The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Johannes N Keeman - One of the best experts on this subject based on the ideXlab platform.
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radiography in acute ankle injuries the ottawa ankle rules versus local diagnostic decision rules
Annals of Emergency Medicine, 2002Co-Authors: A C M Pijnenburg, Afina S Glas, Marnix A J De Roos, Kjell Bogaard, Jeroen G Lijmer, Patrick M Bossuyt, Rudolf M J M Butzelaar, Johannes N KeemanAbstract:Abstract Study Objective: We validate the Ottawa Ankle Rules and 2 Dutch ankle rules in distinguishing clinically significant fractures from insignificant fractures and other injuries in patients with a painful ankle presenting to the emergency department. Methods: This prospective comparison of 3 ankle rules was conducted in the ED of a 580-bed community teaching hospital in Amsterdam from January 1998 to April 1999. Participants included 647 consecutive patients aged 18 years or older presenting with a painful ankle after trauma. All physicians received extensive and pictorial training on how to correctly score the respective items of the rules. The physician on call recorded these items derived from history and physical examination on a standardized data Sheet. All patients subsequently underwent standard radiographic assessment. A radiologist and a trauma surgeon evaluated the radiographs blinded from the results of the data Sheet Form and the treatment given. The diagnostic perFormance of the 3 rules was measured in terms of sensitivity, specificity, and the reduction of radiographs. Receiver operating characteristic (ROC) curves were constructed, and the area under the ROC curves was calculated and compared. Results: Seventy-four fractures were seen, of which 41 were clinically significant. The Ottawa Ankle Rules had a sensitivity of 98% for identifying clinically significant fractures; the local rules scored 88% and 59%, respectively. The potential savings in radiographs for the 3 decision rules were 24%, 54%, and 82%, respectively. The area under the ROC curve was better for both the local rules (0.84 and 0.83) compared with the Ottawa Ankle Rules (0.76). Conclusion: Because the identification of all relevant fractures is more important than a reduction in radiographs, the higher sensitivity of the Ottawa Ankle Rules makes these most suitable for implementation in The Netherlands. [Pijnenburg ACM, Glas AS, de Roos MAJ, Bogaard K, Lijmer JG, Bossuyt PMM, Butzelaar RMJM, Keeman JN. Radiography in acute ankle injuries: the Ottawa Ankle Rules versus local diagnostic decision rules. Ann Emerg Med. June 2002;39:599-604.]
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radiography in acute ankle injuries the ottawa ankle rules versus local diagnostic decision rules
International Ankle symposium, 2002Co-Authors: A C M Pijnenburg, Afina S Glas, Marnix A J De Roos, Kjell Bogaard, Jeroen G Lijmer, Patrick M Bossuyt, Rudolf M J M Butzelaar, Johannes N KeemanAbstract:Study objective: We validate the Ottawa Ankle Rules and 2 Dutch ankle rules in distinguishing clinically significant fractures from insignificant fractures and other injuries in patients with a painful ankle presenting to the emergency department. Methods: This prospective comparison of 3 ankle rules was conducted in the ED of a 580-bed community teaching hospital in Amsterdam from January 1998 to April 1999. Participants included 647 consecutive patients aged 18 years or older presenting with a painful ankle after trauma. All physicians received extensive and pictorial training on how to correctly score the respective items of the rules. The physician on call recorded these items derived from history and physical examination on a standardized data Sheet All patients subsequently underwent standard radiographic assessment. A radiologist and a trauma surgeon evaluated the radiographs blinded from the results of the data Sheet Form and the treatment given. The diagnostic perFormance of the 3 rules was measured in terms of sensitivity, specificity, and the reduction of radiographs. Receiver operating characteristic (ROC) curves were constructed, and the area under the ROC curves was calculated and compared. Results: Seventy-four fractures were seen, of which 41 were clinically significant. The Ottawa Ankle Rules had a sensitivity of 98% for identifying clinically significant fractures; the local rules scored 88% and 59%, respectively. The potential savings in radiographs for the 3 decision rules were 24%, 54%, and 82%, respectively. The area under the ROC curve was better for both the local rules (0.84 and 0.83) compared with the Ottawa Ankle Rules (0.76). Conclusion: Because the identification of all relevant fractures is more important than a reduction in radiographs, the higher sensitivity of the Ottawa Ankle Rules makes these most suitable for implementation in The Netherlands.
A C M Pijnenburg - One of the best experts on this subject based on the ideXlab platform.
