1,721,423 research outputs found
Risk Stratification for in-Hospital Complications in Patients with Takotsubo Syndrome: the Geist Score
Full text linkIMPORTANCE: Takotsubo syndrome (TTS) is an acute reversible heart failure syndrome featured by significant rates of in-hospital complications (IHCs). There is a lack of data for risk stratification during hospitalization. OBJECTIVES: To derive a simple clinical score for risk prediction of IHCs in patients with TTS. DESIGN, SETTING, PARTECIPANTS: 1007 consecutive patients with TTS were enrolled in the GEIST (GErman and Italian STress Cardiomyopathy) registry. The score was developed using a stepwise multivariable regression analysis. The RE-TAKO (Spanish REgistry for TAKOtsubo cardiomyopathy) registry population (n=946 patients), also enrolling patients with TTS, was used for external score validation. MAIN OUTCOMES AND MEASURES: Four variables were identified as independent predictors of IHCs and were used for the score: male gender, history of neurological disorder, right ventricular involvement and left ventricular ejection fraction (LVEF). GEIST prognosis score was derived providing 20 points for male gender and history of neurological disorders, 30 points for right ventricle (RV) involvement, and subtracting the value in percent of LVEF. Score accuracy at ROC curve analysis 0.71, negative predictive power 87% in case of score values <20. External validation in the RETAKO population showed an area under the curve of 0.73 (p=n.s. vs GEIST derivation cohort). RESULTS: Overall rate of IHCs in the GEIST population was 23% % (death 4%, pulmonary edema 6%, invasive ventilation 6%, cardiogenic shock 9%). Stratification into 3 risk groups (<20 vs 20-40 and >40 points) classified 41% of patients as at low risk, 44% as intermediate, and 15% as high risk. The observed IHC rates were 13%, 24% and 59%, respectively (p for trend <0.001). After 2.6 years follow-up patients with IHCs showed higher rates of mortality (40% vs 10%, p=0.01). CONCLUSIONS AND RELEVANCE: the GEIST prognostic score, a simple tool based on four variables, may be useful in early risk stratification of TTS. High-risk TTS patients may require intensive care unit stay, meanwhile low risk TTS could be discharged within few days. IHCs in TTS patients may be associated with increased risk of mortality at long-term follow-up
Alcune considerazioni sulla evoluzione tecnologica degli impianti nel comparto agro-alimentare
No full textFunctional characterization of the pneumococcal Integrative Conjugative Element Tn5253
Full text linkIntegrative conjugative elements (ICEs) are responsible for pneumococcal genome evolution and more particularly for virulence and drug resistance acquisition. During
conjugation, ICEs transfer from a donor cell containing the genetic element to a recipient cell lacking it. ICEs insert into the bacterial genome, excise from it and form a
covalently closed circular intermediate which can integrate in a different genomic site and/or can integrate in a new genome upon conjugative transfer. Tn5253 is a composite
ICE of Streptococcus pneumoniae conferring resistance to tetracycline and chloramphenicol. The complete nucleotide sequence showed that it is 64,528 bp in size
and contains 79 ORFs, 41 of which could not be annotated. Two distinct genetic elements were found integrated in Tn5253: Tn5251 (18,033 bp), of the Tn916-Tn1545
family of CTs, and Ωcat(pC194) (7,627 bp), which could not conjugate, but was capable of intracellular mobility by homologous recombination. Ωcat(pC194) was
shown to contain a copy of the staphylococcal plasmid pC194 with a 93-bp deletion in the replication origin, to be flanked by two 1,169-bp direct repeats, and to excise from
Tn5253 producing a circular form of the element. The highest transfer frequency of Tn5253 was registered when Streptococcus pyogenes was the donor (6.7 x 10-3
transconjugants/donor). Upon conjugal transfer, Tn5253 was found to always integrate at a single chromosomal site. The target site (attB) was a 83-bp sequence in the rbg
gene of S. pneumoniae. Strains carrying Tn5253 all contained circular forms of the ICE in which the ends were joined by a 84-bp sequence (attTn). attB and attTn differed only
for an extra nucleotide in attTn. When integrated into the chromosome, Tn5253 was flanked by a copy of attB and a copy of attTn: invariably attB was adjacent to the left
end and attTn to the right, suggesting a polarization in the DNA integration process. In order to study the mechanism of integration into pneumococcal chromosome, we
constructed an attB mutant in which the first 63 nts were deleted and 5 nucleotide changes introduced in the remaining 20 nts. The resulting attB mutant was used as
Tn5253 recipient strain in mating experiments. Conjugation frequency of Tn5253 in the attB mutant recipient was considerably lower when compared to a standard recipient (4.8 x 10-7 vs 1.7 x 10-5 transconjugants per donor cell). Five novel Tn5253 alternative insertion sites were found located in: spr1713, coding for an alpha-galactosidase,
spr0540 (cell wall synthesis enzyme), spr1534 (substrate binding protein of an ABC sugar transporter), spr1983 (MFS protein) and spr0546 (nrd, putative nitroreductase).
