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The spatial rigidity and strength of precast multi-story buildings are largely determined by the rigidity of the shear bonds connecting the vertical load-bearing reinforced concrete structures. When a horizontal load is applied in asymmetrical in-plan load-bearing systems of multi-story buildings, torsion occurs. In vertical shear bonds, especially those located furthest from the center of rigidity, a torque appears. This article presents the results of experimental studies of welded joints of precast buildings under the action of shear and torsion. The research study has been conducted using full-scale samples of shear bonds. The samples have been loaded with a static load vertical shear force and horizontal torsion moment. Various loading conditions are considered. Deformation diagrams of shear bonds were obtained. The limit state of a welded joint under shear and shear with torsion is described. The obtained experimental data on the rigidity of shear connections can be used in mathematical models for determining the stress-strain state of load-bearing systems of panel multi-story buildings.

Wandering spleen is a rare condition in children that is often caused by the loss or weakening of the splenic ligaments. Its clinical presentation is variable; 64% of children with wandering spleen have splenic torsion as a complication. A 13-year-old boy who had been showing abdominal pain in the hypogastric region accompanied by vomit and an enormous tumefaction in the suprapubic region came to our observation. Considering the ovoid morphology at ultrasound exam, the echostructure and the marked reduction of parenchymal vascularization, suspicion for torsion of an ectopic spleen arose. Ultrasound evaluation has a primary role in the diagnosis of a suspected wandering spleen and, to avoid potentially life-threatening complications, immediate surgery is often times required.

In this paper, we study the dynamical stability analysis by considering the torsion field ϕ which is proportional to the Hubble parameter and barotropic equation-of-state parameter in the framework of the homogenous and isotropic FLRW metric with non-zero torsion in the scenario of dark matter and dark energy interacting terms. We discuss the stability of the critical points corresponding to the eigenvalues in the presence of dust and radiation at quintessence, ΛCDM and phantom regimes by utilizing the different linear and nonlinear interaction models which depend on the energy density. As a result, we observe that the first linear model shows the stable behavior throughout the universe for dust and radiation phase. The other linear and nonlinear models show the stable critical points, computing with the eigenvalues at phantom and ΛCDM era with the best fit value of interaction strength and coupling constant for dust and radiation. [ABSTRACT FROM AUTHOR]

In recent decades, there has been significant research on the role of torsion in gravity, with a focus on aligning gravity with its gauge formulation and including spin into a geometric description. In order to account for the present phenomenon of the universe’s accelerated expansion, recent developments have introduced f(T) theories that rely on the disparities found in teleparallel gravity. Torsion, rather than curvature, is the fundamental geometric property that describes gravity in these theories. When compared to theories involving f(R) functions, the field equations are consistently of second order and surprisingly simple. We consider a specific type of function called torsion, which is defined as f(T) = T − αT0[{1 + ( T T0 )2}−n − 1]. The expression consists of two free parameters, n and α, and the current value of the torsion scalar, T0. In order to solve the modified torsion field equations (MTFEs), we can utilize the parametrization of the deceleration parameter (DP) in terms of redshift, denoted as q(z) = q0 + q1(z). Here, q0 and q1 represent the model parameters. The model parameters are determined by utilizing observable constraints, including as 57 Hubble data points, 1048 Pantheon supernovae type Ia data, and Baryon Acoustic Oscillations (BAO) datasets. In addition, we utilize Markov Chain Monte Carlo (MCMC) methods for statistical analysis. [ABSTRACT FROM AUTHOR]

The purpose of this study was to understand the dynamic behaviors of lignin-amended loess. Dynamic properties tests of lignin-amended loess with different contents and strength tests at optimum content were carried out by using a hollow cylinder torsion shear apparatus. Firstly, the effect of lignin fiber content (0%, 0.5%, 1%, 2%, 3% and 4%) on the dynamic properties of improved loess was investigated, and the results showed that the optimal lignin content for improved loess was 1%, at which time compared with pure loess the highest increase of the dynamic shear stress in the skeleton curve of the soil was 73.8%, the increase of dynamic shear modulus was 26%, and the decrease of dynamic damping ratio was 60%; Then, the effects of moisture content (12%, 17%, 21%) and consolidated confining pressure (100 kPa, 200 kPa, 300 kPa) on the dynamic strength of 1% modified loess were studied, and the subsidence characteristics of the improved loess were also focused on, the results indicated that the dynamic strength of the improved loess decreased with the increase of moisture content and increase with the confining pressure, and the seismic characteristics increase with the increase of dynamic shear stress and the number of cycles. [ABSTRACT FROM AUTHOR]

The present study explored the presence of torsional gaze-stabilization to proprioceptive neck activation in humans. Thirteen healthy subjects (6 female, mean age 25) were exposed to passive body rotations while maintaining a head-fixed, gravitationally upright, position. Participants were seated in a mechanical sled, their heads placed in a chin rest embedded in a wooden beam while wearing an eye tracker attached to the beam using strong rubber bands to ensure head stability. The body was passively rotated underneath the head both in darkness and while viewing a projected visual scene. Static torsional gaze positions were compared between the baseline position prior to the stimulation, and immediately after the final body tilt had been reached. Results showed that passive neck flexion produced ocular torsion when combined with a visual background. The eyes exhibited rotations in the opposite direction of the neck's extension, matching a hypothetical head tilt in the same direction as the sled. This corresponded with a predicted head rotation aimed at straightening the head in relation to the body. No such response was seen during trials in darkness. Altogether, these findings suggest that proprioception may produce a predictive gaze-stabilizing response in humans. [ABSTRACT FROM AUTHOR]

In this paper, we use the cosmographic approach to discuss Friedmann space-time in the presence of torsion. For this, we explore equations of motion that explain creation in an isotropic and homogeneous cosmic backdrop with nonzero torsion. Here, we consider the energy density of holographic dark energy model ρd = 3c2(z)M p2L−2 where c2 is a dimensionless parameter depending on redshift parameter z,Mp = 1 κ is the reduced Planck mass and L represents the holographic length scale. We examine this dark energy model with both constant and variable holographic length scales in terms of Hubble parameter to determine the best-fit scale. The interaction between dark sector components is taken to evaluate cosmographic parameters, like Hubble, equation of state, deceleration, jerk, snap, lerk and statefinder parameters. We consider four c(z) parametrizations, which are Chevallier–Polarski–Linder, Jassal–Bagla–Padmanabhan, Wetterich and Ma–Zhang for both cases. We obtain consistent results for specific choices of constant parameters in the underlying scenario. [ABSTRACT FROM AUTHOR]

