497 research outputs found

    Ultrasonic metal sheet thickness measurement without prior wave speed calibration

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    Conventional ultrasonic mensuration of sample thickness from one side only requires the bulk wave reverberation time and a calibration speed. This speed changes with temperature, stress, and microstructure, limiting thickness measurement accuracy. Often, only one side of a sample is accessible, making in situ calibration impossible. Non-contact ultrasound can generate multiple shear horizontal guided wave modes on one side of a metal plate. Measuring propagation times of each mode at different transducer separations, allows sheet thickness to be calculated to better than 1% accuracy for sheets of at least 1.5 mm thickness, without any calibration

    Use of positron emission tomography in evaluation of brachial plexopathy in breast cancer patients

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    18-Fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) has previously been used successfully to image primary and metastatic breast cancer. In this pilot study, 19 breast cancer patients with symptoms/signs referrable to the brachial plexus were evaluated with 18FDG-PET. In 11 cases computerized tomography (CT) scanning was also performed. Of the 19 patients referred for PET study, 14 had abnormal uptake of 18FDG in the region of the symptomatic plexus. Four patients had normal PET studies and one had increased FDG uptake in the chest wall that accounted for her axillary pain. CT scans were performed in 9 of the 14 patients who had positive brachial plexus PET studies; six of these were either normal or showed no clear evidence of recurrent disease, while three CTs demonstrated clear brachial plexus involvement. Of two of the four patients with normal PET studies, one has had complete resolution of symptoms untreated while the other was found to have cervical disc herniation on magnetic resonance imaging (MRI) scan. The remaining two patients almost certainly had radiation-induced plexopathy and had normal CT, MRI and PET study. These data suggest that 18FDG-PET scanning is a useful tool in evaluation of patients with suspected metastatic plexopathy, particularly if other imaging studies are normal. It may also be useful in distinguishing between radiation-induced and metastatic plexopathy. © 1999 Cancer Research Campaig

    Recovering from destruction: the conservation, reintegration and perceptual analysis of a flood-damaged painting by John Martin

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    This paper describes treatment issues surrounding John Martin’s epic Destruction of Pompeii and Herculaneum (1821). The painting experienced such extensive structural damage following the 1928 Thames flood that it was considered destroyed. Despite major water damage affecting all layers of the painting and the loss of approximately one-fifth of the canvas, recent examination revealed the work to be in restorable condition. However, the extreme nature of the damages necessitates special ethical and technical considerations with regard to treatment, especially for the reintegration of the large missing portion. A consideration of viewer perception of the digitally simulated options for reintegration and their influence on viewer gaze behaviour, monitored via novel eye-tracking methods, was used to inform the treatment process

    Designing evaluation for a high school research integrated learning outreach program

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    BACKGROUND Educational outreach programs that bridge university and high school contexts aim to increase students’ engagement and commitment to STEM career pathways (Tytler et al., 2017). Likewise, opportunities for students to engage in authentic scientific research (research integrated learning, RIL) have also been demonstrated to develop STEM skills and lead to increased STEM identity and aspiration (Beier et al., 2018; Stets et al., 2017). Outreach programs may also support access to STEM pathways for students from diverse backgrounds (Scull & Cuthill, 2010). However, these positive outcomes cannot be assumed from program design alone. Rigorous evaluation is required to ensure that goals are being reached and to support iterative improvements in program design (Australian Academy of Science, 2019). AIMS This study presents the design and preliminary results of an evaluation of a high school outreach program, SciX (this intervention is described in another ACSME 2023 abstract by Laura McKemmish). The evaluation approach focuses on the program’s impact on students’ perceived scientific skills, science identity, and commitment to pursue a career in STEM. It also explores differences in these effects between demographic groups (girls, students from rural locations, students from low SES schools). Other program goals including sustainability, scalability, and a positive impact on teachers and mentors are also incorporated. The goal of this research is to support iterative improvement of the intervention and identify transferrable principles to enhance the effectiveness and equity of similar student research programs. DESIGN AND METHODS An evaluation framework was designed around a program logic model that also incorporated elements of motivation theory and identity theory. Student surveys (University of New South Wales Human Research Ethics approved) were administered immediately before and immediately following the one-week RIL summer school in 2021-2023. A total of 238 students completed a survey following the intervention. RESULTS AND CONCLUSIONS The full evaluation framework will involve mixed methods studies that incorporate survey and interview data from students, teachers, and mentors, as well as key informant interviews and program administration data. Preliminary results will be presented from student surveys. These results show positive experiences (73% of respondents were extremely happy they attended) and significant increases in science identity, which were greater for girls. Survey results also reveal the key importance of the student-mentor relationship to the experience, which will be further explored in later studies. Initial results have informed program design and future iterations of the evaluation research. REFERENCES Australian Academy of Science. (2019). Women in STEM Decadal Plan. www.science.org.au/womeninSTEMplan Beier, M. E., Kim, M. H., Saterbak, A., Leautaud, V., Bishnoi, S., & Gilberto, J. M. (2018). The effect of authentic project‐based learning on attitudes and career aspirations in STEM. Journal of Research in Science Teaching, 56(1), 3-23. Scull, S., & Cuthill, M. (2010). Engaged outreach: using community engagement to facilitate access to higher education for people from low socio‐economic backgrounds. Higher Education Research & Development, 29(1), 59-74. Stets, J. E., Brenner, P. S., Burke, P. J., & Serpe, R. T. (2017). The science identity and entering a science occupation. Social science research, 64, 1-14. Tytler, R., Symington, D., & Cripps Clark, J. (2017). Community-School Collaborations in Science: Towards Improved Outcomes Through Better Understanding of Boundary Issues. International Journal of Science and Mathematics Education, 15(4), 643-661

