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Summary Acoustic velocity is one of the key thermodynamic properties that can supplement phase behavior or pressure/volume/temperature (PVT) measurements of pure substances and mixtures. Several important fluid properties are relatively difficult to obtain through traditional measurement techniques, correlations, or equation of state (EOS) models. Acoustic measurements offer a simpler method to obtain some of these properties. In this work, we used an experimental method based on ultrasonic pulse-echo measurements in a high-pressure/high-temperature (HP/HT) cell to estimate acoustic velocity in fluid mixtures. We used this technique to estimate related key PVT parameters (such as compressibility), thereby bridging gaps in essential data. In particular, the effect of dilution with methane (CH4) and carbon dioxide (CO2) at pressures from 15 to 62 MPa and temperatures from 313 to 344 K is studied for two reservoir fluid systems to capture the effect of the gas/oil ratio (GOR) and density variations on measured viscosity and acoustic velocity. Correlative analysis of the acoustic velocity and viscosity data were then performed to develop an empirical correlation that is a function of GOR. Such a correlation can be useful for improving the interpretation of the sonic velocity response and the calibration of viscosity changes when areal fluid properties vary with GOR, especially in disequilibrium systems. In addition, under isothermal conditions, the acoustic velocity of a live oil decreases monotonically with decreasing pressure until the saturation point where the trend is reversed. This observation can also be used as a technique to estimate the saturation pressure of a live oil or as a byproduct of the target experiments. It supplements the classical pressure/volume measurements to determine the bubblepoint pressure.

Summary Accurate estimation of relative permeability is one of the key parameters for decision making in upstream applications from project appraisal to field development and evaluation of various field development options. In this study, we identify Euler number (Arns et al. 2001) (a quantitative measure of fluid connectivity/distribution) and saturation as being the first-order predictors of relative permeability and develop a reliable correlation between them using machine learning of experimental special core analysis (SCAL) data and pore network simulation results. In order to achieve our objective, first, we developed a machine-learning model based on the random forest algorithm (Breiman 2001) to analyze specific SCAL data that indicates a key missing feature in the traditional saturation-based relative permeability prediction. We identified this missing feature and proposed the Euler characteristic as a potential first-order predictor of relative permeability in combination with in-situ fluid saturations. We generated “artificial” relative permeability data using pore network simulation (Valvatne and Blunt 2004) by systematically varying a set of key parameters such as pore geometry, wettability, and saturation history. Subsequently, we used machine learning to rank the importance of each parameter and identify possible correlative responses to those selected variables. At a fixed saturation (zero-dimensional volumetric abundance) and Euler number coordinates, the relative permeability is very consistent and varies insignificantly across different cases, suggesting these two parameters as first-order predictors. Euler number characterizes the fluid connectivity/distribution, while saturation represents the net volumetric fluid quantity. We believe that Euler number could be the missing first-order predictor in traditional saturation-based predictive relative permeability models, especially for connected pathway dominated flow regime. Finally, we identified the quantitative relationship between relative permeability and Euler characteristic, and present a reliable correlation to determine the relative permeability on the basis of Euler number and saturation.

In the present study, we performed a comparative stage specific pathological and molecular marker evaluation of TMPRSS2-ERG fusion and PTEN loss-driven (TMPRSS2-ERG.Pten(flox/flox)) versus non-fusion driven prostate tumorigenesis (Hi-Myc) in mice. Anterior, ventral, and dorsolateral prostates were collected from mice at different ages (or time points post-Cre induction). Results indicated that growth and progression of prostatic intraepithelial lesions to adenocarcinoma stages occurred in both mice models albeit at different rates. In the TMPRSS2-ERG. Pten(flox/flox) mice, the initiation of tumorigenesis was slow, but subsequent progression through different stages became increasingly faster. Adenocarcinoma stage was reached early on; however, no high-grade undifferentiated tumors were observed. Conversely, in the Hi-Myc(+/−) mice, tumorigenesis initiation was rapid; however, progression through different stages was relatively slower and it took a while to reach the more aggressive phenotype stage. Nevertheless, at the advanced stages in the Hi-Myc(+/−) mice, high-grade undifferentiated tumors were observed compared to the later stage tumors observed in the fusion-driven TMPRSS2-ERG. Pten(flox/flox) mice. These results were corroborated by the stage specific-pattern in the molecular expression of proliferation markers (PCNA and c-Myc); androgen receptor (AR); fusion-resultant over expression of ERG; Prostein (SLC45-A3); and angiogenesis marker (CD-31). Importantly, there was a significant increase in immune cell infiltrations, which increased with the stage of tumorigenesis, in the TMPRSS2-ERG fusion positive tumors relative to fusion negative tumors. Together, these findings are both novel and highly significant in establishing a working preclinical model for evaluating efficacy of interventions during different stages of tumorigenesis in TMPRSS2-ERG fusion driven PCa.

Blocking Plasmodium, the causative agent of malaria, at the asymptomatic pre-erythrocytic stage would abrogate disease pathology and prevent transmission. However, the lack of well-defined features within vaccine-elicited antibody responses that correlate with protection represents a major roadblock to improving on current generation vaccines. We vaccinated mice (BALB/cJ and C57BL/6J) with Py circumsporozoite protein (CSP), the major surface antigen on the sporozoite, and evaluated vaccine-elicited humoral immunity and identified immunological factors associated with protection after mosquito bite challenge. Vaccination achieved 60% sterile protection and otherwise delayed blood stage patency in BALB/cJ mice. In contrast, all C57BL/6J mice were infected similar to controls. Protection was mediated by antibodies and could be passively transferred from immunized BALB/cJ mice into naïve C57BL/6J. Dissection of the underlying immunological features of protection revealed early deficits in antibody titers and polyclonal avidity in C57BL/6J mice. Additionally, PyCSP-vaccination in BALB/cJ induced a significantly higher proportion of antigen-specific B-cells and class-switched memory B-cell (MBCs) populations than in C57BL/6J mice. Strikingly, C57BL/6J mice also had markedly fewer CSP-specific germinal center experienced B cells and class-switched MBCs compared to BALB/cJ mice. Analysis of the IgG γ chain repertoires by next generation sequencing in PyCSP-specific memory B-cell repertoires also revealed higher somatic hypermutation rates in BALB/cJ mice than in C57BL/6J mice. These findings indicate that the development of protective antibody responses in BALB/cJ mice in response to vaccination with PyCSP was associated with increased germinal center activity and somatic mutation compared to C57BL/6J mice, highlighting the key role B cell maturation may have in the development of vaccine-elicited protective antibodies against CSP.

Vertical Axis Wind Turbines (VAWTs) are mostly manufactured keeping in mind the site and conditions that the wind turbine would face. There is a need to know which type of VAWT would be optimal in the conditions present at the installation site. The major factors involved are blade profile, wind velocity and blade pitch angle. This study is undertaken to study these factors and their effects on influencing the efficiency of the VAWT. A model has been made of a Darrieus VAWT with H-rotor design and is analyzed using CFD. An Iso-surface mesh is made on the model with a cylindrical air-filled domain and a κ-ε turbulence model is applied to study the effects of the wind-and-turbine blade interaction. The domain inlet indicates wind velocity; outlet is set to zero atmospheric gauge pressure and the pressure distribution across the turbine blade wall is measured. The top bottom walls of the domain are not part of the interaction. The study shows that the NACA0012 blade profile fares better than the other profiles across the range of wind velocities. However, it is less efficient with an increase in blade pitch angle for the same value of velocity. NACA0015 blade profile gives good performance when it has a zero pitch angle for intermediate and high wind velocities.