bluuebunny/crossref_metadata_2025 huggingface dataset:
Developing a UK registry to investigate the role of cardiovascular magnetic resonance (CMR) in patients who activate the primary percutaneous coronary intervention (PPCI) pathway: a multicentre, feasibility study linking routinely collected electronic patient data
Authors: Brierley Rachel C , Pufulete Maria , Harris Jessica , Bucciarelli-Ducci Chiara , Greenwood John P , Dorman Stephen , Anderson Richard , Rogers Chris A , Reeves Barnaby C
Published: March 2018

Objectives

To determine whether it is feasible to set up a national registry, linking routinely collected data from hospital information systems (HIS), to investigate the role of cardiovascular magnetic resonance (CMR) in patients who activate the primary percutaneous coronary intervention (PPCI) pathway.

Design

Feasibility prospective cohort study, to establish whether: (1) consent can be implemented; (2) data linkage and extraction from multiple HIS can be achieved for >90% of consented patients; (3) local data can be successfully linked with hospital episode data (Hospital Episode Statistics, HES; Patient Episode Database for Wales, PEDW) for >90% of consented patients and (4) the proportion of patients activating the PPCI pathway who get a CMR scan is ≥10% in hospitals with dedicated CMR facilities.

Participants

Patients from four 24/7 PPCI hospitals in England and Wales (two with and two without a dedicated CMR facility) who activated the PPCI pathway and underwent an emergency coronary angiogram.

Results

Consent was successfully implemented at all hospitals (consent rates ranged from 59% to 74%) and 1670 participants were recruited. Data submission was variable: all hospitals submitted clinical data (for ≥82% of patients); only three hospitals submitted biochemistry data (for ≥98% of patients) and echocardiography data (for 34%–87% of patients); only one hospital submitted medications data (for 97% of patients). At the two CMR centres, 14% and 20% of patients received a CMR scan. Data submitted by hospitals were linked with HES and PEDW for 99% of all consented patients.

Conclusion

We successfully consented patients but obtaining individual, opt-in consent would not be feasible for a national registry. Linkage of data from HIS with hospital episode data was feasible. However, data from HIS are not uniformly available/exportable and, in centres with a dedicated CMR facility, some referrals for CMR were for research rather than clinical purposes.
Foundation Year 2 doctors’ reasons for leaving UK medicine: an in-depth analysis of decision-making using semistructured interviews
Authors: Smith Samantha E , Tallentire Victoria R , Pope Lindsey M , Laidlaw Anita H , Morrison Jill
Published: March 2018

Objectives

To explore the reasons that doctors choose to leave UK medicine after their foundation year two posts.

Setting

All four regions of Scotland.

Participants

Foundation year two doctors (F2s) working throughout Scotland who were considering leaving UK medicine after foundation training were recruited on a volunteer basis. Maximum variation between participants was sought.

Primary and secondary outcome measures

Semistructured interviews were coded using template analysis. Six perspectives, described by Feldman and Ng, were used as the initial coding template. The codes were then configured to form a framework that explores the interplay of factors influencing Foundation Year 2 (F2) doctors’ decisions to leave UK medicine.

Results

Seventeen participants were interviewed. Six perspectives were explored. Structural influences (countrywide and worldwide issues) included visas, economic and political considerations, structure of healthcare systems and availability of junior doctor jobs worldwide. Organisational influences (the National Health Service (NHS) and other healthcare providers) included staffing and compensation policies, the working environment and the learning environment. Occupational influences (specific to being a junior doctor) comprised the junior doctor contract, role and workload, pursuit of career interests and the structure of training. Work group influences (relationships with colleagues) included support at work, task interdependence and use of locums. Personal life influences consisted of work-life balance, and support in resolving work-life conflict. The underlying theme of ‘taking a break’ recurred through multiple narratives.

Conclusions

F2s give reasons similar to those given by any professional considering a change in their job. However, working within the NHS as an F2 doctor brought specific challenges, such as a need to make a choice of specialty within the F2 year, exposure to workplace bullying and difficulties in raising concerns. Despite these challenges, most F2s did not view their decision to leave as a permanent job change, but as a temporary break from their current working lives.
Comorbid psychiatric disorders in a clinical sample of adults with ADHD, and associations with education, work and social characteristics: a cross-sectional study
Authors: Anker Espen , Bendiksen Bothild , Heir Trond
Published: March 2018

Objectives

Adults with attention-deficit hyperactive disorder (ADHD) report high rates of comorbid disorders, educational and occupational failure, and family instability. The aim of this study was to examine the prevalence of comorbid psychiatric disorders in a clinical population of adults with ADHD and to examine associations between educational level, work participation, social characteristics and the rates of psychiatric comorbidity.

Methods

Out of 796 patients diagnosed with ADHD in a specialised outpatient clinic in Oslo, Norway, 548 (68%) agreed to participate in this cross-sectional study: 277 women and 271 men. ADHD was diagnosed according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria. Comorbid disorders were diagnosed using the Mini-International Neuropsychiatric Interview.

