Discontinuous phase transition switching induced by a power-law function between dynamical parameters in coupled oscillators.

In biological or physical systems, the intrinsic properties of oscillators are heterogeneous and correlated. These two characteristics have been empirically validated and have garnered attention in theoretical studies. In this paper, we propose a power-law function existed between the dynamical parameters of the coupled oscillators, which can control discontinuous phase transition switching. Unlike the special designs for the coupling terms, this generalized function within the dynamical term reveals another path for generating the first-order phase transitions. The power-law relationship between dynamic characteristics is reasonable, as observed in empirical studies, such as long-term tremor activity during volcanic eruptions and ion channel characteristics of the Xenopus expression system. Our work expands the conditions that used to be strict for the occurrence of the first-order phase transitions and deepens our understanding of the impact of correlation between intrinsic parameters on phase transitions. We explain the reason why the continuous phase transition switches to the discontinuous phase transition when the control parameter is at a critical value.

Giant nontraumatic myositis ossificans in a child: A case report.

BACKGROUND: Nontraumatic myositis ossificans is a rare disease whose specific pathogenesis is unclear. Early diagnosis of this disease is very difficult in children because of difficulties in determining medical history and nonspecific early clinical manifestations, which may lead to the failure of timely and effective diagnosis and treatment in some patients. We report the diagnosis and treatment of a child with nontraumatic myositis ossificans and summarize the clinical characteristics and diagnosis and treatment of the disease. CASE SUMMARY: An 8-year-old girl first came to our hospital for more than a week with pain in the right lower limb. There was no history of trauma or strenuous activities. On physical examination, no mass on the right thigh was found, and the movement of the right lower extremity was limited. Ultrasonography showed synovitis of the hip, and bed rest was recommended. Three days later, the child's pain persisted and worsened, accompanied by fever and other discomforts. She came to our hospital again and a mass was found on the right thigh with redness and swelling on the surface. The images showed a soft tissue tumor on the right thigh with calcification. Routine blood tests revealed that the inflammation index was significantly increased. In case of infection, the patient was given antibiotics, and the pain was relieved soon after, without fever. However, the right thigh mass persisted and hardened. The patient underwent incision biopsy more than 1 mo later, and the postoperative pathology showed nontraumatic myositis ossificans. After approximately 9 mo of observation, the tumor still persisted, which affected the life of the child, and then resection was performed. Since follow-up, there has been no recurrence. CONCLUSION: Due to the difficulty in discerning a child's medical history and the diverse early manifestations, it is difficult to diagnose nonossifying muscle disease in children in its early stage. Measures such as timely follow-up and periodic image monitoring are conducive to early diagnosis of the disease. The disease has a certain degree of self-limitation, and it can be observed and treated first. If the tumor persists in the later stage or affects functioning, then surgery is considered.

Comparison of different treatments for children with radial neck fracture and analysis of prognostic factors.

INTRODUCTION: The aim of this was to analyze the effect of different treatment options on radial neck fractures in children and to explore the factors affecting the prognosis of fractures. METHODS: The clinical data of 131 children with radial neck fractures admitted to our hospital from 2010 to 2018 were retrospectively analyzed, and the patients were divided into 6 groups according to treatment methods [manual reduction with Kirschner wires (K-wires) for internal fixation (group A); manual reduction with elastic stable intramedullary nails (ESINs) for internal fixation (group B); leverage reduction with K-wires for internal fixation (group C); leverage reduction with ESINs for internal fixation (group D); manual and leverage reduction with K-wires/ESINs for internal fixation (group E); and open reduction with K-wires/ESINs for internal fixation (group F)]. Postoperative elbow function and complications were analyzed. RESULTS: Among the 131 patients with fractures, the median age was 8 years, the median preoperative angulation was 52°, the follow-up rate was 86.3% (113/131), the average follow-up time was 58.3 months, and the postoperative complication rate was 17.7% (20/113). The comparison among the different treatment groups showed that group B had the best recovery of elbow function, postoperatively, and the lowest postoperative complication rate. Age, duration of hospitalization, and preoperative angulation were independent factors affecting postoperative complications. Older age, longer duration of hospitalization, and higher angulation increase the postoperative complications. CONCLUSION: Different treatment options have different efficacies for radial neck fractures in children, of which manipulative reduction with internal fixation using ESINs can achieve good efficacy and a low postoperative complication rate. Age, duration of hospitalization, and preoperative angulation are independent factors for postoperative complications.