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radiography in acute ankle injuries the ottawa ankle rules versus local diagnostic decision rules
Annals of Emergency Medicine, 2002Co-Authors: A C M Pijnenburg, Afina S Glas, Marnix A J De Roos, Kjell Bogaard, Jeroen G Lijmer, Patrick M Bossuyt, Rudolf M J M Butzelaar, Johannes N KeemanAbstract:Abstract Study Objective: We validate the Ottawa Ankle Rules and 2 Dutch ankle rules in distinguishing clinically significant fractures from insignificant fractures and other injuries in patients with a painful ankle presenting to the emergency department. Methods: This prospective comparison of 3 ankle rules was conducted in the ED of a 580-bed community teaching hospital in Amsterdam from January 1998 to April 1999. Participants included 647 consecutive patients aged 18 years or older presenting with a painful ankle after trauma. All physicians received extensive and pictorial training on how to correctly score the respective items of the rules. The physician on call recorded these items derived from history and physical examination on a standardized data Sheet. All patients subsequently underwent standard radiographic assessment. A radiologist and a trauma surgeon evaluated the radiographs blinded from the results of the data Sheet Form and the treatment given. The diagnostic perFormance of the 3 rules was measured in terms of sensitivity, specificity, and the reduction of radiographs. Receiver operating characteristic (ROC) curves were constructed, and the area under the ROC curves was calculated and compared. Results: Seventy-four fractures were seen, of which 41 were clinically significant. The Ottawa Ankle Rules had a sensitivity of 98% for identifying clinically significant fractures; the local rules scored 88% and 59%, respectively. The potential savings in radiographs for the 3 decision rules were 24%, 54%, and 82%, respectively. The area under the ROC curve was better for both the local rules (0.84 and 0.83) compared with the Ottawa Ankle Rules (0.76). Conclusion: Because the identification of all relevant fractures is more important than a reduction in radiographs, the higher sensitivity of the Ottawa Ankle Rules makes these most suitable for implementation in The Netherlands. [Pijnenburg ACM, Glas AS, de Roos MAJ, Bogaard K, Lijmer JG, Bossuyt PMM, Butzelaar RMJM, Keeman JN. Radiography in acute ankle injuries: the Ottawa Ankle Rules versus local diagnostic decision rules. Ann Emerg Med. June 2002;39:599-604.]
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radiography in acute ankle injuries the ottawa ankle rules versus local diagnostic decision rules
International Ankle symposium, 2002Co-Authors: A C M Pijnenburg, Afina S Glas, Marnix A J De Roos, Kjell Bogaard, Jeroen G Lijmer, Patrick M Bossuyt, Rudolf M J M Butzelaar, Johannes N KeemanAbstract:Study objective: We validate the Ottawa Ankle Rules and 2 Dutch ankle rules in distinguishing clinically significant fractures from insignificant fractures and other injuries in patients with a painful ankle presenting to the emergency department. Methods: This prospective comparison of 3 ankle rules was conducted in the ED of a 580-bed community teaching hospital in Amsterdam from January 1998 to April 1999. Participants included 647 consecutive patients aged 18 years or older presenting with a painful ankle after trauma. All physicians received extensive and pictorial training on how to correctly score the respective items of the rules. The physician on call recorded these items derived from history and physical examination on a standardized data Sheet All patients subsequently underwent standard radiographic assessment. A radiologist and a trauma surgeon evaluated the radiographs blinded from the results of the data Sheet Form and the treatment given. The diagnostic perFormance of the 3 rules was measured in terms of sensitivity, specificity, and the reduction of radiographs. Receiver operating characteristic (ROC) curves were constructed, and the area under the ROC curves was calculated and compared. Results: Seventy-four fractures were seen, of which 41 were clinically significant. The Ottawa Ankle Rules had a sensitivity of 98% for identifying clinically significant fractures; the local rules scored 88% and 59%, respectively. The potential savings in radiographs for the 3 decision rules were 24%, 54%, and 82%, respectively. The area under the ROC curve was better for both the local rules (0.84 and 0.83) compared with the Ottawa Ankle Rules (0.76). Conclusion: Because the identification of all relevant fractures is more important than a reduction in radiographs, the higher sensitivity of the Ottawa Ankle Rules makes these most suitable for implementation in The Netherlands.
H Eskandari - One of the best experts on this subject based on the ideXlab platform.
