A Probabilistic Approach for Multiscale Poroelastic Modeling of Mature Organic-Rich Shales

Organic-rich shales have been recognized as one of the most important energy resources in the world due to their ubiquitous presence. However, there are numerous engineering challenges serving as obstacles for exploiting these geo-materials with multiscale microstructure. This work addresses an important aspect of engineering challenges in understanding the complex behavior of organic-rich source rocks, namely their anisotropic poroelastic behavior at multiple scales. To this end, we utilize a framework obtained by combining experimental characterization, physically-based modeling and uncertainty quantification that spans and integrates scales from nanoscale to macroscale. The multiscale models play a crucial role in predicting macroscale mechanical properties of organic-rich shales based on the available information on poromechanical properties in microscale. Recently a three-level multiscale model has been developed that spans from the nanometer length scale of organic-rich shales to the scale of macroscopic composite. This approach is powerful in capturing the homogenized/effective properties/behavior of these geomaterials. However, this model ignores the fluctuation/uncertainty in mechanical and compositional model parameters. As such the robustness and reliability of these estimates can be questioned in view of different sources of uncertainty, which in turn affect the requisite information based on which the models are constructed. In this research, we aim to develop a framework to systematically incorporate the main sources of uncertainty in modeling the multiscale behavior of organic-rich shales, and thus take the existing model one step forward. Particularly, we identify and model the uncertainty in main model parameters at each scale such as porosity and elastic properties. To that end, maximum entropy principle and random matrix theory are utilized to construct probabilistic descriptions of model parameters based on available information. Then, to propagate uncertainty across different scales the Monte Carlo simulation is carried out and consequently probabilistic descriptions of macro-scale properties are constructed. Furthermore, a global sensitivity analysis is carried out to characterize the contribution of each source of uncertainty on the overall response. Finally, methodological developments will be validated by both simulation and experimental test database

Experimental and numerical study of elasto-inertial focusing in straight channels.

Elasto-inertial microfluidics has drawn significant attention in recent years due to its enhanced capabilities compared to pure inertial systems in control of small microparticles. Previous investigations have focused mainly on the applications of elasto-inertial sorting, rather than studying its fundamentals. This is because of the complexity of simulation and analysis, due to the presence of viscoelastic force. There have been some investigative efforts on the mechanisms of elasto-inertial focusing in straight channels; however, these studies were limited to simple rectangular channels and neglected the effects of geometry and flow rates on focusing positions. Herein, for the first time, we experimentally and numerically explore the effects of elasticity accompanying channel cross-sectional geometry and sample flow rates on the focusing phenomenon in elasto-inertial systems. The results reveal that increasing the aspect ratio weakens the elastic force more than inertial force, causing a transition from one focusing position to two. In addition, they show that increasing the angle of a channel corner causes the elastic force to push the particles more efficiently toward the center over a larger area of the channel cross section. Following on from this, we proposed a new complex straight channel which demonstrates a tighter focusing band compared to other channel geometries. Finally, we focused Saccharomyces cerevisiae cells (3-5 μm) in the complex channel to showcase its capability in focusing small-size particles. We believe that this research work improves the understanding of focusing mechanisms in viscoelastic solutions and provides useful insights into the design of elasto-inertial microfluidic devices

Computational inertial microfluidics:a review

Since the discovery of inertial focusing in 1961, numerous theories have been put forward to explain the migration of particles in inertial flows, but a complete understanding is still lacking. Recently, computational approaches have been utilized to obtain better insights into the underlying physics. In particular, fundamental aspects of particle focusing inside straight and curved microchannels have been explored in detail to determine the dependence of focusing behavior on particle size, channel shape, and flow Reynolds number. In this review, we differentiate between the models developed for inertial particle motion on the basis of whether they are semi-analytical, Navier-Stokes-based, or built on the lattice Boltzmann method. This review provides a blueprint for the consideration of numerical solutions for modeling of inertial particle motion, whether deformable or rigid, spherical or non-spherical, and whether suspended in Newtonian or non-Newtonian fluids. In each section, we provide the general equations used to solve particle motion, followed by a tutorial appendix and specified sections to engage the reader with details of the numerical studies. Finally, we address the challenges ahead in the modeling of inertial particle microfluidics for future investigators

Regulation of CYP3A Gene Expression in Human HepG2 Hepatoma Cells.

