109 research outputs found
Circuit Lower Bounds Collapse Relativized Complexity Classes
No full textSince the publication of Furst, Saxe, and Sipser's seminal paper connecting AC 0 with the polynomial hierarchy [FSS84], it has been well known that circuit lower bounds allow you to construct oracles that separate complexity classes. We will show that similar circuit lower bounds allow you to construct oracles that collapse complexity classes. For example, based on Hastad's parity lower bound, we construct an oracle such that P = PH ae \PhiP = EXP. Dept. of Electrical Engineering and Computer Science, University of Illinois at Chicago, Rm. 1120, SEO Building, M/C 154, 851 S. Morgan St., Chicago, IL 60607-7053. [email protected]. www.eecs.uic.edu/¸beigel. Part of this work was performed while this author was at the Department of Computer Science, UMIACS, and the Human--Computer Interaction Laboratory, University of Maryland, College Park, on sabbatical from the Yale University Department of Computer Science. Supported in part by the National Science Foundation under grants CCR-895..
Heart failure with supranormal ejection fraction: clinical characteristics and outcomes compared to mildly reduced and preserved ejection fraction
No full textBackground: Little is known about the recently emerging entity, heart failure with supranormal ejection fraction (HFsnEF). Objective: To describe the clinical characteristics and outcome of HFsnEF, compared to HF with mildly reduced EF (HFmrEF) and HF with preserved EF (HFpEF) patients. Design: A single center retrospective analysis. Patients: Hospitalized and ambulatory heart failure (HF) patients who underwent echocardiography with left ventricular ejection fraction (LVEF) > 40%. Main measures: Clinical and echocardiographic parameters, hospitalization rates and mortality. Key results: A total of 6,202 patients (mean age 81.4 ± 14.1 years, 52% females) were analyzed: 750 in the HFmrEF group (LVEF 41–49%), 4360 in the HFpEF group (LVEF 50–64%), and 1092 in the HFsnEF group (LVEF ≥ 65%). Patients were followed for a median of 32 (11–65) months. HFsnEF patients were older, predominantly female, exhibited higher hypertension prevalence, more severe LV hypertrophy, smaller LV dimensions, and higher filling pressures compared to the other groups (p < 0.001 for all). These features were consistent in both hospitalized and ambulatory patients. In a univariable model, HFsnEF patients had higher mortality rates compared to HFmrEF and HFpEF patients (HR 1.258, 95% CI 1.117–1.418; p < 0.001 and HR 1.112, 95% CI 1.023–1.208; p = 0.012, respectively). However, in a multivariable model, adjusted for age, sex, comorbidities, and echocardiographic parameters, there was no significant difference in the mortality rates between all groups. The total hospitalization rate was similar between the HFpEF and HFsnEF groups, and lower in the HFmrEF group (p = 0.022). However, the HFsnEF group had the lowest rate of HF-related hospitalizations (p = 0.002). Conclusion: HFsnEF represents a group of patients with a distinct clinical and echocardiographic profile accompanied by worse outcomes, likely mediated by older age and a higher comorbidity burden, compared to HFmrEF and HFpEF. Therefore, the supranormal EF may serve as a marker rather than an independent prognostic factor
Regulation of heparanase expression in coronary artery disease in diabetic, hyperlipidemic swine
Get PDFObjective
Enzymatic degradation of the extracellular matrix is known to be powerful regulator of atherosclerosis. However, little is known about the enzymatic regulation of heparan sulfate proteoglycans (HSPGs) during the formation and progression of atherosclerotic plaques.
Methods and results
Swine were rendered diabetic through streptozotocin injection and hyperlipidemic through a high fat diet. Arterial remodeling and local endothelial shear stress (ESS) were assessed using intravascular ultrasound, coronary angiography and computational fluid dynamics at weeks 23 and 30. Coronary arteries were harvested and 142 arterial subsegments were analyzed using histomorphologic staining, immunostaining and real time PCR. Heparanase staining and activity was increased in arterial segments with low ESS, in lesions with thin cap fibroatheroma (TCFA) morphology and in lesions with severely degraded internal elastic laminae. In addition, heparanase staining co-localized with staining for CD45 and MMP-2 within atherosclerotic plaques. Dual staining with gelatinase zymography and heparanase immunohistochemical staining demonstrated co-localization of matrix metalloprotease activity with heparanase staining. A heparanase enzymatic activity assay demonstrated increased activity in TCFA lesions, subsegments with low ESS and in macrophages treated with oxidized LDL or angiotensin II.
