Endovascular technique in aortic aneurysm. A promising alternative to open surgery]

Reports of human immunodeficiency virus-associated nephropathy (HIVAN) occurring in Hispanics, females and heterosexuals are scarce. We reviewed 858 charts from our total HIV population to determine the prevalence and epidemiology of HIVAN at our center, and to evaluate the renal and patient survival among individual groups, according to race, sex and HIV risk factor. The prevalence of HIVAN was low (1.9%), relative to other centers (4-13%). Although Hispanics accounted for 56% of the HIV population, only 38% of HIVAN patients were Hispanic. The absolute risk of HIVAN in blacks was 3. 6%, and in Hispanics was 1.3%. The relative risk of blacks vs. Hispanics was 2.8% (p < 0.04). Women and men were represented equally in both the HIVAN and HIV populations. The mean (+/- SE) rate of decline in glomerular filtration rate was 3.7 +/- 0.9 ml/min/month, and patient survival following the onset of HIVAN was 23.6 +/- 4.8 months. We found no difference in renal or patient survival between individual groups. In summary, the risk of HIVAN in Hispanics is similar to that for whites. Male sex is not an independent risk factor. Both renal and patient survival are similar in blacks and Hispanics, and in men compared to women.     

Mechanical properties of sawn timber from Norway spruce

Picea abies ) of three different cross sectional sizes: 38×89 mm², 38×140 mm², and 38×184 mm². Specific material characteristics for the lumber are presented. The tests also enabled comparison between results from two testing methodologies. The mean value for the modulus of elasticity established from the dynamic tests was found to be approximately 10% higher than the corresponding value established from static tests. The statistical correlation between statically and dynamically established moduli is very strong. The dynamic E modulus was found to be as good a strength predictor as the static E modulus. Cross sectional size and the existence of the pith in the sawn lumber were found to significantly influence the material properties. In general terms, it was found that deeper beams correspond to lower values for the E modulus and for the bending strength. The reason for this tendency is believed to be a combination of a volumetric effect (in the case of strength) and a phenomenon related to the log selection and sawing process in the mills. Lumber that comprises the pith has been found to have generally lower values of the E modulus and bending strength while the shear modulus is higher, compared to lumber without pith sawn further out in the log.

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Picea abies ) wurden dynamische und statische Prüfungen vorgenommen. Die Proben hatten drei verschiedene Querschnitte: 38×89 mm², 38×140 mm² und 38×184 mm². Anhand der vorgelegten Ergebnisse wurden auch zwei Prüfmethoden verglichen. Die Mittelwerte der dynamischen MOE-Prüfung lagen etwa 10% h?her als die statisch ermittelten Werte. Die Korrelation beider MOE-Werte ist sehr streng. Beide Werte k?nnen zur Vorhersage der Festigkeit verwendet werden. Der Querschnitt und die Anwesenheit von Markanteilen beeinflussen das Ergebnis wesentlich. Je tiefer die Balken waren d.h. je n?her sie der Markr?hre lagen, desto geringer waren E-Modul und Biegefestigkeit. Die Gründe dafür werden teils einem Volumeneffekt zugeschrieben (im Falle der Festigkeit), teils auf das Auswahlverfahren der St?mme im S?gebetrieb zurückgeführt. Schnittholz mit Markanteil hatte allgemein. einen geringeren E-Modul und niedrigere Biegefestigkeit als Proben aus ?u?eren Stammbereichen; die Scherfestigkeit lag dagegen h?her.

     

Magnetic resonance imaging and MR angiography of endoluminally treated abdominal aortic aneurysms

Molecular biology has provided various new insights into the mechanisms operative in the pathogenesis of rheumatoid arthritis. Reflecting the unique character of rheumatoid synovium, advances have been achieved addressing the molecular changes taking place at the area of interaction between the aggressively growing synovium and the articular cartilage and bone. Key issues in the review period addressing this interaction were hyperplasia of rheumatoid arthritis synovium, mechanisms of activation and cell cycle regulation of synovial fibroblasts, pathways of synovial attachment to cartilage and bone, and the regulation of matrix-degrading enzymes.     

Low-jitter and high-power 40-GHz all-active mode-locked lasers

A novel design strategy for the epitaxial structure of monolithic mode-locked semiconductor lasers is presented. Using an all-active design, we fabricate 40-GHz lasers generating 2.8-ps almost chirp-free pulses with record low high-frequency jitter and more than 7-mW fiber coupled output power.     

Glucagon-like peptide-1 reduces hepatic glucose production indirectly through insulin and glucagon in humans

The effect of glucagon-like peptide-1 (GLP-1) on hepatic glucose production and peripheral glucose utilization was investigated with or without infusion of somatostatin to inhibit insulin and glucagon secretion in 13 healthy, non-diabetic women aged 59 years. After 120 min 3-(3)H-glucose infusion, GLP-1 was added (4.5 pmol kg(-1) bolus + 1.5 pmol kg(-1) min(-1)). Without somatostatin (n = 6), GLP-1 decreased plasma glucose (from 4.8 +/- 0.2 to 4.2 +/- 0.3 mmol L(-1), P = 0.007). Insulin levels were increased (48 +/- 3 vs. 243 +/- 67 pmol L(-1), P = 0.032), as was the insulin to glucagon ratio (P = 0.044). The rate of glucose appearance (Ra) was decreased (P = 0.003) and the metabolic clearance rate of glucose (MCR) was increased during the GLP-1 infusion (P = 0.024 vs. saline). Also, the rate of glucose disappearance (Rd) was reduced during the GLP-1 infusion (P = 0.004). Since Ra was reduced more than Rd, the net glucose flow was negative, which reduced plasma glucose. Somatostatin infusion (500 microg h(-1), n = 7) abolished the effects of GLP-1 on plasma glucose, serum insulin, insulin to glucagon ratio, Ra, Rd, MCR and net glucose flow. The results suggest that GLP-1 reduces plasma glucose levels mainly by reducing hepatic glucose production and increasing the metabolic clearance rate of glucose through indirectly increasing the insulin to glucagon ratio in healthy subjects.     

