1,575 research outputs found
The fibre of a pinch map in a model category
In the category of pointed topological spaces, let F be the homotopy fibre of the
pinching map X ∪ CA → X ∪ CA/ X from the mapping cone on a cofibration A → X
onto the suspension of A. Gray (Proc Lond Math Soc (3) 26:497–520, 1973) proved
that F is weakly homotopy equivalent to the reduced product (X, A)∞. In this paper
we prove an analogue of this phenomenon in a model category, under suitable
conditions including a cube axiom.Web of Scienc
A study of the effect of thickness on the thermal degradation and flammability characteristics of some composite materials using a cone calorimeter
An international randomised controlled trial to compare targeted intra-operative radiotherapy (TARGIT) with conventional post-operative radiotherapy after conservative breast surgery for women with early stage breast cancer (The TARGIT-A trial)
BACKGROUND: Based on our laboratory work and clinical trials we hypothesised that radiotherapy after lumpectomy for breast cancer could be restricted to the tumour bed. In collaboration with the industry we developed a new radiotherapy device and a new surgical operation for delivering single-dose radiation to the tumour bed - the tissues at highest risk of local recurrence. We named it TARGeted Intraoperative radioTherapy (TARGIT). From 1998 we confirmed its feasibility and safety in pilot studies. OBJECTIVE: To compare TARGIT within a risk-adapted approach with whole breast external beam radiotherapy over several weeks (EBRT). DESIGN AND SETTING: The TARGIT-A trial was a pragmatic, prospective, international, multicenter, non-inferiority, non-blinded, randomised (1:1 ratio), clinical trial from 33 centres in 11 countries. Originally, randomisation occurred before initial lumpectomy (prepathology) and if allocated TARGIT, the patient received it during the lumpectomy. Subsequently, the postpathology stratum was added, in which randomisation occurred after initial lumpectomy, allowing potentially easier logistics and a more stringent case selection, but needed a reoperation to reopen the wound to give TARGIT as delayed procedure. Risk-adapted approach meant that in the experimental arm, if pre-specified unsuspected adverse factors were found postoperatively after receiving TARGIT, then EBRT was recommended. Pragmatically, this reflected how TARGIT would be practiced in the real world. PARTICIPANTS: Women who were >=45 years of age with unifocal invasive ductal carcinoma preferably <= 3.5cm in size; 3451 patients were recruited between March 2000 and June 2012. OUTCOMES: Primary: absolute difference in local recurrence, with a non-inferiority margin of 2.5%. Secondary: included toxicity, breast cancer specific and non-breast-cancer mortality. RESULTS: Values below are 5-year Kaplan-Meier rates for TARGIT vs. EBRT. There was no statistically significant difference in local recurrence between TARGIT and EBRT. TARGIT was non-inferior to EBRT overall (3·3%(2·1–5·1) vs. 1·3%(0·7–2·5),p=0.04,Pnoninferiority =0.00000012) and in the prepathology stratum(n=2298) when TARGIT was given concurrently with lumpectomy(2·1%(1·1–4·2) vs. 1·1%(0·5–2·5),p=0.31,Pnoninferiority =0.0000000013). With delayed TARGIT postpathology,(n=1153) the between-group difference was larger than 2·5% and non-inferiority was not established for this stratum((5·4%(3·0–9·7) vs. 1·7%(0·6–4·9),p=0.069,Pnoninferiority= 0.06640). The local-recurrence-free survival when TARGIT was given with lumpectomy was 93.9%(95%CI 90.9 – 95.9) vs. EBRT: 92.5%(95%CI 89.7 – 94.6),p=0.35. In a planned subgroup analysis, progesterone (PgR) receptor status was found to be the only predictor of outcome - hormone responsive patients (PgRpositive) had similar 5-year local recurrence with TARGIT during lumpectomy 1.4%(0.5-3.9) vs. EBRT 1.2%(0.5-2.9),p=0.77. Grade 3 or 4 radiotherapy toxicity was significantly reduced with TARGIT. Overall, breast cancer mortality was much the same between groups (2·6%[1·5–4·3] vs. 1·9%[1·1–3·2];p=0·56) but there were significantly fewer non-breast-cancer deaths with TARGIT (1·4% [0·8–2·5] vs 3·5%[2·3–5·2];p=0·0086), attributable to fewer deaths from cardiovascular causes and other cancers, leading to a trend in reduced overall mortality in the TARGIT arm 37 deaths, 3·9%(2·7–5·8) vs. 51 deaths, 5·3%(3·9–7·3),p=0.099). Health economic analyses suggest that TARGIT was statistically significantly less costly than EBRT, produced similar QALYs, had a positive incremental Net Monetary Benefit that was borderline statistically significant from zero, and had a probability of over 90% of being cost-effective. There appears to be little uncertainty in the point estimates, based on deterministic and probabilistic sensitivity analyses. If TARGIT were given instead of EBRT in suitable patients, it might potentially reduce costs to the health care providers by £8 million to £9.1 million each year. This does not include environmental, patient and societal costs. LIMITATIONS: The number of local recurrences is small however, the number of events for local-recurrence-free survival is not small (59 vs. 61); Occurrence of only a few events implies that the treatments are effective and any difference is unlikely to be large. The follow up not all 3451 patients is 5 years, although the number required to answer the main trial question (n=585) have more than 5 years follow up. FUTURE WORK: We shall repeat the analyses with longer follow up. Although this may not change the primary result, the larger number of events may confirm the effect on mortality and allow more detailed subgroup analyses. The TARGIT-B trial is testing whether TARGIT-Boost is superior to EBRT boost. CONCLUSION: For patients with breast cancer (women who are 45 years of age and older with hormone sensitive invasive ductal carcinoma that is up to 3.5cm in size), TARGIT concurrent with lumpectomy within a risk-adapted approach is as effective, safer and less expensive alternative to postoperative EBRT. TRIAL REGISTRATION: ISRCTN34086741, ClinicalTrials.gov NCT00983684
