985 resultados para electronic stopping power


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Positron emission tomography with [18F] fluorodeoxyglucose (FDG-PET) plays a well-established role in assisting early detection of frontotemporal lobar degeneration (FTLD). Here, we examined the impact of intensity normalization to different reference areas on accuracy of FDG-PET to discriminate between patients with mild FTLD and healthy elderly subjects. FDG-PET was conducted at two centers using different acquisition protocols: 41 FTLD patients and 42 controls were studied at center 1, 11 FTLD patients and 13 controls were studied at center 2. All PET images were intensity normalized to the cerebellum, primary sensorimotor cortex (SMC), cerebral global mean (CGM), and a reference cluster with most preserved FDG uptake in the aforementioned patients group of center 1. Metabolic deficits in the patient group at center 1 appeared 1.5, 3.6, and 4.6 times greater in spatial extent, when tracer uptake was normalized to the reference cluster rather than to the cerebellum, SMC, and CGM, respectively. Logistic regression analyses based on normalized values from FTLD-typical regions showed that at center 1, cerebellar, SMC, CGM, and cluster normalizations differentiated patients from controls with accuracies of 86%, 76%, 75% and 90%, respectively. A similar order of effects was found at center 2. Cluster normalization leads to a significant increase of statistical power in detecting early FTLD-associated metabolic deficits. The established FTLD-specific cluster can be used to improve detection of FTLD on a single case basis at independent centers - a decisive step towards early diagnosis and prediction of FTLD syndromes enabling specific therapies in the future.

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This school in the course of Marketing Business Management and specifically Entrepr This school in the course of Marketing Business Management and specifically Entrepreneurship in the discipline of Simulation - Games Marketing year was accordingly for the creation of a company in the computer business in business online simulator called Marketplace, in order to put into practice all the theoretical knowledge acquired during all previous semesters. This platform we were confronted with decisions in eight quarters corresponding 4 every year , in order to encourage learning in a practical way, a virtual and dynamic environment. Every quarter acareados with well organized tasks taking as a reference point defined strategies such as market research analysis, branding , store management after its creation , development of the policy of the 4Ps , identifying opportunities , monitoring of finances and invest heavily . All quarters were subjected decisions and are then given the results , such as: market performance , financial performance, investments in the future , the "health" of the company 's marketing efficiency then analyzed by our company , teaching and also by competition Balanced Scorecard ie , semi-annual and cumulative . For the start of activities it was awarded the 1st year a total of 2,000,000, corresponding to 500,000 out of 4 first quarter , and 5,000,000 in the fifth quarter in a total of 7,000,000 . The capital invested was used to buy market research, opening sales offices , create brands , contract sales force , advertise products created and perform activity R & D in order to make a profit and become self- sufficient to guarantee the payment of principal invested to headquarters ( Corporate Headquarters ) .

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This study aims to design a wearable system for kinetics measurement of multi-segment foot joints in long-distance walking and to investigate its suitability for clinical evaluations. The wearable system consisted of inertial sensors (3D gyroscopes and 3D accelerometers) on toes, forefoot, hindfoot, and shank, and a plantar pressure insole. After calibration in a laboratory, 10 healthy elderly subjects and 12 patients with ankle osteoarthritis walked 50m twice wearing this system. Using inverse dynamics, 3D forces, moments, and power were calculated in the joint sections among toes, forefoot, hindfoot, and shank. Compared to those we previously estimated for a one-segment foot model, the sagittal and transverse moments and power in the ankle joint, as measured via multi-segment foot model, showed a normalized RMS difference of less than 11%, 14%, and 13%, respectively, for healthy subjects, and 13%, 15%, and 14%, for patients. Similar to our previous study, the coronal moments were not analyzed. Maxima-minima values of anterior-posterior and vertical force, sagittal moment, and power in shank-hindfoot and hindfoot-forefoot joints were significantly different between patients and healthy subjects. Except for power, the inter-subject repeatability of these parameters was CMC>0.90 for healthy subjects and CMC>0.70 for patients. Repeatability of these parameters was lower for the forefoot-toes joint. The proposed measurement system estimated multi-segment foot joints kinetics with acceptable repeatability but showed difference, compared to those previously estimated for the one-segment foot model. These parameters also could distinguish patients from healthy subjects. Thus, this system is suggested for outcome evaluations of foot treatments.