Results

In this clinical sample, 53.5% had at least one current comorbid psychiatric disorder. The most prevalent disorders were major depression, substance use disorders and social phobia. Women had more eating disorders than men, whereas men had more alcohol and substance use disorders. Education above high school level (>12 years) and work participation were associated with lower rates of comorbid disorders (adjusted ORs 0.52 and 0.63, respectively). Gender, age, marital status, living with children or living in a city were not associated with comorbidity.

Conclusions

Adult ADHD is associated with high rates of comorbid psychiatric disorders, irrespective of gender and age. It appears that higher education and work participation are related to lower probability of comorbidity.
‘Take Ten’ improving the surgical post-take ward round: a quality improvement project
Authors: Banfield Danielle Alice , Adamson Carly , Tomsett Amy , Povey James , Fordham Tony , Richards Sarah Kathryn
Published: March 2018

Background

The surgical post-take ward round is a complex multidisciplinary interaction in which new surgical patients are reviewed and management plans formulated. Its fast-paced nature can lead to poor communication and inaccurate or incomplete documentation with potential detriment to patient safety. Junior team members often do not fully understand the diagnosis and management plan.

Aims

The aims of this project were to improve both communication and documentation on the surgical post-take ward round, influencing patient safety.

Methods

The ward round was deconstructed to identify individual roles and determine where intervention would have the most impact. Ten important points were identified that should be documented in the management of an acute surgical patient; observations, examination, impression, investigations, antibiotics, intravenous fluids, VTE assessment, nutrition status, estimated length of stay and ceiling of treatment. A ‘Take Ten’ checklist was devised with these items to be used as a ‘time out’ after each patient with the whole team for discussion, clarification and clear documentation. Four plan do study act cycles were completed over a period of a year. A retrospective review of post-take documentation preintervention and postintervention was performed, and the percentage of points that were accurately documented was calculated. For further clarification, 2 weekends were compared—one where the checklist was used and one where it was not.

Results

Results showed documentation postintervention varied between categories but there was improvement in documentation of VTE assessment, fluids, observations and investigations. On direct comparison of weekends the checklist showed improved documentation in all categories except length of stay. Junior team members found the checklist improved understanding of diagnosis and management plan, and encouraged a more effective ward round.

Conclusion

The ‘Take Ten’ checklist has been well received. Three years on from its inception, the checklist has become an integral part of the post-take ward round, thanks to the multidisciplinary engagement in the project.
Symptom severity and its effect on health-related quality of life over time in patients with pulmonary hypertension: a multisite longitudinal cohort study
Authors: Yorke Janelle , Deaton Christi , Campbell Malcolm , McGowen Linda , Sephton Paul , Kiely David G , Armstrong Iain
Published: March 2018

Introduction

The aim of this cohort study was to examine health-related quality of life (HRQoL) and symptomatology in patients with pulmonary hypertension (PH) and explore factors that influence its evolution over time.

Methods

A prospective longitudinal multisite cohort study. Participants were recruited from specialist UK PH centres and completed a questionnaire pack at baseline, 6, 12 and 18 months to assess HRQoL (emPHasis-10), dyspnoea, fatigue, sleep, anxiety and depression.

Results

185 patients entered the study at baseline and 126 (68%) completed month 18. At baseline, patients had significant impairment of HRQoL, anxiety, depression, dyspnoea and severe fatigue. No significant changes, apart from a reduction in the Hospital Anxiety and Depression Scale-Anxiety score (P=0.04), were observed over 18 months. Depression and dyspnoea were predictors of HRQoL (P=0.002 and P=0.03, respectively). Oxygen use was also associated with diminished HRQoL and increased symptom severity.

Conclusion

Patients with PH experience high levels of symptom severity and the negative impact on HRQoL was unchanged over time. The use of oxygen therapy, in particular, was associated with a significant impact on HRQoL. Further study of factors impacting HRQoL and interventions that target a combination of physiological and psychosocial consequences of living with PH are needed.
What the new data protection regulation means for veterinary practices
Authors: Read Claire
Published: March 2018

On 25 May 2018, the General Data Protection Regulation (GDPR) will come into force, bringing with it new obligations for any organisation that handles personal data – including veterinary practices. Here, Claire Read examines the new law, and considers the preparations necessary to make practices compliant.
Towards a national genomics medicine service: the challenges facing clinical-research hybrid practices and the case of the 100 000 genomes project
Authors: Dheensa Sandi , Samuel Gabrielle , Lucassen Anneke M , Farsides Bobbie
Published: March 2018

