58 research outputs found

    Measurements of top quark spin observables in tt events using dilepton final states in √s=8 TeV pp collisions with the ATLAS detector

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    Measurements of top quark spin observables in tt events are presented based on 20.2 fb(-1) of root s = 8TeV proton-proton collisions recorded with the ATLAS detector at the LHC. The analysis is performed in the dilepton final state, characterised by the presence of two isolated leptons ( electrons or muons). There are 15 observables, each sensitive to a different coefficient of the spin density matrix of tt production, which are measured independently. Ten of these observables are measured for the first time. All of them are corrected for detector resolution and acceptance effects back to the parton and stable-particle levels. The measured values of the observables at parton level are compared to Standard Model predictions at next-to-leading order in QCD. The corrected distributions at stable-particle level are presented and the means of the distributions are compared to Monte Carlo predictions. No significant deviation from the Standard Model is observed for any observable

    BMP axis in cancer cachexia

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    BACKGROUND Cancer cachexia is a devastating metabolic syndrome characterized by systemic inflammation and massive muscle and adipose tissue wasting. Although cancer cachexia is responsible for about 25% of cancer deaths, no effective therapies are available, and the underlying mechanisms have not been fully elucidated. Its occurrence complicates patients’ management, reduces tolerance to treatments and negatively affects patient quality of life. Muscle wasting, mainly due to increased protein breakdown rates, is one of the most prominent features of cachexia. Blocking muscle loss in cachexia mouse models dramatically prolongs survival even of animals in which tumor growth is not inhibited. Recent observations showed that bone morphogenetic protein (BMP) signaling, acting through Smad1, Smad5 and Smad8 (Smad1/5/8), is a master regulator of muscle homeostasis. BMP-Smad1/5/8 axis negatively regulates a novel ubiquitin ligase (MUSA1) required for muscle loss induced by denervation. MATERIALS AND METHODS First aim of the present work was to test if alterations of the BMP signaling pathway occur in cancer-induced muscle wasting in patients. For this purpose we checked the state of activation of the BMP pathway in muscle of cachectic vs non–cachectic patients affected by colon, pancreatic and esophagus cancer and in control subjects. We checked by Western Blot the phosphorylation levels of Smad1/5/8 and of Smad3 and by quantitative Real-Time PCR (qRT-PCR) the expression levels of different atrophy-related genes The second aim was to evaluate the degree of muscle atrophy and distribution of muscle fibers in patients and control subjects using morphometric and immunohistochemical analyses. We also performed analysis on distribution of NCAM positive muscle fibers to assess the effect of denervation on muscle tropism. RESULTS From December 2014 we collected 95 rectus abdominis muscle biopsies of cancer patients and 11 from control subjects. In line with the results we obtained in C26 mice model (a well-established cancer cachexia experimental model) Smad1/5/8 phosphorylation, readout of the state of activation of the BMP pathway, was nearly completely abrogated in the muscles of cancer cachectic patients compared to cancer non-cachectic ones. Interestingly, the level of phosphorylation of Smad3 was not significantly affected suggesting specific effects of cancer growth on BMP pathway. The expression levels of different atrophy-related genes including MUSA1 were induced in the cachectic muscles. Interestingly, several BMP related genes are also changing the expression during cancer growth. We also found a correlation between suppression of BMP pathway, expression of atrophy related genes and Noggin, known to block BMP pathway. Morphometric analysis shown that patients with cancer cachexia have smaller myofiber diameter (in particular fast type fibers) in comparison to age-matched controls. In skeletal muscle from cancer patients (either cachectic or non-cachectic) we detected a prevalence of flat shaped, angulated and severely atrophic myofibers (i.e. morphological features of denervated myofibers), big fiber-type grouping (i.e. typical hallmark of denervation/reinnervation events) and numerous NCAM positive myofibers (i.e. specific marker of denervation). CONCLUSIONS These findings are consistent with the hypothesis that BMP inhibition is permissive to cachexia onset. Since the reactivation of the BMP-dependent signaling and MUSA1 suppression was sufficient to prevent tumor-induced muscle atrophy in our C26 mouse model (data not shown), the present data suggest that the BMP axis can be an effective target for therapeutic approaches to counteract cachexia also in cancer patients. The results of morphometric and immunohistochemical studies collected till now may suggest that denervation contributes to myofiber atrophy in cancer cachexia

    Measurements of top-quark pair differential cross-sections in the eμ channel in pp collisions at √s=13 TeV using the ATLAS detector

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    This article presents measurements of tt¯ differential cross-sections in a fiducial phase-space region, using an integrated luminosity of 3.2 fb- 1 of proton–proton data at a centre-of-mass energy of s=13 TeV recorded by the ATLAS experiment at the LHC in 2015. Differential cross-sections are measured as a function of the transverse momentum and absolute rapidity of the top quark, and of the transverse momentum, absolute rapidity and invariant mass of the tt¯ system. The tt¯ events are selected by requiring one electron and one muon of opposite electric charge, and at least two jets, one of which must be tagged as containing a b-hadron. The measured differential cross-sections are compared to predictions of next-to-leading order generators matched to parton showers and the measurements are found to be consistent with all models within the experimental uncertainties with the exception of the Powheg-Box+ Herwig++ predictions, which differ significantly from the data in both the transverse momentum of the top quark and the mass of the tt¯ system

