1,398 research outputs found

    Localization Transition in Incommensurate non-Hermitian Systems

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    A class of one-dimensional lattice models with incommensurate complex potential V(θ)=2[λrcos(θ)+iλisin(θ)]V(\theta)=2[\lambda_r cos(\theta)+i \lambda_i sin(\theta)] is found to exhibit localization transition at λr+λi=1|\lambda_r|+|\lambda_i|=1. This transition from extended to localized states manifests in the behavior of the complex eigenspectum. In the extended phase, states with real eigenenergies have finite measure and this measure goes to zero in the localized phase. Furthermore, all extended states exhibit real spectrum provided λrλi|\lambda_r| \ge |\lambda_i|. Another novel feature of the system is the fact that the imaginary part of the spectrum is sensitive to the boundary conditions {\it only at the onset to localization}

    EVALUATION OF AN EXPERIMENTAL SCREW-RETAINED RETRIEVABLE CROWN VERSUS CONVENTIONAL CROWN DESIGN

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    Statement of problem: Removing cemented crowns is usually a complicated procedure that may lead to irreversible damage to the tooth/crown and mostly necessitate remake of crown with added effort for both patient and clinician. Purpose: This in-vitro study evaluated an experimental two-component, screw-retained retrievable crown design in comparison to the conventional design. Materials and methods: A total of 120 extracted maxillary 2nd premolars received root canal treatment and were divided into two groups (n=60 each) according to the crown design they will receive. Gp CC received a threaded modified post, a composite core and a metal coping, while Gp RC received a two-component retrievable crown design. Fracture resistance was assessed by a 90 degrees vertical load to the center of the occlusal surface, using universal testing machine, under a constant crosshead speed of 0.5 mm/min until failure. Microleakage was assessed by placing specimens in methylene blue dye for 12 hours, sectioning the teeth longitudinally, and then examining the sectioned samples under stereomicroscope. Retrievability testing was conducted by 5 prosthodontists who attempted to uncover and unscrew the posts. Data were statistically evaluated using computer software (SPSS version 17; SPSS Inc.). Results: No significant difference between the 2 designs tested regarding microleakage tests (P=.34) whereas the experimental design, was significantly more resistant to fracture and more retrievable than the conventional one (P\u3e.5). Conclusions: The proposed retrievable crown design showed promising results and may be considered as an option to substitute the conventional design. Further studies are needed to confirm that

    Can lung volumes and capacities be used as an outcome measure for phrenic nerve recovery after cardiac surgeries?

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    AbstractPhrenic nerve is the main nerve drive to the diaphragm and its injury is a well-known complication following cardiac surgeries. It results in diaphragmatic dysfunction with reduction in lung volumes and capacities. This study aimed to evaluate the objectivity of lung volumes and capacities as an outcome measure for the prognosis of phrenic nerve recovery after cardiac surgeries. In this prospective experimental study, patients were recruited from Cardio-Thoracic Surgery Department, Educational-Hospital of College of Medicine, Cairo University. They were 11 patients with right phrenic nerve injury and 14 patients with left injury. On the basis of receiving low-level laser irradiation, they were divided into irradiated group and non-irradiated group. Measures of phrenic nerve latency, lung volumes and capacities were taken pre and post-operative and at 3-months follow up. After 3months of low-level laser therapy, the irradiated group showed marked improvement in the phrenic nerve recovery. On the other hand, vital capacity and forced expiratory volume in the first second were the only lung capacity and volume that showed improvement consequent with the recovery of right phrenic nerve (P value <0.001 for both). Furthermore, forced vital capacity was the single lung capacity that showed significant statistical improvement in patients with recovered left phrenic nerve injury (P value <0.001). Study concluded that lung volumes and capacities cannot be used as an objective outcome measure for recovery of phrenic nerve injury after cardiac surgeries

    Predicting breast screening attendance using machine learning techniques

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    Coffee Grounds as a Soil Conditioner: Effects on Physical and Mechanical Properties - I. Effects on Physical Properties

