224 research outputs found

    Double-Talk Robust Fast Converging Algorithms for Network Echo Cancellation

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    Echo cancelers which cover longer impulse responses (greater than or equal to 64 ms) are desirable. Long responses create a need for more rapidly converging algorithms in order to meet the specifications for network echo cancelers devised by the ITU (International Telecommunication Union). In general, faster convergence implies a higher sensitivity to near-end disturbances, especially double-talk . Recently, a fast converging algorithm called proportionate NLMS (normalized least mean squares) algorithm (PNLMS) has been proposed. This algorithm exploits the sparseness of the echo path. In this paper we propose a method for making the PNLMS algorithm more robust against double-talk. The slower divergence rate of these robust algorithms in combination with a standard Geigel double-talk detector improves the performance of a network echo canceler considerably during double-talk. This results in the robust PNLMS algorithm which diverges much slower than PNLMS and standard NLMS. A generalization of the robust PNLMS algorithm to a robust proportionate affine projection algorithm (APA) is also presented. It converges very fast, and unlike PNLMS, is not as dependent on the assumption of a sparse echo path response. Trade off between convergence and divergence rate is easily tuned with one parameter and the added complexity is about 7 instructions per sample

    Mode of detection and breast cancer mortality by follow-up time and tumor characteristics among screened women in Cancer Prevention Study-II

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    Purpose: In a screened population, breast cancer-specific mortality is lower for screen-detected versus symptom-detected breast cancers; however, it is unclear whether this association varies by follow-up time and/or tumor characteristics. To further understand the prognostic utility of mode of detection, we examined its association with breast cancer-specific mortality, overall and by follow-up time, estrogen receptor status, tumor size, and grade. Methods: In the Cancer Prevention Study-II Nutrition Cohort, 3975 routinely screened women were diagnosed with invasive breast cancer (1992–2015). Among 2686 screen-detected and 1289 symptom-detected breast cancers, 206 and 209 breast cancer deaths, respectively, occurred up to 24 years post diagnosis. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated from Cox proportional hazard regression models. Results: Controlling for prognostic factors, symptom detection was associated with higher risk of breast cancer-specific death up to 5 years after diagnosis (HR≤5years = 1.88, 95% CI 1.21–2.91) this association was attenuated in subsequent follow-up (HR>5years = 1.26, 95% CI 0.98–1.63). Within tumor characteristic strata, there was a 1.3–2.7-fold higher risk of breast cancer death associated with symptom-detected cancers ≤ 5 years of follow-up, although associations were only significant for women with tumors < 2 cm (HR≤5years = 2.42, 95% CI 1.19–4.93) and for women with grade 1 or 2 tumors (HR≤5years = 2.72, 95% CI 1.33–5.57). In subsequent follow-up, associations were closer to the null. Conclusions: Screen detection is a powerful prognostic factor for short-term survival. Among women who survived at least 5 years after breast cancer diagnosis, other clinical factors may be more predictive of breast cancer survival

    Blockade of Fatty Acid Synthase Triggers Significant Apoptosis in Mantle Cell Lymphoma

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    Fatty acid synthase (FASN), a key player in the de novo synthetic pathway of long-chain fatty acids, has been shown to contribute to the tumorigenesis in various types of solid tumors. We here report that FASN is highly and consistently expressed in mantle cell lymphoma (MCL), an aggressive form of B-cell lymphoid malignancy. Specifically, the expression of FASN was detectable in all four MCL cell lines and 15 tumors examined. In contrast, benign lymphoid tissues and peripheral blood mononuclear cells from normal donors were negative. Treatment of MCL cell lines with orlistat, a FASN inhibitor, resulted in significant apoptosis. Knockdown of FASN expression using siRNA, which also significantly decreased the growth of MCL cells, led to a dramatic decrease in the cyclin D1 level. β-catenin, which has been previously reported to be upregulated in a subset of MCL tumors, contributed to the high level of FASN in MCL cells, Interesting, siRNA knock-down of FASN in turn down-regulated β-catenin. In conclusion, our data supports the concept that FASN contributes to the pathogenesis of MCL, by collaborating with β-catenin. In view of its high and consistent expression in MCL, FASN inhibitors may hold promises for treating MCL

