Realization of the farad from the dc quantum Hall effect with digitally-assisted impedance bridges

A new traceability chain for the derivation of the farad from dc quantum Hall effect has been implemented at INRIM. Main components of the chain are two new coaxial transformer bridges: a resistance ratio bridge, and a quadrature bridge, both operating at 1541 Hz. The bridges are energized and controlled with a polyphase direct-digital-synthesizer, which permits to achieve both main and auxiliary equilibria in an automated way; the bridges and do not include any variable inductive divider or variable impedance box. The relative uncertainty in the realization of the farad, at the level of 1000 pF, is estimated to be 64E-9. A first verification of the realization is given by a comparison with the maintained national capacitance standard, where an agreement between measurements within their relative combined uncertainty of 420E-9 is obtained.Comment: 15 pages, 11 figures, 3 table

Connexin 26 Expression in Mammalian Cardiomyocytes

Connexins are a family of membrane-spanning proteins named according to their molecular weight. They are known to form membrane channels mediating cell-cell communication, which play an essential role in the propagation of electrical activity in the heart. Cx26 has been described in a number of tissues but not in the heart, and its mutations are frequently associated with deafness and skin diseases. The aim of this study was to assess the possible Cx26 expression in heart tissues of different mammalian species and to demonstrate its localization at level of cardiomyocytes. Samples of pig, human and rat heart and H9c2 cells were used for our research. Immunohistochemical and molecular biology techniques were employed to test the expression of Cx26. Interestingly, this connexin was found in cardiomyocytes, at level of clusters scattered over the cell cytoplasm but not at level of the intercalated discs where the other cardiac connexins are usually located. Furthermore, the expression of Cx26 in H9c2 myoblast cells increased when they were differentiated into cardiac-like phenotype. To our knowledge, the expression of Cx26 in pig, human and rat has been demonstrated for the first time in the present paper

Association of pre-operative interleukin-6 levels with Interagency Registry for Mechanically Assisted Circulatory Support profiles and intensive care unit stay in left ventricular assist device patients

BACKGROUND: Inflammatory mechanisms are associated with worse prognosis in end-stage heart failure (ESHF) patients who require left ventricular assist device (LVAD) support. Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profiles describe patient condition at pre-implant and outcome. This study assessed the relationship among inflammation patterns and INTERMACS profiles in LVAD recipients. METHOD: Thirty ESHF patients undergoing LVAD implantation as bridge to transplant were enrolled. Blood and urine samples were collected pre-operatively and serially up to 2 weeks post-operatively for assessment of inflammatory markers (plasma levels of interleukin [IL]-6, IL-8, IL-10, and osteopontin, a cardiac inflammatory-remodeling marker; and the urine neopterin/creatinine ratio, a monocyte activation marker). Multiorgan function was evaluated by the total sequential organ failure assessment (tSOFA) score. Outcomes of interest were early survival, post-LVAD tSOFA score, and intensive care unit (ICU) length of stay. RESULTS: Fifteen patients had INTERMACS profiles 1 or 2 (Group A), and 15 had profiles 3 or 4 (Group B). At pre-implant, only IL-6 levels and the IL-6/IL-10 ratio were higher in Group A vs B. After LVAD implantation, neopterin/creatinine ratio and IL-8 levels increased more in Group A vs B. Osteopontin levels increased significantly only in Group B. The tSOFA score at 2 weeks post-LVAD and ICU duration were related with pre-implant IL-6 levels. CONCLUSIONS: The INTERMACS profiles reflect the severity of the pre-operative inflammatory activation and the post-implant inflammatory response, affecting post-operative tSOFA score and ICU stay. Therefore, inflammation may contribute to poor outcome in patients with severe INTERMACS profile

Progress towards an accurate determination of the Boltzmann constant by Doppler spectroscopy

In this paper, we present significant progress performed on an experiment dedicated to the determination of the Boltzmann constant, k, by accurately measuring the Doppler absorption profile of a line in a gas of ammonia at thermal equilibrium. This optical method based on the first principles of statistical mechanics is an alternative to the acoustical method which has led to the unique determination of k published by the CODATA with a relative accuracy of 1.7 ppm. We report on the first measurement of the Boltzmann constant by laser spectroscopy with a statistical uncertainty below 10 ppm, more specifically 6.4 ppm. This progress results from improvements in the detection method and in the statistical treatment of the data. In addition, we have recorded the hyperfine structure of the probed saQ(6,3) rovibrational line of ammonia by saturation spectroscopy and thus determine very precisely the induced 4.36 (2) ppm broadening of the absorption linewidth. We also show that, in our well chosen experimental conditions, saturation effects have a negligible impact on the linewidth. Finally, we draw the route to future developments for an absolute determination of with an accuracy of a few ppm.Comment: 22 pages, 11 figure

Vitamin d plasma levels and in-hospital and 1-year outcomes in acute coronary syndromes : a prospective study

