119 resultados para Response analysis


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The purpose of this study was to compare the prostate-specific antigen (PSA) response to either neoadjuvant bicalutamide (BC) monotherapy or neoadjuvant luteinizing hormone-releasing hormone agonist (LHRHa) monotherapy and the subsequent effect on biochemical failure-free survival (BFFS) in men receiving radical radiotherapy (RT) for localized prostate cancer.

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Rice (Oryza sativa) varieties that are arsenate-tolerant (Bala) and -sensitive (Azucena) were used to conduct a transcriptome analysis of the response of rice seedlings to sodium arsenate (AsV) in hydroponic solution. RNA extracted from the roots of three replicate experiments of plants grown for 1 week in phosphate-free nutrient with or without 13.3 muM AsV was used to challenge the Affymetrix (52K) GeneChip Rice Genome array. A total of 576 probe sets were significantly up-regulated at least 2-fold in both varieties, whereas 622 were down-regulated. Ontological classification is presented. As expected, a large number of transcription factors, stress proteins, and transporters demonstrated differential expression. Striking is the lack of response of classic oxidative stress-responsive genes or phytochelatin synthases/synthatases. However, the large number of responses from genes involved in glutathione synthesis, metabolism, and transport suggests that glutathione conjugation and arsenate methylation may be important biochemical responses to arsenate challenge. In this report, no attempt is made to dissect differences in the response of the tolerant and sensitive variety, but analysis in a companion article will link gene expression to the known tolerance loci available in the BalaxAzucena mapping population.

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A three-dimensional continuum damage mechanics-based material model was implemented in an implicit Finite Element code to simulate the progressive intralaminar degradation of fibre reinforced laminates based on ply failure mechanisms. This paper presents some structural applications of the progressive failure model implemented. The focus is on the non-linear response of the shear failure mode and its interaction with other failure modes. Structural applications of the damage model show that the proposed model is able to reproduce failure loads and patterns observed experimentally.

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In response to claims that the quality (and in particular linearity) of children's mental representation of number acts as a constraint on number development, we carried out a longitudinal assessment of the relationships between number line estimation, counting, and mathematical abilities. Ninety-nine 5-year-olds were tested on 4 occasions at 3 monthly intervals. Correlations between the 3 types of ability were evident, but while the quality of children's estimations changed over time and performance on the mathematical tasks improved over the same period, changes in one were not associated with changes in the other. In contrast to the earlier claims that the linearity of number representation is potentially a unique contributor to children's mathematical development, the data suggest that this variable is not significantly privileged in its impact over and above simple procedural number skills. We propose that both early arithmetic success and estimating skill are bound closely to developments in counting ability.

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The termination of stiffeners in composite aircraft structures give rise to regions of high interlaminar shear and peel stresses as the load in the stiffener is diffused into the skin. This is of particular concern in co-cured composite stiffened structures where there is a relatively low resistance to through-thickness stress components at the skin-stiffener interface. In Part I, experimental results of tested specimens highlighted the influence of local design parameters on their structural response. Indeed some of the observed behavior was unexpected. There is a need to be able to analyse a range of changes in geometry rapidly to allow the analysis to form an integral part of the structural design process.

This work presents the development of a finite element methodology for modelling the failure process of these critical regions. An efficient thick shell element formulation is presented and this element is used in conjuction with the Virtual Crack Closure Technique (VCCT) to predict the crack growth characteristics of the modelled specimens. Three specimens were modelled and the qualitative aspects of crack growth were captured successfully. The shortcomings in the quantitative correlation between the predicted and observed failure loads are discussed. There was evidence to suggest that high through-thickness compressive stresses enhanced the fracture toughness in these critical regions.

