1,001 research outputs found

    The homotopy type of the loops on (n1)(n-1)-connected (2n+1)(2n+1)-manifolds

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    For n2n\geq 2 we compute the homotopy groups of (n1)(n-1)-connected closed manifolds of dimension (2n+1)(2n+1). Away from the finite set of primes dividing the order of the torsion subgroup in homology, the pp-local homotopy groups of MM are determined by the rank of the free Abelian part of the homology. Moreover, we show that these pp-local homotopy groups can be expressed as a direct sum of pp-local homotopy groups of spheres. The integral homotopy type of the loop space is also computed and shown to depend only on the rank of the free Abelian part and the torsion subgroup.Comment: Trends in Algebraic Topology and Related Topics, Trends Math., Birkhauser/Springer, 2018. arXiv admin note: text overlap with arXiv:1510.0519

    Counting all dyons in N =4 string theory

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    For dyons in heterotic string theory compactified on a six-torus, with electric charge vector Q and magnetic charge vector P, the positive integer I = g.c.d.(Q \wedge P) is an invariant of the U-duality group. We propose the microscopic theory for computing the spectrum of all dyons for all values of I, generalizing earlier results that exist only for the simplest case of I=1. Our derivation uses a combination of arguments from duality, 4d-5d lift, and a careful analysis of fermionic zero modes. The resulting degeneracy agrees with the black hole degeneracy for large charges and with the degeneracy of field-theory dyons for small charges. It naturally satisfies several physical requirements including integrality and duality invariance. As a byproduct, we also derive the microscopic (0,4) superconformal field theory relevant for computing the spectrum of five-dimensional Strominger-Vafa black holes in ALE backgrounds and count the resulting degeneracies

    Activity of the DNA minor groove cross-linking agent SG2000 (SJG-136) against canine tumours

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    BACKGROUND: Cancer is the leading cause of death in older dogs and its prevalence is increasing. There is clearly a need to develop more effective anti-cancer drugs in dogs. SG2000 (SJG-136) is a sequence selective DNA minor groove cross-linking agent. Based on its in vitro potency, the spectrum of in vivo and clinical activity against human tumours, and its tolerability in human patients, SG2000 has potential as a novel therapeutic against spontaneously occurring canine malignancies. RESULTS: In vitro cytotoxicity was assessed using SRB and MTT assays, and in vivo activity was assessed using canine tumour xenografts. DNA interstrand cross-linking (ICL) was determined using a modification of the single cell gel electrophoresis (comet) assay. Effects on cell cycle distribution were assessed by flow cytometry and measurement of γ-H2AX by immunofluorescence and immunohistochemistry. SG2000 had a multi-log differential cytotoxic profile against a panel of 12 canine tumour cell lines representing a range of common tumour types in dogs. In the CMeC-1 melanoma cell line, DNA ICLs increased linearly with dose following a 1 h treatment. Peak ICL was achieved within 1 h and no removal was observed over 48 h. A relationship between DNA ICL formation and cytotoxicity was observed across cell lines. The formation of γ-H2AX foci was slow, becoming evident after 4 h and reaching a peak at 24 h. SG2000 exhibited significant anti-tumour activity against two canine melanoma tumour models in vivo. Anti-tumour activity was observed at 0.15 and 0.3 mg/kg given i.v. either once, or weekly x 3. Dose-dependent DNA ICL was observed in tumours (and to a lower level in peripheral blood mononuclear cells) at 2 h and persisted at 24 h. ICL increased following the second and third doses in a repeated dose schedule. At 24 h, dose dependent γ-H2AX foci were more numerous than at 2 h, and greater in tumours than in peripheral blood mononuclear cells. SG2000-induced H2AX phosphorylation measured by immunohistochemistry showed good correspondence, but less sensitivity, than measurement of foci. CONCLUSIONS: SG2000 displayed potent activity in vitro against canine cancer cell lines as a result of the formation and persistence of DNA ICLs. SG2000 also had significant in vivo antitumour activity against canine melanoma xenografts, and the comet and γ-H2AX foci methods were relevant pharmacodynamic assays. The clinical testing of SG2000 against spontaneous canine cancer is warranted. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12917-015-0534-2) contains supplementary material, which is available to authorized users

    Phase II study of gemcitabine and vindesine in patients with previously untreated non-resectable non-small-cell lung cancer

