590 research outputs found
Quantization of the open string on plane-wave limits of dS_n x S^n and non-commutativity outside branes
The open string on the plane-wave limit of with constant
and dilaton background fields is canonically quantized. This entails
solving the classical equations of motion for the string, computing the
symplectic form, and defining from its inverse the canonical commutation
relations. Canonical quantization is proved to be perfectly suited for this
task, since the symplectic form is unambiguously defined and non-singular. The
string position and the string momentum operators are shown to satisfy
equal-time canonical commutation relations. Noticeably the string position
operators define non-commutative spaces for all values of the string
world-sheet parameter \sig, thus extending non-commutativity outside the
branes on which the string endpoints may be assumed to move. The Minkowski
spacetime limit is smooth and reproduces the results in the literature, in
particular non-commutativity gets confined to the endpoints.Comment: 31 pages, 12p
Incorporation by coordination and release of the iron chelator drug deferiprone from zinc-based metalâorganic frameworks
A series of new zinc-based metalâorganic framework materials has been prepared in which deferiprone is incorporated as a chelating ligand on infinite or tri-zinc secondary building units following deprotonation. Deferiprone is immediately released from the MOFs on treatments with 1 N hydrochloric acid or buffer, but slow release is observed in ethanoic acid
D-branes with Lorentzian signature in the Nappi-Witten model
Lorentzian signature D-branes of all dimensions for the Nappi-Witten string
are constructed. This is done by rewriting the gluing condition for
the model chiral currents on the brane as a well posed first order differential
problem and by solving it for Lie algebra isometries other than Lie algebra
automorphisms. By construction, these D-branes are not twined conjugacy
classes. Metrically degenerate D-branes are also obtained.Comment: 22 page
Phylogeographic patterns of Capreolus capreolus in the centre of the Iberian peninsula
One hundred and one samples of muscle tissue were obtained from roe deer in the centre of the Iberian peninsula. We compared the sequences of the control region (Dâloop) of the mitochondrial DNA of these samples with those obtained in previous studies. Adding the information from microsatellite markers and derived genetic parameters to study the population structure, we found a philopatric structure, with females maintaining mitochondrial haplotype diversity, while males showed a pattern of genome homogenization. The population can thus be considered panmictic. Different times of palaeohistory of the species may explain these results: glacialâinterglacial stages of the Pleistocene and the reduction and recovery of populations throughout the 20th century
Plasma and cerebrospinal fluid concentrations of linezolid in neurosurgical critically ill patients with proven or suspected central nervous system infections
Linezolid is a valuable treatment option for central nervous system (CNS) infections caused by multidrug-resistant Gram-positive micro-organisms. Data regarding its penetration into the CNS have shown wide variability. The aim of this study was to describe the population pharmacokinetics of linezolid in plasma and cerebrospinal fluid (CSF) in critically ill patients with external CSF drainage and proven or suspected CNS infections. This was an observational pharmacokinetic (PK) study in 11 critically ill patients with proven or suspected CNS infection receiving linezolid. Serial blood and CSF samples were taken and were subject to population PK analysis. The median (interquartile range) of AUC(0-12h) was 47.6 (17.9-58.6) mg h/L in plasma and 21.1(18.8-30.4) mg h/L in CSF, with a median CSF/plasma ratio of 0.77. At pre-dose at steady state, a strong positive correlation was observed between linezolid concentrations in CSF and plasma (Spearman's rho = 0.758; P = 0.011). For a minimum inhibitory concentration (MIC) of 2 mg/L, the median AUC(0-24h)/MIC values in plasma and CSF wer
