Change In Radius Research Articles

Treatment of Fracture-Related Infections with Bone Abscess Formation after K-Wire Fixation of Pediatric Distal Radius Fractures in Adolescents—A Report of Two Clinical Cases

Closed reduction and K-wire fixation of displaced distal radius fractures in children and adolescents is an established and successful surgical procedure. Fracture-related infections after K-wire fixation are rare but can have significant consequences for the patient. There is a lack of literature on the treatment of K-wire-associated fracture-related infections in children and adolescents. Herein, we report two cases of fracture-related infection after initial closed reduction and Kirschner wire fixation in two adolescents. One 13-year-old boy and one 11-year-old girl were seen for fracture-related infections 4 and 8 weeks after closed reduction and percutaneous K-wire fixation of a distal radius, respectively. X-ray and magnetic resonance imaging (MRI) revealed a healed fracture with osteolytic changes in the metaphyseal radius with periosteal reaction and abscess formation of the surrounding soft tissue structures. A two-staged procedure was performed with adequate debridement of the bone and dead space management with an antibiotic-loaded polymethyl methacrylate (PMMA) spacer at stage 1. After infection control, the spacer was removed and the defect was filled with autologous bone in one case and with a calcium sulphate-hydroxyapatite biomaterial in the other case. In each of the two patients, the infection was controlled and a stable consolidation of the distal radius in good alignment was achieved. In one case, the epiphyseal plate was impaired by the infection and premature closure of the epiphyseal plate was noted resulting in a post-infection ulna plus variant. In conclusion, a fracture-related infection after Kirschner wire fixation of pediatric distal radius fractures is a rare complication but can occur. A two-stage procedure with infection control and subsequent bone defect reconstruction was successful in the presented two cases. Premature closure of the epiphyseal growth plate of the distal radius is a potential complication.

Geometric parameterization of unit cell configurations for reduced basis approximation

To facilitate rapid yet accurate multiscale homogenization, we formulate geometric mapping schemes that effectively handles the fiber radius changes of a unit cell to dispense with mesh regeneration. To further expedite unit cell analysis involving fiber radius variation, we integrate the formulated geometric transformations into reduced basis analysis using an empirical interpolation method. For demonstration, we examine the proposed geometric parameterization strategies with the linear elastic analyses of square and hexagonal unit cells under tension and shear loads, respectively. Overall, reduced basis analyses combined with the devised geometric mappings are found more efficient than the corresponding finite element analyses while producing insignificant errors.

Monotonicity of the Cores of Massive Stars

Massive stars are linked to diverse astronomical processes and objects including star formation, supernovae and their remnants, cosmic rays, interstellar media, and galaxy evolution. Understanding their properties is of primary importance for modern astronomy, and finding simple rules that characterize them is especially useful. However, theoretical simulations have not yet realized such relations, instead finding that the late evolutionary phases are significantly affected by a complicated interplay between nuclear reactions, chemical mixing, and neutrino radiation, leading to nonmonotonic initial-mass dependencies of the iron core mass and the compactness parameter. We conduct a set of stellar evolution simulations, in which evolutions of He star models are followed until their central densities uniformly reach 1010 g cm−3, and analyze their final structures as well as their evolutionary properties, including the lifetime, surface radius change, and presumable fates after core collapse. Based on the homogeneous data set, we have found that monotonicity is inherent in the cores of massive stars. We show that not only the density, entropy, and chemical distributions, but also their lifetimes and explosion properties such as the proto-neutron-star mass and the explosion energy can be simultaneously ordered into a monotonic sequence. This monotonicity can be regarded as an empirical principle that characterizes the cores of massive stars.

Analyzing Wireless Mesh Network Using Spectral Graph Theory

Wireless mesh networks (WMNs) are a type of wireless network that can be used for various applications, such as Internet access, disaster response, and military communication. These networks consist of mesh routers that can communicate with each other and form a mesh topology, allowing them to provide connectivity even if some of the routers fail or are out of range. In this study, we used spectral graph theory to analyze the performance of a WMN. For the analysis process, software was developed to calculate the topological characteristics of the graph representing the WMN. The correlation between the values of the parameters of spectral graph theory and the topological characteristics of the observed network is analyzed. First, an analysis of the influence of the change in signal strength, in the observed WMN, on the algebraic connectivity was performed, and then the change in the spectral radius was also analyzed. The analysis was performed using special software, which was developed for that purpose.

