bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pelvic Leiomyosarcoma With Splenic Metastasis and Response Assessment by 18F-FDG PET/CT
Authors: Yadav Divya , Kumar Rakesh , Rastogi Sameer , Shamim Shamim Ahmed 
Published: May 2020

Abstract
The pelvis is a rare site for the origin of soft tissue sarcomas, and leiomyosarcoma remains the most common soft tissue sarcoma arising in the pelvis. Pelvic leiomyosarcomas are frequently aggressive tumors, and metastatic recurrence rates are high, with the lung, peritoneum, bone, and liver being the most frequent sites. We describe the findings of serial 18F-FDG PET/CT in a 53-year-old woman having pelvic leiomyosarcoma with uncommon site of metastasis, emphasizing the role of 18F-FDG PET/CT in response assessment.
Post Contusion Breast Hematoma Mimicking Malignancy on FDG PET/CT
Authors: Levin Daniel , Lantsberg Sophie , Giladi Maia Rosenthal , Kazap Dina Ezroh , Hod Nir 
Published: May 2020

Abstract
A 32-year-old woman was treated for breast carcinoma. Posttreatment FDG PET/CT scan revealed complete response, but in the contralateral breast, unexpected incidental intense FDG uptake was seen with a differential diagnosis of both malignant and benign causes. Medical history revealed recent breast contusion. The lesion was further evaluated by mammogram and ultrasound, which were compatible with deep breast bruise. Histopathology showed no malignancy. Subsequent FDG PET/CT study showed breast uptake normalization. This case shows that postcontusion breast hematoma can cause a potential pitfall mimicking breast malignancy on FDG PET/CT.
Variations in Volume and Costs of Inpatient Admissions for Female Pelvic Reconstructive Procedures Across the United States
Authors: Wang Rui , Tulikangas Paul , Hacker Michele R. 
Published: May 2020

Objectives
We aim to describe the volume and cost of female pelvic reconstructive surgeries across the United States and evaluate the relationship between volume and cost of inpatient care for these surgeries.

Methods
Medicare Severity Diagnosis Related Group was used to identify admissions for female pelvic reconstructive procedures and aggregated at the state and census region levels using the 2016 Inpatient Medicare Provider Utilization and Payment Data. Total hospital charges were converted to cost using the cost-to-charge ratios for each state. For context and comparison with another benign gynecologic procedure, we replicated the analysis for benign uterine and adnexal surgeries.

Results
We identified 2133 patients admitted for female pelvic reconstructive procedures. Across all states, the average cost was US $11,857, and the average number of procedures per 100,000 Medicare beneficiaries was 4.4. The Northeast had the lowest cost, and the West had the highest. The regression model showed that, for each additional admission per 100,000 Medicare beneficiaries, the cost of inpatient care decreased (US $549, P = 0.04). In comparison, we identified 8340 admissions for benign uterine and adnexal surgeries and found a minimal, nonsignificant decrease in cost for each additional admission.

Conclusions
There are variations in the volume and cost of admissions for female pelvic reconstructive surgeries across the United States. We identified that an inverse association between volume and cost for female pelvic reconstructive surgery was not seen in benign uterine and adnexal surgeries.
On the thermodynamical restrictions in isothermal deformations of fractional Burgers model
Authors: Atanacković Teodor M. , Janev Marko , Pilipović Stevan 
Published: May 2020

We investigate, in the distributional setting, the restrictions on the constitutive equation for a fractional Burgers model of viscoelastic fluid that follow from the weak form of the entropy inequality under isothermal conditions. The results are generalized, from the Burgers model, to an arbitrary class of linear constitutive equations with fractional derivatives. Our results show that the restrictions obtained here on the coefficients of constitutive equations are weaker when compared with the restrictions obtained by Bagley–Torvik method. We show the precise relation between restrictions derived here and those derived by Bagley–Torvik. We deal with the creep test, for the case when Bagley–Torvik conditions are violated, and new conditions obtained in this work are satisfied. The results show a qualitative difference in the form of creep function.
This article is part of the theme issue ‘Advanced materials modelling via fractional calculus: challenges and perspectives’.
Fractional-order heat conduction models from generalized Boltzmann transport equation
Authors: Li Shu-Nan , Cao Bing-Yang 
Published: May 2020

