Manometric Biofeedback Effectiveness on Urinary Incontinence and Quality of Life: A Non-Randomized Control Trial

Directory of Open Access Journals (Sweden)

Marcos E Fernandez-Cuadros

2017-04-01

Full Text Available Objectives This study aimed at examining if a 6-session protocol of tonic-phasic exercises using manometric biofeedback (BFB is capable of improving quality of life (QoL and muscular strength in patients with urinary incontinence (UI. Methods A prospective quasi-experimental before-after study was performed on 31 patients with Urinary Incontinence (UI referred to the rehabilitation department of Santa Cristina’s University hospital, Madrid, Spain. The study was performed from January to December 2016. At initial evaluation, affiliation of data, predisposing factors, and type of UI were recorded. Patients were given lifestyle recommendations and international consultation on incontinence questionnaire short form (ICIQ-SF/ incontinence quality-of-life measure (I-QOL questionnaires/scales to be fulfilled at the beginning/end of treatment. Manometric evaluation was recorded at initial/final evaluation by MYOMED ® 932. Manometric-BFB protocol consisted of a 30-minute session of tonic/phasic exercises (15 minutes each, 2 times a week for up to 6 sessions, supervised by a physiotherapist. Results Mean age was 52 ± 12.1 years. Overall, 96.7% (n = 31 of the participants were females. Maximum and mean strength of pelvic floor contraction was 24 ± 17.72 and 4.9 ± 4.1 mmHg, and increased significantly after treatment to 35 ± 20.85 and 7.45 ± 4.92 mmHg (P < 0.01. The mean ICIQ-SF score was 9.13 ± 5.18 and decreased significantly to 6.13 ± 4.75 (P = 0.003. The mean I-QoL score increased significantly from 70.33 ± 22.12 to 81.25 ± 16.72 (P = 0.0017. The I-QoL Limiting Behaviour (LB-subscale raised from 68.38 ± 23.33 to 80 ± 16.56 (P = 0.0015; I-QoL Psychosocial Impact (PI-subscale increased from 77.43 ± 24.51 to 80 ± 17.47 (p = 0.0152; and I-QoL social embarrassment (SE-subscale incremented from 60.72 ± 22.37 to 74.37 ± 20.86 (P = 0.0007. Conclusions Manometric-BFB protocol is capable of decreasing UI and to improve QoL and manometric values

Challenges in contrast-enhanced spectral mammography interpretation: artefacts lexicon.

Science.gov (United States)

Yagil, Y; Shalmon, A; Rundstein, A; Servadio, Y; Halshtok, O; Gotlieb, M; Sklair-Levy, M

2016-05-01

To review and describe commonly encountered artefacts in contrast-enhanced spectral mammography (CESM). This retrospective study included 200 women who underwent CESM examinations for screening and diagnostic purposes. Analysis was performed on the image data sets of these women, comprising of a total of 774 subtracted images. Images were reviewed with focus on the presence of four artefacts: rim ("breast within breast"), ripple (black and white lines), axillary line, and skin-line enhancement (skin-line highlighting). Statistical cross-correlation and association with acquisition parameters (tube current, tube voltage, compression force, breast thickness, paddle size) was compared using Fisher's exact test and t-test. The rim artefact was highly common (97-99%) in every projection. The ripple artefact was increasingly more common on the oblique projections (80-82%) and found to be associated with higher breast thickness values. The axillary line artefact was detected only on oblique projections (63%) and associated with the use of a small compression paddle. The skin-line enhancement artefact was seen in 19-46% of projections. None of the artefacts interfered with image interpretation. Two main artefacts commonly seen on CESM are rim and ripple artefacts. They do not hamper with image interpretation. It is important to be aware of them and prevent misinterpretation of these artefacts as real breast pathology. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Metal artefact reduction in gemstone spectral imaging dual-energy CT with and without metal artefact reduction software

International Nuclear Information System (INIS)

Lee, Young Han; Song, Ho-Taek; Kim, Sungjun; Suh, Jin-Suck; Park, Kwan Kyu

2012-01-01

To assess the usefulness of gemstone spectral imaging (GSI) dual-energy CT (DECT) with/without metal artefact reduction software (MARs). The DECTs were performed using fast kV-switching GSI between 80 and 140 kV. The CT data were retro-reconstructed with/without MARs, by different displayed fields-of-view (DFOV), and with synthesised monochromatic energy in the range 40-140 keV. A phantom study of size and CT numbers was performed in a titanium plate and a stainless steel plate. A clinical study was performed in 26 patients with metallic hardware. All images were retrospectively reviewed in terms of the visualisation of periprosthetic regions and the severity of beam-hardening artefacts by using a five-point scale. The GSI-MARs reconstruction can markedly reduce the metal-related artefacts, and the image quality was affected by the prosthesis composition and DFOV. The spectral CT numbers of the prosthesis and periprosthetic regions showed different patterns on stainless steel and titanium plates. Dual-energy CT with GSI-MARs can reduce metal-related artefacts and improve the delineation of the prosthesis and periprosthetic region. We should be cautious when using GSI-MARs because the image quality was affected by the prosthesis composition, energy (in keV) and DFOV. The metallic composition and size should be considered in metallic imaging with GSI-MARs reconstruction. circle Metal-related artefacts can be troublesome on musculoskeletal computed tomography (CT). circle Gemstone spectral imaging (GSI) with dual-energy CT (DECT) offers a novel solution circle GSI and metallic artefact reduction software (GSI-MAR) can markedly reduce these artefacts. circle However image quality is influenced by the prosthesis composition and other parameters. circle We should be aware about potential overcorrection when using GSI-MARs. (orig.)

Metal artefact reduction for accurate tumour delineation in radiotherapy

DEFF Research Database (Denmark)

Kovacs, David Gergely; Rechner, Laura A.; Appelt, Ane L.

2018-01-01

Background and purpose: Two techniques for metal artefact reduction for computed tomography were studied in order to identify their impact on tumour delineation in radiotherapy. Materials and methods: Using specially designed phantoms containing metal implants (dental, spine and hip) as well...... delineation significantly (pmetal implant....... as patient images, we investigated the impact of two methods for metal artefact reduction on (A) the size and severity of metal artefacts and the accuracy of Hounsfield Unit (HU) representation, (B) the visual impact of metal artefacts on image quality and (C) delineation accuracy. A metal artefact reduction...

Artefacts: Minecraft meets Collaborative Interactive Evolution

DEFF Research Database (Denmark)

Patrascu, Cristinel; Risi, Sebastian

2016-01-01

Procedural content generation has shown promise in a variety of different games. In this paper we introduce a new kind of game, called Artefacts, that combines a sandbox-like environment akin to Minecraft with the ability to interactively evolve unique three-dimensional building blocks. Artefacts...

Reduction of metallic coil artefacts in computed tomography body imaging: effects of a new single-energy metal artefact reduction algorithm

Energy Technology Data Exchange (ETDEWEB)

Kidoh, Masafumi; Utsunomiya, Daisuke; Ikeda, Osamu; Tamura, Yoshitaka; Oda, Seitaro; Yuki, Hideaki; Nakaura, Takeshi; Hirai, Toshinori; Yamashita, Yasuyuki [Kumamoto University, Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto (Japan); Funama, Yoshinori [Kumamoto University, Department of Medical Physics, Faculty of Life Sciences, Kumamoto (Japan); Kawano, Takayuki [Kumamoto University Graduate School, Department of Neurosurgery, Faculty of Life Sciences Research, Kumamoto (Japan)

2016-05-15

We evaluated the effect of a single-energy metal artefact reduction (SEMAR) algorithm for metallic coil artefact reduction in body imaging. Computed tomography angiography (CTA) was performed in 30 patients with metallic coils (10 men, 20 women; mean age, 67.9 ± 11 years). Non-SEMAR images were reconstructed with iterative reconstruction alone, and SEMAR images were reconstructed with the iterative reconstruction plus SEMAR algorithms. We compared image noise around metallic coils and the maximum diameters of artefacts from coils between the non-SEMAR and SEMAR images. Two radiologists visually evaluated the metallic coil artefacts utilizing a four-point scale: 1 = extensive; 2 = strong; 3 = mild; 4 = minimal artefacts. The image noise and maximum diameters of the artefacts of the SEMAR images were significantly lower than those of the non-SEMAR images (65.1 ± 33.0 HU vs. 29.7 ± 10.3 HU; 163.9 ± 54.8 mm vs. 10.3 ± 19.0 mm, respectively; P < 0.001). Better visual scores were obtained with the SEMAR technique (3.4 ± 0.6 vs. 1.0 ± 0.0, P < 0.001). The SEMAR algorithm significantly reduced artefacts caused by metallic coils compared with the non-SEMAR algorithm. This technique can potentially increase CT performance for the evaluation of post-coil embolization complications. (orig.)

Reduction of metallic coil artefacts in computed tomography body imaging: effects of a new single-energy metal artefact reduction algorithm

International Nuclear Information System (INIS)

Kidoh, Masafumi; Utsunomiya, Daisuke; Ikeda, Osamu; Tamura, Yoshitaka; Oda, Seitaro; Yuki, Hideaki; Nakaura, Takeshi; Hirai, Toshinori; Yamashita, Yasuyuki; Funama, Yoshinori; Kawano, Takayuki

2016-01-01

We evaluated the effect of a single-energy metal artefact reduction (SEMAR) algorithm for metallic coil artefact reduction in body imaging. Computed tomography angiography (CTA) was performed in 30 patients with metallic coils (10 men, 20 women; mean age, 67.9 ± 11 years). Non-SEMAR images were reconstructed with iterative reconstruction alone, and SEMAR images were reconstructed with the iterative reconstruction plus SEMAR algorithms. We compared image noise around metallic coils and the maximum diameters of artefacts from coils between the non-SEMAR and SEMAR images. Two radiologists visually evaluated the metallic coil artefacts utilizing a four-point scale: 1 = extensive; 2 = strong; 3 = mild; 4 = minimal artefacts. The image noise and maximum diameters of the artefacts of the SEMAR images were significantly lower than those of the non-SEMAR images (65.1 ± 33.0 HU vs. 29.7 ± 10.3 HU; 163.9 ± 54.8 mm vs. 10.3 ± 19.0 mm, respectively; P < 0.001). Better visual scores were obtained with the SEMAR technique (3.4 ± 0.6 vs. 1.0 ± 0.0, P < 0.001). The SEMAR algorithm significantly reduced artefacts caused by metallic coils compared with the non-SEMAR algorithm. This technique can potentially increase CT performance for the evaluation of post-coil embolization complications. (orig.)

Multiple height calibration artefact for 3D microscopy

DEFF Research Database (Denmark)

De Chiffre, Leonardo; Carli, Lorenzo; Eriksen, Rasmus Solmer

2011-01-01

A novel artefact for calibration of the height in 3D microscopy is presented. The artefact comprises three steps having a common vertical axis, which allows z-coordinate calibration at different magnifications without requiring repositioning. The artefact is suitable for transferring traceability...... to 3D techniques at the micrometer and nanometer scale, e.g. 3D SEM, confocal microscopes etc. Two different series of samples were fabricated using EDM with three steps of 2–5–7μm, and 20–50–70μm, respectively, from a 3mm diameter carbide wire. The artefact steps were calibrated on a stylus instrument...

Neutron activation analysis of artefacts

International Nuclear Information System (INIS)

Mohd Suhaimi Hamzah; Shamsiah Abd Rahman

2004-01-01

The paper discussed the utilization of neutron activation analysis in this field. NAA, an analytical technique which analyzing the elements in the sample without any chemical treatment. It is sensitive and accurate. Archaeological objects i.e. ceramics, historical building materials, metals, etc can be analyze with this technique. The analysis results were presented in form of characterization of the artefacts in chemical profiles, which can present the information of the origin of the artefacts as well as it originality. (Author)

Experiential Role of Artefacts in Cooperative Design

NARCIS (Netherlands)

Vyas, Dhaval; Heylen, Dirk K.J.; Nijholt, Antinus; van der Veer, Gerrit C.; Caroll, J.M.

2009-01-01

The role of material artefacts in supporting distributed and co-located work practices has been well acknowledged within the HCI and CSCW research. In this paper, we show that in addition to their ecological, coordinative and organizational support, artefacts also play an ‘experiential’ role. In

Replica calibration artefacts for optical 3D scanning of micro parts

DEFF Research Database (Denmark)

De Chiffre, Leonardo; Carmignato, S.; Cantatore, Angela

2009-01-01

This work deals with development of calibration artefacts produced by using hard replica materials, achieving high quality geometrical reproduction of suitable reference artefacts, high stability, and high surface cooperativeness. An investigation was carried out using a replica material for dental...... applications to reproduce the geometry of a step artefact, a miniature step gauge, and a curve standard for optical measuring machines. The replica artefacts were calibrated using a tactile coordinate measuring machine and measured on two different optical scanners. Replication quality and applicability...... of the artefacts to verify the accuracy of optical measurements as well as thermal expansion coefficient and stability of the replica artefacts over time were documented....

Leadership identity : using artefacts (and storytelling) to discover new insights.

OpenAIRE

Watton, Emma Louisa; Parry, Ken

2016-01-01

Artefacts are used in management education to reflect upon the experiences of participants. Story-telling has a leadership influence that is long recognised in the leadership literature. However, artefacts and story-telling have not been used concurrently in leadership and management development programmes. We used artefacts combined with story-telling to help participants understand their leadership identity. Louisa’s story and artefact are the basis of this research. We found that the story...

Immediate assessment of in situ gas content using underground manometric desorbometer

Energy Technology Data Exchange (ETDEWEB)

Lunaezewski, L.W.; Mahoney, M.R. [Lunagas Pty. Ltd., Newcastle, NSW (Australia)

1995-12-31

An underground assessment of gas content (within 30 minutes) can be used as a complementary method for the immediate establishment of the magnitudes of in situ gas content at a distance of 5 to 6 metres ahead of a heading face. The indirect method of in situ gas content measurement, using a manometric desorbometer, can be used to establish the direct relationship between underground desorbometer readings and corresponding in situ gas content values for a selected coal seam. 3 refs., 3 figs.

Investigating effects of different artefact types on motor imagery BCI

DEFF Research Database (Denmark)

Frølich, Laura; Winkler, Irene; Muller, Klaus-Robert

2015-01-01

Artefacts in recordings of the electroencephalogram (EEG) are a common problem in Brain-Computer Interfaces (BCIs). Artefacts make it difficult to calibrate from training sessions, resulting in low test performance, or lead to artificially high performance when unintentionally used for BCI control...... that muscle, but not ocular, artefacts adversely affect BCI performance when all 119 EEG channels are used. Artefacts have little influence when using 48 centrally located EEG channels in a configuration previously found to be optimal....

Indigenous african artefacts: Can they serve as tangible programming objects?

CSIR Research Space (South Africa)

Smith, Andrew C

2010-05-01

Full Text Available , African artefacts, Interaction design. 1. Introduction The aim of our research is to investigate the possible use of physical artefacts as tangible programming objects with the purpose of instilling an interest in programming amongst regional tribes... in Africa. Physical artefacts are hand-crafted objects made by community members. We envisage a simple computing system that derives its input from the manipulation of artefacts as opposed to the use of a keyboard and mouse. In order to do so...

Organisational learning is crystallised into artefacts

DEFF Research Database (Denmark)

Bertelsen, Olav Wedege

1996-01-01

In this note I understand organisational learning in terms of manifest crystallisation of collective experience into artefacts, and I attempt to integrate an engineering and an emancipatory perspective. A Danish music festival serves as an example.......In this note I understand organisational learning in terms of manifest crystallisation of collective experience into artefacts, and I attempt to integrate an engineering and an emancipatory perspective. A Danish music festival serves as an example....

Assessing MRI susceptibility artefact through an indicator of image distortion

Directory of Open Access Journals (Sweden)

Illanes Alfredo

2016-09-01

Full Text Available Susceptibility artefacts in magnetic resonance imaging (MRI caused by medical devices can result in a severe degradation of the MR image quality. The quantification of susceptibility artefacts is regulated by the ASTM standard which defines a manual method to assess the size of an artefact. This means that the estimated artefact size can be user dependent. To cope with this problem, we propose an algorithm to automatically quantify the size of such susceptibility artefacts. The algorithm is based on the analysis of a 3D surface generated from the 2D MR images. The results obtained by the automatic algorithm were compared to the manual measurements performed by study participants. The results show that the automatic and manual measurements follow the same trend. The clear advantage of the automated algorithm is the absence of the inter- and intra-observer variability. In addition, the algorithm also detects the slice containing the largest artefact which was not the case for the manual measurements.

Artefacts that talk

DEFF Research Database (Denmark)

Hasse, Cathrine

2013-01-01

The article takes up the notion of artefacts as tools and signs and discusses how socially assistive robots impact professional work life and professional identities as multistable active change agents. It argues for a multistable understanding of tools as signs, building on a combination of post...

The materiality of materials and artefacts used in science classrooms

DEFF Research Database (Denmark)

Cowie, Bronwen; Otrel-Cass, Kathrin; Moreland, Judy

Material objects and artefacts receive limited attention in science education (Roehl, 2012) though they shape emerging interactions. This is surprising given science has material and a social dimensions (Pickering, 1995) whereby new knowledge develops as a consensus explanation of natural phenomena...... that is mediated significantly through materials and instruments used. Here we outline the ways teachers deployed material objects and artefacts by identifying their materiality to provide scenarios and resources (Roth, 2005) for interactions. Theoretical framework We use Ingold's (2011) distinction between...... materials as natural objects in this world and artefacts as manmade objects. We are aware that in a classroom material objects and artefacts shape, and are shaped by classroom practice through the way they selectively present scientific explanations. However, materials and artefacts have no intrinsic...

3D artefact for concurrent scale calibration in Computed Tomography

DEFF Research Database (Denmark)

Stolfi, Alessandro; De Chiffre, Leonardo

2016-01-01

A novel artefact for calibration of the scale in 3D X-ray Computed Tomography (CT) is presented. The artefact comprises a carbon fibre tubular structure on which a number of reference ruby spheres are glued. The artefact is positioned and scanned together with the workpiece inside the CT scanner...

Possible artefacts in thin layer chromatography of tritium-labelled hydrocortisone

International Nuclear Information System (INIS)

Sofronie, E.

1982-12-01

Artefacts appearing in thin layer chromatography of tritium labelled hydrocortisone are reported. Evidences are presented that these artefacts cause misleading results concerning radiocheemical purity determiniation. Finally, it is reported a rapid and efficient chromatographic technique allowing the elimination of these artefacts and obtaining of an accurate value for radiochemical purity. (author)

Artefact specification, design, and production as a process of communication

DEFF Research Database (Denmark)

Galle, Per

1999-01-01

about communication as literal ‘transmission’ or ‘sharing’ of ideas. It is then explained how the initial artefact specification, the design representation, and ultimately the artefact itself can all be seen as symbolic expressions of ideas that are communicated, and it is shown how the conditions...... for the success of communication carry over to the artefact production process. The purpose of the analysis is to provide a conceptual background for the study of various aspects of artefact production, such as design, or the development of computer-based tools for collaborative design, product modelling...

Esophageal motility disorders-Symptomatic and manometric spectrum in Punjab, northern India.

Science.gov (United States)

Goyal, Omesh; Bansal, Monika; Sood, Ajit

2017-05-01

Data on the spectrum of esophageal motility disorders in Indian population are scarce. We aimed to study the symptomatic and manometric profile of patients with suspected esophageal motility disorders. Consecutive patients with esophageal symptoms who underwent esophageal high-resolution manometry (HRM) from January 2010 to December 2014 were included in this retrospective analysis of prospectively acquired data. HRM was performed with 22-channel water-perfusion system and patients classified using Chicago classification v3.0. Of the 401 patients studied [median age 43 (18-85) years; 61% males], 217 presented with dysphagia, 157 with predominant retrosternal discomfort and 27 with predominant regurgitation. Among patients with dysphagia, 43.8% had ineffective esophageal motility [IEM], 26.3% had achalasia cardia [AC], 6.9% had distal esophageal spasm [DES] and 19.4% had normal manometry [NM]. Among patients with retrosternal discomfort, 42.7% had IEM, 5.7% had AC, 4.5% had DES and 42% had NM. AC was significantly more common among patients presenting with dysphagia compared to those with retrosternal discomfort [pdysphagia [pdysphagia, more frequent bolus obstruction and more weight loss compared to those with IEM or NM [pDysphagia was the commonest presenting symptom followed by retrosternal discomfort. Ineffective esophageal motility (not achalasia cardia) was the commonest manometric finding both among patients with dysphagia and retrosternal discomfort. This study highlights the high prevalence of IEM among patients with esophageal symptoms, which can present with dysphagia or retrosternal discomfort due to poor bolus transit.

Metal artefact reduction in MRI at both 1.5 and 3.0 T using slice encoding for metal artefact correction and view angle tilting

Science.gov (United States)

Reichert, M; Morelli, J N; Nittka, M; Attenberger, U; Runge, V M

2015-01-01

Objective: To compare metal artefact reduction in MRI at both 3.0 T and 1.5 T using different sequence strategies. Methods: Metal implants of stainless steel screw and plate within agarose phantoms and tissue specimens as well as three patients with implants were imaged at both 1.5 T and 3.0 T, using view angle tilting (VAT), slice encoding for metal artefact correction with VAT (SEMAC-VAT) and conventional sequence. Artefact reduction in agarose phantoms was quantitatively assessed by artefact volume measurements. Blinded reads were conducted in tissue specimen and human imaging, with respect to artefact size, distortion, blurring and overall image quality. Wilcoxon and Friedman tests for multiple comparisons and intraclass correlation coefficient (ICC) for interobserver agreement were performed with a significant level of p 3.0 T (p 3.0 T. Advances in knowledge: The feasibility of metal artefact reduction with SEMAC-VAT was demonstrated at 3.0-T MR. SEMAC-VAT significantly reduced metal artefacts at both 1.5 and 3.0 T. SEMAC-VAT allowed for better visualization of the tissue structures adjacent to the metal implants. SEMAC-VAT produced consistently better image quality in both tissue specimen and human imaging. PMID:25613398

Reduction of ring artefacts in high resolution micro-CT reconstructions

International Nuclear Information System (INIS)

Sijbers, Jan; Postnov, Andrei

2004-01-01

High resolution micro-CT images are often corrupted by ring artefacts, prohibiting quantitative analysis and hampering post processing. Removing or at least significantly reducing such artefacts is indispensable. However, since micro-CT systems are pushed to the extremes in the quest for the ultimate spatial resolution, ring artefacts can hardly be avoided. Moreover, as opposed to clinical CT systems, conventional correction schemes such as flat-field correction do not lead to satisfactory results. Therefore, in this note a simple but efficient and fast post processing method is proposed that effectively reduces ring artefacts in reconstructed μ-CT images. (note)

Dosimetric Evaluation of Metal Artefact Reduction using Metal Artefact Reduction (MAR) Algorithm and Dual-energy Computed Tomography (CT) Method

Science.gov (United States)

Laguda, Edcer Jerecho

Purpose: Computed Tomography (CT) is one of the standard diagnostic imaging modalities for the evaluation of a patient's medical condition. In comparison to other imaging modalities such as Magnetic Resonance Imaging (MRI), CT is a fast acquisition imaging device with higher spatial resolution and higher contrast-to-noise ratio (CNR) for bony structures. CT images are presented through a gray scale of independent values in Hounsfield units (HU). High HU-valued materials represent higher density. High density materials, such as metal, tend to erroneously increase the HU values around it due to reconstruction software limitations. This problem of increased HU values due to metal presence is referred to as metal artefacts. Hip prostheses, dental fillings, aneurysm clips, and spinal clips are a few examples of metal objects that are of clinical relevance. These implants create artefacts such as beam hardening and photon starvation that distort CT images and degrade image quality. This is of great significance because the distortions may cause improper evaluation of images and inaccurate dose calculation in the treatment planning system. Different algorithms are being developed to reduce these artefacts for better image quality for both diagnostic and therapeutic purposes. However, very limited information is available about the effect of artefact correction on dose calculation accuracy. This research study evaluates the dosimetric effect of metal artefact reduction algorithms on severe artefacts on CT images. This study uses Gemstone Spectral Imaging (GSI)-based MAR algorithm, projection-based Metal Artefact Reduction (MAR) algorithm, and the Dual-Energy method. Materials and Methods: The Gemstone Spectral Imaging (GSI)-based and SMART Metal Artefact Reduction (MAR) algorithms are metal artefact reduction protocols embedded in two different CT scanner models by General Electric (GE), and the Dual-Energy Imaging Method was developed at Duke University. All three

Ringing Artefact Reduction By An Efficient Likelihood Improvement Method

Science.gov (United States)

Fuderer, Miha

1989-10-01

In MR imaging, the extent of the acquired spatial frequencies of the object is necessarily finite. The resulting image shows artefacts caused by "truncation" of its Fourier components. These are known as Gibbs artefacts or ringing artefacts. These artefacts are particularly. visible when the time-saving reduced acquisition method is used, say, when scanning only the lowest 70% of the 256 data lines. Filtering the data results in loss of resolution. A method is described that estimates the high frequency data from the low-frequency data lines, with the likelihood of the image as criterion. It is a computationally very efficient method, since it requires practically only two extra Fourier transforms, in addition to the normal. reconstruction. The results of this method on MR images of human subjects are promising. Evaluations on a 70% acquisition image show about 20% decrease of the error energy after processing. "Error energy" is defined as the total power of the difference to a 256-data-lines reference image. The elimination of ringing artefacts then appears almost complete..

Reduction of artefacts due to missing projections using OSEM

International Nuclear Information System (INIS)

Hutton, B.F.; Kyme, A.; Choong, K.

2002-01-01

Full text: It is well recognised that missing or corrupted projections can result in artefacts. This occasionally occurs due to errors in data transfer from acquisition memory to disk. A possible approach for reducing these artefacts was investigated, Using ordered subsets expectation maximization (OSEM) the iterative reconstruction proceeds by progressively including additional projections until a single iteration is complete. Clinically useful results can be obtained using a small subset size in a single iteration. Stopping prior to the complete iteration so as to avoid inclusion of missing or corrupted data should provide a 'partial' reconstruction with minimal artefacts. To test this hypothesis projections were selectively removed from a complete data set (2, 4, 8, 12 adjacent projections) and reconstructions were performed using both filtered back projection (FBP) and OSEM. To maintain a constant number of sub-iterations in OSEM an equal number of duplicate projections were substituted for the missing projections. Both 180 and 360 degrees reconstructions with missing data were compared with reconstruction for the complete data using sum of absolute differences. Results indicate that missing data causes artefacts for both FBP and OSEM however the severity of artefacts is significantly reduced using OSEM. The effect of missing data is generally greater for 180 degrees acquisition. OSEM is recommended for minimising reconstruction artefacts due to missing projections. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc

Clinical, endoscopic and manometric features of the primary motor disorders of the esophagus.

Science.gov (United States)

Martinez, Júlio César; Lima, Gustavo Rosa de Almeida; Silva, Diego Henrique; Duarte, Alexandre Ferreira; Novo, Neil Ferreira; da Silva, Ernesto Carlos; Pinto, Pérsio Campos Correia; Maia, Alexandre Moreira

2015-01-01

Significant incidence, diagnostic difficulties, clinical relevance and therapeutic efficacy associated with the small number of publications on the primary esophageal motor disorders, motivated the present study. To determine the manometric prevalence of these disorders and correlate them to the endoscopic and clinical findings. A retrospective study of 2614 patients, being 1529 (58.49%) women and 1085 (41.51%) men. From 299 manometric examinations diagnosed with primary esophageal motor disorder, were sought-clinical data (heartburn, regurgitation, dysphagia, odynophagia, non-cardiac chest pain, pharyngeal globe and extra-esophageal symptoms) and/or endoscopic (hiatal hernia, erosive esophagitis, food waste) that motivated the performance of manometry. Were found 49 cases of achalasia, 73 diffuse spasm, 89 nutcracker esophagus, 82 ineffective esophageal motility, and six lower esophageal sphincter hypertension. In relation to the correlations, it was observed that in 119 patients clinical conditions were associated with dysphagia, found in achalasia more than in other conditions; in relationship between endoscopic findings and clinical conditions there was no statistical significance between data. The clinical and endoscopic findings have little value in the characterization of the primary motor disorders of the esophagus, showing even more the need for manometry, particularly in the preoperative period of gastroesophageal reflux disease.

Basic artefacts of diagnostic imaging by the magnetic resonance method

International Nuclear Information System (INIS)

Vitak, T.; Seidl, Z.; Obenberger, J.; Vaneckova, M.; Danes, J.; Krasensky, J.; Peterkova, V

2000-01-01

Artefacts in diagnostic imaging are defined as a geometric or anatomic misrepresentation of the reality by the image formed. The article deals with artefacts due to field and frequency shifts, in particular due to the water-fat chemical shift and due to magnetic susceptibility. The physical nature of the artefacts is explained and their diagnostic significance is discussed. (P.A.)

GIS as an Artefact in Geography Education: Some Future Challenges

DEFF Research Database (Denmark)

Madsen, Lene Møller; Winsløw, Carl

2007-01-01

Geographers have always used a variety of physical artefacts e.g. a pluviometer, a map, or a globe as tools to perform their profession. Each of these artefacts has in different ways shaped our ways of being and becoming geographers. Not only have they shaped how we learn but also what we learn. ...... this artefact offers to education and teaching....

Image quality and artefact generation post-cerebral aneurysm clipping using a 64-row multislice computer tomography angiography (MSCTA) technology: A retrospective study and review of the literature.

Science.gov (United States)

Zachenhofer, Iris; Cejna, Manfred; Schuster, Antonius; Donat, Markus; Roessler, Karl

2010-06-01

Computed tomography angiography (CTA) is a time and cost saving investigation for postoperative evaluation of clipped cerebral aneurysm patients. A retrospective study was conducted to analyse image quality and artefact generation due to implanted aneurysm clips using a new technology. MSCTA was performed pre- and postoperatively using a Philips Brilliance 64-detector-row CT scanner. Altogether, 32 clipping sites were analysed in 27 patients (11 female and 16 male, mean ages 52a, from 24 to 72 years). Clip number per aneurysm was 2.3 mean (from 1 to 4), 54 clips were made of titanium alloy and 5 of cobalt alloy. Altogether, image quality was rated 1.8 mean, using a scale from 1 (very good) to 5 (unserviceable) and clip artefacts were rated 2.4 mean, using a 5 point rating scale (1 no artefacts, 5 unserviceable due to artefacts). A significant loss of image quality and rise of artefacts was found when using cobalt alloy clips (1.4 versus 4.2 and 2.1 versus 4.0). In 72% of all investigations, an excellent image quality was found. Excluding the cobalt clip group, 85% of scans showed excellent image quality. Artefacts were absent or minimal (grade 1 or 2) in 69% of all investigations and in 81% in the pure titanium clip group. In 64-row MSCTA of good image quality with low artefacts, it was possible to detect small aneurysm remnants of 2mm size in individual patients. By using titanium alloy clips, in our study up to 85% of postoperative CTA images were of excellent quality with absent or minimal artefacts in 81% and seem adequate to detect small aneurysm remnants. Copyright 2010 Elsevier B.V. All rights reserved.

On what is made : instruments, products and natural kinds of artefacts

NARCIS (Netherlands)

Houkes, W.N.; Vermaas, P.E.; Franssen, M.; Kroes, P.; Reydon, T.A.C.; Vermaas, P.E.

2014-01-01

Debates in the metaphysics of artefacts typically start from the observation that technical artefacts result from intentional production and then focus immediately on the issue whether this ‘mind-dependence’ undermines claims that artefacts exist or come in natural or real kinds. We aim to add

Age and gender affect likely manometric diagnosis: Audit of a tertiary referral hospital clinical esophageal manometry service.

Science.gov (United States)

Andrews, Jane M; Heddle, Richard; Hebbard, Geoffrey S; Checklin, Helen; Besanko, Laura; Fraser, Robert J

2009-01-01

Awareness of patient demographics, common diagnoses and associations between these may improve the use and interpretation of manometric investigations. The aim of the present study therefore was to determine whether age and/or gender affect manometric diagnosis in a clinical motility service. An audit of all 452 clinical manometry reports issued from December 2003 to July 2005 with respect to age, gender and diagnosis was carried out. Patients were divided by age (17-24 years n = 14, 25-44 years n = 87, 45-64 years n = 216 and >or=65 years n = 135), and gender and data compared using contingency tables. Women were more commonly referred overall (59%) and in each age bracket except motor problems P = 0.01. With aging, normal motor function became less common (P = 0.013), with non-specific motor disorder, ineffective/hypotensive peristalsis and 'achalasia-like' conditions each more common (individual P = NS). Increasing age showed a trend for increased spastic motor disorders (P = 0.06). Gender did not, however, influence whether motility was abnormal (P = 0.5), spastic (P = 0.7) or whether a non-specific motor disorder was present (P = 0.1). In the total cohort, the principal manometric diagnoses were: non-specific motor disorder 33%, normal motility 29%, low basal lower esophageal sphincter pressure 18%, hypotensive/ineffective peristalsis 10%, achalasia/achalasia-like 6%, diffuse esophageal spasm 3% and other 1%. Aging leads to increasing esophageal motor abnormalities. Men and women have similar rates of dysfunction, although 'low-pressure problems' were more common in men.

Treatment choices and outcomes of patients with manometrically diagnosed achalasia.

Science.gov (United States)

Yeung, J C; Finley, C; Hanna, W C; Miller, L; Ferri, L; Urbach, D R; Darling, G E

2016-07-01

This prospective population-based study was designed to evaluate treatment choices in patients with new manometrically diagnosed achalasia and their outcomes. Patients referred to the esophageal function laboratory were enrolled after a new manometric diagnosis of achalasia. Patients completed an initial achalasia symptom score validated questionnaire on their symptom severity, duration, treatment pre-diagnosis and Medical Outcomes Study 36-item Short-Form (SF-36) survey. Treatment decisions were made by the referring physician and the patient. Follow-up questionnaires were completed every 3 months for 1 year. Patients who chose not to undergo treatment at 1-year follow-up completed another questionnaire after 5 years. Between January 2004 and January 2005, 83 of 124 eligible patients were enrolled. Heller myotomy was performed on 31 patients, three patients received botulinum toxin injections, and 25 patients received 29 pneumatic balloon dilatations. Twenty-four patients chose to receive no treatment. Following treatment, patients treated with surgery, dilatation and botulinum toxin had an average improvement in achalasia symptom score of 23 +/- 12.2, 17 +/- 10.9, and 9 +/- 14, respectively. Patients receiving no treatment had worsening symptoms with a symptom score change of -3.5 +/- 11.4. Surgery and dilatation resulted in significant improvement (P treatment. In univariate logistic regression, symptom severity score (odds ratio [OR] 1.04, 95% confidence interval [CI] 1.00 to 1.08), sphincter tone (OR 1.04, 95% CI 1.00 to 1.09), difficulty swallowing liquids (OR 3.21, 95% 1.15 to 8.99), waking from sleep (OR 2.75, 95% 1.00 to 7.61), and weight loss (OR 5.99, 95% CI 1.93 to 18.58) were all significant in predicting that patients would select treatment. In the multivariate analysis, older age (OR 1.05, 95% CI 1.01 to 1.09) and weight loss (OR 3.91, 95% CI 1.02 to 15.2) were statistically significant for undergoing treatment. At 5 years, five (21%) of those who

Determination of equilibration kinetics of oxide electrode materials using a manometric method

International Nuclear Information System (INIS)

Badwal, S.P.S.; Jiang, S.P.; Love, J.; Nowotny, J.; Rekas, M.

1998-01-01

The gas/solid equilibration kinetics for electrode oxide materials, such as (La 0.8 Sr 0.2 )MnO 3 , using a manometric method, was determined. The reaction kinetics between oxygen and the oxide material was monitored using the measurements of the P(O 2 ) changes during isothermic experiments of oxidation and reduction. The procedure of the determination will be described and relevant kinetic equations was derived. The equilibration kinetic data obtained can be used to determine the chemical diffusion coefficient. Copyright (1998) Australasian Ceramic Society

Emergent Artefacts of Ethnography and Processual Engagements of design

DEFF Research Database (Denmark)

Wallace, Jamie

2012-01-01

Relating to processes of design and creativity, the use of artefacts are contrasted between two different disciplines. Pointing to possible challenges, the study considers how collaborative innovation depends upon the interplay between entwined and emergent artefact worlds and their related skill...

Artefacts and Troubleshooting. Appendix I

Energy Technology Data Exchange (ETDEWEB)

Busemann Sokole, E. [Department of Nuclear Medicine, Academic Medical Center, Amsterdam (Netherlands); Forwood, N. J. [Department of Nuclear Medicine, Royal North Shore Hospital, Sydney (Australia)

2014-12-15

Troubleshooting refers to the process of recognizing and identifying the cause of an artefact, a malfunction or a problem in an instrument. The problem could be immediately obvious, for example, the instrument does not work at all or a particular component stops working (such as the computer, the mechanism for whole body scanning or the automatic mechanism for collimator exchange). The malfunction could also be less obvious, and be recognized only by an abnormality in the expected result (such as the pattern formed by a defective photomultiplier tube (PMT) in the gamma camera clinical or quality control (QC) image or an unexpected calibration result in a radionuclide dose calibrator). Such an abnormality is generally referred to as an artefact, in particular, when observed in images.

Explicating the Sustainable Design of Technical Artefacts

DEFF Research Database (Denmark)

Vissonova, Karina

2016-01-01

afforded by the properties of artefacts. The study is a conceptual analysis and as such belongs to the field of epistemology of design. It offers three contributions to the design discipline: (1) a proposition of the definition of the sustainable design kind; (2) a proposition of the concept of technical......Sustainable design of technical artefacts is referred to as if it were a kind of design with some specific characteristics. However, in design research and practice alike, there appears to be a lack of shared conceptions of what such a design might entail. Furthermore, we have no clear grounds...... for evaluating what makes the sustainable design solutions permissible. The lack of shared conceptions is largely due to ambiguities associated with the notion of sustainability. In response to these challenges, the aim of my study is to offer a definition of sustainable design of technical artefacts. I argue...

Importancia de la Manometría Anorrectalen la Infancia

Directory of Open Access Journals (Sweden)

Daisy Naranjo Hernández

1999-09-01

Full Text Available RESUMEN Al registrar cambios de presión en órganos musculares huecos, el estudio manométrico anorrectal ha permitido llegar a conclusiones acerca del mecanismo de continencia anorrectal, la función esfinteriana y la sensación rectal. Se utilizó el método de catéteres perfundidos y balón intrarrectal para el estímulo por distensión. Se estudiaron 340 pacientes, 214 masculinos y 126 femeninos, con una edad promedio de 6,5 años. Se formaron 3 grupos: I. Constipación crónica, II. Crónica más encopresis y III. Incontinencia anal. Entre las variables manométricas que se estudiaron: presencia o no del reflejo rectoanal inhibitorio inducido (RRII, presión de reposo, longitud, tanto por ciento de relajación del mismo y volumen crítico capaz de desencadenar respuesta esfinteriana. Se realizó estudio de colon por enema y se halló mayor correlación entre megacolon radiográfico y el mayor porcentaje de ausencia manométrica del RRAI. El grupo II mostró mayor valor de presión basal del EAI con un menor tanto por ciento de relajación y un mayor número de casos con ausencia del RRAI. En el grupo III se obtuvo el valor más bajo de presión basal del EAI mayor por ciento de relajación y mayor número de casos con ausencia del EAI. Se demuestra la importancia del estudio en el manejo integral del niño con afecciones anorrectales, el que fue indispensable en el diagnóstico de la enfermedad de Hirschprung. Su empleo se recomienda en todos los servicios de Gastroenterología Pediátrica.On registering pressure changes in the muscular hollow organs, the anorectal manometric study has allowed to reach conclusions about the mechanism of anorectal continence, the sphincteral function and the anorectal sensation. The method of perfused catheters and intrarectal balloon was used to attain the stimulus by distention. 340 patients, 214 males and 126 females with an average age of 6.5 years old, were studied. Patients were divided into 3 groups

X-ray CT high-density artefact suppression in the presence of bones

Energy Technology Data Exchange (ETDEWEB)

Wei Jikun [School of Health Sciences, 550 Stadium Mall Drive, West Lafayette, IN 47907-2051 (United States); Chen Laigao [BioImaging Center of Emphasis, Pfizer Global Research and Development, 2800 Plymouth RD, Ann Arbor, MI 48105 (United States); Sandison, George A [School of Health Sciences, 550 Stadium Mall Drive, West Lafayette, IN 47907-2051 (United States); Liang Yun [Department of Radiology, Indiana University Medical School, Indianapolis, IN 46202 (United States); Xu, Lisa X [School of Mechanical Engineering, 585 Purdue Mall, West Lafayette, IN 47907-2040 (United States)

2004-12-21

This paper presents a novel method of reducing x-ray CT high-density artefacts generated by metal objects when abundant bone structures are present in the region of interest. This method has an advantage over previously proposed methods since it heavily suppresses the metal artefacts without introducing extra bone artefacts. The method of suppression requires that bone pixels are isolated and segmented by thresholding. Then artificial CT numbers are assigned to the bone pixels so that their projection profiles are smooth and thus can be properly simulated by a polynomial interpolation. The projection profile of the metal object is then removed to fully suppress the artefacts. The resulting processed profile is fed to a reconstruction routine and the previously preserved bone pixels added back. The new method utilizes two important features of the CT image with metal artefacts: (a) metal and bone pixels are not severely affected by the high-density artefacts and (b) the high-density artefacts can be located in specific projection channels in the profile domain, although they are spread out in the image domain. This suppression method solves the problem of CT image artefacts arising from metal objects in the body. It has the potential to greatly improve diagnostic CT imaging in the presence of these objects and treatment planning that utilizes CT for patients with metal applicators (e.g., brachytherapy for cervix cancer and prostate cryotherapy)

X-ray CT high-density artefact suppression in the presence of bones

International Nuclear Information System (INIS)

Wei Jikun; Chen Laigao; Sandison, George A; Liang Yun; Xu, Lisa X

2004-01-01

This paper presents a novel method of reducing x-ray CT high-density artefacts generated by metal objects when abundant bone structures are present in the region of interest. This method has an advantage over previously proposed methods since it heavily suppresses the metal artefacts without introducing extra bone artefacts. The method of suppression requires that bone pixels are isolated and segmented by thresholding. Then artificial CT numbers are assigned to the bone pixels so that their projection profiles are smooth and thus can be properly simulated by a polynomial interpolation. The projection profile of the metal object is then removed to fully suppress the artefacts. The resulting processed profile is fed to a reconstruction routine and the previously preserved bone pixels added back. The new method utilizes two important features of the CT image with metal artefacts: (a) metal and bone pixels are not severely affected by the high-density artefacts and (b) the high-density artefacts can be located in specific projection channels in the profile domain, although they are spread out in the image domain. This suppression method solves the problem of CT image artefacts arising from metal objects in the body. It has the potential to greatly improve diagnostic CT imaging in the presence of these objects and treatment planning that utilizes CT for patients with metal applicators (e.g., brachytherapy for cervix cancer and prostate cryotherapy)

Radiocarbon dating of iron artefacts

Energy Technology Data Exchange (ETDEWEB)

Cresswell, R. [Australian National Univ., Canberra, ACT (Australia). Dept. of Nuclear Physics

1997-12-31

Iron artefacts are generally dated by association or on stylistic grounds. This may not give a true indication of the date of manufacture, or may not be possible if the piece is out of context, ambiguous in style, or a copy. Obtaining a direct date on the artefact would be preferable. During the processes of manufacture, carbon is incorporated into the iron from the fuel source. If the fuel is of a material containing contemporaneous carbon, i.e. has an ambient radiocarbon signature, e.g. charcoal, then we may reliably radiocarbon date the artefact by extracting this carbon. Care must be taken, however, to ensure that re-working has not introduced multiple sources of carbon that would give an erroneous date. Detailed chemical analysis must precede radiocarbon analysis. Sample size is determined by carbon content, and before the advent of accelerator mass spectrometry, several tens of grams of carbon were required for radiocarbon dating (van der Merwe, 1969), prohibiting this method except for high-carbon cast-irons and bulk samples, e.g. caches of nails. AMS permits the analysis of sub-gram pieces of iron (Cresswell, 1991), thereby permitting the analysis of museum pieces with only minimal loss of material, and small fragments of iron recovered from archaeological sites. A few examples are given to illustrate these points. Paper no. 41; Extended abstract. 6 refs.

Radiocarbon dating of iron artefacts

International Nuclear Information System (INIS)

Cresswell, R.

1997-01-01

Iron artefacts are generally dated by association or on stylistic grounds. This may not give a true indication of the date of manufacture, or may not be possible if the piece is out of context, ambiguous in style, or a copy. Obtaining a direct date on the artefact would be preferable. During the processes of manufacture, carbon is incorporated into the iron from the fuel source. If the fuel is of a material containing contemporaneous carbon, i.e. has an ambient radiocarbon signature, e.g. charcoal, then we may reliably radiocarbon date the artefact by extracting this carbon. Care must be taken, however, to ensure that re-working has not introduced multiple sources of carbon that would give an erroneous date. Detailed chemical analysis must precede radiocarbon analysis. Sample size is determined by carbon content, and before the advent of accelerator mass spectrometry, several tens of grams of carbon were required for radiocarbon dating (van der Merwe, 1969), prohibiting this method except for high-carbon cast-irons and bulk samples, e.g. caches of nails. AMS permits the analysis of sub-gram pieces of iron (Cresswell, 1991), thereby permitting the analysis of museum pieces with only minimal loss of material, and small fragments of iron recovered from archaeological sites. A few examples are given to illustrate these points

The effects of misinterpretation of an artefact on multidetector row CT scans in children

Energy Technology Data Exchange (ETDEWEB)

Du Plessis, Anne-Marie; Theron, Salomine; Andronikou, Savvas [University of Stellenbosch, Radiology Department, Tygerberg Hospital, Cape Town (South Africa)

2009-02-15

Artefacts reflect problems with radiographic technique rather than true pathology. These may be misinterpreted as pathology with serious consequences. An artefact caused such problems in one paediatric imaging department. To determine the incidence, and consequences of misinterpretation, of a CT artefact in a paediatric imaging department. A retrospective review of images and reports of paediatric CT scans over a set period with a known artefact was performed. Reports were correlated with reviewers' evaluation of the presence of artefact and reviewed for correct identification of artefact, misinterpretation as pathology, and action taken as a result. A total of 74 CT scans had been performed over the study period and an artefact detected by reviewers on 32 (43%). Six (18.75%) of these were misinterpreted as pathology, of which three (9.4%) were reported as tuberculous granulomas, two (6.2%) as haemorrhages and one (3.1%) as an unknown hyperdensity. Two patients (6.2%) had subsequent MRI studies performed, and treatment for tuberculosis was continued in one patient (3.1%). No initial report identified the artefact. One-fifth of the scans with the artefact were misinterpreted as pathology and half of these misinterpretations led to further action. Artefacts result in false diagnoses and unnecessary investigations; vigilance is needed. (orig.)

Partial volume and aliasing artefacts in helical cone-beam CT

International Nuclear Information System (INIS)

Zou Yu; Sidky, Emil Y; Pan, Xiaochuan

2004-01-01

A generalization of the quasi-exact algorithms of Kudo et al (2000 IEEE Trans. Med. Imaging 19 902-21) is developed that allows for data acquisition in a 'practical' frame for clinical diagnostic helical, cone-beam computed tomography (CT). The algorithm is investigated using data that model nonlinear partial volume averaging. This investigation leads to an understanding of aliasing artefacts in helical, cone-beam CT image reconstruction. An ad hoc scheme is proposed to mitigate artefacts due to the nonlinear partial volume and aliasing artefacts

Manometric and clinical analysis of patients with Achalasia in Iran

Directory of Open Access Journals (Sweden)

Montazeri Q

1999-09-01

Full Text Available Seventy-one patients with achalasia were studied. They were 2-29 years old. Dysphagia to solid food was the main presenting symptom (100 percent. Reliable and persistent manometric findings were absence of normal contraction waves in association with the presence of low amplitudes simultaneous waves in all cases. In vigorous achalasia, weight loss (P=0.001, dysphagia (P=0.012 and LES pressures (P=0.01 were significantly different in comparison to classic achalasia. Manometry was done in 18 patients who were treated with pneumatic dilation. LES pressure (P=0.003 and esophageal basal pressures were significantly dropped one month after pneumatic dilation (P=0.01. Normal contraction wave did not appeare in any of treated cases.

The role of action knowledge in the comprehension of artefacts - a PET study

DEFF Research Database (Denmark)

Gerlach, Christian; Law, Ian; Gade, Anders

2002-01-01

and two naming tasks divided by category (natural objects vs artefacts). The left PMv (BA 6/44) was more activated by the categorization task for artefacts than by the categorization task for natural objects and the naming task for artefacts. However, the left PMv was not associated with the contrast......Activation of the left ventral premotor cortex (PMv) has in previous imaging studies been associated with the processing of visually presented artefacts. It has been suggested that this activation reflects processing of action knowledge and that action knowledge contributes to the comprehension...... of artefacts. The purpose of the present study was to test whether activation of the left PMv is common for all tasks involving the comprehension of artefacts or whether it is task specific. This was done by comparing performance and regional cerebral blood flow (rCBF) associated with two categorization tasks...

Eye-lens bismuth shielding in paediatric head CT: artefact evaluation and reduction

International Nuclear Information System (INIS)

Raissaki, Maria; Perisinakis, Kostas; Damilakis, John; Gourtsoyiannis, Nicholas

2010-01-01

CT scans of the brain, sinuses and petrous bones performed as the initial imaging test for a variety of indications have the potential to expose the eye-lens, considered among the most radiosensitive human tissues, to a radiation dose. There are several studies in adults discussing the reduction of orbital dose resulting from the use of commercially available bismuth-impregnated latex shields during CT examinations of the head. To evaluate bismuth shielding-induced artefacts and to provide suggestions for optimal eye-lens shielding in paediatric head CT. A bismuth shield was placed over the eyelids of 60 consecutive children undergoing head CT. Images were assessed for the presence and severity of artefacts with regard to eye-shield distance and shield wrinkling. An anthropomorphic paediatric phantom and thermoluminescence dosimeters (TLDs) were used to study the effect of eye lens-to-shield distance on shielding efficiency. Shields were tolerated by 56/60 children. Artefacts were absent in 45% of scans. Artefacts on orbits, not affecting and affecting orbit evaluation were noted in 39% and 14% of scans, respectively. Diagnostically insignificant artefacts on intracranial structures were noted in 1 case (2%) with shield misplacement. Mean eye-lens-to-shield distance was 8.8 mm in scans without artefacts, and 4.3 mm and 2.2 mm in scans with unimportant and diagnostically important artefacts, respectively. Artefacts occurred in 8 out of 9 cases with shield wrinkling. Dose reduction remained unchanged for different shield-to-eye distances. Bismuth shielding-related artefacts occurring in paediatric head CT are frequent, superficial and diagnostically insignificant when brain pathology is assessed. Shields should be placed 1 cm above the eyes when orbital pathology is addressed. Shield wrinkling should be avoided. (orig.)

Exploring preferences and non-use values for hidden archaeological artefacts

DEFF Research Database (Denmark)

Lundhede, Thomas; Bille, Trine; Hasler, Berit

2013-01-01

This paper presents a choice experiment study of a proposed wetland restorationproject which aims to preserve archaeological artefacts from Stone Age villages which are presently buried within the topsoil. Wetland restoration can avoid destruction of the artefacts due to agricultural cultivation...

Evaluation method of lead measurement accuracy of gears using a wedge artefact

International Nuclear Information System (INIS)

Komori, Masaharu; Takeoka, Fumi; Kubo, Aizoh; Okamoto, Kazuhiko; Osawa, Sonko; Sato, Osamu; Takatsuji, Toshiyuki

2009-01-01

The reduction of the vibration and noise of gears is an important issue in mechanical devices such as vehicles and wind turbines. The characteristics of the vibration and noise of gears are markedly affected by deviations of the tooth flank form of micrometre order; therefore, a strict quality control of the tooth flank form is required. The accuracy of the lead measurement for a gear-measuring instrument is usually evaluated using a master gear or a lead master. However, it is difficult to manufacture masters with high accuracy because the helix is a complicated geometrical form. In this paper, we propose a method of evaluating a gear-measuring instrument using a wedge artefact, which includes a highly precise plane surface. The concept of the wedge artefact is described and a mathematical model of the measuring condition of the wedge artefact is constructed. Theoretical measurement results for the wedge artefact are calculated. The wedge artefact is designed and produced on the basis of the theoretical measurement results. A measurement experiment using the wedge artefact is carried out and its effectiveness is verified

X-ray CT high-density artefact suppression in cryosurgery

International Nuclear Information System (INIS)

Wei Jikun; Sandison, George A; Chen Laigao; Liang Yun; Xu, Lisa X

2002-01-01

Advantages of x-ray CT for imaging guidance of cryosurgery include 3D visualization of frozen and unfrozen tissue and calibration of temperature in the tissue water-ice interface (0-10 deg. C) to Hounsfield units. However, use of x-ray CT images and their thermal calibration can be compromised by the cryoprobes generating high-density streak artefacts. A new subtraction technique for artefact suppression is proposed and tested in prostate cryosurgery simulations. By subtracting the measured CT x-ray projection profile without cryoprobes from the profile with cryoprobes plus iceballs, one obtains the combined profile of the cryoprobes and a low value background. Polynomial interpolation to obtain the background profile allows its addition to the original profile without probes. The result may then be fed to a conventional filtered back-projection routine to reconstruct the probe-free image. Finally the cryoprobe pixels in the originally constructed image with probes and iceballs are added back to the probe-free image to get the final artefact-suppressed image. The major advantage of this subtraction technique is that it can successfully suppress the high-density artefacts in bone-abundant body regions such as the pelvis. X-ray CT images of cryoprobe arrays in a homogeneous gelatin phantom and the pelvic region of an anthropomorphic Rando phantom containing a human skeleton were generated. After suppression, cryoprobe metal artefact streaks are reduced and visualization of the positions and dimensions of the cryoprobes are well preserved. (note)

Mapping SOA Artefacts onto an Enterprise Reference Architecture Framework

Science.gov (United States)

Noran, Ovidiu

Currently, there is still no common agreement on the service-Oriented architecture (SOA) definition, or the types and meaning of the artefacts involved in the creation and maintenance of an SOA. Furthermore, the SOA image shift from an infrastructure solution to a business-wide change project may have promoted a perception that SOA is a parallel initiative, a competitor and perhaps a successor of enterprise architecture (EA). This chapter attempts to map several typical SOA artefacts onto an enterprise reference framework commonly used in EA. This is done in order to show that the EA framework can express and structure most of the SOA artefacts and therefore, a framework for SOA could in fact be derived from an EA framework with the ensuing SOA-EA integration benefits.

PETRA, MSVAT-SPACE and SEMAC sequences for metal artefact reduction in dental MR imaging

International Nuclear Information System (INIS)

Hilgenfeld, Tim; Heil, Alexander; Bendszus, Martin; Prager, Marcel; Heiland, Sabine; Schwindling, Franz Sebastian; Rammelsberg, Peter; Nittka, Mathias; Grodzki, David

2017-01-01

Dental MRI is often impaired by artefacts due to metallic dental materials. Several sequences were developed to reduce susceptibility artefacts. Here, we evaluated a set of sequences for artefact reduction for dental MRI for the first time. Artefact volume, signal-to-noise ratio (SNR) and image quality were assessed on a 3-T MRI for pointwise encoding time reduction with radial acquisition (PETRA), multiple-slab acquisition with view angle tilting gradient, based on a sampling perfection with application-optimised contrasts using different flip angle evolution (SPACE) sequence (MSVAT-SPACE), slice-encoding for metal-artefact correction (SEMAC) and compared to a standard SPACE and a standard turbo-spin-echo (TSE) sequence. Field-of-view and acquisition times were chosen to enable in vivo application. Two implant-supported prostheses were tested (porcelain fused to metal non-precious alloy and monolithic zirconia). Smallest artefact was measured for TSE sequences with no difference between the standard TSE and the SEMAC. MSVAT-SPACE reduced artefacts about 56% compared to the standard SPACE. Effect of the PETRA was dependent on sample used. Image quality and SNR were comparable for all sequences except PETRA, which yielded poor results. There is no benefit in terms of artefact reduction for SEMAC compared to standard TSE. Usage of MSVAT-SPACE is advantageous since artefacts are reduced and higher resolution is achieved. (orig.)

PETRA, MSVAT-SPACE and SEMAC sequences for metal artefact reduction in dental MR imaging

Energy Technology Data Exchange (ETDEWEB)

Hilgenfeld, Tim; Heil, Alexander; Bendszus, Martin [Heidelberg University Hospital, Department of Neuroradiology, Heidelberg (Germany); Prager, Marcel; Heiland, Sabine [Heidelberg University Hospital, Department of Neuroradiology, Heidelberg (Germany); Heidelberg University Hospital, Section of Experimental Radiology, Heidelberg (Germany); Schwindling, Franz Sebastian; Rammelsberg, Peter [Heidelberg University Hospital, Department of Prosthodontics, Heidelberg (Germany); Nittka, Mathias; Grodzki, David [Siemens Healthcare GmbH, Erlangen (Germany)

2017-12-15

Dental MRI is often impaired by artefacts due to metallic dental materials. Several sequences were developed to reduce susceptibility artefacts. Here, we evaluated a set of sequences for artefact reduction for dental MRI for the first time. Artefact volume, signal-to-noise ratio (SNR) and image quality were assessed on a 3-T MRI for pointwise encoding time reduction with radial acquisition (PETRA), multiple-slab acquisition with view angle tilting gradient, based on a sampling perfection with application-optimised contrasts using different flip angle evolution (SPACE) sequence (MSVAT-SPACE), slice-encoding for metal-artefact correction (SEMAC) and compared to a standard SPACE and a standard turbo-spin-echo (TSE) sequence. Field-of-view and acquisition times were chosen to enable in vivo application. Two implant-supported prostheses were tested (porcelain fused to metal non-precious alloy and monolithic zirconia). Smallest artefact was measured for TSE sequences with no difference between the standard TSE and the SEMAC. MSVAT-SPACE reduced artefacts about 56% compared to the standard SPACE. Effect of the PETRA was dependent on sample used. Image quality and SNR were comparable for all sequences except PETRA, which yielded poor results. There is no benefit in terms of artefact reduction for SEMAC compared to standard TSE. Usage of MSVAT-SPACE is advantageous since artefacts are reduced and higher resolution is achieved. (orig.)

Reduction of metal artefacts in musculoskeletal imaging

International Nuclear Information System (INIS)

Sutter, Reto; Dietrich, Tobias

2016-01-01

Joint replacement and other orthopaedic implants are utilized in many patients with musculoskeletal disorders. While these operations commonly show a good clinical result, a substantial number of patients need to undergo postoperative imaging during follow-up. The presence of orthopaedic implants induces severe metal artefacts at MRI and CT. We review several basic methods and advanced techniques for reducing metal artefacts at MRI and CT in order to enable a diagnostic examination in patients with metal implants. With the use of these techniques, MRI and CT are important and reliable modalities to examine patients with joint replacement and orthopaedic implants.

Technical functions : a drawbridge between the intentional and structural nature of technical artefacts

NARCIS (Netherlands)

Vermaas, P.E.; Houkes, W.N.

2006-01-01

In this paper we present an action-theoretic account of artefact using and designing and describe our ICE-theory of function ascriptions to technical artefacts. By means of this account and theory we analyse the thesis of the dual nature of technical artefacts according to which descriptions of

Some image artefacts in non-contact mode force microscopy

International Nuclear Information System (INIS)

Dinte, B.P.; Watson, G.S.; Dobson, J.F.; Myhra, S.

1996-01-01

Full text: Non-contact mode Atomic Force Microscopy (AFM), performed in air, of two-dimensional hexagonal close-packed (2DHCP) layers of 200 nm diameter polystyrene spheres yields images containing artefacts ('ghost spheres') at layer edges and vacancy sites. The origin of these artefacts is clearly not the simple convolution of the tip and sample geometries, but must be the interaction between them. A computer program was written to simulate the experimental contours, assuming that the only force between the tip and the sample is the van der Waals (dispersion) force, and that the contours traced by the AFM tip are those of constant force derivative. The energy was calculated by integrating R -6 over the volumes of the tip and the sample, with a (constant) arbitrary scaling factor. The experimental contours were reproduced by the simulations, except for the 'ghost' artefacts. The assumption that there is only a dispersion force is thus incorrect. The experiments were performed in air, so that all surfaces were coated by a layer of adsorbed moisture. It is proposed that meniscus forces may be the origin of the artefacts

Manometric evaluation of the esophagus in patients with Behçet's disease.

Science.gov (United States)

Bektas, Mehmet; Altan, Mehmet; Alkan, Murat; Ormeci, Necati; Soykan, Irfan

2007-01-01

Gastrointestinal (GI) involvement in Behçet's disease (BD) mainly appears in mucosa and affects 5-40% of patients, however the effects of the disease on lower esophageal sphincter (LES) pressure and esophageal contractions are not well known. The aims of this study were to evaluate esophageal motor function and to identify whether there was any specific motility pattern for patients with BD who had upper GI symptoms without endoscopic abnormality. 25 patients with BD, with a mean age of 43.1 (range 20-66) years, were admitted to our clinic whose main complaints were dyspeptic such as reflux, epigastric pain, vomiting and bloating. 25 healthy and age-matched individuals were also included in the study as controls. After one night fasting, LES pressure and esophageal contractions were measured. Esophageal motor abnormalities were detected in 16% (4/25) of these patients with manometric studies (non-specific esophageal motor disorder in 1, esophageal hypomotility in 2, and LES hypotension in 1 patient); 16% (4/25) of these patients had endoscopic findings and overall 32% (8/25) of the cases showed esophageal pathology. All cases with esophageal motor abnormalities were suffering from reflux and endoscopy showed grade B esophagitis in 2 of these cases. Median LES pressure and LES relaxation were significantly lower in patients with BD compared to the control group (16.8 +/- 10.5 vs. 20.4 +/- 6.1, p = 0.02, and 92.1 +/- 10.1 vs. 96.4 +/- 4.5, p = 0.03 respectively). Esophageal involvement in BD is significantly high. We propose manometric studies are necessary to evaluate esophageal manifestations in BD patients with esophageal symptoms even without endoscopic findings.

How artefacts influence our actions

NARCIS (Netherlands)

Pols, A.J.K.

2013-01-01

Artefacts can influence our actions in several ways. They can be instruments, enabling and facilitating actions, where their presence affects the number and quality of the options for action available to us. They can also influence our actions in a morally more salient way, where their presence

ARTEFACT MOBILE DATA MODEL TO SUPPORT CULTURAL HERITAGE DATA COLLECTION AND INTERPRETATION

Directory of Open Access Journals (Sweden)

Z. S. Mohamed-Ghouse

2012-07-01

Full Text Available This paper discusses the limitation of existing data structures in mobile mapping applications to support archaeologists to manage the artefact (any object made or modified by a human culture, and later recovered by an archaeological endeavor details excavated at a cultural heritage site. Current limitations of data structure in the mobile mapping application allow archeologist to record only one artefact per test pit location. In reality, more than one artefact can be excavated from the same test pit location. A spatial data model called Artefact Mobile Data Model (AMDM was developed applying existing Relational Data Base Management System (RDBMS technique to overcome the limitation. The data model was implemented in a mobile database environment called SprintDB Pro which was in turn connected to ArcPad 7.1 mobile mapping application through Open Data Base Connectivity (ODBC. In addition, the design of a user friendly application built on top of AMDM to interpret and record the technology associated with each artefact excavated in the field is also discussed in the paper. In summary, the paper discusses the design and implementation of a data model to facilitate the collection of artefacts in the field using integrated mobile mapping and database approach.

An atlas of artefacts: a teaching tool for scintillation camera quality control

International Nuclear Information System (INIS)

Busemann Sokole, E.; Graham, L.S.; Todd-Pokropek, A.; Wegst, A.; Robilotta, C.C.

2002-01-01

Aim: Evaluating results from quality control tests and recognizing possible artefacts in clinical images requires an insight into typical and atypical images and quantitative results. Learning to recognize what is acceptable requires access to different examples, and knowledge of underlying principles of image production. An atlas of image artefacts has been assembled to assist with interpreting quality control tests and recognizing artefacts in clinical images. The project was initiated and supported by the International Atomic Energy Agency (IAEA). Methods: The artefact atlas was developed and written by the first author of this abstract, based on images and information submitted by nuclear medicine users from around the world. Each image artefact example includes an accompanying descriptive text comprising a brief description of the data acquisition, radionuclide/radiopharmaceutical, circumstances under which the image was produced; results describing the images and subsequent conclusions; comments, as appropriate, giving guidelines for trouble shooting and follow-up; and, occasional literature references. The images supplied were mostly hardcopy results on film or paper. All images were digitized into JPEG format for inclusion into a digital document. Most examples were contained on one page. The atlas was reviewed by an international group of experts. Results: A total of about 250 examples from 26 centres in 16 countries were included. The examples are grouped into 6 sections: planar, SPECT, whole body, camera/computer interface, environment/radioactivity, and display/hardcopy. The atlas includes normal results, results from poor adjustment of the camera system, poor results obtained at acceptance testing, artefacts due to system malfunction, and artefacts due to environmental situations. Some image patterns are generic, others specific to system design. Results from different camera systems, as well as new and old generation systems have been included

Computer Simulation of Multidimensional Archaeological Artefacts

Directory of Open Access Journals (Sweden)

Vera Moitinho de Almeida

2013-11-01

Full Text Available The main purpose of this ongoing research is to understand possible function(s of archaeological artefacts through Reverse Engineering processes. In addition, we intend to provide new data, as well as possible explications of the archaeological record according to what it expects about social activities and working processes, by simulating the potentialities of such actions in terms of input-output relationships. Our project focuses on the Neolithic lakeside site of La Draga (Banyoles, Catalonia. In this presentation we will begin by providing a clear overview of the major guidelines used to capture and process 3D digital data of several wooden artefacts. Then, we shall present the use of semi-automated relevant feature extractions. Finally, we intend to share preliminary computer simulation issues.

The manometric sorptomat—an innovative volumetric instrument for sorption measurements performed under isobaric conditions

International Nuclear Information System (INIS)

Kudasik, Mateusz

2016-01-01

The present paper discusses the concept of measuring the process of sorption by means of the volumetric method, developed in such a way as to allow measurements performed under isobaric conditions. On the basis of the concept in question, a prototype of a sorption instrument was built: the manometric sorptomat. The paper provides a detailed description of the idea of the instrument, and of the way it works. In order to evaluate the usefulness of the device in sorption measurements carried out under laboratory conditions, comparative studies were conducted, during which the results of sorption measurements obtained with the developed instrument were compared with the results Mateusz obtained with a reference device. The objects of comparison were the sorption capacities of hard coal samples, calculated on the basis of the established courses of the methane sorption process. The results were regarded as compatible if the compared values fell within the range of the measurement uncertainty of the two devices. For the sake of the comparative studies, fifteen granular samples of hard coal—representing the 0.20–0.25 mm grain fraction and coming from various mines of the Upper Silesian Coal Basin—were used. After comparing the results obtained with the original manometric sorptomat with the results obtained with the gravimetric reference device, it was observed that the compatibility of measurements of sorption capacities was over 90%, based on the defined criterion of the measurement compatibility. (paper)

Intergranular failure of roman silver artefacts

Czech Academy of Sciences Publication Activity Database

Vaníčková, J.; Děd, J.; Bartuška, Pavel; Lejček, Pavel

567-568, - (2007), s. 213-216 ISSN 0255-5476 Institutional research plan: CEZ:AV0Z10100520 Keywords : silver embrittlement * archaeological artefacts * XRD Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.399, year: 2005

Artefact biography 2.0 : the information value of corroded archaeological bronzes

NARCIS (Netherlands)

Nienhuis, J.

