Reduction in Renal Function After Renal Arteriography and After Renal Artery Angioplasty

AbstractObjective: to investigate the incidence and risk factors for renal function deterioration after renal angiography and angioplasty or stenting.Methods: a retrospective study of 85 consecutive patients undergoing selective renal artery arteriography (n=53) or renal artery angioplasty % (PTRA) stenting (n=32) for renal artery stenosis. Multivariate logistic regression analysis was used to determine independent predictors of deterioration of renal function, defined as an increase of serum creatinine by at least one third within 24h.Results: deterioration of renal function occurred in 13 patients (15%), [8/53 (15%) after angiography and 5/32 (16%) after PTRA/stenting]. Only pre-existing renal impairment (se-creatinine≥177μmol/l) (Odds ratio: 40; 95% confidence interval 1.2–72, p=0.02) and administered dosage of contrast agent (more than 225ml) (OR 67; 95% CI1 1.8–100, p=0.02) were independently associated with renal function deterioration.Conclusion: transient renal dysfunction after renal artery angiography or PTRA/stenting occurs in about 15% of patients, but persistent renal failure is uncommon. Pre-existing renal impairment and amount of contrast agent are independent risk factors. Endovascular treatment of renal artery stenosis is not associated with a higher risk of renal deterioration compared to selective renal angiography

Neutron Radiographic Study of the Effect of Heat-Driven Water Transport on the Tensile Strength of Bentonite-Bonded Moulding Sand

Wet tensile testing is a common method to assess the stability of bentonite bonded moulding sands. For wet tensile testing, a specimen is first heated from above in order to simulate heat-driven moisture transport induced by the casting process. Then, tensile stress is applied until rupture. In this study, neutron radiography imaging was applied to moulding sands in-situ during heating and wet tensile testing in order to investigate the effects of water kinematics on the tensile strength. Neutron radiography allowed the localization of the rupture plane and the quantitative determination of the local water content with sub-mm resolution. Quantification of the temperature at the rupture plane and of the heat kinematics within the specimen was accomplished by temperature measurements both in-situ and ex-situ. In this way, experimental data correlating the wet tensile strength with the specific conditions of moulding sands at the rupture plane were obtained for the first time. Series of experiments with different initial sand moisture contents were conducted. The results show that the weakest location within a sand profile can be pinpointed at the interface between evaporation and condensation zone (i.e., at the 100 °C isotherm), where water vaporisation starts and the water bridges connecting the sand grains collapse. This weakest location has maximum strength, if the local water content at the rupture plane is between 5 and 9 wt.%. Less water leads to a strong decrease of wet tensile strength. More water requires an initial water content above 5 wt.%, which leads to a decrease of the tensile strength of the unheated sand

UIS BW. Umweltinformationssystem Baden-Württemberg. F+E-Vorhaben MAF-UIS. Moderne anwendungsorientierte Forschung und Entwicklung für Umweltinformationssysteme. Phase II 2012/14. (KIT Scientific Reports ; 7665)

Das F+E-Vorhaben MAF-UIS des Ministeriums für Umwelt, Klima und Energiewirtschaft Baden-Württemberg setzt auf eine breite Kooperation mit Partnern aus Verwaltung, Wissenschaft und Wirtschaft zum gemeinsamen Ausbau der behördlichen Umweltinformationssysteme. Geprägt wurde die hier beschriebene zweite Phase von der Erstellung der Studie WebUIS 3.0 und der Entwicklung mobiler Anwendungen

Dissociable Perceptual Effects of Visual Adaptation

Neurons in the visual cortex are responsive to the presentation of oriented and curved line segments, which are thought to act as primitives for the visual processing of shapes and objects. Prolonged adaptation to such stimuli gives rise to two related perceptual effects: a slow change in the appearance of the adapting stimulus (perceptual drift), and the distortion of subsequently presented test stimuli (adaptational aftereffects). Here we used a psychophysical nulling technique to dissociate and quantify these two classical observations in order to examine their underlying mechanisms and their relationship to one another. In agreement with previous work, we found that during adaptation horizontal and vertical straight lines serve as attractors for perceived orientation and curvature. However, the rate of perceptual drift for different stimuli was not predictive of the corresponding aftereffect magnitudes, indicating that the two perceptual effects are governed by distinct neural processes. Finally, the rate of perceptual drift for curved line segments did not depend on the spatial scale of the stimulus, suggesting that its mechanisms lie outside strictly retinotopic processing stages. These findings provide new evidence that the visual system relies on statistically salient intrinsic reference stimuli for the processing of visual patterns, and point to perceptual drift as an experimental window for studying the mechanisms of visual perception

Maximum-likelihood absorption tomography

Maximum-likelihood methods are applied to the problem of absorption tomography. The reconstruction is done with the help of an iterative algorithm. We show how the statistics of the illuminating beam can be incorporated into the reconstruction. The proposed reconstruction method can be considered as a useful alternative in the extreme cases where the standard ill-posed direct-inversion methods fail.Comment: 7 pages, 5 figure

Nasszugfestigkeitsprüfungen in der Neutronenradiografie

Bentonitgebundene Formsande gehören aufgrund ihrer Umweltfreundlichkeit und Wiederverwendbarkeit zu den wichtigsten Formstoffen in Gießereien. Es liegt daher nahe, das Verhalten und die Eigenschaften dieser Formsande genau zu untersuchen. Im durchgeführten Forschungsprojekt wurden die Nasszugfestigkeiten von Formstoffproben in Echtzeit während einer Durchstrahlung mit Neutronen gemessen. Dabei konnten auch der Riss abgebildet und die lokalen Wassergehalte ermittelt werden

