bluuebunny/crossref_metadata_2025 huggingface dataset:
Research‐active clinical nurses: against all odds
Authors: Siedlecki Sandra L , Albert Nancy M
Published: August 2016

Aims and objectives

To develop a theoretical understanding of factors that impact decisions of clinical nurses to conduct a research study.

Background

Only a small percentage of all nurses are research‐active and even fewer clinical nurses are research‐active. Several researchers have explored barriers to research activity by clinical nurses, but few have examined why, in spite of all odds, some clinical nurses are research‐active.

Design

As the purpose of this study was to develop a theoretical understanding of the research‐active nurse, a grounded theory approach was used.

Methods

The sample interviewed for this study consisted of registered nurses (n = 26) who worked in a hospital or ambulatory setting, had daily direct patient contact and had participated as principal investigator on at least one completed clinical nursing research study that was not in fulfilment of an educational requirement. The interviews were digitally recorded and analysed by two researchers using the constant comparative method.

Results

The findings from this study suggest that the conduct of research by clinical nurses was the direct result of a clinical trigger, characteristics and beliefs of the nurse about research and their role in generating knowledge, and the presence of support conditions, such as a research mentor.

Conclusions

Clinical nurses can and do conduct research, in spite of constraints due to a lack of time, money and/or knowledge, if they have access to research mentors and are practising in a research‐supportive environment.

Relevance to clinical practice

Nurses at the bedside are in a unique position to identify problems most in need of solutions. Findings from this study provide a foundation upon which to develop and test various programmes that seek to increase the number of clinical nurses who are research‐active.
Subacute nodular skin lesions
Authors: Ghosh Sudip Kumar , Rudra Olympia , Agarwal Megha
Published: August 2016

See Answer
Molecular phylogeny of the Cladophoraceae (Cladophorales, Ulvophyceae), with the resurrection of Acrocladus Nägeli and Willeella Børgesen, and the description of Lurbica gen. nov. and Pseudorhizoclonium gen. nov.
Authors: Boedeker Christian , Leliaert Frederik , Zuccarello Giuseppe C.
Published: August 2016

The taxonomy of the Cladophoraceae, a large family of filamentous green algae, has been problematic for a long time due to morphological simplicity, parallel evolution, phenotypic plasticity, and unknown distribution ranges. Partial large subunit (LSU) rDNA sequences were generated for 362 isolates, and the analyses of a concatenated dataset consisting of unique LSU and small subunit (SSU) rDNA sequences of 95 specimens greatly clarified the phylogeny of the Cladophoraceae. The phylogenetic reconstructions showed that the three currently accepted genera Chaetomorpha, Cladophora, and Rhizoclonium are polyphyletic. The backbone of the phylogeny is robust and the relationships of the main lineages were inferred with high support, only the phylogenetic position of both Chaetomorpha melagonium and Cladophora rupestris could not be inferred unambiguously. There have been at least three independent switches between branched and unbranched morphologies within the Cladophoraceae. Freshwater environments have been colonized twice independently, namely by the freshwater Cladophora species as well as by several lineages of the Rhizoclonium riparium clade. In an effort to establish monophyletic genera, the genera Acrocladus and Willeella are resurrected and two new genera are described: Pseudorhizoclonium and Lurbica.
Epistemicism, Distribution, and the Argument from Vagueness
Authors: Magidor Ofra
Published: August 2016

This paper consists of two parts. The first concerns the logic of vagueness. The second concerns a prominent debate in metaphysics. One of the most widely accepted principles governing the ‘definitely’ operator is the principle of Distribution: if ‘p’ and ‘if p then q’ are both definite, then so is ‘q’. I argue however, that epistemicists about vagueness (at least those who take a broadly Williamsonian line) should reject this principle. The discussion also helps to shed light on the elusive question of what, on this framework, it takes for a sentence to be borderline or definite. In the second part of the paper, I apply this result to a prominent debate in metaphysics. One of the most influential arguments in favour of Universalism about composition is the Lewis‐Sider argument from vagueness. An interesting question, however, is whether epistemicists have any particular reasons to resist the argument. I show that there is no obvious reason why epistemicists should resist the argument but there is a non‐obvious one: the rejection of Distribution argued for in the first part of the paper provides epistemicists with a unique way of resisting the argument from vagueness.
A Purely Recombinatorial Puzzle
Authors: Fritz Peter
Published: August 2016

A new puzzle of modal recombination is presented which relies purely on resources of first‐order modal logic. It shows that naive recombinatorial reasoning, which has previously been shown to be inconsistent with various assumptions concerning propositions, sets and classes, leads to inconsistency by itself. The context sensitivity of modal expressions is suggested as the source of the puzzle, and it is argued that it gives us reason to reconsider the assumption that the notion of metaphysical necessity is in good standing.
A putative molybdate transporter LjMOT1 is required for molybdenum transport in Lotus japonicus
Authors: Gao Jun‐Shan , Wu Fei‐Fei , Shen Zhi‐Lin , Meng Yan , Cai Yong‐Ping , Lin Yi
Published: August 2016

