Intercomparison of scanning probe microscopes

Comparison measurements on reference standards are reported in which 13 partners with different instruments took part. A set of prototype standards which had been produced and calibrated within a European project were used for the measurements. Here, results of measurements on a 240 nm step height standard and a two-dimensional lateral standard with a nominal pitch of 1 μm are reported.     

Association between inflammatory bowel disease and sarcoidosis. Report of two cases and review of the literature

BACKGROUND: Common etiopathogenic factors may explain the association of systemic sarcoidosis with inflammatory bowel disease. METHODS: We report two cases of such an association: one of sarcoidosis that developed 2 years after proctocolectomy for ulcerative colitis and one of sarcoidosis and Crohn's colitis. Factors like increased cellular immunity or circulating immunocomplexes or autoantibodies may have a role. Exogenous agents or familiarity may also be involved. CONCLUSIONS: It is postulated that the association between sarcoidosis and inflammatory bowel disease (both ulcerative colitis and Crohn's disease) does not occur by chance alone and that the two conditions may share some genetic or immunologic alterations. The two diseases, however, follow an independent clinical course.     

Clinical significance of sleep apnea disorders after implantation of a cardioverter-defibrillator in patients with cardiac disease and sustained ventricular tachyarrhythmia

The purpose of our study was to determine the prevalence of sleep related breathing disorders (SRBD) in patients with an implantable cardioverter-defibrillator (ICD) and to evaluate prospectively the possible influence of SRBD on arrhythmia recurrence and circadian arrhythmia variation as well as on cardiac mortality during long-term follow-up. Forty consecutive ICD recipients with cardiac disease and a documented history of spontaneous, life-threatening, ventricular tachyarrhythmias underwent full-night polysomnography and were followed for 2 years. In 16 of 40 patients (40%), SRBD were diagnosed (Apnea/Hypopnea Index (AHI) > 10); in 9 of these 16 patients (56%) central sleep apneas (CSA) occurred (in 8 of these 9 patients in combination with Cheyne-Stokes respiration). Seven of the 16 patients with SRBD (44%) revealed obstructive sleep apneas (OSA). AHI was 32 +/- 15 (12-60) in patients with CSA and 32 +/- 27 (11-86) in patients with OSA. Patients with and without SRBD were comparable concerning left ventricular ejection fraction, NYHA classification, cardiac disease, ICD indication, and concomitant medication. ICD registered ventricular tachyarrhythmias occurred in 10 of 24 patients (42%) without SRBD, in 4 of 9 patients (44%) with CSA, and in 3 of 7 patients (44%) with OSA. The numbers and circadian variation of episodes registered during follow-up in patients without SRBD, with OSA or CSA were comparable (14 +/- 25, median 4 vs 15 +/- 15, median 7 vs 4 +/- 5, median 2.5). The 2-year cardiac mortality was highest in patients with CSA (4/9 (44%) vs. 0/7 patients (0%) with OSA vs 3/24 patients (12.5%) without SRBD. Thus, the prevalence of SRBD in patients with chronic heart failure and a history of malignant ventricular tachyarrhythmias is high (40%) and the occurrence of CSA seems to be predictive for cardiac mortality in these patients. An influence of moderate SRBD on arrhythmia recurrence and circadian variation of spontaneous sustained tachyarrhythmic events could not be demonstrated.     

Doppler ultrasound determination of average blood flow velocity and flow volume in transjugular intrahepatic portosystemic shunt (TIPS)

We evaluated the acute and chronic experimental toxicity of a water extract of saponins from Argania spinosa following oral and intraperitoneal (i.p.) administration in mice (Iops Ofa) and rats (Wistar). The DL50 obtained were 79 mg/kg for the i.p. route and 1,300 mg/kg for the oral route. For the chronic toxicity studies, we administred 100 and 200 mg/kg orally once a day during a 3 month period. There was a decrease in blood sugar in the third month of each therapy. Blood creatinine levels increased, thus evoking a renal pathology. A slight increase in transaminases levels was not significatif. Hematologic parameters were unchanged during the treatment and the histopathologic study showed hepatic glycogen decrease and a focal renal tube deterioration.     