Human GPR4 and the Notch signaling pathway in endothelial cell tube formation.

G protein-coupled receptor 4 (GPR4) is hypothesized to function as a pH sensor and is important in the regulation of proliferation, migration and angiogenesis of vascular endothelial cells (ECs). Furthermore, the Notch signaling pathway is significant in the regulation of the angiogenic behavior of ECs. However, whether GPR4 regulates angiogenesis via the Notch signaling pathway remains unclear. The present study evaluated the effect of Notch signaling in human GPR4­induced angiogenesis in HMEC­1 cells. The results revealed that GPR4 increased Notch1 expression in a time­dependent manner. In addition, the inhibition of Notch1 expression using small interfering RNA or the Notch receptor inhibitor, γ-secretase inhibitor I, significantly blocked GPR4­induced HMEC­1 tube formation and lymphocyte transendothelial migration. Furthermore, the inhibition of Notch1 blocked GPR4­induced vascular endothelial growth factor and hypoxia-inducible factor 1α expression. Thus, it was demonstrated that GPR4 affects ECs by regulating Notch1, a function that may be important for physiological and pathological angiogenesis.

RNAi targeting GPR4 influences HMEC-1 gene expression by microarray analysis.

G-protein coupled receptor 4 (GPR4) belongs to a protein family comprised of 3 closely related G protein-coupled receptors. Recent studies have shown that GPR4 plays important roles in angiogenesis, proton sensing, and regulating tumor cells as an oncogenic gene. How GPR4 conducts its functions? Rare has been known. In order to detect the genes related to GPR4, microarray technology was employed. GPR4 is highly expressed in human vascular endothelial cell HMEC-1. Small interfering RNA against GPR4 was used to knockdown GPR4 expression in HMEC-1. Then RNA from the GPR4 knockdown cells and control cells were analyzed through genome microarray. Microarray results shown that among the whole genes and expressed sequence tags, 447 differentially expressed genes were identified, containing 318 up-regulated genes and 129 down-regulated genes. These genes whose expression dramatically changed may be involved in the GPR4 functions. These genes were related to cell apoptosis, cytoskeleton and signal transduction, cell proliferation, differentiation and cell-cycle regulation, gene transcription and translation and cell material and energy metabolism.

Effects of BMP2 and VEGF165 on the osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells.

Bone marrow-derived mesenchymal stem cells (MSCs) are dominant seed cell sources for bone regeneration. Bone morphogenetic proteins (BMPs) initiate cartilage and bone formation in a sequential cascade. Vascular endothelial growth factor (VEGF) is an essential coordinator of extracellular matrix remodeling, angiogenesis and bone formation. In the present study, the effects of the vascular endothelial growth factor 165 (VEGF165) and bone morphogenetic protein 2 (BMP2) genes on bone regeneration were investigated by the lentivirus-mediated cotransfection of the two genes into rat bone marrow-derived MSCs. The successful co-expression of the two genes in the MSCs was confirmed using quantitative polymerase chain reaction (qPCR) and western blot analysis. The results of alizarin red and alkaline phosphatase (ALP) staining at 14 days subsequent to transfection showed that the area of staining in cells transfected with BMP2 alone was higher than that in cells transfected with BMP2 and VEGF165 or untransfected control cells, while the BMP2 + VEGF165 group showed significantly more staining than the untransfected control. This indicated that BMP2 alone exhibited a stronger effect in bone regeneration than BMP2 in combination with VEGF165. Similarly, in inducing culture medium, the ALP activity of the BMP2 + VEGF165 group was notably suppressed compared with that of the BMP2 group. The overexpression of VEGF165 inhibited BMP2-induced MSC differentiation and osteogenesis in vitro. Whether or not local VEGF gene therapy is likely to affect bone regeneration in vivo requires further investigation.