Background: Axillary lymph node dissection as routine part of breast cancer treatment has been questioned in relation to the balance between benefits and morbidity. The purpose of this study is to determine the association of tumor size, age and histological grade with axillary lymph node metastasis, to determine if some patients could be exempted from axillary dissection. Methods: The data are derived from BreastScreen NSW, the government sponsored population-based breast screening program. In New South Wales (NSW) Australia between 1995 and 2002, 7,221 patients with invasive breast carcinoma were diagnosed and 5,290 patients were eligible for this study. The relationship between incidence of positive axillary lymph nodes and three study factors (tumor size, age and histological grade) was investigated by univariate and multivariate analysis. Logistic regression models were used to predict probability of axillary metastases. Results: The incidence of axillary lymph node metastases was 28.6% (95% CI: 27.4%- 29.8%). Univariate analysis showed that age, tumor size and histological grade were significant predictors of axillary lymph node metastases (p<0.0001). Multivariate analysis identified age, tumor size and histological grade remained as independent predictors (p<0.0001). From multivariate analysis, patients with T1a (Less than or equal to 5mm) and grade I tumors regardless of age had 5.2% (95% CI: 1.2%- 9.3%) frequency of node metastases. Patients 70 years or older with grade I, T1a and T1b (6-10mm) tumors had 4.9% (95% CI: 3.2%- 7.5%) and 6.6% (95% CI: 5.3%-8.3%) predicted frequency of node metastases. Conclusions: Tumor size, age and histological grade are predictors of axillary lymph node metastases. Routine axillary lymph node dissection could be avoided in some patient groups with a low frequency of involved lymph nodes if the benefits are considered to exceed the risks.

Background: Sick sinus syndrome (SSS) is common and may require electronic pacemaker implantation, gene therapy (biopacemaking) may be an alternative. For SSS, repair may be better than the generation of a de novo biopacemaker, due to the complex nature of the sinoatrial node (SAN). We hypothesised that an ex vivo model of SSS could be created by the identification of a subsidiary pacemaker in the SAN region, and that expression of a pacemaker channel (HCN4 or HCN212) in this region would accelerate the pacing rate. Methods: A bradycardic SSS model was generated by the removal of the upper two thirds of a rat SAN and a system to record the intrinsic activity during tissue culture was developed. The leading pacemaker site of the SSS preparations were identified by activation mapping then characterised by If blockade, β-adrenergic stimulation, histology and immunohistochemistry. Further SSS preparations were injected in this region with recombinant adenovirus (RAd) expressing no functional ion channel (Ad5-GFP or Ad5-GFP-HCN4Δ); or RAd expressing a functional If channel (Ad5-HCN212 or Ad5-PREK-HCN4). During tissue culture electrical activity was monitored using bipolar electrodes. Results: Tissue culture and monitoring of the rat SAN is feasible and does not induce significant changes in HCN4 or connexin-43 expression. The uninjected SSS preparations displayed a slower rate than the control SAN (p<0.001). In 5/6 cases the subsidiary pacemaker was HCN4 -ve and Connexin-43 +ve (in contrast to the SAN) and was close to the superior aspect of the inferior vena cava. The cell size of the subsidiary pacemaker was comparable to that of the SAN and smaller than working myocardium (p<0.001). Pacing was responsive to β-adrenergic stimulation and was partially dependent on If current. The pacing rate of the AdHCN212-injected SSS preparations was significantly faster than the uninjected SSS preparations (p<0.001). The remaining RAd did not significantly affect the pacing rate of the SSS model. Conclusions: There is subsidiary pacemaker tissue close to the superior aspect of the IVC that shares some characteristics of the SAN. These results suggest that adenovirus-mediated expression of HCN channels in subsidiary pacemaker tissue of the right atrium may be a useful strategy in biopacemaking for SSS.

