Dynamic Simulator for Three-Phase Gravity Separators in Oil Production Facilities.

In this study, a dynamic simulator for three-phase gravity separators in oil production facilities is proposed. The mass conservation equation is established to calculate the pressure, water level, and oil level in the separator and the mass balance equation of the dispersed phase to calculate the oil-water separation efficiency. The proportional integral controllers are applied to control the water level, oil level, and pressure in the separator by setting the opening of the three outlet valves of oil, gas, and water. The model is verified using field data by means of the given valve opening and given proportional integral controller parameters, respectively. Subsequently, the verified simulator is applied to study the dynamic behavior of the separator filling process and the effect of pressure, oil level, and water level setpoint changes on the separator operating status. A detailed analysis of the changes in the liquid level, pressure, and opening of three outlet valves is presented. Then, the effects of operating conditions such as the inlet flow, water setpoint, and weir height on the separation efficiency are discussed. This simulator can be applied for the design of oil, gas, and water three-phase separation processes. In addition, through this simulator, the parameters that are difficult to be measured by instruments during the operation of the separator can be calculated, providing technical support for the construction of the digital twin of the separator.

[Treatment of stable degenerative lumbar spondylolisthesis with percutaneous endoscopic surgery through two different approaches].

OBJECTIVE: To assess the clinical effects of percutaneous endoscopic surgery through two different approaches for stable degenerative lumbar spondylolisthesis. METHODS: Sixty-four patients with stable degenerative lumbar spondylolisthesis who underwent percutaneous endoscopic procedures between January 2016 and December 2019 were divided into transforaminal approach group and interlaminar approach group according to surgical approaches, 32 patients in each group. There were 16 males and 16 females in transforaminal approach group, aged from 52 to 84 years old with an average of (66.03±9.60) years, L2 slippage in 4 cases, L3 slippage in 5, and L4 slippage in 23. There were 17 males and 15 females in interlaminar approach group, aged from 46 to 81 years old with an average of (61.38±9.88) years, L3 slippage in 3 cases, L4 slippage in 15, and L5 slippage in 14. Operative time, intraoperative fluoroscopy times, and postoperative bedtime were compared between two groups. Anteroposterior displacement values, interbody opening angles, and the percentage of slippage were measured on preoperative and postoperative 12-month dynamic radiographs. Visual analogue scale (VAS) of low back pain and lower extremity pain, and the Japanese Orthopaedic Association (JOA) score before and after surgery were observed, and clinical effects were evaluated according to the modified MACNAB criteria. RESULTS: All operations were successfully completed, and patients in both groups were followed up for more than 1 year, and without complications during follow-up period. ①There was no significant difference in operation time between two groups(P>0.05). Intraoperative fluoroscopy times were longer in transforaminal approach group than that in intervertebral approach group(P<0.05). Postoperative bedtime was shorter in transforaminal approach group than that in intervertebral approach group (P<0.05).② No lumbar instability was found on dynamic radiography at 12 months postoperatively in both groups. There were no significant differences in anteroposterior displacement values, interbody opening angles, and the percentage of slippage between two groups postoperative 12 months and preoperative 1 day(P>0.05). ③There was no significant difference between two groups in VAS of low back pain at 3 days and 1, 12 months after the operation compared with the preoperative(P>0.05), but the VAS of the lower extremity pain was significantly improved compared with the preoperative(P<0.05). Both of groups showed significant improvement in JOA score at 12 months compared with preoperatively(P<0.05). There was no significant difference in VAS of low back pain, lower extremity pain and JOA scores between two groups during the same period after surgery(P>0.05). According to modified Macnab criteria, excellent, good, fair and poor outcomes were 21, 7, 3 and 1 in transforaminal approach group respectively, and which in intervertebral approach group were 20, 7, 5 and 0, there was no significant difference in clinical effect between the groups(P>0.05). CONCLUSION: Intervertebral approach may reduce intraoperative fluoroscopy times and transforaminal approach can shorten postoperative bedtime, both approaches achieve satisfactory results in the treatment of stable degenerative lumbar spondylolisthesis with no progression of short-term slippage.

Netrin-1 mediates nerve innervation and angiogenesis leading to discogenic pain.

