Establishment of Stability Evaluation Criteria for the Oil-Gas Interface during Gas-Cap Gravity Flooding in Oil Reservoirs with Strong Edge-Water Drive.

A three-dimensional (3D) experimental model considering the influence of water energy is established to innovatively analyze oil-gas interface stability, and it is found that a stable gas cap with sufficient driving energy can be formed only under a stable oil and gas interface. So, the bidirectional displacement through the gas cap and edge water can be realized during the late development stage in the strong edge-water drive reservoirs. Results show that the recovery of bidirectional displacement can reach 60%, while the recovery of an unstable interface is basically below 50%. The recovery degree under a stable oil-gas interface is more than 25.63% than that of the unstable interface. Based on the Navier-Stokes equation, a "steady flow velocity u s" formula that considers the influence of multiple factors is defined, and the ratio of the flow velocity at the oil-gas interface to the gas injection rate is controlled between 0.6 and 0.85 to determine the criteria for the stable oil-gas interface. At the same time, the differentiation-hindered quasi-number (Gr) is defined to clarify the influence mechanism of various mechanical factors on gravity differentiation and the difficulty of oil and gas replacement. When Gr is equal to 1, the oil-gas interface reaches stable migration conditions. Larger formation dip angle, higher permeability, smaller oil viscosity, and lower gas injection rate are the favorable conditions for forming stable flow. The findings are recommended to be used in reservoirs with relatively homogeneous reservoirs, certain dip angles, and moderate or low oil viscosity.

Study on Screening Criteria of Gel-Assisted Polymer and Surfactant Binary Combination Flooding after Water Flooding in Strong Edge Water Reservoirs: A Case of Jidong Oilfield.

Strong edge water reservoirs have sufficient natural energy. After long-term natural water flooding development, it is in the stage of ultrahigh water cut. There is an urgent need to change the development mode and improve the development effect. Taking Jidong Oilfield as an example, the mechanism model of strong edge water reservoirs is established by using the method of numerical simulation. Then, the factors and rules affecting the effects of gel-assisted polymer and surfactant binary combination flooding are studied. The screening criteria of gel-assisted polymer and surfactant binary combination flooding in strong edge water reservoirs are obtained. The results show that the existence of edge water is not conducive to binary combination flooding. Smaller water volumetric multiples and larger oil-bearing areas are more suitable for binary combination flooding. Compared with closed reservoirs, binary combination flooding in strong edge water reservoirs is more difficult to establish a displacement pressure gradient. The reservoir with high crude oil viscosity is not suitable for binary combination flooding. Gel-assisted polymer and surfactant binary combination flooding can be adopted for reservoirs with an oil-bearing area greater than 0.2 km2, a water volumetric multiple less than 200, and oil viscosity less than 100 mPa·s. The research results are of guiding significance for the reservoir selection of gel-assisted polymer and surfactant binary combination flooding after natural water flooding.

Perioperative Exercise Intention and Influencing Factors: A Multi-Centered Cross-Sectional Study.

Objectives: This study aimed to evaluate the level and factors affecting the perioperative exercise intention in China. Design: This study was a cross-sectional survey in Southwest China. Methods: Four hundred and ninety nine participants were randomly sampled in eight medical centers from November 23, 2020 to November 27, 2020. The survey included sociodemographic information and a 24-item modified questionnaire, which aimed to evaluate the attitude toward daily exercise, perception of perioperative exercise, social support and the perioperative exercise intention. A multivariable linear regression model was used to evaluate the effect of different items on the patients' intention for perioperative exercise. Results: A total of 523 responses (95.09%) were collected and 499 (95.41%) were analyzed. The level of exercise intention of the patients during the perioperative period was: 14.83% planned to exercise every day in the hospital, 21.04% planned to exercise every other day, and 35.87% planned to exercise every week. Intensity of daily exercise (P = 0.016), positive attitude of daily exercise (P < 0.001), positive attitude of perioperative exercise (P < 0.001) and social support (P < 0.001) were positively associated with the intention for perioperative exercise. Female (P = 0.012), non-tertiary center (P = 0.011), and preoperative anxiety (P = 0.023) was negatively associated with it. Conclusions: The intention for perioperative exercise was low in Southwest China. The authors aimed to relieve preoperative anxiety, promote the education of perioperative exercise, design perioperative exercise programs, and provide more social support from medical staff and family for inpatients undergoing elective surgery.

MicroRNA-23 inhibition protects the ischemia/reperfusion injury via inducing the differentiation of bone marrow mesenchymal stem cells into cardiomyocytes.

