bluuebunny/crossref_metadata_2025 huggingface dataset:
The context dependent effects of host competence, competition, and the pathogen transmission mode on disease prevalence
Authors: Cortez Michael H. , Duffy Meghan A.
Published: February 2020

Biodiversity in communities is changing globally, including the gain and loss of host species in host-pathogen communities. Increased host diversity can cause infection prevalence in a focal host to increase (amplification) or decrease (dilution). However, it is unclear what general rules govern the context dependent effects, in part because theories for pathogens with different transmission modes have developed largely independently. Using a two-host model, we explore how the pathogen transmission mode and characteristics of a second host (disease competence and competitive ability) influence disease prevalence in a focal host. Our work shows how the theories for pathogens with environmental transmission, density-dependent direct transmission, and frequency-dependent direct transmission can be unified. Our work also identifies general rules about how host and pathogen characteristics affect amplification/dilution. For example, higher competence hosts promote amplification, unless they are strong interspecific competitors; strong interspecific competitors promote dilution, unless they are large sources of new infections; and dilution occurs under frequency-dependent direct transmission more than density-dependent direct transmission, unless interspecific host competition is sufficiently strong. Our work helps explain how the characteristics of the pathogen and a second host affect disease prevalence in a focal host.
The architecture of metabolism maximizes biosynthetic diversity in the largest class of fungi
Authors: Gluck-Thaler Emile , Haridas Sajeet , Binder Manfred , Grigoriev Igor V. , Crous Pedro W. , Spatafora Joseph W. , Bushley Kathryn , Slot Jason C.
Published: February 2020

Background

Ecological diversity in fungi is largely defined by metabolic traits, including the ability to produce secondary or “specialized” metabolites (SMs) that mediate interactions with other organisms. Fungal SM pathways are frequently encoded in biosynthetic gene clusters (BGCs), which facilitate the identification and characterization of metabolic pathways. Variation in BGC composition reflects the diversity of their SM products. Recent studies have documented surprising diversity of BGC repertoires among isolates of the same fungal species, yet little is known about how this population-level variation is inherited across macroevolutionary timescales.

Results

Here, we applied a novel linkage-based algorithm to reveal previously unexplored dimensions of diversity in BGC composition, distribution, and repertoire across 101 species of Dothideomycetes, which are considered to be the most phylogenetically diverse class of fungi and are known to produce many SMs. We predicted both complementary and overlapping sets of clustered genes compared with existing methods and identified novel gene pairs that associate with known secondary metabolite genes. We found that variation in BGC repertoires is due to non-overlapping BGC combinations and that several BGCs have biased ecological distributions, consistent with niche-specific selection. We observed that total BGC diversity scales linearly with increasing repertoire size, suggesting that secondary metabolites have little structural redundancy in individual fungi.

Conclusions

We project that there is substantial unsampled BGC diversity across specific families of Dothideomycetes, which will provide a roadmap for future sampling efforts. Our approach and findings lend new insight into how BGC diversity is generated and maintained across an entire fungal taxonomic class.
Effects of dopamine agonist treatment on resting-state network connectivity in Parkinson’s disease
Authors: Cole David M. , Mohammadi Bahram , Milenkova Maria , Kollewe Katja , Schrader Christoph , Samii Amir , Dengler Reinhard , Münte Thomas F. , Beckmann Christian F.
Published: February 2020