Objective: Discogenic low back pain (LBP) is associated with nociceptive nerve fibers that grow into degenerated intervertebral discs (IVD) but the etiopathogenesis of disease is not fully understood. The purpose of this study was to clarify the role of Netrin-1 in causing discogenic LBP. Methods: The level of nociceptive nerve innervation was examined in disc degenerative patients and rat needle-punctured models by immunohistochemistry. Nucleus pulposus (NP) cells were isolated from IVD tissues of rats and induced degeneration by interleukin-1ß (IL-1ß) or tumor necrosis factor α (TNFα). The candidate genes related to neuron outgrowth and migration were selected by Next-generation sequencing (NGS). CRISPR/Cas9 was used to knockdown Netrin-1 in NP cells. The impact of Netrin-1 on nerve innervation were evaluated with P2X2、NF200 staining and microfluidics assay. Meanwhile the CD31 staining and transwell assay were used to evaluate the impact of Netrin-1 in angiogenesis. The proteins and RNA extracted from NP cells related to catabolism and anabolism were examined by western blot assay and RT-qPCR experiment. ChIP and luciferase experiments were used to assess the intracellular transcriptional regulation of Netrin-1. Further, a needle-punctured rat model followed by histomorphometry and immunofluorescence histochemistry was used to explore the potential effect of Netrin-1 on LBP in vivo. Results: The level of nerve innervation was increased in severe disc degenerative patients while the expression of Netrin-1 was upregulated. The supernatants of NP cells stimulated with IL-1ß or TNFα containing more Netrin-1 could promote axon growth and vascular endothelial cells migration. Knocking down Netrin-1 or overexpressing transcription factor TCF3 as a negative regulator of Netrin-1 attenuated this effect. The needle-punctured rat model brought significant spinal hypersensitivity, nerve innervation and angiogenesis, nevertheless knocking down Netrin-1 effectively prevented disc degeneration-induced adverse impacts. Conclusion: Discogenic LBP was induced by Netrin-1, which mediated nerve innervation and angiogenesis in disc degeneration. Knocking down Netrin-1 by CRISPR/Cas9 or negatively regulating Netrin1 by transcription factor TCF3 could alleviate spinal hypersensitivity. The translational potential of this article: This study on Netrin-1 could provide a new target and theoretical basis for the prevention and treatment for discogenic back pain.

MicroRNA-223-3p is involved in fracture healing by regulating fibroblast growth factor receptor 2.

MicroRNAs (miRNAs) are powerful modulators of fracture healing. The research explored the level of serum miR-223-3p in fracture patients and its potential mechanism in fracture healing. In the study, miR-223-3p levels in 42 patients with intra-articular fracture and 40 patients with hand fracture were detected by real-time fluorescence quantitative PCR reaction (qRT-PCR). Subsequently, osteoblasts MC3T3-E1 was transfected with miR-223-3p mimic or inhibitor, and cell function was detected by Cell counting kit (CCK-8) assay and flow cytometry. Dual-luciferase reporter assay verified the regulation mechanism of miR-223-3p and its target genes. We found that miR-223-3p was significantly elevated over time in patients with intra-articular fracture and hand fracture compared with healthy individuals. Moreover, increased miR-223-3p significantly reduced cell viability and promoted cell apoptosis. The fibroblast growth factor receptor 2 (FGFR2) was the target of miR-223-3p. Serum FGFR2 was significantly decreased in patients, which was contrary to the expression of miR-223-3p. Moreover, FGFR2 levels in cells were negatively regulated by miR-223-3p. Finally, si-FGFR2 significantly reversed the promotion of miR-223-3p inhibitor on cell viability and the inhibition of cell apoptosis. Our research suggested that miR-223-3p is highly expressed in fracture patients, and regulates osteoblast cell viability and apoptosis by targeting FGFR2. This may be a valuable target for fracture healing therapy and provide a new perspective for its treatment.

The biomechanical effect on the adjacent L4/L5 segment of S1 superior facet arthroplasty: a finite element analysis for the male spine.

