The stacked thin films have recently been of great interest for enhancing the optical and thermal absorption of the system via their specific optical properties depending on the optical wavelength ...and layer thickness. Here, by using Maxwell’s equation for the electromagnetic fields penetrating thin films, we simulated in detail the absorption of the nanometer-thick thin film of several materials, such as Au, Ag, Cu, and Al, and figured out the optimal thickness range for the outer layers exposed to incoming field to optimize the energy harvesting. In particular, the absorption of the film supported by a totally reflective layer at the back of the structure could be significantly enhanced, and the maximal absorption happens at a layer much thinner than that in the case of the film solely irradiated by the field. These results could help suitably choosing of detailed thickness for the structure to optimize the field effect on a specific layer.
Global myocardial work (GMW) is an emerging method to characterize left ventricle (LV) function with potential advantages over both ejection fraction and global longitudinal strain (GLS). We aimed to ...determine the feasibility and reproducibility for echocardiographic-derived GMW in a healthy pediatric population; establish normal reference values; and investigate the influence of age, gender, and other clinical factor on normal reference ranges. We prospectively enrolled 212 individuals (median age of 9 years; interquartile range, 6 to 12 years, 112 female). Global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE) were measured from LV pressure–strain loops. Quantification of GMW was performed using a GE Vivid E95 system and available software package (Echopac V.203, GE). The mean LV EF was 64 ± 3% with GLS of -21.3 ± 1.5%. GWI was 1688 ± 219 mmHg% with mean GWE of 96.5 ± 1.4%. The GCW was 1959 ± 207 mmHg%, and the mean GWW of 61.1 ± 30.9 mmHg%. No significant difference was found in MW indices across age group and gender (
p
> 0.05 for all). There were significant correlations between both GWI and GCW with GLS and systolic blood pressure (
p
< 0.001), but not with GWE and GWW. Linear regression model revealed that GWI and GCW were more closely correlated with systolic blood pressure than GLS. LV MW indices had good intra-observer and inter-observer reproducibility. This study establishes both the feasibility and reference ranges for non-invasive echocardiographic indices of GMW in healthy children. Myocardial work appears to be a complementary modality to assess LV performance in children.
We aimed to evaluate the microbiological characteristics and risk factors for mortality of infective endocarditis in two tertiary hospitals in Ho Chi Minh City, south Vietnam.
A retrospective study ...of 189 patients (120 men, 69 women; mean age 38 ± 18 years) with the diagnosis of probable or definite infective endocarditis (IE) according to the modified Duke Criteria admitted to The Heart Institute or Tam Duc Hospital between January 2005 and December 2014.
IE was related to a native valve in 165 patients (87.3%), and prosthetic valve in 24 (12.7%). Of the 189 patients in our series, the culture positive rate was 70.4%. The most common isolated pathogens were Streptococci (75.2%), Staphylococci (9.8%) followed by gram negative organism (4.5%). The sensitivity rate of Streptococci to ampicillin, ceftriaxone or vancomycin was 100%. The rate of methicillin resistant Staphylococcus aureus was 40%. There was a decrease in penicillin sensitivity for Streptococci over three eras: 2005-2007 (100%), 2008-2010 (94%) and 2010-2014 (84%). The in-hospital mortality rate was 6.9%. Logistic regression analysis found prosthetic valve and NYHA grade 3 or 4 heart failure and vegetation size of more than 15 mm as strong predictors of in-hospital mortality.
Streptococcal species were the major pathogen of IE in the recent years with low rates of antimicrobial resistance. Prosthetic valve involvement, moderate or severe heart failure and vegetation size of more than 15 mm were independent predictors for in-hospital mortality in IE.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A characteristic equation for the frequencies of the T‐shaped and overhang‐shaped cantilevers is derived for the first time. We show that there are optimum values of the overhang lengths and widths ...that maximize the frequency and the number of maxima is corresponding to the mode number. The frequency of higher‐order modes could be tuned by changing the overhang dimensions. Especially, a semi‐empirical formula for the coupling strength κ between cantilevers in an array is proposed where the strength presents a cubic decrease with the overhang width ξ and a linear increase with the overhang length η, κ=η/ξ3. There is a very good agreement between the proposed formula and the values obtained in recent experiments by other researchers.
Semi‐empirical coupling strength between two cantilevers (lines) and experimental values (symbols).
