bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Buckling and Post-buckling Characteristics of Composite Curved Stiffened Fuselage Panel under Hoop Bending load
Authors: Hao C , Nan C Y , Peng Z , Lei L
Published: September 2019

In order to study the buckling, post-buckling and failure modes of composite fuselage structures under circumferential bending loads, innovative four-point bending tests technology was developed and performed on composite curved stiffened fuselage panel (CSFP) specimens with two frame configurations of C-section and Z-section. Meanwhile, the stability engineering analysis and estimation based on plate buckling theory and simplified boundary were carried out, and the finite element (FE) models based on Hashin failure criterion were established to simulate the buckling, post-buckling and failure modes of CSFP specimens. The tests and analysis results show that the buckling modes and failure modes of C-section and Z-section specimens are different under positive bending loads. Specifically, the buckling of C-section specimens firstly occurs in the middle of the frame, then local buckling occurs at both ends of the frame, leading to fracture. For Z-section specimens, only local buckling occurs in the middle of the frame, which directly leads to fracture. By comparing the three methods, the results of FE analysis and engineering calculation are in good agreement with the test results. Among them, the prediction of instability mode and failure mode by FE method is very accurate, and the buckling strain calculated by engineering method can provide a good reference for structural design.
An efficient finite strip procedure for initial post-buckling analysis of composite laminated members
Authors: Ma Pusong , He Bin , Qi Haonan
Published: September 2019

An efficient procedure based on the semi-analytical finite strip method with newly introduced invariant matrices is developed to analyze the initial post-buckling of composite laminated members. The nonlinear strain-displacement equations obtained from the Von-Karman assumption and three plate theories, which are classical thin plate theory, first-order shear deformation plate theory, and high-order shear deformation plate theory can be used to evaluate the initial post-buckling performance of the composite laminated members. According to the principle of the minimum potential energy, the formulations of the finite strip method can be deduced. In order to improve the computational efficiency, the pre-integrated invariant matrices are introduced, which can convert the complicated analytical integral calculation of the stiffness matrix into a relatively simple matrix multiplication calculation. Several benchmark problems are tested based on the proposed method and other conventional methods. The corresponding comparison results show that: (1) the proposed method is proved to be feasible and accurate for those three different theories; (2) compared with the other conventional finite strip methods, the proposed method is much more efficient since it requires the integration of the stiffness matrix only once no matter how many iterations are needed, (3) and the advantage of time-saving is increasingly remarkable as the number of iterations increases.
Fatigue Topology Optimization Based on Global Stress Constraint Method
Authors: Su Peng-Fei , Ye Hong-Ling , Wang Wei-Wei , Sui Yun-Kang
Published: September 2019

In topology optimization design for continuous structure, common mechanical properties considered in optimization model focus on structural strength, stiffness and stability. However, fatigue characteristic of structure is easily ignored, which is one of the main causes of engineering failure. Therefore, it is necessary to consider the fatigue characteristic for the optimization design of the structure. In order to investigate the influence of fatigue on structural topology in optimization design, fatigue life filter function is introduced and then the model and solution method of fatigue topology optimization for continuous structures are proposed based on independent continuous mapping method (ICM). The fatigue topological optimization model is established with structure minimum weight as objective and fatigue life as constraint, and the model is solved by global stress constraint method. The results extend the ICM method and this basic theory provides a new idea for fatigue topology optimization.
Nonlinear dynamics of rotating blades with variable cross-section
Authors: Zhang Wei , Liu Huan , Niu Yan
Published: September 2019

In this chapter, nonlinear dynamic behaviors of the variable cross-section rotating blades are studied. The blade is considered to be a rotating cantilever plate model with variable cross-section. Considering the influence of centrifugal force, variable rotating speed and cross-section warp. In the light of the Hamilton’s principle, the von Karman deformation theory and the third-order shear deformation theory, we can derive the ordinary differential equation by using Galerkin method from the nonlinear partial differential equations. The multiple scales is applied to get the averaged equations with the 1:3 internal resonance of the rotating blades. Using numerical simulation to study the effects of aerodynamic forces and disturbance amplitude of the rotating blades on nonlinear dynamic behaviors. It shows that the rotating blades performs complex nonlinear dynamic behaviors, such as single periodic, chaotic motions, multiple periodic and quasi-periodic.
Numerical prediction of uniaxial tensile properties of 3D braided C/SiC composites
Authors: Hui Xinyu , Wang Haibin , Xu Yingjie , Zhang Weihong
Published: September 2019

This paper is focused on the microstructure modeling and numerical prediction of uniaxial tensile properties of three-dimensional (3D) braided carbon fiber-reinforced silicon carbide (C/SiC) composites. Based on the multiscale characteristics of the fabrication process and component material distribution of 3D braided C/SiC composites, fibre scale and tow scale RVE models were established considering the local periodicity of the microstructure of the composites. Finite element method was applied to predict the elastic properties and strength properties of the fibre scale model, which were then substituted into the tow scale model. The Tsai-Wu failure criterion was employed and the stiffness reduction was conducted in the failed elements according to the different failure modes. The progressive damage process of 3D braided C/SiC composites under uniaxial tensile load was simulated.
Experimental investigation of thermomechanical behaviour of NiTi shape memory alloy under low-velocity impact loading
Authors: Ren Xuanchang , Wang Jun , Xu Yingjie , Zhang Weihong , Zhu Jihong
Published: September 2019

