Reversed anisotropies and thermal contraction of FCC (110) surfaces

The observed anisotropies of surface vibrations for unreconstructed FCC metal (110) surfaces are often reversed from the "common sense" expectation. The source of these reversals is investigated by performing ab initio density functional theory calculations to obtain the surface force constant tensors for Ag(110), Cu(110) and Al(110). The most striking result is a large enhancement in the coupling between the first and third layers of the relaxed surface, which strongly reduces the amplitude of out-of-plane vibrations of atoms in the first layer. This also provides a simple explanation for the thermal contraction of interlayer distances. Both the anisotropies and the thermal contraction arise primarily as a result of the bond topology, with all three (110) surfaces showing similar behavior.Comment: 13 pages, in revtex format, plus 1 postscript figur

β-Catenin Loss in Hepatocytes Promotes Hepatocellular Cancer after Diethylnitrosamine and Phenobarbital Administration to Mice

Hepatocellular Carcinoma (HCC) is the fifth most common cancer worldwide. β-Catenin, the central orchestrator of the canonical Wnt pathway and a known oncogene is paramount in HCC pathogenesis. Administration of phenobarbital (PB) containing water (0.05% w/v) as tumor promoter following initial injected intraperitoneal (IP) diethylnitrosamine (DEN) injection (5 µg/gm body weight) as a tumor inducer is commonly used model to study HCC in mice. Herein, nine fifteen-day male β-catenin knockout mice (KO) and fifteen wild-type littermate controls (WT) underwent DEN/PB treatment and were examined for hepatic tumorigenesis at eight months. Paradoxically, a significantly higher tumor burden was observed in KO (p<0.05). Tumors in KO were β-catenin and glutamine synthetase negative and HGF/Met, EGFR & IGFR signaling was unremarkable. A significant increase in PDGFRα and its ligand PDGF-CC leading to increased phosphotyrosine-720-PDGFRα was observed in tumor-bearing KO mice (p<0.05). Simultaneously, these livers displayed increased cell death, stellate cell activation, hepatic fibrosis and cell proliferation. Further, PDGF-CC significantly induced hepatoma cell proliferation especially following β-catenin suppression. Our studies also demonstrate that the utilized DEN/PB protocol in the WT C57BL/6 mice did not select for β-catenin gene mutations during hepatocarcinogenesis. Thus, DEN/PB enhanced HCC in mice lacking β-catenin in the liver may be due to their ineptness at regulating cell survival, leading to enhanced fibrosis and regeneration through PDGFRα activation. β-Catenin downregulation also made hepatoma cells more sensitive to receptor tyrosine kinases and thus may be exploited for therapeutics

Liver resection and ablation for squamous cell carcinoma liver metastases.

Funder: Region StockholmFunder: Region Stockholm (clinical postdoctoral appointment)BACKGROUND: Limited evidence exists to guide the management of patients with liver metastases from squamous cell carcinoma (SCC). The aim of this retrospective multicentre cohort study was to describe patterns of disease recurrence after liver resection/ablation for SCC liver metastases and factors associated with recurrence-free survival (RFS) and overall survival (OS). METHOD: Members of the European-African Hepato-Pancreato-Biliary Association were invited to include all consecutive patients undergoing liver resection/ablation for SCC liver metastases between 2002 and 2019. Patient, tumour and perioperative characteristics were analysed with regard to RFS and OS. RESULTS: Among the 102 patients included from 24 European centres, 56 patients had anal cancer, and 46 patients had SCC from other origin. RFS in patients with anal cancer and non-anal cancer was 16 and 9 months, respectively (P = 0.134). A positive resection margin significantly influenced RFS for both anal cancer and non-anal cancer liver metastases (hazard ratio 6.82, 95 per cent c.i. 2.40 to 19.35, for the entire cohort). Median survival duration and 5-year OS rate among patients with anal cancer and non-anal cancer were 50 months and 45 per cent and 21 months and 25 per cent, respectively. For the entire cohort, only non-radical resection was associated with worse overall survival (hazard ratio 3.21, 95 per cent c.i. 1.24 to 8.30). CONCLUSION: Liver resection/ablation of liver metastases from SCC can result in long-term survival. Survival was superior in treated patients with liver metastases from anal versus non-anal cancer. A negative resection margin is paramount for acceptable outcome

