459 research outputs found

    An alternative basis for the Kauffman bracket skein module of the Solid Torus via braids

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    In this paper we give an alternative basis, BST\mathcal{B}_{\rm ST}, for the Kauffman bracket skein module of the solid torus, KBSM(ST){\rm KBSM}\left({\rm ST}\right). The basis BST\mathcal{B}_{\rm ST} is obtained with the use of the Tempereley--Lieb algebra of type B and it is appropriate for computing the Kauffman bracket skein module of the lens spaces L(p,q)L(p, q) via braids.Comment: 14 pages, 5 figure

    Knot invariants in lens spaces

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    In this survey we summarize results regarding the Kauffman bracket, HOMFLYPT, Kauffman 2-variable and Dubrovnik skein modules, and the Alexander polynomial of links in lens spaces, which we represent as mixed link diagrams. These invariants generalize the corresponding knot polynomials in the classical case. We compare the invariants by means of the ability to distinguish between some difficult cases of knots with certain symmetries

    Fibroblast surface-associated FGF-2 promotes contact-dependent colorectal cancer cell migration and invasion through FGFR-SRC signaling and integrin αvβ5-mediated adhesion.

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    Carcinoma-associated fibroblasts were reported to promote colorectal cancer (CRC) invasion by secreting motility factors and extracellular matrix processing enzymes. Less is known whether fibroblasts may induce CRC cancer cell motility by contact-dependent mechanisms. To address this question we characterized the interaction between fibroblasts and SW620 and HT29 colorectal cancer cells in 2D and 3D co-culture models in vitro. Here we show that fibroblasts induce contact-dependent cancer cell elongation, motility and invasiveness independently of deposited matrix or secreted factors. These effects depend on fibroblast cell surface-associated fibroblast growth factor (FGF) -2. Inhibition of FGF-2 or FGF receptors (FGFRs) signaling abolishes these effects. FGFRs activate SRC in cancer cells and inhibition or silencing of SRC in cancer cells, but not in fibroblasts, prevents fibroblasts-mediated effects. Using an RGD-based integrin antagonist and function-blocking antibodies we demonstrate that cancer cell adhesion to fibroblasts requires integrin αvβ5. Taken together, these results demonstrate that fibroblasts induce cell-contact-dependent colorectal cancer cell migration and invasion under 2D and 3D conditions in vitro through fibroblast cell surface-associated FGF-2, FGF receptor-mediated SRC activation and αvβ5 integrin-dependent cancer cell adhesion to fibroblasts. The FGF-2-FGFRs-SRC-αvβ5 integrin loop might be explored as candidate therapeutic target to block colorectal cancer invasion

    Period polynomials, derivatives of L-functions, and zeros of polynomials

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    Period polynomials have long been fruitful tools for the study of values of L-functions in the context of major outstanding conjectures. In this paper, we survey some facets of this study from the perspective of Eichler cohomology. We discuss ways to incorporate non-cuspidal modular forms and values of derivatives of L-functions into the same framework. We further review investigations of the location of zeros of the period polynomial as well as of its analogue for L-derivatives

    The Role of Endoscopic Ultrasound in the Diagnosis and Management of Primary Gastric Lymphoma

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    Endoscopic ultrasound (EUS) is considered a valuable diagnostic tool during the workup of malignant gastric lesions, including primary gastric lymphomas (PGL). Although endoscopy combined with multiple biopsies remains essential in the establishment of PGL diagnosis, EUS utilization in locoregional disease staging has been well documented in the literature. Data also support the possible role of EUS in prediction of response to first-line treatment, that is, Helicobacter pylori eradication. However, its application in the posttreatment setting remains problematic, since concordance rates between endosonography and histology findings during follow-up seem to vary substantially. The aim of the present review is to summarize all available data regarding the role of EUS in the management of PGL

    Hydatid disease of the liver: thirty years of surgical experience.

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    Hydatid disease of the liver is a relatively frequent disease. Although the natural history is almost completely known, several complications may occur. The aim of this study was to show that radical surgical resection of the hepatic hydatid cyst is a safe and very effective technique, based on our results after 30-year experience. A review of most significant studies was carried out. We retrospectively evaluated our surgical cases. From January 1973 to December 2003 we treated 216 patients, 98 males and 118 females. Survival was compared with the Kaplan-Meier test, using log-rank analysis to compare data. Differences with a p value less than 0.05 were considered significant. A total of 279 cysts were excised. We performed pericystectomy in 122 cases, 73 of which closed. We also performed 19 atypical resections, 10 segmentectomies, 20 lobectomies and 2 percutaneous treatments. In more than 90% of cases, preoperative data collection was completed by preoperative ultrasound. The cumulative morbidity was 13%. The recurrence rate amounted to 4.3% at 5 years and 7% at 10 years: of these, 6 occurred after non-radical surgery and 2 after total pericystectomy or liver resection (p < 0.001). Technical advances and accumulated experience permit safe treatment of hepatic hydatid cysts by radical resection, with an almost zero recurrence rate, making it the treatment of choice over partial resection. The utility of percutaneous treatment remains confined to limited indications, such as laparoscopy

