1,458 research outputs found
Aortic valve surgery in patients who had undergone surgical myocardial revascularization previously.
OBJECTIVES:
A very high percentage of patients submitted to coronary artery bypass grafting (CABG) develop symptomatic aortic disease requiring surgery upon ageing. The surgical risk of the redo procedure is controversial. We describe our recent experience with patients submitted to this surgery under such conditions.
METHODS:
From July 1999 to July 2010, 51 patients (mean age, 70.3 ± 7.0 years, 86.3% male) submitted to CABG previously required aortic valve surgery (AVS). The mean interval between the surgeries was 7.1 ± 3.9 years. Twenty-one patients (41.2%) had also undergone AVS during the first surgery [12 patients (57.7%) had valve replacement and 9 patients (42.8%) had valvuloplasty]. At presentation, 51.0% were in New York Heart Association Class III/IV and the standard and logistic EuroSCOREs were 10.1 ± 2.5 and 20.9 ± 16.5%, respectively.
RESULTS:
Aortic valve replacement was performed in 48 patients (94.1%). Two patients had undergone a surgery for the closure of a peri-prosthetic leak and one patient a valvuloplasty. Thirteen patients (25.5%) needed to undergo additional cardiac procedures, including root enlargement (three patients, 5.9%). Valve surgery was performed with non-dissection of the internal thoracic artery graft, when patented, and antegrade cardioplegic arrest of other territories. Hospital and 30-day mortality rate was 2% (n = 1). The mean duration of hospital stay was 13.0 ± 11.1 days. The most frequent complication was arrhythmias - in 25.5% of the patients, and mostly due to atrial fibrillation (19.6%). Permanent pacemaker for A-V block was required in 5.9% of the cases, stroke was documented in two cases (3.9%) and early re-intervention was observed in two cases.
CONCLUSIONS:
Redo AVS performed in patients submitted to CABG previously results in mortality and morbidity rates that are much lower than what is expected, bringing clear benefits to the patients
Frozen and Invariant Quantum Discord under Local Dephasing Noise
In this chapter, we intend to explore and review some remarkable dynamical
properties of quantum discord under various different open quantum system
models. Specifically, our discussion will include several concepts connected to
the phenomena of time invariant and frozen quantum discord. Furthermore, we
will elaborate on the relation of these two phenomena to the non-Markovian
features of the open system dynamics and to the usage of dynamical decoupling
protocols.Comment: 29 pages, 8 figure
Use of a colonoscope for distal duodenal stent placement in patients with malignant obstruction
Background: Stent placement in the distal duodenum or proximal jejunum with a therapeutic gastroscope can be difficult, because of the reach of the endoscope, loop formation in the stomach, and flexibility of the gastroscope. The use of a colonoscope may overcome these problems. Objective: To report our experience with distal duodenal stent placement in 16 patients using a colonoscope. Methods: Multicenter, retrospective series of patients with a malignant obstruction at the level of the distal duodenum and proximal jejunum and treated by stent placement using a colonoscope. Main outcome measurements are technical success, ability to eat, complications, and survival. Results: Stent placement was technically feasible in 93% (15/16) of patients. Food intake improved from a median gastric outlet obstruction scoring system (GOOSS) score of 1 (no oral intake) to 3 (soft solids) (p = 0.001). Severe complications were not observed. One patient had persistent obstructive symptoms presumably due to motility problems. Recurrent obstructive symptoms were caused by tissue/tumor ingrowth through the stent mesh [n = 6 (38%)] and stent occlusion by debris [n = 1 (6%)]. Reinterventions included additional stent placement [n = 5 (31%)], gastrojejunostomy [n = 2 (12%)], and endoscopic stent cleansing [n = 1 (6%)]. Median survival was 153 days. Conclusion: Duodenal stent placement can effectively and safely be performed using a colonoscope in patients with an obstruction at the level of the distal duodenum or proximal jejunum. A colonoscope has the advantage that it is long enough and offers good endoscopic stiffness, which avoids looping in the stomach
Potential toxic elements in stream sediments, soils and waters in an abandoned radium mine (central Portugal)
