Estrogen mediated-activation of miR-191/425 cluster modulates tumorigenicity of breast cancer cells depending on estrogen receptor status.

MicroRNAs (miRNAs), single-stranded non-coding RNAs, influence myriad biological processes that can contribute to cancer. Although tumor-suppressive and oncogenic functions have been characterized for some miRNAs, the majority of microRNAs have not been investigated for their ability to promote and modulate tumorigenesis. Here, we established that the miR-191/425 cluster is transcriptionally dependent on the host gene, DALRD3, and that the hormone 17β-estradiol (estrogen or E2) controls expression of both miR-191/425 and DALRD3. MiR-191/425 locus characterization revealed that the recruitment of estrogen receptor α (ERα) to the regulatory region of the miR-191/425-DALRD3 unit resulted in the accumulation of miR-191 and miR-425 and subsequent decrease in DALRD3 expression levels. We demonstrated that miR-191 protects ERα positive breast cancer cells from hormone starvation-induced apoptosis through the suppression of tumor-suppressor EGR1. Furthermore, enforced expression of the miR-191/425 cluster in aggressive breast cancer cells altered global gene expression profiles and enabled us to identify important tumor promoting genes, including SATB1, CCND2, and FSCN1, as targets of miR-191 and miR-425. Finally, in vitro and in vivo experiments demonstrated that miR-191 and miR-425 reduced proliferation, impaired tumorigenesis and metastasis, and increased expression of epithelial markers in aggressive breast cancer cells. Our data provide compelling evidence for the transcriptional regulation of the miR-191/425 cluster and for its context-specific biological determinants in breast cancers. Importantly, we demonstrated that the miR-191/425 cluster, by reducing the expression of an extensive network of genes, has a fundamental impact on cancer initiation and progression of breast cancer cells

The Kaiser effect in wood \u2013 does historic wood have a stress memory?

Acoustic emission (AE) signals generated under loading provide valuable information about structural changes undergoing in a material. For materials which have ability to remember load history, the AE activity is observed only above a load level that has been previously exerted on the same material. This ability to memorize the highest level of stress which the material has experienced in the past is known as the Kaiser effect. The persistence of the Kaiser effect in time for metals and mineral materials has been observed by many researchers. In case of organic materials such as wood, the evidence for the phenomenon is very limited. Earlier experimental evidence has shown that the Kaiser effect fades over the time for new seasoned wood. The process is accelerated by temperature and changes of moisture content in the tested material. In this article, a systematic study of the Kaiser effect in historic wood is presented. Measurements were performed in the laboratory on spruce beams from a roof timber structure of a historic palace in Northern Italy. The wood is almost 100 years old. The results clearly show that the Kaiser effect is observed even after one year between subsequent loadings. The observed long-time memory of historic wood can be explained by much higher ratio between the crystalline and amorphous phases of the material when compared to new wood, reported in the literature. The observation opens a new perspective for the determination of load history of wooden works of art and constructions, which is essential for assessing risk of their physical damage

Análise microclimática de um edifício histórico em clima temperado: limites sustentáveis para a correta conservação dos materiais

Apesar da reconhecida importância conferida ao estudo microclimático em edifícios históricos para a correta conservação de suas coleções e objetos de relevância histórica e cultural, o conhecimento acerca de seu comportamento em climas temperados é ainda reduzido. Ao longo das últimas décadas surgiram diferentes especificações focadas nas necessidades higrotérmicas dos materiais. Nesse campo, a abordagem dinâmica, baseada no microclima histórico, gerou um amplo consenso entre os especialistas, como meio de alcançar intervalos sustentáveis de temperatura e umidade relativa. Este estudo visou classificar de forma clara o microclima interior de um edifício histórico em clima temperado – Igreja de São Cristóvão, em Lisboa –, com o objetivo de verificar a qualidade microclimática para a conservação dos materiais e validar possíveis alterações. Para tal, utilizou-se um sistema de monitoramento continuo entre novembro de 2011 e agosto de 2013, com registros a cada 10 min, utilizando-se diversos sensores de temperatura e umidade relativa. O microclima foi classificado de acordo com a especificação ASHRAE – Handbook HVAC Applications, Chapter 21: Museums, galleries, archives and libraries. Constatou-se elevada estabilidade climática natural, que não justifica a implementação de sistemas de climatização

Numerical modelling of mechanical degradation of canvas paintings under desiccation

[EN] Mechanical damage in oil paintings on canvas show up as cracks and loss of original paint. Several parameters can contribute to this type of degradation. These paintings have a complex layered structure, typically composed of minimum four or more hygroscopic materials, each of which has different (non-linear) material properties and geometrical complexities. The mechanical degradation of canvas paintings occurs because each of these materials have diverse responses under fluctuating environmental conditions, especially temperature and relative humidity (RH). By examining the geometrical complexities and the non-linear material properties, this paper presents an investigation of three degradation phenomena under desiccation: (1) bulging formation around the corners, (2) crack formation in glue and ground layers, and (3) plastic deformation in the ground and oil paint layers. This on-going investigation provides further insights into the global and local stress distribution in typically constructed oil canvas paintings. This includes finite element method (FEM) and extended-FEM (XFEM) computer models at various scales, under desiccation from the initial RH of 90%, and 50¿10%. The models consist of four to five different materials, namely lead white oil paint, red iron oxide oil paint, rabbit skin glue, linen canvas, and a spruce stretcher. The models were constructed using several combinations of materials to conduct parametric studies on the effects of glue shrinkage in paintings due to desiccation, and changing the mechanical properties of the ground layers. The relevant geometrical and mechanical properties with respect to the stress relaxation conditions are discussed in detail. The simulation results of the full-scale models show that the shrinkage of glue lowers the level of induced tension stresses in the paint layers in the central area of the painting due to the inward bowing of the stretcher. The inward deformation of the stretcher can be 4.5 times as large in a painting with a glue layer as in one without. This indicates the difficulty in forming cracks near the center of paintings purely by desiccation; however, in close-up cross-section model, cracks of 20 ¿m in length could still be observed in the ground exposed to an extreme RH change of 90% to 10%. The analysis of cross-section models with the full geometrical complexity for the corners showed that multiple cracks are likely to form in ground and paint layers in the corners when desiccated by 40%; RH 50¿10%. Furthermore, in extreme cases with stiffer ground/paint such as zinc white, cracks can form from smaller drop in RH; RH 50% to 35%. Such cracks are form in the ground layers, and therefore, are not initially visible as they are positioned below the uncracked paint layer. This result can be the possible explanation for cracks in the ground, which are initially invisible with the naked eye, but can be revealed with X-radiographs. The results support the hypothesis that fluctuations in relative humidity can cause hidden cracks in the lower layers, which can eventually propagate further into the upper-lying paint layers of paintings. The cracks typically form when the desiccation reaches a 40% drop, but in cases of brittle materials the drop causing cracks can be lower. The actual RH drop causing cracks depends on the specific material composition.This research was funded by the European Union's Horizon 2020 research and innovation program under grant agreement No. 814624. Lukasz Bratasz's work was financed by also the Polish National Agency for Academic Exchange, project Polish Returns [grant PPN/PPO/2018/1/00004/U/00001].Lee, D.; Kim, N.; Scharff, M.; Nielsen, A.; Mecklenburg, M.; Fuster-López, L.; Bratasz, L.... (2022). Numerical modelling of mechanical degradation of canvas paintings under desiccation. Heritage Science. 10(1):1-13. https://doi.org/10.1186/s40494-022-00763-w11310