2017-01-01

The different phases in the life of archaeological objects can be described by artefact biography. This dissertation defines an updated version: artefact biography 2.0, and the life phases of Early Iron Age bronze studs from Oss-Zevenbergen, the Netherlands, are elaborated. Throughout the thesis,

The radiographic image: A cultural artefact?

International Nuclear Information System (INIS)

Strudwick, Ruth M.

2014-01-01

This article looks at the role of the radiographic images produced by diagnostic radiographers. An ethnographic study of the workplace culture in one diagnostic imaging department was undertaken using participant observation for four months and semi-structured interviews with ten key informants. One of the key themes; that of the radiographic image as a cultural artefact, is explored in this article. The radiographic image is a cultural artefact which radiographers are protective of and take ownership of. Radiographers are conscious of the quality of their images and the images are an important aspect of their work. Radiographers take criticism of their images personally. The radiographic image is a record of the interaction that occurs between the radiographer and the patient. The way in which radiographic images are viewed, used and judged is an important aspect of the role of diagnostic radiographer

Radiographic and manometric correlation in achalasia with apparent lower esophageal sphincter relaxation

International Nuclear Information System (INIS)

Ott, D.J.; Richter, J.E.; Chen, Y.M.; Wu, W.C.; Gelfand, D.W.; Castell, D.O.

1987-01-01

The authors compared the clinical, radiographic, and manometric findings in ten patients with atypical achalasia showing complete but short-duration lower esophageal sphincter (LES) relaxation with findings in 39 patients with classic achalasia. Patients with atypical achalasia were younger, had dysphagia and weight loss of shorter duration, and had less esophageal dilation than patients with classic achalesia. LES pressure and esophagogastric junction caliber, however, were similar in the two groups. The majority of patients in both groups responded well to pneumatic dilation. They conclude that achalasia with apparent LES relaxation may represent an early form of this motor disorder and that the radiographic findings remain characteristic except for less dilation of the esophagus

Modelling of polysomnographic respiratory measurements for artefact detection and signal restoration

International Nuclear Information System (INIS)

Rathnayake, S I; Abeyratne, U R; Hukins, C; Duce, B

2008-01-01

Polysomnography (PSG), which incorporates measures of sleep with measures of EEG arousal, air flow, respiratory movement and oxygenation, is universally regarded as the reference standard in diagnosing sleep-related respiratory diseases such as obstructive sleep apnoea syndrome. Over 15 channels of physiological signals are measured from a subject undergoing a typical overnight PSG session. The signals often suffer from data losses, interferences and artefacts. In a typical sleep scoring session, artefact-corrupted signal segments are visually detected and removed from further consideration. This is a highly time-consuming process, and subjective judgement is required for the job. During typical sleep scoring sessions, the target is the detection of segments of diagnostic interest, and signal restoration is not utilized for distorted segments. In this paper, we propose a novel framework for artefact detection and signal restoration based on the redundancy among respiratory flow signals. We focus on the air flow (thermistor sensors) and nasal pressure signals which are clinically significant in detecting respiratory disturbances. The method treats the respiratory system and other organs that provide respiratory-related inputs/outputs to it (e.g., cardiovascular, brain) as a possibly nonlinear coupled-dynamical system, and uses the celebrated Takens embedding theorem as the theoretical basis for signal prediction. Nonlinear prediction across time (self-prediction) and signals (cross-prediction) provides us with a mechanism to detect artefacts as unexplained deviations. In addition to detection, the proposed method carries the potential to correct certain classes of artefacts and restore the signal. In this study, we categorize commonly occurring artefacts and distortions in air flow and nasal pressure measurements into several groups and explore the efficacy of the proposed technique in detecting/recovering them. The results we obtained from a database of clinical

THE A (H1N1 INFLUENZA. SYMBOLIC DIMENSIONS OF A PANDEMIC ARTEFACT

Directory of Open Access Journals (Sweden)

Andrés G. Seguel

2013-01-01

Full Text Available The aim of the present paper is to present the symbolic features that are exposed by the concept of artefact in the context of a pandemic alarm, such as the A (H1N1 influenza. The symbolic qualities entailed by the notion of artefact are well-known within the Social Sciences: Sociology, Anthropology, Archaeology, and Linguistics. The artefact is basically not an object, but an action aimed at designing, simulating or creating a simile by means of material, technological or linguistic structures. The purpose of the present work is to unveil the symbolic dimensions that are activated by the A (H1N1 influenza as a Pandemic Artefact: a the assumption of separating information from matter; b the need for a material support to enable the exchange; c the sociological reflexivity of the artefact and its agency; d the arbitrariness of its social use, that detaches it from the design as intention.

Novel artefact removal algorithms for co-registered EEG/fMRI based on selective averaging and subtraction.

Science.gov (United States)

de Munck, Jan C; van Houdt, Petra J; Gonçalves, Sónia I; van Wegen, Erwin; Ossenblok, Pauly P W

2013-01-01

Co-registered EEG and functional MRI (EEG/fMRI) is a potential clinical tool for planning invasive EEG in patients with epilepsy. In addition, the analysis of EEG/fMRI data provides a fundamental insight into the precise physiological meaning of both fMRI and EEG data. Routine application of EEG/fMRI for localization of epileptic sources is hampered by large artefacts in the EEG, caused by switching of scanner gradients and heartbeat effects. Residuals of the ballistocardiogram (BCG) artefacts are similarly shaped as epileptic spikes, and may therefore cause false identification of spikes. In this study, new ideas and methods are presented to remove gradient artefacts and to reduce BCG artefacts of different shapes that mutually overlap in time. Gradient artefacts can be removed efficiently by subtracting an average artefact template when the EEG sampling frequency and EEG low-pass filtering are sufficient in relation to MR gradient switching (Gonçalves et al., 2007). When this is not the case, the gradient artefacts repeat themselves at time intervals that depend on the remainder between the fMRI repetition time and the closest multiple of the EEG acquisition time. These repetitions are deterministic, but difficult to predict due to the limited precision by which these timings are known. Therefore, we propose to estimate gradient artefact repetitions using a clustering algorithm, combined with selective averaging. Clustering of the gradient artefacts yields cleaner EEG for data recorded during scanning of a 3T scanner when using a sampling frequency of 2048 Hz. It even gives clean EEG when the EEG is sampled with only 256 Hz. Current BCG artefacts-reduction algorithms based on average template subtraction have the intrinsic limitation that they fail to deal properly with artefacts that overlap in time. To eliminate this constraint, the precise timings of artefact overlaps were modelled and represented in a sparse matrix. Next, the artefacts were disentangled with

Prototype metal artefact reduction algorithm in flat panel computed tomography - evaluation in patients undergoing transarterial hepatic radioembolisation.

Science.gov (United States)

Hamie, Qeumars Mustafa; Kobe, Adrian Raoul; Mietzsch, Leif; Manhart, Michael; Puippe, Gilbert Dominique; Pfammatter, Thomas; Guggenberger, Roman

2018-01-01

To investigate the effect of an on-site prototype metal artefact reduction (MAR) algorithm in cone-beam CT-catheter-arteriography (CBCT-CA) in patients undergoing transarterial radioembolisation (RE) of hepatic masses. Ethical board approved retrospective study of 29 patients (mean 63.7±13.7 years, 11 female), including 16 patients with arterial metallic coils, undergoing CBCT-CA (8s scan, 200 degrees rotation, 397 projections). Image reconstructions with and without prototype MAR algorithm were evaluated quantitatively (streak-artefact attenuation changes) and qualitatively (visibility of hepatic parenchyma and vessels) in near- (3cm) of artefact sources (metallic coils and catheters). Quantitative and qualitative measurements of uncorrected and MAR corrected images and different artefact sources were compared RESULTS: Quantitative evaluation showed significant reduction of near- and far-field streak-artefacts with MAR for both artefact sources (p0.05). Inhomogeneities of attenuation values were significantly higher for metallic coils compared to catheters (pprototype MAR algorithm improves image quality in proximity of metallic coil and catheter artefacts. • Metal objects cause artefacts in cone-beam computed tomography (CBCT) imaging. • These artefacts can be corrected by metal artefact reduction (MAR) algorithms. • Corrected images show significantly better visibility of nearby hepatic vessels and tissue. • Better visibility may facilitate image interpretation, save time and radiation exposure.

Optimization of metal artefact reduction (MAR) sequences for MRI of total hip prostheses

Energy Technology Data Exchange (ETDEWEB)

Toms, A.P., E-mail: andoni.toms@nnuh.nhs.u [Department of Radiology, Norfolk and Norwich University Hospital Trust, Norwich, Norfolk NR4 7UY (United Kingdom); Smith-Bateman, C.; Malcolm, P.N.; Cahir, J. [Department of Radiology, Norfolk and Norwich University Hospital Trust, Norwich, Norfolk NR4 7UY (United Kingdom); Graves, M. [University Department of Radiology, Addenbrooke' s Hospital, Cambridge (United Kingdom)

2010-06-15

Aim: To describe the relative contribution of matrix size and bandwidth to artefact reduction in order to define optimal sequence parameters for metal artefact reduction (MAR) sequences for MRI of total hip prostheses. Methods and materials: A phantom was created using a Charnley total hip replacement. Mid-coronal T1-weighted (echo time 12 ms, repetition time 400 ms) images through the prosthesis were acquired with increasing bandwidths (150, 300, 454, 592, and 781 Hz/pixel) and increasing matrixes of 128, 256, 384, 512, 640, and 768 pixels square. Signal loss from the prosthesis and susceptibility artefact was segmented using an automated tool. Results: Over 90% of the achievable reduction in artefacts was obtained with matrixes of 256 x 256 or greater and a receiver bandwidth of approximately 400 Hz/pixel or greater. Thereafter increasing the receiver bandwidth or matrix had little impact on reducing susceptibility artefacts. Increasing the bandwidth produced a relative fall in the signal-to-noise ratio (SNR) of between 49 and 56% for a given matrix, but, in practice, the image quality was still satisfactory even with the highest bandwidth and largest matrix sizes. The acquisition time increased linearly with increasing matrix parameters. Conclusion: Over 90% of the achievable metal artefact reduction can be realized with mid-range matrices and receiver bandwidths on a clinical 1.5 T system. The loss of SNR from increasing receiver bandwidth, is preferable to long acquisition times, and therefore, should be the main tool for reducing metal artefact.

Artefacts in geometric phase analysis of compound materials

Energy Technology Data Exchange (ETDEWEB)

Peters, Jonathan J.P., E-mail: j.j.p.peters@warwick.ac.uk [Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL (United Kingdom); Beanland, Richard; Alexe, Marin [Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL (United Kingdom); Cockburn, John W.; Revin, Dmitry G.; Zhang, Shiyong Y. [Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield S3 7RH (United Kingdom); Sanchez, Ana M., E-mail: a.m.sanchez@warwick.ac.uk [Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL (United Kingdom)

2015-10-15

The geometric phase analysis (GPA) algorithm is known as a robust and straightforward technique that can be used to measure lattice strains in high resolution transmission electron microscope (TEM) images. It is also attractive for analysis of aberration-corrected scanning TEM (ac-STEM) images that resolve every atom column, since it uses Fourier transforms and does not require real-space peak detection and assignment to appropriate sublattices. Here it is demonstrated that, in ac-STEM images of compound materials with compositionally distinct atom columns, an additional geometric phase is present in the Fourier transform. If the structure changes from one area to another in the image (e.g. across an interface), the change in this additional phase will appear as a strain in conventional GPA, even if there is no lattice strain. Strategies to avoid this pitfall are outlined. - Highlights: • GPA is shown to produce incorrect strains when applied to images of compound materials. • A mathematical description is laid out for why GPA can produce artefacts. • The artefact is demonstrated using experimental and simulated data. • A ‘rule’ is set to avoid this artefact in GPA.

Iterative metal artefact reduction (MAR) in postsurgical chest CT: comparison of three iMAR-algorithms.

Science.gov (United States)

Aissa, Joel; Boos, Johannes; Sawicki, Lino Morris; Heinzler, Niklas; Krzymyk, Karl; Sedlmair, Martin; Kröpil, Patric; Antoch, Gerald; Thomas, Christoph

2017-11-01

The purpose of this study was to evaluate the impact of three novel iterative metal artefact (iMAR) algorithms on image quality and artefact degree in chest CT of patients with a variety of thoracic metallic implants. 27 postsurgical patients with thoracic implants who underwent clinical chest CT between March and May 2015 in clinical routine were retrospectively included. Images were retrospectively reconstructed with standard weighted filtered back projection (WFBP) and with three iMAR algorithms (iMAR-Algo1 = Cardiac algorithm, iMAR-Algo2 = Pacemaker algorithm and iMAR-Algo3 = ThoracicCoils algorithm). The subjective and objective image quality was assessed. Averaged over all artefacts, artefact degree was significantly lower for the iMAR-Algo1 (58.9 ± 48.5 HU), iMAR-Algo2 (52.7 ± 46.8 HU) and the iMAR-Algo3 (51.9 ± 46.1 HU) compared with WFBP (91.6 ± 81.6 HU, p algorithms, respectively. iMAR-Algo2 and iMAR-Algo3 reconstructions decreased mild and moderate artefacts compared with WFBP and iMAR-Algo1 (p algorithms led to a significant reduction of metal artefacts and increase in overall image quality compared with WFBP in chest CT of patients with metallic implants in subjective and objective analysis. The iMARAlgo2 and iMARAlgo3 were best for mild artefacts. IMARAlgo1 was superior for severe artefacts. Advances in knowledge: Iterative MAR led to significant artefact reduction and increase image-quality compared with WFBP in CT after implementation of thoracic devices. Adjusting iMAR-algorithms to patients' metallic implants can help to improve image quality in CT.

Sources of attenuation-correction artefacts in cardiac PET/CT and SPECT/CT.

Science.gov (United States)

McQuaid, Sarah J; Hutton, Brian F

2008-06-01

Respiratory motion during myocardial perfusion imaging can cause artefacts in both positron emission tomography (PET) and single-photon emission computed tomography (SPECT) images when mismatches between emission and transmission datasets arise. In this study, artefacts from different breathing motions were quantified in both modalities to assess key factors in attenuation-correction accuracy. Activity maps were generated using the NURBS-based cardiac-torso phantom for different respiratory cycles, which were projected, attenuation-corrected and reconstructed to form PET and SPECT images. Attenuation-correction was performed with maps at mismatched respiratory phases to observe the effect on the left-ventricular myocardium. Myocardial non-uniformity was assessed in terms of the standard deviation in scores obtained from the 17-segment model and changes in uniformity were compared for each mismatch and modality. Certain types of mismatch led to artefacts and corresponding increases in the myocardial non-uniformity. For each mismatch in PET, the increases in non-uniformity relative to an artefact-free image were as follows: (a) cardiac translation mismatch, 84% +/- 11%; (b) liver mismatch, 59% +/- 10%, (c) lung mismatch from diaphragm contraction, 28% +/- 8%; and (d) lung mismatch from chest-wall motion, 6% +/- 7%. The corresponding factors for SPECT were (a) 61% +/- 8%, (b) 34% +/- 8%, (c) -2% +/- 7)% and (d) -4% +/- 6%. Attenuation-correction artefacts were seen in PET and SPECT images, with PET being more severely affected. The most severe artefacts were produced from mismatches in cardiac and liver position, whereas lung mismatches were less critical. Both cardiac and liver positions must, therefore, be correctly matched during attenuation correction.

Dynamic, diagnostic, and pharmacological radionuclide studies of the esophagus in achalasia: correlation with manometric measurements

Energy Technology Data Exchange (ETDEWEB)

Rozen, P.; Gelfond, M.; Zaltzman, S.; Baron, J.; Gilat, T.

1982-08-01

The esophagus was evaluated in 15 patients with achalasia by continuous gamma camera imaging following ingestion of a semi-solid meal labeled with /sup 99//sup m/Tc. The images were displayed and recorded on a simple computerized data processing/display system. Subsequent cine' mode images of esophagela emptying demonstrated abnormalities of the body of the esophagus not reflected by the manometric examination. Computer-generated time-activity curves representing specific regions of interest were better than manometry in evaluating the results of myotomy, dilatation, and drug therapy. Isosorbide dinitrate significantly improved esophageal emptying.

Augmenting Everyday Artefacts to Support Social Interaction Among Senior Peers

DEFF Research Database (Denmark)

Nazzi, Elena; Sokoler, Tomas

2015-01-01

Novel technological possibilities emerge when tangible and social computing come together. This paper explores the potential of such technology when designing for seniors and their social interaction. Our research is guided by the concept of twitterIDo, which is to make seniors’ everyday activities...... and displays designed to start a dialogue with the seniors on how twitterIDo-technology may fit into their everyday situations. Our findings point out how augmented everyday artefacts can make a positive difference when designing technology in a domain such the one of seniors’ and their social interaction...... more visible by augmenting everyday artefacts to communicate the ongoing activity they are used for. We engaged a local community of seniors in a living lab to explore the possibilities of twitterIDo in real life situations. This paper presents a series of interactive prototypes of everyday artefacts...

Electrically evoked compound action potentials artefact rejection by independent component analysis: procedure automation.

Science.gov (United States)

Akhoun, Idrick; McKay, Colette; El-Deredy, Wael

2015-01-15

Independent-components-analysis (ICA) successfully separated electrically-evoked compound action potentials (ECAPs) from the stimulation artefact and noise (ECAP-ICA, Akhoun et al., 2013). This paper shows how to automate the ECAP-ICA artefact cancellation process. Raw-ECAPs without artefact rejection were consecutively recorded for each stimulation condition from at least 8 intra-cochlear electrodes. Firstly, amplifier-saturated recordings were discarded, and the data from different stimulus conditions (different current-levels) were concatenated temporally. The key aspect of the automation procedure was the sequential deductive source categorisation after ICA was applied with a restriction to 4 sources. The stereotypical aspect of the 4 sources enables their automatic classification as two artefact components, a noise and the sought ECAP based on theoretical and empirical considerations. The automatic procedure was tested using 8 cochlear implant (CI) users and one to four stimulus electrodes. The artefact and noise sources were successively identified and discarded, leaving the ECAP as the remaining source. The automated ECAP-ICA procedure successfully extracted the correct ECAPs compared to standard clinical forward masking paradigm in 22 out of 26 cases. ECAP-ICA does not require extracting the ECAP from a combination of distinct buffers as it is the case with regular methods. It is an alternative that does not have the possible bias of traditional artefact rejections such as alternate-polarity or forward-masking paradigms. The ECAP-ICA procedure bears clinical relevance, for example as the artefact rejection sub-module of automated ECAP-threshold detection techniques, which are common features of CI clinical fitting software. Copyright © 2014. Published by Elsevier B.V.

Fitts' law as a design artefact

DEFF Research Database (Denmark)

Bertelsen, Olav Wedege

1994-01-01

Fitts' law is described and discussed as an example of use of theory in human-computer interaction design. The dichotomy between academic theory and applied theory is rejected and replaced by a radical pragmatic notion of theories as design artefacts. Different roles of theory in design...

Reduction of dental metallic artefacts in CT: Value of a newly developed algorithm for metal artefact reduction (O-MAR)

International Nuclear Information System (INIS)

Kidoh, M.; Nakaura, T.; Nakamura, S.; Tokuyasu, S.; Osakabe, H.; Harada, K.; Yamashita, Y.

2014-01-01

Aim: To evaluate the image quality of O-MAR (Metal Artifact Reduction for Orthopedic Implants) for dental metal artefact reduction. Materials and methods: This prospective study received institutional review board approval and written informed consent was obtained. Thirty patients who had dental implants or dental fillings were included in this study. Computed tomography (CT) images were obtained through the oral cavity and neck during the portal venous phase. The system reconstructed the O-MAR-processed images in addition to the uncorrected images. CT attenuation and image noise of the soft tissue of the oral cavity were compared between the O-MAR and the uncorrected images. Qualitative analysis was undertaken between the two image groups. Results: The image noise of the O-MAR images was significantly lower than that of the uncorrected images (p < 0.01). O-MAR offered plausible attenuations of soft tissue compared with non-O-MAR. Better qualitative scores were obtained in the streaking artefacts and the degree of depiction of the oral cavity with O-MAR compared with non-O-MAR. Conclusion: O-MAR enables the depiction of structures in areas in which this was not previously possible due to dental metallic artefacts in qualitative image analysis. O-MAR images may have a supplementary role in addition to uncorrected images in oral diagnosis

EXPLOITING MIRRORS IN 3D RECONSTRUCTION OF SMALL ARTEFACTS

Directory of Open Access Journals (Sweden)

G. Kontogianni

2018-05-01

Full Text Available 3D reconstruction of small artefacts is very significant in order to capture the details of the whole object irrespective of the documentation method which is used (Ranged Based or Image Based. Sometimes it is very difficult to achieve it because of hidden parts, occlusions, and obstructions which the object has. Hence, more data are necessary in order to 3D digitise the whole of the artefact leading to increased time for collecting and consequently processing the data. A methodology is necessary in order to reduce the collection of the data and therefore their processing time especially in cases of mass digitisation. So in this paper, the use of mirrors in particular high-quality mirrors in the data acquisition phase for the 3D reconstruction of small artefacts is investigated. Two case studies of 3D reconstruction are presented: the first one concerns Range-Based modelling especially a Time of Flight laser scanner is utilised and in the second one Image-Based modelling technique is implemented.

Image recovery by removing stochastic artefacts identified as local asymmetries

International Nuclear Information System (INIS)

Osterloh, K; Zscherpel, U; Ewert, U; Bücherl, T

2012-01-01

Stochastic artefacts are frequently encountered in digital radiography and tomography with neutrons. Most obviously, they are caused by ubiquitous scattered radiation hitting the CCD-sensor. They appear as scattered dots and, at higher frequency of occurrence, they may obscure the image. Some of these dotted interferences vary with time, however, a large portion of them remains persistent so the problem cannot be resolved by collecting stacks of images and to merge them to a median image. The situation becomes even worse in computed tomography (CT) where each artefact causes a circular pattern in the reconstructed plane. Therefore, these stochastic artefacts have to be removed completely and automatically while leaving the original image content untouched. A simplified image acquisition and artefact removal tool was developed at BAM and is available to interested users. Furthermore, an algorithm complying with all the requirements mentioned above was developed that reliably removes artefacts that could even exceed the size of a single pixel without affecting other parts of the image. It consists of an iterative two-step algorithm adjusting pixel values within a 3 × 3 matrix inside of a 5 × 5 kernel and the centre pixel only within a 3 × 3 kernel, resp. It has been applied to thousands of images obtained from the NECTAR facility at the FRM II in Garching, Germany, without any need of a visual control. In essence, the procedure consists of identifying and tackling asymmetric intensity distributions locally with recording each treatment of a pixel. Searching for the local asymmetry with subsequent correction rather than replacing individually identified pixels constitutes the basic idea of the algorithm. The efficiency of the proposed algorithm is demonstrated with a severely spoiled example of neutron radiography and tomography as compared with median filtering, the most convenient alternative approach by visual check, histogram and power spectra analysis.

A short overview of MRI artefacts

African Journals Online (AJOL)

Enrique

sampling in the phase-encoding direction is the significant difference in the time of acquisition in the fre- ... Department of Medical Physics. University of the Free State. Bloemfontein. Fig. 1. Motion artefact (T1 ..... to image expansion for improved definition. IEEE Trans Med Imaging 1994; 3:233-242. 13. Holden M, Breeuwer ...

Removing Ocular Movement Artefacts by a Joint Smoothened Subspace Estimator

Directory of Open Access Journals (Sweden)

Ronald Phlypo

2007-01-01

Full Text Available To cope with the severe masking of background cerebral activity in the electroencephalogram (EEG by ocular movement artefacts, we present a method which combines lower-order, short-term and higher-order, long-term statistics. The joint smoothened subspace estimator (JSSE calculates the joint information in both statistical models, subject to the constraint that the resulting estimated source should be sufficiently smooth in the time domain (i.e., has a large autocorrelation or self predictive power. It is shown that the JSSE is able to estimate a component from simulated data that is superior with respect to methodological artefact suppression to those of FastICA, SOBI, pSVD, or JADE/COM1 algorithms used for blind source separation (BSS. Interference and distortion suppression are of comparable order when compared with the above-mentioned methods. Results on patient data demonstrate that the method is able to suppress blinking and saccade artefacts in a fully automated way.

The Role of Artefacts in Presence Mediation

NARCIS (Netherlands)

Vyas, Dhaval; Tzovaras, D

2007-01-01

Approaches to support computer mediated communication (CMC) have predominantly relied on the face-to-face communication paradigm. However, interaction and coordination can also be supported by different technological artefacts. In fact, most researches [1, 2, 3] related to ethnomethodology have

Ring down artefacts on abdominal sonography to predict pulmonary abnormalities in the emergency department.

Science.gov (United States)

Tsai, C-L; Wang, H-P; Lien, W-C; Chen, C-C; Lai, T-I; Chen, W-J

2005-10-01

Ring down artefacts are sometimes found when emergency physicians perform abdominal ultrasound to differentiate between various abdominal problems. We describe a patient who presented with right upper quadrant abdominal pain and whose ultrasound examination showed ring down artefacts posterior to the right hemidiaphragm, which led to the eventual diagnosis of pneumonia. Ring down artefacts on ultrasound may be used to predict pulmonary abnormalities. Awareness of this sonographic finding may assist in accurate diagnosis and administration of appropriate treatment without delay.

Head and neck imaging with PET and PET/CT: artefacts from dental metallic implants

International Nuclear Information System (INIS)

Goerres, Gerhard W.; Hany, Thomas F.; Kamel, Ehab; Schulthess von, Gustav K.; Buck, Alfred

2002-01-01

Germanium-68 based attenuation correction (PET Ge68 ) is performed in positron emission tomography (PET) imaging for quantitative measurements. With the recent introduction of combined in-line PET/CT scanners, CT data can be used for attenuation correction. Since dental implants can cause artefacts in CT images, CT-based attenuation correction (PET CT ) may induce artefacts in PET images. The purpose of this study was to evaluate the influence of dental metallic artwork on the quality of PET images by comparing non-corrected images and images attenuation corrected by PET Ge68 and PET CT . Imaging was performed on a novel in-line PET/CT system using a 40-mAs scan for PET CT in 41 consecutive patients with high suspicion of malignant or inflammatory disease. In 17 patients, additional PET Ge68 images were acquired in the same imaging session. Visual analysis of fluorine-18 fluorodeoxyglucose (FDG) distribution in several regions of the head and neck was scored on a 4-point scale in comparison with normal grey matter of the brain in the corresponding PET images. In addition, artefacts adjacent to dental metallic artwork were evaluated. A significant difference in image quality scoring was found only for the lips and the tip of the nose, which appeared darker on non-corrected than on corrected PET images. In 33 patients, artefacts were seen on CT, and in 28 of these patients, artefacts were also seen on PET imaging. In eight patients without implants, artefacts were seen neither on CT nor on PET images. Direct comparison of PET Ge68 and PET CT images showed a different appearance of artefacts in 3 of 17 patients. Malignant lesions were equally well visible using both transmission correction methods. Dental implants, non-removable bridgework etc. can cause artefacts in attenuation-corrected images using either a conventional 68 Ge transmission source or the CT scan obtained with a combined PET/CT camera. We recommend that the non-attenuation-corrected PET images also be

Dosimetric impact of a CT metal artefact suppression algorithm for proton, electron and photon therapies

International Nuclear Information System (INIS)

Wei Jikun; Sandison, George A; Hsi, W-C; Ringor, Michael; Lu Xiaoyi

2006-01-01

Accurate dose calculation is essential to precision radiation treatment planning and this accuracy depends upon anatomic and tissue electron density information. Modern treatment planning inhomogeneity corrections use x-ray CT images and calibrated scales of tissue CT number to electron density to provide this information. The presence of metal in the volume scanned by an x-ray CT scanner causes metal induced image artefacts that influence CT numbers and thereby introduce errors in the radiation dose distribution calculated. This paper investigates the dosimetric improvement achieved by a previously proposed x-ray CT metal artefact suppression technique when the suppressed images of a patient with bilateral hip prostheses are used in commercial treatment planning systems for proton, electron or photon therapies. For all these beam types, this clinical image and treatment planning study reveals that the target may be severely underdosed if a metal artefact-contaminated image is used for dose calculations instead of the artefact suppressed one. Of the three beam types studied, the metal artefact suppression is most important for proton therapy dose calculations, intermediate for electron therapy and least important for x-ray therapy but still significant. The study of a water phantom having a metal rod simulating a hip prosthesis indicates that CT numbers generated after image processing for metal artefact suppression are accurate and thus dose calculations based on the metal artefact suppressed images will be of high fidelity

A framework to evaluate the educational potential of a digital artefact for math learning

Directory of Open Access Journals (Sweden)

Chiappini Giampaolo

2015-12-01

Full Text Available This article provides a methodology with two potential applications: to prove useful to maths teachers for analysing and evaluating the educational potential of different digital artefacts and to help designers of maths learning artefacts to evaluate their design during the implementation phase. The educational potential of an artefact is considered as an entity determined by actions and representations structure available within the artefact, the interpretation and behaviour of who uses it and the features of the activity in which it is used. The proposed methodology is based on the notions of affordance, narrative and cycle of expansive learning. The methodology has been applied on AlNuSet, a system designed for supporting the teaching and learning of algebra by means of modalities of interaction that are of visual, spatial and motor nature.

ASPECTS OF BIODETERIORATION OF LAPIDEOUS SUBMERGED ARTEFACTS: 3D METHODOLOGIES APPLICATION

Directory of Open Access Journals (Sweden)

S. Ricci

2015-04-01

Full Text Available Submerged stone archaeological artefacts are bioeroded by endolithic microbiota (cyanobacteria, algae and fungi and macroborers (Porifera, Bivalvia and Sipuncula. Optical microscope and SEM observations permit to analyse the bioerosion traces and to identify bioeroders. Data obtained with these techniques cannot be used to estimate volumes of material bioeroded. This aspect require the need to collect three-dimensional, close-range data from artefact. In this work we illustrate two 3D imaging techniques used to study bioerosion phenomena of underwater Cultural Heritage. In particular Digital Video Microscope permit the elaboration of 3D images, which are widely employed for close-range acquisitions. Underwater Laser Scanner documents the in situ degradation of submerged artefacts. This research aims to sensitize specialist figures in the study 3D offering a starting point for future collaborations that could lead to interesting results.

Prototype metal artefact reduction algorithm in flat panel computed tomography - evaluation in patients undergoing transarterial hepatic radioembolisation

International Nuclear Information System (INIS)

Hamie, Qeumars Mustafa; Kobe, Adrian Raoul; Mietzsch, Leif; Puippe, Gilbert Dominique; Pfammatter, Thomas; Guggenberger, Roman; Manhart, Michael

2018-01-01

To investigate the effect of an on-site prototype metal artefact reduction (MAR) algorithm in cone-beam CT-catheter-arteriography (CBCT-CA) in patients undergoing transarterial radioembolisation (RE) of hepatic masses. Ethical board approved retrospective study of 29 patients (mean 63.7±13.7 years, 11 female), including 16 patients with arterial metallic coils, undergoing CBCT-CA (8s scan, 200 degrees rotation, 397 projections). Image reconstructions with and without prototype MAR algorithm were evaluated quantitatively (streak-artefact attenuation changes) and qualitatively (visibility of hepatic parenchyma and vessels) in near- (<1cm) and far-field (>3cm) of artefact sources (metallic coils and catheters). Quantitative and qualitative measurements of uncorrected and MAR corrected images and different artefact sources were compared Quantitative evaluation showed significant reduction of near- and far-field streak-artefacts with MAR for both artefact sources (p<0.001), while remaining stable for unaffected organs (all p>0.05). Inhomogeneities of attenuation values were significantly higher for metallic coils compared to catheters (p<0.001) and decreased significantly for both after MAR (p<0.001). Qualitative image scores were significantly improved after MAR (all p<0.003) with by trend higher artefact degrees for metallic coils compared to catheters. In patients undergoing CBCT-CA for transarterial RE, prototype MAR algorithm improves image quality in proximity of metallic coil and catheter artefacts. (orig.)

Prototype metal artefact reduction algorithm in flat panel computed tomography - evaluation in patients undergoing transarterial hepatic radioembolisation

Energy Technology Data Exchange (ETDEWEB)

Hamie, Qeumars Mustafa; Kobe, Adrian Raoul; Mietzsch, Leif; Puippe, Gilbert Dominique; Pfammatter, Thomas; Guggenberger, Roman [University Hospital Zurich, Department of Radiology, Zurich (Switzerland); Manhart, Michael [Imaging Concepts, HC AT IN IMC, Siemens Healthcare GmbH, Advanced Therapies, Innovation, Forchheim (Germany)

2018-01-15

To investigate the effect of an on-site prototype metal artefact reduction (MAR) algorithm in cone-beam CT-catheter-arteriography (CBCT-CA) in patients undergoing transarterial radioembolisation (RE) of hepatic masses. Ethical board approved retrospective study of 29 patients (mean 63.7±13.7 years, 11 female), including 16 patients with arterial metallic coils, undergoing CBCT-CA (8s scan, 200 degrees rotation, 397 projections). Image reconstructions with and without prototype MAR algorithm were evaluated quantitatively (streak-artefact attenuation changes) and qualitatively (visibility of hepatic parenchyma and vessels) in near- (<1cm) and far-field (>3cm) of artefact sources (metallic coils and catheters). Quantitative and qualitative measurements of uncorrected and MAR corrected images and different artefact sources were compared Quantitative evaluation showed significant reduction of near- and far-field streak-artefacts with MAR for both artefact sources (p<0.001), while remaining stable for unaffected organs (all p>0.05). Inhomogeneities of attenuation values were significantly higher for metallic coils compared to catheters (p<0.001) and decreased significantly for both after MAR (p<0.001). Qualitative image scores were significantly improved after MAR (all p<0.003) with by trend higher artefact degrees for metallic coils compared to catheters. In patients undergoing CBCT-CA for transarterial RE, prototype MAR algorithm improves image quality in proximity of metallic coil and catheter artefacts. (orig.)

A knowledge-based method for reducing attenuation artefacts caused by cardiac appliances in myocardial PET/CT

International Nuclear Information System (INIS)

Hamill, James J; Brunken, Richard C; Bybel, Bohdan; DiFilippo, Frank P; Faul, David D

2006-01-01

Attenuation artefacts due to implanted cardiac defibrillator leads have previously been shown to adversely impact cardiac PET/CT imaging. In this study, the severity of the problem is characterized, and an image-based method is described which reduces the resulting artefact in PET. Automatic implantable cardioverter defibrillator (AICD) leads cause a moving-metal artefact in the CT sections from which the PET attenuation correction factors (ACFs) are derived. Fluoroscopic cine images were measured to demonstrate that the defibrillator's highly attenuating distal shocking coil moves rhythmically across distances on the order of 1 cm. Rhythmic motion of this magnitude was created in a phantom with a moving defibrillator lead. A CT study of the phantom showed that the artefact contained regions of incorrect, very high CT values and adjacent regions of incorrect, very low CT values. The study also showed that motion made the artefact more severe. A knowledge-based metal artefact reduction method (MAR) is described that reduces the magnitude of the error in the CT images, without use of the corrupted sinograms. The method modifies the corrupted image through a sequence of artefact detection procedures, morphological operations, adjustments of CT values and three-dimensional filtering. The method treats bone the same as metal. The artefact reduction method is shown to run in a few seconds, and is validated by applying it to a series of phantom studies in which reconstructed PET tracer distribution values are wrong by as much as 60% in regions near the CT artefact when MAR is not applied, but the errors are reduced to about 10% of expected values when MAR is applied. MAR changes PET image values by a few per cent in regions not close to the artefact. The changes can be larger in the vicinity of bone. In patient studies, the PET reconstruction without MAR sometimes results in anomalously high values in the infero-septal wall. Clinical performance of MAR is assessed by two

METHODOLOGY TO CREATE DIGITAL AND VIRTUAL 3D ARTEFACTS IN ARCHAEOLOGY

Directory of Open Access Journals (Sweden)

Calin Neamtu

2016-12-01

Full Text Available The paper presents a methodology to create 3D digital and virtual artefacts in the field of archaeology using CAD software solution. The methodology includes the following steps: the digitalization process, the digital restoration and the dissemination process within a virtual environment. The resulted 3D digital artefacts have to be created in files formats that are compatible with a large variety of operating systems and hardware configurations such as: computers, graphic tablets and smartphones. The compatibility and portability of these 3D file formats has led to a series of quality related compromises to the 3D models in order to integrate them on in a wide variety of application that are running on different hardware configurations. The paper illustrates multiple virtual reality and augmented reality application that make use of the virtual 3D artefacts that have been generated using this methodology.

Statistical iterative reconstruction for streak artefact reduction when using multidetector CT to image the dento-alveolar structures.

Science.gov (United States)

Dong, J; Hayakawa, Y; Kober, C

2014-01-01

When metallic prosthetic appliances and dental fillings exist in the oral cavity, the appearance of metal-induced streak artefacts is not avoidable in CT images. The aim of this study was to develop a method for artefact reduction using the statistical reconstruction on multidetector row CT images. Adjacent CT images often depict similar anatomical structures. Therefore, reconstructed images with weak artefacts were attempted using projection data of an artefact-free image in a neighbouring thin slice. Images with moderate and strong artefacts were continuously processed in sequence by successive iterative restoration where the projection data was generated from the adjacent reconstructed slice. First, the basic maximum likelihood-expectation maximization algorithm was applied. Next, the ordered subset-expectation maximization algorithm was examined. Alternatively, a small region of interest setting was designated. Finally, the general purpose graphic processing unit machine was applied in both situations. The algorithms reduced the metal-induced streak artefacts on multidetector row CT images when the sequential processing method was applied. The ordered subset-expectation maximization and small region of interest reduced the processing duration without apparent detriments. A general-purpose graphic processing unit realized the high performance. A statistical reconstruction method was applied for the streak artefact reduction. The alternative algorithms applied were effective. Both software and hardware tools, such as ordered subset-expectation maximization, small region of interest and general-purpose graphic processing unit achieved fast artefact correction.

Minimizing EIT image artefacts from mesh variability in finite element models.

Science.gov (United States)

Adler, Andy; Lionheart, William R B

2011-07-01

Electrical impedance tomography (EIT) solves an inverse problem to estimate the conductivity distribution within a body from electrical simulation and measurements at the body surface, where the inverse problem is based on a solution of Laplace's equation in the body. Most commonly, a finite element model (FEM) is used, largely because of its ability to describe irregular body shapes. In this paper, we show that simulated variations in the positions of internal nodes within a FEM can result in serious image artefacts in the reconstructed images. Such variations occur when designing FEM meshes to conform to conductivity targets, but the effects may also be seen in other applications of absolute and difference EIT. We explore the hypothesis that these artefacts result from changes in the projection of the anisotropic conductivity tensor onto the FEM system matrix, which introduces anisotropic components into the simulated voltages, which cannot be reconstructed onto an isotropic image, and appear as artefacts. The magnitude of the anisotropic effect is analysed for a small regular FEM, and shown to be proportional to the relative node movement as a fraction of element size. In order to address this problem, we show that it is possible to incorporate a FEM node movement component into the formulation of the inverse problem. These results suggest that it is important to consider artefacts due to FEM mesh geometry in EIT image reconstruction.

Assessing ECG signal quality indices to discriminate ECGs with artefacts from pathologically different arrhythmic ECGs.

Science.gov (United States)

Daluwatte, C; Johannesen, L; Galeotti, L; Vicente, J; Strauss, D G; Scully, C G

2016-08-01

False and non-actionable alarms in critical care can be reduced by developing algorithms which assess the trueness of an arrhythmia alarm from a bedside monitor. Computational approaches that automatically identify artefacts in ECG signals are an important branch of physiological signal processing which tries to address this issue. Signal quality indices (SQIs) derived considering differences between artefacts which occur in ECG signals and normal QRS morphology have the potential to discriminate pathologically different arrhythmic ECG segments as artefacts. Using ECG signals from the PhysioNet/Computing in Cardiology Challenge 2015 training set, we studied previously reported ECG SQIs in the scientific literature to differentiate ECG segments with artefacts from arrhythmic ECG segments. We found that the ability of SQIs to discriminate between ECG artefacts and arrhythmic ECG varies based on arrhythmia type since the pathology of each arrhythmic ECG waveform is different. Therefore, to reduce the risk of SQIs classifying arrhythmic events as noise it is important to validate and test SQIs with databases that include arrhythmias. Arrhythmia specific SQIs may also minimize the risk of misclassifying arrhythmic events as noise.

Comparison of methods for suppressing edge and aliasing artefacts in iterative x-ray CT reconstruction

International Nuclear Information System (INIS)

Zbijewski, Wojciech; Beekman, Freek J

2006-01-01

X-ray CT images obtained with iterative reconstruction (IR) can be hampered by the so-called edge and aliasing artefacts, which appear as interference patterns and severe overshoots in the areas of sharp intensity transitions. Previously, we have demonstrated that these artefacts are caused by discretization errors during the projection simulation step in IR. Although these errors are inherent to IR, they can be adequately suppressed by reconstruction on an image grid that is finer than that typically used for analytical methods such as filtered back-projection. Two other methods that may prevent edge artefacts are: (i) smoothing the projections prior to reconstruction or (ii) using an image representation different from voxels; spherically symmetric Kaiser-Bessel functions are a frequently employed example of such a representation. In this paper, we compare reconstruction on a fine grid with the two above-mentioned alternative strategies for edge artefact reduction. We show that the use of a fine grid results in a more adequate suppression of artefacts than the smoothing of projections or using the Kaiser-Bessel image representation

A Philosophical Framework for Enhancing the Understanding of Artefacts in the Technology Classroom

Science.gov (United States)

Rauscher, Willem

2016-01-01

Technology teachers should have a sound understanding and knowledge of artefacts in order to assist learners in the designing, making and evaluating of artefacts. Unfortunately, technology teachers in South African schools seem to have a poor grasp of the complexity of this important part of knowledge that is specific to technology. As a result,…

A knowledge-based method for reducing attenuation artefacts caused by cardiac appliances in myocardial PET/CT

Energy Technology Data Exchange (ETDEWEB)

Hamill, James J [Siemens Medical Solutions, Molecular Imaging, 810 Innovation Dr., Knoxville, TN (United States); Brunken, Richard C [Department of Molecular and Functional Imaging, Cleveland Clinic Foundation, 9500 Euclid Ave., Cleveland, OH (United States); Bybel, Bohdan [Department of Molecular and Functional Imaging, Cleveland Clinic Foundation, 9500 Euclid Ave., Cleveland, OH (United States); DiFilippo, Frank P [Department of Molecular and Functional Imaging, Cleveland Clinic Foundation, 9500 Euclid Ave., Cleveland, OH (United States); Faul, David D [Siemens Medical Solutions, Molecular Imaging, 810 Innovation Dr., Knoxville, TN (United States)

2006-06-07

Attenuation artefacts due to implanted cardiac defibrillator leads have previously been shown to adversely impact cardiac PET/CT imaging. In this study, the severity of the problem is characterized, and an image-based method is described which reduces the resulting artefact in PET. Automatic implantable cardioverter defibrillator (AICD) leads cause a moving-metal artefact in the CT sections from which the PET attenuation correction factors (ACFs) are derived. Fluoroscopic cine images were measured to demonstrate that the defibrillator's highly attenuating distal shocking coil moves rhythmically across distances on the order of 1 cm. Rhythmic motion of this magnitude was created in a phantom with a moving defibrillator lead. A CT study of the phantom showed that the artefact contained regions of incorrect, very high CT values and adjacent regions of incorrect, very low CT values. The study also showed that motion made the artefact more severe. A knowledge-based metal artefact reduction method (MAR) is described that reduces the magnitude of the error in the CT images, without use of the corrupted sinograms. The method modifies the corrupted image through a sequence of artefact detection procedures, morphological operations, adjustments of CT values and three-dimensional filtering. The method treats bone the same as metal. The artefact reduction method is shown to run in a few seconds, and is validated by applying it to a series of phantom studies in which reconstructed PET tracer distribution values are wrong by as much as 60% in regions near the CT artefact when MAR is not applied, but the errors are reduced to about 10% of expected values when MAR is applied. MAR changes PET image values by a few per cent in regions not close to the artefact. The changes can be larger in the vicinity of bone. In patient studies, the PET reconstruction without MAR sometimes results in anomalously high values in the infero-septal wall. Clinical performance of MAR is assessed by

Matter(s) of interest: artefacts, spacing and timing

NARCIS (Netherlands)

Schwanen, T.

2007-01-01

This paper argues that time-geography can make a contribution to contemporary 'rematerialized' geographies, because the interconnections among social processes, human corporeality and inanimate material artefacts within the landscape were among Hägerstrand's central concerns. Time-geography needs

Designing the e-Participation Artefact

DEFF Research Database (Denmark)

Sanford, Clive Carlton; Rose, Jeremy

2008-01-01

When e-participation is considered in the context of applied research, researchers support government institutions by enabling technology for citizens who participate in policy-making. Governments' e-participation agendas involve a variety of different design activities; for example, designing new...... administrative procedures, computer literacy programs, or creating new laws. Design science aids the creation and evaluation of artefacts that are intended to find solutions to identified problems in a rigorous way. We therefore characterise three different types of e-participation design activities...

Computer Simulation of Multidimensional Archaeological Artefacts

Directory of Open Access Journals (Sweden)

Vera Moitinho de Almeida

2012-11-01

Our project focuses on the Neolithic lakeside site of La Draga (Banyoles, Catalonia. In this presentation we will begin by providing a clear overview of the major guidelines used to capture and process 3D digital data of several wooden artefacts. Then, we shall present the use of semi-automated relevant feature extractions. Finally, we intend to share preliminary computer simulation issues.

Endosonographic and manometric evaluation of internal anal sphincter in patients with chronic anal fissure and its correlation with clinical outcome after topical glyceryl trinitrate therapy.

Science.gov (United States)

Pascual, Marta; Pera, Miguel; Courtier, Ricard; Gil, Mariá José; Parés, David; Puig, Sonia; Andreu, Montserrat; Grande, Luis

2007-08-01

Anorectal pressure studies have demonstrated internal anal sphincter (IAS) hypertonia in patients with chronic anal fissure. It is unknown however, if these changes in IAS function are associated with any abnormality in sphincter morphology. The first aim was to investigate the clinical characteristics and the manometric and endosonographic findings of the IAS in a cohort of patients with chronic anal fissure. The second aim was to investigate the association between these findings and the outcome with topical Glyceryl trinitrate (GTN) therapy. All patients who presented with chronic anal fissure from November 1999 to May 2004 were included after failure of conservative therapy. Anorectal manometry and anal endosonography were performed before treatment with 0.2% GTN ointment twice daily was initiated. Patients were evaluated after 8 weeks. One hundred and twenty-four patients (66 women, mean age, 45.2 +/- 14.8 years) were included. Hypertonia of the IAS was found in 84 (68%) patients. The mean maximum IAS thickness was 3.6 +/- 0.76 mm (1.6-5.5). An abnormally thick IAS, adjusted by age, was observed in 113 (91.1%) patients. We found no correlation between resting pressure and IAS thickness (r = 0.074; p = 0.41). At 8 weeks, 52 patients (42%) had healed with complete symptoms resolution. No statistically significant differences were observed when clinical features and manometric and endosonographic findings were compared between healing and no-healing fissures. The majority of patients with chronic anal fissure present an abnormally thick IAS. Clinical, manometric and endosonographic features had no association with outcome after GTN treatment.

Preliminary Results of Ocular Artefacts Identification in EEC Series by Neural Network

Directory of Open Access Journals (Sweden)

M. Kofronova

1996-06-01

Full Text Available The human electroencephalogram (EEG, is record of the electrical activity of the brain and contains useful diagnostic information on a variety of neurological disorders. Normal EEG signal are usually registered from electrodes placed on the scalp, and are often very small in amplitude, of 20 µV. The EEG, like all biomedical signals, is very susceptible to a variety of large signal contamination or artefacts (signals of other than brain activity which reduce its clinical usefulness. For example, blinking or moving eyes produces large electrical potentials around the eyes called the electrooculogram (EOG. The EOG spreads across the scalp to contaminate the EEG, when it is referred to as an ocular artefact (OA. This paper includes method of identification portion of the EEG record where ocular artefact appears and classification its type by neural network.

ECG movement artefacts can be greatly reduced with the aid of a movement absorbing device

DEFF Research Database (Denmark)

Harrison, Adrian Paul; Wandall, Kirsten; Thorball, Jørgen

2007-01-01

Accurate ECG signal analysis can be confounded by electric lead, and/or electrode movements varying in origin from, for example, hiccups, tremor or patient restlessness. ECG signals recorded using either a conventional electrode holder or with the aid of an electrode holder capable of absorbing...... movement artefacts, were measured on a healthy human subject. Results show a greatly improved stability of the ECG signal recorded using an electrode holder capable of absorbing movement artefacts during periods of lead disturbance, and highlight the movement artefacts that develop when the recording lead...... of a conventional ECG electrode holder is tugged or pulled during theperiod of monitoring. It is concluded that the new design of ECG electrode holder will not only enable clearer signal recordings for clinical assessment, but will reduce the ECG artefacts associated with the transportation of patients, and may...

Problem Solving of Low Data Throughput on Mobile Devices by Artefacts Prebuffering

Directory of Open Access Journals (Sweden)

Krejcar Ondrej

2009-01-01

Full Text Available The paper deals with a problem of low data throughput on wirelessly connected mobile devices and a possibility to solve this problem by prebuffering of selected artefacts. The basics are in determining the problem parts of a mobile device and solve the problem by a model of data prebuffering-based system enhancement for locating and tracking users inside the buildings. The framework uses a WiFi network infrastructure to allow the mobile device determine its indoor position. User location is used for data prebuffering and for pushing information from a server to PDAs. All server data are saved as artefacts with its indoor position information. Accessing prebuffered data on a mobile device can significantly improve a response time needed to view large multimedia data. The solution was tested on a facility management information system built on purpose with a testing collection of about hundred large size artefacts.

Superiority of triple-detector single-photon emission tomography over single- and dual-detector systems in the minimization of motion artefacts

International Nuclear Information System (INIS)

Nakajima, Kenichi; Taki, Junichi; Michigishi, Takatoshi; Tonami, Norihisa

1998-01-01

A patient motion-related artefact is one of the most important artefacts in single-photon emission tomography (SPET) imaging. This study evaluated the effect of the number and configuration of SPET detectors on motion artefacts. The following acquisition conditions were simulated based on original 360 projection images: (1) single-detector 180 rotation (S180), (2) a dual-detector rectangular (L-shaped) 180 acquisition (D180L), (3) dual-detector cameras mounted opposite each other with 360 acquisition (D360) and (4) triple-detector 360 acquisition (T360). The motion artefacts were introduced using a syringe and a myocardial phantom. Clinical cases with technetium-99m methoxyisobutylisonitrile and thallium-201 studies were analysed to confirm the validity of this phantom simulation. The effect of continuous alternate rotation acquisition and summing the projections on the reduction of motion artefacts was investigated in each model. The effect of motion depended on the number and the configuration of the SPET detectors. A 1-pixel (6.4 mm) motion in the S180, D180L and D360 models generated only slight artefacts, and a 2-pixel motion led to an apparent decrease in activity or created hot areas in the myocardium. On the other hand, a T360 rotation created few artefacts even with a 2-pixel motion of the last quarter of the projections. Despite the difference in attenuation with 201 Tl and 99m Tc, similar artefact patterns were observed with both radionuclides in selected patient model studies. Continuous alternate rotation could reduce artefacts caused by less than a 2-pixel motion. In conclusion, calculating the average of the sum of the projections of triple-detector 360 rotations with alternate rotation is the best method to minimize motion artefacts. This ''averaging'' effect of motion artefacts is a key to this simulation. (orig.)

MRI with intraoral orthodontic appliance-a comparative in vitro and in vivo study of image artefacts at 1.5 T.

Science.gov (United States)

Zachriat, C; Asbach, P; Blankenstein, K I; Peroz, I; Blankenstein, F H

2015-01-01

We investigated artefacts caused from orthodontic appliances at 1.5-T MRI of the head and neck region and whether the image quality can be improved utilizing the artefact-minimizing sequence WARP. In vitro tests were performed by phantom measurements of different orthodontic devices applying different types of MR sequences [echoplanar imaging (EPI), turbo spin echo (TSE) and TSE-WARP, gradient echo (GRE)]. Two independent readers determined after calibration the level of artefacts. Subsequently, the interobserver agreement was calculated. The measurement of artefacts was based on the American Society for Testing Materials Standard F 2119-07. For in vivo imaging, one test person was scanned with an inserted multibracket appliance. The level of artefacts for 27 target regions was evaluated. In vitro: ceramic brackets and ferromagnetic steel brackets produced artefact radii up to 1.12 and 7.40 cm, respectively. WARP reduced these artefacts by an average of 32.7%. The Bland-Altman-Plot indicated that maximum measurement differences of 3 mm have to be expected with two calibrated observers. In vivo: the EPI sequence for brain imaging was not analysable. The TSE sequence of the brain did not demonstrate artefacts except for the nasal cavity. Conversely, the TSE sequence of the cervical spine revealed severe artefacts in the midface region. The GRE sequence appeared to be more susceptible to artefacts than did the TSE sequence. In vitro measurements allow an estimation of the in vivo artefact size. Orthodontic appliances may often remain intraorally when performing MRI. WARP showed a more significant effect in vitro than in vivo.

Understanding sudden environmental and societal change through coupled geochronological and artefact shape analyses

DEFF Research Database (Denmark)

Hoggard, Christian Steven; Sauer, Florian Rudolf; Zernack, Anke Verena

Over the last twenty years, advances in geometric morphometric methodologies have revolutionised how archaeologists understand changes in artefact shape and form (size plus shape) throughout the Quaternary period. Such methodologies provide a high resolution of artefact coverage, and allow...... a critical analysis of previous taxonomic classificatory schemas and human tool-use in the past. Despite this, methodologies into artefact shape through geometric morphometrics have not been integrated within extensive geochronological data to better understand periods of high environmental stress and......, with respect to archaeology, how past societies reacted to such stress. The Laacher See volcanic eruption (c. 13,000 BP) in western Germany is believed, given its hypothesised characteristics, to have had profound impact on the lifeways of hunter-gatherers towards the end of the Final Palaeolithic (Riede, 2017...

Non-invasive NMR stratigraphy of a multi-layered artefact: an ancient detached mural painting.

Science.gov (United States)

Di Tullio, Valeria; Capitani, Donatella; Presciutti, Federica; Gentile, Gennaro; Brunetti, Brunetto Giovanni; Proietti, Noemi

2013-10-01

NMR stratigraphy was used to investigate in situ, non-destructively and non-invasively, the stratigraphy of hydrogen-rich layers of an ancient Nubian detached mural painting. Because of the detachment procedure, a complex multi-layered artefact was obtained, where, besides layers of the original mural painting, also the materials used during the procedure all became constitutive parts of the artefact. NMR measurements in situ enabled monitoring of the state of conservation of the artefact and planning of minimum representative sampling to validate results obtained in situ by solid-state NMR analysis of the samples. This analysis enabled chemical characterization of all organic materials. Use of reference compounds and prepared specimens assisted data interpretation.

Stratigraphy, artefact industries and hominid associations for Sterkfontein, member 5.

Science.gov (United States)

Kuman, K; Clarke, R J

2000-06-01

A revised stratigraphy for the early hominid site of Sterkfontein (Gauteng Province, South Africa) reveals a complex distribution of infills in the main excavation area between 2.8 and 1.4 m.y.a, as well as deposits dating to the mid to late Pleistocene. New research now shows that the Member 4 australopithecine breccia (2.8-2.6 Ma) extends further west than was previously thought, while a late phase of Member 4 is recognized in a southern area. The artefact-bearing breccias were defined sedimentologically as Member 5, but one supposed part of these younger breccias, the StW 53 infill, lacks in situ stone tools, although it does appear to post-date 2.6 Ma when artefacts first appear in the archaeological record. The StW 53 hominid, previously referred to Homo habilis, is here argued to be Australopithecus. The first artefact-bearing breccia of Member 5 is the Oldowan Infill, estimated at 2-1.7 Ma. It occupies a restricted distribution in Member 5 east and contains an expedient, flake-based tool industry associated with a few fossils of Paranthropos robustus. An enlarged cave opening subsequently admitted one or more Early Acheulean infills associated in Member 5 west with Homo ergaster. The artefacts attest to a larger site accumulation between ca. 1.7 and 1.4 Ma, with more intensive use of quartzite over quartz and a subtle but important shift to large flakes and heavier-duty tools. The available information on palaeoenvironments is summarized, showing an overall change from tropical to sub-tropical gallery forest, forest fringe and woodland conditions in Member 4 to more open woodland and grassland habitats in the later units, but with suggestions of a wet localized topography in the Paranthropus -bearing Oldowan Infill. Copyright 2000 Academic Press.

3D Visualization of Cultural Heritage Artefacts with Virtual Reality devices

Science.gov (United States)

Gonizzi Barsanti, S.; Caruso, G.; Micoli, L. L.; Covarrubias Rodriguez, M.; Guidi, G.

2015-08-01

Although 3D models are useful to preserve the information about historical artefacts, the potential of these digital contents are not fully accomplished until they are not used to interactively communicate their significance to non-specialists. Starting from this consideration, a new way to provide museum visitors with more information was investigated. The research is aimed at valorising and making more accessible the Egyptian funeral objects exhibited in the Sforza Castle in Milan. The results of the research will be used for the renewal of the current exhibition, at the Archaeological Museum in Milan, by making it more attractive. A 3D virtual interactive scenario regarding the "path of the dead", an important ritual in ancient Egypt, was realized to augment the experience and the comprehension of the public through interactivity. Four important artefacts were considered for this scope: two ushabty, a wooden sarcophagus and a heart scarab. The scenario was realized by integrating low-cost Virtual Reality technologies, as the Oculus Rift DK2 and the Leap Motion controller, and implementing a specific software by using Unity. The 3D models were implemented by adding responsive points of interest in relation to important symbols or features of the artefact. This allows highlighting single parts of the artefact in order to better identify the hieroglyphs and provide their translation. The paper describes the process for optimizing the 3D models, the implementation of the interactive scenario and the results of some test that have been carried out in the lab.

3D Visualization of Cultural Heritage Artefacts with Virtual Reality devices

Directory of Open Access Journals (Sweden)

S. Gonizzi Barsanti

2015-08-01

Full Text Available Although 3D models are useful to preserve the information about historical artefacts, the potential of these digital contents are not fully accomplished until they are not used to interactively communicate their significance to non-specialists. Starting from this consideration, a new way to provide museum visitors with more information was investigated. The research is aimed at valorising and making more accessible the Egyptian funeral objects exhibited in the Sforza Castle in Milan. The results of the research will be used for the renewal of the current exhibition, at the Archaeological Museum in Milan, by making it more attractive. A 3D virtual interactive scenario regarding the “path of the dead”, an important ritual in ancient Egypt, was realized to augment the experience and the comprehension of the public through interactivity. Four important artefacts were considered for this scope: two ushabty, a wooden sarcophagus and a heart scarab. The scenario was realized by integrating low-cost Virtual Reality technologies, as the Oculus Rift DK2 and the Leap Motion controller, and implementing a specific software by using Unity. The 3D models were implemented by adding responsive points of interest in relation to important symbols or features of the artefact. This allows highlighting single parts of the artefact in order to better identify the hieroglyphs and provide their translation. The paper describes the process for optimizing the 3D models, the implementation of the interactive scenario and the results of some test that have been carried out in the lab.

Artefacts in multimodal imaging of titanium, zirconium and binary titanium-zirconium alloy dental implants: an in vitro study.

Science.gov (United States)

Smeets, Ralf; Schöllchen, Maximilian; Gauer, Tobias; Aarabi, Ghazal; Assaf, Alexandre T; Rendenbach, Carsten; Beck-Broichsitter, Benedicta; Semmusch, Jan; Sedlacik, Jan; Heiland, Max; Fiehler, Jens; Siemonsen, Susanne

2017-02-01

To analyze and evaluate imaging artefacts induced by zirconium, titanium and titanium-zirconium alloy dental implants. Zirconium, titanium and titanium-zirconium alloy implants were embedded in gelatin and MRI, CT and CBCT were performed. Standard protocols were used for each modality. For MRI, line-distance profiles were plotted to quantify the accuracy of size determination. For CT and CBCT, six shells surrounding the implant were defined every 0.5 cm from the implant surface and histogram parameters were determined for each shell. While titanium and titanium-zirconium alloy induced extensive signal voids in MRI owing to strong susceptibility, zirconium implants were clearly definable with only minor distortion artefacts. For titanium and titanium-zirconium alloy, the MR signal was attenuated up to 14.1 mm from the implant. In CT, titanium and titanium-zirconium alloy resulted in less streak artefacts in comparison with zirconium. In CBCT, titanium-zirconium alloy induced more severe artefacts than zirconium and titanium. MRI allows for an excellent image contrast and limited artefacts in patients with zirconium implants. CT and CBCT examinations are less affected by artefacts from titanium and titanium-zirconium alloy implants compared with MRI. The knowledge about differences of artefacts through different implant materials and image modalities might help support clinical decisions for the choice of implant material or imaging device in the clinical setting.

Artefacts in multimodal imaging of titanium, zirconium and binary titanium–zirconium alloy dental implants: an in vitro study

Science.gov (United States)

Schöllchen, Maximilian; Aarabi, Ghazal; Assaf, Alexandre T; Rendenbach, Carsten; Beck-Broichsitter, Benedicta; Semmusch, Jan; Sedlacik, Jan; Heiland, Max; Fiehler, Jens; Siemonsen, Susanne

2017-01-01

Objectives: To analyze and evaluate imaging artefacts induced by zirconium, titanium and titanium–zirconium alloy dental implants. Methods: Zirconium, titanium and titanium–zirconium alloy implants were embedded in gelatin and MRI, CT and CBCT were performed. Standard protocols were used for each modality. For MRI, line–distance profiles were plotted to quantify the accuracy of size determination. For CT and CBCT, six shells surrounding the implant were defined every 0.5 cm from the implant surface and histogram parameters were determined for each shell. Results: While titanium and titanium–zirconium alloy induced extensive signal voids in MRI owing to strong susceptibility, zirconium implants were clearly definable with only minor distortion artefacts. For titanium and titanium–zirconium alloy, the MR signal was attenuated up to 14.1 mm from the implant. In CT, titanium and titanium–zirconium alloy resulted in less streak artefacts in comparison with zirconium. In CBCT, titanium–zirconium alloy induced more severe artefacts than zirconium and titanium. Conclusions: MRI allows for an excellent image contrast and limited artefacts in patients with zirconium implants. CT and CBCT examinations are less affected by artefacts from titanium and titanium–zirconium alloy implants compared with MRI. The knowledge about differences of artefacts through different implant materials and image modalities might help support clinical decisions for the choice of implant material or imaging device in the clinical setting. PMID:27910719

MRI with intraoral orthodontic appliance—a comparative in vitro and in vivo study of image artefacts at 1.5 T

Science.gov (United States)

Zachriat, C; Asbach, P; Blankenstein, K I; Peroz, I

2015-01-01

Objectives: We investigated artefacts caused from orthodontic appliances at 1.5-T MRI of the head and neck region and whether the image quality can be improved utilizing the artefact-minimizing sequence WARP. Methods: In vitro tests were performed by phantom measurements of different orthodontic devices applying different types of MR sequences [echoplanar imaging (EPI), turbo spin echo (TSE) and TSE-WARP, gradient echo (GRE)]. Two independent readers determined after calibration the level of artefacts. Subsequently, the interobserver agreement was calculated. The measurement of artefacts was based on the American Society for Testing Materials Standard F 2119-07. For in vivo imaging, one test person was scanned with an inserted multibracket appliance. The level of artefacts for 27 target regions was evaluated. Results: In vitro: ceramic brackets and ferromagnetic steel brackets produced artefact radii up to 1.12 and 7.40 cm, respectively. WARP reduced these artefacts by an average of 32.7%. The Bland–Altman-Plot indicated that maximum measurement differences of 3 mm have to be expected with two calibrated observers. In vivo: the EPI sequence for brain imaging was not analysable. The TSE sequence of the brain did not demonstrate artefacts except for the nasal cavity. Conversely, the TSE sequence of the cervical spine revealed severe artefacts in the midface region. The GRE sequence appeared to be more susceptible to artefacts than did the TSE sequence. Conclusions: In vitro measurements allow an estimation of the in vivo artefact size. Orthodontic appliances may often remain intraorally when performing MRI. WARP showed a more significant effect in vitro than in vivo. PMID:25734243

Effects of treatment with oxytocin, xylazine butorphanol, guaifenesin, acepromazine, and detomidine on esophageal manometric pressure in conscious horses.

Science.gov (United States)

Wooldridge, Anne A; Eades, Susan C; Hosgood, Giselle L; Moore, Rustin M

2002-12-01

To compare effects of oxytocin, acepromazine maleate, xylazine hydrochloride-butorphanol tartrate, guaifenesin, and detomidine hydrochloride on esophageal manometric pressure in horses. 8 healthy adult horses. A nasogastric tube, modified with 3 polyethylene tubes that exited at the postpharyngeal area, thoracic inlet, and distal portion of the esophagus, was fitted for each horse. Amplitude, duration, and rate of propagation of pressure waveforms induced by swallows were measured at 5, 10, 20, 30, and 40 minutes after administration of oxytocin, detomidine, acepromazine, xylazine-butorphanol, guaifenesin, or saline (0.9% NaCI) solution. Number of spontaneous swallows, spontaneous events (contractions that occurred in the absence of a swallow stimulus), and high-pressure events (sustained increases in baseline pressure of > 10 mm Hg) were compared before and after drug adminision. At 5 minutes after administration, detomidine increased waveform amplitude and decreased waveform duration at the thoracic inlet. At 10 minutes after administration, detomidine increased waveform duration at the thoracic inlet. Acepromazine administration increased the number of spontaneous events at the thoracic inlet and distal portion of the esophagus. Acepromazine and detomidine administration increased the number of high-pressure events at the thoracic inlet. Guaifenesin administration increased the number of spontaneous events at the thoracic inlet. Xylazine-butorphanol, detomidine, acepromazine, and guaifenesin administration decreased the number of spontaneous swallows. Detomidine, acepromazine, and a combination of xylazine butorphanol had the greatest effect on esophageal motility when evaluated manometrically. Reduction in spontaneous swallowing and changes in normal, coordinated peristaltic activity are the most clinically relevant effects.

Comparison of two ring artefact removal filters used for neutron tomography reconstruction

International Nuclear Information System (INIS)

Vontobel, P.

