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The present work introduces a deep learning approach to describe the perturbations of the pressure and radius in arterial blood flow. A mathematical model for the simulation of viscoelastic arterial flow is developed based on the assumption of long wavelength and large Reynolds number. Then, the reductive perturbation method is used to derive nonlinear evolutionary equations describing the resistance of the medium, the elastic properties, and the viscous properties of the wall. Using automatic differentiation, the solutions of nonlinear evolutionary equations at different time scales are represented using state-of-the-art physics-informed deep neural networks that are trained on a limited number of data points. The optimal neural network architecture for solving the nonlinear partial differential equations is found by employing Bayesian Hyperparameter Optimization. The proposed technique provides an alternate approach to avoid time-consuming numerical discretization methods such as finite difference or finite element for solving higher order nonlinear partial differential equations. Additionally, the capability of the trained model is demonstrated through graphs, and the solutions are also validated numerically. The graphical illustrations of pulse wave propagation can provide the correct interpretation of cardiovascular parameters, leading to an accurate diagnosis and successful treatment. Thus, the findings of this study could pave the way for the rapid development of emerging medical machine learning applications. • The present work introduces a deep learning approach to describe the arterial blood flow. • An overview of deep learning-based solutions of nonlinear PDEs and error analysis of the proposed model has been described. • The prime factors such as medium resistance, elastic properties, and viscosity of the wall were taken into account. • The predicted solutions of the PDEs in the form of pressure pulses and solitary waves are discussed graphically. • The proposed technique provides an alternative approach to numerical methods for solving higher-order nonlinear PDEs. [ABSTRACT FROM AUTHOR]

Dorsal plate fixation of proximal phalanx (PP) fractures is a conventional approach but interferes with the extensor mechanism and results in stiffness. Biomechanical studies have shown that laterally placed plates on the proximal phalanges are equally stable and rigid. This technique obviates the issue of tendon adhesion and may result in better postoperative range of motion and lower secondary procedures such as removal of implant and tenolysis. The low adoption of this technique may be related to lack of familiarity with the surgical approach. We describe our surgical technique with lateral plating of PP fractures and present our case that lateral plate osteosynthesis is an acceptable surgical fixation option for PP fractures, which extends the hand surgeon’s armamentarium for more challenging and comminuted fractures.

Acute tendon and bony injuries of the distal phalanx are challenging injuries because they may result in chronic pain, hypersensitivity, stiffness, and deformity if they are not adequately treated. Flexor tendon avulsions require early surgical repair. Conversely, most extensor tendon injuries and fractures heal well with nonoperative treatment. However, surgery is indicated in selected patients, and meticulous technique is required to achieve good postoperative outcomes. In this article, we outline the pertinent clinical anatomy of the distal phalanx, review the current literature regarding treatment options, and highlight key management points to ensure good clinical outcomes while minimizing complications.

Singapore as an island nation is one of three countries in the world that has hand and reconstructive microsurgery (HRM) as an independent specialty. The 52 accredited hand surgeons serving a population of 5.7 million facilitate hassle free access to patients. Hand surgery historically is rooted very much in orthopaedic surgery as in most Asian countries with more than five decades of rapid evolution. Singapore pioneered a structured and systematic training program for HRM and the local surgeons have contributed significantly to the body of knowledge in hand surgery with targeted research and publications with three surgeons being awarded international recognition for their contributions. Singapore continues to contribute significantly to surgical volunteerism regionally through active involvement in the training of regional surgeons through their sustainable volunteer activities and through international fellowships in Singapore hospitals. The future of hand surgery in Singapore will be more competency and multidiscipline based on community-centered approach.