Clinical practice and research are governed by distinct rules and regulations and have different approaches to, for example, consent and providing results. However, genomics is an example of where research and clinical practice have become codependent. The 100 000 genomes project (100kGP) is a hybrid venture where a person can obtain a clinical investigation only if he or she agrees to also participate in ongoing research—including research by industry and commercial companies. In this paper, which draws on 20 interviews with professional stakeholders involved in 100kGP, we investigate the ethical issues raised by this project’s hybrid nature. While some interviewees thought the hybrid nature of 100kGP was its vanguard, interviewees identified several tensions around hybrid practice: how to decide who should be able to participate; how to determine whether offering results might unduly influence participation into wide-ranging but often as yet unknown research and how to ensure that patients/families do not develop false expectations about receiving results. These areas require further debate as 100kGP moves into routine healthcare in the form of the national genomic medicine service. To address the tensions identified, we explore the appropriateness of Faden et al.’s framework of ethical obligations for when research and clinical care are completely integrated. We also argue that enabling ongoing transparent and trustworthy communication between patients/families and professionals around the kinds of research that should be permitted in 100kGP will help to understand and ensure that expectations remain realistic. Our paper aims to encourage a focused discussion about these issues and to inform a new ‘social contract’ for research and clinical care in the health service.
Effect of bio-cementation on geophysical and cone penetration measurements in sands
Authors: Gomez Michael G. , DeJong Jason T. , Anderson Collin M.
Published: March 2018

Microbially induced calcite precipitation (MICP) is a potentially environmentally conscious ground improvement method that can improve the engineering properties of granular soils through the precipitation of calcite. In this study, an experiment involving two 1.7 m diameter tank specimens was completed to investigate the effect of bio-cementation on cone penetrometer and geophysical measurements in sands. Following nonuniform bio-cementation treatments, specimens achieved calcite contents ranging from 0.5% to 5.3% by mass, shear wave velocity (Vs) values between 131 and 967 m/s, and mid-depth cone penetration resistances (qc) ranging between 3.6 and 32.1 MPa. At calcite contents exceeding 5.0%, qcand Vsimprovements were as high as 527% and 686%, respectively. Although cone penetration resistance, sleeve friction, and friction ratio measurements exhibited limited sensitivity to bio-cementation at calcite contents of less than 3.0%, Vsmeasurements successfully detected bio-cementation at calcite contents near 1.0%. When qcand Vsmeasurements were compared at similar locations, increases in an empirical parameter (KG) enabled improved detection of bio-cementation at calcite contents near 0.5%. Large increases in normalized tip resistances (Qtn) and small decreases in normalized friction ratios (Fr) with increasing bio-cementation resulted in cemented materials plotting near and within the gravelly sand and sand-like dilative soil behavioral type regions using two soil behavior type (SBT) charts.
Deformation–failure mechanism of saturated fill slopes due to resonance phenomena based on 1gshaking-table tests
Authors: Murao Hidehiko , Nakai Kentaro , Noda Toshihiro , Yoshikawa Takahiro
Published: March 2018

Earthquake motions include waves of various frequency bands ranging from low to high frequency. Notably, the dominant frequency affects the seismic stability of fill slopes. Hence, to analyze the deformation–failure mechanism during an earthquake, 1g shaking-table tests were conducted in this study on saturated fill slopes considering the resonance phenomenon. Results show that the deformation–failure mechanism of a fill slope cannot be defined by only one sliding surface. Multiple sliding surfaces are formed progressively depending on the ground and external conditions. Moreover, evaluating the seismic stability of fill slopes depends not only on the magnitude of the acceleration, but also on the relationship between the natural frequency of the fill slope and the input frequency. These phenomena cannot be considered in the seismic-intensity method nor in the Newmark’s method used in conventional design. When implementing seismic countermeasures, it is important to determine the frequency characteristics of fill slopes and design the countermeasures considering the predominant frequency of the seismic wave anticipated at the site.
Can trees at high elevations compensate for growth reductions at low elevations due to climate warming?
Authors: Vospernik Sonja , Nothdurft Arne
Published: March 2018

Radial tree stem growth of Norway spruce (Picea abies (L.) H. Karst.), European beech (Fagus sylvatica L.), Scots pine (Pinus sylvestris L.), and stone pine (Pinus cembra L.) was monitored from 2012 to 2015 across sites in Austria with high-resolution dendrometers. Seasonal cumulative diameter increment was modeled using a hierarchical nonlinear mixed-effects model framework based on a logistic growth curve. In the dry and warm year 2015, the average annual diameter increment of 0.30 cm decreased by 50% on lower elevation sites and by 10% on higher elevation sites. In the cool and moist year 2014, Norway spruce achieved a higher annual diameter increment than European beech, whereas the opposite occurred in the dry and warm years 2013 and 2015. In the mixed beech–spruce stand, beech’s consumptive water-use strategy has obviously caused intensified stress for spruce in these drought periods. On higher elevation sites, Norway spruce reacted more sensitively to climate fluctuation compared with stone pine, but overall reactions were only weak. Productivity varied strongly depending on the social status of the tree, with dominant and intermediate trees suffering more from drought. As warming and drought lowers increment rates on lower elevation sites and as trees on higher elevation sites react less flexibly, productivity losses are expected for Austrian forests due to climate warming.
The Higgs properties in the MSSM after the LHC Run-2
Authors: Zhao Jun
Published: March 2018

