Maximum Radius Research Articles

A comparative study on the maximum mass and radius of anisotropic compact stars from Heintzmann geometry and the TOV approach

In this paper, a class of anisotropic compact stars is analyzed in Heintzmann geometry. The Einstein field equations (EFEs) have been solved to obtain the stellar model in presence of pressure anisotropy. We have considered the [Formula: see text] metric component as proposed by Heintzmann, and by solving the EFEs, the [Formula: see text] metric component is evaluated in the presence of pressure anisotropy. It is noted that for an isotropic star ([Formula: see text]), the maximum mass lies within the range 1.87–3.04[Formula: see text] for radii ranging between 8–13[Formula: see text]km. For anisotropic compact stars, the maximum mass increases with [Formula: see text] and lies within the range 1.99–3.23 [Formula: see text] for anisotropy parameter [Formula: see text]. The physical viability of the model is examined by applying our model to study the properties of a few known compact objects. All the stability conditions are fulfilled in the proposed model. It is also interesting to note that the maximum mass calculated from our model from geometrical consideration and solving the TOV equation is approximately equal, and the radii predicted from the present model comply with the estimated radius from observations of recently observed pulsars and lighter compact objects of GW events such as GW 190814 and GW 170817.

A packing problem approach to grasping with a two-finger gripper with application in forest harvesting

Robotic Hand Grasping is a challenging task that is studied by different researchers, with contributions made to topics such as grasping quality measuring, synthesis, and mathematical models. However, these works usually consider grasping of only one object at time, which is not applicable when the hand must carry multiple objects. Multiple objects grasping problem can be approached as a packing problem, which consists in filling a container with objects of a determined geometry, using the space available in the most efficient way. The aim of this work is to obtain a design methodology for a two-finger gripper that optimizes the grasping capacity of slender cylindrical multiple objects, applying packing problem concepts. This case is of practical importance in grapple claws used in forest harvesting for picking logs. A mathematical model is presented that allows to obtain an optimized geometric configuration of the grapple claw for maximum grasping capacity and packing density for given numbers and sizes of logs. This model is analytically solved for the maximum radius of a set of logs that can be grasped. Alternatively, for a number of logs with a given diameter, the geometric dimensions of an optimized grapple claw can be obtained. The solutions are evaluated using packing density and Active Force Closure (AFC) as quality metrics, to show the benefits of adding them as design criteria in the design multiple objects grapple claws.

Dynamic behaviors of concrete gravity dam against combined blast wave and bubble pulsation of underwater explosion

Underwater explosion process mainly includes the preceding blast wave and the succeeding bubble pulsation, while the effect of bubble pulsation on hydraulic structures is always neglected. This paper aims to numerically study the dynamic behaviors of prototype concrete gravity dam against underwater explosion, considering the combined effects of blast wave and bubble pulsation. Firstly, a finite element analysis (FEA) approach for predicting the underwater explosion loadings, as well as the damage evolution and dynamic responses of dam against underwater explosions was proposed, in which the hydrostatic pressure of reservoir and the dead load of dam were considered. Based on Cole's formula and the existing underwater explosion tests, the reliability of FEA approach, including the mesh sizes, material models and the corresponding parameters, as well as the mapping, Fluid-Structure Interaction and contact algorithms, was comprehensively validated. Secondly, to realize the simulation of the prototype gravity dam impeded by the validated small Lagrange mesh size, a mesh transition strategy was proposed based on the equivalence of dam damage modes and total eroded element mass. Finally, the dynamic behaviors of a typical 120 m-height concrete gravity dam against underwater explosion, i.e., 1 t of TNT equivalence detonated at a depth of 35 m and standoff distances of 4–16 m, were examined. The dimensionless distance λR, i.e., the ratio of the standoff distance to the maximum bubble radius, was introduced to quantitatively evaluate the underwater explosion loadings and dynamic behaviors of the dam. It indicates that, the blast wave firstly leads to the local compressive damage on the upstream surface, as well as the tensile damage on the downstream folded slope and dam heel. The succeeding free vibration and bubble pulsation will further aggravate the damage degree, resulting in the cracking of dam neck and heel. Especially for the scenarios when λR ≤ 1.22, the overall sliding of dam is highly prone to occur.

