bluuebunny/crossref_metadata_2025_split huggingface dataset:
Machining Simulation in Focused Ion Beam Sputtering
Authors: Matsumura Takashi , Ogasawara Ryosuke 
Published: February 2020

Abstract
Focused ion beam (FIB) has been applied to micro/nanometer-scale fabrication to control surface functions with the surface topographies. Although the resolution of the FIB sputtering is in the nanometer-scale range in positioning, the removal shape in the depth direction cannot be controlled numerically. This study presents a removal model to predict the surface profile in the simulation. The removal rate depends on not only the ion beam intensity but also the incident angle onto the surface to be structured. The removal model considers the effects of those two parameters to control the surface profile in sputtering. The removal rates in sputtering of the inclined surfaces at incident angles are associated with a Gaussian distribution. The parameters in the model were identified to minimize the simulation error validated against the sputtering tests. The presented model was applied to simulate the microscale structures on surfaces using the identified parameters. The simulation was validated in comparison with the actual machined shapes.
Multi-Excitation Magnetic Resonance Elastography of the Brain: Wave Propagation in Anisotropic White Matter
Authors: Smith Daniel R. , Guertler Charlotte A. , Okamoto Ruth J. , Romano Anthony J. , Bayly Philip V. , Johnson Curtis L. 
Published: February 2020

Abstract
Magnetic resonance elastography (MRE) has emerged as a sensitive imaging technique capable of providing a quantitative understanding of neural microstructural integrity. However, a reliable method for the quantification of the anisotropic mechanical properties of human white matter is currently lacking, despite the potential to illuminate the pathophysiology behind neurological disorders and traumatic brain injury. In this study, we examine the use of multiple excitations in MRE to generate wave displacement data sufficient for anisotropic inversion in white matter. We show the presence of multiple unique waves from each excitation which we combine to solve for parameters of an incompressible, transversely isotropic (ITI) material: shear modulus, μ, shear anisotropy, ϕ, and tensile anisotropy, ζ. We calculate these anisotropic parameters in the corpus callosum body and find the mean values as μ = 3.78 kPa, ϕ = 0.151, and ζ = 0.099 (at 50 Hz vibration frequency). This study demonstrates that multi-excitation MRE provides displacement data sufficient for the evaluation of the anisotropic properties of white matter.
Using an Impact Hammer to Estimate Elastic Modulus and Thickness of a Sample During an Osteotomy
Authors: Hubert Alexis , Rosi Giuseppe , Bosc Romain , Haiat Guillaume 
Published: February 2020

Abstract
Performing an osteotomy with a surgical mallet and an osteotome is a delicate intervention mostly based on the surgeon proprioception. It remains difficult to assess the properties of bone tissue being osteotomized. Mispositioning of the osteotome or too strong impacts may lead to bone fractures which may have dramatic consequences. The objective of this study is to determine whether an instrumented hammer may be used to retrieve information on the material properties around the osteotome tip. A hammer equipped with a piezo-electric force sensor was used to impact 100 samples of different composite materials and thicknesses. A model-based inversion technique was developed based on the analysis of two indicators derived from the analysis of the variation of the force as a function of time in order to (i) classify the samples depending on their material types, (ii) determine the materials stiffness, and (iii) estimate the samples thicknesses. The model resulting from the classification using support vector machines (SVM) learning techniques can efficiently predict the material of a new sample, with an estimated 89% prediction performance. A good agreement between the forward analytical model and the experimental data was obtained, leading to an average error lower than 10% in the samples thickness estimation. Based on these results, navigation and decision-support tools could be developed and allows surgeons to adapt their surgical strategy in a patient-specific manner.
Computer-Controlled Biaxial Bioreactor for Investigating Cell-Mediated Homeostasis in Tissue Equivalents
Authors: Eichinger J. F. , Paukner D. , Szafron J. M. , Aydin R. C. , Humphrey J. D. , Cyron C. J. 
Published: February 2020

