1,443 research outputs found

    Charge Management for Gravitational Wave Observatories using UV LEDs

    Full text link
    Accumulation of electrical charge on the end mirrors of gravitational wave observatories, such as the space-based LISA mission and ground-based LIGO detectors, can become a source of noise limiting the sensitivity of such detectors through electronic couplings to nearby surfaces. Torsion balances provide an ideal means for testing gravitational wave technologies due to their high sensitivity to small forces. Our torsion pendulum apparatus consists of a movable Au-coated Cu plate brought near a Au-coated Si plate pendulum suspended from a non-conducting quartz fiber. A UV LED located near the pendulum photoejects electrons from the surface, and a UV LED driven electron gun directs photoelectrons towards the pendulum surface. We have demonstrated both charging and discharging of the pendulum with equivalent charging rates of ∼\sim105e/s10^5 e/\mathrm{s}, as well as spectral measurements of the pendulum charge resulting in a white noise level equivalent to 3×105e/Hz3\times10^5 e/\sqrt{Hz}.Comment: 5 pages, submitted to PR

    Scattering into Cones and Flux across Surfaces in Quantum Mechanics: a Pathwise Probabilistic Approach

    Full text link
    We show how the scattering-into-cones and flux-across-surfaces theorems in Quantum Mechanics have very intuitive pathwise probabilistic versions based on some results by Carlen about large time behaviour of paths of Nelson diffusions. The quantum mechanical results can be then recovered by taking expectations in our pathwise statements.Comment: To appear in Journal of Mathematical Physic

    The Neoadjuvant Net: A patient- and surgeon-friendly device to facilitate safe breast-conserving surgery in patients who underwent neoadjuvant treatment

    Get PDF
    The primary goal of the study was to describe an innovative and helpful tool in defining the minimal surgical margins necessary during breast-conserving surgery (BCS) after neoadjuvant treatment: the Neoadjuvant Net (NN). The secondary endpoint was to assess its usefulness in achieving postoperative disease-free margins and reducing Ipsilateral Breast Tumor Recurrences (IBRTs). The breast-conserving surgical technique together with the use of the Neoadjuvant Net is herein reported. Age, stage at diagnosis, clinical and pathological response, lymph node status, type of surgery, margin status, and incidence of local and distant recurrence were retrospectively analyzed. Seventy-five patients underwent BCS following medical treatment from 2000 to 2011. The majority of the patients had significant size reduction (63/75, 84%). Twenty-two had a complete clinical response but only 11 (11/75, 14.7%) showed a complete pathological response. Two patients (2/75, 2.67%) had infiltrated surgical margins. After a mean follow-up of seventy months, 3 patients (3/75, 4%) had IBRTs and 4 women had distant metastases (4/75, 5.34%). The NN is an easy-to-use, non-invasive instrument designed with the purpose of facilitating the surgeon's task of reducing infiltrated margins and IBTRs

    Polymorphonuclear myeloid-derived suppressor cells limit antigen crosspresentation by dendritic cells in cancer

    Get PDF
    DCs are a critical component of immune responses in cancer primarily due to their ability to cross-present tumor-associated antigens. Cross-presentation by DCs in cancer is impaired, which may represent one of the obstacles for the success of cancer immunotherapies. Here, we report that polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) blocked crosspresentation by DCs without affecting direct presentation of antigens by these cells. This effect did not require direct cell-cell contact and was associated with transfer of lipids. Neutrophils (PMN) and PMN-MDSC transferred lipid to DCs equally well; however, PMN did not affect DC cross-presentation. PMN-MDSC generate oxidatively truncated lipids previously shown to be involved in impaired cross-presentation by DCs. Accumulation of oxidized lipids in PMN-MDSC was dependent on myeloperoxidase (MPO). MPO-deficient PMN-MDSC did not affect cross-presentation by DCs. Cross-presentation of tumor-associated antigens in vivo by DCs was improved in MDSC-depleted or tumor-bearing MPO-KO mice. Pharmacological inhibition of MPO in combination with checkpoint blockade reduced tumor progression in different tumor models. These data suggest MPO-driven lipid peroxidation in PMN-MDSC as a possible non–cell autonomous mechanism of inhibition of antigen cross-presentation by DCs and propose MPO as potential therapeutic target to enhance the efficacy of current immunotherapies for patients with cancer

    Tumors carrying BRAF-mutations over-express NAMPT that is genetically amplified and possesses oncogenic properties

    Get PDF
    Background: Nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme in nicotinamide adenine dinucleotide (NAD) biosynthesis, is up-regulated in several cancers, including metastatic melanoma (MM). The BRAF oncogene is mutated in different cancer types, among which MM and thyroid carcinoma (THCA) are prominent. Drugs targeting mutant BRAF are effective, especially in MM patients, even though resistance rapidly develops. Previous data have linked NAMPT over-expression to the acquisition of BRAF resistance, paving the way for therapeutic strategies targeting the two pathways. Methods: Exploiting the TCGA database and a collection of MM and THCA tissue microarrays we studied the association between BRAF mutations and NAMPT expression. BRAF wild-type (wt) cell lines were genetically engineered to over-express the BRAF V600E construct to demonstrate a direct relationship between over-activation of the BRAF pathway and NAMPT expression. Responses of different cell line models to NAMPT (i)nhibitors were studied using dose–response proliferation assays. Analysis of NAMPT copy number variation was performed in the TCGA dataset. Lastly, growth and colony forming assays were used to study the tumorigenic functions of NAMPT itself. Results: The first finding of this work is that tumor samples carrying BRAF-mutations over-express NAMPT, as demonstrated by analyzing the TCGA dataset, and MM and THC tissue microarrays. Importantly, BRAF wt MM and THCA cell lines modified to over-express the BRAF V600E construct up-regulated NAMPT, confirming a transcriptional regulation of NAMPT following BRAF oncogenic signaling activation. Treatment of BRAF-mutated cell lines with two different NAMPTi was followed by significant reduction of tumor growth, indicating NAMPT addiction in these cells. Lastly, we found that several tumors over-expressing the enzyme, display NAMPT gene amplification. Over-expression of NAMPT in BRAF wt MM cell line and in fibroblasts resulted in increased growth capacity, arguing in favor of oncogenic properties of NAMPT. Conclusions: Overall, the association between BRAF mutations and NAMPT expression identifies a subset of tumors more sensitive to NAMPT inhibition opening the way for novel combination therapies including NAMPTi with BRAFi/MEKi, to postpone and/or overcome drug resistance. Lastly, the over-expression of NAMPT in several tumors could be a key and broad event in tumorigenesis, substantiated by the finding of NAMPT gene amplification
    • …
    corecore