Introducing dusty plasma particle growth of nanospherical titanium dioxide

In dusty plasma environments, spontaneous growth of nanoparticles from reactive gases has been extensively studied for over three decades, primarily focusing on hydrocarbons and silicate particles. Here, we introduce the growth of titanium dioxide, a wide bandgap semiconductor, as dusty plasma nanoparticles. The resultant particles exhibited a spherical morphology and reached a maximum monodisperse radius of 235 ± 20 nm after growing for 70 s. The particle grew linearly, and the growth displayed a cyclic behavior; that is, upon reaching their maximum radius, the largest particles fell out of the plasma, and the next growth cycle immediately followed. The particles were collected after being grown for different amounts of time and imaged using scanning electron microscopy. Further characterization was carried out using energy dispersive x-ray spectroscopy, x-ray diffraction, and Raman spectroscopy to elucidate the chemical composition and crystalline properties of the maximally sized particles. Initially, the as-grown particles exhibited an amorphous structure after 70 s. However, annealing treatments at temperatures of 400 and 800 °C induced crystallization, yielding anatase and rutile phases, respectively. Annealing at 600 °C resulted in a mixed phase of anatase and rutile. These findings open avenues for a rapid and controlled growth of titanium dioxide via dusty plasma.

Characteristics of evolution and collapse in spark-induced cavitation bubbles

Numerous scientists have thoroughly researched cavitation bubble dynamics using experimental methods such as tube arrest, underwater discharge, ultrasound, and laser focusing. In this study, with the aid of high-speed photography, the formation mechanism of the electrode-contact spark-induced cavitation bubble is discovered, i.e., electrolysis results in non-condensable gases wrapping the small inter-electrode gaps, and the non-condensable gases are broken down by discharge to form plasma, which then induces the cavitation bubble. Since the cavitation bubbles already contain a certain amount of non-condensable gases during the discharge process, the differences in the spatiotemporal evolution and collapse characteristics of the cavitation bubbles with varying amounts of non-condensable gases are further analyzed. The results show that underwater electrode-contact discharge system has an optimal voltage if the capacitance and discharge electrode size remain constant, and the cavitation bubbles generated under the optimal voltage condition are not only morphologically closest to the laser-induced cavitation bubbles, but also the change in radius over time during collapse is quite consistent with the Rayleigh bubble. Furthermore, compared to cavitation bubbles generated under varying voltages, those induced by the optimal voltage have a lower amount of non-condensable gases. This leads to the minimum first contraction radius and the maximum rebound radius being close to the corresponding values of the laser-induced cavitation bubbles. These new findings are of great significance for the improvement of experimental technology in the study of cavitation bubble dynamics, obtaining precise and dependable experimental data, and validating numerical simulations.

Experimental investigation on the interaction of spark-generated array bubbles near a rigid wall

This study experimentally investigates the interaction of an array of bubbles near a rigid wall. Three bubbles are simultaneously generated using underwater electric discharges, forming a linear alignment with approximately equal sizes. A high-speed camera was used to record the evolution of the bubbles, with the pressure sensors placed on the surface of the rigid wall to measure the pressure resulting from both the jet and collapse of the bubbles. The results demonstrate that the behavior of the array bubbles, including collapse, jetting, and coalescence, is significantly influenced by the dimensionless distances Ra = da/Rm and Rh = dh/Rm (where Rm is the maximum bubble radius, and da and dh represent the inter-bubble distance and bubble-wall distance, respectively). A series of experiments, designed with various Ra and Rh, were conducted to systematically investigate the behaviors of the bubbles and their resulting pressure characteristics on the central of the wall. This research aims to offer a practical reference for understanding interacting array bubbles and the potential pressure threats to nearby structures.