Background: Pulmonary arterial hypertension (PAH) is a condition with severe morbidity and mortality. It is associated with an increase in incidence of all forms of arrhythmias which further increase morbidity and mortality. The monocrotaline (MCT) model of pulmonary hypertension (PH) in the rat is analogous to PAH in humans and was used to study how PH causes arrhythmias. Methods: A single injection of MCT or a volume matched saline injection (control) was given to the rats on day 0 of the protocol. The hearts of both groups of rats were studied in vivo with echocardiography (echo) and electrocardiogram (ECG). The rat’s condition was monitored and they were electively sacrificed when they showed symptoms or on day 28. Live cardiac tissue was studied using the Langendorff preparation and a right atrial preparation that incorporated the sinoatrial (SA) and atrioventricular (AV) nodes. Molecular biology techniques including reverse transcription quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry were used identify changes in the heart caused by PH. The effects of macitentan, an endothelin receptor antagonist used in the treatment of PAH, on the MCT injected rats was assessed using echo and ECGResults: Echo demonstrated that the MCT treated rats developed severe pulmonary hypertension with a decreased pulmonary artery acceleration time (P<0.005) and an increased pulmonary artery deceleration (P<0.005). The MCT treated rats also developed right ventricular hypertrophy (P<0.05) and dilation (P<0.005). The in vivo ECG demonstrated QT prolongation (P<0.005). Ex vivo functional experiments demonstrated QT prolongation (P<0.005) and prolonged ventricular effective refractory period (P<0.005). AV node dysfunction was also seen in the ex vivo experiments with an increased AV effective refractory period (P<0.05), AV functional refractory period (P<0.05) and incidence of complete heart block (P<0.05). RT-qPCR demonstrated significant changes in the mRNA expression of several ion channels and exchanges, Ca2+ handling proteins and autonomic receptors including a downregulation of HCN4 and CaV1.2 in the AV nodal tissues (P<0.05). Treatment of established pulmonary hypertension led to a reduction in the prolongation of the QT interval caused by MCT administration at day 21 (P<0.05).Conclusions: PH causes arrhythmogenic changes including prolonged repolarisation in the working myocardium and AV node dysfunction. These changes may be caused by dysregulation of ion channels and Ca2+ handling proteins. These ion channels and Ca2+handling proteins may play a key role in both physiological and pathological processes within the AV node.

The process of removing snow from the streets of cities in an optimal way can pose quite a challenge. In order to optimize the path of the snow removing vehicle, the city can be translated into a graph with nodes as crossings and links as roads. Once the city is modelled as a graph, all nodes with degree one can be eliminated and the snow removal time is added to the closest node. An optimization problem can then be solved in order to find a vehicle path in this reduced graph. The purpose of this thesis is to give an algorithm to reconstruct the reduced graph and then dictate the proper vehicle path in this reconstructed graph. The algorithm is constructed by reversing the node elimination process, piecing together the original graph and traversing the graph to get information about what to do on the eliminated links and nodes. The obtained algorithm is presented in this thesis.

ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / The scope of this document is the description of design and implementation of the wireless sensor network realized as a part of our Senior Design Capstone Project. The various components and sub-systems that comprise the final product are discussed, followed by the implementation procedures and results.

ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / Today's telemetry systems need to be highly configurable and easily extensible to support a constantly growing number of data acquisition/transmitting components from different manufacturers. One way to achieve this goal is through a standardized descriptive language that can define the system structure as well as end-node devices. The integrated Network Enhanced Telemetry (iNET) program has explored such a possibility by creating a series of standards to define how devices are configured and interoperate with each other. As one of the standards created by the iNET program, the Metadata Description Language (MDL) specifies a common interchange language that defines and configures a Telemetry Network System (TmNS). MDL Instance Documents are used to exchange test requirements, data formats and configuration information among the devices within a TmNS system. MDL, together with other standards created in the iNET program, serve as a foundation for assembling a modern telemetry system. This paper starts with an overview of the MDL-based system description architecture. A typical configuration workflow of an MDL-based system is then described. iNET functionality implementations for new and legacy devices are used as examples to illustrate the power of MDL-based design, as well as the challenges and issues associated with the implementation of the MDL standard. We explain and evaluate the design decisions for a new product, the L-3 NetDAS Recorder, as the case study. We also discuss how a legacy Data Acquisition Unit (DAU) acting as an LTC Data Source Unit can be updated to support MDL based iNET functionality. Our practice shows that more efficient data acquisition systems can be designed and implemented using the metadata definition language as a core tool for equipment and system description. We conclude the paper with design tradeoffs and discussions.

Network design problems involving survivability usually include trade-off of the potential for lost revenues and customer goodwill against the extra costs required to increase the network survivability. It also involves selection of nodes and edges from lists of potential sets to accomplish certain desirable properties. In many applications it is imperative to have built-in reliability or survivability of the network. Delays of traffic are undesirable since it affects quality of service (QoS) to clients of the network. In this dissertation we consider the construction of an optimization system for network design with survivability properties that may help in the planning of mesh topologies while maintaining a certain degree of survivability of the network. This is done by providing for at least two diverse paths between certain "special" nodes to provide protection against any single edge or node failure. This part is modelled by using mixed integer programming techniques. A software product called CPLEX then solves these models and various facilities are built into the decision support system to allow the decision maker to experiment with some topological and flow requirement changes. / Thesis (M.Sc. (Computer Science))--North-West University, Potchefstroom Campus, 2007

