Precessing jet nozzle connecting to a spinning black hole in M87.

The nearby radio galaxy M87 offers a unique opportunity to explore the connections between the central supermassive black hole and relativistic jets. Previous studies of the inner region of M87 revealed a wide opening angle for the jet originating near the black hole1-4. The Event Horizon Telescope resolved the central radio source and found an asymmetric ring structure consistent with expectations from general relativity5. With a baseline of 17 years of observations, there was a shift in the jet's transverse position, possibly arising from an 8- to 10-year quasi-periodicity3. However, the origin of this sideways shift remains unclear. Here we report an analysis of radio observations over 22 years that suggests a period of about 11 years for the variation in the position angle of the jet. We infer that we are seeing a spinning black hole that induces the Lense-Thirring precession of a misaligned accretion disk. Similar jet precession may commonly occur in other active galactic nuclei but has been challenging to detect owing to the small magnitude and long period of the variation.

A ring-like accretion structure in M87 connecting its black hole and jet.

The nearby radio galaxy M87 is a prime target for studying black hole accretion and jet formation1,2. Event Horizon Telescope observations of M87 in 2017, at a wavelength of 1.3 mm, revealed a ring-like structure, which was interpreted as gravitationally lensed emission around a central black hole3. Here we report images of M87 obtained in 2018, at a wavelength of 3.5 mm, showing that the compact radio core is spatially resolved. High-resolution imaging shows a ring-like structure of [Formula: see text] Schwarzschild radii in diameter, approximately 50% larger than that seen at 1.3 mm. The outer edge at 3.5 mm is also larger than that at 1.3 mm. This larger and thicker ring indicates a substantial contribution from the accretion flow with absorption effects, in addition to the gravitationally lensed ring-like emission. The images show that the edge-brightened jet connects to the accretion flow of the black hole. Close to the black hole, the emission profile of the jet-launching region is wider than the expected profile of a black-hole-driven jet, suggesting the possible presence of a wind associated with the accretion flow.

Understanding Synergistic Catalysis on Cu-Se Dual Atom Sites via Operando X-ray Absorption Spectroscopy in Oxygen Reduction Reaction.

The construction and understanding of synergy in well-defined dual-atom active sites is an available avenue to promote multistep tandem catalytic reactions. Herein, we construct a dual-hetero-atom catalyst that comprises adjacent Cu-N4 and Se-C3 active sites for efficient oxygen reduction reaction (ORR) activity. Operando X-ray absorption spectroscopy coupled with theoretical calculations provide in-depth insights into this dual-atom synergy mechanism for ORR under realistic device operation conditions. The heteroatom Se modulator can efficiently polarize the charge distribution around symmetrical Cu-N4 moieties, and serve as synergistic site to facilitate the second oxygen reduction step simultaneously, in which the key OOH*-(Cu1 -N4 ) transforms to O*-(Se1 -C2 ) intermediate on the dual-atom sites. Therefore, this designed catalyst achieves satisfied alkaline ORR activity with a half-wave potential of 0.905 V vs. RHE and a maximum power density of 206.5 mW cm-2 in Zn-air battery.

Opening-Wedge High Tibial Osteotomy Using Autograft versus Allograft: A Systematic Review and Meta-analysis.

Bone grafting is a good alternative for filling the inevitable void that is created following opening-wedge high tibial osteotomy (OWHTO). This systematic review and meta-analysis evaluated whether bone grafting is necessary for OWHTO and the successful outcomes of OWHTO using either autograft (AU) or allograft (AL). All analyzed studies were acquired from PubMed, Medline, Embase, CNKI, Google Scholar, and Cochrane Library. Data were independently extracted by two coauthors and were analyzed using RevMan5.3. Mean differences, odds ratios, and 95% confidence intervals were calculated. Cochrane Collaboration's Risk of Bias Tool and Newcastle-Ottawa Scale were used to assess the risk of bias. In total, 10 studies were assessed including three randomized controlled trials and seven observational studies. The methodological quality of the trials ranged from low to high. The overall estimate demonstrated that the difference between OWHTO using AU and AL groups and OWHTO using no filling group was not statistically significant for the loss of correction, and complications, but OWHTO using no filling group statistically showed better knee society score. Pooled results of reoperations, lateral cortex breaches, complications, and clinical function assessments showed no significant difference between AU and AL materials. Using AL statistically reduced the operative time compared with using AU. OWHTO with or without bone graft does not affect postoperative complications. No loss of correction was observed due to the lack of bone grafting. In addition, OWHTO without bone graft performs better for postoperative clinical function assessment. Complications and clinical results of medial OWHTO were similar using AL and AU and neither reported a median loss of correction of following OWHTO. Compared with using AU, using AL avoids harvest site complications and reduces operative time. To sum up, OWHTO without any bone graft is recommended for medial unicompartmental osteoarthritis of the knee. Further large-sample, multicenter, high-quality, randomized controlled trials are warranted to verify the outcomes of this meta-analysis.

