Radial Counterpart Research Articles

Wood-inspired highly anisotropic scaffold activated with in situ mineralized collagen for advanced bone regeneration

Addressing bone defects, limited by inherent regenerative capacities, has catalyzed the development of biomimetic scaffolds. Despite the extensive exploration of collagen-hydroxyapatite scaffolds, they frequently fail to accurately replicate the intricate nanostructure of natural bone. We introduce the wood-collagen- hydroxyapatite (WCH) scaffold, a novel biomimetic structure inspired by the analogous architectures of wood and bone, aimed at substantially improving bone regeneration. Comprising a wood-based matrix, collagen interface, and hydroxyapatite mineralization, the WCH scaffold embodies the critical components of bone tissue. The scaffold’s wood-derived framework imparts an anisotropic structure and notable mechanical strength, closely mimicking natural bone’s nanoarchitecture. Significantly, the scaffold’s longitudinal (L) orientation outperforms its radial counterpart in biocompatibility and bioactivity, reflecting bone’s directional properties and promoting superior cell proliferation, adhesion, and osteogenic differentiation. Validated in a rabbit femur defect model, the L directional WCH scaffold significantly accelerated new bone formation, tissue ingrowth, and bone tissue maturation. This innovative wood-inspired scaffold, characterized by its highly anisotropic structure and enhanced with in-situ mineralized collagen, holds significant promise for advancing bone regeneration techniques.

Implicit Large-eddy Simulations of Global Solar Convection: Effects of Numerical Resolution in Nonrotating and Rotating Cases

Simulating deep solar convection and its coupled mean-field motions is a formidable challenge where few observational results constrain models that suffer from the nonphysical influence of the grid resolution. We present hydrodynamic global implicit large-eddy simulations of deep solar convection performed with the EULAG-MHD code, and we explore the effects of grid resolution on the properties of rotating and nonrotating convection. The results, based on low-order moments and turbulent spectra, reveal that convergence in nonrotating simulations may be achieved at resolutions not much higher than these considered here. The flow is highly anisotropic, with the energy contained in horizontal divergent motions exceeding their radial counterpart by more than three orders of magnitude. By contrast, in rotating simulations, the largest energy is in the toroidal part of the horizontal motions. As the grid resolution increases, the turbulent correlations change in such a way that a solar-like differential rotation, obtained in the simulation with the coarser grid, transitions to an antisolar differential rotation. The reason for this change is the contribution of the effective viscosity to the balance of the forces driving large-scale flows. As the effective viscosity decreases, the angular momentum balance improves, yet the force balance in the meridional direction lessens, favoring a strong meridional flow that advects angular momentum toward the poles. The results suggest that obtaining the correct distribution of angular momentum may not be a mere issue of numerical resolution. Accounting for additional physics, such as magnetism or the near-surface shear layer, may be necessary in simulating the solar interior.

Design of hybrid solar cell with GaAs1−xBix (x = 0.01) nanowire core and conformally coated P3HT/ITO shell

The optoelectronic characteristics of the vertically aligned conformally coated radial junction, core–shell nanowire (NW) hybrid solar cell (HSC) having a core active layer of GaAs0.99Bi0.01as acceptor and donor shell layer of poly(3-hexylthiophene-2,5-diyl) (P3HT), have been investigated. Since axial junction solar cells (SCs) have been experimentally showing better efficiency as compared to their radial counterpart, our objective is to improve the efficiency of radial pn junction nanowire solar cells. In order to achieve that, the geometrical parameters, including the core diameter, shell thickness comprising P3HT layer and ITO for a fixed pitch of 480 nm are optimized. A fixed thickness of 10 nm is considered for P3HT due to a diffusion length of 20 nm. 3D finite-difference time-domain (FDTD) method has been employed to examine the effect of geometrical parameter variation on carrier generation and a detailed study has been presented. The core diameter of our proposed structure is 160 nm (Rcore = 80 nm) and the thickness of the surrounding shell is considered to be 90 nm (Rshell = 90 nm) for further optoelectronic performance study. The absorption spectra, generation rate profile and electric field profiles for the wavelength (λ) range of 400–900 nm have been presented for depicting the improvement caused due to incorporation of conformal coating of P3HT on core GaAs0.99Bi0.01 NW. An extensive investigation on the variation of electrical performance parameters such as open circuit voltage (Voc), short circuit current (Jsc), fill factor (FF) and power conversion efficiency (PCE) with carrier lifetime and surface recombination velocity (SRV) is performed for a fixed core and shell doping. An efficiency of 19% is achieved for the device featuring minority carrier lifetime of 60 ns and sufficiently high SRV of 105cm/s at the contacts for lightly doped core (∼1 × 1016 cm−3) and heavily doped shell (∼1 × 1019 cm−3) and substrate (∼1 × 1019 cm−3).

