Mode Profile Research Articles

Structural aspects of formetanate hydrochloride binding with human serum albumin using spectroscopic and molecular modeling techniques

Formetanate Hydrochloride (FMT), a highly potent chemical, acts as an insecticide, acaricide, and miticide to protect various fruits and vegetables. The widespread use elevates concern about its presence in the ecosystem, impact upon human health via interaction with biological receptors. Spectroscopic and molecular modeling techniques at different temperatures were used to investigate the binding of FMT with Human serum albumin (HSA) at the molecular level. The experimental and computational results have provided the binding affinity, binding mode, conformational flexibility, and thermodynamic profile of FMT-HSA complex. The FMT binding appears to be spontaneous, and entropy driven. Overall binding affinity of FMT falls within −7.29 to −4.67 Kcal M-1. FMT binds in domain I, subdomain IA of HSA and is stabilized by hydrophobic interactions. Molecular dynamics simulations of the FMT-HSA complex over 100 ns at 288 K, 298 K and 308 K indicated that FMT showed minor adjustments in conformation and placement within the binding site. While, MM/PBSA analysis of the complex provided individual contributions of energy terms. Quantum mechanical (QM) calculations were used to calculate absolute energy values of different poses of FMT which in turn showed minor variations in energy suggesting slight conformational variation in the bound form. The computational results are in agreement with experimental findings.

Curvilinear spin-wave dynamics beyond the thin-shell approximation: Magnetic nanotubes as a case study

Surface curvature of magnetic systems can lead to many static and dynamic effects which are not present in flat systems of the same material. These emergent magnetochiral effects can lead to frequency nonreciprocity of spin waves, which has been shown to be a bulk effect of dipolar origin and is related to a curvature-induced symmetry breaking in the magnetic volume charges. So far, such effects have been investigated theoretically mostly for thin shells, where the spatial profiles of the spin waves can be assumed to be homogeneous along the thickness. Here, using a finite-element dynamic-matrix approach, we investigate the transition of the spin-wave spectrum from thin to thick curvilinear shells, at the example of magnetic nanotubes in the vortex state. With increasing thickness, we observe the appearance of higher-order radial modes which are strongly hybridized and resemble the perpendicular-standing spin waves (PSSWs) in flat films. Along with an increasing dispersion asymmetry, we uncover the curvature-induced nonreciprocity of the mode profiles. This is explained in a very simple, general picture for thick curvilinear shells, considering the inhomogeneity of the emergent geometric volume charges along the thickness of the shell. Such curvature-induced mode-profile asymmetry also leads to nonreciprocal hybridization, which can facilitate unidirectional spin-wave propagation. With that, we also show how curvature allows for nonlinear three-wave splitting of a higher-order radial mode into secondary modes which can also propagate unidirectionally. We believe that our study provides a significant contribution to the understanding of the spin-wave dynamics in curvilinear magnetic systems, and also advertises these for novel magnonic applications.

Serious cycling-related fractures in on and off-road accidents: A retrospective analysis in the Australian Capital Territory region

Cycling is an increasingly popular activity which is widely supported by health advocates. In the last year, more than a third of Australians used a bike [1]. While road cycling remains popular, participation in off-road recreational cycling, including mountain biking, bicycle moto cross (BMX) riding, and outdoor leisure cycling, is increasing and this is associated with an increase in the number and cost of cycling injuries [2–5]. The aim of this study was to describe and compare contemporary patterns of cycling fracture requiring hospitalisation as a function of cycling mode in the Australian Capital Territory region.This retrospective analysis of cycling-related-fracture hospitalisations in the ACT region described data recorded between July 2012 and December 2019. Logistic regression models were used to calculate probabilities of sustaining a fracture at different sites for each of the cycling modes (on-road, mountain, BMX, leisure, unspecified). These likelihoods were then compared against the on-road fracture profile.Cycling-related-fracture hospitalisations increased by 32% in the seven years analysed. Of all fracture admissions, 442 (33%) were on-road, 658 (49%) off-road, and 242 (18%) unknown. The majority were male (79%), median age 37 (IQR 16, 52). Median length of stay was two days. The number of fractures per admission ranged from one to thirteen with a median of one. Wrist, clavicle, ribs, and skull were the four most frequent fracture sites for all cycling modes. Fracture profiles of on- and off-road accidents were similar, with the exception of wrist fractures which were more likely in off-road (OR 1.96, p < 0.01) and unspecified cycling accidents (OR 5.07, p < 0.01). Skull fractures comprised 19% of all BMX-related fractures. More than half of all fracture-related admissions required surgery.With increasing support for sustainable and healthy transport and recreation activities, the fracture profiles of different cycling modes must first be assessed in order to inform strategies to reduce and manage this injury burden.