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Given the adverse impact of image noise on the perception of important clinical details in digital mammography, routine quality control measurements should include an evaluation of noise. The European Guidelines, for example, employ a second-order polynomial fit of pixel variance as a function of detector air kerma (DAK) to decompose noise into quantum, electronic and fixed pattern (FP) components and assess the DAK range where quantum noise dominates. This work examines the robustness of the polynomial method against an explicit noise decomposition method. The two methods were applied to variance and noise power spectrum (NPS) data from six digital mammography units. Twenty homogeneously exposed images were acquired with PMMA blocks for target DAKs ranging from 6.25 to 1600 µGy. Both methods were explored for the effects of data weighting and squared fit coefficients during the curve fitting, the influence of the additional filter material (2 mm Al versus 40 mm PMMA) and noise de-trending. Finally, spatial stationarity of noise was assessed.Data weighting improved noise model fitting over large DAK ranges, especially at low detector exposures. The polynomial and explicit decompositions generally agreed for quantum and electronic noise but FP noise fraction was consistently underestimated by the polynomial method. Noise decomposition as a function of position in the image showed limited noise stationarity, especially for FP noise; thus the position of the region of interest (ROI) used for noise decomposition may influence fractional noise composition. The ROI area and position used in the Guidelines offer an acceptable estimation of noise components. While there are limitations to the polynomial model, when used with care and with appropriate data weighting, the method offers a simple and robust means of examining the detector noise components as a function of detector exposure.

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Background: To evaluate outcomes after optimized laser in situ keratomileusis (LASIK) for astigmatism correction with flap created by a mechanical microkeratome or a femtosecond laser. Patients and Methods: In this retrospective study, a total of 102 eyes of 71 consecutive patients were enrolled undergoing optimized LASIK treatments using the Allegretto laser system (WaveLight Laser Technologie AG, Erlangen, Germany). A mechanical microkeratome for flap creation was used (One Use, Moria®) in 46 eyes (31 patients, spherical equivalent [SE] -4.44 D ± 2.4) and a femtosecond laser was used (LDV, Ziemer®) in 56 eyes (40 patients, spherical equivalent [SE] -3.07 D ± 3.3). The two groups were matched for inclusion criteria and were operated under similar conditions by the same surgeon. Results: Overall, the preoperative spherical equivalent was -9.5 diopters (D) to +3.37 D; the preoperative manifest astigmatism was between -1.5 D and -3.5 D. At 6 months postoperatively, the mean postoperative uncorrected distance visual acuity (UDVA) was 0.93 ± 0.17 (range 0.4 to 1.2) in the Moria group and 1.0 ± 0.21 (range 0.6 to 1.6) in the Femto group, which was statistically significant (p = 0.003). Comparing the cylinder power there was a statistical difference between the two groups (p = 0.0015). Conclusions: This study shows that the method of flap creation has a significant impact on postoperative astigmatism with a significantly better postoperative UDVA in the Femto group. These findings suggest that the femtosecond laser provides a better platform for LASIK treatment of astigmatism than the commonly used microkeratome.

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Background During gait, the hip flexors generate 40% of the total power. Nevertheless, no device has been tested extensively for clinical purposes to cope with weakness in the hip flexors in patients with stroke. Objective The purpose of this study was to assess the efficacy and safety of a newly developed hip flexion assist orthosis in adult patients with hemiparesis after stroke. Design The study used a prospective, randomized, before-after trial design. The inclusion criteria were hemiparesis resulting from stroke (onset ≥8 weeks); ability to walk, even if with assistance; and hip flexion weakness (Medical Research Council Scale score ≤4).¦METHODS: /b> The main outcome measures were the 10-Meter Walk Test and the Six-Minute Walk Test. Patients also were evaluated with the Trunk Control Test, the Functional Ambulation Categories, the Motricity Index, and hip flexor strength on the Medical Research Council Scale. Sixty-two survivors of stroke were tested in random order with and without the orthosis. Any adverse event associated with its use was recorded.¦RESULTS: /b> Both the Six-Minute Walk Test and the 10-Meter Walk Test scores improved with the use of the orthosis. A significant negative correlation was found for improvement between scores on the 2 main outcome measures with the orthosis and the Functional Ambulation Categories scores. The improvement in Six-Minute Walk Test scores with the orthosis was related inversely to hip flexor strength.¦CONCLUSIONS: /b> The data showed that the use of a hip flexion assist orthosis can improve gait in patients with poststroke hemiparesis, particularly those with more severe walking impairment.