This paper experimentally investigates the thermomechanical behaviour of NiTi shape memory alloy (SMA) under low-velocity impact loading. The phase transformation temperatures of the NiTi material are measured by means of the Differential Scanning Calorimetry (DSC) method. The impact tests are carried out on a drop hammer impact system, wherein force sensor and infrared camera are used to capture the thermomechanical behaviour of NiTi SMA. Several prime material features of SMA, such as superelastic stress-strain response, stress-induced martensitic phase transformation, residual deformation, heat production and energy dissipation, are observed in the drop hammer test of the superelastic NiTi sheet. Considering the impact test is an approximate adiabatic process, the temperature variation on NiTi sheet is highlighted, due to the latent heat and intrinsic dissipation. This temperature variation will affect the mechanical behaviour of SMA, and therefore bring about complex thermomechanical coupling effect in the low-velocity impact test.
Design and Analysis of Multi-layer Integrated Thermal Protection System based on Ceramic Matrix Composite and Titanium Alloy Lattice Sandwich
Authors: Xu Ningxin , Xu Yingjie , Zhang Weihong , Zhu Jihong
Published: September 2019

In order to satisfy the aerodynamic shape requirement of hypersonic vehicles, a curved multi-layer integrated thermal protection system (ITPS) is developed in this paper. The ITPS consists of a ceramic matrix composite layer, a lattice sandwich layer and a glass wool layer. The curved ITPS samples are fabricated. Then experimental test and numerical simulation are carried out respectively to evaluate the heating insulation effect of the ITPS samples. In addition, a series of numerical simulations are conducted to investigate the influences of lattice configuration and gradient layer layout on the heating insulation and load bearing capability of the ITPS.
Modal analysis of the rotating shell structure based on Absolute Nodal Coordinate Formulation
Authors: Yu J C , Wang Q T
Published: September 2019

In recent years, flexible structures composed of cables, plates and shells, such as rotors and solar sails that rotate around a fixed axis have been widely used in aerospace, energy and other industrial fields. Traditional structural dynamics or multi-flexible dynamics modeling methods based on structural small deformation assumptions cannot accurately describe the nonlinear dynamics of flexible structures undergoing large-scale rotation. The Absolute Nodal Coordinate Formulation (ANCF) can accurately describe the flexible multi-body system with both large rigid motions and large deformation. Such flexible structures, while undergoing a wide range of rotational motions, are accompanied by structural vibrations that are excited by unbalanced centrifugal forces, aerodynamic forces, etc., resulting in very complex dynamic behaviors. Therefore, it is of great scientific significance and application value to dynamically model and predict the dynamic response of such flexible structures with a wide range of rotational motions. In this paper, the cylindrical shell element of ANCF proposed by Liu et al. which can realize efficient calculation is briefly introduced. The analytical expressions of elastic force and Jacobin matrix of this shell element are given. Modal analysis of shell structures modeled by ANCF cylindrical shell element and rotating around a fixed axis is studied. The effect of curvature and angular velocities on the modal of shell structures is validated.
Periodic solutions and numerical simulations for composite laminated circular cylindrical shell
Authors: Tian Y Y , Li J , Zhang W , Quan T T
Published: September 2019

Periodic solutions and numerical simulations for a composite laminated circular cylindrical shell under the parametric excitation of temperature are investigated in this paper. By introducing some transformations and defining a Poincaré displacement map, some results, including the existence condition for periodic solutions, least upper bound of the number of periodic solutions and the parameter control conditions, are obtained. To demonstrate the applicability and validity of our theoretical results, the phase portraits of the periodic solutions with different values of the detuning parameter are presented by numerical simulations.
Accurate analysis of steady state response of fully clamped orthotropic functionally graded rectangular plates
Authors: Fan J H , Rong D L , Tong Z Z , Zhao Z , Zhou Z H , Xu X S
Published: September 2019

A Hamiltonian-based method is introduced to find exact solutions for steady state forced vibration of a fully clamped orthotropic functionally graded (FG) rectangular plate. The proposed method has two major steps. Firstly, the steady state response for an FG rectangular plate with Naiver-type boundary conditions is analytically derived by a wave-based symplectic method. Subsequently, exact solutions of the fully clamped FG rectangular plate are obtained by a symplectic superposition technique. The overall procedure is systematic with a clearly defined, step-by-step derivation. The accuracy of the obtained exact solutions is highlighted in comparison with reference data. Numerical results are presented to reveal the effects of the material properties.
A rational analytical approach for buckling analysis of orthotropic double-nanoplate-systems
Authors: Rong D L , Xu C H , Zhang J L , Tong Z Z , Zhou Z H , Xu X S
Published: September 2019