Comparison of a one-time educational intervention to a teach-to-goal educational intervention for self-management of heart failure: design of a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Heart failure (HF) is common, costly and associated with significant morbidity and poor quality of life, particularly for patients with low socioeconomic status. Self-management training has been shown to reduce HF related morbidity and hospitalization rates, but there is uncertainty about how best to deliver such training and what patients benefit. This study compares a single session self-management HF training program against a multiple session training intervention and examines whether their effects differ by literacy level.</p> <p>Methods/Design</p> <p>In this randomized controlled multi-site trial, English and Spanish-speaking patients are recruited from university-affiliated General Internal Medicine and Cardiology clinics at 4 sites across the United States. Eligible patients have HF with New York Heart Association class II-IV symptoms and are prescribed a loop diuretic. Baseline data, including literacy level, are collected at enrollment and follow-up surveys are conducted at 1, 6 and 12 months</p> <p>Upon enrollment, both the control and intervention groups receive the same 40 minute, literacy-sensitive, in-person, HF education session covering the 4 key self-management components of daily self assessment and having a plan, salt avoidance, exercise, and medication adherence. All participants also receive a literacy-sensitive workbook and a digital bathroom scale. After the baseline education was completed, patients are randomly allocated to return to usual care or to receive ongoing education and training. The intervention group receives an additional 20 minutes of education on weight and symptom-based diuretic self-adjustment, as well as periodic follow-up phone calls from the educator over the course of 1 year. These phone calls are designed to reinforce the education, assess participant knowledge of the education and address barriers to success.</p> <p>The primary outcome is the combined incidence of all cause hospitalization and death. Secondary outcomes include HF-related quality of life, HF-related hospitalizations, knowledge regarding HF, self-care behavior, and self-efficacy. The effects of each intervention will be stratified by patient literacy, in order to identify any differential effects.</p> <p>Discussion</p> <p>Enrollment of the proposed 660 subjects will continue through the end of 2009. Outcome assessments are projected to be completed by early 2011.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov <url>http://www.clinicaltrials.gov/</url> NCT00378950</p

Crystal structures of self-assembled nanotubes from flexible macrocycles by weak interactions

8 páginas, 7 figuras, 2 tablas, 2 esquemas.Herein we report the crystal structures of tubular self-assemblies of flexible macrooligolides. The assembly is driven by the propensity of the macrocycles to create nearly flat structures displaying a void space within them and the cooperativity of weak directional interactions such as dipole–dipole interactions and CH***Ohydrogen bonds and non-directional interactions such as van der Waals contacts. The significance of the stereochemistry and the size of the cavity in the formation of the nanotubes are also studied.This research was supported by the Spanish MICINN-FEDER (CTQ2008-03334/BQU, CTQ2008-06806-C02-01/BQU and CTQ2008-06754-C04-01/PPQ), the MSC (RTICC RD06/0020/ 1046) and the Canary Islands FUNCIS (PI 01/06).Peer reviewe

Characterization of silicon carbide surfaces of 6H- 15R- and 3Cpolytypes by optical second-harmonic generation in comparison with X-ray diffraction techniques

Abstract. Second-harmonic (SH) generation is a versatile method applicable to in-situ characterization of even noncentrosymmetric media like silicon carbide (SiC). In particular, the azimuthal rotational anisotropy of the SH response from SiC observed in reflection allows identification of various polytypes. The nonlinear-optical results are compared to X-ray diffraction data. The abundance of information obtained through the SH studies makes characteristic fingerprinting of the 6H, 15R, and 3C polytypes of SiC is possible. The spatial resolution of the optical sampling was about 50 µm in the lateral direction with a typical penetration depth of 100 nm for the fundamental radiation. Defect regions of different crystallographic structures in large SiC samples were identified by observing the spatially resolved dependence of the SH intensity. 42.65.Nx; 78.66; 42.70.N Silicon carbide (SiC) is a widely studied semiconductor that crystallizes in over 200 known polytypes. The most common structure is α-SiC, which consists of a mixture of hexagonal polytypes (6H, 4H) and the rhombohedral polytype 15R PACS: As already demonstrated in other studies on centrosymmetric materials like silicon, second-harmonic generation (SHG) has proved to be a sensitive tool for studying a large variety of surface and interface structural and electronic properties. Although SHG from non-centrosymmetric materials is not restricted to the surface but is also possible in the bulk material SHG studies in reflection geometry provide substantial crystallographic information on the near-surface region. The generation depth of the second-harmonic (SH) radiation detected in reflection of approximately λ/2π, where λ is the fundamental wavelength, allows higher surface specificity, as compared to the typical interaction lengths of several micrometers in conventional X-ray diffraction techniques in back-reflection geometry (X-ray examination of SiC cf. [4]). The tensorial properties of the second-order susceptibility, which characterizes the SHG effect, provide information on the crystal structure in case of non-centrosymmetric materials in the near-surface region by investigating its azimuthal rotational anisotropy. Although studies on non-centrosymmetric gallium arsenide (GaAs) demonstrated sensitively surface reconstruction changes In the present work, we demonstrate that SHG is a versatile tool to characterize the crystalline structure of SiC. By investigating the rotational anisotropy of the SH response of various polytypes of SiC, we could fingerprint the most important species 6H, 15R and 3C, which are revealed by different crystalline structures. We were also able to distinguish between bulk and surface contributions to the SH signal from cubic and hexagonal SiC by differences in the rotationa