Fine Structure Research Articles

Local Regularity in Chaotic Bursting Oscillations Induced by Stable Attractors in Fast Subsystem

Chaos is thought to be random, but a few constants, such as Lyapunov exponent and fractal dimension, can be obtained by statistic measures based on a large amount of data. This paper presents the local regularity in chaotic bursting oscillations caused by the coupling of two scales in frequency domain. When slow-varying external excitation is introduced in a well-known Nosé–Hoover oscillator, called also Sprott-A system, different types of bursting attractors, such as periodic and chaotic bursting oscillations, can be observed. By regarding the external excitation as a slow-varying parameter, the dynamical evolution of the generalized autonomous fast subsystem is obtained. Two typical cases for the physical parameters are considered, in which codimension-1 fold and codimension-2 fold–Hopf bifurcations take place, respectively. Several types of coexistent attractors in the fast subsystem, such as the coexistence of equilibrium points, the coexistence of equilibrium point and sequence of period-doubling bifurcation routine to chaos, may appear, which may lead to different bursting oscillations, the mechanism of which is presented by overlapping the transformed phase portrait and the behaviors of the fast subsystem. The trajectory of periodic bursting oscillations visits the equilibrium points in turn via fold bifurcations, while fold–Hopf bifurcation may result in quasi-periodic bursting oscillations. Two coexisted asymmetric bursting attractors may expand in the phase space with the increase of exciting amplitude. The interaction forms an enlarged symmetric bursting attractor. The influence of the periodic windows on the full vector field may appear, which causes the spiking stage to be divided into segments with different behaviors. Specially spiking state can oscillate according to different regular cycles as well as chaos in turn, which suggests that regular attractors are embedded in chaos. More periodic windows exist in the fast subsystem, more fine structures can be observed in the spiking stage. Accordingly, the coexisted attractors, together with the related bifurcations, in the fast subsystem, may be one of the main reasons for the complexity of the world with the coupling of multiple scales.

Upper Eyelid Blepharoptosis Correction Performed Under the Operating Microscope.

Eyelid blepharoptosis correction is commonly performed with loupe magnification. The posture in which this operation is performed, with cervical spine flexion and forward lean, places significant stress on the cervical spine. Performing upper eyelid surgery under the operating microscope is not commonly practiced. The benefits are significantly better surgeon's posture while operating and potential improved surgical outcomes. These ergonomic and outcome measures were examined in this prospective study. From the June 2023 to June 2024, 86 cases of bilateral ptosis correction were performed (172 eyelids) with the microscope. The mean duration of surgery was 115 minutes for bilateral ptosis correction. Our revision rate was 3%. We found the following surgical advantages with this approach: (1) Superior visual clarity with a higher and adjustable magnification and (2) consistent confocal illumination of the operative field, (3) improved precision of dissection, (4) hemostasis and (5) clear distinction of fine anatomical structures crucial to reconstructive success. The postoperative recovery was faster with better functional and cosmetic outcomes as bruising and edema was minimized from less induction of surgical trauma. Importantly as well, for the surgeon, the operating microscope may extend the longevity of one's surgical career. The postural ergonomics and cervical unloading afforded by the operating microscope can mitigate cervical spine stress and injury CONCLUSIONS: We found 2 compelling benefits with this approach. Firstly, the surgical outcomes were superior. Secondly, the surgeon's posture is upright while operating. This long-term benefits of this could not be overstated in preventing cervical spineinjuries. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Constraints on the Fractional Changes of the Fundamental Constants at a Look-back Time of 2.5 Myr

Abstract The quantum nature of gravity remains one of the greatest mysteries of modern physics, with many unified theories predicting variations in fundamental constants across space and time. Here we present precise measurements of these variations at galactic dynamical timescales—a critical but previously unexplored regime. Using simultaneous observations of H i and OH lines in M31, we probe potential variations of fundamental constants at a look-back time of 2.5 million yr. We obtained Δ ( μ α 2 g p 0.64 ) / ( μ α 2 g p 0.64 ) < 3.6 × 1 0 − 6 , with complementary constraints on Δ(μα 2)/(μα 2) < 4.6 × 10−3, and Δg p /g p < 7.2 × 10−3, where α is the fine structure constant, μ is the proton–electron mass ratio, and g p is the proton g-factor. These results bridge the gap between laboratory tests and cosmological observations, providing unique insights into the coupling between local dynamics and fundamental physics. Our findings challenge theories predicting significant variations over galactic timescales while demonstrating a powerful new probe of quantum gravity models.