Molybdenum (Mo) is an essential micronutrient that is required for plant growth and development, and it affects the formation of root nodules and nitrogen fixation in legumes. In this study, Lotus japonicus was grown on MS solid media containing 0 nmol l−1 (−Mo), 103 nmol l−1 (+Mo) and 1030 nmol l−1 (10 × Mo) of Mo. The phenotypes of plants growing on the three different media showed no obvious differences after 15 days, but the plants growing on –Mo for 45 days presented typical symptoms of Mo depletion, such as a short taproot, few lateral roots and yellowing leaves. A Mo transporter gene, LjMOT1, was isolated from L. japonicus. It encoded 468 amino acids, including two conserved motifs, and was predicted to locate to chromosome 3 of the L. japonicus genome. A homology comparison indicated that LjMOT1 had high similarities to other MOT1 proteins and was closely related to GmMOT1. Subcellular localization indicated that LjMOT1 is localized to the plasma membrane. qRT‐PCR analyses showed that increasing Mo concentrations regulated the relative expression level of LjMOT1. Moreover, the Mo concentration in shoots was positively correlated to the expression of LjMOT1, but there was no such evident correlation in the roots. In addition, changes in the nitrate reductase activity were coincident with changes in the Mo concentration. These results suggest that LjMOT1 may be involved in the transport of Mo and provide a theoretical basis for further understanding of the mechanism of Mo transport in higher plants.
Adaptation to high temperature mitigates the impact of water deficit during combined heat and drought stress in C3 sunflower and C4 maize varieties with contrasting drought tolerance
Authors: Killi Dilek , Bussotti Filippo , Raschi Antonio , Haworth Matthew
Published: August 2016

Heat and drought stress frequently occur together, however, their impact on plant growth and photosynthesis (PN) is unclear. The frequency, duration and severity of heat and drought stress events are predicted to increase in the future, having severe implications for agricultural productivity and food security. To assess the impact on plant gas exchange, physiology and morphology we grew drought tolerant and sensitive varieties of C3 sunflower (Helianthus annuus) and C4 maize (Zea mays) under conditions of elevated temperature for 4 weeks prior to the imposition of water deficit. The negative impact of temperature on PN was most apparent in sunflower. The drought tolerant sunflower retained ribulose‐1,5‐bisphosphate carboxylase/oxygenase (RubisCO) activity under heat stress to a greater extent than its drought sensitive counterpart. Maize exhibited no varietal difference in response to increased temperature. In contrast to previous studies, where a sudden rise in temperature induced an increase in stomatal conductance (Gs), we observed no change or a reduction in Gs with elevated temperature, which alongside lower leaf area mitigated the impact of drought at the higher temperature. The drought tolerant sunflower and maize varieties exhibited greater investment in root‐systems, allowing greater uptake of the available soil water. Elevated temperatures associated with heat‐waves will have profound negative impacts on crop growth in both sunflower and maize, but the deleterious effect on PN was less apparent in the drought tolerant sunflower and both maize varieties. As C4 plants generally exhibit water use efficiency (WUE) and resistance to heat stress, selection on the basis of tolerance to heat and drought stress would be more beneficial to the yields of C3 crops cultivated in drought prone semi‐arid regions.
Platelet function testing in cardiac surgery
Authors: Agarwal S.
Published: August 2016

Bleeding in cardiac surgery is known to cause increased morbidity and mortality. The rise in the use of anti‐platelet medication has led to an increase in the number of patients presenting for cardiac surgery with platelet dysfunction, who are at a heightened risk of bleeding. However, the extent of platelet inhibition is well known to differ among individuals. In the past few years, a number of point‐of‐care platelet function testing devices, which may be able to assess platelet reactivity, have entered the market. This review will examine the devices most commonly studied and the evidence surrounding their use in cardiac surgery and their effect on blood loss.
Protein stability changes of the novel p.Arg180Cys mutant A glycosyltransferase resulted in a weak A phenotype
Authors: Lee H.‐S. , Choi K.‐M. , Won E. J. , Thi Phan M.‐T. , Lee S. Y. , Shin D.‐J. , Chun S. , Park G. , Kim S.‐K. , Lee K.‐B. , Lee H.‐J. , Cho D.
Published: August 2016

A novel A subgroup allele (c.538C>T p.Arg180Cys) showing weak A phenotype was found in a 30‐year‐old Korean woman with ABO discrepancy. Using 3D structural analysis, protein stability prediction and flow cytometric analysis of ABO antigen expression on HeLa cells transfected with plasmids containing the p.Arg180Cys mutant, we found that the Arg180 residue in the loop region of the A glycosyltransferases (GTA) structure plays significant role in stabilizing its closed conformation, which is required for substrate binding and catalysis study.
Enhanced Hypocycloid Gear Mechanism for Internal Combustion Engine Applications
Authors: Aziz ELsayed S. , Chassapis Constantin
Published: August 2016

This study investigates the incorporation of an “enhanced” hypocycloid gear mechanism (HGM) in the design and development of internal combustion engine applications. The design incorporates a uniquely geared drive that provides the means for the piston–rod assembly to transverse on a straight-line, while delivering sinusoidal profiles for piston velocity and acceleration. A further feature of this mechanism is that the pinion shafts allow for a variable leverage point between the planetary carrier assembly and the output. This characteristic provided a nonlinear rate of piston movement because of the elliptical path of the pivot around the axis of the output shaft, which by slowing down the piston movement at the top dead center (TDC) allows the truly constant-volume combustion to take place and leads to higher efficiency and higher work produced. The simulation results of the study showed that the hypocycloid gear engine produced higher in-cylinder pressure at TDC compared to the conventional slider–crank engine of the same size.
Wavelets Galerkin Method for the Fractional Subdiffusion Equation
Authors: Heydari M. H.
Published: August 2016