    Phase I trial of intravesical Suramin in recurrent superficial transitional cell bladder carcinoma

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    Suramin is an antitrypanosomal agent with antineoplastic activity, but with serious systemic side effects. We administered Suramin intravesically to determine a concentration with low toxicity but with evidence of a pharmacodynamic effect, to recommend a dose level for phase II trials. This was an open-labelled, nonrandomised dose-escalation phase I study. In all, 12 patients with a history of recurrent superficial bladder cancer were grouped into four dose levels (10–150 mg ml−1 in 60 ml saline). Six catheter instillations at weekly intervals were used. Cystoscopy and biopsy were performed before and 3 months after the start of treatment. Suramin was assayed using high-performance liquid chromatography, vascular endothelial growth factor (VEGF) using ELISA (enzyme-linked immunosorbent assay), and urinary protein profile using surface-enhanced laser desorption ionisation mass spectroscopy (SELDI). Minimal systemic absorption of Suramin was found at the highest dose of 150 mg ml−1. Urinary VEGF was affected by Suramin at doses above 50 mg ml−1, corresponding to the estimated threshold of saturation of Suramin binding to urine albumin. SELDI showed a specific disappearance of urinary protein peaks during treatment. Intravesical Suramin shows lack of toxicity and low systemic absorption. The results of this phase I trial support expanded clinical trials of efficacy at a dose of 100 mg ml−1 intravesically

    Quality of life among Latina breast cancer patients: a systematic review of the literature

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    Introduction The Latino population is the most rapidly growing ethnic minority in the United States and Latinas have higher rates of advanced breast cancer and more rigorous treatments than White women. However, the literature lacks reviews on quality of life among this population of breast cancer patients. Methods A systematic review of the breast cancer quality of life (QOL) literature was conducted among studies that provided a comparison of mental, physical, social, or sexual QOL between Latinas and other racial/ethnic groups. Of the 375 studies reviewed, 20 quantitative studies and two qualitative studies met criteria for inclusion. Results Latinas were more likely to report poor mental, physical, and social QOL, relative to non-Latinas. Only four studies assessed sexual QOL, making it difficult to draw any conclusions. Of these four QOL domains, the largest disparity was found in the area of mental health in which Latinas reported poorer QOL compared to non-Latina Whites and Blacks. Discussion/conclusions Most quantitative studies revealed either that Latinas consistently evidenced significantly lower QOL than non-Latinas on all measures (6 studies) or reported mixed findings in which Latinas generally demonstrated significantly worse QOL on most, but not all, measures (12 studies) included in the study. Explanatory mechanisms including socio-demographic, treatment-related, and culturally-relevant factors are discussed. Implications for research design, measurement, and clinical work are also included. Implications for cancer survivors Although not entirely consistent, data suggest that Latina breast cancer survivors on average experience worse QOL than non-Latina Whites. Understanding ethnic differences in QOL among breast cancer survivors can inform interventions targeted at improving health status for Latinas

    Metabolic Regulation of Invadopodia and Invasion by Acetyl-CoA Carboxylase 1 and De novo Lipogenesis

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    Invadopodia are membrane protrusions that facilitate matrix degradation and cellular invasion. Although lipids have been implicated in several aspects of invadopodia formation, the contributions of de novo fatty acid synthesis and lipogenesis have not been defined. Inhibition of acetyl-CoA carboxylase 1 (ACC1), the committed step of fatty acid synthesis, reduced invadopodia formation in Src-transformed 3T3 (3T3-Src) cells, and also decreased the ability to degrade gelatin. Inhibition of fatty acid synthesis through AMP-activated kinase (AMPK) activation and ACC phosphorylation also decreased invadopodia incidence. The addition of exogenous 16∶0 and 18∶1 fatty acid, products of de novo fatty acid synthesis, restored invadopodia and gelatin degradation to cells with decreased ACC1 activity. Pharmacological inhibition of ACC also altered the phospholipid profile of 3T3-Src cells, with the majority of changes occurring in the phosphatidylcholine (PC) species. Exogenous supplementation with the most abundant PC species, 34∶1 PC, restored invadopodia incidence, the ability to degrade gelatin and the ability to invade through matrigel to cells deficient in ACC1 activity. On the other hand, 30∶0 PC did not restore invadopodia and 36∶2 PC only restored invadopodia incidence and gelatin degradation, but not cellular invasion through matrigel. Pharmacological inhibition of ACC also reduced the ability of MDA-MB-231 breast, Snb19 glioblastoma, and PC-3 prostate cancer cells to invade through matrigel. Invasion of PC-3 cells through matrigel was also restored by 34∶1 PC supplementation. Collectively, the data elucidate the novel metabolic regulation of invadopodia and the invasive process by de novo fatty acid synthesis and lipogenesis