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OBJECTIVES: To investigate whether associations of smoking with depression and anxiety are likely to be causal, using a Mendelian randomisation approach. DESIGN: Mendelian randomisation meta-analyses using a genetic variant (rs16969968/rs1051730) as a proxy for smoking heaviness, and observational meta-analyses of the associations of smoking status and smoking heaviness with depression, anxiety and psychological distress. PARTICIPANTS: Current, former and never smokers of European ancestry aged ≥16 years from 25 studies in the Consortium for Causal Analysis Research in Tobacco and Alcohol (CARTA). PRIMARY OUTCOME MEASURES: Binary definitions of depression, anxiety and psychological distress assessed by clinical interview, symptom scales or self-reported recall of clinician diagnosis. RESULTS: The analytic sample included up to 58 176 never smokers, 37 428 former smokers and 32 028 current smokers (total N=127 632). In observational analyses, current smokers had 1.85 times greater odds of depression (95% CI 1.65 to 2.07), 1.71 times greater odds of anxiety (95% CI 1.54 to 1.90) and 1.69 times greater odds of psychological distress (95% CI 1.56 to 1.83) than never smokers. Former smokers also had greater odds of depression, anxiety and psychological distress than never smokers. There was evidence for positive associations of smoking heaviness with depression, anxiety and psychological distress (ORs per cigarette per day: 1.03 (95% CI 1.02 to 1.04), 1.03 (95% CI 1.02 to 1.04) and 1.02 (95% CI 1.02 to 1.03) respectively). In Mendelian randomisation analyses, there was no strong evidence that the minor allele of rs16969968/rs1051730 was associated with depression (OR=1.00, 95% CI 0.95 to 1.05), anxiety (OR=1.02, 95% CI 0.97 to 1.07) or psychological distress (OR=1.02, 95% CI 0.98 to 1.06) in current smokers. Results were similar for former smokers. CONCLUSIONS: Findings from Mendelian randomisation analyses do not support a causal role of smoking heaviness in the development of depression and anxiety.

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Analysis of variance is commonly used in morphometry in order to ascertain differences in parameters between several populations. Failure to detect significant differences between populations (type II error) may be due to suboptimal sampling and lead to erroneous conclusions; the concept of statistical power allows one to avoid such failures by means of an adequate sampling. Several examples are given in the morphometry of the nervous system, showing the use of the power of a hierarchical analysis of variance test for the choice of appropriate sample and subsample sizes. In the first case chosen, neuronal densities in the human visual cortex, we find the number of observations to be of little effect. For dendritic spine densities in the visual cortex of mice and humans, the effect is somewhat larger. A substantial effect is shown in our last example, dendritic segmental lengths in monkey lateral geniculate nucleus. It is in the nature of the hierarchical model that sample size is always more important than subsample size. The relative weight to be attributed to subsample size thus depends on the relative magnitude of the between observations variance compared to the between individuals variance.

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Els objectius d'aquest informe són realitzar un estudi de la tècnica en la digitalització, l'emmagatzematge i l'accés a les tesis doctorals electròniques, per tal de fer una proposta d’organització al Consorci de Biblioteques Universitàries de Catalunya (CBUC). Actualment, tot i que existeixen diverses iniciatives a Europa, és als EUA on la digitalització de tesis doctorals s’ha desenvolupat més amb la creació de la Networked Digital Library for Theses and Dissertation (NDLTD), i ha estat qui ha definit els estàndards en aquest camp. En el següent informe es planteja i es recomana al CBUC l’adhesió institucional a l’NDLTD per poder gaudir de la seva experiència.

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BACKGROUND: Obesity is associated with vitamin D deficiency, and both are areas of active public health concern. We explored the causality and direction of the relationship between body mass index (BMI) and 25-hydroxyvitamin D [25(OH)D] using genetic markers as instrumental variables (IVs) in bi-directional Mendelian randomization (MR) analysis. METHODS AND FINDINGS: We used information from 21 adult cohorts (up to 42,024 participants) with 12 BMI-related SNPs (combined in an allelic score) to produce an instrument for BMI and four SNPs associated with 25(OH)D (combined in two allelic scores, separately for genes encoding its synthesis or metabolism) as an instrument for vitamin D. Regression estimates for the IVs (allele scores) were generated within-study and pooled by meta-analysis to generate summary effects. Associations between vitamin D scores and BMI were confirmed in the Genetic Investigation of Anthropometric Traits (GIANT) consortium (n = 123,864). Each 1 kg/m(2) higher BMI was associated with 1.15% lower 25(OH)D (p = 6.52×10⁻²⁷). The BMI allele score was associated both with BMI (p = 6.30×10⁻⁶²) and 25(OH)D (-0.06% [95% CI -0.10 to -0.02], p = 0.004) in the cohorts that underwent meta-analysis. The two vitamin D allele scores were strongly associated with 25(OH)D (p≤8.07×10⁻⁵⁷ for both scores) but not with BMI (synthesis score, p = 0.88; metabolism score, p = 0.08) in the meta-analysis. A 10% higher genetically instrumented BMI was associated with 4.2% lower 25(OH)D concentrations (IV ratio: -4.2 [95% CI -7.1 to -1.3], p = 0.005). No association was seen for genetically instrumented 25(OH)D with BMI, a finding that was confirmed using data from the GIANT consortium (p≥0.57 for both vitamin D scores). CONCLUSIONS: On the basis of a bi-directional genetic approach that limits confounding, our study suggests that a higher BMI leads to lower 25(OH)D, while any effects of lower 25(OH)D increasing BMI are likely to be small. Population level interventions to reduce BMI are expected to decrease the prevalence of vitamin D deficiency.