Abstract
Soft biological tissues consist of cells and extracellular matrix (ECM), a network of diverse proteins, glycoproteins, and glycosaminoglycans that surround the cells. The cells actively sense the surrounding ECM and regulate its mechanical state. Cell-seeded collagen or fibrin gels, so-called tissue equivalents, are simple but powerful model systems to study this phenomenon. Nevertheless, few quantitative studies document the stresses that cells establish and maintain in such gels; moreover, most prior data were collected via uniaxial experiments whereas soft tissues are mainly subject to multiaxial loading in vivo. To begin to close this gap between existing experimental data and in vivo conditions, we describe here a computer-controlled bioreactor that enables accurate measurements of the evolution of mechanical tension and deformation of tissue equivalents under well-controlled biaxial loads. This device allows diverse studies, including how cells establish a homeostatic state of biaxial stress and if they maintain it in response to mechanical perturbations. It similarly allows, for example, studies of the impact of cell and matrix density, exogenous growth factors and cytokines, and different types of loading conditions (uniaxial, strip-biaxial, and biaxial) on these processes. As illustrative results, we show that NIH/3T3 fibroblasts establish a homeostatic mechanical state that depends on cell density and collagen concentration. Following perturbations from this homeostatic state, the cells were able to recover biaxial loading similar to homeostatic. Depending on the precise loads, however, they were not always able to fully maintain that state.
Alternative Representation of the Shoulder Orientation Based on the Tilt-and-Torsion Angles
Authors: Campeau-Lecours Alexandre , Vu Dinh-Son , Schweitzer Frédéric , Roy Jean-Sébastien 
Published: February 2020

Abstract
The International Society of Biomechanics (ISB) has proposed standardized recommendations for recording human joint motion. The Euler angles—the orientation representation currently proposed by the ISB—have two drawbacks, namely, the issue of singularities (gimbal lock) and the difficulty to obtain clinical and interpretable orientation representation for compound movements. The orientation representation of the shoulder joint with the Euler angles is particularly challenging due to its broad range of motion. This paper proposes and evaluates an alternative orientation representation for shoulder movement based on the tilt-and-torsion representation, a method that aims at providing a more clinically interpretable solution for describing joint movements compared to the standard Euler angles. Three studies were performed to compare the different orientation representation methods. The first two studies consist in simulations of arm elevation in different planes. The third study is an experiment using inertial-measurement-units with one test subject performing shoulder elevation movements in different planes. The tilt-and-torsion representation is then compared with different Euler angle conventions. The results show that Euler angles are biased or clinically uninterpretable for compound movements. Conversely, tilt-and-torsion representation does not suffer from these limitations. Although not extensive, the experiments suggest that the tilt-and-torsion representation has the potential to better represent human movements and provide more clinically interpretable results than the Euler angles.
Simulation of the Multiphysical Coupling Behavior of Active Hearing Mechanism Within Spiral Cochlea
Authors: Ma J. , Yao W. , Hu B. 
Published: February 2020

Abstract
Nobel Laureate von Békésy first presented traveling wave theory, which explains the vibration mechanism of the basilar membrane (BM) of cochlea in 1960, and thus the mysterious veil of passive phonoreceptive mechanism of human cochlea was unveiled. However, the interpretation of active phonoreceptive mechanism of human cochlea has been a major medical problem for mankind. The active mechanism can be reflected in structures and the perilymph where a series of complex coupling nonlinear motion process is observed in the cochlea. Because the cochlea is small and complex, vibration data of the whole BM are not yet available from existing experiments. To address the problem, first, the motion equations of the organ of Corti (OHC) are established, and the circuit equations of the outer hair cells (OHCs) in the perilymph and the relationship between the motion of the outer hair cells and the electromotile force are derived. Then the active feedback force on the BM is obtained. Finally, an analytical–numerical combination model, where both macrostructures and microstructures of cochlea are included, is established. The model not only vividly depicts the spatial helical body and biological materials of the cochlea but also reflects the fluid–solid coupling nonlinear motion of cochlear structures in the electrical environment. Thus, the active hearing mechanism of cochlea is revealed.
The Effect of Strain Rate on the Stress Relaxation of the Pig Dermis: A Hyper-Viscoelastic Approach
Authors: Dwivedi Krashn K. , Lakhani Piyush , Kumar Sachin , Kumar Navin 
Published: February 2020