A research report submitted to the Faculty of Health Sciences, University of Witwatersrand, in fulfillment of the requirements for the degree of Master of Medicine in the branch of Internal Medicine Johannesburg, 2015 / Lymphadenopathy is a common clinical presentation of disease in South Africa (SA), particularly in the era of Human Immunodeficiency Virus (HIV) and tuberculosis (TB) coinfection. Methods Data from 560 lymph node biopsy reports of specimens from patients older than 12 years at Chris Hani Baragwanath Academic Hospital (CHBAH) between 1 January 2010 and 31 December 2012 was extracted from the National Health Laboratory Service (NHLS), division of Anatomical Pathology. Cytology reports of lymph node fine needle aspirates (FNAs) performed prior to lymph node biopsy in 203 patients were also extracted from the NHLS. Consent was not obtained from participants for their records to be used as patient information was anonymized and de-identified prior to analysis. Results The majority of patients were female (55%) and of the African/black racial group (90%). The median age of patients was 40 years (range12-94). The most common indication for biopsy was an uncertain diagnosis (more than two differential diagnoses entertained), followed by a suspicion for lymphoma, carcinoma and TB. Overall, malignancy constituted the largest biopsy pathology group (39%), with 36% of this group being carcinoma and 27% non-Hodgkin lymphoma. 22% of the total sampled nodes displayed necrotizing granulomatous inflammation (including histopathology and cytology demonstrating definite, and suspicious for mycobacterial infection), 8% comprised HIV reactive nodes; in the remainder no specific pathology was identified (nonspecific reactive lymphoid hyperplasia). Kaposi sarcoma (KS) accounted for 3% of lymph node pathology in this sample. Concomitant lymph node pathology was diagnosed in four cases of nodal KS (29% of the subset). The co-existing pathologies were TB and Castleman disease. HIV-positive patients constituted 49% of this study sample and the majority (64%) of this subset had CD4 counts less than 350 cells/ul. 27% were HIVnegative and in the remaining nodes, the HIV status of patients was unknown. The most common lymph node pathologies in HIV-positive patients were Mycobacterial infection (31%), HIV reactive nodes (15%), non-Hodgkin lymphoma (15%) and nonspecific reactive lymphoid hyperplasia (15%). Only 9% were of Hodgkin lymphoma. In contrast, the most common lymph node pathologies in HIV-negative patients were nonspecific reactive lymphoid hyperplasia (45%), carcinoma (25%) and Mycobacterial infection (11%). In this group, non-Hodgkin lymphoma and Hodgkin lymphoma constituted 9% and 8%, respectively. There were more cases of high-grade non-Hodgkin lymphoma in the HIV-positive group compared to the HIV-negative group. FNA and lymph node biopsy had excellent agreement with regard to Hodgkin lymphoma (K 0.774, SE 0.07, 95% CI 0.606-0.882, p=0.001), and good agreement with regard to non-Hodgkin lymphoma (K 0.640, SE 0.07, 95% CI 0.472-0.807, p=0.001), carcinoma (K 0.723, SE 0.069, 95% CI 0.528-0.918, p=0.001), and mycobacterial infection (K 0.726, SE 0.07, 95% CI 0.618-0.833, p=0.001). Conclusions The most common lymph node pathologies in CHBAH are malignancies, nonspecific reactive lymphoid hyperplasia, necrotizing granulomatous inflammation and HIV reactive nodes. The distribution of disease differed in HIV-positive patients. Overall, adequate FNA samples of lymph nodes have been found to have good correlation with lymph node biopsy findings in our setting.

Although Bayesian Networks (BNs) are increasingly being used to solve real world problems [47], their use is still constrained by the difficulty of constructing the node probability tables (NPTs). A key challenge is to construct relevant NPTs using the minimal amount of expert elicitation, recognising that it is rarely cost-effective to elicit complete sets of probability values. This thesis describes an approach to defining NPTs for a large class of commonly occurring nodes called ranked nodes. This approach is based on the doubly truncated Normal distribution with a central tendency that is invariably a type of a weighted function of the parent nodes. We demonstrate through two examples how to build large probability tables using the ranked nodes approach. Using this approach we are able to build the large probability tables needed to capture the complex models coming from assessing firm's risks in the safety or finance sector. The aim of the first example with the National Air-Traffic Services(NATS) is to show that using this approach we can model the impact of the organisational factors in avoiding mid-air aircraft collisions. The resulting model was validated by NATS and helped managers to assess the efficiency of the company handling risks and thus, control the likelihood of air-traffic incidents. In the second example, we use BN models to capture the operational risk (OpRisk) in financial institutions. The novelty of this approach is the use of causal reasoning as a means to reduce the uncertainty surrounding this type of risk. This model was validated against the Basel framework [160], which is the emerging international standard regulation governing how financial institutions assess OpRisks.

Thesis (M.Sc. (Computer Science))--North-West University, Potchefstroom Campus, 2007.