Force and torque model sensitivity and coarse graining for bedload-dominated sediment transport

We present results from Euler–Lagrange simulations of turbulent flow over an erodible monodisperse bed of particles at a shear Reynolds number of R e τ = 180 . The Galileo number G a and the ratio of Shields to the critical Shields number Θ / θ c r were varied in the range 11.4 to 29.8 and 1.32 to 5.98, respectively. Two drag force models were investigated along with the influence of lift, particle rotation, and tangential collision forces for each model. Both models give similar results as far as mean particle flux and Shields stress are concerned, however we find that excluding particle rotation, without ignoring the associated tangential collisional force, significantly reduces the particle flux with little influence on Shields stress. On the other hand, when both particle rotation and tangential collision forces are not taken into account, the particle flux is practically unchanged, but the excess Shields stress slightly increases compared to the case where both effects are considered. We also find the lift force to substantially influence particle flux. Additionally, we show the importance of spatial coarse graining and time averaging for Euler–Euler simulations and quantify the reduction in scatter for space and time dependent variables such as sediment flux, Shields stress, and bed surface fluid velocities

The role of bed-penetrating Kelvin–Helmholtz vortices on local and instantaneous bedload sediment transport

We present results from open-channel, Euler–Lagrange (EL) simulations of turbulent flow over an erodible particle bed at a shear Reynolds number of Reτ=180 . Upon space and time averaging, our simulations correctly reproduce the Wong & Parker (ASCE J. Hydraul. Engng, vol. 132, issue 11, 2006, pp. 1159–1168) bedload transport relation (WP). However, local and instantaneous sediment flux shows orders of magnitude scatter around the WP prediction. Visualization of the vortical structures using swirling strength shows the existence of bed-penetrating Kelvin–Helmholtz (KH) vortex packets, which coupled with particle inertia are primarily responsible for the large scatter. The results also show that Euler–Euler (EE) simulations, where the individual sediment grains are not distinguished, are still able to reliably capture the turbulent shear stress variation, however, they do not capture the wide distribution of sediment flux indicative of saltating transport. The KH vortices induce non-zero streamwise and bed-normal velocities at the upper surface of the bed, which must be considered in EE simulations

One-stop stroke management platform reduces workflow times in patients receiving mechanical thrombectomy

Background and purposeClinical outcome in patients who received thrombectomy treatment is time-dependent. The purpose of this study was to evaluate the efficacy of the one-stop stroke management (OSSM) platform in reducing in-hospital workflow times in patients receiving thrombectomy compared with the traditional model.MethodsThe data of patients who received thrombectomy treatment through the OSSM platform and traditional protocol transshipment pathway were retrospectively analyzed and compared. The treatment-related time interval and the clinical outcome of the two groups were also assessed and compared. The primary efficacy endpoint was the time from door to groin puncture (DPT).ResultsThere were 196 patients in the OSSM group and 210 patients in the control group, in which they were treated by the traditional approach. The mean DPT was significantly shorter in the OSSM group than in the control group (76 vs. 122 min; P < 0.001). The percentages of good clinical outcomes at the 90-day time point of the two groups were comparable (P = 0.110). A total of 121 patients in the OSSM group and 124 patients in the control group arrived at the hospital within 360 min from symptom onset. The mean DPT and time from symptom onset to recanalization (ORT) were significantly shorter in the OSSM group than in the control group. Finally, a higher rate of good functional outcomes was achieved in the OSSM group than in the control group (53.71 vs. 40.32%; P = 0.036).ConclusionCompared to the traditional transfer model, the OSSM transfer model significantly reduced the in-hospital delay in patients with acute stroke receiving thrombectomy treatment. This novel model significantly improved the clinical outcomes of patients presenting within the first 6 h after symptom onset

Postoperative Fever: The Potential Relationship with Prognosis in Node Negative Breast Cancer Patients

