309 research outputs found

    Partially Walking a Polygon

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    Deciding two-guard walkability of an n-sided polygon is a well-understood problem. We study the following more general question: How far can two guards reach from a given source vertex while staying mutually visible, in the (more realistic) case that the polygon is not entirely walkable? There can be Theta(n) such maximal walks, and we show how to find all of them in O(n log n) time

    Односторонний и двусторонний эффект памяти формы в [([3)12]]-монокристаллах сплава Ni[49]Fe[18]Ga[27]Co[6]

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    This study was performed to assess the role of additional myocardial perfusion imaging during high dose dobutamine/atropine stress magnetic resonance (DSMR-wall motion) for the evaluation of patients with intermediate (50-70%) coronary artery stenosis. Routine DSMR-wall motion was combined with perfusion imaging (DSMR-perfusion) in 174 consecutive patients with chest pain syndromes who were scheduled for a clinically indicated coronary angiography. When defining CAD as the presence of a ≥ 50% stenosis, the addition of perfusion imaging improved sensitivity (90 vs. 79%, P < 0.001) with a non-significant reduction in specificity (85 vs. 90%, P = 0.13) and an improvement in overall diagnostic accuracy (88 vs. 84%, P = 0.008). Adding perfusion imaging improved sensitivity in patients with intermediate stenosis (87 vs. 72%, P = 0.03), but not in patients with severe (≥70%) stenosis (93 vs. 84%, P = 0.06). In patients with severe stenosis specificity of DSMR-perfusion versus DSMR-wall motion decreased (61 vs 70%, P = 0.001) resulting in a lower overall accuracy (71 vs 74%, P = 0.03). Using a cutoff of ≥50% for the definition of CAD, sensitivity of DSMR-perfusion compared to DSMR-wall motion was significantly higher in patients with single vessel (88 vs. 77%, P = 0.03) and multi vessel disease (93 vs. 79%, P = 0.03), whereas no significant differences were found using a cutoff of ≥70% stenosis for the definition of CAD. The addition of perfusion imaging during DSMR-wall motion improved the sensitivity in patients with intermediate coronary artery stenosis. Overall diagnostic accuracy increased only when defining CAD as ≥50% stenosis. In patients with ≥70% stenosis DSMR-wall motion alone had higher accuracy due to more false-positive cases with DSMR-perfusion

    Insulin resistance and glycemic abnormalities are associated with deterioration of left ventricular diastolic function: a cross-sectional study

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    <p>Abstract</p> <p>Background</p> <p>Left ventricular diastolic dysfunction (LVDD) is considered a precursor of diabetic cardiomyopathy, while insulin resistance (IR) is a precursor of type 2 diabetes mellitus (T2DM) and independently predicts heart failure (HF). We assessed whether IR and abnormalities of the glucose metabolism are related to LVDD.</p> <p>Methods</p> <p>We included 208 patients with normal ejection fraction, 57 (27%) of whom had T2DM before inclusion. In subjects without T2DM, an oral glucose tolerance test (oGTT) was performed. IR was assessed using the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR). The lower limit of the top quartile of the HOMA-IR distribution (3.217) was chosen as threshold for IR. LVDD was verified according to current guidelines.</p> <p>Results</p> <p>IR was diagnosed in 38 (18%) patients without a history of diabetes. The prevalence of LVDD was 92% in subjects with IR vs. 72% in patients without IR (n = 113), respectively (p = 0.013). In the IR group, the early diastolic mitral inflow velocity (E) in relation to the early diastolic tissue Doppler velocity (averaged from the septal and lateral mitral annulus, E'av) ratio (E/E'av) was significantly higher compared to those without IR (9.8 [8.3-11.5] vs. 8.1 [6.6-11.0], p = 0.011). This finding remains significant when patients with IR and concomitant T2DM based on oGTT results were excluded (E/E'av ratio 9.8 [8.2-11.1)] in IR vs. 7.9 [6.5-10.5] in those without both IR and T2DM, p = 0.014). There were significant differences among patients with and without LVDD regarding the HOMA-IR (1.71 [1.04-3.88] vs. 1.09 [0.43-2.2], p = 0.003). The HOMA-IR was independently associated with LVDD on multivariate logistic regression analysis, a 1-unit increase in HOMA-IR value was associated with an odds ratio for prevalent LVDD of 2.1 (95% CI 1.3-3.1, p = 0.001). Furthermore, the E/E'av ratio increases along the glucose metabolism status from normal glucose metabolism (7.6 [6.2-10.1]) to impaired glucose tolerance (8.8 [7.4-11.0]) and T2DM (10.5 [8.1-13.2]), respectively (p < 0.001).</p> <p>Conclusions</p> <p>Insulin resistance is independently associated with LVDD in subjects without overt T2DM. Patients with IR and glucose metabolism disorders might represent a target population to prevent the development of HF. Screening programs for glucose metabolism disturbances should address the assessment of diastolic function and probably IR.</p

