The protoMIRAX Hard X-ray Imaging Balloon Experiment

The protoMIRAX hard X-ray imaging telescope is a balloon-borne experiment developed as a pathfinder for the MIRAX satellite mission. The experiment consists essentially in a coded-aperture hard X-ray (30-200 keV) imager with a square array (13$\times$13) of 2mm-thick planar CZT detectors with a total area of 169 cm$^2$. The total, fully-coded field-of-view is $21^{\circ}\times 21^{\circ}$ and the angular resolution is 1$^{\circ}$43'. In this paper we describe the protoMIRAX instrument and all the subsystems of its balloon gondola, and we show simulated results of the instrument performance. The main objective of protoMIRAX is to carry out imaging spectroscopy of selected bright sources to demonstrate the performance of a prototype of the MIRAX hard X-ray imager. Detailed background and imaging simulations have been performed for protoMIRAX balloon flights. The 3$\sigma$ sensitivity for the 30-200 keV range is ~1.9 $\times$ 10$^{-5}$ photons cm$^{-2}$ s$^{-1}$ for an integration time of 8 hs at an atmospheric depth of 2.7 g cm$^{-2}$ and an average zenith angle of 30$^{\circ}$. We have developed an attitude control system for the balloon gondola and new data handling and ground systems that also include prototypes for the MIRAX satellite. We present the results of Monte Carlo simulations of the camera response at balloon altitudes, showing the expected background level and the detailed sensitivity of protoMIRAX. We also present the results of imaging simulations of the Crab region. The results show that protoMIRAX is capable of making spectral and imaging observations of bright hard X-ray source fields. Furthermore, the balloon observations will carry out very important tests and demonstrations of MIRAX hardware and software in a near space environment.Comment: 9 pages, 13 figures, accepted for publication in Astronomy & Astrophysic

i-Rheo: determining the linear viscoelastic moduli of colloidal dispersions from step-stress measurements

We report on the application of a Fourier transform based method, `i-Rheo', to evaluate the linear viscoelastic moduli of hard-sphere colloidal dispersions, both in the fluid and glass states, from a direct analysis of raw step-stress (creep) experimental data. We corroborate the efficacy of i-Rheo by comparing the outputs of creep tests performed on homogenous complex fluids to conventional dynamic frequency sweeps. A similar approach is adopted for a number of colloidal suspensions over a broad range of volume fractions. For these systems, we test the limits of the method by varying the applied stress across the materials' linear and non-linear viscoelastic regimes, and we show that the best results are achieved for stress values close to the upper limit of the materials' linear viscoelastic regime; where the signal-to-noise ratio is at its highest and the non-linear phenomena have not appeared yet. We record that, the range of accessible frequencies is controlled at the higher end by the relative weight between the inertia of the instrument and the elasticity of the complex material under investigation; whereas, the lowest accessible frequency is dictated by the extent of the materials' linear viscoelastic regime. Nonetheless, despite these constrains, we confirm the effectiveness of i-Rheo for gaining valuable information on the materials' linear viscoelastic properties even from creep ringing data, confirming its potency and general validity as an accurate method for determining the material's rheological behaviour for a variety of complex systems

Identification of a GCC transcription factor responding to fruit colour change events in citrus through the transcriptomic analyses of two mutants