The relationship between fractional-order heat conduction models and Boltzmann transport equations (BTEs) lacks a detailed investigation. In this paper, the continuity, constitutive and governing equations of heat conduction are derived based on fractional-order phonon BTEs. The underlying microscopic regimes of the generalized Cattaneo equation are thereafter presented. The effective thermal conductivityκeffconverges in the subdiffusive regime and diverges in the superdiffusive regime. A connection between the divergence and mean-square displacement 〈|Δx|2〉 ∼ tγis established, namely,κeff ∼ tγ−1, which coincides with the linear response theory. Entropic concepts, including the entropy density, entropy flux and entropy production rate, are studied likewise. Two non-trivial behaviours are observed, including the fractional-order expression of entropy flux and initial effects on the entropy production rate. In contrast with the continuous time random walk model, the results involve the non-classical continuity equations and entropic concepts.This article is part of the theme issue ‘Advanced materials modelling via fractional calculus: challenges and perspectives’.
Effect of adsorption, radioactive decay and fractal structure of matrix on solute transport in fracture
Authors: Chugunov Vladimir , Fomin Sergei 
Published: May 2020

Reservoir contamination by various contaminants including radioactive elements is an actual environmental problem for all developed countries. Analysis of mass transport in a complex environment shows that the conventional diffusion equation based on Fick's Law fails to model the anomalous character of the diffusive mass transport observed in the field and laboratory experiments. These complex processes can be modelled by non-local advection–diffusion equations with temporal and spatial fractional derivatives. In the present paper, fractional differential equations are used for modelling the transport of radioactive materials in a fracture surrounded by the porous matrix of fractal structure. A new form of fractional differential equation for modelling migration of the radioactive contaminant in the fracture is derived and justified. Solutions of particular boundary value problems for this equation were found by application of the Laplace transform. Through the use of fractional derivatives, the model accounts for contaminant exchange between fracture and surrounding porous matrix of fractal geometry. For the case of an arbitrary time-dependent source of radioactive contamination located at the inlet of the fracture, the exact solutions for solute concentration in the fracture and surrounding porous medium are obtained. Using the concept of a short memory, an approximate solution of the problem of radioactive contaminant transport along the fracture surrounded by the fractal type porous medium is also obtained and compared with the exact solution.
This article is part of the theme issue ‘Advanced materials modelling via fractional calculus: challenges and perspectives’.
Mathematical modelling with experimental validation of viscoelastic properties in non-Newtonian fluids
Authors: Ionescu C. M. , Birs I. R. , Copot D. , Muresan C. I. , Caponetto R. 
Published: May 2020

The paper proposes a mathematical framework for the use of fractional-order impedance models to capture fluid mechanics properties in frequency-domain experimental datasets. An overview of non-Newtonian (NN) fluid classification is given as to motivate the use of fractional-order models as natural solutions to capture fluid dynamics. Four classes of fluids are tested: oil, sugar, detergent and liquid soap. Three nonlinear identification methods are used to fit the model: nonlinear least squares, genetic algorithms and particle swarm optimization. The model identification results obtained from experimental datasets suggest the proposed model is useful to characterize various degree of viscoelasticity in NN fluids. The advantage of the proposed model is that it is compact, while capturing the fluid properties and can be identified in real-time for further use in prediction or control applications.This article is part of the theme issue ‘Advanced materials modelling via fractional calculus: challenges and perspectives’.
Variable-order particle dynamics: formulation and application to the simulation of edge dislocations
Authors: Patnaik Sansit , Semperlotti Fabio 
Published: May 2020

