Advanced mapping of inorganic treatments on porous carbonate stones by combined synchrotron radiation high lateral µXRPD and µXRF.

Understanding the effects of consolidating inorganic mineral treatments on carbonate stones of cultural heritage, and on the nature and distribution of newly formed products within the matrix, poses a significant challenge in Heritage Science and Conservation Science. Existing analytical methods often fail to deliver spatial and compositional insights into the newly formed crystalline phases with the appropriate high lateral resolution. In this study, we explore the capabilities and limitations of synchrotron radiation (SR) micro-X-ray powder diffraction (µXRPD) mapping combined with micro-X-ray fluorescence (µXRF) to give insight into compounds formed following the application of ammonium oxalate (AmOx) and diammonium phosphate-based (DAP) solutions on porous carbonate stone. Ultimately, the integration of µXRPD mapping and µXRF analysis proved itself a powerful asset in providing precise qualitative and quantitative data on the newly formed phases, in the case of both calcium oxalates (CaOxs) and calcium phosphates (CaPs), and their complex stratigraphic distribution, thus opening a new route for applications to a more comprehensive study of inorganic treatments applied to carbonate substrates.

Advanced portable micro-SORS prototype coupled with SERDS for heritage science.

We investigate the subsurface composition of turbid materials at the micro scale by means of a portable non-invasive technique, micro-spatially offset Raman spectroscopy (micro-SORS), combined with shifted excitation Raman difference spectroscopy (SERDS). This combination enables the microscale layer analysis and allows to deal effectively with highly fluorescing samples as well as ambient light, all in a form of an in-house portable prototype device optimised for applications in heritage science. The instrument comprises ability to simultaneously collect multiple spectra by means of an optical fibre bundle, thus reducing the dead time and simplifying the ease of deployment of the technique. The performance of the synergy between micro-SORS and 785 nm SERDS dual-wavelength diode laser is demonstrated on a stratified mock-up painting samples including highly fluorescing painted layers. This instrumental approach could be ground-breaking in heritage science, due to the largely unmet need of analysing the molecular composition of subsurface of artworks non-invasively and in situ, and in the presence of fluorescent background and ambient light. Moreover, many other fields are expected to benefit from this technological advancement such as solar energy, forensic and food analytical areas.

Causes and consequences of DNA content variation in Zea / Causas y consecuencias de la variación del contenido de ADN en Zea

ABSTRACT Cytogenetic evidence indicates that Zea, which comprises maize (Z. mays ssp. mays) and its wild relatives, is an allopolyploid genus. Our research group has carried out numerous cytogenetic studies on Zea species, mainly focused on native Argentinian and Bolivian maize landraces. We found a wide inter- and intraspecific genome size variation in the genus, with mean 2C-values ranging between 4.20 and 11.36 pg. For the maize landraces studied here, it varied between 4.20 and 6.75 pg. The objectives of this work are to analyze the causes of genome size variation and to discuss their adaptive value in Zea. This variation is mainly attributed to differences in the heterochromatin located in the knobs and to the amount of interspersed DNA from retrotransposons. Polymorphisms in presence or absence of B-chromosomes (Bs) and the population frequency of Bs are also a source of genome size variation, with doses ranging between one and eight in the landraces analyzed here. Correlation analysis revealed that the percentage of heterochromatin is positively correlated with genome size. In addition, populations cultivated at higher altitudes, which are known to be precocious, have smaller genome sizes than do those growing at lower altitudes. This information, together with the positive correlation observed between the length of the vegetative cycle and the percentage of heterochromatin, led us to propose that it has an adaptive role. On the other hand, the negative relationship found between Bs and heterochromatic knobs allowed us to propose the existence of an intragenomic conflict between these elements. We hypothesize that an optimal nucleotype may have resulted from such intranuclear conflict, where genome adjustments led to a suitable length of the vegetative cycle for maize landraces growing across altitudinal clines.

