Corrosion of galvanic pairs of Co-Cr alloys with high-copper silver amalgam using Mansfeld formulas

In the restoration of lost or damaged dental pieces, different alloys are frequently used, leaving the mouth exposed to electrical currents that circulate through saliva and dental fluids. In the present work, electrochemical methods are used to determine the corrosion rate of galvanic pairs of a high copper silver amalgam with Co-Cr dental alloys in artificial saliva. It is observed that when the difference in corrosion potentials of dissimilar alloys are small (less than 100 mVecs), Evans diagrams do not give good results, so the Mansfeld correction formulas must be used. Thus, it is found that the most resistant to corrosion is the pair formed between the amalgam and the bulk Co-Cr alloy (PG1,3) and that the corrosion products released in greater quantity to the electrolyte are those that contain ions of Co, Cr, Ag, Sr and Cu. Keywords: Corrosion, dental alloy, polarization curve, artificial saliva, galvanic pair

Corrosion of galvanic pairs of dental alloys copper base with silver amalgams in artificial saliva

Galvanic corrosion is a metal dissolution process that occurs when two metals of different electrochemicalpotential are immersed in an electrolyte causing electrical currents between the metals through the conductingmedium. To restore lost or damaged teeth, different alloys are used, leaving the mouth exposed to electricalcurrents that circulate through saliva and dental fluids. In the present work, the potentials and densitiesof corrosion currents of galvanic pairs of silver amalgams and copper base dental alloys were determinedsimultaneously using potenciodynamic methods, finding that the most resistant to corrosion are the pairsformed by silver amalgams of high copper and Cu - Zn alloys, and that the corrosion products released ingreater quantity in the electrolytic medium are formed by Hg, Cu, Zn and Ni ions.Keywords. Corrosion, dental alloy, polarization curve, artificial saliva, galvanic pair

Corrosion of galvanic couplings of Ni-Cr and Co-Cr alloys with Ti-6Al-4V in artificial saliva using electrochemical methods

In this work, the open-circuit corrosion potentials of the alloys studied in aerated artificial saliva were determined; in the same solution, the potentiodynamic polarization curves of said alloys have been drawn. The corrosion potentials and current intensities of the galvanic coupling of the Ti-6Al-4V alloy with the Co-Cr and Ni-Cr alloys were determined using the Evans method, finding that the galvanic couples more resistant to corrosion in the electrolytic medium considered are those formed between the Ti alloy and the Co-Cr alloys; the least resistant are those formed between Ti alloy and Ni-Cr alloys. The corroded surfaces of the seven alloys considered in this work were also studied, and by EDAX the corrosion products due to the ions detached in the electrolytic medium were analyzed. Keywords: Galvanic couplings, dental alloys, Co-Cr, Ni-Cr, corrosion

Cumplimiento farmacoterapéutico en pacientes con enfermedad pulmonar obstructiva crónica, atendidos en el centro de salud Perla María Norori, en el periodo de enero-diciembre 2014

Tesis (Lic. Químico Farmacéutico)-Universidad Nacional Autónoma de Nicaragua, LeónUNAN-Leó

A survey of the year 2006 literature on applications of isothermal titration calorimetry

Isothermal titration calorimetry (ITC) is a fast and robust method to determine the energetics of association reactions in solution. The changes in enthalpy, entropy and heat capacity that accompany binding provide unique insights into the balance of forces driving association of molecular entities. ITC is used nowadays on a day-to-day basis in hundreds of laboratories. The method aids projects both in basic and practice-oriented research ranging from medicine and biochemistry to physical chemistry and material sciences. Not surprisingly, the range of studies utilizing ITC data is steadily expanding. In this review, we discuss selected results and ideas that have accumulated in the course of the year 2006, the focus being on biologically relevant systems. Theoretical developments, novel applications and studies that provide a deeper level of understanding of the energetic principles of biological function are primarily considered. Following the appearance of a new generation of titration calorimeters, recent papers provide instructive examples of the synergy between energetic and structural approaches in biomedical and biotechnological research

ATLAS

% ATLAS \\ \\ ATLAS is a general-purpose experiment for recording proton-proton collisions at LHC. The ATLAS collaboration consists of 144 participating institutions (June 1998) with more than 1750~physicists and engineers (700 from non-Member States). The detector design has been optimized to cover the largest possible range of LHC physics: searches for Higgs bosons and alternative schemes for the spontaneous symmetry-breaking mechanism; searches for supersymmetric particles, new gauge bosons, leptoquarks, and quark and lepton compositeness indicating extensions to the Standard Model and new physics beyond it; studies of the origin of CP violation via high-precision measurements of CP-violating B-decays; high-precision measurements of the third quark family such as the top-quark mass and decay properties, rare decays of B-hadrons, spectroscopy of rare B-hadrons, and $B ^0 _{s}$-mixing. \\ \\The ATLAS dectector, shown in the Figure includes an inner tracking detector inside a 2~T~solenoid providing an axial field, electromagnetic and hadronic calorimeters outside the solenoid and in the forward regions, and barrel and end-cap air-core-toroid muon spectrometers. The precision measurements for photons, electrons, muons and hadrons, and identification of photons, electrons, muons, $\tau$-leptons and b-quark jets are performed over $| \eta |$ < 2.5. The complete hadronic energy measurement extends over $| \eta |$ < 4.7. \\ \\The inner tracking detector consists of straw drift tubes interleaved with transition radiators for robust pattern recognition and electron identification, and several layers of semiconductor strip and pixel detectors providing high-precision space points. \\ \\The e.m. calorimeter is a lead-Liquid Argon sampling calorimeter with an integrated preshower detector and a presampler layer immediately behind the cryostat wall for energy recovery. The end-cap hadronic calorimeters also use Liquid Argon technology, with copper absorber plates. The end-cap cryostats house the e.m., hadronic and forward calorimeters (tungsten-Liquid Argon sampling). The barrel hadronic calorimeter is an iron-scintillating tile sampling calorimeter with longitudinal tile geometry. \\ \\Air-core toroids are used for the muon spectrometer. Eight superconducting coils with warm voussoirs are used in the barrel region complemented with superconducting end-cap toroids in the forward regions. The toroids will be instrumented with Monitored Drift Tubes (Cathode Strip Chambers at large rapidity where there are high radiation levels). The muon trigger and second coordinate measurement for muon tracks are provide