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Background: Acute Myeloid Leukemia (AML) in the elderly is notoriously difficult to treat and has a low remission rate with very few long term survivors when using standard treatment approaches. Azacytidine, a hypomethylating agent, has been shown to induce remission and prolong survival in patients with myelodysplastic syndromes; studying this approach to patients with AML is therefore warranted. We present results of an ongoing phase II trial treating elderly or frail AML patients with Azacytidine. Methods: AML elderly or frail patients, and therefore unfit for an intensive chemotherapy regimens, with a WHO performance status 3 were considered for this trial. Trial therapy consisted of 100mg/m2 of Azacytidine injected subcutaneously on 5 consecutive days every 28 days up to 6 cycles, stopping at 6 months if no hematological improvement achieved, or earlier in the case of progression or complications. Treatment was continued beyond 6 months in responding patients. Trial therapy was considered uninteresting if the response rate (CR + PR) within 6 months of therapy initiation was 15% or less and promising if 34% or more. Using the exact single-stage phase II design by A'Hern with a 5% significance level and 90% power, 43 patients were required: If 10 or fewer achieved a response within 6 months the trial therapy should not be considered for further investigation in its current format for this indication and patient population. Results: Between September 2008 and January 2010, 45 evaluable patients across 10 Swiss centers were accrued with a median follow-up of 7 months (range: 0 - 13). 27 (60%) were male, median age was 74 (range: 55 - 86) years and 35 (78.8%) had performance status 0-1. Patients had been excluded from more intensive chemotherapy regimens because of age (n = 37) or due to comorbidities or patient refusal (n=8). Five patients had therapy related AML. Patients received a median of 3 (range: 1 - 10) cycles. Treatment was stopped for not achieving a response by the 6th cycle in 2 patients and earlier in 26 patients (for disease progression in 5, toxicity in 3, patient refusal in 2, recurrent infections in 1, and death in 8). Seventeen patients remain on therapy. The median time spent in the hospital was 12 days (1 - 30) in 24/38 patients hospitalized during the first treatment cycle and 13 days (2 - 28) in 15/31 patients hospitalized during subsequent cycles. Adverse events of grade III or higher most frequently reported were constitutional or hematologic, i.e. fatigue in 5, febrile neutropenia in 8, infections in 6, dyspnea in 6, anemia in 3, neutropenia in 12 and thrombocytopenia in 10, hemorrhage in 2 and retinal detachment in 5. Based on available data on 38 patients, CR/CRi or hematologic improvement or stable disease within 6 months of trial registration was observed in a proportion of patients. Final and mature data, determining whether the predefined proportion of responding patients has been reached or not, will be presented at the conference. Up to now there were a total of 26 deaths. Median overall survival time was 5.7 months (95% CI: 3.1, 8.7). Conclusions: The current results of this slightly modified Azacytidine schedule demonstrate a feasible new therapy option for elderly or frail AML patients in an outpatient setting with moderate, mainly hematologic toxicity.

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Although age-dependent effects on blood pressure (BP) have been reported, they have not been systematically investigated in large-scale genome-wide association studies (GWASs). We leveraged the infrastructure of three well-established consortia (CHARGE, GBPgen, and ICBP) and a nonstandard approach (age stratification and metaregression) to conduct a genome-wide search of common variants with age-dependent effects on systolic (SBP), diastolic (DBP), mean arterial (MAP), and pulse (PP) pressure. In a two-staged design using 99,241 individuals of European ancestry, we identified 20 genome-wide significant (p ≤ 5 × 10(-8)) loci by using joint tests of the SNP main effect and SNP-age interaction. Nine of the significant loci demonstrated nominal evidence of age-dependent effects on BP by tests of the interactions alone. Index SNPs in the EHBP1L1 (DBP and MAP), CASZ1 (SBP and MAP), and GOSR2 (PP) loci exhibited the largest age interactions, with opposite directions of effect in the young versus the old. The changes in the genetic effects over time were small but nonnegligible (up to 1.58 mm Hg over 60 years). The EHBP1L1 locus was discovered through gene-age interactions only in whites but had DBP main effects replicated (p = 8.3 × 10(-4)) in 8,682 Asians from Singapore, indicating potential interethnic heterogeneity. A secondary analysis revealed 22 loci with evidence of age-specific effects (e.g., only in 20 to 29-year-olds). Age can be used to select samples with larger genetic effect sizes and more homogenous phenotypes, which may increase statistical power. Age-dependent effects identified through novel statistical approaches can provide insight into the biology and temporal regulation underlying BP associations.