BACKGROUND: The superior facet arthroplasty is important for intervertebral foramen microscopy. To our knowledge, there is no study about the postoperative biomechanics of adjacent L4/L5 segments after different methods of S1 superior facet arthroplasty. To evaluate the effect of S1 superior facet arthroplasty on lumbar range of motion and disc stress of adjacent segment (L4/L5) under the intervertebral foraminoplasty. METHODS: Eight finite element models (FEMs) of lumbosacral vertebrae (L4/S) had been established and validated. The S1 superior facet arthroplasty was simulated with different methods. Then, the models were imported into Nastran software after optimization; 500 N preload was imposed on the L4 superior endplate, and 10 N⋅m was given to simulate flexion, extension, lateral flexion and rotation. The range of motion (ROM) and intervertebral disc stress of the L4-L5 spine were recorded. RESULTS: The ROM and disc stress of L4/L5 increased with the increasing of the proportions of S1 superior facet arthroplasty. Compared with the normal model, the ROM of L4/L5 significantly increased in most directions of motion when S1 superior facet formed greater than 3/5 from the ventral to the dorsal or 2/5 from the apex to the base. The disc stress of L4/L5 significantly increased in most directions of motion when S1 superior facet formed greater than 3/5 from the ventral to the dorsal or 1/5 from the apex to the base. CONCLUSION: In this study, the ROM and disc stress of L4/L5 were affected by the unilateral S1 superior facet arthroplasty. It is suggested that the forming range from the ventral to the dorsal should be less than 3/5 of the S1 upper facet joint. It is not recommended to form from apex to base. LEVEL OF EVIDENCE: Level IV.

The biomechanical effects of graded upper articular process arthroplasty on lumbar spine: A finite element study.

BACKGROUND: Superior articular process arthroplasty is important for intervertebral foramen microscopy but may lead to spinal instability. Currently, there has been no relevant study in relation to the biomechanical analysis of superior articular process arthroplasty. Hence, this study is intended to verify biomechanical effects after unilateral S1 superior articular process arthroplasty. METHODS: Eight finite element (FE) models of lumbosacral vertebrae (L4-S) were constructed, and the superior articular process formation was simulated with the help of Geomagic studio. Then, the models were imported into Nastran software after optimization. Normal load and appropriate torque were applied to simulate forward flexion, back extension, lateral flexion and lateral rotation. In the end, changes of lumbar range of motion (ROM) and structural stress were compared with those of normal model. RESULTS: Compared with the normal model, formed from ventral to dorsal (Longitudinal), the larger motion of lumbar spine and the greater larger stress of articular process showed statistical significance (P < 0.05) in most of directions when the forming range was greater than 3/5. Formed from the apex to the base (transverse), the larger motion of lumbar spine and the greater stress of articular process showed statistical significance (P < 0.05) in most of directions when the forming range was great than 1/5. CONCLUSION: When conducting unilateral S1 articular process arthroplasty from ventral to dorsal, the forming range is recommended to be less than 3/5 of the superior articular process. Notably, it is not advisable to form from the apex to the base.

Discovery of a Highly Selective and Potent κ Opioid Receptor Agonist from N-Cyclopropylmethyl-7α-phenyl-6,14-endoethanotetrahydronorthebaines with Reduced Central Nervous System (CNS) Side Effects Navigated by the Message-Address Concept.

Effective and safe analgesics represent an unmet medical need for the treatment of acute and chronic pain. A series of N-cyclopropylmethyl-7α-phenyl-6,14-endoethanotetrahydronorthebaines were designed, synthesized, and assayed, leading to the discovery of a benzylamine derivative (compound 4, SLL-039) as a highly selective and potent κ opioid agonist (κ, Ki = 0.47 nM, κ/µ = 682, κ/δ = 283), which was confirmed by functional assays in vitro and antinociceptive assays in vivo. The in vivo effect could be blocked by pretreatment with the selective κ antagonist nor-BNI. Moreover, this compound did not induce sedation, a common dose limiting effect of κ opioid receptor agonists, at its analgesic dose compared to U50,488H. The dissociation of sedation/antinociception found in SLL-039 was assumed to be correlated with the occupation of its benzamide motif in a unique subsite involving V1182.63, W124EL1, and E209EL2.