In Silico Coformer Screening for Mefenamic Acid Cocrystallization

Cocrystallization is a widely used approach to enhance the solubility and dissolution characteristics of poorly soluble drugs. A pharmaceutical cocrystal is a multicomponent system composed of a solid active pharmaceutical ingredient (API) and a coformer, governed by non-covalent interactions. Screening for suitable coformers is essential to obtain an optimal cocrystal for specific drugs. This study aims to determine the drug-coformer interactions to select the most suitable coformer for cocrystal formation using the molecular docking method. Mefenamic acid, classified as a class II drug in the biopharmaceutical classification system (BCS), was used as the model drug. Two-dimensional structures of mefenamic acid (PubChem CID: 4044) and potential coformers were sourced from PubChem. Geometric optimization of all compounds was performed using GaussView 5.0.8 and Gaussian09 with the 3-21G basis set and Density Functional Theory (DFT) B3LYP method. The optimized compounds were prepared by adding hydrogen atoms and calculating Kollman partial charges using AutoDock 4.2. A grid box of size 40 Å × 40 Å × 40 Å was generated, with a maximum radius of 0.375 Å set as the surface distance in each simulation. A hundred conformations were run using the Lamarckian Genetic Algorithm. Interaction types and binding energies were analyzed using VMD 1.9.2 and BIOVIA Discovery Studio 2020 to compare interactions between mefenamic acid and each coformer. The results revealed that most coformer compounds formed interactions with mefenamic acid via hydrogen bonding and π–interactions. Saccharin demonstrated the most optimal interaction with mefenamic acid, with a binding free energy of –3.1 kcal/mol. Saccharin was identified as the most suitable coformer for mefenamic acid cocrystal formation based on the molecular docking study. Further experimental validation of saccharin is recommended to confirm its effectiveness in cocrystallization with mefenamic acid.

Extremal values for the spectral radius of the normalized distance Laplacian

The normalized distance Laplacian of a graph G is defined as DL(G)=T(G)−1/2(T(G)−D(G))T(G)−1/2 where D(G) is the matrix with pairwise distances between vertices and T(G) is the diagonal transmission matrix. In this project, we study the minimum and maximum spectral radii associated with this matrix, and the structures of the graphs that achieve these values. In particular, we prove a conjecture of Reinhart that the complete graph is the unique graph with minimum spectral radius, and we give several partial results towards a second conjecture of Reinhart regarding which graph has the maximum spectral radius.

Control System UV-C Lamp and Room Temperature Based Internet of Things

At the beginning of 2020, the world was shocked by the emergence of a new virus, Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-nCoV- 2) and the name of the disease is Coronavirus Disease 2019 (COVID-19). Common symptoms of COVID-19 are acute respiratory distress, fever, cough and shortness of breath. One of the efforts to overcome the transmission of COVID-19 is by sterilizing the room. This research designs an automatic room sterilization device using UV-C lamps that can be controlled using the Blynk application. There are 2 working principles of this tool, namely automatic, the lamp will turn on according to a predetermined setpoint and manual, the lamp will turn on manually like a normal lamp. Hardware used to make this tool are NodeMCU ESP8266, DHT11 sensor, PIR sensor, UV-C lamp, and Relay. As for the software used are Arduino IDE and Blynk Application. This research has 3 tests, the first is testing the lamp automation system where the UV-C lamp response is in accordance with the notification in the Blynk application. The second test is a human detection system with a PIR sensor where the sensor can detect with a maximum radius of 5m. The third test of room temperature monitoring system with DHT11 sensor with digital thermometer comparison tool. The average error value is 0.88% with the accuracy of the DHT11 sensor of 99.12%

Superparamagnetic iron oxide nanoparticle enhanced percutaneous microwave ablation: Ex-vivo characterization using magnetic resonance thermometry.

