1,721,934 research outputs found
Experimental status of 7Be production and destruction at astrophysical relevant energies
Get PDFThe production and destruction of 7Be plays a significant role in the Big Bang Nucleosynthesis as well as in the framework of the solar neutrino. The 3He(α, γ)7Be reaction cross sections has been measured several times in the last decades, but the precision achieved on reaction rate determinations at the relevant astrophysical energies is not yet satisfactory. The experimental status of this reaction will be critically reviewed, and the theoretical descriptions available will be discussed
A Regulatory “miRcircuitry” Involving miR221&222 and ERα Determines ERα Status of Breast Cancer Cells
No full textEstrogen Receptor α (ERα) is the most important diagnostic and prognostic factor in breast
cancer. Several lines of evidence have suggested that ERα-negative breast tumors, highly
aggressive and non-responsive to hormonal therapy, arise from ERα-positive precursors
through different molecular pathways. microRNAs (miRs) are small non-coding RNAs that
regulate gene expression at post-transcriptional level and are aberrantly expressed in breast
cancer. We hypothesized that microRNAs may have a pivotal role in ERα suppression and
ERα-negative tumors formation. MicroRNAs microarray, quantitative real-time PCR,
immunohistochemistry and in-situ hybridization analyses of breast cancer cell lines and
primary tumors with different ERα-status indicated that miR221&222 are exclusively
expressed in ERα-negative breast tumors. Overexpression of both microRNAs in ERα-
positive cell lines strongly reduces the levels of ERα protein and, using luciferase reporter
assays, we clearly demonstrated that ERα is a bona fide target of miR221&222. Gene
expression profiles were analyzed after miR221 or miR222 over-expression in ERα-positive
cells: up-regulation of anti-apoptotic genes, growth factors and down modulation of adhesion
molecules indicated that miR221&222 may not only increase the ability to suppress
apoptosis and accelerate tumor formation but also promote remodeling of the tumor
microenvironment and escape of tumor cells through the basement membrane, all
characteristics of ERα-negative cells. To gain more insights into the inverse correlation
between miR221&222 and ERα in breast cancer, by computational analyses and reporter
assay, we characterized the transcriptional unit of miR221&222. We identified several
estrogen-responsive elements (ERE) at the genomic locus of miR221&222 and, by using
different approaches, we demonstrated that ERα suppresses miR221&222 expression.
Overexpression of exogenous or endogenous ERα protein in ERα-negative cells markedly
repressed miR221&222; conversely, knockdown of ERα in ERα-positive cells increased
their expression. Finally, chromatin immunoprecipitation (ChIP) on ERα-positive cells
showed that ligand-bound ERα and its co-repressor proteins, NcoR and SMRT, were highly
enriched at miR221&222 genomic locus. Notably, ChIP experiments after estradiol (E2)
stimulation or ERα-knockdown revealed that ERα recruitment is essential for the corepressor
enrichment and miR221&222 repression. These findings suggest that the negative regulatory loop involving miR221&222 and ERα may confer proliferative advantage and
migratory activity to breast cancer cells and promote the transition from ERα-positive to
ERα-negative tumors. Therefore, the elucidation of this pathway could be an important step
in the development of the next generation of breast cancer therapeutics agents that may
prevent hormone-resistance that frequently occurs during treatment
Older People and Smartphone Practices in Everyday Life: An Inquire on Digital Sociality of Italian Older Users
No full textThis paper investigates the use of smartphone in older people everyday life and it is based on an empirical research involving 30 Italian smartphone users aged 62–76. The research drawn on the analysis of 75,089 log data, 3 collective and 20 face-to-face interviews. The paper describes the digital practices through which older users use smartphone to construct social relations within their everyday life as well as elaborate their own media ideologies. The article’s findings show that participants use smartphone for a limited amount of time and mainly to access WhatsApp. The smartphone is mainly used as an organizational device for activating momentary social connections to accomplish practical tasks. The ludic use of smartphone is rarely carried out. Specifically, we observed that through the smartphone, participants put into existence three kinds of “social spaces”: 1) a working space (with peers); 2) a space of augmented co-presences (with children); 3) a space of mutual digital education (grandchildren). In conclusion we argue that the forms of sociality participants put into existence through smartphone are marked by degrees of network privatism. While the media ideology they articulate around their everyday use of smartphone can be conceived as social media phobic
Measurement of the 3He(α, γ)7Be cross section with the recoil separator ERNA
No full textA novel approach for the measurement of the 3He(α, γ)7Be reaction cross section uses the European Recoil separator for Nuclear Astrophysics to directly detect the 7Be ions produced in the reaction and, additionally, the coincident capture γ-rays. The experiment is presented
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