Subnanometer-Resolution Nanoparticle Sensing through the Strong Coupling between Surface Plasmon Polariton Whispering Gallery Resonances and Localized Surface Plasmon

High-resolution nanoparticle sensing is very important, and many schemes have been proposed to achieve this goal. Circular nanocavities in which surface plasmon polariton (SPP) whispering gallery mode (WGM) resonances were excited were designed to sense particles of ultra-small size and with high resolution. Localized surface plasmon resonances (LSPRs) were excited when a metal particle was set in the circular cavity. The SPP WGM split into symmetric mode (SM) and antisymmetric mode (ASM) due to the LSPRs scattering into the SPPs. The strong coupling between SM resonance and LSPRs generated positive and opposite modes, which were sensitive to the variation in nanoparticle size and position. Even a small nanometer-sized metal particle introduced LSPRs and produced mode splitting. The WGM mode splitting induced by LSPRs reduced the sensing limit. The simulation results show that 1 nm changes in nanoparticle radius and position led to SM 11.8 nm and 10.2 nm wavelength shifts, respectively. This means that variations of 0.09 nm in size and 0.1 nm in position can be sensed with a 1 nm spectral resolution. The strong coupling between SPP WGM and LSPRs can be applied to sense at a subnanometer resolution.

Tilting refractive x-ray lenses for fine-tuning of their focal length.

In this work, we measure and model tilted x-ray refractive lenses to investigate their effects on an x-ray beam. The modelling is benchmarked against at-wavelength metrology obtained with x-ray speckle vector tracking experiments (XSVT) at the BM05 beamline at the ESRF-EBS light source, showing very good agreement. This validation permits us to explore possible applications of tilted x-ray lenses in optical design. We conclude that while tilting 2D lenses does not seem interesting from the point of view of aberration-free focusing, tilting 1D lenses around their focusing direction can be used for smoothly fine-tuning their focal length. We demonstrate experimentally this continuous change in the apparent lens radius of curvature R: a reduction up to a factor of two and beyond is achieved and possible applications in beamline optical design are proposed.

Design of few-mode erbium-doped fiber with a low differential modal gain and weak coupling based on layered doping.

A step index few-mode erbium-doped fiber (FM-EDF) for mode gain equalization is designed and proposed in this paper, which uses the layered-doping method to reduce the differential mode gain (DMG). The optimum structure of FM-EDF is obtained by adjusting the doping radius and doping concentration. When this structure is applied to a few-mode erbium-doped fiber amplifier (FM-EDFA), the DMG in the range of 1550-1565nm is ∼0.28d B, and the DMG of the whole C-band is usually less than 0.5dB. At the same time, the gain of each mode in 1530-1555nm is ∼20d B, while the gain decreases gradually in the 1555-1565nm due to the absorption characteristics of erbium ions. In addition, the minimum refractive index difference (Δ n eff) between modes is 1.29∗10-3 due to the selection of the refractive index and radius of the fiber core, which will greatly reduce the coupling between modes in practical application. Tolerances in the fiber manufacturing process are also considered for reliable FM-EDFA performance. When the doping concentration or the doping radius changes based on the precise value, the DMG will increase to a certain extent. In general, the DMG can maintain a small value, which is beneficial to applications in optical communication systems.

Typical electrical, mechanical, electromechanical characteristics of copper-encapsulated REBCO tapes after processing in temperature under 250 °C

