Torsional Rotation Research Articles

Body Mass Index is Related to Femoral Anteversion, Hip Rotation During Gait, and Passive Hip Range of Motion in Children and Adolescents.

Overweight and obesity are major global health issues, often linked to orthopaedic problems, skeletal malalignments, and altered gait biomechanics. However, skeletal and biomechanical adaptions in the transverse plane remain underexplored. Therefore, this study aimed to investigate the relationship between body mass index (BMI) and variables describing lower extremity torsional profiles, hip rotation mobility, and transverse plane gait characteristics in children and adolescents. Acetabular and femoral anteversion, tibial torsion (measured through computed tomography), hip and knee rotation, and foot progression angles during the stance phase of gait (measured by 3D gait analysis), as well as passive hip rotation range of motion (evaluated as the midpoint of hip rotation in clinical examination), were retrospectively analyzed in 122 children and adolescents. Correlations between all variables and logit-transformed BMI percentiles were calculated. Moderate correlations were found between BMI percentile and hip rotation during the stance phase (r=-0.68, P<0.001), the passive midpoint of hip rotation (r=-0.51, P<0.001), and femoral anteversion (r=-0.50, P<0.001). Small correlations were observed for acetabular anteversion (r=-0.36, P<0.001), knee rotation during stance phase (r=0.34, P<0.001), and foot progression angle during stance phase (r=-0.31, P<0.001). Tibial torsion showed a nonsignificant negligible relationship with BMI percentile (r=-0.26, P=0.004). BMI percentile was positively correlated with external hip rotation during the stance phase of gait and passive external hip rotation, and negatively correlated with femoral anteversion. These findings suggest abnormal body weight is associated with static and dynamic biomechanical alterations. Therefore, weight management should be considered in orthopaedic assessments and treatment planning for children and adolescents.

Influence of Intermolecular Interactions on the Photophysical Properties of Carbazolyl Phosphorescent Molecules

AbstractThe photophysical properties of three carbazolyl phosphorescent molecules with similar structures‐5‐(9H‐carbazole‐9‐group) nicotinitrile (P35N), 5‐(9H‐carbazole‐9‐group) nicotinamide (P35M) and 2‐(9H‐carbazole‐9‐group) isonicotinamide (P25M)‐are investigated theoretically. The influence on luminescence is primarily elucidated through an analysis of geometry, electronic structure, and the dynamic processes occurring within the excited state. Structural analysis indicates that P35M exhibits the most effective luminescence due to minimal structural changes, reduced separation between the electron and hole, and enhanced intermolecular interactions within the crystal. Excited state dynamics and recombination energy analysis indicate that the higher triplet exciton population in the P35M molecule contributes to its long‐lived phosphorescence. Furthermore, the intersystem crossing process for the three molecules is predominantly governed by low‐frequency torsional rotation, while bond stretching vibrations are the primary factor leading to the inactivation of non‐radiative processes. The distinct vibrational channels associated with reverse intersystem crossing and non‐radiative processes present opportunities for further enhancement of the phosphorescent characteristics of these molecules.

Accurate Calculation of Interatomic Forces with Neural Networks Based on a Generative Transformer Architecture.

Using neural networks to express electronic wave functions represents a new paradigm for solving the Schrödinger equation in quantum chemistry. For practical quantum chemistry simulations, one needs to know not only energies of molecules, but also accurate forces acting on constituent atoms. In this work, we achieve the accurate calculation of interatomic forces on QiankunNet, a platform that combines transformer-based deep neural networks with efficient batched autoregressive sampling. Our approach permits the application of the Hellmann-Feynman theorem to force calculations without introducing corrective Pulay terms. The results show that the calculated interatomic forces are in close agreement with those derived from the full configuration interaction method, irrespective of whether the system is a simple molecule or a strongly correlated electron system like a linear hydrogen chain. Furthermore, the calculated interatomic forces are employed for atomic relaxation in the torsional rotation process of ethylene, and the energy barrier obtained from the scanned potential energy surface is in excellent agreement with the experiment. Our work contributes to the application of artificial intelligence to broader quantum chemistry simulations, such as modeling challenging chemical transformations where electron correlations are difficult to describe.