Abstract
The understanding of strain rate-dependent mechanical properties of the skin is important for accurate prediction of its biomechanics under different loading conditions. This study investigated the effect of strain rate, i.e., 0.025/s (low), 0.5/s (medium), and 1.25/s (high), ranging in the physiological loading rate of connective tissue, on the stress-relaxation response of the porcine dermis. Results show that in the initial phase of the relaxation, the value of stress relaxation (extent of relaxation) was found higher for high strain rate. However, the equilibrium stress was found strain rate independent. A Mooney–Rivlin-based five-term quasi-linear viscoelastic (QLV) model was proposed to determine the effect of strain rate on the stress-relaxation behavior of the porcine dermis. The value of relaxation modulus G1 and G2 were found higher for the high strain rate, whereas the reverse trend was observed for G3, G4, and G5. Moreover, the value of time constants τ1,τ2,τ3τ4, and τ5 were found higher for low strain rate. Statistical analysis shows no significant difference in the values of G5, τ4, and τ5 among the three strain rates. The proposed model was found capable to fit the stress-relaxation response of skin with great accuracy, e.g., root-mean-squared-error (RMSE) value equal to 0.015 ± 0.00012 MPa. Moreover, this hyper-viscoelastic model can be utilized: to quantify the effects of age and diseases on the skin; to simulate the stresses on sutures during large wound closure and impact loading.
Modeling and Verification of a RANCF Fluid Element Based on Cubic Rational Bezier Volume
Authors: Ma Liang , Wei Cheng , Ma Chao , Zhao Yang 
Published: February 2020

Abstract
This investigation is focused on developing a novel three-dimensional rational absolute nodal coordinate formulation (RANCF) fluid element based on cubic rational Bezier volume. The new fluid element can describe liquid columns with initially curved configurations precisely, performing better than the conventional absolute nodal coordinate formulation (ANCF) fluid element. A new kinematic description, which employs a different interpolation function to describe the displacement field, makes this element a true difference. The shape function is no longer calculated by an incomplete polynomial or nonrational B-spline function, replaced by the rational Bezier function. Dynamical model or governing equation of the RANCF fluid element is built based on the constitutive equation of fluid, momentum, and constraint equation. One liquid column with initially cylindrical configuration is established by the RANCF fluid element, the position vector of control points and their weights are calculated to achieve the specific initial configuration. A simulation of the cylindrical liquid column collapsing on a plane is implemented to verify the validity of the RANCF fluid element, and numerical results are in good agreement with those obtained in the literature. The convergence of the RANCF fluid element is also checked and proved not to be influenced by mesh size. Finally, the precise description ability of the RANCF fluid element is compared with that of the conventional ANCF fluid element, the former shows a great advantage.
Condensation and Wetting Behavior on Hybrid Superhydrophobic and Superhydrophilic Copper Surfaces
Authors: Wang Hai , Nguyen Quang , Kwon Jae W. , Ma Hongbin 
Published: February 2020

Abstract
A novel hybrid superhydrophobic and superhydrophilic copper surface was fabricated using a lift-off process to integrate the benefits of dropwise and filmwise condensation together. The superhydrophilic surface was comprised of microflower like CuO and nanorod Cu(OH)2 with a diameter in the range of 200–600 nm and the superhydrophobic surface was fabricated by chemical modification with Cytop on the hierarchically structured surface of CuO/Cu(OH)2. Wetting condition effect on the hybrid surface was investigated experimentally with a high-speed camera attached to a microscope and an environmental scanning electrical microscope (ESEM). Out-of-plane droplet jumping motion on superhydrophilic region and gravity effect on the droplet motion were examined. Experiment results showed that effective heat transfer coefficients of hybrid superhydrophobic and superhydrophilic surfaces were improved as compared with those of pure superhydrophobic surface. Comparison results between two hybrid surfaces with 2 and 4 mm pattern pitches indicated that the distance reduction between two neighboring superhydrophilic areas can enhance the condensation performance because short distance can promote the microcondensate coalescence and droplets removal.
Pressure Distribution Across the Handle of an Instrument-Assisted Soft Tissue Mobilization Tool
Authors: Thistle Tori N. , Cannon Andrew , Gallagher John A. 
Published: February 2020

