This paper presents numerical results for a Rotating Detonation (RD) propagating in a layer of combustible mixture, created by injection of gaseous hydrogen and oxygen. 3D Large Eddy Simulations ...(LES) of a reacting flow have been performed in a domain of planar geometry in order to eliminate possible effects of the chamber curvature. First, the results for a 2D case with uniformly distributed premixed injection are presented to characterize the RD propagation under the most idealized conditions. Then a 3D concept is introduced for the injector composed of a series of injection elements. The RD propagation is simulated under the conditions of premixed and separate injection of the propellants at globally stoichiometric proportions. The case of separate propellant injection is the most realistic one. The computational results, represented by instantaneous and averaged flowfields, are analyzed to characterize the flowfield and the conditions of RD propagation. This analysis allows identifying the effects due to two major factors: the injection through discrete holes with respect to the distributed one and the separate propellant feeding with respect to the premixed one. Macroscopic quantities, such as the RD propagation speed, mean chamber pressure, average parameters of the mixture, and mixing efficiency are evaluated and compared in order to characterize the studied effects.
•Rotating detonation propagating in a H2/O2 mixture is simulated by LES.•3D injector is considered for premixed and separate propellant injection.•Simulation results for the established propagation are presented and analyzed.•With separate injection, propellant mixing is limited by the stratification effect.•Quantitative analysis is conducted to estimate the combustion process efficiency.
Background
Sarcopenia is characterized by progressive loss of muscle mass with corresponding decline in strength and/or physical function. The economic burden of sarcopenia-associated disability is ...considerable in the US.
Objective
To estimate the cost of hospitalizations in US adults with sarcopenia categorized by age, sex, and race/ethnicity.
Design, setting and participants
A retrospective, prevalence based, economic burden study, consisting of 4011 adults aged ≥40 years with and without sarcopenia.
Methods
Data on prevalence of low lean mass, functional limitations, and hospitalizations were obtained from the National Health and Nutrition Examination Survey (1999–2004); cost of hospitalizations was obtained from the Healthcare Cost and Utilization Project — National Inpatient Sample (2014), and population estimates were obtained from the US Census (2014). Probability and cost of hospitalizations were estimated by multiple logistic regression and negative binomial regression models, respectively.
Results
The total estimated cost of hospitalizations in individuals with sarcopenia was USD $40.4 billion with an average per person cost of USD $260. Within this category, average per person cost was highest for Hispanic women (USD $548) and lowest for Non-Hispanic Black women (USD $25); average per person cost was higher for older adults (≥65 years) (USD $375) than younger adults (40–64 years) (USD $204) with sarcopenia. The total cost of hospitalizations in individuals with sarcopenia (≥65 years) was USD $19.12 billion. Individuals with sarcopenia had greater odds of hospitalization (OR, 1.95; p<.001) compared to those without and had an annual marginal increase in cost of USD $2315.7 per person compared to individuals without sarcopenia.
Conclusion
Sarcopenia places considerable economic burden on the US healthcare system. The ethnic disparity and economic burden associated with sarcopenia warrant further investigation.
•We propose two simple setups to measure bubble size distributions of foams using the lensing properties of bubbles.•Simple optical modelling captures very well the experimental data.•Image treatment ...of small and large bubbles can hence be fully automated without the need of calibration.
An increasing number of research topics and applications ask for a precise measurement of the size distribution of small bubbles in a liquid—and hence for reliable and automated image analysis. However, due to the strong mismatch between the refractive index of a liquid and a gas, bubbles deform strongly the path of light rays, rendering automated bubble size analysis a challenging task. We show here how this challenge can be met using the fact that bubbles act like inverted, spherical lenses with a curvature which is the inverse of the bubble radius. The imaging properties of each bubble can then be used to accurately determine the radius of the bubble upon imaging an object which can be filtered easily by a computer. When bubbles are large enough to be deformed under the influence of gravity, it is more appropriate to measure their size after squeezing them between two narrowly spaced glass plates. We therefore show here, how the analysis can be extended to this case; and how both approaches can be combined to measure the size distributions of strongly polydisperse foams containing simultaneously small (several 10s of micrometres) and large bubbles (several 100s of micrometres).