We scrutinize the parameter space of the SM-like Higgs boson in the minimal supersymmetric standard model (MSSM) under current experimental constraints. The constraints are from (i) the precision electroweak data and various flavor observables; (ii) the direct 22 separate ATLAS searches in Run-1; (iii) the latest LHC Run-2 Higgs data and tri-lepton search of electroweakinos. We perform a scan over the parameter space and find that the Run-2 data can further exclude a part of parameter space. For the property of the SM-like Higgs boson, its gauge couplings further approach to the SM values with a deviation below 0.1%, while its Yukawa couplings [Formula: see text] and [Formula: see text] can still sizably differ from the SM predictions by several tens percent.
Analysis of photonic band gap in novel piezoelectric photonic crystal
Authors: Malar Kodi A. , Doni Pon V. , Joseph Wilson K. S.
Published: March 2018

The transmission properties of one-dimensional novel photonic crystal having silver-doped novel piezoelectric superlattice and air as the two constituent layers have been investigated by means of transfer matrix method. By changing the appropriate thickness of the layers and filling factor of nanocomposite system, the variation in the photonic band gap can be studied. It is found that the photonic band gap increases with the filling factor of the metal nanocomposite and with the thickness of the layer. These structures possess unique characteristics enabling one to operate as optical waveguides, selective filters, optical switches, integrated piezoelectric microactuators, etc.
The collapsar model of gamma ray burst central engine
Authors: Tsuruta Sachiko , Leung Shing-Chi , Nomoto Ken’ichi
Published: March 2018

Gamma ray bursts (GRBs) are the most explosive and brightest known photon sources in the universe. The initial bursts of GRBs found so far typically have a spectral peak between [Formula: see text][Formula: see text]keV and 1[Formula: see text]MeV. Most of their gamma ray prompt emissions last for [Formula: see text][Formula: see text]s or less. The jets ejected from ‘the central engine’ are thought to be responsible for these bursts. According to the currently accepted scenario, a black hole produced by the merger of compact objects (such as black holes and/or neutron stars) is responsible for shorter bursts while collapse of a massive star directly to a black hole produces longer bursts, although clear-cut distinction may not exist. In this paper, we consider the latter case, a collapsar model responsible for longer GRBs. They are more interesting in the sense that they are more energetic and hence their studies can be extended to first Population III GRBs, which may give some constraints on the understanding of the early universe. In this paper, we are interested mainly in the “central engine”, the region created by the collapse of a rotating massive star to a spinning black hole and its surrounding area created by the stellar remnant because the conditions of the jet propagation change once they are outside in the interstellar medium. We first follow the process of how a progenitor massive star collapses and forms a central disk-black hole system, how powerful jets are produced and ejected from that system, and how the jets propagate and penetrate the surrounding stellar medium. The continued journey of the jets outside the star and the mechanisms for GRB emissions are outside the scope of this short paper.
A novel method for renormalization in quantum-field theory in curved spacetime
Authors: Freitas Gabriel , Casals Marc
Published: March 2018

In quantum-field theory in curved spacetime, two important physical quantities are the expectation value of the stress-energy tensor [Formula: see text] and of the square of the field operator [Formula: see text]. These expectation values must be renormalized, which is usually performed via the so-called point-splitting prescription. However, the renormalization method that is usually implemented in the literature, in principle, only applies to static, spherically-symmetric spacetimes, and does not readily generalize to other types of spacetime. We present a novel implementation of the renormalization procedure which may be used in the future for more general spacetimes, such as Kerr black hole spacetime. As an example, we apply our method to the renormalization of [Formula: see text] for a massless scalar field in Bertotti–Robinson spacetime.
The cosmological constant problem and quantum spacetime reference frame
Authors: Luo M. J.
Published: March 2018

We generalize the idea of quantum clock time to quantum spacetime reference frame via physical realization of a reference system by quantum rulers and clocks. Omitting the internal degrees of freedom (such as spins) of the physical rulers and clocks, only considering their metric properties, the spacetime reference frame is described by a bosonic nonlinear sigma model (NLSM). We study the quantum behavior of the system under approximations, and obtain (1) a cosmological constant valued [Formula: see text] ([Formula: see text] the critical density at near current epoch) which is very close to the observations; (2) an effective Einstein–Hilbert term; (3) the ratio of variance to mean-squared of spacetime interval tends to a universal constant [Formula: see text] in the infrared region. This effect is testable by observing a linear dependence between the inherent quantum variance and mean-squared of the redshifts from cosmic distant spectral lines. The proportionality is expected to be the observed percentage of the dark energy. The equivalence principle is also generalized to the quantum level.
Direct experimental detection of spatially localized clusters in nuclei on alpha-particle beams
Authors: Zaripova Y. A. , Dyachkov V. V. , Yushkov A. V. , Zholdybaev T. K. , Gridnev D. K.
Published: March 2018

