An efficient decomposition approach for surgical planning

This talk presents an efficient decomposition approach to surgical planning. Given a set of surgical waiting lists (one for each discipline) and an operating theater, the problem is to decide the room-to-discipline assignment for the next planning period (Master Surgical Schedule), and the surgical cases to be performed (Surgical Case Assignment), with the objective of optimizing a score related to priority and current waiting time of the cases. While in general MSS and SCA may be concurrently found by solving a complex integer programming problem, we propose an effective decomposition algorithm which does not require expensive or sophisticated computational resources, and is therefore suitable for implementation in any real-life setting. Our decomposition approach consists in first producing a number of subsets of surgical cases for each discipline (potential OR sessions), and select a subset of them. The surgical cases in the selected potential sessions are then discarded, and only the structure of the MSS is retained. A detailed surgical case assignment is then devised filling the MSS obtained with cases from the waiting lists, via an exact optimization model. The quality of the plan obtained is assessed by comparing it with the plan obtained by solving the exact integrated formulation for MSS and SCA. Nine different scenarios are considered, for various operating theater sizes and management policies. The results on instances concerning a medium-size hospital show that the decomposition method produces comparable solutions with the exact method in much smaller computation time

Have Cherenkov telescopes detected a new light boson?

Recent observations by H.E.S.S. and MAGIC strongly suggest that the Universe is more transparent to very-high-energy gamma rays than previously thought. We show that this fact can be reconciled with standard blazar emission models provided that photon oscillations into a very light Axion-Like Particle occur in extragalactic magnetic fields. A quantitative estimate of this effect indeed explains the observed data and in particular the spectrum of blazar 3C279.Comment: 3 pages, 1 figure, Proceeding of the "Eleventh International Workshop on Topics in Astroparticle and Underground Physics" (TAUP), Roma, Italy, 1 - 5 July 2009 (to be published in the Proceedings

Electron Positron Annihilation Radiation from SgrA East at the Galactic Center

Maps of the Galactic electron-positron annihilation radiation show evidence for three distinct and significant features: (1) a central bulge source, (2) emission in the Galactic plane, and (3) an enhancement of emission at positive latitudes above the Galactic Center. In this paper, we explore the possibility that Sgr A East, a very prominent radio structure surrounding the Galactic nucleus, may be a significant contributer to the central bulge feature. The motivation for doing so stems from a recently proposed link between this radio object and the EGRET gamma-ray source 2EG J1746-2852. If this association is correct, then Sgr A East is also expected to be a source of copious positron production. The results presented here show that indeed Sgr A East must have produced a numerically significant population of positrons, but also that most of them have not yet had sufficient time to thermalize and annihilate. As such, Sgr A East by itself does not appear to be the dominant current source of annihilation radiation, but it will be when the positrons have cooled sufficiently and they have become thermalized. This raises the interesting possibility that the bulge component may be due to the relics of earlier explosive events like the one that produced Sgr A East.Comment: This manuscript was prepared with the AAS Latex macros v4.0 It is 37 pages long and has 16 figure

Treatment of Rheumatoid Arthritis-Associated Interstitial Lung Disease: Lights and Shadows

Rheumatoid arthritis (RA) is a chronic and systemic inflammatory disease affecting 0.5-1% of the population worldwide. Interstitial lung disease (ILD) is a serious pulmonary complication of RA and it is responsible for 10-20% of mortality, with a mean survival of 5-8 years. However, nowadays there are no therapeutic recommendations for the treatment of RA-ILD. Therapeutic options for RA-ILD are complicated by the possible pulmonary toxicity of many disease modifying anti-rheumatic drugs (DMARDs) and by their unclear efficacy on pulmonary disease. Therefore, joint and lung involvement should be evaluated independently of each other for treatment purposes. On the other hand, some similarities between RA-ILD and idiopathic pulmonary fibrosis and the results of the recent INBIULD trial suggest a possible future role for antifibrotic agents. From this perspective, we review the current literature describing the pulmonary effects of drugs (immunosuppressants, conventional, biological and target synthetic DMARDs and antifibrotic agents) in patients with RA and ILD. In addition, we suggest a framework for the management of RA-ILD patients and outline a research agenda to fill the gaps in knowledge about this challenging patient cohort

A new light boson from MAGIC observations?