This study presents the application of variable-order (VO) fractional operators to modelling the dynamics of edge dislocations under the effect of a static state of shear stress. More specifically, a particle dynamic approach is used to simulate the microscopic structure of a material where the constitutive atoms or molecules are modelled via discrete masses and their interaction via inter-particle forces. VO operators are introduced in the formulation in order to capture the complex linear-to-nonlinear dynamic transitions following the translation of dislocations as well as the creation and annihilation of bonds between particles. Remarkably, the motion of the dislocation does not require anya prioriassumption in terms of either possible trajectory or sections of the model that could undergo the nonlinear transition associated with the creation and annihilation of bonds. The model only requires the definition of the initial location of the dislocations. Results will show that the VO formulation is fully evolutionary and capable of capturing both the sliding and the coalescence of edge dislocations by simply exploiting the instantaneous response of the system and the state of stress.This article is part of the theme issue ‘Advanced materials modelling via fractional calculus: challenges and perspectives’.
Application of fractional calculus methods to viscoelastic behaviours of solid propellants
Authors: Fang Changqing , Shen Xiaoyin , He Kuai , Yin Chao , Li Shasha , Chen Xiaolong , Sun Huiyu 
Published: May 2020

A three-branch viscoelastic model based on fractional derivatives is proposed for the viscoelastic behaviours of solid propellants. The simulation results show a satisfactory agreement with the stress relaxation modulus and complex modulus of solid propellants. As a comparison, the static modulus is also characterized by traditional viscoelastic model with integer-order derivatives. Results show that the application of the fractional derivatives to the viscoelastic constitutive model can effectively reduce the number of the required parameters while giving an accurate prediction of viscoelastic behaviours of solid propellants. Moreover, a simple and effective direct search method based on simulated annealing and Powell's mothed is proposed for the data fitting.
This article is part of the theme issue ‘Advanced materials modelling via fractional calculus: challenges and perspectives'.
Fractional-order modelling of epoxy resin
Authors: Tenreiro Machado J. A. , Lopes António M. , de Camposinhos Rui 
Published: May 2020

This paper describes epoxy resins by means of electrical impedance spectroscopy (EIS) and the mathematical tool of fractional calculus (FC). Two stages are considered: first, the EIS is used for testing the samples and, second, the measured data are approximated using integer and fractional order models. The FC-based modelling describes the epoxy resins using a small number of parameters that reflect their main characteristics. The EIS data gathered for the epoxies samples are compared with those of different adhesives and sealants by means of a hierarchical clustering algorithm that unravels the relationships between the distinct materials.This article is part of the theme issue ‘Advanced materials modelling via fractional calculus: challenges and perspectives’.
Fractional-order nonlinear hereditariness of tendons and ligaments of the human knee
Authors: Bologna E. , Di Paola M. , Dayal K. , Deseri L. , Zingales M. 
Published: May 2020

In this paper the authors introduce a nonlinear model of fractional-order hereditariness used to capture experimental data obtained on human tendons of the knee. Creep and relaxation data on fibrous tissues have been obtained and fitted with logarithmic relations that correspond to power-laws with nonlinear dependence of the coefficients. The use of a proper nonlinear transform allows one to use Boltzmann superposition in the transformed variables yielding a fractional-order model for the nonlinear material hereditariness. The fundamental relations among the nonlinear creep and relaxation functions have been established, and the results from the equivalence relations have been contrasted with measures obtained from the experimental data. Numerical experiments introducing polynomial and harmonic stress and strain histories have been reported to assess the provided equivalence relations.
This article is part of the theme issue ‘Advanced materials modelling via fractional calculus: challenges and perspectives’.
A novel approach to nonlinear variable-order fractional viscoelasticity
Authors: Di Paola M. , Alotta G. , Burlon A. , Failla G. 
Published: May 2020

This paper addresses nonlinear viscoelastic behaviour of fractional systems with variable time-dependent fractional order. In this case, the main challenge is that the Boltzmann linear superposition principle, i.e. the theoretical basis on which linear viscoelastic fractional operators are formulated, does not apply in standard form because the fractional order is not constant with time. Moving from this consideration, the paper proposes a novel approach where the system response is derived by a consistent application of the Boltzmann principle to an equivalent system, built at every time instant based on the fractional order at that instant and the response at all the previous ones. The approach is readily implementable in numerical form, to calculate either stress or strain responses of any fractional system where fractional order may change with time.
This article is part of the theme issue ‘Advanced materials modelling via fractional calculus: challenges and perspectives’.
Multi-term time fractional diffusion equations and novel parameter estimation techniques for chloride ions sub-diffusion in reinforced concrete
Authors: Chen Ruige , Wei Xiaoli , Liu Fawang , Anh Vo V. 
Published: May 2020