The Alto da Várzea radium mine (AV) exploited ore and U-bearing minerals, such as autunite and torbernite. The mine was exploited underground from 1911 to 1922, closed in 1946 without restoration, and actually a commercial area is deployed. Stream sediments, soils and water samples were collected between 2008 and 2009. Stream sediments are mainly contaminated in As, Th, U and W, which is related to the AV radium mine. The PTEs, As, Co, Cr, Sr, Th, U, W, Zn, and electrical conductivity reached the highest values in soils collected inside the mine influence. Soils are contaminated with As and U and must not be used for any purpose. Most waters have pH values ranging from 4.3 to 6.8 and are poorly mineralized (EC = 41-186 µS/cm; TDS = 33-172 mg/L). Groundwater contains the highest Cu, Cr and Pb contents. Arsenic occurs predominantly as H2(AsO4)- and H(AsO4)2-. Waters are saturated in goethite, haematite and some of them also in lepidocrocite and ferrihydrite, which adsorbs As (V). Lead is divalent in waters collected during the warm season, being mobile in these waters. Thorium occurs mainly as Th(OH)3(CO3)-, Th(OH)2(CO3) and Th(OH)2(CO3) 22- , which increase water Th contents. Uranium occurs predominantly as UO2CO3, but CaUO2(CO3) 32- and CaUO2(CO3)3 also occur, decreasing its mobility in water. The waters are contaminated in NO2-, Mn, Cu, As, Pb and U and must not be used for human consumption and in agricultural activities. The water contamination is mainly associated with the old radium mine and human activities. A restoration of the mining area with PTE monitoring is necessary to avoid a public hazard.Thanks are due to Prof. Joao Coutinho for the determination of organic matter and cation exchange capacity in samples of stream sediments and soils and A. Rodrigues for the water analyses, EDM for some information on the Alto da Varzea mine area. This study had the support of Portuguese Fundacao para a Ciencia e Tecnologia (FCT), through the strategic projects UID/GEO/04035/2013 and UID/MAR/04292/2013 (MARE).info:eu-repo/semantics/publishedVersio
Bat lung epithelial cells show greater host species-specific innate resistance than MDCK cells to human and avian influenza viruses
Background
With the recent discovery of novel H17N10 and H18N11 influenza viral RNA in bats and report on high frequency of avian H9 seroconversion in a species of free ranging bats, an important issue to address is the extent bats are susceptible to conventional avian and human influenza A viruses.
Method
To this end, three bat species (Eidolon helvum, Carollia perspicillata and Tadarida brasiliensis) of lung epithelial cells were separately infected with two avian and two human influenza viruses to determine their relative host innate immune resistance to infection.
Results
All three species of bat cells were more resistant than positive control Madin-Darby canine kidney (MDCK) cells to all four influenza viruses. TB1-Lu cells lacked sialic acid α2,6-Gal receptors and were most resistant among the three bat species. Interestingly, avian viruses were relatively more replication permissive in all three bat species of cells than with the use of human viruses which suggest that bats could potentially play a role in the ecology of avian influenza viruses. Chemical inhibition of the JAK-STAT pathway in bat cells had no effect on virus production suggesting that type I interferon signalling is not a major factor in resisting influenza virus infection.
Conclusion
Although all three species of bat cells are relatively more resistant to influenza virus infection than control MDCK cells, they are more permissive to avian than human viruses which suggest that bats could have a contributory role in the ecology of avian influenza viruses
Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
The inclusive and dijet production cross-sections have been measured for jets
containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass
energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The
measurements use data corresponding to an integrated luminosity of 34 pb^-1.
The b-jets are identified using either a lifetime-based method, where secondary
decay vertices of b-hadrons in jets are reconstructed using information from
the tracking detectors, or a muon-based method where the presence of a muon is
used to identify semileptonic decays of b-hadrons inside jets. The inclusive
b-jet cross-section is measured as a function of transverse momentum in the
range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet
cross-section is measured as a function of the dijet invariant mass in the
range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets
and the angular variable chi in two dijet mass regions. The results are
compared with next-to-leading-order QCD predictions. Good agreement is observed
between the measured cross-sections and the predictions obtained using POWHEG +
Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet
cross-section. However, it does not reproduce the measured inclusive
cross-section well, particularly for central b-jets with large transverse
momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final
version published in European Physical Journal
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
Investigating the effectiveness and feasibility of exercise on microvascular reactivity and quality of life in systemic sclerosis patients: study protocol for a feasibility study
Background: Raynaud’s phenomenon is one of the first clinical manifestations observed in systemic sclerosis (SSc).