Interplay of Leakage Radiation and Protection in Topological Photonic Crystal Cavities

AbstractThe introduction of topological concepts to the design of photonic crystal cavities holds great promise for applications in integrated photonics due to the prospect of topological protection. This study examines the signatures of topological light confinement in the leakage radiation of 2D topological photonic crystal cavities. The cavities are implemented in an all‐dielectric platform that features the photonic quantum spin Hall effect at telecom wavelengths and supports helical edge states that are weakly coupled to the radiation continuum. The modes of resonators scaling down to single point defects in the surrounding bulk lattice are characterized via spectral position and multipolar nature of the eigenstates. The mode profiles in real and momentum space are mapped using far‐field imaging and Fourier‐spectropolarimetry, revealing how certain properties of the cavity modes reflect on their origin in the topological bandstructure. This includes band‐inversion‐induced confinement and inverted scaling of mode spectra for trivial and topological defect cavities. Furthermore, hallmarks of topological protection in the loss rates are demonstrated, which are largely unaffected by cavity shape and size. The results constitute an important step toward the use of radiative topological cavities for on‐chip confinement of light, control of emitted wave fronts, and enhancement of light–matter interactions.

Optical properties and thermal stability of the H+-implanted Dy3+/Tm3+-codoped GeS2–Ga2S3–PbI2 chalcohalide glass waveguide

Abstract Optical waveguides play a vital role in the manufacture of various optical devices due to their unique performances and high-degree integration. We report on the preparation and characterization of the planar waveguides in the Dy3+/Tm3+-codoped GeS2–Ga2S3–PbI2 chalcohalide glass. The waveguide was formed by the 400 keV H+-ion implantation with a dose of 8 × 1016 ions/cm2. Its thermal stability was studied by annealing at 260°C for 1 h. The changes in the nuclear energy loss with the implantation depth were simulated by the stopping and range of ions in matter (SRIM 2013). The dark-mode characteristics of the waveguide were measured by the prism coupling method. The refractive index distribution of the optical waveguide was reconstructed by the reflectivity calculation method. The modal profile of the waveguide structure was calculated by the finite-difference beam propagation method (FD-BPM). The thermally stable proton-implanted Dy3+/Tm3+-codoped GeS2–Ga2S3–PbI2 chalcohalide glass waveguide is expected to be applied in mid-infrared integrated optical devices.

On the model-based design and comparison of crystallization-based deracemization techniques

• Novel continuous seeded crystallization process with racemization is designed. • A steady state model is developed based on the thermodynamic features. • With this process, in total four techniques are identified for deracemization. • The qualitative and quantitative comparison of the four processes are carried out. Deracemization techniques produce target enantiomer (eutomer) by converting the undesired enantiomer (distomer) through a racemization reaction. We identify four techniques differing in operation mode and temperature profile. The novel ”MSMPR-type deracemization” process consists of continuous seeded crystallization process coupled with racemization. A steady state model enables us to identify the feasible operating region spanned by feed concentration and residence time, at different racemization kinetics and temperatures. The analysis shows that the most productive operating point corresponds to the least robust operating conditions, thus revealing the trade-off between productivity and purity. Based on this study, which complements and integrates our previous contributions on crystallization-based deracemization, we clarify the characteristic features of each process and compare the four processes in a case study. The results demonstrate that cooling processes outperform temperature cycles techniques in terms of productivity and yield, but the latter provides larger purity if the distomer nucleation cannot be avoided.

