Gas-phase photocatalytic oxidation of volatile organic compounds

Substances emitted into the atmosphere by human activities in urban and industrial areas cause environmental problems such as air quality degradation, respiratory diseases, climate change, global warming, and stratospheric ozone depletion. Volatile organic compounds (VOCs) are major air pollutants, emitted largely by industry, transportation and households. Many VOCs are toxic, and some are considered to be carcinogenic, mutagenic, or teratogenic. A wide spectrum of VOCs is readily oxidized photocatalytically. Photocatalytic oxidation (PCO) over titanium dioxide may present a potential alternative to air treatment strategies currently in use, such as adsorption and thermal treatment, due to its advantageous activity under ambient conditions, although higher but still mild temperatures may also be applied. The objective of the present research was to disclose routes of chemical reactions, estimate the kinetics and the sensitivity of gas-phase PCO to reaction conditions in respect of air pollutants containing heteroatoms in their molecules. Deactivation of the photocatalyst and restoration of its activity was also taken under consideration to assess the practical possibility of the application of PCO to the treatment of air polluted with VOCs. UV-irradiated titanium dioxide was selected as a photocatalyst for its chemical inertness, non-toxic character and low cost. In the present work Degussa P25 TiO2 photocatalyst was mostly used. In transient studies platinized TiO2 was also studied. The experimental research into PCO of following VOCs was undertaken: - methyl tert-butyl ether (MTBE) as the basic oxygenated motor fuel additive and, thus, a major non-biodegradable pollutant of groundwater; - tert-butyl alcohol (TBA) as the primary product of MTBE hydrolysis and PCO; - ethyl mercaptan (ethanethiol) as one of the reduced sulphur pungent air pollutants in the pulp-and-paper industry; - methylamine (MA) and dimethylamine (DMA) as the amino compounds often emitted by various industries. The PCO of VOCs was studied using a continuous-flow mode. The PCO of MTBE and TBA was also studied by transient mode, in which carbon dioxide, water, and acetone were identified as the main gas-phase products. The volatile products of thermal catalytic oxidation (TCO) of MTBE included 2-methyl-1-propene (2-MP), carbon monoxide, carbon dioxide and water; TBA decomposed to 2-MP and water. Continuous PCO of 4 TBA proceeded faster in humid air than dry air. MTBE oxidation, however, was less sensitive to humidity. The TiO2 catalyst was stable during continuous PCO of MTBE and TBA above 373 K, but gradually lost activity below 373 K; the catalyst could be regenerated by UV irradiation in the absence of gas-phase VOCs. Sulphur dioxide, carbon monoxide, carbon dioxide and water were identified as ultimate products of PCO of ethanethiol. Acetic acid was identified as a photocatalytic oxidation by-product. The limits of ethanethiol concentration and temperature, at which the reactor performance was stable for indefinite time, were established. The apparent reaction kinetics appeared to be independent of the reaction temperature within the studied limits, 373 to 453 K. The catalyst was completely and irreversibly deactivated with ethanethiol TCO. Volatile PCO products of MA included ammonia, nitrogen dioxide, nitrous oxide, carbon dioxide and water. Formamide was observed among DMA PCO products together with others similar to the ones of MA. TCO for both substances resulted in the formation of ammonia, hydrogen cyanide, carbon monoxide, carbon dioxide and water. No deactivation of the photocatalyst during the multiple long-run experiments was observed at the concentrations and temperatures used in the study. PCO of MA was also studied in the aqueous phase. Maximum efficiency was achieved in an alkaline media, where MA exhibited high fugitivity. Two mechanisms of aqueous PCO – decomposition to formate and ammonia, and oxidation of organic nitrogen directly to nitrite - lead ultimately to carbon dioxide, water, ammonia and nitrate: formate and nitrite were observed as intermediates. A part of the ammonia formed in the reaction was oxidized to nitrite and nitrate. This finding helped in better understanding of the gasphase PCO pathways. The PCO kinetic data for VOCs fitted well to the monomolecular Langmuir- Hinshelwood (L-H) model, whereas TCO kinetic behaviour matched the first order process for volatile amines and the L-H model for others. It should be noted that both LH and the first order equations were only the data fit, not the real description of the reaction kinetics. The dependence of the kinetic constants on temperature was established in the form of an Arrhenius equation.