A novel analytical Hamiltonian-based approach is proposed for buckling analysis of orthotropic double-nanoplate-systems (DNPSs) under uniaxially compression embedded in an elastic medium. In the Hamiltonian system, the governing equations for in-phase and out-of-phase buckling are established in a unified form based on Eringen’s nonlocal plate theory. The buckling analysis of the orthotropic DNPS is reduced to an eigenproblem in the symplectic space. Analytical buckling equations and buckling mode shape functions can be obtained by the symplectic eigensolutions and boundary conditions simultaneously. Comparison studies demonstrate the accuracy and efficiency of the proposed method. Key influencing factors which may benefit the design of complex 3D mesostructures are studied in detail. Some new results are given also.
Modelling and simulation for the vibration of a plate with three axes maneuvering
Authors: Zhang Y H , Liu G G , Chen S L
Published: September 2019

In super-maneuvering flight, aircraft often bears high accelerations and high jerks. To ensure the safety of the aircraft, it is necessary to carry out the ground test to simulate the flight loads and the responses of the aircraft. In this paper, mechanical model of the accelerations are established, the distribution characteristic of the accelerations on the plate is explored and the consistency conditions for the centrifugal load and flight load are studied. The dynamic equations of a rectangular thin plate in three-axis centrifugal environment are established by Kane method, and the responses of the plate are calculated. The model established and the results obtained can be used to reflect the responses of the plate in the flight environment.
Sensing characteristic of GPCs induced by sliding of graphene flakes
Authors: Li Zheng , Yang Qing-Sheng
Published: September 2019

The main aim of this paper is to investigate the effect of slide between overlapped graphene flakes on the sensing characteristic of graphene-based polymer composites (GPCs). During deformation process of GPCs, the position of the graphene flakes can be determined by using an affine transformation. The analytical solution is obtained based on the equivalent resistance formulas of series and parallel circuits. Meanwhile, the numerical simulation is also conducted through the finite element method (FEM). In addition, the consistence between the analytical solution and numerical result are proved by a simple model consisted of two-layer graphene flakes. The result shows that the gauge factor (GF) of the sensor is related to both the initial resistance and the length of the graphene flakes: the GF of the sensor decreases with the increase of the initial resistance, while the effect of the length of graphene flakes is less. Moreover, the pre-stretched GPCs have a larger sensing range which can improve the usability of the sensor.
Study on Drag Torque Characteristics of Corrugated Joint for Spacesuit under Human-Induced Loads
Authors: Wang L Y , Zhou S M , Shang K , Li D K
Published: September 2019

The mobility of spacesuit joints is the key factor affecting the ability of the lower-torso space service, and the drag torque of joint is an important indicator which represents the mobility of joint. Drag torque is affected by many factors, such as contact with garment, gas pressure and materials of spacesuit, which cause difficulties in theoretical calculation. A finite element simulation on drag torque characteristics of corrugated joint of spacesuit with human body is carried out. And a detailed finite element model is established which reflects the characteristics of fabric material and the actual structure of corrugated joint. Based on this model, the dynamic simulation of joint rotation in two ways of external driving and human body driving is carried out. The cause of drag torque is analyzed. Then the influence of spacing and arc length of bellows on characteristics of drag torque is studied. The results show that the sources of drag torque during rotation are the structural elastic deformation and the work to compress gas. The drag torque of joint which is in the way of human body driving is greater than by external driving, which is because the elastic deformation and work to compress gas of the former are both larger than the latter. And methods, reducing the spacing and increasing the arc length of bellows, could reduce the drag torque of joint.
Fracture analysis of cracks terminating at the interface of elastic-piezoelectric bimaterials
Authors: Yu X , Yang Z T , Xu C H , Xing Y , Zhou Z H , Xu X S
Published: September 2019

In this paper, the fracture behaviors of a piezoelectric-elastic bimaterial with cracks terminating at the interface are investigated by a symplectic approach. In the Hamiltonian system, the Hamiltonian forms of governing equations is derived by the Hamiltonian variational principle and a total unknown vector consisted of generalized displacements and stresses. The interface fracture problem is reduced into a symplectic eigenproblem which can be directly solved by the method of separation of variables. Thus, the total unknown vector is expanded in terms of symplectic eigenfunctions. The unknown coefficients of the symplectic series can be determined from the continuity conditions at the interface and outer boundary conditions. Consequently, exact solutions for the singular electro-elastic fields and explicit expression of electric/elastic intensity factors are obtained simultaneously. Results indicate that the electro-elastic singularities and intensity factors only depend on the first few terms of symplectic eigenfunctions with non-zero eigenvalues. Numerical examples are presented to show the effects of key influencing factors on the singularity orders and intensity factors of such interface cracks. Some new results are given also.
Lithium-related medication problems on nonpsychiatric inpatient medical units
Authors: Alastanos Jennifer N , Potter Teresa G , Crouse Ericka L
Published: September 2019

Purpose

Results of a study of medication-related problems (MRPs) associated with lithium use on nonpsychiatric inpatient medical units are reported.

