bluuebunny/crossref_metadata_2025_split huggingface dataset:
Incidence, risk factors, and the impact of allograft pyelonephritis on renal allograft function
Authors: Singh R. , Geerlings S.E. , Peters‐Sengers H. , Idu M.M. , Hodiamont C.J. , ten Berge I.J.M. , Bemelman F.J. 
Published: July 2016

AbstractBackgroundThe impact of allograft pyelonephritis (AGPN) on renal allograft function is controversial. In this study, we evaluated the incidence, risk factors, and the impact of AGPN on renal allograft function.MethodsRetrospective cohort study in adult renal allograft recipients with 1‐year follow‐up after transplantation (Tx). Renal allograft function was evaluated by estimated glomerular filtration rate (eGFR) (by Modification of Diet in Renal Disease formula) and 24‐h urine protein excretion.ResultsA total of 431 renal allograft recipients were analyzed; 57 (13.2%) developed AGPN within 1 year after Tx. Median time between Tx and AGPN was 50 days. Risk factors for AGPN were the presence of a urological catheter (odds ratio [OR] = 18.93, 95% confidence interval [CI] = 8.00–44.81, P < 0.001) and preceding asymptomatic bacteriuria (ASB) (OR = 2.16, 95% CI = 1.20–3.90, P = 0.009). In 72.7%, the causative microorganism of ASB was identical to that of the succeeding AGPN episode. Multivariable linear regression analysis showed that experiencing AGPN did not decrease the eGFR (P = 0.61) nor did increased proteinuria (P = 0.29) 1 year after Tx. For the eGFR, an interaction was found between AGPN/bacteriuria (BU) and acute rejection (AR): the group experiencing BU preceding AR had significantly (P < 0.001) lower eGFR compared with the group that experienced only AR (21 mL/min/1.73 m2 vs. 48 mL/min/1.73 m2), as a result of increased prevalence of combined rejections within the BU group.ConclusionIndwelling urological catheters and preceding ASB are associated with developing AGPN. An incident of AGPN itself does not impair renal allograft function 1 year after Tx. However, a relevant interaction occurs between BU and AR, in which the sequence of occurrence of these 2 events synergistically impairs the eGFR.
Dimer/monomer status and in vivo function of salt‐bridge mutants of the plant UV‐B photoreceptor UVR8
Authors: Heilmann Monika , Velanis Christos N. , Cloix Catherine , Smith Brian O. , Christie John M. , Jenkins Gareth I. 
Published: July 2016

SummaryUV RESISTANCE LOCUS8 (UVR8) is a photoreceptor for ultraviolet‐B (UV‐B) light that initiates photomorphogenic responses in plants. UV‐B photoreception causes rapid dissociation of dimeric UVR8 into monomers that interact with CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1) to initiate signal transduction. Experiments with purified UVR8 show that the dimer is maintained by salt‐bridge interactions between specific charged amino acids across the dimer interface. However, little is known about the importance of these charged amino acids in determining dimer/monomer status and UVR8 function in plants. Here we evaluate the use of different methods to examine dimer/monomer status of UVR8 and show that mutations of several salt‐bridge amino acids affect dimer/monomer status, interaction with COP1 and photoreceptor function of UVR8 in vivo. In particular, the salt‐bridges formed between arginine 286 and aspartates 96 and 107 are key to dimer formation. Mutation of arginine 286 to alanine impairs dimer formation, interaction with COP1 and function in vivo, whereas mutation to lysine gives a weakened dimer that is functional in vivo, indicating the importance of the positive charge of the arginine/lysine residue for dimer formation. Notably, a UVR8 mutant in which aspartates 96 and 107 are conservatively mutated to asparagine is strongly impaired in dimer formation but mediates UV‐B responses in vivo with a similar dose–response relationship to wild‐type. The UV‐B responsiveness of this mutant does not correlate with dimer formation and monomerisation, indicating that monomeric UVR8 has the potential for UV‐B photoreception, initiating signal transduction and responses in plants.
take up #9as a semantic isogloss on the Canada‐US border
Authors: DOLLINGER STEFAN 
Published: July 2016