Exact separation of radial and angular correlation energies in two-electron atoms

Partitioning of helium atom’s correlation energy into radial and angular contributions, although of fundamental interest, has eluded critical scrutiny. Conventionally, radial and angular correlation energies of helium atom are defined for its ground state as deviations, from Hartree-Fock and exact values, of the energy obtained using a purely radial wavefunction devoid of any explicit dependence on the interelectronic distance. Here, we show this rationale to associate the contribution from radial-angular coupling entirely to the angular part underestimating the radial one, thereby also incorrectly predict non-vanishing residual radial probability densities. We derive analytic matrix elements for the high-precision Hylleraas basis set framework to seamlessly uncouple the angular correlation energy from its radial counterpart. The resulting formula agrees with numerical cubature yielding precise purely angular correlation energies for the ground as well as excited states. Our calculations indicate 60.2% of helium’s correlation energy to arise from strictly radial interactions; when excluding the contribution from the radial-angular coupling, this value drops to 41.3%.

Appraisal of the Free Ulnar Flap Versatility in Craniofacial Soft-tissue Reconstruction.

Summary:The unique anatomical characteristics of the forearm region make it especially popular as a free flap donor site for craniofacial soft-tissue reconstruction. The free ulnar forearm flap is less hirsute and allows for better concealment of donor site scar as compared with its radial counterpart. Despite these factors, the free radial forearm flap remains more popular among reconstructive surgeons. Through the presented case series, we hope to emphasize the versatile nature of the free ulnar forearm flap in addressing various craniofacial soft-tissue defects. Following institutional review board approval, a retrospective review of the senior authors' clinical experience performing microvascular free ulnar forearm flap reconstruction of craniofacial soft-tissue defects was performed. A total of 10 patients were identified through our review. Soft-tissue defect locations included lower eyelid (n = 2), tongue and floor of mouth (n = 2), lower lip (n = 2), palatopharyngeal area (n = 1), nose (n = 1), and palate (n = 1). Trauma was the most common defect etiology (n = 5), followed by malignancy (n = 4), and iatrogenic injury in 1 case. All patients demonstrated good aesthetic and functional outcomes related to vision, speech, and oral intake at follow-up when applicable. The free ulnar forearm flap is a versatile reconstructive option that can be used to address a wide spectrum of craniofacial soft-tissue defects and offers numerous advantages over its radial counterpart.

Pattern of variations in superficial palmar arch in 134 Negro cadaveric hands.

To investigate the incidence of anatomical variations of superficial palmar arch in Negro population. A total of 134 upper limbs comprising 74 right and 60 left specimens embalmed with formaldehyde were used for the investigation. The hand was dissected with palmar aponeurosis identified and removed to expose the ulnar and radial arteries. A complete superficial arch was observed in 73.9% specimens. In 70.1% cases the superficial branch of the ulnar artery communicated with its radial arterial counterpart. In 3.0% cases the arch was formed entirely by the ulnar artery while in a single case (0.8%), a rare pattern was observed in which the superficial palmar branch of the ulnar artery gave rise to the princeps pollicis artery as its terminal branch with the exclusion of radialis indicis that had its origin from deep palmar branch of radial artery. The incomplete arch constituted 26.1% of the entire palmar arch formation. In our Negro population study, deviation from normal anatomical pattern was common. Therefore, a review of vascular pattern prior to invasive or intervention surgery is strongly recommended to be able to detect anomalies likely to necessitate modification of surgical procedures.

