144 research outputs found
Tests of electron flavor conservation with the Sudbury Neutrino Observatory
We analyze tests of electron flavor conservation that can be performed at the
Sudbury Neutrino Observatory (SNO). These tests, which utilize B solar
neutrinos interacting with deuterium, measure: 1) the shape of the recoil
electron spectrum in charged-current (CC) interactions (the CC spectrum shape);
and 2) the ratio of the number of charged current to neutral current (NC)
events (the CC/NC ratio). We determine standard model predictions for the CC
spectral shape and for the CC/NC ratio, together with realistic estimates of
their errors and the correlations between errors. We consider systematic
uncertainties in the standard neutrino spectrum and in the charged-current and
neutral current cross-sections, the SNO energy resolution and absolute energy
scale, and the SNO detection efficiencies. Assuming that either matter-enhanced
or vacuum neutrino oscillations solve the solar neutrino problems, we calculate
the confidence levels with which electron flavor non-conservation can be
detected using either the CC spectrum shape or the CC/NC ratio, or both. If the
SNO detector works as expected, the neutrino oscillation solutions that
best-fit the results of the four operating solar neutrino experiments can be
distinguished unambiguously from the standard predictions of electron flavor
conservation.Comment: 31 pages (RevTeX) + 10 figures (postscript). Requires epsfig.sty.
Gzipped figures also available at ftp://ftp.sns.ias.edu/pub/lisi/snopaper .
To appear in Phys. Rev.
Effects of the Tucson-Melbourne three-nucleon force in the proton-deuteron breakup process at Ep = 65 MeV
We present the calculated cross sections and vector analyzing powers using the Bonn B nucleon-nucleon potential and the Tucson-Melbourne three-nucleon force (3NF) for six collinearity and quasi-free scattering breakup configurations. These calculations are compared to the results of the recent kinematically complete pd experiments at Ep = 65 MeV. The Tucson-Melbourne 3NF, adjusted together with the Bonn B potential to reproduce the triton binding energy, leads to small effects both in cross sections and analyzing powers in all six studied configurations
Prospective long-term evaluation of incomplete distal renal tubular acidosis in idiopathic calcium nephrolithiasis diagnosed by low-dose NH4CL loading - gender prevalences and impact of alkali treatment
Purpose: Prospective evaluation of the prevalence of incomplete distal renal tubular acidosis (idRTA) in idiopathic calcium stone formers (ICSF) diagnosed by half-dose ammonium chloride loading (NH4Cl, 0.05 g/kg body weight/day) and impact of alkali treatment of idRTA.
Methods: Evaluation of 386 consecutive idiopathic calcium stone formers (ICSF) (280 males, 106 females) for idRTA. If screening fasting urine pH was > 5.80, 1-day NH4Cl loading was performed without severe adverse effects. Normally, urine pH falls below 5.45.
Results: Sixty-four idiopathic calcium stone formers exhibited idRTA, one complete dRTA. Prevalence was higher in women (25.4%) than in men (13.6%). Thus, for more equilibrated comparisons, we formed pairs of 62 idiopathic calcium stone formers (ICSF) with and 62 without idRTA, matched for gender, age, BMI and serum creatinine. Idiopathic calcium stone formers with idRTA more often had hypercalciuria (p < 0.025) and urine citrate < 2 mmol/d (p < 0.05), formed calcium phosphate stones more frequently, exhibited higher numbers of stones/year (1.4 ± 1.5 vs. 0.9 ± 0.8, p = 0.034) and 2.5 times more intrarenal calcifications (4.6 ± 5.9 vs. 1.8 ± 3.6, p = 0.002). All idiopathic calcium stone formers with idRTA were recommended chronic alkali therapy. After 4-15 years of follow-up, stone events /years follow-up (stone passage or urologic intervention) were higher in patients non-adherent to alkali therapy (0.61 ± 0.92) than in patients adherent to treatment (0.11 ± 0.21, p = 0.006).
Conclusion: Incomplete distal renal tubular acidosis is 1.8-fold more prevalent among female idiopathic calcium stone formers, predicts more stone recurrences, predisposes to calcium phosphate stones and is associated with 2.5 times more intrarenal calcifications vs. non-idRTA patients. Chronic alkali treatment reduces clinical stone recurrences by 5.5 times.
Keywords: Effects of alkali treatment; Gender prevalences; Incomplete distal renal tubular acidosis in idiopathic calcium nephrolithiasis; Intrarenal calcifications; Nephrocalcinosis
A case series of rare pathologies of the aorta and the aortic arch in adolescents and younger adults: Transfer of experience for an individualized approach
Objective: While aneurysm of the aortic root, interrupted aortic arch, and aortic coarctation are the most frequent aortic diseases in adolescents and younger adults, there are a number of rare pathologies of the thoracic aorta that need individualized treatment.