The time fractional subdiffusion equation (FSDE) as a class of anomalous diffusive systems has obtained by replacing the time derivative in ordinary diffusion by a fractional derivative of order 0<α<1. Since analytically solving this problem is often impossible, proposing numerical methods for its solution has practical importance. In this paper, an efficient and accurate Galerkin method based on the Legendre wavelets (LWs) is proposed for solving this equation. The time fractional derivatives are described in the Riemann–Liouville sense. To do this, we first transform the original subdiffusion problem into an equivalent problem with fractional derivatives in the Caputo sense. The LWs and their fractional operational matrix (FOM) of integration together with the Galerkin method are used to transform the problem under consideration into the corresponding linear system of algebraic equations, which can be simply solved to achieve the solution of the problem. The proposed method is very convenient for solving such problems, since the initial and boundary conditions are taken into account, automatically. Furthermore, the efficiency of the proposed method is shown for some concrete examples. The results reveal that the proposed method is very accurate and efficient.
Nonlinear System Identification Technique for a Base-Excited Structure Based on Modal Space Formulation
Authors: Doranga Sushil , Wu Christine Q.
Published: August 2016

Most of the nonlinear system identification techniques described in the existing literature required force and response information at all excitation degrees-of-freedom (DOFs). For cases, where the excitation comes from base motion, those methods cannot be applied as it is not feasible to obtain the measurements of motion at all DOFs from an experiment. The objective of this research is to develop the methodology for the nonlinear system identification of continuous, multimode, and lightly damped systems, where the excitation comes from the moving base. For this purpose, the closed-form expression for the equivalent force also known as the pseudo force from the measured data for the base-excited structure is developed. A hybrid model space is developed to find out the nonlinear restoring force at the nonlinear DOFs. Once the nonlinear restoring force is obtained, the nonlinear parameters are extracted using “multilinear least square regression” in a modal space. A modal space is chosen to express the direct and cross-coupling nonlinearities. Using a cantilever beam as an example, the proposed methodology is demonstrated, where the experimental setup, testing procedure, data acquisition, and data processing are presented. The example shows that the method proposed here is systematic and constructive for nonlinear parameter identification for base-excited structure.
Finite-Element Evaluation of Burst Pressure Models for Corroded Pipelines
Authors: Chandra Mondal Bipul , Sutra Dhar Ashutosh
Published: August 2016

Codes/standards have been developed to calculate accurately the burst pressure for corroded pipelines. Five burst pressure models are evaluated in this paper using three-dimensional finite-element (FE) analysis. The finite-element models are validated using burst test results available in the literature. The design codes/standards are found to calculate variable burst pressures with respect to the finite-element calculations and the laboratory test results. The variability in the calculated burst pressures is attributed to the use of different flow stresses for the material and different burst pressure reduction factors for the corroded geometry. The Folias factor is considered as the major parameter contributing to the burst pressure reduction factor. Three different equations are currently used to calculate the Folias factor in the design codes that are expressed in terms of l2/(Dt). However, the finite-element evaluation presented here reveals that the Folias factor also depends on other parameters such as the defect depth.
Modulation and Radial Migration of Turbine Hub Cavity Modes by the Rim Seal Purge Flow
Authors: Schädler R. , Kalfas A. I. , Abhari R. S. , Schmid G. , Voelker S.
Published: August 2016

In the present paper, the results of an experimental and numerical investigation of the hub cavity modes and their migration into the main annulus flow are presented. A one-and-a-half stage, unshrouded and highly loaded axial turbine configuration with three-dimensionally shaped blades and cylindrical end walls has been tested in an axial turbine facility. Both the blade design and the rim seal purge flow path are representative to modern high-pressure gas turbines. The unsteady flow field at the hub cavity exit region has been measured with the fast-response aerodynamic probe (FRAP) for two different rim seal purge flow rates. Furthermore, fast-response wall-mounted pressure transducers have been installed inside the cavity. Unsteady full-annular computational fluid dynamics (CFD) simulations have been employed in order to complement the experimental work. The time-resolved pressure measurements inside the hub cavity reveal clear cavity modes, which show a strong dependency on the injected amount of rim seal purge flow. The numerical predictions provide information on the origin of these modes and relate them to pronounced ingestion spots around the circumference. The unsteady probe measurements at the rim seal interface show that the signature of the hub cavity induced modes migrates into the main annulus flow up to 30% blade span. Based on that, an aerodynamic loss mechanism has been found, showing that the benefit in loss reduction by decreasing the rim seal purge flow rate is weakened by the presence of turbine hub cavity modes.
A Comprehensive Overview of Inertial Sensor Calibration Techniques
Authors: Poddar Shashi , Kumar Vipan , Kumar Amod
Published: August 2016