Optically active cross-band transition in double-walled carbon nanotube and its impact on Raman resonances

Double-walled carbon nanotubes (DWNTs), often regarded as the simplest one-dimensional (1D) van der Waals moiré superlattices, are the ideal structures to explore the interlayer coupling, including mechanical and electronical coupling, at the nanoscale in 1D systems. By combining spatial modulation spectroscopy (SMS) and resonant Raman scattering (RRS) experiments on well-identified individual free-standing DWNTs with the calculations of their optical absorption by using the recursion method with non-orthogonal tight-binding (NTB) basis functions, we are able to unambiguously assign the nature, namely mirror transition or cross transition, of each optical transitions in DWNTs. Our study identifies and allows to determine the conditions of the mixing of the electronic states leading to the appearance of cross transitions in the optical absorption of DWNTs, beyond of the so-called Koshino's criteria previously derived. On the other hand, the striking behavior of the resonant excitation profile (REP) of the Raman active modes around the cross transition reveals the strong sensitivity of the modes intensity on the electronic interlayer coupling in DWNTs, emphasizing the relevance of Raman spectroscopy for studying the electronic and mechanical coupling at the nanoscale.

A comparative study of MIR and NIR spectral models using ball-milled and sieved soil for the prediction of a range soil physical and chemical parameters

This study evaluated the influence on predicted physical and chemical parameters of soil particle sizes commonly used in the infrared spectra acquisition, < 0.100 mm (ball-milled) and < 2 mm for MIR and NIR ranges, respectively. The influences were evaluated through the accuracy (RMSEP and RPIQ) results and the chemical information extracted by multivariate classification and regression models. For this a national population of soils containing 888 samples from 225 modal soil profiles, each with the reference values of sand, silt, clay, pH(CaCl2), pH(Water), total carbon, organic carbon (OC), cation exchange capacity, nitrogen, aluminium and bulk density, was used. Spectra were collected in MIR and NIR ranges using samples with both particle sizes. For each soil attribute, 29 random calibration and validation sets were generated and SVM, PLS and Cubist regression models were built. This same strategy was used to classify the soil samples according to their respective horizons (1 or 2-7) using SVM, PLS-DA and random forest algorithms. Results obtained by the randomised calibration and validation set did not present positive or negative bias on the RMSEP and RPIQ values based on soil particle sizes. In general, random variations of the RMSEP and RPIQ values were observed for all soil attributes. In addition, ball-milled and < 2 mm spectral models did not present large differences in both accuracy parameters simultaneously. The median Matthews correlation coefficient values calculated by the classification models showed minor variations of 2.61% and 0.65% for samples from both particle sizes in MIR and NIR ranges, respectively. The ‘Variable Importance in Projection’ or VIP scores, calculated by PLS and PLS-DA models, did not show any large variation in the chemical information extracted from MIR and NIR spectra for models built using samples from both particle sizes. The results from this study show that scanning ball-milled or < 2 mm sieved soil samples will result in spectra models in MIR and NIR ranges with the same accuracy and same chemical information. This suggests there is a big potential to eliminate the ball-milling sample step in soil laboratories that use MIR and NIR vibrational spectroscopy techniques to predict soil attributes, thereby reducing the time and costs associated with soil analysis.