Adverse environmental conditions influence age-related innate immune responsiveness
BACKGROUND-: The innate immune system plays an important role in the recognition and induction of protective responses against infectious pathogens, whilst there is increasing evidence for a role in mediating chronic inflammatory diseases at older age. Despite indications that environmental conditions can influence the senescence process of the adaptive immune system, it is not known whether the same holds true for the innate immune system. Therefore we studied whether age-related innate immune responses are similar or differ between populations living under very diverse environmental conditions. METHODS-: We compared cross-sectional age-related changes in ex vivo innate cytokine responses in a population living under affluent conditions in the Netherlands (age 20–68 years old, n = 304) and a population living under adverse environmental conditions in Ghana (age 23–95 years old, n = 562). RESULTS-: We found a significant decrease in LPS-induced Interleukin (IL)-10 and Tumor Necrosis Factor (TNF) production with age in the Dutch population. In Ghana a similar age-related decline in IL-10 responses to LPS, as well as to zymosan, or LPS plus zymosan, was observed. TNF production, however, did not show an age-associated decline, but increased significantly with age in response to co-stimulation with LPS and zymosan. CONCLUSION-: We conclude that the decline in innate cytokine responses is an intrinsic ageing phenomenon, while pathogen exposure and/or selective survival drive pro-inflammatory responses under adverse living conditions
Chaos game representation for comparison of whole genomes
BACKGROUND: Chaos game representation of genome sequences has been used for visual representation of genome sequence patterns as well as alignment-free comparisons of sequences based on oligonucleotide frequencies. However the potential of this representation for making alignment-based comparisons of whole genome sequences has not been exploited. RESULTS: We present here a fast algorithm for identifying all local alignments between two long DNA sequences using the sequence information contained in CGR points. The local alignments can be depicted graphically in a dot-matrix plot or in text form, and the significant similarities and differences between the two sequences can be identified. We demonstrate the method through comparison of whole genomes of several microbial species. Given two closely related genomes we generate information on mismatches, insertions, deletions and shuffles that differentiate the two genomes. CONCLUSION: Addition of the possibility of large scale sequence alignment to the repertoire of alignment-free sequence analysis applications of chaos game representation, positions CGR as a powerful sequence analysis tool
Activation of Human Stearoyl-Coenzyme A Desaturase 1 Contributes to the Lipogenic Effect of PXR in HepG2 Cells
The pregnane X receptor (PXR) was previously known as a xenobiotic receptor. Several recent studies suggested that PXR also played an important role in lipid homeostasis but the underlying mechanism remains to be clearly defined. In this study, we found that rifampicin, an agonist of human PXR, induced lipid accumulation in HepG2 cells. Lipid analysis showed the total cholesterol level increased. However, the free cholesterol and triglyceride levels were not changed. Treatment of HepG2 cells with rifampicin induced the expression of the free fatty acid transporter CD36 and ABCG1, as well as several lipogenic enzymes, including stearoyl-CoA desaturase-1 (SCD1), long chain free fatty acid elongase (FAE), and lecithin-cholesterol acyltransferase (LCAT), while the expression of acyl:cholesterol acetyltransferase(ACAT1) was not affected. Moreover, in PXR over-expressing HepG2 cells (HepG2-PXR), the SCD1 expression was significantly higher than in HepG2-Vector cells, even in the absence of rifampicin. Down-regulation of PXR by shRNA abolished the rifampicin-induced SCD1 gene expression in HepG2 cells. Promoter analysis showed that the human SCD1 gene promoter is activated by PXR and a novel DR-7 type PXR response element (PXRE) response element was located at -338 bp of the SCD1 gene promoter. Taken together, these results indicated that PXR activation promoted lipid synthesis in HepG2 cells and SCD1 is a novel PXR target gene. © 2013 Zhang et al
Salience-based selection: attentional capture by distractors less salient than the target
