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 $J_+=FJ_-$ for the model chiral currents on the brane as a well posed first order differential problem and by solving it for Lie algebra isometries $F$ 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

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\, $J_{+}=FJ_-$ that matches the model's chiral currents at the worldsheet boundary through a linear map $F$ 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 $F$ must be an isometry, and applies to both metrically degenerate and nondegenerate D-branes. The isometry $F$ need not be a Lie algebra automorphism nor constantly defined over the brane. This approach, when applied to isometries of the form $F=R$ with $R$ a constant Lie algebra automorphism, validates metrically degenerate $R$-twined conjugacy classes as D-branes. It also shows that no D-branes exist in semisimple WZW models for constant\, $F=-R$.Comment: 23 pages, discussion of limitations of the gluing condition approach adde

A simple and robust high-performance liquid chromatography coupled to a diode-array detector method for the analysis of genistein in mouse tissues

A simple liquid-liquid extraction procedure and quantification by high-performance liquid chromatography (HPLC) method coupled to a diode-array detector (DAD) of genistein (GEN) was developed in various mouse biological matrices. 7-ethoxycoumarin was used as internal standard (IS) and peaks were optimally separated using a Kinetex C18 column (2.6 µm, 150 mm X 2.10 mm I.D.) at 40 ºC with an isocratic elution of mobile phase with sodium dihydrogen phosphate 0.01M in water at pH 2.5 and methanol (55:45, v/v), at a flow rate of 0.25 mL/min. The injection volume was 10 µL. In all cases, the range of GEN recovery was higher than 61%. The low limit of quantification (LLOQ) was 25 ng/mL. The linearity of the calibration curves was satisfactory in all cases as shown by correlation coefficients >0.996. The within-day and between-day precisions were <15% and the accuracy ranged in all cases between 90.14 and 106.05%. This method was successfully applied to quantify GEN in liver, spleen, kidney and plasma after intravenous administration of a single dose (30 mg/Kg) in female BALB/C mice

Chitosan-coated mesoporous MIL-100(Fe) nanoparticles as improved bio-compatible oral nanocarriers

Nanometric biocompatible Metal-Organic Frameworks (nanoMOFs) are promising candidates for drug delivery. Up to now, most studies have targeted the intravenous route, related to pain and severe complications; whereas nanoMOFs for oral administration, a commonly used non-invasive and simpler route, remains however unexplored. We propose here the biofriendly preparation of a suitable oral nanocarrier based on the benchmarked biocompatible mesoporous iron(III) trimesate nanoparticles coated with the bioadhesive polysaccharide chitosan (CS). This method does not hamper the textural/ structural properties and the sorption/release abilities of the nanoMOFs upon surface engineering. The interaction between the CS and the nanoparticles has been characterized through a combination of high resolution soft X-ray absorption and computing simulation, while the positive impact of the coating on the colloidal and chemical stability under oral simulated conditions is here demonstrated. Finally, the intestinal barrier bypass capability and biocompatibility of CS-coated nanoMOF have been assessed in vitro, leading to an increased intestinal permeability with respect to the noncoated material, maintaining an optimal biocompatibility. In conclusion, the preservation of the interesting physicochemical features of the CS-coated nanoMOF and their adapted colloidal stability and progressive biodegradation, together with their improved intestinal barrier bypass, make these nanoparticles a promising oral nanocarrier

Spatial distribution of sporocarp production of ECM fungi Amanita ponderosa Malençon & R. Heim during six consecutive years at a holm-oak forest (dehesa) in the Sierra de Aracena (Huelva)

Se ha estudiado durante seis años consecutivos el número y la localización de los esporocarpos de Amanita ponderosa Malençon & R. Heim en una parcela de 3 ha ubicada en un encinar adehesado localizado en el Parque Natural «Sierra de Aracena y Picos de Aroche» (Huelva). Los datos indican que las áreas productoras de setas presentan un tamaño y una forma similares año tras año, aunque algunas zonas específicas muestran variaciones que sugieren la existencia de cierta alternancia o vecería. Esta especie fructifica solamente en primavera durante seis a ocho semanas, desde mediados de febrero hasta abril, cuando comienza a ascender la temperatura media tras el invierno. Las diferencias observadas en la duración del periodo de fructificación y la producción total de setas dependen fundamentalmente de las lluvias y la temperatura. Los resultados sugieren que las lluvias tempranas a finales de verano o principios de otoño son cruciales para la fructificación de la primavera siguiente, y que las lluvias caídas durante el periodo de fructificación tienen una menor influencia. Durante el periodo de fructificación, la producción es muy dependiente de la temperatura del suelo

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.]

Cytotoxicity of nanoscaled metal–organic frameworks

A series of fourteen porous Metal–Organic Frameworks (MOFs) with different compositions (Fe, Zn, and Zr; carboxylates or imidazolates) and structures have been successfully synthesised at the nanoscale and fully characterised by XRPD, FTIR, TGA, N2 porosimetry, TEM, DLS and z-potential. Their toxicological assessment was performed using two different cell lines: human epithelial cells from foetal cervical carcinoma (HeLa) and murine macrophage cell line (J774). It appears that MOF nanoparticles (NPs) exhibit low cytotoxicity, comparable to those of other commercialised nanoparticulate systems, the less toxic being the Fe carboxylate and the more toxic being the zinc imidazolate NPs. The cytotoxicity values, higher in J774 cells than in HeLa cells, are mainly function of their composition and cell internalisation capacity. Finally, cell uptake of one of the most relevant Fe-MOF-NPs for drug vectorisation has been investigated by confocal microscopy studies, and indicates a faster kinetics of cell penetration within J774 compared to HeLa cells

Seasonal influenza risk in hospital healthcare workers is more strongly associated with household than occupational exposures: results from a prospective cohort study in Berlin, Germany, 2006/07

Background: Influenza immunisation for healthcare workers is encouraged to protect their often vulnerable patients but also due to a perceived higher risk for influenza. We aimed to compare the risk of influenza infection in healthcare workers in acute hospital care with that in non-healthcare workers over the same season. Methods: We conducted a prospective, multicentre cohort study during the 2006/07 influenza season in Berlin, Germany. Recruited participants gave serum samples before and after the season, and completed questionnaires to determine their relevant exposures and possible confounding factors. The main outcome measure was serologically confirmed influenza infection (SCII), defined as a fourfold or greater rise in haemagglutination inhibition antibody titres to a circulating strain of influenza (with post-season titre at least 1:40). Weekly mobile phone text messages were used to prompt participants to report respiratory illnesses during the influenza season. A logistic regression model was used to assess the influence of potential risk factors. Results: We recruited 250 hospital healthcare workers (mean age 35.7 years) and 486 non-healthcare workers (mean age 39.2 years) from administrative centres, blood donors and colleges. Overall SCII attack rate was 10.6%. Being a healthcare worker was not a risk factor for SCII (relative risk 1.1, p=0.70). The final multivariate model had three significant factors: living with children (odds ratio [OR] 3.7, p=0.005), immunization (OR 0.50, p=0.02), and - among persons living in households without children - ownership of a car (OR 3.0, p=0.02). Living with three or more children (OR 13.8,