Patients: We present a small case series of unusual aortic pathologies in patients presenting with a broad spectrum of symptoms: tiredness, dysphagia, dyspnea, arterial hypertension, renal failure, and claudication. (1). Segmental agenesia of the descending aorta. (2). Balanced double aortic arch with complete vascular ring. (3). Right descending aortic arch, left lusorian artery with Kommerell diverticulum. (4). Large patent ductus (2.5 cm) and ventricular septal defect. (5). Aneurysm of the aortic arch in the presence of tuberous sclerosis. (6). Pseudo-aneurysm of the proximal descending aorta following coarctation patch plasty. (7). Supravalvular aortic stenosis combined with severe aortic valve stenosis. (8). Pseudo-aneurysm following ascendens-to-descendens bypass because of recurrent coarctation. (9). Takayasu arteriitis with severe stenosis in the thoraco-abdominal aorta.
Results: The following procedures were performed, using individualized cardiopulmonary bypass, canulation and cerebral protection strategies. (1). Ascending to supraceliac extra-anatomic bypass. (2). Division of the ductus ligament and of the anterior aortic arch distally to the left subclavian artery. (3). Excision of the Kommerell diverticulum and translocation of the left subclavian artery. (4). Patch closure of the aorto-pulmonary window (patent ductus) and closure of the ventricular septal defect. (5). Complete aortic arch replacement combined with debranching of the supra-aortic vessels. (6). Graft interposition of the proximal descending aorta. (7). Enlargement of the ascending aorta and aortic valve replacement. (8). Exclusion of the pseudo-aneurysm, end-to-side graft interposition. (9). Ascending aorta to infrarenal aorta or ascending to bi-iliac artery bypass (planned). All patients were operated on without operative mortality. One patient died in-hospital from pulmonary complications one week after surgery. One patient is still awaiting surgery. All other patients recovered very well from the operation and did not show any residual symptoms.
Conclusion: Rare pathologies of the thoracic aorta in younger patients may cause a broad spectrum of unusual symptoms; in some of them, diagnosis is delayed. Cross-sectional imaging is mandatory for optimal operative planning Surgical treatment can be performed with very satisfying results. The prognosis of these patients is usually favorable following surgery.
Keywords: adolescents; aortic arch; ascending aorta; cerebral protection; circulatory arrest; results; surgery; younger adults
The two-nucleon system at next-to-next-to-next-to-leading order
We consider the two-nucleon system at next-to-next-to-next-to-leading order
(N^3LO) in chiral effective field theory. The two-nucleon potential at N^3LO
consists of one-, two- and three-pion exchanges and a set of contact
interactions with zero, two and four derivatives. In addition, one has to take
into account various isospin-breaking and relativistic corrections. We employ
spectral function regularization for the multi-pion exchanges. Within this
framework, it is shown that the three-pion exchange contribution is negligibly
small. The low-energy constants (LECs) related to pion-nucleon vertices are
taken consistently from studies of pion-nucleon scattering in chiral
perturbation theory. The total of 26 four-nucleon LECs has been determined by a
combined fit to some np and pp phase shifts from the Nijmegen analysis together
with the nn scattering length. The description of nucleon-nucleon scattering
and the deuteron observables at N^3LO is improved compared to the one at NLO
and NNLO. The theoretical uncertainties in observables are estimated based on
the variation of the cut-offs in the spectral function representation of the
potential and in the regulator utilized in the Lippmann-Schwinger equation.Comment: 62 pp, 13 fig
What does an explanted PASCAL device look like?
We report the case of a 78-year-old female patient who had a PASCAL device implanted for severe degenerative mitral regurgitation. Intraprocedural echocardiography revealed persistent severe mitral regurgitation due to device dislocation. Implanting another device was not possible. After 8 days, the device was explanted, and the valve was replaced with a biological pro
We report the case of a 78-year-old female patient who had a PASCAL device implanted for severe degenerative mitral regurgitation. Intraprocedural echocardiography revealed persistent severe mitral regurgitation due to device dislocation. Implanting another device was not possible. After 8 days, the device was explanted, and the valve was replaced with a biological prosthesis. The PASCAL device and resected mitral valve leaflets were sent for histopathological workup.
