Magnesium Oxychloride and Magnesium Oxysulfate Cements as Temporary Plugging Agents in Geothermal Drilling.

The development and utilization of geothermal resources are effective ways to alleviate the current haze situation, adjust the energy structure, and achieve energy conservation and emission reduction. Geothermal formations typically contain extensive fracture networks, with fracture openings. These fracture networks can result in substantial losses of the drilling fluid and increased costs for geothermal drilling. Temporary plugging cements are used to solve the problem of lost circulation due to their high strength and high acid solubility. In this paper, two types of temporary plugging materials, magnesium oxysulfate (MOS) cement and magnesium oxychloride (MOC) cement, were prepared. The influence of the plugging agent on the flow field and the force exerted on the solid under the action of the fluid was analyzed using fluid-solid coupling software. The simulation results show that when subjected to a flow rate of 10 m/s, the edge of the cement experiences a significant force, while the stress is not widely transmitted to the middle and rear of the cement. This indicates that the cement has a strong resistance to the fluid flow. The fundamental characteristics of MOC cement and MOS cement, such as compressive strength and setting time, were investigated. The test results show that adjusting the molar ratio of the two types of cements can shorten the setting time by 60% and increase the compressive strength to up to 23 MPa. In addition, the acid solubility of the cement with different ratios of raw materials is above 95%. The plugging performance of these two cements as loss circulation materials was evaluated by using a physical simulation device. The pressure bearing capacity of the MOC cement with different MgO/MgCl2·6H2O/H2O molar ratios ranged between 13.4 and 23.6 MPa. The maximum bearing capacity of the MOS cement can reach up to 18.6 MPa. The results showed that both cements possess excellent plugging and pressure bearing capacity.

Preparation and Foam Stabilization Mechanism of an Ultrahigh-Temperature Colloidal Gas Aphron (CGA) System Based on Nano-SiO2.

Recently, colloidal gas aphron (CGA) drilling fluids have successfully solved the problem of drilling low-pressure depleted oil and gas reservoirs. However, with the increase in the drilling depth and the development of geothermal resources, high-temperature stable CGA drilling fluids need to be developed urgently. This research reports a highly stable nano-SiO2-based CGA system with a temperature resistance of 200 °C. Waring-Blender tests show that 1.5-3% nano-SiO2 greatly improves the high-temperature stability of the CGA system, and the half-life of foam aged at 120-200 °C can reach 6-12 h. Also, the nano-SiO2-based CGA system aged at 200 °C can maintain an independent and stable morphology during the observation period (60 min), and there is no obvious drainage and merger in the system. The stabilizing mechanism of nano-SiO2 has been revealed, which can be summarized as the comprehensive effect of adsorption, viscosity increase, and cross-linking. In other words, the addition of nano-SiO2 enhanced steric hindrance and liquid film strength by reducing the surface tension, increasing fluid viscosity, and forming a network-like structure.

Lysine Deprivation Suppresses Adipogenesis in 3T3-L1 Cells: A Transcriptome Analysis.

Growing evidence proves that amino acid restriction can reverse obesity by reducing adipose tissue mass. Amino acids are not only the building blocks of proteins but also serve as signaling molecules in multiple biological pathways. The study of adipocytes' response to amino acid level changes is crucial. It has been reported that a low concentration of lysine suppresses lipid accumulation and transcription of several adipogenic genes in 3T3-L1 preadipocytes. However, the detailed lysine-deprivation-induced cellular transcriptomic changes and the altered pathways have yet to be fully studied. Here, using 3T3-L1 cells, we performed RNA sequencing on undifferentiated and differentiated cells, and differentiated cells under a lysine-free environment, and the data were subjected to KEGG enrichment. We found that the differentiation process of 3T3-L1 cells to adipocytes required the large-scale upregulation of metabolic pathways, mainly on the mitochondrial TCA cycle, oxidative phosphorylation, and downregulation of the lysosomal pathway. Single amino acid lysine depletion suppressed differentiation dose dependently. It disrupted the metabolism of cellular amino acids, which could be partially reflected in the changes in amino acid levels in the culture medium. It inhibited the mitochondria respiratory chain and upregulated the lysosomal pathway, which are essential for adipocyte differentiation. We also noticed that cellular interleukin 6 (IL6) expression and medium IL6 level were dramatically increased, which was one of the targets for suppressing adipogenesis induced by lysine depletion. Moreover, we showed that the depletion of some essential amino acids such as methionine and cystine could induce similar phenomena. This suggests that individual amino acid deprivation may share some common pathways. This descriptive study dissects the pathways for adipogenesis and how the cellular transcriptome was altered under lysine depletion.