Multi-principal element alloys demonstrate high strength, thermal stability, and irradiation resistance, making them excellent candidate materials for applications in nuclear reactors and other harsh environments. Some studies have examined the use of high-pressure torsion to strengthen MPEAs through grain size reduction and strain hardening. However, no studies have investigated the effect of HPT on secondary phases (precipitates) within an MPEA. Two alloys, (Fe0.3Ni0.3Mn0.3Cr0.1)94Ti2Al4 containing Ni(Ti, Al) B2 phase, and CrFe σ phase, and single-phase Fe0.3Ni0.3Mn0.3Cr0.1, were fabricated by casting and heat treatment. Both alloys were then processed with HPT to study microstructural evolution. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the alloys before and after HPT processing. HPT processing produced a nanocrystalline structure in both alloys, but (Fe0.3Ni0.3Mn0.3Cr0.1)94Ti2Al4 exhibited a significantly smaller grain size and higher dislocation density than Fe0.3Ni0.3Mn0.3Cr0.1, with corresponding higher hardness. Before HPT, the (Fe0.3Ni0.3Mn0.3Cr0.1)94Ti2Al4 alloy consisted of large grain (~ 400 μm) and precipitates, including B2 of ~ 38 μm average size, B2 of ~ 0.7 μm average size, and small amounts of σ of ~ 1.5 µm average size. After HPT, the larger B2 precipitates were decreased in size and volume fraction, while the smaller B2 precipitates were completely dissolved; the σ precipitates appeared unaffected by HPT, likely due to their much higher hardness. Observation of the B2 precipitate distribution along radial distance indicates that the strain caused the precipitates to fracture at intermediate strain (γ = 125) and dissolve at high strain (γ = 280). [ABSTRACT FROM AUTHOR]

We construct mathematical models of the dynamic interaction of a thin piezoceramic inclusion of variable thickness with an elastic isotropic medium under the conditions of axisymmetric torsion of the composite. The conditions of perfect mechanical contact are satisfied on the interface. We consider the case of an electrically insulated and grounded piezoceramic inclusion. Modeling is carried out with the help of the singular perturbation theory. [ABSTRACT FROM AUTHOR]

Advanced splenic flexure tumors are uncommon and have a higher risk of relapse. To ensure that the resection includes the entire area of lymphatic drainage with a complete mesocolic excision (CME), a left extended colectomy is needed. In peritoneal carcinomatosis, there is often extensive involvement of the sigma and splenic flexure of the colon. In many instances, total colectomies are chosen for these patients, even when a significant portion of the colon could be preserved. The potential impact on quality of life after splenic flexure colon resection is discussed, as well as the importance of anatomical knowledge and expertise in performing this type of surgery. Overall, this work presents a modified technique that aims to improve the outcomes and quality of life for patients with splenic flexure colon cancer. Creating a tension-free anastomosis after extended left-sided colorectal resection is challenging. There is a negative impact on quality of life when an ileorectal anastomosis is created. The colorectal anastomosis performed after modified Rosi–Cahill or Deloyers' technique allows reduced small bowel bacterial overgrowth, achieves better water and sodium absorption, and altogether permits improved stool consistency. There are potential advantages of the Rosi–Cahill technique over other popular options such as Deloyers' procedure as there is no torsion of the ileocolic vessels and no mesenteric windows. A video was recorded showing a potential pitfall during Deloyers' technique resulting in the creation of a mesenteric window. The proper rotation of the colon during the modified Rosi–Cahill procedure was also filmed. Overall, this work presents a modified technique for reconstruction after left extended colectomy that aims to improve the outcomes and quality of life for patients with splenic flexure colon cancer. [ABSTRACT FROM AUTHOR]

We introduce the notion of conformal trajectories in three-dimensional Riemannian manifolds M3. Given a conformal vector field V ∈ 픛(M3), a conformal trajectory of V is a regular curve γ in M3 satisfying ∇γ′γ′ = qV × γ′, for some fixed nonzero constant q ∈ ℝ. In this paper, we study the conformal trajectories in the space forms ℝ3, 핊3 and ℍ3. For (non-Killing) conformal vector fields in 핊3 (respectively, in ℍ3), we prove that conformal trajectories have constant curvature and its torsion is a linear combination of trigonometric (respectively, hyperbolic) functions on the arc-length parameter. In the case of Euclidean space ℝ3, we obtain the same result for the radial vector field and characterizing all conformal trajectories. [ABSTRACT FROM AUTHOR]

The results of quantum chemical modeling of the structure and electronic properties of tellurium nanorods using two different approaches to describing the symmetry of these objects are presented. The first one is based on the consideration of tellurium nanorods within the framework of subgroups of the P3121 space group of a bulk tellurium crystal (crystallographic rod groups L3121 and L31), which specify the order of the helical axis strictly equal to 3. The second one considers nanorods within the framework of the line group theory, which allows for a continuous change in the order of the helical axis for 1D objects and by this way to discuss the effects of the nanorod torsion. It is shown that in the absence of symmetry restrictions, the order of the helical axis of tellurium nanorods is greater than the crystallographic value 3, but tends to it with increasing of nanorod thickness. Therefore, the corresponding rod groups should be considered only as groups to which the true line group symmetry of the nanorods asymptotically tends as their thickness increases. For nanorods obtained experimentally, the difference between the true and crystallographic helical axis orders is so small that it is practically invisible at the nanometer level, but manifests itself at the mesoscale, leading to a visually observable helical twist of tellurium nanorods (see A. Londoño-Calderon et al. Nanoscale, 2021, 13, 9606). The dependences of the electronic band gap of nanorods on torsion are presented. Nanorod of a certain thickness has its own features of the electronic structure, which can be explained by the evolution of the topology of electronic bands in the helical Brillouin zone. [ABSTRACT FROM AUTHOR]

We give a practical method to compute the 2-torsion subgroup of the Jacobian of a non-hyperelliptic curve of genus 3, 4 or 5. The method is based on the correspondence between the 2-torsion subgroup and the theta hyperplanes to the curve. The correspondence is used to explicitly write down a zero-dimensional scheme whose points correspond to elements of the 2-torsion subgroup. Using p-adic or complex approximations (obtained via Hensel lifting or homotopy continuation and Newton–Raphson) and lattice reduction we are then able to determine the points of our zero-dimensional scheme and hence the 2-torsion points. We demonstrate the practicality of our method by computing the 2-torsion of the modular Jacobians J0(N) for N = 42, 55, 63, 72, 75. As a result of this we are able to verify the generalized Ogg conjecture for these values. [ABSTRACT FROM AUTHOR]