14 páginas, 6 figuras, 3 tablas.[Background]: External ripening in Citrus fruits is morphologically characterized by a colour shift from green to orange due to the degradation of chlorophylls and the accumulation of carotenoid pigments. Although numerous genes coding for enzymes involved in such biochemical pathways have been identified, the molecular control of this process has been scarcely studied. In this work we used the Citrus clementina mutants 39B3 and 39E7, showing delayed colour break, to isolate genes potentially related to the regulation of peel ripening and its physiological or biochemical effects. [Results]: Pigment analyses revealed different profiles of carotenoid and chlorophyll modification in 39B3 and 39E7 mutants. Flavedo from 39B3 fruits showed an overall delay in carotenoid accumulation and chlorophyll degradation, while the flavedo of 39E7 was devoid of the apocarotenoid β-citraurin among other carotenoid alterations. A Citrus microarray containing about 20,000 cDNA fragments was used to identify genes that were differentially expressed during colour change in the flavedo of 39B3 and 39E7 mutants respect to the parental variety. The results highlighted 73 and 90 genes that were respectively up- and down-regulated in both mutants. CcGCC1 gene, coding for a GCC type transcriptional factor, was found to be down-regulated. CcGCC1 expression was strongly induced at the onset of colour change in the flavedo of parental clementine fruit. Moreover, treatment of fruits with gibberellins, a retardant of external ripening, delayed both colour break and CcGCC1 overexpression. [Conclusions]: In this work, the citrus fruit ripening mutants 39B3 and 39E7 have been characterized at the phenotypic, biochemical and transcriptomic level. A defective synthesis of the apocarotenoid β-citraurin has been proposed to cause the yellowish colour of fully ripe 39E7 flavedo. The analyses of the mutant transcriptomes revealed that colour change during peel ripening was strongly associated with a major mobilization of mineral elements and with other previously known metabolic and photosynthetic changes. The expression of CcGCC1 was associated with peel ripening since CcGCC1 down-regulation correlated with a delay in colour break induced by genetic, developmental and hormonal causes.Work was supported by grants AGL2007-65437-C04-01/AGR (Centro de Genómica) and AGL2009-11558 (L. Zacarías and M. J. Rodrigo) from the Ministerio de Educación y Ciencia of Spain.Peer reviewe

Special issue on the 2nd E3 Mediterranean symposium foreword

As Guest Editors, we are delighted to introduce this Special Issue made to celebrate the '2nd E3 Mediterranean Symposium: Electrochemistry for Environment and Energy', which was held in Palazzo Feltrinelli, Gargnano, Italy, from 14 to 16 September 2016 following the 'Giornate dell'Elettrochimica Italiana'

Effect of the air pressure on electro-Fenton process

Electro-Fenton process is considered a very promising tool for the treatment of waste waters contaminated by organic pollutants refractant or toxic for microorganisms used in biological processes [1-6]. In these processes H2O2 is continuously supplied to an acidic aqueous solution contained in an electrolytic cell from the two-electron reduction of oxygen gas, directly injected as pure gas or bubbled air. Due to the poor solubility of O2 in aqueous solutions, two dimensional cheap graphite or carbon felt electrodes give quite slow generation of H2O2, thus resulting in a slow abatement of organics. In this context, we report here a series of studies [7-9] on the effect of air pressure on the electro-generation of H2O2 and the abatement of organic pollutants in water by electro-Fenton process. The effect of air pressure, current density, mixing and nature of the organic pollutant was evaluated. [1] E. Brillas, I. Sirés, M.A. Oturan, Chem. Rev., 109 (2009) 6570-6631. [2] C.A. Martínez-Huitle, M.A. Rodrigo, I. Sirés, O. Scialdone, Chem. Rev. 115 (2015) 13362–13407. [3] M. Panizza, G. Cerisola, Chem. Rev. 109 (2009) 6541–6569. [4] I. Sirés, E. Brillas, M.A. Oturan, M.A. Rodrigo, M. Panizza, Environ. Sci. Pollut. Res. 21 (2014) 8336–8367. [5] C.A. Martínez-Huitle, S. Ferro, Chem. Soc. Rev. 35 (2006) 1324–1340. [6] B.P.P. Chaplin, Environ. Sci. Process. Impacts. 16 (2014) 1182–1203. [7] O. Scialdone, A. Galia, C. Gattuso, S. Sabatino, B. Schiavo, Electrochim. Acta, 182 (2015) 775-780. [8] J.F. Pérez, A. Galia, M.A. Rodrigo, J. Llanos, S. Sabatino, C. Sáez, B. Schiavo, O. Scialdone, Electrochim. Acta, 248 (2017) 169-177. [9] A.H. Ltaïef, S. Sabatino, F. Proietto, A. Galia, O. Scialdone, O. 2018, Chemosphere, 202, 111-118