    Misericordia regia, es decir, negociemos. Alfonso VII y los Lara en la 'Chronica Adefonsi imperatoris'

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    [ES] Los discursos surgidos por inspiración -cuando no directa agencia- del poder regio son hegemónicos entre las fuentes narrativas del medievo castellano-leonés. Quizás por ello, suelen abundar en estos textos visiones de las relaciones entre monarquía y nobleza concebidas como polos opuestos en una dinámica recurrente de enfrentamiento-consenso: la monarquía aglutinadora de las aspiraciones colectivas de una comunidad, frente a unos nobles egoístas por naturaleza, que depredan los recursos de aquélla en beneficio propio, y que deben ser canalizados hacia el servicio al bien común. Lejos de limitarse a la época medieval, esta forma de entender las dinámicas políticas medievales constituye una tradición vetusta, originada en el propio medievo, reiterada hasta la saciedad en la época moderna, y que goza aún hoy de buena salud y sigue produciendo retoños de manera continuada, con toda su carga legitimadora de la genealogía del poder del presente. En este trabajo se analiza un ejemplo concreto del siglo XII -el conflicto entre Alfonso VII y los Lara- para mostrar como la retórica del perdón/castigo regios puede estar ocultando la necesidad práctica de negociar las relaciones de fuerza entre Monarquía y Nobleza.Peer reviewe

    Safe procedures despite ultra low radiation doses during catheter ablations of atrial and ventricular arrhythmias—A multicenter experience

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    Introduction: Despite the development of non-fluoroscopic catheter visualization options, fluoroscopy is still used in most ablation procedures. The aim of this multicenter study was to evaluate the safety and efficacy of a new ultra-low dose radiation protocol for EP procedures in a large number of patients. Methods and results: A total of 3462 consecutive patients (male 1926 (55.6%), age 64.4 ± 14.0 years, BMI 26.65 ± 4.70) undergoing radiofrequency ablation (left atrial (n = 2316 [66.9%], right atrial (n = 675 [19.5%], or ventricular (n = 471 [13.6%]) in three German centers were included in the analysis. Procedures were performed using a new ultra-low dose protocol operating at 8nGy for fluoroscopy and 36nGy for cine-loops. Additionally a very low framerate (2-3FPS) was used. Using the new protocol very low Air kerma-area product (KAP) values were achieved for left atrial ablations (104.25 ± 84.22 μGym2 ), right atrial ablations (70.98 ± 94.79 μGym2 ) and ablations for ventricular tachycardias or PVCs (78.62 ± 66.59 μGym2 ). Acute procedural success was achieved in 3289/3388 (97.1%) while the rate of major complications was very low compared to previously published studies not using low dose settings (n = 20, 0.6%). Conclusion: The ultra-low dose, low framerate protocol leads to very low radiation doses for all EP procedures while neither procedural time, fluoroscopy time nor success or complication rates were compromised. When compared to current real-world Air KAP data the new ultra-low dose fluoroscopy protocol reduces radiation exposure by more than 90%

