86,959 research outputs found
Random parallel algorithms for finding exact branchings, perfect matchings, and cycles
No full textIn this paper we devise randomized parallel algorithms which given a unary weighted (di)graph G=(V, E)construct in time O(log2| V|) branchings, perfect matchings, and disjoint cycles of weight exactly k belonging to G. These problems have been studied by Papadimitriou and Yannakakis [PY1], by Barahona and Pulleyblank [BP], by Camerini et al [CGM], and by Mulmuley et al. [MVV]. Our algorithms improve previous solutions. Moreover, we give an NC2 algorithm for computing the absolute value of the pfaffian of a skew-symmetric matrix
Analisi dei consumi di due classi di medicinali biotecnologici (ESA e G-CSF) in cinque Paesi europei.
No full textThe expected benefits of biosimilar drugs (a lower price and a competition effect on originators' price) offer an opportunity to contain the rising trend of the hospital pharmaceutical expenditure. This paper reviews the characteristics of biotechnological products and their regulatory features with the aim to evaluate if and how biosimilars are substituting the originators in the respective markets. Specifically, the study is focused on the two biologics markets ESA and G-CSF, because of their utilization and growth rate. The observation area includes five European countries (France, Germany, Italy, Spain, and UK) and the observation period encompasses the early years of the ESA/G-CSF biosimilars marketing in such area (2008-2011). Analytical sales data at package level were collected and converted to IU (ESA) or mcg (G-CSF). While the ESA total market (originators + biosimilars) did decline during the period and in the whole area under investigation (173 billion IUs in 2008 vs 158.1 billion in 2011), the biosimilars market alone soared (from 3.1 billion IUs in 2008 to 14.7 billion in 2011). So, a substitution effect did effectively occur, even if modest in relative terms (the biosimilars share of the total ESA market was only 8.5% in 2011). With reference to ESA biosimilars, the highest growth rate was in Italy and the largest market was in Germany. The overall G-CSF market grew from 2.7 million mcgs in 2008 to 3.4 million in 2011. However, biosimilars alone grew at a much higher speed (from 2.5 thousand mcgs to 432.3 thousand), implying a substitution effect similar to ESA's. G-CSF biosimilars market share in Italy ranked second in the five countries area. The substitution process of originators by biosimilars (at least in the markets, period and area observed in this study) appears relatively slow, mainly because of clinical reasons (only similarity, not therapeutic equivalence with originators, is acknowledged to biosimilars). However, the favorable impact of biosimilars on prices of, and expenditure for, biologic drugs cannot be denied. © 2013 Springer International Publishing Switzerland
On the difficulty of finding walks of length k
No full textWe characterize the computational complexity of the following combinatorial problem: Given a directed graph G = (V, E) endowed with a length function w : E ⇀ N, a pair of nodes s and t in V and an integer k ≥ 0, does G contain a walk π from s to t of length exactly k? We show that the problem is NP-complete when G is a directed graph, an undirected graph, or a directed acyclic graph. The problem becomes NL-complete when w is a unary function
Silverskin: from waste to a renewable source of bioactive compounds
No full textSilverskin is the thin layer covering the coffee beans. During the roasting coffee process, it is removed becoming a by-product. The large production (150.000 t/year on global scale, of which 7.500 t/years in Italy) of this waste calls for its re-functionalization in order to reduce the impact of industrial by-products in the environment. Currently the only use of coffee silverskin (CS) is as renewable energy source or as fertilizer (1,2), no other utilization has been developed for CS so far. Despite this, the chemical composition of CS indicates the presence of interesting bioactive molecules (i.e. lipids, chlorogenics acids, caffeine) that confer to this by-product antioxidant and prebiotic properties. (3)This evidence suggests its re-use as well in other industrial fields such as nutraceutical, cosmetic and pharmaceutical as aimed by CirCO project. In this hypothesis of revalorization, it cannot be excluded the potential use of CS lipid matter in cosmetic formulations or as additive for the technology of paper processing (4). For the isolation of CS oil, supercritical CO2 was selected as more sustainable separation technique, alternative to classical solvent extraction processes.