878 resultados para IMT-advanced


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Hot compression tests were carried out on 9Cr–Nb–V heat resistant steels in the temperature range of 600–1200 °C and the strain rate range of 10−2–100 s−1 to study their deformation characteristics. The full recrystallization temperature and the carbon-free bainite phase transformation temperature were determined by the slope-change points in the curve of mean flow stress versus the inverse of temperature. The parameters of the constitutive equation for the experimental steels were calculated, including the stress exponent and the activation energy. The lower carbon content in steel would increase the fraction of precipitates by increasing the volume of dynamic strain-induced (DSIT) ferrite during deformation. The ln(εc) versus ln(Z) and the ln(σc) versus ln(Z) plots for both steels have similar trends. The efficiency of power dissipation maps with instability maps merged together show excellent workability from the strain of 0.05 to 0.6. The microstructure of the experimental steels was fully recrystallized upon deformation at low Z value owing to the dynamic recrystallization (DRX), and exhibited a necklace structure under the condition of 1050 °C/0.1 s−1 due to the suppression of the secondary flow of DRX. However, there were barely any DRX grains but elongated pancake grains under the condition of 1000 °C/1 s−1 because of the suppression of the metadynamic recrystallization (MDRX).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In the production process of polyethylene terephthalate (PET) bottles, the initial temperature of preforms plays a central role on the final thickness, intensity and other structural properties of the bottles. Also, the difference between inside and outside temperature profiles could make a significant impact on the final product quality. The preforms are preheated by infrared heating oven system which is often an open loop system and relies heavily on trial and error approach to adjust the lamp power settings. In this paper, a radial basis function (RBF) neural network model, optimized by a two-stage selection (TSS) algorithm combined with partial swarm optimization (PSO), is developed to model the nonlinear relations between the lamp power settings and the output temperature profile of PET bottles. Then an improved PSO method for lamp setting adjustment using the above model is presented. Simulation results based on experimental data confirm the effectiveness of the modelling and optimization method.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background: Cancer cachexia is a complex metabolic syndrome characterised by severe and progressive weight loss which is predominantly muscle mass. It is a devastating complication of advanced cancer with profound bio-psycho-social implications for patients and their families. At present, there is no curative treatment for cachexia in advanced cancer therefore, the most important healthcare response entails the minimisation of the psycho-social distress associated with it. However, the literature suggests healthcare professionals’ are missing opportunities to respond to the multi-dimensional needs of this population.

Aim: The objective of this study was to explore healthcare professionals’ experience, understanding and perception of need of patients with advanced cancer who have cachexia and their families.

Methods: An interpretative qualitative approach based on symbolic interactionism was adopted. A purposive sample of doctors, nurses, specialist nurses, and dieticians were recruited from a cancer centre in a large teaching hospital in Northern Ireland. Data collection consisted of two phases: focus group interviews followed by individual semi-structured interviews.

Results: Findings from the focus group interviews were used as a framework for the semi structured interview schedule. Results centred on the influence of a variable combination of knowledge, culture, and resources on the management of cachexia in advanced cancer. Data revealed that variation in healthcare professionals’ perceptions of cachexia in advanced cancer, along with their professional ethos, influenced their response to it in clinical practice.

Conclusions: This study has revealed that cancer cachexia is a complex and challenging syndrome which needs to be addressed from a holistic model of care to reflect the multidimensional needs of patients and their families. Effective management will require a combination of knowledge, a supportive culture, and adequate resources.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background: Cancer cachexia is a complex metabolic syndrome characterised by severe and progressive weight loss which is predominantly muscle mass. It is a devastating and distressing complication of advanced cancer with profound bio-psycho-social implications for patients and their families. At present there is no curative treatment for cachexiain advanced cancer therefore the most important healthcare response entails the minimisation of the psycho-social distress associated with it. However the literature suggests healthcare professionals’are missing opportunities to intervene and respond to the multi-dimensional needs of this population.

Objective:The objective of this study was to explore healthcare professionals’ response to cachexia in advanced cancer.

Methods: An interpretative qualitative approach was adopted in this study. A purposive sample of doctors, nurses, specialist nurses and dieticians were recruited from a regional cancer centre between November 2009 and November 2010. Data was collection was twofold: two multi-professional focus groups were conducted first to uncover the main themes and issues in cachexia management. This data then informed the interview schedule for the following 25 individual semi-structured interviews.

Results: Preliminary data analysis of the semi-structured interviews revealed distinct differences between disciplines in their perceptions of cancer cachexia which influenced their response to it in clinical practice. The commonality between disciplines, with the exception of palliative care, was a reliance on the biomedical approach to cancer cachexia management.

Discussion and Conclusions: Cancer cachexia is a complex and challenging syndrome which needs to be addressed from a holistic model of care to reflect the multi-dimensional needs of this patient group. The perspectives of those involved in care delivery is required in order to inform the development of interventions aimed at minimising the distress associated with this devastating syndrome.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Aims/hypothesis
The receptor for AGEs (RAGE) is linked to proinflammatory pathology in a range of tissues. The objective of this study was to assess the potential modulatory role of RAGE in diabetic retinopathy.
Methods
Diabetes was induced in wild-type (WT) and Rage −/− mice (also known as Ager −/− mice) using streptozotocin while non-diabetic control mice received saline. For all groups, blood glucose, HbA1c and retinal levels of methylglyoxal (MG) were evaluated up to 24 weeks post diabetes induction. After mice were killed, retinal glia and microglial activation, vasopermeability, leucostasis and degenerative microvasculature changes were determined. 