ABSTRACTThis paper explores semantic isoglosses of polysemous words, an understudied aspect of the Canada‐US border by drawing ontake up #9, an isogloss that appears to be spreading through the mainland Canadian population. The variable, which is approached from a philological‐lexicographic as well as a quantitative‐statistical perspective, is interpreted in the light of recent European cross‐borders studies. Analogues with the situations in Austrian German (Austria‐Germany) and British English (Scotland‐England) are drawn. Set in a pluricentric framework, this paper argues that the Canada‐US border remains a productive linguistic divide. Moreover, it is suggested that types of unexplored lexico‐semantic variables may be responsible for some identity work across this international border, one of only two contiguous borders among the Englishes of the Inner Circle.
Secondary hyperalgesia is mediated by heat‐insensitive A‐fibre nociceptors
Authors: van den Broeke Emanuel N. , Lenoir Cédric , Mouraux André 
Published: July 2016

Key points
It is believed that secondary hyperalgesia (the increased sensitivity to mechanical nociceptive stimuli that develops after cutaneous tissue injury in the surrounding uninjured skin) is mediated by a subclass of nociceptors: the slowly adapting A‐fibre mechano‐heat nociceptors (AMH‐type I). Here we tested this hypothesis.
By using intense long‐lasting heat stimuli, which are known to activate these slowly adapting AMH‐type I nociceptors, we show that the perceived intensity elicited by these stimuli is not increased in the area of secondary hyperalgesia.
Moreover, we show that during an A‐fibre nerve conduction block the perception elicited by the long‐lasting heat stimuli is significantly reduced in a time window that matches the response profile of the AMH‐type I nociceptors.
AMH‐type I nociceptors contribute to the perception of sustained heat, but they do not mediate secondary hyperalgesia. Therefore, we propose that secondary hyperalgesia is mediated by high threshold mechanoreceptors.
AbstractSecondary hyperalgesia refers to the increase in sensitivity to mechanical nociceptive stimuli delivered outside the area of tissue injury. Previous studies have suggested that secondary hyperalgesia is mediated by a specific class of myelinated nociceptors: slowly adapting A‐fibre mechano‐ and heat‐sensitive (AMH) type I nociceptors. Here, we tested this hypothesis by examining whether long‐lasting heat stimuli, which are known to activate AMH‐type I nociceptors, elicit enhanced responses when delivered to the area of secondary hyperalgesia induced by high frequency electrical stimulation of the skin (HFS). Before and 20 min after HFS, sustained 30 s radiant heat stimuli were delivered to the area of increased mechanical pinprick sensitivity while participants continuously rated intensity of perception using an online visual analog scale (0–100 mm). After HFS, no significant enhancement of heat perception was observed in the area of increased pinprick sensitivity. To establish that myelinated nociceptors actually contribute to the perception of sustained heat, we conducted a second experiment in which sustained heat stimuli were presented before and during an A‐fibre nerve conduction block, achieved by applying a rubber band with weights which compresses the superficial radial nerve against the radius. During the block, heat perception was significantly reduced 17–33 s after the onset of the heat stimulus (before: mean = 53 mm, during: mean = 31 mm; P = 0.03), matching the response profile of AMH‐type I nociceptors. These results support the notion that AMH‐type I nociceptors contribute to the perception of sustained heat, but also show that these afferents do not mediate secondary hyperalgesia.
SU‐A‐BRC‐03: The Path of a Small Business Owner
Authors: Childress N. 
Published: July 2016

This year's Annual Student Meeting consists of a panel of professionals who have pursued a traditional education in medical physics and have since pursued a variety of careers. These range from chief medical physicist, small business founder, FDA scientist, industry R&D scientist, and academic researcher. Each panelist will discuss their education, positions that they have held leading to their current one, and factors that influenced them to pursue their careers. Time will be left at the end of the talk to open the floor for questions from students and trainees. Discussion between the presenters and participants is encouraged.