Bismuth coordination networks containing deferiprone: synthesis, characterisation, stability and antibacterial activity
A series of bismuthâdicarboxylateâdeferiprone coordination networks have been prepared and structurally characterised. The new compounds have been demonstrated to release the iron overload drug deferiprone on treatment with PBS and have also been shown to have antibacterial activity against H. pylori
Geometric construction of D-branes in WZW models
The geometric description of D-branes in WZW models is pushed forward. Our
starting point is a gluing condition\, that matches the model's
chiral currents at the worldsheet boundary through a linear map acting on
the WZW Lie algebra. The equivalence of boundary and gluing conditions of this
type is studied in detail. The analysis involves a thorough discussion of
Frobenius integrability, shows that must be an isometry, and applies to
both metrically degenerate and nondegenerate D-branes. The isometry need
not be a Lie algebra automorphism nor constantly defined over the brane. This
approach, when applied to isometries of the form with a constant Lie
algebra automorphism, validates metrically degenerate -twined conjugacy
classes as D-branes. It also shows that no D-branes exist in semisimple WZW
models for constant\, .Comment: 23 pages, discussion of limitations of the gluing condition approach
adde
MOFs as multifunctional catalysts: One-pot synthesis of menthol from citronellal over a bifunctional MIL-101 catalyst
A bifunctional MOF catalyst containing coordinatively unsaturated Cr3+ sites and palladium nanoparticles (Pd@MIL-101) has been used for the cyclization of citronellal to isopulegol and for the one-pot tandem isomerization/hydrogenation of citronellal to menthol. The MOF was found to be stable under the reaction conditions used, and the results obtained indicate that the performance of this bifunctional solid catalyst is comparable with other state-of-the-art materials for the tandem reaction: Full citronellal conversion was attained over Pd@MIL-101 in 18 h, with 86% selectivity to menthols and a diastereoselectivity of 81% to the desired (-)-menthol, while up to 30 h were necessary for attaining similar values over Ir/H-beta under analogous reaction conditions.Financial support by Ministerio de Educacion y Ciencia e Innovacion (Project MIYCIN, CSD2009-00050; PROGRAMA CONSOLIDER. INGENIO 2009), Generalidad Valenciana (GV PROMETEO/2008/130) and the CSIC (Proyectos Intramurales Especiales 201080I020) is gratefully acknowledged.GarcĂa Cirujano, F.; LlabrĂ©s I Xamena, FX.; Corma CanĂłs, A. (2012). MOFs as multifunctional catalysts: One-pot synthesis of menthol from citronellal over a bifunctional MIL-101 catalyst. Dalton Transactions. 41:4249-4254. https://doi.org/10.1039/c2dt12480gS4249425441Corma, A., GarciÌa, H., & LlabreÌs i Xamena, F. X. (2010). Engineering Metal Organic Frameworks for Heterogeneous Catalysis. Chemical Reviews, 110(8), 4606-4655. doi:10.1021/cr9003924Farrusseng, D., Aguado, S., & Pinel, C. (2009). Metal-Organic Frameworks: Opportunities for Catalysis. Angewandte Chemie International Edition, 48(41), 7502-7513. doi:10.1002/anie.200806063Lee, J., Farha, O. K., Roberts, J., Scheidt, K. A., Nguyen, S. T., & Hupp, J. T. (2009). Metalâorganic framework materials as catalysts. Chemical Society Reviews, 38(5), 1450. doi:10.1039/b807080fWang, Z., & Cohen, S. M. (2009). Postsynthetic modification of metalâorganic frameworks. Chemical Society Reviews, 38(5), 1315. doi:10.1039/b802258pBanerjee, M., Das, S., Yoon, M., Choi, H. J., Hyun, M. H., Park, S. M., ⊠Kim, K. (2009). Postsynthetic Modification Switches an Achiral Framework to Catalytically Active Homochiral MetalâOrganic Porous Materials. Journal of the American Chemical Society, 131(22), 7524-7525. doi:10.1021/ja901440gGASCON, J., AKTAY, U., HERNANDEZALONSO, M., VANKLINK, G., & KAPTEIJN, F. (2009). Amino-based metal-organic frameworks as stable, highly active basic catalysts. Journal of Catalysis, 261(1), 75-87. doi:10.1016/j.jcat.2008.11.010Hasegawa, S., Horike, S., Matsuda, R., Furukawa, S., Mochizuki, K., Kinoshita, Y., & Kitagawa, S. (2007). Three-Dimensional Porous Coordination Polymer Functionalized with Amide Groups Based on Tridentate Ligand: Selective Sorption and Catalysis. Journal of the American Chemical Society, 129(9), 2607-2614. doi:10.1021/ja067374yCho, S.