A Jacobi-Ritz Approach for Aeroelastic Analysis of Swept Distributed Propulsion Aircraft Wing

Abstract This paper presents a Jacobi-Ritz approach for conducting flutter and divergence analysis of a complex distributed propulsion aircraft wing like NASA X-57. The general orthogonal Jacobi polynomials are used to approximate the bending displacement and torsional rotation angle in the Ritz method based structural and aeroelastic analysis. The Jacobi polynomials satisfy the orthogonality condition using weight functions which are easily modified to satisfy different essential and natural boundary conditions. Compared to simple polynomials, Jacobi polynomials can eliminate the well-known ill-conditioning numerical issues when considering higher-order polynomials. The Jacobi-Ritz method is also found to alleviate mode switching often encountered in tracking the changes of modes with the varying airspeed. The Jacobi-Ritz method is later used to investigate the flutter and divergence speeds under distributed propulsor mass and their locations, nonuniform aerodynamic model in the presence of multiple propulsors, and the sweep angle. Results show that placing the distributed propulsors on the wing's leading edge increases the flutter speed even though the bending and torsion modal frequencies are decreased compared to those of the wing without propulsors. The presence of pods for the middle high-lift motors causes an extra aerodynamic moment which reduces the flutter speed. Parametric studies also show that the divergence speed is lower than the flutter speed for a uniform and straight distributed propulsor wing. Using swept-back wing configuration and placing the tip propulsor near the wing's leading edge can help to increase both flutter and divergence speeds.

Is The Dorsal Dartos Flap Rotation Technique Successful in Children with Isolated Penile Torsion?

Penile torsion is a counterclockwise rotational anomaly of the penile shaft or glans. We aimed to evaluate the results of dorsal dartos flap rotation technique in children with isolated penile torsion. 5470 boys who applied to our clinic between 2012 and 2022 for circumcision were evaluated for congenital isolated penile torsion. They were classified according to the degree and direction of torsion and clinical findings were analyzed. According to the degree of torsion, penile degloving or dorsal dartos flap rotation technique with circumcision was performed. Patients whose torsion corrected after penile degloving were excluded from the study. The results of dorsal dartos flap rotation technique were evaluated. Results: Congenital isolated penile torsion ≥60° was identified in 1.04 % (n=57) of the children. Eight patients whose torsion corrected after penile degloving were excluded from the study. 49 patients who underwent dorsal dartos flap rotation had a mean age of 4.94 years (1-9) and a mean operation time of 29.9 min (20-40). The mean degree of torsion was 77.6° (60-110). The mean operation times in the < 90° and ≥ 90° dorsal dartos flap groups were statistically significant (p<0.05). Residual torsion was statistically significant in the < 90° and ≥ 90° dorsal dartos flap groups (p<0.05). At the postoperative 1st and 6th month follow-ups, torsion less than 10 degrees was observed in 3 patients who underwent dorsal dartos flap rotation technique. No residual torsion was observed in other patients. Isolated penile torsion cases should not be overlooked during circumcision. It seems possible to obtain successful results with dorsal dartos flap rotation in moderate and severe torsions.

Westerfit: A new program for spin–torsion–rotation spectra

A new program, westerfit, has been developed to treat Cs molecules with internal rotation and spin angular momentum. It implements a single diagonalization Rho Axis Method approach for the torsion–rotation alongside a complete treatment of nuclear quadrupole interaction and spin–rotation coupling. Unlike other programs designed for internal rotation with spin effects, westerfit includes matrix elements off-diagonal in the rotational angular momentum quantum number, N, rather than the perturbative treatment of the spin–rotation and quadrupole interactions. This full combined approach allows fitting of all symmetrically allowed terms in both the spin–rotation and the quadrupole tensors as well as inclusion of higher order terms coupling the large amplitude motion to the spin angular momentum. The program was benchmarked against other published programs to test molecular cases of torsion–rotation, spin–rotation, and spin–torsion-rotation. All three tests produced a lower RMS. westerfit paves a way forward for complete treatment of spin–torsion–rotation problems regardless of barrier height or quadrupole moment.

Ultrafast Hot Exciton Nonadiabatic Excited-State Dynamics in Green Fluorescent Protein Chromophore Analogue.