Heat treatments are inevitable not only in the production of rare earth barium copper oxide (REBCO) tapes, but also in their post-processing for applications, typically, in soldering and epoxy/wax impregnation during the fabrication of REBCO coils. In general, the heat treatment of REBCO tapes should be carried out at lower temperature for a shorter time, but the specific safe boundary of heat-treatment temperature and time for REBCO tapes is still unknown. Therefore, a comprehensive study on the typical electrical, mechanical, and electromechanical characteristics of REBCO tapes after heat treatments under temperature of 250 °C is necessary. This work focus on the copper-encapsulated REBCO tapes, which are more robust (while with much lower engineering current density) to be processed in application systems than the tapes without encapsulation. The critical current degradation, stress–strain characteristic, and electromechanical properties of REBCO tapes were measured after heat treatments at different temperatures in argon and oxygen atmosphere. A 2D finite element (FE) analysis model was established for detailed stress/train analyzes under tension and bending based on the analysis of residual stress/strain. The results indicate that the critical current of the copper-encapsulated REBCO tapes decreases with increasing heat-treatment temperature and dwell time, and is of no evident relation to atmosphere. In addition, increased temperature of heat treatment leads to an obvious decrease in the yield strength and critical tensile stress. This effect is mainly attributed to the degradation of mechanical properties of the encapsulated copper layer, which is demonstrated by the combination of our FE simulation and the experiments results. Interestingly, the change in the critical bending radius due to heat treatments was slight, because the bending axial strain of the REBCO layer remained almost unchanged after heating. It is also worthy to note that all the properties tested in this study were irrelevant to the external oxygen partial pressure during the heating process. As a practical conclusion for the application systems, an upper and atmosphere-irrelevant limit of processing temperature of 130 °C or 150 °C (2 h dwell time) was proposed for copper-encapsulated REBCO tapes, under which the critical current, yield strength, critical tensile stress/strain and critical bending radius of the copper-encapsulated REBCO tapes decay by <1% or 3%, respectively.

Numerical Investigation on Potential Influencing Factors Affecting Drainage Effective Radius of Crossing Borehole

Crossing borehole is an effective means to eliminate the outburst risk of coal and gas. The influence of borehole inclination angle, borehole diameter, and drainage time on the effective radius of gas drainage are studied by numerical simulation and engineering example verification. The study shows that the effective radius changes in a “U” shape with the increase in borehole inclination angle. When the angle α of the borehole and coal seam plane decreases, the effective radius increases. Furthermore, the coal mass around the borehole is broken by shear deformation, which is consistent with the results of the inner peephole. The effective radiuses are different in coal seam dip X and strike Y. When α is small, the effective radius in the X direction is generally wider. When α is large (α ≤ 90°), the effective radiuses in the X and Y directions are close. The effective radius is positively correlated with the borehole diameter and is more significantly influenced by increasing borehole diameter when α is small. The effective radius increases as a negative exponential function with time and eventually converges to a constant. The study has practical implications for the design of crossing borehole in the coal seam floor.

The quasi-adiabatic relaxation of haloes in the IllustrisTNG and EAGLE cosmological simulations

AbstractThe dark matter content of a gravitationally bound halo is known to be affected by the galaxy and gas it hosts. We characterize this response for haloes spanning over four orders of magnitude in mass in the hydrodynamical simulation suites IllustrisTNG and EAGLE. We present simple fitting functions in the spherically averaged quasi-adiabatic relaxation framework that accurately capture the dark matter response over the full range of halo mass and halo-centric distance we explore. We show that commonly employed schemes, which consider the relative change in radius rf/ri − 1 of a spherical dark matter shell to be a function of only the relative change in its mass Mi/Mf − 1, do not accurately describe the measured response of most haloes in IllustrisTNG and EAGLE. Rather, rf/ri additionally explicitly depends upon halo-centric distance rf/Rvir for haloes with virial radius Rvir, being very similar between IllustrisTNG and EAGLE and across halo mass. We also account for a previously unmodelled effect, likely driven by feedback-related outflows, in which shells having rf/ri ≃ 1 (i.e. no relaxation) have Mi/Mf significantly different from unity. Our results are immediately applicable to a number of semi-analytical tools for modelling galactic and large-scale structure. We also study the dependence of this response on several halo and galaxy properties beyond total mass, finding that it is primarily related to halo concentration and star formation rate. We discuss possible extensions of these results to build a deeper physical understanding of the small-scale connection between dark matter and baryons.

Phenological assessment of transpiration: The stem-temp approach for determining start and end of season

Field-based assessment of transpiration phenology in boreal tree species is a significant challenge. Here we develop an objective approach that uses stem radius change and its correlation with sapwood temperature to determine the timing of phenological changes in transpiration in mixed evergreen species. We test the stem-temp approach using a five year stem-radius dataset from black spruce (Picea mariana) and jack pine (Pinus banksiana) trees in Saskatchewan (2016–2020). We further compare transpiration phenological transition dates from this approach with tower-based phenological assessment from green chromatic coordinate derived from phenocam images, eddy-covariance-derived evapotranspiration and carbon uptake, tower-based measurements of solar-induced chlorophyll fluorescence and snowmelt timing. The stem-temp approach identified the start and end of four key transpiration phenological phases: (i) the end of temperature-driven cycles indicating the start of biological activity, (ii) the onset of stem rehydration, (iii) the onset of transpiration, and (iv) the end of transpiration-driven cycles. The proposed method is thus useful for characterizing the timing of changes in transpiration phenology and provides information about distinct processes that cannot be assessed with canopy-level phenological measurements alone.