Deficiency in 25-hydroxyvitamin D (25[OH]D), the main circulating form of vitamin D in blood, could be involved in the pathogenesis of acute coronary syndromes (ACS). To date, however, the possible prognostic relevance of 25 (OH)D deficiency in ACS patients remains poorly defined. The purpose of this prospective study was to assess the association between 25 (OH)D levels, at hospital admission, with in-hospital and 1-year morbidity and mortality in an unselected cohort of ACS patients.We measured 25 (OH)D in 814 ACS patients at hospital presentation. Vitamin D serum levels >30\u200ang/mL were considered as normal; levels between 29 and 21\u200ang/mL were classified as insufficiency, and levels\u200a<\u200a20\u200ang/mL as deficiency. In-hospital and 1-year outcomes were evaluated according to 25 (OH)D level quartiles, using the lowest quartile as a reference.Ninety-three (11%) patients had normal 25 (OH)D levels, whereas 155 (19%) and 566 (70%) had vitamin D insufficiency and deficiency, respectively. The median 25 (OH)D level was similar in ST-elevation myocardial infarction (STEMI) and non-ST-elevation myocardial infarction (NSTEMI) patients (14.1 [IQR 9.0-21.9] ng/mL and 14.05 [IQR 9.1-22.05] ng/mL, respectively; P\u200a=\u200a.88). The lowest quartile of 25 (OH)D was associated with a higher risk for several in-hospital complications, including mortality. At a median follow-up of 366 (IQR 364-379) days, the lowest quartile of 25 (OH)D, after adjustment for the main confounding factors, remained significantly associated to 1-year mortality (P\u200a<\u200a.01). Similar results were obtained when STEMI and NSTEMI patients were considered separately.In ACS patients, severe vitamin D deficiency is independently associated with poor in-hospital and 1-year outcomes. Whether low vitamin D levels represent a risk marker or a risk factor in ACS remains to be elucidated

How do cardiologists select patients for dual antiplatelet therapy continuation beyond 1 year after a myocardial infarction? Insights from the EYESHOT Post-MI Study

Background: Current guidelines suggest to consider dual antiplatelet therapy (DAPT) continuation for longer than 12 months in selected patients with myocardial infarction (MI). Hypothesis: We sought to assess the criteria used by cardiologists in daily practice to select patients with a history of MI eligible for DAPT continuation beyond 1 year. Methods: We analyzed data from the EYESHOT Post-MI, a prospective, observational, nationwide study aimed to evaluate the management of patients presenting to cardiologists 1 to 3 years from the last MI event. Results: Out of the 1633 post-MI patients enrolled in the study between March and December 2017, 557 (34.1%) were on DAPT at the time of enrolment, and 450 (27.6%) were prescribed DAPT after cardiologist assessment. At multivariate analyses, a percutaneous coronary intervention (PCI) with multiple stents and the presence of peripheral artery disease (PAD) resulted as independent predictors of DAPT continuation, while atrial fibrillation was the only independent predictor of DAPT interruption for patients both at the second and the third year from MI at enrolment and the time of discharge/end of the visit. Conclusions: Risk scores recommended by current guidelines for guiding decisions on DAPT duration are underused and misused in clinical practice. A PCI with multiple stents and a history of PAD resulted as the clinical variables more frequently associated with DAPT continuation beyond 1 year from the index MI

Social Work Education: Innovations and Experiences

As confirmed by several of the articles proposed for this section, educators and researchers have stepped up their efforts reshaping traditional setting, activities and tools of teaching and learning and capturing evidence from practice to better understand potential and limits of this unedited condition. Among lessons learnt, the virtual environment produces effects on who learns but also on who teaches, and the virtual educational strategies can be effective only within a relational framework, in order to integrate the educational activities in the presence, not to replace it. Social work education are processes that develop through human relationships

Thoughts on a changing SI

The trend towards an International System of Units (SI) based on fundamental constants has been confirmed and recent actions could result in the redefinition of the four units still necessary to cover all the quantities of interest for physics and chemistry. In this paper some issues whose solution is becoming critical with the approach of the General Conference on Weights and Measures (CGPM) of 2011 are discussed. The traditional kinds of definition and the new proposals are considered on the basis of their mathematical expressions and the advantageous features of the most advanced proposal are pointed out. The problem of choosing the set of fundamental constants to be adopted as reference quantities for the SI units is addressed and a general rule for verifying that the set is sufficient and non-redundant is pointed out in the form of a linear system giving also expressions of all the units as functions of the reference constants. A partial application to the most important units and different sets of constants offers some comparative criteria and shows the advantages of a set including both h and me. A general condition to be fulfilled by an experiment in order to realize an SI unit is given and a procedure suitable to optimize the availability of the best relization on a global basis is outlined. Finally, the dissemination process is analysed to show that the implied comparisons of standards at any level are not affected by the realization uncertainty, so that the process can be continued with the same standards, independently of any change in the basic reference quantities of the unit system