Recent detection of blazar 3C279 by MAGIC has confirmed previous indications by H.E.S.S. that the Universe is more transparent to very-high-energy gamma rays than currently thought. This circumstance can be reconciled with observations of nearby blazars provided that photon oscillations into a very light Axion-Like Particle occur in extragalactic magnetic fields. The emerging "DARMA scenario" can be tested in the near future by the satellite-borne Fermi LAT detector as well as by the ground-based Imaging Atmospheric Cherenkov Telescopes H.E.S.S., MAGIC, CANGAROO III, VERITAS and by the Extensive Air Shower arrays ARGO-YBJ and MILAGRO.Comment: 4 pages, 1 figure, Proceeding of the "Neutrino Oscillation Workshop", Conca Specchiulla, Otranto, Italy, 6-12 September 200

Characterization of four novel bacteriophages targeting multi-drug resistant Klebsiella pneumoniae strains of sequence type 147 and 307

Introduction: the development of alternative antimicrobial strategies is deemed to be a high priority to deal with the challenge caused by the spread of multidrug-resistant (MDR) bacteria in clinical settings. according to several international organizations, phages or components thereof are one of these possible options that could be useful to treat bacterial infections. among the drug-resistant bacteria, carbapenem resistant Klebsiella pneumoniae (CR-Kp) are particularly worrisome, given the extensive MDR profiles, their pandemic dissemination and primary role in healthcare associated and life-threatening infections. In this study we isolated and characterised four lytic bacteriophages targeting two major high-risk clones of CR-Kp circulating in hospital environments, i.e., those belonging to Sequence Type (ST) 307 and ST147. Materials and methods: wastewater samples collected from hospitals located in central Italy were screened for the presence of phages by using a previously characterized collection of K. pneumoniae clinical isolates as hosts and the top-agar overlay technique. host specificity and infection efficiency was assessed by spot test and efficiency of plating, respectively. Dynamic of bacterial infections was determined by the one-step growth curve method. Phages were visualized through transmission electron microscopy (TEM) and their genomes were obtained and analysed by a Next Generation Sequencing approach followed by bioinformatics analysis. Results: four bacteriophages, named GP-1, GP-2, GP-4 and GP-5, have been isolated, purified and produced at high titres. collectively, two phages were able to selectively lyse 12/14 K. pneumoniae strains of ST307, while the other two were active only against all the tested K. pneumoniae strains of ST147 (n=12). phages maintain an overall good stability to temperature and pH changes and were characterized by infection cycles having latency periods ranging from 10 to 50 minutes and burst sizes of 10-100 PFU. results from TEM analysis and genome sequencing demonstrated that the four phages were of different families and allowed to rule out the presence of antibiotic resistance genes, virulence factors or toxins. Discussion and Conclusions: Considering their strictly lytic nature and their high selectivity towards two of the major high-risk clones of K. pneumoniae, the isolated phages can be considered as good candidates for their evaluation in animal models as members of cocktails for applications to treat severe infections caused by CR-Kp strains

A simple phenotypic method for screening of MCR-1-mediated colistin resistance

Objectives: To evaluate a novel method, the colistin-MAC test, for phenotypic screening of acquired colistin resistance mediated by transferable mcr-1 resistance determinants, based on colistin MIC reduction in the presence of dipicolinic acid (DPA). Methods: The colistin-MAC test consists in a broth microdilution method, in which colistin MIC is tested in the absence or presence of DPA (900 \u3bcg/mL). Overall, 74 colistin-resistant strains of Enterobacteriaceae (65 Escherichia coli and nine other species), including 61 strains carrying mcr-1-like genes and 13 strains negative for mcr genes, were evaluated with the colistin-MAC test. The presence of mcr-1-like and mcr-2-like genes was assessed by real-time PCR and end-point PCR. For 20 strains, whole-genome sequencing data were also available. Results: A 658-fold reduction of colistin MIC in the presence of DPA was observed with 59 mcr-1-positive strains, including 53 E. coli of clinical origin, three E. coli transconjugants carrying MCR-1-encoding plasmids, one Enterobacter cloacae complex and two Citrobacter spp. Colistin MICs were unchanged, increased or at most reduced by twofold with the 13 mcr-negative colistin-resistant strains (nine E. coli and four Klebsiella pneumoniae), but also with two mcr-1-like-positive K. pneumoniae strains. Conclusions: The colistin-MAC test could be a simple phenotypic test for presumptive identification of mcr-1-positive strains among isolates of colistin-resistant E. coli, based on a 658-fold reduction of colistin MIC in the presence of DPA. Evaluation of the test with a larger number of strains, species and mcr-type resistance determinants would be of interest

