Controlling the Formation of Polyhedral Block Copolymer Nanoparticles: Insights from Process Variables and Dynamic Modeling.

This study delves into the formation of nanoscale polyhedral block copolymer particles (PBCPs) exhibiting cubic, octahedral, and variant geometries. These structures represent a pioneering class that has never been fabricated previously. PBCP features distinct variations in curvature on the outer surface, aligning with the edges and corners of polyhedral shapes. This characteristic sharply contrasts with previous block copolymers (BCPs), which displayed a smooth spherical surface. The emergence of these cornered morphologies presents an intriguing and counterintuitive phenomenon and is linked to process parameters, such as evaporation rates and initial concentration, while keeping other variables constant. Using a system of coupled Cahn-Hillard (CCH) equations, we uncover the mechanisms driving polyhedral particle formation, emphasizing the importance of controlling relaxation parameters for shape variable u and microphase separation v. This unconventional approach, differing from traditional steepest descent method, allows for precise control and diverse polyhedral particle generation. Accelerating the shape variable u proves crucial for expediting precipitation and aligns with experimental observations. Employing the above theoretical model, we achieve shape predictions for particles and the microphase separation within them, which overcomes the limitations of ab initio computations. Additionally, a numerical stability analysis discerns the transient nature versus local minimizer characteristics. Overall, our findings contribute to understanding the complex interplay between process variables and the morphology of polyhedral BCP nanoparticles.

Reconstruction of hook grip function of the fingers in patients with traumatic brachial plexus injury.

We described a reconstruction method for restoring hook grip function of the fingers in patients with total brachial plexus injury. The paralysed latissimus dorsi muscle was transferred to the upper limb as a pedicle flap and sutured to the flexor digitorum profundus tendons. The muscle was then reanimated with two intercostal donor nerves to the thoraco-dorsal nerve. Fourteen young adult patients (mean 23 years, range 17 to 32 years) with traumatic brachial plexus injury who underwent reconstruction using this technique from 2000 to 2019. After mean follow-up of 65 months (range 20 to 170), finger flexion of strength greater than or equal to M3 was achieved in 10 of the 14 patients. The mean weight that could be lifted using a hook grip was 2.6 kg, and that which could be lifted with both hands was 4.1 kg. The intercostal nerve-innervated latissimus dorsi muscle transfer can provide useful hook grip hand function without the need to sacrifice donor vessels or healthy muscles.Level of evidence: IV.

Japanese Orthopaedic Association (JOA) clinical practice guidelines on the management of lateral epicondylitis of the humerus - Secondary publication.

BACKGROUND: The guidelines presented herein provide recommendations for the management of patients with lateral epicondylitis of the humerus. These recommendations are endorsed by the Japanese Orthopaedic Association (JOA) and Japan Elbow Society. METHODS: The JOA lateral epicondylitis guideline committee revised the previous guidelines on the basis of the "Medical Information Network Distribution Service Handbook for Clinical Practice Guideline Development 2014", which emphasized the importance of the balance between benefit and harm, and proposed a desirable method for preparing clinical guidelines in Japan. These guidelines consist of 11 clinical questions (CQs), 9 background questions (BQs), and 3 future research questions (FRQs). For each CQ, outcomes from the literature were collected and evaluated systematically according to the adopted study design. RESULTS: The committee proposed recommendations for each CQ by determining the level of evidence and assessing the consensus rate. Physical therapy was the best recommendation with the best evidence. The BQs and FRQs were answered by collecting evidence based on the literature. CONCLUSIONS: The guidelines presented herein were reviewed systematically, and recommendations were proposed for each CQ. These guidelines are expected to be widely used not only by surgeons or physicians but also by other healthcare providers, such as nurses, therapists, and athletic trainers.

Preoperative Evaluation and Surgical Simulation for Osteochondritis Dissecans of the Elbow Using Three-Dimensional MRI-CT Image Fusion Images.

