31 research outputs found
Parameterized Complexity of Two-Interval Pattern Problem
A 2-interval is the union of two disjoint intervals on the real line. Two 2-intervals D? and D? are disjoint if their intersection is empty (i.e., no interval of D? intersects any interval of D?). There can be three different relations between two disjoint 2-intervals; namely, preceding (<), nested (?) and crossing (?). Two 2-intervals D? and D? are called R-comparable for some R?{<,?,?}, if either D?RD? or D?RD?. A set ? of disjoint 2-intervals is ?-comparable, for some ??{<,?,?} and ???, if every pair of 2-intervals in ? are R-comparable for some R??. Given a set of 2-intervals and some ??{<,?,?}, the objective of the {2-interval pattern problem} is to find a largest subset of 2-intervals that is ?-comparable.
The 2-interval pattern problem is known to be W[1]-hard when |?|=3 and NP-hard when |?|=2 (except for ?={<,?}, which is solvable in quadratic time). In this paper, we fully settle the parameterized complexity of the problem by showing that it is W[1]-hard for both ?={?,?} and ?={<,?} (when parameterized by the size of an optimal solution). This answers the open question posed by Vialette [Encyclopedia of Algorithms, 2008]
Boundary Labeling for Rectangular Diagrams
Given a set of n points (sites) inside a rectangle R and n points (label locations or ports) on its boundary, a boundary labeling problem seeks ways of connecting every site to a distinct port while achieving different labeling aesthetics. We examine the scenario when the connecting lines (leaders) are drawn as axis-aligned polylines with few bends, every leader lies strictly inside R, no two leaders cross, and the sum of the lengths of all the leaders is minimized. In a k-sided boundary labeling problem, where 1 <= k <= 4, the label locations are located on the k consecutive sides of R.
In this paper we develop an O(n^3 log n)-time algorithm for 2-sided boundary labeling, where the leaders are restricted to have one bend. This improves the previously best known O(n^8 log n)-time algorithm of Kindermann et al. (Algorithmica, 76(1):225-258, 2016). We show the problem is polynomial-time solvable in more general settings such as when the ports are located on more than two sides of R, in the presence of obstacles, and even when the objective is to minimize the total number of bends. Our results improve the previous algorithms on boundary labeling with obstacles, as well as provide the first polynomial-time algorithms for minimizing the total leader length and number of bends for 3- and 4-sided boundary labeling. These results settle a number of open questions on the boundary labeling problems (Wolff, Handbook of Graph Drawing, Chapter 23, Table 23.1, 2014)
Cluster endophthalmitis following multiple intravitreal bevacizumab injections from a single use vial
The risk of endophthalmitis is always a concern when an intraocular procedure is performed. Intravitreal injection is a frequently used method for therapeutic management of many diseases, affecting the posterior segment of the eye. Hence, it is important to assess the risk of complications, especially endophthalmitis. Most studies conducted concentrate on risk assessment from single use from single drug vial. The present article reports the occurrence of cluster endophthalmitis following multiple intravitreal bevacizumab injections from a single vial. Intravitreal injection of bevacizumab was administered to eight eyes of eight patients. Administered dose was prepared from single 4-ml vial of bevacizumab and was injected in the eye, after patient preparation and under aseptic conditions. The procedure was repeated for the remaining patients, thereby imparting multiple pricks in the same vial. Four of the eight patients reported to the hospital on the 3rd day after injection with complaints of pain, watering, and diminution of vision. Two patients reported the following day with similar complaints. Two patients who did not report by the 4th day were contacted and recalled for an examination. All the patients were thoroughly examined using slit lamp biomicroscopy and indirect ophthalmoscopy. Six out of eight were clinically diagnosed to have endophthalmitis and were administered intravitreal antibiotics. The present report highlights possibility of microbial contamination of the drug vial or during compounding process. However, from the present incident, we are encouraged to stay vigilant and wary of contaminatio
Modelling of flow behaviour in a LD vessel by an impinging gas jet
Present study is focused towards development of computational fluid dynamic model of oxygen impingement in the melt pool in case of LD (basic oxygen converter) steelmaking process. 1/30th scaled down model of the 100 ton LD converter has been developed and flow simulation has been performed based on volume of fluid technique, using Fluent as solver engine. Simulation of the steel bath and oxygen is carried out by using water and air, respectively. Effect of process variables on the LD steelmaking practice has been studied and the findings ascertain penetration depth of the oxygen jet into the liquid (metal) pool as a strong function of bath (lance) height, gas flow rate and nozzle exit diameter. Furthermore, an equation is developed by carrying out regression analysis using results obtained from numerical simulation. The study also provides insight into the surface deformation modes, their onsets and transition regimes, which originates due to the gas impingement into the melt pool. Finally, the computed results are compared with the experimental findings for selected cases and good agreement has been found
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Not AvailableSevere Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the cause of Coronavirus Disease (COVID-19) that has resulted in a global pandemic. At the time of writing, approximately 16.06 million cases have been reported worldwide. Like other coronaviruses, SARS-CoV-2 relies on the surface Spike glycoprotein to access the host cells, mainly through the interaction of its Receptor Binding Domain (RBD) with the host receptor Angiotensin-Converting Enzyme2 (ACE2). SARS-CoV-2 infection induces a profound downstream pro-inflammatory cytokine storm. This release of the pro-inflammatory cytokines is underpinning lung tissue damage, respiratory failure, and eventually multiple organ failure in COVID-19 patients. The phosphorylation status of ERK1/2 is positively correlated with virus load and ERK1/2 inhibition suppressed viral replication and viral infectivity. Therefore, molecular entities able to interfere with binding of the SARS-CoV-2 Spike protein to ACE2, or damping hyperinflammatory cytokines storm, blocking ERK1/2 phosphorylation have a great potential to inhibit viral entry along with viral infectivity. Herein, we report that the FDA-approved non-peptide opioid antagonist drug, naltrexone suppresses high fat/LPS induced pro-inflammatory cytokine release both from macrophage cells and Adipose Tissue Macrophage. Moreover, Low Dose Naltrexone (LDN) also showed its activity as an ERK1/2 inhibitor. Notably, virtual docking and simulation data also suggest LDN may disrupt the interaction of ACE2 with RBD. LDN may be considered as a target as the treatment and (or) adjuvant therapy for coronavirus infection. Clinical toxicity measurements may not be required for LDN since naltrexone was previously tested and is an approved drug by the FDA.Not Availabl