403 research outputs found

    The FastMap Algorithm for Shortest Path Computations

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    We present a new preprocessing algorithm for embedding the nodes of a given edge-weighted undirected graph into a Euclidean space. The Euclidean distance between any two nodes in this space approximates the length of the shortest path between them in the given graph. Later, at runtime, a shortest path between any two nodes can be computed with A* search using the Euclidean distances as heuristic. Our preprocessing algorithm, called FastMap, is inspired by the data mining algorithm of the same name and runs in near-linear time. Hence, FastMap is orders of magnitude faster than competing approaches that produce a Euclidean embedding using Semidefinite Programming. FastMap also produces admissible and consistent heuristics and therefore guarantees the generation of shortest paths. Moreover, FastMap applies to general undirected graphs for which many traditional heuristics, such as the Manhattan Distance heuristic, are not well defined. Empirically, we demonstrate that A* search using the FastMap heuristic is competitive with A* search using other state-of-the-art heuristics, such as the Differential heuristic

    Operative planning in Thoracic Surgery: A pilot study comparing imaging techniques and 3D printing.

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    BACKGROUND: Careful preoperative planning in thoracic surgery is essential for positive outcomes especially in video assisted thoracic surgery (VATS) where palpation and 3-dimensional imaging is restricted. The objective of this study was to evaluate the ability of different imaging techniques such as Computerized Tomography (CT) scanning, maximal intensity projection (MIP) imaging, 3-dimensional (3D) reconstruction as well as 3D printing, to define the anatomy of the hilar structures prior to anatomical lung resection. METHODS: All patients undergoing elective lung resections by VATS for cancer under a single surgeon were identified over a three-month period. A single surgeon was asked to record the number of pulmonary artery branches supplying the lobe to be resected using the preoperative CT scan, MIP images and 3D reconstructed CT images. 3 patients had their lung hilum printed. These were then compared to the intraoperative findings. RESULTS: 16 patients had their preoperative imaging analyzed. A further 3 patients had their lung hilum 3D printed. Although not statistically significant, the 3D prints of the hilum were found to be the most accurate measurement with a correlation of 0.92. CT, 3D reconstructed CT and MIP images tended to under recognize the number of arterial branches and therefore scored between 0.26 and 0.39 in terms of absolute agreement with the number of arteries found at operation. CONCLUSIONS: 3D printing in the planning of thoracic surgery may suggest a benefit over contemporary available imaging modalities and the use of 3D printing in practicing operations is being established

    Health risk assessment of engine exhaust emissions within Australian ports: a case study of Port of Brisbane

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    Emissions from ocean-going vessels present a significant health risk to populations surrounding ports and damage the environment. Emissions from ships using heavy fuel oil include substantial amounts of sulphur dioxide, nitrogen oxides, and particulate matter. In order to assess the risk of these emissions, a complete methodology has been developed, based on the Australian Environmental Health Risk Assessment Framework. The method includes a detailed inventory of in-port and at-sea emissions using an activity-based approach applying downwash and near-field areas from first principles equations as well as the air-shed regions from CALPUFF dispersion modeling results for Port of Brisbane in 2013. The final risk values are validated against national and European guidelines. Various health impact assessments, as well as carcinogenic and ecological effects, are discussed in depth. This study offers a significant contribution to developing a baseline measurement of the current state of risk from emissions of the ocean-going vessels visiting the port, and suggests that, given the expected development of many Australian ports in the near future, the need for continual monitoring of shipping emissions is an essential and necessary area of research

    The EXCEL Trial: The Surgeons' Perspective.

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    There have been several investigations comparing the efficacy of percutaneous coronary intervention and coronary artery bypass grafting surgery for treatment of left main stem disease. This includes the Evaluation of XIENCE versus Coronary Artery Bypass Graft Surgery for Effectiveness of Left Main Revascularizaton (EXCEL) trial, which has garnered significant controversy surrounding its experimental design and reporting of its results. The authors review the methodology, results, caveats and statements on the EXCEL trial. They also review the other trials in the management of left main stem disease comparing percutaneous coronary intervention with coronary artery bypass grafting, as well as the SYNTAX score and its role in future guidelines for revascularisation. These findings have significant implications for current practice, influencing the growing role for multidisciplinary team meeting and allowing clinicians and patients to make the right choice