Effect of plan-do-check-active method combined with air pressure wave therapy on the prevention of deep venous thrombosis in critically ill patients in neurosurgery.

BACKGROUND: Deep vein thrombosis (DVT) is prone to occur in the recovery of critically ill neurosurgical patients, increasing economic and psychological pressure, and even endangering life. Plan-Do-Check-Action (PDCA) cycle is a kind of quality management cycle procedure, which can help DVT treatment correctly understand the cause of disease and take effective preventive and nursing measures. The air wave pressure therapy instrument takes pressure therapy as the core, forming circulating pressure on limbs and tissues, promoting the flow of blood and lymph, improving the effect of microcirculation, accelerating the return of limb tissue fluid, and preventing thrombosis and limb edema. METHODS: A total of 98 critical neurosurgery patients were selected as the study subjects. On the basis of PDCA circulation treatment, the patients were treated with air pressure wave for 30 minutes/time, twice/day and 14 days. Before and after treatment, the indexes of coagulation function, hemorheology (plasma viscosity, whole blood high shear viscosity and whole blood low shear viscosity), lower limb circumference (15 cm above and below the patella) and Barthel index (BI) scores were observed and recorded. DVT was observed by vascular Doppler ultrasound before and after treatment, and the incidence was calculated. RESULTS: The prothrombin time (18.09 s) and thrombin time (17.66 s) after treatment were higher than those before treatment (12.98 s, 130.7 s), and fibrinogen decreased (4.21 vs. 3.31 g/L). The hemorheological indexes of the patients after treatment were plasma viscosity (1.49 mPa/s, 10.8 mPa/s), whole blood high shear viscosity (6.34 mPa/s, 4.47 mPa/s), whole blood low shear viscosity (9.89 mPa/s, 6.32 mPa/s), circumference at 15 cm below the patella (52.29 cm, 45.23 cm), and circumference at 15 cm above the patella (36.17 cm, 31.38 cm). The BI score showed that the number of patients with severe dependence on grade A (46/15) and moderate dependence on grade B (50/14) decreased after treatment, and the average BI score of patients with combined treatment increased (43.87 and 79.86). After treatment, the number of patients with DVT (20/4) and the incidence of DVT (20.40816327%, 4.081632653%) decreased significantly (P<0.05). CONCLUSIONS: PDCA circulation combined with barometric wave therapy can significantly improve DVT in critical neurosurgical patients.

Biodegradable Lubricant with High-Temperature and Ionic-Contamination Resistance: Deep Eutectic Solvent ChCl-PEG.

Drilling fluid lubricants guarantee safe and fast drilling. When drilling high-temperature or NaCl/CaCl2-containing formations, there is an urgent need to develop environmentally friendly lubricants that are resistant to high temperature and ionic contamination. In this study, a deep eutectic solvent (DES) ChCl-PEG lubricant for a water-based drilling fluid was designed and prepared. ChCl-PEG is a kind of biodegradable material with high thermal stability formed by hydrogen bonding between choline chloride (ChCl) and polyethylene glycol (PEG). Within 240 °C, ChCl-PEG significantly improved the lubricating properties of drilling fluids and mud cakes. The lubrication coefficient (K) was controlled within 0.2, and the reduction rate of the adhesion coefficient (Δf) was higher than 40%. The salt and calcium resistances of ChCl-PEG at high temperature (150 °C) are as high as 36% NaCl and 20% CaCl2. Under these conditions, ChCl-PEG maintains a low value of K: 0.097-0.157 (5-36% NaCl) and 0.145-0.162 (5-20% CaCl2), respectively. Also, it maintains higher values of Δf, which can reach up to 51.6% and 80%. The lubricating mechanism of ChCl-PEG can be summarized as the adsorption of ChCl and the formation of a large number of hydrated molecules.

Effective Modified Xanthan Gum Fluid Loss Agent for High-Temperature Water-Based Drilling Fluid and the Filtration Control Mechanism.