Estimation of the electron-phonon coupling parameter of Mo(110)-H and W(110)H

For the Kohn anomaly systems Mo(110)-(1x1)H and W(110)-(1x1)H we give an estimate of the electron-phonon coupling parameter. To this end we measured the energy of softened surface phonons at different temperatures by electron energy loss spectroscopy and exploited the fact that the Kohn anomaly weakens upon increasing the temperature. On the basis of the obtained coupling parameter we predict the critical temperature for the transition from the dynamically to the statically distorted lattice

Anomalous dispersion of adsorbate phonons of Mo(110)-H

The dispersion curve of the longitudinal-optical adsorbate phonon on hydrogen-saturated Mo(110) along [001] is found to exhibit an anomalous indentation. The maximum indentation is observed at a wave vector, which coincides within the experimental angular resolution with the wave vector, at which the known giant Kohn anomaly for the transverse- and longitudinal-acoustic substrate surface phonons along [001] occurs

Bau einer thermionischen Diode mit Wärmerohrkollektor

Als ein Beitrag zum Incore-Thermionik-Reaktor (ITR)-Projekt der Bundesrepublik Deutschland wurden im Institut für Technische Physik (ITP) der Kernforschungsanlage Jülich in den Jahren 1968-1972 Grundlagenforschungsarbeiten durchgeführt, die unter anderem die Verbesserung des Wirkungsgrades von thermionischen Dioden zum Ziel hatten /1,2/. Der Wirkungsgrad einer thermionischen Diode wird von der Emitter- und Kollektoraustrittsarbeit, vom Cäsiumplasma, von den Elektrodentemperaturen und von dem Elektrodenabstand bestimmt. Die einzelnen Einflüsse dieser Parameter auf die Strom-Spannungs-Kennlinie sind jedoch nur schwer interpretierbar. Als Ergänzung zu den Grundlagenarbeiten ist es daher notwendig, Strom-Spannungskennlinien an Experimentierdioden aufzunehmen, um die Frage zu klären, ob eine bestimmte Änderung eines Diodenparameters den gewünschten Effekt auf die Leistungsabgabe der Diode hat. In der Literatur ist eine Reihe verschiedenster Dioden beschrieben, z.B. /3,4,5/, die alle für bestimmte Versuchsziele konzipiert und daher für andere Versuchsserien nicht optimal einzusetzen sind. Aus dem Ziel unserer Versuche, den Einfluß der Kollektoraustrittsarbeit auf die Diodenkennlinien zu untersuchen, ergab sich die Forderung nach der Auswechselbarkeit des Kollektors, der exakten Einstellung der Kollektortemperatur und der Änderung des Elektrodenabstandes. Als im Jahre 1969 Dr. W.A. Ranken von den Los Alamos Scientific Laboratories für ein Jahr als Gastwissenschaftler zum ITP kam, wurde im ITP begonnen, nach seinen Entwürfen eine geeignete Experimentierdiode zu konstruieren und zu bauen. Damit bot sich gleichzeitig die Möglichkeit von W.A. Ranken's technologischem Wissen auf diesem Gebiet zu lernen. Die Arbeiten an der Experimentierdiode wurden, nachdem das ITR-Projekt eingestellt worden war, Anfang 1973 abgebrochen. In diesem Abschlußbericht soll über die Konstruktionsmerkmale der Diode, sowie über die Erfahrungen bei ihrem Zusammenbau und dem Test der Einzelkomponenten berichtet werden. Bei Abbruch der Arbeiten war die Testdiode prinzipiell betriebsbereit