Torsion of the hydatid of Morgagni is a rare condition which can cause acute abdominal pain in young female. We present a case report of a 13‐year‐old girl with acute abdominal pain and treated for torsion of the hydatid of Morgagni. Less than 20 cases of female younger than 18 years old with this condition are been described in the literature. Through our systematic review performed following the PRISMA statement, we want to emphasize the difficulty in diagnosis and the importance of considering this pathology in the differential diagnosis of acute abdomen in females with the aim of obtaining a timely surgical treatment to preserve fertility in these patients. [ABSTRACT FROM AUTHOR]

In the works of Achúcarro and Townsend and also by Witten, a duality between three-dimensional Chern–Simons gauge theories and gravity was established. In all cases, the results made use of the field equations. In a previous work, we were capable of generalizing Witten’s work to the off-shell cases, as well as to the four-dimensional Yang–Mills theory with de Sitter gauge symmetry. The price we paid is that curvature and torsion must obey some constraints under the action of the interior derivative. These constraints implied on the partial breaking of diffeomorphism invariance. In this work, we first formalize our early results in terms of fiber bundle theory by establishing the formal aspects of the map between a principal bundle (gauge theory) and a coframe bundle (gravity) with partial breaking of diffeomorphism invariance. Then, we study the effect of the constraints on the homology defined by the interior derivative. The main result is the emergence of a non-trivial homology in Riemann–Cartan manifolds. [ABSTRACT FROM AUTHOR]

Previous studies on bimetallic paddlewheel compounds have established a direct correlation between metal–metal distance and ligand torsion angles, leading to the rule that higher torsion results in longer metal‐metal bond distances. Here, the new discovery based on diarylformamidinate Ru₂⁵⁺ paddlewheel compounds [Ru2Cl(DArF)4] that show an opposite behavior is reported: higher torsions lead to shorter metal–metal distances. This discovery challenges the assumption that internal rotation solely impacts the δ bond. By combining experimental and theoretical techniques, it is demostrated that this trend is associated with previously overlooked π metal‐ligand interactions. These π metal‐ligand interactions are a direct consequence of the paddlewheel structure and the conjugated nature of the bidentate ligands. This findings offer far‐reaching insights into the influence of equatorial ligands and their π‐conjugation characteristics on the electronic properties of paddlewheel complexes. That this effect is not exclusive of diruthenium compounds but also occurs in other bimetallic cores such as ditungsten or dirhodium is demonstrated, and with other ligands showing allyl type conjugation. These results provide a novel approach for fine‐tuning the properties of these compounds with significant implications for materials design. [ABSTRACT FROM AUTHOR]

We obtain an upper bound on the lowest magnetic Neumann eigenvalue of a bounded, convex, smooth, planar domain with moderate intensity of the homogeneous magnetic field. This bound is given as a product of a purely geometric factor expressed in terms of the torsion function and of the lowest magnetic Neumann eigenvalue of the disk having the same maximal value of the torsion function as the domain. The bound is sharp in the sense that equality is attained for disks. Furthermore, we derive from our upper bound that the lowest magnetic Neumann eigenvalue with the homogeneous magnetic field is maximized by the disk among all ellipses of fixed area provided that the intensity of the magnetic field does not exceed an explicit constant dependent only on the fixed area. [ABSTRACT FROM AUTHOR]

It has been a widely-accepted belief that for a planar convex domain with two coordinate axes of symmetry, the location of maximal norm of gradient of torsion function is either linked to contact points of largest inscribed circle or connected to points on boundary of minimal curvature. However, we show that this is not quite true in general. Actually, we derive the precise formula for the location of maximal norm of gradient of torsion function on nearly ball domains in ℝn, which displays nonlocal nature and thus does not inherently establish a connection to the aforementioned two types of points. Consequently, explicit counterexamples can be straightforwardly constructed to illustrate this deviation from conventional understanding. We also prove that for a rectangular domain, the maximum of the norm of gradient of torsion function exactly occurs at the centers of the faces of largest (n - 1)-volume. [ABSTRACT FROM AUTHOR]

WE INVESTIGATE THE DEFORMATION OF AN ELASTIC ISOTROPIC ROD in the framework of a simplified micromorphic theory introduced by Forest and Sievert. In contrast with the classical micromorphic model, which includes 18 elastic constants, this theory is characterized by constitutive equations which involve 6 constants and a material length scale parameter to describe microstructure-dependent size effects. First, we formulate the equilibrium problem of a rod subjected to a resultant force and resultant moment acting on its plane ends. Then, we generalize the method of construction of the solution avoiding a priori assumptions proposed by Iesan in classical elasticity. The method leads to the decomposition of the general problem into the basic problems of extension, bending, torsion and flexure. The analytical solutions are obtained in a closed form and reduced to their classical elasticity counterparts when the microstructure effects are suppressed. The results are useful to obtain explicit solutions when the shape of the cross section is assigned and are preliminary to the solution of the problem of cylinders loaded on a lateral surface such as the Almansi--Michel problem. [ABSTRACT FROM AUTHOR]

We prove structure theorems for o-minimal definable subsets S ⊂ G of definable groups containing large multiplicative structures, and show definable groups do not have bounded torsion arbitrarily close to the identity. As an application, for certain models of n-step random walks X in G we show upper bounds P (X ∈ S) ≤ n - C and a structure theorem for the steps of X when P (X ∈ S) ≥ n - C ′ . [ABSTRACT FROM AUTHOR]

Improvements of reinforced concrete beams against the impact of torsional forces are among the most researched issues in construction studies. In this paper, repairing and strengthening reinforced concrete beams using ferrocement laminates attached onto the surface of the beams and exposed to torsion were reviewed. This study aims to reveal the efficacy of the wrapping sides of ferrocement laminates. Previous experimental studies were conducted by using SBR as a slurry for strengthening beams by ferrocement from two-and three-side wrapping. Alternatively, the influence of using SBR as an ingredient of the mortar on the performance of the strengthened beams under torsion was discussed. The results showed that ferrocement is a practical alternative strengthening component for rehabilitating and repairing reinforced concrete beams. It was demonstrated that three-side wrapping improves the torsional behaviour in comparison with two-side wrapping. Also, the SBR preserved the required joining until failure for all the strengthened beams. [ABSTRACT FROM AUTHOR]