    FDG–PET in the prediction of survival of patients with cancer of the pancreas: a pilot study

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    Carcinoma of the pancreas is an aggressive tumour with an extremely poor prognosis. Recent studies have shown that chemotherapy can improve survival as well as quality of life. Since the prognosis is generally poor, the identification of early responders to chemotherapy is important to avoid unnecessary toxicity in patients who are not responding. Response assessment by conventional radiographic methods is problematical because treatment induces fibrosis and makes tumour measurements difficult. The aim of this pilot study was to assess 18-fluoro-deoxy-glucose positron emission tomography (FDG-PET) as an early marker of the benefit of chemotherapy. Eleven patients with histologically proven adenocarcinoma of the pancreas were treated with protracted venous infusional 5-fluorouracil (PVI 5-FU) alone or PVI 5-FU and mitomycin C (MMC). FDG-PET scans were performed prior to and at 1 month following the commencement of chemotherapy. FDG uptake was compared with the tumour dimensions measured on a computer tomographic (CT) scan. Patients were followed up for relapse, death and symptomatic response. Three of the 11 patients had no measurable FDG uptake prior to chemotherapy. Of the eight patients who had measurable uptake prior to treatment, seven had a reduction in uptake at 1 month. Six out of the 11 patients had no measurable FDG uptake at 1 month. The overall survival (OS) in these patients ranged from 124 to 1460 days, with a median of 318.5 days. This was superior in comparison to patients who had residual FDG uptake at 1 month (median survival 318.5 days vs 139 days;P = 0.034) and there was a trend to improved symptoms (84% [5/6] vs 20% [1/5];P = 0.13). There was no statistically significant correlation between best CT response and FDG uptake at 1 month. These results suggest that the absence of FDG uptake at 1 month following chemotherapy for carcinoma of the pancreas is an indicator of improved overall survival. This suggests that FDG-PET may be superior to response assessment by conventional radiographic methods and FDG-PET may have the potential to help make difficult treatment decisions in the management of pancreatic cancer. Larger prospective studies are required to confirm this finding. © 2000 Cancer Research Campaig

    Understanding feedback report uptake: process evaluation findings from a 13-month feedback intervention in long-term care settings

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    Abstract Background Long-term care settings provide care to a large proportion of predominantly older, highly disabled adults across the United States and Canada. Managing and improving quality of care is challenging, in part because staffing is highly dependent on relatively non-professional health care aides and resources are limited. Feedback interventions in these settings are relatively rare, and there has been little published information about the process of feedback intervention. Our objectives were to describe the key components of uptake of the feedback reports, as well as other indicators of participant response to the intervention. Methods We conducted this project in nine long-term care units in four facilities in Edmonton, Canada. We used mixed methods, including observations during a 13-month feedback report intervention with nine post-feedback survey cycles, to conduct a process evaluation of a feedback report intervention in these units. We included all facility-based direct care providers (staff) in the feedback report distribution and survey administration. We conducted descriptive analyses of the data from observations and surveys, presenting this in tabular and graphic form. We constructed a short scale to measure uptake of the feedback reports. Our analysis evaluated feedback report uptake by provider type over the 13 months of the intervention. Results We received a total of 1,080 survey responses over the period of the intervention, which varied by type of provider, facility, and survey month. Total number of reports distributed ranged from 103 in cycle 12 to 229 in cycle 3, although the method of delivery varied widely across the period, from 12% to 65% delivered directly to individuals and 15% to 84% left for later distribution. The key elements of feedback uptake, including receiving, reading, understanding, discussing, and reporting a perception that the reports were useful, varied by survey cycle and provider type, as well as by facility. Uptake, as we measured it, was consistently high overall, but varied widely by provider type and time period. Conclusions We report detailed process data describing the aspects of uptake of a feedback report during an intensive, longitudinal feedback intervention in long-term care facilities. Uptake is a complex process for which we used multiple measures. We demonstrate the feasibility of conducting a complex longitudinal feedback intervention in relatively resource-poor long-term care facilities to a wider range of provider types than have been included in prior feedback interventions.http://deepblue.lib.umich.edu/bitstream/2027.42/110519/1/13012_2015_Article_208.pd