Percutaneous microwave ablation (pMWA) is a minimally invasive procedure that uses a microwave antenna placed at the tip of a needle to induce lethal tissue heating. It can treat cancer and other diseases with lower morbidity than conventional surgery, but one major limitation is the lack of control over the heating region around the ablation needle. Superparamagnetic iron oxide nanoparticles have the potential to enhance and control pMWA heating due to their ability to absorb microwave energy and their ease of local delivery. The purpose of this study is to experimentally quantify the capabilities of FDA-approved superparamagnetic iron oxide Feraheme nanoparticles (FHNPs) to enhance and control pMWA heating. This study aims to determine the effectiveness of locally injected FHNPs in increasing the maximum temperature during pMWA and to investigate the ability of FHNPs to create a controlled ablation zone around the pMWA needle. PMWA was performed using a clinical ablation system at 915MHz in ex-vivo porcine liver tissues. Prior to ablation, 50uL 5mg/mL FHNP injections were made on one side of the pMWA needle via a 23-gauge needle. Local temperatures at the FHNP injection site were directly compared to equidistant control sites without FHNP. First, temperatures were compared using directly inserted thermocouples. Next, temperatures were measured non-invasively using magnetic resonance thermometry (MRT), which enabled comprehensive four-dimensional (volumetric and temporal) assessment of heating effects relative to nanoparticle distribution, which was quantified using dual-echo ultrashort echo time (UTE) subtraction MR imaging. Maximum heating within FHNP-exposed tissues versus control tissues were compared at multiple pMWA energy delivery settings. The ability to generate a controlled asymmetric ablation zone using multiple FHNP injections was also tested. Finally, intra-procedural MRT-derived heat maps were correlated with gold standard gross pathology using Dice similarity analysis. Maximum temperatures at the FHNP injection site were significantly higher than control (without FHNP) sites when measured using direct thermocouples (93.1±6.0°C vs. 57.2±8.1°C, p=0.002) and using non-invasive MRT (115.6±13.4°C vs. 49.0±10.6°C, p=0.02). Temperature difference between FHNP-exposed and control sites correlated with total energy deposition: 66.6±17.6°C, 58.1±8.5°C, and 20.8±9.2°C at high (17.5±2.2kJ), medium (13.6±1.8kJ), and low (8.8±1.1kJ) energies, respectively (all pairwise p<0.05). Each FHNP injection resulted in a nanoparticle distribution within 0.9±0.2cm radially of the injection site and a local lethal heating zone confined to within 1.1±0.4cm radially of the injection epicenter. Multiple injections enabled a controllable, asymmetric ablation zone to be generated around the ablation needle, with maximal ablation radius on the FHNP injection side of 1.6±0.2cm compared to 0.7±0.2cm on the non-FHNP side (p=0.02). MRT intra-procedural predicted ablation zone correlated strongly with post procedure gold-standard gross pathology assessment (Dice similarity 0.9). Locally injected FHNPs significantly enhanced pMWA heating in liver tissues, and were able to control the ablation zone shape around a pMWA needle. MRI and MRT allowed volumetric real-time visualization of both FHNP distribution and FHNP-enhanced pMWA heating that was useful for intra-procedural monitoring. This work strongly supports further development of a FHNP-enhanced pMWA paradigm; as all individual components of this approach are approved for patient use, there is low barrier for clinical translation.

The Role of the Peak Radius of Maximum Wind Contraction Rate Preceding the Peak Intensification Rate on Tropical Cyclone Lifetime Maximum Intensity

AbstractThe prevalence of the maximum radius of maximum wind (RMW) contraction rate for the tropical cyclone (TC) before the maximum TC intensification rate has been observed in several previous studies. However, it remains unclear whether and how the maximum RMW contraction rate preceding the maximum TC intensification rate affects the TC lifetime maximum intensity (LMI). In this study, tropical cyclones are grouped into three types depending on whether the peak RMW contraction rate precedes, occurs simultaneously with, or lags the time of the peak intensification rate in the North Atlantic and western North Pacific. Results indicate that when the maximum RMW contraction rate occurs before the maximum intensification rate, TCs are more likely to gain a greater LMI. TCs with the time of maximum RMW contraction rate preceding the time of the maximum intensification rate are more likely to achieve a small RMW and intermediate intensity after the maximum RMW contraction rate period, which is conducive to higher intensification rates. An intermediate initial intensity and higher maximum intensification rate both lead to a greater LMI. Environmental factors are also examined but are found to have little impact on the LMI for the three types of TCs. This work suggests that TCs with a higher LMI are often characterized by a notable maximum rate of RMW contraction before the peak intensification rate and helps to a better understanding of TC structure and intensity changes.