Space elevators are a promising technology for future space transportation. The primary component of a space elevator is a tether deployed from a geostationary orbit towards the Earth and into deep space. Payloads can be transported using a climber moving along the tether. However, obtaining a deeper comprehension of the precise dynamics of a space elevator is challenging. The tether could have various deformations such as elongation, bending, and torsion owing to its flexible nature and the low level of vibration damping in space. Therefore, understanding those effects on the tether is essential for the design concept of a space elevator. Reproducing the behavior of space tether systems on the ground is challenging, which is primarily due to the scale of the system and the difficulty of accurately replicating a space environment. Thus, high-fidelity numerical analysis methods are required to analyze the dynamic response of space elevators precisely. Previously proposed analysis models of space tether systems with climbers have focused on elongation, bending, and rigid body motion of the tether, and the effect of torsional deformation has been neglected. However, a tether can be twisted easily owing to its low torsional stiffness. This study established high-fidelity numerical simulation models for space elevators considering large deformations including the torsion of a tether. This study developed a flexible multibody model with a moving climber using the absolute nodal coordinate formulation with 14 degrees of freedom. Further, the gravitational perturbation caused by the non-sphericity of the Earth was considered. Using the constructed model, the motion and deformation of nonequatorial space elevators caused by the climber motion and the disturbance in the space environment were investigated. The obtained results indicate that gravitational perturbation can induce torsional deformation, particularly at higher anchor latitudes. • Nonlinear finite element method for numerical simulation model for noneuqatorial space elevators. • Elongation, bending, torsion, and rigid body rotation of a tether considered. • Flexible multibody model with moving climber that considered torsional deformation. • Gravitational perturbation caused by the non-sphericity of the Earth considered. • Model used to investigate motion and deformation of nonequatorial space elevators. [ABSTRACT FROM AUTHOR]

Objective: In this study, we aimed to evaluate the relationship between blood pressure, left ventricular (LV) mass, and systolic function in American football (AF) players in Türkiye using deformation imaging and to compare it with conventional echocardiographic methods. Methods: AF players admitted to the Gazi University, Cardiology Unit between January 2021 and May 2023 were included in our study. The players were grouped as linemen or non-linemen according to their field positions. LV mass and ejection fraction (EF) were assessed using blood pressure measurements and conventional methods. Deformation analysis was performed by two-dimensional speckle tracking echocardiography, and LV torsion and global longitudinal strain values were calculated. Deformation analyses were compared with blood pressure and LV EF. Results: Players in the lineman position had higher blood pressure measurements. Although both groups of players had similar and intact LV EF values, players in the lineman position had significant changes in LV mass, LV global longitudinal strain, and LV torsion in relation to blood pressure measurements. Conclusion: AF players are at risk of hypertension. LV hypertrophy due to hypertension causes systolic dysfunction. Deformation analysis methods can detect subclinical myocardial damage even if the EF is intact. [ABSTRACT FROM AUTHOR]

Renewable energy markets, particularly wind energy, have experienced remarkable growth, predominantly driven by the urgent need for decarbonization in the face of accelerating global warming. As the wind energy sector expands and turbines increase in size, there is a growing demand for advanced composite materials that offer both high strength and low density. Among these materials, graphene stands out for its excellent mechanical properties and low density. Incorporating graphene reinforcement into wind turbine blades has the potential to enhance generation efficiency and reduce the construction costs of foundation structures. As a pilot study of graphene reinforcement on wind turbine blades, this study aims to investigate the variations of mechanical characteristics and weights between traditional fiberglass-based blades and those reinforced with graphene platelets (GPLs). A finite element model of the SNL 61.5 m horizontal wind turbine blade is used and validated by comparing the analysis results with those presented in the existing literature. Case studies are conducted to explore the effects of graphene reinforcement on wind turbine blades in terms of mechanical characteristics, such as free vibration, bending, and torsional deformation. Furthermore, the masses and fabrication costs are compared among fiberglass, CNTRC, and GPLRC-based wind turbine blades. Finally, the results obtained from this study demonstrate the effectiveness of graphene reinforcement on wind turbine blades in terms of both their mechanical performance and weight reduction. [ABSTRACT FROM AUTHOR]

A detailed comparative study was carried out to investigate the impact of unsymmetric openings on the torsional resistance of confined masonry rooms constructed in highly seismic-prone regions. To investigate in detail, an experimental and numerical investigation was carried out. Confined masonry wall panels with and without openings were experimentally tested to study the reduction in stiffness/lateral load-carrying capacity of walls due to the provision of openings. Further, a three-dimensional masonry room was tested experimentally to determine the torsion induced due to openings in confined masonry rooms. It was observed that on the provision of unsymmetric openings in confined masonry rooms, torsion was observed causing a reduction in the load-carrying capacity. The same was also confirmed using numerical simulation where it was revealed that on the provision of unsymmetric openings, 10% reduction in lateral load carrying capacity was observed in the confined masonry rooms as compared to the room with symmetric openings. Similarly, a lesser difference (0.1 mm) in the displacements between two corners of the wall opposite to the applied load was observed in the case of the confined masonry room having symmetrical openings on opposite sides. Therefore, it might be concluded that in highly seismic-prone regions, the provision of symmetric openings or utilizing other means of manipulating in-plane wall stiffness should be considered to reduce the impact of torsion. [ABSTRACT FROM AUTHOR]

In this paper, we present a geometric perspective on how to quantify the bending and the twisting of quantum curves traced by state vectors evolving under nonstationary Hamiltonians. Specifically, relying on the existing geometric viewpoint for stationary Hamiltonians, we discuss the generalization of our theoretical construct to time-dependent quantum-mechanical scenarios where both time-varying curvature and torsion coefficients play a key role. Specifically, we present a quantum version of the Frenet–Serret apparatus for a quantum trajectory in projective Hilbert space traced out by a parallel-transported pure quantum state evolving unitarily under a time-dependent Hamiltonian specifying the Schrödinger evolution equation. The time-varying curvature coefficient is specified by the magnitude squared of the covariant derivative of the tangent vector | T 〉 to the state vector | Ψ 〉 and measures the bending of the quantum curve. The time-varying torsion coefficient, instead, is given by the magnitude squared of the projection of the covariant derivative of the tangent vector | T 〉 to the state vector | Ψ 〉 , orthogonal to | T 〉 and | Ψ 〉 and, in addition, measures the twisting of the quantum curve. We find that the time-varying setting exhibits a richer structure from a statistical standpoint. For instance, unlike the time-independent configuration, we find that the notion of generalized variance enters nontrivially in the definition of the torsion of a curve traced out by a quantum state evolving under a nonstationary Hamiltonian. To physically illustrate the significance of our construct, we apply it to an exactly soluble time-dependent two-state Rabi problem specified by a sinusoidal oscillating time-dependent potential. In this context, we show that the analytical expressions for the curvature and torsion coefficients are completely described by only two real three-dimensional vectors, the Bloch vector that specifies the quantum system and the externally applied time-varying magnetic field. Although we show that the torsion is identically zero for an arbitrary time-dependent single-qubit Hamiltonian evolution, we study the temporal behavior of the curvature coefficient in different dynamical scenarios, including off-resonance and on-resonance regimes and, in addition, strong and weak driving configurations. While our formalism applies to pure quantum states in arbitrary dimensions, the analytic derivation of associated curvatures and orbit simulations can become quite involved as the dimension increases. Thus, finally we briefly comment on the possibility of applying our geometric formalism to higher-dimensional qudit systems that evolve unitarily under a general nonstationary Hamiltonian. [ABSTRACT FROM AUTHOR]