Dopamine agonist (DA) medications commonly used to treat, or ‘normalise’, motor symptoms of Parkinson’s disease (PD) may lead to cognitive-neuropsychiatric side effects, such as increased impulsivity in decision-making. Subject-dependent variation in the neural response to dopamine modulation within cortico-basal ganglia circuitry is thought to play a key role in these latter, non-motor DA effects. This neuroimaging study combined resting-state functional magnetic resonance imaging (fMRI) with DA modification in patients with idiopathic PD, investigating whether brain ‘resting-state network’ (RSN) functional connectivity metrics identify disease-relevant effects of dopamine on systems-level neural processing. By comparing patients both ‘On’ and ‘Off’ their DA medications with age-matched, un-medicated healthy control subjects (HCs), we identified multiple non-normalising DA effects on frontal and basal ganglia RSN cortico-subcortical connectivity patterns in PD. Only a single isolated, potentially ‘normalising’, DA effect on RSN connectivity in sensori-motor systems was observed, within cerebro-cerebellar neurocircuitry. Impulsivity in reward-based decision-making was positively correlated with ventral striatal connectivity within basal ganglia circuitry in HCs, but not in PD patients. Overall, we provide brain systems-level evidence for anomalous DA effects in PD on large-scale networks supporting cognition and motivated behaviour. Moreover, findings suggest that dysfunctional striatal and basal ganglia signalling patterns in PD are compensated for by increased recruitment of other cortico-subcortical and cerebro-cerebellar systems.
Cytoprotection by a naturally occurring variant of ATP5G1 in Arctic ground squirrels
Authors: Singhal Neel S. , Bai Meirong , Lee Evan M. , Luo Shuo , Cook Kayleigh R. , Ma Dengke K.
Published: February 2020

Many organisms, from anaerobic bacteria to hibernating ground squirrels, have evolved mechanisms to tolerate severe hypoxia or ischemia. In particular, the arctic ground squirrel (AGS) has been shown to be highly resilient to ischemic and reperfusion injuries, demonstrating an ability to withstand metabolic stress under hibernation conditions. Although physiological adaptations are critical to ischemic tolerance in AGS, little is known about cellular mechanisms underlying intrinsic AGS cell tolerance to metabolic stressors. Through cell survival-based cDNA expression screens and comparative genomics, we have discovered that in AGS, a cytoprotective variant of ATP5G1 helps confer improved mitochondrial metabolism and cell resilience to metabolic stress.ATP5G1encodes a proton-transporting subunit of the mitochondrial ATP synthase complex. Ectopic expression in mouse cells and CRISPR/Cas9 base editing of the endogenous AGS locus revealed causal roles of one AGS-specific amino acid substitution (leucine-32) in mediating the cytoprotective effects of AGS ATP5G1. We provide evidence that AGS ATP5G1 promotes cell resilience to stress by modulating mitochondrial morphological change and metabolic functions. Thus, our results identify a naturally occurring variant of ATP5G1 from a mammalian hibernator that causally contributes to intrinsic cytoprotection against metabolic stresses.
The novel coronavirus 2019 (2019-nCoV) uses the SARS-coronavirus receptor ACE2 and the cellular protease TMPRSS2 for entry into target cells
Authors: Hoffmann Markus , Kleine-Weber Hannah , Krüger Nadine , Müller Marcel , Drosten Christian , Pöhlmann Stefan
Published: February 2020

The emergence of a novel, highly pathogenic coronavirus, 2019-nCoV, in China, and its rapid national and international spread pose a global health emergency. Coronaviruses use their spike proteins to select and enter target cells and insights into nCoV-2019 spike (S)-driven entry might facilitate assessment of pandemic potential and reveal therapeutic targets. Here, we demonstrate that 2019-nCoV-S uses the SARS-coronavirus receptor, ACE2, for entry and the cellular protease TMPRSS2 for 2019-nCoV-S priming. A TMPRSS2 inhibitor blocked entry and might constitute a treatment option. Finally, we show that the serum form a convalescent SARS patient neutralized 2019-nCoV-S-driven entry. Our results reveal important commonalities between 2019-nCoV and SARS-coronavirus infection, which might translate into similar transmissibility and disease pathogenesis. Moreover, they identify a target for antiviral intervention.

