2,245 research outputs found
Laser-induced thermal acoustics (LITA) signals from finite beams
Laser-induced thermal acoustics (LITA) is a four-wave mixing technique that may be employed to measure sound speeds, transport properties, velocities, and susceptibilities of fluids. It is particularly effective in high-pressure gases (>1 bar). An analytical expression for LITA signals is derived by the use of linearized equations of hydrodynamics and light scattering. This analysis, which includes full finite-beam-size effects and the optoacoustic effects of thermalization and electrostriction, predicts the amplitude and the time history of narrow-band time-resolved LITA and broadband spectrally resolved (multiplex) LITA signals. The time behavior of the detected LITA signal depends significantly on the detection solid angle, with implications for the measurement of diffusivities by the use of LITA and the proper physical picture of LITA scattering. This and other elements of the physics of LITA that emerge from the analysis are discussed. Theoretical signals are compared with experimental LITA data
Predictors of fatigue severity in early systemic sclerosis: a prospective longitudinal study of the GENISOS cohort.
ObjectivesLongitudinal studies examining the baseline predictors of fatigue in SSc have not been reported. Our objectives were to examine the course of fatigue severity over time and to identify baseline clinical, demographic, and psychosocial predictors of sequentially obtained fatigue scores in early SSc. We also examined baseline predictors of change in fatigue severity over time.MethodsWe analyzed 1090 longitudinal Fatigue Severity Scale (FSS) scores belonging to 256 patients who were enrolled in the Genetics versus Environment in Scleroderma Outcomes Study (GENISOS). Predictive significance of baseline variables for sequentially obtained FSS scores was examined with generalized linear mixed models. Predictors of change in FSS over time were examined by adding an interaction term between the baseline variable and time-in-study to the model.ResultsThe patients' mean age was 48.6 years, 47% were Caucasians, and 59% had diffuse cutaneous involvement. The mean disease duration at enrollment was 2.5 years. The FSS was obtained at enrollment and follow-up visits (mean follow-up time = 3.8 years). Average baseline FSS score was 4.7(±0.96). The FSS was relatively stable and did not show a consistent trend for change over time (p = 0.221). In a multivariable model of objective clinical variables, higher Medsger Gastrointestinal (p = 0.006) and Joint (p = 0.024) Severity Indices, and anti-U1-RNP antibodies (p = 0.024) were independent predictors of higher FSS. In the final model, ineffective coping skills captured by higher Illness Behavior Questionnaire scores (p<0.001), higher self-reported pain (p = 0.006), and higher Medsger Gastrointestinal Severity Index (p = 0.009) at enrollment were independent predictors of higher longitudinal FSS scores. Baseline DLco % predicted was the only independent variable that significantly predicted a change in FSS scores over time (p = 0.013), with lower DLco levels predicting an increase in FSS over time.ConclusionsThis study identified potentially modifiable clinical and psychological factors that predict longitudinal fatigue severity in early SSc
Biomimetic Non-Heme Iron-Catalyzed Epoxidation of Challenging Terminal Alkenes Using Aqueous H2O2 as an Environmentally Friendly Oxidant
Catalysis mediated by iron complexes is emerging as an eco-friendly and inexpensive option in comparison to traditional metal catalysis. The epoxidation of alkenes constitutes an attractive application of iron(III) catalysis, in which terminal olefins are challenging substrates. Herein, we describe our study on the design of biomimetic non-heme ligands for the in situ generation of iron(III) complexes and their evaluation as potential catalysts in epoxidation of terminal olefins. Since it is well-known that active sites of oxidases might involve imidazole fragment of histidine, various simple imidazole derivatives (seven compounds) were initially evaluated in order to find the best reaction conditions and to develop, subsequently, more elaborated amino acid-derived peptide-like chiral ligands (10 derivatives) for enantioselective epoxidations
Obesity: Problem to Consider in Public Health
Overweight is an increase in body mass; Obesity is the increase in the size or quantity of fat cells sufficient to damage the health of the individual. It is the world millennium pandemic, which affects all types of population, does not discriminate between age, race, sex, social position or religion, according to the World Health Organization is considered obese to people with a higher body mass index or equal to 30 Kg / m2. It has been shown that through good advice can be remedied with this acute physical problem and that often leads to self-esteem and mental problems. The work is supported in the investigation of the phenomenon of obesity, its causes, and consequences for human health in the parish March 12, in the city of Portoviejo in the province of ManabÃ. The results of a survey carried out on a sample of 97 adults residing in the parish are exposed, showing the high level of obesity that exists in the population, as well as the inadequate eating habits and the sedentary lifestyle that accompanies this problem. Health. It is evident that the fundamental causes of obesity consist of a well-localized group of inadequate food practices and the lack of physical exercise, a situation that can be combated from social work where the factors and the society of the community can be compromised, aimed at reducing obesity levels and increasing the health of the population
Reversible switching of room temperature ferromagnetism in CeO2-Co nanoparticles
We investigated the reversible ferromagnetic (FM) behavior of pure and Co