Multimodal Phase-Based X-Ray Microtomography with Nonmicrofocal Laboratory Sources

We present an alternative laboratory implementation of x-ray phase-contrast tomography through a beam-tracking approach. A nonmicrofocal rotating anode source is combined with a high-resolution detector and an absorbing mask to obtain attenuation, phase, and ultra-small-angle scattering tomograms of different specimens. A theoretical model is also presented which justifies the implementation of beam tracking with polychromatic sources and provides quantitative values of attenuation and phase, under the assumption of low sample attenuation. The method is tested on a variety of samples featuring both large and small x-ray attenuation, phase, and scattering signals. The complementarity of the contrast channels can enable subtle distinctions between materials and tissue types, which appear indistinguishable to conventional tomography scanners

Magnetic deflections and possible sources of the ultra-high-energy cosmic rays in the AGASA-HiRes-Yakutsk cluster

The cluster of ultra-high-energy cosmic rays observed by the AGASA, HiRes and Yakutsk experiments is studied with respect to possible deflections of particles in regular magnetic fields. Best-fit positions of a potential source of these clustered particles are found, with account of the errors in energy estimation, both in the frameworks of particular models of the Galactic magnetic field and treating the direction and the amount of deflection as free parameters. The study suggests that an unknown regular component of either Galactic or extragalactic magnetic field may dominate over modelled components in the direction of the cluster. Possible sources of the cosmic rays in that direction are considered.Comment: 18 pages, 3 eps figures, iopart.cl

Development of a porcine acellular bladder matrix for tissue-engineered bladder reconstruction

PURPOSE: Enterocystoplasty is adopted for patients requiring bladder augmentation, but significant long-term complications highlight need for alternatives. We established a protocol for creating a natural-derived bladder extracellular matrix (BEM) for developing tissue-engineered bladder, and investigated its structural and functional characteristics. METHODS: Porcine bladders were de-cellularised with a dynamic detergent-enzymatic treatment using peristaltic infusion. Samples and fresh controls were evaluated using histological staining, ultrastructure (electron microscopy), collagen, glycosaminoglycans and DNA quantification and biomechanical testing. Compliance and angiogenic properties (Chicken chorioallantoic membrane [CAM] assay) were evaluated. T test compared stiffness and glycosaminoglycans, collagen and DNA quantity. p value of < 0.05 was regarded as significant. RESULTS: Histological evaluation demonstrated absence of cells with preservation of tissue matrix architecture (collagen and elastin). DNA was 0.01 μg/mg, significantly reduced compared to fresh tissue 0.13 μg/mg (p < 0.01). BEM had increased tensile strength (0.259 ± 0.022 vs 0.116 ± 0.006, respectively, p < 0.0001) and stiffness (0.00075 ± 0.00016 vs 0.00726 ± 0.00216, p = 0.011). CAM assay showed significantly increased number of convergent allantoic vessels after 6 days compared to day 1 (p < 0.01). Urodynamic studies showed that BEM maintains or increases capacity and compliance. CONCLUSION: Dynamic detergent-enzymatic treatment produces a BEM which retains structural characteristics, increases strength and stiffness and is more compliant than native tissue. Furthermore, BEM shows angiogenic potential. These data suggest the use of BEM for development of tissue-engineered bladder for patients requiring bladder augmentation