2007-01-01

Full text of publication follows: The reduction of ring artefacts in transmission tomography reconstruction, by filtering sino-grams, is a common practice for most radiation modalities. Using simulated and measured neutron transmission data, an analysis of two ring artefact suppression schemes is given. The choice of the ring filtering parameters has to take the noise characteristics of the measured raw projection data into account. Introduction The appearance of ring artefacts in transmission tomography data is quite common. They are due to deficiencies in the measured projections and show as vertical lines in the sinogram representation of all projections of a single slice. A vertical line in the sinogram is due to a single pixel or a group of n pixels on the detector, which is less or more sensitive than the average pixel and shows even after flat-field correction. Most annoying ring artefacts are due to partly dead pixels, which cannot be identified easily on the projection images. Their effect only show in the sinogram or later on the reconstructed slice images. Therefore ring artefact mitigation starts with the analysis of sinogram images or analysis of reconstructed slices. Analysis of two ring filtering algorithms: The first ring filtering method sums first sinogram rows (i.e. over all angles) and divides it by the number of rows (ave) and generate a smoothed version of this sum (smoothing width 3,5,7,9 pixels). The difference diff = ave - smooth(ave) is then subtracted from each row. This is a very simple and efficient correction scheme. The second method relies on morphological filtering the sinogram i.e. using a combination of a morphological 'Top hat' and a 'Bot hat' operation on the data. A filtering threshold is determined depending on the number of detected lines in the sinogram. Summary and conclusion: Using simulated an measured neutron transmission data two ring filtering algorithms are evaluated. A careful choice of filtering parameters is

Metal artefact reduction for a dental cone beam CT image using image segmentation and backprojection filters

International Nuclear Information System (INIS)

Mohammadi, Mahdi; Khotanlou, Hassan; Mohammadi, Mohammad

2011-01-01

Full text: Due to low dose delivery and fast scanning, the dental Cone Beam CT (CBCT) is the latest technology being implanted for a range of dental imaging. The presence of metallic objects including amalgam or gold fillings in the mouth produces an intuitive image for human jaws. The feasibility of a fast and accurate approach for metal artefact reduction for dental CBCT is investigated. The current study investigates the metal artefact reduction using image segmentation and modification of several sinigrams. In order to reduce metal effects such as beam hardening, streak artefact and intense noises, the application of several algorithms is evaluated. The proposed method includes three stages: preprocessing, reconstruction and post-processing. In the pre-processing stage, in order to reduce the noise level, several phase and frequency filters were applied. At the second stage, based on the specific sinogram achieved for each segment, spline interpolation and weighting backprojection filters were applied to reconstruct the original image. A three-dimensional filter was then applied on reconstructed images, to improve the image quality. Results showed that compared to other available filters, standard frequency filters have a significant influence in the preprocessing stage (ΔHU = 48 ± 6). In addition, with the streak artefact, the probability of beam hardening artefact increases. t e post-processing stage, the application of three-dimensional filters improves the quality of reconstructed images (See Fig. I). Conclusion The proposed method reduces metal artefacts especially where there are more than one metal implanted in the region of interest.

Influence of chest compression artefact on capnogram-based ventilation detection during out-of-hospital cardiopulmonary resuscitation.

Science.gov (United States)

Leturiondo, Mikel; Ruiz de Gauna, Sofía; Ruiz, Jesus M; Julio Gutiérrez, J; Leturiondo, Luis A; González-Otero, Digna M; Russell, James K; Zive, Dana; Daya, Mohamud

2018-03-01

Capnography has been proposed as a method for monitoring the ventilation rate during cardiopulmonary resuscitation (CPR). A high incidence (above 70%) of capnograms distorted by chest compression induced oscillations has been previously reported in out-of-hospital (OOH) CPR. The aim of the study was to better characterize the chest compression artefact and to evaluate its influence on the performance of a capnogram-based ventilation detector during OOH CPR. Data from the MRx monitor-defibrillator were extracted from OOH cardiac arrest episodes. For each episode, presence of chest compression artefact was annotated in the capnogram. Concurrent compression depth and transthoracic impedance signals were used to identify chest compressions and to annotate ventilations, respectively. We designed a capnogram-based ventilation detection algorithm and tested its performance with clean and distorted episodes. Data were collected from 232 episodes comprising 52 654 ventilations, with a mean (±SD) of 227 (±118) per episode. Overall, 42% of the capnograms were distorted. Presence of chest compression artefact degraded algorithm performance in terms of ventilation detection, estimation of ventilation rate, and the ability to detect hyperventilation. Capnogram-based ventilation detection during CPR using our algorithm was compromised by the presence of chest compression artefact. In particular, artefact spanning from the plateau to the baseline strongly degraded ventilation detection, and caused a high number of false hyperventilation alarms. Further research is needed to reduce the impact of chest compression artefact on capnographic ventilation monitoring. Copyright © 2017 Elsevier B.V. All rights reserved.

Beyond tokenistic participation: using representational artefacts to enable meaningful public participation in health service design.

Science.gov (United States)

Morrison, Cecily; Dearden, Andy

2013-10-01

A number of recent policies promote public participation in health service design. Yet, a growing literature has articulated a gap between policy aims and actual practice resulting in public participation becoming tokenistic. Drawing on theory from participatory design, we argue that choosing appropriate artefacts to act as representations can structure discussions between public participants and health professionals in ways that both groups find meaningful and valid. Through a case study of a service improvement project in outpatient services for older people, we describe three representational artefacts: emotion maps, stories, and tracing paper, and explain how they helped to mediate interactions between public participants and health professionals. We suggest that using such representational artefacts can provide an alternative approach to participation that stands in contrast to the current focus on the professionalisation of public participants. We conclude that including participatory designers in projects, to chose or design appropriate representational artefacts, can help to address the policy-practice gap of including public participants in health service design. Copyright © 2013 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

An Evaluation View of an Ensemble Artefact for Decision Support using Action Design Research

Directory of Open Access Journals (Sweden)

Dale MacKrell

2016-11-01

Full Text Available This paper investigates the integration of content, context and process (CCP into the Action Design Research (ADR framework to account for the interplay of organisational issues in artefact design and development. The investigation is conducted through a case study in which successive ICT student teams incrementally build, over several semesters, a tailored, low cost business intelligence (BI system as an ensemble artefact for an organisation in the not-for-profit (NFP sector. During project development, CCP’s human-centred approach to evaluation complements ADR’s more prescribed technology-driven software testing. The integration of CCP into ADR as an evaluation view offers an holistic approach to assessing an ensemble artefact. The resultant conceptual framework is presented as a model with an explication of unexpected design and research outcomes.

Magnetic resonance angiography with ultrashort echo times reduces the artefact of aneurysm clips

International Nuclear Information System (INIS)

Goenner, F.; Heid, O.; Remonda, L.; Schroth, G.; Loevblad, K.O.; Guzman, R.; Barth, A.

2002-01-01

We evaluated the ability of an ultrashort echo time (TE) three-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography (MRA) sequence to reduce the metal artefact of intracranial aneurysm clips and to display adjacent cerebral arteries. In five patients (aged 8-72 years) treated with Elgiloy or Phynox aneurysm clips we prospectively performed a conventional (TE 6.0 ms) and a new ultrashort TE (TE 2.4 ms) 3D TOF MRA. We compared the diameter of the clip-induced susceptibility artefact and the detectability of flow in adjacent vessels. The mean artefact diameter was 22.3±6.4 mm (range 14-38 mm) with the ultrashort TE and 27.7±6.4 mm (range 19-45 mm) with the conventional MRA (P<0.0001). This corresponded to a diameter reduction of 19.5±9.2%. More parts of adjacent vessels were detected, but with less intense flow signal. The aneurysm dome and neck remained within the area of signal loss and were therefore not displayed. Ultrashort TE MRA is a noninvasive and fast method for improving detection of vessels adjacent to clipped intracranial aneurysms, by reducing clip-induced susceptibility artefact. The method cannot, however, be used to show remnants of the aneurysm neck or sac as a result of imperfect clipping. (orig.)

Analysis artefacts of the INS-IGF2 fusion transcript

DEFF Research Database (Denmark)

Wernersson, Rasmus; Frogne, Thomas; Rescan, Claude

2015-01-01

Background: In gene expression analysis, overlapping genes, splice variants, and fusion transcripts are potential sources of data analysis artefacts, depending on how the observed intensity is assigned to one, or more genes. We here exemplify this by an in-depth analysis of the INS-IGF2 fusion...... transcript, which has recently been reported to be among the highest expressed transcripts in human pancreatic beta cells and its protein indicated as a novel autoantigen in Type 1 Diabetes. Results: Through RNA sequencing and variant specific qPCR analyses we demonstrate that the true abundance of INS-IGF2...... is >20,000 fold lower than INS in human beta cells, and we suggest an explanation to the nature of the artefacts which have previously led to overestimation of the gene expression level in selected studies. We reinvestigated the previous reported findings of detection of INS-IGF2 using antibodies both...

A study of artefacts in simultaneous PET and MR imaging using a prototype MR compatible PET scanner

International Nuclear Information System (INIS)

Slates, R.B.; Farahani, K.; Marsden, P.K.; Taylor, J.; Summers, P.E.; Williams, S.; Beech, J.

1999-01-01

We have assessed the possibility of artefacts that can arise in attempting to perform simultaneous positron emission tomography (PET) and magnetic resonance imaging (MRI) using a small prototype MR compatible PET scanner (McPET). In these experiments, we examine MR images for any major artefacts or loss in image quality due to inhomogeneities in the magnetic field, radiofrequency interference or susceptibility effects caused by operation of the PET system inside the MR scanner. In addition, possible artefacts in the PET images caused by the static and time-varying magnetic fields or radiofrequency interference from the MR system were investigated. Biological tissue and a T 2 -weighted spin echo sequence were used to examine susceptibility artefacts due to components of the McPET scanner (scintillator, optical fibres) situated in the MR field of view. A range of commonly used MR pulse sequences was studied while acquiring PET data to look for possible artefacts in either the PET or MR images. Other than a small loss in signal-to-noise using gradient echo sequences, there was no significant interaction between the two imaging systems. Simultaneous PET and MR imaging of simple phantoms was also carried out in different MR systems with field strengths ranging from 0.2 to 4.7 T. The results of these studies demonstrate that it is possible to acquire PET and MR images simultaneously, without any significant artefacts or loss in image quality, using our prototype MR compatible PET scanner. (author)

Influence of metallic dental implants and metal artefacts on dose calculation accuracy.

Science.gov (United States)

Maerz, Manuel; Koelbl, Oliver; Dobler, Barbara

2015-03-01

Metallic dental implants cause severe streaking artefacts in computed tomography (CT) data, which inhibit the correct representation of shape and density of the metal and the surrounding tissue. The aim of this study was to investigate the impact of dental implants on the accuracy of dose calculations in radiation therapy planning and the benefit of metal artefact reduction (MAR). A second aim was to determine the treatment technique which is less sensitive to the presence of metallic implants in terms of dose calculation accuracy. Phantoms consisting of homogeneous water equivalent material surrounding dental implants were designed. Artefact-containing CT data were corrected using the correct density information. Intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans were calculated on corrected and uncorrected CT data and compared to 2-dimensional dose measurements using GafChromic™ EBT2 films. For all plans the accuracy of dose calculations is significantly higher if performed on corrected CT data (p = 0.015). The agreement of calculated and measured dose distributions is significantly higher for VMAT than for IMRT plans for calculations on uncorrected CT data (p = 0.011) as well as on corrected CT data (p = 0.029). For IMRT and VMAT the application of metal artefact reduction significantly increases the agreement of dose calculations with film measurements. VMAT was found to provide the highest accuracy on corrected as well as on uncorrected CT data. VMAT is therefore preferable over IMRT for patients with metallic implants, if plan quality is comparable for the two techniques.

Influence of metallic dental implants and metal artefacts on dose calculation accuracy

International Nuclear Information System (INIS)

Maerz, Manuel; Koelbl, Oliver; Dobler, Barbara

2015-01-01

Metallic dental implants cause severe streaking artefacts in computed tomography (CT) data, which inhibit the correct representation of shape and density of the metal and the surrounding tissue. The aim of this study was to investigate the impact of dental implants on the accuracy of dose calculations in radiation therapy planning and the benefit of metal artefact reduction (MAR). A second aim was to determine the treatment technique which is less sensitive to the presence of metallic implants in terms of dose calculation accuracy. Phantoms consisting of homogeneous water equivalent material surrounding dental implants were designed. Artefact-containing CT data were corrected using the correct density information. Intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans were calculated on corrected and uncorrected CT data and compared to 2-dimensional dose measurements using GafChromic trademark EBT2 films. For all plans the accuracy of dose calculations is significantly higher if performed on corrected CT data (p = 0.015). The agreement of calculated and measured dose distributions is significantly higher for VMAT than for IMRT plans for calculations on uncorrected CT data (p = 0.011) as well as on corrected CT data (p = 0.029). For IMRT and VMAT the application of metal artefact reduction significantly increases the agreement of dose calculations with film measurements. VMAT was found to provide the highest accuracy on corrected as well as on uncorrected CT data. VMAT is therefore preferable over IMRT for patients with metallic implants, if plan quality is comparable for the two techniques. (orig.) [de

What Then Happens When Interaction is Not Possible: The Virtuosic Interpretation of Ergodic Artefacts

Directory of Open Access Journals (Sweden)

Miguel Carvalhais

2015-11-01

Full Text Available Procedural systems allow unique modes of authorship and singular aesthetic experiences. As creators and users of these systems, we need to be aware that their aesthetic potential is not solely defined by interaction but that interpretation, and the capacity to understand and simulate the processes taking place within these artefacts is highly significant. This paper argues that although direct interaction is usually the most discernible component in the relationship between ergodic artefacts and their users, ergodicity does not necessarily imply interaction. Non-interactive procedural artefacts may allow the development of ergodic experiences through interpretation, and the probing of the system by its reader through simulations. We try to set the grounds for designing towards virtuosic interpretation, an activity that we may describe as the ergodic experience developed by means of mental simulation through the development of theories of systems.

Transforming Artefacts into Digital Heritage

DEFF Research Database (Denmark)

Otto, Ton; Hardy, Dianna

2016-01-01

a genuine transformation of the artefacts that opens up new possibilities of use. These include providing access to and facilitating the reappropriation of cultural knowledge stored elsewhere, maintaining and developing a living digital cultural heritage, and gathering, sharing and transferring knowledge...... that is available within Aboriginal communities. In this paper we examine different types of digital repositories and we assess their suitability for use by Aboriginal communities. We classify a number of institutional archiving systems and analyse in some detail two interactive systems that were specifically...... designed for use by Aboriginal communities. The paper ends with a set of recommendations for designing digital databases for Indigenous usage....

Triangular dislocation: an analytical, artefact-free solution

Science.gov (United States)

Nikkhoo, Mehdi; Walter, Thomas R.

2015-05-01

Displacements and stress-field changes associated with earthquakes, volcanoes, landslides and human activity are often simulated using numerical models in an attempt to understand the underlying processes and their governing physics. The application of elastic dislocation theory to these problems, however, may be biased because of numerical instabilities in the calculations. Here, we present a new method that is free of artefact singularities and numerical instabilities in analytical solutions for triangular dislocations (TDs) in both full-space and half-space. We apply the method to both the displacement and the stress fields. The entire 3-D Euclidean space {R}3 is divided into two complementary subspaces, in the sense that in each one, a particular analytical formulation fulfils the requirements for the ideal, artefact-free solution for a TD. The primary advantage of the presented method is that the development of our solutions involves neither numerical approximations nor series expansion methods. As a result, the final outputs are independent of the scale of the input parameters, including the size and position of the dislocation as well as its corresponding slip vector components. Our solutions are therefore well suited for application at various scales in geoscience, physics and engineering. We validate the solutions through comparison to other well-known analytical methods and provide the MATLAB codes.

Comparison of CT and MRI artefacts from coils and vascular plugs used for portal vein embolization

Energy Technology Data Exchange (ETDEWEB)

Geisel, Dominik, E-mail: dominik.geisel@charite.de [Department of Diagnostic and Interventional Radiology, Charité, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353 Berlin (Germany); Gebauer, Bernhard [Department of Diagnostic and Interventional Radiology, Charité, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353 Berlin (Germany); Malinowski, Maciej; Stockmann, Martin [Department of General, Visceral and Transplantation Surgery, Charité, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353 Berlin (Germany); Denecke, Timm [Department of Diagnostic and Interventional Radiology, Charité, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353 Berlin (Germany)

2014-04-15

Purpose: To retrospectively analyze the degree of artefacts in CT and MRI scans caused by coils and vascular plugs used for portal vein embolization (PVE). Materials and methods: All patients who underwent PVE between July 2011 and December 2012 and received either plug or coil embolization additional to particle embolization were retrospectively analyzed. Artefacts causes by embolization materials were measured in CT and MRI scans following PVE. Results: The sum of the artefact diameters caused from coils was significantly higher in CT (188.3 ± 26.1 mm) than in MRI T1 (50.5 ± 6.5 mm) or T2 imaging (39.5 ± 9.7 mm) (P < 0.05). In MRI, the diameter in T1 and T2 sequences did not differ significantly (P = 0.977). The sum of the artefact diameters from vascular plugs in MRI T1 sequences (62.5 ± 8.7 mm) was significantly higher than in CT (46.6 ± 4.8 mm; P < 0.05) and MRI T2 sequences (52.8 ± 3.8 mm; P < 0.05). Conclusion: PVE with particles and vascular plug causes significantly fewer artefacts than PVE with particles and coils on CT scans following embolization, which can be important in the event of vascular complications or in follow-up scans, should the patient become unresectable.

An investigation of inconsistent projections and artefacts in multi-pinhole SPECT with axially aligned pinholes

International Nuclear Information System (INIS)

Kench, P L; Meikle, S R; Lin, J; Gregoire, M C

2011-01-01

Multiple pinholes are advantageous for maximizing the use of the available field of view (FOV) of compact small animal single photon emission computed tomography (SPECT) detectors. However, when the pinholes are aligned axially to optimize imaging of extended objects, such as rodents, multiplexing of the pinhole projections can give rise to inconsistent data which leads to 'ghost point' artefacts in the reconstructed volume. A novel four pinhole collimator with a baffle was designed and implemented to eliminate these inconsistent projections. Simulation and physical phantom studies were performed to investigate artefacts from axially aligned pinholes and the efficacy of the baffle in removing inconsistent data and, thus, reducing reconstruction artefacts. SPECT was performed using a Defrise phantom to investigate the impact of collimator design on FOV utilization and axial blurring effects. Multiple pinhole SPECT acquired with a baffle had fewer artefacts and improved quantitative accuracy when compared to SPECT acquired without a baffle. The use of four pinholes positioned in a square maximized the available FOV, increased acquisition sensitivity and reduced axial blurring effects. These findings support the use of a baffle to eliminate inconsistent projection data arising from axially aligned pinholes and improve small animal SPECT reconstructions.

Improving biofeedback for the treatment of fecal incontinence in women: implementation of a standardized multi-site manometric biofeedback protocol.

Science.gov (United States)

Markland, A D; Jelovsek, J E; Whitehead, W E; Newman, D K; Andy, U U; Dyer, K; Harm-Ernandes, I; Cichowski, S; McCormick, J; Rardin, C; Sutkin, G; Shaffer, A; Meikle, S

2017-01-01

Standardized training and clinical protocols using biofeedback for the treatment of fecal incontinence (FI) are important for clinical care. Our primary aims were to develop, implement, and evaluate adherence to a standardized protocol for manometric biofeedback to treat FI. In a Pelvic Floor Disorders Network (PFDN) trial, participants were enrolled from eight PFDN clinical centers across the United States. A team of clinical and equipment experts developed biofeedback software on a novel tablet computer platform for conducting standardized anorectal manometry with separate manometric biofeedback protocols for improving anorectal muscle strength, sensation, and urge resistance. The training protocol also included education on bowel function, anal sphincter exercises, and bowel diary monitoring. Study interventionists completed online training prior to attending a centralized, standardized certification course. For the certification, expert trainers assessed the ability of the interventionists to perform the protocol components for a paid volunteer who acted as a standardized patient. Postcertification, the trainers audited interventionists during trial implementation to improve protocol adherence. Twenty-four interventionists attended the in-person training and certification, including 46% advanced practice registered nurses (11/24), 50% (12/24) physical therapists, and 4% physician assistants (1/24). Trainers performed audio audits for 88% (21/24), representing 84 audited visits. All certified interventionists met or exceeded the prespecified 80% pass rate for the audit process, with an average passing rate of 93%. A biofeedback protocol can be successfully imparted to experienced pelvic floor health care providers from various disciplines. Our process promoted high adherence to a standard protocol and is applicable to many clinical settings. © 2016 John Wiley & Sons Ltd.

Reduced artefacts and improved assessment of hyperintense brain lesions with BLADE MR imaging in patients with neurofibromatosis type 1

Energy Technology Data Exchange (ETDEWEB)

Kalle, Thekla von; Fabig-Moritz, Claudia; Mueller-Abt, Peter; Zieger, Michael; Winkler, Peter [Department of Paediatric Radiology, Stuttgart (Germany); Blank, Bernd [Haematology and Immunology, Department of Paediatric Oncology, Stuttgart (Germany); Wohlfarth, Katrin [Siemens Healthcare Sector, Erlangen (Germany)

2009-11-15

Assessment of small brain lesions in children is often compromised by pulsation, flow or movement artefacts. MRI with a rotating blade-like k-space covering (BLADE, PROPELLER) can compensate for these artefacts. We compared T2-weighted FLAIR images that were acquired with different k-space trajectories (conventional Cartesian and BLADE) to evaluate the impact of BLADE technique on the delineation of small or low-contrast brain lesions. The subject group comprised 26 children with neurofibromatosis type 1 (NF 1), who had been routinely scanned at 1.5 T for optic pathway gliomas with both techniques and who had the typical hyperintense brain lesions seen in NF 1. Four experienced radiologists retrospectively compared unlabelled 4-mm axial images with respect to the presence of artefacts, visibility of lesions, quality of contour and contrast. Both techniques were comparable in depicting hyperintense lesions as small as 2 mm independent of contrast and edge definition. Pulsation and movement artefacts were significantly less common with BLADE k-space trajectory. In 7 of 26 patients (27%), lesions and artefacts were rated as indistinguishable in conventional FLAIR, but not in BLADE FLAIR images. BLADE imaging significantly improved the depiction of lesions in T2-W FLAIR images due to artefact reduction especially in the posterior fossa. (orig.)

Reduced artefacts and improved assessment of hyperintense brain lesions with BLADE MR imaging in patients with neurofibromatosis type 1

International Nuclear Information System (INIS)

Kalle, Thekla von; Fabig-Moritz, Claudia; Mueller-Abt, Peter; Zieger, Michael; Winkler, Peter; Blank, Bernd; Wohlfarth, Katrin

2009-01-01

Assessment of small brain lesions in children is often compromised by pulsation, flow or movement artefacts. MRI with a rotating blade-like k-space covering (BLADE, PROPELLER) can compensate for these artefacts. We compared T2-weighted FLAIR images that were acquired with different k-space trajectories (conventional Cartesian and BLADE) to evaluate the impact of BLADE technique on the delineation of small or low-contrast brain lesions. The subject group comprised 26 children with neurofibromatosis type 1 (NF 1), who had been routinely scanned at 1.5 T for optic pathway gliomas with both techniques and who had the typical hyperintense brain lesions seen in NF 1. Four experienced radiologists retrospectively compared unlabelled 4-mm axial images with respect to the presence of artefacts, visibility of lesions, quality of contour and contrast. Both techniques were comparable in depicting hyperintense lesions as small as 2 mm independent of contrast and edge definition. Pulsation and movement artefacts were significantly less common with BLADE k-space trajectory. In 7 of 26 patients (27%), lesions and artefacts were rated as indistinguishable in conventional FLAIR, but not in BLADE FLAIR images. BLADE imaging significantly improved the depiction of lesions in T2-W FLAIR images due to artefact reduction especially in the posterior fossa. (orig.)

FT-Raman and FT-Infrared investigations of archaeological artefacts from Foeni Neolithic site (Banat, Romania

Directory of Open Access Journals (Sweden)

Simona Cîntă Pînzaru

2008-08-01

Full Text Available An impressive collection of chert artefacts from the Foeni Neolithic archaeological site (Timiş County, Banat region, Romania is hosted by the Banat Museum in Timişoara. A representative set of seven specimens was non-destructively investigated using FT-Raman and ATR-FT-IR spectroscopy. The research was carried out for checking if these readily-available, non-destructive, fast, and cheap methods, which do not require preliminary sample preparation could provide significant information for characterizing the mineral composition of chert artefacts. Based on vibrational data, it was confirmed that the raw material was represented by microcrystalline quartz and moganite, with local concentrations of accessory minerals (calcite, dolomite, and clay minerals. In spite of their wide macroscopic heterogeneity (colour, transparency, based on single point FT-Raman measurements the chert artefacts could not be assigned to distinctive groups of raw silica materials, in order to provide specific arguments for provenance studies. However, the presence of specific accessory minerals (dolomite, illite pointed to distinctive genetic conditions in the case of one lithic material. Sets of measurements (mapping are required for statistically characterizing each artefact specimen. IR data were less significant, due to the rough surface texture of the specimens in contact with the ZnSe crystal of the ATR-FT-IR module. However, illite was identified based solely on its contribution to the IR spectrum. This pioneering study on chert artefacts from Romania based on optical spectroscopic methods shows that there are good premises for a systematic investigation of highly-valuable museum collections, in particular in terms of chert geology.

Persistent Artefacts in an Online Classroom: The Value of a Dynamic Learning Archive | Artefacts persistants dans une salle de classe en ligne : la valeur d’une archive dynamique de l’apprentissage

Directory of Open Access Journals (Sweden)

Stuart C. Berry

2016-04-01

Full Text Available This paper summarizes a multi-year research project that examines the use and value of visible and persistent artefacts within an online learning environment. This study is framed within elements of a business management theory. Changes to an online learning environment are documented as well as an examination of the impact of these changes on the learning process. The study also shows the impact of learner engagement with artefacts over the life of multiple iterations of a course within this socially networked online learning space. Two significant outcomes emerged: 1. How the use of a socially networked online learning environment can offer a rich and supportive place for teaching and learning; and 2. That students in this study support the inclusion of an archive containing artefacts from learners in prior iterations of a course. The connection between the inclusion of this archive and the impact of a socially networked online learning environment will be demonstrated throughout. Cet article résume un projet de recherche sur plusieurs années, examinant l’utilisation et la valeur des artefacts visibles et persistants au sein d’un environnement d’apprentissage en ligne. Cette étude a été structurée selon des éléments d’une théorie de la gestion des affaires. Les modifications à l’environnement d’apprentissage en ligne sont documentées, ainsi que l’examen de l’incidence de ces modifications sur le processus d’apprentissage. L’étude montre aussi l’impact de l’engagement de l’apprenant avec les artefacts sur plusieurs itérations d’un cours dans un espace d’apprentissage en ligne doté de réseaux sociaux. Deux résultats importants ont émergé : 1. un espace d’apprentissage en ligne doté de réseaux sociaux peut offrir un endroit riche et soutenant pour l’enseignement et l’apprentissage; et 2. les étudiants dans cette étude sont favorables à l’inclusion d’une archive rassemblant les

Metabolic cold adaptation of polar fish based on measurements of aerobic oxygen consumption: fact or artefact? Artefact!

DEFF Research Database (Denmark)

Steffensen, John Fleng

2002-01-01

Whether metabolic cold adaptation in polar fish, based on measurements of aerobic standard metabolic rate, is a fact or an artefact has been a dispute since Holeton asked the question in 1974. So far polar fish had been considered to be metabolically cold adapted because they were reported to have...... a considerably elevated resting oxygen consumption, or standard metabolic rate, compared with oxygen consumption values of tropical or temperate fish extrapolated to similar low polar temperatures. Recent experiments on arctic and Antarctic fish, however, do not show elevated resting aerobic oxygen consumption...

Investigation of archaeological metal artefacts by laser-induced breakdown spectroscopy (LIBS)

Science.gov (United States)

Tankova, V.; Malcheva, G.; Blagoev, K.; Leshtakov, L.

2018-03-01

In this work, laser-induced breakdown spectroscopy was applied to determining the elemental composition of a set of ancient bronze artefacts dated from the Late Bronze Age and Early Iron Age (14th – 10th century BC). We used a Nd:YAG laser at 1064 nm with pulse duration of 10 ns and energy of 10 mJ and determined the elemental composition of the bronze alloy that was used in manufacturing the samples under study. The concentrations of tin and lead in the bulk of the examined materials was estimated after generating calibration curves for a set of four standard samples. The preliminary results of the analysis will provide information on the artefacts provenance and on the production process.

fMRI Artefact Rejection and Sleep Scoring Toolbox

Directory of Open Access Journals (Sweden)

Yves Leclercq

2011-01-01

Full Text Available We started writing the “fMRI artefact rejection and sleep scoring toolbox”, or “FAST”, to process our sleep EEG-fMRI data, that is, the simultaneous recording of electroencephalographic and functional magnetic resonance imaging data acquired while a subject is asleep. FAST tackles three crucial issues typical of this kind of data: (1 data manipulation (viewing, comparing, chunking, etc. of long continuous M/EEG recordings, (2 rejection of the fMRI-induced artefact in the EEG signal, and (3 manual sleep-scoring of the M/EEG recording. Currently, the toolbox can efficiently deal with these issues via a GUI, SPM8 batching system or hand-written script. The tools developed are, of course, also useful for other EEG applications, for example, involving simultaneous EEG-fMRI acquisition, continuous EEG eye-balling, and manipulation. Even though the toolbox was originally devised for EEG data, it will also gracefully handle MEG data without any problem. “FAST” is developed in Matlab as an add-on toolbox for SPM8 and, therefore, internally uses its SPM8-meeg data format. “FAST” is available for free, under the GNU-GPL.

Prospective ECG triggering reduces prosthetic heart valve-induced artefacts compared with retrospective ECG gating on 256-slice CT

NARCIS (Netherlands)

Symersky, P.; Habets, J.; Westers, P.; Mol, de B.A.J.M.; Prokop, M.; Budde, R.P.J.

2012-01-01

Objectives Multidetector computed tomography (MDCT) has diagnostic value for the evaluation of prosthetic heart valve (PHV) dysfunction but it is hampered by artefacts. We hypothesised that image acquisition using prospective triggering instead of retrospective gating would reduce artefacts related

On the feasibility of establishing the provenance of Australian Aboriginal artefacts using synchrotron radiation X-ray diffraction and proton-induced X-ray emission

International Nuclear Information System (INIS)

Creagh, D.C.; Kubik, M.E.; Sterns, M.

2007-01-01

Museums and galleries in Australia have extensive collections of Aboriginal artefacts in their custody. In particular, the National Museum of Australia and the National Gallery of Australia are custodians of works of very considerable significance, in both cultural and financial terms. Art fraud can occur, documentation relating to artefacts can be mislaid, or the artefacts can be incorrectly filed. Because of this, it has become essential to establish protocols for the objective determination of the provenance of artefacts through scientific tests. For the work reported here we are concerned with the comparison of very small quantities of materials, paint scrapings from artefacts. Scrapings from artefacts of unknown provenance are compared with those from artefacts of known provenance, and the database established using an extended set of analytical techniques by Kubik. We describe here our use of synchrotron radiation X-ray diffraction (SR-XRD) to determine the mineral phase compositions of very small amounts of pigment material (<50 μg), and the use of PIXE to give their atomic compositions to a threshold level of 1 ppm for similar masses of material

Influence of the in-plane artefact in chest tomosynthesis on pulmonary nodule size measurements

International Nuclear Information System (INIS)

Soederman, Christina; Allansdotter Johnsson, Aase; Vikgren, Jenny; Rossi Norrlund, Rauni; Molnar, David; Svalkvist, Angelica; Maansson, Lars Gunnar; Baath, Magnus

2016-01-01

The aim of the present study was to investigate how the in-plane artefact present in the scan direction around structures in tomosynthesis images should be managed when measuring the size of nodules in chest tomosynthesis images in order to achieve acceptable measurement accuracy. Data from measurements, performed by radiologists, of the longest diameter of artificial nodules inserted in chest tomosynthesis images were used. The association between the measurement error and the direction of the longest nodule diameter, relative to the scan direction, was evaluated using the Kendall rank correlation coefficient. All of the radiologists had chosen to not include the artefact in the measurements. Significant association between measurement error and the direction of the longest diameter was found for nodules larger than 12 mm, which indicates that, for these nodules, there is a risk of underestimating the nodule size if the in-plane artefact is omitted from manual diameter measurements. (authors)

Corrosion of archaeological iron artefacts compared to modern iron at the waterlogged site Nydam, Denmark

International Nuclear Information System (INIS)

Matthiesen, Henning; Gregory, David; Soerensen, Birgit; Hilbert, Rischel Lisbeth

2004-01-01

Since 1859 several archaeological excavations have been carried out in Nydam, Denmark revealing a wealth of military equipment sacrificed in the period 200 - 500 AD. During the 1990's more than 16000 artefacts of mainly wood and iron were excavated within an area of only 600 m 2 . Due to the volume of finds it was decided in 1997 to stop further excavations. At the same time a study program was initiated at the National Museum to evaluate the feasibility of preserving the remaining artefacts in situ for a prolonged period. The study comprises all materials present in Nydam, but this presentation focuses solely on the iron objects. A three-pronged approach has been used in the studies in Nydam: 1) Studies of the excavated artefacts, including the composition of corrosion products and a mapping of their exact state of preservation. 2) Use of modern iron samples placed in the soil for studies of weight loss, corrosion potential, electrochemical impedance spectroscopy and electrical resistivity. 3) Measurements of environmental parameters such as water level, redox potential, oxygen concentration, soil pH, and the concentration of a range of dissolved species in the pore water. This presentation shows some of the results obtained during the seven years of studies at the site. It is demonstrated how the three pronged approach is useful in understanding not only the current corrosion rate and threats against the artefacts but also the corrosion history, i.e. when were the deterioration patterns and corrosion products observed today actually formed. The corrosion rates for archaeological artefacts and modern analogues are compared and briefly discussed. (authors)

The role of movies in Norwegian textbooks. A study of film as artefact in religious education

Directory of Open Access Journals (Sweden)

Jon Magne Vestøl

2012-12-01

Full Text Available Drawing on perspectives on educational design, this article investigates the role of movies in Norwegian secondary school textbooks on religious education, including teachers’ handbooks and textbook websites. All passages containing references to films or movies have been included in the analysis. The distribution of references indicates that a film is an optional artefact and that movies are drawn mainly from a Western cinematic tradition and are related to topics such as Christianity and ethics. When textbook assignments introduce movies as artefacts mediating the understanding of religious issues, information about the message and the artistic role of the film seems to be downplayed. This indicates a need for reflection on how artefacts such as films are introduced into educational activity.

The value of posterior levator repair in the treatment of anorectal incontinence due to rectal prolapse--a clinical and manometric study.

Science.gov (United States)

Köhler, A; Athanasiadis, S

2001-04-01

When treating a complete rectal prolapse, the most important objective is elimination of the prolapse. In addition, restoration of sufficient anorectal continence is extremely important for the patients. We examined the value of posterior levator repair with respect to stabilization of the pelvic floor and to improvement in anorectal incontinence. In patients with disabling anorectal incontinence, a posterior levatorplasty can be concomitantly performed during operative removal of the prolapse. To facilitate evaluation of the operative results, we implemented a scoring system to judge the patients' subjective symptoms of incontinence; in addition, we performed manometric measurements of resting and squeezing pressures of the anal sphincter to objectify the anorectal incontinence. From 1991 to 1997, 84 patients (mean age 65+/-10 years, 38-91 years; 79 women, 5 men) with complete rectal prolapse and severe incontinence were operatively treated; corresponding follow-ups were done. The following procedures were performed: Frykmann-Goldberg, 28 patients; Wells, 18 patients; Ripstein, 22 patients; and perineal proctectomy, 16 patients. Incontinence for liquid and solid stools was present in all of these patients. Posterior levatorplasty was implemented in 38 patients, and in this group we found significantly better postoperative results, both clinically and in the manometric measurements. Continence was improved by 84% in the group with levatorplasty, but improvement was only 67% in the other group (Pdisadvantages. For this reason, levatorplasty can be part of operative procedures implemented in the treatment of a complete rectal prolapse accompanied by disabling anorectal incontinence.

Quantifying metal artefact reduction using virtual monochromatic dual-layer detector spectral CT imaging in unilateral and bilateral total hip prostheses

Energy Technology Data Exchange (ETDEWEB)

Wellenberg, R.H.H., E-mail: r.h.wellenberg@amc.uva.nl [Department of Radiology, Academic Medical Centre, Amsterdam (Netherlands); Boomsma, M.F., E-mail: m.f.boomsma@isala.nl [Department of Radiology, Isala, Zwolle (Netherlands); Osch, J.A.C. van, E-mail: j.a.c.van.osch@isala.nl [Department of Radiology, Isala, Zwolle (Netherlands); Vlassenbroek, A., E-mail: alain.vlassenbroek@philips.com [Philips Medical Systems, Brussels (Belgium); Milles, J., E-mail: julien.milles@philips.com [Philips Medical Systems, Eindhoven (Netherlands); Edens, M.A., E-mail: m.a.edens@isala.nl [Department of Innovation and Science, Isala, Zwolle (Netherlands); Streekstra, G.J., E-mail: g.j.streekstra@amc.uva.nl [Department of Radiology, Academic Medical Centre, Amsterdam (Netherlands); Slump, C.H., E-mail: c.h.slump@utwente.nl [MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede (Netherlands); Maas, M., E-mail: m.maas@amc.uva.nl [Department of Radiology, Academic Medical Centre, Amsterdam (Netherlands)

2017-03-15

Highlights: • Dual-layer detector CT reduces metal artefacts at high monochromatic energies (keV). • 130 keV images were optimal based on quantitative analysis on CNRs. • Optimal keVs varied from 74 to 150 keV for different hip prostheses configurations. • The Titanium alloy resulted in less severe artefacts compared to the Cobalt alloy. • Severe metal artefacts, caused by extensive photon-starvation, were not reduced. - Abstract: Purpose: To quantify the impact of prosthesis material and design on the reduction of metal artefacts in total hip arthroplasties using virtual monochromatic dual-layer detector Spectral CT imaging. Methods: The water-filled total hip arthroplasty phantom was scanned on a novel 128-slice Philips IQon dual-layer detector Spectral CT scanner at 120-kVp and 140-kVp at a standard computed tomography dose index of 20.0 mGy. Several unilateral and bilateral hip prostheses consisting of different metal alloys were inserted and combined which were surrounded by 18 hydroxyapatite calcium carbonate pellets representing bone. Images were reconstructed with iterative reconstruction and analysed at monochromatic energies ranging from 40 to 200 keV. CT numbers in Hounsfield Units (HU), noise measured as the standard deviation in HU, signal-to-noise-ratios (SNRs) and contrast-to-noise-ratios (CNRs) were analysed within fixed regions-of-interests placed in and around the pellets. Results: In 70 and 74 keV virtual monochromatic images the CT numbers of the pellets were similar to 120-kVp and 140-kVp polychromatic results, therefore serving as reference. A separation into three categories of metal artefacts was made (no, mild/moderate and severe) where pellets were categorized based on HU deviations. At high keV values overall image contrast was reduced. For mild/moderate artefacts, the highest average CNRs were attained with virtual monochromatic 130 keV images, acquired at 140-kVp. Severe metal artefacts were not reduced. In 130 keV images

Quality Enhancement and Nerve Fibre Layer Artefacts Removal in Retina Fundus Images by Off Axis Imaging

Energy Technology Data Exchange (ETDEWEB)

Giancardo, Luca [ORNL; Meriaudeau, Fabrice [ORNL; Karnowski, Thomas Paul [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK); Tobin Jr, Kenneth William [ORNL; Chaum, Edward [University of Tennessee, Knoxville (UTK)

2011-01-01

Retinal fundus images acquired with non-mydriatic digital fundus cameras are a versatile tool for the diagnosis of various retinal diseases. Because of the ease of use of newer camera models and their relative low cost, these cameras are employed worldwide by retina specialists to diagnose diabetic retinopathy and other degenerative diseases. Even with relative ease of use, the images produced by these systems sometimes suffer from reflectance artefacts mainly due to the nerve fibre layer (NFL) or other camera lens related reflections. We propose a technique that employs multiple fundus images acquired from the same patient to obtain a single higher quality image without these reflectance artefacts. The removal of bright artefacts, and particularly of NFL reflectance, can have great benefits for the reduction of false positives in the detection of retinal lesions such as exudate, drusens and cotton wool spots by automatic systems or manual inspection. If enough redundant information is provided by the multiple images, this technique also compensates for a suboptimal illumination. The fundus images are acquired in straightforward but unorthodox manner, i.e. the stare point of the patient is changed between each shot but the camera is kept fixed. Between each shot, the apparent shape and position of all the retinal structures that do not exhibit isotropic reflectance (e.g. bright artefacts) change. This physical effect is exploited by our algorithm in order to extract the pixels belonging to the inner layers of the retina, hence obtaining a single artefacts-free image.

Respiratory motion artefacts in dynamic liver MRI: a comparison using gadoxetate disodium and gadobutrol

Energy Technology Data Exchange (ETDEWEB)

Luetkens, Julian A.; Kupczyk, Patrick A.; Doerner, Jonas; Willinek, Winfried A.; Schild, Hans H.; Kukuk, Guido M. [University of Bonn, Department of Radiology, Bonn (Germany); Fimmers, Rolf [University of Bonn, Department of Medical Biometry, Informatics, and Epidemiology, Bonn (Germany)

2015-11-15

Our aim was to retrospectively evaluate the occurrence of respiratory motion artefacts in patients undergoing dynamic liver magnetic resonance (MR) either with gadoxetate disodium or gadobutrol. Two hundred and thirty liver MR studies (115 with gadobutrol, 115 with gadoxetate disodium) were analysed. Respiratory motion artefacts on dynamic 3D T1-weighted MR images (pre-contrast, arterial, venous, and late-dynamic phase) were assessed using a five-point rating scale. Severe motion was defined as a score ≥ 4. Mean motion scores were compared with the Mann-Whitney-U-test. The chi-squared-test was used for dichotomous comparisons. Mean motion scores for gadoxetate disodium and gadobutrol showed no relevant differences for each phase of the dynamic contrast series (pre-contrast: 1.85 ± 0.70 vs. 1.88 ± 0.57, arterial: 1.85 ± 0.81 vs. 1.87 ± 0.74, venous: 1.82 ± 0.67 vs. 1.74 ± 0.64, late-dynamic: 1.75 ± 0.62 vs. 1.79 ± 0.63; p = 0.469, 0.557, 0.382 and 0.843, respectively). Severe motion artefacts had a similar incidence using gadoxetate disodium and gadobutrol (11/460 [2.4 %] vs. 7/460 [1.5 %]; p = 0.341). Gadoxetate disodium is associated with equivalent motion scores compared to gadobutrol in dynamic liver MRI. In addition, both contrast agents demonstrated a comparable and acceptable rate of severe respiratory motion artefacts. (orig.)

Reconstruction artefacts in magnetic induction tomography due to patient's movement during data acquisition

International Nuclear Information System (INIS)

Gürsoy, D; Scharfetter, H

2009-01-01

Magnetic induction tomography (MIT) attempts to obtain the distribution of passive electrical properties inside the body. Eddy currents are induced in the body using an array of transmitter coils and the magnetic fields of these currents are measured by receiver coils. In clinical usage, the relative position of the coils to the body can change during data acquisition because of the expected/unexpected movements of the patient. Especially in respiration monitoring these movements will inevitably cause artefacts in the reconstructed images. In this paper, this effect was investigated for both state and frequency differential variants of MIT. It was found that a slight shift of the body in the transverse plane causes spurious perturbations on the surface. In reconstructions, this artefact on the surface propagates towards the centre in an oscillatory manner. It was observed that the movement can corrupt all the valuable information in state differential MIT, while frequency differential MIT seems more robust against movement effects. A filtering strategy is offered in order to decrease the movement artefacts in the images. To this end, monitoring of the patient's movement during data acquisition is required

The source of prehistoric obsidian artefacts from the Polynesian outlier of Taumako in the Solomon Islands

Energy Technology Data Exchange (ETDEWEB)

Leach, Foss [Otago Univ., Dunedin (New Zealand). Dept. of Anthropology

1985-01-01

Six obsidian artefacts from the Polynesian outlier of Taumako in the Solomon Islands dating to between 500 and 1000 B.C. were analysed for trace elements by the PIXE-PIGME method. Four are shown to derive from Vanuatu, but the remaining two artefacts do not match any of the known 66 sources in the Pacific region. Continuing difficulties with the methodology of Pacific obsidian sourcing are discussed. 14 refs; 2 tables.

Research into tin and arsenical copper artefacts using nuclear analytical techniques

International Nuclear Information System (INIS)

Grant, M.R.

1995-01-01

This study includes the chemical analysis, sourcing and historical metallurgy of tin and arsenical copper artefacts discovered at Rooiberg and elsewhere in the Northern Transvaal and at Great Zimbabwe. A complete chemical analysis method for tin and cassiterite is presented, based on INAA (instrumental neutron activation analysis) and supplemented by PIXE or AAS for elements such as lead, bismuth and niobium. This is apparently the first study in which tin artefacts were analysed by INAA without chemical processing of the samples. INAA and PIXE returned the same results when a homogenized tin alloy block was analysed, but the structure and distribution of hardhead phases appear to produce an iron quantification problem in ancient tin. Ores and slags were analysed for light matrix elements by XRF or PIXE and INAA for the heavy trace metals. 108 refs., 24 figs., 130 tabs

Artefacts induced by coiled intracranial aneurysms on 3.0-Tesla versus 1.5-Tesla MR angiography—An in vivo and in vitro study

Energy Technology Data Exchange (ETDEWEB)

Schaafsma, Joanna D., E-mail: j.d.schaafsma@umcutrecht.nl [Department of Neurology, Rudolf Magnus Institute of Neuroscience, University Medical Centre, PO Box 85500, 3508 GA Utrecht (Netherlands); Velthuis, Birgitta K., E-mail: b.k.velthuis@umcutrecht.nl [Imaging Division, University Medical Centre, PO Box 85500, 3508 GA Utrecht (Netherlands); Vincken, Koen L., E-mail: koen@isi.uu.nl [Image Sciences Institute, University Medical Centre, PO Box 85500, 3508 GA Utrecht (Netherlands); Kort, Gerard A.P. de, E-mail: g.a.p.dekort@umcutrecht.nl [Imaging Division, University Medical Centre, PO Box 85500, 3508 GA Utrecht (Netherlands); Rinkel, Gabriel J.E., E-mail: g.j.e.rinkel@umcutrecht.nl [Department of Neurology, Rudolf Magnus Institute of Neuroscience, University Medical Centre, PO Box 85500, 3508 GA Utrecht (Netherlands); Bartels, Lambertus W., E-mail: w.bartels@umcutrecht.nl [Image Sciences Institute, University Medical Centre, PO Box 85500, 3508 GA Utrecht (Netherlands)

2014-05-15

Objective: To compare metal-induced artefacts from coiled intracranial aneurysms on 3.0-Tesla and 1.5-Tesla magnetic resonance angiography (MRA), since concerns persist on artefact enlargement at 3.0 Tesla. Materials and methods: We scanned 19 patients (mean age 53; 16 women) with 20 saccular aneurysms treated with coils only, at 1.5 and 3.0 Tesla according to standard clinical 3D TOF-MRA protocols containing a shorter echo-time but weaker read-out gradient at 3.0 Tesla in addition to intra-arterial digital subtraction angiography (IA-DSA). Per modality two neuro-radiologists assessed the occlusion status, measured residual flow, and indicated whether coil artefacts disturbed this assessment on MRA. We assessed relative risks for disturbance by coil artefacts, weighted kappa's for agreement on occlusion levels, and we compared remnant sizes. For artefact measurements, a coil model was created and scanned with the same protocols followed by 2D MR scans with variation of echo-time and read-out gradient strength. Results: Coil artefacts disturbed assessments less frequently at 3.0 Tesla than at 1.5 Tesla (RR: 0.3; 95%CI: 0.1–0.8). On 3.0-Tesla MRA, remnants were larger than on 1.5-Tesla MRA (difference: 0.7 mm; 95%CI: 0.3–1.1) and larger than on IA-DSA (difference: 1.0 mm; 95%CI: 0.6–1.5) with similar agreement on occlusion levels with IA-DSA for both field strengths (κ 0.53; 95%CI: 0.23–0.84 for 1.5-Tesla MRA and IA-DSA; κ 0.47; 95%CI: 0.19–0.76 for 3.0-Tesla MRA and IA-DSA). Coil model artefacts were smaller at 3.0 Tesla than at 1.5 Tesla. The echo-time influenced artefact size more than the read-out gradient. Conclusions: Artefacts were not larger, but smaller at 3.0 Tesla because a shorter echo-time at 3.0 Tesla negated artefact enlargement. Despite smaller artefacts and larger remnants at 3.0 Tesla, occlusion levels were similar for both field strengths.

Artefacts induced by coiled intracranial aneurysms on 3.0-Tesla versus 1.5-Tesla MR angiography—An in vivo and in vitro study

International Nuclear Information System (INIS)

Schaafsma, Joanna D.; Velthuis, Birgitta K.; Vincken, Koen L.; Kort, Gerard A.P. de; Rinkel, Gabriel J.E.; Bartels, Lambertus W.

2014-01-01

Objective: To compare metal-induced artefacts from coiled intracranial aneurysms on 3.0-Tesla and 1.5-Tesla magnetic resonance angiography (MRA), since concerns persist on artefact enlargement at 3.0 Tesla. Materials and methods: We scanned 19 patients (mean age 53; 16 women) with 20 saccular aneurysms treated with coils only, at 1.5 and 3.0 Tesla according to standard clinical 3D TOF-MRA protocols containing a shorter echo-time but weaker read-out gradient at 3.0 Tesla in addition to intra-arterial digital subtraction angiography (IA-DSA). Per modality two neuro-radiologists assessed the occlusion status, measured residual flow, and indicated whether coil artefacts disturbed this assessment on MRA. We assessed relative risks for disturbance by coil artefacts, weighted kappa's for agreement on occlusion levels, and we compared remnant sizes. For artefact measurements, a coil model was created and scanned with the same protocols followed by 2D MR scans with variation of echo-time and read-out gradient strength. Results: Coil artefacts disturbed assessments less frequently at 3.0 Tesla than at 1.5 Tesla (RR: 0.3; 95%CI: 0.1–0.8). On 3.0-Tesla MRA, remnants were larger than on 1.5-Tesla MRA (difference: 0.7 mm; 95%CI: 0.3–1.1) and larger than on IA-DSA (difference: 1.0 mm; 95%CI: 0.6–1.5) with similar agreement on occlusion levels with IA-DSA for both field strengths (κ 0.53; 95%CI: 0.23–0.84 for 1.5-Tesla MRA and IA-DSA; κ 0.47; 95%CI: 0.19–0.76 for 3.0-Tesla MRA and IA-DSA). Coil model artefacts were smaller at 3.0 Tesla than at 1.5 Tesla. The echo-time influenced artefact size more than the read-out gradient. Conclusions: Artefacts were not larger, but smaller at 3.0 Tesla because a shorter echo-time at 3.0 Tesla negated artefact enlargement. Despite smaller artefacts and larger remnants at 3.0 Tesla, occlusion levels were similar for both field strengths

Artefacts induced by coiled intracranial aneurysms on 3.0-Tesla versus 1.5-Tesla MR angiography--An in vivo and in vitro study.

Science.gov (United States)

Schaafsma, Joanna D; Velthuis, Birgitta K; Vincken, Koen L; de Kort, Gerard A P; Rinkel, Gabriel J E; Bartels, Lambertus W

2014-05-01

To compare metal-induced artefacts from coiled intracranial aneurysms on 3.0-Tesla and 1.5-Tesla magnetic resonance angiography (MRA), since concerns persist on artefact enlargement at 3.0Tesla. We scanned 19 patients (mean age 53; 16 women) with 20 saccular aneurysms treated with coils only, at 1.5 and 3.0Tesla according to standard clinical 3D TOF-MRA protocols containing a shorter echo-time but weaker read-out gradient at 3.0Tesla in addition to intra-arterial digital subtraction angiography (IA-DSA). Per modality two neuro-radiologists assessed the occlusion status, measured residual flow, and indicated whether coil artefacts disturbed this assessment on MRA. We assessed relative risks for disturbance by coil artefacts, weighted kappa's for agreement on occlusion levels, and we compared remnant sizes. For artefact measurements, a coil model was created and scanned with the same protocols followed by 2D MR scans with variation of echo-time and read-out gradient strength. Coil artefacts disturbed assessments less frequently at 3.0Tesla than at 1.5Tesla (RR: 0.3; 95%CI: 0.1-0.8). On 3.0-Tesla MRA, remnants were larger than on 1.5-Tesla MRA (difference: 0.7mm; 95%CI: 0.3-1.1) and larger than on IA-DSA (difference: 1.0mm; 95%CI: 0.6-1.5) with similar agreement on occlusion levels with IA-DSA for both field strengths (κ 0.53; 95%CI: 0.23-0.84 for 1.5-Tesla MRA and IA-DSA; κ 0.47; 95%CI: 0.19-0.76 for 3.0-Tesla MRA and IA-DSA). Coil model artefacts were smaller at 3.0Tesla than at 1.5Tesla. The echo-time influenced artefact size more than the read-out gradient. Artefacts were not larger, but smaller at 3.0Tesla because a shorter echo-time at 3.0Tesla negated artefact enlargement. Despite smaller artefacts and larger remnants at 3.0Tesla, occlusion levels were similar for both field strengths. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Computed Tomography Imaging of a Hip Prosthesis Using Iterative Model-Based Reconstruction and Orthopaedic Metal Artefact Reduction: A Quantitative Analysis.

Science.gov (United States)

Wellenberg, Ruud H H; Boomsma, Martijn F; van Osch, Jochen A C; Vlassenbroek, Alain; Milles, Julien; Edens, Mireille A; Streekstra, Geert J; Slump, Cornelis H; Maas, Mario

To quantify the combined use of iterative model-based reconstruction (IMR) and orthopaedic metal artefact reduction (O-MAR) in reducing metal artefacts and improving image quality in a total hip arthroplasty phantom. Scans acquired at several dose levels and kVps were reconstructed with filtered back-projection (FBP), iterative reconstruction (iDose) and IMR, with and without O-MAR. Computed tomography (CT) numbers, noise levels, signal-to-noise-ratios and contrast-to-noise-ratios were analysed. Iterative model-based reconstruction results in overall improved image quality compared to iDose and FBP (P < 0.001). Orthopaedic metal artefact reduction is most effective in reducing severe metal artefacts improving CT number accuracy by 50%, 60%, and 63% (P < 0.05) and reducing noise by 1%, 62%, and 85% (P < 0.001) whereas improving signal-to-noise-ratios by 27%, 47%, and 46% (P < 0.001) and contrast-to-noise-ratios by 16%, 25%, and 19% (P < 0.001) with FBP, iDose, and IMR, respectively. The combined use of IMR and O-MAR strongly improves overall image quality and strongly reduces metal artefacts in the CT imaging of a total hip arthroplasty phantom.

Evidence of metallic plating on archaeological artefacts by voltammetry of microparticles

Czech Academy of Sciences Publication Activity Database

Ottenwelter, Estelle; Costa, V.

2015-01-01

Roč. 57, č. 3 (2015), s. 497-504 ISSN 0003-813X Institutional support: RVO:67985912 Keywords : metallic plating * voltammetry of microparticles * non-invasive analysis * medieval period * archaeological artefacts Subject RIV: AC - Archeology, Anthropology, Ethnology Impact factor: 1.364, year: 2015

A simple solution for reducing artefacts due to conductive and dielectric effects in clinical magnetic resonance imaging at 3 T

International Nuclear Information System (INIS)

Sreenivas, M.; Lowry, M.; Gibbs, P.; Pickles, M.; Turnbull, L.W.

2007-01-01

The quality of imaging obtained at high magnetic field strengths can be degraded by various artefacts due to conductive and dielectric effects, which leads to loss of signal. Various methods have been described and used to improve the quality of the image affected by such artefacts. In this article, we describe the construction and use of a simple solution that can be used to diminish artefacts due to conductive and dielectric effects in clinical imaging at 3 T field strength and thereby improve the diagnostic quality of the images obtained

A simple solution for reducing artefacts due to conductive and dielectric effects in clinical magnetic resonance imaging at 3 T

Energy Technology Data Exchange (ETDEWEB)

Sreenivas, M. [Department of Radiology (Yorkshire Deanery-East), Hull Royal Infirmary, Anlaby Road, Hull HU3 2JZ (United Kingdom)]. E-mail: aprilsreenivas@hotmail.com; Lowry, M. [Centre for Magnetic Resonance Investigations, University of Hull, Hull Royal Infirmary, Anlaby Road, 1PR, Hull HU3 2JZ (United Kingdom); Gibbs, P. [Centre for Magnetic Resonance Investigations, University of Hull, Hull Royal Infirmary, Anlaby Road, 1PR, Hull HU3 2JZ (United Kingdom); Pickles, M. [Centre for Magnetic Resonance Investigations, University of Hull, Hull Royal Infirmary, Anlaby Road, 1PR, Hull HU3 2JZ (United Kingdom); Turnbull, L.W. [Centre for Magnetic Resonance Investigations, University of Hull, Hull Royal Infirmary, Anlaby Road, 1PR, Hull HU3 2JZ (United Kingdom)

2007-04-15

The quality of imaging obtained at high magnetic field strengths can be degraded by various artefacts due to conductive and dielectric effects, which leads to loss of signal. Various methods have been described and used to improve the quality of the image affected by such artefacts. In this article, we describe the construction and use of a simple solution that can be used to diminish artefacts due to conductive and dielectric effects in clinical imaging at 3 T field strength and thereby improve the diagnostic quality of the images obtained.

Suppression of high-density artefacts in x-ray CT images using temporal digital subtraction with application to cryotherapy

Energy Technology Data Exchange (ETDEWEB)

Baissalov, R.; Sandison, G.A.; Rewcastle, J.C. [Department of Medical Physics, Tom Baker Cancer Center, Calgary, Canada, T2N 4N2 2 Department of Physics and Astronomy, University of Calgary, Calgary T2N 2N4 (Canada); Donnelly, B.J. [Department of Surgery, Tom Baker Cancer Center, Calgary, Canada, T2N 4N2 4 Department of Surgery, Foothills Hospital, Calgary T2N 2T7 (Canada); Saliken, J.C. [Department of Surgery, Tom Baker Cancer Center, Calgary T2N 4N2 (Canada); Department of Diagnostic Imaging, Foothills Hospital, Calgary T2N 2T7 (Canada); McKinnon, J.G. [Department of Surgery, Foothills Hospital, Calgary T2N 2T7 (Canada); Muldrew, K. [Department of Surgery, Faculty of Medicine, University of Calgary, Calgary T2N 2T7 (Canada)

2000-05-01

Image guidance in cryotherapy is usually performed using ultrasound. Although not currently in routine clinical use, x-ray CT imaging is an alternative means of guidance that can display the full 3D structure of the iceball, including frozen and unfrozen regions. However, the quality of x-ray CT images is compromised by the presence of high-density streak artefacts. To suppress these artefacts we applied temporal digital subtraction (TDS). This TDS method has the added advantage of improving the grey-scale contrast between frozen and unfrozen tissue in the CT images. Two sets of CT images were taken of a phantom material, cryoprobes and a urethral warmer (UW) before and during the cryoprobe freeze cycle. The high-density artefacts persisted in both image sets. TDS was performed on these two image sets using the corresponding mask image of unfrozen material and the same geometrical configuration of the cryoprobes and the UW. The resultant difference image had a significantly reduced artefact content. Thus TDS can be used to significantly suppress or eliminate high-density CT streak artefacts without reducing the metallic content of the cryoprobes. In vivo study needs to be conducted to establish the utility of this TDS procedure for CT assisted prostate or liver cryotherapy. Applying TDS in x-ray CT guided cryotherapy will facilitate estimation of the number and location of all frozen and unfrozen regions, potentially making cryotherapy safer and less operator dependent. (author)

Suppression of high-density artefacts in x-ray CT images using temporal digital subtraction with application to cryotherapy

International Nuclear Information System (INIS)

Baissalov, R.; Sandison, G.A.; Rewcastle, J.C.; Donnelly, B.J.; Saliken, J.C.; McKinnon, J.G.; Muldrew, K.

2000-01-01

Image guidance in cryotherapy is usually performed using ultrasound. Although not currently in routine clinical use, x-ray CT imaging is an alternative means of guidance that can display the full 3D structure of the iceball, including frozen and unfrozen regions. However, the quality of x-ray CT images is compromised by the presence of high-density streak artefacts. To suppress these artefacts we applied temporal digital subtraction (TDS). This TDS method has the added advantage of improving the grey-scale contrast between frozen and unfrozen tissue in the CT images. Two sets of CT images were taken of a phantom material, cryoprobes and a urethral warmer (UW) before and during the cryoprobe freeze cycle. The high-density artefacts persisted in both image sets. TDS was performed on these two image sets using the corresponding mask image of unfrozen material and the same geometrical configuration of the cryoprobes and the UW. The resultant difference image had a significantly reduced artefact content. Thus TDS can be used to significantly suppress or eliminate high-density CT streak artefacts without reducing the metallic content of the cryoprobes. In vivo study needs to be conducted to establish the utility of this TDS procedure for CT assisted prostate or liver cryotherapy. Applying TDS in x-ray CT guided cryotherapy will facilitate estimation of the number and location of all frozen and unfrozen regions, potentially making cryotherapy safer and less operator dependent. (author)

Clinical learning environments: place, artefacts and rhythm.

Science.gov (United States)

Sheehan, Dale; Jowsey, Tanisha; Parwaiz, Mariam; Birch, Mark; Seaton, Philippa; Shaw, Susan; Duggan, Alison; Wilkinson, Tim

2017-10-01

Health care practitioners learn through experience in clinical environments in which supervision is a key component, but how that learning occurs outside the supervision relationship remains largely unknown. This study explores the environmental factors that inform and support workplace learning within a clinical environment. An observational study drawing on ethnographic methods was undertaken in a general medicine ward. Observers paid attention to interactions among staff members that involved potential teaching and learning moments that occurred and were visible in the course of routine work. General purpose thematic analysis of field notes was undertaken. A total of 376 observations were undertaken and documented. The findings suggest that place (location of interaction), rhythm (regularity of activities occurring in the ward) and artefacts (objects and equipment) were strong influences on the interactions and exchanges that occurred. Each of these themes had inherent tensions that could promote or inhibit engagement and therefore learning opportunities. Although many learning opportunities were available, not all were taken up or recognised by the participants. We describe and make explicit how the natural environment of a medical ward and flow of work through patient care contribute to the learning architecture, and how this creates or inhibits opportunities for learning. Awareness of learning opportunities was often tacit and not explicit for either supervisor or learner. We identify strategies through which tensions inherent within space, artefacts and the rhythms of work can be resolved and learning opportunities maximised. © 2017 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

The use of radiation in the study of cultural heritage artefacts

International Nuclear Information System (INIS)

Creagh, Dudley; Otieno-Alego, Vincent; Treasure, Alana; Kubik, Maria; Hallam, David

2017-01-01

Patrons of art galleries and museums, tourists visiting historic buildings, and sightseers viewing archaeological sites are generally unaware of the extent to which science and technology has contributed to the value of what they see. Many countries rely on cultural tourism to generate national wealth. The use of radiation of many kinds to assist in the conservation/restoration of cultural heritage artefacts is described in this paper. In particular, the paper will describe studies of the pigments used in historic Australian Indigenous art, the degradation of manuscripts written using iron-gall inks, the protection of statues against corrosion and the selection of lubricants for use in old machinery. - Highlights: • We describe a diverse range of techniques used to study cultural heritage artefacts. • IR X-ray and particle beam techniques were used to study: • The structure and composition of Australian Indigenous bark paintings. • The effects of iron-gall inks on parchment. • The results of corrosion and corrosion protection in machinery and vehicles.

Lab-based x-ray tomography of a cochlear implant using energy discriminating detectors for metal artefact reduction

Science.gov (United States)

Yokhana, Viona S. K.; Arhatari, Benedicta D.; Gureyev, Timur E.; Abbey, Brian

2018-01-01

X-ray computed tomography (XCT) is an important clinical diagnostic tool which is also used in a range of biological imaging applications in research. The increasing prevalence of metallic implants in medical and dental radiography and tomography has driven the demand for new approaches to solving the issue of metal artefacts in XCT. Metal artefacts occur when a highly absorbing material is imaged which is in boundary contact with one or more weakly absorbing components, such as soft-tissue. The resulting `streaking' in the reconstructed images creates significant challenges for X-ray analysis due to the non-linear dependence on the absorption properties of the sample. In this paper we introduce a new approach to removing metal artefacts which exploits the capabilities of the recently available, photon-counting PiXirad detector. Our approach works for standard lab-based polychromatic X-ray tubes and does not rely on any postprocessing of the data. The method is demonstrated using both simulated data from a test phantom and experimental data collected from a cochlear implant. The results show that by combining the individual images, which are simultaneously generated for each different energy threshold, artefact -free segmentation of the implant from the surrounding biological tissue is achieved.

Evaluation of a prototype correction algorithm to reduce metal artefacts in flat detector computed tomography of scaphoid fixation screws.

Science.gov (United States)

Filli, Lukas; Marcon, Magda; Scholz, Bernhard; Calcagni, Maurizio; Finkenstädt, Tim; Andreisek, Gustav; Guggenberger, Roman

2014-12-01

The aim of this study was to evaluate a prototype correction algorithm to reduce metal artefacts in flat detector computed tomography (FDCT) of scaphoid fixation screws. FDCT has gained interest in imaging small anatomic structures of the appendicular skeleton. Angiographic C-arm systems with flat detectors allow fluoroscopy and FDCT imaging in a one-stop procedure emphasizing their role as an ideal intraoperative imaging tool. However, FDCT imaging can be significantly impaired by artefacts induced by fixation screws. Following ethical board approval, commercially available scaphoid fixation screws were inserted into six cadaveric specimens in order to fix artificially induced scaphoid fractures. FDCT images corrected with the algorithm were compared to uncorrected images both quantitatively and qualitatively by two independent radiologists in terms of artefacts, screw contour, fracture line visibility, bone visibility, and soft tissue definition. Normal distribution of variables was evaluated using the Kolmogorov-Smirnov test. In case of normal distribution, quantitative variables were compared using paired Student's t tests. The Wilcoxon signed-rank test was used for quantitative variables without normal distribution and all qualitative variables. A p value of < 0.05 was considered to indicate statistically significant differences. Metal artefacts were significantly reduced by the correction algorithm (p < 0.001), and the fracture line was more clearly defined (p < 0.01). The inter-observer reliability was "almost perfect" (intra-class correlation coefficient 0.85, p < 0.001). The prototype correction algorithm in FDCT for metal artefacts induced by scaphoid fixation screws may facilitate intra- and postoperative follow-up imaging. Flat detector computed tomography (FDCT) is a helpful imaging tool for scaphoid fixation. The correction algorithm significantly reduces artefacts in FDCT induced by scaphoid fixation screws. This may facilitate intra

Are osseous artefacts a window to perishable material culture? Implications of an unusually complex bone tool from the Late Pleistocene of East Timor.

