1,721,083 research outputs found
A case of aneurysm of a primitive persistent sciatic artery: anatomical-clinical aspects and surgical management
No full textAneurysms of the sciatic artery are quite rare. In the literature fewer than 100 cases of gluteal aneurysms have been reported; most have arisen from the superior or inferior gluteal artery; only few cases were aneurysms of an anomalous persistent sciatic artery (6 cases diagnosed angiographically and treated). In our own experience, the overall incidence of this anomaly, in patients undergoing angiography is very low, in the order of 0.025%. In our case the iliac femoral axis showed hypoplasia and required an internal iliac-popliteal bypass. For the location and the propensity atherosclerotic involvement of the persistent sciatic artery, an aneurysm should be considered in all patients with a pulsatile posterior thigh mass, with or not symptoms of peripheral vascular disease
[The impact of coronary disease in patients with obstructive lesions of the carotid arteries]
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A real-time model of a small turbocharged Multijet Diesel engine: application and validation
No full textTheoretical models are useful tools in the design of engine control systems, with applications that range from the definition of optimised management systems, to hardware-in-the-loop testing (HIL) and to model-based control strategies.
To define theoretical models for control-oriented applications, an original library has been built up in Matlab®/Simulink® environment for the simulation of the intake and exhaust systems of automotive turbocharged engines.
Starting from this library, a Mean Value Model (MVM) of a Diesel engine, with variable-geometry turbocharger (VGT), EGR and throttle valve, has been defined and fitted on a small automotive application. The model allowed to simulate in “real-time” engine behaviour: calculated and experimental data are reported and compared in the paper showing a good agreement both in steady and transient operating conditions
Study of Yeast DNA Topoisomerase II and Its Truncation Derivatives by Transmission Electron Microscopy
No full textThe 1429-amino acid residue long yeast DNA topoisomerase II and three of its deletion derivatives, a C-terminal truncation containing residues 1-1202, a 92-kDa fragment spanning residues 410-1202, and an A'-fragment spanning residues 660-1202, were examined by transmission electron microscopy. Analysis of rotary-shadowed images of these molecules shows that the full-length enzyme assumes a tripartite structure, in which a large globular core comprising the carboxyl parts of the dimeric enzyme is connected to a pair of smaller spherical masses comprising the ATPase domains of the enzyme. The linkers bridging the large globular structure and each of the smaller spheres are not visible in most of the images but appear to be sufficiently stiff to keep the relative positions of the connected parts. The angle extended by the pair of spherical masses is variable and falls in a range of 50-100 degrees for the majority of the images. On binding of a nonhydrolyzable ATP analog to the enzyme, this angle is significantly reduced as the two spherical masses swing into contact. These observations, together with results from previous biochemical and x-ray crystallographic studies of the enzyme, provide a sketch of the molecular architecture and conformational states of a catalytically active type II DNA topoisomerase
Natural compounds as therapeutic agents: The case of human topoisomerase ib
Full text linkNatural products are widely used as source for drugs development. An interesting example is represented by natural drugs developed against human topoisomerase IB, a ubiquitous enzyme involved in many cellular processes where several topological problems occur due the formation of supercoiled DNA. Human topoisomerase IB, involved in the solution of such problems relaxing the DNA cleaving and religating a single DNA strand, represents an important target in anticancer therapy. Several natural compounds inhibiting or poisoning this enzyme are under investigation as possible new drugs. This review summarizes the natural products that target human topoisomerase IB that may be used as the lead compounds to develop new anticancer drugs. Moreover, the natural compounds and their derivatives that are in clinical trial are also commented on
REGARDING REDUCTION IN AORTIC ANEURYSM SIZE : EARLY RESULTS AFTER ENDOVASCULAR GRAFT REPLACEMENT
No full textIn the recently published article by Jon S. Matsumura
and collegues (J Vasc Surg 1997;25:113-23), the authors
correlated perigraft leaking diagnosed with contrast com
puter tomographic (CT) scans to long-term changes in the
size of the aorta and aneurysmal segments. Contrast
enhanced CT scans were performed at 6 months and 1 year
after implantation.
- …