Photon orbits and phase transition for non-linear charged anti-de Sitter black holes

In this work, we investigate the relation between the photon sphere radius and the first-order phase transition for the charged Einstein-power-Yang-Mills AdS black hole. Through the analysis, we find with a certain condition there exist the non-monotonic behaviors between the photon sphere radius, the impact parameter, the non-linear Yang-Mills charge parameter, temperature, and pressure. And both the changes of photon sphere radius and impact parameter before and after phase transition can be regarded as the order parameter, their critical exponents near the critical point are equal to the same value 1/2, just like the ordinary thermal systems. These indicate that there maybe exists a universal relation of gravity nearby the critical point for a black hole thermodynamical system. Furthermore, the effect of impact parameter on the deflect angle is also investigated.

P21 A novel, fast, impedance-based antimicrobial susceptibility test for Neisseria gonorrhoeae

Abstract Objectives To demonstrate that the impedance-based fast antimicrobial susceptibility test (iFAST) can define N. gonorrhoeae susceptibility for a range of frontline antibiotics, and determine time taken to see responses. Background Gonorrhoea is the second most common bacterial sexually transmitted infection in the UK. It can cause complicated infection and infertility if not treated effectively. Resistance to frontline treatments and MDR N. gonorrhoeae infections (‘super gonorrhoea’) are increasing, fuelled by inappropriate selection of antibiotics. The current gold-standard antimicrobial susceptibility test (AST) for N. gonorrhoeae is MIC agar dilution, which is time-consuming (∼7 days) and labour-intensive. Unemo et al. 2020 (https://doi.org/10.1093/jac/dkw288) published detailed resistance profiles of WHO-reference N. gonorrhoeae strains. This project aimed to test whether these strain sensitivities against front line antibiotics ceftriaxone, ciprofloxacin and azithromycin could be defined faster using iFAST, which calculates the opacity and electrical size of individual cells by measuring change in electrical currents as single cells flow between micro-electrodes. Antibiotic-treated susceptible bacteria change electrical radius (surrogate measure of cell size) and opacity (based on properties of bacterial membranes as resistors), compared with untreated or resistant cells (Spencer et al. 2020, 10.1038/s41467-020-18902-x). Methods N. gonorrhoeae WHO-reference strains F and X were incubated overnight on standard chocolate agar plates at 37°C, 3%–5% CO2. 10 viable plate colonies were selected and inoculated in 37°C brain heart infusion media, supplemented with 0.42% sodium bicarbonate and 1% Isovitalex. After 30 min incubation at 37°C with shaking, the cell concentration was measured on iFAST and added to five concentrations of ceftriaxone, ciprofloxacin, and azithromycin (at the published agar MIC and ±2 × 2-fold concentration) or at EUCAST susceptibility breakpoint concentrations (strains F, X, O, V, K, Y), at a final cell concentration of 5 × 105 cells/mL. Cells were exposed at 37°C 250 rpm for 2, 3 and 4 h. 60 µL of 1:10 dilutions of sample were read on iFAST. MATLAB analysis software created contours around 50% of untreated cells and overlayed this on exposed population scattergrams. Results Electrical MICs (eMICs) showed differences in cell count, electrical radius and opacity between cells exposed to concentrations ≥MIC, subinhibitory concentrations, or untreated cells for all three frontline drugs. These differences were detectable after 2 h of antibiotic exposure but were clearest after 4 h. When tested at breakpoint concentrations only, iFAST accurately detected susceptibility of tested N. gonorrhoeae reference strains after 4 h exposure. Generally, susceptible cells had reduced electrical cell size and increased opacity distribution (out of contour shift) for all compounds, though there was variation due to differing modes of action. Ciprofloxacin and azithromycin had more decreased electrical cell radius with increased opacity spread. Comparatively, ceftriaxone had smaller changes in electrical radius and a larger spread of opacity readings. Conclusions iFAST is potentially a rapid and accurate method for determining N. gonorrhoeae strain susceptibility for ceftriaxone, ciprofloxacin, and azithromycin. With additional validation, it may be useful for future N. gonorrhoeae AST development, as well as investigating the effect of novel antimicrobial compounds.