Design and simulation of disk stepper motor with permanent magnets

Abstract In this paper the design and the magneto-static simulation of axial-flux permanent- magnet stepper motor with the disc type rotor is presented. Disk motors are particularly suitable for electrical vehicles, robots, valve control, pumps, centrifuges, fans, machine tools and manufacturing. The brushless machine with axial flux and permanent magnets, also called the disc-type machine, is an interesting alternative to its cylindrical radial flux counterpart due to the disk shape, compact construction and high torque density. This paper describes a design of four phase microstepping motor with the disc type rotor. The FEM modeling and the 3D magneto-static simulation of the disk stepper motor with permanent magnets is being subject of the article, too. Disc rotor type permanent magnet stepper motor for high torque to inertia ratio is ideal for robotics and CNC machines.

Solving granular segregation problems using a biaxial rotary mixer

Granular mixing is a critical but poorly understood aspect in the manufacture of many industrial products, for example, pharmaceuticals, food, cosmetics, ceramics, fertilizer and polymers. The mixing and segregation phenomenon occur in most systems of granular solids and have a significant influence on the quality and outcome of the final product. The usual approach to mix the powders is by using a tumbling blender which rotates around one axis, where, the radial convection is reported to be faster than axial dispersion transport, hindering the mixing performance. A double cone mixer is fabricated which rotates around two axes, causing axial mixing competitive to its radial counterpart. Samples are collected intrusively using the discrete pocket samplers to quantify the characteristics of mixing for millimeter sized glass beads. Digital video recording and MATLAB based image analysis techniques are used for non-intrusive characterization of mixing in micron sized art sands. A parametric study of the effect of particle size, vessel speeds on the granular mixing is accomplished. Incorporation of dual axis rotation enhances axial mixing by 70–90% in comparison to single axis rotation. Particles of smaller sizes (art sand) tend to mix quicker than the bigger particles (glass beads) due to mild cohesive effects.

Radial and non-radial decompositions of Luenberger productivity indicator with an illustrative application

Viewing slacks as one possible source of inefficiency, and that inputs have differential importance in the production process, this paper develops, based on the directional Russell measure of inefficiency, the non-radial Luenberger indicator. This indicator is then shown as the sum of the individual input-specific Luenberger indicators. The Luenberger indicator and its various input-specific indicators are also then shown as the composite measure of efficiency change and technical change. This decomposition enables the researcher to empirically examine the contributions of each factor input towards the productivity change and its components—efficiency change and technical change. Our proposed decomposition scheme is then empirically illustrated to analyze the eco-productivity performance behavior of the 22 OECD countries during the period 1995–2004. Our results indicate that first, the productivity change estimates yielded from the non-radial Luenberger indicator are different from those yielded from its radial counterpart, when slacks are present; second, most of these countries are found experiencing productivity growth due to technical progress alone; and finally, as regards the order of input-specific contributions towards productivity growth, capital contributes the most, followed by savings in emissions and labor, respectively.

Investigating mixing in a multi-dimensional rotary mixer: Experiments and simulations

Mixing is an important but poorly understood aspect in petrochemical, food, ceramics, fertilizer and pharmaceutical processing and manufacturing. Segregation and mixing phenomenon occur in most systems of powdered or granular solids and have a significant influence on their behavior. Deliberate mixing of granular solids is an essential operation in the production of industrial powder products usually constituted from different ingredients. The knowledge of particle flow and mixing in a blender is critical to optimize the design and operation. Since performance of the product depends on blend homogeneity, the consequence of variability can be detrimental. A common approach to powder mixing is to use a tumbling blender, which is essentially a hollow vessel horizontally attached to a rotating shaft. This single axis rotary blender is one of the most common batch mixers among in industry, and finds use in myriad of application as dryers, kilns, coaters, mills and granulators. In most of the rotary mixers, the radial convection is faster than axial dispersion transport. This slow dispersive process hinders mixing performance in many blending, drying and coating applications. A double cone mixer is designed and fabricated which rotates around two axes, causing axial mixing competitive to its radial counterpart. Discrete Element Method (DEM) based numerical model is developed to simulate the granular flow within the mixer. Digitally recorded mixing states from experiments are used to fine-tune the numerical model. Discrete pocket samplers are also used in the experiments to quantify the characteristics of mixing. A parametric study of the effect of initial loading, particle size, fill ratio, vessel speeds, on the granular mixing is investigated by experiments and numerical simulation. Incorporation of dual axis rotation enhances axial mixing by 60 to 90% in comparison to single axis rotation. Mixing is achieved faster with front–back initial loading than with side–side loading. Particle size and fill level are found to have no significant effect on mixing characteristics.

