Search

We predict that a combined system of Ir dimer situated on the single-vacancy (SV) graphene is extremely stable and has high magnetic anisotropy energy (MAE), promising to be a potential candidate for high density magnetic storage. Our theoretical results show that high energy gradient in the SV graphene makes it possible to move the Ir dimer from the perfect graphene area into the center of SV (CSV), leading to the formation of the highly stable system with the Ir-Ir bond axis exactly perpendicular to the graphene plane. The calculated MAE value is as large as 25.7 meV per Ir atom. The origin of giant MAE in such a system is attributed to the difference of local densities of electronic states magnetized along different directions caused by special symmetry of Ir2 at CSV. We also propose a feasible avenue to assemble the Ir dimers on the graphene with the pattern of SV defects for actual applications. [ABSTRACT FROM AUTHOR]

Objective: To construct and compare macrophage by gene modification of Wnt5a which co-cultured by human bone marrow-derived mesenchymal stem cells (MSCs) with two dimension (2D) and bone marrow aspirates in vitr transwell, in order to investigate the effect of Wnt5a signaling on cartilage homeostasis through regulation of macrophage pro-inflammatory responses., Methods: Macrophages, MSCs and bone marrow aspirates specimens were extracted from 6 patients with severe knee deformities undergoing total knee arthroplasty(2 males, 4 females, aged from 58 to 71 years old) from September 2015 to December 2018. The synovial tissues of knee joints were exposed to type II collagenase and obtained single cell suspensions, and the purity of macrophages was determined by Ficoll gradient centrifugation and anti-CD14 antibody flow cytometry. The macrophages were transduced with IFN-γ combined with TNF-α for 48 h, and rAAV-lacZ or Wnt5a transfected for 24 h, then co-cultured model by human bone marrow-derived mesenchymal stem cells (MSCs) with two dimension (2D) and bone marrow aspirates in vitro transwell. HE staining, toluidine blue staining, X-gal staining and anti-Wnt5a, anti-II, X collagen immunohistochemical staining and enzyme-linked immunosorbent assay were applied to detect cell morphology and proliferation (cellularity), viral transfection efficiency respectively., Results: Results of anti-CD68 immunohistochemistry showed macrophage of patients with osteoarthritis increased obviously. Anti-CD 14 flow cytometry confirmed that percentage of isolated synovial macrophages was 90.31%. The level of monocyte chemotactic protein-1 in supernatants was significantly increased after stimulation with IFN-γ and TNF-α, indicating that the macrophages were activated and at proinflammatory condition. After transduction with rAAV-lacZ for 3 days, X-gal staining indicated that lacZ gene transfer could efficiently transduce the activated macrophages with the efficiency over 97.50% for at least 21 days. After transfection macrophages by rAAV-Wnt5a stimulated expression of Wnt5a, and enhanced expression of Wnt5a between two models and inhibited the secretion of MCP-1. The expression of MCP-1 in Wnt5a group was 14.76 and 61.51 pg/ml respectively. In addition, rAAV-Wnt5a gene transfer could promote cell proliferation, chondrogenic differentiation and cartilage matrix synthesis., Conclusions: Under the condition of macrophage and MSCs 2D monolayer or aspirates transwe ll co-culture, rAAV-mediated over-expression of Wnt5a could promote maintenance of cartilage homeostasis and chondrogenic differentiation of MSCs via macrophage inflammatory response, macrophages may affect cartilage homeostasis and MSCs chondrogenesis through Wnt5a signaling pathway., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© 2019 by the China Journal of Orthopaedics and Traumatology Press.)

Objective: To investigate the risk factors of functional recovery after intramedullary nail fixation for femoral intertrochanteric fracture in elderly patients, and to propose corresponding measures to promote postoperative hip function recovery., Methods: From June 2012 to June 2015, 74 patients after intramedullary nail fixation surgery were analyzed, including 33 males and 41 females, with an average age of(75.07±7.89) years old, and divided into well-function group(55 patients) and bad-function group(19 patients) according to Sanders function criterion. Age, gender, bone density, fracture type, systemic disease, complication, rehabilitation exercises with therapist or not, nourishment state, anesthesia method, fracture reduction condition, ASA classification, tip apex distance were reviewed and analyzed by t test, non-parametric test, χ² test and Logistic analysis., Results: Univariate analysis showed that age, bone density, nourishment state, ASA classification, anesthesia method, fracture reduction condition, rehabilitation exercises with therapist, and tip apex distance were the risk factors for the recovery of hip function. Logistic analysis showed that bone density( P= 0.006, OR=0.077), rehabilitation exercises with therapist( P= 0.006, OR=0.070), ASA classification( P <0.001, OR=0.049), nourishment state ( P= 0.046, OR=0.188) were the risk factors for the functional recovery., Conclusions: Bone density, rehabilitation exercises with therapist, ASA classification, nourishment state were the risk factors for the functional recovery of intramedullary nail fixation for intertrochanteric fracture in elderly patients. Multidisciplinary cooperation and fast track surgery system should be set up to promoting the hip functional recovery., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© 2018 by the China Journal of Orthopaedics and Traumatology Press.)

