Overt ischemic colitis after endovascular repair of aortoiliac aneurysms

AbstractObjectiveControversy exists as to the cause of ischemic colitis complicating endovascular aneurysm repair. Occlusion of the hypogastric arteries (HAs) during endovascular repair of aortoiliac aneurysms (AIAs) results in a significant incidence of buttock claudication, and has been suggested as a causative factor in the development of postprocedural colonic ischemia, in addition to factors such as systemic hypotension, embolization of atheromatous debris, and interruption of inferior mesenteric artery inflow. To analyze the relationship between perioperative HA occlusion and postoperative ischemic colitis, we reviewed our experience over 2 years with Food and Drug Administration–approved endovascular graft devices for treatment of AIAs.MethodsElective repair of AIAs with bifurcated endovascular grafts was performed in 233 patients over a 2-year period. These included 184 AneuRx grafts, 17 Ancure grafts, and 32 Excluder grafts. During the experience, 44 patients (18.9%) underwent unilateral perioperative HA occlusion (28 right, 16 left) during the course of endovascular AIA repair, and 1 patient (0.4%) underwent bilateral HA occlusion.ResultsIn 4 patients (1.7%) signs and symptoms of ischemic colitis developed 2.0 ± 1.4 days postoperatively. In all patients the diagnosis was confirmed at sigmoidoscopy, and initial treatment included bowel rest, hydration, and intravenous antibiotic agents. Three patients with bilateral patent HAs required colonic resection 14.7 ± 9.7 days after the initial diagnosis, and 2 of these 3 patients died in the postoperative period. Pathologic findings confirmed the presence of atheroemboli in the colonic vasculature in all 3 patients who underwent colonic resection. The fourth patient had undergone multiple manipulations of the left HA in an unsuccessful attempt to preserve patency of this vessel during AIA repair. This patient recovered completely with nonoperative management. Perioperative unilateral HA occlusion was not associated with a significantly higher incidence of postoperative ischemic colitis.ConclusionPerioperative HA occlusion during aortoiliac open or endovascular surgery may contribute to development of the rare but potentially lethal complication of ischemic colitis. However, our extensive experience suggests that embolization of atheromatous debris to the HA tissue beds during endovascular manipulations, rather than proximal HA occlusion, is the primary cause of clinically significant ischemic colitis after endovascular aneurysm repair

Observation of a new Xi(b) baryon

The first observation of a new b baryon via its strong decay into Xi(b)^- pi^+ (plus charge conjugates) is reported. The measurement uses a data sample of pp collisions at sqrt(s) = 7 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 5.3 inverse femtobarns. The known Xi(b)^- baryon is reconstructed via the decay chain Xi(b)^- to J/psi Xi^- to mu^+ mu^- Lambda^0 pi^-, with Lambda^0 to p pi^-. A peak is observed in the distribution of the difference between the mass of the Xi(b)^- pi^+ system and the sum of the masses of the Xi(b)^- and pi^+, with a significance exceeding five standard deviations. The mass difference of the peak is 14.84 +/- 0.74 (stat.) +/- 0.28 (syst.) MeV. The new state most likely corresponds to the J^P=3/2^+ companion of the Xi(b).Comment: Submitted to Physical Review Letter

Measurement of the charge ratio of atmospheric muons with the CMS detector

This is the pre-print version of this Article. The official published version can be accessed from the link below - Copyright @ 2010 ElsevierWe present a measurement of the ratio of positive to negative muon fluxes from cosmic ray interactions in the atmosphere, using data collected by the CMS detector both at ground level and in the underground experimental cavern at the CERN LHC. Muons were detected in the momentum range from 5 GeV/c to 1 TeV/c. The surface flux ratio is measured to be 1.2766 \pm 0.0032(stat.) \pm 0.0032 (syst.), independent of the muon momentum, below 100 GeV/c. This is the most precise measurement to date. At higher momenta the data are consistent with an increase of the charge ratio, in agreement with cosmic ray shower models and compatible with previous measurements by deep-underground experiments

Measurements of inclusive W and Z cross sections in pp collisions at root s=7 TeV

This is the pre-print version of the Published Article, which can be accessed from the link below - Copyright @ 2011 Springer VerlagMeasurements of inclusive W and Z boson production cross sections in pp collisions at sqrt(s)=7 TeV are presented, based on 2.9 inverse picobarns of data recorded by the CMS detector at the LHC. The measurements, performed in the electron and muon decay channels, are combined to give sigma(pp to WX) times B(W to muon or electron + neutrino) = 9.95 \pm 0.07(stat.) \pm 0.28(syst.) \pm 1.09(lumi.) nb and sigma(pp to ZX) times B(Z to oppositely charged muon or electron pairs) = 0.931 \pm 0.026(stat.) \pm 0.023(syst.) \pm 0.102(lumi.) nb. Theoretical predictions, calculated at the next-to-next-to-leading order in QCD using recent parton distribution functions, are in agreement with the measured cross sections. Ratios of cross sections, which incur an experimental systematic uncertainty of less than 4%, are also reported

Measurement of dijet angular distributions and search for quark compositeness in pp collisions at √s=7TeV

Dijet angular distributions are measured over a wide range of dijet invariant masses in pp collisions at root s = 7 TeV, at the CERN LHC. The event sample, recorded with the CMS detector, corresponds to an integrated luminosity of 36 pb(-1). The data are found to be in good agreement with the predictions of perturbative QCD, and yield no evidence of quark compositeness. With a modified frequentist approach, a lower limit on the contact interaction scale for left-handed quarks of Lambda(+) = 5.6 TeV (Lambda(-) = 6.7 TeV) for destructive (constructive) interference is obtained at the 95% confidence level

Realising Team-Working in the Field: An Agent-based Approach

Multi-agent systems technology is applied to enable co-operation between mobile workers in the field, minimising user intervention and increasing reachability. A component-based approach is taken to simplify the management of deployed co-operation services. A Personal Assistant running on a mobile device is introduced to show how an intelligent and autonomous agent can increase the utility of users during workforce co-operation processes. Finally, a real world trial of the technology by network installation and maintenance engineers in the UK is described. Some technical issues revealed during the trial are discussed, as is the impact of the technology on the business process