Circular Displacement Current Induced Anomalous Magneto‐Optical Effects in High Index Mie Resonators

AbstractDielectric Mie nanoresonators showing strong light–matter interaction at the nanoscale may enable new functionality in photonic devices, such as strong magneto‐optical effects. However, most reports so far have been focused on the enhancement of conventional magneto‐optical effects. Here, anomalous magneto‐optical effects are observed in high‐index‐contrast Si/Ce:YIG/YIG/SiO2 Mie resonators. In particular, giant modulation of light intensity in transverse magnetic configuration up to 6.4% under s‐polarized incidence appears, which is non‐existent in planar magneto‐optical thin films. A large rotation of transmitted light polarization in longitudinal magnetic configuration is also observed, which is two orders of magnitude higher than for planar magneto‐optical thin films. These phenomena are originated from the unique circular displacement current when exciting magnetic resonances in the Mie resonators, which change the electric field direction locally. This work indicates an uncharted territory of light polarization control based on complex modal profiles in all‐dielectric magneto‐optical Mie resonators and metasurfaces.

Research on profile design criteria of 100 m CSG dams

Cemented sand gravel (CSG) dams, as a newly-developing dam type, has attracted great attention in dam construction industry around the world due to its environmental friendliness and economic efficiency. However, there has been no uniform design specification for its construction yet due to insufficient application research. Based on the design theories of concrete dam and earth-rock dam, this paper quantified the impact and control factors of the foundation with reference to the sluice design theory, proposed the structural failure mode and optimal profile of four 100 m CSG dams with different cementing material content under different foundation conditions, and analyzed the profile design criteria of 100 m CSG dams. Results showed that: (1) the failure modes of CSG dams may include overall instable failure along the dam foundation plane, instable failure of dam slope and local stress failure of dam or dam foundation, etc.; (2) if CSG materials were used in rock foundation, the dam body stress should be used as the control criterion; while on extremely soft rock foundation, the control criterion should be based on the amount of CSG materials; (3) if CSG materials were used on rock-soil foundation, bearing capacity and anti-sliding stability of the foundation should be used as the control criterion; while on gravelly soil foundation, the control criterion should be based on the amount of CSG materials. These results may be used as a reference for designers, laying a foundation for the extension and application of CSG dams.

Chiral germanium micro-gears for tuning orbital angular momentum.

Group IV light sources with vertical emission and non-zero orbital-angular momentum (OAM) promise to unlock many novel applications. In this report, we demonstrate cylindrically symmetrical germanium micro-gear cavities, fabricated by etching a grating around the circumference of standard micro-disks, with periods ranging from 14 to 22. Photoluminescence (PL) measurements were done to identify the confined whispering-gallery modes (WGM). Finite-difference time-domain (FDTD) simulations were conducted to map the resonant modes to their modal profiles and characteristics. Vertical emission of WGMs with non-zero OAM was demonstrated, with a clear dependence of the OAM order (ell) on the WGM azimuthal order and the number of micro-gear grating periods. As the chirality, or the direction of rotation, is not controlled in a symmetrical cavity, we propose introducing staircase or triangular-shaped gear periods resulting in an asymmetry. By choosing the diameter, number of periods, and the asymmetrical direction of the gear-teeth, it is possible to generate OAM signals with certain wavelength, OAM order and chirality.

Profile of Twenty-Three Human Milk Oligosaccharides in Han Chinese Mothers throughout Postpartum 1 year

Human milk oligosaccharides (HMOs) are multifunctional carbohydrates in breast milk, which are composed by a variety of structures. This study aimed to identified HMOs concentration profile, milk microbiota composition, and the associations with major maternal characteristics in Han Chinese mothers in the one-year lactation period. Seventeen healthy mothers aged from 28 to 36 years, who gave birth to healthy term infants, were recruited. Carbohydrates were detected using the MIRIS human milk analyzer (HMA), and twenty-three HMOs were quantified using ultra-performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS). Results showed that carbohydrates were relatively stable, while total HMO concentrations ranged from 1.74 to 9.72 g/L and decreased gradually over lactation in breast milk. Based on the structure, seven sialylated HMOs concentration showed the significant decline (p&lt;0.05) after three months in lactation. In addition, the relationships between maternal factors, containing the lactation period, genetic status, delivery mode, parity, and milk microbiota profile, and the HMO composition in healthy women, which still need further investigations, were observed.