Conclusions
Taken together, our results support a critical role for heparanase in the development of vulnerable plaques and suggest a novel therapeutic target for the treatment of atherosclerosis.Novartis (Firm)Boston Scientific CorporationNational Institutes of Health (U.S.) (Grant R01 GM49039
Einfluß der Faktoren Tageszeit und Elektrodenlage und ihre Prüfung bei automatischer EEG-Auswertung
No full textDer Studie liegt ein zweimonatiges Experiment zugrunde, in welchem zu verschiedenen Tageszeiten das EEG der Probanden kurzzeitig registriert wurde. Nach der automatischen Extraktion der Dominanten Frequenz aus dem EEG wurde der Einfluß der Hauptwirkungen Tageszeit, Langzeit und Elektrodenlage sowie der Wechselwirkung Tageszeit/Langzeit bei Anwendung des korrekten F-Tests von LE ROY untersucht.Im Anhang wurde der F-Test eines gemischten Modells von fünf Faktoren entwickelt und die vereinfachte Regel von DUDECK für partiell-hierarchische Modelle erläutert.</jats:p
Almost-everywhere complexity hierarchies for nondeterministic time
No full textWe present an a.e. complexity hierarchy for nondeterministic time, and show that it is essentially the best result of this sort that can be proved using relativizable proof techniques.Technical report LCSR-TR-18
Should the Guidelines for the Assessment of the Severity of Functional Mitral Regurgitation Be Redefined?
No full textAugmented Expression and Activity of Extracellular Matrix-Degrading Enzymes in Regions of Low Endothelial Shear Stress Colocalize With Coronary Atheromata With Thin Fibrous Caps in Pigs
Get PDFBackground—The molecular mechanisms that determine the localized formation of thin-capped atheromata in the coronary arteries remain unknown. This study tested the hypothesis that low endothelial shear stress augments the expression of matrix-degrading proteases and thereby promotes the formation of thin-capped atheromata.
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Methods and Results—Intravascular ultrasound–based, geometrically correct 3-dimensional reconstruction of the coronary arteries of 12 swine was performed in vivo 23 weeks after initiation of diabetes mellitus and a hyperlipidemic diet. Local endothelial shear stress was calculated in plaque-free subsegments of interest (n=142) with computational fluid dynamics. At week 30, the coronary arteries (n=31) were harvested and the same subsegments were identified. The messenger RNA and protein expression and elastolytic activity of selected elastases and their endogenous inhibitors were assessed. Subsegments with low preceding endothelial shear stress at week 23 showed reduced endothelial coverage, enhanced lipid accumulation, and intense infiltration of activated inflammatory cells at week 30. These lesions showed increased expression of messenger RNAs encoding matrix metalloproteinase-2, -9, and -12, and cathepsins K and S relative to their endogenous inhibitors and increased elastolytic activity. Expression of these enzymes correlated positively with the severity of internal elastic lamina fragmentation. Thin-capped atheromata developed in regions with lower preceding endothelial shear stress and had reduced endothelial coverage, intense lipid and inflammatory cell accumulation, enhanced messenger RNA expression and elastolytic activity of MMPs and cathepsins, and severe internal elastic lamina fragmentation.
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Conclusions—Low endothelial shear stress induces endothelial discontinuity and accumulation of activated inflammatory cells, thereby augmenting the expression and activity of elastases in the intima and shifting the balance with their inhibitors toward matrix breakdown. Our results provide new insight into the mechanisms of regional formation of plaques with thin fibrous caps.Novartis Pharmaceuticals CorporationBoston Scientific CorporationHellenic Heart FoundationHellenic Atherosclerosis SocietyAlexander S. Onassis Public Benefit FoundationPropondis FoundationHellenic Harvard FoundationA.G. Leventis FoundationPhilip Morris International. External Research ProgramAmerican Heart Association (Scientist Development Grant)National Institutes of Health (U.S.) (Grant NIHR01 GM49039
The Inverse Conjecture for the Gowers Norm is False
No full textLet p be a fixed prime number, and N be a large integer. The ’Inverse Conjecture for the Gowers norm ’ states that if the ”d-th Gowers norm ” of a function f: FN p → F is non-negligible, that is larger than a constant independent of N, then f can be non-trivially approximated by a degree d − 1 polynomial. The conjecture is known to hold for d = 2, 3 and for any prime p. In this paper we show the conjecture to be false for p = 2 and for d = 4, by presenting an explicit function whose 4-th Gowers norm is non-negligible, but whose correlation any polynomial of degree 3 is exponentially small. Essentially the same result (with different correlation bounds) was independently obtained by Green and Tao [5]. Their analysis uses a modification of a Ramsey-type argument of Alon and Beigel [1] to show inapproximability of certain functions by low-degree polynomials. We observe that a combination of our results with the argument of Alon and Beigel implies the inverse conjecture to be false for any prime p, for d = p2.
An Unusual Case of Saline Contrast Injected in the Anterior Cubital Vein Appearing in the Left Heart Prior to the Right Heart
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