Learning Objectives:
The audience will learn about how to prepare for a career in medical physics.
The audience will be able to consider some of the widely different job opportunities open to medical physicists.
The audience will gain a better understanding of some future challenges facing medical physics graduates.N. Childress, I am the owner of Mobius Medical Systems, LP.
SU‐B‐BRA‐01: Introduction
Authors: Sherouse G. 
Published: July 2016

In the current rapidly changing Healthcare environment, many groups are competing for limited resources. How can medical physicists position themselves to be a relevant stakeholder in the discussion of how those resources are allocated Our value goes beyond what can be shown in a business plan and is heavily involved with safety and quality.Three areas will be explored:
What is our value?
Who needs to receive that message?
How do we communicate that message?To help frame the discussion in terms of how other stakeholders may view the value of medical physicists, a physician and an administrator will present their perspective.Lastly, a multidisciplinary panel will present real life examples of strategies that can be utilized today to establish the value of medical physicists. The presentation of these examples will lead into an interactive question and answer time.V. Willcut, I work for Elekta. There was no research associated with this talk.
SU‐C‐201‐04: Noise and Temporal Resolution in a Near Real‐Time 3D Dosimeter
Authors: Rilling M , Goulet M , Beaulieu L , Thibault S , Archambault L 
Published: July 2016

Purpose:To characterize the performance of a real‐time three‐dimensional scintillation dosimeter in terms of signal‐to‐noise ratio (SNR) and temporal resolution of 3D dose measurements. This study quantifies its efficiency in measuring low dose levels characteristic of EBRT dynamic treatments, and in reproducing field profiles for varying multileaf collimator (MLC) speeds.Methods:The dosimeter prototype uses a plenoptic camera to acquire continuous images of the light field emitted by a 10×10×10 cm3 plastic scintillator. Using EPID acquisitions, ray tracing‐based iterative tomographic algorithms allow millimeter‐sized reconstruction of relative 3D dose distributions. Measurements were taken at 6MV, 400 MU/min with the scintillator centered at the isocenter, first receiving doses from 1.4 to 30.6 cGy. Dynamic measurements were then performed by closing half of the MLCs at speeds of 0.67 to 2.5 cm/s, at 0° and 90° collimator angles. A reference static half‐field was obtained for measured profile comparison.Results:The SNR steadily increases as a function of dose and reaches a clinically adequate plateau of 80 at 10 cGy. Below this, the decrease in light collected and increase in pixel noise diminishes the SNR; nonetheless, the EPID acquisitions and the voxel correlation employed in the reconstruction algorithms result in suitable SNR values (>75) even at low doses. For dynamic measurements at varying MLC speeds, central relative dose profiles are characterized by gradients at %D50 of 8.48 to 22.7 %/mm. These values converge towards the 32.8 %/mm‐gradient measured for the static reference field profile, but are limited by the dosimeter's current acquisition rate of 1Hz.Conclusion:This study emphasizes the efficiency of the 3D dose distribution reconstructions, while identifying limits of the current prototype's temporal resolution in terms of dynamic EBRT parameters. This work paves the way for providing an optimized, second‐generational real‐time 3D scintillation dosimeter capable of highly efficient and precise dose measurements.The presenting author is financially supported by an Alexander‐Graham Bell doctoral scholarship from the Natural Sciences and Engineering Research Council of Canada (NSERC).
SU‐C‐BRA‐07: Variability of Patient‐Specific Motion Models Derived Using Different Deformable Image Registration Algorithms for Lung Cancer Stereotactic Body Radiotherapy (SBRT) Patients
Authors: Dhou S , Ionascu D , Lewis J , Williams C 
Published: July 2016

