Diffusion coefficients of natural gas in foamy oil systems under high pressures

The diffusion coefficient of natural gas in foamy oil is one of the key parameters to evaluate the feasibility of gas injection for enhanced oil recovery in foamy oil reservoirs. In this paper, a PVT cell was used to measure diffusion coefficients of natural gas in Venezuela foamy oil at high pressures, and a new method for deter- mining the diffusion coefficient in the foamy oil was de- veloped on the basis of experimental data. The effects of pressure and the types of the liquid phase on the diffusion coefficient of the natural gas were discussed. The results indicate that the diffusion coefficients of natural gas in foamy oil, saturated oil, and dead oil increase linearly with increasing pressure. The diffusion coefficient of natural gas in the foamy oil at 20 MPa was 2.93 times larger than that at 8.65 MPa. The diffusion coefficient of the natural gas in dead oil was 3.02 and 4.02 times than that of the natural gas in saturated oil and foamy oil when the pressure was 20 MPa. However, the gas content of foamy oil was 16.9 times higher than that of dead oil when the dissolution time and pressure were 20 MPa and 35.22 h, respectively.

Making and Study of Moderate Pressure Glow Discharge on the Basis of Electrolytic Foamy Cathode, Prepared as the Aqueous Solution of NaHCO3

A method to generate the dynamic moderate pressure dc glow discharge on the basis of electrolytic cathode in the form of aqueous solution of sodium bicarbonate NaHCO3 is described. Photo and video images of the discharge are presented as well as the synchronized therewith “oscillograms” of current and voltage. Different phases of the discharge were discovered, one of which is a quasi-stationary glow discharge with the foamy cathode, was recorded for the first time. It was shown, that in this phase the discharge is supported by a so-called three-dimensional cathode spot, having the finite volume. The time-spatial diagram was plotted for the discharge. The Rayleigh-Taylor instability in the two-layered electrolytic cathode was recorded.

Borf-1 protein identified as a transcriptional trans-activator of bovine foamy virus

Bovine foamy virus (BFV), a member of the spumavirus subfamily of retroviruses,contains two open reading frames (ORF-1 and ORF-2) in addition to the genes coding for gag,po/and env. Borf-1 protein, encoded by BFV ORF-1, is identified as a transcriptional transactivator, which augments gene expression directed by the viral long terminal repeat (LTR).Further investigations in transient expression assays reveal that the Borf-1 responsive elements are located in the U3 domain of the LTR, upstream from position -140 ( + 1 represents the transcription initiation site), and the BFV RU5 region has an inhibitory effect in LTR-directed gene expression.

cis-acting element located in the bovine foamy virus internal promoter possesses the properties of a transcrip-tional enhancer

Bovine foamy virus encodes a transcriptional transactivitor, Tas or Borf-1, which governs the level of viral transcripts initiated by both the promoter in the long terminal repeat (LTR) and the internal promoter (IP) located in the env gene through their cis-acting targets. We have identified and characterized a 72 bp TBS (Borf-1) responsive element located in BFV3026, internal promoter (TREIP) by deletion mutant and transient expression assay. This cis-acting target element in the internal promoter has the properties of a transcriptional enhancer which functions independently of its orientation, position and also in heterologous promoters (BFV LTR and bovine immunodeficiency virus, BIV LTR). Alignments reveal that there are positional similarity and sequence homology among BFV TREIP, SFV-1 TREIP proximal element and SFV-3 TREIPH, which suggests that this kind of cis-acting elements possesses some common functional character.

Lnc-RP5 Regulates the mi R-129-5p/Notch1/PFV Internal Promoter Axis to Promote the Expression of the Prototype Foamy Virus Transactivator Tas

Prototype foamy virus(PFV)is a unique retrovirus that infects animals and humans and does not cause clinical symptoms.Long noncoding RNAs(lncRNAs)are believed to exert multiple regulatory functions during viral infections.Previously,we utilized RNA sequencing(RNA-seq)to characterize and identify the lncRNA lnc-RP5-1086 D14.3.1-1:1(lnc-RP5),which is markedly decreased in PFV-infected cells.However,little is known about the function of lnc-RP5 during PFV infection.In this study,we identified lnc-RP5 as a regulator of the PFV transcriptional transactivator(Tas).Lnc-RP5 enhanced the activity of the PFV internal promoter(IP).The expression of PFV Tas was found to be promoted by lnc-RP5.Moreover,mi R-129-5 p was found to be involved in the lnc-RP5-mediated promotion of PFV IP activity,while the Notch1 protein suppressed the activity of PFV IP and the expression of Tas.Our results demonstrate that lnc-RP5 promotes the expression of PFV Tas through the miR-129-5 p/Notch1/PFV IP axis.This work provides evidence that host lnc RNAs can manipulate PFV replication by employing mi RNAs and proteins during an early viral infection.