It is known that the Frenet–Serret apparatus of a space curve in three-dimensional Euclidean space determines the local geometry of curves. In particular, the Frenet–Serret apparatus specifies important geometric invariants, including the curvature and the torsion of a curve. It is also acknowledged in quantum information science that low complexity and high efficiency are essential features to achieve when cleverly manipulating quantum states that encode quantum information about a physical system. In this paper, we propose a geometric perspective on how to quantify the bending and the twisting of quantum curves traced by dynamically evolving state vectors. Specifically, we propose a quantum version of the Frenet–Serret apparatus for a quantum trajectory in projective Hilbert space traced by a parallel-transported pure quantum state evolving unitarily under a stationary Hamiltonian specifying the Schrödinger equation. Our proposed constant curvature coefficient is given by the magnitude squared of the covariant derivative of the tangent vector | T 〉 to the state vector | Ψ 〉 and represents a useful measure of the bending of the quantum curve. Our proposed constant torsion coefficient, instead, is defined in terms of the magnitude squared of the projection of the covariant derivative of the tangent vector | T 〉 , orthogonal to both | T 〉 and | Ψ 〉. The torsion coefficient provides a convenient measure of the twisting of the quantum curve. Remarkably, we show that our proposed curvature and torsion coefficients coincide with those existing in the literature, although introduced in a completely different manner. Interestingly, not only we establish that zero curvature corresponds to unit geodesic efficiency during the quantum transportation in projective Hilbert space, but we also find that the concepts of curvature and torsion help enlighten the statistical structure of quantum theory. Indeed, while the former concept can be essentially defined in terms of the concept of kurtosis, the positivity of the latter can be regarded as a restatement of the well-known Pearson inequality that involves both the concepts of kurtosis and skewness in mathematical statistics. Finally, not only do we present illustrative examples with nonzero curvature for single-qubit time-independent Hamiltonian evolutions for which it is impossible to generate torsion, but we also discuss physical applications extended to two-qubit stationary Hamiltonians that generate curves with both nonzero curvature and nonvanishing torsion traced by quantum states with different degrees of entanglement, ranging from separable states to maximally entangled Bell states. In the Appendix C, we examine the different curvature and torsion characteristics of the three qubit | GHZ 〉 and | W 〉 states under evolution by a quantum Heisenberg Hamiltonian. [ABSTRACT FROM AUTHOR]

A series of five 3,6‐divinyl‐N‐arylcarbazoles‐bridged diruthenium complexes with a general formula of [{Ru(CO)Cl(PiPr3)2}2(μ‐(CH=CH)2‐(N‐arylcarbazole)‐3,6); aryl = 4‐anisyl; [1a], 4‐tolyl; [1b], phenyl; [1c], 4‐(trifluoromethyl)phenyl; [1d], and 4‐nitrophenyl; [1e]] were successfully synthesized. These new square‐pyramidal bis(ruthenium‐vinyl)‐type complexes were characterized in their neutral state via classical NMR, UV/Vis, and IR spectroscopic techniques and in their three various accessible oxidized states via electrochemical techniques and ESR spectroscopy along with UV/Vis/NIR and IR spectroelectrochemistry as well as with DFT calculations. Our obtained results were compared with the closely related bis(ruthenium‐vinyl)‐appended N‐(4‐anisyl)diphenylamine TAARu2 counterpart of [1a]. Electrochemical studies on complexes [1a]–[1e] revealed three consecutive, chemically and electrochemically, well‐separated, reversible one‐electron oxidation processes at low and well‐accessible potentials. Their half‐wave potential separations ΔE½ between the individual redox waves and the derived comproportionation constants Kc1–Kc3 attribute to noteworthy stability of every oxidized intermediate state. The concert electrochemical and UV/Vis/NIR/IR spectro(electro)scopic results on these rotationally restricted N‐arylcarbazoles‐bridged bis(ruthenium‐alkenyl)‐type complexes [1a]–[1e] confirmed the relative weakness influence of altering the para‐substituent on the peripheral aryl ring. This is most probably due to the sizable torsion with nearly 55° between the co‐planarity of the carbazole heterocycle core and the peripheral N‐bound aryl ring. In their mixed‐valent (MV) radical states [1a]+–[1e]+, the observed pattern of two well‐separated Ru(C≡O) bands mirrors the uneven distribution of the uni‐positive charge over the two chemically equivalent bis(ruthenium‐vinyl) moieties as indicated by classical class II of Robin–Day classification of MV states. [ABSTRACT FROM AUTHOR]

This article discusses the fatigue behavior of pultruded fiberglass tubes under tension, compression, and torsion. The study aims to investigate the mechanical properties and damage accumulation of pultruded composites. The researchers conducted static and fatigue tests to determine the material's strength and stiffness, as well as its damage mechanisms. The results provide insights into the fatigue behavior and damage mechanisms of pultruded fiberglass tubes. Additionally, the document includes a list of references for research articles related to fatigue damage and degradation in composite materials, as well as three research articles on the mechanical properties of different materials. These articles provide valuable insights for researchers and engineers in various fields. [Extracted from the article]

Purpose: To explore the relationship between preoperative J‐sign grading and structural bone abnormalities in patients with recurrent patellar dislocation (RPD). Methods: A retrospective study was conducted on RPD patients over 5 years. Patients were categorised based on J‐sign grade into low (J‐ and J1+), moderate (J2+) and high groups (J3+). Trochlear dysplasia (TD) and osseous structures (femoral anteversion angle [FAA], knee torsion, tibial tuberosity‐trochlear groove [TT‐TG] distance, Caton–Deschamps index) were assessed and grouped according to risk factor thresholds. The χ2 test was used to compare composition ratio differences of structural bone abnormalities among the groups. Results: A total of 256 patients were included, with 206 (80.5%) females. The distribution of J‐sign grade was as follows: 89 knees (34.8%) of low grade, 86 moderate (33.6%) and 81 high (31.6%). Among the five structural bone abnormalities, TD was the most common with a prevalence of 78.5%, followed by increased TT‐TG at 47.4%. Excessive tibiofemoral rotation had the lowest occurrence at 28.9%. There were 173 (67.6%) patients who had two or more abnormalities, while 45 (17.6%) had four to five bony abnormalities. Among patients with any bony abnormality, the proportion of high‐grade J‐sign surpassed 40%. Patients with moderate and high‐grade J‐sign had more increased FAA and more pronounced patella alta (all p < 0.001). The proportion of excessive knee torsion and TD increased with increasing each J‐sign grade, with the more notable tendency in knee torsion (high vs. moderate vs. low‐grade: 61% vs. 22% vs 7%, p < 0.001). Furthermore, the higher J‐sign grade was also associated with more combined bony abnormalities (p < 0.001). In the high‐grade J‐sign group, 90.2% of the knees had two or more bony risk factors and 40.7% had four or more, which were significantly higher than the moderate and low‐grade J‐sign groups (40.7% vs. 11.6% vs. 2.2%, p < 0.001). Conclusion: In patients with a high‐grade J‐sign, over 90% of the lower limbs had two or more structural bone risk factors, and more than 40% had four or more. These proportions were significantly higher compared to knees with low‐grade and moderate J‐sign. In clinical practice, when treating high‐grade patellar mal‐tracking, it is important to focus on and correct these strongly correlated abnormal bone structures. Level of Evidence: Level III. [ABSTRACT FROM AUTHOR]