Crater radius analysis after dual droplets successive oblique impact on liquid film

Droplet impact is a common occurrence in nature, agriculture, and industry. The research on the multi‐droplet impact is fundamental to understanding the tangled nature of reality. This paper numerically studies the successive oblique impact of dual droplets on the liquid film by building an effective three‐dimensional model. The leading and trailing droplets are set to pass a certain impact point with the same velocity. The main contribution of this paper is the investigation of the effects of Weber number, liquid film thickness, impact angle, and impact time interval on the interface morphology evolution after the droplet impact. Results show that splash pattern conversion of the primary or secondary crown occurs with the change of these factors. Besides, the variations of the maximum crater radius in upstream, lateral, and downstream directions with time are quantitatively analyzed. The crater radius analysis is carried out from three perspectives, the variation during the single droplet impact, the change during the dual droplets impact, and the comparison between them. It is found that the crater of dual droplets impact exhibits shape distortion in the deformation period and appears a marked dimensional increase in the secondary expansion period.

Exploring the Distribution and Impact of Bosonic Dark Matter in Neutron Stars

The presence of dark matter (DM) within neutron stars (NSs) can be introduced by different accumulation scenarios in which DM and baryonic matter (BM) may interact only through the gravitational force. In this work, we consider asymmetric self-interacting bosonic DM, which can reside as a dense core inside the NS or form an extended halo around it. It is seen that depending on the boson mass (mχ), self-coupling constant (λ) and DM fraction (Fχ), the maximum mass, radius and tidal deformability of NSs with DM admixture will be altered significantly. The impact of DM causes some modifications in the observable features induced solely by the BM component. Here, we focus on the widely used nuclear matter equation of state (EoS) called DD2 for describing NS matter. We show that by involving DM in NSs, the corresponding observational parameters will be changed to be consistent with the latest multi-messenger observations of NSs. It is seen that for mχ≳200 MeV and λ≲2π, DM-admixed NSs with 4%≲Fχ≲20% are consistent with the maximum mass and tidal deformability constraints.

Characterization of acoustic droplet vaporization in tissue-mimicking, fibrin-based hydrogels for microrheology applications

Ultrasound-induced vaporization of phase-shift droplets (PSDs) into microbubbles, termed acoustic droplet vaporization (ADV), has expanded biomedical applications. Here, we explored the potential of ADV as a high-resolution, on-demand microrheometer using theoretical and experimental methodologies. This approach could be used to characterize tissue elasticity at spatial resolutions unrealizable with conventional in situ techniques, thus assisting with identification of underlying pathologies. For theoretical studies, bubble dynamics were combined with appropriate material constitutive models accounting for viscoelasticity of the surrounding tissue. Experiments were conducted on submicron- and micron-sized, perfluoropentane PSDs embedded in fibrin-based hydrogels with varying shear elastic moduli (0.2 kPa–11 kPa) to mimic soft tissues. Experimental studies included optical high-speed imaging and acoustic interrogations to record radial dynamics and acoustic emissions of the ADV-bubbles, respectively. Radial dynamics and the acoustic emissions of microbubbles produced by ADV depended significantly on fibrin elasticity. For example, an increase in fibrin elastic modulus from ∼0.8 kPa to ∼6 kPa reduced the maximum expansion radius of the generated ADV-bubbles by 50%. This increase in elasticity significantly impacted both linear (e.g., fundamental) and nonlinear (e.g., subharmonic) acoustic responses of the ADV-bubbles, by up to 15 dB. These findings open doors to a novel ADV-assisted tissue characterization technique.