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dynamic strain aging behavior of an ultra fine grained al mg alloy aa5052 processed via classical constrained groove pressing
Journal of materials research and technology, 2019Co-Authors: M Moradpour, F Khodabakhshi, H EskandariAbstract:Abstract In this study, severe plastic deFormation (SPD) was employed on an Al-Mg alloy (AA5052 series) in the annealed condition with Sheet Form geometry by using the classical constrained-groove pressing (CGP) process up to two passes at room temperature, and accordingly an equivalent plastic strain of ∼2.32 imposed into the Sheets. In relation to the microstructural features (cellular structure Formation and precipitates morphology), dynamic strain aging behavior of these processed Al-Mg alloys up to different passes were evaluated by elaborating the tensile property along rolling (RD) and transverse directions (TD) of Sheets in terms of anisotropy. Also, the effects of thermo-mechanical treatment in H34-temper condition on the characteristics of Al-Mg alloy was elaborated and compared with the SPD processing, as well. The results showed refinement of coarse grain structure (∼50 μm) for initial annealed alloy into the ultra-fine range (400–500 nm) after implementation of two CGP passes with significant homogenous enhancement of mechanical property. Hardness, yield, and tensile strengths were continuously improved up to ∼55%, 110%, and 20%, respectively, with a considerable deterioration of elongation (>90%). Notably, the strengthening mechanisms were elaborated by dislocation-based models to establish a microstructure–mechanical strength relationship.
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Dynamic strain aging behavior of an ultra-fine grained Al-Mg alloy (AA5052) processed via classical constrained groove pressing
Elsevier, 2019Co-Authors: M Moradpour, F Khodabakhshi, H EskandariAbstract:In this study, severe plastic deFormation (SPD) was employed on an Al-Mg alloy (AA5052 series) in the annealed condition with Sheet Form geometry by using the classical constrained-groove pressing (CGP) process up to two passes at room temperature, and accordingly an equivalent plastic strain of ∼2.32 imposed into the Sheets. In relation to the microstructural features (cellular structure Formation and precipitates morphology), dynamic strain aging behavior of these processed Al-Mg alloys up to different passes were evaluated by elaborating the tensile property along rolling (RD) and transverse directions (TD) of Sheets in terms of anisotropy. Also, the effects of thermo-mechanical treatment in H34-temper condition on the characteristics of Al-Mg alloy was elaborated and compared with the SPD processing, as well. The results showed refinement of coarse grain structure (∼50 μm) for initial annealed alloy into the ultra-fine range (400–500 nm) after implementation of two CGP passes with significant homogenous enhancement of mechanical property. Hardness, yield, and tensile strengths were continuously improved up to ∼55%, 110%, and 20%, respectively, with a considerable deterioration of elongation (>90%). Notably, the strengthening mechanisms were elaborated by dislocation-based models to establish a microstructure–mechanical strength relationship. Keywords: Severe plastic deFormation (SPD), Constrained groove pressing (CGP), Al-Mg alloy, Dynamic strain aging, Microstructure, Mechanical propert
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application of cgp cross route process for microstructure refinement and mechanical properties improvement in steel Sheets
Journal of Manufacturing Processes, 2013Co-Authors: F Khodabakhshi, H Eskandari, Masoud Abbaszadeh, S R MohebpourAbstract:Abstract A modified method of severe plastic deFormation (SPD) entitled constrained groove pressing-cross route (CGP-CR) was introduced for imposing a high magnitude of equivalent strain of about 2.32 per pass on the Sheet Form samples. The major benefit of this improved route compared to previous common route was the more homogeneity of strain in the rolling (RD) and transverse (TD) directions of Sheets. In this study, low carbon steel samples were used for examination of evolutions in microstructure and mechanical properties during SPD via CGP-CR process. Mechanical properties improvement were measured by tensile and macro hardness tests. The results indicate that CGP-CR process can effectively improve tensile strength; and also, yield stress and hardness of as-received low carbon steel samples were improved up to about 100% after two deFormation passes. Also, high magnitude of inhomogeneity can be observed in hardness distribution through first pass of the process which diminishes in the subsequent passes. Microstructural evolutions during process were monitored by optical microscopy observations and X-ray diffraction analysis. The results demonstrate that initial ferritic microstructure with grain size of about 30 μm was refined to a 225 nm cell structure after two passes of CGP-CR process.
Jonathan C Knowles - One of the best experts on this subject based on the ideXlab platform.