Exercise interventions for ankylosing spondylitis: a protocol for a Bayesian network meta-analysis.

INTRODUCTION: Ankylosing spondylitis (AS) is a universal chronic inflammatory rheumatic disease which predominantly results in chronic back pain and stiffness. However, some patients suffering from AS do not react well to pharmacological interventions. Exercise intervention has been employed for the treatment of AS and works as a complementary part of the management of AS. However, the effect of different types of exercise interventions remains unclear. The purpose of this study is to determine the relative efficacy of different types of exercise interventions for individuals with AS using a Bayesian network meta-analysis. METHODS AND ANALYSIS: We will conduct a systematic literature review of randomised controlled trials that compare different types of exercise interventions for individuals with AS. PubMed, EMBASE and the Cochrane Library will be searched up to February 2019. The primary outcomes are functional capacity, pain and disease activity. The risk of bias for individual studies will be evaluated according to the Cochrane Handbook. A Bayesian network meta-analysis will be performed to compare the efficacy of different types of exercise interventions. The quality of evidence will be assessed by the Grading of Recommendations, Assessment, Development and Evaluation approach. ETHICS AND DISSEMINATION: Ethical approval and patient consent are not required as this study is a meta-analysis based on published studies. The results of this network meta-analysis will be submitted to a peer-reviewed journal for publication. PROSPERO REGISTRATION NUMBER: CRD42019123099.

Bone marrow mesenchymal stem cells stimulated with low-intensity pulsed ultrasound: Better choice of transplantation treatment for spinal cord injury: Treatment for SCI by LIPUS-BMSCs transplantation.

Stem cell transplantation, especially treatment with bone marrow mesenchymal stem cells (BMSCs), has been considered a promising therapy for the locomotor and neurological recovery of spinal cord injury (SCI) patients. However, the clinical benefits of BMSCs transplantation remain limited because of the considerably low viability and inhibitory microenvironment. In our research, low-intensity pulsed ultrasound (LIPUS), which has been widely applied to clinical applications and fundamental research, was employed to improve the properties of BMSCs. The most suitable intensity of LIPUS stimulation was determined. Furthermore, the optimized BMSCs were transplanted into the epicenter of injured spinal cord in rats, which were randomized into four groups: (a) Sham group (n = 10), rats received laminectomy only and the spinal cord remained intact. (b) Injury group (n = 10), rats with contused spinal cord subjected to the microinjection of PBS solution. (c) BMSCs transplantation group (n = 10), rats with contused spinal cord were injected with BMSCs without any priming. (d) LIPUS-BMSCs transplantation group (n = 10), BMSCs stimulated with LIPUS were injected at the injured epicenter after contusion. Rats were then subjected to behavioral tests, immunohistochemistry, and histological observation. It was found that BMSCs stimulated with LIPUS obtained higher cell viability, migration, and neurotrophic factors expression in vitro. The rate of apoptosis remained constant. After transplantation of BMSCs and LIPUS-BMSCs postinjury, locomotor function was significantly improved in LIPUS-BMSCs transplantation group with higher level of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in the epicenter, and the expression of neurotrophic receptor was also enhanced. Histological observation demonstrated reduced cavity formation in LIPUS-BMSCs transplantation group when comparing with other groups. The results suggested LIPUS can improve BMSCs viability and neurotrophic factors expression in vitro, and transplantation of LIPUS-BMSCs could promote better functional recovery, indicating possible clinical application for the treatment of SCI.