Temporal Fine Structure and Working Memory Abilities on Deciding the Probable Compression Speed in Hearing Aids

Background and Aim: Temporal Fine Structure (TFS) sensitivity and Working Memory (WM) abilities have been widely studied individually as the contributing factors for deciding compression speed in hearing aids. The study aimed to develop a clinical framework for setting optimal compression speed using combination of TFS sensitivity and WM abilities. Methods: Participants were 25 native Kannada-speaking adults (mean age 70 years). We evaluated the participant’s TFS sensitivity using the TFS -Adaptive Frequency (AF) and WM abilities using reading span test. Further, aided sentence recognition in noise was tested to obtain find the signal-to-noise ratio 50% (SNR 50) correct identification happens in Fast Acting Compression (FAC) and Slow Acting Compression (SAC) modes. Results: Individuals with good TFS sensitivity demonstrated significantly lower SNR 50 scores with FAC and individuals with poor WM showed significantly lower SNR 50 with SAC. However, individuals with poor TFS sensitivity and individuals with good WM ability showed no significance on SNR 50 obtained between FAC and SAC. A strong negative correlation existed between TFS sensitivity and SNR 50 in both SAC and FAC modes even after accounting for WM abilities. There was a mild negative correlation between WM abilities and SNR 50 in FAC mode only, but this was not significant after accounting for TFS sensitivity. Conclusion: Using the results of the present study along with the literature findings, a clinical framework was devised to enable the selection of appropriate compression speed for optimal speech understanding with hearing aids.Keywords: Release time; amplification; speech in noise; elderly; hearing-impaired

Boosting Oxygen Reduction Reaction Performance of Fe Single‐Atom Catalysts Via Precise Control of the Coordination Environment

AbstractFe single‐atom on N‐doped carbon (FeN‐C) catalysts emerge as promising alternatives to commercial Pt/C for the oxygen reduction reaction. Heterogeneous atom doping is proposed to be effective for modulating catalyst performance. Despite this, the relationship between the fine coordination structure of the doped atoms and catalytic activity of the central metal site remains poorly understood. Herein, Fe single‐atom catalysts with S doped in either the first coordination shell (FeSN–C) or the second coordination shell (FeN–SC) of the Fe active site are synthesized to compare the effects of different coordination structure. FeN–SC exhibits prominent performance with a half‐wave potential of 0.92 V in rotating disk electrode and a peak power density of 251 mW cm−2 in the zinc–air battery. Theoretical studies reveal that S doping effectively modulates the electronic structure and charge transfer at the Fe center. Compared to S atoms directly coordinated within the first coordination shell, S located in the second coordination shell is more effective in optimizing the adsorption and desorption energy barriers of oxygen‐containing intermediates at the active sites. This study provides a new strategy to adjust the catalytic performance by engineering the multilayer coordination structure at the active center of the single‐atom catalyst.

Theories of the Effects of Copolymer Addition on the Interfacial Tension between Polymer Blend Components: A Review

AbstractThis review discusses methods for calculating the equilibrium interfacial tension in strongly immiscible polymer blends compatibilized with copolymers. The discussion is focused on typical polymer blends with fine phase structures; in these polymer blends, the volume of the interfacial layer is generally not negligible with respect to the volume of the bulk phases. The main models and calculation procedures that are predominantly used are compared, and their practicalities are discussed. Neither the expressions derived using the dry brush approximation nor those derived using the wet brush approximation are applicable to blends compatibilized with copolymers that have block lengths comparable to those of the compatibilized homopolymers. The amount of a copolymer in the interfacial layer of a polymer blend is generally not negligible with respect to its amount in the bulk phases. Therefore, approximations that are successfully used for the calculation of the interfacial tension measured by common methods cannot be applied to calculation of the interfacial tension in the polymer blends.

Hybrid attention structure preserving network for reconstruction of under-sampled OCT images

Optical coherence tomography (OCT) is a non-invasive, high-resolution imaging technology that provides cross-sectional images of tissues. Dense acquisition of A-scans along the fast axis is required to obtain high digital resolution images. However, the dense acquisition will increase the acquisition time, causing the discomfort of patients. In addition, the longer acquisition time may lead to motion artifacts, thereby reducing imaging quality. In this work, we proposed a hybrid attention structure preserving network (HASPN) to achieve super-resolution of under-sampled OCT images to speed up the acquisition. It utilized adaptive dilated convolution-based channel attention (ADCCA) and enhanced spatial attention (ESA) to better capture the channel and spatial information of the feature. Moreover, convolutional neural networks (CNNs) exhibit a higher sensitivity of low-frequency than high-frequency information, which may lead to a limited performance on reconstructing fine structures. To address this problem, we introduced an additional branch, i.e., textures & details branch, using high-frequency decomposition images to better super-resolve retinal structures. The superiority of our method was demonstrated by qualitative and quantitative comparisons with mainstream methods. Furthermore, HASPN was applied to three out-of-distribution datasets, validating its strong generalization capability.

Improved precision and accuracy of electron energy-loss spectroscopy quantification via fine structure fitting with constrained optimization.

Improved precision and accuracy of electron energy-loss spectroscopy quantification via fine structure fitting with constrained optimization.

The molecular structure of leaf starch from three cereal crops

The molecular structure of leaf starch from three cereal crops

Efficient preparation process and fine structural analysis of polysaccharides from Black soybean (Glycine max (L.) Merr.) hull

Efficient preparation process and fine structural analysis of polysaccharides from Black soybean (Glycine max (L.) Merr.) hull

High Spatial-Resolution and Acquisition-Efficiency Cardiac MR T1 Mapping Based on Radial bSSFP and a Low-Rank Tensor Constraint.