Objective: To analyze the complications of percutaneous kyphoplasty except bone leakge for the treatment of osteoporotic thoracolumbar vertebral compression fractures., Methods: From October 2008 to October 2012,178 patients with 224 osteoporotic vertebral compression fractures were treated with percutaneous kyphoplasty under local anethsia. There were 72 males and 106 females,ranging in age from 58 to 92 years old,with an average of 75.3 years,including 93 thoracic vertebrae and 131 lumbar vertebrae. The complications except bone cement leakage were analyzed during operation and after operation., Results: All operations were successful and all patients were followed up from 12 to 60 months with an average of 26.2 months. No death was found. Bone cement leakage occurred in 27 cases, about 15.1% in 178 cases; and complications except bone cement leakage occurred in 15 cases. There was 1 case with cardiac arrest,was completely recovery by cardiopulmonary resuscitation (CPR) immediately; and 1 case with temporary absence of breathing,was recovery after treatment. There were 3 cases with fall of blood pressure and slower of heart rate; 1 case with intestinal obstruction; 2 cases with local hematoma and 1 case with intercostal neuralgia. Vertebral body fractures of 2 cases were split by bone cement and the fractures of adjacent body occurred in 4 cases., Conclusion: It's uncommon complication except bone cement leakge in treatment of osteoporotic thoracolumbar vertebral compression fractures with percutaneous kyphoplasty. The complication of cardiopulmonary system is a high risk in surgery; and cytotoxicity of bone cement,nervous reflex,fat embolism and alteration of intravertebral pressure may be main reasons.

Objective: To evaluate the clinical outcomes of percutaneous kyphoplasty (PKP) in treating senile osteoporotic vertebral compression fractures under local anesthesia., Methods: From May 2007 to May 2010,129 patients with osteoporotic vertebral compression fractures were treated with PKP under local anesthesia. There were 47 males and 82 females, ranging in age from 61 to 92 years old,with an average of 73.7 years old,including 88 segments of thoracic vertebrae and 101 segments of lumbar vertebrae. Visual analogue scale (VAS),height of vertebral body,Cobb's angle were evaluated before and after operation., Results: Operations were performed successfully in all patients and these patients were followed up from 24 to 60 months with an average of 34.2 months. Preoperative,postoperative two weeks and at final follow-up,VAS score was 7.9+/-2.5,2.8+/-1.8,3.0+/-2.2,respectively;Cobb angle was (28.3+/-13.7)degree, (16.2+/-9.8)degree, (19.1+/-10.3)degree, respectively. There was significant difference between postoperative and preoperative, and between at final follow up and preoperative (P<0.05). The height of vertebral body obtained partial recovery. Bone cement leakage occurred in 23 vertebrae (with proportion of 17.8%) during operation,among one patient with temporary clinical symptom of radiculalgia. All lumbago obtained obviously anesis after operation, 1 case complicated with respiratory depression and recovered after resuscitation; 1 case complicated with intestinal obstruction and improved after treatment, 1 case complicated with fracture separation of vertebral body by bone cement, and 4 cases complicated with fracture of adjacent vertebral body., Conclusion: Percutaneous vertebral kyphoplasty is an effective method for treatment of senile osteoporotic vertebral compression fractures,which can expeditiously relieve pain and effectively recovery height of vertebral body and Cobb angle,it has advantages of minimal invasive. The results of short and mid-term follow-up were satisfactory, long-term follow-up is still needed. Correctly choosing the operative indication and improving surgical technique may avoid complications, especially bone cement leakage which is the most frequent complication.

Objective: To analyze the perioperative complications of percutaneous kyphoplasty (PKP) for osteoporotic vertebral compression fracture., Methods: From June 2009 to December 2011, 63 patients with osteoporotic vertebral compression fracture underwent PKP, there were 18 males and 45 females with an average age of 75.3 years ( ranged, 62 to 91). All patients with severe back pain and without neurological symptoms and signs, which were confirmed by X-ray and MRI. Among them,there were 63 cases with severe osteoporosis, 37 cases with hypertension, 10 with coronary artery disease, 29 with anemia, 26 with diabetes, 11 with chronic obstructive pulmonary diseases and 8 with gastritis and peptic ulcer. The common perioperative complications were retropectively reviewed., Results: Preoperative complications occured in 9 cases (14.3%), including hypostatic pneumonia (1 case), electrolyte disturbances (2 cases), urinary tract infection (2 cases), moderate anemia(2 cases),electrolyte disturbances combined with moderate anemia (1 case), hypostatic pneumonia combined with delirium (1 case). Intraoperative and postoperative. complications occurred in 17 cases (26.9%), there were bone cement correlated complications in 9 cases (14.3%), in which 2 cases of toxic reaction of bone cement and 7 cases of leakage (2 cases had clinical symptoms); there were non-bone cement correlated complications in 3 cases (4.8%), in which 1 case of focal hematoma caused by paracentesis, 1 case of transient nerve injury, 1 case of left intercostal neuralgia;there were transient hyperpathia in 5 cases after operation. All complications result in no severe consequence after treatment., Conclusion: Perioperative complications of percutaneous kyphoplasty are not uncommon,however,these complications may not cause serious consequence after active treatment,so prevention and treatment are important for it.