Thoracic aggressive vertebral hemangioma with neurologic deficit: A retrospective cohort study.

The aim of this study is to evaluate the safety and effectiveness in the treatment of thoracic aggressive vertebral hemangiomas (AVHs) with neurologic deficit by multiple surgical treatments.The clinical and radiographic data of 5 patients suffering from thoracic AVHs with neurologic deficit and treated by multiple surgical treatments, including percutaneous curved vertebroplasty (PCVP) combined with pedicle screw fixation and decompressive laminectomy, were reviewed and analyzed retrospectively.Five patients (3 women and 2 man, with a mean age of 57.40 ±â€Š11.93) were diagnosed with AVHs from July 2010 to April 2016. All of them had objective neurologic deficit, myelopathy, and back pain. They underwent multiple surgical treatments and were followed-up for 12 to 23 months. At final follow-up, Frankel Grade D was achieved in all 5 patients. Patients were free from pain and neurologic symptoms, and the functional status was improved. No major complication was found.The treatment of AVHs with neurologic deficit is a challenge for surgeons. PCVP combined with pedicle screw fixation and decompressive laminectomy is safe and effective, and can be used for AVHs with neurologic deficit. Further studies with more samples are required to validate the effectiveness and safety of PCVP combined with pedicle screw fixation and decompressive laminectomy.

Secondary Surgery after Cervical Disc Arthroplasty versus Fusion for Cervical Degenerative Disc Disease: A Meta-analysis with Trial Sequential Analysis.

The purpose of this meta-analysis was to explore whether cervical disc arthroplasty (CDA) was superior to anterior cervical discectomy and fusion (ACDF) in reducing secondary surgery. PubMed, EMBASE, and the Cochrane Library databases were systematically searched. Outcomes were reported as relative risk (RR) with the corresponding 95% confidence interval (CI). The pooled data was calculated using a random-effect model. We also used the trial sequential analysis (TSA) to further verify our results and obtain more moderate estimates. Twenty-one studies with 4208 patients were included in this meta-analysis. The results indicated that compared with ACDF, CDA had fewer frequency of secondary surgery at the index level (RR, 0.47; 95%CI, 0.36-0.63; P < 0.05) and adjacent level (RR, 0.48; 95%CI, 0.36-0.65; P < 0.05), and the differences were statistically significant. In addition, in terms of the overall frequency of secondary surgery at the index and adjacent level, CDA was also significantly superior to ACDF (RR, 0.49; 95%CI, 0.41-0.60; P < 0.05). TSA demonstrated that adequate and decisive evidence had been established. Regarding the frequency of secondary surgery, CDA was significantly superior to ACDF. It was supposed that CDA may be a better surgical intervention to reduce the rate of secondary surgery for patients with cervical degenerative disc disease.

Comparison of Mobi-C Cervical Disc Arthroplasty Versus Fusion for the Treatment of Symptomatic Cervical Degenerative Disc Disease.

OBJECTIVE: Mobi-C cervical disc arthroplasty (MCDA) is an alternative to anterior cervical discectomy and fusion (ACDF). This study evaluated the effectiveness and safety of MCDA and ACDF for symptomatic cervical degenerative disc disease. METHODS: Databases were systematically searched for randomized controlled trials. Studies were included based on eligibility criteria. Risk of bias assessment and quality of evidence assessment were performed. RESULTS: Four studies with 785 patients were included. For clinical outcomes, MCDA were superior to ACDF with fewer subsequent surgical interventions (P < 0.00001), lower neck pain scores (P = 0.01), lower incidences of adjacent segment degeneration at both superior and inferior levels (P = 0.0003 and P = 0.01, respectively), greater range of motion of the operated segment (P < 0.0001), and higher patient satisfaction (P = 0.007). No significant differences were observed between groups regarding operative time, blood loss, duration of hospitalization, and neck disability index and arm pain scores (P > 0.05). Subgroup analyses indicated that for patients with 2-level cervical degenerative disc disease, MCDA demonstrated lower neck disability index and arm pain scores and higher patient satisfaction (P < 0.05) compared with ACDF. CONCLUSIONS: MCDA had fewer subsequent surgical interventions, lower neck pain scores, lower incidences of adjacent segment degeneration at superior and inferior levels, greater range of motion, and higher patient satisfaction scores than ACDF. MCDA was similar to ACDF regarding operative time, blood loss, duration of hospitalization, and neck disability index and neck pain scores.