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evaluation of decellularization protocols for production of tubular small intestine submucosa scaffolds for use in oesophageal tissue engineering
Acta Biomaterialia, 2014Co-Authors: Omaer Syed, Jonathan C Knowles, Nick J Walters, Richard M Day, Haewon KimAbstract:Small intestine submucosa (SIS) has emerged as one of a number of naturally derived extracellular matrix (ECM) biomaterials currently in clinical use. In addition to clinical applications, ECM materials Form the basis for a variety of approaches within tissue engineering research. In our preliminary work it was found that SIS can be consistently and reliably made into tubular scaffolds which confer certain potential advantages. Given that decellularization protocols for SIS are applied to Sheet-Form SIS, it was hypothesized that a tubular-Form SIS would behave differently to pre-existing protocols. In this work, tubular SIS was produced and decellularized by the conventional peracetic acid-agitation method, peracetic acid under perfusion along with two commonly used detergent-perfusion protocols. The aim of this was to produce a tubular SIS that was both adequately decellularized and possessing the mechanical properties which would make it a suitable scaffold for oesophageal tissue engineering, which was one of the goals of this work. Analysis was carried out via mechanical tensile testing, DNA quantification, scanning electron and light microscopy, and a metabolic assay, which was used to give an indication of the biocompatibility of each decellularization method. Both peracetic acid protocols were shown to be unsuitable methods with the agitation-protocol-produced SIS, which was poorly decellularized, and the perfusion protocol resulted in poor mechanical properties. Both detergent-based protocols produced well-decellularized SIS, with no adverse mechanical effects; however, one protocol emerged, SDS/Triton X-100, which proved superior in both respects. However, this SIS showed reduced metabolic activity, and this cytotoxic effect was attributed to residual reagents. Consequently, the use of SIS produced using the detergent SD as the decellularization agent was deemed to be the most suitable, although the elimination of the DNase enzyme would give further improvement.
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degradation and drug release of phosphate glass polycaprolactone biological composites for hard tissue regeneration
Journal of Biomedical Materials Research Part B, 2005Co-Authors: Jonathan C KnowlesAbstract:Phosphate-based glass (P-glass) and poly(ϵ-caprolactone) (PCL) composites were fabricated in a Sheet Form by solvent extraction and thermal pressing methods, and the antibiotic drug Vancomycin was loaded within the composites for use as a hard-tissue regenerative. The degradation and drug-release rate of the composites in vitro were tailored by modifying the glass composition: 0.45P2O5-xCaO-(0.55-x)Na2O, where x = 0.2, 0.3, 0.4, and 0.5. Compared to pure PCL, all the P-glass/PCL composites degraded to a higher degree, and the composite with lower-CaO glass showed a higher material loss. This was attributed mainly to the dissolution of the glass component. The glass dissolution also increased the degradation of PCL component in the composites. The Vancomycin release from the composites was strongly dependent on the glass composition. Drug release in pure PCL was initially abrupt and flattened out over a prolonged period. However, glass/PCL composites (particularly in the glass containing higher-CaO) exhibited a reduced initial burst and a higher release rate later. Preliminary cell tests on the extracts from the glass/PCL composites showed favorable cell proliferation, but the level was dependent on the ionic concentration of the extracts. The cell proliferation on the diluted extracts from the composite with higher-CaO glass was significantly higher than that on the blank culture dish. These observations confirmed that the P-glass/PCL composites are potentially applicable for use as hard-tissue regeneration and wound-healing materials because of their controlled degradation and drug-release profile as well as enhanced cell viability. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
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degradation and drug release of phosphate glass polycaprolactone biological composites for hard tissue regeneration
Journal of Biomedical Materials Research, 2005Co-Authors: Jonathan C KnowlesAbstract:Phosphate-based glass (P-glass) and poly(∈-caprolactone) (PCL) composites were fabricated in a Sheet Form by solvent extraction and thermal pressing methods, and the antibiotic drug Vancomycin was loaded within the composites for use as a hard-tissue regenerative. The degradation and drug-release rate of the composites in vitro were tailored by modifying the glass composition: 0.45P 2 O 5 -xCaO-(0.55-x)Na 2 O, where x = 0.2,0.3,0.4, and 0.5. Compared to pure PCL, all the P-glass/PCL composites degraded to a higher degree, and the composite with lower-CaO glass showed a higher material loss. This was attributed mainly to the dissolution of the glass component. The glass dissolution also increased the degradation of PCL component in the composites. The Vancomycin release from the composites was strongly dependent on the glass composition. Drug release in pure PCL was initially abrupt and flattened out over a prolonged period. However, glass/PCL composites (particularly in the glass containing higher-CaO) exhibited a reduced initial burst and a higher release rate later. Preliminary cell tests on the extracts from the glass/PCL composites showed favorable cell proliferation, but the level was dependent on the ionic concentration of the extracts. The cell proliferation on the diluted extracts from the composite with higher-CaO glass was significantly higher than that on the blank culture dish. These observations confirmed that the P-glass/PCL composites are potentially applicable for use as hard-tissue regeneration and wound-healing materials because of their controlled degradation and drug-release profile as well as enhanced cell viability.
