414 research outputs found

    Progress in Atomic Fountains at LNE-SYRTE

    Full text link
    We give an overview of the work done with the Laboratoire National de M\'etrologie et d'Essais-Syst\`emes de R\'ef\'erence Temps-Espace (LNE-SYRTE) fountain ensemble during the last five years. After a description of the clock ensemble, comprising three fountains, FO1, FO2, and FOM, and the newest developments, we review recent studies of several systematic frequency shifts. This includes the distributed cavity phase shift, which we evaluate for the FO1 and FOM fountains, applying the techniques of our recent work on FO2. We also report calculations of the microwave lensing frequency shift for the three fountains, review the status of the blackbody radiation shift, and summarize recent experimental work to control microwave leakage and spurious phase perturbations. We give current accuracy budgets. We also describe several applications in time and frequency metrology: fountain comparisons, calibrations of the international atomic time, secondary representation of the SI second based on the 87Rb hyperfine frequency, absolute measurements of optical frequencies, tests of the T2L2 satellite laser link, and review fundamental physics applications of the LNE-SYRTE fountain ensemble. Finally, we give a summary of the tests of the PHARAO cold atom space clock performed using the FOM transportable fountain.Comment: 19 pages, 12 figures, 5 tables, 126 reference

    Lpa1-5525 : a new lpa1 mutant isolated in a mutagenized population by a novel non-disrupting screening method

    Get PDF
    Phytic acid, or myo-inositol 1,2,3,4,5,6-hexakisphosphate, is the main storage form of phosphorus in plants. It is localized in seeds, deposited as mixed salts of mineral cations in protein storage vacuoles; during germination, it is hydrolyzed by phytases to make available P together with all the other cations needed for seed germination. When seeds are used as food or feed, phytic acid and the bound cations are poorly bioavailable for human and monogastric livestock due to their lack of phytase activity. Therefore, reducing the amount of phytic acid is one strategy in breeding programs aimed to improve the nutritional properties of major crops. In this work, we present data on the isolation of a new maize (Zea mays L.) low phytic acid 1 (lpa1) mutant allele obtained by transposon tagging mutagenesis with the Ac element. We describe the generation of the mutagenized population and the screening to isolate new lpa1 mutants. In particular, we developed a fast, cheap and non-disrupting screening method based on the different density of lpa1 seed compared to the wild type. This assay allowed the isolation of the lpa1-5525 mutant characterized by a new mutation in the lpa1 locus associated with a lower amount of phytic phosphorus in the seeds in comparison with the wild type

    Decontamination using a desiccant with air powder abrasion followed by biphasic calcium sulfate grafting: a new treatment for peri-implantitis.

    Get PDF
    Peri-implantitis is characterized by inflammation and crestal bone loss in the tissues surrounding implants. Contamination by deleterious bacteria in the peri-implant microenvironment is believed to be a major factor in the etiology of peri-implantitis. Prior to any therapeutic regenerative treatment, adequate decontamination of the peri-implant microenvironment must occur. Herein we present a novel approach to the treatment of peri-implantitis that incorporates the use of a topical desiccant (HYBENX), along with air powder abrasives as a means of decontamination, followed by the application of biphasic calcium sulfate combined with inorganic bovine bone material to augment the intrabony defect. We highlight the case of a 62-year-old man presenting peri-implantitis at two neighboring implants in positions 12 and 13, who underwent access flap surgery, followed by our procedure. After an uneventful 2-year healing period, both implants showed an absence of bleeding on probing, near complete regeneration of the missing bone, probing pocket depth reduction, and clinical attachment gain. While we observed a slight mucosal recession, there was no reduction in keratinized tissue. Based on the results described within, we conclude that the use of HYBENX and air powder abrasives, followed by bone defect grafting, represents a viable option in the treatment of peri-implantitis

    Left atrial function after atrial fibrillation cryoablation concomitant to minimally invasive mitral valve repair: A pilot study on long-term results and clinical implications

    Get PDF
    Background and Objectives: Surgical atrial fibrillation (AF) ablation concomitant to minimally invasive mitral valve repair has been proven to offer improved short- and long-term sinus rhythm (SR) maintenance compared to mitral valve surgery only. The objective of the present study was to explore, by thorough echocardiographic assessment, long-term morphological and functional left atrial (LA) outcomes after this combined surgical procedure. Materials and Methods: From October 2006 to November 2015, 48 patients underwent minimally invasive mitral valve repair and concomitant surgical AF cryoablation. Results: After 3.8 ± 2.2 years, 30 (71.4%) of those completing the follow-up (n = 42, 87.5%) presented SR. During follow-up, four (9.5%) patients suffered from cerebrovascular accidents and two of these subjects had a long-standing persistent AF relapse and were in AF at the time of the event, while the other two were in SR. An echocardiographic study focused on LA characteristics was performed in 29 patients (69.0%). Atrial morphology and function (e.g., maximal LA volume indexed to body surface area and total LA emptying fraction derived from volumes) in patients with stable SR (60.6 ± 13.1 mL/mq and 25.1 ± 7.3%) were significantly better than in those with AF relapses (76.8 ± 16.2 mL/mq and 17.5 ± 7.4%; respectively, p = 0.008 and p = 0.015). At follow-up, patients who suffered from ischemic cerebral events had maximal LA volume indexed to body surface area 61 ± 17.8 mL/mq, with total LA emptying fraction derived from volumes 23.6 ± 13.7%; patients with strokes in SR showed very enlarged LA volume (>70 mL/mq). Conclusions: AF cryoablation concomitant with minimally invasive mitral valve repair provides a high rate of SR maintenance and this relates to improved long-term morphological and functional LA outcomes. Further prospective studies are needed to define the cut-off values determining an increase in the risk for thromboembolic complications in patients with restored stable SR