Structural characterization in on-surface synthesis is primarily carried out by Scanning Probe Microscopy (SPM) which provides high lateral resolution. Yet, important fresh perspectives on surface interactions and molecular conformations are gained from adsorption heights that remain largely inaccessible to SPM, but can be precisely measured with both elemental and chemical sensitivity by Normal-Incidence X-ray Standing Wave (NIXSW) analysis. Here, we study the evolution of adsorption heights in the on-surface synthesis and post-synthetic decoupling of porous covalent triazine–phenylene networks obtained from 2,4,6-tris(4-bromophenyl)-1,3,5-triazine (TBPT) precursors on Ag(111). Room temperature deposition of TBPT and mild annealing to ∼150 °C result in full debromination and formation of organometallic intermediates, where the monomers are linked into reticulated networks by C–Ag–C bonds. Topologically identical covalent networks comprised of triazine vertices that are interconnected by biphenyl units are obtained by a thermally activated chemical transformation of the organometallic intermediates. Exposure to iodine vapor facilitates decoupling by intercalation of an iodine monolayer between the covalent networks and the Ag(111) surface. Accordingly, Scanning Tunneling Microscopy (STM), X-ray Photoelectron Spectroscopy (XPS) and NIXSW experiments are carried out for three successive sample stages: organometallic intermediates, covalent networks directly on Ag(111) and after decoupling. NIXSW analysis facilitates the determination of adsorption heights of chemically distinct carbon species, i.e.in the phenyl and triazine rings, and also for the organometallic carbon atoms. Thereby, molecular conformations are assessed for each sample stage. The interpretation of experimental results is informed by Density Functional Theory (DFT) calculations, providing a consistent picture of adsorption heights and molecular deformations in the networks that result from the interplay between steric hindrance and surface interactions. Quantitative adsorption heights, i.e.vertical distances between adsorbates and surface, provide detailed insight into surface interactions, but are underexplored in on-surface synthesis. In particular, the direct comparison with an in situprepared decoupled state unveils the surface influence on the network structure, and shows that iodine intercalation is a powerful decoupling strategy.

There are multiple options available for reconstruction of soft tissue defects of the digits. The main goal of reconstruction is to achieve normal or near-normal mobility. Soft tissue defects can be considered in the following groups: fingertip, nonfingertip, and multiple digits. The choice of reconstruction for fingertip defects depends primarily on the amount of volar skin available. The patient’s functional demands and expectations, and the expertise of the surgeon, also determine the reconstructive strategy.

Soft tissue defects of the hand commonly arise as a consequence of trauma or infection and after resection of tumors. Restoring a thin and pliable soft tissue envelope is critical to restoring mobility and optimizing functional outcomes. The appearance, color, and texture match as well as donor site issues are increasingly important aspects of hand reconstruction. This article discusses the principles of soft tissue reconstruction in the hand and presents a rational approach to clinical decision making to ensure optimal outcomes.

In this study, a single- and discrete-phase models are used to obtain the analytical expressions of velocity, temperature, wall shear stress and stream function, to delineate the transport characteristics of Newtonian gold–blood nanofluid flowing through stenosed artery in the presence of magnetic field. The spherical gold nanoparticles are used in discrete-phase analysis for tracking the nanoparticle in the blood flow through multiple stenoses, which is not explored so far. The effect of various flow parameters on velocity profile, wall shear stress and stream function is demonstrated through mathematically and graphically for different values of interest. The effect of nanoparticle volume fraction in the presence and absence of external magnetic field is investigated. The results demonstrate that with an increase in the particle concentration in the presence of magnetic field, the temperature of the nanofluid and wall shearing stress are increased, whereas the velocity is decreased. The significant effect of Brownian motion is observed on gold nanoparticle in discrete-phase model. This study would provide valuable information for nanoparticle distribution in a vascular artery in the field of nanoparticle drug delivery for treatment of stenotic diseases.

The silver(I) catch–release system composed of nanoswitch 1and the anthracene-appended crown ether 2is infallibly driven by chemical triggers and ion transfer. Any state of the silver(I) translocation is self-reported by a ratiometric emission signature at 472 and 554 nm. In the self-sorted networked state I, the silver(I) ions are tightly shielded inside nanoswitch [Ag(1)]+(“catch”) so that their catalytic activity is zero while emission at 554 nm is maximum. Addition of zinc(II) releases silver(I) from [Ag(1)]+and generates the catalytically active and fluorescent complex [Ag(2)]+. In this networked state II (“release”) both catalytic activity and emission at 472 nm are maximum. Removal of the original trigger regenerates networked state I. ON/OFF control and recycling of catalyst was demonstrated over three in situcycles.

