Quantumgroups in the Higgs Phase

In the Higgs phase we may be left with a residual finite symmetry group H of the condensate. The topological interactions between the magnetic- and electric excitations in these so-called discrete H gauge theories are completely described by the Hopf algebra or quantumgroup D(H). In 2+1 dimensional space time we may add a Chern-Simons term to such a model. This deforms the underlying Hopf algebra D(H) into a quasi-Hopf algebra by means of a 3-cocycle H. Consequently, the finite number of physically inequivalent discrete H gauge theories obtained in this way are labelled by the elements of the cohomology group H^3(H,U(1)). We briefly review the above results in these notes. Special attention is given to the Coulomb screening mechanism operational in the Higgs phase. This mechanism screens the Coulomb interactions, but not the Aharonov-Bohm interactions. (Invited talk given by Mark de Wild Propitius at `The III International Conference on Mathematical Physics, String Theory and Quantum Gravity', Alushta, Ukraine, June 13-24, 1993. To be published in Theor. Math. Phys.)Comment: 19 pages in Latex, ITFA-93-3

Vortices on Higher Genus Surfaces

We consider the topological interactions of vortices on general surfaces. If the genus of the surface is greater than zero, the handles can carry magnetic flux. The classical state of the vortices and the handles can be described by a mapping from the fundamental group to the unbroken gauge group. The allowed configurations must satisfy a relation induced by the fundamental group. Upon quantization, the handles can carry ``Cheshire charge.'' The motion of the vortices can be described by the braid group of the surface. How the motion of the vortices affects the state is analyzed in detail.Comment: 28 pages with 10 figures; uses phyzzx and psfig; Caltech preprint CALT-68-187

Outcomes of Distal Pancreatectomy for Pancreatic Ductal Adenocarcinoma in the Netherlands: A Nationwide Retrospective Analysis

Background: Large multicenter series on outcomes and predictors of survival after distal pancreatectomy (DP) for pancreatic ductal adenocarcinoma (PDAC) are scarce. Methods: Adults who underwent DP for PDAC in 17 Dutch pancreatic centers between January 2005 and September 2013 were analyzed retrospectively. The primary outcome was survival, and predictors of survival were identified using Cox regression analysis. Results: In total, 761 consecutive patients after DP were assessed, of whom 620 patients were excluded because of non-PDAC histopathology (n = 616) or a lack of data (n = 4), leaving a total of 141 patients included in the stud

Colonic stenting versus emergency surgery for acute left-sided malignant colonic obstruction: a multicentre randomised trial

Cellular mechanisms in basic and clinical gastroenterology and hepatolog

Minimally invasive versus open pancreatoduodenectomy (LEOPARD-2): Study protocol for a randomized controlled trial

Background: Data from observational studies suggest that minimally invasive pancreatoduodenectomy (MIPD) is superior to open pancreatoduodenectomy regarding intraoperative blood loss, postoperative morbidity, and length of hospital stay, without increasing total costs. However, several case-matched studies failed to demonstrate superiority of MIPD, and large registry studies from the USA even suggested increased mortality for MIPDs performed in low-volume (< 10 MIPDs annually) centers. Randomized controlled multicenter trials are lacking but clearly required. We hypothesize that time to functional recovery is shorter after MIPD compared with open pancreatoduodenectomy, even in an enhanced recovery setting. Methods/design: LEOPARD-2 is a randomized controlled, parallel-group, patient-blinded, multicenter, phase 2/3, superiority trial in centers that completed the Dutch Pancreatic Cancer Group LAELAPS-2 training program for laparoscopic pancreatoduodenectomy or LAELAPS-3 training program for robot-assisted pancreatoduodenectomy and have performed ≥ 20 MIPDs. A total of 136 patients with symptomatic benign, premalignant, or malignant disease will be randomly assigned to undergo minimally invasive or open pancreatoduodenectomy in an enhan

Minimally invasive versus open distal pancreatectomy: an individual patient data meta-analysis of two randomized controlled trials

Background: Minimally invasive distal pancreatectomy (MIDP) has been suggested to reduce postoperative outcomes as compared to open distal pancreatectomy (ODP). Recently, the first randomized controlled trials (RCTs) comparing MIDP to ODP were published. This individual patient data meta-analysis compared outcomes after MIDP versus ODP combining data from both RCTs. Methods: A systematic literature search was performed to identify RCTs on MIDP vs. ODP, and individual patient data were harmonized. Primary endpoint was the rate of major (Clavien-Dindo ≥ III) complications. Sensitivity analyses were performed in high-risk subgroups. Results: A total of 166 patients from the LEOPARD and LAPOP RCTs were included. The rate of major complications was 21% after MIDP vs. 35% after ODP (adjusted odds ratio 0.54; p = 0.148). MIDP significantly reduced length of hospital stay (6 vs. 8 days, p = 0.036), and delayed gastric emptying (4% vs. 16%, p = 0.049), as compared to ODP. A trend towards higher rates of postoperative pancreatic fistula was observed after MIDP (36% vs. 28%, p = 0.067). Outcomes were comparable in high-risk subgroups. Conclusion: This individual patient data meta-analysis showed that MIDP, when performed by trained surgeons, may be regarded as the preferred approach for distal pancreatectomy. Outcomes are improved after MIDP as compared to ODP, without obvious downsides in high-risk subgroups