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    Because both vindesine and gemcitabine are active drugs in advanced non-small-cell lung cancer (NSCLC), with different modes of action and only partly overlapping toxicity, a phase II study was performed. Gemcitabine 1000 mg m−2 was given on days 1, 8 and 15 every 4 weeks, while vindesine 3 mg m−2 was administered weekly for 7 weeks, then every 2 weeks. A total of 42 patients with nonresectable NSCLC were included. The median age of patients was 56 years; 57% were men, 52% had adenocarcinoma, 31% squamous cell carcinoma and 17% had large-cell carcinoma. The performance status ranged from 0 to 2 with 83% in performance status 1. The majority (55%) had stage IV disease, while 40% had stage III B and 5% stage III A disease. WHO grade 3–4 leucopenia occurred in five patients (12%) and 9% had grade 4 neutropenia. Thrombocytopenia grade 3–4 was observed in six patients (15%). There were no septic death or bleeding episodes. One patient had a transient WHO grade 4 increase in bilirubin, and four patients had a decrease in glomerular filtration rate below the normal limit; one of these patients developed a non-reversible renal insufficiency. Ten patients (24%) complained of dyspnoea of uncertain mechanism, possibly involving bronchoconstriction. There were one complete and seven partial responses among 40 assessable patients (20%, 95% confidence limits 9–36%). Median response duration was 31 weeks (range 11–83 weeks) and median survival time 31 weeks (range 2–171 weeks). The current combination of gemcitabine and vindesine does not appear to be promising for further examination because of the toxicity and somewhat disappointing activity. © 1999 Cancer Research Campaig

    A protein kinase Cβ inhibitor attenuates multidrug resistance of neuroblastoma cells

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    BACKGROUND: The acquisition of drug resistance is a major reason for poor outcome of neuroblastoma. Protein kinase C (PKC) has been suggested to influence drug resistance in cancer cells. The aim of this study was to elucidate whether inhibition of PKCβ isoforms influences drug-resistance of neuroblastoma cells. METHODS: The effect of the PKCβ inhibitor LY379196 on the growth-suppressing effects of different chemotherapeutics on neuroblastoma cells was analyzed with MTT assays. The effect of LY379196 on the accumulation of [(3)H]vincristine was also investigated RESULTS: The PKCβ inhibitor LY379196 suppressed the growth of three neuroblastoma cell lines. LY379196 also augmented the growth-suppressive effect of doxorubicin, etoposide, paclitaxel, and vincristine, but not of carboplatin. The effect was most marked for vincristine and for the cell-line (SK-N-BE(2)) that was least sensitive to vincristine. No effect was observed on the non-resistant IMR-32 cells. Two other PKC inhibitors, Gö6976 and GF109203X, also enhanced the vincristine effect. The PKC inhibitors caused an increased accumulation of [(3)H]vincristine in SK-N-BE(2) cells. CONCLUSIONS: This indicates that inhibition of PKCβ could attenuate multidrug resistance in neuroblastoma cells by augmenting the levels of natural product anticancer drugs in resistant cells

    Accounting Problems Under the Excess Profits Tax

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    DNA vaccines based on subunits from pathogens have several advantages over other vaccine strategies. DNA vaccines can easily be modified, they show good safety profiles, are stable and inexpensive to produce, and the immune response can be focused to the antigen of interest. However, the immunogenicity of DNA vaccines which is generally quite low needs to be improved. Electroporation and co-delivery of genetically encoded immune adjuvants are two strategies aiming at increasing the efficacy of DNA vaccines. Here, we have examined whether targeting to antigen-presenting cells (APC) could increase the immune response to surface envelope glycoprotein (Env) gp120 from Human Immunodeficiency Virus type 1 (HIV- 1). To target APC, we utilized a homodimeric vaccine format denoted vaccibody, which enables covalent fusion of gp120 to molecules that can target APC. Two molecules were tested for their efficiency as targeting units: the antibody-derived single chain Fragment variable (scFv) specific for the major histocompatilibility complex (MHC) class II I-E molecules, and the CC chemokine ligand 3 (CCL3). The vaccines were delivered as DNA into muscle of mice with or without electroporation. Targeting of gp120 to MHC class II molecules induced antibodies that neutralized HIV-1 and that persisted for more than a year after one single immunization with electroporation. Targeting by CCL3 significantly increased the number of HIV-1 gp120-reactive CD8(+) T cells compared to non-targeted vaccines and gp120 delivered alone in the absence of electroporation. The data suggest that chemokines are promising molecular adjuvants because small amounts can attract immune cells and promote immune responses without advanced equipment such as electroporation.Funding Agencies|Research Council of Norway; Odd Fellow</p

    The prevalence and experience of oral diseases in Adelaide nursing home residents