Science.gov (United States)

O'Connor, S; Robertson, G; Aplin, K P

2014-02-01

We report the discovery of an unusually complex and regionally unique bone artefact in a Late Pleistocene archaeological assemblage (c. 35 ka [thousands of years ago]) from the site of Matja Kuru 2 on the island of Timor, in Wallacea. The artefact is interpreted as the broken butt of a formerly hafted projectile point, and it preserves evidence of a complex hafting mechanism including insertion into a shaped or split shaft, a complex pattern of binding including lateral stabilization of the cordage within a bilateral series of notches, and the application of mastic at several stages in the hafting process. The artefact provides the earliest direct evidence for the use of this combination of hafting technologies in the wider region of Southeast Asia, Wallacea, Melanesia and Australasia, and is morphologically unparallelled in deposits of any age. By contrast, it bears a close morphological resemblance to certain bone artefacts from the Middle Stone Age of Africa and South Asia. Examination of ethnographic projectile technology from the region of Melanesia and Australasia shows that all of the technological elements observed in the Matja Kuru 2 artefact were in use historically in the region, including the unusual feature of bilateral notching to stabilize a hafted point. This artefact challenges the notion that complex bone-working and hafting technologies were a relatively late innovation in this part of the world. Moreover, its regional uniqueness encourages us to abandon the perception of bone artefacts as a discrete class of material culture, and to adopt a new interpretative framework in which they are treated as manifestations of a more general class of artefacts that more typically were produced on perishable raw materials including wood. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

Planning Uncertainty: Creating an Artefact Density Index for North Yorkshire, England

Directory of Open Access Journals (Sweden)

Nick Boldrini

2007-04-01

Full Text Available Portable antiquities (sometimes known as small finds or chance finds are often recorded within most Historic Environment Records to a spurious level of precision. For example, finds located only within a parish, or general area, are often mapped within GIS systems to exact points. Similarly, finds known only to the nearest kilometre square are usually mapped in the bottom left-hand corner of the square in GIS. While such mappings can be taken into account to some extent when trying to assess the archaeological potential of an area, the degree to which the records may give distorted views of the archaeological potential of an area may not be fully appreciated. This may mean that the full archaeological impacts of development may not be taken into account during development control decision making. This article looks at an alternative method for mapping such finds in order to produce an Artefact Density Index for areas, which more usefully reflects the pattern of activities across the landscape. The Artefact Density Index (ADI was divided to reflect broad archaeological periods (e.g. Roman, medieval etc., as well as broad artefact types (e.g. weapons, tools etc.. The ADI was based on combining weighted values for finds types, with the weight reflecting the precision of the location of the finds (i.e. finds recorded only at parish level will be given less weight than those recorded more precisely. An ADI was developed for a sub-area of the North Yorkshire County Council HER area, and also incorporated data from the Portable Antiquities scheme as a case study for the project.

Implications of Artefacts Reduction in the Planning CT Originating from Implanted Fiducial Markers

International Nuclear Information System (INIS)

Kassim, Iskandar; Joosten, Hans; Barnhoorn, Jaco C.; Heijmen, Ben J.M.; Dirkx, Maarten L.P.

2011-01-01

The efficacy of metal artefact reduction (MAR) software to suppress artefacts in reconstructed computed tomography (CT) images originating from small metal objects, like tumor markers and surgical clips, was evaluated. In addition, possible implications of using digital reconstructed radiographs (DRRs), based on the MAR CT images, for setup verification were analyzed. A phantom and 15 patients with different tumor sites and implanted markers were imaged with a multislice CT scanner. The raw image data was reconstructed both with the clinically used filtered-backprojection (FBP) and with the MAR software. Using the MAR software, improvements in image quality were often observed in CT slices with markers or clips. Especially when several markers were located near to each other, fewer streak artefacts were observed than with the FBP algorithm. In addition, the shape and size of markers could be identified more accurately, reducing the contoured marker volumes by a factor of 2. For the phantom study, the CT numbers measured near to the markers corresponded more closely to the expected values. However, the MAR images were slightly more smoothed compared with the images reconstructed with FBP. For 8 prostate cancer patients in this study, the interobserver variation in 3D marker definition was similar (<0.4 mm) when using DRRs based on either FBP or MAR CT scans. Automatic marker matches also showed a similar success rate. However, differences in automatic match results up to 1 mm, caused by differences in the marker definition, were observed, which turned out to be (borderline) statistically significant (p = 0.06) for 2 patients. In conclusion, the MAR software might improve image quality by suppressing metal artefacts, probably allowing for a more reliable delineation of structures. When implanted markers or clips are used for setup verification, the accuracy may slightly be improved as well, which is relevant when using very tight clinical target volume (CTV) to

Angiographic and artefact-free computed tomography imaging of experimental aneurysms embolised with hydrogel filaments

Energy Technology Data Exchange (ETDEWEB)

McCoy, Mark R. [Paracelsus Medical University, Department of Radiology and Magnetic Resonance Tomography, Christian Doppler Clinic, Salzburg (Austria); Cruise, Gregory M. [MicroVention Terumo, Aliso Viejo, CA (United States); Killer, Monika [Paracelsus Medical University, Department of Neurology/Neuroscience Institute, Christian Doppler Clinic, Salzburg (Austria)

2010-04-15

We compared experimental rabbit carotid bifurcation aneurysms embolised with platinum coils or hydrogel filaments by using digital subtraction angiography (DSA) and computed tomography angiography (CTA). Embolisation was performed using platinum coils (n = 2), hydrogel filaments loaded with iodine (n = 3) and hydrogel filaments loaded with barium sulphate (n = 3). In one case, a stent was deployed in the parent vessel to determine the effect of hydrogel filaments on stent visualisation. DSA evaluations occurred immediately post-treatment. CTA evaluations occurred at 0-13 weeks post-treatment. The DSA and CTA images were evaluated for the lack of artefacts and the visibilities of the embolic mass, individual coils and residual flow in the aneurysm sac and neck. The DSA results were largely concordant among the three groups. The embolic masses were readily evident with some individual coils being distinguished. In the aneurysms embolised with hydrogel filaments, visualisation of the individual coils, residual flow and stent with minor or no artefacts was possible using CTA. On the other hand, the beam hardening artefacts precluded analysis of aneurysms embolised with platinum coils. CTA-compatible embolic devices could have wide applications in diverse locations throughout the vasculature, particularly in combination with stents or stent grafts. (orig.)

Risk Identification in a Smart Monitoring System Used to Preserve Artefacts Based on Textile Materials

Science.gov (United States)

Diaconescu, V. D.; Scripcariu, L.; Mătăsaru, P. D.; Diaconescu, M. R.; Ignat, C. A.

2018-06-01

Exhibited textile-materials-based artefacts can be affected by the environmental conditions. A smart monitoring system that commands an adaptive automatic environment control system is proposed for indoor exhibition spaces containing various textile artefacts. All exhibited objects are monitored by many multi-sensor nodes containing temperature, relative humidity and light sensors. Data collected periodically from the entire sensor network is stored in a database and statistically processed in order to identify and classify the environment risk. Risk consequences are analyzed depending on the risk class and the smart system commands different control measures in order to stabilize the indoor environment conditions to the recommended values and prevent material degradation.

Transverse grooved artefacts from southwestern Asia and northern Eurasia: Common traits and the reconstruction of function

Directory of Open Access Journals (Sweden)

Irina Usacheva

2016-10-01

Full Text Available Transverse grooved artefacts (TGA appeared as a new cultural element in Mesolithic-Proto-Neolithic sites in southwestern Asia. We know of similar artefacts from northern Africa. Hundreds of TGA have also been found in northern Eurasia. Some common traits were found in specimens from far apart territories, such as the non-abrasive heat-resistant nature of the raw materials, specificity of fragmentation without any signs of physical impact, the standard size of the grooves, association with a specific type of landscape, the similar economic level of the societies with which the items are associated, and use-wear marks in the grooves. Based on these regularities we can speak of a single main function for these artefacts which support the earlier reconstruction of R.L. and R.S. Solecki, suggesting that grooved stones were used for straightening cane and reed shafts under heating. Other evidence and traces that have been identified on the surface of TGA outside the groove could be associated with a variety of additional functions.

42 CFR 409.49 - Excluded services.

Science.gov (United States)

2010-10-01

... HOSPITAL INSURANCE BENEFITS Home Health Services Under Hospital Insurance § 409.49 Excluded services. (a... individual's dialysis, are excluded from coverage under the Medicare home health benefit. (f) Prosthetic... 42 Public Health 2 2010-10-01 2010-10-01 false Excluded services. 409.49 Section 409.49 Public...

Evaluation of a prototype correction algorithm to reduce metal artefacts in flat detector computed tomography of scaphoid fixation screws

Energy Technology Data Exchange (ETDEWEB)

Filli, Lukas; Finkenstaedt, Tim; Andreisek, Gustav; Guggenberger, Roman [University Hospital of Zurich, Department of Diagnostic and Interventional Radiology, Zurich (Switzerland); Marcon, Magda [University Hospital of Zurich, Department of Diagnostic and Interventional Radiology, Zurich (Switzerland); University of Udine, Institute of Diagnostic Radiology, Department of Medical and Biological Sciences, Udine (Italy); Scholz, Bernhard [Imaging and Therapy Division, Siemens AG, Healthcare Sector, Forchheim (Germany); Calcagni, Maurizio [University Hospital of Zurich, Division of Plastic Surgery and Hand Surgery, Zurich (Switzerland)

2014-12-15

The aim of this study was to evaluate a prototype correction algorithm to reduce metal artefacts in flat detector computed tomography (FDCT) of scaphoid fixation screws. FDCT has gained interest in imaging small anatomic structures of the appendicular skeleton. Angiographic C-arm systems with flat detectors allow fluoroscopy and FDCT imaging in a one-stop procedure emphasizing their role as an ideal intraoperative imaging tool. However, FDCT imaging can be significantly impaired by artefacts induced by fixation screws. Following ethical board approval, commercially available scaphoid fixation screws were inserted into six cadaveric specimens in order to fix artificially induced scaphoid fractures. FDCT images corrected with the algorithm were compared to uncorrected images both quantitatively and qualitatively by two independent radiologists in terms of artefacts, screw contour, fracture line visibility, bone visibility, and soft tissue definition. Normal distribution of variables was evaluated using the Kolmogorov-Smirnov test. In case of normal distribution, quantitative variables were compared using paired Student's t tests. The Wilcoxon signed-rank test was used for quantitative variables without normal distribution and all qualitative variables. A p value of < 0.05 was considered to indicate statistically significant differences. Metal artefacts were significantly reduced by the correction algorithm (p < 0.001), and the fracture line was more clearly defined (p < 0.01). The inter-observer reliability was ''almost perfect'' (intra-class correlation coefficient 0.85, p < 0.001). The prototype correction algorithm in FDCT for metal artefacts induced by scaphoid fixation screws may facilitate intra- and postoperative follow-up imaging. (orig.)

Evaluation of a prototype correction algorithm to reduce metal artefacts in flat detector computed tomography of scaphoid fixation screws

International Nuclear Information System (INIS)

Filli, Lukas; Finkenstaedt, Tim; Andreisek, Gustav; Guggenberger, Roman; Marcon, Magda; Scholz, Bernhard; Calcagni, Maurizio

2014-01-01

The aim of this study was to evaluate a prototype correction algorithm to reduce metal artefacts in flat detector computed tomography (FDCT) of scaphoid fixation screws. FDCT has gained interest in imaging small anatomic structures of the appendicular skeleton. Angiographic C-arm systems with flat detectors allow fluoroscopy and FDCT imaging in a one-stop procedure emphasizing their role as an ideal intraoperative imaging tool. However, FDCT imaging can be significantly impaired by artefacts induced by fixation screws. Following ethical board approval, commercially available scaphoid fixation screws were inserted into six cadaveric specimens in order to fix artificially induced scaphoid fractures. FDCT images corrected with the algorithm were compared to uncorrected images both quantitatively and qualitatively by two independent radiologists in terms of artefacts, screw contour, fracture line visibility, bone visibility, and soft tissue definition. Normal distribution of variables was evaluated using the Kolmogorov-Smirnov test. In case of normal distribution, quantitative variables were compared using paired Student's t tests. The Wilcoxon signed-rank test was used for quantitative variables without normal distribution and all qualitative variables. A p value of < 0.05 was considered to indicate statistically significant differences. Metal artefacts were significantly reduced by the correction algorithm (p < 0.001), and the fracture line was more clearly defined (p < 0.01). The inter-observer reliability was ''almost perfect'' (intra-class correlation coefficient 0.85, p < 0.001). The prototype correction algorithm in FDCT for metal artefacts induced by scaphoid fixation screws may facilitate intra- and postoperative follow-up imaging. (orig.)

Hydrogen equilibrium pressure measurements in the Li-N-H system by static manometric method

International Nuclear Information System (INIS)

Ananda, N.S.; Jat, R.A.; Sawant, S.G.; Parida, S.C.; Singh, Z.; Venugopal, V.

2010-01-01

Light weight hydrogen storage materials are very promising in terms of their high gravimetric hydrogen storage capacity and low cost. One such reported system is the Li-N-H system with a theoretical hydrogen capacity of 11.5 wt% according to the following equilibrium reactions; (1) Li 3 N+H 2 → Li 2 NH + LiH and (2) Li 2 NH+H 2 → LiNH 2 + LiH. The enthalpy of reaction (1) is -165 kJ/mole of H 2 whereas that of reaction (2) is -45 kJ/mole of H 2 . Hence, the second reaction is of utmost importance for low temperature release of hydrogen with a capacity of 6.5 wt%. The equilibrium hydrogen pressures of the above two reactions have been reported by pressure-composition isotherm studies at a pressure range of 3-15 atm., in which the mid-point of the sloping plateau of P-C isotherm is considered as the equilibrium pressure. This method may not yield the true equilibrium pressure. Hence, in this study, we have carried out measurements of equilibrium pressure using a static manometric method where we have considered reaction (2) only

24 CFR 3280.7 - Excluded structures.

Science.gov (United States)

2010-04-01

... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Excluded structures. 3280.7 Section... DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS General § 3280.7 Excluded structures. Certain structures may be excluded from these Standards as modular homes under 24 CFR 3282.12. [52 FR 4581, Feb. 12...

PET/CT Atlas on Quality Control and Image Artefacts

International Nuclear Information System (INIS)

2014-01-01

Combined positron emission tomography (PET)/computed tomography (CT) imaging has become a routine procedure in diagnostic radiology and nuclear medicine. The clinical review of both PET and PET/CT images requires a thorough understanding of the basics of image formation as well as an appreciation of variations of inter-patient and intra-patient image appearance. Such variations may be caused by variations in tracer accumulation and metabolism, and, perhaps more importantly, by image artefacts related to methodological pitfalls of the two modalities. This atlas on quality control (QC) and PET/CT artefacts provides guidance on typical image distortions in clinical PET/CT usage scenarios. A number of cases are presented to provide nuclear medicine and radiology professionals with an assortment of examples of possible image distortions and errors in order to support the correct interpretation of images. About 70 typical PET and PET/CT cases, comprised of image sets and cases, have been collected in this book, and all have been catalogued and have explanations as to the causes of and solutions to each individual image problem. This atlas is intended to be used as a guide on how to take proper QC measures, on performing situation and problem analysis, and on problem prevention. This book will be especially useful to medical physicists, physicians, technologists and service engineers in the clinical field

Energy consumption and stocks of energy-converting artefacts

International Nuclear Information System (INIS)

Bladh, Mats

2012-01-01

The development of total energy consumption is important in a world with limited resources. It is the result of two basic tendencies working in opposite directions: growth in number and in use (such as more cars and driving more) and improvements in energy efficiency (such as more fuel-efficient engines). Since the 1970s growth of energy consumption has slowed down in Sweden. This means that increasing supply has been counteracted by measures improving overall energy efficiency to a larger degree than before. How can long-term development in energy consumption be analysed? This paper proposes a focus on stocks of energy-converting artefacts as a tool for such analyses. In order to show the fruitfulness of this approach, historical data on cars, dwellings and lamps in Sweden are used. Results from the cases in this paper show considerable gains of efficiency in fuel consumption in private cars and heating efficiency in multi-dwelling houses. Demographic factors are important for the outcome. The approach seems to promise a way to analyse energy efficiency that captures both promoting and counteracting factors at both the micro and macro level. - Highlights: ► Growth of energy consumption slowed down in the 1970s, a break in the long-run trend. ► Balance between growth and efficiency factors changes over time and areas of use. ► Savings in heating were not taken back, while those for cars were. ► Focus on stocks of artefacts is a promising tool for analyses. ► Incremental changes within existing stocks can be as big as radical changes.

Evaluation of the impact of dental artefacts on intensity-modulated radiotherapy planning for the head and neck

International Nuclear Information System (INIS)

Webster, Gareth J.; Rowbottom, Carl G.; Mackay, Ranald I.

2009-01-01

Background and purpose: High density materials create severe artefacts in the computed tomography (CT) scans used for radiotherapy dose calculations. Increased use of intensity-modulated radiotherapy (IMRT) to treat oropharyngeal cancers raises concerns over the accuracy of the resulting dose calculation. This work quantifies their impact and evaluates a simple corrective technique. Materials and methods: Fifteen oropharyngeal patients with severe artefacts were retrospectively planned with IMRT using two different CT/density look-up tables. Each plan was recalculated using a corrected CT dataset to evaluate the dose distribution delivered to the patient. Plan quality in the absence of dental artefacts was similarly assessed. A range of dosimetric and radiobiological parameters were compared pre- and post-correction. Results: Plans using a standard CT/density look-up table (density ≤1.8 g/cm 3 ) revealed inconsistent inter-patient errors, mostly within clinical acceptance, although potentially significantly reducing target coverage for individual patients. Using an extended CT/density look-up table (density ≤10.0 g/cm 3 ) greatly reduced the errors for 13/15 patients. In 2/15 patients with residual errors the CTV extended into the severely affected region and could be corrected by applying a simple manual correction. Conclusions: Use of an extended CT/density look-up table together with a simple manual bulk density correction reduces the impact of dental artefacts on head and neck IMRT planning to acceptable levels.

Evaluation of efficacy of metal artefact reduction technique using contrast media in Computed Tomography

Science.gov (United States)

Yusob, Diana; Zukhi, Jihan; Aziz Tajuddin, Abd; Zainon, Rafidah

2017-05-01

The aim of this study was to evaluate the efficacy of metal artefact reduction using contrasts media in Computed Tomography (CT) imaging. A water-based abdomen phantom of diameter 32 cm (adult body size) was fabricated using polymethyl methacrylate (PMMA) material. Three different contrast agents (iodine, barium and gadolinium) were filled in small PMMA tubes and placed inside a water-based PMMA adult abdomen phantom. The orthopedic metal screw was placed in each small PMMA tube separately. These two types of orthopedic metal screw (stainless steel and titanium alloy) were scanned separately. The orthopedic metal crews were scanned with single-energy CT at 120 kV and dual-energy CT at fast kV-switching between 80 kV and 140 kV. The scan modes were set automatically using the current modulation care4Dose setting and the scans were set at different pitch and slice thickness. The use of the contrast media technique on orthopedic metal screws were optimised by using pitch = 0.60 mm, and slice thickness = 5.0 mm. The use contrast media can reduce the metal streaking artefacts on CT image, enhance the CT images surrounding the implants, and it has potential use in improving diagnostic performance in patients with severe metallic artefacts. These results are valuable for imaging protocol optimisation in clinical applications.

The origin of emeralds embedded in archaeological artefacts in Slovenia

Directory of Open Access Journals (Sweden)

Albina Kržič

2013-06-01

Full Text Available Roman gold jewellery, which was excavated in Ptuj (Poetovio and consists of a necklace, earrings and a braceletwith embedded emeralds, is part of the Slovenian archaeological artefacts collections. Crystallographic characteristics,inclusions, luminous phenomena and geological characteristics were determined in order to establish theorigin of the emeralds. Chemical composition of the emeralds was determined non-destructively using the methodsof proton-induced X-rays and gamma rays (PIXE/PIGE. The results were compared with reference emeraldsfrom Habachtal in Austria and with green beryls from the Ural Mts. Literature data for emeralds from Egypt andmodern-day Afghanistan area were used to interpret the results. Specifically, these sites were known for emeraldsbeing mined for jewellery in Roman times. It was assumed that emeralds from archaeological artefacts originatedfrom Habachtal in Austria, given that this site was the nearest to the place where found. But the emeralds fromthe necklace and earrings in fact came from Egyptian deposits. The origin of emeralds from the bracelet could nothave been determined absolutely reliably due to the lack of comparative materials; they may originate from a site inmodern-day Afghanistan or from Egypt, but certainly not from the same site as the previously mentioned emeraldsin the necklace and earrings.

Primary flow meter for calibrating a sniffer test leak artefact by a pressure rise method

Science.gov (United States)

Arai, Kenta; Yoshida, Hajime

2014-10-01

Sniffer tests are used to locate leaks in equipment during operation. The sensitivity of a sniffer leak detector must be calibrated against a known gas flow to atmospheric pressure generated by a sniffer test leak artefact. We have developed a primary flow meter for calibrating gas flows to atmospheric pressure through the leak artefact. The flow meter is based on a pressure rise method and two chambers are used to measure the pressure rise with small uncertainty even at atmospheric pressure. The calibration range of the flow rate is 5 × 10-7 Pa m3 s-1 to 7 × 10-4 Pa m3 s-1 to atmospheric pressure at 23.0 °C with a minimum uncertainty of 1.4% (k = 2), as well as 4 × 10-8 Pa m3 s-1 to 5 × 10-4 Pa m3 s-1 to a vacuum at 23.0 °C. The long term stability of the flow meter was determined as 0.41% by repeated measurements of the conductance of the leak artefact. In case of the flow rate into a vacuum, the flow meter was successfully linked to the international reference value of CCM.P-K12 by a lab-internal comparison.

Persuasiveness, Personalization & Productive Workplace Practices with IT-Knowledge Artefacts

DEFF Research Database (Denmark)

Fischer, Louise Harder; Pries-Heje, Lene

2016-01-01

work. We see a possible way forward for improving workplace practices with IT-knowledge artefact based applications, by combining new insight of how different personality traits prefer different knowledge sharing processes with new insight on personalizing persuasive technology. We explore new research......The workplace is getting increasingly globalized, virtualized and networked. At the same time, work itself has become discrete, autonomous and complex. In a fast changing world, the individual knowledge worker and his interactions becomes the new locus of value creation. Management promote...

A flint artefact (Accession No. DONMG 2016.7.1 from Lindholme, South Yorkshire

Directory of Open Access Journals (Sweden)

Alan Saville

2016-09-01

Full Text Available One of the last papers which Alan was working on when he died was a short note on a flint artefact from the surface of a gravel scrape at Lindholme in South Yorkshire. This was found during fieldwork by Robert Friend, a postgraduate student in Geography at the University of Edinburgh, working on the limits of the last glaciation in the Vale of York (Friend 2011. The results of this have been published elsewhere (Bateman et al. 2015; Friend et al. 2016, but the context of the artefact is ambivalent and Alan’s appendix on the flint was judged too archaeological and site specific for inclusion in either paper. It is a find, however, worth placing on record as one of a number of scattered surface finds of Upper Palaeolithic affinity from the region (compare with Garton et al. 2016; Grassam & Weston 2015; Harding et al. 2014.

The effect of magnetisation transfer contrast on cerebrospinal fluid on motion artefacts on fluid-attenuated inversion-recovery images

International Nuclear Information System (INIS)

Aprile, I.; Principi, M.; Ottaviano, P.; Scapeccia, M.

2003-01-01

We assessed possible advantages of the use of fluid-attenuated inversion-recovery (FLAIR) sequences with magnetisation-transfer contrast (MTC) over conventional FLAIR images. We carried out cranial MRI at 1 tesla on 50 patients with both sequences. In nine patients with multiple sclerosis (MS) we performed a quantitative comparison of the two sequences, looking at the contrast-to-noise ratio between lesions and normal white matter and counting the number of lesions shown using each method. A qualitative comparison on all patients consisted of the analysis of the appearance of the normal parenchyma, of any lesions, and of artefacts, with particular reference to cerebrospinal fluid (CSF) motion artefacts. The quantitative analysis showed no meaningful difference between the two sequences. The cerebral parenchyma and lesions appeared substantially the same with both techniques. With FLAIR MTC there was a clear, and consistent reduction in CSF motion artefacts. FLAIR MTC sequences can usefully be used in place of the conventional sequence at 1 tesla. (orig.)

Reducing the effects of metal artefact using high keV monoenergetic reconstruction of dual energy CT (DECT) in hip replacements

Energy Technology Data Exchange (ETDEWEB)

Lewis, Mark [Norfolk and Norwich University Hospital, Norwich (United Kingdom); Norwich Radiology Academy, Norwich (United Kingdom); Reid, Karen [Norfolk and Norwich University Hospital, Norwich (United Kingdom); Toms, Andoni P. [Norfolk and Norwich University Hospital and University of East Anglia, Norwich (United Kingdom)

2013-02-15

The aim of this study was to determine whether high keV monoenergetic reconstruction of dual energy computed tomography (DECT) could be used to overcome the effects of beam hardening artefact that arise from preferential deflection of low energy photons. Two phantoms were used: a Charnley total hip replacement set in gelatine and a Catphan 500. DECT datasets were acquired at 100, 200 and 400 mA (Siemens Definition Flash, 100 and 140 kVp) and reconstructed using a standard combined algorithm (1:1) and then as monoenergetic reconstructions at 10 keV intervals from 40 to 190 keV. Semi-automated segmentation with threshold inpainting was used to obtain the attenuation values and standard deviation (SD) of the streak artefact. High contrast line pair resolution and background noise were assessed using the Catphan 500. Streak artefact is progressively reduced with increasing keV monoenergetic reconstructions. Reconstruction of a 400 mA acquisition at 150 keV results in reduction in the volume of streak artefact from 65 cm{sup 3} to 17 cm{sup 3} (74 %). There was a decrease in the contrast to noise ratio (CNR) at higher tube voltages, with the peak CNR seen at 70-80 keV. High contrast spatial resolution was maintained at high keV values. Monoenergetic reconstruction of dual energy CT at increasing theoretical kilovoltages reduces the streak artefact produced by beam hardening from orthopaedic prostheses, accompanied by a modest increase in heterogeneity of background image attenuation, and decrease in contrast to noise ratio, but no deterioration in high contrast line pair resolution. (orig.)

Reducing beam hardening effects and metal artefacts using Medipix3RX: With applications from biomaterial science

CERN Document Server

Rajendran, K; de Ruiter, N J A; Chernoglazov, A I; Panta, R K; Butler, A P H; Butler, P H; Bell, S T; Anderson, N G; Woodfield, T B F; Tredinnick, S J; Healy, J L; Bateman, C J; Aamir, R; Doesburg, R M N; Renaud, P F; Gieseg, S P; Smithies, D J; Mohr, J L; Mandalika, V B H; Opie, A M T; Cook, N J; Ronaldson, J P; Nik, S J; Atharifard, A; Clyne, M; Bones, P J; Bartneck, C; Grasset, R; Schleich, N; Billinghurst, M

2014-01-01

This paper discusses methods for reducing beam hardening effects using spectral data for biomaterial applications. A small-animal spectral scanner operating in the diagnostic energy range was used. We investigate the use of photon-processing features of the Medipix3RX ASIC in reducing beam hardening and associated artefacts. A fully operational charge summing mode was used during the imaging routine. We present spectral data collected for metal alloy samples, its analysis using algebraic 3D reconstruction software and volume visualisation using a custom volume rendering software. Narrow high energy acquisition using the photon-processing detector revealed substantial reduction in beam hardening effects and metal artefacts.

Colloids or artefacts? A TVO/SKB cooperation project in Olkiluoto, Finland

International Nuclear Information System (INIS)

Laaksoharju, M.; Vuorinen, U.; Snellman, M.; Helenius, J.; Allard, B.; Pettersson, C.; Hinkkanen, H.

1993-12-01

TVO (Teollisuuden Voima Oy, Finland) initiated a co-operative task with SKB (Swedish Nuclear Fuel and Waste Management Co.) to critically evaluate colloid sampling methods at the test site in Olkiluoto, SW Finland. Three different colloid sampling methods were compared when sampling borehole OL-KR1 at 613-618 m depth. One possible way to make a conservative in-situ colloid estimation is to omit the contribution from calcite precipitation which is considered to be the main artefact. When this is made the inorganic colloid content (size 1-1000 nm) in Olkiluoto is 184 ±177 ppb consisting of clay minerals, silica, pyrite, goethite and magnesium oxide; the concentration of organic substances are around 100 ppb. The in-situ colloid concentration seems to be low which is in good agreement with experiences from years of sampling in similar environment and depths. The exercise shows the many difficulties encountered when sampling colloids. Small error in the planning, pump rate selection, a lack of precautionary measures, artefact sensitivity of the method etc have a tendency to affect significantly the results on the measured ppb colliod level

Multi-secular corrosion behaviour of low carbon steel in anoxic soils: Characterisation of corrosion system on archaeological artefacts

International Nuclear Information System (INIS)

Saheb, M.; Neff, D.; Dillmann, P.; Foy, E.; Saheb, M.; Dillmann, P.; Matthiesen, H.; Bellot-Gurlet, L.

2009-01-01

In the context of the prediction of materials behaviour used in the nuclear waste storage, the understanding of iron corrosion mechanisms in anoxic environment is of great importance. Information can be obtained using complementary analytical tools. Interactions between burial soil and archaeological artefacts are studied by performing on site soil measurements. Moreover, archaeological artefacts are studied on transverse sections using a combination of microbeam techniques. The specific interest of this project lies in the study of ferrous thick corrosion layers formed in anoxic environment. (authors)

Spatial analysis of "crazy quilts", a class of potentially random aesthetic artefacts.

Directory of Open Access Journals (Sweden)

Gesche Westphal-Fitch

Full Text Available Human artefacts in general are highly structured and often display ordering principles such as translational, reflectional or rotational symmetry. In contrast, human artefacts that are intended to appear random and non symmetrical are very rare. Furthermore, many studies show that humans find it extremely difficult to recognize or reproduce truly random patterns or sequences. Here, we attempt to model two-dimensional decorative spatial patterns produced by humans that show no obvious order. "Crazy quilts" represent a historically important style of quilt making that became popular in the 1870s, and lasted about 50 years. Crazy quilts are unusual because unlike most human artefacts, they are specifically intended to appear haphazard and unstructured. We evaluate the degree to which this intention was achieved by using statistical techniques of spatial point pattern analysis to compare crazy quilts with regular quilts from the same region and era and to evaluate the fit of various random distributions to these two quilt classes. We found that the two quilt categories exhibit fundamentally different spatial characteristics: The patch areas of crazy quilts derive from a continuous random distribution, while area distributions of regular quilts consist of Gaussian mixtures. These Gaussian mixtures derive from regular pattern motifs that are repeated and we suggest that such a mixture is a distinctive signature of human-made visual patterns. In contrast, the distribution found in crazy quilts is shared with many other naturally occurring spatial patterns. Centroids of patches in the two quilt classes are spaced differently and in general, crazy quilts but not regular quilts are well-fitted by a random Strauss process. These results indicate that, within the constraints of the quilt format, Victorian quilters indeed achieved their goal of generating random structures.

Spatial analysis of "crazy quilts", a class of potentially random aesthetic artefacts.

Science.gov (United States)

Westphal-Fitch, Gesche; Fitch, W Tecumseh

2013-01-01

Human artefacts in general are highly structured and often display ordering principles such as translational, reflectional or rotational symmetry. In contrast, human artefacts that are intended to appear random and non symmetrical are very rare. Furthermore, many studies show that humans find it extremely difficult to recognize or reproduce truly random patterns or sequences. Here, we attempt to model two-dimensional decorative spatial patterns produced by humans that show no obvious order. "Crazy quilts" represent a historically important style of quilt making that became popular in the 1870s, and lasted about 50 years. Crazy quilts are unusual because unlike most human artefacts, they are specifically intended to appear haphazard and unstructured. We evaluate the degree to which this intention was achieved by using statistical techniques of spatial point pattern analysis to compare crazy quilts with regular quilts from the same region and era and to evaluate the fit of various random distributions to these two quilt classes. We found that the two quilt categories exhibit fundamentally different spatial characteristics: The patch areas of crazy quilts derive from a continuous random distribution, while area distributions of regular quilts consist of Gaussian mixtures. These Gaussian mixtures derive from regular pattern motifs that are repeated and we suggest that such a mixture is a distinctive signature of human-made visual patterns. In contrast, the distribution found in crazy quilts is shared with many other naturally occurring spatial patterns. Centroids of patches in the two quilt classes are spaced differently and in general, crazy quilts but not regular quilts are well-fitted by a random Strauss process. These results indicate that, within the constraints of the quilt format, Victorian quilters indeed achieved their goal of generating random structures.

The neuropathic oesophagus. A radiographic and manometric study on the evolution of megaoesophagus in dogs with developing axonal neuropathy

International Nuclear Information System (INIS)

Satchell, P.M.

1990-01-01

Dogs given the neurotoxin acrylamide develop peripheral neuropathy and megaoesophagus. Sequential radiographic and manometric studies on the oesophagus demonstrated that the initial abnormalities consisted of a progressive decrease in the proportion of swallows that initiated peristalsis and a gradual increase in oesophageal calibre. Regurgitation, peristaltic failure and oesophageal dilatation all appeared within three days. The eating behaviour and gait abnormalities quickly resolved on stopping the neurotoxin, but the oesophagus remained dilated for longer. Previous studies have suggested that the abnormalities present in dogs which are developing a distal axonal neuropathy or in some dogs with idiopathic megaoesophagus may be limited to the proprioceptive elements of the oesophageal innervation. The present study suggests that the progressive inefficiency in the transmission of swallows and changes in oesophageal calibre in dogs with evolving megaoesophagus may be a consequence of damage to these proprioceptive elements

Algorithms that eliminate the effects of calibration artefact and trial-imposed offsets of Masimo oximeter in BOOST-NZ trial.

Science.gov (United States)

Zahari, Marina; Lee, Dominic Savio; Darlow, Brian Alexander

2016-10-01

The displayed readings of Masimo pulse oximeters used in the Benefits Of Oxygen Saturation Targeting (BOOST) II and related trials in very preterm babies were influenced by trial-imposed offsets and an artefact in the calibration software. A study was undertaken to implement new algorithms that eliminate the effects of offsets and artefact. In the BOOST-New Zealand trial, oxygen saturations were averaged and stored every 10 s up to 36 weeks' post-menstrual age. Two-hundred and fifty-seven of 340 babies enrolled in the trial had at least two weeks of stored data. Oxygen saturation distribution patterns corresponding with a +3 % or -3 % offset in the 85-95 % range were identified together with that due to the calibration artefact. Algorithms involving linear and quadratic interpolations were developed, implemented on each baby of the dataset and validated using the data of a UK preterm baby, as recorded from Masimo oximeters with the original software and a non-offset Siemens oximeter. Saturation distributions obtained were compared for both groups. There were a flat region at saturations 85-87 % and a peak at 96 % from the lower saturation target oximeters, and at 93-95 and 84 % respectively from the higher saturation target oximeters. The algorithms lowered the peaks and redistributed the accumulated frequencies to the flat regions and artefact at 87-90 %. The resulting distributions were very close to those obtained from the Siemens oximeter. The artefact and offsets of the Masimo oximeter's software had been addressed to determine the true saturation readings through the use of novel algorithms. The implementation would enable New Zealand data be included in the meta-analysis of BOOST II trials, and be used in neonatal oxygen studies.

Endosonographic and manometric assessment of the anal sphincters after ileal pouch-anal anastomosis

International Nuclear Information System (INIS)

Sudol-Szopinska, I.; Jakubowski, W.; Ciesielski, A.; Bielecki, K.; Baczuk, L.; Tarnowski, W.

2003-01-01

Background. The aim of this study was to compare endosonography and manometry of the anal sphincters in patients after ileal pouch-anal anastomosis (IPAA). Patients and methods. Ten patients aged between 23 and 50 years with IPAA performed for ulcerative colitis were examined with anal endosonography (AES) and manometry. Results. AES visualised abnormal image of the internal anal sphincter (IAS) in 9 patients (90%). Defects of the external anal sphincter (EAS) and puborectalis muscle (PR) were shown in 4 patients (40%). In 5 patients (50%) correlation between endosonographic and manometric assessment for the all analysed muscles: IAS, EAS and PR was found. In 4 cases (40%) both methods correlated with the evaluation of the EAS only and in 1 patient (10%) no correlation was found. Correlation between both methods for the IAS was found in half of the patients (50%) while in the evaluation of the EAS and PR dynamic activity, it was found in 9 cases (90%). Conclusions. Anal endosonography and manometry allow us to assess the morphology as well as the function of the anal sphincters in patients with IPAA. The methods mentioned above show high correlation in the assessment of the EAS function (9 cases; 90%) whereas in the case of IAS, manometry frequently (5 patients; 50%) does not confirm endosonografically detected defects. (author)

Pixeanalysis of some artefacts from the first Bulgarian capital pliska in 9th-11th centuries

International Nuclear Information System (INIS)

Georgiev, Pavel; Ilieva, Galina; Penev, Ilia; Tzekova, Galina; Pantelica, Dan; Pantelica, Ana; Ionescu, Paul; Gugiu, Marius; Fluerasu, Daniela; Calinescu, Ionut C.; Costache, Cristian

2014-01-01

Proton Induced X-ray Emission (PIXE) technique has been applied to determine major, minor and trace elements in 20 metallic and glass artefacts discovered in 2012 from the archaeological site Pliska, the old capital of Bulgaria in 9th-11th centuries. PIXE analysis was performed using a 3 MeV proton beam in vacuum at the 9 MeV Van de Graaff Tandem accelerator of IFIN-HH in Bucharest-Magurele, Romania. The GUPIX (Guelph PIXE) programme was employed to determine the quantities of around 30 elements (Z ≥ 14) in the investigated samples. The obtained results were compared with literature data for the medieval epoch in Bulgaria. Key words: PIXE, elemental content, artefacts, metal, glass, Pliska, Bulgaria

Lesion concordance, image quality and artefacts in PET/CT. Results of a multicenter study

International Nuclear Information System (INIS)

Stergar, H.; Bockisch, A.; Krause, B.J.; Eschmann, S.M.; Juergens, K.U.; Kuehl, H.; Pfannenberg, A.C.; Stollfuss, J.; Weckesser, M.

2010-01-01

This study had three major objectives: (1.) to record the number of concordant (both in PET and CT) pathological lesions in different body regions/organs, (2.) to evaluate the image quality and (3.) to determine both, the quantity and the quality of artefacts in whole body FDG PET/CT scans. Routine whole body scans of 353 patients referred to FDG-PET/CT exams at 4 university hospitals were employed. All potentially malignant lesions in 13 different body regions/organs were classified as either concordant or suspicious in FDG-PET or CT only. In the latter case the diagnostic relevance of this disparity was judged. The image quality in PET and CT was rated as a whole and separately in 5 different body regions. Furthermore we investigated the frequency and site of artefacts caused by metal implants and oral or intravenous contrast media as well as the subjective co-registration quality (in 4 body regions) and the diagnostic impact of such artefacts or misalignment. In addition, the readers rated the diagnostic gain of adding the information from the other tomographic method. In total 1941 lesions (5.5 per patient) were identified, 1094 (56%) out of which were concordant. 602 (71%) out of the 847 remaining lesions were detected only with CT, 245 (29%) were only PET-positive. As expected, CT particularly depicted the majority of lesions in the lungs and abdominal organs. However, the diagnostic relevance was greater with PET-only positive lesions. Most of the PET/CT scans were performed with full diagnostic CT including administration of oral and intravenous contast media (> 80%). The image quality in PET and CT was rated excellent. Artefacts occurred in more than 60% of the scans and were mainly due to (dental) metal implants and contrast agent. Nevertheless there was almost no impact on diagnostic confidence if reading of the non attenuation corrected PET was included. The co-registration quality in general was also rated as excellent. Misalignment mostly occurred due

The development of equipment for the technical assessment of respiratory motion induced artefacts in MRI

International Nuclear Information System (INIS)

Jackson, P.C.; Davies, S.C.; Zananiri, F.V.; Follett, D.H.; Halliwell, M.; Wells, P.N.T.; Bean, J.P.

1993-01-01

A device and technique to study the effects of respiratory motion on the quality of magnetic resonance images is proposed. The construction of the device enables a variety of test objects to be mounted and used in the evaluation of imaging parameters that may be affected by motion. The equipment is constructed of cast acrylic and the movement is actuated and controlled pneumatically thus ensuring that there are no interactions with the magnetic field and radiofrequency detection system to cause further image artefacts. Separate studies have been performed, using ultrasound, to assess the degree and rate of movement of organs owing to respiration in order to derive the motion parameters for the apparatus. Preliminary results indicate that the technique produces motion induced artefacts simulating those which are the result of the effects of respiration. (author)

Metal artefact suppression at 3 T MRI: comparison of MAVRIC-SL with conventional fast spin echo sequences in patients with Hip joint arthroplasty

International Nuclear Information System (INIS)

Kretzschmar, Martin; Nardo, Lorenzo; Han, Misung M.; Heilmeier, Ursula; Sam, Craig; Joseph, Gabby B.; Krug, Roland; Link, Thomas M.; Koch, Kevin M.

2015-01-01

The aim of our study was to evaluate the clinical feasibility and diagnostic value of a new MRI metal artefact reduction pulse sequence called MAVRIC-SL in a 3 T MRI environment. Two MAVRIC-SL sequences obtained in 61 patients with symptomatic total hip replacement were compared with standard FSE-STIR sequences optimized for imaging around metal. Artefact size was measured on the slice of greatest extent. Image quality, fat saturation, image distortion, visibility of anatomical structures, and detectability of joint abnormalities were visually assessed and graded on qualitative scales. Differences between MAVRIC-SL and FSE sequences were tested with the Wilcoxon signed-rank test. MAVRIC-SL sequences at 3 T showed significantly smaller metal artefacts compared to FSE-STIR sequences (p < 0.0001). The general image quality of MAVRIC-SL sequences was reduced with regard to spatial resolution, noise and contrast (p = 0.001), and fat saturation (p < 0.0001). The reduction of artefact size and image distortion significantly improved visualization of joint anatomy (p < 0.0001) and diagnostic confidence regarding implant-associated abnormalities (p = 0.0075 to <0.0001). Although the image quality of MAVRIC-SL sequences is limited at 3 T, its clinical application is feasible and provides important additional diagnostic information for the workup of patients with symptomatic hip replacement through substantially reduced metal artefacts. (orig.)

Metal artefact suppression at 3 T MRI: comparison of MAVRIC-SL with conventional fast spin echo sequences in patients with Hip joint arthroplasty

Energy Technology Data Exchange (ETDEWEB)

Kretzschmar, Martin; Nardo, Lorenzo; Han, Misung M.; Heilmeier, Ursula; Sam, Craig; Joseph, Gabby B.; Krug, Roland; Link, Thomas M. [University of California San Francisco, Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, San Francisco, CA (United States); Koch, Kevin M. [Medical Collage of Wisconsin, Departments of Biophysics and Radiology, Milwaukee, WI (United States)

2015-08-15

The aim of our study was to evaluate the clinical feasibility and diagnostic value of a new MRI metal artefact reduction pulse sequence called MAVRIC-SL in a 3 T MRI environment. Two MAVRIC-SL sequences obtained in 61 patients with symptomatic total hip replacement were compared with standard FSE-STIR sequences optimized for imaging around metal. Artefact size was measured on the slice of greatest extent. Image quality, fat saturation, image distortion, visibility of anatomical structures, and detectability of joint abnormalities were visually assessed and graded on qualitative scales. Differences between MAVRIC-SL and FSE sequences were tested with the Wilcoxon signed-rank test. MAVRIC-SL sequences at 3 T showed significantly smaller metal artefacts compared to FSE-STIR sequences (p < 0.0001). The general image quality of MAVRIC-SL sequences was reduced with regard to spatial resolution, noise and contrast (p = 0.001), and fat saturation (p < 0.0001). The reduction of artefact size and image distortion significantly improved visualization of joint anatomy (p < 0.0001) and diagnostic confidence regarding implant-associated abnormalities (p = 0.0075 to <0.0001). Although the image quality of MAVRIC-SL sequences is limited at 3 T, its clinical application is feasible and provides important additional diagnostic information for the workup of patients with symptomatic hip replacement through substantially reduced metal artefacts. (orig.)

The characterisation of Melanesian obsidian sources and artefacts using the proton induced gamma-ray emission (PIGME) technique

International Nuclear Information System (INIS)

Bird, J.R.; Ambrose, W.R.; Russell, L.H.; Scott, M.D.

1981-09-01

Proton induced gamma-ray emission (PIGME) has been used to determine F, Na and Al concentrations in obsidian from known locations in Melanesia and to relate artefacts from this region to such sources. The PIGME technique is a fast, non-destructive, and accurate method for determining these three elements with essentially no special sample preparation. The measuring technique is described and results are listed for sources, chiefly in the Papua New Guinea region. Their classification is discussed in terms of groups which are distinguishable by the PIGME method. Over 700 artefact results are listed; these show the occurrence of an additional group that is not geographically identified

Sci—Fri PM: Dosimetry—01: Radiation-induced refraction artefacts in the optical CT readout of polymer gel dosimeters

International Nuclear Information System (INIS)

Campbell, Warren G; Jirasek, Andrew; Wells, Derek M

2014-01-01

Polymer gel dosimeters (PGDs) are a desirable tool for the verification of advanced radiotherapy treatments. Fully 3D, deformable, and tissue-equivalent, the PGD polymerizes wherever it absorbs dose. To measure the dose absorbed by a PGD, optical computed tomography (CT) can be used to evaluate, in full 3D, the opacity distribution that coincides with polymerization. In addition to an increase in opacity with dose, an increase in refractive index (RI) is also known to occur in irradiated polymer gels. The increase in RI is slight and was previously assumed insignificant. This work reveals the effects that radiation-induced RI changes can have on the optical CT readout of PGDs. A fan-beam optical CT scanner was used to image a cylindrical PGD irradiated by a pair of 3×3 cm 2 , 6 MV photon beams in an orthogonal arrangement. Investigative scans were performed to evaluate refraction errors occurring: i) within the plane, and ii) out of the plane of the fan-beam. In-plane refraction was shown to cause distinct streaking artefacts along dose gradients (i.e. RI gradients) due to higher intensity rays being refracted into more opaque regions. Out-of-plane refraction was shown to produce severe, widespread artefacts due to rays missing the detector array. An iterative Savitzky-Golay filtering technique was developed to reduce both types of artefacts by specifically targeting structured errors in sinogram space. Results introduce a new category of imaging artefacts to be aware of when using optical CT for PGD readout

Introduction. Leave no stone unturned: Perspectives on ground stone artefact research

OpenAIRE

Danny Rosenberg; Yorke Rowan; Tatjana Gluhak

2016-01-01

Ground stone tools served in many physical and social contexts through millennia, reflecting a wide variety of functions. Although ground stone tool studies were neglected for much of early archaeology, the last few decades witnessed a notable international uptick in the way archaeologists confront this multifaceted topic. Today, with the advance of archaeology as a discipline, research into ground stone artefacts is moving into a new phase that integrates high resolution documentation with n...

Spatial Analysis of “Crazy Quilts”, a Class of Potentially Random Aesthetic Artefacts

Science.gov (United States)

Westphal-Fitch, Gesche; Fitch, W. Tecumseh

2013-01-01

Human artefacts in general are highly structured and often display ordering principles such as translational, reflectional or rotational symmetry. In contrast, human artefacts that are intended to appear random and non symmetrical are very rare. Furthermore, many studies show that humans find it extremely difficult to recognize or reproduce truly random patterns or sequences. Here, we attempt to model two-dimensional decorative spatial patterns produced by humans that show no obvious order. “Crazy quilts” represent a historically important style of quilt making that became popular in the 1870s, and lasted about 50 years. Crazy quilts are unusual because unlike most human artefacts, they are specifically intended to appear haphazard and unstructured. We evaluate the degree to which this intention was achieved by using statistical techniques of spatial point pattern analysis to compare crazy quilts with regular quilts from the same region and era and to evaluate the fit of various random distributions to these two quilt classes. We found that the two quilt categories exhibit fundamentally different spatial characteristics: The patch areas of crazy quilts derive from a continuous random distribution, while area distributions of regular quilts consist of Gaussian mixtures. These Gaussian mixtures derive from regular pattern motifs that are repeated and we suggest that such a mixture is a distinctive signature of human-made visual patterns. In contrast, the distribution found in crazy quilts is shared with many other naturally occurring spatial patterns. Centroids of patches in the two quilt classes are spaced differently and in general, crazy quilts but not regular quilts are well-fitted by a random Strauss process. These results indicate that, within the constraints of the quilt format, Victorian quilters indeed achieved their goal of generating random structures. PMID:24066095

The fourth dimension of tool use: temporally enduring artefacts aid primates learning to use tools.

Science.gov (United States)

Fragaszy, D M; Biro, D; Eshchar, Y; Humle, T; Izar, P; Resende, B; Visalberghi, E

2013-11-19

All investigated cases of habitual tool use in wild chimpanzees and capuchin monkeys include youngsters encountering durable artefacts, most often in a supportive social context. We propose that enduring artefacts associated with tool use, such as previously used tools, partly processed food items and residual material from previous activity, aid non-human primates to learn to use tools, and to develop expertise in their use, thus contributing to traditional technologies in non-humans. Therefore, social contributions to tool use can be considered as situated in the three dimensions of Euclidean space, and in the fourth dimension of time. This notion expands the contribution of social context to learning a skill beyond the immediate presence of a model nearby. We provide examples supporting this hypothesis from wild bearded capuchin monkeys and chimpanzees, and suggest avenues for future research.

From Governing through Data to Governmentality through Data: Artefacts, Strategies and the Digital Turn

Science.gov (United States)

Souto-Otero, Manuel; Beneito-Montagut, Roser

2016-01-01

The article argues that current discussions about governance through data in education can be fruitfully extended through: (1) the establishment of connections with wider debates about the role of commensuration processes and governmentality in the recreation of education systems; (2) greater emphasis on the "artefacts" through which…

Magnetic resonance imaging acquisition techniques intended to decrease movement artefact in paediatric brain imaging: a systematic review

International Nuclear Information System (INIS)

Woodfield, Julie; Kealey, Susan

2015-01-01

Attaining paediatric brain images of diagnostic quality can be difficult because of young age or neurological impairment. The use of anaesthesia to reduce movement in MRI increases clinical risk and cost, while CT, though faster, exposes children to potentially harmful ionising radiation. MRI acquisition techniques that aim to decrease movement artefact may allow diagnostic paediatric brain imaging without sedation or anaesthesia. We conducted a systematic review to establish the evidence base for ultra-fast sequences and sequences using oversampling of k-space in paediatric brain MR imaging. Techniques were assessed for imaging time, occurrence of movement artefact, the need for sedation, and either image quality or diagnostic accuracy. We identified 24 relevant studies. We found that ultra-fast techniques had shorter imaging acquisition times compared to standard MRI. Techniques using oversampling of k-space required equal or longer imaging times than standard MRI. Both ultra-fast sequences and those using oversampling of k-space reduced movement artefact compared with standard MRI in unsedated children. Assessment of overall diagnostic accuracy was difficult because of the heterogeneous patient populations, imaging indications, and reporting methods of the studies. In children with shunt-treated hydrocephalus there is evidence that ultra-fast MRI is sufficient for the assessment of ventricular size. (orig.)

Magnetic resonance imaging acquisition techniques intended to decrease movement artefact in paediatric brain imaging: a systematic review

Energy Technology Data Exchange (ETDEWEB)

Woodfield, Julie [University of Edinburgh, Child Life and Health, Edinburgh (United Kingdom); Kealey, Susan [Western General Hospital, Department of Neuroradiology, Edinburgh (United Kingdom)

2015-08-15

Attaining paediatric brain images of diagnostic quality can be difficult because of young age or neurological impairment. The use of anaesthesia to reduce movement in MRI increases clinical risk and cost, while CT, though faster, exposes children to potentially harmful ionising radiation. MRI acquisition techniques that aim to decrease movement artefact may allow diagnostic paediatric brain imaging without sedation or anaesthesia. We conducted a systematic review to establish the evidence base for ultra-fast sequences and sequences using oversampling of k-space in paediatric brain MR imaging. Techniques were assessed for imaging time, occurrence of movement artefact, the need for sedation, and either image quality or diagnostic accuracy. We identified 24 relevant studies. We found that ultra-fast techniques had shorter imaging acquisition times compared to standard MRI. Techniques using oversampling of k-space required equal or longer imaging times than standard MRI. Both ultra-fast sequences and those using oversampling of k-space reduced movement artefact compared with standard MRI in unsedated children. Assessment of overall diagnostic accuracy was difficult because of the heterogeneous patient populations, imaging indications, and reporting methods of the studies. In children with shunt-treated hydrocephalus there is evidence that ultra-fast MRI is sufficient for the assessment of ventricular size. (orig.)

Persistent Artefacts in an Online Classroom: The Value of a Dynamic Learning Archive

Science.gov (United States)

Berry, Stuart C.

2016-01-01

This paper summarizes a multi-year research project that examines the use and value of visible and persistent artefacts within an online learning environment. This study is framed within elements of a business management theory. Changes to an online learning environment are documented as well as an examination of the impact of these changes on the…

The Mediation of Teaching and Learning Processes through "Identity Artefacts." A Vygotskian Perspective

Science.gov (United States)

Subero, David; Llopart, Mariona; Siqués, Carina; Esteban-Guitart, Moises

2018-01-01

The aim of this paper is to address the teaching and learning processes in schools from a Vygotskian perspective based on the notion of "identity artefacts" (IAs) which, for our purposes, consist of documents created by the learners about themselves, in which they try to capture all the things that make sense and are meaningful to them…

SU-E-J-158: Audiovisual Biofeedback Reduces Image Artefacts in 4DCT: A Digital Phantom Study

Energy Technology Data Exchange (ETDEWEB)

Pollock, S; Kipritidis, J; Lee, D; Keall, P [University of Sydney, Sydney (Australia); Bernatowicz, K [Paul Scherrer Institute, Psi, Aargau (Switzerland)

2015-06-15

Purpose: Irregular breathing motion has a deleterious impact on 4DCT image quality. The breathing guidance system: audiovisual biofeedback (AVB) is designed to improve breathing regularity, however, its impact on 4DCT image quality has yet to be quantified. The purpose of this study was to quantify the impact of AVB on thoracic 4DCT image quality by utilizing the digital eXtended Cardiac Torso (XCAT) phantom driven by lung tumor motion patterns. Methods: 2D tumor motion obtained from 4 lung cancer patients under two breathing conditions (i) without breathing guidance (free breathing), and (ii) with guidance (AVB). There were two breathing sessions, yielding 8 tumor motion traces. This tumor motion was synchronized with the XCAT phantom to simulate 4DCT acquisitions under two acquisition modes: (1) cine mode, and (2) prospective respiratory-gated mode. Motion regularity was quantified by the root mean square error (RMSE) of displacement. The number of artefacts was visually assessed for each 4DCT and summed up for each breathing condition. Inter-session anatomic reproducibility was quantified by the mean absolute difference (MAD) between the Session 1 4DCT and Session 2 4DCT. Results: AVB improved tumor motion regularity by 30%. In cine mode, the number of artefacts was reduced from 61 in free breathing to 40 with AVB, in addition to AVB reducing the MAD by 34%. In gated mode, the number of artefacts was reduced from 63 in free breathing to 51 with AVB, in addition to AVB reducing the MAD by 23%. Conclusion: This was the first study to compare the impact of breathing guidance on 4DCT image quality compared to free breathing, with AVB reducing the amount of artefacts present in 4DCT images in addition to improving inter-session anatomic reproducibility. Results thus far suggest that breathing guidance interventions could have implications for improving radiotherapy treatment planning and interfraction reproducibility.

SU-E-J-158: Audiovisual Biofeedback Reduces Image Artefacts in 4DCT: A Digital Phantom Study

International Nuclear Information System (INIS)

Pollock, S; Kipritidis, J; Lee, D; Keall, P; Bernatowicz, K

2015-01-01

Purpose: Irregular breathing motion has a deleterious impact on 4DCT image quality. The breathing guidance system: audiovisual biofeedback (AVB) is designed to improve breathing regularity, however, its impact on 4DCT image quality has yet to be quantified. The purpose of this study was to quantify the impact of AVB on thoracic 4DCT image quality by utilizing the digital eXtended Cardiac Torso (XCAT) phantom driven by lung tumor motion patterns. Methods: 2D tumor motion obtained from 4 lung cancer patients under two breathing conditions (i) without breathing guidance (free breathing), and (ii) with guidance (AVB). There were two breathing sessions, yielding 8 tumor motion traces. This tumor motion was synchronized with the XCAT phantom to simulate 4DCT acquisitions under two acquisition modes: (1) cine mode, and (2) prospective respiratory-gated mode. Motion regularity was quantified by the root mean square error (RMSE) of displacement. The number of artefacts was visually assessed for each 4DCT and summed up for each breathing condition. Inter-session anatomic reproducibility was quantified by the mean absolute difference (MAD) between the Session 1 4DCT and Session 2 4DCT. Results: AVB improved tumor motion regularity by 30%. In cine mode, the number of artefacts was reduced from 61 in free breathing to 40 with AVB, in addition to AVB reducing the MAD by 34%. In gated mode, the number of artefacts was reduced from 63 in free breathing to 51 with AVB, in addition to AVB reducing the MAD by 23%. Conclusion: This was the first study to compare the impact of breathing guidance on 4DCT image quality compared to free breathing, with AVB reducing the amount of artefacts present in 4DCT images in addition to improving inter-session anatomic reproducibility. Results thus far suggest that breathing guidance interventions could have implications for improving radiotherapy treatment planning and interfraction reproducibility

Reduction of artefacts caused by hip implants in CT-based attenuation-corrected PET images using 2-D interpolation of a virtual sinogram on an irregular grid

NARCIS (Netherlands)

Abdoli, Mehrsima; de Jong, Johan R.; Pruim, Jan; Dierckx, Rudi A. J. O.; Zaidi, Habib

2011-01-01

Purpose Metallic prosthetic replacements, such as hip or knee implants, are known to cause strong streaking artefacts in CT images. These artefacts likely induce over-or underestimation of the activity concentration near the metallic implants when applying CT-based attenuation correction of positron

Plasma cleaning and analysis of archeological artefacts from Sipan

Energy Technology Data Exchange (ETDEWEB)

Saettone, E A O [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo, CEP 05508-900 (Brazil); Matta, J A S da [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo, CEP 05508-900 (Brazil); Alva, W [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo, CEP 05508-900 (Brazil); Chubaci, J F O [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo, CEP 05508-900 (Brazil); Fantini, M C A [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo, CEP 05508-900 (Brazil); Galvao, R M O [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo, CEP 05508-900 (Brazil); Kiyohara, P [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo, CEP 05508-900 (Brazil); Tabacniks, M H [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo, CEP 05508-900 (Brazil)

2003-04-07

A novel procedure using plasma sputtering in an electron-cyclotron-resonance device has been applied to clean archeological MOCHE artefacts, unearthed at the Royal Tombs of Sipan. After successful cleaning, the pieces were analysed by a variety of complementary techniques, namely proton-induced x-ray emission, Rutherford backscattering spectroscopy, x-ray diffraction, electron microscopy, and inductively coupled plasma mass spectroscopy. With these techniques, it has been possible to not only determine the profiles of the gold and silver surface layers, but also to detect elements that may be relevant to explain the gilding techniques skillfully developed by the metal smiths of the MOCHE culture.

Corrosion of archaeological iron artefacts compared to modern iron at the waterlogged site Nydam, Denmark

DEFF Research Database (Denmark)

Matthiesen, Henning; Hilbert, Lisbeth Rischel; Gregory, David

2004-01-01

focuses solely on the iron objects. A three-pronged approach has been used in the studies in Nydam: Studies of the excavated artefacts, including the compositon of corrosion products and a mapping of their exact state of preservation. 2) Use of modern iron samples placed in the soil for studies of weight......Since 1859 several archaeological excavations have been carried out in Nydam, Denmark revealing a wealth of military equipment sacrificed in the period 200 - 500 AD. During the 1990's more than 16000 artefacts of mainly wood and iron were excavated within an area of only 600 m2. Due to the volume...... loss, corrosion potential, electrochemical impedance spectroscopy and electrical resistivity. 3) Measurements of environmental parameter such as water level, redox potential, oxygen concentration, soil pH, and the concentration of a range of dissolved species in the pore water. This presentation shows...

Electrocardiographic artefacts mimicking atrial tachycardia resulted in unnecessary diagnostic and therapeutic measures

OpenAIRE

Y-Hassan, Shams; Sylv?n, Christer

2013-01-01

Electrocardiographic (ECG) artefacts may closely simulate both supraventricular and ventricular tachycardias. We describe a case initially diagnosed as rapid atrial fibrillation, based on 12-lead surface ECG (especially the limb leads) and monitor tracing. The arrhythmia was resistant to beta blockers. Because of the at times apparently regular rhythm, an esophageal ECG recording was performed, and adenosine was administered. When the presumed atrial fibrillation terminated after sodium pento...

Reduction in respiratory motion artefacts on gadoxetate-enhanced MRI after training technicians to apply a simple and more patient-adapted breathing command

International Nuclear Information System (INIS)

Gutzeit, Andreas; Matoori, Simon; Weymarn, Constantin von; Reischauer, Carolin; Goyen, Matthias; Hergan, Klaus; Meissnitzer, Matthias; Forstner, Rosemarie; Froehlich, Johannes M.; Kolokythas, Orpheus; Soyka, Jan D.; Doert, Aleksis; Koh, Dow-Mu

2016-01-01

To investigate whether a trained group of technicians using a modified breathing command during gadoxetate-enhanced liver MRI reduces respiratory motion artefacts compared to non-trained technicians using a traditional breathing command. The gadoxetate-enhanced liver MR images of 30 patients acquired using the traditional breathing command and the subsequent 30 patients after training the technicians to use a modified breathing command were analyzed. A subgroup of patients (n = 8) underwent scans both by trained and untrained technicians. Images obtained using the traditional and modified breathing command were compared for the presence of breathing artefacts [respiratory artefact-based image quality scores from 1 (best) to 5 (non-diagnostic)]. There was a highly significant improvement in the arterial phase image quality scores in patients using the modified breathing command compared to the traditional one (P < 0.001). The percentage of patients with severe and extensive breathing artefacts in the arterial phase decreased from 33.3 % to 6.7 % after introducing the modified breathing command (P = 0.021). In the subgroup that underwent MRI using both breathing commands, arterial phase image quality improved significantly (P = 0.008) using the modified breathing command. Training technicians to use a modified breathing command significantly improved arterial phase image quality of gadoxetate-enhanced liver MRI. (orig.)

7 CFR 58.137 - Excluded milk.

Science.gov (United States)

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Excluded milk. 58.137 Section 58.137 Agriculture... Milk § 58.137 Excluded milk. A plant shall not accept milk from a producer if: (a) The milk has been in...) Three of the last five milk samples have exceeded the maximum bacterial estimate of 500,000 per ml...

20 CFR 404.1012 - Work excluded from employment.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Work excluded from employment. 404.1012... DISABILITY INSURANCE (1950- ) Employment, Wages, Self-Employment, and Self-Employment Income Work Excluded from Employment § 404.1012 Work excluded from employment. Certain kinds of work performed by an...

31 CFR 19.950 - Excluded Parties List System

Science.gov (United States)

2010-07-01

... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Excluded Parties List System 19.950 Section 19.950 Money and Finance: Treasury Office of the Secretary of the Treasury GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) Definitions § 19.950 Excluded Parties List System Excluded Parties...

X-ray fluorescence microscopy artefacts in elemental maps of topologically complex samples: Analytical observations, simulation and a map correction method

Science.gov (United States)

Billè, Fulvio; Kourousias, George; Luchinat, Enrico; Kiskinova, Maya; Gianoncelli, Alessandra

2016-08-01

XRF spectroscopy is among the most widely used non-destructive techniques for elemental analysis. Despite the known angular dependence of X-ray fluorescence (XRF), topological artefacts remain an unresolved issue when using X-ray micro- or nano-probes. In this work we investigate the origin of the artefacts in XRF imaging of topologically complex samples, which are unresolved problems in studies of organic matter due to the limited travel distances of low energy XRF emission from the light elements. In particular we mapped Human Embryonic Kidney (HEK293T) cells. The exemplary results with biological samples, obtained with a soft X-ray scanning microscope installed at a synchrotron facility were used for testing a mathematical model based on detector response simulations, and for proposing an artefact correction method based on directional derivatives. Despite the peculiar and specific application, the methodology can be easily extended to hard X-rays and to set-ups with multi-array detector systems when the dimensions of surface reliefs are in the order of the probing beam size.

Isosorbide dinitrate and nifedipine treatment of achalasia: a clinical, manometric and radionuclide evaluation

International Nuclear Information System (INIS)

Gelfond, M.; Rozen, P.; Gilat, T.

1982-01-01

The effects of sublingual isosorbide dinitrate (5 mg) and nifedipine (20 mg) were compared in 15 patients with achalasia. The parameters examined included the manometric measurement of the lower esophageal sphincter pressure, the radionuclide assessment of esophageal emptying and the clinical response. The mean basal lower esophageal sphincter pressure fell significantly after both drugs (p less than 0.01), with a maximum fall of 63.5% 10 min after receiving isosorbide dinitrate, but by only 46.7% 30 min after nifedipine. The esophageal radionuclide test meal retention was significantly less (p less than 0.01) only after receiving isosorbide dinitrate. The drug improved initial esophageal emptying by its effect on the lower esophageal sphincter and by relieving the test meal hold-up noted to occur at the junction of the upper and midesophagus. Eight patients cleared their test meal within 10 min after isosorbide dinitrate administration while only two did so after nifedipine. Subjectively, 13 patients had their dysphagia relieved by isosorbide dinitrate and 8 by nifedipine. However, this relief was not confirmed in 4 patients by the radionuclide study and they, as well as the other 3 patients who did not respond to therapy, were referred to pneumatic dilatation. Side effects were more prominent after nitrates. Three of the patients are currently receiving nifedipine and 5 patients received isosorbide dinitrate therapy for 8-14 mo. The radionuclide test meal is currently the best way of objectively evaluating drug therapy in patients with achalasia. Isosorbide dinitrate is more effective than nifedipine in relieving their symptoms

Isosorbide dinitrate and nifedipine treatment of achalasia: a clinical, manometric and radionuclide evaluation

Energy Technology Data Exchange (ETDEWEB)

Gelfond, M.; Rozen, P.; Gilat, T.