Methods

In a single-center, retrospective study, the records of all patients hospitalized over a 21-month period who received lithium or had a documented serum lithium concentration during hospitalization were evaluated. The primary objective was to identify patient-specific factors associated with lithium MRPs on nonpsychiatric inpatient medical units. Secondary objectives included characterization of lithium MRPs. Identified MRP occurrences were further evaluated to determine if an intervention was necessary to resolve the MRP and whether or not an intervention was made.

Results

A total of 150 patients were included in the study sample. One or more lithium MRPs were identified in 85% of the patients, with a total of 255 lithium MRPs identified. None of the patient-specific factors analyzed were significantly associated with MRP occurrence. Of the 128 patients in whom a lithium MRP occurred, 92.2% (n = 118) were judged to be appropriate candidates for interventions as defined per the study definitions; among those 118 patients, such interventions were documented for only 40.7% (n = 48).

Conclusion

Lithium MRPs were found to have occurred frequently on nonpsychiatric inpatient medical units at 1 hospital. Laboratory test– related MRPs and drug–drug interactions were the most commonly identified types of MRPs. Interventions to address MRPs were not made in the majority of patients; however, interventions were more frequently made when psychiatry consultation was involved.
Graph embedding on biomedical networks: methods, applications and evaluations
Authors: Yue Xiang , Wang Zhen , Huang Jingong , Parthasarathy Srinivasan , Moosavinasab Soheil , Huang Yungui , Lin Simon M , Zhang Wen , Zhang Ping , Sun Huan
Published: September 2019

Motivation

Graph embedding learning that aims to automatically learn low-dimensional node representations, has drawn increasing attention in recent years. To date, most recent graph embedding methods are evaluated on social and information networks and are not comprehensively studied on biomedical networks under systematic experiments and analyses. On the other hand, for a variety of biomedical network analysis tasks, traditional techniques such as matrix factorization (which can be seen as a type of graph embedding methods) have shown promising results, and hence there is a need to systematically evaluate the more recent graph embedding methods (e.g. random walk-based and neural network-based) in terms of their usability and potential to further the state-of-the-art.

Results

We select 11 representative graph embedding methods and conduct a systematic comparison on 3 important biomedical link prediction tasks: drug-disease association (DDA) prediction, drug–drug interaction (DDI) prediction, protein–protein interaction (PPI) prediction; and 2 node classification tasks: medical term semantic type classification, protein function prediction. Our experimental results demonstrate that the recent graph embedding methods achieve promising results and deserve more attention in the future biomedical graph analysis. Compared with three state-of-the-art methods for DDAs, DDIs and protein function predictions, the recent graph embedding methods achieve competitive performance without using any biological features and the learned embeddings can be treated as complementary representations for the biological features. By summarizing the experimental results, we provide general guidelines for properly selecting graph embedding methods and setting their hyper-parameters for different biomedical tasks.

Availability and implementation

As part of our contributions in the paper, we develop an easy-to-use Python package with detailed instructions, BioNEV, available at: https://github.com/xiangyue9607/BioNEV, including all source code and datasets, to facilitate studying various graph embedding methods on biomedical tasks.

Supplementary information

Supplementary data are available at Bioinformatics online.
Scalable inference for crossed random effects models
Authors: Papaspiliopoulos O , Roberts G O , Zanella G
Published: September 2019

We develop methodology and complexity theory for Markov chain Monte Carlo algorithms used in inference for crossed random effects models in modern analysis of variance. We consider a plain Gibbs sampler and propose a simple modification, referred to as a collapsed Gibbs sampler. Under some balancedness conditions on the data designs and assuming that precision hyperparameters are known, we demonstrate that the plain Gibbs sampler is not scalable, in the sense that its complexity is worse than proportional to the number of parameters and data, but the collapsed Gibbs sampler is scalable. In simulated and real datasets we show that the explicit convergence rates predicted by our theory closely match the computable, but nonexplicit rates in cases where the design assumptions are violated. We also show empirically that the collapsed Gibbs sampler extended to sample precision hyperparameters significantly outperforms alternative state-of-the-art algorithms.
Phenotypic assays in yeast and zebrafish reveal drugs that rescue ATP13A2 deficiency
Authors: Heins-Marroquin Ursula , Jung Paul P , Cordero-Maldonado Maria Lorena , Crawford Alexander D , Linster Carole L
Published: September 2019