High-efficiency broad-area single-quantum-well lasers with narrow single-lobed far-field patterns prepared by molecular beam epitaxy

Broad-area single-quantum-well graded-index waveguide separate-confinement heterostructure lasers were fabricated by molecular beam epitaxy. A high external quantum efficiency of 79% and stable, single-lobed far-field patterns with a beam divergence as narrow as 0.8° (1.9 times diffraction limit) for a 100 ?m-wide laser were obtained under pulsed conditions.     

Interleukin-2 and -4 induce resistance of granulocyte-macrophage colony-stimulating factor to corticosteroids

In vitro pretreatment of human mononuclear blood cells with a combination of interleukin-2 and interleukin-4 decreases corticosteroid receptor affinity and reduces the anti-proliferative effects of corticosteroids. Similar abnormalities have been observed in mononuclear blood cells of steroid-resistant asthmatics. In vitro steroid resistance was induced by 48 h pretreatment of mononuclear blood cells from healthy individuals (n = 10) with interleukin-2 and interleukin-4 (500 Units (U)/ml). The effects of three structurally different corticosteroids (10(-7)-10(-11) M) on lipopolysaccharide-stimulated (10 ng/ml; 20 h) production of granulocyte-macrophage colony-stimulating factor (GM-CSF) were examined. GM-CSF production was efficiently inhibited by all three corticosteroids in the control cultures. Cortivazol was significantly more potent (IC50 = 3 x 10(-11) M) than budesonide and tipredane (IC50 = 2.5 x 10(-10) M and IC50 = 2 x 10(-10) M, respectively). However. interleukin-2 and interleukin-4 pretreatment counteracted the inhibitory effects of all three corticosteroids to a similar degree. The results highlight the importance of interleukin-2 and interleukin-4 in the induction of steroid resistance, since pretreatment of mononuclear blood cells with these cytokines impaired corticosteroid inhibition of GM-CSF production.     

Real-time fluorescence imaging of isotachophoretic preconcentration for capillary electrophoresis

Real-time studies of the dynamic processes that take place during isotachophoresis (ITP) were performed. The experimental arrangement utilized was a real-time fluorescence imaging system based on a dye laser at 488 nm, pumped by a XeCl excimer laser. Fluorescence emitted from the migrating sample molecules was recorded by an image-intensified, thermoelectrically cooled CCD camera. The camera signals were processed by a computer and displayed on a screen in real time, allowing the ITP concentration to be monitored continuously. Real-time analysis provided additional information concerning ITP hardly obtainable using conventional detection systems or by theoretical calculations. Such experimental data can be evaluated and be compared with theoretical calculations. Information obtained by this detection technique is useful if ITP is to be used, for example as an on-line preconcentration technique in combination with capillary zone electrophoresis.     

XFEM‐based element subscale refinement for detailed representation of crack propagation in large‐scale analyses

In the present paper, we address the delicate balance between computational efficiency and level of detailing at the modelling of ductile fracture in thin‐walled structures. To represent the fine‐scale nature of the ductile process, we propose a new extended finite element method‐based enrichment of the displacement field to allow for crack tips that end or kink within an element. The idea is to refine the crack tip element locally in a way such that the macroscale node connectivity is unaltered. This allows for a better representation of the discontinuous kinematics without affecting the macroscale solution procedure, which would be a direct consequence of a regular mesh refinement. The method is first presented in a general 3D setting, and thereafter, it is specialised to shell theory for the modelling of crack propagation in thin‐walled structures. The paper is concluded by a number of representative examples showing the accuracy of the method. We conclude that the ideas proposed in the paper enhance the current methodology for the analysis of ductile fracture of thin‐walled large‐scale structures under high strain rates. Copyright © 2016 John Wiley & Sons, Ltd.     

Mesh objective continuum damage models for ductile fracture

During machining processes, the work piece material is subjected to high deformation rates, increased temperature, large plastic deformations, damage evolution and fracture. In this context the Johnson‐Cook failure model is often used even though it exhibits pathological mesh size dependence. To remove the mesh size sensitivity, a set of mesh objective damage models is proposed based on a local continuum damage formulation combined with the concept of a scalar damage phase field. The first model represents a mesh objective augmentation of the well‐established element removal model, whereas the second one degrades the continuum stress in a smooth fashion. Plane strain plate and hat specimens are used in the finite element simulations, with the restriction to the temperature and rate independent cases. To investigate the influence of mesh distortion, a structured and an unstructured meshes were used for the respective specimen. For structured meshes, the results clearly show that the pathological mesh size sensitivity is removed for both models. When considering unstructured meshes, the mesh size sensitivity is more complex as revealed by the considered hat‐specimen shear test. Nevertheless, the present work indicates that the proposed models can predict realistic ductile failure behaviors in a mesh objective fashion. Copyright © 2015 John Wiley & Sons, Ltd.