One sentence summary

The novel 2019 coronavirus and the SARS-coronavirus share central biological properties which can guide risk assessment and intervention.
Online analysis of microendoscopic 1-photon calcium imaging data streams
Authors: Friedrich Johannes , Giovannucci Andrea , Pnevmatikakis Eftychios A.
Published: February 2020

In-vivo calcium imaging through microendoscopic lenses enables imaging of neuronal populations deep within the brains of freely moving animals. Previously, a constrained matrix factorization approach (CNMF-E) has been suggested to extract single-neuronal activity from microendoscopic data. However, this approach relies on offline batch processing of the entire video data and is demanding both in terms of computing and memory requirements. These drawbacks prevent its applicability to the analysis of large datasets and closed-loop experimental settings. Here we address both issues by introducing two different online algorithms for extracting neuronal activity from streaming microendoscopic data. Our first algorithm presents an online adaptation of the CNMF-E algorithm, which dramatically reduces its memory and computation requirements. Our second algorithm proposes a convolution-based background model for microendoscopic data that enables even faster (real time) processing on GPU hardware. Our approach is modular and can be combined with existing online motion artifact correction and activity deconvolution methods to provide a highly scalable pipeline for microendoscopic data analysis. We apply our algorithms on two previously published typical experimental datasets and show that they yield similar high-quality results as the popular offline approach, but outperform it with regard to computing time and memory requirements.

Author summary

Calcium imaging methods enable researchers to measure the activity of genetically-targeted large-scale neuronal subpopulations. Whereas previous methods required the specimen to be stable, e.g. anesthetized or head-fixed, new brain imaging techniques using microendoscopic lenses and miniaturized microscopes have enabled deep brain imaging in freely moving mice.

However, the very large background fluctuations, the inevitable movements and distortions of imaging field, and the extensive spatial overlaps of fluorescent signals complicate the goal of efficiently extracting accurate estimates of neural activity from the observed video data. Further, current activity extraction methods are computationally expensive due to the complex background model and are typically applied to imaging data after the experiment is complete. Moreover, in some scenarios it is necessary to perform experiments in real-time and closed-loop – analyzing data on-the-fly to guide the next experimental steps or to control feedback –, and this calls for new methods for accurate real-time processing. Here we address both issues by adapting a popular extraction method to operate online and extend it to utilize GPU hardware that enables real time processing. Our algorithms yield similar high-quality results as the original offline approach, but outperform it with regard to computing time and memory requirements. Our results enable faster and scalable analysis, and open the door to new closed-loop experiments in deep brain areas and on freely-moving preparations.
A Disinhibitory Circuit for Contextual Modulation in Primary Visual Cortex
Authors: Keller Andreas J. , Dipoppa Mario , Roth Morgane M. , Caudill Matthew S. , Ingrosso Alessandro , Miller Kenneth D. , Scanziani Massimo
Published: February 2020

Context guides perception by influencing the saliency of sensory stimuli. Accordingly, in visual cortex, responses to a stimulus are modulated by context, the visual scene surrounding the stimulus. Responses are suppressed when stimulus and surround are similar but not when they differ. The mechanisms that remove suppression when stimulus and surround differ remain unclear. Here we use optical recordings, manipulations, and computational modelling to show that a disinhibitory circuit consisting of vasoactive-intestinal-peptide-expressing (VIP) and somatostatin-expressing (SOM) inhibitory neurons modulates responses in mouse visual cortex depending on the similarity between stimulus and surround. When the stimulus and the surround are similar, VIP neurons are inactive and SOM neurons suppress excitatory neurons. However, when the stimulus and the surround differ, VIP neurons are active, thereby inhibiting SOM neurons and relieving excitatory neurons from suppression. We have identified a canonical cortical disinhibitory circuit which contributes to contextual modulation and may regulate perceptual saliency.
Axonal ER Ca2+Release Enhances Miniature, but Reduces Activity-Dependent Glutamate Release in a Huntington Disease Model
Authors: Mackay James P. , Smith-Dijak Amy I. , Koch Ellen T. , Zhang Peng , Fung Evan , Nassrallah Wissam B. , Buren Caodu , Schmidt Mandi , Hayden Michael R. , Raymond Lynn A.
Published: February 2020