Complications of guided surgery and immediate loading in oral implantology: a report of 12 cases

Objectives: The growing interest in minimally invasive surgery, together with the possibility of fitting prostheses with immediate function, have led to the development of software capable of planning and manufacturing a surgical guide and prosthesis that can be placed upon conclusion of the implant surgery step. The present study evaluates the surgical and prosthetic complications of implant treatment with the guided surgery technique, together with patient comfort during and after treatment. Patients and methods: A retrospective observational study was made of 19 patients with partially or totally edentulous upper and/or lower maxillae, involving the placement of a total of 122 implants. All cases were planned and operated upon with the guided surgery technique. Results: A total of 122 implants were placed in 14 males and 5 females. The intraoperative surgical complications comprised a lack of primary stability, while the postoperative complications consisted of infections and a lack of implant osteointegration. Ten implants failed. The prosthetic complications in turn comprised loosening of the provisional prosthesis screws, prosthesis tooth fracture, and a lack of passive fit of the immediate prosthesis. The degree of patient satisfaction was evaluated using a verbal scale. Conclusions: Implant restoration with the guided surgery technique and immediate functional loading is a predictable procedure, provided patient selection and the surgical technique are adequate, affording lesser postoperative morbidity and increased patient satisfaction thanks to the immediate restoration of esthetics and function

El Etnólogo como Conservador de Museo

Con cierta frecuencia uno se plantea la cuestión de cuál es el estatus profesional o científico de un etnólogo ocupado en la museografía etnográfica. Y, asimismo, uno también se pregunta cuál es la clase de problemática con la que se enfrenta comúnmente este tipo de Etnología, y cuál es su función en el seno de las ciencias antropológicas. Y la respuesta que nos damos, siempre es la misma: esta problemática no podemos reducirla al marco estricto de la museografía. En realidad, debe plantearse como una extensión de la problemática específica y general en que se inserta la etnología de cada país (cf. Esteva, 1969). En otro sentido, el papel del etnólogo que ejerce como conservador de un museo etnográfico está vinculado con la situación de su ciencia en el mundo contemporáneo.

Neuroplasticity: Unexpected Consequences of Early Blindness.

A pair of recent studies shows that congenital blindness can have significant consequences for the functioning of the visual system after sight restoration, particularly if that restoration is delayed.

Living with invasive plants in the Anthropocene : the importance of understanding practice and experience

The role of humans in facilitating the rapid spread of plants at a scale that is considered invasive is one manifestation of the Anthropocene, now framed as a geological period in which humans are the dominant force in landscape transformation. Invasive plant management faces intensified challenges, and can no longer be viewed in terms of 'eradication' or 'restoration of original landscapes'. In this perspectives piece, we focus on the practice and experience of people engaged in invasive plant management, using examples from Australia and Canada. We show how managers 1) face several pragmatic trade-offs; 2) must reconcile diverse views, even within stakeholder groups; 3) must balance competing temporal scales; 4) encounter tensions with policy; and 5) face critical and under-acknowledged labour challenges. These themes show the variety of considerations based on which invasive plant managers make complex decisions about when, where, and how to intervene. Their widespread pragmatic acceptance of small, situated gains (as well as losses) combines with impressive long-term commitments to the task of invasives management. We suggest that the actual practice of weed management challenges those academic perspectives that still aspire to attain pristine nature.

Farmer-Managed Natural Regeneration Enhances Rural Livelihoods in Dryland West Africa

Declining agricultural productivity, land clearance and climate change are compounding the vulnerability of already marginal rural populations in West Africa. 'Farmer-Managed Natural Regeneration' (FMNR) is an approach to arable land restoration and reforestation that seeks to reconcile sustained food production, conservation of soils and protection of biodiversity. It involves selecting and protecting the most vigorous stems regrowing from live stumps of felled trees, pruning off all other stems, and pollarding the chosen stems to grow into straight trunks. Despite widespread enthusiasm and application of FMNR by environmental management and development projects, to date, no research has provided a measure of the aggregate livelihood impact of community adoption of FMNR. This paper places FMNR in the context of other agroforestry initiatives, then seeks to quantify the value of livelihood outcomes of FMNR. We review published and unpublished evidence about the impacts of FMNR, and present a new case study that addresses gaps in the evidence base. The case study focuses on a FMNR project in the district of Talensi in the semi-arid Upper East Region in Ghana. The case study employs a Social Return on Investment (SROI) analysis, which identifies proxy financial values for non-economic as well as economic benefits. The results demonstrate income and agricultural benefits, but also show that asset creation, increased consumption of wild resources, health improvements and psycho-social benefits created more value in FMNR-adopting households during the period of the study than increases in income and agricultural yields.