1982-11-01

The effects of sublingual isosorbide dinitrate (5 mg) and nifedipine (20 mg) were compared in 15 patients with achalasia. The parameters examined included the manometric measurement of the lower esophageal sphincter pressure, the radionuclide assessment of esophageal emptying and the clinical response. The mean basal lower esophageal sphincter pressure fell significantly after both drugs (p less than 0.01), with a maximum fall of 63.5% 10 min after receiving isosorbide dinitrate, but by only 46.7% 30 min after nifedipine. The esophageal radionuclide test meal retention was significantly less (p less than 0.01) only after receiving isosorbide dinitrate. The drug improved initial esophageal emptying by its effect on the lower esophageal sphincter and by relieving the test meal hold-up noted to occur at the junction of the upper and midesophagus. Eight patients cleared their test meal within 10 min after isosorbide dinitrate administration while only two did so after nifedipine. Subjectively, 13 patients had their dysphagia relieved by isosorbide dinitrate and 8 by nifedipine. However, this relief was not confirmed in 4 patients by the radionuclide study and they, as well as the other 3 patients who did not respond to therapy, were referred to pneumatic dilatation. Side effects were more prominent after nitrates. Three of the patients are currently receiving nifedipine and 5 patients received isosorbide dinitrate therapy for 8-14 mo. The radionuclide test meal is currently the best way of objectively evaluating drug therapy in patients with achalasia. Isosorbide dinitrate is more effective than nifedipine in relieving their symptoms.

Calibration artefacts in radio interferometry - III. Phase-only calibration and primary beam correction

Science.gov (United States)

Grobler, T. L.; Stewart, A. J.; Wijnholds, S. J.; Kenyon, J. S.; Smirnov, O. M.

2016-09-01

This is the third installment in a series of papers in which we investigate calibration artefacts. Calibration artefacts (also known as ghosts or spurious sources) are created when we calibrate with an incomplete model. In the first two papers of this series, we developed a mathematical framework which enabled us to study the ghosting mechanism itself. An interesting concomitant of the second paper was that ghosts appear in symmetrical pairs. This could possibly account for spurious symmetrization. Spurious symmetrization refers to the appearance of a spurious source (the antighost) symmetrically opposite an unmodelled source around a modelled source. The analysis in the first two papers indicates that the antighost is usually very faint, in particular, when a large number of antennas are used. This suggests that spurious symmetrization will mainly occur at an almost undetectable flux level. In this paper, we show that phase-only calibration produces an antighost that is N-times (where N denotes the number of antennas in the array) as bright as the one produced by phase and amplitude calibration and that this already bright ghost can be further amplified by the primary beam correction.

How useful is esophageal high resolution manometry in diagnosing gastroesophageal junction disruption: causes affecting this disruption and its relationship with manometric alterations and gastroesophageal reflux

Directory of Open Access Journals (Sweden)

Constanza Ciriza-de-los-Ríos

2014-01-01

Full Text Available Background: High-resolution manometry (HRM is a breakthrough in the morphological study of the gastroesophageal junction (GEJ and its degrees of disruption. Objectives: a Assessment of risk factors involved in the disruption of the GEJ in patients with gastroesophageal reflux (GER symptoms; b the relationship between the type of GEJ and GER demonstrated by 24 hours pH-monitoring; and c identification of the alterations in the manometric parameters related to the morphology of the GEJ. Methods: One hundred and fifteen patients with symptoms of GER studied with HRM and classified by the type of GEJ (type I: Normal; type II: Sliding; type III: Hiatal hernia. Twenty four hour pH-monitoring without proton pump inhibitors was performed in all of them. Epidemiological aspects, manometric parameters (Chicago 2012 classification and the pH-monitoring results were evaluated. Results: Age (OR 1.033 [1.006-1.060]; p = 0.16, BMI (OR 1.097 [1.022-1.176]; p = 0. 01 and abdominal perimeter (OR 1.034 [1.005-1.063]; p = 0.0215 were independent risk factors for the GEJ type III (area under the curve 0.70. Disruption of the GEJ was associated with a lower resting pressure (p = 0.006, greater length (p < 0.001 and greater esophageal shortening (p < 0.001. Abnormal acidic reflux was found in the total period (p = 0.015, standing (p = 0.022 and supine (p = 0.001 in patients with GEJ type II and III with respect to type I. Conclusions: Increased age, overweight and central obesity pose a higher risk of GEJ type III (hiatal hernia. The greater disruption of the GEJ is associated with lower resting pressure, esophageal shortening, and higher acid exposure in the pH-monitoring.

Computed tomography by reconstruction. Brain CT scanning. I. Basic physics, equipment, normal aspects, artefacts

International Nuclear Information System (INIS)

Chiras, J.; Palmieri, P.; Saudinos, J.; Salamon, G.

1980-01-01

The authors describe the physical basis, apparatus, normal images, and artefacts of computed tomography by reconstruction. Radio-anatomical sections enable clear comprehension of the computed tomography images. Other methods using computer reconstruction are outlined: tomography by Compton effect, tomography by positrons, tomography by gamma emission, tomography by protons, tomography by nuclear magnetic resonance [fr

Value of monoenergetic dual-energy CT (DECT) for artefact reduction from metallic orthopedic implants in post-mortem studies.

Science.gov (United States)

Filograna, Laura; Magarelli, Nicola; Leone, Antonio; Guggenberger, Roman; Winklhofer, Sebastian; Thali, Michael John; Bonomo, Lorenzo

2015-09-01

The aim of this ex vivo study was to assess the performance of monoenergetic dual-energy CT (DECT) reconstructions to reduce metal artefacts in bodies with orthopedic devices in comparison with standard single-energy CT (SECT) examinations in forensic imaging. Forensic and clinical impacts of this study are also discussed. Thirty metallic implants in 20 consecutive cadavers with metallic implants underwent both SECT and DECT with a clinically suitable scanning protocol. Extrapolated monoenergetic DECT images at 64, 69, 88, 105, 120, and 130 keV and individually adjusted monoenergy for optimized image quality (OPTkeV) were generated. Image quality of the seven monoenergetic images and of the corresponding SECT image was assessed qualitatively and quantitatively by visual rating and measurements of attenuation changes induced by streak artefact. Qualitative and quantitative analyses showed statistically significant differences between monoenergetic DECT extrapolated images and SECT, with improvements in diagnostic assessment in monoenergetic DECT at higher monoenergies. The mean value of OPTkeV was 137.6 ± 4.9 with a range of 130 to 148 keV. This study demonstrates that monoenergetic DECT images extrapolated at high energy levels significantly reduce metallic artefacts from orthopedic implants and improve image quality compared to SECT examination in forensic imaging.

Value of monoenergetic dual-energy CT (DECT) for artefact reduction from metallic orthopedic implants in post-mortem studies

Energy Technology Data Exchange (ETDEWEB)

Filograna, Laura [University of Zurich, Department of Forensic Medicine and Imaging, Institute of Forensic Medicine, Zurich (Switzerland); Catholic University of Rome, School of Medicine, University Hospital ' ' A. Gemelli' ' , Department of Radiological Sciences, Rome (Italy); Magarelli, Nicola; Leone, Antonio; Bonomo, Lorenzo [Catholic University of Rome, School of Medicine, University Hospital ' ' A. Gemelli' ' , Department of Radiological Sciences, Rome (Italy); Guggenberger, Roman; Winklhofer, Sebastian [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Thali, Michael John [University of Zurich, Department of Forensic Medicine and Imaging, Institute of Forensic Medicine, Zurich (Switzerland)

2015-09-15

The aim of this ex vivo study was to assess the performance of monoenergetic dual-energy CT (DECT) reconstructions to reduce metal artefacts in bodies with orthopedic devices in comparison with standard single-energy CT (SECT) examinations in forensic imaging. Forensic and clinical impacts of this study are also discussed. Thirty metallic implants in 20 consecutive cadavers with metallic implants underwent both SECT and DECT with a clinically suitable scanning protocol. Extrapolated monoenergetic DECT images at 64, 69, 88, 105, 120, and 130 keV and individually adjusted monoenergy for optimized image quality (OPTkeV) were generated. Image quality of the seven monoenergetic images and of the corresponding SECT image was assessed qualitatively and quantitatively by visual rating and measurements of attenuation changes induced by streak artefact. Qualitative and quantitative analyses showed statistically significant differences between monoenergetic DECT extrapolated images and SECT, with improvements in diagnostic assessment in monoenergetic DECT at higher monoenergies. The mean value of OPTkeV was 137.6 ± 4.9 with a range of 130 to 148 keV. This study demonstrates that monoenergetic DECT images extrapolated at high energy levels significantly reduce metallic artefacts from orthopedic implants and improve image quality compared to SECT examination in forensic imaging. (orig.)

Value of monoenergetic dual-energy CT (DECT) for artefact reduction from metallic orthopedic implants in post-mortem studies

International Nuclear Information System (INIS)

Filograna, Laura; Magarelli, Nicola; Leone, Antonio; Bonomo, Lorenzo; Guggenberger, Roman; Winklhofer, Sebastian; Thali, Michael John

2015-01-01

The aim of this ex vivo study was to assess the performance of monoenergetic dual-energy CT (DECT) reconstructions to reduce metal artefacts in bodies with orthopedic devices in comparison with standard single-energy CT (SECT) examinations in forensic imaging. Forensic and clinical impacts of this study are also discussed. Thirty metallic implants in 20 consecutive cadavers with metallic implants underwent both SECT and DECT with a clinically suitable scanning protocol. Extrapolated monoenergetic DECT images at 64, 69, 88, 105, 120, and 130 keV and individually adjusted monoenergy for optimized image quality (OPTkeV) were generated. Image quality of the seven monoenergetic images and of the corresponding SECT image was assessed qualitatively and quantitatively by visual rating and measurements of attenuation changes induced by streak artefact. Qualitative and quantitative analyses showed statistically significant differences between monoenergetic DECT extrapolated images and SECT, with improvements in diagnostic assessment in monoenergetic DECT at higher monoenergies. The mean value of OPTkeV was 137.6 ± 4.9 with a range of 130 to 148 keV. This study demonstrates that monoenergetic DECT images extrapolated at high energy levels significantly reduce metallic artefacts from orthopedic implants and improve image quality compared to SECT examination in forensic imaging. (orig.)

In Vitro Validation of an Artefact Suppression Algorithm in X-Ray Phase-Contrast Computed Tomography.

Science.gov (United States)

Sunaguchi, Naoki; Yuasa, Tetsuya; Hirano, Shin-Ichi; Gupta, Rajiv; Ando, Masami

2015-01-01

X-ray phase-contrast tomography can significantly increase the contrast-resolution of conventional attenuation-contrast imaging, especially for soft-tissue structures that have very similar attenuation. Just as in attenuation-based tomography, phase contrast tomography requires a linear dependence of aggregate beam direction on the incremental direction alteration caused by individual voxels along the path of the X-ray beam. Dense objects such as calcifications in biological specimens violate this condition. There are extensive beam deflection artefacts in the vicinity of such structures because they result in large distortion of wave front due to the large difference of refractive index; for such large changes in beam direction, the transmittance of the silicon analyzer crystal saturates and is no longer linearly dependent on the angle of refraction. This paper describes a method by which these effects can be overcome and excellent soft-tissue contrast of phase tomography can be preserved in the vicinity of such artefact-producing structures.

Minimally destructive DNA extraction from archaeological artefacts made from whale baleen

DEFF Research Database (Denmark)

Sinding, Mikkel Holger Strander; Gilbert, Tom; Grønnow, Bjarne

2012-01-01

Here we demonstrate the successful extraction and amplification of target species DNA from artefacts made of whale baleen collected from excavations of past palaeo-Eskimo and Inuit cultures in Greenland. DNA was successfully extracted and amplified from a single baleen bristle of 1.5 cm length...... genetic studies. We conclude that genetic investigation of historical baleen collections can contribute to our knowledge of the prehistoric population genetics of baleen whales, for example by quantifying the impact of modern whaling on the genetic diversity of bowhead whales....

Laryngeal mask airway (LMA) artefact resulting in MRI misdiagnosis

International Nuclear Information System (INIS)

Schieble, Thomas; Patel, Anuradha; Davidson, Melissa

2008-01-01

We report a 7-year-old child who underwent brain MRI for a known seizure disorder. The technique used for general anesthesia included inhalation induction followed by placement of a laryngeal mask airway (LMA) for airway maintenance. Because the reviewing radiologist was unfamiliar with the use of an LMA during anesthesia, and because the attending anesthesiologist did not communicate his technique to the radiologist, an MRI misdiagnosis was reported because of artefact created by the in situ LMA. As a result of this misdiagnosis the child was subjected to unnecessary subsequent testing to rule out a reported anatomic abnormality induced by the LMA. Our case illustrates the need for coordination of patient care among hospital services. (orig.)

Laryngeal mask airway (LMA) artefact resulting in MRI misdiagnosis

Energy Technology Data Exchange (ETDEWEB)

Schieble, Thomas [University of Medicine and Dentistry of New Jersey, Department of Anesthesiology, New Jersey Medical School, Newark, NJ (United States); Maimonides Medical Center, Department of Anesthesiology, Brooklyn, NY (United States); Patel, Anuradha; Davidson, Melissa [University of Medicine and Dentistry of New Jersey, Department of Anesthesiology, New Jersey Medical School, Newark, NJ (United States)

2008-03-15

We report a 7-year-old child who underwent brain MRI for a known seizure disorder. The technique used for general anesthesia included inhalation induction followed by placement of a laryngeal mask airway (LMA) for airway maintenance. Because the reviewing radiologist was unfamiliar with the use of an LMA during anesthesia, and because the attending anesthesiologist did not communicate his technique to the radiologist, an MRI misdiagnosis was reported because of artefact created by the in situ LMA. As a result of this misdiagnosis the child was subjected to unnecessary subsequent testing to rule out a reported anatomic abnormality induced by the LMA. Our case illustrates the need for coordination of patient care among hospital services. (orig.)

Diffusion-weighted imaging of the liver at 3 T using section-selection gradient reversal: emphasis on chemical shift artefacts and lesion conspicuity

International Nuclear Information System (INIS)

Lee, J.S.; Kim, Y.K.; Jeong, W.K.; Choi, D.; Lee, W.J.

2015-01-01

Aim: To assess the value of section-selection gradient reversal (SSGR) in liver diffusion-weighted imaging (DWI) by comparing it to conventional DWI with an emphasis on chemical shift artefacts and lesion conspicuity. Materials and methods: Forty-eight patients (29 men and 19 women; age range 33–80 years) with 48 liver lesions underwent two DWI examinations using spectral presaturation with inversion recovery fat suppression with and without SSGR at 3 T. Two reviewers evaluated each DWI (b = 100 and b = 800 image) with respect to chemical shift artefacts and liver lesion conspicuity using five-point scales and performed pairwise comparisons between the two DWIs. The signal-to-noise ratio (SNR) of the liver and the lesion and the lesion–liver contrast-to-noise ratio (CNR) were also calculated. Results: SSGR-DWI was significantly better than conventional DWI with respect to chemical shift artefacts and lesion conspicuity in both separate reviews and pairwise comparisons (p < 0.05). There were significant differences in the SNR of the liver (b = 100 and b = 800 images) and lesion (b = 800) between SSGR-DWI and conventional DWI (p < 0.05). Conclusion: Applying the SSGR method to DWI using SPIR fat suppression at 3 T could significantly reduce chemical shift artefacts without incurring additional acquisition time or SNR penalties, which leads to increased conspicuity of focal liver lesions. - Highlights: • Chemical shift artefact in liver DWI is markedly decreased by applying SSGR. • Liver lesion conspicuity is improved by applying SSGR to DWI. • In SNR of the liver, SSGR-DWI is better than conventional DWI

Automated correction of spin-history related motion artefacts in fMRI : Simulated and phantom data

NARCIS (Netherlands)

Muresan, L; Renken, R.; Roerdink, J.B.T.M.; Duifhuis, H.

This paper concerns the problem of correcting spin-history artefacts in fMRI data. We focus on the influence of through-plane motion on the history of magnetization. A change in object position will disrupt the tissue’s steady-state magnetization. The disruption will propagate to the next few

8 CFR 1241.20 - Aliens ordered excluded.

Science.gov (United States)

2010-01-01

... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Aliens ordered excluded. 1241.20 Section 1241.20 Aliens and Nationality EXECUTIVE OFFICE FOR IMMIGRATION REVIEW, DEPARTMENT OF JUSTICE IMMIGRATION REGULATIONS APPREHENSION AND DETENTION OF ALIENS ORDERED REMOVED Deportation of Excluded Aliens...

Manometric assessment of esophageal motor function in patients with primary biliary cirrhosis.

Science.gov (United States)

Bektas, Mehmet; Seven, Gulseren; Idilman, Ramazan; Yakut, Mustafa; Doğanay, Beyza; Kabacam, Gökhan; Ustun, Yusuf; Korkut, Esin; Kalkan, Çağdaş; Sahin, Günay; Cetinkaya, Hulya; Bozkaya, Hakan; Yurdaydin, Cihan; Bahar, Kadir; Cinar, Kubilay; Soykan, Irfan

2014-03-01

Primary biliary cirrhosis is associated with other autoimmune diseases including Sjögren's syndrome, and scleroderma. Esophageal dysmotility is well known in scleroderma, and Sjögren's syndrome. The aim of this study is to investigate whether any esophageal motor dysfunction exists in patients with primary biliary cirrhosis. The study was performed in 37 patients (36 women, mean age: 56.29 ± 10.01 years) who met diagnostic criteria for primary biliary cirrhosis. Thirty-seven functional dyspepsia patients, were also included as a control group. Patients entering the study were asked to complete a symptom questionnaire. Distal esophageal contraction amplitude, and lower esophageal sphincter resting pressure were assessed. Manometric findings in primary biliary cirrhosis patients vs. controls were as follows: Median lower esophageal sphincter resting pressure (mmHg): (24 vs 20, p=0.033); median esophageal contraction amplitude (mmHg): (71 vs 56, p=0.050); mean lower esophageal sphincter relaxation duration (sc, x ± SD): (6.10 ± 1.18 vs 8.29 ± 1.92, pesophageal sphincter relaxation (%) (96 vs 98, p=0.019); respectively. No significant differences were evident in median peak velocity (sc) (3.20 vs 3.02, p=0.778) between patients with primary biliary cirrhosis and the functional dyspepsia patients. Esophageal dysmotility was found in 17 (45.9%) primary biliary cirrhosis patients (non-specific esophageal motor disorder in ten patients, hypomotility of esophagus in five patients, nutcracker esophagus in one patient and hypertensive lower esophageal sphincter in one patient). Esophageal dysmotility was detected in 45.9% of patients. The study suggests that subclinic esophageal dysmotility is frequent in patients with primary biliary cirrhosis. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

Assessment of filament led bulbs with respect to temporal light artefacts

DEFF Research Database (Denmark)

Lindén, Johannes; Thorseth, Anders; Corell, Dennis Dan

2017-01-01

Temporal light artefacts, abbreviated TLAs (including flicker, stroboscopic effect and phantom arrays), i.e. undesired time modulation in luminance from a light source, has shown to be a threat to wider SSL adoption especially related to dimming functions and low-quality LED products. This is due...... to the effects that both noticeable and unperceivable TLAs have on human perception and wellbeing. In the present work a number of filament LED bulbs, currently available on the market, are assessed primarily with respect to TLAs, but also with respect to photometric, colorimetric and efficiency properties...

Clinical and manometric evaluation of women with chronic anal fissure before and after internal subcutaneous lateral sphincterotomy

Directory of Open Access Journals (Sweden)

Silvana Marques e Silva

2012-06-01

Full Text Available OBJECTIVE: To evaluate clinical and manometric parameters of chronic anal fissure females undergoing lateral internal sphincterotomy (LIS. METHODS: A total of eight women with chronic anal fissure who underwent LIS were included in this study. The preoperative assessment was performed one week before surgery and included general and anorectal examination, anorectal manometry, and Jorge Wexner questionnaire. The post operative follow up was made every 15 days until complete healing. Jorge Wexner questionnaires and anorectal manometry were repeated at 1 month and 3 months after the surgery. Time to healing, manometric changes and complications were assessed. RESULTS: All patients had preoperative increased anal resting pressure. The resting pressures and anal canal length were significantly decreased 3 months after surgery. Patients' complaints of itching and bleeding were also reduced. Fissures healed in 7 patients and median healing time was 45 days. No complications were observed due to the procedure. One patient had transient incontinence to flatus. CONCLUSION: Lateral internal sphincterotomy provided clinical improvement and reduced resting pressure of the internal anal sphincter in women with chronic anal fissure.OBJETIVO: Avaliar a evolução clínica e manométrica de mulheres com fissura anal crônica submetidas à esfincterotomia lateral interna subcutânea. MÉTODOS: Estudo prospectivo com oito pacientes. A avaliação inicial foi realizada por meio de questionários, exame físico e manometria anorretal na semana anterior ao procedimento cirúrgico. Durante o período pós-operatório, as pacientes foram avaliadas clinicamente a cada 15 dias, até a cicatrização completa. Os questionários e a manometria anorretal foram repetidos 1 mês e 3 meses após a operação. Foi avaliado o tempo para cicatrização da fissura, as alterações manométricas e as complicações decorrentes do procedimento. RESULTADOS: Todas as pacientes

A new method to compensate impedance artefacts for Li-ion batteries with integrated micro-reference electrodes

NARCIS (Netherlands)

Raijmakers, L.H.J.; Notten, P.H.L.; Lammers, M.J.G.

2017-01-01

In order to measure the electrochemical characteristics of both electrodes inside Li-ion batteries, micro-reference electrodes (μREF) turned out to be very useful. However, measuring the electrochemical impedance with respect to μREF can lead to severe measurement artefacts, making a detailed

Casino Self- and Forced Excluders' Gambling Behavior Before and After Exclusion.

Science.gov (United States)

Kotter, Roxana; Kräplin, Anja; Bühringer, Gerhard

2018-06-01

Casino exclusion programs are intended to prevent or limit gambling-related harm. Although previous research showed that self-exclusion is associated with reduced gambling, it remains unknown whether self- and forced excluded subjects show different patterns of gambling behavior and if exclusion from casino gambling affects all gambling activities. The present study retrospectively investigated (1) the role of voluntariness of exclusion for the first time, and (2) general gambling behavior of excluded individuals before and after exclusion. A total of N = 215 casino excluders (self-excluders: n = 187, forced excluders: n = 28) completed an online survey or a face-to-face interview up to 8 years after enrollment. Self- and forced excluders showed similar rates of abstinence (self-excluders: 19.3%, forced excluders: 28.6%) and reduction (self-excluders: 67.4%, forced excluders: 60.7%), even though forced excluders reported a significantly greater initial gambling intensity compared to self-excluders (e.g., pre-exclusion gambling time; self-excluders: 3.2 days/week, forced excluders: 4.3 days/week). Overall, results indicated that 20.5% of excluders stopped all gambling activities and another 66.5% reduced their gambling. Those who continued gambling significantly reduced this behavior in every segment, except for gambling halls. Findings indicate that self- and forced exclusion are associated with similarly reduced gambling behavior, even in non-excluded segments. However, unchanged gambling in gambling halls emphasizes the importance to implement consistent exclusion programs over all gambling segments.

Registration concepts for the just-in-time artefact correction by means of virtual computed tomography

Energy Technology Data Exchange (ETDEWEB)

Kasperl, St.; Franz, M. [Fraunhofer Development Center for X-ray Technology EZRT, a cooperative dept. of the Fraunhofer Institutes IZFP Saarbrucken and IIS Erlangen, Furth (Germany)

2007-07-01

This article deals with the enhancement of accuracy in CT by just-in-time correction of artefacts (beam hardening, scattered radiation) caused by the interaction of X-rays with matter. The so called EAR method needs for simulation a registration of the object. Therefore the article presents two different registration concepts. (authors)

Registration concepts for the just-in-time artefact correction by means of virtual computed tomography

International Nuclear Information System (INIS)

Kasperl, St.; Franz, M.

2007-01-01

This article deals with the enhancement of accuracy in CT by just-in-time correction of artefacts (beam hardening, scattered radiation) caused by the interaction of X-rays with matter. The so called EAR method needs for simulation a registration of the object. Therefore the article presents two different registration concepts. (authors)

Metallic artefact reduction with monoenergetic dual-energy CT: systematic ex vivo evaluation of posterior spinal fusion implants from various vendors and different spine levels.

Science.gov (United States)

Guggenberger, R; Winklhofer, S; Osterhoff, G; Wanner, G A; Fortunati, M; Andreisek, G; Alkadhi, H; Stolzmann, P

2012-11-01

To evaluate optimal monoenergetic dual-energy computed tomography (DECT) settings for artefact reduction of posterior spinal fusion implants of various vendors and spine levels. Posterior spinal fusion implants of five vendors for cervical, thoracic and lumbar spine were examined ex vivo with single-energy (SE) CT (120 kVp) and DECT (140/100 kVp). Extrapolated monoenergetic DECT images at 64, 69, 88, 105 keV and individually adjusted monoenergy for optimised image quality (OPTkeV) were generated. Two independent radiologists assessed quantitative and qualitative image parameters for each device and spine level. Inter-reader agreements of quantitative and qualitative parameters were high (ICC = 0.81-1.00, κ = 0.54-0.77). HU values of spinal fusion implants were significantly different among vendors (P metallic artefacts from implants than SECT. Use of individual keV values for vendor and spine level is recommended. • Artefacts pose problems for CT following posterior spinal fusion implants. • CT images are interpreted better with monoenergetic extrapolation using dual-energy (DE) CT. • DECT extrapolation improves image quality and reduces metallic artefacts over SECT. • There were considerable differences in monoenergy values among vendors and spine levels. • Use of individualised monoenergy values is indicated for different metallic hardware devices.

Preliminary Results of Ocular Artefacts Identification in EEC Series by Neural Network

OpenAIRE

Kofronova, M.

1996-01-01

The human electroencephalogram (EEG), is record of the electrical activity of the brain and contains useful diagnostic information on a variety of neurological disorders. Normal EEG signal are usually registered from electrodes placed on the scalp, and are often very small in amplitude, of 20 µV. The EEG, like all biomedical signals, is very susceptible to a variety of large signal contamination or artefacts (signals of other than brain activity) which reduce its clinical usefulness. For e...

Explorative Materiality and Knowledge. The Role of Creative Exploration and Artefacts in Design Research

Directory of Open Access Journals (Sweden)

Kristina Niedderer

2013-08-01

Full Text Available Juxtaposing the nature of design and the foundations of research in the traditional science and humanities disciplines puts their differences into sharp relief. The comparison highlights the key characteristics of design – its creative and experiential nature – which any design research must take into account, as well as the theoretical foundations of research. The aim of this article is to develop an understanding of the ontological, epistemological and methodological issues of design research, and to offer a framework that can embrace equally the notions of creativity and experiential knowledge, and of academic rigour. Furthermore,the potential roles of the design process and artefact within research are examined within this theoretical framework, which suggests that design processes and artefacts can – if appropriately framed – play an important partin the research process, facilitating an approach commensurate with the aims ofdesign enquiry. A case study of the Niedderer’s own work serves to illustratethe balance and integration of theory and (creative practice within the research process, and how this integration can enable a multi-layered contribution to the theoretical and practical advancement of the field.

Factors controlling headspace pressure in a manual manometric BMP method can be used to produce a methane output comparable to AMPTS.

Science.gov (United States)

Himanshu, H; Voelklein, M A; Murphy, J D; Grant, J; O'Kiely, P

2017-08-01

The manual manometric biochemical methane potential (mBMP) test uses the increase in pressure to calculate the gas produced. This gas production may be affected by the headspace volume in the incubation bottle and by the overhead pressure measurement and release (OHPMR) frequency. The biogas and methane yields of cellulose, barley, silage and slurry were compared with three incubation bottle headspace volumes (50, 90 and 180ml; constant 70ml total medium) and four OHPMR frequencies (daily, each third day, weekly and solely at the end of experiment). The methane yields of barley, silage and slurry were compared with those from an automated volumetric method (AMPTS). Headspace volume and OHPMR frequency effects on biogas yield were mediated mainly through headspace pressure, with the latter having a negative effect on the biogas yield measured and relatively little effect on methane yield. Two mBMP treatments produced methane yields equivalent to AMPTS. Copyright © 2017 Elsevier Ltd. All rights reserved.

Analytical artefacts in the speciation of arsenic in clinical samples

International Nuclear Information System (INIS)

Slejkovec, Zdenka; Falnoga, Ingrid; Goessler, Walter; Elteren, Johannes T. van; Raml, Reingard; Podgornik, Helena; Cernelc, Peter

2008-01-01

Urine and blood samples of cancer patients, treated with high doses of arsenic trioxide were analysed for arsenic species using HPLC-HGAFS and, in some cases, HPLC-ICPMS. Total arsenic was determined with either flow injection-HGAFS in urine or radiochemical neutron activation analysis in blood fractions (in serum/plasma, blood cells). The total arsenic concentrations (during prolonged, daily/weekly arsenic trioxide therapy) were in the μg mL -1 range for urine and in the ng g -1 range for blood fractions. The main arsenic species found in urine were As(III), MA and DMA and in blood As(V), MA and DMA. With proper sample preparation and storage of urine (no preservation agents/storage in liquid nitrogen) no analytical artefacts were observed and absence of significant amounts of alleged trivalent metabolites was proven. On the contrary, in blood samples a certain amount of arsenic can get lost in the speciation procedure what was especially noticeable for the blood cells although also plasma/serum gave rise to some disappearance of arsenic. The latter losses may be attributed to precipitation of As(III)-containing proteins/peptides during the methanol/water extraction procedure whereas the former losses were due to loss of specific As(III)-complexing proteins/peptides (e.g. cysteine, metallothionein, reduced GSH, ferritin) on the column (Hamilton PRP-X100) during the separation procedure. Contemporary analytical protocols are not able to completely avoid artefacts due to losses from the sampling to the detection stage so that it is recommended to be careful with the explanation of results, particularly regarding metabolic and pharmacokinetic interpretations, and always aim to compare the sum of species with the total arsenic concentration determined independently

X-ray microtomography scanner using time-delay integration for elimination of ring artefacts in the reconstructed image

International Nuclear Information System (INIS)

Davis, G.R.; London Univ.; Elliott, J.C.; London Univ.

1997-01-01

Most X-ray microtomography scanners work on the same principle as third-generation medical CT scanners, that is, the same point in each projection is measured by the same detector element. This leads to ring artefacts in the reconstructed image if the X-ray sensitivities of the individual detector elements, after any analytical correction, are not all identical. We have developed an X-ray microtomography scanner which uses the time-delay integration method of imaging with a CCD detector to average the characteristics of all the detector elements in each linear projection together. This has the added advantage of allowing specimens which are larger than the detector and X-ray field to be scanned. The device also uses a novel mechanical stage to ''average out'' inhomogeneities in the X-ray field. The results show that ring artefacts in microtomographic images are eliminated using this technique. (orig.)

29 CFR 778.225 - Talent fees excludable under regulations.

Science.gov (United States)

2010-07-01

... 29 Labor 3 2010-07-01 2010-07-01 false Talent fees excludable under regulations. 778.225 Section... Payments That May Be Excluded From the âRegular Rateâ Talent Fees in the Radio and Television Industry § 778.225 Talent fees excludable under regulations. Section 7(e)(3) provides for the exclusion from the...

Reduction of CT beam hardening artefacts of ethylene vinyl alcohol copolymer by variation of the tantalum content: evaluation in a standardized aortic endoleak phantom

International Nuclear Information System (INIS)

Treitl, Karla M.; Scherr, Michael; Foerth, Monika; Braun, Franziska; Maxien, Daniel; Treitl, Marcus

2015-01-01

Our aim was to develop an aortic stent graft phantom to simulate endoleak treatment and to find a tantalum content (TC) of ethylene-vinyl-alcohol-copolymer that causes fewer computed tomography (CT) beam hardening artefacts, but still allows for fluoroscopic visualization. Ethylene-vinyl-alcohol-copolymer specimens of different TC (10-50 %, and 100 %) were injected in an aortic phantom bearing a stent graft and endoleak cavities with simulated re-perfusion. Fluoroscopic visibility of the ethylene-vinyl-alcohol-copolymer specimens was analyzed. In addition, six radiologists analyzed endoleak visibility, and artefact intensity of ethylene-vinyl-alcohol-copolymer in CT. Reduction of TC significantly decreased CT artefact intensity of ethylene-vinyl-alcohol-copolymer and increased visibility of endoleak re-perfusion (p < 0.000). It also significantly decreased fluoroscopic visibility of ethylene-vinyl-alcohol-copolymer (R = 0.883, p ≤ 0.01), and increased the active embolic volumes prior to visualization (Δ ≥ 40 μl). Ethylene-vinyl-alcohol-copolymer specimens with a TC of 45-50 % exhibited reasonable visibility, a low active embolic volume and a tolerable CT artefact intensity. The developed aortic stent graft phantom allows for a reproducible simulation of embolization of endoleaks. The data suggest a reduction of the TC of ethylene-vinyl-alcohol-copolymer to 45 -50 % of the original, to interfere less with diagnostic imaging in follow-up CT examinations, while still allowing for fluoroscopic visualization. (orig.)

Decreased CSF-flow artefacts in T2 imaging of the cervical spine with periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER/BLADE)

International Nuclear Information System (INIS)

Ragoschke-Schumm, Andreas; Schmidt, Peter; Mayer, Thomas E.; Schumm, Julia; Reimann, Georg; Mentzel, Hans-Joachim; Kaiser, Werner A.

2011-01-01

The cervical spine is prone to artefacts in T2 MR-imaging due to patient movements and cerebrospinal fluid flow. The periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER/BLADE) acquisition method was developed to reduce motion artefacts. We sought to determine if T2-BLADE is superior to T2-TSE with conventional k-space reading. Twenty-five patients were examined using a 1.5 T MR-scanner. T2-weighted imaging of the cervical spine in sagittal and axial orientation using conventional or BLADE k-space reading was performed. Spinal cord, subarachnoid space, vertebrae and discs were evaluated by two independent observers using a scale from 0 (non-diagnostic) to 3 (excellent). Interobserver correlation was assessed as Cohen's kappa. Results of Mann-Whitney U test with p < 0.05 were regarded as significant. Furthermore, the investigators were asked for subjective evaluation in consensus. Overall interobserver accuracy of κ = 0.91 was obtained. Comparison of sagittal images showed better values for all investigated structures in T2-BLADE: spinal cord (TSE/BLADE: 1.52/2.04; p < 0.001), subarachnoid space (1.36/2.06; p < 0.001) and vertebrae/discs (1.66/2.86; p < 0.001). Comparison of axial images showed better values in T2-BLADE for spinal cord (1.68/1.86; p = 0.149) and vertebrae/discs (1.0/1.96: p < 0.001) while subarachnoid space was better to be evaluated in conventional T2-TSE (1.94/1.12; p < 0.001). In sagittal orientation, motion- and CSF-flow artefacts were reduced in T2-BLADE. In axial orientation, however, CSF-flow artefacts were pronounced in T2-BLADE. The image quality of the sagittal T2-BLADE sequences was significantly better than the T2-TSE and acquired in less time. In axial orientation, increased CSF-flow artefacts may reduce accuracy of structures in the subarachnoid space. (orig.)

Elemental analysis of artefacts - establishing external beam PIXE

International Nuclear Information System (INIS)

Alves, A.; Johnston, P.; Short, R.; Bubb, I.

1999-01-01

The development of an external PIXE facility on the 1 MV Tandetron accelerator at RMIT has led to a wide range of research possibilities. A proton beam, generated inside a vacuum is brought into air via an Au coated Kapton foil exit window (thickness 8μm, diameter 0.35mm). Monitoring of the beam intensity is achieved by detecting backscattered protons from the inside Au coating on the window. Artefacts, which may be too large to be placed inside the vacuum, are positioned in the beamline opposite the exit window. An optical system consisting of a CCD camera, alignment laser and two mirrors allows viewing of a region of the target 10mm x 10mm. This technique provides quantitative analysis of elements in the pigments used in paintings and on ceramics, which is a valuable tool in art conservation and authentication. Application of the technique to a ceramic sample from the historic house 'Viewbank' is described

Comparison of Selected Properties of Shellac Varnish for Restoration and Polyurethane Varnish for Reconstruction of Historical Artefacts

Directory of Open Access Journals (Sweden)

Kristýna Šimůnková

2018-03-01

Full Text Available At present, many historical artefacts and furniture are only reconstructed and not restored. They are preserved in terms of material reparation, but their historical value decreases significantly. This work is focused on the comparison of the resistance of high-gloss polyurethane varnish with traditional shellac varnish. The varnishes were applied to oak wood and exposed to interior artificial accelerated ageing in Xenotest. Before and after ageing, cold liquid-resistance tests were performed on the tested specimens and gloss, colour, and adhesion were also evaluated. The structures of the surfaces were also analysed using a confocal laser scanning microscope. As expected, polyurethane varnish was much more durable than shellac varnish. Interestingly, shellac varnish was fairly resistant to water at the beginning, but this resistance was greatly reduced after artificial accelerated ageing. This illustrates the importance of sheltering the shellac treated artefacts in stable temperature-humidity conditions with the least possible effect of solar radiation.

The use of radiation in the study of cultural heritage artefacts

Science.gov (United States)

Creagh, Dudley; Otieno-Alego, Vincent; Treasure, Alana; Kubik, Maria; Hallam, David

2017-08-01

Patrons of art galleries and museums, tourists visiting historic buildings, and sightseers viewing archaeological sites are generally unaware of the extent to which science and technology has contributed to the value of what they see. Many countries rely on cultural tourism to generate national wealth. The use of radiation of many kinds to assist in the conservation/restoration of cultural heritage artefacts is described in this paper. In particular, the paper will describe studies of the pigments used in historic Australian Indigenous art, the degradation of manuscripts written using iron-gall inks, the protection of statues against corrosion and the selection of lubricants for use in old machinery.

Plasma cleaning and analysis of archeological artefacts from Sipán

Science.gov (United States)

Saettone, E. A. O.; da Matta, J. A. S.; Alva, W.; Chubaci, J. F. O.; Fantini, M. C. A.; Galvão, R. M. O.; Kiyohara, P.; Tabacniks, M. H.

2003-04-01

A novel procedure using plasma sputtering in an electron-cyclotron-resonance device has been applied to clean archeological MOCHE artefacts, unearthed at the Royal Tombs of Sipán. After successful cleaning, the pieces were analysed by a variety of complementary techniques, namely proton-induced x-ray emission, Rutherford backscattering spectroscopy, x-ray diffraction, electron microscopy, and inductively coupled plasma mass spectroscopy. With these techniques, it has been possible to not only determine the profiles of the gold and silver surface layers, but also to detect elements that may be relevant to explain the gilding techniques skillfully developed by the metal smiths of the MOCHE culture.

Human brain receptor autoradiography using whole hemisphere sections: a general method that minimizes tissue artefacts

International Nuclear Information System (INIS)

Quirion, R.; Robitaille, Y.; Martial, J.; Chabot, J.G.; Lemoine, P.; Pilapil, C.; Dalpe, M.

1987-01-01

A general method for the preparation of high-quality, mostly ice-crystal-artefact-free whole human brain hemisphere sections is described. Upon receipt, hemispheres are divided; one is then fixed in buffered 10% formalin for neuropathological analysis while the other is cut in 8-10-mm-thick coronal slices that are then rapidly frozen in 2-methylbutane at -40 degrees C (10-15 sec) before being placed in the brain bank at -80 degrees C. Such rapid freezing markedly decreases the formation of ice-crystal artefacts. Whole-hemisphere 20-micron thick sections are then cut and mounted onto lantern-type gelatin-coated slides. These sections are subsequently used for both qualitative and quantitative in vitro receptor autoradiography. Examples of data obtained are given by using various radioligands labelling classical neutrotransmitter, neuropeptide, enzyme, and ion channel receptor binding sites. This method should be useful for the obtention of various receptor maps in human brain. Such information could be most useful for in vivo receptor visualization studies using positron emission tomography (PET) scanning. It could also indicate if a given receptor population is specifically and selectively altered in certain brain diseases, eventually leading to the development of new therapeutic approaches

Robust motion artefact resistant circuit for calculation of Mean Arterial Pressure from pulse transit time.

Science.gov (United States)

Bhattacharya, Tinish; Gupta, Ankesh; Singh, Salam ThoiThoi; Roy, Sitikantha; Prasad, Anamika

2017-07-01

Cuff-less and non-invasive methods of Blood Pressure (BP) monitoring have faced a lot of challenges like stability, noise, motion artefact and requirement for calibration. These factors are the major reasons why such devices do not get approval from the medical community easily. One such method is calculating Blood Pressure indirectly from pulse transit time (PTT) obtained from electrocardiogram (ECG) and Photoplethysmogram (PPG). In this paper we have proposed two novel analog signal conditioning circuits for ECG and PPG that increase stability, remove motion artefacts, remove the sinusoidal wavering of the ECG baseline due to respiration and provide consistent digital pulses corresponding to blood pulses/heart-beat. We have combined these two systems to obtain the PTT and then correlated it with the Mean Arterial Pressure (MAP). The aim was to perform major part of the processing in analog domain to decrease processing load over microcontroller so as to reduce cost and make it simple and robust. We have found from our experiments that the proposed circuits can calculate the Heart Rate (HR) with a maximum error of ~3.0% and MAP with a maximum error of ~2.4% at rest and ~4.6% in motion.

What is the Right to Exclude Immigrants?

DEFF Research Database (Denmark)

Lægaard, Sune

2010-01-01

It is normally taken for granted that states have a right to control immigration into their territory. When immigration is raised as a normative issue two questions become salient, one about what the right to exclude is, and one about whether and how it might be justified. This paper considers...... the first question. The paper starts by noting that standard debates about immigration have not addressed what the right to exclude is. Standard debates about immigration furthermore tend to result either in fairly strong cases for open borders or in denials that considerations of justice apply...... to immigration at all, which results in state discretion positions. This state of debate is both theoretically unsatisfactory and normatively implausible. The paper therefore explores an alternative approach to the right to exclude immigrants from the perspective of recent debates about the territorial rights...

Artefact in Physiological Data Collected from Patients with Brain Injury: Quantifying the Problem and Providing a Solution Using a Factorial Switching Linear Dynamical Systems Approach.

Science.gov (United States)

Georgatzis, Konstantinos; Lal, Partha; Hawthorne, Christopher; Shaw, Martin; Piper, Ian; Tarbert, Claire; Donald, Rob; Williams, Christopher K I

2016-01-01

High-resolution, artefact-free and accurately annotated physiological data are desirable in patients with brain injury both to inform clinical decision-making and for intelligent analysis of the data in applications such as predictive modelling. We have quantified the quality of annotation surrounding artefactual events and propose a factorial switching linear dynamical systems (FSLDS) approach to automatically detect artefact in physiological data collected in the neurological intensive care unit (NICU). Retrospective analysis of the BrainIT data set to discover potential hypotensive events corrupted by artefact and identify the annotation of associated clinical interventions. Training of an FSLDS model on clinician-annotated artefactual events in five patients with severe traumatic brain injury. In a subset of 187 patients in the BrainIT database, 26.5 % of potential hypotensive events were abandoned because of artefactual data. Only 30 % of these episodes could be attributed to an annotated clinical intervention. As assessed by the area under the receiver operating characteristic curve metric, FSLDS model performance in automatically identifying the events of blood sampling, arterial line damping and patient handling was 0.978, 0.987 and 0.765, respectively. The influence of artefact on physiological data collected in the NICU is a significant problem. This pilot study using an FSLDS approach shows real promise and is under further development.

21 CFR 1308.26 - Excluded veterinary anabolic steroid implant products.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Excluded veterinary anabolic steroid implant... SCHEDULES OF CONTROLLED SUBSTANCES Excluded Veterinary Anabolic Steroid Implant Products § 1308.26 Excluded veterinary anabolic steroid implant products. (a) Products containing an anabolic steroid, that are expressly...

Preservation of archaeological artefacts by γ-ray induced polymerization technique

International Nuclear Information System (INIS)

Gueven, O.

1983-01-01

For the preservation and consolidation of archaeological artefacts irradiation of these objects with γ-rays seems to be a very promising method. In situ polymerization of monomers impregnated in the capillaries and cavities of the objects by γ-rays provides a simultaneous sterilization and consolidation effect. In the present work this method of preservation is applied to some XIIth century ceramic findings belonging to Seljuk period found in South-East Anatolia. Monomer impregnation is restricted to the surfaces of the objects. The colored figures and structures which are present but not perceptible on these objects became fully apparent upon polymerizing hydrophilic monomers on their surfaces. Crosslinking of the top polymer layer further provides a permanent protection of the substrate material. (author)

Towards a Knowledge Communication Perspective on Designing Artefacts Supporting Knowledge Work

Directory of Open Access Journals (Sweden)

Niclas Eberhagen

2015-02-01

Full Text Available The designing of computer-based artefacts to support knowledge work is far from a straightforward rational process. Characteristics of knowledge work have a bearing upon how developers (or designers, together with users, come to approach and capture the rich and tacit knowing of the practice. As all knowledge work is about the production of knowledge, transforming it, so is the design practice for developing artefacts to occupy space within that same practice. There is a need for providing a conceptual language to better reflect the nature of this design work that goes beyond those dressed in the managerial (or rational language of planned activities and deliverables. Towards this end, a conceptual frame is presented that makes several important aspects of the design practice visible. The frame brings together both nature of design work and characteristics of knowledge work to extend the frame of knowledge in user-developer communication of Kensing and Munk-Madsen. Thereby, providing a means to focus attention and dress debate on what situated designing is. By using explicit concepts, such as types knowledge domains embedded in the design situation, the transitional paths between them, and design engagements, it arms practitioners with specific linguistic constructs to direct attention and efforts in planning and organizing development undertakings.Purpose – the purpose of this work is to present and argue for a perspective on designing of computer-based artefacts supporting knowledge work. This is done to inform practitioners, directing their attention and dressing debate, and providing a conceptual language to better capture design activities in planning and organizing development undertakings.Design/Methodology/Approach – The approach presented in this article is conceptual in so far that a model or frame providing linguistic constructs is constructed and argued, building upon scholarly work of knowledge communication and drawing upon

Hyoscine butylbromide significantly decreases motion artefacts and allows better delineation of anatomic structures in mp-MRI of the prostate

Energy Technology Data Exchange (ETDEWEB)

Ullrich, T.; Quentin, M.; Schmaltz, A.K.; Rubbert, C.; Blondin, D.; Antoch, G.; Schimmoeller, L. [University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf (Germany); Arsov, C.; Rabenalt, R.; Albers, P. [University Dusseldorf, Medical Faculty, Department of Urology, Dusseldorf (Germany)

2018-01-15

To prospectively evaluate the effect of hyoscine butylbromide (HBB) on visualisation of anatomical details and motion-related artefacts in mp-MRI of the prostate at 3.0 Tesla. One hundred and three consecutive patients (65 ± 10 years) were included in this trial, powered to demonstrate an improvement of image quality after HBB administration, assessed on a 5-point scale by two blinded readers. All patients received high-spatial resolution axial T2-weighted TSE sequences at 3.0 T without spasmolytic agent, repeated after application of 40 mg HBB and followed by routine mp-MRI. Secondary endpoints were (1) susceptibility to side effects, (2) dependence of spasmolytic effect on patients and acute; weight, and (3) prostate volume. In 68% of patients, HBB significantly improved the anatomic score (mean 3.4 ± 0.9 before and 4.4 ± 0.7 after HBB for both readers, p = <0.001). In 67%, HBB significantly enhanced the artefact score (mean 3.2 ± 1 before and 4.2 ± 0.8 after HBB for reader 1, p = <0.001; 3.2 ± 1 and 4.1 ± 0.8 for reader 2, p = <0.001). Subgroup analysis revealed no statistically significant difference between patients with different bodyweight or prostate volume. Inter-reader agreement was excellent (k = 0.95-0.98). Hyoscine butylbromide significantly improves image quality and reduces motion-related artefacts in mp-MRI of the prostate independent of bodyweight or prostate volume. No side effects were reported. (orig.)

Hyoscine butylbromide significantly decreases motion artefacts and allows better delineation of anatomic structures in mp-MRI of the prostate

International Nuclear Information System (INIS)

Ullrich, T.; Quentin, M.; Schmaltz, A.K.; Rubbert, C.; Blondin, D.; Antoch, G.; Schimmoeller, L.; Arsov, C.; Rabenalt, R.; Albers, P.

2018-01-01

To prospectively evaluate the effect of hyoscine butylbromide (HBB) on visualisation of anatomical details and motion-related artefacts in mp-MRI of the prostate at 3.0 Tesla. One hundred and three consecutive patients (65 ± 10 years) were included in this trial, powered to demonstrate an improvement of image quality after HBB administration, assessed on a 5-point scale by two blinded readers. All patients received high-spatial resolution axial T2-weighted TSE sequences at 3.0 T without spasmolytic agent, repeated after application of 40 mg HBB and followed by routine mp-MRI. Secondary endpoints were (1) susceptibility to side effects, (2) dependence of spasmolytic effect on patients and acute; weight, and (3) prostate volume. In 68% of patients, HBB significantly improved the anatomic score (mean 3.4 ± 0.9 before and 4.4 ± 0.7 after HBB for both readers, p = <0.001). In 67%, HBB significantly enhanced the artefact score (mean 3.2 ± 1 before and 4.2 ± 0.8 after HBB for reader 1, p = <0.001; 3.2 ± 1 and 4.1 ± 0.8 for reader 2, p = <0.001). Subgroup analysis revealed no statistically significant difference between patients with different bodyweight or prostate volume. Inter-reader agreement was excellent (k = 0.95-0.98). Hyoscine butylbromide significantly improves image quality and reduces motion-related artefacts in mp-MRI of the prostate independent of bodyweight or prostate volume. No side effects were reported. (orig.)

Imaging of fullerene-like structures in CNx thin films by electron microscopy; sample preparation artefacts due to ion-beam milling

International Nuclear Information System (INIS)

Czigany, Zs.; Neidhardt, J.; Brunell, I.F.; Hultman, L.

2003-01-01

The microstructure of CN x thin films, deposited by reactive magnetron sputtering, was investigated by transmission electron microscopy (TEM) at 200 kV in plan-view and cross-sectional samples. Imaging artefacts arise in high-resolution TEM due to overlap of nm-sized fullerene-like features for specimen thickness above 5 nm. The thinnest and apparently artefact-free areas were obtained at the fracture edges of plan-view specimens floated-off from NaCl substrates. Cross-sectional samples were prepared by ion-beam milling at low energy to minimize sample preparation artefacts. The depth of the ion-bombardment-induced surface amorphization was determined by TEM cross sections of ion-milled fullerene-like CN x surfaces. The thickness of the damaged surface layer at 5 deg. grazing incidence was 13 and 10 nm at 3 and 0.8 keV, respectively, which is approximately three times larger than that observed on Si prepared under the same conditions. The shallowest damage depth, observed for 0.25 keV, was less than 1 nm. Chemical changes due to N loss and graphitization were also observed by X-ray photoelectron spectroscopy. As a consequence of chemical effects, sputtering rates of CN x films were similar to that of Si, which enables relatively fast ion-milling procedure compared to carbon compounds. No electron beam damage of fullerene-like CN x was observed at 200 kV

Gravel size matters: Early Middle Palaeolithic artefacts made from local Rhine and Meuse deposits in the central Netherlands

NARCIS (Netherlands)

van den Biggelaar, D.F.A.M.; van Balen, R.T.; Kluiving, S.J.; Verpoorte, A.; Alink, A

2016-01-01

The artefact size of the Early Middle Palaeolithic (EMP) assemblages in ice-pushed Rhine–Meuse deposits in the central Netherlands decreases northwestward. This trend correlates to the downstream fining direction of the Rhine–Meuse fluvial system, the source of the rock material, showing that

The usefulness of ultrasound colour-Doppler twinkling artefact for detecting urolithiasis compared with low dose nonenhanced computerized tomography

DEFF Research Database (Denmark)

Winkel, Rikke Rass; Kalhauge, Anna; Fredfeldt, Knud-Erik

2012-01-01

This prospective study evaluates the usefulness of the twinkling artefact (TA) seen on colour-Doppler ultrasound (US) in diagnosing urolithiasis. US and standard computed tomography (CT) were performed blinded on 105 patients. B-mode US and colour-Doppler used separately and in combination showed...

A portable system for acquiring and removing motion artefact from ECG signals

Science.gov (United States)

Griffiths, A.; Das, A.; Fernandes, B.; Gaydecki, P.

2007-07-01

A novel electrocardiograph (ECG) signal acquisition and display system is under development. It is designed for patients ranging from the elderly to athletes. The signals are obtained from electrodes integrated into a vest, amplified, digitally processed and transmitted via Bluetooth to a PC with a Labview ® interface. Digital signal processing is performed to remove movement artefact and electromyographic (EMG) noise, which severely distorts signal morphology and complicates clinical diagnosis. Independent component analysis (ICA) is also used to improve the signal quality. The complete system will integrate the electronics into a single module which will be embedded in the vest.

A portable system for acquiring and removing motion artefact from ECG signals

Energy Technology Data Exchange (ETDEWEB)

Griffiths, A; Das, A; Fernandes, B; Gaydecki, P [School of Electrical and Electronic Engineering, University of Manchester, PO Box 88, Manchester M60 1QD (United Kingdom)

2007-07-15

A novel electrocardiograph (ECG) signal acquisition and display system is under development. It is designed for patients ranging from the elderly to athletes. The signals are obtained from electrodes integrated into a vest, amplified, digitally processed and transmitted via Bluetooth to a PC with a Labview (registered) interface. Digital signal processing is performed to remove movement artefact and electromyographic (EMG) noise, which severely distorts signal morphology and complicates clinical diagnosis. Independent component analysis (ICA) is also used to improve the signal quality. The complete system will integrate the electronics into a single module which will be embedded in the ves000.

Interior lives : the age and interpretation of perishable artefacts from Maori rockshelter sites in inland Otago, New Zealand

International Nuclear Information System (INIS)

Anderson, A.; White, M.; Petchey, F.

2015-01-01

Rockshelter and similar sites in inland Otago have produced a relatively large number of M?ori artefacts made in readily perishable materials such as flax leaves and fibre, tussock grass or tapa (bark) cloth. Regional preservation is clearly related broadly to the relatively arid climate. However, AMS radiocarbon dates on 11 samples from 10 sites shows that while a few date to the 17th century or earlier, the ages of most cluster in the 18th to early 19th centuries. We argue that this represents a phase of accelerated deposition in which material was left behind deliberately, as logistically-determined storage for future use in a strategic plan for exploiting inland resources. We propose that such a process of 'furnishing the landscape' with useful artefacts and stored raw materials became possible when territorial security was achieved by the extension of immigrant tribal authority over the inland region. (author).

Xylem resistance to embolism: presenting a simple diagnostic test for the open vessel artefact.

Science.gov (United States)

Torres-Ruiz, José M; Cochard, Hervé; Choat, Brendan; Jansen, Steven; López, Rosana; Tomášková, Ivana; Padilla-Díaz, Carmen M; Badel, Eric; Burlett, Regis; King, Andrew; Lenoir, Nicolas; Martin-StPaul, Nicolas K; Delzon, Sylvain

2017-07-01

Xylem vulnerability to embolism represents an essential trait for the evaluation of the impact of hydraulics in plant function and ecology. The standard centrifuge technique is widely used for the construction of vulnerability curves, although its accuracy when applied to species with long vessels remains under debate. We developed a simple diagnostic test to determine whether the open-vessel artefact influences centrifuge estimates of embolism resistance. Xylem samples from three species with differing vessel lengths were exposed to less negative xylem pressures via centrifugation than the minimum pressure the sample had previously experienced. Additional calibration was obtained from non-invasive measurement of embolism on intact olive plants by X-ray microtomography. Results showed artefactual decreases in hydraulic conductance (k) for samples with open vessels when exposed to a less negative xylem pressure than the minimum pressure they had previously experienced. X-Ray microtomography indicated that most of the embolism formation in olive occurs at xylem pressures below -4.0 MPa, reaching 50% loss of hydraulic conductivity at -5.3 MPa. The artefactual reductions in k induced by centrifugation underestimate embolism resistance data of species with long vessels. A simple test is suggested to avoid this open vessel artefact and to ensure the reliability of this technique in future studies. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Unicompartmental knee arthroplasty MRI: impact of slice-encoding for metal artefact correction MRI on image quality, findings and therapy decision

International Nuclear Information System (INIS)

Agten, Christoph A.; Pfirrmann, Christian W.A.; Sutter, Reto; Grande, Filippo del; Fucentese, Sandro F.; Blatter, Samuel

2015-01-01

To evaluate the impact of slice-encoding for metal artefact correction (SEMAC) on image quality, findings, and therapy decision in patients with unicompartmental knee arthroplasty (UKA). Forty-five painful UKAs were examined at 1.5T-MRI (STIR, proton-density(PD)-weighted sequence, each with SEMAC and high-bandwidth). Artefact size, image quality, anatomic depiction, and clinically relevant findings were compared between SEMAC and high-bandwidth (2 readers). In 30 patients, therapy decision was retrospectively assessed by two orthopaedic surgeons without MRI, with high-bandwidth-MRI, and with SEMAC-MRI. SEMAC reduced mean artefact size for STIR (11.8 cm 2 vs. 37.7 cm 2 ) and PD (16.8 cm 2 vs. 18.9 cm 2 ), p < 0.0005 for both comparisons. SEMAC showed more blurring than high-bandwidth, p < 0.0005. STIR-SEMAC revealed more bone marrow oedema (29 vs. 18 patients, p = 0.001, 30 vs. 13 patients, p < 0.0005, for reader 1 and 2 respectively). PD-SEMAC was worse in detecting meniscal lesions (6 missed, p = 0.031, 9 missed, p = 0.004, by reader 1 and 2 respectively) than PD-high-bandwidth. Revision-surgery was chosen in 12 and 11 patients without MRI (surgeon 1 and 2), with high-bandwidth-MRI in 15 and 14 patients, and with SEMAC-MRI in 19 and 14 patients. STIR-SEMAC was useful in detecting bone marrow oedema and influenced the orthopaedic surgeons' decisions towards surgery, while PD-SEMAC showed no clinical benefit. (orig.)

The role of movies in Norwegiantextbooks. : A study of film as artefact in religious education.

OpenAIRE

Vestøl, Jon Magne

2012-01-01

Drawing on perspectives on educational design, this article investigates the role of movies in Norwegian secondary school textbooks on religious education, including teachers’ handbooks and textbook websites. All passages containing references to films or movies have been included in the analysis. The distribution of references indicates that a film is an optional artefact and that movies are drawn mainly from a Western cinematic tradition and are related to topics such as Christianity and et...

48 CFR 733.103-73 - Protests excluded from consideration.

Science.gov (United States)

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Protests excluded from consideration. 733.103-73 Section 733.103-73 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL... excluded from consideration. (a) Contract administration. Disputes between a contractor and USAID are...

Anatomical studies of timber and EPMA analysis of brass artefacts collected from steam engine shipwreck of Minicoy Island, Lakshadweep, India

Digital Repository Service at National Institute of Oceanography (India)

Tripati, S.; Shukla, S.R.; Som, V.; Sundaresh; Khedekar, V.; Shashikala, S.; Sharma, S.K.

construction but also for anchors. During exploration of shipwreck off Minicoy doorframe hinge, latch, porthole, flanges, J hook were found and all these artefacts are made of brass. Moreover timber remains noticed on doorframe hinge and latch. In order...

Urethrotonography - a radiological and manometrical combination technique to diagnose urinary stress incontinance in comparison with urethral pressure profile recording

International Nuclear Information System (INIS)

Wess, H.

1982-01-01

The study described here was carried out in order to gain more insight into the pathogenesis of urinary stress incontinance and the related urethrovesical functions. The pathophysiological changes in the urogenital tract that are associated with urinary stress incontinance are described just as well as the clinical symptoms and signs differentiating the individual forms of incontinance from each other. Account is further taken of the various manometrical and radiological techniques used in the diagnosis of urinary stress incontinance. In this study, which included a total of 100 patients, comparative evaluations were made of the pressure behaviour of the bladder during the filling-up phase and the closing mechanism of the urethra both at rest and under stress using the following procedures: - Method developed by Brown and Wickham for urethral pressure profile recording; visualisation of the bladder and urethra with the aid of X-rays and a balloon catheter especially developed by us. The latter technique may help to solve the problems usually arising when given morphological factors are to be connected with certain medical views or theories concerning the vesical and urethral functions as well as the pathogenesis of urinary stress incontinance. It may thus enable more straightforward diagnosis to be made. (TRV) [de

Determination of the length and position of the lower oesophageal sphincter (LOS) by correlation of external measurements with combined radiographic and manometric estimations in the cat

International Nuclear Information System (INIS)

Hashim, M.A.; Waterman, A.E.

1992-01-01

Fifty DSH cats were studied radiographically and a highly significant linear correlation was found between the length of the oesophagus measured to the diaphragmatic line on the radiographs and the externally measured distance from the lower jaw incisor teeth to the anterior border of the head of 10th rib. A subsequent manometric study utilizing this correlation in 40 cats suggests that the functional lower oesophageal sphincter (LOS) is situated almost at the level of the diaphragm in the cat. Significant differences were found between the length of the LOS in cats anaesthetized with ketamine compared to alphaxalone-alphadolone or xylazine-ketamine-atropine. The mean lengths of the LOS was 1.42 +/- 0.3 cm. The findings of this study indicate that external measurements can be used to position catheters for accurate oesophageal manometry in the cat

FT-Raman and FT-Infrared investigations of archaeological artefacts from Foeni Neolithic site (Banat, Romania)

OpenAIRE

Simona Cîntă Pînzaru; Dana Pop; Loredana Nemeth

2008-01-01

An impressive collection of chert artefacts from the Foeni Neolithic archaeological site (Timiş County, Banat region, Romania) is hosted by the Banat Museum in Timişoara. A representative set of seven specimens was non-destructively investigated using FT-Raman and ATR-FT-IR spectroscopy. The research was carried out for checking if these readily-available, non-destructive, fast, and cheap methods, which do not require preliminary sample preparation could provide significant information for ch...

Usefulness of IDEAL T2 imaging for homogeneous fat suppression and reducing susceptibility artefacts in brachial plexus MRI at 3.0 T.

Science.gov (United States)

Tagliafico, Alberto; Bignotti, Bianca; Tagliafico, Giulio; Martinoli, Carlo

2016-01-01

To quantitatively and qualitatively compare fat-suppressed MR imaging quality using iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) with that using frequency-selective fat-suppressed (FSFS) T2 images of the brachial plexus at 3.0 T. Prospective MR image analysis was performed in 40 volunteers and 40 patients at a single centre. Oblique-sagittal and coronal IDEAL fat-suppressed T2 images and FSFS T2 images were compared. Visual assessment was performed by two independent musculoskeletal radiologists with respect to: (1) susceptibility artefacts around the neck, (2) homogeneity of fat suppression, (3) image sharpness and (4) tissue resolution contrast of pathologies. The signal-to-noise ratios (SNR) for each image sequence were assessed. Compared to FSFS sequences, IDEAL fat-suppressed T2 images significantly reduced artefacts around the brachial plexus and significantly improved homogeneous fat suppression (p < 0.05). IDEAL significantly improved sharpness and lesion-to-tissue contrast (p < 0.05). The mean SNRs were significantly improved on T2-weighted IDEAL images (p < 0.05). IDEAL technique improved image quality by reducing artefacts around the brachial plexus while maintaining a high SNR and provided superior homogeneous fat suppression than FSFS sequences.

Modelo experimental de fundoplicatura gastroesofágica em ratos: estudo manométrico e histológico do esôfago Experimental model of gastric-esophageal fundoplication in rats: manometric and histological study of the esophagus

Directory of Open Access Journals (Sweden)

Sérgio Luis Rocha

2004-04-01

Full Text Available OBJETIVO: O presente estudo objetiva avaliar alguns aspectos decorrentes da fundoplicatura em ratos, com técnica de Nissen, através da análise histológica do esôfago distal e estudo manométrico do esfíncter esofágico inferior (EEI, bem como da avaliação da variação do peso dos ratos submetidos ao procedimento, com diferentes dias de evolução. MÉTODOS: Utilizaram-se 70 ratos Wistar, machos, com idade entre 100 e 130 dias e peso entre 250 e 300 g, divididos em dois grupos. O grupo experimento foi composto por 60 ratos, subdivididos em 6 subgrupos de acordo com o tempo de aferição manométrica pós-operatória: 02, 07, 14, 21, 28 e 40 dias, e submetido a fundoplicatura com posterior análise manométrica do EEI e histológica do esôfago distal. O grupo controle foi composto pelos 10 animais restantes, submetido apenas a laparotomia com manipulação da região es��fago-gástrica, e realizaram-se as mesmas análises. RESULTADOS: Evidenciou-se na análise histológica, edema estatisticamente significativo (p=0,0000 nos subgrupos 02 e 07 dias, acompanhado de perda de peso. Observou-se significância estatística no estudo manométrico em todos os subgrupos comparados ao controle (p t c=+2,132. CONCLUSÃO: Após fundoplicatura de Nissen em ratos, a pressão no EEI não retorna aos níveis do controle até o 40º pós-operatório. O edema correlacionado à perda de peso e ao aumento da pressão no EEI pode ser a principal variável relacionada à possível disfagia.PURPOSE: The aim of this experimental study is to evaluate the outcomes of having Nissen fundoplication done on rats through the histological analysis of the distal esophagus and manometric study of the lower esophageal sphincter (LES, as well as the evaluation of weight variation of the rats subjected to this procedure, in distinct days after surgery. METHODS: Have been used 70 male Wistar rats, at the ages of 100 to 130 days , weighing from 250 to 300 grams and divided

Esofagitis eosinofílica en el adulto: aspectos clínicos, endoscópicos, pH-métricos y manométricos Eosinophilic esophagitis in the adult: clinical, endoscopic, pH-metric, and manometric findings

Directory of Open Access Journals (Sweden)

L. Martín Martín

2008-08-01

Full Text Available Objetivos: la esofagitis eosinofílica (EE es una entidad de interés creciente caracterizada en el adulto por disfagia y episodios de impactación alimentaria recurrentes. Nuestro objetivo fue estudiar las características clínicas, endoscópicas, manométricas y pH-métricas en los pacientes con EE, así como la relación que pudiera existir entre ellas. Pacientes y métodos: se estudiaron de forma prospectiva durante un año los pacientes adultos diagnosticados de EE. En todos se realizó endoscopia digestiva alta con toma de biopsias, manometría esofágica estacionaria y pH-metría ambulatoria. Se documentó además el tiempo de evolución clínica, los antecedentes de atopia, la presencia de eosinofilia periférica, la frecuencia de la disfagia y el número de desimpactaciones y complicaciones endoscópicas. Resultados: se estudiaron 11 pacientes (edad media 35 años. Todas las endoscopias presentaron hallazgos patológicos: traquealización en 5, alteraciones mucosas en 4, en 3 anillos esofágicos distales y en 2 estenosis esofágicas. Precisaron desimpactaciones endoscópicas 7 pacientes. Se produjeron desgarros de la mucosa esofágica durante la endoscopia en 2 pacientes. La manometría esofágica fue patológica en 6 pacientes, de estos, 5 fueron trastornos de hipomotilidad. La pH-metría fue patológica en 2 casos. Presentaron eosinofilia periférica 3 pacientes. Conclusión: aunque los hallazgos patológicos en la endoscopia son frecuentes, no siempre justifican los episodios de impactación alimentaria característicos de la EE. Los trastornos de motilidad en forma de peristalsis esofágica ineficaz son el hallazgo manométrico más frecuente, aunque tampoco se han podido relacionar con un mayor número de episodios de disfagia o de impactaciones.Objectives: eosinophilic esophagitis (EE is a condition characterized by dysphagia and frequent food impaction in young adults. The aim of our study was to evaluate the clinical aspects

Excluded Volume Effects in Gene Stretching

OpenAIRE

Lam, Pui-Man

2002-01-01

We investigate the effects excluded volume on the stretching of a single DNA in solution. We find that for small force F, the extension h is not linear in F but proportion to F^{\\chi}, with \\chi=(1-\

Simultaneous EEG–fMRI: evaluating the effect of the cabling configuration on the gradient artefact

International Nuclear Information System (INIS)

Chowdhury, M E H; Mullinger, Karen J; Bowtell, Richard

2015-01-01

EEG recordings made in combined EEG–fMRI studies are corrupted by gradient artefacts (GAs) resulting from the interaction of the EEG system with the time-varying magnetic field gradients used in MRI. The dominant contribution to the GA arises from interaction with the leads of the EEG cap and the human head, but artefacts are also produced in the cables used to connect the EEG cap to the amplifier. The aim of this study is to measure the effects of the connecting cable configuration on the characteristics of the GA. We measured the GA produced on two different cable configurations (a ribbon cable and a cable consisting of wires that are twisted together to form a cylindrical bundle) by gradient pulses applied on three orthogonal axes and also characterized the effect of each cable configuration on the GA generated by a multi-slice echo planar imaging sequence, as employed in typical EEG–fMRI studies. The results demonstrate that the cabling that connects the EEG cap to the amplifier can make a significant contribution to the GA recorded during EEG–fMRI studies. In particular, we demonstrate that the GA generated by a ribbon cable is larger than that produced using a twisted cable arrangement and that changes in the GA resulting from variation in the cable position are also greater for the ribbon cable. (note)

Simultaneous EEG-fMRI: evaluating the effect of the cabling configuration on the gradient artefact

Science.gov (United States)

Chowdhury, M. E. H.; Mullinger, Karen J.; Bowtell, Richard

2015-06-01

EEG recordings made in combined EEG-fMRI studies are corrupted by gradient artefacts (GAs) resulting from the interaction of the EEG system with the time-varying magnetic field gradients used in MRI. The dominant contribution to the GA arises from interaction with the leads of the EEG cap and the human head, but artefacts are also produced in the cables used to connect the EEG cap to the amplifier. The aim of this study is to measure the effects of the connecting cable configuration on the characteristics of the GA. We measured the GA produced on two different cable configurations (a ribbon cable and a cable consisting of wires that are twisted together to form a cylindrical bundle) by gradient pulses applied on three orthogonal axes and also characterized the effect of each cable configuration on the GA generated by a multi-slice echo planar imaging sequence, as employed in typical EEG-fMRI studies. The results demonstrate that the cabling that connects the EEG cap to the amplifier can make a significant contribution to the GA recorded during EEG-fMRI studies. In particular, we demonstrate that the GA generated by a ribbon cable is larger than that produced using a twisted cable arrangement and that changes in the GA resulting from variation in the cable position are also greater for the ribbon cable.

