Miscibility Characteristics of CO2-Oil in Tight Sandstone Reservoirs: Insights from Molecular Dynamics Simulations.

Identifying the microscopic mechanism of CO2-oil miscibility is significant for the CO2 enhanced oil recovery (CO2-EOR) in tight sandstone reservoirs. In this work, the effects of oil composition, formation pressure, temperature, and methane content on the characteristics of the CO2-oil miscibility were systematically studied by molecular simulation methods. According to the change of oil-gas centroid displacement, the CO2-oil miscibility behavior was divided into four stages: rapid diffusion, CO2 dissolution and oil swelling, competitive adsorption and oil film detachment, and complete miscibility or dynamic equilibrium stability. The results showed that light or medium component oil is more easily miscible with CO2 under reservoir conditions. The changes in temperature and pressure will greatly influence the oil-gas miscibility. Increasing the temperature is conducive to reducing the adsorption energy between oil and quartz, thus improving the miscibility of CO2 and heavy component oil. However, the static swelling effects of CO2 alone cannot effectively displace the heavy component oil on quartz. The CO2 diffusion coefficient perpendicular to the quartz surface does not increase continuously with the temperature increase due to the adsorption of oil and quartz. There is a critical temperature range of 320-340 K, which makes the miscibility effects the best. A small amount of CH4 can enhance the interaction energy between the two phases of oil and gas, thus promoting the miscibility of CO2 and oil at the interface. However, it is not conducive to oil film detachment, with the CH4 content increasing.

Efficacy and safety of vancomycin-loaded calcium sulfate versus conventional surgical debridement for pediatric acute osteomyelitis: a retrospective study.

BACKGROUND: The purpose of this study was to evaluate the safety and efficacy of vancomycin-loaded calcium sulfate beads and negative-pressure wound therapy (NPWT) in treating children with acute hematogenous osteomyelitis (AHOM). METHODS: A retrospective cohort study was conducted from January 2017 to January 2020 examining children (n = 60) with AHOM who were treated with surgical debridement followed by vancomycin-loaded calcium sulfate beads and NPWT (n = 32) and compared to treatment by conventional surgical debridement (n = 28) followed by NPWT. Conventional surgical treatment consisted of fenestration of necrotic infected bone, debridement of surrounding soft tissue, and washing of the medullary canal before the application of NPWT. In the vancomycin group, the antibiotic-loaded beads were implanted after washing the medullary canal and before the application of NPWT. Epidemiological factors, complications during the procedure, outcomes at last follow-up (30.0 ± 11.7 months, range 13-58 months), and laboratory parameters were documented and compared between the two groups. RESULTS: Good outcomes were achieved at last follow-up in 71.4% of the conventional treatment group and 75% of the vancomycin group. In the vancomycin group, it took a mean of 4.8 ± 2.5 days for CRP levels to decrease to 50% of initial inflammatory levels compared to 13 ± 9.6 days for the conventional treatment group (p = 0.001, t-test). The conventional group also had seven patients who underwent four or more surgeries whereas no patients in the vancomycin group underwent more than three surgeries (p = 0.013, chi-square test). CONCLUSION: Localized vancomycin delivery with NPWT effective for treating cases of AHOM that required. No perioperative adverse reactions or complications occurred from this treatment method. Based on the shortened recovery period of CRP levels, prolonged administration of post-operational parenteral antibiotics can possibly be reduced with this treatment method.

Six-Year Follow-Up of a Rare Bifid Talus and Eight-Toed Central Polydactyly: A Case Report.

Eight-toed central polydactyly is a rare congenital foot deformity and no other case with a bifid talus has been reported in the literature. We present a 6-year follow-up of a male child who had eight-toed central polydactyly with a duplicate cuneiform bone and bifid talus in his right foot. During preoperative planning, CT scans were conducted to evaluate the duplicate tarsals and to assist in reaching surgical decisions. In 2013, when the child was 1 year and 8 months old, the fourth, fifth and sixth phalanges and metatarsals as well as the duplicate cuneiform bone were excised. A portion of the malformed talus was also resected. This case report discusses functional and aesthetic outcomes after 6 years and provides an analysis on relevant reconstructive follow-up practices.

Bitter Taste Receptor as a Therapeutic Target in Orthopaedic Disorders.

Non-gustatory, extraoral bitter taste receptors (T2Rs) are G-protein coupled receptors that are expressed throughout the body and have various functional responses when stimulated by bitter agonists. Presently, T2Rs have been found to be expressed in osteoclasts and osteocytes where osteoclasts were capable of detecting bacterial quorum-sensing molecules through the T2R38 isoform. In the innate immune system, stimulating T2Rs induces anti-inflammatory and anti-pathogenic effects through the phospholipase C/inositol triphosphate pathway, which leads to intracellular calcium release from the endoplasmic reticulum. The immune cells with functional responses to T2R activation also play a role in bone inflammation and orthopaedic disorders. Furthermore, increasing intracellular calcium levels in bone cells through T2R activation can potentially influence bone formation and resorption. With recent studies finding T2R expression in bone cells, we examine the potential of targeting this receptor to treat bone inflammation and to promote bone anabolism.

The effect of mechanical stretch stress on the differentiation and apoptosis of human growth plate chondrocytes.