Gelsolin Promotes Radioresistance in Non-Small Cell Lung Cancer Cells Through Activation of Phosphoinositide 3-Kinase/Akt Signaling.

Gelsolin is an actin-binding protein and acts as an important regulator of cell survival. This study aimed to determine the function of gelsolin in the radioresistance of non-small cell lung cancer cells. We examined the expression of gelsolin in radioresistant A549 and H460 cells and their parental cells. The effects of gelsolin overexpression and knockdown on the clonogenic survival and apoptosis of non-small cell lung cancer cells after irradiation were studied. The involvement of phosphoinositide 3-kinase/Akt signaling in the action of gelsolin was checked. We found that gelsolin was significantly upregulated in radioresistant A549 and H460 cells. Overexpression of gelsolin significantly ( P < .05) increased the number of colonies from irradiated A549 and H460 cells compared to transfection of empty vector. In contrast, knockdown of gelsolin significantly ( P < .05) suppressed colony formation after irradiation. Gelsolin-overexpressing cells displayed reduced apoptosis in response to irradiation, which was coupled with decreased levels of cleaved caspase-3 and poly adenosine diphosphate-ribose polymerase. Ectopic expression of gelsolin significantly ( P < .05) enhanced the phosphorylation of Akt compared to nontransfected cells. Pretreatment with the phosphoinositide 3-kinase inhibitor LY294002 (20 µmol/L) significantly decreased clonogenic survival and enhanced apoptosis in gelsolin-overexpressing A549 and H460 cells after irradiation. Taken together, gelsolin upregulation promotes radioresistance in non-small cell lung cancer cells, at least partially, through activation of phosphoinositide 3-kinase/Akt signaling.

Does local lavage influence functional recovery during lumber discectomy of disc herniation?: One year's systematic follow-up of 410 patients.

Lumbar disc herniation (LDH) is a common disease and lumbar discectomy is the most common surgical procedure carried out for patients with low back pain and leg symptoms. Although most researchers are focusing on the surgical techniques during operation, the aim of this study is to evaluate the effect of local intervertebral lavage during microdiscectomy.In this retrospective study, 410 patients were operated on by microdiscectomy for LDH during 2011 to 2014. Retrospectively, 213 of them (group A) accepted local intervertebral irrigation with saline water before wound closure and 197 patients (group B) only had their operative field irrigated with saline water. Systematic records of visual analog scores (VAS), Oswestry disability Index (ODI) questionnaire scale scores, use of analgesia, and hospital length of stay were done after hospitalization.The majority (80.49%) of the cases were diagnosed with lumber herniation at the levels of L4/5 and L5/S1. Fifty-one patients had herniations at 2 levels. There were significant decreases of VAS scores and ODI in both groups between preoperation and postoperation of different time points. VAS scores decreased more in group A than group B at early stage of postoperation follow-up. However, there were no statistically significant differences between 2 groups in using analgesia, VAS and ODI up to 1 month of follow-up.Microdiscectomy for LDH offers a marked improvement in back and radicular pain. Local irrigation of herniated lumber disc area could relief dick herniation-derived low back pain and leg radicular pain at early stage of post-operation. However, the pain relief of this intervention was not noticeable for a long period.

Resolved magnetic-field structure and variability near the event horizon of Sagittarius A.

Near a black hole, differential rotation of a magnetized accretion disk is thought to produce an instability that amplifies weak magnetic fields, driving accretion and outflow. These magnetic fields would naturally give rise to the observed synchrotron emission in galaxy cores and to the formation of relativistic jets, but no observations to date have been able to resolve the expected horizon-scale magnetic-field structure. We report interferometric observations at 1.3-millimeter wavelength that spatially resolve the linearly polarized emission from the Galactic Center supermassive black hole, Sagittarius A*. We have found evidence for partially ordered magnetic fields near the event horizon, on scales of ~6 Schwarzschild radii, and we have detected and localized the intrahour variability associated with these fields.

Effects of triptolide on the pharmacokinetics of cyclophosphamide in rats: a possible role of cytochrome P3A4 inhibition.

