240 research outputs found
Volume Averaged Modeling of the Oxidation of Porous Carbon Fiber Material
Charring ablators remain the premium choice for space exploration missions that involve atmospheric re-entry. This type of ablative material is composed of a carbon matrix, usually made of fibers, which is then impregnated with a resin. During re-entry, the high heat flux produced by convective heating causes the material to chemically react. First, the resin pyrolyzes, and is vaporized into a gas that travels through the material, and is eventually ejected at the surface. Then, as the temperature rises, the surface of the porous matrix recess through ablative processes. For re-entry conditions typical of space exploration missions, this is mainly diffusion limited oxidation. However, recent studies have shown that oxygen from the atmosphere actually penetrates a thin layer of the porous material, oxidizing the carbon fibers from within.
This research activity presents a volume-averaged fiber-scale oxidation model, based on the one previously developed by Lachaud et al. The present model, however, solves the momentum equation as well as the energy equation. Results based on a an experimental test case are presented. The importance of solving both equations is clearly demonstrated, and a new value for carbon fiber oxidation reactivity is suggested
Phase 2 study of intralesional PV-10 in refractory metastatic melanoma
Purpose. This international, multicenter, single-arm trial assessed efficacy and safety of intralesional rose bengal (PV-10) in 80 patients with refractory cutaneous or subcutaneous metastatic melanoma. Methods. Sixty-two stage III and 18 stage IV melanoma patients with disease refractory to a median of six prior interventions received intralesional PV-10 into up to 20 cutaneous and subcutaneous lesions up to four times over a 16-week period and were followed for 52 weeks. Objectives were to determine best overall response rate in injected target lesions and uninjected bystander lesions, assess durability of response, and characterize adverse events. Results. For target lesions, the best overall response rate was 51%, and the complete response rate was 26%. Median time to response was 1.9 months, and median duration of response was 4.0 months, with 8% of patients having no evidence of disease after 52 weeks. Response was dependent on untreated disease burden, with complete response achieved in 50% of patients receiving PV-10 to all of their disease. Response of target lesions correlated with bystander lesion regression and the occurrence of locoregional blistering. Adverse events were predominantly mild to moderate and locoregional to the treatment site, with no treatment-associated grade 4 or 5 adverse events. Conclusions. Intralesional PV-10 yielded durable local control with high rates of complete response. Toxicity was confined predominantly to the injection site. Cutaneous bystander tumor regression is consistent with an immunologic response secondary to ablation. This intralesional approach for local disease control could be complementary to current and investigational treatments for melanoma.John F. Thompson, Sanjiv S. Agarwala, B. Mark Smithers, Merrick I. Ross, Charles R. Scoggins, Brendon J. Coventry, Susan J. Neuhaus, David R. Minor, Jamie M. Singer, and Eric A. Wachte
Discipline-Specific Compared to Generic Training of Teachers in Higher Education
A recurrent theme arising in the higher education sector is the suitability and effectiveness of generic versus discipline-specific training of university teachers, who are often recruited based on their disciplinary specialties to become teachers in higher education. We compared two groups of participants who had undergone training using a generic post-graduate certificate in higher education (PGCertGeneric) versus a discipline-specific course in veterinary education (PGCertVetEd). The study was conducted using a survey that allowed comparison of participants who completed PGCertGeneric (n=21) with PGCertVetEd (n=22). Results indicated that participants from both PGCertGeneric and PGCertVetEd considered teaching to be satisfying and important to their careers, valued the teaching observation component of the course, and identified similar training needs. However, the participants of the PGCertVetEd felt that the course made them better teachers, valued the relevance of the components taught, understood course design better, were encouraged to do further courses/reading in teaching and learning, changed their teaching as a result of the course, and were less stressed about teaching as compared to the PGCertGeneric participants (p<.05). It is likely that the PGCertVetEd, which was designed and developed by veterinarians with a wider understanding of the veterinary sector, helped the participants perceive the training course as suited to their needs
Coal-Tar-Based Pavement Sealcoat and PAHs: Implications for the Environment, Human Health, and Stormwater Management
Perception Is Reality: quality metrics in pancreas surgery – a Central Pancreas Consortium (CPC) analysis of 1399 patients
Several groups have defined pancreatic surgery quality metrics that identify centers delivering quality care. Although these metrics are perceived to be associated with good outcomes, their relationship with actual outcomes has not been established
Community-powered urban stream restoration: A vision for sustainable and resilient urban ecosystems
