Saturated VSD model of a six-phase induction machine

In this paper, a saturated model of an asymmetrical six-phase induction machine is presented. The model is based on the vector space decomposition approach, and it includes main and leakage flux saturation, as well as the mutual coupling between orthogonal planes, while using the Gamma equivalent circuit approach. The accuracy of the proposed model in unbalanced operating modes that are characteristic for multiphase machines, such as post-fault and power sharing operation, makes it advantageous compared to existing models. The model is developed assuming that the machine operates in asymmetrical conditions and that, therefore, there is fundamental frequency excitation in both planes. The inter-plane coupling effect is examined using finite element analysis and an experimental procedure for its quantification is developed. The model is verified by comparison with the experimental results obtained from a prototype asymmetrical six-phase induction machine, and its advantages compared to existing models are emphasized

HIV-1 Tat mimetic of VEGF correlates with increased microvessels density in AIDS-related diffuse large B-cell and Burkitt lymphomas

Angiogenic switch marks the beginning of tumor’s strategy to acquire independent blood supply. In some subtypes of non-Hodgkin’s lymphomas, higher local vascular endothelial growth factor (VEGF) expression correlates with increased microvessel density. However, this local VEGF expression is higher only in tumors with elevated expression of the receptors of the growth factor, suggesting an autocrine growth-promoting feedback loop. Several studies have indicated that VEGF receptors are also targeted by Tat protein from the HIV-1-infected cells. Given the similarity of the basic region of Tat to the angiogenic factors (basic fibroblast growth factor, VEGF), Tat mimics these proteins and binds to their receptors. We evaluated the role of HIV-1 Tat in regulating the level of VEGF expression and microvessel density in the AIDS-related diffuse large B-cell (DLBCL) and Burkitt lymphomas (BL). By luciferase assay, we showed that VEGF promoter activity was downregulated in vitro in cells transfected with Tat. Reduced VEGF protein expression in primary HIV-1 positive BL and DLBCL, compared to the negative cases, supported the findings of promoter downregulation from the cell lines. Microvascular density assessed by CD34 expression was, however, higher in HIV-1 positive than in HIV-1 negative tumors. These results suggest that Tat has a wider angiogenic role, besides the regulation of VEGF expression. Thus, targeting Tat protein itself and stabilizing transient silencing of VEGF expression or use of monoclonal antibodies against their receptors in the AIDS-associated tumors will open a window for future explorable pathways in the management of angiogenic phenotypes in the AIDS-associated non-Hodgkin’s lymphomas

Real-Time Visualization and Quantitation of Vascular Permeability In Vivo: Implications for Drug Delivery

The leaky, heterogeneous vasculature of human tumors prevents the even distribution of systemic drugs within cancer tissues. However, techniques for studying vascular delivery systems in vivo often require complex mammalian models and time-consuming, surgical protocols. The developing chicken embryo is a well-established model for human cancer that is easily accessible for tumor imaging. To assess this model for the in vivo analysis of tumor permeability, human tumors were grown on the chorioallantoic membrane (CAM), a thin vascular membrane which overlays the growing chick embryo. The real-time movement of small fluorescent dextrans through the tumor vasculature and surrounding tissues were used to measure vascular leak within tumor xenografts. Dextran extravasation within tumor sites was selectively enhanced an interleukin-2 (IL-2) peptide fragment or vascular endothelial growth factor (VEGF). VEGF treatment increased vascular leak in the tumor core relative to surrounding normal tissue and increased doxorubicin uptake in human tumor xenografts. This new system easily visualizes vascular permeability changes in vivo and suggests that vascular permeability may be manipulated to improve chemotherapeutic targeting to tumors

Angiopoietin-1 enhances neutrophil chemotaxis in vitro and migration in vivo through interaction with CD18 and release of CCL4

Angiopoietins are a family of growth factors that are ligands for the tyrosine kinase receptor, Tie2. Angiopoietin 1 (Ang-1) is agonistic for Tie2, plays a key role in blood vessel maturation and stability and has been shown to possess anti-inflammatory properties. However, Tie2 expression has been demonstrated on human neutrophils and the observation that neutrophils migrate in response to Ang-1 in vitro has confounded research into its exact role in inflammation as well as its potential use as a therapeutic agent. We used a mouse model of peritoneal neutrophilic inflammation to determine if Ang-1 could stimulate neutrophil migration in vivo. Tie2 expression was demonstrated on mouse neutrophils. In addition, recombinant human Ang-1 induced significant chemotaxis of isolated mouse neutrophils in a Tie2- and CD18-dependent manner. Subsequently, co-immunoprecipitation of Ang-1 and CD18 demonstrated their interaction. Intraperitoneal injection of an engineered angiopoietin-1, MAT.Ang-1, induced significant neutrophil migration into the peritoneum and a significant increase in the levels of CCL4 in peritoneal lavage fluid. Depletion of resident peritoneal macrophages prior to, or concomitant injections of an anti-CCL4 antibody with MAT.Ang-1 resulted in a significant reduction in neutrophil recruitment. These data indicate a pro-inflammatory role for Ang-1 with respect to neutrophil recruitment.British Heart Foundation Studentship FS/06/081/2172

Radiographic changes in alveolar bone height on overdenture abutments: a longitudinal study

Objective: Stabilisation of partial dentures is an important part of prosthodontic treatment, particularly in patients with an excessive reduction in alveolar bone supporting their abutment teeth. In these cases, overdenture prostheses are one possible treatment choice. Background: The aim of this study was to evaluate the effects of overdentures on the condition of alveolar bone of the remaining teeth, and to evaluate the overdenture concept in the prosthetic treatment of partially edentulous patients. Materials and methods: The investigation was conducted on 22 patients during observation periods of 6 and 10 years. After preparation, all abutment teeth were provided with either amalgam restorations or gold copings. An overdenture in the lower jaw was fabricated for every patient. A special film holder was used to repeat the X-ray procedure in every patient in the same manner. The radiographs were evaluated using the grid scale. The alveolar bone level of all remaining teeth was evaluated on dental films by measuring the distance between the root apex and coronal border of the alveolar bone. Results: A statistically significant difference (p lt 0.01) was calculated 6 years after delivery stage between distal alveolar bone levels of experimental abutments under overdentures and the remaining teeth of the control group. Alveolar bone of abutment teeth was considerably preserved, particularly in seven patients observed 10 years after provision of their dentures. Conclusion: Within the limitation of this study, the validity of the overdenture treatment in partially edentulous patients is concluded. Good oral hygiene was crucial for the success of treatment with overdentures