72 research outputs found

    Subintimal angioplasty of chronic total occlusion in iliac arteries: A safe and durable option

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    BackgroundTraditionally, aortobifemoral bypass has been the intervention of choice for iliac artery chronic total occlusions (CTOs). However, it is associated with significant morbidity and mortality, limiting its use in high-risk patients. To reduce procedural risk, subintimal angioplasty (SIA) for femoropopliteal CTO has been utilized by many, but few have extended this endovascular technique to treating iliac artery CTOs. We present our experience with 101 successful SIAs for iliac artery CTOs.MethodsA retrospective review of consecutive patients with iliac artery CTOs treated with subintimal angioplasty from June 2000 to January 2009 was completed. Demographic and risk factor data were obtained, along with procedural data. Primary and secondary patency, survival, freedom from claudication, and limb salvage rates were determined by Kaplan-Meier survival analysis. Univariate and multivariate analyses were completed to identify factors adversely affecting primary patency.ResultsOne hundred twenty patients underwent an attempted SIA of an iliac artery CTO, and 101 iliac artery CTOs were successfully treated, giving a technical success rate of 84%. Technical failure was due to the inability to re-enter the lumen in all cases. Indications for intervention were lifestyle-altering claudication in 64 patients (63%) and critical limb ischemia (CLI), in 37 (37%). Eighty-five patients underwent percutaneous SIA, while 11 patients underwent a combined SIA with surgical outflow procedure. Lesions were classified as TransAtlantic InterSociety Consensus (TASC) B, 39 (39%); TASC C, 27 (27%); and TASC D, 35 (35%). In 82 (81%) lesions, stents were deployed with an average of 1.2 (range, 0-3) stents utilized. A re-entry device was used in 14 (14%) lesions. Major complication rate was 3.0%, with a 30-day mortality rate of 1.0%. Primary and secondary patency rates at 1, 2, and 3 years were 86% and 94%, 76% and 92%, and 68% and 80%, respectively. Survival rate was 67% at 5 years, reflecting the poor health of this cohort. Limb salvage for CLI patients at 1 and 5 years was 97% and 95%, respectively. Freedom from claudication at 1 and 3 years was 89% and 73%. Univariate analysis identified hyperlipidemia, coronary artery disease, and prior surgical bypass in treated limb as factors for loss of primary patency; however, on multivariate analysis, no factors remained statistically significant.ConclusionThis study demonstrates that SIA of iliac CTOs is feasible and can be performed safely and effectively, even in high-risk patients. Excellent patency and limb salvage rates can be achieved. In our experience, the safety and durability of SIA makes it an attractive first-line therapy for iliac artery occlusive disease

    A Fast Algorithm Finding the Shortest Reset Words

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    In this paper we present a new fast algorithm finding minimal reset words for finite synchronizing automata. The problem is know to be computationally hard, and our algorithm is exponential. Yet, it is faster than the algorithms used so far and it works well in practice. The main idea is to use a bidirectional BFS and radix (Patricia) tries to store and compare resulted subsets. We give both theoretical and practical arguments showing that the branching factor is reduced efficiently. As a practical test we perform an experimental study of the length of the shortest reset word for random automata with nn states and 2 input letters. We follow Skvorsov and Tipikin, who have performed such a study using a SAT solver and considering automata up to n=100n=100 states. With our algorithm we are able to consider much larger sample of automata with up to n=300n=300 states. In particular, we obtain a new more precise estimation of the expected length of the shortest reset word ≈2.5n−5\approx 2.5\sqrt{n-5}.Comment: COCOON 2013. The final publication is available at http://link.springer.com/chapter/10.1007%2F978-3-642-38768-5_1

    Projections from the paralemniscal nucleus to the spinal cord in the mouse

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    The present study investigated the projection from the paralemniscal nucleus (PL) to the spinal cord in the mouse by injecting the retrograde tracer fluoro-gold to different levels of the spinal cord and injecting the anterograde tracer biotinylated dextran amine into PL. We found that PL projects to the entire spinal cord with obvious contralateral predominance—420 neurons projected to the contralateral cervical cord and 270 to the contralateral lumbar cord. Fibers from PL descended in the dorsolateral funiculus on the contralateral side and terminated in laminae 5, 6, 7, and to a lesser extent in the dorsal and ventral horns. A smaller number of fibers also descended in the ventral funiculus on the ipsilateral side and terminated in laminae 7, 8 and, to a lesser extent in lamina 9. The present study is the first demonstration of the PL fiber termination in the spinal cord in mammals. The PL projection to the spinal cord may be involved in vocalization and locomotion

    How reproducible are methods to measure the dynamic viscoelastic properties of poroelastic media?