The ultrafast high-energy nonadiabatic excited-state dynamics of the benzylidenedimethylimidazolinone chromophore dimer has been investigated using an electronic structure method coupled with on-the-fly quantitative wave function analysis to gain insight into the photophysics of hot excitons in biological systems. The dynamical simulation provides a rationalization of the behavior of the exciton in a dimer after the photoabsorption of light to higher-energy states. The results suggest that hot exciton localization within the manifold of excited states is caused by the hindrance of torsional rotation due to imidazolinone (I) or phenolate (P) bonds i.e., ΦI- or ΦP-dihedral rotation, in the monomeric units of a dimer. This hindrance arises due to weak π-π stacking interaction in the dimer, resulting in an energetically uphill excited-state barrier for ΦI- and ΦP-twisted rotation, impeding the isomerization process in the chromophore. Thus, this study highlights the potential impact of the weak π-π interaction in regulating the photodynamics of the green fluorescent protein chromophore derivatives.

Humeral Torsion in Relation to Shoulder Range of Motion in Elite Field Hockey Players.

Sport-specific adaptations in shoulder rotation range of motion (ROM) and the relationship with humeral torsion have been described in overhead-throwing sports. However, information is lacking for other shoulder-loading sports such as field hockey. Therefore, this study's purpose was to evaluate humeral torsion in elite, male field hockey players and explore its association with shoulder ROM. Cross-sectional study. Twenty-five male, elite field hockey players were included. Humeral torsion and shoulder external and internal rotation ROM were evaluated bilaterally by ultrasound and an inclinometer smartphone application, respectively. Field hockey players showed a significantly increased humeral retroversion on the dominant compared with the nondominant side (P < .001; Cohen d = 1.75), along with a significantly increased external (P = .004; Cohen d = -0.64) and decreased internal rotation ROM (P = .003; Cohen d = 0.65). This finding illustrates a shift in total shoulder rotational ROM arc. Correlation analysis showed a significant moderate association between the increased humeral retroversion and decreased internal rotation ROM on the dominant side (r = .523). Elite male field hockey athletes show sport-specific adaptations regarding humeral torsion and shoulder rotation ROM, similar to throwing athletes. These findings increase our insight into the field hockey athlete's shoulder, which is essential to optimize performance and assist in correctly interpreting shoulder rotational ROM measurements.

Axial compressive performance of cruciform timber-encased steel composite columns: Experimental investigation and buckling analysis through 3D laser scanning

Timber-encased steel composite (TESC) columns have garnered increasing attention owing to their high mechanical performance. However, limited studies have focused on the compressive performance of cruciform TESC columns and accurate evaluations of the full-field deformation of embedded steel components. In this paper, a novel cruciform TESC column embedded with a thin-walled cruciform steel component was proposed. 22 specimens including TESC columns, bare steel columns and bare glulam columns were tested under axial compression. Parameters such as the width and thickness of the cruciform steel component were considered. 3D laser scanning technologies were applied to measure the full-field deformation of 20 steel members, thus quantitatively assessing the reduction in the deformation of steel components resulting from the lateral restraint of timber. Finally, a nonlinear fitting equation was established to predict the load-carrying capacity. The results showed that the TESC columns exhibited significant enhancements in stiffness and load-carrying capacity. The lateral restraint of timber caused the buckling modes of the steel to change from torsional buckling to mainly local buckling. Moreover, the high post-yield stiffness of the steel components before reaching the maximum load indicated that the timber offered sufficient lateral restraint to make full use of the steel strength. The 3D laser scanning method accurately measured the full-field deformation of the steel at the failure state. Compared to bare steel columns, the torsional rotation of the steel components decreased by up to 83.14 %, while the maximum absolute lateral deflection decreased by up to 80.89 %. The suggested strength formula offered sufficient accuracy in predicting the load-carrying capacity of short TESC columns, with ratios between the calculated and experimental values ranging from 0.908 to 1.120.