Mutations in ATP13A2 (PARK9) are causally linked to the rare neurodegenerative disorders Kufor-Rakeb syndrome, hereditary spastic paraplegia and neuronal ceroid lipofuscinosis. This suggests that ATP13A2, a lysosomal cation-transporting ATPase, plays a crucial role in neuronal cells. The heterogeneity of the clinical spectrum of ATP13A2-associated disorders is not yet well understood and currently, these diseases remain without effective treatment. Interestingly, ATP13A2 is widely conserved among eukaryotes, and the yeast model for ATP13A2 deficiency was the first to indicate a role in heavy metal homeostasis, which was later confirmed in human cells. In this study, we show that the deletion of YPK9 (the yeast orthologue of ATP13A2) in Saccharomyces cerevisiae leads to growth impairment in the presence of Zn2+, Mn2+, Co2+ and Ni2+, with the strongest phenotype being observed in the presence of zinc. Using the ypk9Δ mutant, we developed a high-throughput growth rescue screen based on the Zn2+ sensitivity phenotype. Screening of two libraries of Food and Drug Administration-approved drugs identified 11 compounds that rescued growth. Subsequently, we generated a zebrafish model for ATP13A2 deficiency and found that both partial and complete loss of atp13a2 function led to increased sensitivity to Mn2+. Based on this phenotype, we confirmed two of the drugs found in the yeast screen to also exert a rescue effect in zebrafish—N-acetylcysteine, a potent antioxidant, and furaltadone, a nitrofuran antibiotic. This study further supports that combining the high-throughput screening capacity of yeast with rapid in vivo drug testing in zebrafish can represent an efficient drug repurposing strategy in the context of rare inherited disorders involving conserved genes. This work also deepens the understanding of the role of ATP13A2 in heavy metal detoxification and provides a new in vivo model for investigating ATP13A2 deficiency.
The Development of a Screening Tool to Identify and Classify Nonadherence in Inflammatory Bowel Disease
Authors: Zand Aria , Nguyen Audrey , Stokes Zack , van Deen Welmoed , Reynolds Courtney , Dimitrova Magdalena , Khandadash Ariela , Dvorsky Miriam , Sauk Jenny , Esrailian Eric , Hommes Daniel
Published: September 2019

Background

Medication nonadherence is a challenge in chronic disease management. Tools that can both determine adherence levels and analyze patient-specific reasons for nonadherence are lacking.

Methods

Our tool was developed using 23 patient-reported items and its predictive performance was compared with the most widely used instrument in the literature.

Results

One hundred thirty-three IBD patients were included, 44 (33%) were nonadherent and 89 (67%) were adherent. Our screening question, with 87% sensitivity and 64% specificity, was followed by a 9-item survey for patients qualified as nonadherent.

Conclusions

Quantifying reasons for nonadherence can lead to more effective and personalized interventions for nonadherent patients.
Antibody-mediated rejection 16 years post-cardiac transplantation: a case report of an uncommon late presentation in a middle-aged woman
Authors: Miller Charles , Arkun Knarik , DeNofrio David , Sabe Marwa
Published: September 2019

Background 

Very late antibody-mediated rejection (AMR) in heart transplant patients (over 10 years post-transplant) is very rare. It is associated with high mortality, graft dysfunction, and fulminant coronary artery vasculopathy (CAV) and should remain in the differential for patients presenting with late graft dysfunction.

Case summary 

A 57-year-old woman 16 years of post-heart transplant with a previously unremarkable post-transplant course including protocol driven biopsies showing no rejection and a recent unremarkable screening nuclear stress test presented to our institution with clinical heart failure. Echocardiogram revealed graft dysfunction and endomyocardial biopsy showed no signs of cellular rejection, but evidence of AMR. The patient was treated with steroid and immunotherapy with clinical improvement but suffered several infectious complications and renal dysfunction requiring haemodialysis related to her immunotherapy treatment. Despite aggressive AMR management, donor-specific antibodies and symptoms persisted and CAV progressed.

Discussion 

This case illustrates the poor diagnostic yield of non-invasive testing for AMR, and highlights importance to clinicians of considering AMR even if the patient over 10 years post-transplant when the diagnosis is rare.
Acute fluctuating neurological deficits after pulmonary vein isolation: unmasking a rare complication due to spontaneous spinal subdural bleeding: a case report
Authors: Cioffi Giacomo Maria , Regoli François , Conte Giulio , Auricchio Angelo
Published: September 2019

Background

Pulmonary vein isolation (PVI) is becoming the therapy of choice for symptomatic paroxysmal drug-refractory atrial fibrillation (AF). The most frequently reported complications are vascular complications (1.4%). Bleeding complications of the central nervous system have rarely been described. We report a case of spontaneous spinal bleed after PVI.

Case summary

A 68-year-old woman with a 2-year history of highly symptomatic paroxysmal AF (EHRA 3) was referred for a PVI redo procedure. A high-density mapping showed pulmonary vein reconnection of all pulmonary veins successfully isolated by radiofrequency ablation. During the entire procedure, the patient had sinus rhythm with an ACT around 300 s. No intraprocedural and peri-procedural complications occurred. Four hours after haemostasis, the anticoagulation clotting time (ACT) was 110 s and rivaroxaban (20 mg) was reinitiated. In the following hours, the patient developed fluctuating neurological lower limb symptoms. A lumbar magnetic resonance imaging showed a subdural spinal haematic collection with an associated epidural component from L3 to S2 exerting compression over the dural sheath. A conservative treatment approach was adopted with progressive recovery of sensorial and motor deficits. After 5 months, the patient still presented residual lower limb motor deficits necessitating the support of a walking stick.