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It is well known that shape corrections have to be applied to the local-density (LDA) and generalized gradient (GGA) approximations to the Kohn-Sham exchange-correlation potential in order to obtain reliable response properties in time dependent density functional theory calculations. Here we demonstrate that it is an oversimplified view that these shape corrections concern primarily the asymptotic part of the potential, and that they affect only Rydberg type transitions. The performance is assessed of two shape-corrected Kohn-Sham potentials, the gradient-regulated asymptotic connection procedure applied to the Becke-Perdew potential (BP-GRAC) and the statistical averaging of (model) orbital potentials (SAOP), versus LDA and GGA potentials, in molecular response calculations of the static average polarizability alpha, the Cauchy coefficient S-4, and the static average hyperpolarizability beta. The nature of the distortions of the LDA/GGA potentials is highlighted and it is shown that they introduce many spurious excited states at too low energy which may mix with valence excited states, resulting in wrong excited state compositions. They also lead to wrong oscillator strengths and thus to a wrong spectral structure of properties like the polarizability. LDA, Becke-Lee-Yang-Parr (BLYP), and Becke-Perdew (BP) characteristically underestimate contributions to alpha and S-4 from bound Rydberg-type states and overestimate those from the continuum. Cancellation of the errors in these contributions occasionally produces fortuitously good results. The distortions of the LDA, BLYP, and BP spectra are related to the deficiencies of the LDA/GGA potentials in both the bulk and outer molecular regions. In contrast, both SAOP and BP-GRAC potentials produce high quality polarizabilities for 21 molecules and also reliable Cauchy moments and hyperpolarizabilities for the selected molecules. The analysis for the N-2 molecule shows, that both SAOP and BP-GRAC yield reliable energies omega(i) and oscillator strengths f(i) of individual excitations, so that they reproduce well the spectral structure of alpha and S-4.(C) 2002 American Institute of Physics.

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Infected airway epithelial cells up-regulate the expression of chemokines, chiefly IL-8, and antimicrobial molecules including ß-defensins (BD). Acinetobacter baumannii is a cause of hospital-acquired pneumonia. We examined whether A. baumannii induced the expressions of IL-8 and BD2 by airway epithelial cells and the receptors implicated in bacterial detection. A549 and human primary airway cells released IL-8 upon infection. A. baumannii-infected cells also increased the expression of BD2 which killed A. baummannii strains. IL-8 induction was via NF-B and mitogen-activated kinases p38 and p44/42-dependent pathways. A. baumannii engaged Toll-like receptor (TLR) 2 and TLR4 pathways and A549 cells could use soluble CD14 as TLRs co-receptor. A. baumannii lipopolysaccharide stimulated IL-8 release by A549 cells and sCD14 facilitated the recognition of the lipopolysaccharide. Mass spectrometry analysis revealed that A. baumannii lipid A structure matches those with endotoxic potential. These results demonstrate that airway epithelial cells produce mediators important for A. baumannii clearance. © 2010 March et al.

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Purpose/Objectives: To explore healthcare professionals' experience, understanding, and perception of the needs of patients with cachexia in advanced cancer.

Research Approach: A qualitative approach based on symbolic interactionism.

Setting: A regional cancer center in a large teaching hospital in the United Kingdom.

Participants: 34 healthcare professionals who had experience providing care to patients with cachexia in advanced cancer.

Methodologic Approach: Data collection consisted of two phases: focus group and semistructured interviews. Interviews were digitally recorded and transcribed verbatim for analysis. This article reports on findings from the second phase of data collection.

Findings: Analysis revealed that professional approaches to cachexia were influenced by three overarching and interthinking themes: knowledge, culture, and resources. Healthcare professionals commonly recognized the impact of the syndrome; however, for nonpalliative healthcare professionals, a culture of avoidance and an overreliance on the biomedical model of care had considerable influence on the management of cachexia in patients with advanced cancer.

Conclusions: Cachexia management in patients with advanced cancer can be difficult and is directed by a variable combination of the influence of knowledge, culture of the clinical area, and available resources. Distinct differences exist in the management of cachexia among palliative and nonpalliative care professionals.

