To wet or not to wet: that is the question

Wetting transitions have been predicted and observed to occur for various combinations of fluids and surfaces. This paper describes the origin of such transitions, for liquid films on solid surfaces, in terms of the gas-surface interaction potentials V(r), which depend on the specific adsorption system. The transitions of light inert gases and H2 molecules on alkali metal surfaces have been explored extensively and are relatively well understood in terms of the least attractive adsorption interactions in nature. Much less thoroughly investigated are wetting transitions of Hg, water, heavy inert gases and other molecular films. The basic idea is that nonwetting occurs, for energetic reasons, if the adsorption potential's well-depth D is smaller than, or comparable to, the well-depth of the adsorbate-adsorbate mutual interaction. At the wetting temperature, Tw, the transition to wetting occurs, for entropic reasons, when the liquid's surface tension is sufficiently small that the free energy cost in forming a thick film is sufficiently compensated by the fluid- surface interaction energy. Guidelines useful for exploring wetting transitions of other systems are analyzed, in terms of generic criteria involving the "simple model", which yields results in terms of gas-surface interaction parameters and thermodynamic properties of the bulk adsorbate.Comment: Article accepted for publication in J. Low Temp. Phy

Measurement of event-shape observables in Z→ℓ+ℓ− events in pp collisions at √ s=7 TeV with the ATLAS detector at the LHC

Event-shape observables measured using charged particles in inclusive $Z$-boson events are presented, using the electron and muon decay modes of the $Z$ bosons. The measurements are based on an integrated luminosity of $1.1 {\rm fb}^{-1}$ of proton--proton collisions recorded by the ATLAS detector at the LHC at a centre-of-mass energy $\sqrt{s}=7$ TeV. Charged-particle distributions, excluding the lepton--antilepton pair from the $Z$-boson decay, are measured in different ranges of transverse momentum of the $Z$ boson. Distributions include multiplicity, scalar sum of transverse momenta, beam thrust, transverse thrust, spherocity, and $\mathcal{F}$-parameter, which are in particular sensitive to properties of the underlying event at small values of the $Z$-boson transverse momentum. The Sherpa event generator shows larger deviations from the measured observables than Pythia8 and Herwig7. Typically, all three Monte Carlo generators provide predictions that are in better agreement with the data at high $Z$-boson transverse momenta than at low $Z$-boson transverse momenta and for the observables that are less sensitive to the number of charged particles in the event.Comment: 36 pages plus author list + cover page (54 pages total), 14 figures, 4 tables, submitted to EPJC, All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2014-0

Chemoprevention of gastrointestinal cancer

Lags behind prevention of other disease

Trefoil Factor Expression in a Human Model of the Early Stages of Barrett's Esophagus

Background: Trefoil proteins are believed to have an important role in mucosal protection and repair in the gastrointestinal tract. They are well recognized in Barrett's esophagus and considered a potential biomarker for the condition. Metaplasia occurring in the esophageal remnant after esophagectomy is a human model for the early stages of development of Barrett's esophagus. Aims: To assess expression of trefoil proteins in post-esophagectomy columnar epithelium and to use trefoils as a molecular tool to understand regenerative mucosa in the esophagus. Methods: Patients with columnar metaplasia in the esophageal remnant were recruited from a large esophago-gastric cancer center. Trefoil factor expression was determined using immunohistochemical techniques. Results: Samples were obtained from 37 patients. TFF1 and TFF2 were expressed by all samples in a similar pattern to that described in studies of sporadic Barrett's esophagus. TFF3 was less widely expressed and was significantly associated with time elapsed between surgery and endoscopy. Median time from surgery to endoscopy was 8.1 years for patients with TFF3 expression versus 3.4 years for those without (p = 0.004). Conclusions: Widespread expression of trefoils in this environment suggests that these proteins have an important role in development of Barrett's metaplasia. TFF3 expression may be absent in the early stages of metaplasia and may represent more established columnar epithelium. Biopsy samples from post-esophagectomy patients provide a valuable resource to study the early stages of Barrett's esophagus. © 2014, Springer Science+Business Media New York