Aortic root morphology: a paradigm for successful reconstruction.

Aortic root (AoR) components provide synchronous and precise 3D deformation of the aortic root during the cardiac cycle in order to ensure closure and opening of the three leaflets over a lifetime. Any deviation from the natural 3D morphology, such as with AoR annulus dilatation, enlarged sinuses and/or dilatation of the sinotubular junction, as in the case of ascending aortic dilatation, may result in disruption of the natural AoR function. Surgical treatment of AoR pathology has two modalities: the replacement of the aortic valve by artificial prosthesis or by preservation of the three leaflets and reconstruction of the aortic root components. Currently, there are two basic aortic root reconstruction procedures: aortic root sparing and aortic valve reimplantation techniques. Regardless of the technique used, the restoration of adequate cusp coaptation, is from a technical point of view, the most important element to consider. To achieve this, there are two requirements that need to be met: (i) the valve coaptation should be superior to the level of the aortic root base by at least 8 mm and (ii) the coaptation height per se has to be ≥5 mm. Successful restoration of the aortic root requires adequate technical skills, detailed knowledge of aortic root anatomy and topography, and also knowledge of the spatial pattern of AoR elements. Recently, there has been growing interest in aortic root reconstructive procedures as well their modifications. As such, the aim of this review is to analyse aortic root topography and 3D anatomy from a surgical point of view. The review also focuses on potential risk regions that one should be aware of before the surgical journey into the 'deep waters area' of the AoR begins.

Modifier Genes as Therapeutics: The Nuclear Hormone Receptor Rev Erb Alpha (Nr1d1) Rescues Nr2e3 Associated Retinal Disease

Nuclear hormone receptors play a major role in many important biological processes. Most nuclear hormone receptors are ubiquitously expressed and regulate processes such as metabolism, circadian function, and development. They function in these processes to maintain homeostasis through modulation of transcriptional gene networks. In this study we evaluate the effectiveness of a nuclear hormone receptor gene to modulate retinal degeneration and restore the integrity of the retina. Currently, there are no effective treatment options for retinal degenerative diseases leading to progressive and irreversible blindness. In this study we demonstrate that the nuclear hormone receptor gene Nr1d1 (Rev-Erba) rescues Nr2e3- associated retinal degeneration in the rd7 mouse, which lacks a functional Nr2e3 gene. Mutations in human NR2E3 are associated with several retinal degenerations including enhanced S cone syndrome and retinitis pigmentosa. The rd7 mouse, lacking Nr2e3, exhibits an increase in S cones and slow, progressive retinal degeneration. A traditional genetic mapping approach previously identified candidate modifier loci. Here, we demonstrate that in vivo delivery of the candidate modifier gene, Nr1d1 rescues Nr2e3 associated retinal degeneration. We observed clinical, histological, functional, and molecular restoration of the rd7 retina. Furthermore, we demonstrate that the mechanism of rescue at the molecular and functional level is through the re-regulation of key genes within the Nr2e3-directed transcriptional network. Together, these findings reveal the potency of nuclear receptors as modulators of disease and specifically of NR1D1 as a novel therapeutic for retinal degenerations.

35 años de formación en Conservación-Restauración en la Facultad de Bellas Artes de la Universidad de Barcelona

Los títulos de Grado y Máster en Conservación-Restauración en la Facultad de Bellas Artes de la Universidad de Barcelona son producto de un largo proceso, con un final susceptible aún de ser modificado y mejorado. Desde los años 30 del siglo pasado hasta nuestros días, el mundo académico y profesional ha reclamadosu existencia y permanencia en el territorio de la Educación Superior y en su máxima representante, la Universidad. La formación en Conservación-Restauración ha padecido las contradicciones y las incoherenciasde normas, decretos y leyes que, alternativamente, reivindicaban este ámbito o la hacían invisible. La celebración de los 35 años de la Facultad de Bellas Artes de la Universidad de Barcelona es unmotivo de reflexión sobre la historia de los estudios universitarios de Conservación-Restauración y sus antecedentes que intentaremos resumi r a lo largo de nuestro texto.