Current accounts of attentional capture predict the most salient stimulus to be invariably selected first. However, existing salience and visual search models assume noise in the map computation or selection process. Consequently, they predict the first selection to be stochastically dependent on salience, implying that attention could even be captured first by the second most salient (instead of the most salient) stimulus in the field. Yet, capture by less salient distractors has not been reported and salience-based selection accounts claim that the distractor has to be more salient in order to capture attention. We tested this prediction using an empirical and modeling approach of the visual search distractor paradigm. For the empirical part, we manipulated salience of target and distractor parametrically and measured reaction time interference when a distractor was present compared to absent. Reaction time interference was strongly correlated with distractor salience relative to the target. Moreover, even distractors less salient than the target captured attention, as measured by reaction time interference and oculomotor capture. In the modeling part, we simulated first selection in the distractor paradigm using behavioral measures of salience and considering the time course of selection including noise. We were able to replicate the result pattern we obtained in the empirical part. We conclude that each salience value follows a specific selection time distribution and attentional capture occurs when the selection time distributions of target and distractor overlap. Hence, selection is stochastic in nature and attentional capture occurs with a certain probability depending on relative salience
Methods for confidence interval estimation of a ratio parameter with application to location quotients
BACKGROUND: The location quotient (LQ) ratio, a measure designed to quantify and benchmark the degree of relative concentration of an activity in the analysis of area localization, has received considerable attention in the geographic and economics literature. This index can also naturally be applied in the context of population health to quantify and compare health outcomes across spatial domains. However, one commonly observed limitation of LQ is its widespread use as only a point estimate without an accompanying confidence interval. METHODS: In this paper we present statistical methods that can be used to construct confidence intervals for location quotients. The delta and Fieller's methods are generic approaches for a ratio parameter and the generalized linear modelling framework is a useful re-parameterization particularly helpful for generating profile-likelihood based confidence intervals for the location quotient. A simulation experiment is carried out to assess the performance of each of the analytic approaches and a health utilization data set is used for illustration. RESULTS: Both the simulation results as well as the findings from the empirical data show that the different analytical methods produce very similar confidence limits for location quotients. When incidence of outcome is not rare and sample sizes are large, the confidence limits are almost indistinguishable. The confidence limits from the generalized linear model approach might be preferable in small sample situations. CONCLUSION: LQ is a useful measure which allows quantification and comparison of health and other outcomes across defined geographical regions. It is a very simple index to compute and has a straightforward interpretation. Reporting this estimate with appropriate confidence limits using methods presented in this paper will make the measure particularly attractive for policy and decision makers
Reversal of isolated unilateral optic nerve edema with concomitant visual impairment following blunt trauma: a case report
<p>Abstract</p> <p>Introduction</p> <p>Serious injury to the optic nerve is an uncommon entity but may result in permanent visual disability. Isolated trauma of the optic nerve is usually associated with blunt skull trauma involving fractures of both skull and optic canal, but may also occur from blunt ocular trauma.</p> <p>Case presentation</p> <p>We report a woman who developed isolated unilateral optic nerve edema with corresponding visual deficits after a rear-end collision accident. She was treated with corticosteroids and had a favourable outcome.</p> <p>Conclusion</p> <p>The approach described here was successful in this case but the current body of evidence still lacks a validated approach to the management of traumatic optic neuropathy and each case needs to be individually assessed.</p
Happiness matters : exploring the linkages between personality, personal happiness, and work-related psychological health among priests and sisters in Italy
This study responds to the challenge posed by Rossetti’s work to explore the antecedents and consequences of individual differences in happiness among priests and religious sisters. The Oxford Happiness Questionnaire was completed together with measures of personality and work-related psychological health by 95 priests and 61 religious sisters. Overall the data demonstrated high levels of personal happiness among priests and religious sisters, but also significant signs of vulnerability. Personality provided significant prediction of individual differences in both personal happiness and work-related psychological health. However, personal happiness provided additional protection against work-related emotional exhaustion and additional enhancement of work-related satisfaction. These findings suggest that acknowledging and affirming personal happiness may enhance the work-related psychological health of Catholic priests and religious sisters
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