Towards the development of antioxidant cerium oxide nanoparticles for biomedical applications: Controlling the properties by tuning synthesis conditions

In this work CeO2 nanoparticles (CeO2-NPs) were synthesized through the thermal de-composition of Ce(NO3)3·6H2O, using as capping agents either octylamine or oleylamine, to evaluate the effect of alkyl chain length, an issue at 150 °C, in the case of octylamine and at 150 and 250 °C, in the case of oleylamine, to evaluate the effect of the temperature on NPs properties. All the nanoparticles were extensively characterized by a multidisciplinary approach, such as wide-angle X-ray diffraction, transmission electron microscopy, dynamic light scattering, UV-Vis, fluorescence, Raman and FTIR spectroscopies. The analysis of the experimental data shows that the capping agent nature and the synthesis temperature affect nanoparticle properties including size, morphology, aggregation and Ce3+/Ce4+ ratio. Such issues have not been discussed yet, at the best of our knowledge, in the literature. Notably, CeO2-NPs synthesized in the presence of oleylamine at 250 °C showed no tendency to aggregation and we made them water-soluble through a further coating with sodium oleate. The obtained nanoparticles show a less tendency to clustering forming stable aggregates (ranging between 14 and 22 nm) of few NPs. These were tested for biocompatibility and ROS inhibiting activity, demonstrating a remarkable antioxidant activity, against oxidative stress

Quantitative expression profiling of highly degraded RNA from formalin-fixed, paraffin-embedded breast tumor biopsies by oligonucleotide microarrays.

Microarray-based gene expression profiling is well suited for parallel quantitative analysis of large numbers of RNAs, but its application to cancer biopsies, particularly formalin-fixed, paraffin-embedded (FFPE) archived tissues, is limited by the poor quality of the RNA recovered. This represents a serious drawback, as FFPE tumor tissue banks are available with clinical and prognostic annotations, which could be exploited for molecular profiling studies, provided that reliable analytical technologies are found. We applied and evaluated here a microarray-based cDNA-mediated annealing, selection, extension and ligation (DASL) assay for analysis of 502 mRNAs in highly degraded total RNA extracted from cultured cells or FFPE breast cancer (MT) biopsies. The study included quantitative and qualitative comparison of data obtained by analysis of the same RNAs with genome-wide oligonucleotide microarrays vs DASL arrays and, by DASL, before and after extensive in vitro RNA fragmentation. The DASL-based expression profiling assay applied to RNA extracted from MCF-7 cells, before or after 24 h stimulation with a mitogenic dose of 17b-estradiol, consistently allowed to detect hormone-induced gene expression changes following extensive RNA degradation in vitro. Comparable results where obtained with tumor RNA extracted from FFPE MT biopsies (6 to 19 years old). The method proved itself sensitive, reproducible and accurate, when compared to results obtained by microarray analysis of RNA extracted from snap-frozen tissue of the same tumor

Direct regulation of microRNA biogenesis and expression by estrogen receptor beta in hormone-responsive breast cancer.

Estrogen effects on mammary epithelial and breast cancer (BC) cells are mediated by the nuclear receptors ERα and ERβ, transcription factors that display functional antagonism with each other, with ERβ acting as oncosuppressor and interfering with the effects of ERα on cell proliferation, tumor promotion and progression. Indeed, hormone-responsive, ERα+ BC cells often lack ERβ, which when present associates with a less aggressive clinical phenotype of the disease. Recent evidences point to a significant role of microRNAs (miRNAs) in BC, where specific miRNA expression profiles associate with distinct clinical and biological phenotypes of the lesion. Considering the possibility that ERβ might influence BC cell behavior via miRNAs, we compared miRNome expression in ERβ+ vs ERβ- hormone-responsive BC cells and found a widespread effect of this ER subtype on the expression pattern of these non-coding RNAs. More importantly, the expression pattern of 67 miRNAs, including 10 regulated by ERβ in BC cells, clearly distinguishes ERβ+, node-negative, from ERβ-, metastatic, mammary tumors. Molecular dissection of miRNA biogenesis revealed multiple mechanisms for direct regulation of this process by ERβ+ in BC cell nuclei. In particular, ERβ downregulates miR-30a by binding to two specific sites proximal to the gene and thereby inhibiting pri-miR synthesis. On the other hand, the receptor promotes miR-23b, -27b and 24-1 accumulation in the cell by binding in close proximity of the corresponding gene cluster and preventing in situ the inhibitory effects of ERα on pri-miR maturation by the p68/DDX5-Drosha microprocessor complex. These results indicate that cell autonomous regulation of miRNA expression is part of the mechanism of action of ERβ in BC cells and could contribute to establishment or maintenance of a less aggressive tumor phenotype mediated by this nuclear receptor

Mechanical and thermal properties of lightweight geopolymer composites

This research has investigated the properties of thermally insulating geopolymer composites that were prepared using waste expanded polystyrene as lightweight aggregate. The geopolymer matrix was synthetized using metakaolin and an alkaline activating solution. To improve its mechanical properties, this matrix was modified by the addition of an epoxy resin to form an organic-inorganic composite. Moreover, in order to reduce drying shrinkage marble powder was used as an inert filler. The materials obtained were characterized in terms of physico-mechanical properties, thermal performance and microstructure. The geopolymer expanded polystyrene composite have improved properties compared to Portland cement-based materials, with higher strengths and lower thermal conductivity. The research demonstrates the manufacture of sustainable lightweight thermally insulating geopolymer composites using waste expanded polystyrene

Search for gravitational wave bursts in LIGO's third science run

We report on a search for gravitational wave bursts in data from the three LIGO interferometric detectors during their third science run. The search targets subsecond bursts in the frequency range 100-1100 Hz for which no waveform model is assumed, and has a sensitivity in terms of the root-sum-square (rss) strain amplitude of hrss ~ 10^{-20} / sqrt(Hz). No gravitational wave signals were detected in the 8 days of analyzed data.Comment: 12 pages, 6 figures. Amaldi-6 conference proceedings to be published in Classical and Quantum Gravit

Search for Gravitational Waves Associated with 39 Gamma-Ray Bursts Using Data from the Second, Third, and Fourth LIGO Runs

We present the results of a search for short-duration gravitational-wave bursts associated with 39 gamma-ray bursts (GRBs) detected by gamma-ray satellite experiments during LIGO's S2, S3, and S4 science runs. The search involves calculating the crosscorrelation between two interferometer data streams surrounding the GRB trigger time. We search for associated gravitational radiation from single GRBs, and also apply statistical tests to search for a gravitational-wave signature associated with the whole sample. For the sample examined, we find no evidence for the association of gravitational radiation with GRBs, either on a single-GRB basis or on a statistical basis. Simulating gravitational-wave bursts with sine-gaussian waveforms, we set upper limits on the root-sum-square of the gravitational-wave strain amplitude of such waveforms at the times of the GRB triggers. We also demonstrate how a sample of several GRBs can be used collectively to set constraints on population models. The small number of GRBs and the significant change in sensitivity of the detectors over the three runs, however, limits the usefulness of a population study for the S2, S3, and S4 runs. Finally, we discuss prospects for the search sensitivity for the ongoing S5 run, and beyond for the next generation of detectors.Comment: 24 pages, 10 figures, 14 tables; minor changes to text and Fig. 2; accepted by Phys. Rev.