Valors típics de pH i DP del suport de tela en la pintura de cavallet

Ja fa varies decades que els conservadors-restauradors de paper van comenc;ar a tenir en compteel pH de les obres que tractaven, ja que es va veure que I'acidesa incidia molt directament en comde rapid I'objecte es debilitava mecimicament. De fet, trobem tant aviat com el 1936, una patenten registrada per OJ. Schierholtz per desacidificar el paper d'empaperar parets (Porck, 1996).La tela d'un quadre, essent un teixit fet a base de fibres vegetals compastes majoritariament perceHulosa, com les fibres del paper, és lógicament també facilment degradable si I'ambient ñes acid(te un baix pH).Sorprenentment, pero, I'acidesa de la tela deis quadres, tot i que en ocasions puntuals ha estatanalitzada (Bajocchi, 2009; Young, 1999), encara no és un parametre que es miri de forma rutinariai per tant, fins recentment, no se sabia quins eren els valors de pH més típics que pot tenir unquadre.Aquest estudi és una primera recopilació sistematica d'aquest t ipus d' in formació per a partir d'aquícrear un banc de dades que vagi recollint aquest t ipus d'informació sobre el majar nombre possiblede quadres.Si I'acidesa present en la tela ens indica com de rapid es degradara aquesta en el futur, la mesura delgrau de polimerització de la tela (DP), ens indica si la tela té una al ta o baixa resistencia mecanica enel moment actual. Així doncs, aquests dos parametres ens aporten informació molt úti l sobre I'estatde conserva ció del suportoAquesta recerca pretén respondre a les preguntes de quins són els valors de pH i DP que típicamentpodem trabar en la tela deis quadres, així com analitzar la relació entre aquests dos parametres i també la relació entre la data de producció deis quadres i els valors de pH i DP.

Frontals d'altar medievals: marques d'eines a la fusta i tecnologia de construcció del suport

Els frontals d'altar medievals conservats a Catalunya i a la Catalunya Nord presenten unes similituds en els seus suports de fusta que permeten agrupar- los entre el ls segons els seus modelsconstructius.Per altra banda també permeten arribar a concebre com es van construir les diferents parts que els composen i amb quines eines es va treballar la fusta .L'estudi presentat es centra concretament en les marques de les eines de fuster que han quedat gravades als suports ¡ que ens permeten saber de quines eines es tractava, com s'utilitzaven ¡quinsistema es va seguir per la construcció d'aquestes estructures.Històricament no s'ha donat gens de valor als suports de fusta d'aquestes peces en comparació amb la seva capa pictòrica i, per aquest motiu, s'han portat a terme mutilacions del suport o reparacionsestructurals que no han tingut en compte la conservació dels seus elements originals. Les marques d'eina sovint han passat desapercebudes i en molts casos s'han malmès o bé s'han eliminat degut ales intervencions poc respectuoses que s'han fet al llarg del segle XX.L'objectiu de la recerca que s'està portant a terme és identificar les marques a la fusta original delssuports i poder relacionar-les amb les eines que es van utilitzar en el seu moment i fer un inventaride les marques per poder utilitzar-lo en estudis posteriors.Aquest treball s'ha desenvolupat dins la línia d'investigació del Grup de Recerca ConsolidatConservació-Restauració del Patrimoni 2014-16 - SGR 459G de la Facultat de Belles Arts, Universitatde Barcelona, anomenada Estudi tecnològic dels suports de béns culturals: materials i tècniques de producció.