Climatic control of high-resolution stem radius changes in a drought-limited southern boreal forest

Key messageStem radius changes measured at high temporal resolution in a drought-limited southern boreal forest were primarily related to soil temperature and partly soil moisture variation, but only weakly to VPD.Forest productivity at the southern fringe of the boreal forest biome in Inner Asia is strongly drought-limited, as is evident from dendrochronological analyses. Using electronic point dendrometers, we studied the climate response of stem radius changes at high temporal resolution (10-min intervals) in a mixed larch–birch forest in northern Mongolia in a drought year and two subsequent moist years. Larch trees showed stronger stem radius fluctuations than birches, and this difference was more pronounced in dry than in moist years. Stem radius changes were most tightly related to soil temperature variation, while soil moisture was the dominant controlling factor only in birch in the dry year. Correlations with the atmospheric vapor pressure deficit (VPD), and even more so with air temperature, were much weaker. While the linkage between radius change and VPD might primarily reflect diurnal transpiration-driven stem shrinkage and expansion, soil temperature is thought to directly affect cambial cell division and elongation during wood formation. We conclude that the phenology of stemwood increment is strongly controlled by soil temperature even in drought-limited southern boreal forests under continental climate due to the combination of cold and dry climate.

Dynamics of intermetallics formation in the Al/Ni reactive wetting system

Due to the complexity of interfacial reactions during reactive wetting process at high temperatures, the intrinsic mechanism behind the formation and growth of intermetallic compounds (IMCs) is still unclear. This study presents insight into the possible formation of Al/Ni IMCs in the Al (l)/Ni (s) wetting system at 1023.15 K using molecular dynamics (MD) simulation. The reactive wetting process has been broadly classified into three regimes based on the Al/Ni interphase condition: fast spreading (mostly non-reactive), crossover (dissolutive), and slow-spreading (reactive). It is found that the intermetallic phases are nucleated during the dissolutive phase; however, the stable IMCs are formed during the reactive stage and are mostly composed of AlNi and Al3Ni5. The growth of IMCs in the radial direction shows the same behavior as the contact radius of the droplet, which is a significant increase of both the droplet radius and IMCs growth in the radial direction before the droplet reaches its quasi-equilibrium base radius. Quasi-equilibrium droplet radius occurs when changes in droplet radius are negligible. In a quasi-equilibrium regime, no significant change in droplet radius and IMCs growth is observed. In contrast, the IMCs growth in the normal direction shows the opposite behavior: the thickness of IMCs increases significantly during the quasi-equilibrium regime.

MAXI J1820+070 X-ray spectral-timing reveals the nature of the accretion flow in black hole binaries

ABSTRACT Black hole X-ray binaries display significant stochastic variability on short time-scales (0.01–100 s), with a complex pattern of lags in correlated variability seen in different energy bands. This behaviour is generally interpreted in a model where slow fluctuations stirred up at large radii propagate down through the accretion flow, modulating faster fluctuations generated at smaller radii. Coupling this scenario with radially stratified emission opens the way to measure the propagation time-scale from data, allowing direct tests of the accretion flow structure. We previously developed a model based on this picture and showed that it could fit the Neutron star Interior Composition Explorer (NICER; 0.5–10 keV) data from the brightest recent black hole transient, MAXI J1820+070. However, here we show it fails when extrapolated to higher energy variability data from the Insight-Hard X-ray Modulation Telescope(HXMT). We extend our model so that the spectrum emitted at each radius changes shape in response to fluctuations (pivoting) rather than just changing normalization. This gives the strong suppression of fractional variability as a function of energy seen in the data. The derived propagation time-scale is slower than predicted by a magnetically arrested disc (MAD), despite this system showing a strong jet. Our new model jointly fits the spectrum and variability up to 50 keV, though still cannot match all the data above this. Nonetheless, the good fit from 3 to 40 keV means the quasi-periodic oscillation (QPO) can most easily be explained as an extrinsic modulation of the flow, such as produced in the Lense–Thirring precession, rather than arising in an additional spectral-timing component such as the jet.