Evaluación de la cariogenicidad de Actinomyces naeslundii, Streptococcus gordonii y Streptococcus mutans en un modelo de biofilm multiespecies

58 p.Objetivo: La formación de biopelículas y cariogenicidad difieren mucho entre las distintas especies que pueblan el biofilm oral. Estas bacterias también pueden competir para prevalecer durante el desarrollo del biofilm. La mayoría de los estudios sobre el metabolismo de los hidratos de carbono por las bacterias cariogénicas se han llevado a cabo usando biofilm monoespecies o duales. El modelo de biofilms con más de dos especies es escasamente reportado y sólo unos pocos informes han abordado esta cuestión. Por lo tanto, el propósito de este estudio fue determinar la cariogenicidad sobre el esmalte de A. naeslundii, S. gordonii, y S. mutans después que ellos formaron parte de un modelo de biopelícula multiespecies. Materiales y Métodos: Biofilms de A. naeslundii ATCC12104, S. gordonii ATCC35105 y S. mutans UA159 y las tres especies juntas fueron cultivados, sobre bloques de esmalte bovino y crecidos en caldo de cultivo triptona-extracto de levadura ultrapurificado (UYTEB) con glucosa al 1% a 37ºC y 10% CO2, durante 4 días. Ocho veces al día los biofilms fueron expuestos a 10% de sacarosa. El pH de los medios de cultivo se determinó 2 veces por día. En el día 5 los biofilms fueron colectados para la evaluación de: a) biomasa de biofilms (viabilidad bacteriana, peso húmedo), b) concentración extracelular de polisacáridos solubles e insolubles, c) concentración de polisacáridos intracelulares, d) observación de las biopelículas mediante microscopía electrónica de barrido y microscopía confocal. La desmineralización de los bloques dentarios fue estimada por el porcentaje de pérdida de microdureza superficial (%PDS). Los resultados se compararon entre biofilms monospecies y multiespecies a un nivel de significación del 95%. Resultados: S. mutans solo fue más acidogénica (pH a 82 h: 4,41 ± 0,10, n= 6), mostrando una mayor concentración de polisacáridos extracelulares insolubles (15,8 ± 6,1, n=6) e induciendo más %PDS en el esmalte (45,3 ± 4,8, n= 6) que las otras especies que crecen en biofilms monoespecies, pero también del multiespecies. Conclusiones: Los datos sugieren que cariogenicidad de S. mutans se ve obstaculizada cuando crece junto con S. gordonii y A. naeslundii en una biopelícula multiespecífica. Palabras clave: Biofilm multiespecies, A. naeslundii, S. gordonii, S. mutans, cariogenicidad, sacarosa./ABSTRACT: Assessment of the cariogenicity of Actinomyces naeslundii, Streptococcus gordonii and Streptococcus mutans on a multispecies biofilm model. Objective: Biofilm formation and cariogenicity greatly differ among the various species populating the oral biofilm. These bacteria can also compete to prevail during the development of the biofilm. Studies dealing with the metabolism of carbohydrates by cariogenic bacteria have mostly carried out using mono or dual-species biofilms. Modeling using more than two species is scarce and only few reports have addresses this issue. Therefore, the purpose of this study was to determine cariogenicity on enamel of A. naeslundii, S. gordonii, and S. mutans after when they are forming part of a multispecies biofilm model. Materials and Methods: Biofilms of A. naeslundii ATCC12104, S. gordonii ATCC35105 and S. mutans UA159 by separate and together were grown on bovine enamel slabs into tryptone-yeast extract ultrapurified (UYTEB) growth medium, supplemented with 1% glucose at 37°C and 10% CO2 for 4 days. Eight times a day biofilms were exposed to 10% sucrose. The pH of the culture media was determined twice per day. On day 5, biofilms were collected for assessment of: a) biofilms biomass (bacterial viability, wet weight), b) extracellular concentration of soluble and insoluble polysaccharides, c) concentration of intracellular polysaccharides and d) observation of the biofilms by SEM and confocal microscopy. Demineralization of the slabs was estimated by the percentage of surface microhardness loss (%SHL). Results were compared between monospecies and multispecies biofilms at a level of 95% of significance. Results: S. mutans alone was more acidogenic (pH at 82 h: 4.41±0.10, n=6), showing higher concentration of insoluble extracellular polysaccharides (15.8±6.1, n=6) and inducing more %SHL in enamel (45.3±4.8, n=6) than the other species growing in monoespecies, but also than the multispecies. Conclusions: Data suggest that cariogenicity of S. mutans is hampered when it grows along with S. gordonii and A. naeslundii in a multispecies biofilm. Keywords: Multispecies biofilm, S. gordonii, S. mutans, A. naeslundii, carcinogenicity, sucrose