A celebrated theorem of Serrin asserts that one overdetermined condition on the boundary is enough to obtain radial symmetry in the so-called one-phase overdetermined torsion problem. It is also known that imposing just one overdetermined condition on the boundary is not enough to obtain radial symmetry in the corresponding multi-phase overdetermined problem. In this paper we show that, in order to obtain radial symmetry in the two-phase overdetermined torsion problem, two overdetermined conditions are needed. Moreover, it is noteworthy that this pattern does not extend to multi-phase problems with three or more layers, for which we show the existence of nonradial configurations satisfying countably infinitely many overdetermined conditions on the outer boundary. [ABSTRACT FROM AUTHOR]

Structural stability tests on two‐span channel members in bending, axial compression and torsion The use of slender steel members promotes the competitiveness of steel structures in structural engineering. However, these members often necessitate stability verifications. Global research activities in this field have so far mainly focussed on single‐span members with doubly symmetric cross‐sections. For mono‐symmetric sections such as channels, only a few design models exist based on experimental evidence. Moreover, the potential of structural systems such as multi‐span members is yet not entirely exploited in the normative verification models. Therefore, this paper presents a comprehensive experimental study on the stability behaviour of two‐span members with steel channels under combined loading. Five‐point bending tests were conducted to determine the load‐bearing capacities and to experimentally analyse the influence of the constructional detail of the central support, the axial load, the slenderness ratio and other parameters on the load‐bearing behaviour. The article provides the scientific basis for extending the scope of the stability verification for members subjected to bending, axial compression and torsion in Annex C.2 of the novel EN 1993‐1‐1:2022 to two‐span channel members. [ABSTRACT FROM AUTHOR]

In this paper, we report on a computation demonstrating that if A and B are nonempty subsets of a torsion-free group such that A B has no unique product, then | A | + | B | ≥ 1 6. Moreover, this bound is sharp, as there are examples where | A | = | B | = 8 , and in fact A = B for at least two such examples. More generally, when | A | is small, we find lower bounds on | B |. One consequence of this work is that any counterexample to Kaplansky's zero-divisor conjecture must be quite complicated, if it exists at all. Another advance is that we give new examples of torsion-free groups that are not unique product groups. [ABSTRACT FROM AUTHOR]

Let F be an infinite field of characteristic p ≠ 2 , G be a group, and * be an involution of G extended linearly to an involution of the group algebra FG. In the literature, group identities on units U (FG) and on symmetric units U + (FG) = { α ∈ U (FG) | α * = α } have been considered. Here, we investigate normalized Laurent polynomial identities (as a generalization of group identities) on U + (FG) under the conditions that either p > 2 or F is algebraically closed. For instance, we show that if G is torsion and U + (FG) satisfies a normalized Laurent polynomial identity, then U + (FG) satisfies a group identity and FG satisfies a polynomial identity. [ABSTRACT FROM AUTHOR]

In this case report, we present an unusual clockwise torsion of left colon around mesenteric root in a 10‐month‐old Arab filly, highlighting the clinical presentation, diagnostic approach and successful surgical intervention. A 10‐month‐old Arab filly weighing approximately 250 kg was referred with signs of acute abdominal pain. The history revealed anorexia, restlessness and severe abdominal pain that had begun the previous day. The local practitioner had previously administered flunixin meglumine, an analgesic, but it proved ineffective in relieving the pain. Upon physical examination, the filly exhibited sweating, a body temperature of 38.5°C, tachycardia (65 beats per minute) and tachypnea (25 breaths per minute). Due to the severity of the colic and the lack of response to the conservative treatments, surgical intervention was deemed necessary. An exploratory midline celiotomy was performed to evaluate the abdominal organs. During the examination, no obvious primary lesions were identified in the evaluated organs. However, a restriction in exteriorizing the left colon's length was observed. Further examination revealed an unusual clockwise torsion of the left colon that displaced in left to the right side around the mesenteric root; thereby, pelvic flexure was located in the normal anatomical position with a short length. To the best of our knowledge, this is the first reported case of clockwise torsion and an atypical displacement of the left colon in horses. The surgical correction of the displacement was successfully performed. The filly showed improvement post‐surgery and did not exhibit any complications during the recovery period. [ABSTRACT FROM AUTHOR]

In order to prevent damage to the support equipment caused by rock burst, a torsion plate energy absorption member is designed to be used with hydraulic columns. Explicit dynamic simulation is used and compared with the tests. The equations of structural parameters to the mean value of the reaction force (F mean), specific energy absorption (SEA), and mean squared deviation (σ) are constructed based on the response surface method. The structural parameters are optimized using MOPSO. The results indicate that the torsion plate exhibits excellent energy absorption characteristics. The error rate of the simulation compared to the test is less than 5%, indicating a high level of simulation accuracy. All three sets of response fitted equations have R 2 above 0.97, indicating a good fit. The three evaluation indexes demonstrate a trend of increasing then decreasing as the torsion angle increases. The wall thickness is positively correlated with the influence of each parameter index, while the effect of fillet radius is reversed. The maximum relative error of the predicted value is 9.50%. After optimization, the F mean is effectively increased by more than 78%, the SEA is increased by more than 24.72%. The σ is increased by 8.31%, the optimization effect is remarkable. [Display omitted] [ABSTRACT FROM AUTHOR]

