Characteristics and outcomes of multisystem inflammatory syndrome in children: A multicenter, retrospective, observational cohort study in Mexico.

Introduction: Multisystem inflammatory syndrome in children associated with coronavirus disease 2019 (MIS-C), a novel hyperinflammatory condition secondary to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, is associated with severe outcomes such as coronary artery aneurysm and death. Methods: This multicenter, retrospective, observational cohort study including eight centers in Mexico, aimed to describe the clinical characteristics and outcomes of patients with MIS-C. Patient data were evaluated using latent class analysis (LCA) to categorize patients into three phenotypes: toxic shock syndrome-like (TSSL)-MIS-C, Kawasaki disease-like (KDL)-MIS-C, and nonspecific MIS-C (NS-MIS-C). Risk factors for adverse outcomes were estimated using multilevel mixed-effects logistic regression. Results: The study included 239 patients with MIS-C, including 61 (26%), 70 (29%), and 108 (45%) patients in the TSSL-MIS-C, KDL-MIS-C, and NS-MIS-C groups, respectively. Fifty-four percent of the patients were admitted to the intensive care unit, and 42%, 78%, and 41% received intravenous immunoglobulin, systemic glucocorticoids, and anticoagulants, respectively. Coronary artery dilatation and aneurysms were found in 5.7% and 13.2% of the patients in whom coronary artery diameter was measured, respectively. Any cause in-hospital mortality was 5.4%. Hospitalization after ten days of symptoms was associated with coronary artery abnormalities (odds ratio [OR] 1.6, 95% confidence interval [CI] 1.2-2.0). Age ≥10 years (OR: 5.6, 95% CI: 1.4-2.04), severe underlying condition (OR: 9.3, 95% CI: 2.8-31.0), platelet count <150,000 /mm3 (OR: 4.2, 95% CI: 1.2-14.7), international normalized ratio >1.2 (OR: 3.8, 95% CI: 1.05-13.9), and serum ferritin concentration >1,500 mg/dl at admission (OR: 52, 95% CI: 5.9-463) were risk factors for death. Discussion: Mortality in patients with MIS-C was higher than reported in other series, probably because of a high rate of cases with serious underlying diseases.

An efficient analysis of oblique reflection of airborne ultrasound beams from thin membranes for gas sensing.

The use of the angular spectrum method (ASM) to simulate the reflection of airborne ultrasound beams from a thin membrane separating air from a mixture of air and another gas is examined. The main advantage of this method is its high computing speed and efficiency for practical design calculations, suitable for sensing applications. The implemented ASM code is validated against custom Rayleigh integral code in a pure propagation simulation. In addition, ultrasound beam reflection calculations using ASM with finite element numerical results and experimental measurements are compared, finding good agreement in both cases. Then, ASM is used to estimate the sensitivity of specular reflection signals to variations in the composition of the incidence medium as a function of the angle of incidence. Conditions for which a reflection signal using inexpensive commercial ultrasound emitter/receiver at 40 kHz, in a simple configuration, offer a high enough sensitivity suitable for monitoring air quality indoors are found.

Default Mode Network Efficiency Is Correlated With Deficits in Inhibition in Adolescents With Inhalant Use Disorder.

It is well established that alterations in cognitive function and damage to brain structures are often found in adolescents who have substance use disorder (SUD). However, deficits in executive cognitive functioning in adolescents related to the vulnerability and consumption of such substances are not well known. In this study, we use graph theoretic analysis to compare the network efficiency in the resting state for three networks-default mode network (DMN), salience network (SN) and fronto-parietal network (FPN)-between inhalant-consuming adolescents and a control group (12 to 17 years old). We analyzed whether the efficiency of these functional networks was related to working memory, mental flexibility, inhibition of response, and sequential planning. We found that, when compared to the control group, inhalant-consuming adolescents presented with important deficits in communication among brain regions that comprise the DMN, SN, and FPN networks. DMN is the most affected network by inhalant abuse during adolescence. The mediation analyses suggested that the relationship between inhalant abuse and inhibitory control and sequential planning was partly mediated by DMN efficiency.

Using Schlieren imaging to estimate the geometry of a shock wave radiated by a trumpet bell.

The Schlieren method has been used before to visualize weak shock waves radiated from the open ends of brass instruments, but no attempt has previously been undertaken, however, to measure the geometry of the radiated wavefronts using the Schlieren images. In this paper Schlieren visualization is used to estimate the geometry of the two-dimensional shock wavefronts radiated from the bell of a trumpet at different frequencies. It is observed that the geometry of the shocks does change with frequency, in the expected manner. The propagation speeds of these shocks are also calculated, and they too exhibit the anticipated behavior.

Evaluation of the bias error of transmission tube measurements of normal-incidence sound transmission loss using narrow tube reference elements.

The bias errors of transmission tube measurements are evaluated using an empty test tube condition, implying full sound transmission, normal-incidence sound transmission loss (nSTL) = 0, and two narrow tube elements presenting a theoretically known sound transmission loss (which includes modeling of thermo-viscous losses), varying in frequency around moderate non-zero nSTL levels, and approaching insulation levels more typically found in applications. Results show that the different reference conditions are virtually equivalent in presenting negligible amounts of bias error within the corresponding measurement uncertainties, typically within ±1 dB, in the full 6000 Hz measurement frequency range in this particular case. Slight differences are evident only in the upper third of this range, from 4000 to 6000 Hz, in which bias errors for the narrow tube elements are found very slightly beyond the measurement uncertainties, suggesting the existence of additional sound loss mechanisms. Measurements of a typical insulating test sample are also presented for illustration of the possible non-significance of bias errors in practical cases.