Action potential-independent (miniature) neurotransmission occurs at all chemical synapses, but remains poorly understood, particularly in pathological contexts. Spontaneous release of Ca2+from the axonal endoplasmic reticulum (ER) is thought to facilitated miniature neurotransmission, and aberrant ER Ca2+handling is notably implicated in the progression of Huntington’s disease (HD) and other neurodegenerative diseases. Here, we report elevated glutamate-mediated miniature synaptic event frequencies in YAC128 (HD-model) cortical neurons, which pharmacological experiments suggest is mediated by enhanced spontaneous ER Ca2+release. Calcium imaging using an axon-localized sensor revealed slow action potential (AP)-independent axonal Ca2+waves, which were more common in YAC128 cortical neurons. Conversely, spontaneous axonal ER Ca2+release was associated with reduced AP-dependent axonal Ca2+events and consequent glutamate release. Together, our results suggest spontaneous release of axonal ER Ca2+stores oppositely regulates activity-dependent and -independent neurotransmitter release in HD, with potential implications for the fidelity and plasticity of cortical excitatory signaling.
Haplotype Diversity and Sequence Heterogeneity of Human Telomeres
Authors: Grigorev Kirill , Foox Jonathan , Bezdan Daniela , Butler Daniel , Luxton Jared J. , Reed Jake , Meydan Cem , Bailey Susan M. , Mason Christopher E.
Published: February 2020

Telomeres are regions of repetitive nucleotide sequences capping the ends of eukaryotic chromosomes that protect against deterioration, whose lengths can be correlated with age and disease risk factors. Given their length and repetitive nature, telomeric regions are not easily reconstructed from short read sequencing, making telomere sequence resolution a very costly and generally intractable problem. Recently, long-read sequencing, with read lengths measuring in hundreds of Kbp, has made it possible to routinely read into telomeric regions and inspect their structure. Here, we describe a framework for extracting telomeric reads from single-molecule sequencing experiments, describing their sequence variation and motifs, and for haplotype inference. We find that long telomeric stretches can be accurately captured with long-read sequencing, observe extensive sequence heterogeneity of human telomeres, discover and localize non-canonical motifs (both previously reported as well as novel), and report the first motif composition maps of human telomeric diplotypes on a multi-Kbp scale.
Evaluation of Professional Ballet Dancers Body Posture During Barre Movements
Authors: Patterson R. M. , Hershberger N. , Balyakina E. , Capell W. , Mirochnitchenko A. , Surve S.
Published: February 2020

Ballet dancers have finite careers due to the demands placed upon their bodies throughout years of training, study, and performance. The average age a dancer retires is 34 due to persistent stress on their joints and injuries due to mechanical overload or overuse. Proper form is crucial to prevent injury. The aim of this study was to establish benchmarks for normal movement patterns among professional dancers. Ten professional ballerinas were studied. Reflective markers were placed on the pelvis, left and right anterior superior iliac spine (ASIS), and posterior iliac spine (PSIS) to evaluate motion during Barre movements: plié, grand battement, and développé. Pelvis flexion/extension, mediolateral rotation, and torsion were analyzed. These motions test different skills. The plié is a controlled coordinated motion using both legs. The grand battement and développé both require leg extension, one with a quick motion that creates momentum and one using controlled motion that requires strength. Each requires core and pelvis stability to perform accurately and with less injury. Dancers' motions were consistent. Maximum pelvis range of motion for the plié, grand battement, and développé were 8.0, 42, and 50 deg, respectively. This represents usable benchmarks with which other dancers may be compared, for example, those who are at different levels of training, injured, predisposed to injury, or recovering from injury. Early recognition of pathologic movement patterns could benefit professional and amateur dancers by helping to prevent injuries, and potentially improve the quality and length of their careers.
Acoustic Cell Separation Based on Density and Mechanical Properties
Authors: Xie Yuliang , Mao Zhangming , Bachman Hunter , Li Peng , Zhang Peiran , Ren Liqiang , Wu Mengxi , Huang Tony Jun
Published: February 2020