The paper presents the methodology and the results of a numerical study, which is aimed at the investigation and optimisation of different means of fuel and oxidizer injection adapted to rocket ...engines operating in the rotating detonation mode. As the simulations are achieved at the local scale of a single injection element, only one periodic pattern of the whole geometry can be calculated so that the travelling detonation waves and the associated chemical reactions can not be taken into account. Here, separate injection of fuel and oxidizer is considered because premixed injection is handicapped by the risk of upstream propagation of the detonation wave. Different associations of geometrical periodicity and symmetry are investigated for the injection elements distributed over the injector head. To analyse the injection and mixing processes, a nonreacting 3D flow is simulated using the LES approach. Performance of the studied configurations is analysed using the results on instantaneous and mean flowfields as well as by comparing the mixing efficiency and the total pressure recovery evaluated for different configurations.
•Injection elements are optimised in non reacting conditions for a detonation engine•LES results are used to compare six different configurations for H2/O2 injection•Injector performance is evaluated with mixing efficiency and total pressure recovery•Optimum mixing is obtained for a combination of shear and impingement of propellants•A correlation between mixing efficiency and total pressure recovery is demonstrated
The treatment of early-stage cervical cancer (CC) is primarily based on surgery. Adjuvant (chemo)radiotherapy can be necessary in presence of risk factors for relapse (tumor size, deep stromal ...invasion, lymphovascular space invasion (LVSI), positive margins, parametrial or lymph node involvement), increasing the risk of treatment toxicity. Preoperative brachytherapy can reduce tumor extension before surgery, potentially limiting the need for adjuvant radiotherapy. This study reports long-term clinical outcomes on efficacy and toxicity of preoperative pulse-dose-rate (PDR) brachytherapy in early-stage CC.
All patients treated at Institut Curie between 2007 and 2022 for early-stage CC by preoperative brachytherapy were included. A PDR technique was used. Patients underwent hysterectomy associated with nodal staging following brachytherapy.
73 patients were included. The median time from brachytherapy to surgery was 45 days range: 25–78 days. With a median follow-up of 51 months range: 4–185, we reported 3 local (4 %), 1 locoregional (1 %) and 8 metastatic (11 %) relapses. At 10 years, OS was 84.1 % 95 % CI: 70.0–100, DFS 84.3 % 95 % CI:74.6–95.3 and LRFS 92.8 % 95 % CI:84.8–100. Persistence of a tumor residue, observed in 32 patients (44 %), was a significant risk factor for metastatic relapse (p = 0.02) and was associated with the largest tumor size before brachytherapy (p = 0.04). Five patients (7 %) experienced grade 3 toxicity. One patient (1 %) developed grade 4 toxicity. Ten patients (14 %) received adjuvant radiotherapy, increasing the risk of lymphedema (HR 1.31, 95 % CI 1.11–1.54; p = 0.002).
PDR preoperative brachytherapy for early-stage cervical cancer provides high long-term tumor control rates with low toxicity.
To compare first-line surgery with first-line assisted reproductive techniques (ART) in infertile women with deep infiltrating endometriosis (DIE) without colorectal involvement.
A retrospective ...comparative cohort study with a propensity-score matching analysis, in four tertiary-care referral centers. The population was infertile women with DIE without colorectal involvement. The patients were managed either by first-line surgery followed by spontaneous conception attempts and/or ART, or by first-line ART. 284 patients were extracted from the databases. After matching, 92 patients were compared in each group. Clinical pregnancy rates (PR) and live-birth rates (LBR) were the primary outcomes, and cumulative pregnancy rate (CPR) and cumulative live birth rate (CLBR) were the secondary outcomes.
The mean number of IVF-ICSI cycles per patient was 1.4, with a significant difference between the groups: 1.6 in the first-line ART group and 1.2 in the first-line surgery group (p = 0.006). The PR was significantly higher in the first-line surgery group (72 % vs 35 %; p < 0.001). In the first-line surgery group, non-ART pregnancies occurred in 18 % (17/92) while no non-ART pregnancies was noted in the first-line ART group. The LBR was significantly higher in the first-line surgery group (61 % vs 24 %; p < 0.001). After ART, the CPR were 72 % (47/67) in the first-line surgery group, and 35 % (32/92) in the first-line ART group (p < 0.001).
After matching, our results support that first-line surgery offer higher pregnancy and live-birth rates than first-line ART in patients with DIE without colorectal involvement.
Enhanced recovery after surgery (ERAS) programs are associated with improved management, reduced hospital stays, and lower complication rates.
To evaluate the impact of ERAS on mean length of stay ...(LOS) and postoperative morbidity in breast reconstruction with latissimus dorsi flap (LDF) compared with conventional recovery program.
All patients operated by LDF between December 2014 and October 2020: those managed before April 2018, when the ERAS protocol was introduced, were included in the "no ERAS” group, and beyond in the "ERAS" group.