The study is aimed to investigate the effect of stretch stress with different intensities on the differentiation and apoptosis of human plate chondrocytes. In the present study, the human epiphyseal plate chondrocytes were isolated and cultured in vitro. Toluidine blue staining and type II collagen immunohistochemical staining were used to identify the chondrocytes. Mechanical stretch stresses with different intensities were applied to intervene cells at 0-, 2000-, and 4000-µ strain for 6 h via a four-point bending system. The expression levels of COL2, COL10, Bax, Bcl-2, and PTHrp were detected by quantitative RT-PCR. Under the intervention of 2000-µ strain, the expression levels of COL2, COL10, and PTHrp increased significantly compared with the control group (P < 0.05), and the expression level of PCNA was also increased, but the difference was not statistically significant (P > 0.05). Under 4000-µ strain, however, the expression levels of PCNA, COL2, and PTHrp decreased significantly compared with the control group (P < 0.05), and the expression level of COL10 decreased slightly (P > 0.05). The ratio of Bcl-2/Bax gradually increased with the increase of stimulus intensity; both of the differences were detected to be statistically significant (P < 0.05). In conclusion, the apoptosis of growth plate chondrocytes is regulated by mechanical stretch stress. Appropriate stretch stress can effectively promote the cells' proliferation and differentiation, while excessive stretch stress inhibits the cells' proliferation and differentiation, even promotes their apoptosis. PTHrp may play an important role in this process.

Ossotide promotes cell differentiation of human osteoblasts from osteogenesis imperfecta patients by up-regulating miR-145.

Ossotide as an effective bone formation compound preparation has been proved to promote osteoblasts differentiation. MiR-145 is significantly decreased in osteogenesis imperfecta (OI) patients, but it is still unknown whether ossotide performed its effect by regulating miR-145. In this study, we investigated the effect of ossotide on regulating miR-145 expression and osteoblasts differentiation. The primary osteoblasts cells were isolated from OI patients and then cultured with different concentrations (0, 25, 50, 100, 200µg/l) of ossotide. The cell proliferation was detected with CCK-8 Elisa kit after ossotide treatment. The level of miR-145 expression was determined using qRT-PCR. In order to study whether ossotide up regulated miR-145, miR-145 mimic and miR-145 inhibitor were used to up regulate and down regulate the miR-145 levels in osteoblasts. The expressions of Runx2, Osx, ß-catenin, TCF-1 were detected using Western blot and qRT-PCR. We observed that miR-145 was up regulated by ossotide treatment in miR-145 mimic or miR-145 inhibitor treated osteoblasts. What's more, up regulated miR-145 increased the expression of osteoblasts differentiation regulated protein Runx2 and Osx. In addition, Wnt signaling related ß-catenin, TCF-1 were activated by up-regulated miR-145 which was induced by ossotide treatment. In summary, ossotide induced cell differentiation and Wnt signaling activation in osteoblasts by up regulating miR-145.

[Treatment of severe displaced proximal humeral fractures with titanium elastic nails in older children].

OBJECTIVE: To evaluate the effectiveness of titanium elastic nails for severe displaced proximal humeral fractures in older children. METHODS: Between April 2009 and July 2012, 31 cases of severe displaced proximal humeral fractures were treated with closed or open reduction and fixation with 2 titanium elastic nails, and the clinical data were retrospectively analyzed. There were 23 boys and 8 girls, aged from 10 to 15 years (mean, 12.8 years). The causes of injury were sports injury (16 cases), traffic accident (11 cases), and falling from height (4 cases). The interval from injury to operation was 6 hours to 7 days (mean, 72 hours). According to Neer-Horwitz classification, 17 cases were rated as type III fracture and 14 cases as type IV fracture. There were 21 cases of metaphyseal fractures and 10 cases of epiphyseal fractures. RESULTS: Satisfactory reduction of fracture and stable fixation were obtained in all patients (closed reduction in 23 cases and open reduction in 8 cases). Primary healing was achieved in all incisions; no infection and neurovascular injury occurred. All patients were followed up 12-36 months with an average of 20 months. X-ray films showed that all fractures healed at 7-10 weeks (mean, 8 weeks). During follow-up, no disturbance of development or angulation deformity caused by premature physeal closure or bone bridge formation was observed. At last follow-up, the average Neer score of the shoulder was 95.7 (range, 83-100). The appearance and motion of the shoulder were normal. There was no significant difference in the upper extremity length between affected side and contralateral side [(67.68 +/- 2.56) cm vs. (67.61 +/- 2.54) cm; t = 1.867, P = 0.072]. CONCLUSION: Titanium elastic nails for severe displaced humeral fractures in older children is a safe and effective method with a low complication incidence.

[Cloning and expression of hemolytic-toxin from Actinobacillus pleuropneumoniae and the immunoprotection in mice].

The ApxIIA, ApxIIIA, ApxIVA genes from Actinobacillus pleuropneumoniae serotype 3 and the ApxIA gene from Actinobacillus pleuropneumoniae serotype 5 were respectively cloned into the prokaryotic expression vector pGEX-5X-3. Then the recombinant expression plasmids were respectively transformed into E. coli BL 21 and fusion protein expression were induced by IPTG. The expression products were purified by precipitation with ammonium sulfate and chromatography on Sephadex G-200. SDS-PAGE indicated that the productsexpressed at a high level when the recombinant E. coli BL21 was induced 2h, joining IPTG to final concentration 1 mmol/L. Western blot analysis showed that the expression products had immunogenicity and specificity. Subunit vaccines were made by different purified expression products and Freund's adjuvant. Mice were immunized at 30 days and 45 days with the subunit vaccines. Then the mice were challenged with the APP of serotype 1, 3, 5, 7 or 10 at 60 days. The result of animal immunoprotection test showed that subunit vaccines (ApxIA + ApxIVA, ApxIA + ApxIIIA + ApxIVA, ApxIA + ApxIIA + ApxIIIA + ApxIVA) could offer 58.4%, 66.6%, 91.7% protection in mice against the challenge of serotype 1, 5 and 7 APP, respectively. These results suggested that the recombinant proteins had good immunogenicity and the subunit vaccine containing four kind of recombinant proteins could induce better immunoprotection.