RESUMEN La evidencia citogenética indica que el género Zea, el maíz (Z. mays ssp. mays) y sus parientes silvestres, posee un origen alopoliploide. Nuestro grupo de investigación ha realizado numerosos estudios en especies de Zea, principalmente en maíces nativos de Argentina y Bolivia. En este género, hallamos una amplia variación inter e intraespecífica en el tamaño del genoma, con valores 2C medios que oscilan entre 4,20 y 11,36 pg. El valor 2C medio de los maíces nativos estudiados varió entre 4,20 y 6,75 pg. Los objetivos de este trabajo son analizar las causas de la variación del tamaño del genoma en Zea y discutir su valor adaptativo. Esta variación se atribuye principalmente a las diferencias en la heterocromatina de los knobs y en la cantidad de ADN intercalado de los retrotransposones. Otras fuentes de variación son los polimorfismos para presencia/ausencia de cromosomas B (Bs) y para la frecuencia poblacional de Bs en las razas analizadas, con dosis que oscilan entre uno y ocho Bs. El porcentaje de heterocromatina se correlaciona positivamente con el tamaño del genoma. Las poblaciones cultivadas en altitudes altas, que son precoces, tienen tamaños de genoma más pequeños que las que crecen en bajas altitudes. Esta información, junto con la correlación positiva observada entre la duración del ciclo vegetativo y el porcentaje de heterocromatina, nos llevó a proponer el rol adaptativo de la heterocromatina. Por otro lado, la relación negativa encontrada entre Bs y knobs heterocromáticos nos permitió proponer la existencia de un conflicto intragenómico entre estos elementos. Hipotetizamos que de este conflicto intranuclear habría resultado el nucleotipo óptimo, donde ajustes genómicos condujeron a una duración adecuada del ciclo vegetativo en las razas de maíz que crecen a lo largo de clines altitudinales.

Non-invasive characterisation of molecular diffusion of agent into turbid matrix using micro-SORS.

This study proposes a non-invasive analytical method to study the molecular diffusion of a chemical agent into a turbid matrix with an emerging analytical technique, micro-Spatially Offset Raman Spectroscopy (micro-SORS). Here, the micro-SORS concept has been extended from the analysis of chemically distinct stratified layers to the studies and monitoring of the absorption and diffusion processes, addressing a key analytical need in a number of areas including polymer, pharmaceutical, forensic and biomedical sciences. In Cultural Heritage the knowledge of the penetration depth of a polymer used to consolidate or to protect an object, or the absorption depth of solvents used during a cleaning procedure is crucial for the performance evaluation of restoration methods and their safety towards the work of art. To date the most common protocol for obtaining this type of information comprises the application of stratigraphical analysis on cross-sections prepared after taking a small amount of sample from the work of art. This approach is destructive and may lack of statistical meaning, since the analytical information is limited to the micro area of sampling. To overcome these drawbacks, in this study micro-SORS was successfully used, for the first time, to non-invasively characterise the penetration of a polymer and of a viscous solvent into a gypsum substrate, permitting the reconstruction of the diffusion trends of the products into the matrix and the evaluation of their performances.

Micro-scale spatially offset Raman spectroscopy for non-invasive subsurface analysis of turbid materials.

This article reviews a very recent field of noninvasive analysis of turbid media using micro-scale Spatially Offset Raman Spectroscopy - micro-SORS. The technique combines conventional SORS with microscopy concepts and represents a new imaging modality in Raman microscopy. Micro-SORS facilitates analytical capability for investigating non-destructively the chemical composition of subsurface, micrometer-scale-thick diffusely scattering layers at depths more than an order of magnitude larger than those accessible with the depth resolving power of conventional confocal Raman microscopy. Potential application areas include nondestructive subsurface analysis of painted layers in cultural heritage, characterization of stratified polymer systems, analysis of layered biological samples or forensic analysis. The article discusses the basic principles of the technique, its variants and outlines emerging applications in this rapidly evolving field.

Comparison of key modalities of micro-scale spatially offset Raman spectroscopy.

We compare several basic embodiments of a recently proposed and demonstrated micrometer-scale Spatially Offset Raman Spectroscopy (micro-SORS). Micro-SORS is a recently introduced analytical method for noninvasive characterisation of the chemical composition of subsurface, micrometre-scale-thick diffusely scattering layers at depths beyond the reach of conventional confocal Raman microscopy. The technique is applicable, for example, in nondestructive subsurface analysis of highly scattering stratified matrices such as painted layers in cultural heritage or in noninvasive analysis of stratified polymer systems or biological samples. Using Monte Carlo simulations, we analysed two defocusing variants of micro-SORS and a variant involving a full separation of illumination and collection zones on the sample surface. Both the penetration depth into the sample and relative enhancement of sublayer Raman signals were studied as a function of layer thickness and type of technique and their parameters. The model predicts that the most effective method by far is the variant with fully spatially separated illumination and collection zones. On the other hand, the defocusing micro-SORS, where both the laser and Raman collection zones are defocussed and overlapped, yielded the lowest performance although its key benefit lies in its simplicity as the concept can be practiced on existing conventional Raman microscopes without any modifications. A basic experimental verification of the theoretical findings contrasting two extreme modalities, the fully separated micro-SORS variant with the defocusing one, is also presented.