Density and mechanical properties (e.g., compressibility or bulk modulus) are important cellular biophysical markers. As such, developing a method to separate cells directly based on these properties can benefit various applications including biological research, diagnosis, prognosis, and therapeutics. As a potential solution, surface acoustic wave (SAW)-based cell separation has demonstrated advantages in terms of biocompatibility and compact device size. However, most SAW-reliant cell separations are achieved using an entangled effect of density, various mechanical properties, and size. In this work, we demonstrate SAW-based separation of cells/particles based on their density and compressibility, irrespective of their sizes, by manipulating the acoustic properties of the fluidic medium. Using our platform, SAW-based separation is achieved by varying the dimensions of the microfluidic channels, the wavelengths of acoustic signals, and the properties of the fluid media. Our method was applied to separate paraformaldehyde-treated and fresh Hela cells based on differences in mechanical properties; a recovery rate of 85% for fixed cells was achieved. It was also applied to separate red blood cells (RBCs) and white blood cells (WBCs) which have different densities. A recovery rate of 80.5% for WBCs was achieved.
Historical Review of Combined Experimental and Computational Approaches for Investigating Annulus Fibrosus Mechanics
Authors: Zhou Minhao , Werbner Benjamin , O'Connell Grace
Published: February 2020

Intervertebral disc research has sought to develop a deeper understanding of spine biomechanics, the complex relationship between disc health and back pain, and the mechanisms of spinal injury and repair. To do so, many researchers have focused on characterizing tissue-level properties of the disc, where the roles of tissue subcomponents can be more systematically investigated. Unfortunately, experimental challenges often limit the ability to measure important disc tissue- and subtissue-level behaviors, including fiber–matrix interactions, transient nutrient and electrolyte transport, and damage propagation. Numerous theoretical and numerical modeling frameworks have been introduced to explain, complement, guide, and optimize experimental research efforts. The synergy of experimental and computational work has significantly advanced the field, and these two aspects have continued to develop independently and jointly. Meanwhile, the relationship between experimental and computational work has become increasingly complex and interdependent. This has made it difficult to interpret and compare results between experimental and computational studies, as well as between solely computational studies. This paper seeks to explore issues of model translatability, robustness, and efficient study design, and to propose and motivate potential future directions for experimental, computational, and combined tissue-level investigations of the intervertebral disc.
Sloshing in Regular Polygonal Basins—Frequencies, Modes, and Tileability
Authors: Wang C. Y.
Published: February 2020

The classical theory of small amplitude shallow water waves is applied to regular polygonal basins. The natural frequencies of the basins are related to the eigenvalues of the Helmholtz equation. Exact solutions are presented for triangular, square, and circular basins while pentagonal, hexagonal, and octagonal basins are solved, for the first time, by an efficient Ritz method. The first five eigenvalues of each basin are tabulated and the corresponding mode shapes are discussed. Tileability conditions are presented. Some modes (eigenmodes) can be tiled into larger domains.
Machining Response and Damage Evolution of Amorphous Carbon Coated Tools in High-Speed Micromilling of Ti–6Al–4V
Authors: Mittal Rinku K. , Kulkarni Salil S. , Barshilia Harish , Singh Ramesh
Published: February 2020

Micromilling process is widely used to create complex 3D miniature products due to its flexibility and its ability to process difficult-to-cut material like Titanium alloys. High rotational speeds are used to overcome the limited flexural stiffness of the tool but the cutting zone temperatures rise due to the high rotational speeds. In addition to this, friction between the tool workpiece and tool chip also plays a major role in the temperature rise. The friction and temperature affect the cutting forces, tool life and stability of the process. To reduce the friction and heat generation, nanostructured solid lubricant coatings can be used. This study is focused on characterizing the effect of amorphous carbon (WC/a-C) coating on the micromachining response during high-speed micromilling of Ti–6Al–4V. A decrease in cutting forces for coated tools is observed for lower feed. A comprehensive tool coating damage assessment has been done in terms of debonding area on flank and rake faces. An increase in debonding area has been observed with lengths of cut but at a feed/flute of 4 μm, tool breakage occurs after a machining length of 60 mm.
Machining Simulation in Focused Ion Beam Sputtering
Authors: Matsumura Takashi , Ogasawara Ryosuke
Published: February 2020