    Experimenting an optical second with strontium lattice clocks

    Full text link
    Progress in realizing the SI second had multiple technological impacts and enabled to further constraint theoretical models in fundamental physics. Caesium microwave fountains, realizing best the second according to its current definition with a relative uncertainty of 2-4x10^(-16), have already been superseded by atomic clocks referenced to an optical transition, both more stable and more accurate. Are we ready for a new definition of the second? Here we present an important step in this direction: our system of five clocks connects with an unprecedented consistency the optical and the microwave worlds. For the first time, two state-of-the-art strontium optical lattice clocks are proven to agree within their accuracy budget, with a total uncertainty of 1.6x10^(-16). Their comparison with three independent caesium fountains shows a degree of reproducibility henceforth solely limited at the level of 3.1x10^(-16) by the best realizations of the microwave-defined second.Comment: 9 pages, 4 figures, 2 table

    Neuroendocrine carcinomas of the breast

    Get PDF
    INTRODUCTION: Neuroendocrine (NE) breast cancers encompass a heterogeneous group of tumours showing morphological features similar to those of NE neoplasms of the gut and lung and expressing one or more neuroendocrine markers (neuron specific enolase, chromogranins synaptophysin) in at least 50% of tumour cells. They are rare lesions representing about 2-3% of all breast cancers and affecting more frequently elderly patients. AIM: Prospective observational study is to analyse the clinico-pathological aspects of NE carcinomas of the breast undergone surgical resection compared to breast carcinomas with a minor neuroendocrine component and to conventional invasive ductal or lobular cancers. MATERIAL AND METHOD: Thirty-five consecutive breast carcinomas showing morphological features suggestive of an endocrine differentiation were selected among breast cancers undergone surgical treatment during the period of January 1979-December 2004. RESULTS: The 35 patients were divided into two categories: 13 neuroendocrine carcinomas (NECs) and 22 ductal carcinomas with a minor neuroendocrine component (DC-NE). The average follow-up was 60 months. The patients with CNE developed breast cancer in an advanced age compared to the patients with infiltrating ductal carcinoma NAS or infiltrating lobular carcinoma. We did not find recurrent disease in the NEC group, while it was observed in 2 patients (9%) with DC-NE, in 6 cases (17%) with infiltrating ductal carcinoma NAS and in 7 cases (20%) with infiltrating lobular carcinoma. DISCUSSION: The CNE compared with the infiltrating ductal and lobular carcinoma are statistically different in relation to the expression of the receptor of c-erb-B2, p53, progesterone, for the lymph node state at diagnosis and the risk of reappearance of breast tumour. Our study confirms the choice to consider the neuroendocrine carcinoma of the breast as a separate histological group and seems to suggest a less aggressiveness of this type of tumou

    Predictors of Bone Metastases at68Ga-PSMA-11 PET/CT in Hormone-Sensitive Prostate Cancer (HSPC) Patients with Early Biochemical Recurrence or Persistence

    Get PDF
    Prostate-specific-membrane-antigen/positron-emission-tomography (PSMA-PET) can accurately detect disease localizations in prostate cancer (PCa) patients with early biochemical recurrence/persistence (BCR/BCP), allowing for more personalized image-guided treatments in oligometastatic patients with major impact in the case of bone metastases (BM). Therefore, this study aimed to identify predictors of BM at PSMA-PET in early-BCR/BCP hormone-sensitive PCa (HSPC) patients, previously treated with radical intent (radiotherapy or radical prostatectomy ± salvage-radiotherapy (SRT)). A retrospective analysis was performed on 443 (68)Ga-PSMA-11-PET/CT scans. The cohort median PSA at PET-scan was 0.60 (IQR: 0.38–1.04) ng/mL. PSMA-PET detection rate was 42.0% (186/443), and distant lesions (M1a/b/c) were found in 17.6% (78/443) of cases. BM (M1b) were present in 9.9% (44/443) of cases, with 70.5% (31/44) showing oligometastatic spread (≀3 PSMA-positive lesions). In the multivariate binary logistic regression model (accuracy: 71.2%, Nagelkerke-R(2): 13%), T stage ≄ 3a (OR: 2.52; 95% CI: 1.13–5.60; p = 0.024), clinical setting (previous SRT vs. first-time BCR OR: 2.90; 95% CI: 1.32–6.35; p = 0.008), and PSAdt (OR: 0.93; 95% CI: 0.88–0.99; p = 0.026) were proven to be significant predictors of bone metastases, with a 7% risk increment for each single-unit decrement of PSAdt. These predictors could be used to further refine the indication for PSMA-PET in early BCR/BCP HSPC patients, leading to higher detection rates of bone disease and more personalized treatments
    • 

    corecore