1,632 research outputs found
Excision margins in breast conserving surgery
The ideal excision margin in breast
conserving surgery is still a matter of debate. The aim is to
see if there is any correlation between increasing
excision margin distance and local recurrence rate.
Patients who had breast
conserving surgery at Mater Dei Hospital in 2009 had
their notes reviewed retrospectively. Patient
demograpichs, including the excision margins were
recorded. Local recurrences within a 3 year follow up
period were noted. Chi square was used to compare
categorical data and a p value of less than 0.05 was
considered statistically significant.
91 patients were recruited into the study. 74
patients (81.5%) had negative margins (>1mm), 10
patients (11%) had close margins (<1mm) while 7
patients (7.5%) had positive margins. 5 patients (5.5%)
had local recurrence. The highest recurrence rate (14%)
was in patients with positive margins, and no statistical
signficant difference in recurrence rates was noted with
wider excision margins.
As long as the margins are negative,
increasing excision margins will not result in a better
local recurrence rate.peer-reviewe
Identification of taxonomic and functional ichthyofaunal zones within the James River Basin, Virginia
Environmental gradients structure ichthyofaunal communities longitudinally along river networks via the selective filtering of species’ traits. In many instances, these environmental influences have created distinct zones of co-occurring fish species. Zonation studies have most often been conducted with taxonomic data (species x site matrices), but the increasing availability of functional trait data creates an opportunity to build more rigorous understanding of species’ co-occurrence patterns. Notably, zonation studies that use taxonomic data may not reveal the same patterns as studies based on trait data. In this study, we tested for distinct ichthyofaunal zonation in James River Basin, VA using a combination of historical (1950-1987) and contemporary fish occurrence records (1986-2016) that were aggregated within 12-digit hydrologic units (HU). Zonation tests were performed separately for taxonomic data and functional trait data, using a combination of non-metric multidimensional scaling and k-means cluster analysis. We detected three distinct taxonomic zones and three functional trait zones within the James River Basin. In addition, through identifying that taxonomic dissimilarity between HUs was strongly correlated with functional dissimilarity, these zonation patterns were determined to not be significantly different
Assessing knee OA severity with CNN attention-based end-to-end architectures
This work proposes a novel end-to-end convolutional neural network (CNN) architecture to automatically quantify the severity of knee osteoarthritis (OA) using X-Ray images, which incorporates trainable attention modules acting as unsupervised fine-grained detectors of the region of interest (ROI). The proposed attention modules can be applied at different levels and scales across any CNN pipeline helping the network to learn relevant attention patterns over the most informative parts of the image at different resolutions. We test the proposed attention mechanism on existing state-of-the-art CNN architectures as our base models, achieving promising results on the benchmark knee OA datasets from the osteoarthritis initiative (OAI) and multicenter osteoarthritis study (MOST).Postprint (published version
Inertial Force-Driven Synthesis of Near-Infrared Plasmonic Nanosphere Composites: Physicochemical Characterizations
Near-infrared (NIR) responsive nanoparticles (NPs) like gold nanorods (GNRs) are important in biomedical fields because of their transparency for biological tissues. Although GNRs are sought after as contrast agents for theranostics in cancer studies, capping ligands like cetyltrimethylammonium bromide (CTAB) for the GNR synthesis are toxic for biological tissues. The need for an alternative to toxic GNRs is of interest to alleviate the problem.
This work aimed to optimize the synthesis of NIR responsive nanosphere composites (NSCs) by inertial force (g-force) using colloidal gold NPs as model, elucidate the mechanism for the NSC formation, and study their detailed physicochemical characteristics. The inertial force-driven synthesis of NSCs resulted in NP composites of two NPs combined together with little or no gaps between them. The synthesis process was simple and cost-effective, and did not require the use of a toxic chemical like CTAB. The formed NSCs showed rod-like characteristics, which are typified by the evolution of absorption spectra from the transverse to longitudinal mode.
Factors, such as NP sizes, g-force, capping ligand, and electrostatic force, were found to influence NSC formation. Variations of g-forces showed that there was a critical g-force to form NSCs at fixed centrifugation duration and those critical g-force values were inversely proportional to centrifugation duration. This implied that both g-forces and the duration of NPs\u27 exposure to g-forces should be considered to investigate optimal reaction conditions for maximal NSC yields and detailed mechanisms of their formation. When three combinations of gold NPs with different sizes were used, NSCs with NPs of two different sizes (hetero-dimers) were formed and their NIR plasmonic responses shifted further to the right compared to those of homo-dimers, demonstrating high promise of tuning NIR plasmonic responses of NSCs. Evaluating capping ligands of NPs with different charge characteristics, only absorbance spectra of NPs with charged ligands evolved from the transverse to longitudinal mode, confirming that NP surface charge characteristics played important roles in the NSC formation. Although more works remain and challenges ahead, these new nanomaterials by the inertial force-driven technique showed high potential to be an effective alternative to many existing nanoparticles, particularly GNRs
\u3cem\u3eRhizobium leguminosarum\u3c/em\u3e CFN42 Genetic Regions Encoding Lipopolysaccharide Structures Essential for Complete Nodule Development on Bean Plants
Eight symbiotic mutants defective in lipopolysaccharide (LPS) synthesis were isolated from Rhizobium leguminosarum biovar phaseoli CFN42. These eight strains elicited small white nodules lacking infected cells when inoculated onto bean plants. The mutants had undetectable or greatly diminished amounts of the complete LPS (LPS I), whereas amounts of an LPS lacking the O antigen (LPS II) greatly increased. Apparent LPS bands that migrated between LPS I and LPS II on sodium dodecyl sulfate-polyacrylamide gels were detected in extracts of some of the mutants. The mutant strains were complemented to wild-type LPS I content and antigenicity by DNA from a cosmid library of the wild-type genome. Most of the mutations were clustered in two genetic regions; one mutation was located in a third region. Strains complemented by DNA from two of these regions produced healthy nitrogen-fixing nodules. Strains complemented to wild-type LPS content by the other genetic region induced nodules that exhibited little or no nitrogenase activity, although nodule development was obviously enhanced by the presence of this DNA. The results support the idea that complete LPS structures, in normal amounts, are necessary for infection thread development in bean plants
Haiti
One step at a time, Joesph PhillippeGlimmers of hope in the embers of despair, Noel O\u27Mear
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