Furowanin A Exhibits Antiproliferative and Pro-Apoptotic Activities by Targeting Sphingosine Kinase 1 in Osteosarcoma.

Osteosarcoma (OS) is one of the most common malignant bone tumors among children and young adults. Furowanin A (Fur A), one of the active ingredients of Millettia pachycarpa Benth, has been found to exert pro-apoptotic activity in human leukemia cells. This study is designed to evaluate the efficacy of Fur A against OS. The effect of Fur A on cell viability was assessed by Cell Counting Kit-8 (CCK-8) assay. Western blotting and quantitative real-time PCR (qRT-PCR) were performed to determine the protein and mRNA level of sphingosine kinase 1 (SphK1), respectively. To validate the role of SphK1 in the pro-apoptotic activity of Fur A, overexpressing SphK1 vector and siRNA targeting SphK1 were utilized to transfect OS cells. Moreover, an OS xenograft murine model was used to analyze the therapeutic efficacy of Fur A in vivo. Fur A treatment led to a dose-dependent decrease in the number of viable cells. It also exhibited antiproliferative activity and significantly promoted apoptotic cell death in OS cell lines. Our results showed that the anticancer activity of Fur A was associated with downregulation of SphK1 and inactivation of its downstream signaling. The mediatory role of SphK1 was validated when the pro-apoptotic activity of Fur A was significantly blocked by SphK1 overexpression, while SphK1 knockdown sensitized the OS cells to Fur A. We concluded that Fur A can exhibit anti-growth and pro-apoptotic activities in vitro and in vivo in OS by downregulating SphK1. Our study highlights the possibility of utilizing Fur A as a chemotherapeutic agent in the treatment of OS. Anat Rec, 302:1941-1949, 2019. © 2019 American Association for Anatomy.

7ß-Methyl substituent is a structural locus associated with activity cliff for nepenthone analogues.

With the purpose of identifying novel selective κ opioid receptor (KOR) antagonists as potential antidepressants from nepenthone analogues, starting from N-nor-N-cyclopropylmethyl-nepenthone (SLL-020ACP), a highly selective and potent KOR agonist, a series of 7ß-methyl-nepenthone analogues was conceived, synthesized and assayed on opioid receptors based on the concept of hybridization. According to the pharmacological results, the functional reversal observed in orvinol analogues by introduction of 7ß-methyl substituent could not be reproduced in nepenthone analogues. Alternatively, introduction of 7ß-methyl substituent was associated with substantial loss of both subtype selectivity and potency but not efficacy for nepenthone analogues, which was not found in 7ß-methyl orvinol analogues. Surprisingly, SLL-603, a 7ß-methyl analogue of SLL-020ACP, was identified to be a KOR full agonist. The possible molecular mechanism for the heterogeneity in activity cliff was also investigated. In conclusion, 7ß-methyl substituent was a structural locus associated with activity cliff and demonstrated as a pharmacological heterogeneity between nepenthone and orvinol analogues that warrants further investigations.

Down-regulated miR-448 relieves spinal cord ischemia/reperfusion injury by up-regulating SIRT1.

MicroRNAs play a crucial role in the progression of spinal cord ischemia/reperfusion injury (SCII). The role of miR-448 and SIRT1 in SCII was investigated in this study, to provide further insights into prevention and improvement of this disorder. In this study, expressions of miR-448 and SIRT1 protein were determined by qRT-PCR and western blot, respectively. Flow cytometry was used to analyze cell apoptosis. The endogenous expression of genes was modulated by recombinant plasmids and cell transfection. Dual-luciferase reporter assay was performed to determine the interaction between miR-448 and SIRT1. The Basso, Beattie, and Bresnahan score was used to measure the hind-limb function of rat. The spinal cord ischemia reperfusion injury model of adult rats was developed by abdominal aorta clamping, and the nerve function evaluation was completed by motor deficit index score. In SCII tissues and cells treated with hypoxia, miR-448 was up-regulated while SIRT1 was down-regulated. Hypoxia treatment reduced the expression of SIRT1 through up-regulating miR-448 in nerve cells. Up-regulation of miR-448 induced by hypoxia promoted apoptosis of nerve cells through down-regulating SIRT1. Down-regulated miR-448 improved neurological function and hind-limb motor function of rats with SCII by up-regulating SIRT1. Down-regulated miR-448 inhibited apoptosis of nerve cells and improved neurological function by up-regulating SIRT1, which contributes to relieving SCII.