    2D Semiconductor Nonlinear Plasmonic Modulators

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    A plasmonic modulator is a device that controls the amplitude or phase of propagating plasmons. In a pure plasmonic modulator, the presence or absence of a pump plasmonic wave controls the amplitude of a probe plasmonic wave through a channel. This control has to be mediated by an interaction between disparate plasmonic waves, typically requiring the integration of a nonlinear material. In this work, we demonstrate the first 2D semiconductor nonlinear plasmonic modulator based on a WSe2 monolayer integrated on top of a lithographically defined metallic waveguide. We utilize the strong coupling between the surface plasmon polaritons, SPPs, and excitons in the WSe2 to give a 73 percent change in transmission through the device. We demonstrate control of the propagating SPPs using both optical and SPP pumps, realizing the first demonstration of a 2D semiconductor nonlinear plasmonic modulator, with a modulation depth of 4.1 percent, and an ultralow switching energy estimated to be 40 aJ

    Genetic Variation in ABCC4 and CFTR and Acute Pancreatitis during Treatment of Pediatric Acute Lymphoblastic Leukemia

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    Background: Acute pancreatitis (AP) is a serious, mechanistically not entirely resolved side effect of L-asparaginase-containing treatment for acute lymphoblastic leukemia (ALL). To find new candidate variations for AP, we conducted a genome-wide association study (GWAS). Methods: In all, 1,004,623 single-nucleotide variants (SNVs) were analyzed in 51 pediatric ALL patients with AP (cases) and 1388 patients without AP (controls). Replication used independent patients. Results: The top-ranked SNV (rs4148513) was located within the ABCC4 gene (odds ratio (OR) 84.1; p = 1.04 × 10−14). Independent replication of our 20 top SNVs was not supportive of initial results, partly because rare variants were neither present in cases nor present in controls. However, results of combined analysis (GWAS and replication cohorts) remained significant (e.g., rs4148513; OR = 47.2; p = 7.31 × 10−9). Subsequently, we sequenced the entire ABCC4 gene and its close relative, the cystic fibrosis associated CFTR gene, a strong AP candidate gene, in 48 cases and 47 controls. Six AP-associated variants in ABCC4 and one variant in CFTR were detected. Replication confirmed the six ABCC4 variants but not the CFTR variant. Conclusions: Genetic variation within the ABCC4 gene was associated with AP during the treatment of ALL. No association of AP with CFTR was observed. Larger international studies are necessary to more conclusively assess the risk of rare clinical phenotypes

    Using RNA secondary structures to guide sequence motif finding towards single-stranded regions

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    RNA binding proteins recognize RNA targets in a sequence specific manner. Apart from the sequence, the secondary structure context of the binding site also affects the binding affinity. Binding sites are often located in single-stranded RNA regions and it was shown that the sequestration of a binding motif in a double-strand abolishes protein binding. Thus, it is desirable to include knowledge about RNA secondary structures when searching for the binding motif of a protein. We present the approach MEMERIS for searching sequence motifs in a set of RNA sequences and simultaneously integrating information about secondary structures. To abstract from specific structural elements, we precompute position-specific values measuring the single-strandedness of all substrings of an RNA sequence. These values are used as prior knowledge about the motif starts to guide the motif search. Extensive tests with artificial and biological data demonstrate that MEMERIS is able to identify motifs in single-stranded regions even if a stronger motif located in double-strand parts exists. The discovered motif occurrences in biological datasets mostly coincide with known protein-binding sites. This algorithm can be used for finding the binding motif of single-stranded RNA-binding proteins in SELEX or other biological sequence data

    HIV-1 suppression and durable control by combining single broadly neutralizing antibodies and antiretroviral drugs in humanized mice

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    Effective control of HIV-1 infection in humans is achieved using combinations of antiretroviral therapy (ART) drugs. In humanized mice (hu-mice), control of viremia can be achieved using either ART or by immunotherapy using combinations of broadly neutralizing antibodies (bNAbs). Here we show that treatment of HIV-1–infected hu-mice with a combination of three highly potent bNAbs not only resulted in complete viremic control but also led to a reduction in cell-associated HIV-1 DNA. Moreover, lowering the initial viral load by coadministration of ART and immunotherapy enabled prolonged viremic control by a single bNAb after ART was withdrawn. Similarly, a single injection of adeno-associated virus directing expression of one bNAb produced durable viremic control after ART was terminated. We conclude that immunotherapy reduces plasma viral load and cell-associated HIV-1 DNA and that decreasing the initial viral load enables single bNAbs to control viremia in hu-mice
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