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    The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.Background: The twenty-first century will see the evolution of a population of dentate older Australians with dental needs very different from those of older adults in past years. This study provided comprehensive information concerning oral disease prevalence in older South Australian nursing home residents. Methods: This paper presents cross-sectional baseline results. Results: Most of the 224 residents, from seven randomly selected nursing homes, were functionally dependent, medically compromised, cognitively impaired and behaviourally difficult older adults who presented many complex challenges to carers and to dental professionals. Two-thirds (66 per cent) were edentulous with many dental problems and treatment needs. Dentate residents had a mean of 11.9 teeth present, higher than previously reported. The prevalence and experience of coronal and root caries and plaque accumulation was very high in dentate residents; especially males, those admitted more than three years previously, those who ate fewer food types and those who were severely cognitively impaired. These residents had more retained roots, decayed teeth and missing teeth, and fewer filled teeth when compared with data for community-dwelling older adults. Conclusions: This study highlighted the poor oral health status of these nursing home residents and the great impact of dementia on their high levels of oral diseases.JM Chalmers, C Hodge, JM Fuss, AJ Spencer, KD Carte

    Survey of patient satisfaction with the Breastfeeding Education and Support Services of The Royal Women's Hospital, Melbourne

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    <p>Abstract</p> <p>Background</p> <p>The Breastfeeding Education and Support Services (BESS) is a unit of The Royal Women's Hospital in Melbourne, Australia, staffed by International Board Certified Lactation Consultants (IBCLCs), providing day/short-stay and an outpatient clinic for mothers and infants with breastfeeding problems. It is important to measure women's experience of visiting the service as part of quality assurance. The aim of this project was to conduct an anonymous postal survey of clients' satisfaction with BESS.</p> <p>Methods</p> <p>An anonymous survey was posted on 16 November 2005 and again on 31 January 2006, to all women who had attended BESS in September 2005.</p> <p>Results</p> <p>The response rate was 60.5% (78/129). Eighty percent (62/78) of respondents attended day-stay, 33% (26/78) attended short-stay and 15% (12/78) attended the outpatient clinic. The percentage of women who responded "strongly agree" to the statement "Overall, I am satisfied with the services" was 49% (35/72) and 50% (6/12) for those who went to day/short-stay and the outpatient clinic respectively. Overall, 56% of all respondents responded that the quality of BESS was "better than expected". The most common breastfeeding problem reported was difficulty attaching the baby to the breast, followed by nipple damage, low milk supply and painful feeding.</p> <p>Conclusion</p> <p>BESS seems to have provided a satisfactory service to most clients. Most respondents were clearly satisfied with the support given by the IBCLCs and have also responded that the staff were professional and knowledgeable in their field of work.</p

    Spatially Resolved Distribution Function and the Medium-Range Order in Metallic Liquid and Glass

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    The structural description of disordered systems has been a longstanding challenge in physical science. We propose an atomic cluster alignment method to reveal the development of three-dimensional topological ordering in a metallic liquid as it undercools to form a glass. By analyzing molecular dynamic (MD) simulation trajectories of a Cu64.5Zr35.5 alloy, we show that medium-range order (MRO) develops in the liquid as it approaches the glass transition. Specifically, around Cu sites, we observe “Bergman triacontahedron” packing (icosahedron, dodecahedron and icosahedron) that extends out to the fourth shell, forming an interpenetrating backbone network in the glass. The discovery of Bergman-type MRO from our order-mining technique provides unique insights into the topological ordering near the glass transition and the relationship between metallic glasses and quasicrystals

    Spatial quantitation of drugs in tissues using liquid extraction surface analysis mass spectrometry imaging

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    Liquid extraction surface analysis mass spectrometry imaging (LESA-MSI) has been shown to be an effective tissue profiling and imaging technique, producing robust and reliable qualitative distribution images of an analyte or analytes in tissue sections. Here, we expand the use of LESA-MSI beyond qualitative analysis to a quantitative analytical technique by employing a mimetic tissue model previously shown to be applicable for MALDI-MSI quantitation. Liver homogenate was used to generate a viable and molecularly relevant control matrix for spiked drug standards which can be frozen, sectioned and subsequently analyzed for the generation of calibration curves to quantify unknown tissue section samples. The effects of extraction solvent composition, tissue thickness and solvent/tissue contact time were explored prior to any quantitative studies in order to optimize the LESA-MSI method across several different chemical entities. The use of a internal standard to normalize regional differences in ionization response across tissue sections was also investigated. Data are presented comparing quantitative results generated by LESA-MSI to LC-MS/MS. Subsequent analysis of adjacent tissue sections using DESI-MSI is also reported
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