Urban streams can provide amenities to people living in cities, but those benefits are reduced when streams become degraded, potentially even causing harm (disease, toxic compounds, etc.). Governments and institutions invest resources to improve the values and services provided by urban streams; however, the conception, development, and implementation of such projects may not include meaningful involvement of community members and other stakeholders. Consequently, project objectives may be misaligned with community desires and needs, and projects may fail to achieve their goals. In February 2020, the 5(th) Symposium on Urbanization and Stream Ecology, an interdisciplinary meeting held every 3 to 5 y, met in Austin, Texas, USA, to explore new approaches to urban stream projects, including ways to maximize the full range of potential benefits by better integrating community members into project identification and decision making. The symposium included in-depth discussion about 4 nearby field case studies, participation of multidisciplinary urban stream experts from 5 continents, and input from the Austin community. Institutional barriers to community inclusion were identified and analyzed using real-world examples, both from the case studies and from the literature, which clarified disparities in power, equity, and values. Outcomes of the symposium have been aggregated into a vision that challenges the present institutional approach to urban stream management and a set of strategies to systematically address these barriers to improve restoration solutions. Integrating community members and other stakeholders throughout the urban restoration process, and a transparent decision-making process to resolve divergent objectives, can help identify appropriate goals for realizing both the ecological and social benefits of stream restoration
BRAF Mutations in Advanced Cancers: Clinical Characteristics and Outcomes
BACKGROUND: Oncogenic BRAF mutations have been found in diverse malignancies and activate RAF/MEK/ERK signaling, a critical pathway of tumorigenesis. We examined the clinical characteristics and outcomes of patients with mutant (mut) BRAF advanced cancer referred to phase 1 clinic. METHODS: We reviewed the records of 80 consecutive patients with mutBRAF advanced malignancies and 149 with wild-type (wt) BRAF (matched by tumor type) referred to the Clinical Center for Targeted Therapy and analyzed their outcome. RESULTS: Of 80 patients with mutBRAF advanced cancer, 56 had melanoma, 10 colorectal, 11 papillary thyroid, 2 ovarian and 1 esophageal cancer. Mutations in codon 600 were found in 77 patients (62, V600E; 13, V600K; 1, V600R; 1, unreported). Multivariate analysis showed less soft tissue (Odds ratio (OR) = 0.39, 95%CI: 0.20-0.77, P = 0.007), lung (OR = 0.38, 95%CI: 0.19-0.73, p = 0.004) and retroperitoneal metastases (OR = 0.34, 95%CI: 0.13-0.86, p = 0.024) and more brain metastases (OR = 2.05, 95%CI: 1.02-4.11, P = 0.043) in patients with mutBRAF versus wtBRAF. Comparing to the corresponding wtBRAF, mutBRAF melanoma patients had insignificant trend to longer median survival from diagnosis (131 vs. 78 months, p = 0.14), while mutBRAF colorectal cancer patients had an insignificant trend to shorter median survival from diagnosis (48 vs. 53 months, p = 0.22). In melanoma, V600K mutations in comparison to other BRAF mutations were associated with more frequent brain (75% vs. 36.3%, p = 0.02) and lung metastases (91.6% vs. 47.7%, p = 0.007), and shorter time from diagnosis to metastasis and to death (19 vs. 53 months, p = 0.046 and 78 vs. 322 months, p = 0.024 respectively). Treatment with RAF/MEK targeting agents (Hazard ratio (HR) = 0.16, 95%CI: 0.03-0.89, p = 0.037) and any decrease in tumor size after referral (HR = 0.07, 95%CI: 0.015-0.35, p = 0.001) correlated with longer survival in mutBRAF patients. CONCLUSIONS: BRAF appears to be a druggable mutation that also defines subgroups of patients with phenotypic overlap, albeit with differences that correlate with histology or site of mutation
Improving cancer symptom awareness and help-seeking among adults living in socioeconomically deprived communities in the UK using a facilitated health check: A protocol for the Awareness and Beliefs About Cancer (ABACus) Randomised Control Trial
Background: Cancer survival is lower in socioeconomically deprived communities, partly due to low awareness of symptoms, negative beliefs and delayed help-seeking. We developed an interactive health check questionnaire facilitated by trained lay advisors. It entails 29 questions about background, lifestyle and health with tailored behaviour change advice. Personalised results are printed using a traffic light (red/amber/green) system, highlighting areas where action should be taken. This is an individually randomised control trial to test effectiveness of the health check on symptom recognition. Methods: A total 246 participants aged 40+ years will be recruited from community and healthcare settings in socioeconomically deprived areas of Yorkshire and South Wales. Participants will be randomised to receive the health check or standard care (1:1 ratio). Outcome measures include: adapted Awareness and Beliefs about Cancer (primary outcome), brief State Trait Anxiety Inventory, intentions and motivation to adopt recommended health behaviours (early symptom presentation, cancer screening and lifestyle behaviours), adapted Client Service Receipt Inventory, brief medical history/screening and demographic questionnaire at: baseline; 2-weeks; and 6-months post-randomisation. A purposive sample of intervention sessions will be audio-recorded (n = 24) and half will additionally be observed (n = 12). Semi-structured interviews will take place at 2-weeks (n = 30) and 6-months (n = 15–20) post-randomisation. The primary analysis will compare cancer symptom recognition scores between arms at 2-weeks. Secondary analysis will assess cancer beliefs, barriers/time to presentation, screening and lifestyle behaviours, anxiety and costs. A process evaluation will assess intervention fidelity, dose and contamination. The London-Surrey NHS Research Ethics Committee (Ref: 17/LO/1507) approved this trial. Discussion: This is a trial of a theoretically underpinned complex intervention which has undergone phase 1 and 2 development work. The findings will evaluate evidence about the effect of the health check on symptom awareness. Although there are few exclusion criteria there are limitations regarding the population we are able to reach, who may have even higher risks of late diagnosis and poor cancer prognosis. However, the health check has the potential to improve cancer symptom awareness and encourage early help-seeking behaviour in deprived populations, thereby reducing inequalities in longer term cancer outcomes
Response of the primary tumor in symptomatic and asymptomatic stage IV colorectal cancer to combined interventional endoscopy and palliative chemotherapy
Applying Rasch analysis to evaluate measurement equivalence of different administration formats of the Activity Limitation scale of the Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR)
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