Direct method for detecting intranuclear clusters of nuclear matter-clusters and determining their effective numbers was developed. The idea of the method is based on the functional coincidence of kinematics for light nuclei in the free state and clusters of the same mass within the nuclear volume. The reliability of the method is additionally confirmed by two experimental methods. The experiments were carried out at the Kazakhstan U-150M accelerator on a beam of [Formula: see text]-particles with energy of 29[Formula: see text]MeV. The first method consists in measuring the half-width of the elastic scattering peak from the angle and a comparison between the differential cross-sections of elastically scattered [Formula: see text] particles on free light nuclei and the differential cross-sections obtained by the authors on intranuclear multicluster. Using the second method, the correlation method, an experiment was performed to record the scattered [Formula: see text] particle on the 9Be nucleus-matrix and the recoil nucleus identical to it ([Formula: see text] particle). Thus, the kinematics of the [Formula: see text] 4He reaction, where 4He is an intranuclear [Formula: see text] cluster, indicates the presence of an intranuclear alpha cluster, which is further confirmed by the authors, an experimental measurement of intranuclear multicluster.
Nonlinear Stability Behavior of Cable-Stiffened Single-Layer Latticed Shells Under Earthquakes
Authors: Li Pengcheng , Wang Lei
Published: March 2018

A cable-stiffened single-layer latticed shell is an efficient and lightweight structural system in the category of spatial structures. In the past, much emphasis was placed on determining the static stability behavior of this structural system. Relatively little research was attempted on the seismic behavior of cable-stiffened single-layer latticed shells. The article aims to investigate numerically the seismic behavior of this structural system and to compare the behavior of the cable-stiffened single-layer latticed shell with that of the conventional unstiffened shell. The natural vibration characteristics, including the vibration modes and natural frequencies, were examined initially by modal analysis. Subsequently, a time-history analysis was conducted to analyze the nonlinear behavior of the cable-stiffened single-layer latticed shell under the El Centro earthquake. It was demonstrated that the seismic behavior of single-layer latticed shells can be greatly enhanced by the cable-stiffening system. In addition, the effects of pretension in cables, cross-sectional area, and other parameters relating to the seismic behavior of the cable-stiffened latticed shell have also been investigated.
A REVIEW OF FINITE ELEMENT APPLICATIONS IN ORAL AND MAXILLOFACIAL BIOMECHANICS
Authors: DOGRU SUZAN CANSEL , CANSIZ EROL , ARSLAN YUNUS ZIYA
Published: March 2018

Finite element method (FEM) is preferred to carry out mechanical analyses for many complex biomechanical structures. For most of the biomechanical models such as oral and maxillofacial structures or patient-specific dental instruments, including nonlinearities, complicated geometries, complex material properties, or loading/boundary conditions, it is not possible to accomplish an analytical solution. The FEM is the most widely used numerical approach for such cases and found a wide range of application fields for investigating the biomechanical characteristics of oral and maxillofacial structures that are exposed to external forces or torques. The numerical results such as stress or strain distributions obtained from finite element analysis (FEA) enable dental researchers to evaluate the bone tissues subjected to the implant or prosthesis fixation from the viewpoint of (i) mechanical strength, (ii) material properties, (iii) geometry and dimensions, (iv) structural properties, (v) loading or boundary conditions, and (vi) quantity of implants or prostheses. This review paper evaluates the process of the FEA of the oral and maxillofacial structures step by step as followings: (i) a general perspective on the techniques for creating oral and maxillofacial models, (ii) definitions of material properties assigned to oral and maxillofacial tissues and related dental materials, (iii) definitions of contact types between tissue and dental instruments, (iv) details on loading and boundary conditions, and (v) meshing process.
PROPOSAL OF CRITERIA FOR THE EVALUATION OF PRECISION AND FORCE IN HAND PROSTHESES
Authors: DÍAZ-MONTES JULIO C. , DORADOR-GONZÁLEZ JESÚS M.
Published: March 2018

There are indicators useful to measure the grasp quality of prostheses, two of them are the force that can be reached, and the precision needed to grasp an object. It is important to evaluate force and precision in hand prostheses because these characteristics are directly related to its performance and to the activities that can be done with it. Nowadays, there are no available criteria to evaluate these two characteristics. Existing criteria can be applied only in particular situations and can be applied only to a few prosthetic devices to obtain a general evaluation. This paper presents a proposal for criteria able to evaluate precision and force in-hand prosthetic devices. These criteria have three main original characteristics: Each system in the prosthesis is evaluated individually; quantitative information about its performance is obtained; the criteria can be used for evaluating most of the existing prosthetic devices. In order to show the application and use of the criteria the evaluation of two devices is presented: CDMIT© and SmartHand©. Prosthesis evaluation results show that both prosthesis have some particular aspects that can be improved, and thus reach a higher force and better precision. Criteria presented in this paper serve for stablishing a framework useful for compare several prosthesis in various aspects.
ELECTROMAGNETICALLY INDUCED DISTORTION OF A FIBRIN MATRIX WITH EMBEDDED MICROPARTICLES
Authors: SCOGIN TYLER , YESUDASAN SUMITH , WALKER MITCHELL L. R. , AVERETT RODNEY D.
Published: March 2018