Background: Postoperative fever may serve as an indirect sign to reflect the alterations of the host milieu caused by surgery. It still remains open to investigation whether postoperative fever has a bearing on prognosis in patients with lymph node negative breast cancers. Methods: We performed a retrospective study of 883 female unilateral patients with lymph node negative breast cancer. Fever was defined as an oral temperature $38 in one week postoperation. Survival curves were performed with Kaplan-Meier method, and annual relapse hazard was estimated by hazard function. Findings: The fever patients were older than those without fever (P,0.0001). Hypertensive patients had a propensity for fever after surgery (P = 0.011). A statistically significant difference was yielded in the incidence of fever among HR+/ERBB2-, ERBB2+, HR-/ERBB2- subgroups (P = 0.012). In the univariate survival analysis, we observed postoperative fever patients were more likely to recur than those without fever (P = 0.0027). The Cox proportional hazards regression analysis showed that postoperative fever (P = 0.044, RR = 1.89, 95%CI 1.02–3.52) as well as the HR/ERBB2 subgroups (P = 0.013, HR = 1.60, 95%CI 1.09–2.31) was an independent prognostic factor for relapse-free survival. Conclusion: Postoperative fever may contribute to relapse in node negative breast cancer patients, which suggests that changes in host milieu related to fever might accelerate the growth of micro-metastatic foci. It may be more precise t

Acetic acid activates the AMP-activated protein kinase signaling pathway to regulate lipid metabolism in bovine hepatocytes.

<p>Acetic acid is metabolized to acetyl-CoA with consumption of ATP in bovine hepatocytes, resulting in a significant elevation of the AMP/ATP ratio and the phosphorylation and activation of AMPKα. Activated AMPKα increases the expression and transcriptional activity of PPARα, thereby increasing the expression of lipolytic genes, including ACO, CPT1, CPT2, and L-FABP. AMPKα activation inhibits the expression and transcriptional activity of SREBP-1c and ChREBP, thereby reducing the expression of lipogenic genes, including ACC1, FAS, and SCD-1. In addition, activated AMPKα directly phosphorylates and inhibits ACC1. Consequently, acetic acid increases lipolysis and reduces lipid synthesis in bovine hepatocytes.</p

The mRNA and protein expression levels of PPARα, SREBP-1c, and ChREBP in the hepatocytes.

<p>Hepatocytes were treated with acetate and BML-275 and divided into a control group (0 mM acetate), a low-dose acetate treatment group (1.8 mM acetate), a medium-dose acetate treatment group (3.6 mM acetate), a high-dose acetate treatment group (7.2 mM acetate), a BML-275 group (10 μM BML-275), and a BML-275+acetate group (10 μM BML-275+3.6 mM acetate). Acetate (sodium acetate) was used in the form of neutralized acetic acid to avoid changing the pH of the medium. A: Western blotting results of PPARα, SREBP-1c, and ChREBP. B and C: mRNA and protein levels of PPARα. D and E: mRNA and protein levels of SREBP-1c. F and G: mRNA and protein levels of ChREBP. * <i>p</i><0.05, ** <i>p</i><0.01 versus the control group.</p

The primers sequences of the genes.

<p>The primers sequences of the genes.</p

The mRNA expression levels of PPARα, SREBP-1c, and ChREBP target genes in hepatocytes.

<p>Hepatocytes were treated with acetate and BML-275 and divided into a control group (0 mM acetate), a low-dose acetate treatment group (1.8 mM acetate), a medium-dose acetate treatment group (3.6 mM acetate), a high-dose acetate treatment group (7.2 mM acetate), a BML-275 group (10 μM BML-275), and a BML-275+acetate group (10 μM BML-275+3.6 mM acetate). Acetate (sodium acetate) was used in the form of neutralized acetic acid to avoid changing the pH of the medium. A-D: mRNA expression levels of ACO, CPT1, L-FABP, and CPT2, respectively. E-G: mRNA expression levels of ACC1, FAS, and SCD-1, respectively. * <i>p</i><0.05, ** <i>p</i><0.01 versus the control group.</p