Recently, miRNA-23 has been illustrated to play an important role in causing myocardial ischemia/reperfusion injury (MIRI), indicated that inhibition of miR-23 could protect the cardiomyocyte from MIRI. However, the underlying mechanism of miR-23 inhibition in alleviating the reperfusion-induced myocardial damage is unclear. Recognizing that the bone marrow mesenchymal stem cells (BMSCs) have the potential for pluripotent differentiation into myocardial cells, we therefore hypothesis that the BMSCs are involved in the process of miR-23 alleviating IRI. For verification, the BMSCs was established firstly and confirmed by the immunofluorescence assay and flow cytometry analysis. As results revealed that BMSCs were positive for CD44 which was known for BMSC markers, and negative expression for CD45, indicating that the BMSCs was successfully established in our work. Subsequently, we have investigated the effect of miR-23 on the expression of hyaluronan synthase-2 (Has2), a critical gene during heart morphogenesis. Results obtained by the Western-blot and qRT-PCR assay displayed that the levels of Has2 in the BMSCs treated by miR-23 inhibitor was significantly up-regulated than that of control group. Furthermore, the effect of miR-23 on promoting the transformation of BMSCs into myocardial cells was investigated. As demonstrated by the results that the expression level of the cardiac markers in BMSCs transfected with miR-23 inhibitor was remarkably elevated, indicating that inhibition of miR-23 exactly facilitated to the transformation of BMSCs into myocardial cells. The underlying mechanisms experiments showed that the Wnt1, TCF4, and the ß-catenin could be significantly elevated by treating with miR-23 inhibitor, suggesting that the activation of Wnt pathway has played a significant role in that process. Finally, the in vivo IRI antagonism effect of miR-23 inhibition was studied and results displayed that the myocardium lesions of these IR rats could be significantly recovered by treating with miR-23 inhibitor.

miR­149 promotes the myocardial differentiation of mouse bone marrow stem cells by targeting Dab2.

To investigate the role of microRNA (miR)­149 in the cardiac differentiation of mouse bone marrow mesenchymal stem cells (MSCs) in vitro, MSCs were infected with a lentivirus overexpressing miR­149 and the effect on cardiac differentiation was determined. The quantitative polymerase chain reaction results demonstrated that miR­149 promoted the expression of cardiac­specific markers in MSCs. Western blotting and a luciferase activity assay demonstrated that disabled homolog 2 (Dab2) was a direct target of miR­149. Dab2 ectopic expression and Wnt/ß­catenin signaling pathway inhibition was able to reverse the increased expression of cardiac­specific markers induced by miR­149. In conclusion, miR­149 was able to target Dab2 and promote the cardiac differentiation of mouse MSCs in vitro, which depended upon the Wnt/ß­catenin signaling pathway.

Clinical study of optical coherence tomography in the diagnosis of peripheral pulmonary artery thrombus.

BACKGROUND: Peripheral pulmonary artery thrombus (PPT) is common in the clinic. However, due to the lack of an ideal diagnostic tool, PPT cannot be quickly diagnosed and effectively treated at present. Optical coherence tomography (OCT) is a new intravascular imaging technique that is characterized by high image resolution. This technique is suitable for small vessel imaging and has the ability to distinguish red and white thrombi. OBJECTIVE: This study aimed to evaluate the value of OCT in the diagnosis of PPT and in identifying the nature of thrombi by comparing the difference in sensitivity between OCT and selective pulmonary angiography (SPA). METHODS: Highly suspected PPT patients were enrolled in this study. Pulmonary ventilation/perfusion (V/Q) mismatch pulmonary segments or peripheral pulmonary arteries were chosen. SPA was performed first, followed by OCT imaging. The diagnostic standard of thrombus with SPA was an intraluminal filling defect. The procedure and criteria for OCT diagnosis of thrombus were previously introduced in intracoronary OCT thrombus images. The diameter of the imaging vessels was measured, and they were grouped according to diameter. The diameter was <2mm in the distal segment group, 2-3mm in the middle segment group, and >3mm in the proximal segment group. The recognition abilities of intravascular thrombus with the different diameters of these two techniques were compared. Patients with obvious clinical symptoms and more red thromboses revealed by OCT were given standardized anticoagulant therapy for half a year. The clinical symptoms, 6-minute walking test and changes in the thrombus in the OCT images of these patients before and after treatment were observed. RESULTS: A total of 22 patients with highly suspected PPT were suggested to undergo V/Q inspection. Finally, 12 patients were eligible for the study. SPA and OCT were performed in 61 peripheral pulmonary arteries in all 12 patients. The ideal SPA and OCT images obtained from a total of 76 blood vessel segments were suitable for comparative analysis. A total of 62 thrombi were found by SPA. Among these, eight thrombi were in the distal segment, 29 thrombi were in the middle segment, and 25 thrombi were in the proximal segment. A total of 81 thrombi were found by OCT, among which 22 thrombi were in the distal segment, 31 were in the middle segment, and 28 were in the proximal segment. There was a significant difference between two groups in the distal segment group (P=0.013), while there was no significant difference between two groups in the middle segment group or the proximal segment group (P>0.05). In addition to all the thrombi found by SPA, OCT found other thrombi that were missed by SPA. According to previous OCT images for determining the nature of thrombi, OCT revealed 81 thrombi, of which 48 (59%) were red thrombi and 33 (41%) were white thrombi. Then, seven patients who had obvious clinical symptoms and more red thrombi in the peripheral pulmonary artery were given anticoagulant therapy for six months. After treatment, these symptoms were improved, oxygenation indexes increased, and the six-minute walking test was extended in all these patients. After anticoagulation therapy, five patients underwent OCT review. These OCT images were matched and compared before and after anticoagulation therapy. The results revealed that most of the thrombi had disappeared, and a small amount of red thrombi turned white as the volume reduced. The mean lumen area before and after treatment was 2.05±1.03mm2 and 2.86±1.24mm2, respectively, and the difference was statistically significant (P=0.035). CONCLUSION: OCT can clearly show the structure of the lumen and the wall of the peripheral pulmonary artery tube. The sensitivity of the diagnosis of PPT with a diameter of <2mm was higher than that of SPA. Moreover, OCT has the ability to distinguish between red and white thrombi, which is of guiding significance in anticoagulant therapy.