Liver lobe torsion has been reported in many species, with frequent reports in rabbits. Here we describe caudate liver lobe torsion and concurrent necrohemorrhagic typhlocolitis in a Patagonian mara (syn: Patagonian cavy, Patagonian hare, Dolichotis patagonum). Following acute death, postmortem examination findings included torsion of the hepatic caudate process, which had fibrous adhesions to the pancreas indicating chronicity. The cecal apex and proximal 30 cm of colon had regionally reddened serosa and diffusely roughened and reddened mucosa with brown-red and granular luminal contents. Key histologic findings included massive necrosis of the torsed hepatic caudate lobe, consistent with infarction, necrotizing hepatitis in remaining areas of liver, necrohemorrhagic typhlocolitis, adrenocortical necrosis and hemorrhage, and renal tubular degeneration and necrosis with tubular casts. Bacterial culture of cecal contents yielded pure growth of Salmonella spp. Death was attributed to toxemia or bacteremia resulting from Salmonella spp. infection, as the hepatic lobe torsion appeared chronic. It was undetermined if the liver lobe torsion predisposed to gastrointestinal compromise and infection. Patagonian maras have some anatomical similarities to rabbits and are highly cursorial, not dissimilar to hares, Lepus spp. We speculate that these characteristics may increase the likelihood of hepatic caudate lobe torsion in this species. [ABSTRACT FROM AUTHOR]

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The study concerns the comparative analysis of selected solutions of thin-walled structures subjected to constrained torsion, representing the simulation of wing areas weakened by large cutouts. The chosen variants of stiffening were based on the concept of so-called "Misztal torsion box", used in the wing of the PZL-37 aircraft. A series of numerical analyses were conducted, aiming to compare selected variants of structures with reinforcements and a reference structure based on a traditional design scheme. The calculations were performed using software based on the finite element method. An analysis of the stress and displacement distribution of the examined structure was conducted, and the results demonstrating the advantages of the proposed structural solution were presented. [ABSTRACT FROM AUTHOR]

Let q$q$ be a prime power and F=Fq(T)$F=\mathbb {F}_q(T)$ be the rational function field over Fq$\mathbb {F}_q$, the field with q$q$ elements. Let ϕ$\phi$ be a Drinfeld module over F$F$ and p$\mathfrak {p}$ be a nonzero prime ideal of A:=Fq[T]$A:=\mathbb {F}_q[T]$. Over the constant Zp$\mathbb {Z}_p$‐extension of F$F$, we introduce the fine Selmer group associated to the p$\mathfrak {p}$‐primary torsion of ϕ$\phi$. We show that it is a cofinitely generated module over Ap$A_{\mathfrak {p}}$. This proves an analogue of Iwasawa's μ=0$\mu =0$ conjecture in this setting, and provides context for the further study of the objects that have been introduced in this article. [ABSTRACT FROM AUTHOR]

We consider the problem of producing a ruled Möbius band by subjecting an unstretchable, homogeneous, isotropic, elastic material surface material surface in a circular helicoidal reference configuration to a deformation that is isometric and chirality preserving. We find that such a Möbius band is completely determined by the unit binormal of the Frenet frame of its midline, which must be a geodesic and must have uniform torsion inversely proportional to the pitch of the helicoidal reference configuration. Granted that the energy density of the material surface depends quadratically on the mean curvature of its deformed configuration, we show that the total energy stored in producing a ruled Möbius band as described reduces, in closed form and without approximation, to an integral over the midline of the Möbius band. We formulate and numerically solve a constrained variational problem for finding relative minima of the dimensionally reduced bending energy and construct corresponding stable Möbius bands. The only input parameter entering our variational problem is the number ν of turns in a helicoidal reference configuration. We only find solutions if ν exceeds a certain threshold, which we compute to machine precision. Above that threshold, an interplay between the operative constraints leads to a multiplicity of coexisting stable solutions with n ≥ 3 half twists. For each n ≥ 3 , we construct an energetically optimal Möbius band which exhibits n -fold rotational symmetry. All other energy minima yield Möbius bands which lack symmetry. To our knowledge, this study contains the first examples of stable Möbius bands produced by isometrically deforming reference configurations that are not flat. [ABSTRACT FROM AUTHOR]

Objective: Ovarian torsion (OT) represents a severe gynecological emergency in female pediatric patients, necessitating immediate surgical intervention to prevent ovarian ischemia and preserve fertility. Prompt diagnosis is, therefore, paramount. This retrospective study set out to assess the utility of combined clinical, ultrasound, and laboratory features in diagnosing OT. Methods: The authors included 326 female pediatric patients aged under 14 years who underwent surgical confirmation of OT over a five-year period. Logistic regression analysis was employed to pinpoint factors linked with OT, and the authors compared clinical presentation, laboratory results, and ultrasound characteristics between patients with OT (OT group) and without OT (N-OT group). The authors conducted receiver operating characteristic (ROC) curve analysis to gauge the predictive capacity of the combined features. Results: Among 326, OTwas confirmed in 24.23 % (79 cases) of the patients. The OT group had a higher incidence of prenatal ovarian masses than the N-OT (22 cases versus 7 cases) (p < 0.0001). Similarly, the authors observed significant differences in the presence of lower abdominal pain, suspected torsion on transabdominal ultrasound, and a high neutrophil-lymphocyte ratio (NLR > 3) between the OT and non-OT groups (p > 0.05). Furthermore, when these parameters were combined, the resulting area under the curve (AUC) was 0.868, demonstrating their potential utility in OT diagnosis. Conclusion: This study demonstrates a prediction model integrating clinical, laboratory, and ultrasound findings that can support the preoperative diagnosis of ovarian torsion, thereby enhancing diagnostic precision and improving patient management. Future prospective studies should concentrate on developing clinical predictive models for OT in pediatric patients. [ABSTRACT FROM AUTHOR]

To increase the package space for the battery pack in the rear of battery electric vehicles (BEVs), and thus extend their driving range, a novel rear axle concept called the multi-link torsion axle (MLTA) has been developed. In this work, the kinematic design was extended with an elastokinematic concept, and the MLTA was designed in CAD and realized as a prototype. It was then integrated into a B-class series-production vehicle by adding masses in different locations of the vehicle to replicate the mass distribution of a BEV. Both objective and subjective vehicle dynamic evaluations were conducted, which included kinematic and compliance tests, constant-radius cornering, straight-line braking, and a frequency response test, as well as subjective evaluations by both expert and normal drivers. These test results were analyzed and compared to a production vehicle. It can be concluded that the vehicle dynamic performance of the MLTA-equipped vehicle is, overall, 0.67 grades lower than that of the comparable production vehicle on a 10-grade scale. According to OEM experts, this deficit can be eliminated by tuning the different components of the MLTA and meeting the tolerance requirements of series production vehicles. [ABSTRACT FROM AUTHOR]

We carry out a study of groups G in which the index of any infinite subgroup is finite. We call them restricted-finite groups and characterize finitely generated not torsion restricted-finite groups. We show that every infinite restricted-finite abelian group is isomorphic to Z×K or Zp∞ ×K, where K is a finite group and p is a prime number. We also prove that a group G is infinitely generated restricted-finite if and only if G = AT where A and T are subgroups of G such that A is normal quasi-cyclic and T is finite. As an application of our results, we show that if G is not torsion with finite G′ and the group-ring RG has restricted minimum condition, then R is a semisimple ring and G ∼= T ⋊ Z, where T is finite whose order is unit in R. The converse is also true with certain conditions including G = T × Z. [ABSTRACT FROM AUTHOR]