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

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

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

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

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

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

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

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

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

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

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

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.
Blockade of EGFR improves responsiveness to PD-1 blockade in
EGFR
-mutated non–small cell lung cancer
Authors: Sugiyama Eri , Togashi Yosuke , Takeuchi Yoshiko , Shinya Sayoko , Tada Yasuko , Kataoka Keisuke , Tane Kenta , Sato Eiichi , Ishii Genichiro , Goto Koichi , Shintani Yasushi , Okumura Meinoshin , Tsuboi Masahiro , Nishikawa Hiroyoshi
Published: February 2020

EGFR inhibitor erlotinib synergizes with anti–PD-1 in a mouse model of lung adenocarcinoma.
Redox potential tuning in bio-relevant heterocycles via (anti)aromaticity modulated H-bonding (AMHB)
Authors: Kakeshpour Tayeb , Van Wiemeersch Adam , Jackson James E.
Published: February 2020

Hydrogen bonds are arguably the most important non-covalent interactions in chemistry and biology, and their strength and directionality have been elegantly exploited in the rational design of complex structures. We recently noted that the variable responses of cyclic π-systems upon H-bond formation reciprocally lead to modulations of the H-bonds’ strengths, a phenomenon that we dubbed (anti)aromaticity-modulated hydrogen bonding (AMHB) [J. Am. Chem. Soc. 2016, 138, 3427–3432]. Species that switch from aromatic to antiaromatic or vice versa upon changing π-electron counts should be oppositely stabilized by the AMHB effects, so their redox potentials should be significantly “tuned” by H-bond formation. Herein, using quantum chemical simulations, we explore the effects of these H-bond induced π-electron polarizations on the redox potentials of (anti)aromatic heterocycles. The systems chosen for this study have embedded amide groups and amidine moieties capable of forming two-point H-bonds in their cyclic π-systems. Thus, as the 4-electron and 6-electron π-systems in redox-capable monocycles (e.g., quinones) can be differentially stabilized, their redox potentials can be modulated by H-bond formation by as much as 6 kcal/mol (258 mV for one electron transfer). In fused rings, the connectivity patterns are as important as the π-electron counts. Extending these ideas to flavin, a biologically relevant case, we find that H-bonding patterns like those found in its crystals can vary its redox potential by up to 1.3 kcal/mol.
A standardized protocol for reporting methods when using drones for wildlife research
Authors: Barnas Andrew F. , Chabot Dominque , Hodgson Amanda J. , Johnston David W. , Bird David M. , Ellis-Felege Susan N.
Published: February 2020

Drones are increasingly popular tools for wildlife research, but it is important that the use of these tools does not overshadow reporting of methodological details required for evaluation of study designs. The diversity in drone platforms, sensors, and applications necessitates the reporting of specific details for replication, but there is little guidance available on how to detail drone use in peer-reviewed articles. Here, we present a standardized protocol to assist researchers in reporting of their drone use in wildlife research. The protocol is delivered in six sections: Project Overview; Drone System and Operation Details; Payload, Sensor, and Data Collection; Field Operation Details; Data Post-Processing; and Permits, Regulations, Training, and Logistics. Each section outlines the details that should be included, along with justifications for their inclusion. To facilitate ease of use, we have provided two example protocols, retroactively produced for published drone-based studies by the authors of this protocol. Our hopes are that the current version of this protocol should assist with the communication, dissemination, and adoption of drone technology for wildlife research and management.
Chiral Schwinger model with Faddeevian anomaly and its BRST quantization
Authors: Ghosal Sanjib , Rahaman Anisur
Published: February 2020

We 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

We 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

In 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

In 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.