Effect of Surface Renewal on the Drop Size Distribution in Dropwise Condensation within a Hybrid Surface

The description of liquid drop growth and drop distribution are two key models in evaluating the thermal performance of dropwise condensation (DWC) heat transfer. The drop size distribution describes the growth process of small drops by direct condensation and large drops by coalescence. The present work investigates the effect of surface renewal and coalescence intensities of DWC within a hybrid surface. Additionally, it examines the validity of the current empirical expression of the drop size distribution that is developed for DWC without considering surface renewal and coalescence intensities. The simulation work illustrates the drop growth process and surface renewal as drops depart and merge with neighboring film regions. The simulation results show that in hybrid DWC, the area fraction occupied by drops (f) lies between 0.28 to 0.296 for the ratio of maximum drop diameter to DWC region width (RD) from 0.125 to 1 and a total temperature drop (∆T) of 2, 4, and 8 ℃. Thus, the drop population is less sensitive to RD, and an average f of 0.288 is generalized. On the other hand, the surface renewal for DWC within the hybrid surface shows improvement for RD &gt; 0.5 with the highest enhancement of 64 to 85% taking place at RD = 1, mainly due to the merging effect. In addition, results for drop size distribution profiles of DWC within the hybrid surface are characterized by a lower population of large drops and a higher population of small drops than full DWC. Additionally, the constant exponent (n) in the literature’s empirical expression is replaced by a polynomial series as a function of drop effective and maximum radii. The impact of surface renewal on coalescence intensity is presented in a relatively steeper slope on the logarithmic scale.

Modern software capabilities for shape optimization of shells

The article is devoted to the shape optimization of shell structures in Comsol Multiphysics using three gradient-based methods: IPOPT (Interior Point OPTimizer), SNOPT (Sparse Nonlinear OPTimizer) and MMA or GCMMA (the Method of Moving Asymptotes). Two types of complex shapes, such as right helicoid and developable helicoid are taken for the computational experiment. The task is to investigate the initial design and optimization process of two helicoids. To obtain a more accurate result and an interesting design solution, the calculation is carried out using three physics-controlled mesh sizes: extra coarse, fine and extra fine with varying values of special optimization settings, such as maximum displacement (dmax) and filter radius (Rmin). The results obtained using the three methods allow to conclude that the mesh element size and studied parameters dmax and Rmin have a significant impact on the final optimization result.

Superhydrophobic composite membranes for membrane distillation based on CNTs networks: Overcoming the trade-off between water vapor permeability and wetting resistance

Enhancing the wetting resistance of the membrane is crucial for consolidating the stability of the membrane distillation (MD) process, but this generally leads to the decline of water vapor flux. Herein, we developed a superhydrophobic composite membrane composed of a highly hydrophobic polyvinylidene fluoride (PVDF) porous support layer and a functional superhydrophobic carbon nanotubes (CNTs) network. The CNTs network with high thermal conductivity not only reduces the temperature polarization effect, but also increases the effective evaporation area, thereby enhancing the mass transfer driving force of the MD process. Additionally, the CNTs network significantly reduces the maximum pore radius of the composite membrane, and the perfluorination treatment also reduces the surface energy of the CNTs network, thereby synergistically increasing the liquid entry pressure. The results showed that when treating high salinity water containing 3.5 wt% NaCl, the water vapor flux of the composite membrane increased from 20.0 LMH of the original PVDF membrane to 24.4 LMH, an increase of 22 %. Furthermore, the performance of the original PVDF membrane deteriorates rapidly when the concentration of surfactant in the feed exceeds 1.0 mM, while the composite membrane still maintains a stable water vapor permeability and salt rejection. More importantly, the composite membrane exhibits excellent resistance to wetting induced by gypsum scaling when using gypsum solution as the feed, which is attributed to its small surface pore size and high hydrophobicity. This research supplies new insights into the design of membrane structures used in MD processes to overcome the trade-off between water vapor permeability and wetting resistance.