Blood clots occur in the human body when they are required to prevent bleeding. In pathological states such as diabetes and sickle cell disease, blood clots can also form undesirably due to hypercoagulable plasma conditions. With the continued effort in developing fibrin therapies for potential life-saving solutions, more mechanical modeling is needed to understand the properties of fibrin structures with inclusions. In this study, a fibrin matrix embedded with magnetic micro particles (MMPs) was subjected to a magnetic field to determine the magnitude of the required force to create plastic deformation within the fibrin clot. Using finite element (FE) analysis, we estimated the magnetic force from an electromagnet at a sample space located approximately 3[Formula: see text]cm away from the coil center. This electromagnetic force coupled with gravity was applied on a fibrin mechanical system with MMPs to calculate the stresses and displacements. Using appropriate coil parameters, it was determined that application of a magnetic field of 730[Formula: see text]A/m on the fibrin surface was necessary to achieve an electromagnetic force of 36[Formula: see text]nN (to engender plastic deformation).
Active Tactile Exploration Based on Cost-Aware Information Gain Maximization
Authors: Ottenhaus Simon , Kaul Lukas , Vahrenkamp Nikolaus , Asfour Tamim
Published: March 2018

Active tactile perception is a powerful mechanism to collect contact information by touching an unknown object with a robot finger in order to enable further interaction with the object or grasping of the object. The acquired object knowledge can be used to build object shape models based on such usually sparse tactile contact information. In this paper, we address the problem of object shape reconstruction from sparse tactile data gained from a robot finger that yields contact information and surface orientation at the contact points. To this end, we present an exploration algorithm which determines the next best touch target in order to maximize the estimated information gain and to minimize the expected costs of exploration actions. We introduce the Information Gain Estimation Function (IGEF), which combines different goals as measure for the quantification of the cost-aware information gain during exploration. The IGEF-based exploration strategy is validated in simulation using 48 publicly available object models and compared to state-of-the-art Gaussian processes-based exploration approaches. The results show the performance of the approach regarding exploration efficiency, cost-awareness and suitability for application in real tactile sensing scenarios.
Stability Analysis of Smoothed Finite Element Methods with Explicit Method for Transient Heat Transfer Problems
Authors: Rong Xin , Niu Ruiping , Liu Guirong
Published: March 2018

In this paper, transient heat transfer problems are analyzed using the smoothed finite element methods (S-FEMs) with explicit time integration. For a numerical method with spatial discretization, the computational cost per time step in the explicit method is less than that in the implicit method, but the time step is much smaller in the explicit analysis than that in the implicit analysis when the same mesh is used. This is because the stability is of essential importance. This work thus studies the stability of S-FEMs, when applied to transient heat transfer problems. Relationships are established between the critical time steps used in S-FEMs with the maximum eigenvalues of the thermal stiffness (conduction) matrix and mass matrix. It is found that the critical time step relates to the “softness” of the model. For example, node-based smoothed finite element method (NS-FEM) is softer than edge-based smoothed finite element method (ES-FEM), which leads to that the critical time step of NS-FEM is larger than that of ES-FEM. Because computing the eigenvalues and condition numbers of the stiffness matrices is very expensive but valuable for stability analysis, we proposed a concise and effective algorithm to estimate the maximum eigenvalue and condition number. Intensive numerical examples show that our scheme for computing the critical time step can work accurately and stably for the explicit method in FEM and S-FEMs.
A New Fast Algorithm Based on Half-Step Discretization for 3D Quasilinear Hyperbolic Partial Differential Equations
Authors: Mohanty R. K. , Khurana Gunjan
Published: March 2018

In this paper, we study a new numerical method of order 4 in space and time based on half-step discretization for the solution of three-space dimensional quasi-linear hyperbolic equation of the form [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] subject to prescribed appropriate initial and Dirichlet boundary conditions. The scheme is compact and requires nine evaluations of the function [Formula: see text] For the derivation of the method, we use two inner half-step points each in [Formula: see text]-, [Formula: see text]-, [Formula: see text]- and [Formula: see text]-directions. The proposed method is directly applicable to three-dimensional (3D) hyperbolic equations with singular coefficients, which is main attraction of our work. We do not require extra grid points for computation. The proposed method when applied to 3D damped wave equation is shown to be unconditionally stable. Operator splitting method is used to solve 3D linear hyperbolic equations. Few benchmark problems are solved and numerical results are provided to support the theory which is discussed in this paper.
Exact solutions of Zabolotskaya–Khokhlov equation using optimal system
Authors: Umair Mohsin , Feroze Tooba
Published: March 2018