In this paper, searching for a better chloride ions sub-diffusion system, a multi-term time-fractional derivative diffusion model is proposed for the description of the time-dependent chloride ions penetration in reinforced concrete structures exposed to chloride environments. We prove the stability and convergence of the model. We use the modified grid approximation method (MGAM) to estimate the fractional orders and chloride ions diffusion coefficients in the reinforced concrete for the multi-term time fractional diffusion system. And then to verify the efficiency and accuracy of the proposed methods in dealing with the fractional inverse problem, two numerical examples with real data are investigated. Meanwhile, we use two methods of fixed chloride ions diffusion coefficient and variable diffusion coefficient with diffusion depth to simulate chloride ions sub-diffusion system. The result shows that with the new fractional orders and parameters, our multi-term fractional order chloride ions sub-diffusion system is capable of providing numerical results that agree better with the real data than other models. On the other hand, it is also noticed from the numerical solution of the chloride ions sub-diffusion system that setting the variable diffusion coefficient with diffusion depth is more reasonable. And it is also found that chloride ions diffusion coefficients in reinforced concrete should be decreased with diffusion depth which is completely consistent with the theory. In addition, the model can be used to predict the chloride profiles with a time-dependent property.This article is part of the theme issue ‘Advanced materials modelling via fractional calculus: challenges and perspectives’.
Impact force and moment problems on random mass density fields with fractal and Hurst effects
Authors: Zhang Xian , Ostoja-Starzewski Martin 
Published: May 2020

This paper reports the application of cellular automata to study the dynamic responses of Lamb-type problems for a tangential point load and a concentrated moment applied on the free surface of a half-plane. The medium is homogeneous, isotropic and linear elastic while having a random mass density field with fractal and Hurst characteristics. Both Cauchy and Dagum random field models are used to capture these effects. First, the cellular automata approach is tested on progressively finer meshes to verify the code against the continuum elastodynamic solution in a homogeneous continuum. Then, the sensitivity of wave propagation on random fields is assessed for a wide range of fractal and Hurst parameters. Overall, the mean response amplitude is lowered by the mass density field’s randomness, while the Hurst parameter (especially, for
β
< 0.2) is found to have a stronger influence than the fractal dimension on the response. The resulting Rayleigh wave is modified more than the pressure wave for the same random field parameters. Additionally, comparisons with previously studied Lamb-type problems under normal in-plane and anti-plane loadings are given.

This article is part of the theme issue ‘Advanced materials modelling via fractional calculus: challenges and perspectives’.
Advanced materials modelling via fractional calculus: challenges and perspectives
Authors: Failla Giuseppe , Zingales Massimiliano 
Published: May 2020

Fractional calculus is now a well-established tool in engineering science, with very promising applications in materials modelling. Indeed, several studies have shown that fractional operators can successfully describe complex long-memory and multiscale phenomena in materials, which can hardly be captured by standard mathematical approaches as, for instance, classical differential calculus. Furthermore, fractional calculus has recently proved to be an excellent framework for modelling non-conventional fractal and non-local media, opening valuable prospects on future engineered materials. The theme issue gathers cutting-edge theoretical, computational and experimental studies on advanced materials modelling via fractional calculus, with a focus on complex phenomena and non-conventional media.
This article is part of the theme issue ‘Advanced materials modelling via fractional calculus: challenges and perspectives’.
Characterisation of Acute Kidney Injury in Critically Ill Patients with Severe Coronavirus Disease-2019 (COVID-19)
Authors: Rubin Sébastien , Orieux Arthur , Prevel Renaud , Garric Antoine , Bats Marie-Lise , Dabernat Sandrine , Camou Fabrice , Guisset Olivier , Issa Nahema , Mourissoux Gaelle , Dewitte Antoine , Joannes-Boyau Olivier , Fleureau Catherine , Rozé Hadrien , Carrié Cédric , Petit Laurent , Clouzeau Benjamin , Sazio Charline , Bui Hoang-Nam , Pillet Odile , Rigothier Claire , Vargas Frederic , Combe Christian , Gruson Didier , Boyer Alexandre 
Published: May 2020