Cardiac T1 mapping is valuable for evaluating myocardial fibrosis, yet its resolution and acquisition efficiency are limited, potentially obscuring visualization of small pathologies. To develop a technique for high-resolution cardiac T1 mapping with a less-than-100-millisecond acquisition window based on radial MOdified Look-Locker Inversion recovery (MOLLI) and a calibrationless space-contrast-coil locally low-rank tensor (SCC-LLRT) constrained reconstruction. Prospective. Sixteen healthy subjects (age 25 ± 3 years, 44% females) and 12 patients with suspected cardiomyopathy (age 57 ± 15 years, 42% females), NiCl2-agar phantom. 3-T, standard MOLLI, radial MOLLI, inversion-recovery spin-echo, late gadolinium enhancement. SCC-LLRT was compared to a conventional locally low-rank (LLR) method through simulations using Normalized Root-Mean-Square Error (NRMSE) and Structural Similarity Index Measure (SSIM). Radial MOLLI was compared to standard MOLLI across phantom, healthy subjects, and patients. Three independent readers subjectively evaluated the quality of T1 maps using a 5-point scale (5 = best). Paired t-test, Wilcoxon signed-rank test, intraclass correlation coefficient analysis, linear regression, Bland-Altman analysis. P < 0.05 was considered statistically significant. In simulations, SCC-LLRT demonstrated a significant improvement in NRMSE and SSIM compared to LLR. In phantom, both radial MOLLI and standard MOLLI provided consistent T1 estimates across different heart rates. In healthy subjects, radial MOLLI exhibited a significantly lower mean T1 (1115 ± 39 msec vs. 1155 ± 36 msec), similar T1 SD (74 ± 14 msec vs. 67 ± 23 msec, P = 0.20), and similar T1 reproducibility (28 ± 18 msec vs. 22 ± 15 msec, P = 0.34) compared to standard MOLLI. In patients, the proposed method significantly improved the sharpness of myocardial boundaries (4.50 ± 0.65 vs. 3.25 ± 0.43), the conspicuity of papillary muscles and fine structures (4.33 ± 0.74 vs. 3.33 ± 0.47), and artifacts (4.75 ± 0.43 vs. 3.83 ± 0.55). The reconstruction time for a single slice was 5.2 hours. The proposed method enables high-resolution cardiac T1 mapping with a short acquisition window and improved image quality. 1 TECHNICAL EFFICACY: Stage 1.

Preparation, characterization and in vitro antioxidant activities of a homogeneous polysaccharide from Prunella vulgaris.

Preparation, characterization and in vitro antioxidant activities of a homogeneous polysaccharide from Prunella vulgaris.

Structural analysis and immunological activity of a novel low molecular weight neutral polysaccharide isolated from Hemerocallis citrina Borani.

Structural analysis and immunological activity of a novel low molecular weight neutral polysaccharide isolated from Hemerocallis citrina Borani.

Investigating the fine structures of ginkgo starch during kernel development and their correlations with thermal properties

Investigating the fine structures of ginkgo starch during kernel development and their correlations with thermal properties

Displays of high-grade Hyperchaos and bi-stability in an erbium-doped fiber three-ring mutual-coupled laser

Displays of high-grade Hyperchaos and bi-stability in an erbium-doped fiber three-ring mutual-coupled laser

Oligosaccharide-assisted resolution of holothurian fucosylated chondroitin sulfate for fine structure and P-selectin inhibition.

Oligosaccharide-assisted resolution of holothurian fucosylated chondroitin sulfate for fine structure and P-selectin inhibition.

Erythrocytes from gilthead seabream (Sparus aurata) and European sea bass (Dicentrarchus labrax) did not engage in phagocytosis.

Erythrocytes from gilthead seabream (Sparus aurata) and European sea bass (Dicentrarchus labrax) did not engage in phagocytosis.

Orange Room-Temperature Phosphorescence in Complexes of Pyrene-d10–β-Cyclodextrin with Bulk Molecules in the Presence of Oxygen

The long-lived room temperature phosphorescence (RTP) and fluorescence of a pyrene-d10–β-cyclodextrin (Pd10–CD) complex were studied before and after the removal of O2 as well as after the addition of bulk molecules (BM), namely, tert-butylbenzene, p-tert-butyltoluene, and adamantane. The biexponential decay of the RTP intensity of the complexes indicates the presence of two types of phosphorescent sites (PSs) in the crystal lattice of 2BM-2CD. The emission and quenching rate constants of Pd10 RTP in all the complexes and the PS structures were calculated by quantum chemistry methods. The assignments and selection rules of vibrational fine structure lines in the emission spectra are discussed.

A Voxel Method for Correcting the Self-absorption Effect in Fluorescence X-ray Absorption Fine Structure Spectra

A Voxel Method for Correcting the Self-absorption Effect in Fluorescence X-ray Absorption Fine Structure Spectra

Probing the fine structures of low atomic number catalysts by using electron energy loss spectroscopy

Probing the fine structures of low atomic number catalysts by using electron energy loss spectroscopy