Transfer of Tn5253 from alternative attB sites occurred at lower frequencies than wild type donor ranging from 2 x 10-7 to < 3.6 x 10-8. One transconjugant harboring 3 copies
of Tn5253 was able to transfer the ICE at a frequency 100-fold higher than wild type donor. Tn5253 has a strong preference for its primary insertion site, even when it is
mutated, but it can also integrate at different sites. The insertion site of Tn5253 affects its transposition rate, which is decreased or abolished when integrated in one of the
alternative attB
Development of new solutions for high voltage power supplies of Neutral Beam Injector for nuclear fusion experiments
Full text linkThe DTT test facility has the goal of solving one of the critical challenges in harnessing of nuclear fusion energy: the extraction of the heat generated by the fusion process for future fusion reactor.
This research is particularly relevant in view of DEMO, which will be the intermediate step between ITER and commercial power plants.
A significant portion of substantial additional heating power required will be supplied through Neutral Beam Injection.
This thesis focuses on the development of a high-voltage power supply for the Neutral Beam Injector of DTT, with particular emphasis on the challenge posed by handling arc breakdowns at the output of the converter.
The application of Modular Multilevel Converter technology is explored within the context of the Acceleration Grid Power Supply for the Neutral Beam Injector of DTT.
Such power supply produces a high voltage, and has demanding requirements in terms of voltage ripple, voltage regulation range and energy delivered to the arc.
The research investigates a specific topology designed to minimise the number of semiconductors.
The work includes the design of the converter, the development of a custom control scheme, and the verification of performance through numerical simulations.
Additionally, layout studies are conducted to have an initial estimate of the volume required for the installation of such converter.
Protection strategies against severe overvoltages, overcurrents and to limit the energy delivered to the arc during breakdown events are also evaluated
Exposure of farm workers to electromagnetic radiation from cellular network radio base stations situated on rural agricultural land
Full text linkThe electromagnetic field (EMF) levels generated by mobile telephone radio base stations (RBS) situated on rural-agricultural lands were assessed in order to evaluate the exposure of farm workers in the surrounding area. The expected EMF at various distances from a mobile telephone RBS was calculated using an ad hoc numerical forecast model. Subsequently, the electric fields around some RBS on agricultural lands were measured, in order to obtain a good approximation of the effective conditions at the investigated sites. The viability of this study was tested according to the Italian Regulations concerning general and occupational public exposure to time-varying EMFs. The calculated E-field values were obtained with the RBS working constantly at full power, but during the in situ measurements the actual power emitted by RBS antennas was lower than the maximum level, and the E-field values actually registered were much lower than the calculated values
Esposizione dei Lavoratori Agricoli in Prossimità di Stazioni Radio Base per Telefonia cellulare: Prime Valutazioni
No full textNella presente nota si riportano i risultati di uno studio mirato all’analisi del campo elettrico generato da Stazioni Radio Base posizionate su terreni agricoli allo scopo di valutare l’esposizione degli operatori durante le lavorazioni di campo effettuate in aree ad esse circostanti.
Per il rischio degli operatori si fa riferimento ai limiti di esposizione ed ai valori di attenzione (per permanenze non superiori alle quattro ore) riportati nel D.P.C.M. 08/07/2003 Art. 3 ovvero, per le frequenze a cui operano le SRB di telefonia cellulare, rispettivamente 20 V/m e 6 V/m.
Sulla base dei risultati ottenuti, si può affermare che esiste effettivamente un pericolo per la salute degli operatori che compiono lavori in prossimità di SRB per telefonia cellulare per un periodo superiore alle 4 ore; tale rischio, però, si riduce sensibilmente e diviene accettabile considerando le effettive condizioni di funzionamento delle Stazione Radio Base, notevomente inferiori a quelle nominali
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