AbstractBackgroundCOVID-19-associated acute kidney injury frequency, severity and characterisation in critically ill patients has not been reported.MethodsSingle-center cohort performed from March 3, 2020, to April 14, 2020 in 4 intensive care units in Bordeaux University Hospital, France. All patients with COVID19 and pulmonary severity criteria were included. AKI was defined using KDIGO criteria. A systematic urinary analysis was performed. The incidence, severity, clinical presentation, biological characterisation (transient vs. persistent acute kidney injury; proteinuria, hematuria and glycosuria), and short-term outcomes was evaluated.Results71 patients were included, with basal serum creatinine of 69 ± 21 µmol/L. At admission, AKI was present in 8/71 (11%) patients. Median follow-up was 17 [12–23] days. AKI developed in a total of 57/71 (80%) patients with 35% Stage 1, 35% Stage 2, and 30% Stage 3 acute kidney injury; 10/57 (18%) required renal replacement therapy. Transient AKI was present in only 4/55 (7%) patients and persistent AKI was observed in 51/55 (93%). Patients with persistent AKI developed a median urine protein/creatinine of 82 [54–140] (mg/mmol) with an albuminuria/proteinuria ratio of 0.23 ± 20 indicating predominant tubulo-interstitial injury. Only 2 (4%) patients had glycosuria. At Day 7 onset of after AKI, six (11%) patients remained dependent on renal replacement therapy, nine (16%) had SCr > 200 µmol/L, and four (7%) died. Day 7 and day 14 renal recovery occurred in 28% and 52 % respectively.ConclusionCOVID-19-associated AKI is frequent, persistent severe and characterised by an almost exclusive tubulo-interstitial injury without glycosuria.
Higher BMI, but not obesity-related genetic polymorphisms, correlates with reduced structural connectivity of the reward network
Authors: Beyer Frauke , Zhang Rui , Scholz Markus , Wirkner Kerstin , Loeffler Markus , Stumvoll Michael , Villringer Arno , Witte A. Veronica 
Published: May 2020

BackgroundObesity is of complex origin, involving genetic and neurobehavioral factors. Most consistently, polymorphisms in the fat-and-obesity associated gene (FTO) may increase the risk for developing obesity by modulating dopaminergic signaling in the brain. Dopamine-dependent behaviors, such as reward processing, are crucial for eating behavior and are altered in obesity. Yet, few studies have investigated the association of obesity, related genetic variants and structural connectivity of the dopaminergic reward network.MethodsWe analyzed 378 participants (age range: 20 – 59 years, BMI range: 17 – 38 kg/m2) of the LIFE-Adult Study. Genotyping for the single nucleotid polymorphisms rs1558902 (FTO) and rs1800497 (near dopamine D2 receptor) was performed on a micro-array. Structural connectivity of the reward network was derived from diffusion-weighted magnetic resonance imaging at 3 Tesla using deterministic tractography of Freesurfer-de-rived regions of interest. Using graph metrics, we extracted summary measures of clustering coefficient and connectivity strength between frontal and striatal brain regions, normalized for global connectivity. We applied linear regression models to test the association of BMI, risk alleles of both variants and reward network connectivity.ResultsHigher BMI was significantly associated with reduced connectivity strength for fractional anisotropy (β= −0.0011, 95%-C.I. [−0.0019, −0.0003], p= 0.0062) and number of streamlines (β = −0.0026, 95%-C.I.:[−0.004,−0.0009], p= 0.0024), but not clustering coefficient. Strongest associations were found for right accumbens, right lateral orbitofrontal cortex and left putamen. As expected, the polymorphism rs1558902 in FTO was associated with higher BMI (F=7.9, p<0.001). None of the genetic variants was associated with reward network structural connectivity.ConclusionsHere, we provide evidence that higher BMI correlates with reduced reward network structural connectivity. This result is in line with previous findings of obesity-related decline in white matter microstructure. We did not find any association of variants in FTO or near DRD2 receptor and reward network structural connectivity, indicating that the genetic influence of these variants is small or non-existent. Future research should investigate the behavioral implications of structural connectivity differences in the fronto-striatal network and incorporate larger sample sizes with longitudinal designs in order to gain further insight into the genetic determinants of obesity in the brain.