Characterization and Reconstitution of Human Lipoyl Synthase (LIAS) Supports ISCA2 and ISCU as Primary Cluster Donors and an Ordered Mechanism of Cluster Assembly

Lipoyl synthase (LIAS) is an iron–sulfur cluster protein and a member of the radical S-adenosylmethionine (SAM) superfamily that catalyzes the final step of lipoic acid biosynthesis. The enzyme contains two [4Fe–4S] centers (reducing and auxiliary clusters) that promote radical formation and sulfur transfer, respectively. Most information concerning LIAS and its mechanism has been determined from prokaryotic enzymes. Herein, we detail the expression, isolation, and characterization of human LIAS, its reactivity, and evaluation of natural iron–sulfur (Fe–S) cluster reconstitution mechanisms. Cluster donation by a number of possible cluster donor proteins and heterodimeric complexes has been evaluated. [2Fe–2S]-cluster-bound forms of human ISCU and ISCA2 were found capable of reconstituting human LIAS, such that complete product turnover was enabled for LIAS, as monitored via a liquid chromatography–mass spectrometry (LC–MS) assay. Electron paramagnetic resonance (EPR) studies of native LIAS and substituted derivatives that lacked the ability to bind one or the other of LIAS’s two [4Fe–4S] clusters revealed a likely order of cluster addition, with the auxiliary cluster preceding the reducing [4Fe–4S] center. These results detail the trafficking of Fe–S clusters in human cells and highlight differences with respect to bacterial LIAS analogs. Likely in vivo Fe–S cluster donors to LIAS are identified, with possible connections to human disease states, and a mechanistic ordering of [4Fe–4S] cluster reconstitution is evident.     

Dyeing Properties of a Polyamide–Epichlorohydrin Resin

The dyeing behaviour of cured films prepared from a polyamide–epichlorohydrin resin (Hercosett) was examined in orderto obtain a better understanding of the dyeing beha viour of Hercosett–treated wool. The polymer films swell by 500–1000%. The swelling decreases with increasing dye content in the polymer and with increasing temperature. The diffusion of acid dyes into the polymer is extremely fast (D =10^-7 cm²/s), and can be accelerated by the addition of salt. The sorption of the dye is described in terms of a Langmuir isotherm, indicating that an ion–exchange mechanism is operative. The concentration of cationic groups in the polymer is very high (2. 4mo//kg) and does not depend on the curing conditions. The addition of salt reduces the exhaustion of the dyebath. Reactive dyes were found to be bound covalently to the resin. During industrial resin treatment it has been shown that the molecular weight distribution of the Hercosett in the resin bath changes markedly, molecular weight increasing with running time and the spread of values being much narrower. This may explain the variation in the dyeing behaviour of wool fibres that have been treated at different times in the same resin bath.     

Texture discrimination based upon an assumed stochastic texture model

A new approach to texture discrimination is described. This approach is based upon an assumed stochastic model for texture in imagery and is an approximation to the statistically optimum maximum likelihood classifier. The construction and properties of the stochastic texture model are described and a digital filtering implementation of the resulting maximum likelihood texture discriminant is provided. The efficacy of this approach is demonstrated through experimental results obtained with simulated texture data. A comparison is provided with more conventional texture discriminants under identical conditions. The implications to texture discrimination in realworld imagery are discussed.     

The intrinsic XFEM: a method for arbitrary discontinuities without additional unknowns

A new method for treating arbitrary discontinuities in a finite element (FE) context is presented. Unlike the standard extended FE method (XFEM), no additional unknowns are introduced at the nodes whose supports are crossed by discontinuities. The method constructs an approximation space consisting of mesh‐based, enriched moving least‐squares (MLS) functions near discontinuities and standard FE shape functions elsewhere. There is only one shape function per node, and these functions are able to represent known characteristics of the solution such as discontinuities, singularities, etc. The MLS method constructs shape functions based on an intrinsic basis by minimizing a weighted error functional. Thereby, weight functions are involved, and special mesh‐based weight functions are proposed in this work. The enrichment is achieved through the intrinsic basis. The method is illustrated for linear elastic examples involving strong and weak discontinuities, and matches optimal rates of convergence even for crack‐tip applications. Copyright © 2006 John Wiley & Sons, Ltd.