    Water safety in drought: An indigenous knowledge-based qualitative study

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    The indigenous knowledge of our ancestors provides valuable information on how to prevent negative health impacts on water hygiene in the event of drought. The present study aimed to explore the role of indigenous knowledge in maintaining water safety in drought conditions. A qualitative content analysis method using in-depth semi-structured interviews was used to collect and analyze the data. The current research was carried out from April 2017 to June 2018. A purposive sampling method was used to select 15 participants. Trustworthiness was applied with the Lincoln and Guba approach and data were analyzed using Graneheim and Lundman's method. Two categories including drinking water storage and water collection were extracted from the data. Each category includes different strategies to deal with water. Water storage includes water quantity and water quality. Water collection consists of collection methods and rules. Indigenous knowledge is an indispensable component of community disaster resilience. It can be transferred to other communities and employed to empower affected communities. But using the knowledge without scientific considerations cannot guarantee peoples' health throughout the drought periods. © IWA Publishing 2020 Journal of Water and Healt

    Numerical simulation of a liquid cyclotron target

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    One of the most common PET isotopes, 18F, is mainly produced in liquid targets. The production yield depends linearly on the proton beam current used. However, for a fixed proton-beam energy increasing the current of the proton beam results in depositing increasing amounts of heat into the enclosed water target chamber and eventually in its failure. Hence, understanding the thermodynamics of a water target chamber could lead to a target optimization, removing the maximum amount of heat to balance the pressure, increasing the yield and guaranteeing the stability and durability of the system. Work in modeling the thermodynamic processes in a liquid target has also been per-formed by other groups [1-3] and others such as Steinbach [4] have performed analytical analyses of thermal behavior

    Obesity and PCOS radically alters the snRNA composition of follicular fluid extracellular vesicles

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    IntroductionThe ovarian follicle consists of the oocyte, somatic cells, and follicular fluid (FF). Proper signalling between these compartments is required for optimal folliculogenesis. The association between polycystic ovarian syndrome (PCOS) and extracellular vesicular small non-coding RNAs (snRNAs) signatures in follicular fluid (FF) and how this relates to adiposity is unknown. The purpose of this study was to determine whether FF extracellular vesicle (FFEV)-derived snRNAs are differentially expressed (DE) between PCOS and non-PCOS subjects; and if these differences are vesicle-specific and/or adiposity-dependent.MethodsFF and granulosa cells (GC) were collected from 35 patients matched by demographic and stimulation parameters. FFEVs were isolated and snRNA libraries were constructed, sequenced, and analyzed.ResultsmiRNAs were the most abundant biotype present, with specific enrichment in exosomes (EX), whereas in GCs long non-coding RNAs were the most abundant biotype. In obese PCOS vs. lean PCOS, pathway analysis revealed target genes involved in cell survival and apoptosis, leukocyte differentiation and migration, JAK/STAT, and MAPK signalling. In obese PCOS FFEVs were selectively enriched (FFEVs vs. GCs) for miRNAs targeting p53 signalling, cell survival and apoptosis, FOXO, Hippo, TNF, and MAPK signalling.DiscussionWe provide comprehensive profiling of snRNAs in FFEVs and GCs of PCOS and non-PCOS patients, highlighting the effect of adiposity on these findings. We hypothesize that the selective packaging and release of miRNAs specifically targeting anti-apoptotic genes into the FF may be an attempt by the follicle to reduce the apoptotic pressure of the GCs and stave off premature apoptosis of the follicle observed in PCOS

    Oncolytic adenovirus: A tool for cancer therapy in combination with other therapeutic approaches

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    Cancer therapy using oncolytic viruses is an emerging area, in which viruses are engineered to selectively propagate in tumor tissues without affecting healthy cells. Because of the advantages that adenoviruses (Ads) have over other viruses, they are more considered. To achieve tumor selectivity, two main modifications on Ads genome have been applied: small deletions and insertion of tissue- or tumor-specific promoters. Despite oncolytic adenoviruses ability in tumor cell lysis and immune responses stimulation, to further increase their antitumor effects, genomic modifications have been carried out including insertion of checkpoint inhibitors and antigenic or immunostimulatory molecules into the adenovirus genome and combination with dendritic cells and chemotherapeutic agents. This study reviews oncolytic adenoviruses structures, their antitumor efficacy in combination with other therapeutic strategies, and finally challenges around this treatment approach. © 2018 Wiley Periodicals, Inc
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