Abstract
Instrument-assisted soft tissue mobilization (IASTM) tools are used during rehabilitative care for treatment of injuries to muscles, tendons, and ligaments. Many studies have quantified treatment application forces between tools and the patient. However, the effect of force on the clinician has not been studied even though research shows that clinicians experience discomfort and fatigue during treatment. This work presents a method to accurately measure the pressure profile between the IASTM tool handle and hand of the clinician. Flexible pressure indicating film was used to measure the pressure magnitude and distribution on the hand. These tests were performed at varying treatment application forces between 15 and 60 N, normal to the treatment surface. The tests were repeated, and forces were compared between 3D-printed designs. The pressure profile on the user was explored by changing aspects of the handle design. Results are analyzed and discussed as an effect of changing handle dimensions. As the diameter of the handle increased, the pressure magnitude decreased while the pressure distribution across the hand increased. Changing the contour of the handle further decreased the magnitude and increased the distribution. This procedure is not specific to the chosen tool and can be repeated for other tools.
Structural Stress Determination at a Hot-Spot
Authors: Han Goeun , Guzey Sukru 
Published: February 2020

Abstract
Stress analysis by a finite element analysis program sometimes causes singularities in hot-spots. In a failure assessment, the structural stress, and membrane and bending stress should be determined in a highly stressed spot (hot-spot). When the structural stress at a hot-spot is disturbed by singularities, the stress result not only diverges, by reducing the element size, but also shows a decreased value compared to nominal stress because the stress is substituted into the von Mises equivalent stress equation. In the three-dimensional (3D) finite element model, it is hard to avoid the singularity problem at hot-spots particularly when it is subjected to loads in three axial directions. For the alternative, this study converts the 3D model into two-dimensional (2D) plane models to remove the singularity and to obtain reasonable structural stress values excluding the peak stress. The structural stress-estimating approaches applied in the 2D model were examined for whether they could avoid the structural stress reduction near the hot-spot with mesh insensitivity. The implemented approaches are stress linearization, single point away method, stress equilibrium, stress extrapolation, and the nodal force method. The results computed by each approach are compared and reconstructed to 3D stress by the Cauchy stress matrix. This study found that the difference in structural stress in 2D was eliminated after the 3D stress reconstruction.
A Multi-Axial Fatigue Limit Prediction Equation for Metallic Materials
Authors: Liu Bowen , Yan Xiangqiao 
Published: February 2020

Abstract
Based on the multi-axial fatigue life prediction model presented recently by the authors, in this note, a fatigue limit prediction equation for metallic materials under multi-axial loading is proposed. In the multi-axial fatigue life prediction model, the wildly used von Mises equivalent stress is taken as an equivalent fatigue mechanical quantity, and the multi-axial fatigue life prediction equation has the invariance of mathematical equation form. By applying the multi-axial fatigue life prediction equation without mean stress effect to fatigue limit case, a simple fatigue limit prediction equation can be obtained. By using a large number of experimental data of metallic materials reported in literature, it has been proven that the fatigue limit prediction equation is not only simple in computation but also high in accuracy.
Chiral Schwinger model with Faddeevian anomaly and its BRST quantization
Authors: Ghosal Sanjib , Rahaman Anisur 
Published: February 2020

AbstractWe consider chiral Schwinger model with Faddeevian anomaly, and carry out the quantization of both the gauge-invariant and non-invariant version of this model has been. Theoretical spectra of this model have been determined both in the Lagrangian and Hamiltonian formulation and a necessary correlation between these two are made. BRST quantization using BFV formalism has been executed which shows spontaneous appearance of Wess–Zumino term during the process of quantization. The gauge invariant version of this model in the extended phase space is found to map onto the physical phase space with the appropriate gauge fixing condition.
Decay properties of P-wave bottom baryons within light-cone sum rules
Authors: Yang Hui-Min , Chen Hua-Xing , Cui Er-Liang , Hosaka Atsushi , Mao Qiang 
Published: February 2020

