2,361 research outputs found
Experimental study of vapor-cell magneto-optical traps for efficient trapping of radioactive atoms
We have studied magneto-optical traps (MOTs) for efficient on-line trapping
of radioactive atoms. After discussing a model of the trapping process in a
vapor cell and its efficiency, we present the results of detailed experimental
studies on Rb MOTs. Three spherical cells of different sizes were used. These
cells can be easily replaced, while keeping the rest of the apparatus
unchanged: atomic sources, vacuum conditions, magnetic field gradients, sizes
and power of the laser beams, detection system. By direct comparison, we find
that the trapping efficiency only weakly depends on the MOT cell size. It is
also found that the trapping efficiency of the MOT with the smallest cell,
whose diameter is equal to the diameter of the trapping beams, is about 40%
smaller than the efficiency of larger cells. Furthermore, we also demonstrate
the importance of two factors: a long coated tube at the entrance of the MOT
cell, used instead of a diaphragm; and the passivation with an alkali vapor of
the coating on the cell walls, in order to minimize the losses of trappable
atoms. These results guided us in the construction of an efficient
large-diameter cell, which has been successfully employed for on-line trapping
of Fr isotopes at INFN's national laboratories in Legnaro, Italy.Comment: 9 pages, 7 figures, submitted to Eur. Phys. J.
Unsegmented long-term time-dependent modeling of the Nankai subduction zone (Japan)
The authors have recently presented a harmonized framework that unifies state-of-the-art methodologies for relaxing fault segmentation assumptions, including time-dependent earthquake occurrence and accounting for fault interaction. This framework has so far only been applied to shallow crustal faults, which are the typical focus of recent advancements in fault-based probabilistic seismic hazard analysis (PSHA). The methodological study presented in this paper is a first attempt to extend this framework to a subduction zone. The case study presented herein concerns the 900-km long Nankai subduction zone in South Japan. This work highlights several challenges with implementing the considered framework to subduction zones, emphasizing possible future research efforts that could improve the results presented in this study. In particular, it is concluded that (1) down-dip discretization of subduction zones should be used along with the along-strike discretization currently used for shallow crustal faults; (2) further research is needed to develop a standard physically-motivated approach to generate viable ruptures for subduction zones; (3) plate convergence rate and interplate coupling coefficients (i.e., heterogeneity of the coupling ratio defined as the slip rate divided by the plate convergence rate) should be explored and explicitly accounted for as part of the epistemic uncertainty in the hazard assessment; (4) 2D functions describing the shape of the average single-event slip should be developed
Penetrating particle ANalyzer (PAN)
PAN is a scientific instrument suitable for deep space and interplanetary
missions. It can precisely measure and monitor the flux, composition, and
direction of highly penetrating particles (100 MeV/nucleon) in deep
space, over at least one full solar cycle (~11 years). The science program of
PAN is multi- and cross-disciplinary, covering cosmic ray physics, solar
physics, space weather and space travel. PAN will fill an observation gap of
galactic cosmic rays in the GeV region, and provide precise information of the
spectrum, composition and emission time of energetic particle originated from
the Sun. The precise measurement and monitoring of the energetic particles is
also a unique contribution to space weather studies. PAN will map the flux and
composition of penetrating particles, which cannot be shielded effectively,
precisely and continuously, providing valuable input for the assessment of the
related health risk, and for the development of an adequate mitigation
strategy. PAN has the potential to become a standard on-board instrument for
deep space human travel.
PAN is based on the proven detection principle of a magnetic spectrometer,
but with novel layout and detection concept. It will adopt advanced particle
detection technologies and industrial processes optimized for deep space
application. The device will require limited mass (~20 kg) and power (~20 W)
budget. Dipole magnet sectors built from high field permanent magnet Halbach
arrays, instrumented in a modular fashion with high resolution silicon strip
detectors, allow to reach an energy resolution better than 10\% for nuclei from
H to Fe at 1 GeV/n
Effects of caspofungin against Candida guilliermondii and Candida parapsilosis.
The in vitro activity of caspofungin (CAS) was investigated against 28 yeast isolates belonging to Candida albicans (n = 5), Candida guilliermondii (n = 10), and Candida parapsilosis (n = 13). CAS MICs obtained by broth dilution and Etest methods clearly showed a rank order of susceptibility to the echinocandin compound with C. albicans > C. parapsilosis > C. guilliermondii. Similarly, time-kill assays performed on selected isolates showed that CAS was fungistatic against C. albicans and C. parapsilosis, while it did not exert any activity against C. guilliermondii. In a murine model of systemic candidiasis, CAS given at doses as low as 1 mg/kg of body weight/day was effective at reducing the kidney burden of mice infected with either C. albicans or C. guilliermondii isolates. Depending on the isolate tested, mice infected with C. parapsilosis responded to CAS given at 1 and/or 5 mg/kg/day. However, the overall CFU reduction for C. guilliermondii and C. parapsilosis was approximately 100-fold less than that for C. albicans. Our study shows that CAS was active in experimental systemic candidiasis due to C. guilliermondii and C. parapsilosis, but this activity required relatively high drug dosages
The transbonchial lung biopsy for diagnosis of diffuse parenchymal lung disease; Pro
The diagnosis of diffuse parenchymal lung disease (DPLD) may require invasive procedures after all noninvasive tools have failed. The clinical context in which these diseases develop and the radiological patterns are crucial for defining the timing and the methods to be used. After the introduction in clinical practice of HRCT scan, the evaluation of imaging patterns, along with the immunological status of the patient and the clinical course of the disease (acute vs. chronic) seem to be crucial to choose the best diagnostic procedure
Computed Tomography Predictors of Mortality or Disease Progression in Systemic Sclerosis–Interstitial Lung Disease: A Systematic Review
Objective: Although interstitial lung disease (ILD) is a major cause of morbidity and mortality in systemic sclerosis (SSc), its prognostication remains challenging. Given that CT represents the gold standard imaging technique in ILD assessment, a systematic review on chest CT findings as predictors of mortality or ILD progression in SSc-ILD was performed. Materials and Methods: Three databases (Medline, Embase, and Web of Science) were searched to identify all studies analyzing CT mortality or ILD progression predictors in SSc-ILD, from inception to December 2020. ILD progression was defined by worsening of forced vital capacity and/or CT ILD findings. Manuscripts not written in English, with not available full-text, not focusing on SSc-ILD or with SSc-ILD not extrapolated, otherwise with overlap syndromes, pediatric patients, <10 cases or predictors other than CT features were excluded. Results: Out of 3,513 citations, 15 full-texts (2,332 patients with SSc-ILD) met the inclusion criteria. ILD extent and extensive ILD, ILD densitometric analysis parameters, fibrotic extent and reticulation extent resulted as independent mortality predictors. Extensive ILD is also an independent predictor of death, need for supplemental oxygen or lung transplantation. Honeycombing extent is an independent risk factor for respiratory mortality. Independent predictors of ILD progression were not identified. Conclusions: ILD extent and extensive ILD independently predict mortality in SSc-ILD on CT, as well as ILD densitometric analysis, fibrotic extent and reticulation extent. Extensive ILD is also a predictor of death, need for supplemental oxygen, or lung transplantation. Honeycombing extent predicts respiratory mortality. CT predictors of ILD progression need to be further investigated. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/, PROSPERO, identifier: CRD420202005001
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