A mean-field kinetic lattice gas model of electrochemical cells

We develop Electrochemical Mean-Field Kinetic Equations (EMFKE) to simulate electrochemical cells. We start from a microscopic lattice-gas model with charged particles, and build mean-field kinetic equations following the lines of earlier work for neutral particles. We include the Poisson equation to account for the influence of the electric field on ion migration, and oxido-reduction processes on the electrode surfaces to allow for growth and dissolution. We confirm the viability of our approach by simulating (i) the electrochemical equilibrium at flat electrodes, which displays the correct charged double-layer, (ii) the growth kinetics of one-dimensional electrochemical cells during growth and dissolution, and (iii) electrochemical dendrites in two dimensions.Comment: 14 pages twocolumn, 17 figure

Colloquium: Mechanical formalisms for tissue dynamics

The understanding of morphogenesis in living organisms has been renewed by tremendous progressin experimental techniques that provide access to cell-scale, quantitative information both on theshapes of cells within tissues and on the genes being expressed. This information suggests that ourunderstanding of the respective contributions of gene expression and mechanics, and of their crucialentanglement, will soon leap forward. Biomechanics increasingly benefits from models, which assistthe design and interpretation of experiments, point out the main ingredients and assumptions, andultimately lead to predictions. The newly accessible local information thus calls for a reflectionon how to select suitable classes of mechanical models. We review both mechanical ingredientssuggested by the current knowledge of tissue behaviour, and modelling methods that can helpgenerate a rheological diagram or a constitutive equation. We distinguish cell scale ("intra-cell")and tissue scale ("inter-cell") contributions. We recall the mathematical framework developpedfor continuum materials and explain how to transform a constitutive equation into a set of partialdifferential equations amenable to numerical resolution. We show that when plastic behaviour isrelevant, the dissipation function formalism appears appropriate to generate constitutive equations;its variational nature facilitates numerical implementation, and we discuss adaptations needed in thecase of large deformations. The present article gathers theoretical methods that can readily enhancethe significance of the data to be extracted from recent or future high throughput biomechanicalexperiments.Comment: 33 pages, 20 figures. This version (26 Sept. 2015) contains a few corrections to the published version, all in Appendix D.2 devoted to large deformation

Forward pi^0 Production and Associated Transverse Energy Flow in Deep-Inelastic Scattering at HERA

Deep-inelastic positron-proton interactions at low values of Bjorken-x down to x \approx 4.10^-5 which give rise to high transverse momentum pi^0 mesons are studied with the H1 experiment at HERA. The inclusive cross section for pi^0 mesons produced at small angles with respect to the proton remnant (the forward region) is presented as a function of the transverse momentum and energy of the pi^0 and of the four-momentum transfer Q^2 and Bjorken-x. Measurements are also presented of the transverse energy flow in events containing a forward pi^0 meson. Hadronic final state calculations based on QCD models implementing different parton evolution schemes are confronted with the data.Comment: 27 pages, 8 figures and 3 table

Search for Doubly-Charged Higgs Boson Production at HERA

A search for the single production of doubly-charged Higgs bosons H^{\pm \pm} in ep collisions is presented. The signal is searched for via the Higgs decays into a high mass pair of same charge leptons, one of them being an electron. The analysis uses up to 118 pb^{-1} of ep data collected by the H1 experiment at HERA. No evidence for doubly-charged Higgs production is observed and mass dependent upper limits are derived on the Yukawa couplings h_{el} of the Higgs boson to an electron-lepton pair. Assuming that the doubly-charged Higgs only decays into an electron and a muon via a coupling of electromagnetic strength h_{e \mu} = \sqrt{4 \pi \alpha_{em}} = 0.3, a lower limit of 141 GeV on the H^{\pm\pm} mass is obtained at the 95% confidence level. For a doubly-charged Higgs decaying only into an electron and a tau and a coupling h_{e\tau} = 0.3, masses below 112 GeV are ruled out.Comment: 15 pages, 3 figures, 1 tabl

Early experience with robotic pancreatoduodenectomy versus open pancreatoduodenectomy:nationwide propensity-score-matched analysis