Discussion

We describe the first case of a spontaneous spinal bleeding following PVI. Given the gradual diffusion of PVI to treat AF in more clinically complex patients with a larger range of comorbidities, particular consideration should be given to seek predisposing bleeding factors in order to assess the risk for neurological complications.
Percutaneous left atrial appendage closure in a patient with haemophilia and atrial fibrillation: a case report
Authors: Güray Ümit , Korkmaz Ahmet , Gürsoy Havva Tuğba , Elalmış Özgül Uçar
Published: September 2019

Background 

Atrial fibrillation (AF) is the most common cardiac arrhythmia and is a major cause of embolic stroke. In patients with hereditary bleeding disorders such as haemophilia, management of AF particularly anticoagulation can be quite challenging. Left atrial appendage (LAA) closure is an emerging option in AF patients who are not eligible for oral anticoagulation therapy because of contraindications or high bleeding risk.

Case summary 

A 67-year-old man with permanent AF and haemophilia was referred for further evaluation of our cardiology clinic by his primary haematologist. The CHA2DS2-VASc score was estimated to be 3 and the HAS-BLED score was 3. Due to high risk of bleeding, we decided to perform percutaneous LAA closure instead of oral anticoagulation. Pre-procedural cardiac computerized tomography angiography and transoesophageal echocardiography were performed for measurements of LAA dimensions and exclude LAA thrombus. Percutaneous LAA occlusion was performed using a 28-mm AmplatzerTM AmuletTM device. The final result was excellent without significant residual leak, pericardial effusion, and embolic complication. Clopidogrel 75 mg/day and aspirin 81 mg/day for 1 month with adequate FVIII prophylaxis and then only aspirin 81 mg/day for 2 months were recommended. No antiplatelet was given after 3 months. The patient did not report any thrombotic or haemorrhagic adverse events and there were no complications related to implanted device after 1 year of follow-up.

Discussion 

In patients with hereditary bleeding disorders such as haemophilia, management of AF particularly anticoagulation can be quite challenging. In this report, we present a case of percutaneous LAA occlusion using AmplatzerTM AmuletTM device in a patient who has haemophilia and permanent AF. LAA closure has the potential to be more cost effective as compared to oral anticoagulation therapy due to lesser necessity of clotting factor infusion.
Handel’s choruses of ‘praise and thanksgiving after victory’ and Non nobis Domine
Authors: Kim Minji
Published: September 2019

Handel highlights several climactic moments in his works with choruses composed of closely related cantus firmus themes and contrapuntal settings. Parallels can be traced through individual sections of some of the key compositions that define his career in England: ‘Oh Lord, in thee have I trusted’, from the Utrecht Te Deum (1713), ‘Blessed be God’, from Let God arise (1717–18/1726), ‘I will sing’, from Israel in Egypt (1738), and ‘Hallelujah’ from Messiah (1741). The common purpose of giving thanks and praise to God for military victory further links these choruses. While several different melodic sources have been suggested for the cantus firmus subjects thus far, the affinity of all four of Handel’s themes to the incipit of a very well-known canon, Non nobis Domine, invites an exploration of its possible citation. The customary practice of singing the canon or reciting its psalm text at celebratory moments, modelling the psalmist’s deflection of all the honour of his accomplishments to God, makes its reference in Handel’s works highly appropriate. Understanding Handel’s multiple reuse of his choral setting in the context of this tradition deepens the relevance of his music as well as our perspective on his self-borrowing.
Historical microbiology – using a Van Musschenbroek microscope
Authors: Quint Koen D , Robertson Lesley A
Published: September 2019

A single-lensed microscope made by the Van Musschenbroek workshops between 1690 and 1750 has been examined experimentally, and the method of use established. The results were compared with those obtained with facsimile van Leeuwenhoek microscopes. As might be expected, each microscope had its stronger and weaker points.
Disparities in Acute Pain Treatment by Cognitive Status in Older Adults With Hip Fracture
Authors: Chang Andrew K , Edwards Robert R , Morrison R Sean , Argoff Charles , Ata Ashar , Holt Christian , Bijur Polly E
Published: September 2019

Background

We examined the disparities in emergency department (ED) pain treatment based on cognitive status in older adults with an acute hip fracture.

Methods

Observational study in an academic ED in the Bronx, New York. One hundred forty-four adults aged 65 years and older with acute hip fracture were administered the Telephone Interview for Cognitive Status (TICS) while in the ED. The primary outcome was receipt of any parenteral analgesic. The risk factor of interest was cognitive impairment (TICS ≤ 25). Secondary outcomes included receipt of any opioid, receipt of any analgesic, total dose of analgesics in intravenous morphine equivalent units (MEQ), and time to receiving first analgesic.

Results

Of the 87 (60%) study patients who were cognitively impaired, 60% received a parenteral analgesic compared to 79% of the 57 cognitively unimpaired patients (RR 0.76 [95% CI 0.61, 0.94]). The effect of cognitive impairment on receiving any opioids (RR: 0.81, 95% CI 0.67, 0.98) and any analgesic (RR: 0.85; 95% CI: 0.71, 1.01) was similar. The median analgesic dose in cognitively impaired patients was significantly lower than in cognitively unimpaired patients (4 MEQ vs 8 MEQ, p = .003).

