86,901 research outputs found
Complex formation and intermolecular electron tranfer between flavocytochrome b2 in the crystal and cytochrome c
No full textSpatiotemporal characterization of brain infarction by sequential multimodal MR imaging following transient focal ischemia in a Rat model of intra-arterial middle cerebral artery occlusion
No full textObjectives To assess spatiotemporal brain infarction evolu- tion by sequential multimodal magnetic resonance (MR) im- aging in an endovascular model of acute stroke in rats. Materials and methods A microwire was selectively placed in the middle cerebral artery (MCA) in 16 consecutives rats dur- ing 90 minutes occlusion. Longitudinal 7-T MR imaging, in- cluding angiography, diffusion, and perfusion was performed during ischemia, immediately after reperfusion, 3 h and 24 h after subsequent reperfusion.
Results MCA occlusion was complete in 75 % and partial in 18.7 %. Hypoperfusion (mean ± SD) was observed in all ani- mals during ischemia (-59 ± 18 % of contralateral hemisphere, area 31±5 mm2). Infarction volume (mean±SD) was 90 ± 64 mm3 during ischemia and 57 ± 67 mm3 at 24 h. Brain infarction was fronto-parietal cortical in five animals (31 %), striatal in four animals (25 %), and cortico-striatal in seven animals (44 %) at 24 h. All rats survived at 24 h.
Conclusion This model is suitable to neuroprotection studies because of possible acute and close characterization of spatio- temporal evolution of brain infarction by MR imaging
techniques, and evidence of ischemic penumbra, the target of neuroprotection agents. However, optimization of the brain infarct reproducibility needs further technical and neurointerventional tools improvements.
Key points
• Nitinol microwire is MRI compatible allowing spatiotempo-
ral characterization of brain infarction in rats.
• Microwire selective placement in middle cerebral artery al-
lows complete artery occlusion in 75 %.
• A diffusion/perfusion mismatch during arterial occlusion is
observed in 77 % of rats
Hemodynamics, inflammation, vascular remodeling, and the development and rupture of intracranial aneurysms: a review
No full textThe central nervous system is an immunologically active environment where several components of the immune and inflammatory response interact among them and with the constituents of nervous tissue and vasculature in a critically orchestrated manner, influencing physiologic and pathologic processes. In particular, inflammation takes a central role in the pathogenesis of intracranial aneurysms (IAs). The common pathway for aneurysm formation involves endothelial dysfunction and injury, a mounting inflammatory response, vascular smooth muscle cells (VSMCs) phenotypic modulation, extracellular matrix remodeling, and subsequent cell death and vessel wall degeneration. We conducted a literature review (1980-2014) by Medline and EMBASE databases using the searching terms “IA” and “cerebral aneurysm” and further search was performed to link the search terms with the following key words: inflammation, hemodynamic(s), remodeling, macrophages, neutrophils, lymphocytes, complement, VSMCs, mast cells, cytokines, and inflammatory biomarkers. The aim of this review was to summarize the most recent and pertinent evidences regarding the articulated processes of aneurysms formation, growth, and rupture. Knowledge of these processes may guide the diagnosis and treatment of these vascular malformations, the most common cause of subarachnoid hemorrhage, which prognosis remains dismal
Variations on the Author
No full text“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
[Newspaper Clipping: Author Claims Evidence of Second JFK Assassin #1]
No full textNewspaper article titled "Author Claims Evidence of Second JFK Assassin." The article states that author Richard J. Whalen concluded "that there is circumstantial evidence to support the theory of a second assassin in the shooting of President John F. Kennedy.
Also By The Same Author: AKTiveAuthor, a Citation Graph Approach to Name Disambiguation
No full textThe desire for definitive data and the semantic web drive for inference over heterogeneous data sources requires co-reference resolution to be performed on those data. In particular, name disambiguation is required to allow accurate publication lists, citation counts and impact measures to be determined. This paper describes a graph-based approach to author disambiguation on large-scale citation networks. Using self-citation, co-authorship and document source analyses, AKTiveAuthor clusters papers, achieving precision of 0.997 and recall of 0.818 over a test group of eight surname clusters
Nonlinear beam shaping by a cloud of cold Rb atoms
No full textFirst experimental investigations are reported on nonlinear beam shaping due to the interaction between an intense laser beam and a cloud of laser cooled rubidium atoms. Resonant excitation of the F = 3 <-> F'= 4 hyperfine transition is considered. The single-pass interaction through the cold vapor causes an increase in the laser beam intensity in the forward direction (zero transverse wavevector component) when observed in Fourier space, for sufficiently high values of saturation. A qualitative explanation of the observations based on a two-level model for a resonantly excited transition proves acceptable. The observations are compatible with an interpretation based on nonlinear index-induced focusing of an incident beam with curved wavefront, as is used in z-scan measurements. Simple physical considerations allow us to deduce the conditions for the observability of optical patterns in the beam transmitted by a cold atomic cloud. <br/
A 90,000- 200,000 years marine tephra record of Italian volcanic activity in the Central Mediterranean Sea
No full textJohn F. Kennedy telegram to Roosevelt
No full textJersey Homesteads (later the Borough of Roosevelt) was established in the 1930s as an agro-industrial cooperative community. It was established specifically for urban Jewish garment workers, many of whom had emigrated from Europe. President John F. Kennedy sent a telegram to the citizens of Roosevelt, New Jersey, apologizing for not being able to attend the memorial dedication in honor of former President Franklin Delano Roosevelt. (Jersey Homesteads became Roosevelt in 1945 in honor of the president.) President Kennedy expressed his gratitude to the people of Roosevelt for constructing the memorial, and commented that it will serve as a constant reminder of Roosevelt's good works
DWI lesions reversal in posterior circulation stroke after reperfusion: Two illustrative cases and review of the literature
No full textIn acute stroke, diffusion-weighted imaging (DWI) lesions are commonly considered markers of irreversible ischemia, and accurate assessment of DWI lesion volume is crucial in order to establish cutoffs above which reperfusion may not be beneficial. However, some case reports have suggested DWI lesion reversal after reperfusion in posterior circula- tion. We present two cases of brainstem and cerebellar DWI lesions’ reversal after intravenous thrombolysis, and sum- marize currently available data on this issue
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