The reversible photoisomerization of azobenzene has been utilized to construct a plethora of systems in which optical, electronic, catalytic, and other properties can be controlled by light. However, owing to azobenzene’s hydrophobic nature, most of these examples have been realized only in organic solvents, and systems operating in water are relatively scarce. Here, we show that by coadsorbing the inherently hydrophobic azobenzenes with water-solubilizing ligands on the same nanoparticulate platforms, it is possible to render them essentially water-soluble. To this end, we developed a modified nanoparticle functionalization procedure allowing us to precisely fine-tune the amount of azobenzene on the functionalized nanoparticles. Molecular dynamics simulations helped us to identify two distinct supramolecular architectures (depending on the length of the background ligand) on these nanoparticles, which can explain their excellent aqueous solubilities. Azobenzenes adsorbed on these water-soluble nanoparticles exhibit highly reversible photoisomerization upon exposure to UV and visible light. Importantly, the mixed-monolayer approach allowed us to systematically investigate how the background ligand affects the switching properties of azobenzene. We found that the nature of the background ligand has a profound effect on the kinetics of azobenzene switching. For example, a hydroxy-terminated background ligand is capable of accelerating the back-isomerization reaction by more than 6000-fold. These results pave the way toward the development of novel light-responsive nanomaterials operating in aqueous media and, in the long run, in biological environments.

In the present study, a single and discrete phase model is employed to obtain analytical solutions of velocity, temperature, and stream function to describe the transport characteristics of a newtonian blood-gold, silver, or copper nanofluid flowing through an inclined multiple stenose artery, under the influence of externally applied heat. The spherical gold nanoparticles are used for discrete phase model to track the nanoparticle in the blood flow within the artery containing multiple stenosis, which is not explored so far. Apart from estimating the velocity, temperature distributions, and stream function, an explicit expression is derived for wall shear stress distribution. The effects of different flow parameters are depicted through graphs for different values of interest. The results reveal that the hemodynamics effects of stenosis reduce with an increase of particle concentration in the blood and also finding that the drug gold nanoparticles are more effective to reduce hemodynamics of stenosis when compared to the drug silver or copper nanoparticle. The normal flow of blood is observed for only 0.03 volume fraction of gold nanoparticle. We also demonstrate that cylindrical-shaped nanoparticle is more effective for drug delivery than spherical shaped as it has less wall shearing stress. The significant effect of Brownian motion is observed on gold nanoparticle in two-phase model. This study would provide valuable information for nanoparticle distribution in a vascular artery in the field of nanoparticle drug delivery.

Abiotic foldamers, that is foldamers that have backbones chemically remote from peptidic and nucleotidic skeletons, may give access to shapes and functions different to those of peptides and nucleotides. However, design methodologies towards abiotic tertiary and quaternary structures are yet to be developed. Here we report rationally designed interactional patterns to guide the folding and assembly of abiotic helix bundles. Computational design facilitated the introduction of hydrogen-bonding functionalities at defined locations on the aromatic amide backbones that promote cooperative folding into helix–turn–helix motifs in organic solvents. The hydrogen-bond-directed aggregation of helices not linked by a turn unit produced several thermodynamically and kinetically stable homochiral dimeric and trimeric bundles with structures that are distinct from the designed helix–turn–helix. Relative helix orientation within the bundles may be changed from parallel to tilted on subtle solvent variations. Altogether, these results prefigure the richness and uniqueness of abiotic tertiary structure behaviour.

The study investigates the phenomenon of wave diffraction by multiple poroelastic plates in infinitely deep water using the two-dimensional linearized potential theory. The study focuses on numerically computing the reflection and transmission coefficients using Galerkin approximations specifically designed for two nonidentical vertical poroelastic plates. By varying the separation lengths, porosity, and flexural rigidity of the plates, the study explores the hydrodynamic quantities associated with the wave-plate interaction. These quantities are then represented graphically to visualize their behavior under different conditions. The results of the study show that the flexural rigidity of the porous plates has a significant effect on wave reflection and transmission. The correctness of the method used in the study is confirmed by comparing the results available in the literature. Overall, the study provides valuable insights into the behavior of waves interacting with multiple poroelastic plates and highlights the importance of considering the flexural rigidity of the plates in such systems. The numerical approach used in the study can also be applied to other similar problems and can provide a useful tool for predicting the behavior of waves in complex systems.

Soft tissue defects of the hand may result from trauma, infection, vascular disease, and after resection of tumors. Microsurgery has evolved to a stage where it is relatively commonplace today but procedures such as free flaps still incur significant time, manpower, cost, and material resources. The aim of this article is to articulate the specific situations in hand reconstruction when microsurgery is superior to nonmicrosurgical reconstructive options. The benefits of microsurgical reconstruction include a variety of important metrics, such as improved function, better tissue match, less donor site morbidity, and reduced downtime for the patient.