Inertial measurement unit (IMU) comprising of the accelerometer and gyroscope is prone to various deterministic errors like bias, scale factor, and nonorthogonality, which need to be calibrated carefully. In this paper, a survey has been carried out over different calibration techniques that try to estimate these error parameters. These calibration schemes are discussed under two broad categories, that is, calibration with high-end equipment and without any equipment. Traditional calibration techniques use high-precision equipment to generate references for calibrating inertial sensors and are generally laboratory-based setup. Inertial sensor calibration without the use of any costly equipment is further studied under two subcategories: ones based on multiposition method and others with Kalman filtering framework. Later, a brief review of vision-based inertial sensor calibration schemes is also provided in this work followed by a discussion which indicates different shortcomings and future scopes in the area of inertial sensor calibration.
Many-Objective Optimal Design of Sliding Mode Controls
Authors: Sardahi Yousef , Sun Jian-Qiao
Published: August 2016

This paper presents a many-objective optimal (MOO) control design of an adaptive and robust sliding mode control (SMC). A second-order system is used as an example to demonstrate the design method. The robustness of the closed-loop system in terms of stability and disturbance rejection are explicitly considered in the optimal design, in addition to the typical time-domain performance specifications such as the rise time, tracking error, and control effort. The genetic algorithm is used to solve for the many-objective optimization problem (MOOP). The optimal solutions known as the Pareto set and the corresponding objective functions known as the Pareto front are presented. To assist the decision-maker to choose from the solution set, we present a post-processing algorithm that operates on the Pareto front. Numerical simulations show that the proposed many-objective optimal control design and the post-processing algorithm are promising.
On the Biaxial Mechanical Response of Porcine Tricuspid Valve Leaflets
Authors: Amini Khoiy Keyvan , Amini Rouzbeh
Published: August 2016

Located on the right side of the heart, the tricuspid valve (TV) prevents blood backflow from the right ventricle to the right atrium. Similar to other cardiac valves, quantification of TV biaxial mechanical properties is essential in developing accurate computational models. In the current study, for the first time, the biaxial stress–strain behavior of porcine TV was measured ex vivo under different loading protocols using biaxial tensile testing equipment. The results showed a highly nonlinear response including a compliant region followed by a rapid transition to a stiff region for all of the TV leaflets both in the circumferential and in the radial directions. Based on the data analysis, all three leaflets were found to be anisotropic, and they were stiffer in the circumferential direction in comparison to the radial direction. It was also concluded that the posterior leaflet was the most anisotropic leaflet.
Computational Model of the Arterial and Venous Needle During Hemodialysis
Authors: Fulker David , Simmons Anne , Barber Tracie
Published: August 2016

Arteriovenous fistulae (AVF) are the favored choice of vascular access but still have poor long-term success. Hemodynamic parameters play an important role in vascular health and have been linked to the development of intimal hyperplasia (IH), a pathological growth of the blood vessel initiated by injury. This study aimed to investigate the hemodynamics surrounding the arterial needle (AN) and venous needle (VN), using computational fluid dynamics. A range of blood flow rates, needle positions, and needle orientations were examined. Disturbed flows were found around AN tip in both antegrade and retrograde orientations, which result in regions of high residency time on the surface of the vein and may disrupt endothelial function. Conversely, a high speed jet exits the VN, which produced high wall shear stresses (WSSs) at the point of impingement which can damage the endothelium. The secondary flows produced by jet dissipation also resulted in regions of high residency time, which may influence endothelial structure, leading to IH. The use of shallow needle angles, a blood flow rate of approximately 300 ml/min, and placement of the needle tip away from the walls of the vein mitigates this risk.
Sustainable Manufacturing Through Creation and Governance of
Eco-Industrial Parks
Authors: Farel Romain , Charrière Benoît , Thevenet Charlotte , Yune Jeremy H.
Published: August 2016

With the emergence of the concept of industrial ecology (IE) and the first discovery of its practice in an existent park in Kalundborg, the interest from the scientific community as well as from the public and private stakeholders has increased significantly. For more than a decade, a handful of national programs and private initiatives have been initiated worldwide to implement industrial ecology into existent or newly built industrial parks. To date, more than hundreds of eco-industrial parks (EIPs) have been established. However, the relationship between the context and the origin of EIP initiatives with its methodology of development and management is still not clearly defined. Therefore, the aim of this article is to contribute to filling this knowledge gap. The return of experiences of 19 EIPs worldwide, based on bibliographical and empirical research through literature review and field interviews, allows the definition of a trend in the creation and the management of EIPs according to the context of implementation. This investigation exposes the exclusive relationships between trigger factors to develop an EIP either economic, environmental, or a mix according to the bottom-up, top-down, or mixed approach of creation, respectively. Moreover, it highlights the association dependence between the natures of the approach with the coordination structure and consequently the influence of the social context and the presence of a certain gap of cohabitation of the two extreme systems, i.e., public and private.
Use of Clustered Covariance and Selective Measurement Data in Ensemble Smoother for Three-Dimensional Reservoir Characterization
Authors: Lee Kyungbook , Jung Seungpil , Lee Taehun , Choe Jonggeun
Published: August 2016