Purpose:To study the variability of patient‐specific motion models derived from 4‐dimensional CT (4DCT) images using different deformable image registration (DIR) algorithms for lung cancer stereotactic body radiotherapy (SBRT) patients.Methods:Motion models are derived by 1) applying DIR between each 4DCT image and a reference image, resulting in a set of displacement vector fields (DVFs), and 2) performing principal component analysis (PCA) on the DVFs, resulting in a motion model (a set of eigenvectors capturing the variations in the DVFs). Three DIR algorithms were used: 1) Demons, 2) Horn‐Schunck, and 3) iterative optical flow. The motion models derived were compared using patient 4DCT scans.Results:Motion models were derived and the variations were evaluated according to three criteria: 1) the average root mean square (RMS) difference which measures the absolute difference between the components of the eigenvectors, 2) the dot product between the eigenvectors which measures the angular difference between the eigenvectors in space, and 3) the Euclidean Model Norm (EMN), which is calculated by summing the dot products of an eigenvector with the first three eigenvectors from the reference motion model in quadrature. EMN measures how well an eigenvector can be reconstructed using another motion model derived using a different DIR algorithm. Results showed that comparing to a reference motion model (derived using the Demons algorithm), the eigenvectors of the motion model derived using the iterative optical flow algorithm has smaller RMS, larger dot product, and larger EMN values than those of the motion model derived using Horn‐Schunck algorithm.Conclusion:The study showed that motion models vary depending on which DIR algorithms were used to derive them. The choice of a DIR algorithm may affect the accuracy of the resulting model, and it is important to assess the suitability of the algorithm chosen for a particular application.This project was supported, in part, through a Master Research Agreement with Varian Medical Systems, Inc, Palo Alto, CA.
SU‐C‐209‐05: Monte Carlo Model of a Prototype Backscatter X‐Ray (BSX) Imager for Projective and Selective Object‐Plane Imaging
Authors: Rolison L , Samant S , Baciak J , Jordan K 
Published: July 2016

Purpose:To develop a Monte Carlo N‐Particle (MCNP) model for the validation of a prototype backscatter x‐ray (BSX) imager, and optimization of BSX technology for medical applications, including selective object‐plane imaging.Methods:BSX is an emerging technology that represents an alternative to conventional computed tomography (CT) and projective digital radiography (DR). It employs detectors located on the same side as the incident x‐ray source, making use of backscatter and avoiding ring geometry to enclose the imaging object. Current BSX imagers suffer from low spatial resolution. A MCNP model was designed to replicate a BSX prototype used for flaw detection in industrial materials. This prototype consisted of a 1.5mm diameter 60kVp pencil beam surrounded by a ring of four 5.0cm diameter NaI scintillation detectors. The imaging phantom consisted of a 2.9cm thick aluminum plate with five 0.6cm diameter holes drilled halfway. The experimental image was created using a raster scanning motion (in 1.5mm increments).Results:A qualitative comparison between the physical and simulated images showed very good agreement with 1.5mm spatial resolution in plane perpendicular to incident x‐ray beam. The MCNP model developed the concept of radiography by selective plane detection (RSPD) for BSX, whereby specific object planes can be imaged by varying kVp. 10keV increments in mean x‐ray energy yielded 4mm thick slice resolution in the phantom. Image resolution in the MCNP model can be further increased by increasing the number of detectors, and decreasing raster step size.Conclusion:MCNP modelling was used to validate a prototype BSX imager and introduce the RSPD concept, allowing for selective object‐plane imaging. There was very good visual agreement between the experimental and MCNP imaging. Beyond optimizing system parameters for the existing prototype, new geometries can be investigated for volumetric image acquisition in medical applications.This material is based upon work supported under an Integrated University Program Graduate Fellowship sponsored by the Department of Energy Office of Nuclear Energy.
SU‐C‐209‐06: Improving X‐Ray Imaging with Computer Vision and Augmented Reality
Authors: MacDougall R.D. , Don S , Scherrer B 
Published: July 2016

Purpose:To determine the feasibility of using a computer vision algorithm and augmented reality interface to reduce repeat rates and improve consistency of image quality and patient exposure in general radiography.Methods:A prototype device, designed for use with commercially available hardware (Microsoft Kinect 2.0) capable of depth sensing and high resolution/frame rate video, was mounted to the x‐ray tube housing as part of a Philips DigitalDiagnost digital radiography room. Depth data and video was streamed to a Windows 10 PC. Proprietary software created an augmented reality interface where overlays displayed selectable information projected over real‐time video of the patient. The information displayed prior to and during x‐ray acquisition included: recognition and position of ordered body part, position of image receptor, thickness of anatomy, location of AEC cells, collimated x‐ray field, degree of patient motion and suggested x‐ray technique. Pre‐clinical data was collected in a volunteer study to validate patient thickness measurements and x‐ray images were not acquired.Results:Proprietary software correctly identified ordered body part, measured patient motion, and calculated thickness of anatomy. Pre‐clinical data demonstrated accuracy and precision of body part thickness measurement when compared with other methods (e.g. laser measurement tool). Thickness measurements provided the basis for developing a database of thickness‐based technique charts that can be automatically displayed to the technologist.Conclusion:The utilization of computer vision and commercial hardware to create an augmented reality view of the patient and imaging equipment has the potential to drastically improve the quality and safety of x‐ray imaging by reducing repeats and optimizing technique based on patient thickness.Society of Pediatric Radiology Pilot Grant; Washington University Bear Cub Fund
SU‐C‐207B‐01: A Novel Graphics Processing Units (GPU) Implementation of Discrete Wavelet Transformation
Authors: Liu A , Chen M , Jiang S , Lu W 
Published: July 2016

