The improved catalytic performance is due to the electron-rich Co centers, better dispersion of CoPc, and enhanced hydrophilicity. This study proposes a novel strategy for the design of efficient PMS activation catalysts.

The impact of postoperative nasal oxygen therapy on early-stage corneal edema in cataract patients with dynamic Scheimpflug analyze: A retrospective study.

This study aimed to assess the impact of 6 hours of postoperative nasal oxygen therapy on early-stage corneal edema in patients with nuclear cataracts of grades 3 to 4. A retrospective study involved 49 patients (49 eyes) with grades 3 to 4 nuclear cataracts undergoing phacoemulsification and intraocular lens implantation from September 2021 to September 2022. The oxygen group (27 cases) received postoperative nasal oxygen therapy for 6 hours, while the control group (22 cases) received no additional treatment. Corneal edema was evaluated 24 hours postoperatively using a slit lamp microscope, recording the edema degree. The Pentacam anterior segment analyzer measured central corneal thickness (CCT), corneal volume (CV), and corneal optical density (COD) values preoperatively and 24 hours postoperatively. The study enrolled 49 patients. Preoperatively, there were no significant differences between the 2 groups. The oxygen group and the control group exhibited significant differences in CCT, CV, and corneal optical density values before and after surgery for intragroup comparison (all P < .05). At 24 hours postoperatively, the proportion of grade 0 corneal edema in the oxygen therapy group was 59.3%, compared to 31.8% in the control group, with no statistically significant difference (P > .05). The postoperative logMAR visual acuity in the oxygen therapy group was 0.0969 (0.0969, 0.2218), and in the control group it was 0.0969 (0.2218, 0.3979), with a statistically significant difference (P < .05). In oxygen group, the CCT, CV were 585.00 (553.00, 604.00), 68.0 (61.9, 71.3) respectively, all significantly lower than 603.50 (578.50, 788.25), 73.05 (65.3, 75.73) (all P < .05). Statistically significant differences were found in overall COD, COD within specific depth and thickness ranges, and COD within the anterior layer (120 μm thickness) at 24 hours postoperatively (all P < .05). No significant difference was observed in COD values within the central and posterior layers (60 μm thickness) between the 2 groups (all P > .05). Postoperative nasal oxygen therapy for 6 hours immediately after surgery could alleviate the severity of early-stage corneal edema in patients with nuclear cataracts of grades 3 to 4.