Results
Retinal expression of RAGE in WT diabetic mice was increased after 12 weeks (p < 0.01) but not after 24 weeks. Rage −/− mice showed comparable diabetes but accumulated less MG and this corresponded to enhanced activity of the MG-detoxifying enzyme glyoxalase I in their retina when compared with WT mice. Diabetic Rage −/− mice showed significantly less vasopermeability, leucostasis and microglial activation (p < 0.05–0.001). Rage −/− mice were also protected against diabetes-related retinal acellular capillary formation (p < 0.001) but not against pericyte loss. 

Conclusions/interpretation Rage −/− in diabetic mice is protective against many retinopathic lesions, especially those related to innate immune responses. Inhibition of RAGE could be a therapeutic option to prevent diabetic retinopathy.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

By virtue of being a localized treatment modality, radiotherapy is unable to deliver a tumoricidal radiation dose to tissues outside of the irradiated field. Nevertheless, ionizing radiation may result in radiation damage mediated by a bystander like effect away from the irradiated field, but this response is likely to be modest when radiotherapy is the sole treatment modality. Over the last decade there has been a re-emergence of immune modulating therapies as anti-cancer treatment modalities. Clinical trials on vaccines have on the whole been largely disappointing, but greater response rates have been observed from the immune checkpoint modulators. A clinical benefit of using such agents has been shown in disease sites such as melanoma and non-small cell lung cancer. There is growing pre-clinical data and a number of case reports which suggest the presence of abscopal effects when radiotherapy is co-administered with immune checkpoint inhibitors, suggesting that this combination may lead to an enhanced tumour response outside of the primary treatment field. In this review, the mechanisms of such an enhanced out-of-field tumour response, the potential clinical utilities, the optimal radiotherapy delivery and considerations for clinical follow-up following treatment are discussed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The design optimization of cold-formed steel portal frame buildings is considered in this paper. The objective function is based on the cost of the members for the main frame and secondary members (i.e., purlins, girts, and cladding for walls and roofs) per unit area on the plan of the building. A real-coded niching genetic algorithm is used to minimize the cost of the frame and secondary members that are designed on the basis of ultimate limit state. It iis shown that the proposed algorithm shows effective and robust capacity in generating the optimal solution, owing to the population's diversity being maintained by applying the niching method. In the optimal design, the cost of purlins and side rails are shown to account for 25% of the total cost; the main frame members account for 27% of the total cost, claddings for the walls and roofs accounted for 27% of the total cost.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background: No studies have been conducted in the UK context to date that categorise medications in terms of appropriateness for patients with advanced dementia, or that examine medication use in these vulnerable patients.

Objectives: The objectives of this study were to categorise the appropriateness of a comprehensive list of medications and medication classes for use in patients with advanced dementia; examine the feasibility of conducting a longitudinal prospective cohort study to collect clinical and medication use data; and determine the appropriateness of prescribing for nursing home residents with advanced dementia in Northern Ireland (NI), using the categories developed.

Methods: A three-round Delphi consensus panel survey of expert clinicians was used to categorise the appropriateness of medications for patients with advanced dementia [defined as having Functional Assessment Staging (FAST) scores ranging from 6E to 7F]. This was followed by a longitudinal prospective cohort feasibility study that was conducted in three nursing homes in NI. Clinical and medication use for participating residents with advanced dementia (FAST scores ranging from 6E to 7F) were collected and a short test of dementia severity administered. These data were collected at baseline and every 3 months for up to 9 months or until death. For those residents who died during the study period, data were also collected within 14 days of death. The appropriateness ratings from the consensus panel survey were retrospectively applied to residents’ medication data at each data collection timepoint to determine the appropriateness of medications prescribed for these residents.

Results: Consensus was achieved for 87 (90 %) of the 97 medications and medication classes included in the survey. Fifteen residents were recruited to participate in the longitudinal prospective cohort feasibility study, four of whom died during the data collection period. Mean numbers of medications prescribed per resident were 16.2 at baseline, 19.6 at 3 months, 17.4 at 6 months and 16.1 at 9 months. Fourteen residents at baseline were taking at least one medication considered by the consensus panel to be never appropriate, and approximately 25 % of medications prescribed were considered to be never appropriate. Post-death data collection indicated a decrease in the proportion of never appropriate medications and an increase in the proportion of always appropriate medications for those residents who died.

Conclusions: This study is the first to develop and apply medication appropriateness indicators for patients with advanced dementia in the UK setting. The Delphi consensus panel survey of expert clinicians was a suitable method of developing such indicators. It is feasible to collect information on quality of life, functional performance, physical comfort, neuropsychiatric symptoms and cognitive function for this subpopulation of nursing home residents with advanced dementia.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Policymakers have largely replaced Single Bounded Discrete Choice (SBDC) valuation by the more statistically efficient repetitive methods; Double Bounded Discrete Choice (DBDC) and Discrete Choice Experiments (DCE) . Repetitive valuation permits classification into rational preferences: (i) a priori well-formed; (ii) consistent non-arbitrary values “discovered” through repetition and experience; (Plott, 1996; List 2003) and irrational preferences; (iii) consistent but arbitrary values as “shaped” by preceding bid level (Tufano, 2010; Ariely et al., 2003) and (iv) inconsistent and arbitrary values. Policy valuations should demonstrate behaviorally rational preferences. We outline novel methods for testing this in DBDC applied to renewable energy premiums in Chile.