We used our novel three-dimensional magnetic resonance imaging-computed tomography fusion images (3D MRI-CT fusion images; MCFIs) for detailed preoperative lesion evaluation and surgical simulation in osteochondritis dissecans (OCD) of the elbow. Herein, we introduce our procedure and report the findings of the assessment of its utility. We enrolled 16 men (mean age: 14.0 years) and performed preoperative MRI using 7 kg axial traction with a 3-Tesla imager and CT. Three-dimensional-MRI models of the humerus and articular cartilage and a 3D-CT model of the humerus were constructed. We created MCFIs using both models. We validated the findings obtained from the MCFIs and intraoperative findings using the following items: articular cartilage fissures and defects, articular surface deformities, vertical and horizontal lesion diameters, the International Cartilage Repair Society (ICRS) classification, and surgical procedures. The MCFIs accurately reproduced the lesions and correctly matched the ICRS classification in 93.5% of cases. Surgery was performed as simulated in all cases. Preoperatively measured lesion diameters exhibited no significant differences compared to the intraoperative measurements. MCFIs were useful in the evaluation of OCD lesions and detailed preoperative surgical simulation through accurate reproduction of 3D structural details of the lesions.

Solution landscapes of the diblock copolymer-homopolymer model under two-dimensional confinement.

We investigate the solution landscapes of the confined diblock copolymer and homopolymer in two-dimensional domain by using the extended Ohta-Kawasaki model. The projection saddle dynamics method is developed to compute the saddle points with mass conservation and construct the solution landscape by coupling with downward and upward search algorithms. A variety of stationary solutions are identified and classified in the solution landscape, including Flower class, Mosaic class, Core-shell class, and Tai-chi class. The relationships between different stable states are shown by either transition pathways connected by index-1 saddle points or dynamical pathways connected by a high-index saddle point. The solution landscapes also demonstrate the symmetry-breaking phenomena, in which more solutions with high symmetry are found when the domain size increases.

A novel three-dimensional MRI-CT image fusion technique for precise preoperative evaluation and treatment of capitellar osteochondritis dissecans.

OBJECTIVES: We developed a novel method to create three-dimensional magnetic resonance imaging-CT (3D MRI-CT) fusion images for detailed lesion evaluation and surgical simulation in capitellar osteochondritis dissecans (COCD). This study aimed to clarify its usefulness. METHODS: We enrolled 12 boys with COCD (mean age, 13.8 years) and preoperatively constructed 3D models of the humerus and articular cartilage from MR images obtained with a 3-T imager. For better visualization of the articular cartilage outline, we applied 7 kg of axial traction to the elbow during MRI. We also constructed a 3D model of the humerus from CT images. 3D MRI-CT fusion images were created using both models. The average distance difference between two corresponding points as per the 3D CT and 3D MRI models of the humerus was evaluated. Using the 3D MRI-CT fusion images, we measured longitudinal and transverse lesion diameters; evaluated articular cartilage fissures and defects, articular surface deformities, and the International Cartilage Repair Society (ICRS) classification; and validated the results using intraoperative findings. RESULTS: The mean average distance difference was 0.75 mm. The 3D MRI-CT fusion images accurately reproduced lesion conditions in every case and correctly predicted the ICRS classification with 100% accuracy. Preoperatively measured longitudinal and transverse lesion diameters were not significantly different from intraoperative measurements (p = 0.79, 0.32 respectively). CONCLUSION: 3D MRI-CT fusion images provide a detailed evaluation of COCD lesion severity by presenting the exact positional relationship between the articular cartilage and subchondral bone. KEY POINTS: • We developed a novel method to create three-dimensional magnetic resonance imaging-computed tomography (3D MRI-CT) fusion images for the evaluation of capitellar osteochondritis dissecans. • 3D MRI-CT fusion images enabled the accurate prediction of lesions and provided a detailed evaluation of lesion severity by presenting the exact positional relationship between the articular cartilage and subchondral bone.

Mathematical mechanism of state-dependent phase resetting properties of alpha rhythm in the human brain.

It is well-known that 10-Hz alpha oscillations in humans observed by electroencephalogram (EEG) are enhanced when the eyes are closed. Toward explaining this, a previous experimental study using manipulation by transcranial magnetic stimulation (TMS) revealed more global propagation of phase resetting in the eyes-open condition than in the eyes-closed condition in the alpha band. Those results indicate a significant increase of directed information flow across brain networks from the stimulated area to the rest of the brain when the eyes are open, suggesting that sensitivity to environmental changes and external stimuli is adaptively controlled by changing the dynamics of the alpha rhythm. However, the mathematical mechanism mediating the changes in the sensitivity has not been well elucidated. In this study, we propose a qualitative mathematical model that describes the characteristic behavior of the EEG phase dynamics. Numerically, we find that the propagation properties of the phase resetting qualitatively depend on whether the population of oscillators at the stimulated area are synchronized. These results support the hypothesis that the dynamics of the alpha oscillations controls sensitivity to external stimuli.