Hydrogen-enriched compressed natural gas (HCNG) technology is one of the most critical developments in the natural gas industry. To ensure the safe utilization of HCNG, the mixing effect of the two gases must be characterized and evaluated. In this paper, five types of static mixers were developed and numerically simulated. The results showed that the velocity, hydrogen blending ratio (HBR), mixer types, element aspect ratio, torsion angle, and number of elements affected the mixing effect to different degrees. Specifically, the increase in velocity and HBR improved the mixing uniformity of hydrogen and methane, but with a limited impact. Additionally, the mixing uniformity increased with the increase in the torsion angle and the number of elements, as well as the decrease in the element aspect ratio. Overall, the torsion angle had the most significant effect on mixing uniformity. Comparing the five types of static mixers, it was found that the new LPD static mixers yielded the best mixing effect, while the Y-type static mixers had the worst mixing effect. It is noted here that all the static mixers could satisfy the mixing uniformity requirements of industrial production. [Display omitted] • The influence of five models on the gas mixing effect is comprehensively analyzed. • The gas mixing effect is analyzed by three evaluation indexes. • The effects of operating conditions and spoilers on the mixing effect are studied. • The new LPD static mixer has the best effect on gas mixing. [ABSTRACT FROM AUTHOR]

High-entropy alloys (HEAs) have garnered significant attention for their exceptional properties, with eutectic high-entropy alloys (EHEAs) emerging as particularly notable due to their incorporation of eutectic structures comprising soft and hard phases. This study investigated the influence of shear strain on the microstructural refinement and mechanical properties of AlCoCrFeNi2.1 EHEAs, which were subjected to high-pressure torsion (HPT) at room temperature under a pressure of 6 GPa across 0.5 to 3 turns, compared to the initial material. After HPT treatment, significant grain refinement occurred due to strong shear strain, evidenced by the absence of B2 phase peaks in X-ray diffraction (XRD) analysis. Microhardness increased substantially post-HPT, reaching a saturation point at approximately 575 HV after three turns, significantly higher than that of the original sample. Moreover, the ultimate tensile strength of HPT-treated specimens reached around 1900 MPa after three revolutions, compared to approximately 1100 MPa for the as-cast alloy, with a mixed fracture mode maintained. This investigation underscores the efficacy of HPT in enhancing the mechanical properties of AlCoCrFeNi2.1 EHEAs through microstructural refinement induced by shear deformation, offering insights into the design and optimization of advanced HEAs for various engineering applications. [ABSTRACT FROM AUTHOR]

AbstractThis work describes the elastokinematic design and optimization for a new, package space saving rear suspension especially intended for small battery electric vehicles. Mainly for reasons of cost and weight efficiency, the twist-beam axle is widely used, especially in the A and B segments. One of the main disadvantages of twist-beam axles is that they limit the rear package space because of the torsion profile. The basic idea of this work was to reverse the installation direction of the twist-beam axle to create an additional package space for the battery. To obtain an optimized elastokinematic design, a new algorithm was introduced that allows modeling of the elastokinematic behavior of the new mechanism. A Pareto optimization of the body connecting bushing was performed, revealing that a specific spatial orientation enables effective compensation for camber compliance deficits. Finally, the Pareto-optimized elastokinematic design was compared to compliance measurement results of a prototype vehicle equipped with the new suspension concept. [ABSTRACT FROM AUTHOR]

The conformal nature of smooth curves in R 3 is characterised by conformal length, curvature and torsion. We present a derivation of these conformal parameters via a limiting process using inscribed polygons with circular edges. The procedure is based on elementary geometry in R 3 only and similar to the rectification of curves in the metrical case. It seems to be not available in the literature so far. [ABSTRACT FROM AUTHOR]

Background: Persistent truncus arteriosus is a rare congenital cyanotic heart defect characterized by a single ventricular outflow tract. Without surgical intervention, it has a poor prognosis in infancy. Here, we report an adult female patient with uncorrected truncus arteriosus type I, who presented with acute-onset abdominal pain due to torsion of a small bowel gastrointestinal stromal tumor (GIST). Case Report: A 41-year-old woman came to our Emergency Department with acute-onset lower abdominal pain for 2 days. Congenital heart disease, truncus arteriosus, had been diagnosed at birth, and there had been no surgical intervention. Abdominal computed tomography revealed a 10×9×12-cm mixed-density mass in the pelvic capacity. Transthoracic echocardiography revealed a 33-mm ventricular septal defect. The ascending aorta originated mainly from the right ventricle, and the pulmonary artery originated from the beginning of the aorta (type I truncus arteriosus, according to Collett and Edwards classification). After a quick and detailed preoperative workup, the patient underwent tumor resection by open surgery with general anesthesia. Conclusions: This is the first case to report emergency surgery for a patient with uncorrected persistent truncus arteriosus due to torsion of a small bowel GIST. A multidisciplinary team with deep understanding of the disease entity was crucial. By considering the fixed hemodynamic and respiratory physiology, overtreatment and unrealistic goals were avoided. Eventually, the patient was discharged after being hospitalized for 2 weeks. [ABSTRACT FROM AUTHOR]

Introduction: Proximal humerus fractures are usually treated with locking plates, which could present recurrence, screw penetration, joint varization. The push–pull principle was introduced to prevent these risks and showed promising results; a dedicated design was then developed and this feasibility study aims to compare the biomechanical performances of such dedicated push–pull plate with the traditional locking plate using finite elements. Materials and methods: The humerus geometry was obtained from Sawbone CT-scans; the geometries of a traditional locking plate and of the dedicated push–pull one were used. A fracture was added below the humeral head and the plates were virtually implanted. The wire pulling mechanism was simulated connecting the plate to the humeral head apex, considering two levels of tension. Three testing set-ups (axial, torsion and compression bending) were simulated. Stress distributions on bone, plate and screws were measured. Results: Stress distribution on the distal humerus was similar for both plates. Stress distribution on the proximal humerus was more homogeneous for the push–pull model, showing less unloaded sections (up to 78%). The different levels of tension applied to the wire returned slight differences in terms of stress values, but the comparison with the traditional approach gave similar outcomes. Conclusions: More homogeneous stress distribution is found with the push–pull plate in all three testing set-ups, showing lower unloaded areas (and thus lower stress-shielding) compared to the traditional plate; the screws implemented returned to be all loaded in at least one of the set-ups, thus showing that they all contribute to plate stability. [ABSTRACT FROM AUTHOR]