There is a growing body of literature supporting the utilization of machine learning (ML) to improve diagnosis and prognosis tools of cardiovascular disease. The current study was to investigate the ...impact that the ML framework may have on the sensitivity of predicting the presence or absence of congenital heart disease (CHD) using fetal echocardiography. A comprehensive fetal echocardiogram including 2D cardiac chamber quantification, valvar assessments, assessment of great vessel morphology, and Doppler-derived blood flow interrogation was recorded. The postnatal echocardiogram was used to ascertain the diagnosis of CHD. A random forest (RF) algorithm with a nested tenfold cross-validation was used to train models for assessing the presence of CHD. The study population was derived from a database of 3910 singleton fetuses with maternal age of 28.8 ± 5.2 years and gestational age at the time of fetal echocardiography of 22.0 weeks (IQR 21–24). The proportion of CHD was 14.1% for the studied cohort confirmed by post-natal echocardiograms. Our proposed RF-based framework provided a sensitivity of 0.85, a specificity of 0.88, a positive predictive value of 0.55 and a negative predictive value of 0.97 to detect the CHD with the mean of mean ROC curves of 0.94 and the mean of mean PR curves of 0.84. Additionally, six first features, including cardiac axis, peak velocity of blood flow across the pulmonic valve, cardiothoracic ratio, pulmonary valvar annulus diameter, right ventricular end-diastolic diameter, and aortic valvar annulus diameter, are essential features that play crucial roles in adding more predictive values to the model in detecting patients with CHD. ML using RF can provide increased sensitivity in prenatal CHD screening with very good performance. The incorporation of ML algorithms into fetal echocardiography may further standardize the assessment for CHD.
Squeezed light is a useful phenomenon that can be exploited to improve the sensitivity of specific classes of detectors based on optomechanical effects. In this study, the effect of squeezed light ...was evaluated by explicitly examining the role of the squeezing parameters on the final effective temperature of the oscillator. The results show that the observed cooling and heating effects are strongly dependent on the squeezing parameters and the phase. Using an oscillator of
10.1 MHz driven by a 1064-nm laser, the lowest effective temperature and quantum number are three orders of magnitude smaller compared to the case of no squeezing; especially, these minimum values are obtained at the squeezing phase of about 0.8π. This study highlighted important insights for the optimization of cooling efficiency using squeezed light.
In this work, the entropy functions of ideal quantum gases in a three-dimensional harmonic trap are analytically calculated using temperature as an explicit variable. Afterward, the applicability of ...the analytical formulas is validated by comparison with the numerical calculation. The results illustrate that the obtained functions could be applied for the whole temperature regime with a maximum relative deviation of less than 7.5% in the vicinity of the critical temperature Tc in the case of Bose gases. Meanwhile, for Fermi gases, although the analytical formula fits well at very low- and high-temperature regimes, it cannot be applied at temperature in the range 0.3 - 0.5 T F , where TF is the Fermi temperature. In addition, the consistency between our formulas and classical ones at significantly high temperatures is also discussed.
Mitral valve prolapse (MVP) is the most common valvar dysfunction in children. There is emerging evidence that MVP is not always a benign entity, hence identification of underlying mechanisms is ...pertinent to clinical management. Our group previously identified a ventricular contraction abnormality named end-systolic basal eversion (ESBE) in adults that contributed to MVP. The aim of this study was to evaluate regional circumferential strain in pediatric patients with MVP and ESBE compared to normal controls. Left ventricular circumferential strain was assessed in 16 pediatric patients referred for clinical echocardiographic examination with MVP and ESBE (MVP group) and compared to age-gender-matched healthy subjects. ESBE has been previously described as late systolic bileaflet mitral valve prolapse, papillary traction, and concomitant late systolic outward movement of the basal inferior myocardium. The mean age of the MVP group was 13.8 ± 4.6 year and 75% were female. All patients with MVP and controls had qualitatively normal systolic cardiac function. The MVP group had significantly lower regional strain values for 11/16 of the segments including all 6 basal segments. Importantly, the basal inferior (− 17.02 ± 8.32% vs. − 26.10 ± 3.18, p = 0.001) and basal inferolateral (− 19.53 ± 9.76 vs. − 26.10 ± 3.18, p = 0.03) had the lowest strain values compared to the average of all other segments suggesting weaker contraction in the basal inferior segments. Pediatric patients with MVP and ESBE are subject to a similar left ventricular mechanical dysfunction previously described in adults. ESBE was evident by decreased basal circumferential strain values. These findings denoted weaker contraction which is believed to propagate the late systolic outward movement of the basal ventricular myocardium.
In this work, we present a rigorous mathematical scheme for the derivation of the sth-order perturbative corrections to the solution to a one-dimensional harmonic oscillator perturbed by the ...potential Vper(x) = λxα, where α is a positive integer, using the non-degenerate time-independent perturbation theory. To do so, we derive a generalized formula for the integral I=∫−∞+∞xαexp(−x2)Hn(x)Hm(x)dx, where Hn(x) denotes the Hermite polynomial of degree n, using the generating function of orthogonal polynomials. Finally, the analytical results with α = 3 and α = 4 are discussed in detail and compared with the numerical calculations obtained by the Lagrange-mesh method.
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