Out of 193 patients, 129 were included in the “ERAS” group and 64 in the “no ERAS” group. There was a significant difference between the two groups in LOS (4.2 ± 1.5 days in the “ERAS” group vs. 5.4 ± 1.9 days in the “no ERAS” group; p < 0.001), high-grade complications at 30 days (9.3% in the “ERAS” group vs. 25% in the “no ERAS” group; p = 0.01), reintervention rate (13.9% vs. 26.6%, respectively; p = 0.02), and 30-day rehospitalization rate (6.2% in the “ERAS” group vs. 15.6% in the “no ERAS” group; p = 0.03).
The ERAS protocol has a positive impact on breast reconstruction with LDF without generating additional adverse effects. These results support the democratization of these programs for breast reconstruction surgery.
Problem solving is a key component of authentic scientific research and practice in organic chemistry. One factor that has been shown to have a major role in successful problem solving in a variety ...of disciplines is metacognitive regulation, defined as the control of one's thought processes through the use of planning, monitoring, and evaluation strategies. Despite the growing interest in assessing and promoting metacognition in the field of chemical education, few studies have investigated this topic in the context of organic chemistry students. To gain a deeper understanding of how and why students make use of strategies related to metacognitive regulation in their approaches to solving problems, we conducted interviews with Organic Chemistry I, Organic Chemistry II, and graduate organic chemistry students and used multiple measures to examine students' metacognition. As a part of these interviews, students verbalized their thoughts as they worked on complex predict-the-product problems and completed a self-report instrument indicating which planning, monitoring, and evaluation strategies they had used while completing each problem. Think-aloud protocols were analyzed for the presence of each of the behaviors included on the self-report instrument, and students' use of metacognitive strategies was compared to identify differences between students with different levels of experience and between students who generated more and less successful solutions to the problems. Students who generated more successful solutions to the problems tended to report using a greater number of metacognitive strategies. When asked why they did or did not use certain metacognitive strategies, students indicated a number of factors, such as not feeling able to use these strategies effectively or believing that using these strategies was unnecessary. The results of this study support the importance of teaching metacognitive problem-solving strategies in organic chemistry courses and suggest several methods for the assessment and instruction of metacognition.
DNA structural deformations and dynamics are crucial to its interactions in the cell. Theoretical simulations are essential tools used to explore the structure, dynamics, and thermodynamics of ...biomolecules in a systematic way. Molecular mechanics force fields for DNA have benefited from constant improvements during the past decades. Several studies have evaluated and compared available force fields when the solvent is modeled by explicit molecules. On the other hand, few systematic studies have assessed the quality of duplex DNA models when implicit solvation is employed. The interest in an implicit modeling of the solvent consists of the important gain in simulation performance and conformational sampling speed. In this study, respective influences of the force field and the implicit solvation model choice on DNA simulation quality are evaluated. To this end, extensive implicit solvent duplex DNA simulations are performed, attempting to reach both conformational and sequence diversity convergence. Structural parameters are extracted from simulations and statistically compared to available experimental and explicit solvation simulation data. Our results quantitatively expose the respective strengths and weaknesses of the different DNA force fields and implicit solvation models studied. This work can lead to the suggestion of improvements to current DNA theoretical models.
The prevalence of diabetes among Americans aged 65 years and older is greater than 25%. Medical expenditures for persons with diabetes are more than twice as high as those for patients without ...diabetes. Diabetes in older adults often times coexists with frailty, resulting in reduced quality of life and increased health-care use. Many older adults with type 2 diabetes have mobility impairments and experience falls, which contributes to increased frailty. Exercise has a protective effect for frailty and falls, yet less than half of persons with diabetes exercise and approximately one-quarter meet exercise recommendations. In addition to exercise, nutrition may help reduce the risk for falls; however, nutritional interventions have not been tested as a fall-prevention intervention. According to a review, there is insufficient evidence to create nutritional guidelines specific for frail older adults with type 2 diabetes. There is a need to motivate and empower older adults with type 2 diabetes to make lifestyle changes to prevent frailty. The purpose of this review was to identify and integrate what is known and what still needs to be done for this population to be successful in making health behavior changes to reduce frailty. There is some evidence that motivational approaches have worked for older adults with various chronic disease conditions. However, studies applying motivational strategies are lacking for frail older adults with type 2 diabetes. A novel motivational approach was described; it combines aspects of the Health Belief Model and Motivational Interviewing. Intervention studies incorporating this model are needed to determine whether this client-driven strategy can help various racial/ethnic populations make the sustainable health behavior changes of increasing exercise and healthy eating while taking into consideration physiological, psychological, and economic barriers.
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