History matching is essential for estimating reservoir performances and decision makings. Ensemble Kalman filter (EnKF) has been researched for inverse modeling due to lots of advantages such as uncertainty quantification, real-time updating, and easy coupling with any forward simulator. However, it requires lots of forward simulations due to recursive update. Although ensemble smoother (ES) is much faster than EnKF, it is more vulnerable to overshooting and filter divergence problems. In this research, ES is coupled with both clustered covariance and selective measurement data to manage the two typical problems mentioned. As preprocessing work of clustered covariance, reservoir models are grouped by the distance-based method, which consists of Minkowski distance, multidimensional scaling, and K-means clustering. Also, meaningless measurement data are excluded from assimilation such as shut-in bottomhole pressures, which are too similar on every well. For a benchmark model, PUNQ-S3, a standard ES with 100 ensembles, shows severe over- and undershooting problem with log-permeability values from 36.5 to −17.3. The concept of the selective use of observed data partially mitigates the problem, but it cannot match the true production. However, the proposed method, ES with clustered covariance and selective measurement data together, manages the overshooting problem and follows histogram of the permeability in the reference field. Uncertainty quantifications on future field productions give reliable prediction, containing the true performances. Therefore, this research extends the applicatory of ES to 3D reservoirs by improving reliability issues.
Low-cost, high-performance nonevaporable getter pumps using nonevaporable getter pills
Authors: Kodama Hiraku , Ohno Shinya , Tanaka Masatoshi , Tanaka Masato , Okudaira Koji K. , Mase Kazuhiko , Kikuchi Takashi
Published: August 2016

Nonevaporable getter (NEG) pumps are widely used for maintaining a clean ultrahigh vacuum (UHV) of ≤10−8 Pa because of their high pumping speeds for hydrogen (H2) and active gases in the UHV region. In addition, they are oil free, evaporation free, sputtering free, sublimation free, magnetic field free, vibration free, economical, compact, lightweight, and energy saving. In the present paper, the authors report a new NEG pump which is composed of commercial 60 NEG pills (ϕ10 × 3 mm; 70 wt. % Zr, 24.6 wt. % V, and 5.4 wt. % Fe), titanium parts, a DN 40 conflat flange, and a tantalum heater. The NEG pills are vertically and radially aligned around the heater to maximize the effective area for pumping. After activation at 400 °C for 30 min, the pumping speeds of the NEG pump were measured with the orifice method. Pumping speeds of 140–130, 200–140, 190–130, and 35–17 l/s were estimated for H2, CO, CO2, and N2 gasses, respectively, in a pumped-quantity range of 0.01–0.1 Pa l. Since the NEG pump is composed of a heating unit and a NEG module, the pumping speeds can be improved by increasing the number of NEG modules. These NEG pumps are favorable alternatives to sputtering ion pumps or titanium sublimation pumps.
Sci‐Thur PM – Colourful Interactions: Highlights 02: A deterministic solution to the first order linear Boltzmann transport equation including magnetic fields
Authors: St. Aubin Joel , Keyvanloo Amir , Vassiliev Oleg , Fallone B. Gino
Published: August 2016

Purpose:

To develop a novel formalism including magnetic force in the linear Boltzmann transport equation (LBTE) and to solve this equation deterministically by developing a new numerical framework.

Methods:

The continuity equation in six dimensions was used to derive the magnetic force term in the LBTE. The phase space variables were discretized using the multigroup method for energy variables, the discontinuous finite element method (DFEM) for the spatial variables, and using two approaches for the angular variables: the standard discrete ordinates method (DOM), and a novel angular DFEM. The calculated dose for both techniques was compared to Monte Carlo.

Results:

It was found that the standard source iteration approach was unstable using the DOM with magnetic fields. The Krylov solver restarted GMRES(m) overcame the instability except for cases characterized by very low media densities and large magnetic fields where convergence stagnated using smaller restart parameters. Our novel angular DFEM framework overcame these instabilities for all cases tested. Comparison with Monte Carlo showed greater than 99% of points passing a 2%/2mm gamma criterion for the DOM, and 99% of points passing for the angular DFEM.

Conclusion:

A novel formalism to include magnetic force within the LBTE was derived and a new numerical framework to solve the resultant equations was developed and tested using two different angular discretization techniques. Both techniques provided excellent accuracy, but the angular DFEM proved to be more stable. Dose calculations with this formalism were proven to be highly accurate, equivalent to advanced Monte Carlo algorithms.
Sci‐Thur PM – Colourful Interactions: Highlights 05: Opal–the Oncology Patient Application
Authors: Joseph Ackeem , Herrera David , Kildea John , Hijal Tarek , Hendren Laurie
Published: August 2016

We describe Opal (Oncology portal and application), the mobile phone app and patient portal that we have developed and are deploying for Radiation Oncology patients at our cancer centre. Opal is a novel tool to empower patients with their own personal medical data, including appointment schedules, consultation notes, test results, radiotherapy treatment planning information and wait time management. Furthermore, due to its integration with our electronic medical record and treatment planning database, Opal will allow us to collect patient reported outcomes from consenting patients and link them directly with dose volume histograms and other treatment data.
Sci‐Thur PM ‐ Colourful Interactions: Highlights 08: ARC TBI using Single‐Step Optimized VMAT Fields
Authors: Hudson Alana , Gordon Deborah , Moore Roseanne , Balogh Alex , Pierce Greg
Published: August 2016

Purpose:

This work outlines a new TBI delivery technique to replace a lateral POP full bolus technique. The new technique is done with VMAT arc delivery, without bolus, treating the patient prone and supine. The benefits of the arc technique include: increased patient experience and safety, better dose conformity, better organ at risk sparing, decreased therapist time and reduction of therapist injuries.