Patrick M Bossuyt - One of the best experts on this subject based on the ideXlab platform.
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radiography in acute ankle injuries the ottawa ankle rules versus local diagnostic decision rules
Annals of Emergency Medicine, 2002Co-Authors: A C M Pijnenburg, Afina S Glas, Marnix A J De Roos, Kjell Bogaard, Jeroen G Lijmer, Patrick M Bossuyt, Rudolf M J M Butzelaar, Johannes N KeemanAbstract:Abstract Study Objective: We validate the Ottawa Ankle Rules and 2 Dutch ankle rules in distinguishing clinically significant fractures from insignificant fractures and other injuries in patients with a painful ankle presenting to the emergency department. Methods: This prospective comparison of 3 ankle rules was conducted in the ED of a 580-bed community teaching hospital in Amsterdam from January 1998 to April 1999. Participants included 647 consecutive patients aged 18 years or older presenting with a painful ankle after trauma. All physicians received extensive and pictorial training on how to correctly score the respective items of the rules. The physician on call recorded these items derived from history and physical examination on a standardized data Sheet. All patients subsequently underwent standard radiographic assessment. A radiologist and a trauma surgeon evaluated the radiographs blinded from the results of the data Sheet Form and the treatment given. The diagnostic perFormance of the 3 rules was measured in terms of sensitivity, specificity, and the reduction of radiographs. Receiver operating characteristic (ROC) curves were constructed, and the area under the ROC curves was calculated and compared. Results: Seventy-four fractures were seen, of which 41 were clinically significant. The Ottawa Ankle Rules had a sensitivity of 98% for identifying clinically significant fractures; the local rules scored 88% and 59%, respectively. The potential savings in radiographs for the 3 decision rules were 24%, 54%, and 82%, respectively. The area under the ROC curve was better for both the local rules (0.84 and 0.83) compared with the Ottawa Ankle Rules (0.76). Conclusion: Because the identification of all relevant fractures is more important than a reduction in radiographs, the higher sensitivity of the Ottawa Ankle Rules makes these most suitable for implementation in The Netherlands. [Pijnenburg ACM, Glas AS, de Roos MAJ, Bogaard K, Lijmer JG, Bossuyt PMM, Butzelaar RMJM, Keeman JN. Radiography in acute ankle injuries: the Ottawa Ankle Rules versus local diagnostic decision rules. Ann Emerg Med. June 2002;39:599-604.]
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radiography in acute ankle injuries the ottawa ankle rules versus local diagnostic decision rules
International Ankle symposium, 2002Co-Authors: A C M Pijnenburg, Afina S Glas, Marnix A J De Roos, Kjell Bogaard, Jeroen G Lijmer, Patrick M Bossuyt, Rudolf M J M Butzelaar, Johannes N KeemanAbstract:Study objective: We validate the Ottawa Ankle Rules and 2 Dutch ankle rules in distinguishing clinically significant fractures from insignificant fractures and other injuries in patients with a painful ankle presenting to the emergency department. Methods: This prospective comparison of 3 ankle rules was conducted in the ED of a 580-bed community teaching hospital in Amsterdam from January 1998 to April 1999. Participants included 647 consecutive patients aged 18 years or older presenting with a painful ankle after trauma. All physicians received extensive and pictorial training on how to correctly score the respective items of the rules. The physician on call recorded these items derived from history and physical examination on a standardized data Sheet All patients subsequently underwent standard radiographic assessment. A radiologist and a trauma surgeon evaluated the radiographs blinded from the results of the data Sheet Form and the treatment given. The diagnostic perFormance of the 3 rules was measured in terms of sensitivity, specificity, and the reduction of radiographs. Receiver operating characteristic (ROC) curves were constructed, and the area under the ROC curves was calculated and compared. Results: Seventy-four fractures were seen, of which 41 were clinically significant. The Ottawa Ankle Rules had a sensitivity of 98% for identifying clinically significant fractures; the local rules scored 88% and 59%, respectively. The potential savings in radiographs for the 3 decision rules were 24%, 54%, and 82%, respectively. The area under the ROC curve was better for both the local rules (0.84 and 0.83) compared with the Ottawa Ankle Rules (0.76). Conclusion: Because the identification of all relevant fractures is more important than a reduction in radiographs, the higher sensitivity of the Ottawa Ankle Rules makes these most suitable for implementation in The Netherlands.
