1,721,044 research outputs found
Investigating protein structure and dynamics through wide-angle X-ray solution scattering
Full text linkWide-angle X-ray scattering (WAXS) is a powerful tool that can be used to gain information on the structure and dynamics of proteins and other biomolecules in solution. Improved methods for the calculation of WAXS patterns from available or putative protein models allow to better exploit the structural information contained in the experimental data. These methods, together with recent applications of static and time-resolved WAXS, are briefly reviewed
Hysteresis in the temperature dependence of the IR bending vibration of deeply cooled confined water
No full textUsing Fourier Transform Infrared (FTIR) spectroscopy, we investigate the temperature dependence of the bending vibrations of water confined in the pores of a silica hydrogel in the temperature interval of 270-180 K. We also investigate the presence of thermal hysteresis by cooling and reheating temperature scans. The results clearly show the presence, at about 230 K, of a crossover in the temperature dependence of the IR spectra; moreover, the presence of hysteresis is clearly demonstrated. By comparing FTIR data with neutron diffraction data and previous calorimetric data on the same samples, we conclude that the crossover and the hysteretical behavior do not involve a water glass transition or crystallization but are related to a first-order-like liquid-liquid transition
Huge aortic pseudoaneurysm due to detachment of both coronary buttons after the modified Bentall procedure
Full text linkA 59-year-old female presented with a huge aortic preudoaneurysm (maximum diameter of 9 cm) 12 years following a modified Bentall procedure with a 23mm mechanical conduit (Figures 1,2). At reoperation the pseudoaneurysm was found to be due to complete dehiscence of both coronary ostial anastomoses, compressing the right cardiac sections
Discrete subaortic stenosis associated with calcific aortic stenosis in the elderly
No full textDiscrete subaortic stenosis associated with calcific aortic stenosis in the elderl
Entrapment of a coronary stent in the left main trunk: An easy method for surgical removal
No full textThe use of an intracoronary stent is usually indicated after the acute closure of a coronary vessel following percutaneous transluminal coronary angioplasty. Plaque disruption and dissection, with subsequent spasm and thrombosis, can be contained by this device. In the reported case, acute closure of the left anterior descending coronary artery and of a diagonal branch were caused by the entrapment of a stent proximal to the coronary lesion that it was supposed to treat. An emergency coronary artery bypass graft procedure was required together with removal of the device because of the impending closure of the left main trunk (the site of the stent entrapment). This was successfully performed by means of an easy method, which did not require direct incision of the left main trunk. The less invasive procedure described simplified the operation and probably played an important role in its favorable outcome
Delayed papillary muscle rupture following repair of post-infarction ventricular septal defect
No full textInfluence of Cardiovascular Risk Factors on Aortic Wall Motion After Repair of Type A Aortic Dissection: An Electrocar- diography-Gated Computed Tomography Study
Full text linkBackground: We aimed to evaluate size changes of the thoracic aorta during the cardiac cycle with dynamic computed tomographic angiography (CTA) at specific anatomic landmarks in patients who previously under- went ascending aorta repair because of type A dissec- tion, and to correlate aortic wall motion with several cardiovascular risk factors. Methods: From December 2008 to December 2010, 18 patients (14 men and 4 women, mean age 64 12 years) with previous aortic repair underwent electrocardiography-gated CTA fol- low-up. Aortic systolic and diastolic diameter and cross-sectional area were measured at 4 levels: 1 cm proximal (level A) and 1 (B), 3 (C), and 10 cm (D) distal to the origin of the left subclavian artery. Results were assessed according to age and presence of diabetes, hypertension, and smoking. Results: This morpho-functional evaluation of aortic wall motion demonstrated a significant influence (P < 0.05) of hy- pertension at level A and D and diabetes at level D. Smoking had a borderline significance at level C and D. No significant correlation with age was evident, with results not significantly different in patients < 55 and > 55 years. Conclusions: Smoking, diabetes, and hyper- tension play a role in impairing aortic size variations. These variations might predict wall structural altera- tions due to cardiovascular risk factors before they
become morphologically evident. This might influence timing of surveillance following repair of acute dissec- tion, allowing it to be specifically tailored for any single
subject
Going 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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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