Conclusion

Among older adults presenting to the ED with acute hip fracture, cognitive impairment was independently associated with lower likelihood of receiving analgesia and lower amount of opioid analgesia.
Illuminating Meanings of Thriving for Persons Living in Nursing Homes
Authors: Baxter Rebecca , Sandman Per-Olof , Björk Sabine , Lood Qarin , Edvardsson David
Published: September 2019

Background and Objectives

Thriving has been described as a multidimensional concept that can be used to explore place-related well-being; however, there has been limited research into the meaning of thriving in aged care. This study aimed to illuminate meanings of thriving as narrated by persons living in nursing homes.

Research Design and Methods

Narrative interviews were conducted with 21 persons residing in a rural Australian nursing home. The interviews were audio-recorded, transcribed, and interpreted using a phenomenological hermeneutic approach.

Results

Meanings of thriving could be understood as: Striving toward acceptance of being in a nursing home while maintaining a positive outlook; Feeling supported and cared for while maintaining a sense of independence; Balancing opportunities for solitude and company while living with others; and, Feeling a sense of home while residing in an institutional environment. The meanings of thriving, as presented through the interpretive lens of Gaston Bachelard’s “Poetics of Space,” encompassed having access to literal, metaphorical, and symbolic doors, as well as having the freedom to open, close, and use these doors however the person wishes.

Discussion

Exploring meanings of thriving in nursing homes could contribute towards understanding and implementing positive life-world constructs in research and practice. These findings could be used to inform and enhance person-centered care practices by maximizing opportunities for persons residing in nursing homes to have options and choices, and the agency to make decisions where possible, in relation to their everyday care and living environment.
Study of the quantitative effect of the depositional layering tendency of inclusions on the elastic anisotropy of shale based on two-step homogenization
Authors: Zhang Yao , Xie Lingzhi , Zhao Peng , He Bo
Published: September 2019

Shale anisotropy is related to numerous small-scale factors, including the transverse isotropy of clay particles, clay shape aspect ratio, shape preference orientation, pore/crack alignment, infilling materials and the depositional distribution and shape aspect ratio of inclusion minerals. Although a depositional layering tendency of inclusions due to sedimentation has been observed, few studies of its effect on shale anisotropy have been carried out. In this work, the effect of the depositional layering tendency of inclusions on the elastic anisotropy of shale is quantitatively analysed along with three other factors (i.e. the inclusion fraction, the orientation dependence of clay elastic properties, where ‘oriented’ refers to transverse isotropic clay and ‘non-oriented’ refers to isotropic clay, and the clay elastic moduli) based on analysis of variance and the two-step homogenization of shale by assuming that shale is a composite of clay and inclusions. The results show that the depositional layering tendency of inclusions of this type of shale has a relatively limited effect on the elastic anisotropy of intact shale, while the orientation dependence of the elastic properties of the clay has a predominant influence.
Utilization of Diagnostic Imaging and Ionizing Radiation Exposure—Has the Tide Already Turned?
Authors: Zundler Sebastian
Published: September 2019

Inflammatory bowel diseases require repetitive abdominal imaging for diagnosis, follow-up, or management of complications. This editorial comments on the large incident-based case–control study on utilization of diagnostic imaging and ionizing radiation exposure by Nguyen and colleagues published in this issue.
Cerebral Vasculitis in Crohn's Disease: Always a Complication of Inflammatory Bowel Disease or Tumor Necrosis Factor–Alpha Inhibition?
Authors: Moser Tobias , Bubel Nele E , Machegger Lukas , Pikija Slaven , Sellner Johann
Published: September 2019

Cerebral vasculitis may be a complication of Crohn’s disease (CD) or a side-effect of therapies with biologics including tumor-necrosis factor-alpha antibodies. Here, we report a case of progressive brainstem syndrome and cranial polyneuritis in a patient with CD who had been treated with infliximab. We identified Lyme neuroborreliosis (LNB) as the cause of cerebral vasculitis and ischemic stroke and observed a favorable course following antibiotic treatment. Our case highlights the need for extensive search of causes of cerebral vasculitis in patients with CD and treatment with biologics.
Utilization of pop-up satellite archival transmitting tags to evaluate thorny skate (Amblyraja radiata) discard mortality in the Gulf of Maine groundfish bottom trawl fishery
Authors: Knotek Ryan , Kneebone Jeff , Sulikowski James , Curtis Tobey , Jurek Joseph , Mandelman John
Published: September 2019

Thorny skate (Amblyraja radiata) remain one of the most overfished species in the Gulf of Maine (GOM) despite being designated as a prohibited (zero-possession, mandatory release) species by the New England Fishery Management Council in 2003. To better understand the extent to which discard mortality (DM) occurring after incidental capture in the GOM groundfish bottom trawl fishery may be impeding recovery, 75 individuals (55–94 cm total length, TL) were tagged with pop-up satellite archival transmitting (PSAT) tags and monitored for up to 28 days following capture under representative commercial trawl fishing practices. Data recovered from 61 PSAT-tagged skate were analysed with a longitudinal survival analysis to estimate DM and identify influential capture-related variables. DM rate was a function of TL, with larger skates (>70 cm; DM = 16.5%) experiencing lower mortality than smaller conspecifics (55–70 cm; DM = 24.5%). From our results, we estimate annual thorny skate DM in the GOM groundfish bottom trawl fishery to be 79.2 ± 0.2 mt, which accounts for <1% of the existing stock biomass in the GOM (8400 mt). This study confirms that thorny skate are relatively resilient to bottom trawl fishing practices in the GOM, and suggests that other sources of mortality may be impeding population recovery.
Drug Abuse-Related Neuroinflammation in Human Postmortem Brains: An Immunohistochemical Approach
Authors: Moretti Matteo , Belli Giacomo , Morini Luca , Monti Maria Cristina , Osculati Antonio Marco Maria , Visonà Silvia Damiana
Published: September 2019