Methods:

In this work we build on a technique developed by Jahnke et al. We use standard arc fields with gantry speeds corrected for varying distance to the patient followed by a single step VMAT optimization on a patient CT to increase dose inhomogeneity and to reduce dose to the lungs (vs. blocks).

To compare the arc TBI technique to our full bolus technique, we produced plans on patient CTs for both techniques and evaluated several dosimetric parameters using an ANOVA test.

Results and Conclusions:

The arc technique is able reduce both the hot areas to the body (D2% reduced from 122.2% to 111.8% p<0.01) and the lungs (mean lung dose reduced from 107.5% to 99.1%, p<0.01), both statistically significant, while maintaining coverage (D98% = 97.8% vs. 94.6%, p=0.313, not statistically significant).

We developed a more patient and therapist‐friendly TBI treatment technique that utilizes single‐step optimized VMAT plans. It was found that this technique was dosimetrically equivalent to our previous lateral technique in terms of coverage and statistically superior in terms of reduced lung dose.
Sci‐Thur PM – Brachytherapy 01: Fast brachytherapy dose calculations: Characterization of egs_brachy features to enhance simulation efficiency
Authors: Chamberland Marc , Taylor Randle E.P. , Rogers David W.O. , Thomson Rowan M.
Published: August 2016

Purpose:

egs_brachy is a fast, new EGSnrc user‐code for brachytherapy applications. This study characterizes egs_brachy features that enhance simulation efficiency.

Methods:

Calculations are performed to characterize efficiency gains from various features. Simulations include radionuclide and miniature x‐ray tube sources in water phantoms and idealized prostate, breast, and eye plaque treatments. Features characterized include voxel indexing of sources to reduce boundary checks during radiation transport, scoring collision kerma via tracklength estimator, recycling photons emitted from sources, and using phase space data to initiate simulations. Bremsstrahlung cross section enhancement (BCSE), uniform bremsstrahlung splitting (UBS), and Russian Roulette (RR) are considered for electronic brachytherapy.

Results:

Efficiency is enhanced by a factor of up to 300 using tracklength versus interaction scoring of collision kerma and by up to 2.7 and 2.6 using phase space sources and particle recycling respectively compared to simulations in which particles are initiated within sources. On a single 2.5 GHz Intel Xeon E5‐2680 processor cor, simulations approximating prostate and breast permanent implant ((2 mm)3 voxels) and eye plaque ((1 mm)3) treatments take as little as 9 s (prostate, eye) and up to 31 s (breast) to achieve 2% statistical uncertainty on doses within the PTV. For electronic brachytherapy, BCSE, UBS, and RR enhance efficiency by a factor >2000 compared to a factor of >104 using a phase space source.

Conclusion:

egs_brachy features provide substantial efficiency gains, resulting in calculation times sufficiently fast for full Monte Carlo simulations for routine brachytherapy treatment planning.
Sci‐Thur PM – Brachytherapy 02: Positional accuracy in Pd‐103 permanent breast seed implant (PBSI) brachytherapy at the Tom Baker Cancer Centre (TBCC)
Authors: Frederick Amy , Watt Elizabeth , Peacock Michael , Husain Siraj , Meyer Tyler , Roumeliotis Michael
Published: August 2016

Purpose:

This retrospective study aims to quantify the positional accuracy of seed delivery in permanent breast seed implant (PBSI) brachytherapy at the Tom Baker Cancer Centre (TBCC).

Methods:

Treatment planning and post‐implant CT scans for 5 patients were rigidly registered using the MIM Symphony™ software (MIM Software, Cleveland, OH) and used to evaluate differences between planned and implanted seed positions. Total and directional seed displacements were calculated for each patient in a clinically relevant ‘needle coordinate system’, defined relative to the angle of fiducial needle insertion.

Results:

The overall average total seed displacement was 10±8 mm. Systematic seed displacements were observed in individual patients and the magnitude and direction of these offsets varied among patients. One patient showed a significant directional seed displacement in the shallow‐deep direction compared with the other four patients. With the exception of this one patient outlier, no significant systematic directional displacements in the needle coordinate system were observed for this cohort; the average directional displacements were −1±5 mm, 2±3 mm, and −2±4 mm in the shallow‐deep, up‐down, and right‐left directions respectively.

Conclusion:

With the exception of one patient outlier, the magnitude of seed displacements were relatively consistent among patients. The results indicate that the shallow‐deep direction possesses the largest uncertainty for the seed delivery method used at the TBCC. The relatively large uncertainty in seed placement in this direction is expected, as this is the direction of needle insertion. Further work will involve evaluating deflections of delivered needle tracks from their planned positions.
Poster ‐ 09: A MATLAB‐based Program for Automated Quality Assurance of a Prostate Brachytherapy Ultrasound System
Authors: Poon Justin , Sabondjian Eric , Sankreacha Raxa
Published: August 2016

Purpose:

A robust Quality Assurance (QA) program is essential for prostate brachytherapy ultrasound systems due to the importance of imaging accuracy during treatment and planning. Task Group 128 of the American Association of Physicists in Medicine has recommended a set of QA tests covering grayscale visibility, depth of penetration, axial and lateral resolution, distance measurement, area measurement, volume measurement, and template/electronic grid alignment. Making manual measurements on the ultrasound system can be slow and inaccurate, so a MATLAB program was developed for automation of the described tests.