Ashura Particles: Experimental and Theoretical Approaches for Creating Phase-Separated Structures of Ternary Blended Polymers in Three-Dimensionally Confined Spaces.

Unique morphologies were found in binary and ternary polymer blended particles, including Ashura-type phase separation, which has three different polymer components on the particle surface. The morphologies of phase-separated structures in the binary polymer blended particles are discussed in terms of the surface tensions of the blended polymers. Structural control of ternary polymer blended particles was achieved based on the combination of polymers by examining binary polymer blended particles. A theoretical approach based on the Cahn-Hilliard equations gives identical morphologies with the experimental results. This work opens the way to creating polymer particles with sophisticated nanostructures by controlling their morphologies as predicted by theoretical simulations.

Neural network model for path-finding problems with the self-recovery property.

The large-scale synchronization of neural oscillations is crucial in the functional integration of brain modules, but the combination of modules changes depending on the task. A mathematical description of this flexibility is a key to elucidating the mechanism of such spontaneous neural activity. We present a model that finds the loop structure of a network whose nodes are connected by unidirectional links. Using this model, we propose a path-finding system that spontaneously finds a path connecting two specified nodes. The solution path is represented by phase-synchronized oscillatory solutions. The model has the self-recovery property: that is, it is a system with the ability to find a new path when one of the connections in the existing path is suddenly removed. We show that the model construction procedure is applicable to a wide class of nonlinear systems arising in chemical reactions and neural networks.

For how long do denervated muscles in children retain the ability to regenerate?: Restoration of elbow flexion and shoulder function by partial nerve transfer in a child with long-standing poliomyelitis-like paralysis.

BACKGROUND: In infant poliomyelitis or poliomyelitis-like paresis, there has been no means of treating residual paralysis and the policy has been to wait until an affected infant has grown sufficiently to enable tendon transfer or arthrodesis. However, recent reports have described relatively good results for early surgical intervention in the form of nerve transfer. METHODS: In a 4-year and 6-month-old child we transferred a partial ulnar nerve for elbow flexor reconstruction even 3 years and 10 months after the onset of poliomyelitis-like palsy and also transferred partial accessory and radial nerves for shoulder function restoration 6 months after the first operation. RESULTS: Elbow flexor restored M4 on the British Medical Research Council scale. The shoulder subluxation resolved, however, the strengths of the deltoid and infraspinatus remained almost M1. At the most recent clinical examination, the patient was 18 years old and the active range of motion of patient's left elbow was 0°-125°, and those of the whole shoulder girdle were abduction 35°, flexion 60°, extension 30° and external rotation 0°. CONCLUSIONS: The outcomes we achieved may support partial nerve transfer techniques as viable treatment options for persistent long-standing motor deficits following poliomyelitis-like palsy in children. However, we recommend performing partial nerve transfer as early as possible after recovery from flaccid paralysis and also use of nerves that derive from narrow spinal cord segments. After denervation, children's neuromuscular systems seem to have the ability to regenerate after a much longer period than has generally been believed. This speculation is based on only a single case report; thus, more experience is needed before this generalization can confidently be made.

Transformation of Block Copolymer Nanoparticles from Ellipsoids with Striped Lamellae into Onionlike Spheres and Dynamical Control via Coupled Cahn-Hilliard Equations.