[Biomechanical study of the stability of subaxial cervical anterior transpedicular screw fixation for three-column injury].

OBJECTIVE: To compare the stability of subaxial cervical anterior transpedicular screw(ATPS) fixation and three traditional fixations for three-column injury. METHODS: Six specimens of cervical spine were prepared. After measurememt of the range of motion(ROM) in intact state, the specimens were made into three-column injury models. The models were reconstructed with an anterior cervical cage, and stabilized by ATPS, anterior plate(AP), anterior plate + lateral mass screw(AP+LMS) and posterior transpedicular screw(PTPS). The ROM of the models in the four states were measured, and the results of data were compared after standardization. RESULTS: The normalized ROM of ATPS state in flexion-extension, lateral bending, axial rotation were(77.17±4.75)%, (82.00±2.61)%, (83.17±2.23)%, which were significant small than those in intact state(P<0.05). The normalized ROM of AP state in flexion-extension, lateral bending, axial rotation were(119.67±7.42)%, (116.33±7.53)%, (112.67±5.99)% , which were significant larger than those in intact state(P<0.05). The normalized ROM of AP in all directions were significant larger than those of ATPS(P<0.05). There was no significant difference between normalized ROM of PTPS state and those of ATPS state in flexion-extension and lateral bending(P>0.05). The normalized ROM of PTPS state in axial rotation was(6.83±2.48)% and was significant larger than that of ATPS state(P=0.009). The normalized ROM of AP+LMS state in flexion-extension was(68.50±2.43)%, which was significant smaller than that of ATPS state(P=0.003). There was no significant difference between the normalized ROM of AP+LMS state and those of ATPS state in lateral bending and axial rotation(P>0.05). CONCLUSIONS: Subaxial cervical three-column injury model reconstruction by ATPS can provide the adequate primary stability, of which biomechanics property is superior compared to AP and PTPS, and is similar to that of AP+LMS. It can be applied to the patients with no need to decompression and reduction through posterior approach.

Stability of two anterior fixations for three-column injury in the lower cervical spine: biomechanical evaluation of anterior pedicle screw-plate fixation.

Objectives This study aimed to evaluate the stability of anterior pedicle screw-plate (APSP) fixation and anterior vertebral body screw-plate (AVBSP) fixation for three-column injury in the lower cervical spine. Methods Six fresh-frozen human cadaveric specimens of the lower cervical spine were prepared. After measurement of the range of motion (ROM) in the intact state, the specimens were prepared as three-column injury models. The models were stabilized by AVBSP or APSP fixation. The ROM of the models in the two states was measured. The ROM in the two states was compared. Results The ROM of the intact state in all directions was significantly smaller than that of the AVBSP state and significantly larger than that of the APSP state. The ROM of the AVBSP state in all directions was significantly larger than that of the APSP state. Conclusions This study shows that APSP fixation can provide sufficient stability for three-column injury in the lower cervical spine. The primary stability of our models using APSP fixation is superior to that of AVBSP fixation. These results suggest that APSP can be used for three-column injury in the lower cervical spine.

Hydrate slurry flow property in W/O emulsion systems.

Hydrate risk management strategy has become a promising way of dealing with hydrates in subsea transportation pipelines in recent years. In this way, hydrates are allowed to form in the pipeline and are treated as a slurry flow with the help of anti-agglomerants. This work investigated the effect of hydrate formation on the flow friction factor in water in oil (W/O) emulsion systems. A series of hydrate formation and slurry flow experiments were conducted using a high pressure flow loop. Results show that the friction factor is in direct proportion to the volume fraction of hydrates formed, as it increases significantly after hydrate formation onset and then increases gradually with hydrate growing. A novel method is proposed in this work to amend the effective hydrate volume fraction and take into account the effect of hydrate agglomeration and water occlusion. In addition, it is found that the slurry flow velocity has a significant effect on the friction factor variation. As a larger flow velocity can lift the particles suspension height and cause the particles to be away from the pipe wall surface, so it gives a smaller friction factor by reducing the collisions between hydrate particles and the pipe wall surface. With the modified effective hydrate volume fraction and particle chord length distribution data, a model is proposed to estimate the hydrate caused friction factor in W/O emulsion systems, which shows a good prediction accuracy in 10% and 20% water cut conditions.