Methods:

Test images were acquired using a BK Medical Flex Focus 400 ultrasound scanner and 8848 transducer with the CIRS Brachytherapy QA Phantom – Model 045A. For each test, the program automatically segments the inputted image(s), makes the appropriate measurements, and indicates if the test passed or failed. The program was tested by analyzing two sets of images, where the measurements from the first set were used as baseline values.

Results:

The program successfully analyzed the images for each test and determined if any action limits were exceeded. All tests passed – the measurements made by the program were consistent and met the requirements outlined by Task Group 128.

Conclusions:

The MATLAB program we have developed can be used for automated QA of an ultrasound system for prostate brachytherapy. The GUI provides a user‐friendly way to analyze images without the need for any manual measurement, potentially removing intra‐ and inter‐user variability for more consistent results.
Poster ‐ 19: Investigation of Electron Reference Dosimetry Based on Optimal Chamber Shift
Authors: Zhan Lixin , Jiang Runqing , Liu Baochang , Osei Ernest
Published: August 2016

An addendum/revision to AAPM TG‐51 electron reference dosimetry is highly expected to meet the clinical requirement with the increasing usage of new ion chambers not covered in TG‐51. A recent study, Med. Phys. 41, 111701, proposed a new fitting equation for the beam quality conversion factor k’Q to a wide spectrum of chambers. In the study, an optimal Effective Point of Measurement (EPOM) from Monte Carlo calculations was recommended and the fitting parameters to k’Q was based on it. We investigated the absolute dose obtained based on the optimal EPOM method and the original TG‐51 method with k’R50 determined differently. The results showed that using the Markus curve is a better choice than the well‐guarded chamber fitting for an IBA PPC‐05 parallel plate chamber if we need to strictly follow the AAPM TG‐51 protocol. We also examined the usage of the new fitting equation with measurement performed at the physical EPOM, instead of the optimal EPOM. The former is more readily determined and more practical in clinics. Our study indicated that the k’Q fitting based on the optimal EPOM can be used to measurement at the physical EPOM with no significant clinical impact. The inclusion of Farmer chamber gradient correction Pgr in k’Q, as in the mentioned study, asks for the precise positioning of chamber center at dref. It is not recommended in clinics to avoid over‐correction for low electron energies, especially for an institute having matching Linacs implemented.
Poster ‐ 27: Incident Learning Practices in Ontario
Authors: Angers Crystal , Medlam Gaylene , Liszewski Brian , Simniceanu Carina
Published: August 2016

Purpose:

The Radiation Incident and Safety Committee (RISC), established and supported by Cancer Care Ontario (CCO), is responsible for advising the Provincial Head of the Radiation Treatment program on matters relating to provincial reporting of radiation incidents with the goal of improved risk mitigation.

Methods:

The committee is made up of Radiation Incident Leads (RILs) with representation from each of the 14 radiation medicine programs in the province. RISC routinely meets to review recent critical incidents and to discuss provincial reporting processes and future directions of the committee. Regular face to face meetings have provided an excellent venue for sharing incident learning practices. A summary of the incident learning practices across Ontario has been compiled.

Results:

Almost all programs in Ontario employ an incident learning committee to review incidents and identify corrective actions or process improvements. Tools used for incident reporting include: paper based reporting, a number of different commercial products and software solutions developed in‐house. A wide range of classification schema (data taxonomies) are employed, although most have been influenced by national guidance documents. The majority of clinics perform root cause analyses but utilized methodologies vary significantly.

Conclusions:

Most programs in Ontario employ a committee approach to incident learning. However, the reporting tools and taxonomies in use vary greatly which represents a significant challenge to provincial reporting. RISC is preparing to adopt the National System for Incident Reporting – Radiation Therapy (NSIR‐RT) which will standardize incident reporting and facilitate data analyses aimed at identifying targeted improvement initiatives.
Poster ‐ 29: A Review of Patient Specific QA to Enable Program Comparisons Across Centers
Authors: Lamey Michael , Rangel Alejandra , Robertson Merle
Published: August 2016

Purpose:

To aid comparison of the performance of patient specific QA (PSQA) programs across centers

Methods:

Up to 414 VMAT/IMRT plans from various treatment sites (most commonly prostate, prostate bed, lung and lung SBRT) from a year period of ArcCHECK measurements were analysed using a range of acceptance criteria including variations of the following parameters: Gamma or DTA, Relative (RD) or Absolute Dose (AD), Van Dyk and Threshold (TH). A total of 24 different criteria were selected in the SNC Patient software to evaluate each plan and determine all reportable passing rates (PR).

