Large Eddy Simulation of the Two-Phase Reactive Flow Field in a Single Sector Laboratory Scale Rich-Quench-Lean Combustion Chamber

This work presents Large Eddy Simulation (LES) of a laboratory scale RQL combustion chamber. Simulations were carried out using an in-house LES-code for reactive, two-phase, adiabatic flow implemented in OpenFOAM. The twophase turbulent reactive flow is modeled following a coupled Euler-Lagrange approach in combination with a presumed Joint Probability Density Function (JPDF) combustion model and tabulated chemistry. The reaction progress of laminar premixed flames is tabulated using a kerosene-surrogate chemical reaction mechanism. Calculated and measured velocity fields of the gaseous and liquid phase are compared to each other for reacting and non-reacting conditions. The results show excellent agreement between the two-dimensional flow fields derived from PIV and LES for the non-reactive case. The results of the reactive case show very good agreement for the velocity field

miR-16 and miR-21 Expression in the Placenta Is Associated with Fetal Growth

BACKGROUND: Novel research has suggested that altered miRNA expression in the placenta is associated with adverse pregnancy outcomes and with potentially harmful xenobiotic exposures. We hypothesized that aberrant expression of miRNA in the placenta is associated with fetal growth, a measurable phenotype resulting from a number of intrauterine factors, and one which is significantly predictive of later life outcomes. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed 107 primary, term, human placentas for expression of 6 miRNA reported to be expressed in the placenta and to regulate cell growth and development pathways: miR-16, miR-21, miR-93, miR-135b, miR-146a, and miR-182. The expression of miR-16 and miR-21 was markedly reduced in infants with the lowest birthweights (p<0.05). Logistic regression models suggested that low expression of miR-16 in the placenta predicts an over 4-fold increased odds of small for gestational age (SGA) status (p = 0.009, 95% CI = 1.42, 12.05). Moreover, having both low miR-16 and low miR-21 expression in the placenta predicts a greater increase in odds for SGA than having just low miR-16 or miR-21 expression (p<0.02), suggesting an additive effect of both of these miRNA. CONCLUSIONS/SIGNIFICANCE: Our study is one of the first to investigate placental miRNA expression profiles associated with birthweight and SGA status. Future research on miRNA whose expression is associated with in utero exposures and markers of fetal growth is essential for better understanding the epigenetic mechanisms underlying the developmental origins of health and disease

Impact on cell to plasma ratio of miR-92a in patients with acute leukemia: in vivo assessment of cell to plasma ratio of miR-92a

<p>Abstract</p> <p>Background</p> <p>Plasma microRNA (miRNA) has become a promising biomarker for detecting cancer; however, it remains uncertain whether miRNA expression levels in plasma reflect those in tumor cells. Our aim was to determine the biological relevance of miR-92a, which has been implicated as an oncomiR in both plasma and leukemia cells in patients with acute leukemia and to evaluate whether it could be a novel biomarker for monitoring these patients.</p> <p>Results</p> <p>We quantified the expression level of miR-92a in both cells and plasma by reverse transcription polymerase chain reaction in 91 patients with acute leukemia. We also determined miR-92a expression levels in peripheral blood mononuclear cells (PBMNC) from normal controls. We compared miR-92a expression in plasma with its expression in leukemia cells. Synthetic anti-miR-92a inhibitor was transfected into Raji and OM9;22 cells, and apoptosis was assessed. For in vivo assessment, 6-week-old female nude mice were injected with U937 cells, and miR-92a expression in plasma and tumors was measured. The level of miR-92a expression in fresh leukemia cells was highly variable compared with PBMNC, but significantly lower compared with CD34-positive cells obtained from healthy volunteers. We also noticed that miR-92a was preferentially expressed in acute lymphoblastic leukemia (ALL) cells in comparison with acute myeloid leukemia (AML) cells. More specifically, cellular miR-92a expression was significantly increased in a subset of ALL cells, and ALL patients with overexpressed miR-92a had poor prognoses. The anti-miR-92a inhibitor-treated Raji and OM9;22 cells revealed an increase of apoptotic cells. Notably, the cell to plasma ratio of miR-92a expression was significantly higher in both AML and ALL cells compared with PBMNC from healthy volunteers. In tumor-bearing mice, the plasma miR-92a level was significantly decreased in accordance with tumor growth, while tumor tissue was strongly positive for miR-92a.</p> <p>Conclusions</p> <p>The miR-92a expression in leukemia cells could be a prognostic factor in ALL patients. The inverse correlation of miR-92a expression between cells and plasma and the cell to plasma ratio may be important to understanding the clinical and biological relevance of miR-92a in acute leukemia.</p

Differences in the Properties and Mirna Expression Profiles between Side Populations from Hepatic Cancer Cells and Normal Liver Cells