Annealing of block copolymers has become a tool of great importance for the reconfiguration of nanoparticles. Here, we present the experimental results of annealing block copolymer nanoparticles and a theoretical model to describe the morphological transformation of ellipsoids with striped lamellae into onionlike spheres. A good correspondence between the experimental findings and predictions of the model was observed. The model based on finding the steepest direction of descent of an appropriate free energy leads to a set of Cahn-Hilliard equations that correctly describe the dynamical transformation of striped ellipsoids into onionlike spheres and reverse onionlike particles, regardless of the nature of the annealing process. This universality makes it possible to describe a variety of experimental conditions involving nanoparticles underlying a heating process. A notable advantage of the proposed approach is that it enables selective control of the interaction between the confined block copolymer and the surrounding medium. This feature endows the model with a great versatility to enable the reproduction of several combined effects of surfactants in diverse conditions, including cases with reverse affinities for the block copolymer segments. A phase diagram to describe a variety of morphologies is presented. We employ the relationship between the temperature-dependent Flory-Huggins parameter and the width of the interfaces to account for changes in temperature due to the heating process. Simulation results correctly show how the transformation evolves as the temperature increases. This increment in temperature corresponds to progressively smaller values of the interfacial width. We anticipate that the proposed approach will facilitate the design and more precise control of experiments involving various kinds of annealing processes.

Achilles' heel of a traveling pulse subject to a local external stimulus.

The response of a traveling pulse to a local external stimulus is considered numerically for a modified three-component Oregonator, which is a model system for the photosensitive Belousov-Zhabotinsky (BZ) reaction. The traveling pulse is traced and constantly stimulated, with the distance between the pulse and the stimulus being kept constant. We are interested in the minimal strength of the spatially localized stimulus in order to eliminate the pulse. The use of a stimulus of small width allows us to detect the point in the pulse most sensitive to the external stimulus, referred to as the "Achilles' heel" of the traveling pulse, at which minimal strength of stimulus causes a collapse of the pulse. Our findings are demonstrated experimentally as well with the photosensitive BZ reaction.

Theta-alpha EEG phase distributions in the frontal area for dissociation of visual and auditory working memory.

Working memory (WM) is known to be associated with synchronization of the theta and alpha bands observed in electroencephalograms (EEGs). Although frontal-posterior global theta synchronization appears in modality-specific WM, local theta synchronization in frontal regions has been found in modality-independent WM. How frontal theta oscillations separately synchronize with task-relevant sensory brain areas remains an open question. Here, we focused on theta-alpha phase relationships in frontal areas using EEG, and then verified their functional roles with mathematical models. EEG data showed that the relationship between theta (6 Hz) and alpha (12 Hz) phases in the frontal areas was about 1:2 during both auditory and visual WM, and that the phase distributions between auditory and visual WM were different. Next, we used the differences in phase distributions to construct FitzHugh-Nagumo type mathematical models. The results replicated the modality-specific branching by orthogonally of the trigonometric functions for theta and alpha oscillations. Furthermore, mathematical and experimental results were consistent with regards to the phase relationships and amplitudes observed in frontal and sensory areas. These results indicate the important role that different phase distributions of theta and alpha oscillations have in modality-specific dissociation in the brain.

The relationship between preoperative needle electromyography findings and muscle power restoration after surgery in severe carpal tunnel syndrome patients.

PURPOSE: Needle electromyography provides essential information about the functional aspects of the muscle. But little attention has been given in the literature to needle electromyography examinations in carpal tunnel syndrome. We examined the relationship between preoperative needle electromyography findings and functional recovery of the abductor pollicis brevis (APB) muscle in severe carpal tunnel syndrome patients. METHODS: The subjects of this study were 49 patients, 58 hands, who fit the following 5 criteria: (1) idiopathic carpal tunnel syndrome; (2) pre-op MMT grade of the APB muscle was M0 or M1; (3) APB-CMAP (compound muscle action potential) was not evoked in a median nerve conduction study; (4) needle electromyography of the APB muscle had been done; (5) underwent carpal tunnel release only. The patients were divided into two groups according to the results of pre-op needle electromyography: voluntary motor unit potential of the APB muscle was evoked [MUP(+) group]or not [MUP(-) group]. We evaluated APB muscle strength at one year after surgery, and patient satisfaction and functional evaluations (CTSI-FS) at more than one year after. RESULTS: The APB muscle recovery rate to M3 or higher was 100% in the MUP(+) group, and 57% in the MUP(-) group. Patient satisfaction was also high and functional recovery was sufficient in the MUP(+) group. No patients requested a second opponensplasty. CONCLUSION: Our findings suggest that post-op restoration of thumb function relates to whether or not the MUP ofthe APB muscle is evoked. Single-stage opponensplasty may be unnecessary if the MUP of the APB muscle is; evoked. Needle electromyography is therefore useful in consideration for opponensplasty. LEVEL OF EVIDENCE: Level Ⅲ, case-control study.

