Elastase derived elastin peptides: putative autoimmune targets in giant cell arteritis

OBJECTIVE: Histological analysis of giant cell arteritis (GCA) reveals a granulomatous reaction around the internal elastic lamina. Elastolysis by multinucleated giant cells has also been reported. We investigated elastin derived peptides as putative recall antigens for peripheral blood mononuclear cells (PBMC) from patients with GCA. METHODS: PBMC were collected from 17 patients with GCA (Group 1), 17 patients with vascular diseases, connective tissue diseases, or polymyalgia rheumatica without GCA (Group 2), and 17 healthy controls (Group 3). Cultures of PBMC with different elastin derived peptides or elastase were analyzed. RESULTS: A proliferative response was obtained only with elastate derived elastin peptides in 12/13 untreated patients with GCA. Steroid treatment was believed to abolish this proliferative response in 4 patients with GCA. PBMC from only 3/34 non-GCA subjects responded to these antigens. No proliferative response was obtained for other elastin derived peptides or elastase in any subject. CONCLUSION: Degradation of native elastin by leukocyte elastase can provide elastin derived peptides that act as autoimmune targets for T cells in GCA.     

Monitoring the variations of the oxygen transfer rate in a full scale membrane bioreactor using daily mass balances

Oxygen transfer in biological wastewater treatment processes with high sludge concentration, such as membrane bioreactor (MBR), is an important issue. The variation of alpha-factor versus mixed liquor suspended solids (MLSS) concentration was investigated in a full scale MBR plant under process conditions, using mass balances. Exhaustive data from the Supervisory Control And Data Acquisition (SCADA) and from additional online sensors (COD, DO, MLSS) were used to calculate the daily oxygen consumption (OC) using a non-steady state mass balance for COD and total N on a 24-h basis. To close the oxygen balance, OC has to match the total oxygen transfer rate (OTRtot) of the system, which is provided by fine bubble (FB) diffusers in the aeration tank and coarse bubbles (CB) in separate membrane tanks. First assessing OTR(CB) then closing the balance OC = OTRtot allowed to calculate OTR(FB) and to fit an exponential relationship between OTR(FB) and MLSS. A comparison of the alpha-factor obtained by this balance method and by direct measurements with the off-gas method on the same plant is presented and discussed.     

Corrosion in SO2 of pure and preoxidized copper at high temperature

A kinetics and morphological study of the reaction of pure SO₂ with copper over the temperature range 500–950°C showed that only Cu₂S formed despite the fact that thermodynamic ally its formation is not expected. Alternatively, the formation of Cu₂O, expected from the Cu-O-S diagram did not occur during sulfidation; however, its evaporation was observed in an atmosphere of pure SO₂ at high temperature. Thus copper differs from others metals such as nickel or cobalt by its low reactivity with SO₂ compared to the oxidation reaction; therefore, it was possible to follow the beginning of sulfidation.     

Double-sided cooling for high power IGBT modules using flip chiptechnology

A new technique for the packaging of IGBT modules has been developed. The components are sandwiched between two direct bond copper (DBC) substrates with aluminum nitride. Wire bonds are replaced with flip chip solder bumps, which allows cooling of components on both sides. Microchannel heat sinks are directly integrated in the package to decrease the thermal resistance of the module. Thus, a very compact module with high thermal performance is obtained. A prototype with two insulated gate bipolar transistors (IGBTs) and four diodes associated in parallel was realized and tested. In this paper, the innovative packaging technique is described, and results of thermal tests are presented     

Microscopic Origin of the PTC Effect in Niobium-Doped Barium Titanate

The influence of bulk conductivity on the PTC effect of Nb-doped barium titanate is investigated. Both macroscopic and microscopic resistance measurements are performed as a function of temperature. The macroscopic measurement refers to the whole sample while the microscopic one, obtained by photolithography techniques, concerns only several grains. The results show that the increase of resistivity occurs in two steps: first, an abrupt variation at the Curie temperature T_c which is ascribed to the phase transition in the bulk; second, a continuous increase above T_c which is usually explained from grain boundary potential barriers only. However, our results suggest that a nonnegligible contribution of the bulk is also involved in this increase above T_c .     