Excavacions arqueologiques al jaciment d'Abasiya. Recerca, interpretació i projecte de conservació d'un conjunt arqueológic a Karima, Sudan

Remuntant el riu Nil es troba la muntanya sagrada de Dyebel Bar kal identificada pels egipcis i pels nubis com el lloc on va néixer el déu Aman. Els fa raons egipcis durant la XVIII dinastia van construir un temple dedicat a aquesta divinitat ¡ van fer d'aquesta zona (coneguda a I'antiguitat amb el nomde Napata) un dels principals centres religiosos de I'antiga Núbia. La historia compartida entre Núbiai Egipte compren segles de relacions i va culminar amb la conquesta egípcia que va suposar una egiptizació dels costums nubis. Tant es així que després d'alguns segles, els reis nubis van unificarels territoris i es van proclamar faraons de les dues terres.El jaciment arqueològic d'Abasiya que pertany a I'àrea arqueològica de Dyebel Barkal (Figura 1)es troba en la actual ciutat de Karima, a uns 400km de Khartum la capital de Sudan. És avuien dia una plac;a urbana de Karima a només700m de I'àrea arqueològica de DyebelBarkal, on simultàniament estan treballantequips arqueològics de diferents països.Abasiya compren, fins el moment, quatresectors que corresponen a I'acumulació derestes arquitectòniques. Durant 5 campanyes s'han excavat totalment els sectors A, CiD, i parcialment el Sector B, que encara esta en procés d'excavació.

Ensayos sobre nuevas metodologías para la limpieza y consolidación de documento gráfico

Desde el año 2012, en el grupo Conservació-Restauració del Patrimoni de la Facultat de Belles Arts, Universitat de Barcelona (Grup de Recerca Consolidat 2014- 16 SGR 459G reconocido porla Generalitat de Catalunya), se está desa rrollando un proyecto de investigación sobre el uso de nuevos procedimientos de limpieza mecánica y consolidación de documento gráfico mediante fibrasde celulosa. La limpieza mecánica más extendida en documento gráfico se realiza con gomas. El procedimiento, apesar de habitual, comporta riesgos potenciales para el soporte y para los elementos sustentados albasarse en mecanismos de fricción y/o abrasión que pueden ultrapasar la suciedad. Así, modificaciónde textura y/o brillo (Pearlstein et al., 1982; Sterlini, 1995), cambios en las propiedades físicas(James & Cohn, 1997; Mclnnis, 1980) y alteraciones químicas y/o mecánicas a largo plazo (DaudinSchotteet al., 2010; Moffatt & Laver, 1981; Moy, 2007; Silverman & Irwin, 2009) son los riesgos habitualmente referidos en la literatura. Para minimizar estos inconvenientes y como posible alternativa, se está eva luando la limpieza conmicroproyección de fibras de celulosa como alternativa a las gomas. Una de las principales ventajasprincipales de este procedimiento radica en el hecho de que el agente de limpieza es altamente compatible con la obra ya que tiene una composición muy similar. Por lo tanto, su empleo podríareducir la posibilidad de afectar negativamente la estabilidad química de la pieza a corto o largo plazo.Hasta el momento se han realizado ensayos comparativos entre gomas y microproyección para la limpieza de grabados calcográficos con resultados satisfactorios en eficacia y preservación de la obra a corto y medio plazo (Iglesias-Campos et al., 2014a; Iglesias-Campos & Ruiz-Recasens, 2014 enprensa; Iglesias-Campos, et al., 2014 en prensa). Paralelamente se realizan ensayos de envejecimiento artificial con los que comparar los posibles efectos en el tiempo entre ambas técnicas.

La conservació-restauració en el préstec de Béns Culturals per a exposicions temporals. Recursos per sistematitzar la documentació i garantir les millors condicions per als Béns Culturals en trànsit

Com a resultat de les práctiques realitzades al Museu Nacional d'Art de Catalunya (MNAC), entrenovembre de 2010 i febrer de 2011, emmarcades dins del Practicum del Màster de Direcció de Projectes de Conservació Restauració (Facultat de Belles Arts, Universitat Barcelona) vaig entraren contacte amb l'activitat del préstec d'obres d'art per a exposicions temporals. L'interès que em va suscitar, juntament amb el desconeixement que tenia en la matèria, em van portar a dedicarel Treball Final de Master a la recerca deis diferents aspectes que envolten el préstec de Béns Culturals en exposicions temporals, començant per una visió més global i acabant de centrar laproposta en l'àmbit de la conservació-restauració (i especialment en l'activitat documental que requereix).El treball pretén demostrar que la sistematització d'aquesta documentació és una eina bàsica per a un bon desenvolupament del procés de préstec, i ho fa fixant-se especialment en la documentació que depen de l'Àrea de Conservació-Restauració que, al cap i a la fi, és la documentació que hade permetre neutralitzar els riscos que pot comportar el préstec per a la integritat de les obres en trànsit...