In this paper, using the Lie symmetry method, we obtain optimal system, group invariants and exact solutions of [Formula: see text] dimensional Zabolotskaya–Khokhlov equation.
A geometric approach to the transpositional relations in dynamics of nonholonomic mechanical systems
Authors: Khajeh Salehani Mahdi
Published: March 2018

Exploring the geometry of mechanical systems subject to nonholonomic constraints and using various bundle and variational structures intrinsically present in the nonholonomic setting, we study the structure of the equations of motion in a way that aids the analysis and helps to isolate the important geometric objects that govern the motion of such systems. Furthermore, we show that considering different sets of transpositional relations corresponding to different transitivity choices provides different variational structures associated with nonholonomic dynamics, but the derived equations (being referred to as the generalized Hamel–Voronets equations) are equivalent to the Lagrange–d’Alembert equations. To illustrate results of this work and as some applications of the generalized Hamel–Voronets formalisms discussed in this paper, we conclude with considering the balanced Tennessee racer, as well as its modification being referred to as the generalized nonholonomic cart, and an [Formula: see text]-snake with three wheeled planar platforms whose snake-like motion is induced by shape variations of the system.
Structural study of fluoro-tetraphenylporphyrins relating to large variability in solubilities of the para-F-TPP, ortho-F-TPP and meta-F-TPP
Authors: Han Ruxian , Kim Scott , Janda Kenneth J. , Fleischer Everly B.
Published: March 2018

We present the X-ray structures of the crystals of the ortho-, meta-, and para-F-tetraphenylporphyrins crystallized from different solvents to shed light on the differential solubility of these three isomers. The meta-F-TPP is 4300 times more soluble than the para-F-TPP isomer in chloroform. It is shown that the packing of the porphyrins in the crystal is not a key issue in this solubility difference. However, we discovered a large difference in the temperature factors of the phenyls and Fs in the various isomers and this gives us insight into the solubility differences.
Thermorheological characteristics and comparison of shape memory polymers fabricated by novel 3D printing technique
Authors: Hassan Rizwan Ul , Jo Soohwan , Seok Jongwon
Published: March 2018

The feasibility of fabrication of shape memory polymers (SMPs) was investigated using a customized 3-dimensional (3D) printing technique with an excellent resolution that could be less than 100 microns. The thermorheological effects of SMPs were adjusted by contact and non-contact triggering, which led to the respective excellent shape recoveries of 100% and 99.89%. Thermogravimetric analyses of SMPs resulted in a minor weight loss, thereby revealing good thermal stability at higher temperatures. The viscoelastic properties of SMPs were measured using dynamic mechanical analyses, exhibiting increased viscous and elastic characteristics. Mechanical strength, thermal stability and viscoelastic properties, of the two SMPs were compared [di(ethylene) glycol dimethacrylate (DEGDMA) and poly (ethylene glycol) dimethacrylate (PEGDMA)] to investigate the shape memory behavior. This novel 3D printing technique can be used as a promising method for fabricating smart materials with increased accuracy in a cost-effective manner.
Supercontinents and the case for Pannotia
Authors: Nance R. Damian , Murphy J. Brendan
Published: March 2018

Disagreement about the existence of the late Neoproterozoic supercontinent Pannotia highlights the limitation of defining supercontinents simply on the basis of size, which, for pre-Pangaean supercontinents, is difficult to determine. In the context of the supercontinent cycle, however, supercontinent assembly and break-up, respectively, mark the end of one cycle and the beginning of the next and can be recognized by the tectonic, climatic and biogeochemical trends that accompany them. Hence supercontinents need only be large enough to influence mantle circulation in such a way as to enable the cycle to repeat. Their recognition need not rely solely on continental reconstructions, but can also exploit a variety of secular trends that accompany their amalgamation and break-up. Although the palaeogeographical and age constraints for the existence of Pannotia remain equivocal, the proxy signals of supercontinent assembly and break-up in the late Neoproterozoic are unmistakable. These signals cannot be readily attributed to either the break-up of Rodinia or the assembly of Gondwana without ignoring either the assembly phase of Pan-African orogenesis and the changes in mantle circulation that accompany this phase, or the reality that Gondwana cannot be a supercontinent in the context of the supercontinent cycle because its break-up coincides with that of Pangaea.
Exploring the theory of plate tectonics: the role of mantle lithosphere structure
Authors: Heron Philip J. , Pysklywec Russell N. , Stephenson Randell
Published: March 2018