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    Coffee grounds (CG) improved some soil physical properties (dry density, gd; porosity, n; aggregation; hydraulic conductivity, Ks; and infiltration rate, IR). Effects on other properties were inconsistent (e.g., sorptivity, S), or unfavorable (e.g., available water, AW). gd decreased and n increased with CG. CG decreased Ks in sand. In calcareous soil, maximum increase was associated with 10% and 15% CG before and after wetting-and-drying cycles (WDC), respectively. Ks increased with CG in clay, with greatest increase attained at 10% CG. IR decreased with CG in sand. In calcareous and clayey soils, IR decreased with CG before WDC but increased after WDC where maximum increase in clay was linked to 10% CG. No solid trends of soil sorptivity, S, were identified. Before WDC, S had the order: sand &gt; calcareous &gt; clay. For most cases, adding CG increased total water holding capacity (WHC). However, after WDC, the increase in water content at field capacity (FC) with CG was accompanied by a greater increase in wilting point (WP) and therefore a decrease in AW. CG improved soil structure and aggregation and increased non-water-stable aggregates in calcareous and clayey soils. Mean weight diameter (MWD) indicated increase in water-stable aggregates in sand at 5% and 10% CG. In clay, MWD increased only at 5% CG. Although results did not show coherent responses with some tested properties, they, mostly, indicate some beneficial effects of CG, particularly in relation to improving aggregation and water flow

    A large-scale proteogenomics study of apicomplexan pathogens-Toxoplasma gondii and Neospora caninum

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    Proteomics data can supplement genome annotation efforts, for example being used to confirm gene models or correct gene annotation errors. Here, we present a large‐scale proteogenomics study of two important apicomplexan pathogens: Toxoplasma gondii and Neospora caninum. We queried proteomics data against a panel of official and alternate gene models generated directly from RNASeq data, using several newly generated and some previously published MS datasets for this meta‐analysis. We identified a total of 201 996 and 39 953 peptide‐spectrum matches for T. gondii and N. caninum, respectively, at a 1% peptide FDR threshold. This equated to the identification of 30 494 distinct peptide sequences and 2921 proteins (matches to official gene models) for T. gondii, and 8911 peptides/1273 proteins for N. caninum following stringent protein‐level thresholding. We have also identified 289 and 140 loci for T. gondii and N. caninum, respectively, which mapped to RNA‐Seq‐derived gene models used in our analysis and apparently absent from the official annotation (release 10 from EuPathDB) of these species. We present several examples in our study where the RNA‐Seq evidence can help in correction of the current gene model and can help in discovery of potential new genes

    Coffee grounds as a soil conditioner: Effects on physical and mechanical properties – II. Effects on mechanical properties

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    Applying coffee grounds (CG) to sandy, calcareous, and clayey soils resulted in notable effects on soil expansion, cracking, cohesion, internal friction, initial stress and resistance to penetration. In sand, expansion upon saturation was greater after wetting-and-drying cycles. Highest increases were 15.71%, 16.14% and 31.86% for sandy, calcareous and clayey soils, respectively. Effect of CG on cracking was negligible in sand and very slight (&lt;1.0%) in the calcareous soil but marked in clay (14.18% at 10% CG). In sand, cohesion (c) increased significantly with CG up to the 10% content. Cohesion increased by 2.5-folds and 4.5-folds at 5% and 10% CG, respectively. The presence of fine CG grains among larger sand particles, boosted microbial activities, and the resulting cementing and binding effects resulted in increased cohesion. For calcareous soil, cohesion rose from 0.04 kg∙cm-2 to 0.13 kg∙cm-2 as CG increased from 0% to 15%. In clay, maximum cohesion (0.20 kg∙cm-2) was associated with the 10% CG and was highest of all soils. In sand, the angle of internal friction (φ) decreased notably as CG increased from 5% to 10% but there was no consistent pattern in any of the soils. An increase in initial stress (pi) was observed between 0% and 10% CG in sand and between 0% and 15% in calcareous soil while clay showed no particular trend. Patterns of pi were, thus, consistent with those of cohesion for all soils. Resistance to penetration increased substantially with CG in sand. The effect in calcareous and clayey soils took an opposite trend to that of sand and resistance was generally higher in calcareous soil. Overall effects of CG on resistance were desirable in all soils as far as agriculture (seedling emergence, crop growth, irrigation, etc.) is concerned

    Pancreatic pseudocyst eroding into the splenoportal venous confluence and mimicking an arterial aneurysm

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    We report the case of a 62-year-old man with chronic pancreatitis who presented with increasing abdominal pain. Sonography, magnetic resonance imaging, contrast-enhanced computed tomography, and ultimately catheter angiography demonstrated a pancreatic pseudocyst that had eroded into the splenoportal venous confluence, mimicking an arterial aneurysm. The diagnostic was confirmed at the time of surgical treatment. This case demonstrates the use of imaging to diagnose complications of pancreatitis, and the difficulty of distinguishing an eroding pseudocyst from an arterial aneurysm
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