    First shark from the late Devonian (Frasnian) gogo formation, Western Australia sheds new light on the development of tessellated calcified cartilage

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    Background: Living gnathostomes (jawed vertebrates) comprise two divisions, Chondrichthyes (cartilaginous fishes, including euchondrichthyans with prismatic calcified cartilage, and extinct stem chondrichthyans) and Osteichthyes (bony fishes including tetrapods). Most of the early chondrichthyan (‘shark’) record is based upon isolated teeth, spines, and scales, with the oldest articulated sharks that exhibit major diagnostic characters of the group—prismatic calcified cartilage and pelvic claspers in males—being from the latest Devonian, c. 360 Mya. This paucity of information about early chondrichthyan anatomy is mainly due to their lack of endoskeletal bone and consequent low preservation potential. Methodology/Principal Findings: Here we present new data from the first well-preserved chondrichthyan fossil from the early Late Devonian (ca. 380–384 Mya) Gogo Formation Lägerstatte of Western Australia. The specimen is the first Devonian shark body fossil to be acid-prepared, revealing the endoskeletal elements as three-dimensional undistorted units: Meckel’s cartilages, nasal, ceratohyal, basibranchial and possible epibranchial cartilages, plus left and right scapulocoracoids, as well as teeth and scales. This unique specimen is assigned to Gogoselachus lynnbeazleyae n. gen. n. sp.Conclusions/Significance: The Meckel’s cartilages show a jaw articulation surface dominated by an expansive cotylus, and a small mandibular knob, an unusual condition for chondrichthyans. The scapulocoracoid of the new specimen shows evidence of two pectoral fin basal articulation facets, differing from the standard condition for early gnathostomes which have either one or three articulations. The tooth structure is intermediate between the ‘primitive’ ctenacanthiform and symmoriiform condition, and more derived forms with a euselachian-type base. Of special interest is the highly distinctive type of calcified cartilage forming the endoskeleton, comprising multiple layers of nonprismatic subpolygonal tesserae separated by a cellular matrix, interpreted as a transitional step toward the tessellated prismatic calcified cartilage that is recognized as the main diagnostic character of the chondrichthyans

    A symmoriiform chondrichthyan braincase and the origin of chimaeroid fishes

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    Chimaeroid fishes (Holocephali) are one of the four principal divisions of modern gnathostomes (jawed vertebrates). Despite only 47 described living species1, chimaeroids are the focus of resurgent interest as potential archives of genomic data2 and for the unique perspective they provide on chondrichthyan and gnathostome ancestral conditions. Chimaeroids are also noteworthy for their highly derived body plan1,3,4. However, like other living groups with distinctive anatomies5, fossils have been of limited use in unravelling their evolutionary origin, as the earliest recognized examples already exhibit many of the specializations present in modern forms6,7. Here we report the results of a computed tomography analysis of Dwykaselachus, an enigmatic chondrichthyan braincase from the ~280 million year old Karoo sediments of South Africa8. Externally, the braincase is that of a symmoriid shark9,10,11,12,13and is by far the most complete uncrushed example yet discovered. Internally, the morphology exhibits otherwise characteristically chimaeroid specializations, including the otic labyrinth arrangement and the brain space configuration relative to exceptionally large orbits. These results have important implications for our view of modern chondrichthyan origins, add robust structure to the phylogeny of early crown group gnathostomes, reveal preconditions that suggest an initial morpho-functional basis for the derived chimaeroid cranium, and shed new light on the chondrichthyan response to the extinction at the end of the Devonian period
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