-H., Ma, B., Nguyen, S. T., Hupp, J. T., & Albrecht-Schmitt, T. E. (2006). A metalâorganic framework material that functions as an enantioselective catalyst for olefin epoxidation. Chem. Commun., (24), 2563-2565. doi:10.1039/b600408cZhang, X., LlabrĂ©s i Xamena, F. X., & Corma, A. (2009). Gold(III) â metal organic framework bridges the gap between homogeneous and heterogeneous gold catalysts. Journal of Catalysis, 265(2), 155-160. doi:10.1016/j.jcat.2009.04.021Meilikhov, M., Yusenko, K., Esken, D., Turner, S., Van Tendeloo, G., & Fischer, R. A. (2010). Metals@MOFs - Loading MOFs with Metal Nanoparticles for Hybrid Functions. European Journal of Inorganic Chemistry, 2010(24), 3701-3714. doi:10.1002/ejic.201000473Henschel, A., Gedrich, K., Kraehnert, R., & Kaskel, S. (2008). Catalytic properties of MIL-101. Chemical Communications, (35), 4192. doi:10.1039/b718371bVermoortele, F., Ameloot, R., Vimont, A., Serre, C., & De Vos, D. (2011). An amino-modified Zr-terephthalate metalâorganic framework as an acidâbase catalyst for cross-aldol condensation. Chem. Commun., 47(5), 1521-1523. doi:10.1039/c0cc03038dWu, P., Wang, J., Li, Y., He, C., Xie, Z., & Duan, C. (2011). Luminescent Sensing and Catalytic Performances of a Multifunctional Lanthanide-Organic Framework Comprising a Triphenylamine Moiety. Advanced Functional Materials, 21(14), 2788-2794. doi:10.1002/adfm.201100115Pan, Y., Yuan, B., Li, Y., & He, D. (2010). Multifunctional catalysis by Pd@MIL-101: one-step synthesis of methyl isobutyl ketone over palladium nanoparticles deposited on a metalâorganic framework. Chemical Communications, 46(13), 2280. doi:10.1039/b922061eCliment, M. J., Corma, A., Guil-LĂłpez, R., Iborra, S., & Primo, J. (1998). Use of Mesoporous MCM-41 Aluminosilicates as Catalysts in the Preparation of Fine Chemicals. Journal of Catalysis, 175(1), 70-79. doi:10.1006/jcat.1998.1970Climent, M. J., Corma, A., Iborra, S., & Velty, A. (2002). Designing the adequate base solid catalyst with Lewis or Bronsted basic sites or with acidâbase pairs. Journal of Molecular Catalysis A: Chemical, 182-183, 327-342. doi:10.1016/s1381-1169(01)00501-5Boronat, M., Climent, M. J., Corma, A., Iborra, S., MontĂłn, R., & Sabater, M. J. (2010). Bifunctional Acid-Base Ionic Liquid Organocatalysts with a Controlled Distance Between Acid and Base Sites. Chemistry - A European Journal, 16(4), 1221-1231. doi:10.1002/chem.200901519Corma, A., DiÌaz, U., GarciÌa, T., Sastre, G., & Velty, A. (2010). Multifunctional Hybrid OrganicâInorganic Catalytic Materials with a Hierarchical System of Well-Defined Micro- and Mesopores. Journal of the American Chemical Society, 132(42), 15011-15021. doi:10.1021/ja106272zFerey, G. (2005). A Chromium Terephthalate-Based Solid with Unusually Large Pore Volumes and Surface Area. Science, 309(5743), 2040-2042. doi:10.1126/science.1116275Corma, A., & Renz, M. (2004). Sn-Beta zeolite as diastereoselective water-resistant heterogeneous Lewis-acid catalyst for carbonâcarbon bond formation in the intramolecular carbonylâene reaction. Chem. Commun., (5), 550-551. doi:10.1039/b313738dIosif, F., Coman, S., PĂąrvulescu, V., Grange, P., Delsarte, S., Vos, D. D., & Jacobs, P. (2004). Ir-Beta zeolite as a heterogeneous catalyst for the one-pot transformation of citronellal to menthol. Chem. Commun., (11), 1292-1293. doi:10.1039/b403692aNeaĆŁu, F., Coman, S., PĂąrvulescu, V. I., Poncelet, G., De Vos, D., & Jacobs, P. (2009). Heterogeneous Catalytic Transformation of Citronellal to Menthol in a Single