Purpose:To design and implement a GPU‐based discrete wavelet transformation (DWT) to be used in medical image reconstruction, image processing, and data compression. DWTs are widely used in medical physics, but the computation of DWTs is time consuming for large volumetric data. An efficient parallel implementation of DWTs is essential for many time sensitive applications, such as 4DCT.Methods:We choose Daubechies wavelet transformations as a benchmark, implementing both DWT and inverse DWT (IDWT). The reference CPU code is from “Numerical Recipes in C”. We implemented GPU‐based codes using C++ with CUDA 7.5. A GPU is specialized processors with a highly parallel structure originally designed for manipulating computer graphics. GPU computation is highly memory‐bounded. To optimize GPU memory access pattern and achieve best performance for transformation along Y‐direction, the data are transposed before and after the DWT (IDWT), which can sharply reduce computing efforts. Both CPU and GPU codes are unit‐tested and the result differences between two implementations are verified to be within rounding error. The hardware platform was a desktop with Intel Xeon E5‐1607 3.00 GHz CPU and NVIDIA Quadro K2000 GPU.Results:With the GPU implemented code, we process a medical CT image size of 512×512×256 in 0.5 seconds, which is 60 times faster than the CPU implementation. A naive non‐optimized GPU implementation by direct parallelization approaches only 10 times speedup for 2‐D and 3‐D DWT and IDWT. In comparison, the optimization of GPU memory access pattern can obtain an extra 6x speedup.Conclusion:We developed an efficient implementation of GPU‐based DWT/IDWT for medical image processing. To achieve the best performance of any medical imaging processing algorithm, developers should pay attention to memory access pattern optimization when implementing on GPU architecture.This project is supported by CPRIT grant under RP150485.
SU‐D‐BRC‐02: Application of Six Sigma Approach to Improve the Efficiency of Patient‐Specific QA in Proton Therapy
Authors: LAH J , Shin D , Manger R , Kim G 
Published: July 2016

Purpose:To show how the Six Sigma DMAIC (Define‐Measure‐Analyze‐Improve‐Control) can be used for improving and optimizing the efficiency of patient‐specific QA process by designing site‐specific range tolerances.Methods:The Six Sigma tools (process flow diagram, cause and effect, capability analysis, Pareto chart, and control chart) were utilized to determine the steps that need focus for improving the patient‐specific QA process. The patient‐specific range QA plans were selected according to 7 treatment site groups, a total of 1437 cases. The process capability index, Cpm was used to guide the tolerance design of patient site‐specific range. We also analyzed the financial impact of this project.Results:Our results suggested that the patient range measurements were non‐capable at the current tolerance level of ±1 mm in clinical proton plans. The optimized tolerances were calculated for treatment sites. Control charts for the patient QA time were constructed to compare QA time before and after the new tolerances were implemented. It is found that overall processing time was decreased by 24.3% after establishing new site‐specific range tolerances. The QA failure for whole process in proton therapy would lead up to a 46% increase in total cost. This result can also predict how costs are affected by changes in adopting the tolerance design.Conclusion:We often believe that the quality and performance of proton therapy can easily be improved by merely tightening some or all of its tolerance requirements. This can become costly, however, and it is not necessarily a guarantee of better performance. The tolerance design is not a task to be undertaken without careful thought. The Six Sigma DMAIC can be used to improve the QA process by setting optimized tolerances. When tolerance design is optimized, the quality is reasonably balanced with time and cost demands.