On torsion of FG elastic nanobeams on nonlocal foundations

A plethora of challenging nanomechanical applications deals with ultrasmall composite structures interacting with nonlocal media. To capture size dependent behaviors, effective tools of Nonlocal Continuum Mechanics can be conveniently adopted, provided that the relevant structural problem is well-posed. A crucial improvement in modeling of nanobeams on nanofoundations is provided in the present work with respect to the formulation based on the Eringen–Wieghardt nonlocal approach. Scale effects on FG nanobeams under torsion are effectively captured by exploiting the consistent stress-driven integral theory of elasticity. A novel formulation of size dependent elastic foundations is here introduced. Notably, the constitutive behavior describing interaction between twisted nanobeams and surrounding media is modeled by spatial convolution driven by the torsional rotation field. It is shown that the governing structural problem is mathematically represented by an integro-differential formulation. An equivalent simpler differential problem is then proven to reduce computational burdens. Exemplar case-studies are finally examined to show efficacy of the developed nonlocal methodology.

3D Slicer open-source software plug-in for vector-based angle calculation of canine hind limb alignment in computed tomographic images.

Severe and complex angular limb deformities in dogs require accurate morphological assessment using diagnostic imaging to achieve successful orthopedic surgery. Computed tomography (CT) is commonly used to overcome projection errors in two-dimensional angular measurements of dog hindlimb alignment. Three-dimensional volume rendering (VR) techniques permit virtual positioning and variable projection, but the final CT-image that defines the projection plane for angular measurements remains two-dimensional. We wanted to develop a true three-dimensional open-source technique to measure the alignments of the hind limbs of dogs in CT scanners. We developed an open-source 3D Slicer plug-in, to perform angular measurements using vector calculations in three-dimensional space. In 113 CT-scans of canine pelvic limbs, femoral torsion, femoral varus, femorotibial rotation, tibial torsion, tibial varus and tibiotalar rotation angles were calculated and compared to an already validated technique using VoXim®. Reference points were identified and measurements were possible in the 113 acquisitions. The greatest difference between the two techniques was 1.4° at only one tibial torsion angle. Mean values for all Bland-Altman plots did not show significant differences and were less than 0.07° for all comparisons. Based on these results we considered angular measurements of canine hind limb alignment in CT scans using the 3D Slicer extension program sufficiently accurate for clinical orthopedic and surgical purposes in veterinary medicine. With our open-source 3D Slicer extension software, we provide a free accessible tool for veterinary orthopedic surgeons and thus we hope to improve angular measurements in CT-scans of canine hind limb deformities through true three-dimensionality.

Zigzag optical cavity for sensing and controlling torsional motion

Precision sensing and manipulation of milligram-scale mechanical oscillators has attracted growing interest in the fields of table-top explorations of gravity and tests of quantum mechanics at macroscopic scales. Torsional oscillators present an opportunity in this regard due to their remarked isolation from environmental noise. For torsional motion, an effective employment of optical cavities to enhance optomechanical interactions—as already established for linear oscillators—so far faced certain challenges. Here, we propose a concept for sensing and manipulating torsional motion, where exclusively the torsional rotations of a pendulum are mapped onto the path length of a single two-mirror optical cavity. The concept inherently alleviates many limitations of previous approaches. A proof-of-principle experiment is conducted with a rigidly controlled pendulum to explore the sensing aspects of the concept and to identify practical limitations in a potential state-of-the art setup. Based on this study, we anticipate development of precision torque sensors utilizing torsional pendulums that can support sensitivities below 10−19Nm/Hz, while the motion of the pendulums are dominated by quantum radiation pressure noise at sub-microwatts of incoming laser power. These developments will provide horizons for experiments at the interface of quantum mechanics and gravity. Published by the American Physical Society 2024

Impact of atropisomerism on a non-steroidal glucocorticoid receptor agonist.

To investigate atropisomers of non-steroidal glucocorticoid receptor modulator GSK866, a virtual library of substituted benzoic acid analogues was enumerated. Compounds from this library were subjected to a torsion angle scan using Spartan'20 to calculate the torsion rotation energy barrier which identified compounds predicted to be stable as atropisomers. After synthesis of the library, analysis showed that compounds 13 and 14 existed as stable atropisomers 13a, 13b, 14a and 14b, in agreement with the earlier calculations. Screening in a glucocorticoid receptor cellular assay showed that one compound from each atropisomer pair was significantly more potent than the other. Docking in a public structure of the glucocorticoid receptor (PBD code 3E7C) enabled the stereochemistry of the two most potent compounds 13a and 14b to be assigned as (R a) and (S a), respectively.

Distinguishing Protein Chemical Topologies Using Supercharging Ion Mobility Spectrometry-Mass Spectrometry.