This review of the role of the mantle lithosphere in plate tectonic processes collates a wide range of recent studies from seismology and numerical modelling. A continually growing catalogue of deep geophysical imaging has illuminated the mantle lithosphere and generated new interpretations of how the lithosphere evolves. We review current ideas about the role of continental mantle lithosphere in plate tectonic processes. Evidence seems to be growing that scarring in the continental mantle lithosphere is ubiquitous, which implies a reassessment of the widely held view that it is the inheritance of crustal structure only (rather than the lithosphere as a whole) that is most important in the conventional theory of plate tectonics (e.g. the Wilson cycle). Recent studies have interpreted mantle lithosphere heterogeneities to be pre-existing structures and, as such, linked to the Wilson cycle and inheritance. We consider the current fundamental questions in the role of the mantle lithosphere in causing tectonic deformation, reviewing recent results and highlighting the potential of the deep lithosphere in infiltrating every aspect of plate tectonics processes.
Structural Basis for G Protein–Coupled Receptor Signaling
Authors: Erlandson Sarah C. , McMahon Conor , Kruse Andrew C.
Published: March 2018

G protein–coupled receptors (GPCRs), which mediate processes as diverse as olfaction and maintenance of metabolic homeostasis, have become the single most effective class of therapeutic drug targets. As a result, understanding the molecular basis for their activity is of paramount importance. Recent technological advances have made GPCR structural biology increasingly tractable, offering views of these receptors in unprecedented atomic detail. Structural and biophysical data have shown that GPCRs function as complex allosteric machines, communicating ligand-binding events through conformational change. Changes in receptor conformation lead to activation of effector proteins, such as G proteins and arrestins, which are themselves conformational switches. Here, we review how structural biology has illuminated the agonist-induced cascade of conformational changes that culminate in a cellular response to GPCR activation.
Structure and Dynamics of Membrane Proteins from Solid-State NMR
Authors: Mandala Venkata S. , Williams Jonathan K. , Hong Mei
Published: March 2018

Solid-state nuclear magnetic resonance (SSNMR) spectroscopy elucidates membrane protein structures and dynamics in atomic detail to yield mechanistic insights. By interrogating membrane proteins in phospholipid bilayers that closely resemble biological membranes, SSNMR spectroscopists have revealed ion conduction mechanisms, substrate transport dynamics, and oligomeric interfaces of seven-transmembrane helix proteins. Research has also identified conformational plasticity underlying virus-cell membrane fusions by complex protein machineries, and β-sheet folding and assembly by amyloidogenic proteins bound to lipid membranes. These studies collectively show that membrane proteins exhibit extensive structural plasticity to carry out their functions. Because of the inherent dependence of NMR frequencies on molecular orientations and the sensitivity of NMR frequencies to dynamical processes on timescales from nanoseconds to seconds, SSNMR spectroscopy is ideally suited to elucidate such structural plasticity, local and global conformational dynamics, protein-lipid and protein-ligand interactions, and protonation states of polar residues. New sensitivity-enhancement techniques, resolution enhancement by ultrahigh magnetic fields, and the advent of 3D and 4D correlation NMR techniques are increasingly aiding these mechanistically important structural studies.
Multilevel Small-Area Estimation of Colorectal Cancer Screening in the United States
Authors: Berkowitz Zahava , Zhang Xingyou , Richards Thomas B. , Nadel Marion , Peipins Lucy A. , Holt James
Published: March 2018

Background: The U.S. Preventive Services Task Force recommends routine screening for colorectal cancer for adults ages 50 to 75 years. We generated small-area estimates for being current with colorectal cancer screening to examine sociogeographic differences among states and counties. To our knowledge, nationwide county-level estimates for colorectal cancer screening are rarely presented.

Methods: We used county data from the 2014 Behavioral Risk Factor Surveillance System (BRFSS; n = 251,360 adults), linked it to the American Community Survey poverty data, and fitted multilevel logistic regression models. We post-stratified the data with the U.S. Census population data to run Monte Carlo simulations. We generated county-level screening prevalence estimates nationally and by race/ethnicity, mapped the estimates, and aggregated them into state and national estimates. We evaluated internal consistency of our modeled state-specific estimates with BRFSS direct state estimates using Spearman correlation coefficients.

Results: Correlation coefficients were ≥0.95, indicating high internal consistency. We observed substantial variations in current colorectal cancer screening estimates among the states and counties within states. State mean estimates ranged from 58.92% in Wyoming to 75.03% in Massachusetts. County mean estimates ranged from 40.11% in Alaska to 79.76% in Florida. Larger county variations were observed in various race/ethnicity groups.

Conclusions: State estimates mask county variations. However, both state and county estimates indicate that the country is far behind the “80% by 2018” target.

Impact: County-modeled estimates help identify variation in colorectal cancer screening prevalence in the United States and guide education and enhanced screening efforts in areas of need, including areas without BRFSS direct-estimates. Cancer Epidemiol Biomarkers Prev; 27(3); 245–53. ©2018 AACR.