    Tourism stakeholder exclusion and conflict in a small island

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    Research in the Isle of Man, British Isles, reveals limited and dysfunctional collaboration between stakeholders, and in particular between public and private sector actors. Power and influence over tourism decision making is generally felt to be restricted to a small and opaque network. Moreover, different levels of interest in and support for tourism further divide stakeholders. Various negative consequences are shown to arise from this absence of collaboration, including a lack of shared vision or future strategy for local tourism, and high levels of mutual mistrust between stakeholders. Resulting conflict, wasted resources, lost enthusiasm and lack of strategic direction appear to undermine the current and future management of island tourism. Emphasised by research is the importance of stakeholder collaboration to sustainable tourism management and underlying factors which may enhance or undermine. Focus on dysfunctional collaboration and the small island setting makes a unique contribution to the existing literature

    Therapeutic index of lymphadenectomy among patients with pancreatic neuroendocrine tumors: A multi‐institutional analysis

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    BackgroundThe benefit derived from lymph node dissection (LND) in patients with pancreatic neuroendocrine tumors (pNETs) based on clinicopathological characteristics remains unclear.MethodsPatients undergoing surgery for pNET between 1997 and 2016 were identified using a multi‐institutional dataset. The therapeutic index of LND relative to patient characteristics was calculated.ResultsAmong 647 patients, the median number of lymph nodes (LNs) evaluated was 10 (interquartile range: 4‐16) and approximately one quarter of patients had lymph node metastasis (LNM) (N = 159, 24.6%). Among patients with LNM, 5‐year recurrence‐free survival was 56.0%, reflecting a therapeutic index value of 13.8. The therapeutic index was highest among patients with a moderately/poorly‐differentiated pNET (21.5), Ki‐67 ≥ 3% (20.1), tumor size ≥2.0 cm (20.0), and tumor location at the head of the pancreas (20.0). Patients with ≥8 LNs evaluated had a higher therapeutic index than patients who had 1 to 7 LNs evaluated (≥8: 17.9 vs 1‐7: 7.5; difference of index: 11.4).ConclusionLND was mostly beneficial among patients with pNETs >2 cm, Ki‐67 ≥ 3%, and lesions located at the pancreatic head as identification of LNM was most common among individuals with these tumor characteristics. Evaluation of ≥8 LNs was associated with a higher likelihood of identifying LNM as well as a higher therapeutic index, and therefore this number of LNs should be considered the goal.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151957/1/jso25689_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151957/2/jso25689.pd

    Attributable deaths and disability-adjusted life-years caused by infections with antibiotic-resistant bacteria in the EU and the European Economic Area in 2015: a population-level modelling analysis

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    Background: Infections due to antibiotic-resistant bacteria are threatening modern health care. However, estimating their incidence, complications, and attributable mortality is challenging. We aimed to estimate the burden of infections caused by antibiotic-resistant bacteria of public health concern in countries of the EU and European Economic Area (EEA) in 2015, measured in number of cases, attributable deaths, and disability-adjusted life-years (DALYs). Methods: We estimated the incidence of infections with 16 antibiotic resistance–bacterium combinations from European Antimicrobial Resistance Surveillance Network (EARS-Net) 2015 data that was country-corrected for population coverage. We multiplied the number of bloodstream infections (BSIs) by a conversion factor derived from the European Centre for Disease Prevention and Control point prevalence survey of health-care-associated infections in European acute care hospitals in 2011–12 to estimate the number of non-BSIs. We developed disease outcome models for five types of infection on the basis of systematic reviews of the literature. Findings: From EARS-Net data collected between Jan 1, 2015, and Dec 31, 2015, we estimated 671 689 (95% uncertainty interval [UI] 583 148–763 966) infections with antibiotic-resistant bacteria, of which 63·5% (426 277 of 671 689) were associated with health care. These infections accounted for an estimated 33 110 (28 480–38 430) attributable deaths and 874 541 (768 837–989 068) DALYs. The burden for the EU and EEA was highest in infants (aged <1 year) and people aged 65 years or older, had increased since 2007, and was highest in Italy and Greece. Interpretation: Our results present the health burden of five types of infection with antibiotic-resistant bacteria expressed, for the first time, in DALYs. The estimated burden of infections with antibiotic-resistant bacteria in the EU and EEA is substantial compared with that of other infectious diseases, and has increased since 2007. Our burden estimates provide useful information for public health decision-makers prioritising interventions for infectious diseases

    Unravelling the mechanism of water sensing by the Mg2+ dihydroxy-terephthalate MOF (AEMOF-1 ‘)

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    In this contribution we build upon our previous work on the MOF [Mg(H(2)dhtp)(H2O)(2)]center dot DMAc (AEMOF-1 center dot DMAc) and its activated dry version AEMOF-1 ‘ which has been shown to exhibit excellent luminescence sensing properties towards water in organic solvents. We demonstrate through combined structural and photophysical studies that the observed changes in the fluorescence properties of AEMOF-1 ‘ upon hydration arise from a structural transformation to the mononuclear complex [Mg(H(2)dhtp)(H2O)(5)]center dot H2O (H(4)dhtp = 2,5-dihydroxyterepthalic acid) (1). In the latter complex, excited state intramolecular proton transfer (ESIPT) is strongly favoured thereby leading to enhanced and red shifted emission in comparison to AEMOF-1 center dot DMAc. Powder X-ray diffraction measurements confirmed that complex 1 is identical to the hydrated form of AEMOF-1 center dot DMAc. As in the case of AEMOF-1 ‘, the dry form of complex 1 (1 ‘) is also an effective sensor for the determination of traces of water in tetrahydrofuran (THF). This work demonstrates that the same chromophore may exhibit very different emission properties when it exists in different chemical environments and that these transformations may be controlled and utilized in water sensing applications
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