1,002 research outputs found
Teardown analysis of a ten cell bipolar nickel-hydrogen battery
Design studies have identified bipolar nickel-hydrogen batteries as an attractive storage option for high power, high voltage applications. A pre-prototype Ni-H2 battery was designed, assembled and tested in the early phases of a concept verification program. The initial stack was built with available hardware and components from past programs. The stack performed well. After 2000 low-earth-orbit cycles the stack was dismantled in order to allow evaluation and analysis of the design and components. The results of the teardown analysis and recommended modifications are discussed
Evidence-based practice needs stronger prognostic scores for the prediction of recurrent stroke.
Comment on:
Prediction of recurrent stroke and vascular death in patients with transient ischemic attack or nondisabling stroke: a prospective comparison of validated prognostic scores. [Stroke. 2010
Optimized search strategy for detecting scientifically strong studies on treatment through PubMed
Our study was designed to optimize the search strategies based on the work of Haynes et al. for detecting randomized controlled trials (RCTs) through PubMed. In particular, we aimed to improve precision for broad and narrow searches on interventional studies. We used in addition to the string suggested by the Hedge Team the following: {NOT ((animals [mh] NOT humans [mh]) OR (review [pt] OR meta-analysis [pt]))} and tested its effectiveness. The search was carried out on a year's worth of articles from the PubMed database. We analyzed 35,590 bibliographic citations about four relevant major topics in internal medicine (hypertension, diabetes, heart failure, and hepatitis). Precision, percentage gain between the Hedge Team search strategies and the new one were computed and reported in the text. Moreover, a pooled analysis was carried out in terms of absolute precision difference. We observed better precision for both broad and narrow searches. However, effective gain resulted only for broad searches. In this case, bibliographic citation recall effectively reduced (-24 to -35 % retrieved citation with a gain of 32-54 %) without loss of information. The search strategy improved broad searches regarding each of the four considered topics. We think this new search strategy, based on a previous work of the Hedge team, could be a step forward and can save some time by researchers
Artificial Intelligence Applications in Cardiovascular Magnetic Resonance Imaging: Are We on the Path to Avoiding the Administration of Contrast Media?
In recent years, cardiovascular imaging examinations have experienced exponential growth due to technological innovation, and this trend is consistent with the most recent chest pain guidelines. Contrast media have a crucial role in cardiovascular magnetic resonance (CMR) imaging, allowing for more precise characterization of different cardiovascular diseases. However, contrast media have contraindications and side effects that limit their clinical application in determinant patients. The application of artificial intelligence (AI)-based techniques to CMR imaging has led to the development of non-contrast models. These AI models utilize non-contrast imaging data, either independently or in combination with clinical and demographic data, as input to generate diagnostic or prognostic algorithms. In this review, we provide an overview of the main concepts pertaining to AI, review the existing literature on non-contrast AI models in CMR, and finally, discuss the strengths and limitations of these AI models and their possible future development
Heart involvement in Rheumatoid Arthritis: Systematic review and meta-analysis.
OBJECTIVE:
The aim of our study was to conduct a systematic review with meta-analysis of the current case-control studies about the valvular and pericardial involvement in patients with Rheumatoid Arthritis (RA), asymptomatic for cardiovascular diseases.
METHODS:
Case-control studies were identified by searching PubMed (1975-2010) and the Cochrane Central Register of Controlled Trials (CENTRAL) (1975-2010). Participants were adult patients with RA asymptomatic for cardiovascular diseases, and the outcome measure was the presence of cardiac involvement.
RESULTS:
Quantitative synthesis included 10 relevant studies out of 2326 bibliographic citations that had been found. RA resulted significantly associated to pericardial effusion (OR 10.7; 95% CI 5.0-23.0), valvular nodules (OR 12.5; 95% CI 2.8-55.4), tricuspidal valve insufficiency (OR 5.3; 95% CI 2.4-11.6), aortic valve stenosis (OR 5.2; 95% CI 1.1-24.1), mitral valve insufficiency (OR 3.4; 95% CI 1.7-6.7), aortic valve insufficiency (OR 1.7; 95% CI 1.0-2.7), combined valvular alterations (OR 4.3; 95% CI 2.3-8.0), mitral valve thickening and/or calcification (OR 5.0; 95% CI 2.0-12.7), aortic valve thickening and/or calcification (OR 4.4; 95% CI 1.1-17.4), valvular thickening and/or calcification (OR 4.8; 95% CI 2.2-10.5), and mitral valve prolapse (OR 2.2; 95% CI 1.2-4.0).
CONCLUSIONS:
Our systematic review pointed out the strength and the grade of both pericardial and cardiac valvular involvement in RA patients. Our findings underscore the importance of an echocardiographic assessment at least in clinical research when RA patients are involved. Moreover, further research is needed to understand the possible relationship of our findings and the increased cardiovascular mortality
A literature review and new data of trace metals fluxes from worldwide active volcanoes
Volcanic emissions are considered one of the major natural sources of several trace metals (e.g. As,
Cd, Cu, Pb, and Zn) to the atmosphere [Nriagu, 1989], and the geochemical cycles of these elements have to
be considered strongly influenced by volcanic input. However, the accurate estimation of the global volcanic
emissions of volatile trace metals into the atmosphere is still affected by a high level of uncertainty. The
latter depends on the large variability in the emission of the different volcanoes, and on their changing stage
of activity. Moreover, only few of the potential sources in the world have been directly measured [Hinkley et
al. 1999]. Atmospheric deposition processes (wet and dry) are the pathways through which volcanic
emissions return to the ground (soils, plants, aquifers), resulting in both harmful and beneficial effects
[Baxter et al. 1982; Aiuppa et al. 2000; Brusca et al. 2001; Delmelle, 2003; Bellomo et al. 2007; Martin et al.
2009; Floor et al. 2011; Calabrese et al. 2011].
In the first part of this study we present the results of a literature review on trace metals emissions
from active volcanoes around the world. In the second part, we present new data on the fluxes of the trace
metals from Etna (Italy) and four active volcanoes in the world: Turrialba (Costarica), Nyiragongo (DRC),
Mutnovsky and Gorely (Kamchatka).
We found 27 publications (the first dating back to the 70’s), 13 of which relate to the Etna and the
other include some of the world’s most active volcanoes: Mt. St. Helens, Erebus, Merapi, White Island,
Kilauea, Popocatepetl, Galeras, Indonesian arc, Satasuma and Masaya. The review shows that currently there
are very few data available, and that the most studied volcano is Mt. Etna. Using these data, we defined a
range of fluxes for As, Ba, Bi, Cd, Cu, Fe, Mn, Pb, Se, V and Zn (Figure 1).
To obtain new data we sampled
particulate filters at the five above
mentioned volcanoes. Filters were
mineralized (acid digestion) and
analyzed by ICP-MS. Sulphur to trace
element ratios were related to sulphur
fluxes to indirectly estimate trace
elements fluxes. Etna confirms to be
one of the greatest point sources in the
world. The Nyiragongo results to be
also a significant source of metals to the
atmosphere, especially considering its
persistent state of degassing from the
lava lake. Also Turrialba and Gorely
have high emission rates of trace metals
considering the global range. Only
Mutnovsky Volcano show values which
are sometimes lower than the range
obtained from the review, consistent
with the fact that it is mainly a
fumarolic field.
This work highlights the need to
expand the current dataset including
many other active volcanoes for a better
constraint of global trace metal fluxes
from active volcanoes
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