OBJECTIVE: To evaluate the effect of a 10-day course of triptolide (TP) on rat cytochrome (CY) P3A4 activity, and on the pharmacokinetics of cyclophosphamide (CPA). METHODS: In the pharmacokinetics experiment, rats were orally given 0.9% NaCl solution (n=5) and TP [1.2 (mg/kg·d)] for 10 days and a single dose of CPA was administered intravenously (100 mg/kg) to rats on day 11. Blood samples were collected up to 4 h at predetermined time intervals, the plasma concentration of CPA was determined by high performance liquid chromatography (HPLC) and pharmacokinetic parameters were determined. In the in vitro CYP3A4 activity inhibition research, rat blank liver microsomes were divided into 3 groups: a control group, a TS (5 µL, 200 µmol/L) with TP (5 µL, 12.5 µmol/L) group, a TS with ketoconazole (5 µL, 1 µmol/L) group. Concentration of 6ß-hydroxylated testosterone (6ß-OHT) in liver microsomes was measured by HPLC and the activity of CYP 3A4 was calculated through the following formula: Einhibitor/Econtrol × 100%=Cinhibitor/Ccontrol × 100%. RESULTS: Compared with the control group, the area under the plasma concentration-time curve (AUC0-∞) of CPA was significantly increased by 229.05% pretreated with TP (P<0.01). Peak plasma concentrations (Cmax) of CPA was significantly increased and plasma half-life was correspondingly extended. The CYP3A4 activity was significantly inhibited by ketoconazole 93.5%±0.2% and TP 84.6%±0.3% compared with the control group (P<0.01 and P<0.05, respectively). CONCLUSION: Our results strongly suggested that long-term oral intake of TP can distinctly inhibit the CYP3A4 activity and this inhibition evidently decrease the formation of toxic metabolites of CPA.

[Management of postoperative pain after total knee arthroplasty].

OBJECTIVE: To evaluate causes and clinical management of postoperative pain after total knee arthroplasty (TKA). METHODS: From January 2004 to June 2009, 41 patients (44 knees) with knee pain post TKA were treated. There were 9 male and 32 female patients aging from 51 to 84 years with a mean of 63.5 years. The diagnosis followed to Brown diagnostic system. One case of extraarticular pain was complex regional pain syndrome type 1 (CRPS-1) and underwent conservative treatment, the remaining 5 cases were treated by surgery. Three cases of joint instability, 1 case of patellar baja, 2 cases of soft tissue impingement caused by overhang of the prosthesis, 1 case of popliteal tendon impact underwent conservative treatment, the other 27 cases underwent surgical intervention. The patients were followed up and the Knee Society Score (KSS) knee score, pain visual analog scale (VAS) score were recorded. RESULTS: Forty-one cases were followed up for 1 to 6 years. At the last time of follow-up, the 5 cases received surgical treatment to extra-articular pain showed VAS score as 2.5 ± 0.2, KSS clinical and functional score as 92.8 ± 2.6 and 89.0 ± 3.4. There was significantly difference compared with preoperative (P < 0.05). One case of CRPS-1 performed conservative treatment, the therapy was effective. In the infected 12 cases of intra-articular pain, 1 case received amputation, 3 cases received antibiotic bone cement insert, 8 cases received two stage revision. All infections were cured, and VAS score was 3.8 ± 0.2, KSS clinical score was 88.3 ± 4.6, function score was 85.0 ± 4.6 postoperatively, with significantly difference compared with preoperative (P < 0.05). In the 8 cases received conservative treatment in non-infected group, at the last time of follow-up, VAS score was 4.5 ± 0.4, KSS clinical and functional score was 85.4 ± 4.2 and 84.2 ± 2.3, with significantly difference compared with preoperative (P < 0.05). Fifteen cases underwent surgical treatment, at the last time of follow-up, VAS score was 3.4 ± 0.1, KSS clinical and functional score was 86.6 ± 5.4 and 87.1 ± 2.4, with significantly difference compared with preoperative (P < 0.05). CONCLUSIONS: Patients with knee pain post TKA need systematic assessment to identify the causes. Appropriate treatment due to the positive diagnosis generally lead to satisfactory results, surgical intervention with indefinite causes is strictly prohibited.