Topological charge-density-vector method of identifying filaments of scroll waves.

Scroll waves have been found in a variety of three-dimensional excitable media, including physical, chemical, and biological origins. Scroll waves in cardiac tissue are of particular significance as they underlie ventricular fibrillation that can cause sudden death. The behavior of a scroll wave is characterized by a line of phase singularity at its organizing center, known as a filament. A thorough investigation into the filament dynamics is the key to further exploration of the general theory of scroll waves in excitable media and the mechanisms of ventricular fibrillation. In this paper, we propose a method to identify filaments of scroll waves in excitable media. From the definition of the topological charge of filaments, we obtain the discrete expression of the topological charge-density vector, which is useful in calculating the topological charge vectors at each grid in the space directly. The set of starting points of these topological charge vectors represents a set of phase singularities, thereby forming a line of phase singularity, that is, a filament of a scroll wave.

Topological charge-density method of identifying phase singularities in cardiac fibrillation.

Spiral waves represent the key motifs of typical self-sustained dynamical patterns in excitable systems such as cardiac tissue. The motion of phase singularities (PSs) that lies at the center of spiral waves captures many qualitative and, in some cases, quantitative features of their complex dynamics. Recent clinical studies suggested that ablating the tissue at PS locations may cure atrial fibrillation. Here, we propose a different method to determine the location of PSs. Starting from the definition of the topological charge of spiral waves, we obtain the expression of the topological charge density in a discrete case. With this expression, we can calculate the topological charge at each grid in the space directly, so as to accurately identify the position of PSs.

Primary testicular diffuse large B-cell lymphoma: Case series.

RATIONALE: Primary testicular lymphoma (PTL) is a rare type of extranodal non-Hodgkin's lymphoma (NHL). Although data of PTL in patients with diffuse large B-cell lymphoma (DLBCL) are accumulating, there are still patients respond poorly to prognosis. PATIENT CONCERNS: All patients had disease of the DLBCL subtype and those patients had primary involvement of the testis. In our studies, eleven patients had stage I/II disease, and 3 patients had advanced disease with B symptoms. Four patients exhibited a MYC+, BCL2+, and BCL6- expression pattern, 4 patients had a MYC+, BCL6+, and BCL2- expression pattern, and 3 patients had a MYC+, BCL2+, and BCL6+ expression pattern. Additionally, 43% (7/16) of PT-DLBCL patients had a germinal center B-cell-like (GCB) phenotype, while the others had a non-GCB phonotype. DIAGNOSES: In our case, most patients presented with unilateral painless scrotal swelling and the enlargement of the testicles in the first examination. After hospitalization, all patients underwent preoperative imageological examination of the testis and epididymis and postoperative revealed that all patients were the diffuse infiltration of a large number of anomalous lymphocytes. In addition, no invasion of other sites was observed within 3 months after diagnosis. INTERVENTIONS AND OUTCOMES: Underwent orchiectomy on the affected side was performed by urologists after all patients were diagnosed with PTL. Meanwhile, some patients received at least one course of chemotherapy, or received postoperative combined RT and chemotherapy. Because of it particularity, nineteen instances of lymph node region involvement were discovered in 12 patients since the operation. LESSONS: PT-DLBCL has unique biological characteristics, and its treatment modalities are becoming increasingly standardized. In the future, systematic interventions need to be actively considered in the early stages of PTL.

FOXM 1 induces Vasculogenic mimicry in esophageal cancer through ß-catenin /Tcf4 signaling.

OBJECTIVE: To investigate the role of FOXM1, ß-catenin and TCF4 in esophageal cancer (EC) and their relationship to VM (Vasculogenic Mimicry). METHODS: CCK-8 were performed to examine EC cell proliferation in FOXM1 silenced cells. EC cell migration and invasion were investigated through wound healing and Transwell assays, respectively. The formation of pipe like structures were assessed in 3D cultures. The expression of Foxm1, ß-catenin, Tcf4 and E-cadherin were investigated through western blot, RT-qPCR and immunohistochemistry (IHC) staining. The relationship between FOXM1 expression, clinic-pathological features, and overall survival (OS) were further analyzed. RESULTS: A loss of FOXM1 expression correlated with the OS of ESCC patients. FOXM1 silencing led to a loss of cell growth and suppressed cell migration and invasion in ESCC cells. VM structures were identified in ESCC tissues and human EC cell lines. Mechanistically, FOXM1 was found to promote tumorigenesis through the regulation of ß-catenin, Tcf4, and E-cadherin in EC cells, leading to the formation of VM structures. CONCLUSIONS: These findings highlight FoxM1 as a novel therapeutic target in ESCC.

The Emerging Role of Sperm-Associated Antigen 6 Gene in the Microtubule Function of Cells and Cancer.

Accumulated evidence shows that sperm-associated antigen 6 (SPAG6) gene has multiple biological functions. It maintains the normal function of a variety of cells including ciliary/flagellar biogenesis and polarization, neurogenesis, and neuronal migration. Moreover, SPAG6 is found to be critically involved in auditory transduction and the fibroblast life cycle. Furthermore, SPAG6 plays an essential role in immuno-regulation. Notably, SPAG6 has been demonstrated to participate in the occurrence and progression of a variety of human cancers. New evidence shows that SPAG6 gene regulates tumor cell proliferation, apoptosis, invasion, and metastasis. Therefore, in this review, we describe the physiological function and mechanism of SPAG6 in human normal cells and cancer cells. We also highlight that SPAG6 gene may be an effective biomarker for the diagnosis of human cancer. Taken together, targeting SPAG6 could be a novel strategy for the treatment of human diseases including cancer.