AbstractWe use the method of light-cone sum rules to study decay properties of P-wave bottom baryons belonging to the SU(3) flavor $$\mathbf {6}_F$$6F representation. In Cui et al. (Phys Rev D 99:094021, 2019) we have studied their mass spectrum and pionic decays, and found that the $$\varSigma _{b}(6097)$$Σb(6097) and $$\varXi _{b}(6227)$$Ξb(6227) can be well interpreted as P-wave bottom baryons of $$J^P = 3/2^-$$JP=3/2-. In this paper we further study their decays into ground-state bottom baryons and vector mesons. We propose to search for a new state $$\varXi _b({5/2}^-)$$Ξb(5/2-), that is the $$J^P = 5/2^-$$JP=5/2- partner state of the $$\varXi _{b}(6227)$$Ξb(6227), in the $$\varXi _b({5/2}^-) \rightarrow \varXi _b^{*}\rho \rightarrow \varXi _b^{*}\pi \pi $$Ξb(5/2-)→Ξb∗ρ→Ξb∗ππ decay process. Its mass is $$12 \pm 5$$12±5 MeV larger than that of the $$\varXi _{b}(6227)$$Ξb(6227).
New coordinates for a simpler canonical derivation of the Hawking effect
Authors: Hossain Golam Mortuza , Singha Chiranjeeb 
Published: February 2020

AbstractIn order to achieve a Hamiltonian-based canonical derivation of the Hawking effect, one usually faces multiple hurdles. Firstly, the spacetime foliation using Schwarzschild time does not lead to hyper-surfaces which are always spacelike. Secondly, the null coordinates which are frequently used in covariant approach, do not lead to a true matter Hamiltonian. Recently, an exact canonical derivation was presented using the so-called near-null coordinates. However, there too one faces the difficulty of having to deal with non-vanishing matter diffeomorphism generator as the spatial decomposition involves a non-zero shift vector. Here we introduce a new set of coordinates which allows one to perform an exact canonical derivation of Hawking effect without having to deal with matter diffeomorphism generator.
Simulation of the magnetocaloric effect by means of theoretical models in Gd3Ni2 and Gd3CoNi systems
Authors: Hsini Mohamed , Boutaleb M. 
Published: February 2020

AbstractIn this work, using a scaling data method based on the mean-field theory (MFT), magnetization isotherms M (H, T) and magnetic entropy change $$ - \Delta S_{M} (T) $$-ΔSM(T) curves have been simulated using MFT combined with the Bean–Rodbell model which verified the second-order phase transition for Gd3Ni2 and Gd3CoNi compounds. Under a low value of magnetic field H, M (T) and $$ - \Delta S_{M} (T) $$-ΔSM(T) curves have been successfully simulated and some magnetocaloric properties have been evaluated using the phenomenological model.
Inhibition of BCL2 Family Members Increases the Efficacy of Copper Chelation in BRAFV600E-Driven Melanoma
Authors: Kim Ye-Jin , Tsang Tiffany , Anderson Grace R. , Posimo Jessica M. , Brady Donita C. 
Published: February 2020

Abstract

The principal unmet need in BRAFV600E-positive melanoma is lack of an adequate therapeutic strategy capable of overcoming resistance to clinically approved targeted therapies against oncogenic BRAF and/or the downstream MEK1/2 kinases. We previously discovered that copper (Cu) is required for MEK1 and MEK2 activity through a direct Cu–MEK1/2 interaction. Repurposing the clinical Cu chelator tetrathiomolybdate (TTM) is supported by efficacy in BRAFV600E-driven melanoma models, due in part to inhibition of MEK1/2 kinase activity. However, the antineoplastic activity of Cu chelators is cytostatic. Here, we performed high-throughput small-molecule screens to identify bioactive compounds that synergize with TTM in BRAFV600E-driven melanoma cells. Genetic perturbation or pharmacologic inhibition of specific members of the BCL2 family of antiapoptotic proteins (BCL-W, BCL-XL, and MCL1) selectively reduced cell viability when combined with a Cu chelator and induced CASPASE-dependent cell death. Further, in BRAFV600E-positive melanoma cells evolved to be resistant to BRAF and/or MEK1/2 inhibitors, combined treatment with TTM and the clinically evaluated BCL2 inhibitor, ABT-263, restored tumor growth suppression and induced apoptosis. These findings further support Cu chelation as a therapeutic strategy to target oncogene-dependent tumor cell growth and survival by enhancing Cu chelator efficacy with chemical inducers of apoptosis, especially in the context of refractory or relapsed BRAFV600E-driven melanoma.

Significance:
This study unveils a novel collateral drug sensitivity elicited by combining copper chelators and BH3 mimetics for treatment of BRAFV600E mutation-positive melanoma.