Step on Ir-Beta Zeolite Catalysts. Topics in Catalysis, 52(9), 1292-1300. doi:10.1007/s11244-009-9270-9MERTENS, P., VERPOORT, F., PARVULESCU, A., & DEVOS, D. (2006). Pt/H-beta zeolites as productive bifunctional catalysts for the one-step citronellal-to-menthol conversion. Journal of Catalysis, 243(1), 7-13. doi:10.1016/j.jcat.2006.06.017Da Silva Rocha, K. A., Robles-Dutenhefner, P. A., Sousa, E. M. B., Kozhevnikova, E. F., Kozhevnikov, I. V., & Gusevskaya, E. V. (2007). Pdâheteropoly acid as a bifunctional heterogeneous catalyst for one-pot conversion of citronellal to menthol. Applied Catalysis A: General, 317(2), 171-174. doi:10.1016/j.apcata.2006.10.019Trasarti, A. F., Marchi, A. J., & ApesteguıÌa, C. R. (2004). Highly selective synthesis of menthols from citral in a one-step process. Journal of Catalysis, 224(2), 484-488. doi:10.1016/j.jcat.2004.03.016TRASARTI, A., MARCHI, A., & APESTEGUIA, C. (2007). Design of catalyst systems for the one-pot synthesis of menthols from citral. Journal of Catalysis, 247(2), 155-165. doi:10.1016/j.jcat.2007.01.016Alaerts, L., SĂ©guin, E., Poelman, H., Thibault-Starzyk, F., Jacobs, P. A., & De Vos, D. E. (2006). Probing the Lewis Acidity and Catalytic Activity of the MetalâOrganic Framework [Cu3(btc)2] (BTC=Benzene-1,3,5-tricarboxylate). Chemistry - A European Journal, 12(28), 7353-7363. doi:10.1002/chem.200600220Horcajada, P., SurblĂ©, S., Serre, C., Hong, D.-Y., Seo, Y.-K., Chang, J.-S., ⊠FĂ©rey, G. (2007). Synthesis and catalytic properties of MIL-100(Fe), an iron(iii) carboxylate with large pores. Chem. Commun., (27), 2820-2822. doi:10.1039/b704325bRavon, U., Chaplais, G., Chizallet, C., Seyyedi, B., Bonino, F., Bordiga, S., ⊠Farrusseng, D. (2010). Investigation of Acid Centers in MIL-53(Al, Ga) for BrĂžnsted-Type Catalysis: Inâ
Situ FTIR and Abâ
Initio Molecular Modeling. ChemCatChem, 2(10), 1235-1238. doi:10.1002/cctc.201000055Vimont, A., Leclerc, H., Maugé, F., Daturi, M., Lavalley, J.-C., Surblé, S., ⊠Férey, G. (2007). Creation of Controlled BrÞnsted Acidity on a Zeotypic Mesoporous Chromium(III) Carboxylate by Grafting Water and Alcohol Molecules. The Journal of Physical Chemistry C, 111(1), 383-388. doi:10.1021/jp064686
Recommended from our members
Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016.
[This corrects the article DOI: 10.1186/s13054-016-1208-6.]
Economic evaluation of the treatment of Acute Bacterial Skin and Skin Structure Infections (ABSSSIs) from the national payer perspective : introduction of a new treatment to the patient journey. A simulation of three European countries
The aim of this study was to develop a spending predictor model to evaluate the direct costs associated with the management of ABSSSIs from the National health-care provider's perspective of Italy, Romania, and Spain.
METHODOLOGY:
A decision-analytic model was developed to evaluate the diagnostic and clinical pathways of hospitalized ABSSSI patients based on scientific guidelines and real-world data. A Standard of Care (SoC) scenario was compared with a dalbavancin scenario in which the patients could be discharged early. The epidemiological and cost parameters were extrapolated from national administrative databases (i.e., hospital information system). A probabilistic sensitivity analysis (PSA) and one-way sensitivity analysis (OWA) were performed.
RESULTS:
Overall, the model estimated an average annual number of patients with ABSSSIs of approximately 50,000 in Italy, Spain, and Romania. On average, the introduction of dalbavancin reduced the length of stay by 3.3 days per ABSSSI patient. From an economic perspective, dalbavancin did not incur any additional cost from the National Healthcare perspective, and the results were consistent among the countries. The PSA and OWA demonstrated the robustness of these results.
CONCLUSION:
This model represents a useful tool for policymakers by providing information regarding the economic and organizational consequences of an early discharge approach in ABSSSI management
- âŠ