AIMS: Because hepatic cancer stem cells (HCSCs) are believed to derive from the conversion of hepatic normal stem cells (HNSCs), the identification of the differences that distinguish HCSCs from HNSCs is important. METHODS: The HCC model was established in F344 rats by DEN induction. Using FACS analysis, side population cells from HCC (SP-HCCs) were isolated from the epithelial-like cells of HCC tissues, and the side population cells from normal liver (SP-NLCs) were isolated from syngeneic normal liver cells. The expression of stem cell markers was detected in both freshly isolated and amplified subpopulations. After induction with HGF, the differentiation of each subpopulation was analyzed by detection of early and late liver markers. In vivo, the biological characteristics of SP-HCCs and SP-NLCs were analyzed by repairing injured livers or forming tumors in nude mice. In addition, the expression of miRNAs was examined in both populations by miRNA array and QRT-PCR. RESULTS: SP-NLCs and SP-HCCs were 4.30±0.011% and 2.100±0.010% of the whole population, respectively. Both SP-NLCs and SP-HCCs displayed greater expression of stem cell markers (CD133 and EpCAM) than NSP-NLCs and NSP-HCCs, respectively (P<0.01), both after fresh isolation and amplification. Upon HGF induction, SP-NLCs generated many ALB positive cells and few CK-7 positive cells, but NSP-NLCs could generate only ALB positive cells. In contrast, SP-HCCs gave rise to only AFP positive cells. As few as 5 × 10⁵ SP-NLCs were capable of repairing liver injury, while the same number of NSP-NLCs could not repair the liver. Furthermore, only 1 × 10⁴ SP-HCCs were necessary to initiate a tumor, while NSP-HCCs could not form a tumor. Compared to SP-NLCs, 68 up-regulated and 10 down-regulated miRNAs were present in SP-HCCs (P<0.01). CONCLUSION: Based on the decisive roles of some miRNAs in the genesis of HCSCs, miRNAs may contribute to the different characteristics that distinguish SP-HCCs from SP-NLCs

A round robin approach to the analysis of bisphenol a (BPA) in human blood samples

BACKGROUND: Human exposure to bisphenol A (BPA) is ubiquitous, yet there are concerns about whether BPA can be measured in human blood. This Round Robin was designed to address this concern through three goals: 1) to identify collection materials, reagents and detection apparatuses that do not contribute BPA to serum; 2) to identify sensitive and precise methods to accurately measure unconjugated BPA (uBPA) and BPA-glucuronide (BPA-G), a metabolite, in serum; and 3) to evaluate whether inadvertent hydrolysis of BPA-G occurs during sample handling and processing. METHODS: Four laboratories participated in this Round Robin. Laboratories screened materials to identify BPA contamination in collection and analysis materials. Serum was spiked with concentrations of uBPA and/or BPA-G ranging from 0.09-19.5 (uBPA) and 0.5-32 (BPA-G) ng/mL. Additional samples were preserved unspiked as ‘environmental’ samples. Blinded samples were provided to laboratories that used LC/MSMS to simultaneously quantify uBPA and BPA-G. To determine whether inadvertent hydrolysis of BPA metabolites occurred, samples spiked with only BPA-G were analyzed for the presence of uBPA. Finally, three laboratories compared direct and indirect methods of quantifying BPA-G. RESULTS: We identified collection materials and reagents that did not introduce BPA contamination. In the blinded spiked sample analysis, all laboratories were able to distinguish low from high values of uBPA and BPA-G, for the whole spiked sample range and for those samples spiked with the three lowest concentrations (0.5-3.1 ng/ml). By completion of the Round Robin, three laboratories had verified methods for the analysis of uBPA and two verified for the analysis of BPA-G (verification determined by: 4 of 5 samples within 20% of spiked concentrations). In the analysis of BPA-G only spiked samples, all laboratories reported BPA-G was the majority of BPA detected (92.2 – 100%). Finally, laboratories were more likely to be verified using direct methods than indirect ones using enzymatic hydrolysis. CONCLUSIONS: Sensitive and accurate methods for the direct quantification of uBPA and BPA-G were developed in multiple laboratories and can be used for the analysis of human serum samples. BPA contamination can be controlled during sample collection and inadvertent hydrolysis of BPA conjugates can be avoided during sample handling

Global Analysis for a Delay-Distributed SIR Epidemic Model

One of the most tools for describing the incubation period in the epidemiological dynamic models is the distributed delays. In this paper, we propose a delay-distributed SIR epidemic model with a nonlinear incidence rate. Using the Lyapunov theory and LaSalle’s principle, we show the global asymptotic stability of the disease-free and the endemic equilibria. This analysis extends and performs existing results. <br> En épidémiologie le retard joue un rôle très important dans la représentation de la période d’incubation. Dans ce travail, nous étudions un modèle SIR à retard distribué, avec une fonction d’incidence non linéaire. Pour analyser la stabilité globale du point d’équilibre sans maladie et du point d’équilibre endémique, nous utilisons la théorie de Lyapunov et le principe d’invariance de LaSalle