Columnar metaplasia in the oesophageal remnant following oesophagectomy - a common occurrence and a valuable insight into the development of Barrett's oesophagus

Abstract - Cancer/Surgical Oncology (GI) 0775Abstract The International Surgical Congress of the Association of Surgeons of Great Britain and Ireland takes place this year in Liverpool, UK (9–11 May 2012).L. J. Dunn, J. Shenfine, A. D. Burt, J. A. Jankowski, S. M. Griffi

Late quaternary climate change in Australia's arid interior: Evidence from Kati Thanda – Lake Eyre

Williams Point is an iconic late Quaternary sedimentary sequence exposed at the southern margin of Madigan Gulf at Kati Thanda e Lake Eyre (KT-LE), Australia's largest lake. The ~15 m high cliff outcrop includes 6 m of aeolian sediments, capping a ~0.5 m beach/shoreline facies containing abundant Coxiella (aquatic gastropod) unconformably overlying 5e6 m of fluvio-lacustrine facies. The base of the outcrop and the playa floor comprises shallow and deeper water laminated lacustrine sediments. We re-examine the stratigraphic sequence using detailed excavations, micromorphological analysis and geochemical characterisation (X-ray fluorescence, X-ray diffraction, palaeoecology, stable isotope analysis of gypsum hydration water and biogenic carbonates, rare earth element analysis) and present a revised chronology using single-grain optically stimulated luminescence (OSL) within a Bayesian framework. Our new chronostratigraphic data generally supports previous interpretations for Williams Point, but crucially refines the timing of several of the key sedimentological units. The deeper-water lacustrine facies on the lake floor, unconformably overlying the Miocene Etadunna Formation, were deposited 206 ± 13 ka (232 e169 ka, 95% credible interval; C.I.). A palaeoplaya, or oxidised shallow lake deposits, formed at 153 ± 11 ka (175e131 ka, 95% C.I.) and the uppermost shallow water lacustrine facies at the base of the cliff was deposited at 131 ± 9 ka (150e113 ka, 95% C.I.). An unconformity separates these sediments from the overlying fluvio-lacustrine phase, securely constrained (with eight OSL samples) to 86 ± 4 ka (95e78 ka, 95% C.I.). The isotopic composition of the palaeo-lake water (d18O and dD), reconstructed from the hydration water of syndepositional gypsum formed in-situ in these fluvio-lacustrine sediments, indicates wetter conditions at 95e78 ka than at ca. 232e131 ka. Based on the provenance analysis these fluviolacustrine and lacustrine sediments were sourced from the northern catchments within the Lake Eyre basin but with an additional contribution from the northern Flinders Ranges. An erosional unconformity separates this sedimentary unit from the overlying Coxiella beach facies, which itself dates to 71 ± 4 ka (79e63 ka; 95% C.I.). This beach facies is interpreted to represent a regressional shoreline or near-shore deposit formed during Marine Isotope Stage [MIS] 4. This is the most reliable palaeolake level indicator in the sequence and indicates a maximum water depth of 12 m. The overlying Williams Point aeolian unit (WPAU) dates to 49 ± 4 ka (56e41 ka, 95% C.I.), slightly younger than previous estimates. The modelled age for WPAU overlaps with (and is within uncertainty of) the last KT-LE megalake phase, which reached þ5 m AHD at 48 ± 2 ka. However, considering its elevation (3 to þ3 m AHD), the age of this gypsiferous aeolian unit demands that it accreted as KT-LE was entering a playa phase with lengthy periods of exposed lake floor. In turn, this means that the putative Genyornis newtoni (a megafaunal flightless bird) which laid its eggs in the gypsiferous dunes, went extinct during a time of hydrological transformation. These results bring fresh perspectives to a site that has held a heavy sway over previous views of the Quaternary history of Australia's arid zone.Tim J. Cohen, Lee J. Arnold, Fernando Gazquez, Jan-Hendrik May, Sam K. Marx, Nathan R. Jankowski, Allan R. Chivas, Adriana Garcia, Haidee Cadd, Adrian G. Parker, John D. Jansen, Xiao Fu, Nicolas Waldmann, Gerald C. Nanson, Brian G. Jones, Patricia Gad