Results:

The average passing rate (Rateavg) for all plans using all combinations of criteria ranges from about 93% using “3% Dose, 2mm DTA, AD, 10% TH, no Van dyk” criteria to nearly 100% using “Gamma with 3%Dose, 3mm DTA, RD, 10% TH, no Van dyk”. The 90th percentile of passing rates was also quantified and ranges from about 85% to nearly 100%. When analysed by site, prostate and prostate bed plans show the highest Rateavg, while SBRT lung plans shows the widest spread of rates. As expected, Rateavg decreases as the selection of Gamma changes to DTA, AD changes to RD, and “Van dyk” is turned off. Additionally, Rateavg decreases as TH percent selection decreases.

Conclusions:

The results enable comparisons of PR considering criteria stringency hence enabling better comparison of PSQA programs across centres. The study allows better understanding on how the parameters affect the reported PR and the level of stringency from all combinations.
Poster ‐ 30: Use of a Hazard‐Risk Analysis for development of a new eye immobilization tool for treatment of choroidal melanoma
Authors: van Prooijen Monique , Breen Stephen
Published: August 2016

Purpose:

Our treatment for choroidal melanoma utilizes the GTC frame. The patient looks at a small LED to stabilize target position. The LED is attached to a metal arm attached to the GTC frame. A camera on the arm allows therapists to monitor patient compliance. To move to mask‐based immobilization we need a new LED/camera attachment mechanism. We used a Hazard‐Risk Analysis (HRA) to guide the design of the new tool.

Method:

A pre‐clinical model was built with input from therapy and machine shop personnel. It consisted of an aluminum frame placed in aluminum guide posts attached to the couch top. Further development was guided by the Department of Defense Standard Practice ‐ System Safety hazard risk analysis technique.

Results:

An Orfit mask was selected because it allowed access to indexes on the couch top which assist with setup reproducibility. The first HRA table was created considering mechanical failure modes of the device. Discussions with operators and manufacturers identified other failure modes and solutions. HRA directed the design towards a safe clinical device.

Conclusion:

A new immobilization tool has been designed using hazard‐risk analysis which resulted in an easier‐to‐use and safer tool compared to the initial design. The remaining risks are all low probability events and not dissimilar from those currently faced with the GTC setup. Given the gains in ease of use for therapists and patients as well as the lower costs for the hospital, we will implement this new tool.
Poster ‐ 46: Intra‐fraction tumor position assessment for lung SBRT in patients treated without customized immobilization devices
Authors: Alamri Iqbal , Faria Sergio , Gluszko Jessica , Patrocinio Horacio
Published: August 2016

Purpose:

To assess intra‐fraction positional stability of lung cancer tumours in patients treated by kilo‐voltage cone‐beam computed tomography (CBCT)‐guided stereotactic body radiotherapy (SBRT) without the use of customized immobilization devices.

Material and Methods:

Twenty‐two patients underwent 4D‐CT in the supine position with the arms in a wing board but without customized immobilization. The PTV was the internal target volume based on maximum intensity projections and a 5mm symmetric setup margin. Treatments were planned using 7–9 static fields or two volumetric modulated arcs. At treatment, the patient position was adjusted using pre‐treatment CBCT. A post‐treatment CBCT was taken immediately after the treatment ended. The 41 CBCT pairs were automatically matched and the transitional shifts between the two CBCTs recorded. The mean values and standard deviations were calculated for these displacements.

Results and conclusions:

The mean time between CBCTs (treatment time) was 16.5 ± 6 minutes (range: 10 to 34 minutes). In all cases the tumour remained inside the PTV in the post‐treatment CBCT. The mean shifts between pre and post‐treatment CBCTs were −0.7 ± 1.6 mm (range −5.0 to 3.0 mm) vertically, −0.3 ± 1.7 mm (range −4.8 to 3.0 mm) longitudinally, and −0.4 ± 1.5 mm (range −4.0 to 2.0 mm) laterally. Our results suggest little systematic shifting during treatment, and standard deviations that are consistent with another published report for treatments where customized immobilization was used. This result is encouraging for SBRT programs in clinics with limited resources.
Poster ‐ 47: A parametrized prediction model of rectal toxicity in focal SBRT of low risk prostate cancer
Authors: Stevens Todd , Bauman Glenn
Published: August 2016

There has been a recent trend towards watchful waiting in place of intervention for early stage prostate cancer (CaP). However, this approach can allow for disease progression, and subsequent whole‐gland therapies such as prostatectomy and whole gland irradiation can result in functional deficits or rectal toxicities or both. A controversial alternative approach for this patient cohort is the use of focal therapy, where the treatment is focussed on an identified dominant index lesion (DIL). This work aims to investigate the treatment parameters for focal SBRT of the prostate under which clinically acceptable rectal NTCP levels can be achieved.

For each of 25 low risk CaP patients, a hypothetical 2 cc DIL was modeled in the right‐posterior quadrant of the prostate, and was used to build a PTV as the target for SBRT simulation. An SBRT prescriptions of 41 Gy and 37 Gy in 5 fractions were chosen, corresponding to the boost levels used in previous CaP dose escalation studies. DVH data were exported and used to calculate rectal NTCP values based on the Lyman‐Kutcher‐Burman (LKB) model using the QUANTEC reccommended model parameters. Rectal NTCP dependence on DIL‐to‐rectum separation, dose level, and DIL volume were investigated. The final goal of this ongoing work is to create a map of the maximum allowable prescription dose for a given patient geometry that achieves a clinically acceptable rectal NTCP level.