(5) We observed that an appropriate modulation of process parameters (T, P) influence the oil rate and the chemical composition opening the way for targeted extraction. In details the application of mild conditions (35°C, 100/200psi) led to majority extraction of palmitic (C16:0) and linoleic (C18:2) acids with an overall yield of 1.9% (goil/100gCS). The increase of pressure (100 bar300 bar) and temperature (35°C60°C) promoted the extraction of arachidic acid (C20:0), behenic acid (C22:0) and lignoceric acid (C24:0) with a calculated oil yield of 3.3% (goil/100gCS). The best identified conditions were employed for the industrial scale-up giving results comparable to laboratory scale. For a possible commercial process application, it is essential to test the applicability of appropriate models for SFE of lipids from oil-containing substrates.(5) For this purpose a mathematical model is constructed based on the experimental data collected, employed apparatus and chemical-physical characteristic of biomass in tightly collaboration with prof. Manenti at Politecnico of Milan
Supported copper precatalysts for ligand-free, palladium-free Sonogashira coupling reactions
No full textCopper(II) oxide and Cu metal, highly dispersed on inert oxides ( silica, alumina), have been employed as precatalysts in ligand-free, palladium-free Sonogashira coupling reactions. Best results were obtained with highly dispersed Cu metal on alumina, which exhibited high reactivity with aryl iodides. Electron-rich alkynes, in particular arylacetylenes, act as the most effective alkyne substrates. The present catalytic system appears attractive in view of its ease of application and low cost, due to the use of a readily available non-noble metal catalyst combined with the absence of ligands
Pharmacokinetic and pharmacodynamic (PK/PD) evaluation of cefazolin in dog
No full textThe objectives of this study were to investigate the pharmacokinetics of danofloxacin and its metabolite N-desmethyldanofloxacin and to determine their concentrations in synovial fluid after administration by the intravenous, intramuscular or intragastric routes. Six adult mares received danofloxacin mesylate administered intravenously (i.v.) or intramuscularly (i.m.) at a dose of 5 mg/kg, or intragastrically (IG) at a dose of 7.5 mg/kg using a randomized Latin square design. Concentrations of danofloxacin and N-desmethyldanofloxacin were measured by UPLC-MS/MS. After i.v. administration, danofloxacin had an apparent volume of distribution (mean ± SD) of 3.57 ± 0.26 L/kg, a systemic clearance of 357.6 ± 61.0 mL/h/kg, and an elimination half-life of 8.00 ± 0.48 h. Maximum plasma concentration (Cmax) of N-desmethyldanofloxacin (0.151 ± 0.038 μg/mL) was achieved within 5 min of i.v. administration. Peak danofloxacin concentrations were significantly higher after i.m. (1.37 ± 0.13 μg/mL) than after IG administration (0.99 ± 0.1 μg/mL). Bioavailability was significantly higher after i.m. (100.0 ± 12.5%) than after IG (35.8 ± 8.5%) administration. Concentrations of danofloxacin in synovial fluid samples collected 1.5 h after administration were significantly higher after i.v. (1.02 ± 0.50 μg/mL) and i.m. (0.70 ± 0.35 μg/mL) than after IG (0.20 ± 0.12 μg/mL) administration. Monte Carlo simulations indicated that danofloxacin would be predicted to be effective against bacteria with a minimum inhibitory concentration (MIC) ≤0.25 μg/mL for i.v. and i.m. administration and 0.12 μg/mL for oral administration to maintain an area under the curve:MIC ratio ≥50
A plant for the treatment of biological sludges with recovery of secondary raw materials and energy
No full textHeterogeneous selective catalytic hydrogenation of aryl ketones to alcohols without additives
No full textA selective hydrogenation of different aryl ketones can be obtained by using a heterogeneous copper catalyst under very mild experimental conditions, namely 90 C and 1 atm of hydrogen, without using any kind of additive or poisoning agent. © 2005 Elsevier Ltd. All rights reserved
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