Human HepG2 hepatoma cells are used widely as a replicating cell system that expresses numerous liver-specific functions, including those associated with the biotransformation of foreign chemicals. In the work presented here the ability of this cell line to reproduce the in vivo modulation of CYP3A4, CYP3A5, CYP3A7, hGRa and hPXR gene expression by classical xenobiotic cytochrome P450 3A isoenzyme inducers was studied. Transfection experiments using a plasmid construct containing 1 kb of the proximal region of CYP3A4 driving an alkaline phosphatase reporter cDNA did not reliably reproduce the in vivo activation of this promoter by dexamethasone or rifampicin even after co-transfection with hGRa or hPXR expression vectors. RT-PCR experiments were performed as an alternative technique for direct investigation of CYP3A and hPXR mRNA induction. The results showed that HepG2 cells constitutively express hGRa, hPXR, RXR, SRC-1, HNF-4, CYP3A5 and CYP3A7 but not CYP3A4 mRNAs. This is the first time that the expression of CYP3A5 mRNA has been identified in HepG2 cells. The results also demonstrated that the expression of hPXR, CYP3A5 and CYP3A7 was induced by dexamethasone or rifampicin in cells at passages 5 and 10 (after resuscitation from storage) but not at passages 15 and 20, unless the cells were dosed in serum-free medium. The results are in agreement with induction experiments performed by other authors and show that HepG2 cells can be used as a suitable in vitro system for the study of CYP3A gene induction by xenobiotics. However, the pattern of gene expression more closely resembles that in the human foetal liver and thus HepG2 cells could be of most use as an in vitro model of foetal drug metabolism and gene modulation

Regulation of CYP3A Gene Expression in Human HepG2 Hepatoma Cells.

Human HepG2 hepatoma cells are used widely as a replicating cell system that expresses numerous liver-specific functions, including those associated with the biotransformation of foreign chemicals. In the work presented here the ability of this cell line to reproduce the in vivo modulation of CYP3A4, CYP3A5, CYP3A7, hGRa and hPXR gene expression by classical xenobiotic cytochrome P450 3A isoenzyme inducers was studied. Transfection experiments using a plasmid construct containing 1 kb of the proximal region of CYP3A4 driving an alkaline phosphatase reporter cDNA did not reliably reproduce the in vivo activation of this promoter by dexamethasone or rifampicin even after co-transfection with hGRa or hPXR expression vectors. RT-PCR experiments were performed as an alternative technique for direct investigation of CYP3A and hPXR mRNA induction. The results showed that HepG2 cells constitutively express hGRa, hPXR, RXR, SRC-1, HNF-4, CYP3A5 and CYP3A7 but not CYP3A4 mRNAs. This is the first time that the expression of CYP3A5 mRNA has been identified in HepG2 cells. The results also demonstrated that the expression of hPXR, CYP3A5 and CYP3A7 was induced by dexamethasone or rifampicin in cells at passages 5 and 10 (after resuscitation from storage) but not at passages 15 and 20, unless the cells were dosed in serum-free medium. The results are in agreement with induction experiments performed by other authors and show that HepG2 cells can be used as a suitable in vitro system for the study of CYP3A gene induction by xenobiotics. However, the pattern of gene expression more closely resembles that in the human foetal liver and thus HepG2 cells could be of most use as an in vitro model of foetal drug metabolism and gene modulation

In vitro and in vivo study of the antibacterial effects of Nigella sativa methanol extract in dairy cow mastitis

Objective: Nigella Sativa (N. Sativa) seeds were used in traditional medicine for the treatment of a variety of diseases. The seed extracts and oil of this plant have shown various pharmacological properties including antimicrobial actions. In this study, the in vitro and in vivo antibacterial effects of methanol extract of the seeds against pathogenic bacteria causing mastitis in cows have been investigated. Materials and methods: in in vivo experiments, 10 cows with mastitis were treated by local injection of different concentrations of methanol extract of the seeds into the infected breasts. In in vitro experiments, the microorganisms were collected from the same infected breasts and used for the assessment of the antimicrobial effects of the extract by means of agar dilution and disk diffusion methods.  Results and conclusion: The extract showed significant in vitro and in vivo inhibitory effects on causative organisms compared to standard drugs and also induced healing of the disease. This is the first veterinary experiment, to our knowledge, that investigated the antibacterial effects of Nigella sativa

Sonographic cervical parameters in predicting spontaneous preterm birth in high-risk pregnant women

"n 800x600 Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";} Background: Preterm delivery is a relevant public health problem. The aim of this study was to evaluate the association between spontaneous preterm delivery (SPTD) before 35 and 37 weeks of gestational age and the measurement of the cervix length, cervical funneling and Cervical Gland Area (CGA), in high risk pregnant population."n"nMethods: A prospective cohort of 200 women carrying high risk pregnancies was evaluated by transvaginal sonography between 14th and 28th gestational weeks. The data were analyzed using statistical methods. A multiple linear regression model was estimated in order to examine the relationship between the gestational age at delivery and the cervical markers. A multiple logistic regression was estimated in order to analyze the factors associated to spontaneous preterm delivery and the transvaginal sonographic markers."n"nResults: Cervical length less than 18 mm and the presence of cervical funneling presented a statistically significant association with spontaneous preterm delivery before 35 weeks. The nondetection of Cervical Gland Area demonstrated a strong association with spontaneous preterm delivery before (p=0.0001, OR=169.1, CI=2.6-3.1) and 35th and 37th gestational week (p=0.001, OR=115, CI=2.12-3.5). The multiple logistic regression analysis suggested the non-detection of CGA as the only variable to reveal statistically significance association with spontaneous preterm delivery."n"nConclusion: Based on results of present study the absence of cervical gland area (CGA) can be a new and important ultrasound marker for predicting spontaneous preterm delivery and needs to confirm with future multicenter investigations