doped CeO2 nanopowders. The as-sintered samples displayed an increasing
paramagnetic contribution upon Co doping. Room temperature FM is obtained
simply by performing thermal treatments in vacuum at temperatures as low as
500^{\circ}C and it can be switched off by performing thermal treatments in
oxidizing conditions. The FM contribution is enhanced as we increase the time
of the thermal treatment in vacuum. Those systematic experiments establish a
direct relation between ferromagnetism and oxygen vacancies and open a path for
developing materials with tailored properties.Comment: 20 pages, 3 figures; Applied Physics Letters Vol. 100, Issue 17,
APR201
Improved prognosis after cardiac resynchronization therapy over a decade
Aims The past decade has seen an increased delivery of cardiac resynchronization therapy (CRT) for patients with heart failure (HF). We explored whether clinical outcomes after CRT have changed from the perspective of an entire public healthcare system. Methods and results A national database covering the population of England (56.3 million in 2019) was used to explore clinical outcomes after CRT from 2010 to 2019. A total of 64 698 consecutive patients (age 71.4 ± 11.7 years; 74.8% male) underwent CRT-defibrillation [n = 32 313 (49.7%)] or CRT-pacing [n = 32 655 (50.3%)] implantation. From 2010–2011 to 2018–2019, there was a 76% increase in CRT implantations. During the same period, the proportion of patients with hypertension (59.6–73.4%), diabetes (26.5–30.8%), and chronic kidney disease (8.62–22.5%) increased, as did the Charlson comorbidity index (CCI ≥ 3 from 20.0% to 25.1%) (all P < 0.001). Total mortality decreased at 30 days (1.43–1.09%) and 1 year (9.51–8.13%) after implantation (both P < 0.001). At 2 years, total mortality [hazard ratio (HR): 0.72; 95% confidence interval (CI) 0.69–0.76] and total mortality or HF hospitalization (HR: 0.59; 95% CI 0.57–0.62) decreased from 2010–2011 to 2018–2019, after correction for age, race, sex, device type (CRT-defibrillation or pacing), comorbidities (hypertension, diabetes, chronic kidney disease, and myocardial infarction), or the CCI (HR: 0.81; 95% CI 0.77–0.85). Conclusions From the perspective of an entire public health system, survival has improved and HF hospitalizations have decreased after CRT implantation over the past decade. This prognostic improvement has occurred despite an increasing comorbidity burden
Time resolved pattern evolution in a large aperture laser
We have measured quasi-instantaneous transverse patterns in a broad aperture
laser. Non-ordered patterns yielding to boundary determined regular structures
in progressive time-integrated recording are observed. The linear analysis and
numerical integration of the full Maxwell-Bloch equations allow us to interpret
the features of the experiment. We show that this system being far from
threshold cannot be fully understood with a perturbative model.Comment: 7 pages, 5 GIF figures . To be published in Phys. Rev. Let
Timing of cardiac resynchronization therapy implantation
Aims The optimum timing of cardiac resynchronization therapy (CRT) implantation is unknown. We explored long-term outcomes after CRT in relation to the time interval from a first heart failure hospitalization (HFH) to device implantation. .Methods A database covering the population of England (56.3 million in 2019) was used to quantify clinical outcomes after CRT im- and results plantation in relation to first HFHs. From 2010 to 2019, 64 968 patients [age: 71.4 ± 11.7 years; 48 606 (74.8%) male] underwent CRT implantation, 57% in the absence of a previous HFH, 12.9% during the first HFH, and 30.1% after ≥1 HFH. Over 4.54 (2.80–6.71) years [median (interquartile range); 272 989 person-years], the time in years from the first HFH to CRT implantation was associated with a higher risk of total mortality [hazard ratio (HR); 95% confidence intervals (95% CI)] (1.15; 95% CI 1.14–1.16, HFH (HR: 1.26; 95% CI 1.24–1.28), and the combined endpoint of total mortality or HFH (HR: 1.19; 95% CI 1.27–1.20) than CRT in patients with no previous HFHs, after co-variate adjustment. Total mortality (HR: 1.67), HFH (HR: 2.63), and total mortality or HFH (HR: 1.92) (all P < 0.001) were highest in patients undergoing CRT ≥2 years after the first HFH. Conclusion In this study of a healthcare system covering an entire nation, delays from a first HFH to CRT implantation were associated with progressively worse long-term clinical outcomes. The best clinical outcomes were observed in patients with no previous HFH and in those undergoing CRT implantation during the first HFH. Condensed The optimum timing of CRT implantation is unknown. In this study of 64 968 consecutive patients, delays from a first heart abstract failure hospitalization (HFH) to CRT implantation were associated with progressively worse long-term clinical outcomes. Each year from a first HFH to CRT implantation was associated with a 21% higher risk of total mortality and a 34% higher risk of HFH. The best outcomes after CRT were observed in patients with no previous HFHs and in those undergoing implantation during their first HFH. The left upper panel shows the timing (y-axis) and numbers (x-axis) of cardiac resynchronization therapy (CRT) implantations in relation to the timing of first heart failure hospitalizations (HFHs); the right upper panel shows CRT implantations undertaken during a first HFH as a percentage of all implantations, according to year. Patients were regarded as not having had a HFH if this had not occurred within 5 years prior to CRT implantation. The left lower panel shows the Kaplan–Meier survival curve for total mortality. Event rates (per 100 person-years) for the three endpoints according to the timing of CRT implantation in relation to a first HFH are shown in the right lower panel
- …