Interpretation: This study presented a multiprofessional perspective on the management of cachexia in patients with advanced cancer and revealed that cachexia is a complex and challenging syndrome that needs to be addressed from a holistic model of care.

Knowledge Translation: Cachexia management in patients with advanced cancer is complex and challenging and is directed by a combination of variables. An overreliance on the biomedical model of health and illness occurs in the management of cachexia in patients with advanced cancer. Cachexia needs to be addressed from a holistic model of care to reflect the multidimensional needs of patients and their families.

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The purpose of the present study was to examine the role of a rapid access home-based service as a means for the elderly to avoid admission to an acute-care hospital. The setting for the study included emergency departments in three acute care hospitals and a home care program in a mid-size Canadian city. Multiple sources of information were obtained to evaluate the service. Hospital emergency department records and home care records were reviewed. Patients who participated in the service (n=96) and physicians and nurses (n =119) who had involvement with the service were surveyed appraising the service in terms of relevance, access, quality and coordination. Study results revealed that elderly women with multiple health problems who lived alone were the most frequent users of the service. The majority of the patients admitted to the service presented with problems of a functional nature that were the result of a fall or mobility problems. The results indicated that the service did avert hospital admissions and facilitated a process by which patients could avoid the intermediate step of hospitalization before placed in a higher level of care or returning to previous levels of functioning. Economic analysis indicated that the value of the service stemmed from the benefits to patients and caregivers rather than from cost savings offered to acute care hospitals.

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Background: An increasingly significant public health issue in Canada, and elsewhere throughout the developed world, pertains to the provision of adequate palliative/end-of-life (P/EOL) care. Informal caregivers who take on the responsibility of providing P/EOL care often experience negative physical, mental, emotional, social and economic consequences. In this article, we specifically examine how Canada's Compassionate Care Benefit (CCB) - a contributory benefits social program aimed at informal P/EOL caregivers - operates as a public health response in sustaining informal caregivers providing P/EOL care, and whether or not it adequately addresses known aspects of caregiver burden that are addressed within the population health promotion (PHP) model. Methods. As part of a national evaluation of Canada's Compassionate Care Benefit, 57 telephone interviews were conducted with Canadian informal P/EOL caregivers in 5 different provinces, pertaining to the strengths and weaknesses of the CCB and the general caregiving experience. Interview data was coded with Nvivo software and emerging themes were identified by the research team, with such findings published elsewhere. The purpose of the present analysis was identified after comparing the findings to the literature specific to caregiver burden and public health, after which data was analyzed using the PHP model as a guiding framework. Results: Informal caregivers spoke to several of the determinants of health outlined in the PHP model that are implicated in their burden experience: gender, income and social status, working conditions, health and social services, social support network, and personal health practises and coping strategies. They recognized the need for improving the CCB to better address these determinants. Conclusions: This study, from the perspective of family caregivers, demonstrates that the CCB is not living up to its full potential in sustaining informal P/EOL caregivers. Effort is required to transform the CCB so that it may fulfill the potential it holds for serving as one public health response to caregiver burden that forms part of a healthy public policy that addresses the determinants of this burden. © 2011 Williams et al; licensee BioMed Central Ltd.

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Nurses have key roles in the coordination and delivery of community-based palliative care. The purpose of this study was to examine the differences between rural and urban community nurses' delivery of palliative care services. A survey was distributed to 277 nurses employed by a community agency in Ontario, Canada, and a 60% response rate was obtained. Nurses reported spending 27% of their time providing palliative care. Rural and urban nurses had similar roles in palliative care but rural nurses spent more time travelling and were more confident in their ability to provide palliative care. Both groups of nurses reported moderate job satisfaction and moderate satisfaction with the level of interdisciplinary collaboration in their practice. Several barriers to and facilitators of optimal palliative care provision were identified. The study results provide information about the needs of nurses that practise in these settings and may provide a basis for the development of strategies to address these needs.