Looking for the Signal: A guide to iterative noise and artefact removal in X-ray tomographic reconstructions of porous geomaterials

Science.gov (United States)

Bruns, S.; Stipp, S. L. S.; Sørensen, H. O.

2017-07-01

X-ray micro- and nanotomography has evolved into a quantitative analysis tool rather than a mere qualitative visualization technique for the study of porous natural materials. Tomographic reconstructions are subject to noise that has to be handled by image filters prior to quantitative analysis. Typically, denoising filters are designed to handle random noise, such as Gaussian or Poisson noise. In tomographic reconstructions, noise has been projected from Radon space to Euclidean space, i.e. post reconstruction noise cannot be expected to be random but to be correlated. Reconstruction artefacts, such as streak or ring artefacts, aggravate the filtering process so algorithms performing well with random noise are not guaranteed to provide satisfactory results for X-ray tomography reconstructions. With sufficient image resolution, the crystalline origin of most geomaterials results in tomography images of objects that are untextured. We developed a denoising framework for these kinds of samples that combines a noise level estimate with iterative nonlocal means denoising. This allows splitting the denoising task into several weak denoising subtasks where the later filtering steps provide a controlled level of texture removal. We describe a hands-on explanation for the use of this iterative denoising approach and the validity and quality of the image enhancement filter was evaluated in a benchmarking experiment with noise footprints of a varying level of correlation and residual artefacts. They were extracted from real tomography reconstructions. We found that our denoising solutions were superior to other denoising algorithms, over a broad range of contrast-to-noise ratios on artificial piecewise constant signals.

Unicompartmental knee arthroplasty MRI: impact of slice-encoding for metal artefact correction MRI on image quality, findings and therapy decision

Energy Technology Data Exchange (ETDEWEB)

Agten, Christoph A.; Pfirrmann, Christian W.A.; Sutter, Reto [Balgrist University Hospital, Radiology Department, Zurich (Switzerland); University of Zurich, Faculty of Medicine, Zurich (Switzerland); Grande, Filippo del [Regional Hospital, Radiology, Lugano (Switzerland); Fucentese, Sandro F.; Blatter, Samuel [University of Zurich, Faculty of Medicine, Zurich (Switzerland); Balgrist University Hospital, Orthopedics, Zurich (Switzerland)

2015-07-15

To evaluate the impact of slice-encoding for metal artefact correction (SEMAC) on image quality, findings, and therapy decision in patients with unicompartmental knee arthroplasty (UKA). Forty-five painful UKAs were examined at 1.5T-MRI (STIR, proton-density(PD)-weighted sequence, each with SEMAC and high-bandwidth). Artefact size, image quality, anatomic depiction, and clinically relevant findings were compared between SEMAC and high-bandwidth (2 readers). In 30 patients, therapy decision was retrospectively assessed by two orthopaedic surgeons without MRI, with high-bandwidth-MRI, and with SEMAC-MRI. SEMAC reduced mean artefact size for STIR (11.8 cm{sup 2} vs. 37.7 cm{sup 2}) and PD (16.8 cm{sup 2} vs. 18.9 cm{sup 2}), p < 0.0005 for both comparisons. SEMAC showed more blurring than high-bandwidth, p < 0.0005. STIR-SEMAC revealed more bone marrow oedema (29 vs. 18 patients, p = 0.001, 30 vs. 13 patients, p < 0.0005, for reader 1 and 2 respectively). PD-SEMAC was worse in detecting meniscal lesions (6 missed, p = 0.031, 9 missed, p = 0.004, by reader 1 and 2 respectively) than PD-high-bandwidth. Revision-surgery was chosen in 12 and 11 patients without MRI (surgeon 1 and 2), with high-bandwidth-MRI in 15 and 14 patients, and with SEMAC-MRI in 19 and 14 patients. STIR-SEMAC was useful in detecting bone marrow oedema and influenced the orthopaedic surgeons' decisions towards surgery, while PD-SEMAC showed no clinical benefit. (orig.)

Excluded segmental duct bile leakage: the case for bilio-enteric anastomosis.

Science.gov (United States)

Patrono, Damiano; Tandoi, Francesco; Romagnoli, Renato; Salizzoni, Mauro

2014-06-01

Excluded segmental duct bile leak is the rarest type of post-hepatectomy bile leak and presents unique diagnostic and management features. Classical management strategies invariably entail a significant loss of functioning hepatic parenchyma. The aim of this study is to report a new liver-sparing technique to handle excluded segmental duct bile leakage. Two cases of excluded segmental duct bile leak occurring after major hepatic resection were managed by a Roux-en-Y hepatico-jejunostomy on the excluded segmental duct, avoiding the sacrifice of the liver parenchyma origin of the fistula. In both cases, classical management strategies would have led to the functional loss of roughly 50 % of the liver remnant. Diagnostic and management implications are thoroughly discussed. Both cases had an uneventful postoperative course. The timing of repair was associated with a different outcome: the patient who underwent surgical repair in the acute phase developed no long-term complications, whereas the patient who underwent delayed repair developed a late stenosis requiring percutaneous dilatation. Roux-en-Y hepatico-jejunostomy on the excluded bile duct is a valuable technique in selected cases of excluded segmental duct bile leakage.

Quantifying metal artefact reduction using virtual monochromatic dual-layer detector spectral CT imaging in unilateral and bilateral total hip prostheses

NARCIS (Netherlands)

Wellenberg, R. H. H.; Boomsma, M. F.; van Osch, J. A. C.; Vlassenbroek, A.; Milles, J.; Edens, M. A.; Streekstra, G. J.; Slump, C. H.; Maas, M.

2017-01-01

To quantify the impact of prosthesis material and design on the reduction of metal artefacts in total hip arthroplasties using virtual monochromatic dual-layer detector Spectral CT imaging. The water-filled total hip arthroplasty phantom was scanned on a novel 128-slice Philips IQon dual-layer

The Value of the Right to Exclude: An Empirical Assessment

NARCIS (Netherlands)

J.M. Klick (Jonathan); G. Parchomovsky (Gideon)

2016-01-01

markdownabstractProperty theorists have long deemed the right to exclude fundamental and essential for the efficient use and allocation of property. Recently, however, proponents of the progressive property movement have called into question the centrality of the right to exclude, suggesting that it

Application of a Portable XRF Spectrometer for the Non-Invasive analysis of Museum Metal Artefacts

International Nuclear Information System (INIS)

Karydas, A.G.

2007-01-01

The present paper reviews examples of the application of a portable - in house developed- X RF spectrometer for the analysis of museum metal artefacts in Greece. Specific topics are addressed, in particular, to which extent the qualitative or quantitative X RF analyses reveal important information about the raw materials and manufacture techniques used for gold, silver and bronze alloys in antiquity. The analytical information that it is gained by means of the X RF measurements is further assessed in comparison with the existing archaeometallurgical knowledge

Reducing beam hardening effects and metal artefacts using Medipix3RX: With applications from biomaterial science

OpenAIRE

Rajendran, K.; Walsh, M. F.; de Ruiter, N. J. A.; Chernoglazov, A. I.; Panta, R. K.; Butler, A. P. H.; Butler, P. H.; Bell, S. T.; Anderson, N. G.; Woodfield, T. B. F.; Tredinnick, S. J.; Healy, J. L.; Bateman, C. J.; Aamir, R.; Doesburg, R. M. N.

2013-01-01

This paper discusses methods for reducing beam hardening effects using spectral data for biomaterial applications. A small-animal spectral scanner operating in the diagnostic energy range was used. We investigate the use of photon-processing features of the Medipix3RX ASIC in reducing beam hardening and associated artefacts. A fully operational charge summing mode was used during the imaging routine. We present spectral data collected for metal alloy samples, its analysis using algebraic 3D r...

Excluding joint probabilities from quantum theory

Science.gov (United States)

Allahverdyan, Armen E.; Danageozian, Arshag

2018-03-01

Quantum theory does not provide a unique definition for the joint probability of two noncommuting observables, which is the next important question after the Born's probability for a single observable. Instead, various definitions were suggested, e.g., via quasiprobabilities or via hidden-variable theories. After reviewing open issues of the joint probability, we relate it to quantum imprecise probabilities, which are noncontextual and are consistent with all constraints expected from a quantum probability. We study two noncommuting observables in a two-dimensional Hilbert space and show that there is no precise joint probability that applies for any quantum state and is consistent with imprecise probabilities. This contrasts with theorems by Bell and Kochen-Specker that exclude joint probabilities for more than two noncommuting observables, in Hilbert space with dimension larger than two. If measurement contexts are included into the definition, joint probabilities are not excluded anymore, but they are still constrained by imprecise probabilities.

8 CFR 241.21 - Stay of deportation of excluded alien.

Science.gov (United States)

2010-01-01

... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Stay of deportation of excluded alien. 241.21 Section 241.21 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS APPREHENSION AND DETENTION OF ALIENS ORDERED REMOVED Deportation of Excluded Aliens (for Hearings Commenced...

The fission-track analysis: An alternative technique for provenance studies of prehistoric obsidian artefacts

CERN Document Server

Bellot-Gurlet, L; Dorighel, O; Oddone, M; Poupeau, G; Yegingil, Z

1999-01-01

Comparison of fission-track parameters - age and track densities - is an alternative tool for correlating obsidian artefacts with their potential natural sources. This method was applied by different fission-track groups in various regions and results were compared with those obtained using the more popular provenance identification techniques based on chemical composition studies. Hundreds of analyses prove that fission-track dating is a complementary technique which turns out to be very useful, specially when the chemical composition does not fully discriminate different sources. Archaeologically significant results were obtained applying the fission-track analysis in various regions of earth.

The fission-track analysis: An alternative technique for provenance studies of prehistoric obsidian artefacts

International Nuclear Information System (INIS)

Bellot-Gurlet, L.; Bigazzi, G.; Dorighel, O.; Oddone, M.; Poupeau, G.; Yegingil, Z.

1999-01-01

Comparison of fission-track parameters - age and track densities - is an alternative tool for correlating obsidian artefacts with their potential natural sources. This method was applied by different fission-track groups in various regions and results were compared with those obtained using the more popular provenance identification techniques based on chemical composition studies. Hundreds of analyses prove that fission-track dating is a complementary technique which turns out to be very useful, specially when the chemical composition does not fully discriminate different sources. Archaeologically significant results were obtained applying the fission-track analysis in various regions of earth

How could the Viking Sun compass be used with sunstones before and after sunset? Twilight board as a new interpretation of the Uunartoq artefact fragment.

Science.gov (United States)

Bernáth, Balázs; Farkas, Alexandra; Száz, Dénes; Blahó, Miklós; Egri, Adám; Barta, András; Akesson, Susanne; Horváth, Gábor

2014-06-08

Vikings routinely crossed the North Atlantic without a magnetic compass and left their mark on lands as far away as Greenland, Newfoundland and Baffin Island. Based on an eleventh-century dial fragment artefact, found at Uunartoq in Greenland, it is widely accepted that they sailed along chosen latitudes using primitive Sun compasses. Such instruments were tested on sea and proved to be efficient hand-held navigation tools, but the dimensions and incisions of the Uunartoq find are far from optimal in this role. On the basis of the sagas mentioning sunstones, incompatible hypotheses were formed for Viking solar navigation procedures and primitive skylight polarimetry with dichroic or birefringent crystals. We describe here a previously unconceived method of navigation based on the Uunartoq artefact functioning as a 'twilight board', which is a combination of a horizon board and a Sun compass optimized for use when the Sun is close to the horizon. We deduced an appropriate solar navigation procedure using a twilight board, a shadow-stick and birefringent crystals, which bring together earlier suggested methods in harmony and provide a true skylight compass function. This could have allowed Vikings to navigate around the clock, to use the artefact dial as a Sun compass during long parts of the day and to use skylight polarization patterns in the twilight period. In field tests, we found that true north could be appointed with such a medieval skylight compass with an error of about ±4° when the artificially occluded Sun had elevation angles between +10° and -8° relative to the horizon. Our interpretation allows us to assign exact dates to the gnomonic lines on the artefact and outlines the schedule of the merchant ships that sustained the Viking colony in Greenland a millennium ago.

Is metal artefact reduction mandatory in cardiac PET/CT imaging in the presence of pacemaker and implantable cardioverter defibrillator leads?

Energy Technology Data Exchange (ETDEWEB)

Ghafarian, Pardis [Shahid Beheshti University, Department of Radiation Medicine, Tehran (Iran, Islamic Republic of); Geneva University Hospital, Division of Nuclear Medicine, Geneva 4 (Switzerland); Tehran University of Medical Sciences, Research Center for Science and Technology in Medicine, Tehran (Iran, Islamic Republic of); Aghamiri, S.M.R. [Shahid Beheshti University, Department of Radiation Medicine, Tehran (Iran, Islamic Republic of); Ay, Mohammad R. [Tehran University of Medical Sciences, Research Center for Science and Technology in Medicine, Tehran (Iran, Islamic Republic of); Tehran University of Medical Sciences, Department of Medical Physics and Biomedical Engineering, Tehran (Iran, Islamic Republic of); Tehran University of Medical Sciences, Research Institute for Nuclear Medicine, Tehran (Iran, Islamic Republic of); Rahmim, Arman [Johns Hopkins University, Department of Radiology, Baltimore, MD (United States); Schindler, Thomas H. [Geneva University, Cardiovascular Center, Nuclear Cardiology, Geneva (Switzerland); Ratib, Osman [Geneva University Hospital, Division of Nuclear Medicine, Geneva 4 (Switzerland); Zaidi, Habib [Geneva University Hospital, Division of Nuclear Medicine, Geneva 4 (Switzerland); Geneva University, Geneva Neuroscience Center, Geneva (Switzerland)

2011-02-15

Cardiac PET/CT imaging is often performed in patients with pacemakers and implantable cardioverter defibrillator (ICD) leads. However, metallic implants usually produce artefacts on CT images which might propagate to CT-based attenuation-corrected (CTAC) PET images. The impact of metal artefact reduction (MAR) for CTAC of cardiac PET/CT images in the presence of pacemaker, ICD and ECG leads was investigated using both qualitative and quantitative analysis in phantom and clinical studies. The study included 14 patients with various leads undergoing perfusion and viability examinations using dedicated cardiac PET/CT protocols. The PET data were corrected for attenuation using both artefactual CT images and CT images corrected using the MAR algorithm. The severity and magnitude of metallic artefacts arising from these leads were assessed on both linear attenuation coefficient maps ({mu}-maps) and attenuation-corrected PET images. CT and PET emission data were obtained using an anthropomorphic thorax phantom and a dedicated heart phantom made in-house incorporating pacemaker and ICD leads attached at the right ventricle of the heart. Volume of interest-based analysis and regression plots were performed for regions related to the lead locations. Bull's eye view analysis was also performed on PET images corrected for attenuation with and without the MAR algorithm. In clinical studies, the visual assessment of PET images by experienced physicians and quantitative analysis did not reveal erroneous interpretation of the tracer distribution or significant differences when PET images were corrected for attenuation with and without MAR. In phantom studies, the mean differences between tracer uptake obtained without and with MAR were 10.16{+-}2.1% and 6.86{+-}2.1% in the segments of the heart in the vicinity of metallic ICD or pacemaker leads, and were 4.43{+-}0.5% and 2.98{+-}0.5% in segments far from the leads. Although the MAR algorithm was able to effectively improve

The characterization of artefacts of cultural heritage significance using physical techniques

International Nuclear Information System (INIS)

Creagh, D.C.

2005-01-01

All societies attempt to preserve their cultural heritage because it is this that gives them their identity. How artefacts are identified as being of significance to society, and how to preserve these for posterity, depend on the sophistication of those societies, their wealth, and the determination of members of the societies to preserve their past. If conservation or restoration measures are being undertaken complex analytical experiments must be undertaken beforehand to ensure that the work is being undertaken in an appropriate manner. These investigations may employ electromagnetic (IR, VIS, UV, X-ray, γ-ray) or particulate (electron, proton, neutron, and ion beams) radiation. The use of many of these techniques is described in this paper in experiments on Australian Aboriginal bark paintings, a suit of armour belonging to a famous Australian outlaw, and the degradation of colour motion picture film

Dynamic miniature lighting system with low correlated colour temperature and high colour rendering index for museum lighting of fragile artefacts

DEFF Research Database (Denmark)

Thorseth, Anders; Corell, Dennis Dan; Poulsen, Peter Behrensdorff

2013-01-01

of historical artefacts in display cases at museums and other exhibitions, which can replace 3-5 Watt incandescent light bulbs with a correlated colour temperature (CCT) from 2000 K to 2400 K. The solution decreases the energy consumption by up to 80 %, while maintaining colour rendering indices (Ra) above 90...

21 CFR 1310.08 - Excluded transactions.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Excluded transactions. 1310.08 Section 1310.08 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE RECORDS AND REPORTS OF LISTED...) Colombia (6) Ecuador (7) French Guiana (8) Guyana (9) Panama (10) Paraguay (11) Peru (12) Suriname (13...

42 CFR 403.768 - Excluded services.

Science.gov (United States)

2010-10-01

... a RNHCI. (c) A nurse who is not providing RNHCI home nursing services under arrangement with a RNHCI... 42 Public Health 2 2010-10-01 2010-10-01 false Excluded services. 403.768 Section 403.768 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL...

22 CFR 40.102 - Guardian required to accompany excluded alien.

Science.gov (United States)

2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Guardian required to accompany excluded alien. 40.102 Section 40.102 Foreign Relations DEPARTMENT OF STATE VISAS REGULATIONS PERTAINING TO BOTH... Guardian required to accompany excluded alien. INA 212(a)(9)(B) is not applicable at the time of visa...

Insular artefacts from Viking-Age burials from mid-Norway. A review of contact between Trøndelag and Britain and Ireland

Directory of Open Access Journals (Sweden)

Aina Margrethe Heen-Pettersen

2014-12-01

Full Text Available This article presents a detailed overview of the Insular artefacts found in Viking-Age burials from the Trøndelag region of mid-Norway, most of which have not previously been published in English. The archaeological evidence indicates that contact between Trøndelag and the British Isles was well established at an early stage of the Viking Age. The main evidence for contact comes from the 9th century, when a number of significant patterns can be discerned. Some local concentrations of Insular goods show the continuing importance of some pre-Viking centres, while other areas suggest co-operation between several neighbouring families in order to equip and provision overseas expeditions. Later, the datable Insular artefacts indicate significant changes in the nature of contact. North Sea trading towards the end of the Viking Age appears to be affected by increasing centralisation of power in Trøndelag during the 10th century.

The social construction of facts and artefacts: or How the sociology of science and the sociology of technology might benefit each other

NARCIS (Netherlands)

Pinch, Trevor J.; Bijker, Wiebe E.

1984-01-01

The need for an integrated social constructivist approach towards the study of science and technology is outlined. Within such a programme both scientific facts and technological artefacts are to be understood as social constructs. Literature on the sociology of science, the science-technology

EVALUATING AND REFINING THE ‘ENTERPRISE ARCHITECTURE AS STRATEGY’ APPROACH AND ARTEFACTS

Directory of Open Access Journals (Sweden)

M. De Vries

2012-01-01

Full Text Available

ENGLISH ABSTRACT: Enterprise Architecture (EA is a new discipline that has emerged from the need to create a holistic view of an enterprise, and thereby to discover business/IT integration and alignment opportunities across enterprise structures. Previous EA value propositions that merely focus on IT cost reductions will no longer convince management to invest in EA. Today, EA should enable business strategy in the organisation to create value. This resides in the ability to do enterprise optimisation through process standardisation and integration. In order to do this, a new approach is required to integrate EA into the strategy planning process of the organisation.
This article explores the use of three key artefacts – operating models, core diagrams, and an operating maturity assessment as defined by Ross, Weill & Robertson [1] – as the basis of this new approach. Action research is applied to a research group to obtain qualitative feedback on the practicality of the artefacts.

AFRIKAANSE OPSOMMING: Ondernemingsargitektuur (OA is ’n nuwe dissipline wat ontstaan het uit die behoefte om ’n holistiese perspektief van ’n onderneming te skep om sodoende besigheid/IT-integrasie en - belyningsgeleenthede regoor ondernemingstrukture te ontdek. Vorige OA waardeaanbiedings wat hoofsaaklik gefokus het op IT kostebesparings sal bestuur nie meer kan oorreed om in OA te belê nie. Vandag behoort OA bevoegdheid te gee aan ondernemingstrategie om werklik waarde te skep. Hierdie bevoegdheid lê gesetel in ondernemingsoptimering deur middel van prosesstandaardisasie en -integrasie. ’n Nuwe benadering word benodig ten einde OA te integreer met die strategiese beplanningsproses van die organisasie.
Hierdie artikel ondersoek die gebruik van drie artefakte – operasionele modelle, kerndiagramme, en operasionele volwassenheidsassessering soos gedefinieer deur Ross, Weill & Robertson [1] – as die basis van hierdie nuwe benadering

Correction of motion artefacts and pseudo colour visualization of multispectral light scattering images for optical diagnosis of rheumatoid arthritis

Science.gov (United States)

Minet, Olaf; Scheibe, Patrick; Beuthan, Jürgen; Zabarylo, Urszula

2010-02-01

State-of-the-art image processing methods offer new possibilities for diagnosing diseases using scattered light. The optical diagnosis of rheumatism is taken as an example to show that the diagnostic sensitivity can be improved using overlapped pseudo-coloured images of different wavelengths, provided that multispectral images are recorded to compensate for any motion related artefacts which occur during examination.

Protection of metal artefacts with the formation of metal-oxalates complexes by Beauveria bassiana.

Directory of Open Access Journals (Sweden)

Edith eJoseph

2012-01-01

Full Text Available Several fungi present high tolerance to toxic metals and some are able to transform metals into metal-oxalate complexes. In this study, the ability of Beauveria bassiana to produce copper oxalates was evaluated in vitro. Growth performance was tested on various copper-containing media. B. bassiana proved highly resistant to copper, tolerating concentrations of up to 20 g.L-1, and precipitating copper oxalates on all media tested. Chromatographic analyses showed that this species produced oxalic acid as sole metal chelator. The production of metal-oxalates can be used in the restoration and conservation of archaeological and modern metal artefacts. The production of copper-oxalates was confirmed directly using metallic pieces (both archaeological and modern. The conversion of corrosion products into copper oxalates was demonstrated as well. In order to assess whether the capability of B. bassiana to produce metal-oxalates could be applied to other metals, iron and silver were tested as well. Iron appears to be directly sequestered in the wall of the fungal hyphae forming oxalates and probably goethite. However, the formation of a homogeneous layer on the object is not yet optimal. Silver nitrate was extracellularly reduced into nanoparticles of elemental silver by an unknown mechanism. The production of copper oxalates is immediately applicable for the conservation of copper-based artefacts. For iron and silver this is not yet the case. However, the vast ability of B. bassiana to transform toxic metals using different immobilization mechanisms seems to offer considerable possibilities for industrial applications, such as the bioremediation of contaminated soils or the green synthesis of chemicals.

26 CFR 31.3402(e)-1 - Included and excluded wages.

Science.gov (United States)

2010-04-01

... 26 Internal Revenue 15 2010-04-01 2010-04-01 false Included and excluded wages. 31.3402(e)-1... SOURCE Collection of Income Tax at Source § 31.3402(e)-1 Included and excluded wages. (a) If a portion of... not more than 31 consecutive days constitutes wages, and the remainder does not constitute wages, all...

A micro-invasive approach using INAA for new insights into Palaeolithic flint archaeological artefacts

International Nuclear Information System (INIS)

Prudencio, M.I.; Dias, M.I.; Marques, R.; Roldan, C.; Aleix Eixea; Villaverde, V.

2016-01-01

Instrumental neutron activation analysis of small flakes from the same flint fragment of archaeological artefacts from Palaeolithic sites ('Abrigo de la Quebrada', 'Cova de les Cendres' and 'Cova Negra'), and eological sour ces (Chelva, Valencia, and Alcoi, Alicante) from the eastern Spain, was performed. The chemical contents of 27 elements were obtained. Ga, Ce, Nd, Yb, Zr and Hf were discarded due to high variations within the same fragment. The identification of chemical fingerprints within heterogeneous flint fragments was able to differentiate flint types and variants ('Domeno' and 'Serreta'), contributing to provenance and human mobility in ancient times. (author)

Quantitative assessment of chemical artefacts produced by propionylation of histones prior to mass spectrometry analysis.

Science.gov (United States)

Soldi, Monica; Cuomo, Alessandro; Bonaldi, Tiziana

2016-07-01

Histone PTMs play a crucial role in regulating chromatin structure and function, with impact on gene expression. MS is nowadays widely applied to study histone PTMs systematically. Because histones are rich in arginine and lysine, classical shot-gun approaches based on trypsin digestion are typically not employed for histone modifications mapping. Instead, different protocols of chemical derivatization of lysines in combination with trypsin have been implemented to obtain "Arg-C like" digestion products that are more suitable for LC-MS/MS analysis. Although widespread, these strategies have been recently described to cause various side reactions that result in chemical modifications prone to be misinterpreted as native histone marks. These artefacts can also interfere with the quantification process, causing errors in histone PTMs profiling. The work of Paternoster V. et al. is a quantitative assessment of methyl-esterification and other side reactions occurring on histones after chemical derivatization of lysines with propionic anhydride [Proteomics 2016, 16, 2059-2063]. The authors estimate the effect of different solvents, incubation times, and pH on the extent of these side reactions. The results collected indicate that the replacement of methanol with isopropanol or ACN not only blocks methyl-esterification, but also significantly reduces other undesired unspecific reactions. Carefully titrating the pH after propionic anhydride addition is another way to keep methyl-esterification under control. Overall, the authors describe a set of experimental conditions that allow reducing the generation of various artefacts during histone propionylation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ross filter pairs for metal artefact reduction in x-ray tomography: a case study based on imaging and segmentation of metallic implants

Science.gov (United States)

Arhatari, Benedicta D.; Abbey, Brian

2018-01-01

Ross filter pairs have recently been demonstrated as a highly effective means of producing quasi-monoenergetic beams from polychromatic X-ray sources. They have found applications in both X-ray spectroscopy and for elemental separation in X-ray computed tomography (XCT). Here we explore whether they could be applied to the problem of metal artefact reduction (MAR) for applications in medical imaging. Metal artefacts are a common problem in X-ray imaging of metal implants embedded in bone and soft tissue. A number of data post-processing approaches to MAR have been proposed in the literature, however these can be time-consuming and sometimes have limited efficacy. Here we describe and demonstrate an alternative approach based on beam conditioning using Ross filter pairs. This approach obviates the need for any complex post-processing of the data and enables MAR and segmentation from the surrounding tissue by exploiting the absorption edge contrast of the implant.

Acting on social exclusion: neural correlates of punishment and forgiveness of excluders.

Science.gov (United States)

Will, Geert-Jan; Crone, Eveline A; Güroğlu, Berna

2015-02-01

This functional magnetic resonance imaging study examined the neural correlates of punishment and forgiveness of initiators of social exclusion (i.e. 'excluders'). Participants divided money in a modified Dictator Game between themselves and people who previously either included or excluded them during a virtual ball-tossing game (Cyberball). Participants selectively punished the excluders by decreasing their outcomes; even when this required participants to give up monetary rewards. Punishment of excluders was associated with increased activation in the pre-supplementary motor area (pre-SMA) and bilateral anterior insula. Costly punishment was accompanied by higher activity in the pre-SMA compared with punishment that resulted in gains or was non-costly. Refraining from punishment (i.e. forgiveness) was associated with self-reported perspective-taking and increased activation in the bilateral temporoparietal junction, dorsomedial prefrontal cortex, dorsal anterior cingulate cortex, and ventrolateral and dorsolateral prefrontal cortex. These findings show that social exclusion can result in punishment as well as forgiveness of excluders and that separable neural networks implicated in social cognition and cognitive control are recruited when people choose either to punish or to forgive those who excluded them. © The Author (2014). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

GUILT OF PERSONS WITH MENTAL DISORDERS ARE NOT EXCLUDING RESPONSIBILITIES

Directory of Open Access Journals (Sweden)

Ekaterina Valerievna Yurchak

2014-10-01

Full Text Available In the theory of law as a key cross-sectoral and multi-disciplinary institutions is the Institute of guilt. At the present stage of development of the law, in a convergence of many of its branches, it is important to investigate exhaustively the institution with the general legal position, both in general and in particular - the situation of the guilt of persons with mental disorder, not excluding sanity.The purpose of this study - to investigate the situation of the fault of persons with a mental disorder, not excluding sanity in different areas of law, and address the question of whether this interdisciplinary institute.Scientific, theoretical and practical significance of the work lies in the fact that the study of this topic will summarize the knowledge about the fault of persons with a mental disorder, not excluding sanity, to analyze the content of this institution in various areas of law, and to conclude that the cross-sectoral character.The author uses formal-legal, comparative, hermeneutical, mathematical methods, as well as general methods of scientific research.The author analyzes the provisions of the Russian legislation on the fault of persons with a mental disorder, not excluding sanity, concluding that the criminal law of guilt people with a mental disorder, not excluding sanity, the most developed and taken into account as a circumstance affecting the punishment. In other areas of the law said institution worked shallow.The results of this study are scientific and practical value, because they can be useful for teaching students - in the industrial discipline "Criminal Law" and the general theoretical discipline "Theory of State and Law"; in science - by picking up information about the features of the Institute of guilt, and in practice - said the work can be useful to practitioners of judicial and investigative bodies, in order to understand the meaning and importance of the category of guilt, including - the guilt of persons

Apneic oxygenation for elimination of respiratory motion artefact in an intubated patient undergoing helical chest computed tomography angiography.

Directory of Open Access Journals (Sweden)

Ioannis Pneumatikos

2008-10-01

Full Text Available Respiratory motion artifact in intubated and mechanically ventilated patients often reduces the quality of helical computed tomography pulmonary angiography (CTPA. Apneic oxygenation is a well established intra-operative technique that allows adequate oxygenation for short periods (up to 10 min in sedated and paralyzed patients. We describe the use of the apneic oxygenation for elimination of respiratory motion artefact in an intubated patient undergoing helical chest computed tomography angiography.

17 CFR 37.4 - Election to trade excluded and exempt commodities.

Science.gov (United States)

2010-04-01

... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Election to trade excluded and exempt commodities. 37.4 Section 37.4 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION DERIVATIVES TRANSACTION EXECUTION FACILITIES § 37.4 Election to trade excluded and exempt...

Metallic artefact reduction with monoenergetic dual-energy CT: systematic ex vivo evaluation of posterior spinal fusion implants from various vendors and different spine levels

Energy Technology Data Exchange (ETDEWEB)

Guggenberger, R.; Winklhofer, S.; Andreisek, G.; Alkadhi, H.; Stolzmann, P. [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Osterhoff, G.; Wanner, G.A. [University Hospital Zurich, Department of Surgery, Division of Trauma Surgery, Zurich (Switzerland); Fortunati, M. [The Spine Center, Thun (Switzerland)

2012-11-15

To evaluate optimal monoenergetic dual-energy computed tomography (DECT) settings for artefact reduction of posterior spinal fusion implants of various vendors and spine levels. Posterior spinal fusion implants of five vendors for cervical, thoracic and lumbar spine were examined ex vivo with single-energy (SE) CT (120 kVp) and DECT (140/100 kVp). Extrapolated monoenergetic DECT images at 64, 69, 88, 105 keV and individually adjusted monoenergy for optimised image quality (OPTkeV) were generated. Two independent radiologists assessed quantitative and qualitative image parameters for each device and spine level. Inter-reader agreements of quantitative and qualitative parameters were high (ICC = 0.81-1.00, {kappa} = 0.54-0.77). HU values of spinal fusion implants were significantly different among vendors (P < 0.001), spine levels (P < 0.01) and among SECT, monoenergetic DECT of 64, 69, 88, 105 keV and OPTkeV (P < 0.01). Image quality was significantly (P < 0.001) different between datasets and improved with higher monoenergies of DECT compared with SECT (V = 0.58, P < 0.001). Artefacts decreased significantly (V = 0.51, P < 0.001) at higher monoenergies. OPTkeV values ranged from 123-141 keV. OPTkeV according to vendor and spine level are presented herein. Monoenergetic DECT provides significantly better image quality and less metallic artefacts from implants than SECT. Use of individual keV values for vendor and spine level is recommended. (orig.)

Our grandmothers, excluded from history, preservers and ...

African Journals Online (AJOL)

Our grandmothers, excluded from history, preservers and transmitters of indegenous values: ecomaternalistic approach. ... Journal of Religion and Human Relations ... It further calls for the retrieval of the said hidden histories of women which would hopefully be a lesson for the contemporary and future women.

45 CFR 2400.63 - Excluded graduate study.

Science.gov (United States)

2010-10-01

... arts in public affairs or public administration. The Foundation may at its discretion, upon request of... 45 Public Welfare 4 2010-10-01 2010-10-01 false Excluded graduate study. 2400.63 Section 2400.63 Public Welfare Regulations Relating to Public Welfare (Continued) JAMES MADISON MEMORIAL FELLOWSHIP...

48 CFR 52.247-7 - Freight Excluded.

Science.gov (United States)

2010-10-01

... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Freight Excluded. 52.247-7... AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of Provisions and Clauses 52.247-7 Freight... contracts for transportation or for transportation-related services when any commodities or types of...

Excluded-volume effects in the diffusion of hard spheres

KAUST Repository

Bruna, Maria

2012-01-03

Excluded-volume effects can play an important role in determining transport properties in diffusion of particles. Here, the diffusion of finite-sized hard-core interacting particles in two or three dimensions is considered systematically using the method of matched asymptotic expansions. The result is a nonlinear diffusion equation for the one-particle distribution function, with excluded-volume effects enhancing the overall collective diffusion rate. An expression for the effective (collective) diffusion coefficient is obtained. Stochastic simulations of the full particle system are shown to compare well with the solution of this equation for two examples. © 2012 American Physical Society.

Analysis of artefacts and detail resolution of lung MRI with breath-hold T1-weighted gradient-echo and T2-weighted fast spin-echo sequences with respiratory triggering

International Nuclear Information System (INIS)

Biederer, J.; Reuter, M.; Both, M.; Grimm, J.; Heller, M.; Muhle, C.; Graessner, J.

2002-01-01

The aim of this study was to evaluate feasibility and limitations of two MR sequences for imaging of the lung using a semi-quantitative rating scale. Ten healthy volunteers were assessed with a breath-hold T1-weighted gradient-recalled-echo (TR/TE=129/2.2 ms, matrix 173 x 256) and a T2-weighted turbo spin-echo (TSE) sequence with respiratory triggering (TR/TE=3000-5000/120 ms, matrix 270 x 512) in axial 6-mm slices. The T1-weighted GRE protocol included a pre-saturation pulse over the mediastinal structures. Artefacts and resolution of vessel/airway structures in each lung segment were evaluated by two observers (10 volunteers, 180 segments). Cardiac and vessel pulsation artefacts predominated on T1-weighted GRE, respiration artefacts on T2-weighted TSE (lingula and middle lobe). Pre-saturation of the mediastinum reduced pulsation artefacts on T1-weighted GRE. T1-weighted GRE images were improved by bright flow signal of vessels, whereas image quality of T2-weighted TSE was reduced by black-blood effects in central parts of the lung. Delineation of lung periphery and the mediastinum was superior with T2-weighted TSE. Segmental/sub-segmental vessels (up to fourth/fifth order) and bronchi (up to third order) were identified. All 180 lung segments were imaged in diagnostic quality with at least one of the two sequences (T1-weighted GRE not diagnostic in 9 of 180, T2-weighted TSE in 4 of 180). Both sequences were found to be complementary: superior identification of gross lung anatomy with T1-weighted GRE and higher detail resolution in the periphery and the mediastinum with T2-weighted TSE. (orig.)

21 CFR 1.362 - What records are excluded from this subpart?

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 1 2010-04-01 2010-04-01 false What records are excluded from this subpart? 1.362 Section 1.362 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL... Requirements § 1.362 What records are excluded from this subpart? The establishment and maintenance of records...

Development of Focused Ion Beam technique for high speed steel 3D-SEM artefact fabrication

DEFF Research Database (Denmark)

Carli, Lorenzo; MacDonald, A. Nicole; De Chiffre, Leonardo

2009-01-01

The work describes preliminary manufacture by grinding, followed by machining on a Focused Ion Beam (FIB), of a high speed steel step artefact for 3D-SEM calibration. The FIB is coupled with a SEM in the so called dual beam instrument. The milling capabilities of FIB were checked from a qualitative...... point of view, using the dual beam SEM imaging, and quantitatively using a reference stylus instrument, to establish traceability. A triangular section having a depth of about 10 μm was machined, where the 50 μm curvature radius due to grinding was reduced to about 2 μm by FIB milling...

The effect of metal artefact reduction on CT-based attenuation correction for PET imaging in the vicinity of metallic hip implants : a phantom study

NARCIS (Netherlands)

Harnish, Roy; Prevrhal, Sven; Alavi, Abass; Zaidi, Habib; Lang, Thomas F.

To determine if metal artefact reduction (MAR) combined with a priori knowledge of prosthesis material composition can be applied to obtain CT-based attenuation maps with sufficient accuracy for quantitative assessment of F-18-fluorodeoxyglucose uptake in lesions near metallic prostheses. A custom

Comparative assessment of knee joint models used in multi-body kinematics optimisation for soft tissue artefact compensation.

Science.gov (United States)

Richard, Vincent; Cappozzo, Aurelio; Dumas, Raphaël

2017-09-06

Estimating joint kinematics from skin-marker trajectories recorded using stereophotogrammetry is complicated by soft tissue artefact (STA), an inexorable source of error. One solution is to use a bone pose estimator based on multi-body kinematics optimisation (MKO) embedding joint constraints to compensate for STA. However, there is some debate over the effectiveness of this method. The present study aimed to quantitatively assess the degree of agreement between reference (i.e., artefact-free) knee joint kinematics and the same kinematics estimated using MKO embedding six different knee joint models. The following motor tasks were assessed: level walking, hopping, cutting, running, sit-to-stand, and step-up. Reference knee kinematics was taken from pin-marker or biplane fluoroscopic data acquired concurrently with skin-marker data, made available by the respective authors. For each motor task, Bland-Altman analysis revealed that the performance of MKO varied according to the joint model used, with a wide discrepancy in results across degrees of freedom (DoFs), models and motor tasks (with a bias between -10.2° and 13.2° and between -10.2mm and 7.2mm, and with a confidence interval up to ±14.8° and ±11.1mm, for rotation and displacement, respectively). It can be concluded that, while MKO might occasionally improve kinematics estimation, as implemented to date it does not represent a reliable solution to the STA issue. Copyright © 2017 Elsevier Ltd. All rights reserved.

20 CFR 404.1013 - Included-excluded rule.

Science.gov (United States)

2010-04-01

... least one-half of your time in the pay period is in covered work. If you spend most of your time in a... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Included-excluded rule. 404.1013 Section 404.1013 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY...

Empowering the digitally excluded: learning initiatives for (invisible groups

Directory of Open Access Journals (Sweden)

Jane Seale

2012-12-01

Full Text Available There is growing evidence that some digitally excluded groups of learners are receiving more attention than others. Discussions regarding why some digitally excluded learners are more visible than others and therefore worthy of more committed digital inclusion interventions raises important questions about how we define and conceptualise digital inclusion and digital inclusion practice; particularly in relation to empowerment. In this article, we draw on a range of research, practice and policy literature to examine two important questions: what is empowerment and in whose hands does empowerment lie? We argue that empowerment involves making informed choices about technology use, but that learners often require support- human intervention- to make these choices. However, current digital inclusion research has failed to produce a detailed critique of what constitutes empowering support from educational institutions and their staff. A lack of open and reflexive accounts of practice means that we are no closer to identifying and understanding the kinds of empowering practices that are required to challenge the kinds of prejudices, stereotypes, risk-aversiveness and low aspirations associated with the most invisible of digitally excluded learners.

Iron corrosion in an anoxic soil: Comparison between thermodynamic modelling and ferrous archaeological artefacts characterised along with the local in situ geochemical conditions

Energy Technology Data Exchange (ETDEWEB)

Saheb, M.; Neff, D.; Michelin, A.; Dillmann, P. [CEA Saclay, CNRS, LAPA SIS2M, UMR3299, 91 - Gif-sur-Yvette (France); Saheb, M. [ANDRA, F-92298 Chatenay Malabry (France); Descostes, M. [CEA Saclay, DEN DANS DPC SECR, Lab Radionuclides Migrat Measurements and Modelling, 91 - Gif-sur-Yvette (France); Descostes, M. [Univ Evry, CEA, CNRS, UMR 8587, Evry (France); Dillmann, P. [CNRS, Inst Rech Archeomat, UMR 5060, F-75700 Paris (France)

2010-07-01

This article is part of an ongoing study on the long-term corrosion behaviour of ferrous archaeological artefacts. The aim of this study is to correlate the corrosion products formed on ancient artefacts in an anoxic medium to the environmental data using thermodynamic modelling. For this purpose, measurement campaigns have been conducted on the archaeological site of Glinet (16. century, High Normandy (Seine-Maritime), France) where the evolution of the pore water chemistry has been recorded for a period of one year. Three evolution steps have been distinguished after the oxidizing perturbation which was induced by the piezometers installation. The first step was related to an oxidizing environment in which pore water was in equilibrium with a Fe(III) precipitated phase: ferri-hydrite (FeOOH center dot 0.4 H{sub 2}O). The second step was considered as an intermediate step and Fe speciation had evolved; equilibrium was achieved between ferri-hydrite and a Fe(II) carbonate phase: siderite (Fe(II)CO{sub 3}). The last step of the evolution was related to a reducing stage where pore water was in equilibrium with magnetite (Fe(II, III){sub 3}O{sub 4}) and with chukanovite (Fe(II){sub 2}(OH){sub 2}CO{sub 3}). As these phases were present in the corrosion layers formed on the archaeological samples, it is possible to conclude that the thermodynamic approach was helpful in developing a better understanding of the effect of geochemical conditions on the composition and mineralogy of the corrosion products formed on archaeological artefacts. This work could be used as a reference for further corrosion studies, especially on long-term corrosion processes applied to nuclear waste disposal. (authors)

The Fundamentals Regarding the Usage of the Concept of Interface for the Modeling of the Software Artefacts

Directory of Open Access Journals (Sweden)

Dorin Bocu

2016-03-01

Full Text Available This paper presents the conceptual foundations of a software system’s solution modelling activity, which is formally based on two essential concepts: the artefact and the interface. This  modelling activity envisions  two  objectives: the  explicit emphasis on the  interfaces’ importance in the software engineering, and the preparation of the  framework inside which  the  loop structure-behaviour can be formalized considering the inherent benefits for the  modelling activity in  general, and  for  the  modelling activity automation in particular.

Metastatic Ewing's sarcoma to the skull: CNS involvement excluded by MRI

International Nuclear Information System (INIS)

Taets ven Amerongen, A.H.M.; Kaiser, M.C.; Waal, F.C. de

1987-01-01

A case of metastatic Ewing's sarcoma to the skull is presented, demonstrating the superiority of magnetic resonance imaging over other imaging modalities to exclude CNS involvement. Precise delineation of different tumor components in extradural location contained in an intact dural rim together with compressed cortex showing no signs of tumorous involvement constituted an MRI appearance allowing us to exclude tumor outgrowth into the brain. (orig.)

Esophageal manometric characteristics and outcomes for laparoscopic esophageal diverticulectomy, myotomy, and partial fundoplication for epiphrenic diverticula.

Science.gov (United States)

Melman, Lora; Quinlan, Jessica; Robertson, Brian; Brunt, L M; Halpin, Valerie J; Eagon, J C; Frisella, Margaret M; Matthews, Brent D

2009-06-01

The purpose of this study is to characterize the esophageal motor and lower esophageal sphincter (LES) abnormalities associated with epiphrenic esophageal diverticula and analyze outcomes for laparoscopic esophageal diverticulectomy, myotomy, and partial fundoplication. The endoscopic, radiographic, manometric, and perioperative records for patients undergoing laparoscopic esophageal diverticulectomy, anterior esophageal myotomy, and partial fundoplication from 8/99 until 9/06 were reviewed from an Institutional Review Board (IRB)-approved outcomes database. Data are given as mean +/- standard deviation (SD). An esophageal body motor disorder and/or LES abnormalities were present in 11 patients with epiphrenic diverticula; three patients were characterized as achalasia, one had vigorous achalasia, two had diffuse esophageal spasm, and five had a nonspecific motor disorder. Presenting symptoms included dysphagia (13/13), regurgitation (7/13), and chest pain (4/13). Three patients had previous Botox injections and three patients had esophageal dilatations. Laparoscopic epiphrenic diverticulectomy with an anterior esophageal myotomy was completed in 13 patients (M:F; 3:10) with a mean age of 67.6 +/- 4.2 years, body mass index (BMI) of 28.1 +/- 1.9 kg/m2 and American Society of Anesthesiologists (ASA) 2.2 +/- 0.1. Partial fundoplication was performed in 12/13 patients (Dor, n = 2; Toupet, n = 10). Four patients had a type I and one patient had a type III hiatal hernia requiring repair. Mean operative time was 210 +/- 15.1 min and mean length of stay (LOS) was 2.8 +/- 0.4 days. Two grade II or higher complications occurred, including one patient who was readmitted on postoperative day 4 with a leak requiring a thoracotomy. After a mean follow-up of 13.6 +/- 3.0 months (range 3-36 months), two patients complained of mild solid food dysphagia and one patient required proton pump inhibitor (PPI) for gastroesophageal reflux disease (GERD) symptoms. The majority of patients

Being Included and Excluded

DEFF Research Database (Denmark)

Korzenevica, Marina

2016-01-01

Following the civil war of 1996–2006, there was a dramatic increase in the labor mobility of young men and the inclusion of young women in formal education, which led to the transformation of the political landscape of rural Nepal. Mobility and schooling represent a level of prestige that rural...... politics. It analyzes how formal education and mobility either challenge or reinforce traditional gendered norms which dictate a lowly position for young married women in the household and their absence from community politics. The article concludes that women are simultaneously excluded and included from...... community politics. On the one hand, their mobility and decision-making powers decrease with the increase in the labor mobility of men and their newly gained education is politically devalued when compared to the informal education that men gain through mobility, but on the other hand, schooling strengthens...

Clean Water Act (excluding Section 404)

Energy Technology Data Exchange (ETDEWEB)

1993-01-15

This Reference Book contains a current copy of the Clean Water Act (excluding Section 404) and those regulations that implement the statutes and appear to be most relevant to US Department of Energy (DOE) activities. The document is provided to DOE and contractor staff for informational purposes only and should not be interpreted as legal guidance. Updates that include important new requirements will be provided periodically. Questions concerning this Reference Book may be directed to Mark Petts, EH-231 (202/586-2609).

Extended Excluded Volume: Its Origin and Consequences

Czech Academy of Sciences Publication Activity Database

Nezbeda, Ivo; Rouha, M.

2013-01-01

Roč. 85, č. 1 (2013), s. 201-210 ISSN 0033-4545. [International Conference on Solution Chemistry (ICSC-32) /32./. La Grande Motte, 28.08.2011-02.09.2011] R&D Projects: GA AV ČR IAA400720802 Institutional support: RVO:67985858 Keywords : excluded volume * partial molar volume * primitive models Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.112, year: 2013

Synchronizing the transcranial magnetic pulse with electroencephalographic recordings effectively reduces inter-trial variability of the pulse artefact

DEFF Research Database (Denmark)

Tomasevic, Leo; Takemi, Mitsuaki; Siebner, Hartwig Roman

2017-01-01

delivered monophasic and biphasic TMS to a melon as head phantom and to four healthy participants and recorded the pulse artefact at 5 kHz with a TMS-compatible EEG system. Pulse delivery was either synchronized or non-synchronized to the clock of the EEG recording system. The effects of synchronization...... were tested at 10 and 20 kHz using the head phantom. We also tested the effect of a soft sheet placed between the stimulation coil and recording electrodes in both human and melon. RESULTS & CONCLUSION: Synchronizing TMS and data acquisition markedly reduced trial-to-trial variability of the pulse...

8 CFR 1240.38 - Fingerprinting of excluded aliens.

Science.gov (United States)

2010-01-01

... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Fingerprinting of excluded aliens. 1240.38 Section 1240.38 Aliens and Nationality EXECUTIVE OFFICE FOR IMMIGRATION REVIEW, DEPARTMENT OF JUSTICE IMMIGRATION REGULATIONS PROCEEDINGS TO DETERMINE REMOVABILITY OF ALIENS IN THE UNITED STATES Exclusion of...

Calibrating the X-ray attenuation of liquid water and correcting sample movement artefacts during in operando synchrotron X-ray radiographic imaging of polymer electrolyte membrane fuel cells.

Science.gov (United States)

Ge, Nan; Chevalier, Stéphane; Hinebaugh, James; Yip, Ronnie; Lee, Jongmin; Antonacci, Patrick; Kotaka, Toshikazu; Tabuchi, Yuichiro; Bazylak, Aimy

2016-03-01

Synchrotron X-ray radiography, due to its high temporal and spatial resolutions, provides a valuable means for understanding the in operando water transport behaviour in polymer electrolyte membrane fuel cells. The purpose of this study is to address the specific artefact of imaging sample movement, which poses a significant challenge to synchrotron-based imaging for fuel cell diagnostics. Specifically, the impact of the micrometer-scale movement of the sample was determined, and a correction methodology was developed. At a photon energy level of 20 keV, a maximum movement of 7.5 µm resulted in a false water thickness of 0.93 cm (9% higher than the maximum amount of water that the experimental apparatus could physically contain). This artefact was corrected by image translations based on the relationship between the false water thickness value and the distance moved by the sample. The implementation of this correction method led to a significant reduction in false water thickness (to ∼0.04 cm). Furthermore, to account for inaccuracies in pixel intensities due to the scattering effect and higher harmonics, a calibration technique was introduced for the liquid water X-ray attenuation coefficient, which was found to be 0.657 ± 0.023 cm(-1) at 20 keV. The work presented in this paper provides valuable tools for artefact compensation and accuracy improvements for dynamic synchrotron X-ray imaging of fuel cells.

21 CFR 1404.950 - Excluded Parties List System

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Excluded Parties List System 1404.950 Section 1404.950 Food and Drugs OFFICE OF NATIONAL DRUG CONTROL POLICY GOVERNMENTWIDE DEBARMENT AND SUSPENSION... other information about persons who are ineligible. The EPLS system includes the printed version...

The Education Act and Excluded Children. Policy Review.

Science.gov (United States)

Hodgkin, Rachel

1997-01-01

Discusses the negative assumptions and outcomes of provisions in Britain's Education Act of 1997 dealing with expulsion of students. Presents some statistics on excluded children; discusses likely outcomes such as increased delinquency, parent-school acrimony, and disparity in schools. Describes the role of teachers' unions in drafting the bill…

Quantitative analysis of orthopedic metal artefact reduction in 64-slice computed tomography scans in large head metal-on-metal total hip replacement, a phantom study

NARCIS (Netherlands)

Boomsma, Martijn F.; Warringa, Niek; Edens, Mireille A.; Mueller, Dirk; Ettema, Harmen B.; Verheyen, Cees C. P. M.; Maas, Mario

2016-01-01

Purpose: Quantification of the effect of O-MAR on decreasing metal artefacts caused by large head metal on metal total hip arthroplasty (MoM THA) in a dedicated phantom setup of the hip. Background: Pathological reactions of the hip capsule on Computed tomography (CT) can be difficult to diagnose

Multi-slice ultrasound image calibration of an intelligent skin-marker for soft tissue artefact compensation.

Science.gov (United States)

Masum, M A; Pickering, M R; Lambert, A J; Scarvell, J M; Smith, P N

2017-09-06

In this paper, a novel multi-slice ultrasound (US) image calibration of an intelligent skin-marker used for soft tissue artefact compensation is proposed to align and orient image slices in an exact H-shaped pattern. Multi-slice calibration is complex, however, in the proposed method, a phantom based visual alignment followed by transform parameters estimation greatly reduces the complexity and provides sufficient accuracy. In this approach, the Hough Transform (HT) is used to further enhance the image features which originate from the image feature enhancing elements integrated into the physical phantom model, thus reducing feature detection uncertainty. In this framework, slice by slice image alignment and calibration are carried out and this provides manual ease and convenience. Copyright © 2016 Elsevier Ltd. All rights reserved.

Goldtraces on wedge-shaped artefacts from late neolithic of south Scandinavia analysed by proton induced x-ray emission spectroscopy

International Nuclear Information System (INIS)

Ahlberg, M.; Akselsson, R.; Forkman, B.; Rausing, G.

1975-01-01

Visible coloured traces on the surface of two selected wedge-shaped artefacts (pendants) of slate from the late Neolithic of South Scandinavia was analysed by means of proton-induced x-ray emission spectroscopy (PIXE). PIXE is shown to be a feasible tool in investigating surface layers of archeological significance. Three different gold-silver alloys was found on the two pendants. The results indicate that we shall have to reconsider the general accepted theories on the economic basis of the early Bronze Age in the area. (author)

Excluded-volume effects in the diffusion of hard spheres

KAUST Repository

Bruna, Maria; Chapman, S. Jonathan

2012-01-01

Excluded-volume effects can play an important role in determining transport properties in diffusion of particles. Here, the diffusion of finite-sized hard-core interacting particles in two or three dimensions is considered systematically using

Excluded-Mean-Variance Neural Decision Analyzer for Qualitative Group Decision Making

Directory of Open Access Journals (Sweden)

Ki-Young Song

2012-01-01

Full Text Available Many qualitative group decisions in professional fields such as law, engineering, economics, psychology, and medicine that appear to be crisp and certain are in reality shrouded in fuzziness as a result of uncertain environments and the nature of human cognition within which the group decisions are made. In this paper we introduce an innovative approach to group decision making in uncertain situations by using a mean-variance neural approach. The key idea of this proposed approach is to compute the excluded mean of individual evaluations and weight it by applying a variance influence function (VIF; this process of weighting the excluded mean by VIF provides an improved result in the group decision making. In this paper, a case study with the proposed excluded-mean-variance approach is also presented. The results of this case study indicate that this proposed approach can improve the effectiveness of qualitative decision making by providing the decision maker with a new cognitive tool to assist in the reasoning process.

Metal artefacts severely hamper magnetic resonance imaging of the rotator cuff tendons after rotator cuff repair with titanium suture anchors.

Science.gov (United States)

Schröder, Femke F; Huis In't Veld, Rianne; den Otter, Lydia A; van Raak, Sjoerd M; Ten Haken, Bennie; Vochteloo, Anne J H

2018-04-01

The rate of retear after rotator cuff surgery is 17%. Magnetic resonance imaging (MRI) scans are used for confirmative diagnosis of retear. However, because of the presence of titanium suture anchors, metal artefacts on the MRI are common. The present study evaluated the diagnostic value of MRI after rotator cuff tendon surgery with respect to assessing the integrity as well as the degeneration and atrophy of the rotator cuff tendons when titanium anchors are in place. Twenty patients who underwent revision surgery of the rotator cuff as a result of a clinically suspected retear between 2013 and 2015 were included. The MRI scans of these patients were retrospectively analyzed by four specialized shoulder surgeons and compared with intra-operative findings (gold standard). Sensitivity and interobserver agreement among the surgeons in assessing retears as well as the Goutallier and Warner classification were examined. In 36% (range 15% to 50%) of the pre-operative MRI scans, the observers could not review the rotator cuff tendons. When the rotator cuff tendons were assessable, a diagnostic accuracy with a mean sensitivity of 0.84 (0.70 to 1.0) across the surgeons was found, with poor interobserver agreement (kappa = 0.12). Metal artefacts prevented accurate diagnosis from MRI scans of rotator cuff retear in 36% of the patients studied.

Cell respiration under hypoxia: facts and artefacts in mitochondrial oxygen kinetics.

Science.gov (United States)

Scandurra, Francesca M; Gnaiger, Erich

2010-01-01

When oxygen supply to tissues is limiting, mitochondrial respiration and ATP production are compromised. To assess the bioenergetic consequences under normoxia and hypoxia, quantitative evaluation of mitochondrial oxygen kinetics is required. Using high-resolution respirometry, the "apparent K (m)" for oxygen or p (50) of respiration in 32D cells was determined at 0.05 +/- 0.01 kPa (0.4 mmHg, 0.5 microM, 0.25% air saturation). Close agreement with p (50) of isolated mitochondria indicates that intracellular gradients are small in small cells at routine activity. At intracellular p (O2) respiration is limited by >2% with a p (50) of 0.05 kPa. Over-estimation of p (50) at 0.4 kPa (3 mmHg) would imply significant (>17%) oxygen limitation of respiration under intracellular normoxia. Based on a critical review, we conclude that p (50) ranges from 0.01 to 0.10 kPa in mitochondria and small cells in the absence of inhibitors of cytochrome c oxidase, whereas experimental artefacts explain the controversial >200-fold range of p (50) in the literature on mitochondrial oxygen kinetics.

Supporting BPMN choreography with system integration artefacts for enterprise process collaboration

Science.gov (United States)

Nie, Hongchao; Lu, Xudong; Duan, Huilong

2014-07-01

Business Process Model and Notation (BPMN) choreography modelling depicts externally visible message exchanges between collaborating processes of enterprise information systems. Implementation of choreography relies on designing system integration solutions to realise message exchanges between independently developed systems. Enterprise integration patterns (EIPs) are widely accepted artefacts to design integration solutions. If the choreography model represents coordination requirements between processes with behaviour mismatches, the integration designer needs to analyse the routing requirements and address these requirements by manually designing EIP message routers. As collaboration scales and complexity increases, manual design becomes inefficient. Thus, the research problem of this paper is to explore a method to automatically identify routing requirements from BPMN choreography model and to accordingly design routing in the integration solution. To achieve this goal, recurring behaviour mismatch scenarios are analysed as patterns, and corresponding solutions are proposed as EIP routers. Using this method, a choreography model can be analysed by computer to identify occurrences of mismatch patterns, leading to corresponding router selection. A case study demonstrates that the proposed method enables computer-assisted integration design to implement choreography. A further experiment reveals that the method is effective to improve the design quality and reduce time cost.

Diffusion of multiple species with excluded-volume effects

KAUST Repository

Bruna, Maria; Chapman, S. Jonathan

2012-01-01

Stochastic models of diffusion with excluded-volume effects are used to model many biological and physical systems at a discrete level. The average properties of the population may be described by a continuum model based on partial differential equations. In this paper we consider multiple interacting subpopulations/species and study how the inter-species competition emerges at the population level. Each individual is described as a finite-size hard core interacting particle undergoing Brownian motion. The link between the discrete stochastic equations of motion and the continuum model is considered systematically using the method of matched asymptotic expansions. The system for two species leads to a nonlinear cross-diffusion system for each subpopulation, which captures the enhancement of the effective diffusion rate due to excluded-volume interactions between particles of the same species, and the diminishment due to particles of the other species. This model can explain two alternative notions of the diffusion coefficient that are often confounded, namely collective diffusion and self-diffusion. Simulations of the discrete system show good agreement with the analytic results. © 2012 American Institute of Physics.

Spectral artefacts post sputter-etching and how to cope with them - A case study of XPS on nitride-based coatings using monoatomic and cluster ion beams

Science.gov (United States)

Lewin, Erik; Counsell, Jonathan; Patscheider, Jörg

2018-06-01

The issue of artefacts due to sputter-etching has been investigated for a group of AlN-based thin film materials with varying thermodynamical stability. Stability of the materials was controlled by alloying AlN with the group 14 elements Si, Ge or Sn in two different concentrations. The coatings were sputter-etched with monoatomic Ar+ with energies between 0.2 and 4.0 keV to study the sensitivity of the materials for sputter damage. The use of Arn+ clusters to remove an oxidised surface layer was also evaluated for a selected sample. The spectra were compared to pristine spectra obtained after in-vacuo sample transfer from the synthesis chamber to the analysis instrument. It was found that the all samples were affected by high energy (4 keV) Ar+ ions to varying degrees. The determining factors for the amount of observed damage were found to be the materials' enthalpy of formation, where a threshold value seems to exist at approximately -1.25 eV/atom (∼-120 kJ/mol atoms). For each sample, the observed amount of damage was found to have a linear dependence to the energy deposited by the ion beam per volume removed material. Despite the occurrence of sputter-damage in all samples, etching settings that result in almost artefact-free spectral data were found; using either very low energy (i.e. 200 eV) monoatomic ions, or an appropriate combination of ion cluster size and energy. The present study underlines that analysis post sputter-etching must be carried out with an awareness of possible sputter-induced artefacts.

The impact of Digitalization on Business Models: How IT Artefacts, Social Media, and Big Data Force Firms to Innovate Their Business Model

OpenAIRE

Bouwman, Harry; de Reuver, Mark; Nikou, Shahrokh

2017-01-01

Digital technology has forced entrepreneurs to reconsider their business models (BMs). Although research on entrepreneurial intention and business models is gaining attention, there is still a large knowledge gap on both fields. In this paper, we specifically address the impact of digitalization on business model innovation (BMI). Based on data collected from 338 European small- to medium-sized enterprises (SMEs) actively using IT artefacts, social media, or big data to innovate their busines...

University Benefits Survey. Part 1 (All Benefits Excluding Pensions).

Science.gov (United States)

University of Western Ontario, London.

Results of a 1983 survey of benefits, excluding pensions, for 17 Ontario, Canada, universities are presented. Information is provided on the following areas: whether the university self-administers insurance plans, communication of benefits, proposed changes in benefits, provision of life and dismemberment insurance, maternity leave policy,…

Use of neutron diffraction and laser-induced plasma spectroscopy in integrated authentication methodologies of copper alloy artefacts

International Nuclear Information System (INIS)

Siano, S.; Bartol, L.; Mencaglia, A.A.; Agresti, J.; Miccio, M.

2009-01-01

The present study approaches the general problem of the authentication of copper alloy artefacts of art and historical interest using non-invasive analytical techniques. It aims to demonstrate that a suitable combination of time-of-flight neutron diffraction and laser-induced plasma spectroscopy in integrated multidisciplinary authentication methodologies can provide crucial data for discriminating between genuine archaeological objects and modern counterfeits. After introducing the methodology, which is dedicated in particular to copper alloy figurines of ancient style, two representative authentication case studies are discussed. The results of the work provide evidence that the combination of multiphase analysis using TOF-N D and elemental depth profiles provided by Lips makes it possible to solve most of the present authentication problems.

A cell shrinkage artefact in growth plate chondrocytes with common fixative solutions: importance of fixative osmolarity for maintaining morphology

Directory of Open Access Journals (Sweden)

MY Loqman

2010-05-01

Full Text Available The remarkable increase in chondrocyte volume is a major determinant in the longitudinal growth of mammalian bones. To permit a detailed morphological study of hypertrophic chondrocytes using standard histological techniques, the preservation of normal chondrocyte morphology is essential. We noticed that during fixation of growth plates with conventional fixative solutions, there was a marked morphological (shrinkage artifact, and we postulated that this arose from the hyper-osmotic nature of these solutions. To test this, we fixed proximal tibia growth plates of 7-day-old rat bones in either (a paraformaldehyde (PFA; 4%, (b glutaraldehyde (GA; 2% with PFA (2% with ruthenium hexamine trichloride (RHT; 0.7%, (c GA (2% with RHT (0.7%, or (d GA (1.3% with RHT (0.5% and osmolarity adjusted to a ‘physiological’ level of ~280mOsm. Using conventional histological methods, confocal microscopy, and image analysis on fluorescently-labelled fixed and living chondrocytes, we then quantified the extent of cell shrinkage and volume change. Our data showed that the high osmolarity of conventional fixatives caused a shrinkage artefact to chondrocytes. This was particularly evident when whole bones were fixed, but could be markedly reduced if bones were sagittally bisected prior to fixation. The shrinkage artefact could be avoided by adjusting the osmolarity of the fixatives to the osmotic pressure of normal extracellular fluids (~280mOsm. These results emphasize the importance of fixative osmolarity, in order to accurately preserve the normal volume/morphology of cells within tissues.

Not all that glitters is gold - Electron microscopy study on uptake of gold nanoparticles in Daphnia magna and related artefacts

DEFF Research Database (Denmark)

Jensen, Louise Helene Søgaard; Skjolding, Lars Michael; Thit, Amalie

2017-01-01

techniques are used to investigate internalization of 10 nm gold nanoparticles in Daphnia magna gut lumen and gut epithelial cells upon 24h exposure and outline potential artefacts, i.e. high contract precipitates from sample preparation related to these techniques. Light sheet microscopy confirmed...... accumulation of gold nanoparticles in the gut lumen. Scanning transmission electron microscopy and elemental analysis revealed gold nanoparticles attached to the microvilli of gut cells. Interestingly, the peritrophic membrane appeared to act as a semipermeable barrier between the lumen and the gut epithelium...