This microvasculature disorder affects mostly the digits in over 95% of SSc patients, significantly affecting their healthrelated
quality of life (HRQoL) and incurring higher hospital admissions and other healthcare costs. Exercise is known to
improve both micro- and macrovascular function – aerobic exercise and resistance training, separately or combined,
have been demonstrated to lead to significant vasculo-physiological improvements in conditions that present
vasculopathy. However, the effects of a combined exercise programme on microcirculation in SSc patients has yet to
be investigated. Therefore, the purpose of this study is to assess the effects of high-intensity interval training (HIIT)
combined with circuit resistance training on the microvascular function in the digital area of SSc patients.
Methods: This will be a randomised controlled, feasibility trial with two arms, wherein 30 patients with SSc in receipt
of medical treatment will be randomly assigned to usual care (medical treatment) or to a 12-week supervised exercise
programme. Patients in the exercise group will undertake two, 45-min sessions each week consisting of 30 min HIIT (30
s 100% peak power output/30 s passive recovery) on the arm crank ergometer and 15 min of upper body circuit
resistance training. Patients will be assessed before as well as at 3 and 6 months following randomisation. Primary
outcomes of the study will be recruitment and retention rate, intervention acceptability and adherence to the exercise
programme. Secondary outcomes include the digital area cutaneous microvascular function (laser Doppler fluximetry
combined with iontophoresis), physical fitness, functional ability, upper back transcutaneous oxygen tension, body
composition and quality of life (EQ-5D-5L). Selected interviews with a subsample of patients will be undertaken to
explore their experiences of having Raynaud’s phenomenon and the acceptability of the exercise intervention and
study procedures.
Discussion: Data from this study will be used to identify the feasibility of a combined exercise programme to be
implemented in SSc patients, the acceptability of the intervention and the study design, and to determine the effects
of exercise on the microvasculature. Overall, this study will provide sufficient data to inform and support a full
multicentre clinical trial
Evidence for the Higgs-boson Yukawa coupling to tau leptons with the ATLAS detector
Results of a search for H → τ τ decays are presented, based on the full set of proton-proton collision data recorded by the ATLAS experiment at the LHC during 2011 and 2012. The data correspond to integrated luminosities of 4.5 fb−1 and 20.3 fb−1 at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV respectively. All combinations of leptonic (τ → `νν¯ with ` = e, µ) and hadronic (τ → hadrons ν) tau decays are considered. An excess of events over the expected background from other Standard Model processes is found with an observed (expected) significance of 4.5 (3.4) standard deviations. This excess provides evidence for the direct coupling of the recently discovered Higgs boson to fermions. The measured signal strength, normalised to the Standard Model expectation, of µ = 1.43 +0.43 −0.37 is consistent with the predicted Yukawa coupling strength in the Standard Model
Expression of osterix Is Regulated by FGF and Wnt/β-Catenin Signalling during Osteoblast Differentiation
Osteoblast differentiation from mesenchymal cells is regulated by multiple signalling pathways.
Here we have analysed the roles of Fibroblast Growth Factor (FGF) and canonical
Wingless-type MMTV integration site (Wnt/β-Catenin) signalling pathways on zebrafish
osteogenesis. We have used transgenic and chemical interference approaches to manipulate
these pathways and have found that both pathways are required for osteoblast differentiation
in vivo. Our analysis of bone markers suggests that these pathways act at the same
stage of differentiation to initiate expression of the osteoblast master regulatory gene osterix
(osx). We use two independent approaches that suggest that osx is a direct target of these
pathways. Firstly, we manipulate signalling and show that osx gene expression responds
with similar kinetics to that of known transcriptional targets of the FGF and Wnt pathways.
Secondly, we have performed ChIP with transcription factors for both pathways and our
data suggest that a genomic region in the first intron of osx mediates transcriptional activation.
Based upon these data, we propose that FGF and Wnt/β-Catenin pathways act in part
by directing transcription of osx to promote osteoblast differentiation at sites of bone
formation
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