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Virus infection-induced global protein synthesis suppression is linked to assembly of stress granules (SGs), cytosolic aggregates of stalled translation preinitiation complexes. To study long-term stress responses, we developed an imaging approach for extended observation and analysis of SG dynamics during persistent hepatitis C virus (HCV) infection. In combination with type 1 interferon, HCV infection induces highly dynamic assembly/disassembly of cytoplasmic SGs, concomitant with phases of active and stalled translation, delayed cell division, and prolonged cell survival. Double-stranded RNA (dsRNA), independent of viral replication, is sufficient to trigger these oscillations. Translation initiation factor eIF2a phosphorylation by protein kinase R mediates SG formation and translation arrest. This is antagonized by the upregulation of GADD34, the regulatory subunit of protein phosphatase 1 dephosphorylating eIF2a. Stress response oscillation is a general mechanism to prevent long-lasting translation repression and a conserved host cell reaction to multiple RNA viruses, which HCV may exploit to establish persistence.

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Objective The phenotype of the antioxidant and pro-angiogenicprotein haptoglobin (Hp) predicts cardiovascular disease risk andtreatment response to antioxidant vitamins in individuals withdiabetes. Our objective was to determine whether Hp phenotypeinfluences pre-eclampsia risk, or the efficacy of vitamins C and Ein preventing pre-eclampsia, in women with type-1 diabetes.
Design This is a secondary analysis of a randomised controlledtrial in which women with diabetes received daily vitamins C andE, or placebo, from 8 to 22 weeks of gestation until delivery.
Setting Twenty-five antenatal metabolic clinics across the UK (innorth-west England, Scotland, and Northern Ireland).
Population Pregnant women with type-1 diabetes.
Methods Hp phenotype was determined in white women whocompleted the study and had plasma samples available (n = 685).
Main outcome measure Pre-eclampsia.
Results Compared with Hp 2-1, Hp 1-1 (OR 0.59, 95% CI 0.30–1.16) and Hp 2-2 (OR 0.93, 95% CI 0.60–1.45) were notassociated with significantly decreased pre-eclampsia risk afteradjusting for treatment group and HbA1c at randomisation. Ourstudy was not powered to detect an interaction between Hpphenotype and treatment response; however, our preliminaryanalysis sugge sts that vitamins C and E did not prevent pre-eclampsia in women of any Hp phenotype (Hp 1-1, OR 0.77, 95%CI 0.22–2.71; Hp 2-1, OR 0.81, 95% CI 0.46–1.43; Hp 2-2, 0.67,95% CI 0.34–1.33), after adjusting for HbA1c at randomisation.
Conclusions The Hp phenotype did not significantly affect pre-eclampsia risk in women with type-1 diabetes.


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The temporal analysis of products (TAP) technique was successfully applied for the first time to investigate the reverse water-gas shift (RWGS) reaction over a 2% Pt/CeO2 catalyst. The adsorption/desorption rate constants for CO2 and H-2 were determined in separate TAP pulse-response experiments, and the number of H-containing exchangeable species was determined using D-2 multipulse TAP experiments. This number is similar to the amount of active sites observed in previous SSITKA experiments. The CO production in the RWGS reaction was studied in a TAP experiment using separate (sequential) and simultaneous pulsing Of CO2 and H-2. A small yield of CO was observed when CO2 was pulsed alone over the reduced catalyst, whereas a much higher CO yield was observed when CO2 and H-2 were pulsed consecutively. The maximum CO yield was observed when the CO2 pulse was followed by a H-2 pulse with only a short (1 s) delay. Based on these findings, we conclude that an associative reaction mechanism dominates the RWGS reaction under these experimental conditions. The rate constants for several elementary steps can be determined from the TAP data. In addition, using a difference in the time scale of the separate reaction steps identified in the TAP experiments, it is possible to distinguish a number of possible reaction pathways. (c) 2005 Elsevier Inc. All rights reserved.