Keywords: Mitral regurgitation; PASCAL device; Transcatheter therapysthesis. The PASCAL device and resected mitral valve leaflets were sent for histopathological workup
Concomitant Coronary Artery Bypass in Patients with Acute Type A Aortic Dissection
Coronary Artery Bypass Grafting (CABG) is sometimes necessary in acute Type A Aortic Dissection (AAAD) repair. The aim of this study is to analyze the incidence, indications and influence in-hospital outcomes of AAAD repair requiring concomitant CABG in a high-volume single-center experience. Retrospective study of all consecutive AAAD patients. Those who underwent concomitant CABG were identified. Preoperative, intraoperative, postoperative and follow-up data were collected and analyzed. Between January 1, 2010 and December 31, 2016, 382 patients underwent emergency surgery for AAAD. Forty-one (10.7%) underwent concomitant CABG. In this group, mean age was 64 ± 14 years, 32 were male (78%). Indication for CABG was coronary dissection in 28 patients (68.3%), post-cardiopulmonary bypass (CPB) right heart failure in 7 (17.1%), post CPB left heart failure in (7.3%) and native coronary pathology in 3 (7.3%). In 33 (80.5%) one graft was needed, in 7 (17%) two were performed and in 1 patient (2.4%) 3 were necessary. The right coronary artery (RCA) was the only revascularized vessel in 26 cases (63.4%), the left coronary artery (LCA) alone in 11 (26.8%), and both coronary systems in 4 (9.8%). In-hospital mortality was 51.2% (N = 21); eight (19.5%) patients had postoperative myocardial infarction (MI) and 11 (26.8%) had a major neurological event. Multivariable logistic regression identified concomitant CABG as a predictor of in-hospital mortality (Odds Ratio (OR) = 3.8115, 95% CI= 0.514-2.138, p = 0.001). In our study, concomitant CABG was performed in 10.7% of AAAD repair surgery and it was associated with high in-hospital mortality.
Keywords: Concomitant CABG; Predictors of mortality; Type A acute aortic dissectio
Aortic wrapping is life-saving in high-risk acute aortic dissection and intramural haematoma
Aortic wrapping is a controversial repair in patients presenting with acute type A aortic dissection or intramural haematoma, but this method may be a potential alternative to medical treatment or conventional repair in patients aged >80 years and in those presenting with prohibitive co-morbidities such as stroke, circulatory collapse, full oral anticoagulation with the last generation drugs. We report on 5 high-risk and/or patients over 80 years who received external aortic wrapping with or without cardiopulmonary bypass during the last 18 months. All survived the procedure and could be extubated early postoperatively. No patient remained on the intensive care longer than 2 days and all were discharged without additional complications. Postoperative radiological control was acceptable and no patient had any new aortic event up to 18 months postoperatively
Vascular graft infections
Vascular graft infections are rare complications after surgical and endovascular treatment of aortic diseases. This condition is characterized by complexity in diagnosis and medico-surgical management. Moreover, even if properly treated, morbidity and mortality rates are high. Although several advances have been made over the years and guidelines of treatment have been published, there is still debate on the optimal care for this disease. With local microbiological patterns and multiresistant strains conditioning antimicrobial treatment as well as several surgical debridement techniques in the armamentarium, it is difficult to offer recommendations that can be generalized for every single case. In this review, we aim at describing thoracic and abdominal vascular graft infections and providing current information on diagnosis, medical treatment, and surgical management
Indications and Outcomes of Second Aortic Procedures After Acute Type A Dissection Repair
OBJECTIVES
Aortic arch or aortic root replacement is not performed in all cases of acute type A aortic dissection (ATAD), and a second aortic procedure will become necessary over time for some patients. Indications and outcomes, of second aortic procedures have not been studied extensively.
METHODS
Characteristics and in-hospital outcomes of all patients undergoing surgical repair for type A acute aortic dissection were analysed and patients needing second aortic procedure during follow-up were identified. The latter group was divided in 2 subgroups: on-pump includes patients operated on using cardiopulmonary bypass and off-pump without cardiopulmonary bypass.
RESULTS
A total of 638 patients underwent surgery for ATAD; 8% required a second aortic procedure. The most frequent indication for the second aortic procedure was dehiscence of suture lines (44%), followed by arch dilatation (24%). In-hospital mortality was 12%. Isolated ascending aorta replacement at the first surgery was associated with higher incidence of second aortic procedure (P = 0.006). Most patients in the on-pump group underwent a proximal reoperation (75%), with a mortality rate of 14.2%. In-hospital mortality of patients in the off-pump group was 7.7%. Long-term survival analysis showed no difference between groups (P = 0,526), Off-pump patients have greater likelihood of a second intervention during follow-up (P = 0.004).
CONCLUSIONS
Extended aortic root surgery and customized aortic arch repair in ATAD could be reasonable to reduce the incidence and mortality of high-risk second aortic procedures
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