    How many segments are there in an orange? Normative data for the new Cognitive Estimation Task in an Italian population

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    The Cognitive Estimation Test (CET) is widely used by clinicians to assess frontal executive dysfunction. In the present work, the Italian standardization of a new version of the CET is provided. This version consists of two 9-item parallel forms (A and B) that were administered to two hundred and twenty-seven healthy Italian male and female participants aged between 19 and 91 years with 5-24 years of full-time education. Performance on the CET was not related to age or level of education; both forms showed a male CET advantage. The new CET is a useful tool for clinicians and researchers to administer the CET more than once without practice effects, which is considered important when assessing frontal executive abilities

    Cortisol, cognition and the ageing prefrontal cortex

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    The structural and functional decline of the ageing human brain varies by brain region, cognitive function and individual. The underlying biological mechanisms are poorly understood. One potentially important mechanism is exposure to glucocorticoids (GCs; cortisol in humans); GC production is increasingly varied with age in humans, and chronic exposure to high levels is hypothesised to result in cognitive decline via cerebral remodelling. However, studies of GC exposure in humans are scarce and methodological differences confound cross-study comparison. Furthermore, there has been little focus on the effects of GCs on the frontal lobes and key white matter tracts in the ageing brain. This thesis therefore examines relationships among cortisol levels, structural brain measures and cognitive performance in 90 healthy, elderly community-dwelling males from the Lothian Birth Cohort 1936. Salivary cortisol samples characterised diurnal (morning and evening) and reactive profiles (before and after a cognitive test battery). Structural variables comprised Diffusion Tensor Imaging measures of major brain tracts and a novel manual parcellation method for the frontal lobes. The latter was based on a systematic review of current manual methods in the context of putative function and cytoarchitecture. Manual frontal lobe brain parcellation conferred greater spatial and volumetric accuracy when compared to both single- and multi-atlas parcellation at the lobar level. Cognitive ability was assessed via tests of general cognitive ability, and neuropsychological tests thought to show differential sensitivity to the integrity of frontal lobe sub-regions. The majority of, but not all frontal lobe test scores shared considerable overlap with general cognitive ability, and cognitive scores correlated most consistently with the volumes of the anterior cingulate. This is discussed in light of the diverse connective profile of the cingulate and a need to integrate information over more diffuse cognitive networks according to proposed de-differentiation or compensation in ageing. Individuals with higher morning, evening or pre-test cortisol levels showed consistently negative relationships with specific regional volumes and tract integrity. Participants whose cortisol levels increased between the start and end of cognitive testing showed selectively larger regional volumes and lower tract diffusivity (correlation magnitudes <.44). The significant relationships between cortisol levels and cognition indicated that flatter diurnal slopes or higher pre-test levels related to poorer test performance. In contrast, higher levels in the morning generally correlated with better scores (correlation magnitudes <.25). Interpretation of all findings was moderated by sensitivity to type I error, given the large number of comparisons conducted. Though there were limited candidates for mediation analysis, cortisol-function relationships were partially mediated by tract integrity (but not sub-regional frontal volumes) for memory and post-error slowing. This thesis offers a novel perspective on the complex interplay among glucocorticoids, cognition and the structure of the ageing brain. The findings suggest some role for cortisol exposure in determining age-related decline in complex cognition, mediated via brain structure
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