    Search for new resonances decaying to a W or Z boson and a Higgs boson in the ℓ+ℓ−bb¯, ℓνbb¯, and νν¯bb¯ channels with pp collisions at √s=13 TeV with the ATLAS detector

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    A search is presented for new resonances decaying to a W or Z boson and a Higgs boson in the ℓ+ℓ−bb¯, ℓνbb¯, and νν¯bb¯ channels in pp collisions at s=13 TeV with the ATLAS detector at the Large Hadron Collider using a total integrated luminosity of 3.2 fb−1. The search is conducted by looking for a localized excess in the WH/ZH invariant or transverse mass distribution. No significant excess is observed, and the results are interpreted in terms of constraints on a simplified model based on a phenomenological Lagrangian of heavy vector triplets

    Oocyte and ovarian tissue cryopreservation in European countries : statutory background, practice, storage and use

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    STUDY QUESTION: What is known in Europe about the practice of oocyte cryopreservation (OoC), in terms of current statutory background, funding conditions, indications (medical and ‘non-medical’) and specific number of cycles? SUMMARY ANSWER: Laws and conditions for OoC vary in Europe, with just over half the responding countries providing this for medical reasons with state funding, and none providing funding for ‘non-medical’ OoC. WHAT IS ALREADY KNOWN: The practice of OoC is a well-established and increasing practice in some European countries, but data gathering on storage is not homogeneous, and still sparse for use. Ovarian tissue cryopreservation (OtC) is only practiced and registered in a few countries. STUDY DESIGN, SIZE, AND DURATION: A transversal collaborative survey on OoC and OtC, was designed, based on a country questionnaire containing information on statutory or professional background and practice, as well as available data on ovarian cell and tissue collection, storage and use. It was performed between January and September 2015. PARTICIPANTS/MATERIALS, SETTING AND METHODS: All ESHRE European IVF Monitoring (EIM) consortium national coordinators were contacted, as well as members of the ESHRE committee of national representatives, and sent a questionnaire. The form included national policy and practice details, whether through current existing law or code of practice, criteria for freezing (age, health status), availability of funding and the presence of a specific register. The questionnaire also included data on both the number of OoC cycles and cryopreserved oocytes per year between 2010 and 2014, specifically for egg donation, fertility preservation for medical disease, ‘other medical’ reasons as part of an ART cycle, as well as for ‘non-medical reasons’ or age-related fertility decline. Another question concerning data on freezing and use of ovarian tissue over 5 years was added and sent after receiving the initial questionnaire. MAIN RESULTS AND THE ROLE OF CHANCE: Out of 34 EIM members, we received answers regarding OoC regulations and funding conditions from 27, whilst 17 countries had recorded data for OoC, and 12 for OtC. The specific statutory framework for OoC and OtC varies from absent to a strict frame. A total of 34 705 OoC cycles were reported during the 5-year-period, with a continuous increase. However, the accurate description of numbers was concentrated on the year 2013 because it was the most complete. In 2013, a total of 9126 aspirations involving OoC were reported from 16 countries. Among the 8885 oocyte aspirations with fully available data, the majority or 5323 cycles (59.9%) was performed for egg donation, resulting in the highest yield per cycle, with an average of 10.4 oocytes frozen per cycle. OoC indication was ‘serious disease’ such as cancer in 10.9% of cycles, other medical indications as ‘part of an ART cycle’ in 16.1%, and a non-medical reason in 13.1%. With regard to the use of OoC, the number of specifically recorded frozen oocyte replacement (FOR) cycles performed in 2013 for all medical reasons was 14 times higher than the FOR for non-medical reasons, using, respectively, 8.0 and 8.4 oocytes per cycle. Finally, 12 countries recorded storage following OtC and only 7 recorded the number of grafted frozen/thawed tissues. LIMITATIONS, REASONS FOR CAUTION: Not all countries have data regarding OoC collection, and some data came from voluntary collaborating centres, rather than a national authority or register. Furthermore, the data related to use of OoC were not included for two major players in the field, Italy and Spain, where numbers were conflated for medical and non-medical reasons. Finally, the number of cycles started with no retrieval is not available. Data are even sparser for OtC. WIDER IMPLICATIONS OF THE FINDINGS: There is a need for ART authorities and professional bodies to record precise data for practice and use of OoC (and OtC), according to indications and usage, in order to reliably inform all stakeholders including women about the efficiency of both methods. Furthermore, professional societies should establish professional standards for access to and use of OoC and OtC, and give appropriate guidance to all involved. STUDY FUNDING/COMPETING INTEREST(S): The study was supported by ESHRE. There are no conflicts of interest.peer-reviewe

    Search for single production of vector-like quarks decaying into Wb in pp collisions at s=8\sqrt{s} = 8 TeV with the ATLAS detector

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    Measurement of the charge asymmetry in top-quark pair production in the lepton-plus-jets final state in pp collision data at s=8TeV\sqrt{s}=8\,\mathrm TeV{} with the ATLAS detector

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    Charged-particle distributions at low transverse momentum in s=13\sqrt{s} = 13 TeV pppp interactions measured with the ATLAS detector at the LHC

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    ATLAS Run 1 searches for direct pair production of third-generation squarks at the Large Hadron Collider

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