Terracotta polychrome sculptures examined before and after their conservation work: contributions from non-invasive in situ analytical techniques.

The potential of non-invasive in situ analytical techniques such as portable Raman, portable X-ray fluorescence, portable optical microscope and fibre optics reflectance spectroscopy has been shown studying painted layers of Renaissance terracotta polychrome sculptures belonging to the statuary of Santo Sepolcro Church in Milan. The results obtained allowed pointing out the contribution of these techniques to the compositional diagnostic, providing complete information, in some cases, better than micro-destructive techniques, on the kind of pigments used on the external painted layers. Moreover, a comparison with the results obtained before the last conservation work (2009) with micro-destructive techniques allowed ascertaining the removal of the external painted layers during the conservation operations.

Atypical coloration of plaster in renaissance frescoes.

The Baptistery of Castiglione Olona (Varese, Italy), frescoed by Masolino da Panicale at the beginning of the 14th Century, is currently under restoration. On this occasion its state of preservation was investigated, in order to plan a correct intervention. During the sampling, an interesting phenomenon was pointed out, i.e. a wide rose coloration on the plasters of the interior northern and western walls. In order to clarify the nature of the alteration, a sampling was undertaken both for a chemical-mineralogical characterization of plasters (XRD, SEM-EDX, FTIR) and to detect the presence of biodeteriogens.

Evaluation of barium hydroxide treatment efficacy on a dolomitic marble.

The Arch of Peace, by Luigi Cagnola, is one of the most famous neoclassical monuments in Milan. It has been subjected to conservative intervention in 1998. In the present paper the efficacy of the consolidation by means of barium hydroxide has been evaluated. The stone material showed severe degradation phenomena as: erosion, pulverisation, exfoliation. The analytical data acquired through X-ray diffraction (XRD), infrared spectrophotometry (FTIR) and scanning electron microscopy (SEM-EDX), allowed to compare the conditions of stone before and after the treatment with barium hydroxide. The presence of barium has been put in evidence mainly on the surface as barium sulphate, whereas barium is only sporadically present within the thickness of the decayed material. The treatment was judged not satisfying and its inefficacy is, most probably, due to a not suitable cleaning procedure carried out before the consolidation.

Postoperative bleeding after coronary revascularization. Comparison between tranexamic acid and epsilon-aminocaproic acid.

BACKGROUND: Microvascular bleeding after Cardiopulmonary bypass (CPB) is mainly due to consumption of clotting factors, platelets damage, and hyperfibrinolysis. Aprotinin, the only antifibrinolytic drug effective in preserving platelets, is no longer available; an alternative regimen based on pure antifibrinolytic drugs has been proposed, since hyperfibrinolysis is known to contribute both to clot lysis and platelet dysfunction. In this study the efficacy of two antifibrinolytic drugs, Tranexamic acid (TA) and epsilon-aminocaproic acid (EACA), was tested in patients undergoing cardiopulmonary bypass (CPB), for primary myocardial revascularization. METHODS: Forty-eight consecutive patients were randomized to receive prophylactically equipotent doses of EACA (group A) or TA (Group B). Platelet count, prothrombin time, fibrin digestion products, blood loss and transfusion requirements recorded after 6 and 24 hours from the end of surgery were compared. RESULTS: The two groups were comparable for length of CPB and numbers of grafts; no significant difference was observed in the coagulation parameters considered. Blood losses were less in group B (TA) than in group A (EACA), both at 6 and 24 hours after surgery; homologous blood transfused was also less in group B, but no difference was statistically significant. No adverse effect was observed. CONCLUSIONS: In coronary patients, TA and EACA exhibit the same effects on blood loss and requirements after CPB; either drug can be safely used in cardiac surgery.

[Cutaneo-visceral disseminated flat angioma, glaucoma, hypospadias and testicular ectopy]. / Angioma plano diseminado cutáneo visceral, glaucoma, hipospadias y ectopia testicular.

A case of associated disease in a child is described. It consisted of a disseminated capillary naevus with a vascular malformation in the gastrointestinal tract, bilateral congenital glaucoma, hypospadias, and bilateral ectopic testicles.