Background: Although robotic pancreatoduodenectomy has shown promising outcomes in experienced high-volume centres, it is unclear whether implementation on a nationwide scale is safe and beneficial. The aim of this study was to compare the outcomes of the early experience with robotic pancreatoduodenectomy versus open pancreatoduodenectomy in the Netherlands. Methods: This was a nationwide retrospective cohort study of all consecutive patients who underwent robotic pancreatoduodenectomy or open pancreatoduodenectomy who were registered in the mandatory Dutch Pancreatic Cancer Audit (18 centres, 2014-2021), starting from the first robotic pancreatoduodenectomy procedure per centre. The main endpoints were major complications (Clavien-Dindo grade greater than or equal to III) and in-hospital/30-day mortality. Propensity-score matching (1 : 1) was used to minimize selection bias. Results: Overall, 701 patients who underwent robotic pancreatoduodenectomy and 4447 patients who underwent open pancreatoduodenectomy were included. Among the eight centres that performed robotic pancreatoduodenectomy, the median robotic pancreatoduodenectomy experience was 86 (range 48-149), with a 7.3% conversion rate. After matching (698 robotic pancreatoduodenectomy patients versus 698 open pancreatoduodenectomy control patients), no significant differences were found in major complications (40.3% versus 36.2% respectively; P = 0.186), in-hospital/30-day mortality (4.0% versus 3.1% respectively; P = 0.326), and postoperative pancreatic fistula grade B/C (24.9% versus 23.5% respectively; P = 0.578). Robotic pancreatoduodenectomy was associated with a longer operating time (359 min versus 301 min; P &lt; 0.001), less intraoperative blood loss (200 ml versus 500 ml; P &lt; 0.001), fewer wound infections (7.4% versus 12.2%; P = 0.008), and a shorter hospital stay (11 days versus 12 days; P &lt; 0.001). Centres performing greater than or equal to 20 robotic pancreatoduodenectomies annually had a lower mortality rate (2.9% versus 7.3%; P = 0.009) and a lower conversion rate (6.3% versus 11.2%; P = 0.032). Conclusion: This study indicates that robotic pancreatoduodenectomy was safely implemented nationwide, without significant differences in major morbidity and mortality compared with matched open pancreatoduodenectomy patients. Randomized trials should be carried out to verify these findings and confirm the observed benefits of robotic pancreatoduodenectomy versus open pancreatoduodenectomy.</p

Early experience with robotic pancreatoduodenectomy versus open pancreatoduodenectomy:nationwide propensity-score-matched analysis

Background: Although robotic pancreatoduodenectomy has shown promising outcomes in experienced high-volume centres, it is unclear whether implementation on a nationwide scale is safe and beneficial. The aim of this study was to compare the outcomes of the early experience with robotic pancreatoduodenectomy versus open pancreatoduodenectomy in the Netherlands. Methods: This was a nationwide retrospective cohort study of all consecutive patients who underwent robotic pancreatoduodenectomy or open pancreatoduodenectomy who were registered in the mandatory Dutch Pancreatic Cancer Audit (18 centres, 2014-2021), starting from the first robotic pancreatoduodenectomy procedure per centre. The main endpoints were major complications (Clavien-Dindo grade greater than or equal to III) and in-hospital/30-day mortality. Propensity-score matching (1 : 1) was used to minimize selection bias. Results: Overall, 701 patients who underwent robotic pancreatoduodenectomy and 4447 patients who underwent open pancreatoduodenectomy were included. Among the eight centres that performed robotic pancreatoduodenectomy, the median robotic pancreatoduodenectomy experience was 86 (range 48-149), with a 7.3% conversion rate. After matching (698 robotic pancreatoduodenectomy patients versus 698 open pancreatoduodenectomy control patients), no significant differences were found in major complications (40.3% versus 36.2% respectively; P = 0.186), in-hospital/30-day mortality (4.0% versus 3.1% respectively; P = 0.326), and postoperative pancreatic fistula grade B/C (24.9% versus 23.5% respectively; P = 0.578). Robotic pancreatoduodenectomy was associated with a longer operating time (359 min versus 301 min; P &lt; 0.001), less intraoperative blood loss (200 ml versus 500 ml; P &lt; 0.001), fewer wound infections (7.4% versus 12.2%; P = 0.008), and a shorter hospital stay (11 days versus 12 days; P &lt; 0.001). Centres performing greater than or equal to 20 robotic pancreatoduodenectomies annually had a lower mortality rate (2.9% versus 7.3%; P = 0.009) and a lower conversion rate (6.3% versus 11.2%; P = 0.032). Conclusion: This study indicates that robotic pancreatoduodenectomy was safely implemented nationwide, without significant differences in major morbidity and mortality compared with matched open pancreatoduodenectomy patients. Randomized trials should be carried out to verify these findings and confirm the observed benefits of robotic pancreatoduodenectomy versus open pancreatoduodenectomy.</p

TNOs are cool: a survey of the transneptunian region

Over one thousand objects have so far been discovered orbiting beyond Neptune. These trans-Neptunian objects (TNOs) represent the primitive remnants of the planetesimal disk from which the planets formed and are perhaps analogous to the unseen dust parent-bodies in debris disks observed around other main-sequence stars. The dynamical and physical properties of these bodies provide unique and important constraints on formation and evolution models of the Solar System. While the dynamical architecture in this region (also known as the Kuiper Belt) is becoming relatively clear, the physical properties of the objects are still largely unexplored. In particular, fundamental parameters such as size, albedo, density and thermal properties are difficult to measure. Measurements of thermal emission, which peaks at far-IR wavelengths, offer the best means available to determine the physical properties. While Spitzer has provided some results, notably revealing a large albedo diversity in this population, the increased sensitivity of Herschel and its superior wavelength coverage should permit profound advances in the field. Within our accepted project we propose to perform radiometric measurements of 139 objects, including 25 known multiple systems. When combined with measurements of the dust population beyond Neptune (e.g. from the New Horizons mission to Pluto), our results will provide a benchmark for understanding the Solar debris disk, and extra-solar ones as well

