88 research outputs found
Biliary tract cancer metastases in port site after laparoscopic cholecystectomy - a case report
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Phase Stability of Chromium(III) Oxide Hydroxide in Alkaline Sodium Phosphate Solutions
Grimaldiite ({alpha}-CrOOH) is shown to transform to a sodium-chromium(III)-hydroxyphosphate compound (SCHP) in alkaline sodium phosphate solutions at elevated temperatures via CrOOH(s) + 4Na{sup +} + 2HPO{sub 4}{sup 2-} = Na{sub 4}Cr(OH)(PO{sub 4}){sub 2}(s) + H{sub 2}O. X-ray diffraction analyses indicate that SCHP possesses an orthorhombic lattice having the same space group symmetry (Ibam, No.72) as sodium ferric hydroxyphosphate. A structurally-consistent designation for SCHP is Na{sub 3}Cr(PO{sub 4}){sub 2} {center_dot} NaOH; the molar volume of SCHP is estimated to be 1552 cm{sup 3}. The thermodynamic equilibrium for the above reaction was defined in the system Na{sub 2}O-P{sub 2}O{sub 5}-Cr{sub 2}O{sub 3}-H{sub 2}O for Na/P molar ratios between 2.0 and 2.4. On the basis of observed reaction threshold values for sodium phosphate concentration and temperature, the standard molar entropy (S{sup o}), heat capacity (C{sub p}{sup o}) and free energy of formation ({Delta}G{sub f}{sup o}) for SCHP were calculated to be 690 J/(mol-K), 622 J/(mol-K) and -3509.97 kJ/mol, respectively
Kinematic studies of transport across an island wake, with application to the Canary islands
Transport from nutrient-rich coastal upwellings is a key factor influencing
biological activity in surrounding waters and even in the open ocean. The rich
upwelling in the North-Western African coast is known to interact strongly with
the wake of the Canary islands, giving rise to filaments and other mesoscale
structures of increased productivity. Motivated by this scenario, we introduce
a simplified two-dimensional kinematic flow describing the wake of an island in
a stream, and study the conditions under which there is a net transport of
substances across the wake. For small vorticity values in the wake, it acts as
a barrier, but there is a transition when increasing vorticity so that for
values appropriate to the Canary area, it entrains fluid and enhances
cross-wake transport.Comment: 28 pages, 13 figure
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Solubility of Litharge (a-PbO) in Alkaline Media at Elevated Temperatures
An inert, flowing autoclave facility is used to investigate the solubility behavior of {alpha}-PbO (litharge, tetragonal) in aqueous solutions of morpholine, ammonia and sodium hydroxide between 38 and 260 C. Lead solubilities increased from about 0.4 mmol kg{sup -1} at 38 C to about 4.5 mmol kg{sup -1} at 260 C and were relatively insensitive to the concentration and identity of the pH-reagent. The measured lead solubilities were interpreted using a Pb(II) ion hydroxocomplexing model and thermodynamic functions for these equilibria were obtained from a least-squares analysis of the data. A consistent set of thermodynamic properties for the species Pb(OH){sup +}, Pb(OH){sub 2}(aq) and Pb(OH){sub 3}{sup -} is provided to permit accurate lead oxide solubility calculations over broad ranges of temperature and alkalinity
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Oxidative Dissolution of Nickel Metal in Hydrogenated Hydrothermal Solutions
A platinum-lined, flowing autoclave facility is used to investigate the solubility behavior of metallic nickel in hydrogenated ammonia and sodium hydroxide solutions between 175 and 315 C. The solubility measurements were interpreted by means of an oxidative dissolution reaction followed by a sequence of Ni(II) ion hydrolysis reactions: Ni(s) + 2H+(aq) = Ni2+(aq) + H2(g) and Ni{sup 2+}(aq) + nH{sub 2}O = Ni(OH){sub n}{sup 2-n}(aq) + nH{sup +}(aq) where n = 1 and 2. Gibbs energies associated with these reaction equilibria were determined from a least-squares analysis of the data. The extracted thermochemical properties ({Delta}fG{sup 0}, {Delta}fH{sup 0} and S{sup 0}) for Ni2{sup +}(aq), Ni(OH){sup +}(aq) and Ni(OH){sub 2}(aq) were found to be consistent with those determined in a previous solubility study of NiO/Ni(OH){sub 2} conducted in our laboratory. The thermodynamic basis of the Ni/NiO phase boundary in aqueous solutions is examined to show that Ni(s) is stable relative to NiO(s) in solutions saturated at 25 C with 1 atm H{sub 2} for temperatures below 309 C
Miejscowe wycięcie nowotworów odbytnicy (LE) – alternatywa dla rozległych operacji brzusznych (LAR, APR)
Przerzuty raka dróg żółciowych do powłok brzusznych po cholecystectomii laparoskopowej - opis przypadku
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Solubility and Surface Adsorption Characteristics of Metal Oxides to High Temperature
The interaction of high temperature aqueous solutions with mineral surfaces plays a key role in many aspects of fossil, geothermal and nuclear energy production. This is an area of study in which the subsurface geochemical processes that determine brine composition, porosity and permeability changes, reservoir integrity, and fluid flow rates overlap with the industrial processes associated with corrosion of metal parts and deposition of solids in pipes and on heat exchanger surfaces. The sorption of ions on mineral surfaces is also of great interest in both the subsurface and ''above ground'' regimes of power production, playing a key role in subsurface migration of contaminants (nuclear waste disposal, geothermal brine re-injection, etc.) and in plant operations (corrosion mitigation, migration of radioactive metals from reactor core to heat exchanger, etc.). In this paper, results of the solubility and surface chemistry of metal oxides relevant to both regimes are summarized
Delayed HIV detection among infants exposed to postnatal antiretroviral prophylaxis during breastfeeding
The objective of this study is to determine whether detection of HIV infection was delayed in infants exposed to antiretroviral prophylaxis to prevent HIV transmission during breastfeeding
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