The non-linear blood flow under the influence of periodic body acceleration through a generalized multiple stenosed artery is investigated with the help of numerical simulation. The arterial segment is simulated by a cylindrical tube filled with a viscous incompressible Newtonian fluid described by the Navier–Stokes equation. The non-linear equation is solved numerically using finite difference with the proper boundary conditions and pressure gradient that arise from the heart. The effect of Reynolds number is also discussed. Results are shown in comparison with the existing models.

Purpose. To compare early versus late flap coverage for open tibial fractures.Methods. Medical records of 83 men and 6 women (mean age, 38 years) who underwent fixation for open tibial fractures (Gustilo grades IIIB and IIIC) followed by flap coverage within (n=30) or after (n=59) 72 hours were reviewed. All fractures were treated within 24 hours. Outcome measures included bone union, infection, flap failure, the need for secondary procedures to achieve union, and eventual amputation. The early and late flap coverage groups were compared.Results. Early flap coverage was associated with shorter length of hospitalisation (31.4 vs. 55.8 days, p<0.01), lower deep infection rates (23% vs. 54%, p<0.01), and smaller number of surgical procedures (6.4 vs. 9.2, p=0.01). The 2 groups did not differ significantly in terms of the time to bone union, flap failure, amputation, and the need of secondary procedures to facilitate bone union.Conclusion. In severe open tibial fractures, early soft-tissue coverage (within 72 hours) was associated with more favourable outcomes in terms of length of hospitalisation and infection.

Symptomatic osteochondromas (OCEs) of the proximal humerus present a number of challenges, based upon their location and proximity to neurovascular structures. The purpose of this investigation was to evaluate the characteristics of these lesions and report the early results of surgical excision in children.

The purpose of this investigation was to determine if leaving Kirschner wires exposed is more cost-effective than burying them subcutaneously after open reduction and internal fixation (ORIF) of humeral lateral condyle fractures.

Flip a switch: A nanoswitch uses chemical inputs to turn an organocatalytic Knoevenagel reaction on and off (see scheme: R=reactant, P=product). To stop catalysis the chemical input (pink and green) wraps around the inhibitory segment of the nanoswitch to effect release or unlocking of the switch. The process can run reversibly over three cycles without loss of activity.

Abstract: In this paper the classical problem of water wave scattering by two partially immersed plane vertical barriers submerged in deep water up to the same depth is investigated. This problem has an exact but complicated solution and an approximate solution in the literature of linearised theory of water waves. Using the Havelock expansion for the water wave potential, the problem is reduced here to solving Abel integral equations having exact solutions. Utilising these solutions, two sets of expressions for the reflection and transmission coefficients are obtained in closed forms in terms of computable integrals in contrast to the results given in the literature which involved six complicated integrals in terms of elliptic functions. The two different expressions for each coefficient produce almost the same numerical results although it has not been possible to prove their equivalence analytically. The reflection coefficient is depicted against the wave number in a number of figures which almost coincide with the figures available in the literature wherein the problem was solved approximately by employing complementary approximations. [Copyright &y& Elsevier]

Abstract: This paper provides a mathematical investigation of the problem of scattering of surface water waves by two surface-piercing barriers that are almost vertical and are described by the same shape function in the context of linear theory by employing a simplified perturbational analysis. Green’s identity is used to express the perturbation to the quantities of interest—the reflection and transmission coefficients—in terms of the solution to the unperturbed system. As in the case of single nearly vertical barrier, here also the perturbed transmission coefficient vanishes identically while the perturbed reflection coefficient is obtained in terms of a number of definite integrals involving shape function. When the two barriers are merged into a single barrier, the known result for a single barrier is recovered. [Copyright &y& Elsevier]

An appropriate nonlinear blood flow model under the influence of periodic body acceleration through a multiple stenosed artery is investigated with the help of finite difference method. The arterial segment is simulated by a cylindrical tube filled with a viscous incompressible Newtonian fluid described by the Navier-Stokes equation. The nonlinear equation is solved numerically with the proper boundary conditions and pressure gradient that arise from the normal functioning of the heart. Results are discussed in comparison with the existing models.

Review: 99 refs.