Down-regulated miR-448 relieves spinal cord ischemia/reperfusion injury by up-regulating SIRT1

MicroRNAs play a crucial role in the progression of spinal cord ischemia/reperfusion injury (SCII). The role of miR-448 and SIRT1 in SCII was investigated in this study, to provide further insights into prevention and improvement of this disorder. In this study, expressions of miR-448 and SIRT1 protein were determined by qRT-PCR and western blot, respectively. Flow cytometry was used to analyze cell apoptosis. The endogenous expression of genes was modulated by recombinant plasmids and cell transfection. Dual-luciferase reporter assay was performed to determine the interaction between miR-448 and SIRT1. The Basso, Beattie, and Bresnahan score was used to measure the hind-limb function of rat. The spinal cord ischemia reperfusion injury model of adult rats was developed by abdominal aorta clamping, and the nerve function evaluation was completed by motor deficit index score. In SCII tissues and cells treated with hypoxia, miR-448 was up-regulated while SIRT1 was down-regulated. Hypoxia treatment reduced the expression of SIRT1 through up-regulating miR-448 in nerve cells. Up-regulation of miR-448 induced by hypoxia promoted apoptosis of nerve cells through down-regulating SIRT1. Down-regulated miR-448 improved neurological function and hind-limb motor function of rats with SCII by up-regulating SIRT1. Down-regulated miR-448 inhibited apoptosis of nerve cells and improved neurological function by up-regulating SIRT1, which contributes to relieving SCII.

[Percutaneous endoscopic lumbar discectomy combined with epidural injection for prolapsed lumbar disc herniation].

OBJECTIVE: To assess the effect of percutaneous endoscopic lumbar discectomy (PELD) combined with epidural injection for prolapsed lumbar disc herniation(PLDH). METHODS: In this prospective randomized controlled study, the clinical data of 126 patients who had undergone a PELD because of a single-level PLDH from March 2014 to June 2015 were analyzed. There were 67 males and 59 females, ranging in age from 17 to 75 years old with an average of(41.0±13.5) years old, 9 cases were L3,4, 76 cases were L4,5 and 41 cases were L5S1. According to the random number table, the patients were randomized into two groups, with 63 patients in each group. Patients in group 1 were injected normal saline after PLED, patients in group 2 were subjected to an epidural injection of Diprospan, Lidocaine and Mecobalamine after PLED. All the patients were followed up from 6 to 20 months with the mean of 12.4 months. Complications, the postoperative hospital stay, the period of return to work, visual analogue scale (VAS) and Japanese Orthopedic Association (JOA) score were compared between two groups, and clinical outcomes were evaluated according to modified MacNab criteria. RESULTS: All the operations were successful, and no complications were found. The mean postoperative hospital stay and the period of return to work in group 1 were (4.61±1.25) days and (4.31±0.47) weeks, respectively, and in group 2 were (2.53±0.69) days and (3.14±0.52) weeks, there was significant differences between two groups(P=0.000). Postoperative VAS and JOA scores in two groups were obviously improved (P=0.000). At 1 day, 1 week, 1 month after operation, VAS, JOA scores in group 2 were better than that of group 1(P=0.000), and after 6 months, there was no significant difference between two groups(P>0.05). According to the modified MacNab criteria, 39 cases got excellent results, 21 good, 3 fair in group 1, and which in group 2 were 41, 20, 2, respectively, there was no significant difference between two groups(P=0.087). CONCLUSIONS: PELD is an mini-invasive technique for PLDH, it can fleetly reduce pain and improve function. And combination with epidural injection has the advantages of pain releasing and function improving in the short-term postoperative period, and it can decrease postoperative hospital stay and time of returning to work, and it is a safe and effective method.