Femtosecond laser-inscribed optical waveguides in dielectric crystals: a concise review and recent advances

Femtosecond laser inscription or writing has been recognized as a powerful technique to engineer various materials toward a number of applications. By efficient modification of refractive indices of dielectric crystals, optical waveguides with diverse configurations have been produced by femtosecond laser writing. The waveguiding properties depend not only on the parameters of the laser writing but also on the nature of the crystals. The mode profile tailoring and polarization engineering are realizable by selecting appropriate fabrication conditions. In addition, regardless of the complexity of crystal refractive index changes induced by ultrafast pulses, several three-dimensional geometries have been designed and implemented that are useful for the fabrication of laser-written photonic chips. Some intriguing devices, e.g., waveguide lasers, wavelength converters, and quantum memories, have been made, exhibiting potential for applications in various areas. Our work gives a concise review of the femtosecond laser-inscribed waveguides in dielectric crystals and focuses on the recent advances of this research area, including the fundamentals, fabrication, and selected photonic applications.

The low emission mode in PSR B0329+54

ABSTRACT We investigate properties of the low emission mode in PSR B0329+54 based on four single-pulse observations at frequency centred at 1.54 GHz using Nanshan radio telescope in Urumqi. The low emission mode is characterized by an intensity drop in the central component below that of the other two components. Referred here as the low mode, it has an average duration of 3P0 and is observed in both abnormal and normal emission modes of the pulsar occupying 3.6 per cent of the observed pulses. We demonstrate that the properties of low modes are related to the two modes. We find that the integrated profile of low modes is unique to the two modes, and that low modes occur more frequently when the pulsar is in the normal mode. Analysis of the energy distribution for normal low modes suggests that the cause for the intensity drop in the central component is separated from the emission of the other two components. We demonstrate that the pulse emission characteristics in the normal emission mode shortly after a low-mode bears some similarities with the abnormal mode and gradually recovering to the original normal emission in about three pulsar periods. In addition, the occurrence rate for low modes in different normal modes is mostly consistent, which implies that the duration of low modes is related to a normal mode for this pulsar. Our results imply profile modes each corresponds to specific magnetospheric plama density in particular geometric configuration, and profile mode changing signifies distinct changes of both at different parts of the profile.

Exploiting Plasmonic Phenomena in Polymer Optical Fibers to Realize a Force Sensor.

In this work, a novel sensing approach to realize a force optical fiber sensor is designed, developed, and experimentally tested. The proposed sensing methodology exploits the effects of deformation due to an applied force on a patch of plastic optical fiber (POF) connected at the input of a surface plasmon resonance (SPR) sensor realized in a D-shaped POF. Therefore, the proposed force sensor system consists of an SPR D-shaped POF sensor, connected to a spectrometer, within input of a POF patch, connected to a light source used for interacting with the applied force. When the applied force on the patch changes, the mode profile of the light in the multimode POF patch and the SPR-POF sensor change too, so the SPR spectra shift. The obtained experimental results demonstrate that the proposed sensor has a resolution of the force sensor equal to about 22 mN and an excellent linear response in the range from 0 N to 0.5 N.

Influence of Ga+ milling on the spin waves modes in a Co2MnSi Heusler magnonic crystal

Ferromagnetic resonance experiment was performed to study the magnonic modes of an antidot lattice nanopatterned in a sputtered Co2MnSi Heusler alloy thin film. The magnonic crystal was prepared with a Ga+ focused ion beam, and micromagnetic simulations were used to explain qualitatively and quantitatively the complex experimental spin waves spectrum. We demonstrate the necessity to consider the geometrical imperfections and the modification of the Co2MnSi magnetic parameters induced by the nanofabrication process to describe the evolution of the frequencies and spatial profiles of the principal experimental spin waves modes in the 0–300 mT magnetic field range. In particular, our model suggests that Ga+ milling induces a drastic decrease (between 80% and 90%) in the bulk Co2MnSi magnetic parameters. In addition, simulations reveal the presence of a diversity of localized and extended spin waves modes whose spatial profiles are closely related to the evolution of the magnetic state at equilibrium from a very non-collinear configuration up to a quasi-saturated state.