Xanthan gum (XG) was widely used as an oilfield chemical treatment agent because of its environmental protection and diverse functions. With the increased drilling depth and formation complexity, the shortcomings such as poor solubility and low resistance to temperature were gradually exposed. In this study, a modified XG derivative XG-g-AAA was synthesized by grafting XG with acrylic acid (AA), acrylamide (AM), and 2-acrylamido-2-methylpropane sulfonic acid (AMPS). The chemical structure of XG-g-AAA was determined by Fourier transform infrared spectroscopy and nuclear magnetic resonance (1H NMR). Then, the solubility, high-temperature rheology and filtration properties, resistance to Na+/Ca2+, and compatibility were investigated. Results show that (1) both in aqueous and salt solutions, XG-g-AAA can completely be dissolved within 15 min. The significant improvement of the solubility of XG-g-AAA makes it more suitable for field use. (2) XG-g-AAA is less sensitive to high temperatures, and the viscosity decay decreased by 23.3 and 21.3% than XG at 150 and 180 °C, respectively. XG-g-AAA-based drilling fluid is a high-quality drilling fluid with significant shear thinning behavior, and the power-law model is the optimal model to describe its high-temperature rheology. Within 150 °C, 1.5% XG-g-AAA can maintain a reasonable value of the flow behavior index (n) (0.55-0.69), filtration volume (<11.6 mL), and sufficient gel strength (GS). At 150-200 °C, 3% XG-g-AAA is recommended. The value of n was in the range of 0.45-0.62, and the fluid loss was within 10 mL. However, 3% XG-g-AAA cannot provide enough GS at 200 °C; thus, a shear strength-improving agent is recommended to be added. (3) XG-g-AAA showed excellent contamination tolerance and compatibility. It could resist 2 wt % CaCl2 and 35 wt % NaCl at room temperature and 0.75% CaCl2 and 5% NaCl after 150 °C aging. (4) XG-g-AAA showed compatibility with sulfonated drilling fluids and could replace commercial fluid loss agents in the formula. Furthermore, the high-temperature fluid loss control mechanism was discussed by analyzing the effects of XG-g-AAA on the bentonite layer spacing, particle size distribution, stability of the colloidal system, and mud cakes.

Effect of inorganic salt on partition of high-polarity parishins in two-phase solvent systems and separation by high-speed counter-current chromatography from Gastrodia elata Blume.

Parishins are high-polarity and major bioactive constituents in Gastrodia elata Blume. In this study, the effect of several inorganic salts on the partition of parishins in two-phase solvent systems was investigated. Adding ammonium sulfate, which has a higher solubility in water, was found to significantly promote the partition of parishins in the upper organic polar solvents. Based on the results, a two-phase solvent system composed of butyl alcohol/acetonitrile/near-saturated ammonium sulfate solution/water (1.5:0.5:1.2:1, v/v/v/v) was used for the purification of parishins by high-speed counter-current chromatography. Fractions obtained from high-speed counter-current chromatography were subjected to semi-preparative high-performance liquid chromatography to remove salt and impurities. As a result, parishin E (6.0 mg), parishin B (7.8 mg), parishin C (3.2 mg), gastrodin (15.3 mg), and parishin A (7.3 mg) were isolated from water extract of Gastrodia elata Blume (400 mg). These results demonstrated that adding inorganic salt that has high solubility in water to the two-phase solvent system in high-speed counter-current chromatography was a suitable approach for the purification of high-polarity compounds.

Design, synthesis, antitumor evaluations and molecular modeling studies of novel 3,5-substituted indolin-2-one derivatives.

AIM: To design and synthesize a novel class of antitumor agents, featuring the 3, 5-substituted indolin-2-one framework. METHODS: Based on enzyme binding features of (Z)-SU5402, introducing a beta-pyrrole group at the 3-position of the indolin- 2-one core, a series of novel 3,5-substituted indolin-2-ones were designed and synthesized. Four human carcinoma cell lines of A-431, A-549, MDA-MB-468, and Autosomal Dominant Polycystic Kidney disease were chosen for the cell proliferation assay. RESULTS: Twenty new compounds (1a-t) with E configuration have been designed, synthesized and bioassayed. Their structural features were determined by nuclear magnetic resonance (NMR) spectra, low- and high-resolution mass spectra, and confirmed by X-ray crystallography. Although the enzyme assay showed a weak inhibition effect against the epidermal growth factor receptor, vascular endothelial growth factor receptor, fibroblast growth factor receptor and platelet-derived growth factor receptor tyrosine kinases, the cell-based antitumor activity was promising. Compounds 1 g and 1 h showed higher inhibitory activity toward the A-549 and MDA-MB-468 cell lines with IC(50 ) of 0.065-9.4 micromol/L. CONCLUSION: This study provides a new template for further development of potent antitumor drugs.