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STUDY OBJECTIVES: Besides their well-established role in circadian rhythms, our findings that the forebrain expression of the clock-genes Per2 and Dbp increases and decreases, respectively, in relation to time spent awake suggest they also play a role in the homeostatic aspect of sleep regulation. Here, we determined whether time of day modulates the effects of elevated sleep pressure on clock-gene expression. Time of day effects were assessed also for recognized electrophysiological (EEG delta power) and molecular (Homer1a) markers of sleep homeostasis. DESIGN: EEG and qPCR data were obtained for baseline and recovery from 6-h sleep deprivation starting at ZT0, -6, -12, or -18. SETTING: Mouse sleep laboratory. PARTICIPANTS: Male mice. INTERVENTIONS: Sleep deprivation. RESULTS: The sleep-deprivation induced changes in Per2 and Dbp expression importantly varied with time of day, such that Per2 could even decrease during sleep deprivations occurring at the decreasing phase in baseline. Dbp showed similar, albeit opposite dynamics. These unexpected results could be reliably predicted assuming that these transcripts behave according to a driven damped harmonic oscillator. As expected, the sleep-wake distribution accounted for a large degree of the changes in EEG delta power and Homer1a. Nevertheless, the sleep deprivation-induced increase in delta power varied also with time of day with higher than expected levels when recovery sleep started at dark onset. CONCLUSIONS: Per2 and delta power are widely used as exclusive state variables of the circadian and homeostatic process, respectively. Our findings demonstrate a considerable cross-talk between these two processes. As Per2 in the brain responds to both sleep loss and time of day, this molecule is well positioned to keep track of and to anticipate homeostatic sleep need. CITATION: Curie T; Mongrain V; Dorsaz S; Mang GM; Emmenegger Y; Franken P. Homeostatic and circadian contribution to EEG and molecular state variables of sleep regulation. SLEEP 2013;36(3):311-323.

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This study aimed to characterise both the [Formula: see text] kinetics within constant heavy-intensity swimming exercise, and to assess the relationships between [Formula: see text] kinetics and other parameters of aerobic fitness, in well-trained swimmers. On separate days, 21 male swimmers completed: (1) an incremental swimming test to determine their maximal oxygen uptake [Formula: see text], first ventilatory threshold (VT), and the velocity associated with [Formula: see text] [Formula: see text] and (2) two square-wave transitions from rest to heavy-intensity exercise, to determine their [Formula: see text] kinetics. All the tests involved breath-by-breath analysis of freestyle swimming using a swimming snorkel. [Formula: see text] kinetics was modelled with two exponential functions. The mean values for the incremental test were 56.0 ± 6.0 ml min(-1) kg(-1), 1.45 ± 0.08 m s(-1); and 42.1 ± 5.7 ml min(-1) kg(-1) for [Formula: see text], [Formula: see text] and VT, respectively. For the square-wave transition, the time constant of the primary phase (τ(p)) averaged 17.3 ± 5.4 s and the relevant slow component (A'(sc)) averaged 4.8 ± 2.9 ml min(-1) kg(-1) [representing 8.9% of the end-exercise [Formula: see text] (%A'(sc))]. τ(p) was correlated with [Formula: see text] (r = -0.55, P = 0.01), but not with either [Formula: see text] (r = 0.05, ns) or VT (r = 0.14, ns). The %A'(sc) did not correlate with either [Formula: see text] (r = -0.14, ns) or [Formula: see text] (r = 0.06, ns), but was inversely related with VT (r = -0.61, P < 0.01). This study was the first to describe the [Formula: see text] kinetics in heavy-intensity swimming using specific swimming exercise and appropriate methods. As has been demonstrated in cycling, faster [Formula: see text] kinetics allow higher aerobic power outputs to be attained. The slow component seems to be reduced in swimmers with higher ventilatory thresholds.