The aim of the study was to investigate blood-brain barrier alterations, neuroinflammation, and glial responses in drug abusers. Five immunohistochemical markers (CD3, zonula occludens-1 [ZO-1], intracellular adhesion molecule 1 [ICAM-1], vascular cell adhesion molecule [VCAM-1], and glial fibrillary acidic protein [GFAP]) were assessed on postmortem brain samples collected from drug abusers who died from acute intoxication of cocaine, heroin, or a combination of both, compared with controls. CD3 and ICAM-1 immunopositivity were significantly stronger in drug abusers than in controls. VCAM-1 immunopositivity was similar across drug abuser and control groups. In heroin abusers, significantly lower ZO-1 immunopositivity was observed relative to controls. GFAP positivity did not show significant differences between groups, but its distribution within the brain did differ. Both cocaine and heroin abuse promoted neuroinflammation, increasing expression of ICAM-1 and recruiting CD3+ lymphocytes. Heroin affected the molecular integrity of tight junctions, as reflected by reduced ZO-1 expression. The outcomes of the present study are, overall, consistent with prior available evidence, which is almost exclusively from studies conducted in vitro or in animal models. These findings provide important information about the downstream consequences of neuroinflammation in drug abusers and may help to inform the development of potential therapeutic targets.
The Berkeley sample of Type II supernovae: BVRI light curves and spectroscopy of 55 SNe II
Authors: de Jaeger T , Zheng W , Stahl B E , Filippenko A V , Brink T G , Bigley A , Blanchard K , Blanchard P K , Bradley J , Cargill S K , Casper C , Cenko S B , Channa S , Choi B Y , Clubb K I , Cobb B E , Cohen D , de Kouchkovsky M , Ellison M , Falcon E , Fox O D , Fuller K , Ganeshalingam M , Gould C , Graham M L , Halevi G , Hayakawa K T , Hestenes J , Hyland M P , Jeffers B , Joubert N , Kandrashoff M T , Kelly P L , Kim H , Kim M , Kumar S , Leonard E J , Li G Z , Lowe T B , Lu P , Mason M , McAllister K J , Mauerhan J C , Modjaz M , Molloy J , Perley D A , Pina K , Poznanski D , Ross T W , Shivvers I , Silverman J M , Soler C , Stegman S , Taylor S , Tang K , Wilkins A , Wang Xiaofeng , Wang Xianggao , Yuk H , Yunus S , Zhang K D
Published: September 2019

In this work, BVRI light curves of 55 Type II supernovae (SNe II) from the Lick Observatory Supernova Search programme obtained with the Katzman Automatic Imaging Telescope and the 1 m Nickel telescope from 2006 to 2018 are presented. Additionally, more than 150 spectra gathered with the 3 m Shane telescope are published. We conduct an analyse of the peak absolute magnitudes, decline rates, and time durations of different phases of the light and colour curves. Typically, our light curves are sampled with a median cadence of 5.5 d for a total of 5093 photometric points. In average, V-band plateau declines with a rate of 1.29 mag (100 d)−1, which is consistent with previously published samples. For each band, the plateau slope correlates with the plateau length and the absolute peak magnitude: SNe II with steeper decline have shorter plateau duration and are brighter. A time-evolution analysis of spectral lines in term of velocities and pseudo-equivalent widths is also presented in this paper. Our spectroscopic sample ranges between 1 and 200 d post-explosion and has a median ejecta expansion velocity at 50 d post-explosion of 6500 km s−1 (H α line) and a standard dispersion of 2000 km s−1. Nebular spectra are in good agreement with theoretical models using a progenitor star having a mass <16M⊙. All the data are available to the community and will help to understand SN II diversity better, and therefore to improve their utility as cosmological distance indicators.
Risk Management Failures
Authors: Bouvard Matthieu , Lee Samuel
Published: September 2019

We model risk management as information acquisition that delays trading decisions. In markets with preemptive competition, this can lead to a race to the bottom, where prioritizing trade execution over risk management is optimal for each firm, but collectively inefficient. As time competition intensifies, mean trading profit supplants risk concerns as the main driver of risk management quality, causing risk misallocation to rise with trading speed and volume. This pathology of risk management failure—the trio of time-consuming risk assessment, preemptive competition, and boom markets—has distinctive regulatory implications.

Authors have furnished an Internet Appendix, which is available on the Oxford University Press Web site next to the link to the final published paper online.