A technique combining ion mobility spectrometry-mass spectrometry (IMS-MS) and supercharging electrospray ionization (ESI) has been demonstrated to differentiate protein chemical topology effectively. Incorporating as many charges as possible into proteins via supercharging ESI allows the protein chains to be largely unfolded and stretched, revealing their hidden chemical topology. Different chemical topologies result in differing geometrical sizes of the unfolded proteins due to constraints in torsional rotations in cyclic domains. By introducing new topological indices, such as the chain-length-normalized collision cross-section (CCS) and the maximum charge state (zM ) in the extensively unfolded state, we were able to successfully differentiate various protein chemical topologies, including linear chains, ring-containing topologies (lasso, tadpole, multicyclics, etc.), and mechanically interlocked rings, like catenanes.

Distinguishing Protein Chemical Topologies Using Supercharging Ion Mobility Spectrometry‐Mass Spectrometry

AbstractA technique combining ion mobility spectrometry‐mass spectrometry (IMS‐MS) and supercharging electrospray ionization (ESI) has been demonstrated to differentiate protein chemical topology effectively. Incorporating as many charges as possible into proteins via supercharging ESI allows the protein chains to be largely unfolded and stretched, revealing their hidden chemical topology. Different chemical topologies result in differing geometrical sizes of the unfolded proteins due to constraints in torsional rotations in cyclic domains. By introducing new topological indices, such as the chain‐length‐normalized collision cross‐section (CCS) and the maximum charge state (zM) in the extensively unfolded state, we were able to successfully differentiate various protein chemical topologies, including linear chains, ring‐containing topologies (lasso, tadpole, multicyclics, etc.), and mechanically interlocked rings, like catenanes.

A technique for modeling and optimizing the design of wave energy conversion devices

With the continuous development of society and the economy, energy shortages have become increasingly prominent. As an important marine renewable energy source, wave energy holds significant theoretical significance due to its widespread distribution and vast storage potential. In this paper, we employ differential equation theory, numerical optimization methods, and optimization techniques to model and design algorithms for investigating the energy conversion mechanisms of wave energy devices. Due to the complex situation, we decided to simplify that into two scenarios. As to the first scenario, the essence of energy output in wave energy devices lies in the relative velocity between the floater and the oscillator. Firstly, the product of the damping force and the instantaneous relative velocity is integrated over time and divided by the period to obtain the average output power. Maximizing the average output power, with the damping coefficient as the decision variable, establishes a nonlinear optimization model. Secondly, a stepwise optimization approach is applied to control the damping coefficient, resulting in optimal damping coefficients of 33600, . Finally, a genetic algorithm is employed to validate the results as to the next scenario. After adding rotational dampers and torsion springs to the wave energy device, the relative velocity and relative angular velocity between the floater and the oscillator jointly contribute to energy output. The objective is to maximize the sum of the average output power of linear dampers and rotational dampers. The decision variables are the linear damping coefficient and the rotational damping coefficient. A nonlinear optimization model is established. A stepwise optimization approach is applied to optimize both types of coefficients, and the results are validated using a genetic algorithm. The optimal solution is found to have a linear damping coefficient of 60135.7781 N·s/m and a rotational damping coefficient of 4244.90358 N·s·m for the rotational dampers.

Biomechanical evaluation of different posterior fixation techniques for treating thoracolumbar burst fractures of osteoporosis old patients: a finite element analysis.