Correction: Frustrated phases under three-dimensional confinement simulated by a set of coupled Cahn-Hilliard equations.

Correction for 'Frustrated phases under three-dimensional confinement simulated by a set of coupled Cahn-Hilliard equations' by Edgar Avalos et al., Soft Matter, 2016, 12, 5905-5914.

Frustrated phases under three-dimensional confinement simulated by a set of coupled Cahn-Hilliard equations.

We numerically study a set of coupled Cahn-Hilliard equations as a means to find morphologies of diblock copolymers in three-dimensional spherical confinement. This approach allows us to find a variety of energy minimizers including rings, tennis balls, Janus balls and multipods among several others. Phase diagrams of confined morphologies are presented. We modify the size of the interface between microphases to control the number of holes in multipod morphologies. Comparison to experimental observation by transmission electron microtomography of multipods in polystyrene-polyisoprene diblock copolymers is also presented.

Hierarchical structures of amorphous solids characterized by persistent homology.

This article proposes a topological method that extracts hierarchical structures of various amorphous solids. The method is based on the persistence diagram (PD), a mathematical tool for capturing shapes of multiscale data. The input to the PDs is given by an atomic configuration and the output is expressed as 2D histograms. Then, specific distributions such as curves and islands in the PDs identify meaningful shape characteristics of the atomic configuration. Although the method can be applied to a wide variety of disordered systems, it is applied here to silica glass, the Lennard-Jones system, and Cu-Zr metallic glass as standard examples of continuous random network and random packing structures. In silica glass, the method classified the atomic rings as short-range and medium-range orders and unveiled hierarchical ring structures among them. These detailed geometric characterizations clarified a real space origin of the first sharp diffraction peak and also indicated that PDs contain information on elastic response. Even in the Lennard-Jones system and Cu-Zr metallic glass, the hierarchical structures in the atomic configurations were derived in a similar way using PDs, although the glass structures and properties substantially differ from silica glass. These results suggest that the PDs provide a unified method that extracts greater depth of geometric information in amorphous solids than conventional methods.

Florigen distribution determined by a source-sink balance explains the diversity of inflorescence structures in Arabidopsis.

The ability to continue flowering after loss of inductive environmental cues that trigger flowering is termed floral commitment. Reversible transition involving a switch from floral development back to vegetative development has been found in Arabidopsis mutants and many plant species. Although the molecular basis for floral commitment remains unclear, recent studies suggest that the persistent activity of FLOWERING LOCUS T (FT) at inflorescences is required for floral commitment in Arabidopsis thaliana. Because FT encodes a mobile signal, florigen, which is generally transported from leaves to meristems through the phloem, understanding the transportation dynamics of FT is required to explore the role of FT on floral commitment. Here we developed a transportation model of leaf- and inflorescence-derived florigen and sucrose based on pressure-flow hypothesis. Depending on the demanded level of florigen supply for floral commitment of each floral meristem, the model predicted the change in inflorescence pattern from stable commitment to flower, transient flowering, and complete reversion. FT activity in inflorescence partly suppressed floral reversion, but complete suppression was achieved only when inflorescence became a source of sucrose. This finding highlights the importance of monitoring the spatio-temporal sucrose distribution and floral stimulus to understand inflorescence development mechanism.

Persistent homology and many-body atomic structure for medium-range order in the glass.

The characterization of the medium-range (MRO) order in amorphous materials and its relation to the short-range order is discussed. A new topological approach to extract a hierarchical structure of amorphous materials is presented, which is robust against small perturbations and allows us to distinguish it from periodic or random configurations. This method is called the persistence diagram (PD) and introduces scales to many-body atomic structures to facilitate size and shape characterization. We first illustrate the representation of perfect crystalline and random structures in PDs. Then, the MRO in amorphous silica is characterized using the appropriate PD. The PD approach compresses the size of the data set significantly, to much smaller geometrical summaries, and has considerable potential for application to a wide range of materials, including complex molecular liquids, granular materials, and metallic glasses.