Resonance modes of periodically structuralized microwave magnetic elements

Here we consider a flower-like structure of a resonator consisting of six elliptical elements, referred to as petals, made from a magnetic material. The petals are positioned with their centres at the corners of a regular hexagon. Using numerical simulations (CST Studio) we examine the effect of different radial orientations of petals. We study resonance modes with a specific distribution of the electromagnetic field within the resonator as well as the effect of the rotation of petals on the field distribution. The mode character is crucial to understand the behaviour of the frequency spectrum. E.g., the rotation of petals influences significantly the frequency of the lowest mode only, while the other frequencies are almost unchanged and this effect is directly related to the profiles of modes. The system studied is a promising candidate for a tuneable component of an integrated detection system.

Femtosecond laser micromachining of suspended silica-core liquid-cladding waveguides inside a microfluidic channel

This work addresses the fabrication of straight silica-core liquid-cladding suspended waveguides inside a microfluidic channel through fs-laser micromachining. These structures enable the reconfiguration of the waveguide's mode profile and enhance the evanescent interaction between light and analyte. Further, their geometry resembles a tapered optical fiber with the added advantage of being monolithically integrated within a microfluidic platform. The fabrication process includes an additional post-processing thermal treatment responsible for smoothening the waveguide surface and reshaping it into a circular cross-section. Suspended waveguides with a minimum core diameter of 3.8 µm were fabricated. Their insertion losses can be tuned and are mainly affected by mode mismatch between the coupling and suspended waveguides. The transmission spectrum was studied and it was numerically confirmed that it consists of interference between the guided LP01 mode and uncoupled light and of modal interference between the LP01 and LP02 modes.

Vision-based vibration mode shape extraction for identifying cracks in a cantilever beam

Abstract Taking significant merits of high spatial resolution of image sensing, the vibration mode shape of a cantilever beam (CB) is obtained from the free vibration process for local crack identification and structural health monitoring. This vision-based vibration measurement uses a cost-effective rolling shutter camera and a computationally efficient singular value decomposition (SVD). It shows that vibration modes of a continuous structure such as a CB are mainly determined by spatial resolution and less rely on temporal resolution. Moreover, images recorded by the camera maintain the critical information about mode profiles though distortions are introduced into the image. Decomposing the images by SVD allows the vibration modes to be extracted with good degree of accuracy. Both simulation study and experimental verification shows that this novel approach allows different sizes of cracks and locations to be identified.

Gyrotropy-governed isofrequency surfaces and photonic spin in gyromagnetic media

Topology of isofrequency surfaces plays a crucial role in characterizing the interaction of an electromagnetic wave with a medium. Thus, engineering the topology in complex media is leading to novel applications, ranging from super-resolution microscopy with hyperbolic metamaterials to sub-wavelength waveguiding structures. Here, we investigate the spin-governed nature of isofrequency surfaces in a general gyromagnetic medium. We show that gyrotropy also plays an important role in the topological properties of a medium, along with the anisotropic permeability and permittivity. Even though the topology primarily depends on permeability, gyrotropy can suppress or support the existence of certain topological surfaces. We reveal the connection between the gyrotropy imposed constraints and the photonic spin-profile of the topological surfaces. The spin-profile along the isofrequency surface is locked to the material, resulting in the non-reciprocity and breaking of the spin-momentum locking in the gyromagnetic medium. Further, we show that the conflict between spin-momentum locking and material locked spin leads to asymmetric mode profile and gyrotropy-induced cutoff in guided wave structures. Our work provides important insights into the underlying link between topology, spin, and non-reciprocity in gyrotropic media.