Office of Inspector General List of Excluded Individuals and Entities

Data.gov (United States)

U.S. Department of Health & Human Services — The objective is to ensure that providers who bill Federal health care programs do not submit claims for services furnished, ordered or prescribed by an excluded...

Metastatic Ewing's sarcoma to the skull: CNS involvement excluded by MRI

Energy Technology Data Exchange (ETDEWEB)

Taets ven Amerongen, A.H.M.; Kaiser, M.C.; Waal, F.C. de

1987-03-01

A case of metastatic Ewing's sarcoma to the skull is presented, demonstrating the superiority of magnetic resonance imaging over other imaging modalities to exclude CNS involvement. Precise delineation of different tumor components in extradural location contained in an intact dural rim together with compressed cortex showing no signs of tumorous involvement constituted an MRI appearance allowing us to exclude tumor outgrowth into the brain.

On artefact-free reconstruction of low-energy (30–250 eV) electron holograms

Energy Technology Data Exchange (ETDEWEB)

Latychevskaia, Tatiana, E-mail: tatiana@physik.uzh.ch; Longchamp, Jean-Nicolas; Escher, Conrad; Fink, Hans-Werner

2014-10-15

Low-energy electrons (30–250 eV) have been successfully employed for imaging individual biomolecules. The most simple and elegant design of a low-energy electron microscope for imaging biomolecules is a lensless setup that operates in the holographic mode. In this work we address the problem associated with the reconstruction from the recorded holograms. We discuss the twin image problem intrinsic to inline holography and the problem of the so-called biprism-like effect specific to low-energy electrons. We demonstrate how the presence of the biprism-like effect can be efficiently identified and circumvented. The presented sideband filtering reconstruction method eliminates the twin image and allows for reconstruction despite the biprism-like effect, which we demonstrate on both, simulated and experimental examples. - Highlights: • Radiation damage-free imaging of individual biomolecules. • Elimination of the twin image in inline holograms. • Circumventing biprism-like effect in low-energy electron holograms. • Artefact-free reconstructions of low-energy electron holograms.

On artefact-free reconstruction of low-energy (30–250 eV) electron holograms

International Nuclear Information System (INIS)

Latychevskaia, Tatiana; Longchamp, Jean-Nicolas; Escher, Conrad; Fink, Hans-Werner

2014-01-01

Low-energy electrons (30–250 eV) have been successfully employed for imaging individual biomolecules. The most simple and elegant design of a low-energy electron microscope for imaging biomolecules is a lensless setup that operates in the holographic mode. In this work we address the problem associated with the reconstruction from the recorded holograms. We discuss the twin image problem intrinsic to inline holography and the problem of the so-called biprism-like effect specific to low-energy electrons. We demonstrate how the presence of the biprism-like effect can be efficiently identified and circumvented. The presented sideband filtering reconstruction method eliminates the twin image and allows for reconstruction despite the biprism-like effect, which we demonstrate on both, simulated and experimental examples. - Highlights: • Radiation damage-free imaging of individual biomolecules. • Elimination of the twin image in inline holograms. • Circumventing biprism-like effect in low-energy electron holograms. • Artefact-free reconstructions of low-energy electron holograms

The characterisation of non-evaporable getters by Auger electron spectroscopy Analytical potential and artefacts

CERN Document Server

Scheuerlein, C; Taborelli, M

2002-01-01

The surfaces of getter materials are particularly difficult to analyse because of their high chemical reactivity. The results obtained can be strongly influenced by the experimental set-up and procedures. In this paper the experimental influence on the Auger electron spectroscopy results is discussed, based on the measurements of more than 100 different non-evaporable getter (NEG) materials. There are four typical changes in the Auger electron spectra when a NEG becomes activated. The oxygen peak intensity decreases, the shape of the metal peaks changes, the carbon peak shape changes shape and intensity and a chlorine peak occurs. All these changes are affected by instrumental artefacts. The Zr-MNV peak shape changes occurring during the reduction of ZrO2 are well suited to determine the onset of NEG activation, while the slope with which the O-KLL peak intensity decreases in a certain temperature range is a better criterion for the determination of the temperature at which activation is complete. The O-KLL i...

Diffuse esophageal spasm

International Nuclear Information System (INIS)

Ott, D.J.; Chen, Y.M.; Hewson, E.G.; Richter, J.E.; Wu, W.C.; Gelfand, D.W.; Castell, D.O.

1988-01-01

Radiologic and manometric findings were correlated in 17 patients with diffuse esophageal spasm (DES). All patients initially had chest pain and/or dysphagia and had a manometric diagnosis of DES. Mean percentage of normal peristalsis manometrically was 46% (range, 20%-80%). Based on radiologic examination, an esophageal motor disorder consistent with DES was diagnosed in 12 of 17 patients, and there was one misinterpretation of achalasia. Radiologic detection was not related significantly to the percentage of peristalsis seen on manometric examination. Mean esophageal wall thickness as measured radiographically in patients with DES was 2.6 mm, compared with 2.5 mm in 17 individuals with normal results of manometry

How robots challenge institutional practices

DEFF Research Database (Denmark)

Hasse, Cathrine

2018-01-01

In a globalized world, tools are not what they used to be. Artefacts are material and ideal, but they are often used by people other than those who made them, creating a culture-culture split. The person who creates an artefact perceives it in one way; whereas the people who use it learn how to p...... ultimately concluded that overarching motives of the everyday work of the staff determined whether they included the material artefact, the robot, in their activities as meaningful, or excluded it as meaningless....... to perceive it in relation their own activity settings and local institutional practices. In this article, I draw on a recent study of the introduction of a robot helper into the activity setting of a Danish rehabilitation centre to examine this split and to identify the processes by which material artefacts...... may or may not become embedded within cultures. The study traced how the staff at the centre made efforts to find uses for the robot, but ultimately recognised that they needed to reject it, as the demands made by the technology prevented their pursuing what they saw as the primary purposes...

7 CFR 1794.21 - Categorically excluded proposals without an ER.

Science.gov (United States)

2010-01-01

... UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE (CONTINUED) ENVIRONMENTAL POLICIES AND PROCEDURES... or the substitution of one fuel combustion technology with another is excluded from this... providing service to customers or facilities such as stock tanks and irrigation pumps. (26) New bulk...

40 CFR 761.187 - Reporting importers and by persons generating PCBs in excluded manufacturing processes.

Science.gov (United States)

2010-07-01

...) MANUFACTURING, PROCESSING, DISTRIBUTION IN COMMERCE, AND USE PROHIBITIONS General Records and Reports § 761.187 Reporting importers and by persons generating PCBs in excluded manufacturing processes. In addition to... generating PCBs in excluded manufacturing processes. 761.187 Section 761.187 Protection of Environment...

Provenance analysis of Roman stone artefacts from sedimentary rocks from the archaeological site near Mošnje, NW Slovenia

Directory of Open Access Journals (Sweden)

Snježana Miletić

2016-08-01

Full Text Available This study deals with the macroscopic and microfacies characterisation of Roman stone artefacts excavated in 2006 from a Roman villa rustica near Mošnje (NW Slovenia with the aim of defiing their provenance. A total of 28 representative fids (querns, mortars, whetstones, tooled and rounded stones, a fragment of stone slab, mosaic tesserae and two architectural elements - one with a relief made of clastic and carbonate sedimentary rocks were examined. Comparison was made with rock samples taken from quarries and gravel bars close to the archaeological site, as well as from larger distance to the site. The majority of artefact sampled is composed of Upper Palaeozoic quartz sandstones, which are found as pebbles in gravel bars close to the archaeological site; while 2 samples were from Quaternary coarse grained clastic rocks which can be found in local glacio-flvial sediments. Other fids were made of four different Mesozoic shallow-water limestones which outcrop in different areas of Central and SW Slovenia. The nearest Lower Jurassic biopelmicritic limestones are found at the western periphery of Ljubljana in Podutik. Cretaceous miliolid limestones and biocalcarenitic limestones with rudists are common in the successions of the Dinaric Carbonate Platform in SW Slovenia (for example, on the Trieste-Komen Plateau, NE Italy and SW Croatia. This indicates that the limestones for architectural elements, stone mortars and tesserae were brought to Mošnje from distant locations. Smaller stone tools are likely to have been made at the location of the archaeological site from material gathered locally, mostly pebbles from clastic rocks, which were accessible and suitable for tooling.

Re-Appraisal of Estrogen Receptor Negative/Progesterone Receptor Positive (ER-/PR+) Breast Cancer Phenotype: True Subtype or Technical Artefact?

Science.gov (United States)

Foley, Niamh M; Coll, J M; Lowery, A J; Hynes, S O; Kerin, M J; Sheehan, M; Brodie, C; Sweeney, K J

2017-09-11

Expression of the ER and PR receptors is routinely quantified in breast cancer as a predictive marker of response to hormonal therapy. Accurate determination of ER and PR status is critical to the optimal selection of patients for targeted therapy. The existence of an ER-/PR+ subtype is controversial, with debate centred on whether this represents a true phenotype or a technical artefact on immunohistochemistry (IHC). The aim of this study was to investigate the true incidence and clinico-pathological features of ER-/PR+ breast cancers in a tertiary referral symptomatic breast unit. Clinico-pathological data were collected on invasive breast cancers diagnosed between 1995 and 2005. IHC for ER and PR receptors was repeated on all cases which were ER-/PR+, with the same paraffin block used for the initial diagnostic testing. Concordance between the diagnostic and repeat IHC was determined using validated testing. Complete data, including ER and PR status were available for 697 patients diagnosed during the study period. On diagnostic IHC, the immunophenotype of the breast tumours was: ER+/PR+ in 396 (57%), ER-/PR- in 157 (23%), ER+/PR- in 88 (12%) and ER-/PR+ in 56 (8.6%) patients. On repeat IHC of 48/56 ER-/PR+ tumours 45.8% were ER+/PR+, 6% were ER+/PR- and 43.7% were ER-/PR- None of the cases were confirmed to be ER-/PR+. The ER-/PR+ phenotypic breast cancer is likely to be the result of technical artefact. Prompt reassessment of patients originally assigned to this subtype who re-present with symptoms should be considered to ensure appropriate clinical management.

Influences of excluded volume of molecules on signaling processes on the biomembrane.

Directory of Open Access Journals (Sweden)

Masashi Fujii

Full Text Available We investigate the influences of the excluded volume of molecules on biochemical reaction processes on 2-dimensional surfaces using a model of signal transduction processes on biomembranes. We perform simulations of the 2-dimensional cell-based model, which describes the reactions and diffusion of the receptors, signaling proteins, target proteins, and crowders on the cell membrane. The signaling proteins are activated by receptors, and these activated signaling proteins activate target proteins that bind autonomously from the cytoplasm to the membrane, and unbind from the membrane if activated. If the target proteins bind frequently, the volume fraction of molecules on the membrane becomes so large that the excluded volume of the molecules for the reaction and diffusion dynamics cannot be negligible. We find that such excluded volume effects of the molecules induce non-trivial variations of the signal flow, defined as the activation frequency of target proteins, as follows. With an increase in the binding rate of target proteins, the signal flow varies by i monotonically increasing; ii increasing then decreasing in a bell-shaped curve; or iii increasing, decreasing, then increasing in an S-shaped curve. We further demonstrate that the excluded volume of molecules influences the hierarchical molecular distributions throughout the reaction processes. In particular, when the system exhibits a large signal flow, the signaling proteins tend to surround the receptors to form receptor-signaling protein clusters, and the target proteins tend to become distributed around such clusters. To explain these phenomena, we analyze the stochastic model of the local motions of molecules around the receptor.

How excluding some benefits from value assessment of new drugs impacts innovation.

Science.gov (United States)

Cook, Joseph P; Golec, Joseph

2017-12-01

Payers often assess the benefits of new drugs relative to costs for reimbursement purposes, but they frequently exclude some drugs' option-related benefits, reducing their reimbursement chances, and making them less attractive R&D investments. We develop and test a real options model of R&D investment that shows that excluding option-related benefits heightens drug developers' incentives to avoid high-risk (volatile) R&D investments and instead encourages them to focus on "safer" (positively skewed) investments. Our model and empirical results could partly explain the decline in the number of risky new molecular entities. Copyright © 2017 John Wiley & Sons, Ltd.

Interaction of pulse laser radiation of 532 nm with model coloration layers for medieval stone artefacts

Energy Technology Data Exchange (ETDEWEB)

Colson, J. [University of Vienna, Department of Physical Chemistry, A-1090 Vienna (Austria); Nimmrichter, J. [Austrian Federal Office for the Care of Monuments, Department for Conservation and Restoration, Arsenal, Objekt 15, Tor 4, A-1030 Vienna (Austria); Kautek, W., E-mail: wolfgang.kautek@univie.ac.at [University of Vienna, Department of Physical Chemistry, A-1090 Vienna (Austria)

2014-05-01

Multilayer polychrome coatings on medieval and Renaissance stone artefacts represent substantial challenges in laser cleaning. Therefore, polychromic models with classical pigments, minium (Pb{sub 2}{sup 2+}Pb{sup 4+}O{sub 4}), zinc white (ZnO), and lead white ((PbCO{sub 3}){sub 2}·Pb(OH){sub 2}) in an acrylic binder, were irradiated with a Q-switched Nd:YAG laser emitting at 532 nm. The studied medieval pigments exhibit strongly varying incubation behaviours directly correlated to their band gap energies. Higher band gaps beyond the laser photon energy of 2.3 eV require more incubative generation of defects for resonant transitions. A matching of the modification thresholds after more than four laser pulses was observed. Laser cleaning with multiple pulsing should not exceed ca. 0.05 J/cm{sup 2} when these pigments coexist in close spatial proximity.

31 CFR 19.500 - What is the purpose of the Excluded Parties List System (EPLS)?

Science.gov (United States)

2010-07-01

... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false What is the purpose of the Excluded Parties List System (EPLS)? 19.500 Section 19.500 Money and Finance: Treasury Office of the Secretary of the Treasury GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) Excluded Parties List System...

Social Analysis in Development Interventions: Policy Artefact or Constructive Transformation?

Directory of Open Access Journals (Sweden)

SUSANNA PRICE

2012-02-01

Full Text Available Recently attention has focused on the role of social researchers in the processes of construction and transmission of knowledge about global poverty and its reduction. This paper examines some of the formative efforts by pioneering social researchers in development institutions to step into the realm of policy making to construct processes for project preparation and management through social analysis. Before 1970 development planners invoked ‘social' or ‘human' factors only as an excuse to explain away project failures - they designed and implemented development projects in the absence of any strategies or regulatory frameworks for managing their social impacts. Recognizing that project investments represent induced change and constitute a social process in themselves, pioneering social researchers constructed policies and procedures to introduce sociological content and method into the project cycle and so re-order social outcomes. Were such constructs merely policy artefacts? Even as the constructs helped to shift the statements of the development discourse towards ‘people oriented' poverty reduction, new modalities appeared which tested the limits of the agreed methods. Institutions may forget, neglect, contest or re-write the documents if in perceived conflict with the institutional ‘core business'. Yet those pioneering efforts created institutional space for, and understanding of, social analysis, with a measure of flow-on international recognition. Tracking social analysis in several international institutions and in a significant emerging economy, China, this paper highlights not only a history full of lessons to be learned where social analysis is not practiced systematically but also outlines some future challenges.

Exploring young children’s artefact engagements as premises for creating purposeful intergenerational knowledge of digitalized everyday life

DEFF Research Database (Denmark)

Chimirri, Niklas Alexander

The presentation takes its point of departure in a major current expression of the top-down steering rationale in Danish Early Childhood Education and Care, namely the process of digitalization of childcare institutions. While the promotion of using digital artefacts in childcare can be seen...... as reflecting actual and seemingly unavoidable current transformations of the everyday life of adults and children across all societal practices, rendering the political wish to strengthening the digital media literacy of its ‘future citizens’ comprehensible, the ways in which digitalization is promoted...... by state policies accounts little for the ambivalences of digitalized everyday life at home and other relevant contexts. Instead of taking adults’ and children’s digital being seriously and granting opportunities to jointly explore digital artefacts’ possibilities and limitations, hence, childcare...

From artefacts to atoms - A new SI for 2018 to be based on fundamental constants.

Science.gov (United States)

Quinn, Terry

At the 26th General Conference on Weights and Measures (CGPM) in November 2018, it is planned to adopt a new definition of the International System of Units, SI, based on the fixed numerical values of seven defining constants, broadly the fundamental constants of physics. This will be the culmination of more than two hundred years of metrology, instantiating for the first time the original ideas of the creators of the metric system. The key is the replacement of the present definition of the unit of mass, the kilogram artefact of platinum-iridium, by one based on a fixed numerical value of the Planck constant. This article outlines how this has come about, how it will work, why we need a system of measurement that is uniform, accessible world-wide and stable in the long term, and the international structures that now exist to achieve it. Copyright © 2017 Elsevier Ltd. All rights reserved.

Clinical Diagnosis of Achalasia: How Reliable is the Barium X-Ray?

Directory of Open Access Journals (Sweden)

I El-Takli

2006-01-01

Full Text Available Manometry is considered to be the gold standard for the diagnosis of achalasia. However, many physicians believe that contrast radiography, classically showing esophageal dilation with bird-beak narrowing of the gastroesophageal junction, is also accurate in either diagnosing or excluding the disorder. The aim of the current study was to determine the accuracy of barium x-ray in the diagnosis of achalasia. The radiological diagnosis of all patients manometrically diagnosed with achalasia (using conventional criteria between January 1994 and June 1998 were reviewed. A total of 51 cases of achalasia were identified. Thirteen patients were excluded because they either did not have contrast radiography before a manometric diagnosis or had their x-rays performed more than six months previously. Of the remaining 38 patients, achalasia was stated as a diagnostic possibility in the radiologists report in only 22 (58% of those patients. Achalasia was not considered in the remaining 16 patients: two were reported as normal, four as having stenosis/narrowing in distal esophagus, two as having presbyesophagus, one as having mild gastroesophageal reflux and seven as having nonspecific dysmotility. To determine the reason for the diagnostic failure of the barium x-ray, an expert gastrointestinal radiologist reviewed 12 of the nondiagnostic x-rays in a blinded fashion, interspersed with 10 randomly selected esophageal-contrast radiographs from control subjects to avoid bias. Of these initially nondiagnostic x-rays in achalasia patients, typical radiological features of achalasia were deemed to be present in 50%. The present study indicates that contrast radiography lacks sensitivity in the diagnosis of achalasia. This is not only due to radiologist oversight but also because of the absence of the characteristic radiological features in many cases. This reinforces the important role of esophageal manometry in patients with persistent nonstructural dysphagia.

The artefacts of radiochromic film dosimetry with flatbed scanners and their causation by light scattering from radiation-induced polymers.

Science.gov (United States)

Schoenfeld, Andreas A; Poppinga, Daniela; Harder, Dietrich; Doerner, Karl-Joachim; Poppe, Bjoern

2014-07-07

Optical experiments and theoretical considerations have been undertaken in order to understand the causes of the 'orientation effect' and the 'parabola effect', the artefacts impairing the desired light absorption measurement on radiochromic EBT3 films with flatbed scanners. EBT3 films exposed to doses up to 20.9 Gy were scanned with an Epson Expression 10000XL flatbed scanner in landscape and portrait orientation. The horizontally and vertically polarized light components of the scanner were determined, and another Epson Expression 10000XL flatbed scanner was disassembled to examine its optical components. The optical properties of exposed and unexposed EBT3 films were studied with incident polarized and unpolarized white light, and the transmitted red light was investigated for its polarization and scattering properties including the distribution of the scattering angles. Neutral density filters were studied for comparison. Guidance was sought from the theory of light scattering from rod-like macromolecular structures. The drastic dose-dependent variation of the transmitted total light current as function of the orientation of front and rear polarizers, interpreted by light scattering theory, shows that the radiation-induced polymerization of the monomers of EBT3 films produces light scattering oscillators preferably polarized at right angles with the coating direction of the film. The directional distribution of the scattered light is partly anisotropic, with a preferred scattering plane at right angles with the coating direction, indicating light scattering from stacks of coherently vibrating oscillators piled up along the monomer crystals. The polyester carrier film also participates in these effects. The 'orientation' and 'parabola' artefacts due to flatbed scanning of radiochromic films can be explained by the interaction of the polarization-dependent and anisotropic light scattering from exposed and unexposed EBT3 films with the quantitative difference

Addressing dichotomous data for participants excluded from trial analysis: a guide for systematic reviewers.

Directory of Open Access Journals (Sweden)

Elie A Akl

Full Text Available Systematic reviewer authors intending to include all randomized participants in their meta-analyses need to make assumptions about the outcomes of participants with missing data.The objective of this paper is to provide systematic reviewer authors with a relatively simple guidance for addressing dichotomous data for participants excluded from analyses of randomized trials.This guide is based on a review of the Cochrane handbook and published methodological research. The guide deals with participants excluded from the analysis who were considered 'non-adherent to the protocol' but for whom data are available, and participants with missing data.Systematic reviewer authors should include data from 'non-adherent' participants excluded from the primary study authors' analysis but for whom data are available. For missing, unavailable participant data, authors may conduct a complete case analysis (excluding those with missing data as the primary analysis. Alternatively, they may conduct a primary analysis that makes plausible assumptions about the outcomes of participants with missing data. When the primary analysis suggests important benefit, sensitivity meta-analyses using relatively extreme assumptions that may vary in plausibility can inform the extent to which risk of bias impacts the confidence in the results of the primary analysis. The more plausible assumptions draw on the outcome event rates within the trial or in all trials included in the meta-analysis. The proposed guide does not take into account the uncertainty associated with assumed events.This guide proposes methods for handling participants excluded from analyses of randomized trials. These methods can help in establishing the extent to which risk of bias impacts meta-analysis results.

Identification of cadmium-excluding Welsh onion (Allium fistulosum L.) cultivars and their mechanisms of low cadmium accumulation.

Science.gov (United States)

Li, Xuhui; Zhou, Qixing; Wei, Shuhe; Ren, Wenjie

2012-06-01

Screening out cadmium (Cd) excluding cultivars of a crop in agricultural production is an effective way to prohibit Cd entering into food chain. A judging criterion for Cd-excluding cultivars based on food safety was suggested and used in the identification of Cd-excluding welsh onion (Allium fistulosum L.) cultivars. A pot culture experiment was carried out to screen out Cd-excluding cultivars, of which the results were confirmed by plot experiments. The relevant factors of Cd accumulation in the pseudostem were analyzed and used in the correlation analysis aiming to study the low Cd accumulation mechanisms. The concentration of Cd in the pseudostem of welsh onions was 0.08-0.20, 0.18-0.41, and 0.26-0.61 mg/kg fresh weight (FW) under three treatments (1.0, 2.5, and 5.0 mg/kg), respectively. The significant (p onion cultivars, but Cd contamination in soil had little influence on biomass and the contents of soluble sugar, NO(3)(-)-N, and eight other elements in the tested welsh onion cultivars. Two cultivars were identified as Cd-excluding cultivars, mainly because the accumulation of Cd in their pseudostem was only 0.041 ± 0.003 and 0.046 ± 0.002 mg/kg FW, and 0.054 ± 0.001 and 0.066 ± 0.011 mg/kg FW, when growing in plots with Cd concentration of 0.49 and 0.99 mg/kg, respectively. Ribentiegancongwang and Wuyeqi could be identified as Cd-excluding cultivars. Low bioaccumulation factor of the roots was the main mechanism of Cd-excluding welsh onion cultivars.

Oxytocin biases men but not women to restore social connections with individuals who socially exclude them.

Science.gov (United States)

Xu, Xiaolei; Yao, Shuxia; Xu, Lei; Geng, Yayuan; Zhao, Weihua; Ma, Xiaole; Kou, Juan; Luo, Ruixue; Kendrick, Keith M

2017-01-12

We normally react to individuals who exclude us socially by either avoiding them or increasing our attempts to interact with them. The neuropeptide oxytocin can promote social bonds and reduce social conflict and we therefore investigated whether it facilitates more positive social responses towards individuals who exclude or include us. In a double-blind, placebo-controlled, between-subject design 77 healthy Chinese male and female participants received intranasal oxytocin (40 IU) or placebo before playing a modified virtual ball-tossing game with three fictitious partners who either showed exclusion, inclusion or neutral behavioral interactions with them. Results showed that both male and female subjects threw the ball more often to individuals who excluded rather than included them, although oxytocin did not alter this or awareness/feelings of exclusion or inclusion. However, when subjects returned a week later males, but not females, in the oxytocin group exhibited an increased liking for, and preference for playing again with, players who had previously excluded them. This oxytocin effect was positively associated with independent traits. Our findings suggest that in a collectivist culture oxytocin may promote the desire of males, but not females, with a stronger independent orientation to rebuild social connections with individuals who have previously excluded them.

NNDSS - Table II. Salmonellosis (excluding typhoid fever and paratyphoid fever) to Shigellosis

Data.gov (United States)

U.S. Department of Health & Human Services — NNDSS - Table II. Salmonellosis (excluding typhoid fever and paratyphoid fever) to Shigellosis - 2018. In this Table, provisional cases of selected notifiable...

Portable XRF on Prehistoric Bronze Artefacts: Limitations and Use for the Detection of Bronze Age Metal Workshops

DEFF Research Database (Denmark)

Nørgaard, Heide Wrobel

2017-01-01

sections were analysed using a scanning electron microscope (SEM). Results from the corrosion crust of copper-tin alloys, and the change measured within the elemental composition from the bulk metal to the surface, greatly influenced the interpretation of the second data set, which was measured using......Two different scientific analyses—one destructive and one non destructive—were conducted on two separate groups of bronze ornaments dating from 1500–1100 BC to investigate, amongst other traits, the metal composition of their copper-tin alloys. One group of artefacts was sampled, and polished thin...... a handheld X-ray fluorescence (XRF) device. The surface of corroded bronze ornaments consists mostly of copper carbonates, oxides, and chlorides. Chemical processes, such as decuprification, change the element composition in such a manner that the original alloy cannot be traced with a non-destructive method...

Comparative Laser Spectroscopy Diagnostics for Ancient Metallic Artefacts Exposed to Environmental Pollution

Directory of Open Access Journals (Sweden)

Łukasz Ciupiński

2010-05-01

Full Text Available Metal artworks are subjected to corrosion and oxidation processes due to reactive agents present in the air, water and in the ground that these objects have been in contact with for hundreds of years. This is the case for archaeological metals that are recovered from excavation sites, as well as artefacts exposed to polluted air. Stabilization of the conservation state of these objects needs precise diagnostics of the accrued surface layers and identification of original, historical materials before further protective treatments, including safe laser cleaning of unwanted layers. This paper presents analyses of the chemical composition and stratigraphy of corrosion products with the use of laser induced breakdown spectroscopy (LIBS and Raman spectroscopy. The discussion of the results is supported by material studies (SEM-EDS, XRF, ion-analyses. The tests were performed on several samples taken from original objects, including copper roofing from Wilanów Palace in Warsaw and Karol Poznański Palace in Łódź, bronze decorative figures from the Wilanów Palace gardens, and four archaeological examples of old jewellery (different copper alloys. Work has been performed as a part of the MATLAS project in the frames of EEA and Norway Grants (www.matlas.eu and the results enable the comparison of the methodology and to elaborate the joint diagnostic procedures of the three project partner independent laboratories.

Comparative Laser Spectroscopy Diagnostics for Ancient Metallic Artefacts Exposed to Environmental Pollution

Science.gov (United States)

Ciupiński, Łukasz; Fortuna-Zaleśna, Elżbieta; Garbacz, Halina; Koss, Andrzej; Kurzydłowski, Krzysztof J.; Marczak, Jan; Mróz, Janusz; Onyszczuk, Tomasz; Rycyk, Antoni; Sarzyński, Antoni; Skrzeczanowski, Wojciech; Strzelec, Marek; Zatorska, Anna; Żukowska, Grażyna Z.

2010-01-01

Metal artworks are subjected to corrosion and oxidation processes due to reactive agents present in the air, water and in the ground that these objects have been in contact with for hundreds of years. This is the case for archaeological metals that are recovered from excavation sites, as well as artefacts exposed to polluted air. Stabilization of the conservation state of these objects needs precise diagnostics of the accrued surface layers and identification of original, historical materials before further protective treatments, including safe laser cleaning of unwanted layers. This paper presents analyses of the chemical composition and stratigraphy of corrosion products with the use of laser induced breakdown spectroscopy (LIBS) and Raman spectroscopy. The discussion of the results is supported by material studies (SEM-EDS, XRF, ion-analyses). The tests were performed on several samples taken from original objects, including copper roofing from Wilanów Palace in Warsaw and Karol Poznański Palace in ŁódŸ, bronze decorative figures from the Wilanów Palace gardens, and four archaeological examples of old jewellery (different copper alloys). Work has been performed as a part of the MATLAS project in the frames of EEA and Norway Grants (www.matlas.eu) and the results enable the comparison of the methodology and to elaborate the joint diagnostic procedures of the three project partner independent laboratories. PMID:22399915

Only MR can safely exclude patients from arthroscopy

International Nuclear Information System (INIS)

Vincken, Patrice W.J.; Braak, Bert P.M. ter; Erkel, Arian R. van; Bloem, Johan L.; Bloem, Rolf M.; Luijt, Peter A. van; Coene, L.N.J.E.M.; Lange, Sam de

2009-01-01

The aim of this study was to determine in patients with subacute knee complaints and normal standardized physical examination the fraction of magnetic resonance imaging (MRI) studies showing arthroscopically treatable intra-articular pathology. There were 290 consecutive patients (between 16 and 45 years) with at least 4 weeks of knee complaints and low clinical suspicion of intra-articular pathology based on physical exam. Two hundred seventy-four patients were included. Sixteen patients with prior knee surgery, rheumatic arthritis, or severe osteoarthritis were excluded. MRI was used to assign patients to group 1 (treatable abnormalities) or group 2 (normal or no treatable findings), depending on whether MR demonstrated treatable pathology. Arthroscopy was performed in group 1 patients. If symptoms persisted for 3 months in group 2 patients, cross over to arthroscopy was allowed. MR showed treatable pathology in 73 patients (26.6%). Arthroscopy was performed in 64 patients of 73 patients (group 1). In 52 patients (81.3%, 95% confidence interval (CI) 71.4-91.1%), arthroscopy was therapeutic. Of the 13 arthroscopies (6.5%) in group 2, four were therapeutic (30.8%, 95% CI 1.7-59.8). The highest fraction of MR studies showing treatable pathology was found in males, aged over 30 years, with a history of effusion (54.5%, six of 11 patients). Authors believe that the negative predictive value of clinical assessment in patients with subacute knee complaints is too low to exclude these patients from MR. MR should at least be considered in male patients aged 30 years and over with a history of effusion. (orig.)

Only MR can safely exclude patients from arthroscopy

Energy Technology Data Exchange (ETDEWEB)

Vincken, Patrice W.J.; Braak, Bert P.M. ter; Erkel, Arian R. van; Bloem, Johan L. [Leiden University Medical Center, Department of Radiology, P.O. Box 9600, Leiden (Netherlands); Bloem, Rolf M. [Leiden University Medical Center, Department of Orthopedic Surgery, Leiden (Netherlands); Reinier de Graaf Gasthuis, Department of Orthopedic Surgery, Delft (Netherlands); Luijt, Peter A. van [Leiden University Medical Center, Department of Traumatology, Leiden (Netherlands); Coene, L.N.J.E.M. [HAGA Hospital, Department of Orthopaedic Surgery, The Hague (Netherlands); Lange, Sam de [Medical Center Haaglanden, Department of Orthopedic Surgery, The Hague (Netherlands)

2009-10-15

The aim of this study was to determine in patients with subacute knee complaints and normal standardized physical examination the fraction of magnetic resonance imaging (MRI) studies showing arthroscopically treatable intra-articular pathology. There were 290 consecutive patients (between 16 and 45 years) with at least 4 weeks of knee complaints and low clinical suspicion of intra-articular pathology based on physical exam. Two hundred seventy-four patients were included. Sixteen patients with prior knee surgery, rheumatic arthritis, or severe osteoarthritis were excluded. MRI was used to assign patients to group 1 (treatable abnormalities) or group 2 (normal or no treatable findings), depending on whether MR demonstrated treatable pathology. Arthroscopy was performed in group 1 patients. If symptoms persisted for 3 months in group 2 patients, cross over to arthroscopy was allowed. MR showed treatable pathology in 73 patients (26.6%). Arthroscopy was performed in 64 patients of 73 patients (group 1). In 52 patients (81.3%, 95% confidence interval (CI) 71.4-91.1%), arthroscopy was therapeutic. Of the 13 arthroscopies (6.5%) in group 2, four were therapeutic (30.8%, 95% CI 1.7-59.8). The highest fraction of MR studies showing treatable pathology was found in males, aged over 30 years, with a history of effusion (54.5%, six of 11 patients). Authors believe that the negative predictive value of clinical assessment in patients with subacute knee complaints is too low to exclude these patients from MR. MR should at least be considered in male patients aged 30 years and over with a history of effusion. (orig.)

Psychiatric Disorder or Impairing Psychology in Children Who Have Been Excluded from School: A Systematic Review

Science.gov (United States)

Whear, Rebecca; Marlow, Ruth; Boddy, Kate; Ukoumunne, Obioha C.; Parker, Claire; Ford, Tamsin; Thompson-Coon, Jo; Stein, Ken

2014-01-01

When children with special educational needs are excluded from school, it should raise the concern that these children are not receiving adequate help and support. This systematic review aims to identify the prevalence of psychiatric disorder or impairing psychopathology among children who are excluded from school compared to children who are not…

A comparison of prone SPET and left lateral (decubitus) planar imaging for inferior wall attenuation artefact in 201Tl myocardial imaging

International Nuclear Information System (INIS)

O'Donnell, M.; Jenkin, B.; Van Every, B.; Kelly, M.J.; Kalff, V.

1999-01-01

Full text: Inferior wall attenuation artefacts are a major problem in supine SPET (S-S) myocardial perfusion imaging. SPET imaging with the patient lying in the prone position (P-S) and left lateral planar imaging with the patient lying in the right lateral decubitus position (LL) ameliorate this artefact. This study attempts to define the clinical role of P-S and LL imaging in characterizing S-S inferior wall defects. 21 patients with an inferior wall defect on S-S then had LL and rapid P-S imaging. All images were performed with a GE Optima NX gamma camera using GENIE acquisition and processing. All SPETs used 16 stops (32 frames) through 90 deg, with 40 s per stop for SS and 14 s per stop for P-S. LL images were acquired for 150 s. All images were assessed for adequacy and inferior wall scored for 0 = no, 1 mild, 2 moderate and 3 = severe defects. Statistical analysis was performed using the Wilcoxon rank sum test for matched pairs. All images were adequate for analysis. Significantly fewer defects were seen in P-S vs S-S, LL vs S-S (P 0.88); however; there was a difference (P < 0.05) in the subgroup (n = 7) with moderate defects on S-S imaging but no LL defect. In conclusion, most inferior wall defects seen on S-S imaging can be attributed to either attenuation or true perfusion defects with the use of LL imaging. Prone imaging may only be helpful where the inferior defect is of moderate severity but no LL defect is seen

Independent component analysis-based artefact reduction: application to the electrocardiogram for improved magnetic resonance imaging triggering

International Nuclear Information System (INIS)

Oster, Julien; Pietquin, Olivier; Felblinger, Jacques; Abächerli, Roger; Kraemer, Michel

2009-01-01

Electrocardiogram (ECG) is required during magnetic resonance (MR) examination for monitoring patients under anaesthesia or with heart diseases and for synchronizing image acquisition with heart activity (triggering). Accurate and fast QRS detection is therefore desirable, but this task is complicated by artefacts related to the complex MR environment (high magnetic field, radio-frequency pulses and fast switching magnetic gradients). Specific signal processing has been proposed, whether using specific MR QRS detectors or ECG denoising methods. Most state-of-the-art techniques use a connection to the MR system for achieving their task, which is a major drawback since access to the MR system is often restricted. This paper introduces a new method for on-line ECG signal enhancement, called ICARE, which takes advantage of using multi-lead ECG and does not require any connection to the MR system. It is based on independent component analysis (ICA) and applied in real time. This algorithm yields accurate QRS detection for efficient triggering

Coil–globule transition of a polymer involved in excluded-volume interactions with macromolecules

International Nuclear Information System (INIS)

Odagiri, Kenta; Seki, Kazuhiko

2015-01-01

Polymers adopt extended coil and compact globule states according to the balance between entropy and interaction energies. The transition of a polymer between an extended coil state and compact globule state can be induced by changing thermodynamic force such as temperature to alter the energy/entropy balance. Previously, this transition was theoretically studied by taking into account the excluded-volume interaction between monomers of a polymer chain using the partition function. For binary mixtures of a long polymer and short polymers, the coil-globule transition can be induced by changing the concentration of the shorter polymers. Here, we investigate the transition caused by short polymers by generalizing the partition function of the long polymer to include the excluded-volume effect of short polymers. The coil-globule transition is studied as a function of the concentration of mixed polymers by systematically varying Flory’s χ-parameters. We show that the transition is caused by the interplay between the excluded-volume interaction and the dispersion state of short polymers in the solvent. We also reveal that the same results can be obtained by combining the mixing entropy and elastic energy if the volume of a long polymer is properly defined

Irradiation treatment for the protection and conservation of cultural heritage artefacts in Croatia

International Nuclear Information System (INIS)

Katusin-Razem, Branka; Razem, Dusan; Braun, Mario

2009-01-01

The application of irradiation treatment for the protection of cultural heritage artefacts in Croatia was made possible by the development of radiation processing procedures at the Radiation Chemistry and Dosimetry Laboratory of the Ruder Boskovic Institute. After the upgrading of the 60 Co gamma irradiation source in the panoramic irradiation facility in 1983 it became possible to perform both research and pilot plant-scale irradiations for sterilization, pasteurization and decontamination of various materials, including medical supplies, pharmaceuticals, cosmetics and foods, but also for disinfestation of cultural heritage artefects. The demand for irradiation treatment of cultural heritage objects has particularly increased as the increasing number of these objects, especially polychromic wooden sculptures, were requiring salvation, restauration and conservation as a consequence of direct and indirect damages inflicted to them during the war in Croatia, 1991-1995. The irradiation facility at the Ruder Boskovic Institute is briefly described and an account of its fifteen years' activities in the irradiation treatment of cultural heritage objects is given. Some case studies performed in cooperation with the Croatian Conservation Institute and other interested parties are presented, as well as some cases of protective and curative treatments for disinfestation and decontamination. International cooperations and activities are also mentioned.

Irradiation treatment for the protection and conservation of cultural heritage artefacts in Croatia

Energy Technology Data Exchange (ETDEWEB)

Katusin-Razem, Branka [Department of Chemistry, Ruder Boskovic Institute, Bijenicka cesta 54, P.O. Box 180, HR-10002 Zagreb (Croatia)], E-mail: brazem@irb.hr; Razem, Dusan [Department of Chemistry, Ruder Boskovic Institute, Bijenicka cesta 54, P.O. Box 180, HR-10002 Zagreb (Croatia); Braun, Mario [Croatian Conservation Institute, Zagreb (Croatia)

2009-07-15

The application of irradiation treatment for the protection of cultural heritage artefacts in Croatia was made possible by the development of radiation processing procedures at the Radiation Chemistry and Dosimetry Laboratory of the Ruder Boskovic Institute. After the upgrading of the {sup 60}Co gamma irradiation source in the panoramic irradiation facility in 1983 it became possible to perform both research and pilot plant-scale irradiations for sterilization, pasteurization and decontamination of various materials, including medical supplies, pharmaceuticals, cosmetics and foods, but also for disinfestation of cultural heritage artefects. The demand for irradiation treatment of cultural heritage objects has particularly increased as the increasing number of these objects, especially polychromic wooden sculptures, were requiring salvation, restauration and conservation as a consequence of direct and indirect damages inflicted to them during the war in Croatia, 1991-1995. The irradiation facility at the Ruder Boskovic Institute is briefly described and an account of its fifteen years' activities in the irradiation treatment of cultural heritage objects is given. Some case studies performed in cooperation with the Croatian Conservation Institute and other interested parties are presented, as well as some cases of protective and curative treatments for disinfestation and decontamination. International cooperations and activities are also mentioned.

40 CFR 725.910 - Persons excluded from reporting significant new uses.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Persons excluded from reporting significant new uses. 725.910 Section 725.910 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... designated significant new uses, or (2) That the recipient has knowledge of the specific section in subpart M...

Clarifying the use of aggregated exposures in multilevel models: self-included vs. self-excluded measures.

Directory of Open Access Journals (Sweden)

Etsuji Suzuki

Full Text Available Multilevel analyses are ideally suited to assess the effects of ecological (higher level and individual (lower level exposure variables simultaneously. In applying such analyses to measures of ecologies in epidemiological studies, individual variables are usually aggregated into the higher level unit. Typically, the aggregated measure includes responses of every individual belonging to that group (i.e. it constitutes a self-included measure. More recently, researchers have developed an aggregate measure which excludes the response of the individual to whom the aggregate measure is linked (i.e. a self-excluded measure. In this study, we clarify the substantive and technical properties of these two measures when they are used as exposures in multilevel models.Although the differences between the two aggregated measures are mathematically subtle, distinguishing between them is important in terms of the specific scientific questions to be addressed. We then show how these measures can be used in two distinct types of multilevel models-self-included model and self-excluded model-and interpret the parameters in each model by imposing hypothetical interventions. The concept is tested on empirical data of workplace social capital and employees' systolic blood pressure.Researchers assume group-level interventions when using a self-included model, and individual-level interventions when using a self-excluded model. Analytical re-parameterizations of these two models highlight their differences in parameter interpretation. Cluster-mean centered self-included models enable researchers to decompose the collective effect into its within- and between-group components. The benefit of cluster-mean centering procedure is further discussed in terms of hypothetical interventions.When investigating the potential roles of aggregated variables, researchers should carefully explore which type of model-self-included or self-excluded-is suitable for a given situation

Excluding black hole firewalls with extreme cosmic censorship

Energy Technology Data Exchange (ETDEWEB)

Page, Don N., E-mail: profdonpage@gmail.com [Department of Physics, 4-183 CCIS, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada)

2014-06-01

The AMPS argument for black hole firewalls seems to arise not only from the assumption of local effective field theory outside the stretched horizon but also from an overcounting of internal black hole states that include states that are singular in the past. Here I propose to exclude such singular states by Extreme Cosmic Censorship (the conjectured principle that the universe is entirely nonsingular, except for transient singularities inside black and/or white holes). I argue that the remaining set of nonsingular realistic states do not have firewalls but yet preserve information in Hawking radiation from black holes that form from nonsingular initial states.

Excluding black hole firewalls with extreme cosmic censorship

International Nuclear Information System (INIS)

Page, Don N.

2014-01-01

The AMPS argument for black hole firewalls seems to arise not only from the assumption of local effective field theory outside the stretched horizon but also from an overcounting of internal black hole states that include states that are singular in the past. Here I propose to exclude such singular states by Extreme Cosmic Censorship (the conjectured principle that the universe is entirely nonsingular, except for transient singularities inside black and/or white holes). I argue that the remaining set of nonsingular realistic states do not have firewalls but yet preserve information in Hawking radiation from black holes that form from nonsingular initial states

Nanoparticles of Sr(OH)2: synthesis in homogeneous phase at low temperature and application for cultural heritage artefacts

International Nuclear Information System (INIS)

Ciliberto, E.; Condorelli, G.G.; La Delfa, S.; Viscuso, E.

2008-01-01

This paper concerns the synthesis and the characterization of nanometer particles of Sr(OH) 2 , a moderately high water soluble hydroxide (Ksp=3.2 x 10 -4 at 25 C). The reported process yields strontium hydroxide nanoparticles starting from low cost raw materials in aqueous medium (homogeneous phase) at low temperature (below 100 C) by chemical precipitation from salt solutions, involving very simple operational steps and avoiding the use of organic solvents. Observations by X-ray diffraction (XRD), scanning electron microscopy (SEM), electron dispersive X-Ray (EDX) and Fourier transform infrared spectroscopy (FTIR) indicate that the particles are well-crystallized and have nanometer dimensions (∝30 nm in diameter). Moreover, experimental evidence shows the potential use of this material for the protection and the consolidation of wall paintings (frescoes), paper, stone, wood and other artistic artefacts. (orig.)

The artefacts of radiochromic film dosimetry with flatbed scanners and their causation by light scattering from radiation-induced polymers

International Nuclear Information System (INIS)

Schoenfeld, Andreas A; Poppinga, Daniela; Poppe, Bjoern; Harder, Dietrich; Doerner, Karl-Joachim

2014-01-01

Optical experiments and theoretical considerations have been undertaken in order to understand the causes of the ‘orientation effect’ and the ‘parabola effect’, the artefacts impairing the desired light absorption measurement on radiochromic EBT3 films with flatbed scanners. EBT3 films exposed to doses up to 20.9 Gy were scanned with an Epson Expression 10000XL flatbed scanner in landscape and portrait orientation. The horizontally and vertically polarized light components of the scanner were determined, and another Epson Expression 10000XL flatbed scanner was disassembled to examine its optical components. The optical properties of exposed and unexposed EBT3 films were studied with incident polarized and unpolarized white light, and the transmitted red light was investigated for its polarization and scattering properties including the distribution of the scattering angles. Neutral density filters were studied for comparison. Guidance was sought from the theory of light scattering from rod-like macromolecular structures. The drastic dose-dependent variation of the transmitted total light current as function of the orientation of front and rear polarizers, interpreted by light scattering theory, shows that the radiation-induced polymerization of the monomers of EBT3 films produces light scattering oscillators preferably polarized at right angles with the coating direction of the film. The directional distribution of the scattered light is partly anisotropic, with a preferred scattering plane at right angles with the coating direction, indicating light scattering from stacks of coherently vibrating oscillators piled up along the monomer crystals. The polyester carrier film also participates in these effects. The ‘orientation’ and ‘parabola’ artefacts due to flatbed scanning of radiochromic films can be explained by the interaction of the polarization-dependent and anisotropic light scattering from exposed and unexposed EBT3 films with the quantitative

20 CFR 30.718 - How is a provider notified of OWCP's intent to exclude him or her?

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false How is a provider notified of OWCP's intent to exclude him or her? 30.718 Section 30.718 Employees' Benefits OFFICE OF WORKERS' COMPENSATION... OWCP's intent to exclude him or her? The Regional Director shall initiate the exclusion process by...

20 CFR 10.818 - How is a provider notified of OWCP's intent to exclude him or her?

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false How is a provider notified of OWCP's intent to exclude him or her? 10.818 Section 10.818 Employees' Benefits OFFICE OF WORKERS' COMPENSATION... How is a provider notified of OWCP's intent to exclude him or her? The Regional Director shall...

[Marshmallow for investigating functional disturbances of the esophageal body].

Science.gov (United States)

Keren, S; Argaman, E

1992-09-01

Manometric studies using water boluses do not always demonstrate disturbances in esophageal motility. We tested the use of a marshmallow bolus to induce abnormal manometric patterns in patients with dysphagia in whom manometric studies using water boluses were normal or nearly so. The study group included 12 normal volunteers and 22 patients with dysphagia and nearly normal manometric studies. Pressure was recorded along the esophageal body using 10 "wet" swallows followed by 10 "solid" swallows of marshmallow. In normal subjects there were fewer abnormal contractions after solid swallows than after wet swallows. In 15 patients solid swallows induced abnormal motility patterns which were not observed after wet swallows. The probability of inducing abnormal contractions in patients after solid swallows is significantly greater than after wet swallows (p < 0.0001). Solid swallowing is therefore useful in evaluating functional disturbances of the esophagus in patients with dysphagia.

Breast MRI used as a problem-solving tool reliably excludes malignancy

International Nuclear Information System (INIS)

Spick, Claudio; Szolar, Dieter H.M.; Preidler, Klaus W.; Tillich, Manfred; Reittner, Pia; Baltzer, Pascal A.

2015-01-01

Highlights: • Breast MRI reliably excludes malignancy in conventional BI-RADS 0 cases (NPV: 100%). • Malignancy rate in the BI-RADS 0 population is substantial with 13.5%. • Breast MRI used as a problem-solving tool reliably excludes malignancy. - Abstract: Purpose: To evaluate the diagnostic performance of breast MRI if used as a problem-solving tool in BI-RADS 0 cases. Material and methods: In this IRB-approved, single-center study, 687 women underwent high-resolution-3D, dynamic contrast-enhanced breast magnetic resonance imaging (MRI) between January 2012 and December 2012. Of these, we analyzed 111 consecutive patients (mean age, 51 ± 12 years; range, 20–83 years) categorized as BI-RADS 0. Breast MRI findings were stratified by clinical presentations, conventional imaging findings, and breast density. MRI results were compared to the reference standard, defined as histopathology or an imaging follow-up of at least 1 year. Results: One hundred eleven patients with BI-RADS 0 conventional imaging findings revealed 30 (27%) mammographic masses, 57 (51.4%) mammographic architectural distortions, five (4.5%) mammographic microcalcifications, 17 (15.3%) ultrasound-only findings, and two palpable findings without imaging correlates. There were 15 true-positive, 85 true-negative, 11 false-positive, and zero false-negative breast MRI findings, resulting in a sensitivity, specificity, PPV, and NPV of 100% (15/15), 88.5% (85/96), 57.7% (15/26), and 100% (85/85), respectively. Breast density and reasons for referral had no significant influence on the diagnostic performance of breast MRI (p > 0.05). Conclusion: Breast MRI reliably excludes malignancy in conventional BI-RADS 0 cases resulting in a NPV of 100% (85/85) and a PPV of 57.7% (15/26)

Excluded from School: Getting a Second Chance at a "Meaningful" Education

Science.gov (United States)

McGregor, Glenda; Mills, Martin; te Riele, Kitty; Hayes, Debra

2015-01-01

In this paper, we draw upon the experiences of a group of young people who have been excluded from mainstream schools in two Australian states to provide an account of the ways in which they have found their way to education in educational sites that are variously referred to as "flexible learning centres", "second chance…

On the equivalence of generalized least-squares approaches to the evaluation of measurement comparisons

Science.gov (United States)

Koo, A.; Clare, J. F.

2012-06-01

Analysis of CIPM international comparisons is increasingly being carried out using a model-based approach that leads naturally to a generalized least-squares (GLS) solution. While this method offers the advantages of being easier to audit and having general applicability to any form of comparison protocol, there is a lack of consensus over aspects of its implementation. Two significant results are presented that show the equivalence of three differing approaches discussed by or applied in comparisons run by Consultative Committees of the CIPM. Both results depend on a mathematical condition equivalent to the requirement that any two artefacts in the comparison are linked through a sequence of measurements of overlapping pairs of artefacts. The first result is that a GLS estimator excluding all sources of error common to all measurements of a participant is equal to the GLS estimator incorporating all sources of error, including those associated with any bias in the standards or procedures of the measuring laboratory. The second result identifies the component of uncertainty in the estimate of bias that arises from possible systematic effects in the participants' measurement standards and procedures. The expression so obtained is a generalization of an expression previously published for a one-artefact comparison with no inter-participant correlations, to one for a comparison comprising any number of repeat measurements of multiple artefacts and allowing for inter-laboratory correlations.

The Effect of Race in Patients with Achalasia Diagnosed With High-Resolution Esophageal Manometry.

Science.gov (United States)

Chedid, Victor; Rosenblatt, Elizabeth; Gandhi, Kunjal Komal; Dhalla, Sameer; Nandwani, Monica C; Stein, Ellen M; Clarke, John O

2018-02-01

The advent of the Chicago Classification for esophageal motility disorders allowed for clinically reproducible subgrouping of patients with achalasia based on manometric phenotype. However, there are limited data with regards to racial variation using high-resolution esophageal manometry (HREM). The aim of our study was to evaluate the racial differences in patients with achalasia diagnosed with HREM using the Chicago Classification. We evaluated the clinical presentation, treatment decisions and outcomes between blacks and non-blacks with achalasia to identify potential racial disparities. We performed a retrospective review of consecutive patients referred for HREM at a single tertiary referral center from June 2008 through October 2012. All patients diagnosed with achalasia on HREM according to the Chicago Classification were included. Demographic, clinical and manometric data were abstracted. All studies interpreted before the Chicago Classification was in widespread use were reanalyzed. Race was defined as black or non-black. Patients who had missing data were excluded. Proportions were compared using chi-squared analysis and means were compared using the Student's t-test. A total of 1,268 patients underwent HREM during the study period, and 105 (8.3%) were manometrically diagnosed with achalasia (53% female, mean age: 53.8 ± 17.0 years) and also met the aforementioned inclusion and exclusion criteria. A higher percentage of women presented with achalasia in blacks as compared to whites or other races (P treatment decisions and treatment outcomes among blacks and non-blacks. Our study highlights possible racial differences between blacks and non-blacks, including a higher proportion of black women diagnosed with achalasia and most blacks presenting with dysphagia. There is possibly a meaningful interaction of race and sex in the development of achalasia that might represent genetic differences in its pathophysiology. Further prospective studies are required

Achalasia in the elderly patient: a comparative study

Directory of Open Access Journals (Sweden)

Rosana B. Schechter

2011-03-01

Full Text Available CONTEXT: Achalasia is a primary esophageal motor disorder secondary to the degeneration of ganglion cells of the inhibitory intramural myenteric plexus. It affects both sexes similarly and has two peaks of incidence, one in the 3rd to 4th decades of life and the other after 60 years of age. The effect of age on esophageal motility of patients with achalasia is not well known. Studies have shown that healthy older people, when compared to the young, have: a a lower number of ganglion cells in the intramural myenteric plexus; b a reduced normal relaxation of the lower esophageal sphincter; and c a reduced esophageal peristalsis. Thus, as both age and achalasia can produce comparable degenerative changes in the intramural myenteric plexus, it is possible that advanced age could be an important factor in enhancing the clinical and manometric abnormalities commonly found in patients with achalasia. OBJECTIVES: To compare the clinical, radiological and manometric findings in young as compared to elderly (>60 years old achalasia patients. METHODS: A retrospective study of a group of patients with untreated achalasia separated into young and elderly patients. Demographic, clinical, serology for Chagas' disease, radiological and manometric data were compared between these groups. The level of significance was P<0.05. RESULTS: The study included 105 patients, 52 young (25 M/27 F, mean age 40 years old and 53 elderly (21 M/32 F, mean age 70 years old. The elderly group had a higher prevalence of Chagas' disease (P = 0.004 and a lower pressure of the lower esophageal sphincter [26.4 mm Hg vs 31.9 mm Hg] P = 0.001, a difference that persisted when analyzed only elderly and young patients with idiopathic achalasia. Younger patients had a higher prevalence of heartburn (P = 0.001 and chest pain (P = 0.012 than the elderly. CONCLUSION: Elderly patients with achalasia had a lower esophageal sphincter pressure than the young, even when we excluded patients with

An Arithmetical Hierarchy of the Law of Excluded Middle and Related Principles

DEFF Research Database (Denmark)

Akama, Yohji; Berardi, Stefano; Hayashi, Susumu

2004-01-01

's Lemma, Post's Theorem, Excluded Middle for simply Existential and simply Universal statements, and many others.Our motivations are rooted in the experience of one of the authors with an extended program extraction and of another author with bound extraction from classical proofs....

Extended use of electronic health records by primary care physicians: Does the electronic health record artefact matter?

Science.gov (United States)

Raymond, Louis; Paré, Guy; Marchand, Marie

2017-04-01

The deployment of electronic health record systems is deemed to play a decisive role in the transformations currently being implemented in primary care medical practices. This study aims to characterize electronic health record systems from the perspective of family physicians. To achieve this goal, we conducted a survey of physicians practising in private clinics located in Quebec, Canada. We used valid responses from 331 respondents who were found to be representative of the larger population. Data provided by the physicians using the top three electronic health record software products were analysed in order to obtain statistically adequate sub-sample sizes. Significant differences were observed among the three products with regard to their functional capability. The extent to which each of the electronic health record functionalities are used by physicians also varied significantly. Our results confirm that the electronic health record artefact 'does matter', its clinical functionalities explaining why certain physicians make more extended use of their system than others.

40 CFR Table 4 to Subpart Jj of... - Pollutants Excluded From Use in Cleaning and Washoff Solvents

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Pollutants Excluded From Use in Cleaning and Washoff Solvents 4 Table 4 to Subpart JJ of Part 63 Protection of Environment ENVIRONMENTAL... Operations Pt. 63, Subpt. JJ, Table 4 Table 4 to Subpart JJ of Part 63—Pollutants Excluded From Use in...

29 CFR 794.110 - Activities excluded from the enterprise by the statute.

Science.gov (United States)

2010-07-01

... definition quoted in § 794.106. The definition distinguishes between the related activities performed through... fide independent contractor (for example, an independent accounting or auditing firm). The latter activities are expressly excluded from the “enterprise” as defined. In addition, the definition contains a...

TSH alone is not sufficient to exclude all patients with a functioning thyroid nodule from undergoing testing to exclude thyroid cancer

Energy Technology Data Exchange (ETDEWEB)

Hurtado-Lopez, Luis-Mauricio; Monroy-Lozano, Blanca-Estela [General Hospital of Mexico, Mexico City (Mexico); Martinez-Duncker, Carlos [Hospital Infantil de Mexico Federico Gomez, Medicina Nuclear Molecular, Mexico City, DF (Mexico)

2008-06-15

The purpose of the study was to analyze whether the thyroid-stimulating hormone (TSH) alone avoids tests to exclude malignancy in all patients with functional thyroid nodules (FTN). Sixty-nine patients with FTN on {sup 99m}Tc scintigraphy, radioiodine uptake test (RIU), {sup 99m}Tc thyroid uptake, TSH assay, T3, and T4 obtained within 48 h were retrospectively identified out of 2,356 thyroid scans performed from January 2000 to April 2007. FTNs were classified as causing total, partial, or no inhibition of the thyroid as group 1, 2, or 3, respectively. TSH was subnormal in 21 of 69 (30.43%) patients. In group 1 (N = 23, 33.3%), TSH was subnormal, normal, and high in eight, nine, and six patients; in group 2 (N = 17, 24.6%), TSH was subnormal, normal, and high in four, six, and seven patients, and in group 3 (N = 29, 42%), TSH was subnormal, normal, and high in 9, 13, and 7 patients, respectively. TSH was significantly lower in group 1. In T3, T4, {sup 99m}Tc thyroid uptake, and RIU, there were no differences between the three groups. Only 30.43% of patients had subnormal TSH. TSH alone cannot avoid tests to exclude malignancy in all patients with FTN. FTN existence can only be accurately assessed by thyroid scintigraphy. The current incidence of FTN may be unknown because scintigraphy is not routinely performed in all patients with thyroid nodules. Thyroid scintigraphy of patients with high TSH can detect diseases such as Hashimoto's thyroiditis and identify patients with FTN in whom no further diagnostic procedures would be needed in patients with normal TSH levels with nondiagnostic fine-needle aspiration results. (orig.)

Oxytocin biases men but not women to restore social connections with individuals who socially exclude them

OpenAIRE

Xu, Xiaolei; Yao, Shuxia; Xu, Lei; Geng, Yayuan; Zhao, Weihua; Ma, Xiaole; Kou, Juan; Luo, Ruixue; Kendrick, Keith M.

2017-01-01

We normally react to individuals who exclude us socially by either avoiding them or increasing our attempts to interact with them. The neuropeptide oxytocin can promote social bonds and reduce social conflict and we therefore investigated whether it facilitates more positive social responses towards individuals who exclude or include us. In a double-blind, placebo-controlled, between-subject design 77 healthy Chinese male and female participants received intranasal oxytocin (40 IU) or placebo...

9 CFR 130.19 - User fees for other veterinary diagnostic services or materials provided at NVSL (excluding FADDL).

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false User fees for other veterinary... User fees for other veterinary diagnostic services or materials provided at NVSL (excluding FADDL). (a) User fees for other veterinary diagnostic services or materials available from NVSL (excluding FADDL...

Effect of section shape on frequencies of natural oscillations of tubular springs

Science.gov (United States)

Pirogov, S. P.; Chuba, A. Yu; Cherentsov, D. A.

2018-05-01

The necessity of determining the frequencies of natural oscillations of manometric tubular springs is substantiated. Based on the mathematical model and computer program, numerical experiments were performed that allowed us to reveal the effect of geometric parameters on the frequencies of free oscillations of manometric tubular springs.

31 CFR 19.430 - How do I check to see if a person is excluded or disqualified?

Science.gov (United States)

2010-07-01

... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false How do I check to see if a person is excluded or disqualified? 19.430 Section 19.430 Money and Finance: Treasury Office of the Secretary of the... disqualified? You check to see if a person is excluded or disqualified in two ways: (a) You as an agency...

Nanoparticles of Sr(OH){sub 2}: synthesis in homogeneous phase at low temperature and application for cultural heritage artefacts

Energy Technology Data Exchange (ETDEWEB)

Ciliberto, E.; Condorelli, G.G.; La Delfa, S.; Viscuso, E. [Universita di Catania, Dipartimento di Scienze Chimiche, Catania (Italy)

2008-07-15

This paper concerns the synthesis and the characterization of nanometer particles of Sr(OH){sub 2}, a moderately high water soluble hydroxide (Ksp=3.2 x 10{sup -4} at 25 C). The reported process yields strontium hydroxide nanoparticles starting from low cost raw materials in aqueous medium (homogeneous phase) at low temperature (below 100 C) by chemical precipitation from salt solutions, involving very simple operational steps and avoiding the use of organic solvents. Observations by X-ray diffraction (XRD), scanning electron microscopy (SEM), electron dispersive X-Ray (EDX) and Fourier transform infrared spectroscopy (FTIR) indicate that the particles are well-crystallized and have nanometer dimensions ({proportional_to}30 nm in diameter). Moreover, experimental evidence shows the potential use of this material for the protection and the consolidation of wall paintings (frescoes), paper, stone, wood and other artistic artefacts. (orig.)

Liver stiffness plus platelet count can be used to exclude high-risk oesophageal varices.

Science.gov (United States)

Ding, Nik S; Nguyen, Tin; Iser, David M; Hong, Thai; Flanagan, Emma; Wong, Avelyn; Luiz, Lauren; Tan, Jonathan Y C; Fulforth, James; Holmes, Jacinta; Ryan, Marno; Bell, Sally J; Desmond, Paul V; Roberts, Stuart K; Lubel, John; Kemp, William; Thompson, Alexander J

2016-02-01

Endoscopic screening for high-risk gastro-oesophageal varices (GOV) is recommended for compensated cirrhotic patients with transient elastography identifying increasing numbers of patients with cirrhosis without portal hypertension. Using liver stiffness measurement (LSM) ± platelet count, the aim was to develop a simple clinical rule to exclude the presence of high-risk GOV in patients with Child-Pugh A cirrhosis. A retrospective analysis of 71 patients with Child-Pugh A cirrhosis diagnosed by transient elastography (LSM >13.6 kPa) who underwent screening gastroscopy was conducted. A predictive model using LSM ± platelet count was assessed to exclude the presence of high-risk GOV (diameter >5 mm and/or the presence of high-risk stigmata) and validated using a second cohort of 200 patients from two independent centres. High-risk GOV were present in 10 (15%) and 16 (8%) of the training and validation cohorts, respectively, which was associated with LSM and Pl count (P < 0.05). A combined model based on LSM and Pl count was more accurate for excluding the presence of high-risk GOV than either alone (training cohort AUROC: 0.87 [0.77-0.96] vs. 0.78 [0.65-0.92] for LSM and 0.71 [0.52-0.90] for platelets) with the combination of LSM ≤25 kPa and Pl ≥100 having a NPV of 100% in both the training and validation cohorts. A total of 107 (39%) patients meet this criterion. The combination of LSM ≤25 kPa and Pl ≥100 can be used in clinical practice to exclude the presence of high-risk GOV in patients with Child-Pugh A cirrhosis. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

9 CFR 130.16 - User fees for veterinary diagnostic serology tests performed at NVSL (excluding FADDL) or at...

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false User fees for veterinary diagnostic serology tests performed at NVSL (excluding FADDL) or at authorized sites. 130.16 Section 130.16 Animals... USER FEES § 130.16 User fees for veterinary diagnostic serology tests performed at NVSL (excluding...

Who's in and who's out: Labour law and those excluded from its ...

African Journals Online (AJOL)

The alternative is to challenge the divisions by organising the workers who are excluded at present. Significant gains can be made, it suggests, by working in parallel with other organisations, including those mobilising in the informal economy. The starting point, however, is in the workplaces where their own members are ...

24 CFR 203.18c - One-time or up-front mortgage insurance premium excluded from limitations on maximum mortgage...

Science.gov (United States)

2010-04-01

... insurance premium excluded from limitations on maximum mortgage amounts. 203.18c Section 203.18c Housing and...-front mortgage insurance premium excluded from limitations on maximum mortgage amounts. After... LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES SINGLE FAMILY MORTGAGE...

Performance Investigation of a Handheld 3d Scanner to Define Good Practices for Small Artefact 3d Modeling

Science.gov (United States)

Lachat, E.; Landes, T.; Grussenmeyer, P.

2017-08-01

Handheld 3D scanners can be used to complete large scale models with the acquisition of occluded areas or small artefacts. This may be of interest for digitization projects in the field of Cultural Heritage, where detailed areas may require a specific treatment. Such sensors present the advantage of being easily portable in the field, and easily usable even without particular knowledge. In this paper, the Freestyle3D handheld scanner launched on the market in 2015 by FARO is investigated. Different experiments are described, covering various topics such as the influence of range or color on the measurements, but also the precision achieved for geometrical primitive digitization. These laboratory experiments are completed by acquisitions performed on engraved and sculpted stone blocks. This practical case study is useful to investigate which acquisition protocol seems to be the more adapted and leads to precise results. The produced point clouds will be compared to photogrammetric surveys for the purpose of their accuracy assessment.

GUILT OF PERSONS WITH MENTAL DISORDERS ARE NOT EXCLUDING RESPONSIBILITIES

OpenAIRE

Ekaterina Valerievna Yurchak

2014-01-01

In the theory of law as a key cross-sectoral and multi-disciplinary institutions is the Institute of guilt. At the present stage of development of the law, in a convergence of many of its branches, it is important to investigate exhaustively the institution with the general legal position, both in general and in particular - the situation of the guilt of persons with mental disorder, not excluding sanity.The purpose of this study - to investigate the situation of the fault of persons with a m...

Technique for determining cesium-137 in milk excluding ashing

International Nuclear Information System (INIS)

Antonova, V.A.; Prokof'ev, O.N.

1984-01-01

For the purpose of simplification of the method of milk sample preparation for the radiochemical analysis for 137 Cs in laboratory sanitary and higienic investigations rapid analysis technique excluding sample ashing is developed. The technique comprises sample mixing with silica gel during an hour, 137 Cs desorption from silica gel into the 1N solution of hydrochloric acid, radiochemical analysis of hydrochloric solution for determining 137 Cs. The comparison of the results obtained by the above method and that with ashing provides perfect agreement. For taking into account the incompleteness of 137 Cs adsorption by silica gel a correction factor is applied in calculation formulae

HLA region excluded by linkage analyses of early onset periodontitis

Energy Technology Data Exchange (ETDEWEB)

Sun, C.; Wang, S.; Lopez, N.

