2,243 publications from this institution
Aluminum salts are widely used as the active antiperspirant in underarm cosmetic. Experimental observations indicate that its long term application may correlate with breast cancer development and progression. This action is proposed to be attributed, among others, to aluminum possible estrogen-like activities. In this study we showed that aluminum, in the form of aluminum chlorohydrate (ACH), caused increase in estrogen receptor alpha (ERα) protein levels, in ERα-positive MCF-7 cells. This effect was accompanied by moderate activation of Estrogen Response Elements (ERE)-driven reporter gene expression and 20%-50% increase in certain estrogen responsive, ERE-independent genes expression. Genes affected were ERα, p53, cyclin D1, and c-fos, crucial regulators of breast cancer development and progression. ACH-induced genes expression was eliminated in the presence of the estrogen antagonist: ICI 182780, in MCF-7 cells, whereas it was not observed in ERα-negative MDA-MB-231 breast cancer cells, indicating aluminum interference with estrogen signaling. Moreover, ACH caused increase in the perinuclear localization of estrogen receptor alpha in MCF-7 breast cancer cells and increase in the mitochondrial Bcl-2 protein, possibly affecting receptors-mediated mitochondrial actions and mitochondrial-dependent apoptosis. ACH-induced perinuclear localization of estrogen receptor beta was also observed in MDA-MB-231. Our findings indicate that aluminum actions on estrogen receptors protein level and subcellular localization possibly affect receptors-mediated actions and thus, aluminum interference with estrogen signaling.
This work is an extensive experimental study on the corrosion behavior of reinforced cementitious mortars containing industrial byproducts and waste materials. In particular, calcareous (C-class) fly ashes, iron mill scale and Electrolytic Manganese Dioxide (E.M.D.) waste were used as additives in mortars production. The abovementioned materials were used without any prior treatment or management and replaced the cement in concrete mixing by 10% wt. of cement weight. For the experimental set-up, reinforced mortars were prepared and exposed to coastal area for 12 months, while some of them were remained in a salt spray cabin for 60 days. The corrosion monitoring was performed by electrochemical and mass loss measurements, while chloride content, porosity, carbonation and mineralogy of mortars were also estimated. The results indicate, that there is a development in durability and chloride penetration resistance of composites comparing with the conventional mortars at late ages. At the same time, it was also observed that their chemical composition and fineness, control the diffusion of CO2 into the pore system and lead to increased carbonation of composite mortars. The challenge of this work is the production of eco-friendly composites with high chloride and carbon dioxide penetration resistance.
The risk and losses associated with the wind-induced failure of existing steel lattice telecommunication towers are assessed for a number of upgrade/replace/redesign schemes. Specifically, a performance-based wind engineering framework is employed for assessing a typical tower topology used by EU telecommunication network operators over four different cases: a conventional design, its corroded version after 60 years, a strengthened version of the corroded tower by applying fibre-reinforced polymer plates, and a redesign with high-strength steel. Multiple potential sites of installation were considered throughout coastal and mainland Greece, comprising two different groups of design wind speed. Mischaracterization of the site-specific wind distribution is by far the most important risk factor, with corrosion coming right behind. Still, selecting a rehabilitation approach does not depend only on site and tower characteristics, but also on the projected direct and indirect losses. By considering service to different populations, even after 60 years of corrosion, the “Do Nothing” approach may still be competitive when serving few residents and for short projected lifetime, while an upgrade is considered optimal for larger towns, or wherever higher revenue is on the line.
This chapter addresses the dynamic response of single-degree-of-freedom (SDOF) oscillators in the linear elastic domain, with emphasis on ground-induced excitation. It develops the equation of motion, discusses solution approaches and presents the representation of response using pseudo-acceleration, velocity, and displacement spectra. The equations governing structural dynamics are easily established based on Newton's first two laws of motion. The momentum of a body is a vector quantity given by the product of mass and velocity. Resonance is the tendency of a system to oscillate with large peak amplitude under forced vibration at particular frequencies, known as the system's resonant frequencies. Earthquake ground motion is conveniently defined by acceleration records obtained in three orthogonal directions from a seismograph. The time derivative of the relative displacement time history is the relative velocity time history; its time derivative is the relative acceleration time history.
Long non-coding RNAs (lncRNAs) play a key role in regulating gene expression, influencing various cellular pathways by interacting with transcription factors, other RNA molecules like miRNAs, and DNA. In this study, we focused on the role of lncRNAs related to nuclear receptors (NRs), which are a family of transcription factors activated by ligands. NRs are involved in vital biological processes such as metabolism, immune response, reproduction, and development. We discovered six novel sequence motifs within lncRNAs that respond to multiple NRs suggesting they are not specific to a single receptor. One of the motifs, was complementary to miRNA hsa-miR-1908-3p, suggesting that lncRNAs containing this motif may function as miRNA sponges, regulating the expression of about 487 target mRNAs. The motifs were also found in key regulatory regions of the human genome, particularly on chromosome 19, including in Adeno-associated virus integration site 1 (AAVS1), a region with a high regulatory role in gene expression. Additionally, an evolutionary analysis was conducted revealing that these motifs are highly conserved across species, including Mus musculus, Euglena gracilis, and Saccharomyces cerevisiae, indicating their ancient origins. Based on these results, we propose that these motifs may represent ancestral binding sites for nuclear receptor precursors, and may act as backup mechanisms in modern organisms, ensuring the functional versatility and evolutionary conservation of NR-mediated gene regulation.