Robot-assisted versus laparoscopic pancreatoduodenectomy:a pan-European multicenter propensity-matched study

Background: The use of robot-assisted and laparoscopic pancreatoduodenectomy is increasing, yet large adjusted analyses that can be generalized internationally are lacking. This study aimed to compare outcomes after robot-assisted pancreatoduodenectomy and laparoscopic pancreatoduodenectomy in a pan-European cohort. Methods: An international multicenter retrospective study including patients after robot-assisted pancreatoduodenectomy and laparoscopic pancreatoduodenectomy from 50 centers in 12 European countries (2009–2020). Propensity score matching was performed in a 1:1 ratio. The primary outcome was major morbidity (Clavien–Dindo ≥III). Results: Among 2,082 patients undergoing minimally invasive pancreatoduodenectomy, 1,006 underwent robot-assisted pancreatoduodenectomy and 1,076 laparoscopic pancreatoduodenectomy. After matching 812 versus 812 patients, the rates of major morbidity (31.9% vs 29.6%; P = .347) and 30-day/in-hospital mortality (4.3% vs 4.6%; P = .904) did not differ significantly between robot-assisted pancreatoduodenectomy and laparoscopic pancreatoduodenectomy, respectively. Robot-assisted pancreatoduodenectomy was associated with a lower conversion rate (6.7% vs 18.0%; P &lt; .001) and higher lymph node retrieval (16 vs 14; P = .003). Laparoscopic pancreatoduodenectomy was associated with shorter operation time (446 minutes versus 400 minutes; P &lt; .001), and lower rates of postoperative pancreatic fistula grade B/C (19.0% vs 11.7%; P &lt; .001), delayed gastric emptying grade B/C (21.4% vs 7.4%; P &lt; .001), and a higher R0-resection rate (73.2% vs 84.4%; P &lt; .001). Conclusion: This European multicenter study found no differences in overall major morbidity and 30-day/in-hospital mortality after robot-assisted pancreatoduodenectomy compared with laparoscopic pancreatoduodenectomy. Further, laparoscopic pancreatoduodenectomy was associated with a lower rate of postoperative pancreatic fistula, delayed gastric emptying, wound infection, shorter length of stay, and a higher R0 resection rate than robot-assisted pancreatoduodenectomy. In contrast, robot-assisted pancreatoduodenectomy was associated with a lower conversion rate and a higher number of retrieved lymph nodes as compared with laparoscopic pancreatoduodenectomy.</p

Minimally invasive versus open distal pancreatectomy for resectable pancreatic cancer (DIPLOMA):an international randomised non-inferiority trial

Background: The oncological safety of minimally invasive surgery has been questioned for several abdominal cancers. Concerns also exist regarding the use of minimally invasive distal pancreatectomy (MIDP) in patients with resectable pancreatic cancer as randomised trials are lacking. Methods: In this international randomised non-inferiority trial, we recruited adults with resectable pancreatic cancer from 35 centres in 12 countries. Patients were randomly assigned to either MIDP (laparoscopic or robotic) or open distal pancreatectomy (ODP). Both patients and pathologists were blinded to the assigned approach. Primary endpoint was radical resection (R0, ≥1 mm free margin) in patients who had ultimately undergone resection. Analyses for the primary endpoint were by modified intention-to-treat, excluding patients with missing data on primary endpoint. The pre-defined non-inferiority margin of −7% was compared with the lower limit of the two-sided 90% confidence interval (CI) of absolute difference in the primary endpoint. This trial is registered with the ISRCTN registry (ISRCTN44897265). Findings: Between May 8, 2018 and May 7, 2021, 258 patients were randomly assigned to MIDP (131 patients) or ODP (127 patients). Modified intention-to-treat analysis included 114 patients in the MIDP group and 110 patients in the ODP group. An R0 resection occurred in 83 (73%) patients in the MIDP group and in 76 (69%) patients in the ODP group (difference 3.7%, 90% CI −6.2 to 13.6%; pnon-inferiority = 0.039). Median lymph node yield was comparable (22.0 [16.0–30.0] vs 23.0 [14.0–32.0] nodes, p = 0.86), as was the rate of intraperitoneal recurrence (41% vs 38%, p = 0.45). Median follow-up was 23.5 (interquartile range 17.0–30.0) months. Other postoperative outcomes were comparable, including median time to functional recovery (5 [95% CI 4.5–5.5] vs 5 [95% CI 4.7–5.3] days; p = 0.22) and overall survival (HR 0.99, 95% CI 0.67–1.46, p = 0.94). Serious adverse events were reported in 23 (18%) of 131 patients in the MIDP group vs 28 (22%) of 127 patients in the ODP group. Interpretation: This trial provides evidence on the non-inferiority of MIDP compared to ODP regarding radical resection rates in patients with resectable pancreatic cancer. The present findings support the applicability of minimally invasive surgery in patients with resectable left-sided pancreatic cancer. Funding: Medtronic Covidien AG, Johnson &amp; Johnson Medical Limited, Dutch Gastroenterology Society.</p