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    There is a considerable number of research publications on the acoustical properties of porous media with an elastic frame. A simple search through the Web of Scienceâ„¢ (last accessed 21 March 2018) suggests that there are at least 819 publications which deal with the acoustics of poroelastic media. A majority of these researches require accurate knowledge of the elastic properties over a broad frequency range. However, the accuracy of the measurement of the dynamic elastic properties of poroelastic media has been a contentious issue. The novelty of this paper is that it studies the reproducibility of some popular experimental methods which are used routinely to measure the key elastic properties such as the dynamic Young's modulus, loss factor and Poisson ratio of poroelastic media. In this paper, fourteen independent sets of laboratory measurements were performed on specimens of the same porous materials. The results from these measurements suggest that the reproducibility of this type of experimental method is poor. This work can be helpful to suggest improvements which can be developed to harmonize the way the elastic properties of poroelastic media are measured worldwide

    Quantifying Sources of Variability in Infancy Research Using the Infant-Directed-Speech Preference

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    Psychological scientists have become increasingly concerned with issues related to methodology and replicability, and infancy researchers in particular face specific challenges related to replicability: For example, high-powered studies are difficult to conduct, testing conditions vary across labs, and different labs have access to different infant populations. Addressing these concerns, we report on a large-scale, multisite study aimed at (a) assessing the overall replicability of a single theoretically important phenomenon and (b) examining methodological, cultural, and developmental moderators. We focus on infants’ preference for infant-directed speech (IDS) over adult-directed speech (ADS). Stimuli of mothers speaking to their infants and to an adult in North American English were created using seminaturalistic laboratory-based audio recordings. Infants’ relative preference for IDS and ADS was assessed across 67 laboratories in North America, Europe, Australia, and Asia using the three common methods for measuring infants’ discrimination (head-turn preference, central fixation, and eye tracking). The overall meta-analytic effect size (Cohen’s d) was 0.35, 95% confidence interval = [0.29, 0.42], which was reliably above zero but smaller than the meta-analytic mean computed from previous literature (0.67). The IDS preference was significantly stronger in older children, in those children for whom the stimuli matched their native language and dialect, and in data from labs using the head-turn preference procedure. Together, these findings replicate the IDS preference but suggest that its magnitude is modulated by development, native-language experience, and testing procedure

    The Neurotoxicity of DOPAL: Behavioral and Stereological Evidence for Its Role in Parkinson Disease Pathogenesis

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    BACKGROUND: The etiology of Parkinson disease (PD) has yet to be fully elucidated. We examined the consequences of injections of 3,4-dihydroxyphenylacetaldehyde (DOPAL), a toxic metabolite of dopamine, into the substantia nigra of rats on motor behavior and neuronal survival. METHODS/PRINCIPAL FINDINGS: A total of 800 nl/rat of DOPAL (1 µg/200 nl) was injected stereotaxically into the substantia nigra over three sites while control animals received similar injections of phosphate buffered saline. Rotational behavior of these rats was analyzed, optical density of striatal tyrosine hydroxylase was calculated, and unbiased stereological counts of the substantia nigra were made. The rats showed significant rotational asymmetry ipsilateral to the lesion, supporting disruption of dopaminergic nigrostriatal projections. Such disruption was verified since the density of striatal tyrosine hydroxylase decreased significantly (p<0.001) on the side ipsilateral to the DOPAL injections when compared to the non-injected side. Stereological counts of neurons stained for Nissl in pars compacta of the substantia nigra significantly decreased (p<0.001) from control values, while counts of those in pars reticulata were unchanged after DOPAL injections. Counts of neurons immunostained for tyrosine hydroxylase also showed a significant (p=0.032) loss of dopaminergic neurons. In spite of significant loss of dopaminergic neurons, DOPAL injections did not induce significant glial reaction in the substantia nigra. CONCLUSIONS: The present study provides the first in vivo quantification of substantia nigra pars compacta neuronal loss after injection of the endogenous toxin DOPAL. The results demonstrate that injections of DOPAL selectively kills SN DA neurons, suggests loss of striatal DA terminals, spares non-dopaminergic neurons of the pars reticulata, and triggers a behavioral phenotype (rotational asymmetry) consistent with other PD animal models. This study supports the "catecholaldehyde hypothesis" as an important link for the etiology of sporadic PD
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