Weak Deflection Angle, Hawking Radiation and Greybody Bound of Reissner–Nordström Black Hole Corrected by Bounce Parameter

In this study, we probe the weak lensing by a Reissner–Nordström black hole corrected by bounce parameter in plasma and dark matter mediums. For this, the optical geometry and the Gibbons–Werner approach are utilized to obtain the bending angle in the weak field limitations. We examine that the impact of these mediums increases the black hole’s bending angle. In addition, we graphically study the deflection angle of light with respect to the impact parameter and examine that the bounce parameter directly affects the angle. Further, we compute the Hawking radiation via a topological method involving two invariants and verify our obtained result with the standard method of calculating the Hawking temperature. In addition, we compute the greybody factor’s bound of the black hole. Moreover, we analyze the bound graphically and observe that the bound shows convergent behavior. We also study that our attained results reduce the results of the Reissner–Nordström and Schwarzschild black holes by reducing the parameters. Finally, we probe how the bounce parameter affected the shadow radius and compared it to the shadow produced if the black hole is immersed in plasma. It is revealed that the rate at which the shadow radius changes with respect to r easily tends to zero under the effect of the bounce parameter, while the plasma merely increases the shadow radius.

Analytical solution for expandable polyurethane grouting in a rock fracture

Expandable polyurethane grout has been extensively utilized for the reinforcement and sealing of rock fractures. The diffusion mechanism of this grout is particularly unique, owing to the time-dependent characteristics of both its density and viscosity. However, the non-synchronous relationship between the change in diffusion radius and pressure poses challenges in deriving analytical solutions. In light of this, our study presents an innovative analytical model to effectively simulate the diffusion behavior of expandable polyurethane within rock fractures. Notably, this model considers both the self-expanding source and the convective driving force. The outcomes of our research demonstrate that spread and pressure exhibit distinct characteristic times, allowing us to employ the same equations with diverse parameters, yielding a semi-deterministic approach. In this approach, the first run of the model is deterministic while the second entails empirical considerations. Further, a comparison of analytical results with experimental injections was made involving varying grouting quantities, revealing excellent agreement between the measured and calculated pressures. The present model can be employed for fitting and real-time monitoring after calibration, enabling the exploration of conventional stop criteria, as well as refusal and mass criteria. Additionally, this model facilitates the formulation of conditions to effectively achieve the target, considering vital factors such as the time-spread relation, expansion ratio, and gel time.

FIXED SPEED MECHANISM

It has been established that from the key circumstance that determines the possibility of generalizing cyclotron motion to mechanics, which consists in the fact that the Lagrangian of an electron is twice its kinetic energy, which, as applied to a mechanical device rotator, should be interpreted as the equality of kinetic and potential energies, it necessarily follows that the composition of a stabilized The rotator must include elements that are able to store both of these types of energy, namely, a load and a spring. The natural frequency of rotation of a stabilized rotator is strictly fixed (it does not depend on either the moment of inertia or the moment of momentum) and remarkably coincides with the natural frequency of oscillations of a pendulum with identical parameters. When the angular momentum changes, the radius and tangential velocity change (the rotation frequency does not change and is equal to its own).

Acoustic radiation force of elastic spherical shell with eccentric droplet in plane wave acoustic field

Based on the application of acoustic waves in cell manipulation, a model consisting of an elastic spherical shell and eccentric droplet is established to simulate a eukaryotic cell and analyze the acoustic radiation force (ARF) on the cell. In this work, we derive an exact expression for the ARF on the liquid-filled spherical shell. The influence of eccentric distance, radius of the eccentric droplet and impedance of the medium inside the liquid-filled spherical shell on the ARF are analyzed numerically. The results show that the ARF is very sensitive to the position and size of the eccentric droplet. As the eccentricity of the eccentric droplet increases, the ARF becomes greater. In a low frequency region (&lt;i&gt;ka&lt;/i&gt;&lt;3) the resonance peak point increases, and the position of the curve ventral point shifts to the high frequency region (&lt;i&gt;ka&lt;/i&gt;&gt;3) with the increase of the radius of the eccentric droplet. The effect of the position variation on the ARF is more significant than that of the radius change, and both of their effects will be superimposed on each other. The ARF, as a function of &lt;i&gt;ka,&lt;/i&gt; is mainly affected by the variation of the nucleus characteristic impedance. The ARF amplitude around &lt;i&gt;ka&lt;/i&gt; = 5 increases and the position of the ventral point tends to shift rightwards with the enlargement of the nucleus impedance. Therefore, the radiation response at a certain frequency or in a cell size range can be enhanced when the nucleus impedance increases. The results of this study provide theoretical basis for the cell sorting and targeted therapy.