Sono- and photoelectrocatalytic processes for the removal of ionic liquids based on the 1-butyl-3-methylimidazolium cation

This Accepted Manuscript will be available for reuse under a CC BY-NC-ND license after 24 months of embargo periodIn this work, sono- and photoelectrolysis of synthetic wastewaters polluted with the ionic liquids 1-Butyl-3-methylimidazolium acetate (BmimAc)and chloride (BmimCl)were investigated with diamond anodes. The results were compared to those attained by enhancing bare electrolysis with irradiation by UV light or with the application of high-frequency ultrasound (US). Despite its complex heterocyclic structure, the Bmim+ cation was successfully depleted with the three technologies that were tested and was mainly transformed into four different organic intermediates, an inorganic nitrogen species and carbon dioxide. Regardless of the technology that was evaluated, removal of the heterocyclic ring is much less efficient (and much slower)than oxidation of the counter ion. In turn, the counter ion influences the rate of removal of the ionic liquid cation. Thus, the electrolysis and photoelectrolysis of BmimAc are much less efficient than sonoelectrolysis, but their differences become much less important in the case of BmimCl. In this later case, the most efficient technology is photoelectrolysis. This result is directly related to the generation of free radicals in the solution by irradiation of the electrochemical system with UV light, which contributes significantly to the removal of Bmim+The authors gratefully appreciate financial support from the Spanish MICINN (CTM2016-76197-R and CTM2016-76564-R, European Union (AEI/FEDER, UE) and Consejería de Educación of the CM (REMTAVARES S2013/MAE-2716). I. F. Mena wishes to thank the Spanish MINECO and the ESF for a research gran

Use of Gene Therapy in a Subcutaneous Murine Model of Lung Cancer

OBJECTIVE: To assess the effectiveness of in vivo gene therapy to treat subcutaneous tumors generated from murine lung cancer cells. MATERIAL AND METHODS: C57BL/6 mice received subcutaneus injections of 5×105 cells from the murine Lewis lung cancer cell line. By 10 days, subcutaneous tumors of approximately 5 mm diameter were formed. At that point, treatment was provided by intratumor injection of a replication-defective recombinant adenovirus carrying the gene for thymidine kinase (AdCMV-Tk) or interleukin (IL) 12 (AdCMV-IL12), or by injection of syngeneic dendritic cells previously transduced with adenovirus containing the IL-12 gene (DC-IL12). Control groups were treated with saline or adenovirus containing the gene for β-galactosidase (AdCMV-LacZ), which functions as a reporter gene and does not have a therapeutic effect. The number of animals in each group ranged from 14 to 25 in experiments using adenovirus and from 10 to 12 in experiments using dendritic cells. Tumor size was followed for 3 weeks in the case of treatment with adenovirus and 4 weeks for treatment with dendritic cells. RESULTS: A significant reduction in subcutaneous tumor growth was observed in the groups treated with AdCMVTk, AdCMV-IL12, and DC-IL12 compared with control groups treated with saline or AdCMV-LacZ. The difference was statistically significant from day 7 of treatment in the AdCMV-Tk group, from day 9 in the AdCMV-IL12 group, and from day 10 in the DC-IL12 group, and in all cases it was maintained until the end of the follow-up period. CONCLUSIONS: Gene therapy with AdCMV-Tk, AdCMVIL12, or DC-IL12 is effective in our model of subcutaneous tumors arising from cells of the Lewis lung cancer cell line. The treatment leads to a significant reduction in tumor growth compared with control groups