Membrane-spanning domain of bovine foamy virus transmembrane protein having cytotoxicity

Foamy viruses(FVs)have broad cellular tropism infecting vertebrates from fish to human being,which indicates that Env protein has a high capability for membrane fusion.Conservative features in all FV transmembrane(TM)proteins include a region of hydrophobic domain called membrane-spanning domain(MSD),which contains several stretches of hydrophobic amino acids.To investigate whether these features were associated with the cytotoxicity effect of TM on Escherichia coli,a series of mutants were constructed and expressed in the E.coli BL21(DE3)using pET-32a(+)as expressing vector.The results showed that only TM3 without MSD was expressed in E.coli,whereas the other two containing full or part of the MSD(TM1 and TM2)could not be expressed.Furthermore,the bacterial amount and living bacteria analysis revealed that the cytotoxicity of TM was dependent on its MSD,especially on the stretches of hydrophobic amino acids.Western blotting analysis showed that TM3 protein was purified with affinity purification.

The pathology of unusual subtypes of prostate cancer

There are some current literatures describing the morphologic change of prostate carcinoma variants. Some subtypes do not respond to hormone deprivation therapy, for example adenosquamous and squamous cell carcinoma （SQCC）, basaloid and adenoid cystic carcinoma （ACC）, small cell carcinoma （SmCC）, sarcomatoid carcinoma, urothelial carcinoma; some are defined in special Gleason grade, some develop different prognosis. So, it is very important to identify these rare subtypes to avoid misdiagnosis. In this review, we aim to describe the typical clinicopathological features of the rare variants of prostate cancer, including prostate acinar adenocarcinoma morphologic variants.

Foaminess of Refining Slags System

The experiments on the foaminess of the CaO-MgO-Al2O3 -SiO2 -CaF2 refining slag system have been carried out. The obtained results are as followst (1) relative foaming height linearly increases with the increasing of the flowrate of blowing gas; (2) the proper content of MgO is about 11% when slag basicity B<2.5 and it should lower when slag basicity will be higher; (3) the better content of Al2O3, (MgO)+(Al2O3 ) is 15% and 20 % ～ 26 % respectively at the range of lower basicities; (4) the effect of slag basicity on the foaminess is complex and its optimizing vaiue is 1.9 at the specific contents of MgO, Al2O3 and CaF2.

CO2 flooding strategy to enhance heavy oil recovery

CO_(2) flooding is one of the most promising techniques to enhance both light and heavy oil recovery.In light oil recovery,the production pressure in CO_(2) flooding in general keeps constant in order to maintain the miscibility of injected CO_(2) and crude oil;while in heavy oil recovery,a depleting pressure scheme may be able to induce foamy oil flow,thus the oil recovery could be further enhanced.In this study,different pressure control schemes were tested by 1-D core-flooding experiments to obtain an optimized one.Numerical simulations were conducted to history match all experimental data to understand the mechanisms and characteristics of different CO_(2) flooding strategies.For the core-flooding experiments,1500 mD sandstone cores,formation brine and a heavy oil sample with a viscosity of about 869.3 cp at reservoir condition(55℃ and 11 MPa)were used.Before each CO_(2) flooding test,early stage water-flooding was conducted until the water cut reached 90%.Different CO_(2) injection rates and production pressure control strategies were tested through core-flooding experiments.Experimental results indicated that a slower CO_(2) injection rate(2 ml/min)led to a higher recovery factor from 31.1%to 36.7%,compared with a high CO_(2) injection rate of 7 ml/min;for the effects of different production strategies,a constant production pressure at the production port yielded a recovery factor of 31.1%;while a pressure depletion with 47.2 kPa/min at the production port yielded 7%more oil recovery;and the best pressure control scheme in which the production pressure keeping constant during CO_(2) injection period,then depleting the model pressure with the injector shut-in yielded a recovery factor of 42.5%of the initial OOIP.For the numerical simulations study,the same oil relative permeability curve was applied to match the experimental results to all tests.Different gas relative permeability curves were obtained when the production pressure schemes are different.A much lower gas relative permeability curve and a higher critical gas saturation were achieved in the best pressure control scheme case compared to other cases.The lower gas relative permeability curve indicates that foamy oil was formed in the pressure depletion processes.Through this study,it is suggested that the pressure control scheme can be optimized in order to maximize the CO_(2) injection performance for enhanced heavy oil recovery.