Objective: To investigate the biomechanical characteristics of different posterior fixation techniques in treatment of osteoporotic thoracolumbar burst fractures by finite element analysis. Methods: The Dicom format images of T10-L5 segments were obtained from CT scanning of a volunteer, and transferred to the Geomagic Studio software, which was used to build digital models. L1 osteoporotic burst fracture and different posterior fixation techniques were simulated by SolidWorks software. The data of ROM, the maximum displacement of fixed segment, ROM of fractured L1 vertebrae, the stress on the screws and rods as well as on fractured L1 vertebrae under different movement conditions were collected and analysed by finite element analysis. Results: Among the four groups, the largest ROM of fixed segment, the maximum displacement of fixed segment and ROM of fractured vertebrae occurred in CBT, and the corresponding data was 1.3°, 2.57mm and 1.37°, respectively. While the smallest ROM of fixed segment, the maximum displacement of fixed segment and ROM of fractured vertebrae was found in LSPS, and the corresponding data was 0.92°, 2.46mm and 0.89°, respectively. The largest stress of screws was 390.97Mpa, appeared in CBT, and the largest stress of rods was 84.68MPa, appeared in LSPS. The stress concentrated at the junction area between the root screws and rods. The maximum stress on fractured vertebrae was 93.25MPa, appeared in CBT and the minimum stress was 56.68MPa, appeared in CAPS. And the stress of fractured vertebrae concentrated in the middle and posterior column of the fixed segment, especially in the posterior edge of the superior endplate. Conclusion: In this study, long-segment posterior fixation (LSPF) provided with the greatest stability of fixed segment after fixation, while cortical bone screw fixation (CBT) provided with the smallest stability. Cement-augmented pedicle screw-rod fixation (CAPS) and combined using cortical bone screw and pedicle screw fixation (CBT-PS) provided with the moderate stability. CBT-PS exhibited superiority in resistance of rotational torsion for using multiple connecting rods. CAPS and CBT-PS maybe biomechanically superior options for the surgical treatment of burst TL fractures in osteoporotic patients.

Experimental investigation of rotational behavior of pseudo-ductile adhesive angle joints exhibiting variable strain rate

Pseudo-ductile behavior in composite structural frames can be achieved by enabling their beam-column joints to exhibit nonlinear structural response due to progressive damage, by using pseudo-ductile adhesives. This study investigates the static behavior of a novel pseudo-ductile bonded-bolted angle joint with a bolt at the geometric centroid of the joint. A pseudo-ductile elastomer adhesive is used which is notably sensitive to the strain rate. The bolt ensures structural integrity and produces pure torsional moments in the adhesive planes. This configuration induces nonuniform strain rates in the adhesive layers in the radial direction, i.e., from the center outwards. The experimental results reveal that under the nonuniform shear strain distribution, the initial stiffness, yield rotation, and maximum torsion exhibit an increasing trend with strain rate, while maximum rotation decreases. An analytical model was developed using stress-strain relations obtained from single-lap joints with uniform stress distribution to predict the angle joint responses. The analytical model overestimates the initial joint stiffness due to the nonuniform stress distribution but shows good agreement for strength and post-yield behavior. Lastly, the angle joint exhibits the lowest ductility ratios compared to linear lap joints, showing that the pseudo-ductile adhesive capacity may not be fully utilized in the angle configuration.

OA4‐AM23‐ST‐10 | Viscoelastic Testing is Paradoxically Confounded by Hematocrit in Clinical Samples Tested on Both Rotational Torsion and Harmonic Resonance Platforms

OA4‐AM23‐ST‐10 | Viscoelastic Testing is Paradoxically Confounded by Hematocrit in Clinical Samples Tested on Both Rotational Torsion and Harmonic Resonance Platforms

Theoretical studies on the photo protective mechanism of curcuminoids

In this work, the deactivation pathways of curcuminoids after photoexcitation was studied by employing density functional theory to explore their UVA radiation screening capacity. A comprehensive computational characterization of the excited-state processes of curcumin, demethoxycurcumin, and bis-demethoxycurcumin was done. The molecules exist in diketo and enol forms which are in equilibrium and interconvertible through keto-enol tautomerism. The enolic forms of each of the studied molecules have eight geometric cis–trans isomers as a result of torsion rotation about three different carbon–carbon double bonds across the aliphatic chain. For each geometric isomer, sixteen possible rotamers are found to exist due to rotation about five different carbon–carbon single bond rotations, also across the skeleton of the aliphatic chain. Upon photoexcitation, the studied molecules follow three main pathways of radiationless decay: (a) rotamerism and interconversion between rotamers of comparable energies which are in equilibrium, (b) interconversion between the cis–trans geometrical isomers where an efficient vibrational relaxation path is formed at ∼90° during torsion rotation about carbon–carbon double bond, and (c) excited state intramolecular proton transfer in a single O–H stretching vibration through a cyclic intramolecular hydrogen bonded ring formed at the centre of the molecule giving back the original structure. The absorption and emission spectra of the molecules were also simulated where the theoretically obtained absorption and emission maxima are close to the reported experimental values.