Aberrant expression of MYH9 and E-cadherin in esophageal squamous cell carcinoma and their relationship to vasculogenic mimicry.

PURPOSE: To investigate whether vasculogenic mimicry (VM) exists in esophageal squamous cell carcinoma (ESCC) and to elucidate the relationship among expression of MYH9, E-cadherin and VM. METHODS: The expression of MYH9 (non-muscle myosin heavy chain 9), E-cadherin protein and VM in 120 specimens of esophageal squamous cell carcinoma (ESCC) and 120 specimens of normal esophageal mucosa were detected by using immunohistochemical and histochemical staining. RESULTS: VM channels were identified in 58 (48.33%) of the 120 ESCC specimens and none of the normal esophageal mucosa was found to have VM. The rates of expression of MYH9 and E-cad in ESCC were 57.50% and 40.00%, while rates in the control group were 13.33% and 73.33%, respectively (P<0.05). VM and the expression levels of MYH9 and E-cad were significantly connected with lymph node metastasis, serosa invasion, pTNM staging and 5-year-survival rates of patients with ESCC (P<0.05). VM was positively correlated with MYH9, but negatively correlated with E-cad, and MYH9 was negatively significantly correlated with E-cad. The 5-year-survival rates of patients with ESCC were 6.89% (4/58) in the VM group and 67.74% (42/62) in the non-VM group, 8.00% (4/50) in high MYH9 expression group and 60.00% (42/70) in low MYH9 expression group. However, the 5-year-survival rate in high E-cad expression group was 86.95% (40/46) and that in low E-cad expression group was 8.11% (6/74) (P<0.05). Cox multifactorial regression analysis demonstrated that lymph node metastasis, pTNM stage, VM and expression levels of MYH9 and E-cad were independent risk factors in patients with ESCC (P<0.05). CONCLUSION: ESCC'patients with VM had a poor differentiation and a bad clinical prognosis; Combined detection of VM, MYH9 and E-cad may play an essential role in predicting the invasion, metastasis, and progression of patients with ESCC.

Dynamics of opinion formation in a small-world network.

The dynamical process of opinion formation within a model using a local majority opinion updating rule is studied numerically in networks with the small-world geometrical property. The network is one in which shortcuts are added to randomly chosen pairs of nodes in an underlying regular lattice. The presence of a small number of shortcuts is found to shorten the time to reach a consensus significantly. The effects of having shortcuts in a lattice of fixed spatial dimension are shown to be analogous to that of increasing the spatial dimension in regular lattices. The shortening of the consensus time is shown to be related to the shortening of the mean shortest path as shortcuts are added. Results can also be translated into that of the dynamics of a spin system in a small-world network.

Effects of contrarians in the minority game.

We study the effects of the presence of contrarians in an agent-based model of competing populations. Contrarians are common in societies. These contrarians are agents who deliberately prefer to hold an opinion that is contrary to the prevailing idea of the commons or normal agents. Contrarians are introduced within the context of the minority game (MG), which is a binary model for an evolving and adaptive population of agents competing for a limited resource. The average success rate among the agents is found to have a nonmonotonic dependence on the fraction a(c) of contrarians. For small a(c), the contrarians systematically outperform the normal agents by avoiding the crowd effect and enhance the overall success rate. For high a(c), the anti-persistent nature of the MG is disturbed and the few normal agents outperform the contrarians. Qualitative discussion and analytic results for the small a(c) and high a(c) regimes are presented, and the crossover behavior between the two regimes is discussed.

Weighted scale-free networks with stochastic weight assignments.

We propose a model of weighted scale-free networks incorporating a stochastic scheme for weight assignments to the links, taking into account both the popularity and fitness of a node. As the network grows, the weights of links are driven either by the connectivity with probability p or by the fitness with probability 1-p. Numerical results show that the total weight exhibits a power-law distribution with an exponent sigma that depends on the probability p. The exponent sigma decreases continuously as p increases. For p=0, the scaling behavior is the same as that of the connectivity distribution. An analytical expression for the total weight is derived so as to explain the features observed in the numerical results. Numerical results are also presented for a generalized model with a fitness-dependent link formation mechanism.

Investigations on copper-titanate intercalation materials for amperometric sensor.

Copper-based titanate intercalation electrode materials (referred as Cu-TO) were achieved by electrochemical reduction of the intercalated cupric ions that were ion exchanged on the layer structured titanate films by using n-propylamine as an exfoliating agent. The copper-based titanate intercalation electrode materials were characterized by X-ray diffraction (XRD), electrochemical techniques and inductive coupled plasma-atomic emission spectroscopy (ICP-AES). These copper-based titanate materials were exploited to fabricate the enzymeless glucose sensors, and their assay performances to glucose were evaluated by conventional electrochemical techniques. Cyclic voltammetry (CV) and chronoamperometry (I-t) revealed a high sensitivity, fast response, excellent stability, and good reproducibility in the glucose determination at +0.55 V. Under optimal conditions, the electrocatalytic response of the sensor was proportional to the glucose concentration in the range of 2.5x10(-7) M to 8.0x10(-3) M with a detection limit of 5.0x10(-8) M (signal-to-noise=3). Moreover, the intercalated copper electrode materials exhibited high stability and improved selectivity for glucose compared with the more apparently accessible copper. This work also provides a simply controlled test-bed for electrochemical functionalization of layered titanate for sensor applications.