1994-09-01

Previous studies suggested that HLA genes may influence susceptibility to early-onset periodontitis (EOP). Segregation analyses indicate that EOP may be due to a single major gene. We conducted linkage analyses to assess possible HLA effects on EOP. Fifty families with two or more close relatives affected by EOP were ascertained in Virginia and Chile. A microsatellite polymorphism within the HLA region (at the tumor necrosis factor beta locus) was typed using PCR. Linkage analyses used a donimant model most strongly supported by previous studies. Assuming locus homogeneity, our results exclude a susceptibility gene within 10 cM on either side of our marker locus. This encompasses all of the HLA region. Analyses assuming alternative models gave qualitatively similar results. Allowing for locus heterogeneity, our data still provide no support for HLA-region involvement. However, our data do not statistically exclude (LOD <-2.0) hypotheses of disease-locus heterogeneity, including models where up to half of our families could contain an EOP disease gene located in the HLA region. This is due to the limited power of even our relatively large collection of families and the inherent difficulties of mapping genes for disorders that have complex and heterogeneous etiologies. Additional statistical analyses, recruitment of families, and typing of flanking DNA markers are planned to more conclusively address these issues with respect to the HLA region and other candidate locations in the human genome. Additional results for markers covering most of the human genome will also be presented.

Quark-nuclear hybrid star equation of state with excluded volume effects

Science.gov (United States)

Kaltenborn, Mark Alexander Randolph; Bastian, Niels-Uwe Friedrich; Blaschke, David Bernhard

2017-09-01

A two-phase description of the quark-nuclear matter hybrid equation of state that takes into account the effect of excluded volume in both the hadronic and the quark-matter phases is introduced. The nuclear phase manifests a reduction of the available volume as density increases, leading to a stiffening of the matter. The quark-matter phase displays a reduction of the effective string tension in the confining density functional from available volume contributions. The nuclear equation of state is based upon the relativistic density-functional model DD2 with excluded volume. The quark-matter equation of state is based upon a quasiparticle model derived from a relativistic density-functional approach and will be discussed in greater detail. The interactions are decomposed into mean scalar and vector components. The scalar interaction is motivated by a string potential between quarks, whereas the vector interaction potential is motivated by higher-order interactions of quarks leading to an increased stiffening at high densities. As an application, we consider matter under compact star constraints of electric neutrality and β equilibrium. We obtain mass-radius relations for hybrid stars that form a third family, disconnected from the purely hadronic star branch, and fulfill the 2 M⊙ constraint.

Pigment identification on medieval manuscripts, paintings and other artefacts by Raman microscopy: applications to the study of three German manuscripts

Science.gov (United States)

Burgio, Lucia; Ciomartan, Dan A.; Clark, Robin J. H.

1997-03-01

The identification of the pigments used to illuminate medieval manuscripts, paintings and other artefacts has received a major boost recently through perceptive studies carried out by Raman microscopy. A brief summary of the background of the technique is given. The results of studies on three illuminated German manuscripts are presented. The pigments vermilion HgS, iron oxide Fe 2O 3, azurite 2CuCO 3.Cu(OH) 2, malachite CuCo 3.Cu(OH) 2, lampblack (essentially carbon), white lead 2PbCO 3.Pb(OH) 2, lead tin yellow type I Pb 2SnO 4, and lazurite Na 8[Al 6Si 6O 24]S n (but only in admixture with Pb 2SnO 4, whereby it forms a green pigment), have been identified on these manuscripts on the basis of Raman microscopy and the results discussed.

Registers of Artefacts of Creation—From the Late Medieval Period to the 19th Century

Directory of Open Access Journals (Sweden)

Chris Dent

2014-06-01

Full Text Available This paper offers a new perspective on the “development” of the intellectual property regimes in the United Kingdom. The system put in place under the 1875 Trade Marks Act may be seen as the last of a sequence of earlier “technologies” that sought to administer the creative endeavours of (sections of the English population. Prior to the trade mark registration (that included examination there was the registration of designs that did not require examination but was necessary for the protection of the right. In the eighteenth century, patent specifications were lodged with the Crown via a process that was much more involved than that was instituted for designs in the nineteenth century. Before that, books had to be enrolled with the Stationers’ Company before they could be printed. And, in what may be seen as an earlier attempt at the centralised regulation of artefacts of expression, the Rolls of Arms (maintained by the King of Arms was repository of coats of arms for English nobility. An exploration of these different technologies of regulation, in their socio-political context, will offer new insight into the antecedents, and limits, of the registration systems that are now common across the intellectual property world.

Wet-chemical etching of atom probe tips for artefact free analyses of nanoscaled semiconductor structures.

Science.gov (United States)

Melkonyan, D; Fleischmann, C; Veloso, A; Franquet, A; Bogdanowicz, J; Morris, R J H; Vandervorst, W

2018-03-01

We introduce an innovative specimen preparation method employing the selectivity of a wet-chemical etching step to improve data quality and success rates in the atom probe analysis of contemporary semiconductor devices. Firstly, on the example of an SiGe fin embedded in SiO 2 we demonstrate how the selective removal of SiO 2 from the final APT specimen significantly improves accuracy and reliability of the reconstructed data. With the oxide removal, we eliminate the origin of shape artefacts, i.e. the formation of a non-hemispherical tip shape, that are typically observed in the reconstructed volume of complex systems. Secondly, using the same approach, we increase success rates to ∼90% for the damage-free, 3D site-specific localization of short (250 nm), vertical Si nanowires at the specimen apex. The impact of the abrupt emitter radius change that is introduced by this specimen preparation method is evaluated as being minor using field evaporation simulation and comparison of different reconstruction schemes. The Ge content within the SiGe fin as well as the 3D boron distribution in the Si NW as resolved by atom probe analysis are in good agreement with TEM/EDS and ToF-SIMS analysis, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

Trust and cooperation in the public sphere: why Roma people should not be excluded?

Directory of Open Access Journals (Sweden)

Dragoş DRAGOMAN

2014-05-01

Full Text Available The recent political developments in Romania and other Central and East European countries, marked by rising populism and political extremism, shed light on the essential issue of building a free, tolerant and inclusive public sphere, which is willing to let arguments to be decisive instead of power, status, race or wealth. The current tendencies of socially excluding Roma, indiscriminately taken by populists for unjustified social burden and intolerable racial difference, are a warning for more radical political action that could undermine on the long-run the effort to set up a democratic public space. Excluding from start an entire minority would only encourage future exclusions based on ideology, ethnicity or religion, according to the narrow definition populists use to give to the concept of ‘people’.

Grafted polymers with annealed excluded volume : a model for surfactant association in brushes

NARCIS (Netherlands)

Currie, E.P.K.; Fleer, G.J.; Cohen Stuart, M.A.; Borisov, O.V.

2000-01-01

We present an analytical self-consistent-field (SCF) theory for a neutral polymer brush (a layer of long polymer chains end-grafted to a surface) with annealed excluded volume interactions between the monomer units. This model mimics the reversible adsorption of solute molecules or aggregates, such

Play It Again: Neural Responses to Reunion with Excluders Predicted by Attachment Patterns

Science.gov (United States)

White, Lars O.; Wu, Jia; Borelli, Jessica L.; Mayes, Linda C.; Crowley, Michael J.

2013-01-01

Reunion behavior following stressful separations from caregivers is often considered the single most sensitive clue to infant attachment patterns. Extending these ideas to middle childhood/early adolescence, we examined participants' neural responses to reunion with peers who had previously excluded them. We recorded event-related potentials…

Scintiscanning study of esophageal transit on the chronic chagasic esophagopaty

International Nuclear Information System (INIS)

Rezende Filho, J.

1985-01-01

The passage of a radionuclide labelled 10 ml liquid bolus through the esophagus was evaluated by a scintigraphic method in 13 normal subjects, 13 asymptomatic Chagas' disease patients, and 39 Chagas' disease patients with esophageal symptoms and/or radiological esophageal abnormalities. The manometric evaluation of esophagus was performed on 44 Chagas' disease patients by a standard manometric technique. (author)

20 CFR 668.650 - Can INA grantees exclude segments of the eligible population?

Science.gov (United States)

2010-04-01

... eligible population? 668.650 Section 668.650 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION... population? (a) No, INA grantees cannot exclude segments of the eligible population. INA grantees must document in their Two Year Plan that a system is in place to afford all members of the eligible population...

41 CFR 105-68.325 - What happens if I do business with an excluded person in a covered transaction?

Science.gov (United States)

2010-07-01

... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false What happens if I do business with an excluded person in a covered transaction? 105-68.325 Section 105-68.325 Public Contracts...-68.325 What happens if I do business with an excluded person in a covered transaction? If as a...

Notes on the Ebenaceae. VI. Four species to be excluded from the family

NARCIS (Netherlands)

Ng, F.S.P.

1970-01-01

In the course of a study on Indo-Malesian Ebenaceae currently being carried out in the Oxford Forest Herbarium, it has been discovered that four species previously accepted as Diospyros do not belong to that genus and must be excluded from the family. They are as follows. 1. Diospyros addita

Verification of Carbon Sink Assessment. Can We Exclude Natural Sinks?

International Nuclear Information System (INIS)

Alexandrov, G.; Yamagata, Y

2004-01-01

Any human-induced terrestrial sink is susceptible to the effects of elevated atmospheric CO2 concentration, nitrogen deposition, climate variability and other natural or indirect human-induced factors. It has been suggested in climate negotiations that the effects of these factors should be excluded from estimates of carbon sequestration used to meet the emission reduction commitments under the Kyoto Protocol. This paper focuses on the methodologies for factoring out the effects of atmospheric and climate variability/change. We estimate the relative magnitude of the non-human induced effects by using two biosphere models and discuss possibilities for narrowing estimate uncertainty

Model output: fact or artefact?

Science.gov (United States)

Melsen, Lieke

2015-04-01

As a third-year PhD-student, I relatively recently entered the wonderful world of scientific Hydrology. A science that has many pillars that directly impact society, for example with the prediction of hydrological extremes (both floods and drought), climate change, applications in agriculture, nature conservation, drinking water supply, etcetera. Despite its demonstrable societal relevance, hydrology is often seen as a science between two stools. Like Klemeš (1986) stated: "By their academic background, hydrologists are foresters, geographers, electrical engineers, geologists, system analysts, physicists, mathematicians, botanists, and most often civil engineers." Sometimes it seems that the engineering genes are still present in current hydrological sciences, and this results in pragmatic rather than scientific approaches for some of the current problems and challenges we have in hydrology. Here, I refer to the uncertainty in hydrological modelling that is often neglected. For over thirty years, uncertainty in hydrological models has been extensively discussed and studied. But it is not difficult to find peer-reviewed articles in which it is implicitly assumed that model simulations represent the truth rather than a conceptualization of reality. For instance in trend studies, where data is extrapolated 100 years ahead. Of course one can use different forcing datasets to estimate the uncertainty of the input data, but how to prevent that the output is not a model artefact, caused by the model structure? Or how about impact studies, e.g. of a dam impacting river flow. Measurements are often available for the period after dam construction, so models are used to simulate river flow before dam construction. Both are compared in order to qualify the effect of the dam. But on what basis can we tell that the model tells us the truth? Model validation is common nowadays, but validation only (comparing observations with model output) is not sufficient to assume that a

Sources of Artefacts in Synthetic Aperture Radar Interferometry Data Sets

Science.gov (United States)

Becek, K.; Borkowski, A.

2012-07-01

In recent years, much attention has been devoted to digital elevation models (DEMs) produced using Synthetic Aperture Radar Interferometry (InSAR). This has been triggered by the relative novelty of the InSAR method and its world-famous product—the Shuttle Radar Topography Mission (SRTM) DEM. However, much less attention, if at all, has been paid to sources of artefacts in SRTM. In this work, we focus not on the missing pixels (null pixels) due to shadows or the layover effect, but rather on outliers that were undetected by the SRTM validation process. The aim of this study is to identify some of the causes of the elevation outliers in SRTM. Such knowledge may be helpful to mitigate similar problems in future InSAR DEMs, notably the ones currently being developed from data acquired by the TanDEM-X mission. We analysed many cross-sections derived from SRTM. These cross-sections were extracted over the elevation test areas, which are available from the Global Elevation Data Testing Facility (GEDTF) whose database contains about 8,500 runways with known vertical profiles. Whenever a significant discrepancy between the known runway profile and the SRTM cross-section was detected, a visual interpretation of the high-resolution satellite image was carried out to identify the objects causing the irregularities. A distance and a bearing from the outlier to the object were recorded. Moreover, we considered the SRTM look direction parameter. A comprehensive analysis of the acquired data allows us to establish that large metallic structures, such as hangars or car parking lots, are causing the outliers. Water areas or plain wet terrains may also cause an InSAR outlier. The look direction and the depression angle of the InSAR system in relation to the suspected objects influence the magnitude of the outliers. We hope that these findings will be helpful in designing the error detection routines of future InSAR or, in fact, any microwave aerial- or space-based survey. The

SOURCES OF ARTEFACTS IN SYNTHETIC APERTURE RADAR INTERFEROMETRY DATA SETS

Directory of Open Access Journals (Sweden)

K. Becek

2012-07-01

Full Text Available In recent years, much attention has been devoted to digital elevation models (DEMs produced using Synthetic Aperture Radar Interferometry (InSAR. This has been triggered by the relative novelty of the InSAR method and its world-famous product—the Shuttle Radar Topography Mission (SRTM DEM. However, much less attention, if at all, has been paid to sources of artefacts in SRTM. In this work, we focus not on the missing pixels (null pixels due to shadows or the layover effect, but rather on outliers that were undetected by the SRTM validation process. The aim of this study is to identify some of the causes of the elevation outliers in SRTM. Such knowledge may be helpful to mitigate similar problems in future InSAR DEMs, notably the ones currently being developed from data acquired by the TanDEM-X mission. We analysed many cross-sections derived from SRTM. These cross-sections were extracted over the elevation test areas, which are available from the Global Elevation Data Testing Facility (GEDTF whose database contains about 8,500 runways with known vertical profiles. Whenever a significant discrepancy between the known runway profile and the SRTM cross-section was detected, a visual interpretation of the high-resolution satellite image was carried out to identify the objects causing the irregularities. A distance and a bearing from the outlier to the object were recorded. Moreover, we considered the SRTM look direction parameter. A comprehensive analysis of the acquired data allows us to establish that large metallic structures, such as hangars or car parking lots, are causing the outliers. Water areas or plain wet terrains may also cause an InSAR outlier. The look direction and the depression angle of the InSAR system in relation to the suspected objects influence the magnitude of the outliers. We hope that these findings will be helpful in designing the error detection routines of future InSAR or, in fact, any microwave aerial- or space

The Structure of Artefacts of Management Control in the Innovation Process: Does Exist Association with the Strategic Profile?

Directory of Open Access Journals (Sweden)

Fábio Frezatti

2015-01-01

Full Text Available This study investigates what is the role of strateg ic profiles and management control instruments in organisations’ innovation process. B ased in a survey using structural equation modelling (121 companies, we confirm that analyser , defender e prospector profiles are associated with strategic planning, balanced scorec ard (BSC and rolling forecast. The reactor type is associated with lower use of artefacts. Our results confirm the linkage between incremental innovation and strategic planning and b etween radical innovation and BSC. These findings reflect the alignment between strate gic types, the availability of instruments and intensity of innovation, which is useful inform ation with which to understand organisations and their market activities. This pap er bring information about specific management control instruments existence and the im pact for the intensity of the innovation that is relevant for management and must stimulate organizations to be consistent in the cases that the strategic profile is a clear long term def inition or see the possibility of change when it is not the desired one.

The effect of excluding juveniles on apparent adult olive baboons (Papio anubis) social networks

Science.gov (United States)

Fedurek, Piotr; Lehmann, Julia

2017-01-01

In recent years there has been much interest in investigating the social structure of group living animals using social network analysis. Many studies so far have focused on the social networks of adults, often excluding younger, immature group members. This potentially may lead to a biased view of group social structure as multiple recent studies have shown that younger group members can significantly contribute to group structure. As proof of the concept, we address this issue by investigating social network structure with and without juveniles in wild olive baboons (Papio anubis) at Gashaka Gumti National Park, Nigeria. Two social networks including all independently moving individuals (i.e., excluding dependent juveniles) were created based on aggressive and grooming behaviour. We used knockout simulations based on the random removal of individuals from the network in order to investigate to what extent the exclusion of juveniles affects the resulting network structure and our interpretation of age-sex specific social roles. We found that juvenile social patterns differed from those of adults and that the exclusion of juveniles from the network significantly altered the resulting overall network structure. Moreover, the removal of juveniles from the network affected individuals in specific age-sex classes differently: for example, including juveniles in the grooming network increased network centrality of adult females while decreasing centrality of adult males. These results suggest that excluding juveniles from the analysis may not only result in a distorted picture of the overall social structure but also may mask some of the social roles of individuals belonging to different age-sex classes. PMID:28323851

Identification of the earliest collagen- and plant-based coatings from Neolithic artefacts (Nahal Hemar cave, Israel).

Science.gov (United States)

Solazzo, Caroline; Courel, Blandine; Connan, Jacques; van Dongen, Bart E; Barden, Holly; Penkman, Kirsty; Taylor, Sheila; Demarchi, Beatrice; Adam, Pierre; Schaeffer, Philippe; Nissenbaum, Arie; Bar-Yosef, Ofer; Buckley, Michael

2016-08-09

Mortuary practices in human evolution record cognitive, social changes and technological innovations. The Neolithic Revolution in the Levant was a watershed in this domain that has long fascinated the archaeological community. Plaster modelled skulls are well known at Jericho and several other Neolithic sites, and in Nahal Hemar cave (Israel, ca. 8200 -7300 cal. BC) excavations yielded six unique human skulls covered with a black organic coating applied in a net pattern evoking a headdress. This small cave was used as storage for paraphernalia in the semi-arid area of the Judean desert and the dry conditions preserved other artefacts such as baskets coated with a similar dark substance. While previous analysis had revealed the presence of amino acids consistent with a collagen signature, in the present report, specific biomarkers were characterised using combined proteomic and lipid approaches. Basket samples yielded collagen and blood proteins of bovine origin (Bos genus) and a large sequence coverage of a plant protein charybdin (Charybdis genus). The skull residue samples were dominated by benzoate and cinnamate derivatives and triterpenes consistent with a styrax-type resin (Styrax officinalis), thus providing the earliest known evidence of an odoriferous plant resin used in combination with an animal product.

Study of SEM preparation artefacts with correlative microscopy: Cell shrinkage of adherent cells by HMDS-drying.

Science.gov (United States)

Katsen-Globa, Alisa; Puetz, Norbert; Gepp, Michael M; Neubauer, Julia C; Zimmermann, Heiko

2016-11-01

One of the often reported artefacts during cell preparation to scanning electron microscopy (SEM) is the shrinkage of cellular objects, that mostly occurs at a certain time-dependent stage of cell drying. Various methods of drying for SEM, such as critical point drying, freeze-drying, as well as hexamethyldisilazane (HMDS)-drying, were usually used. The latter becomes popular since it is a low cost and fast method. However, the correlation of drying duration and real shrinkage of objects was not investigated yet. In this paper, cell shrinkage at each stage of preparation for SEM was studied. We introduce a shrinkage coefficient using correlative light microscopy (LM) and SEM of the same human mesenchymal stem cells (hMSCs). The influence of HMDS-drying duration on the cell shrinkage is shown: the longer drying duration, the more shrinkage is observed. Furthermore, it was demonstrated that cell shrinkage is inversely proportional to cultivation time: the longer cultivation time, the more cell spreading area and the less cell shrinkage. Our results can be applicable for an exact SEM quantification of cell size and determination of cell spreading area in engineering of artificial cellular environments using biomaterials. SCANNING 38:625-633, 2016. © 2016 Wiley Periodicals, Inc. © Wiley Periodicals, Inc.

The museum setup in the Benedictine dormitory of Monreale: the artworks of Santa Maria del Bosco and the textile artefacts of the Cathedral, Sicily, Italy

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Maria Concetta di Natale

2018-03-01

Full Text Available The recent decision to convert the Benedictine Dormitory in Monreale into an exhibition site offers the opportunity to enjoy the whole monumental complex where the wonderful cloister is the core attraction. It is on this site that the Norman Cathedral stands, brightly decorated with golden mosaics. The new exhibition has gathered together the artworks from the ruined abbey of Santa Maria del Bosco in Calatamauro and added them to the artefacts already exhibited at the Diocesan Museum. They include marble gravestones from the 16th-17th century church and those dating to the 18th century; one stone is in polychrome marble of the family of the canons, Candes and Donato; another was used for the burial of the monks from the period of the Olivetan refoundation, characterized by the Order’s coat of arms and attributed to Girolamo Musca. There are also majolica tiles from the chapels in cornu evangelij (left side of the altar adorned with large vegetal-shaped decorations, provided by Palermitan manufacturers in the mid-eighteenth century. They are found next to the remnants of the majolica tiles still in situ, executed in 1762 by the potters from Burgio, in Sicily. Rosario Rosso (also Russo and Giuseppe Virgadamo. Also commissioned after the refoundation of the holy temple are the four artworks by the painter Ippolito Ferrante, three of which, Sacrificio di Isacco, Melchisedec and Giale e Sisar, are on exhibition in the prestigious museum. Alongside these artworks are noteworthy textile artefacts made between the second half of the 16th and second half of the 18th centuries some of which are linked to the munificent figures of archbishops such as Ludovico II Torres and Francesco Testa.

Revision of the subfamily Euphorinae (excluding the tribe Meteorini Cresson) (Hymenoptera: Braconidae) from China

NARCIS (Netherlands)

Chen, X.; Achterberg, van C.

1997-01-01

The subfamily Euphorinae (excluding the tribe Meteorini Cresson) (Hymenoptera: Braconidae) from China is revised. In total 150 species, belonging to 24 genera, are treated and keyed. One genus (Heia gen. nov.; type species: Heia robustipes spec. nov.) and 69 species are described as new to science.

Constraining the supersaturation density equation of state from core-collapse supernova simulations? Excluded volume extension of the baryons

International Nuclear Information System (INIS)

Fischer, Tobias

2016-01-01

In this article the role of the supersaturation density equation of state (EOS) is explored in simulations of failed core-collapse supernova explosions. Therefore the nuclear EOS is extended via a one-parameter excluded-volume description for baryons, taking into account their finite and increasing volume with increasing density in excess of saturation density. Parameters are selected such that the resulting supernova EOS represent extreme cases, with high pressure variations at supersaturation density which feature extreme stiff and soft EOS variants of the reference case, i.e. without excluded-volume corrections. Unlike in the interior of neutron stars with central densities in excess of several times saturation density, central densities of core-collapse supernovae reach only slightly above saturation density. Hence, the impact of the supersaturation density EOS on the supernova dynamics as well as the neutrino signal is found to be negligible. It is mainly determined from the low- and intermediate-density domain, which is left unmodified within this generalized excluded volume approach. (orig.)

A new method of liquid crystal thermometry excluding human color sensation

International Nuclear Information System (INIS)

Kunugi, Tomoaki; Akino, Norio; Ueda, Masaharu.

1987-01-01

Some choresteric liquid crystals can be used as a thermometer because of their color changes with varying temperatures. However, it is impossible to employ human color sensation for precise quantitative evaluation of temperature from their color. Therefore, a new method of liquid crystal thermometry is developed using narrow band optical filters and an image processor to exclude the employment of human color sensation. Relations between filter wavelength and temperature were determined by calibration tests. Two dimensional temperature distributions on a heated plate were successfully measured by the present method. (author)

Method for excluding salt and other soluble materials from produced water

Science.gov (United States)

Phelps, Tommy J [Knoxville, TN; Tsouris, Costas [Oak Ridge, TN; Palumbo, Anthony V [Oak Ridge, TN; Riestenberg, David E [Knoxville, TN; McCallum, Scott D [Knoxville, TN

2009-08-04

A method for reducing the salinity, as well as the hydrocarbon concentration of produced water to levels sufficient to meet surface water discharge standards. Pressure vessel and coflow injection technology developed at the Oak Ridge National Laboratory is used to mix produced water and a gas hydrate forming fluid to form a solid or semi-solid gas hydrate mixture. Salts and solids are excluded from the water that becomes a part of the hydrate cage. A three-step process of dissociation of the hydrate results in purified water suitable for irrigation.

Feasibility of clinical magnetoencephalography (MEG) functional mapping in the presence of dental artefacts.

Science.gov (United States)

Hillebrand, A; Fazio, P; de Munck, J C; van Dijk, B W

2013-01-01

To evaluate the viability of MEG source reconstruction in the presence of large interference due to orthodontic material. We recorded the magnetic fields following a simple hand movement and following electrical stimulation of the median nerve (somatosensory evoked field -SEF). These two tasks were performed twice, once with and once without artificial dental artefacts. Temporal Signal Space Separation (tSSS) was applied to spatially filter the data and source reconstruction was performed according to standard procedures for pre-surgical mapping of eloquent cortex, applying dipole fitting to the SEF data and beamforming to the hand movement data. Comparing the data with braces to the data without braces, the observed distances between the activations following hand movement in the two conditions were on average 6.4 and 4.5 mm for the left and right hand, respectively, whereas the dipole localisation errors for the SEF were 4.1 and 5.4 mm, respectively. Without tSSS it was generally not possible to obtain reliable dipole fit or beamforming results when wearing braces. We confirm that tSSS is a required and effective pre-processing step for data recorded with the Elekta-MEG system. Moreover, we have shown that even the presence of large interference from orthodontic material does not significantly alter the results from dipole localisation or beamformer analysis, provided the data are spatially filtered by tSSS. State-of-the-art signal processing techniques enable the use of MEG for pre-surgical evaluation in a much larger clinical population than previously thought possible. Copyright © 2012 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Use of resting myocardial scintigraphy during chest pain to exclude diagnosis of acute myocardial infarction

International Nuclear Information System (INIS)

Barbirato, Gustavo Borges; Azevedo, Jader Cunha de; Felix, Renata Christian Martins; Correa, Patricia Lavatori; Volschan, Andre; Viegas, Monica; Pimenta, Lucia; Dohmann, Hans Fernando Rocha; Mesquita, Evandro Tinoco; Mesquita, Claudio Tinoco

2009-01-01

Background: Images of myocardial perfusion taken during an episode of chest pain have been used for patients in the emergency department. Objective: To evaluate the operating characteristics of 99m Tc-Tetrofosmin scintigraphy during an episode of chest pain to exclude the diagnosis of cute myocardial infarction. Methods: One hundred and eight patients admitted with chest pain, or up to four hours after the end of symptoms and non diagnostic electrocardiogram, underwent resting scintigraphy and measurement of troponin I concentrations. Patients with a history of myocardial infarction (MI) were not excluded (24 patients). Troponin I concentrations were determined at admission and 6 hours later. Nuclear physicians performed a blind analysis of the images, and myocardial infarction was confirmed whenever troponin I level increase was three times that of the control. Results: Resting perfusion image was abnormal in all 6 patients with MI. Only 1 patient had a normal image and increased troponin levels. Fifty-five patients had positive images without MI, and 46 patients had normal images and troponin levels. The prevalence of the disease was 6.5%. The sensitivity and specificity of the resting images during an episode of chest pain to diagnose MI was 85.7% and 45.5%, respectively. The negative predictive value was 97.7%. Conclusion: Patients undergoing chest pain protocol with SPECT showed an excellent negative predictive value to exclude diagnosis of myocardial infarction. These results suggest that resting perfusion image is an important tool at the chest pain unit. (author)

Diabetes mellitus and upper gut motility

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F. Mandolfino

2013-01-01

Full Text Available The aim of the study is to detect the presence of esophageal motor disorders in type I and II diabetic patients, and to establish whether there is any difference between patients with and without neuropathy. 118 diabetics patients (34 type I and 84 type II were investigated by water-perfused stationary esophageal manometry. Data were correlated with the presence of peripheral neurophaty. As a result 71% of patients affected by peripheral neuropathy showed manometric abnormalities against the 37% of the patients without neuropathy. Our experience has shown that patients with diabetes mellitus frequently present esophageal symptoms and manometric abnormalities. Manometric study of the esophagus has to be considered a useful investigative tool to manage and monitorize the gastrointestinal abnormalities in patients affected by diabetes mellitus.

75 FR 49528 - Freescale Semiconductor, Inc., Networking and Multimedia Group (“NMG”) Excluding the Multimedia...

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2010-08-13

... services for chips used in networking and multimedia products. The company reports that workers leased from... Multimedia Applications Division, including on-site workers of Synergy Services, Craftcorp, Directions..., Inc., Networking and Multimedia Group (``NMG'') Excluding the Multimedia Applications Division...

Correction of electrode modelling errors in multi-frequency EIT imaging.

Science.gov (United States)

Jehl, Markus; Holder, David

2016-06-01

The differentiation of haemorrhagic from ischaemic stroke using electrical impedance tomography (EIT) requires measurements at multiple frequencies, since the general lack of healthy measurements on the same patient excludes time-difference imaging methods. It has previously been shown that the inaccurate modelling of electrodes constitutes one of the largest sources of image artefacts in non-linear multi-frequency EIT applications. To address this issue, we augmented the conductivity Jacobian matrix with a Jacobian matrix with respect to electrode movement. Using this new algorithm, simulated ischaemic and haemorrhagic strokes in a realistic head model were reconstructed for varying degrees of electrode position errors. The simultaneous recovery of conductivity spectra and electrode positions removed most artefacts caused by inaccurately modelled electrodes. Reconstructions were stable for electrode position errors of up to 1.5 mm standard deviation along both surface dimensions. We conclude that this method can be used for electrode model correction in multi-frequency EIT.

A complementary set of electrochemical and X-ray synchrotron techniques to determine the passivation mechanism of iron treated in a new corrosion inhibitor solution specifically developed for the preservation of metallic artefacts

International Nuclear Information System (INIS)

Mirambet, F.; Reguer, S.; Rocca, E.; Hollner, S.; Testemale, D.

2010-01-01

Metallic artefacts of the cultural heritage are often stored in uncontrolled environmental conditions. They are very sensitive to atmospheric corrosion caused by a succession of wet and dry periods due to variations of relative humidity and temperature. To avoid the complete degradation of the metallic artefacts, new preventive strategies must be developed. In this context, we have studied new compounds based on sodium carboxylates solutions CH 3 (CH 2 ) n-2 COO - , Na + hereafter called NaC n . They allow the formation of a passive layer at the metallic surface composed of a metal-carboxylate complex. To understand the action of those inhibitors in the passivation process of iron we have performed electrochemical measurements and surface characterisation. Moreover, to monitor in real time the growth of the coating, in situ X-ray absorption spectroscopy (XAS) experiments at iron K-edge were carried out in an electrochemical cell. These analyses have shown that in the case of NaC 10 solution, the protection of iron surface is correlated to the precipitation of a well-organised layer of FeC 10 . These experiments confirmed that this compound is a fully oxidised trinuclear Fe(III) complex containing decanoate anions as ligands. Such information concerning the passive layer is a key factor to evaluate its stability and finally the long-term efficiency of the protection treatment. (orig.)

Accountability and the pressures to exclude: A cautionary tale from England.

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E. Rustique-Forrester

2005-04-01

Full Text Available Recent studies have produced conflicting findings about whether test-based rewards and sanctions create incentives that improve student performance, or hurdles that increase dropout and pushout rates from schools. This article reports the findings from a study that examined the impact of England's accountability reforms and investigated whether the confluent pressures associated with increased testing, school ranking systems, and other sanctions contributed to higher levels of student exclusion (expulsion and suspension. The study found that England's high-stakes approach to accountability, combined with the dynamics of school choice and other curriculum and testing pressures led to a narrowing of the curriculum, the marginalization of low-performing students, and a climate perceived by teachers to be less tolerant of students with academic and behavioral difficulties. A comparison of higher- and lower-excluding schools, however, found that these effects were more pronounced in the higher-excluding schools, which lacked strong systems and internal structures for supporting staff communication, teacher collaboration, and students' individual needs. The study offers an international perspective on recent trends toward greater accountability in education, pointing to a complex inter-relationship between the pressures of national policies and the unintended consequences on schools' organizational and teachers' instructional capacities. The study's findings raise particular implications for the United States and show that in the design of accountability systems, attention must be paid to how the pressures from accountability will affect the capacity of schools and teachers to respond to students who are low-performing and struggling academically.

Excluding Ethical Issues from U.S. History Textbooks: 911 and the War on Terror

Science.gov (United States)

Romanowski, Michael H.

2009-01-01

This research study examined nine secondary American history textbooks regarding their treatment of 9/11 and related events. The analysis centered on both the knowledge included and excluded from the discussion in each book. Particular attention was given to the moral and ethical issues relevant to 9/11. Findings show that textbooks vary in their…

21 CFR 1404.445 - What action may I take if a primary tier participant knowingly does business with an excluded or...

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2010-04-01

... 21 Food and Drugs 9 2010-04-01 2010-04-01 false What action may I take if a primary tier participant knowingly does business with an excluded or disqualified person? 1404.445 Section 1404.445 Food... § 1404.445 What action may I take if a primary tier participant knowingly does business with an excluded...

Reduction of the pace polarization artefact for capture detection applications by a tri-phasic stimulation pulse.

Science.gov (United States)

Sutton, R; Fröhlig, G; de Voogt, W G; Goethals, M; Hintringer, F; Kennergren, C; Scanu, P; Guilleman, D; Treese, N; Hartung, W M; Stammwitz, E; Muetstege, A

2004-11-01

This study investigated the ability to minimize pace polarization artefacts (PPA) by adjusting the post-stimulus pulse duration of a tri-phasic stimulation pulse. Adjustment of the stimulation pulse was enabled by downloading special study software into an already implanted pacemaker. Tests were performed in a total of 296 atrial leads and 311 ventricular leads. Both chronic and acute leads were included in the study. Statistically significant differences were found in the initial PPA (without any adjustment of the stimulus pulse) between atrial and ventricular leads. In addition, significant differences were observed among various lead models with respect to changes over time in the initial ventricular PPA. Successful PPA reduction was defined as a reduction of the PPA below 0.5 mV for atrial leads and below 1 mV for ventricular leads. Results show a success rate for ventricular and atrial PPA reduction of 97.8% and 98.7%, respectively. Threshold tests showed that after reduction of the PPA loss of ventricular capture can be reliably detected. However, atrial threshold tests showed many false positive evoked response detections. In addition, unexpectedly high evoked response amplitudes were observed in the atrium after reduction of the PPA. Results from additional measurements suggest that these high atrial evoked response amplitudes come from the influence of the input filter of the pacemaker.

A Multi-Channel Opto-Electronic Sensor to Accurately Monitor Heart Rate against Motion Artefact during Exercise

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Abdullah Alzahrani

2015-10-01

Full Text Available This study presents the use of a multi-channel opto-electronic sensor (OEPS to effectively monitor critical physiological parameters whilst preventing motion artefact as increasingly demanded by personal healthcare. The aim of this work was to study how to capture the heart rate (HR efficiently through a well-constructed OEPS and a 3-axis accelerometer with wireless communication. A protocol was designed to incorporate sitting, standing, walking, running and cycling. The datasets collected from these activities were processed to elaborate sport physiological effects. t-test, Bland-Altman Agreement (BAA, and correlation to evaluate the performance of the OEPS were used against Polar and Mio-Alpha HR monitors. No differences in the HR were found between OEPS, and either Polar or Mio-Alpha (both p > 0.05; a strong correlation was found between Polar and OEPS (r: 0.96, p < 0.001; the bias of BAA 0.85 bpm, the standard deviation (SD 9.20 bpm, and the limits of agreement (LOA from −17.18 bpm to +18.88 bpm. For the Mio-Alpha and OEPS, a strong correlation was found (r: 0.96, p < 0.001; the bias of BAA 1.63 bpm, SD 8.62 bpm, LOA from −15.27 bpm to +18.58 bpm. These results demonstrate the OEPS to be capable of carrying out real time and remote monitoring of heart rate.

Impact of metal artefacts due to EEG electrodes in brain PET/CT imaging

International Nuclear Information System (INIS)

Lemmens, Catherine; Nuyts, Johan; Dupont, Patrick; Montandon, Marie-Louise; Ratib, Osman; Zaidi, Habib

2008-01-01

The goal of this study is to investigate the impact of electroencephalogram (EEG) electrodes on the visual quality and quantification of 18 F-FDG PET images in neurological PET/CT examinations. For this purpose, the scans of 20 epilepsy patients with EEG monitoring were used. The CT data were reconstructed with filtered backprojection (FBP) and with a metal artefact reduction (MAR) algorithm. Both data sets were used for CT-based attenuation correction (AC) of the PET data. Also, a calculated AC (CALC) technique was considered. A volume of interest (VOI)-based analysis and a voxel-based quantitative analysis were performed to compare the different AC methods. Images were also evaluated visually by two observers. It was shown with simulations and phantom measurements that from the considered AC methods, the MAR-AC can be used as the reference in this setting. The visual assessment of PET images showed local hot spots outside the brain corresponding to the locations of the electrodes when using FBP-AC. In the brain, no abnormalities were observed. The quantitative analysis showed a very good correlation between PET-FBP-AC and PET-MAR-AC, with a statistically significant positive bias in the PET-FBP-AC images of about 5-7% in most brain voxels. There was also good correlation between PET-CALC-AC and PET-MAR-AC, but in the PET-CALC-AC images, regions with both a significant positive and negative bias were observed. EEG electrodes give rise to local hot spots outside the brain and a positive quantification bias in the brain. However, when diagnosis is made by mere visual assessment, the presence of EEG electrodes does not seem to alter the diagnosis. When quantification is performed, the bias becomes an issue especially when comparing brain images with and without EEG monitoring

Impact of metal artefacts due to EEG electrodes in brain PET/CT imaging

Energy Technology Data Exchange (ETDEWEB)

Lemmens, Catherine; Nuyts, Johan; Dupont, Patrick [Department of Nuclear Medicine and Medical Imaging Center, University Hospital Gasthuisberg and Katholieke Universiteit Leuven, Leuven (Belgium); Montandon, Marie-Louise; Ratib, Osman; Zaidi, Habib [Division of Nuclear Medicine, Geneva University Hospital, CH-1211 Geneva (Switzerland)], E-mail: catherine.lemmens@uz.kuleuven.be

2008-08-21

The goal of this study is to investigate the impact of electroencephalogram (EEG) electrodes on the visual quality and quantification of {sup 18}F-FDG PET images in neurological PET/CT examinations. For this purpose, the scans of 20 epilepsy patients with EEG monitoring were used. The CT data were reconstructed with filtered backprojection (FBP) and with a metal artefact reduction (MAR) algorithm. Both data sets were used for CT-based attenuation correction (AC) of the PET data. Also, a calculated AC (CALC) technique was considered. A volume of interest (VOI)-based analysis and a voxel-based quantitative analysis were performed to compare the different AC methods. Images were also evaluated visually by two observers. It was shown with simulations and phantom measurements that from the considered AC methods, the MAR-AC can be used as the reference in this setting. The visual assessment of PET images showed local hot spots outside the brain corresponding to the locations of the electrodes when using FBP-AC. In the brain, no abnormalities were observed. The quantitative analysis showed a very good correlation between PET-FBP-AC and PET-MAR-AC, with a statistically significant positive bias in the PET-FBP-AC images of about 5-7% in most brain voxels. There was also good correlation between PET-CALC-AC and PET-MAR-AC, but in the PET-CALC-AC images, regions with both a significant positive and negative bias were observed. EEG electrodes give rise to local hot spots outside the brain and a positive quantification bias in the brain. However, when diagnosis is made by mere visual assessment, the presence of EEG electrodes does not seem to alter the diagnosis. When quantification is performed, the bias becomes an issue especially when comparing brain images with and without EEG monitoring.

The Balloon-Based Manometry Evaluation of Swallowing in Patients with Amyotrophic Lateral Sclerosis

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Jerzy Tomik

2017-03-01

Full Text Available The aim of the study was to analyse the disturbances of the oro-pharyngeal swallowing phase of dysphagia in amyotrophic lateral sclerosis (ALS patients with the use of specific manometric measurements and to evaluate their plausible association with the duration of the disease. Seventeen patients with ALS were evaluated with manometric examinations of the oral and pharyngeal part of the gastrointestinal tract. Tests were carried out by using the oesophageal balloon-based method with four balloon transducers located 5 cm away from each other. The following manometric parameters were analysed: the base of tongue contraction (BTC and the upper oesophageal sphincter pressure (UESP, and the hypopharyngeal suction pump (HSP as well as the oro-pharyngeal, pharyngeal and hypopharyngeal transit time and average pharyngeal bolus velocity (oropharyngeal transit time (OTT, pharyngeal transit time (PTT, hypopharyngeal transit time (HTT and average pharyngeal bolus velocity (APBV, respectively. Manomatric examinations during swallowing in patients with ALS showed significant weakness of BTC, a decrease of HSP and a decrease of the velocity of bolus transit inside the pharynx which were particularly marked between the first and the third examination. Manometric examinations of the oro-pharyngeal part of the gastrointestinal tract are useful and supportive methods in the analysis of swallowing disturbances in ALS patients.

Rhizosphere characteristics of indigenously growing nickel hyperaccumulator and excluder plants on serpentine soil

International Nuclear Information System (INIS)

Wenzel, W.W.; Bunkowski, M.; Puschenreiter, M.; Horak, O.

2003-01-01

Field study reinforces that root exudates may contribute to nickel hyperaccumulation in Thlaspi goesingense Halacsy. - The role of rhizosphere processes in metal hyperaccumulation is largely unexplored and a matter of debate, related field data are virtually not available. We conducted a field survey of rhizosphere characteristics beneath the Ni hyperaccumulator Thlaspi goesingense Halacsy and the metal-excluder species Silene vulgaris L. and Rumex acetosella L. growing natively on the same serpentine site. Relative to bulk soil and to the rhizosphere of the excluder species, we found significantly increased DOC and Ni concentrations in water extracts of T. goesingense rhizosphere, whereas exchangeable Ni was depleted due to excessive uptake of Ni. Chemical speciation analysis using the MINTEQA2 software package revealed that enhanced Ni solubility in Thlaspi rhizosphere is driven by the formation of Ni-organic complexes. Moreover, ligand-induced dissolution of Ni-bearing minerals is likely to contribute to enhanced Ni solubility. Increased Mg and Ca concentrations and pH in Thlaspi rhizosphere are consistent with ligand-induced dissolution of orthosilicates such as forsterite (Mg 2 SiO 4 ). Our field data reinforce the hypothesis that exudation of organic ligands may contribute to enhanced solubility and replenishment of metals in the rhizosphere of hyperaccumulating species

Aspects concerning the lengths of the excluded shareholder’s liability towards third parties in the case of limited liability companies in Romania

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Andreea Stoican

2016-06-01

Full Text Available In the current context of reinventing the trading company law, at the end of a lengthy and extremely difficult economic crisis, when every participant in the economic life tried to find their own way to adapt and make their activity survive the new social and commercial realities, not few were the cases when some of the Shareholders were excluded and their liability was drawn onto the legal person itself. Nevertheless, there is a type of legal liability of the former Shareholders, excluded from the Company, that still is quite deficiently regulated and, despite the sound argumentation and comprehensive regulation of Law no. 31/1990, it fails to provide a clear and detailed explanation of the consequences, namely, of the consequences the exclusion of a Shareholder has over the Third Parties of good-faith that the legal person (the Company had or continues to have legal relations with. This paper thus aims at analysing one of the main effects of excluding Shareholders from the company, namely the extent of their liability towards the Third Parties, and it is structured in five parts, as follows: 1 Introduction, 2 About the Shareholders’ exclusion, 3 The effects of excluding a Shareholder from the Limited Liability Company, 4 The excluded Shareholder’s liability towards the Third Parties and 5 Conclusions.

A discrete fibre dispersion method for excluding fibres under compression in the modelling of fibrous tissues.

Science.gov (United States)

Li, Kewei; Ogden, Ray W; Holzapfel, Gerhard A

2018-01-01

Recently, micro-sphere-based methods derived from the angular integration approach have been used for excluding fibres under compression in the modelling of soft biological tissues. However, recent studies have revealed that many of the widely used numerical integration schemes over the unit sphere are inaccurate for large deformation problems even without excluding fibres under compression. Thus, in this study, we propose a discrete fibre dispersion model based on a systematic method for discretizing a unit hemisphere into a finite number of elementary areas, such as spherical triangles. Over each elementary area, we define a representative fibre direction and a discrete fibre density. Then, the strain energy of all the fibres distributed over each elementary area is approximated based on the deformation of the representative fibre direction weighted by the corresponding discrete fibre density. A summation of fibre contributions over all elementary areas then yields the resultant fibre strain energy. This treatment allows us to exclude fibres under compression in a discrete manner by evaluating the tension-compression status of the representative fibre directions only. We have implemented this model in a finite-element programme and illustrate it with three representative examples, including simple tension and simple shear of a unit cube, and non-homogeneous uniaxial extension of a rectangular strip. The results of all three examples are consistent and accurate compared with the previously developed continuous fibre dispersion model, and that is achieved with a substantial reduction of computational cost. © 2018 The Author(s).

Analysis of biomechanical parameters extracted from anorectal manometry of fecally-continent and incontinent patients Análisis de parámetros biomecánicos extraídos de la manometría recto-anal de pacientes con continencia e incontinencia fecal Análise de parâmetros biomecânicos extraídos da manometria anorretal de pacientes continentes e com incontinência fecal

Directory of Open Access Journals (Sweden)

Bianca Espindola

2012-12-01

Full Text Available OBJECTIVE: to evaluate the average resulting area from the Pressure x Time curves resulting from the manometric anorectal exam and compare it with the support capacity of voluntary squeeze. Materials and METHODS: the data set was represented by data from 11 exams from continent patients and eight exams from patients with grade III fecal incontinence. The manometric curves were delineated, and the areas and support capacity of voluntary squeeze calculated, by means of the R computer language and the algorithm developed. RESULTS: the resulting averages for support capacity of voluntary squeeze in continent patients and patients with grade III fecal incontinence were 33.07 seconds and 30.76 seconds (p>0.05 and the averages for area were 2362.04 mmHg x second and 947.92 mmHg x second (pOBJETIVO: evaluar el área media resultante proveniente de las curvas Presión versus Tiempo pertenecientes al examen manometría rectal y afrontarla con la capacidad de sustentación. Materiales y MÉTODOS: la casuística fue representada por datos de 11 exámenes de pacientes moderados y ocho exámenes de pacientes con incontinencia fecal grado III. Por medio del lenguaje computacional R y del algoritmo desarrollado fueron delineadas las curvas manométricas y calculadas las áreas y capacidades de sustentación. RESULTADOS: los medios resultantes de la capacidad de sustentación de pacientes moderados y con incontinencia fecal grado III fueron 33,07 segundos y 30,76 segundos (p>0,05 y las de la área, 2362,04 mmHg x según y 947,92 mmHg x según (pOBJETIVO: avaliar a área média resultante, proveniente das curvas pressão versus tempo, pertencentes ao exame manometria anorretal e confrontá-la com a capacidade de sustentação. MATERIAIS E MÉTODOS: a casuística foi representada por dados de 11 exames de pacientes continentes e oito exames de pacientes com incontinência fecal grau III. Por meio da linguagem computacional R e do algoritmo desenvolvido foram

Fully non-destructive elemental analyses of copper-alloy artefacts with neutron resonance capture between 1 eV and 10 keV

International Nuclear Information System (INIS)

Postma, H.; Blaauw, M.; Corvi, F.

2002-01-01

Neutron capture resonance analysis (NRCA) using a pulsed neutron beam and the time-of-flight (ToF) technique is a new method to determine the elemental compositions of artifacts. Neutron capture by an object can be observed by detecting the prompt capture gamma-radiation. Energies of resonance peaks in the ToF spectrum are the 'fingerprints' for elements. Since it is not necessary to determine the energy of the gamma-rays with any precision, it is possible to use a detector system with high detection efficiency. It is not necessary to take parts from an object for the analysis or to clean the surface or to do other things which might damage the object. Therefore NRCA is especially of interest for studying fragile, small or valuable objects from which one does not want to, or cannot take samples, or for which cleaning of even a small part of a surface is not desirable. Knowledge of the elemental composition of artifacts might be useful for archaeological or historical studies or to check the authenticity of an artifact. Recent experiments at the GELINA facility in Geel, Belgium show that indeed NRCA is a useful way to recognize elements on the basis of the energies of resonance in the ToF spectrum. We applied NRCA to several copper-alloy artifacts. In the studied objects very little activity was induced, which also disappeared quickly. Thus resonance energies allow us to recognize elements of an object. In addition, a quantitative analysis is possible on the basis of resonance areas. In the case of our artefacts the amounts of several elements (notably Sn, As, Zn, Fe, Sb, Ag, Au) were determined as ratios to copper. For a strong resonance it is necessary to take self-shielding into account. The effect of self-shielding made it possible to determine the absolute amount of copper by comparing the areas of a weak and a strong copper resonance, and thus also absolute amounts of the other components could be determined. The method of NRCA is discussed in relation to the

26 CFR 1.167(a)-14 - Treatment of certain intangible property excluded from section 197.

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2010-04-01

... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Treatment of certain intangible property... for Individuals and Corporations § 1.167(a)-14 Treatment of certain intangible property excluded from...) for rules relating to changes in method of accounting for property to which § 1.167(a)-14 applies...

Selective impairment of living things and musical instruments on a verbal 'Semantic Knowledge Questionnaire' in a case of apperceptive visual agnosia.

Science.gov (United States)

Masullo, Carlo; Piccininni, Chiara; Quaranta, Davide; Vita, Maria Gabriella; Gaudino, Simona; Gainotti, Guido

2012-10-01

Semantic memory was investigated in a patient (MR) affected by a severe apperceptive visual agnosia, due to an ischemic cerebral lesion, bilaterally affecting the infero-mesial parts of the temporo-occipital cortices. The study was made by means of a Semantic Knowledge Questionnaire (Laiacona, Barbarotto, Trivelli, & Capitani, 1993), which takes separately into account four categories of living beings (animals, fruits, vegetables and body parts) and of artefacts (furniture, tools, vehicles and musical instruments), does not require a visual analysis and allows to distinguish errors concerning super-ordinate categorization, perceptual features and functional/encyclopedic knowledge. When the total number of errors obtained on all the categories of living and non-living beings was considered, a non-significant trend toward a higher number of errors in living stimuli was observed. This difference, however, became significant when body parts and musical instruments were excluded from the analysis. Furthermore, the number of errors obtained on the musical instruments was similar to that obtained on the living categories of animals, fruits and vegetables and significantly higher of that obtained in the other artefact categories. This difference was still significant when familiarity, frequency of use and prototypicality of each stimulus entered into a logistic regression analysis. On the other hand, a separate analysis of errors obtained on questions exploring super-ordinate categorization, perceptual features and functional/encyclopedic attributes showed that the differences between living and non-living stimuli and between musical instruments and other artefact categories were mainly due to errors obtained on questions exploring perceptual features. All these data are at variance with the 'domains of knowledge' hypothesis', which assumes that the breakdown of different categories of living and non-living things respects the distinction between biological entities and

An eight-year prospective controlled study about the safety and diagnostic value of cardiac and non-cardiac 1.5-T MRI in patients with a conventional pacemaker or a conventional implantable cardioverter defibrillator.

Science.gov (United States)

Lupo, Pierpaolo; Cappato, Riccardo; Di Leo, Giovanni; Secchi, Francesco; Papini, Giacomo D E; Foresti, Sara; Ali, Hussam; De Ambroggi, Guido M G; Sorgente, Antonio; Epicoco, Gianluca; Cannaò, Paola M; Sardanelli, Francesco

2018-06-01

To investigate safety and diagnostic value of 1.5-T MRI in carriers of conventional pacemaker (cPM) or conventional implantable defibrillator (cICD). We prospectively compared cPM/cICD-carriers undergoing MRI (study group, SG), excluding those device-dependent or implanted cPM/cICD-carriers undergoing chest x-ray, CT or follow-up (reference group, RG). 142 MRI (55 cardiac) were performed in 120 patients with cPM (n=71) or cICD (n=71). In the RG 98 measurements were performed in 95 patients with cPM (n=40) or cICD (n=58). No adverse events were observed. No MRI prolonged/interrupted. All cPM/cICD were correctly reprogrammed after MRI without malfunctions. One temporary communication failure was observed in one cPM-carrier. Immediately after MRI, 12/14 device interrogation parameters did not change significantly (clinically negligible changes of battery voltage and cICD charging time), without significant variations for SG versus RG. Three-12 months after MRI, 9/11 device interrogation parameters did not change significantly (clinically negligible changes of battery impedance/voltage). Non-significant changes of three markers of myocardial necrosis. Non-cardiac MRI: 82/87 diagnostic without artefacts; 4/87 diagnostic with artefacts; 1/87 partially diagnostic. Cardiac MRI: in cPM-carriers, 14/15 diagnostic with artefacts, 1/15 partially diagnostic; in cICD-carriers, 9/40 diagnostic with artefacts, 22 partially diagnostic, nine non-diagnostic. A favourable risk-benefit ratio of 1.5-T MRI in cPM/cICD carriers was reported. • Cooperation between radiologists and cardiac electrophysiologists allowed safe 1.5-T MRI in cPM/cICD-carriers. • No adverse events for 142 MRI in 71 cPM-carriers and 71 cICD-carriers. • Ninety-nine per cent (86/87) of non-cardiac MRI in cPM/cICD-carriers were diagnostic. • All cPM-carrier cardiac MRIs had artefacts, 14 examinations diagnostic, 1 partially diagnostic. • Twenty-three per cent (9/40) of cardiac MRI in cICD-carriers were non-diagnostic.

North sea: a quarter of total's reserves (excluding the Middle East)

International Nuclear Information System (INIS)

Anon.

1995-01-01

In 1994, for the fifth successive year, Total increased its proven reserves of hydrocarbons which reach 4.3 Gboe (+ 6% compared to 1993). Outside the Middle East, the reserves show a development of 9% and reach the threshold of 2 Gboe. In 1994, Total's production of hydrocarbons reached 633,000 boe/d (+ 4%), despite a fall of 3% in oil production in the Middle East. Excluding the Middle East, production was increased to 345,000 boe/d (+ 12%), including 212,000 boe/d for gas (+ 20%). Exploration/production investments were 5.8 GF in 1994 (excluding labour) and the development program for reserves and production for the coming years is based on yearly investments of some 6 GF. Total's production in Europe, essentially in the North Sea, was 154,000 boe/d in 1994 (+ 12%). This zone has potential for significant growth for the group which has undertaken exploration surveys in the Western Shetlands and in Haltenbanken. In the British zone, the Dunbar field and its neighbour Ellon were brought into production in December 1994. In the Norwegian zone, the Froy field, was brought into production last June. In the Lille-Frigg field, whose production started in May, initial reserves are estimated at 6,7 Bcm of gas. Total Norge AS also has interests in the producing fields of Ekofisk, Frigg, East-Frigg, Heimdal, Sleipner East, Veslefrikk, Oseberg, Brage, in those of Sleipner West and Huldra (start-up scheduled for 1997) and in Troll (phase 1) which should be producing in 1996. In the Dutch zone, the K4b and K5a blocks brought into production last November hold reserves estimated at 20 Bcm; their production could reach 2 Bcm/year as from 1995. (authors). 1 tab., 1 photo

Fecoflowmetric Analysis of Anorectal Motor Function in Postoperative Anal-Preserving Surgery Patients With Low Rectal Cancer Comparison With the Wexner Score and Anorectal Manometry

Science.gov (United States)

Ryu, Yasuhiko; Akagi, Yoshito; Yagi, Minoru; Sasatomi, Teruo; Kinugasa, Tetsushi; Yamaguchi, Keizo; Oka, Yousuke; Fukahori, Suguru; Shiratsuchi, Ichitaro; Yoshida, Takefumi; Gotanda, Yukito; Tanaka, Natsuki; Ohchi, Takafumi; Romeo, Kansakar; Shirouzu, Kazuo

2015-01-01

The aim of this study was to elucidate whether fecoflowmetry (FFM) could evaluate more detailed evacuative function than anorectal manometry by comparing between FFM or anorectal manometric findings and the clinical questionnaires and the types of surgical procedure in the patients who received anal-preserving surgery. Fifty-three patients who underwent anal-preserving surgery for low rectal cancer were enrolled. The relationships between FFM or the manometric findings and the clinical questionnaires and the types of procedure of anal-preserving surgery were evaluated. There were significant differences between FFM markers and the clinical questionnaire and the types of the surgical procedure, whereas no significant relationship was observed between the manometric findings and the clinical questionnaire and the types of the surgical procedure. FFM might be feasible and useful for the objective assessment of evacuative function and may be superior to manometry for patients undergoing anal-preserving surgery. PMID:25594637

Effects of laparoscopic myotomy on the esophageal motility pattern of esophageal achalasia as measured by high-resolution manometry.

Science.gov (United States)

Salvador, Renato; Savarino, Edoardo; Pesenti, Elisa; Spadotto, Lorenzo; Voltarel, Guerrino; Capovilla, Giovanni; Cavallin, Francesco; Nicoletti, Loredana; Valmasoni, Michele; Ruol, Alberto; Merigliano, Stefano; Costantini, Mario

2017-09-01

Esophageal achalasia can be classified on the grounds of three distinct manometric patterns that correlate well with final outcome after laparoscopic Heller-Dor myotomy (LHM). No analytical data are available, however, on the postoperative picture and its possible correlation with final outcome. The aims of this study were: (a) to investigate whether manometric patterns change after LHM for achalasia; (b) to ascertain whether postoperative patterns and/or changes can predict final outcome; and (c) to test the hypothesis that the three known patterns represent different stages in the evolution of the disease. During the study period, we prospectively enlisted 206 consecutive achalasia patients who were assessed using high-resolution manometry (HRM) before undergoing LHM. Symptoms were scored using a detailed questionnaire. Barium swallow, endoscopy and HRM were performed, before and again 6 months after surgery. Preoperative HRM revealed the three known patterns with statistically different esophageal diameters (pattern I having the largest), and patients with pattern I had the highest symptom scores. The surgical treatment failed in 10 cases (4.9%). The only predictor of final outcome was the preoperative manometric pattern (p = 0.01). All patients with pattern I preoperatively had the same pattern afterward, whereas nearly 50% of patients with pattern III before LHM had patterns I or II after surgery. There were no cases showing the opposite trend. Neither a change of manometric pattern after surgery nor a patient's postoperative pattern was a predictor of final outcome, whereas preoperative pattern confirmed its prognostic significance. The three manometric patterns distinguishable in achalasia may represent different stages in the disease's evolution, pattern III and pattern I coinciding with the early and final stages of the disease, respectively.

Critical Approaches to Lifelong Education

Science.gov (United States)

Preston, Rosemary

1999-11-01

This paper argues that contemporary interest in lifelong learning can be seen as an artefact of the market. It points out how the attractive vocabulary associated with personal development and empowerment often masks other economic and social purposes. Bearing in mind the social function of education, the author compares the strategies for the promotion of lifelong learning designed for those in "included social categories" with the policies designed for those in marginal and excluded positions. It concludes by challenging its own position by citing positive learner experience in each case.

Clean Water Act (excluding Section 404). Environmental guidance program reference book: Revision 6

Energy Technology Data Exchange (ETDEWEB)

1993-01-15

This Reference Book contains a current copy of the Clean Water Act (excluding Section 404) and those regulations that implement the statutes and appear to be most relevant to US Department of Energy (DOE) activities. The document is provided to DOE and contractor staff for informational purposes only and should not be interpreted as legal guidance. Updates that include important new requirements will be provided periodically. Questions concerning this Reference Book may be directed to Mark Petts, EH-231 (202/586-2609).

Staroegyptské měděné a bronzové artefakty v Egyptském muzeu Lipské univerzity. Průběžná zpráva o projektu // Ancient Egyptian copper and bronze artefacts in the Egyptian Museum of Leipzig University. Preliminary report on the project

Directory of Open Access Journals (Sweden)

Martin Odler

2018-04-01

Full Text Available This article presents a preliminary report on the first results of the interdisciplinary project Early copper metallurgy in Ancient Egypt- a case study of the material from Agyptisches Museum - Georg Steindorff - der Universitat Leipzig, in cooperation of the Czech Institute of Egyptology, Faculty of Arts, Charles University in Prague, Institute of Chemistry and Technology in Prague and the Egyptian Museum in Leipzig. The project is focused on the analysis of a selected corpus of artefacts from ancient Egyptian and Nubian sites (fig. 1 . The analysed material was found in greatest part at the Egyptian sites of Abusir, Abydos and Giza and at the Nubian site of Aniba (fig. 2. The artefacts represent an outline of the development of ancient Egyptian metallurgy over more than one and half millennia, from the First Dynasty (ca 3100 - 2900 BC until almost the end of the New Kingdom (ca 1200 BC. The selected corpus of artefacts has been documented by X-ray radiography and computer tomography last year at the Institute of Mineralogy, Crystallography and Material Science of the Leipzig University. ln all, 86 artefacts were then sampled and a I most 100 samples obtained. The results of a metallography and SEMIEDS analysis of five selected artefacts, representing five different chronological stages of the corpus, are discussed in this article (Table 1 . The first one is a Dynasty 1 vessel from Abusir South (AMUL 2162; Fig. 3. This bowl was hammered out of copper sheet, with high contents of Ni, As and Fe. Non-metallic admixtures of copper sulfides are present in the inner structure, which is highly deformed by the hammering. The second is an Old Kingdom vessel from Giza made of arsenical copper, hammered and annealed (AMUL 2169; Figs. 4-5. The third is a lugged and decorated Middle Kingdom axe blade, hammered and annealed and made of copper with admixtures of As, Fe and S (AMUL 3952; Fig. 6. The fourth is a pair of tweezers from a C-Group tumulus N83 at

One negative polysomnogram does not exclude obstructive sleep apnea.

Science.gov (United States)

Meyer, T J; Eveloff, S E; Kline, L R; Millman, R P

1993-03-01

Night-to-night variability of apneas on overnight polymnography exists in patients with documented obstructive sleep apnea (OSA). In this study, we evaluated the possibility that this variability may be severe enough to miss the diagnosis of OSA in patients clinically at risk for the disease. We prospectively studied 11 patients who were deemed on clinical grounds to have probable OSA, but had a negative result on overnight polysomnography. Six of the 11 patients were found to have a positive second study with a significant rise in the apnea/hypopnea index (AHI) from 3.1 +/- 1.0 to 19.8 +/- 4.7 (mean +/- SEM, p cause of the negative first study in these patients is unclear, but it does not seem related to risk factor pattern, sleep architecture, or test interval. The change in AHI was not found to be rapid eye movement (REM)-dependent. This study demonstrates that a negative first-night study is insufficient to exclude OSA in patients with one or more clinical markers of the disease.

Linking probabilities of off-lattice self-avoiding polygons and the effects of excluded volume

International Nuclear Information System (INIS)

Hirayama, Naomi; Deguchi, Tetsuo; Tsurusaki, Kyoichi

2009-01-01

We evaluate numerically the probability of linking, i.e. the probability of a given pair of self-avoiding polygons (SAPs) being entangled and forming a nontrivial link type L. In the simulation we generate pairs of SAPs of N spherical segments of radius r d such that they have no overlaps among the segments and each of the SAPs has the trivial knot type. We evaluate the probability of a self-avoiding pair of SAPs forming a given link type L for various link types with fixed distance R between the centers of mass of the two SAPs. We define normalized distance r by r=R/R g,0 1 where R g,0 1 denotes the square root of the mean square radius of gyration of SAP of the trivial knot 0 1 . We introduce formulae expressing the linking probability as a function of normalized distance r, which gives good fitting curves with respect to χ 2 values. We also investigate the dependence of linking probabilities on the excluded-volume parameter r d and the number of segments, N. Quite interestingly, the graph of linking probability versus normalized distance r shows no N-dependence at a particular value of the excluded volume parameter, r d = 0.2

Assessment of potential soybean cadmium excluder cultivars at different concentrations of Cd in soils.

Science.gov (United States)

Zhi, Yang; He, Kangxin; Sun, Ting; Zhu, Yongqiang; Zhou, Qixing

2015-09-01

The selection of cadmium-excluding cultivars has been used to minimize the transfer of cadmium into the human food chain. In this experiment, five Chinese soybean plants were grown in three soils with different concentrations of Cd (0.15, 0.75 and 1.12mg/kg). Variations in uptake, enrichment, and translocation of Cd among these soybean cultivars were studied. The results indicated that the concentration of Cd in seeds that grew at 1.12mg/kg Cd in soils exceeded the permitted maximum levels in soybeans. Therefore, our results indicated that even some soybean cultivars grown on soils with permitted levels of Cd might accumulate higher concentrations of Cd in seeds that are hazardous to human health. The seeds of these five cultivars were further assessed for interactions between Cd and other mineral nutrient elements such as Ca, Cu, Fe, Mg, Mn and Zn. High Cd concentration in soil was found to inhibit the uptake of Mn. Furthermore, Fe and Zn accumulations were found to be enhanced in the seeds of all of the five soybean cultivars in response to high Cd concentration. Cultivar Tiefeng 31 was found to fit the criteria for a Cd-excluding cultivar under different concentrations of Cd in soils. Copyright © 2015. Published by Elsevier B.V.

Computer assisted strain-gauge plethysmography is a practical method of excluding deep venous thrombosis

International Nuclear Information System (INIS)

Goddard, A.J.P.; Chakraverty, S.; Wright, J.

2001-01-01

AIM: To evaluate a computed strain-gauge plethysmograph (CSGP) as a screening tool to exclude above knee deep venous thrombosis (DVT). METHODS: The first phase took place in the Radiology department. One hundred and forty-nine patients had both Doppler ultrasound and CSGP performed. Discordant results were resolved by venography where possible. The second phase took place in an acute medical admissions ward using a modified protocol. A further 173 patients had both studies performed. The results were collated and analysed. RESULTS: Phase 1. The predictive value of a negative CSGP study was 98%. There were two false-negative CSGP results (false-negative rate 5%), including one equivocal CSGP study which had deep venous thrombosis on ultrasound examination. Two patients thought to have thrombus on ultrasound proved not to have acute thrombus on venography. Phase 2. The negative predictive value of CSGP using a modified protocol was 97%. There were two definite and one possible false-negative studies (false-negative rate 4-7%). CONCLUSION: Computer strain-gauge plethysmograph can provide a simple, cheap and effective method of excluding lower limb DVT. However, its use should be rigorously assessed in each hospital in which it is used. Goddard, A.J.P., Chakraverty, S. and Wright, J. (2001)

Unexpected Complication with the New C3 Excluder: Cause and Treatment

International Nuclear Information System (INIS)

Katsargyris, Athanasios; Oikonomou, Kyriakos; Bracale, Umberto M.; Verhoeven, Eric L. G.

2013-01-01

The new C3 Gore Excluder delivery system enables both up/downward and rotational repositioning of the device before complete deployment. This contributes to more precise proximal landing and permits facilitation of the contralateral gate cannulation. During separate deployment, the position of the ipsilateral limb can also be readjusted. We have used the modified C3 delivery system in more than 50 patients, and in most cases, we were able to utilize the repositioning options of the device to achieve optimal fixation and sealing. However, we present a case where our attempt to readjust the position of the ipsilateral limb led to upward migration of the main body with coverage of the left renal artery origin. The latter was secured with a bare stent implantation.