Obstetric perspectives: consensus of the gynecology department of the University of Liège. Document of the 3rd cycle studies, October 96

Eleven cases of vesicouterine fistula were reported. The initial diagnosis was made when urinary incontinence was occurring. The diagnosis was best confirmed by cystoscopy and hysterography, which was positive in 9 cases. The ultrasonographic examinations allow to visualize the fistula in 5 out of 6 cases examined and to establish the diagnosis. If sonographic examination visualizes the fistula, the performing of hysterography is not necessary. The management consists of the cure of the infection of the urogenital tract and abdominal operation based on the excision of the fistula and closing of the bladder and uterus. All operated patients were cured.     

Silicon heat pipes used as thermal spreaders

An increase in power densities in electronic devices is a direct consequence of their miniaturization and performance improvements. We propose the use of flat miniature heat pipes with micro capillary grooves to spread heat flux across a heat sink. Models of the structure were developed to calculate heat transfer limitations and temperature drops. A brass/water prototype was fabricated to demonstrate the feasibility of heat spreading using this type of heat pipe. Simulation and experimental results obtained with the prototype are described. The dissipated power reached 110 W/cm/sup 2/ without heat transfer limitations. The results are then extended to the design of this type of heat pipe in silicon. Thermal performance was calculated. Simulation, experimental results and the fabrication process are presented.     

Effects of a silicon oxide layer on reactivity of silicon with copper(I) chloride

The effect of an SiO₂ layer thermally grown or partially removed by standard cleaning treatment on the reaction between powder silicon or Si(100) wafer and solid or gaseous copper(I) chloride was studied. The rate of the reaction increases with decreasing oxide layer thickness, which is attributed to the formation of defects, such as pinholes, in the oxide layer, allowing the vapour transport of CuCl to the silicon surface. X-ray diffraction patterns indicate that the proportion of reaction products Cu₃Si, Cu₅Si and copper changes with thickness of SiO₂. In order to explain the presence of Cu₅Si and copper for thick layer and cavity formation inside Cu₃Si nuclei, it has been suggested that the reaction between Cu₃Si and CuCl is promoted.     

Intermediate size pressure vessel programme (ZB 1)

One of the focal points in the discussion about the safety of nuclear power plants is the integrity of the reactor pressure vessel.In order to prove its integrity tests are in progress in an underground test facility of the main power station in Mannheim with an intermediate size vessel from the research programme “Integrity of Components”. Patches of A 533 B and modified A 508 B material were welded into the vessel ZB 1, the test temperatures are approximately 70 and 290°C. The main goal of the tests is to measure the behaviour of artificial and natural flaws during static hydrotests and simulated operational (cyclic) conditions.In the first half of the research programme the objective is to produce a crack growth of some centimetres by cyclic loading between a variable minimum pressure and a maximum pressure of about 24 MPa. The total number of load cycles will be approximately 30 000.In the second half of the tests the vessel will be loaded by a number of pressure cycles which correspond to the loading a reactor pressure vessel experiences during 40 years of operation.During the static and cyclic loading acoustic emission monitoring is being made by German and American laboratories.This paper presents details of the vessel, the test loop, results of the nondestructive examinations conducted to quantify the crack depths and results of the acoustic emission monitoring.     

Etude par spectrometrie d'absorption infra-rouge des facteurs influencant la transformation ordre-desordre de ferrites γ lacunaires derivant de l'oxydation de spinelles ferreux

The order-disorder phenomenon in defect γ-spinels of type $\text{(Fe}{}_{\mathrm{<mtext>(8?8y)</mtext><mtext>3</mtext>}}{}^{\mathrm{3+}}\text{M}{}_{\mathrm{<mtext>8y</mtext><mtext>3</mtext>}}{}^{\mathrm{3+}}\text{□}{}_{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}\text{)O}{}_4{}^{\mathrm{2?}}$ and $\text{Fe}{}_{\mathrm{<mtext>(8?2x)</mtext><mtext>3</mtext>}}{}^{\mathrm{3+}}\text{M}{}_{\mathrm{x}}{}^{\mathrm{2+}}\text{□}{}_{\mathrm{<mtext>(1?x)</mtext><mtext>3</mtext>}}\text{)O}{}_4{}^{\mathrm{2?}}$ with M³⁺ = A1³⁺, Cr³⁺ and M²⁺ = Zn²⁺, Co²⁺, Mn²⁺ obtained from ferrous spinels was investigated using IR spectrometry. These compounds possess a vacancy ordering on octahedral sites for substitution extents of less than 0.30 and no ordering has been observed for substitution extent > 0.40. The ordering process is also influenced by the nature and position of the trivalent or divalent cation, particle size, heating temperature and oxidation time.