640 research outputs found

    Interferometric measurement of interhyperfine scattering lengths in 87^{87}Rb

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    We present interferometeric measurements of the f=1f=1 to f=2f=2 inter-hyperfine scattering lengths in a single-domain spinor Bose-Einstein condensate of 87^{87}Rb. The inter-hyperfine interaction leads to a strong and state-dependent modification of the spin-mixing dynamics with respect to a non-interacting description. We employ hyperfine-specific Faraday-rotation probing to reveal the evolution of the transverse magnetization in each hyperfine manifold for different state preparations, and a comagnetometer strategy to cancel laboratory magnetic noise. The method allows precise determination of inter-hyperfine scattering length differences, calibrated to intra-hyperfine scattering length differences. We report (a3(12)−a2(12))/(a2(1)−a0(1))=−1.27(15)(a_{3}^{(12)}-a_{2}^{(12)})/(a_{2}^{(1)}-a_{0}^{(1)})=-1.27(15) and (a1(12)−a2(12))/(a2(1)−a0(1))=−1.31(13)(a_{1}^{(12)}-a_{2}^{(12)})/(a_{2}^{(1)}-a_{0}^{(1)})=-1.31(13), limited by atom number uncertainty. With achievable control of atom number, we estimate precisions of ≈0.3% \approx 0.3\% should be possible with this technique

    Pre- and Post-Failure Experimental Bending Analysis of Glass Elements Coated by Aged Anti-Shatter Safety Films

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    The main goal of Anti-Shatter Films (ASFs) applications for structural glass is to create a barrier able to keep together fragments and minimize risk after any impulsive or static load that could lead glass to cracking. The influence of ASF properties on the flexural strength of coated glass elements is thus a relevant topic for safe design purposes, but still little investigated. To this aim, an experimental material investigation is presented in this paper, in order to achieve a good knowledge of common ASFs from a chemical point of view. Moreover, the deterioration of mechanical and adhesion characteristics for ASF samples subjected to different environmental conditions and accelerated ageing is also investigated, so as to simulate the effects of long-term exposure to high humidity (HU) or high temperature (HT). An experimental campaign carried out on 20 small scale ASF-coated glass specimens is finally presented, based on a three-point bending (3PB) test setup. The out-of-plane bending response of unaged or aged samples is performed by taking into account two different displacement-rate levels, to assess their performance and bending capacity under steady-static or impulsive loads. In both cases, the attention is given to the characterization of elastic and post-failure performances. Finally, support for the interpretation of experimental outcomes is derived from a simplified theoretical model of composite beam with partial connection, in order to estimate the shear stiffness of ASF adhesive components in the elastic stage

    Validation of the Clinical COPD questionnaire in Italian language

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    BACKGROUND: The development and validation study of the Clinical Chronic Obstructive Disease (COPD) Questionnaire (CCQ) has recently been published in this journal. The CCQ is the first questionnaire that incorporates both clinician and patient guideline goals in the clinical control evaluation of patients with COPD in general clinical practice. The aim of this study is the validation of the CCQ questionnaire in Italian, in specific pulmonary disease clinical practice. METHODS: Validity was tested on a population of healthy subjects and patients with COPD, using the Italian validated version of the Short Form Health Survey (SF-36) and guideline recommended routine measurement in COPD patients (FEV(1), FVC, BMI and functional dyspnoea). Test-retest reliability was tested by re-administering the CCQ after 2 weeks. Responsiveness was tested by re-administering the CCQ after three weeks of hospital pulmonary rehabilitation. Distance walked and Borg breathlessness rating were measured at the end of the six-minute walking test (6 MWT), before and after rehabilitation. RESULTS: Cross-sectional data were collected from 175 subjects (55 healthy; 40 mild-moderate, 50 severe and 25 very severe COPD). Cronbach's alpha was high (0.89). The CCQ scores in patients were significantly worse than in healthy subjects. The CCQ total score in patients with COPD was significantly worse in those with BMI < = 21. Significant correlations were found between the CCQ total score and domains of the SF-36 (rho = -0.43 to rho = -0.72). The correlation between the CCQ and FEV1 % predicted was rho = -0.57. The correlation between the CCQ and MRC was rho = 0.63. Test-retest reliability was determined in 112 subjects over a period of two weeks (Intra Class Coefficient = 0.99). Forty-six patients with COPD showed significant improvement in CCQ scores, distance-walked and Borg breathlessness rating after 3 weeks of pulmonary rehabilitation, indicating CCQ responsiveness. CONCLUSIONS: The CCQ is self-administered and has been specially developed to measure clinical control in patients with COPD. Data support its validity, reliability and responsiveness in Italian and in specific pulmonary disease clinical practice

    Bose-Einstein Condensate Comagnetometer

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    We describe a comagnetometer employing the f=1f=1 and f=2f=2 ground state hyperfine manifolds of a 87^{87}Rb spinor Bose-Einstein condensate as co-located magnetometers. The hyperfine manifolds feature nearly opposite gyromagnetic ratios and thus the sum of their precession angles is only weakly coupled to external magnetic fields, while being highly sensitive to any effect that rotates both manifolds in the same way. The f=1f=1 and f=2f=2 transverse magnetizations and azimuth angles are independently measured by non-destructive Faraday rotation probing, and we demonstrate a 44.0(8)dB44.0(8)\text{dB} common-mode rejection in good agreement with theory. We show how spin-dependent interactions can be used to inhibit 2→12\rightarrow 1 hyperfine relaxing collisions, extending to ∼1s\sim 1\text{s} the transverse spin lifetime of the f=1,2f=1,2 mixtures. The technique could be used in high sensitivity searches for new physics on sub-millimeter length scales, precision studies of ultra-cold collision physics, and angle-resolved studies of quantum spin dynamics

    Synthesis and Characterization of Pyrazole-Enriched Cationic Nanoparticles as New Promising Antibacterial Agent by Mutual Cooperation

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    A pyrazole derivative (CB1) was previously evaluated in vivo for various pharmacological activities (with the exception of antimicrobial effects), using DMSO as the administrative medium, mainly due to its water insolubility. Considering the global necessity for new antimicrobial agents, CB1 attracted our attention as a candidate to meet this need, mainly because the secondary amine group in its structure would make it possible to obtain its hydrochloride salt (CB1H), thus effortlessly solving its water-solubility drawbacks. In preliminary microbiologic investigations on Gram-negative and Gram-positive bacteria, CB1H displayed weak antibacterial effects on MDR isolates of Gram-positive species, nonetheless better than those displayed by the commonly-used available antibiotics. Therefore, aiming at improving such activity and extending the antibacterial spectrum of CB1H to Gram-negative pathogens, in this first work CB1 was strategically formulated in nanoparticles using a cationic copolymer (P7) previously developed by us, possessing potent broad-spectrum bactericidal activity. Using the nanoprecipitation method, CB1H-loaded polymer nanoparticles (CB1H-P7 NPs) were obtained, which were analyzed by attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy to confirm the successful loading. Additionally, CB1H-P7 NPs were fully characterized in terms of morphology, size, polydispersity indices, surface charge, DL%, and EE%, as well as release and potentiometric profiles
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