A fast, robust method for detecting and characterizing azimuthal anisotropy with marinePSconverted waves, and its application to the west Svalbard continental slope

SUMMARY A method for using PS converted waves to detect and characterize azimuthal seismic anisotropy is developed, and applied to four-component ocean-bottom seismometer data acquired near the base of the continental slope west of Svalbard. The method determines the distribution of coherent signal vibrating perpendicular to the sagittal plane (the transverse direction), and employs an optimized rotation technique to separate the effects of anisotropy from other contributions to the seismic amplitude. The magnitude of the PS-wave transverse amplitude, when normalized by its radial counterpart, is shown to correspond to the degree of ellipticity of particle motions and is used to constrain the anisotropic symmetry class in the near-surface sediments. Results indicate the presence of orthorhombic or horizontal, transversely isotropic symmetry that is consistent with the presence of near-vertical, aligned cracks. From its orientation, the observed anisotropy is associated with: (1) gravitational, downslope stresses in the sediment sequence, which dips by approximately two degrees to the SW and (2) tectonic stresses associated with the segmented spreading centres of the northern Knipovich Ridge, which spread in the NW–SE direction. Aligned cracks are likely to influence the local distribution of gas hydrate and free gas in these sediments. An investigation of the effect of seismic noise on optimized rotation shows that the vectorial combination of independent geophone records has variable sensitivity to source-related noise. This sensitivity peaks where the sagittal azimuth bisects the deployment orientation of the geophones on the seabed. A method to reduce the sensitivity to directional noise is developed and shown to improve the transverse amplitude plots. This approach to noise reduction may be used to improve the quality of seismic images derived from multicomponent data.

Model for stars of interacting bosons and fermions

In this paper we introduce a current-current type interaction term in the Lagrangian density of gravity coupled to complex scalar fields, in the presence of a degenerated Fermi gas. For low transferred momenta, such a term, which might account for the interaction among boson and fermion constituents of compact stellar objects, is subsequently reduced to a quadratic one in the scalar sector. This procedure enforces the use of a complex radial field counterpart in the equations of motion. The real and the imaginary components of the scalar field exhibit different behavior as the interaction increases. The results also suggest that the Bose-Fermi system undergoes a phase transition for a suitable choice of the coupling constant.

A polar co-ordinate system for positional information in the vertebrate neural retina

Pattern formation in many developing systems has been traditionally understood in terms of a prior signalling of positional information along mutually orthogonal axes, thus setting up a Cartesian co-ordinate grid. Existing data from the vertebrate neural retina has here been reinterpreted in terms of a non-Cartesian system. Results bearing on regeneration and duplication in eye fragments, “axial determination” and polarity alterations in fused eye fragments are considered and interpreted in terms of a polar co-ordinate system. On this model the position of each region of the retina is defined by a co-ordinate (radial) expressing distance from the centre and another (circumferential) expressing position around the circumference. The radial co-ordinate accords with the radial nature of retinal growth and it is possible that the spatially ordered sequence of cell divisions may itself specify the sequence of radial positions. The circumferential co-ordinate, unlike the radial counterpart, is specified in interaction with the extra-ocular tissue such that it may be oriented in the embryo with reference to a primary embryo Cartesian grid. The ability of the model to account for ultrastructural findings, problematic for the Cartesian model, is discussed.