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For low-permeability sandstone reservoirs, CO2 huff and puff is an effective method for increasing oil recovery. Commonly, sandstone formations with low permeability have diverse pore and throat sizes and a complex pore-throat structure, which essentially affects the flow characteristics of CO2 and oil in the formation and further the CO2 huff and puff performance. It is necessary to understand the recovery degree of various microscale pore sizes under different operational parameters during CO2 huff and puff in tight sandstones. In this work, several experiments of cyclic CO2 injection are conducted with sandstone core samples with low permeability. Before and after the injection, the T 2 spectra of the sandstone cores are compared using the NMR technique. We then discuss the micro residual oil distribution and recovery degree in different pores, such as micropores (<1 ms), small pores (1-10 ms), medium pores (10-100 ms), and macropores (>100 ms). It is found that the recovery degree in the different pores increases as the pore size increases. Oil can be recovered more easily from macropores and medium pores during the cyclic CO2 injection. The oil contained in micropores is relatively difficult to extract considering a high capillary force under immiscible conditions. It is found that the total recovery degree increases with the increase in soaking time. However, such a recovery degree increment in small pores is not as large as that achieved in medium and large pores. With the CO2 injection volume increase, the total recovery degree increases. When the CO2 injection volume is less than 1.5 PV, it is challenging to extract the oil from micropores and small pores. As the cycle number increases, the cyclic oil recovery decreases, and most of the oil is produced in the first cycle. This suggests that under the experimental conditions of this study, the cycle number of CO2 huff and puff shall not be more than 3. This work is important to further understand the CO2 huff and puff process for improving oil recovery in sandstone reservoirs with low permeability.
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BACKGROUND: Coronavirus disease 2019 (COVID-19) pandemic has become the most severe global health issue. Abnormal liver functions are frequently reported in these patients. However, liver function abnormality was often overlooked during COVID-19 treatment, and data regarding liver functions after cure of COVID-19 is limited. This study aimed to reveal the changes of liver function tests (LFTs) during hospitalization, and its clinical significance in patients with COVID-19. METHODS: In this retrospective, bi-center study, a total of 158 hospitalized patients diagnosed with COVID-19 in China were included from January 22nd, 2020 to February 20th, 2020. Clinical features, laboratory parameters including LFTs, and treatment data were collected and analyzed. LFTs included alanine transaminase, aspartate aminotransferase, alkaline phosphatase, gamma-glutamyl transferase, and total bilirubin. Patients were considered with abnormal LFTs when any value of these tests was higher than upper limit of normal. RESULTS: Of 158 patients with COVID-19, 67 (42.41%) patients had abnormal LFTs on admission and another 50 (31.65%) patients developed abnormal LFTs during hospitalization. The incidence of LFTs abnormality in severe COVID-19 cases was significantly higher than non-severe cases. All LFTs in COVID-19 patients were correlated with oxygenation index. There was no statistical difference in treatment between the patients with or without liver test abnormalities. By the time of discharge, there were still 64 (40.50%) patients with abnormal LFTs. Logistic regression analysis identified younger age, hypertension and low lymphocyte counts as independent risk factors for persistent abnormal LFTs during hospitalization. CONCLUSION: Liver function tests abnormality was common in COVID-19 patients and was more prevalent in severe cases than in non-severe cases. A substantial percentage of patients still had abnormal LFTs by the time of discharge.
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Polymer microsphere (PM) profile control has been attributed to improving sweep efficiency during the oil development process. The critical factors for PM conformance control are the plugging properties controlled by matching the relationship between the throat diameter and particle size and the injection parameters. A new matching relationship between the reservoir and PM based on the function of blocking rate and the ratio of throat diameter to microsphere diameter (C R) is established to choose the most appropriate PM size. The blocking rate indicates that it will get the most excellent plugging effect when C R is 0.5. The displacement experiments under different injection concentrations and other injection volumes show that the blocking rate is increased by injection concentration and finally stabilized. A similar trend is presented between the injection volume and plugging rate. The optimal injection concentration is 0.5%, and the optimal injection volume is 0.3 PV. According to the new size selection method and injection parameter optimal method, PM100 chooses to conduct field application. PM100 presents a good performance with a success rate of 37.5% and a validity period of more than 120 days, and its daily oil production rate increased 1.7 times, on average, and finally, the total oil increase is 556 t. The optimal size microsphere shows a good EOR effect, which indicates that this size selection method is reasonable.