Effect of Antagonists and Botanicals Against Xanthomonas oryzae pv. oryzae In Vitro

The present study was conducted during kharif (July-November, 2020) at the Department of plant pathology, N. M. College of Agriculture, Navsari Agricultural University, Navsari, Gujarat (396 450), India to examine the efficacy of four recognized antagonists and a control against Xanthomonas oryzae pv. oryzae. By employing paper disc method the results indicated that Bacillus subtilis exhibited the highest radius of inhibition. Following this, Pseudomonas fluorescens, Trichoderma harzianum and Trichoderma viride were identified as the next most effective antagonists. In addition, ten different botanical extracts, including a control, were examined for their inhibitory impact on the bacterial growth of bacterial blight at a 5% concentration using the poisoned food technique. Among these extracts, garlic clove extract demonstrated the maximum inhibition radius against the pathogen, followed by tulsi leaf extract and neem leaf extract, attributed to potent toxic principles. Conversely, extracts from karanj, nilgiri, dhatura, jetropha and rhizomes of ginger, turmeric and onion bulb were found to be less effective against Xanthomonas oryzae pv. oryzae. The goal of this study provided valuable insights to determine the potential antagonists and botanicals against bacterial blight of rice in vitro with experimental design of Completely Randomized Design which offer a cost effective solution for the disease, in increasing crop yield to the rice growing farmers of Gujarat without disturbing ecosystem and without creating the problems of pollution.

Amelioration of oxygen-induced retinopathy in neonatal mice with fetal growth restriction.

Introduction: With the aim of optimizing the balance of maintaining a safe oxygen saturation and reducing the risk of retinopathy of prematurity in human neonates with fetal growth restriction (FGR), the present study investigated the distinct effects of oxygen supplementation on the retinal neovasculature using a murine premature neonatal oxygen-induced retinopathy (OIR) model with or without fetal growth restriction. Methods: For comparison with normal birth-weight neonates, maternal low-protein diet-induced FGR neonates were subjected to fluctuating oxygen levels to generate oxygen-induced retinopathy. The retinal neovasculature was histologically evaluated, and comprehensive transcriptome analysis was conducted. Results: Compared to OIR neonates with normal birth weight, significant amelioration of the neovasculature, as indicated by decreases in the number of branch junctions, vascular distribution, maximal vascular radius and microaneurysm-like tufts, was observed in OIR mice with FGR. The results of retinal RNA-sequencing revealed downregulation of angiogenic factors that trigger pathological retinal neovascularization, such as the mitogen-activated protein kinase pathway and corresponding upstream signaling pathways in OIR mice with FGR. Conclusion: Our findings demonstrated that FGR neonates have a higher capacity for retinal oxygen stress, and the risk of OIR development is attenuated compared to that in mature neonates with normal birth weight.

Neutron Star in Quantized Space-Time

We construct and analyze a model of a neutron star in a κ-deformed space-time. This is conducted by first deriving the κ-deformed generalization of the Einstein tensor, starting from the non-commutative generalization of the metric tensor. By generalizing the energy-momentum tensor to the non-commutative space-time and exploiting the κ-deformed dispersion relation, we then set up Einstein’s field equations in the κ-deformed space-time. As we adopt a realization of the non-commutative coordinates in terms of the commutative coordinates and their derivatives, our model is constructed in terms of commutative variables. Using this, we derive the κ-deformed generalization of the Tolman–Oppenheimer–Volkoff equation. Now, by treating the interior of the star as a perfect fluid as in the commutative space-time, we investigate the modification of the neutron star’s mass due to the non-commutativity of space-time, valid up to first order in the deformation parameter. We show that the non-commutativity of space-time enhances the mass limit of the neutron star. We show that the radius and maximum mass of the neutron star depend on the deformation parameter. Further, our study shows that the mass increases as the radius increases for fixed values of the deformation parameter. We show that maximum mass and radius increase as the deformation parameter increases. We find that the mass varies from 0.26M⊙ to 3.68M⊙ as the radius changes from 8.45 km to 18.66 km. Using the recent observational limits on the upper bound of the mass of a neutron star, we find the deformation parameter to be |a|∼10−44 m. We also show that the compactness and surface redshift of the neutron star increase with its mass.