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Much research has been carried out on nanoscale polymer microspheres (PMs) in laboratories in recent years. However, there are limited reports on the practical application of nanoscale PMs in ultralow permeability reservoirs. This paper reports a field application case of nanoscale PMs for in-depth profile control in the ultralow permeability oil reservoir. In the paper, the characteristics of the reservoir and the problems faced during development are analyzed in detail. Then, the PMs with calibration diameters of 300 nm and 800 nm are researched by evaluation experiments, and are selected for in-depth profile control in the ultralow permeability oil reservoir. Finally, according to the effect of the pilot application, the performance of PMs is evaluated, and a more suitable size for the pilot test reservoir is determined. The experiment's results show that the PMs have a good capacity for swelling and plugging. For the PMs with a calibration diameter of 300 nm, the final equilibrium swelling ratio is 56.2 nm·nm-1, and the maximum resistance coefficient and the blocking rate after swelling are 3.7 and 70.31%, respectively. For the PMs with a calibration diameter of 800 nm, the final equilibrium swelling ratio is 49.4 nm·nm-1, and the maximum resistance coefficient the blocking rate after swelling are 3.5 and 71.42%, respectively. The performance evaluation results show that nanoscale PMs can be used for in-depth profile control in the ultralow permeability oil reservoir. After the application of PMs in the pilot test area, the average water cut decreased by 10.4%, the average liquid production of single well-increased by 0.9 t/d, and the average thickness of the water-absorbing layer increased by 1.77 m. Comparing the dynamic data variation of well-groups using the PMs with the calibration diameter as 800 nm and the calibration diameter as 300 nm, it indicates that, for the pilot test area, PMs with a calibration diameter of 300 nm are more suitable than PMs with a calibration diameter of 800 nm.
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Osteoarthritis (OA) is a disorder of diarthrodial joints that can have multiple causes. Long non-coding RNAs (lncRNAs) participate in multiple diseases, including OA. It has recently been reported that the lncRNA microRNA 4435-2HG (MIR4435-2HG) is downregulated in OA tissues; however, the biological role of MIR4435-2HG during OA progression remains unclear. In the present study, interleukin (IL)-1ß was used to establish an in vitro model of OA. Protein expressions of matrix metallopeptidase (MMP) 1, MMP13, collagen II, interleukin (IL)-17A, p65, phosphorylated (p)-p65, IκB and p-IκB in CHON-001 cells were detected by western blotting. Gene expressions of IL-17A, MIR4435-2HG and miR-510-3p in tissues or CHON-001 cells were measured by reverse transcription-quantitative PCR and western blotting, respectively. Cell Counting Kit-8 assay and immunofluorescence staining were used to investigate cell proliferation, and cell apoptosis was detected by flow cytometry. The association between MIR4435-2HG, miR-510-3p and IL-17A was investigated using the dual luciferase report assay. MIR4435-2HG and miR-510-3p overexpression were transfected into CHON-001 cells. The results demonstrated that miR4435-2HG overexpression significantly increased proliferation and inhibited apoptosis of CHON-001 cells. In addition, miR-510-3p was identified as the downstream target of MIR4435-2HG, and miR-510-3p directly targeted IL-17A. The results from the present study suggested that MIR4435-2HG could mediate the progression of OA by inactivating the NF-κB signaling pathway. In addition, miR4435-2HG overexpression inhibited OA progression, suggesting that miR4435-2HG may be considered as a potential therapeutic target in OA.
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BACKGROUND: Osteosarcoma is the most prevalent malignant neoplasm in children and young adults with a very high propensity for local invasion and early systemic metastases. Radiotherapy has been widely used in metastatic and recurrent osteosarcoma, particularly with chemoresistance. METHODS: To determine whether autophagy is induced by radiation therapy and contributes to cell death of osteosarcoma, we investigated the influence of autophagy blockage on the radiosensitivity of osteosarcoma MG-63 cells in vitro. Firstly, autophagy in the MG-63 osteosarcoma cells after radiation treatment was determined by quantitative GFP-LC3 analysis and autophagy-related molecules analysis by western blotting. Then the viability and death of cells post-blockage of autophagy was determined by MTT assay and flow cytometry. RESULTS: It was demonstrated that autophagy was involved in MG-63 cells subject to radiation. Significantly up-regulated autophagic vesicles in MG-63 cells were subject to radiation. The transformation of LC-3 I to LC-3 II and the expression of autophagy-associated molecules were promoted in the radiation-treated MG-63 cells. Moreover, autophagy could ameliorate the cell viability post radiation. On the other hand, the chemical blockage of autophagy by 3MA not only could downregulate the level of autophagy, but also could reduce cell viability and accelerate apoptosis in the radiation-treated MG-63 cells. CONCLUSIONS: Autophagy was involved in the radiation treatment of MG-63 osteosarcoma cells, and autophagy blockage enhances the radiosensitivity of the osteosarcoma cell line MG-63 in vitro.
