Nanoelectromechanical coupling in fullerene peapods probed via resonant electrical transport experiments

Fullerene peapods, that is carbon nanotubes encapsulating fullerene molecules, can offer enhanced functionality with respect to empty nanotubes. However, the present incomplete understanding of how a nanotube is affected by entrapped fullerenes is an obstacle for peapods to reach their full potential in nanoscale electronic applications. Here, we investigate the effect of C60 fullerenes on electron transport via peapod quantum dots. Compared to empty nanotubes, we find an abnormal temperature dependence of Coulomb blockade oscillations, indicating the presence of a nanoelectromechanical coupling between electronic states of the nanotube and mechanical vibrations of the fullerenes. This provides a method to detect the C60 presence and to probe the interplay between electrical and mechanical excitations in peapods, which thus emerge as a new class of nanoelectromechanical systems.Comment: 7 pages, 3 figures. Published in Nature Communications. Free online access to the published version until Sept 30th, 2010, see http://www.nature.com/ncomms/journal/v1/n4/abs/ncomms1034.htm

Defending the genome from the enemy within:mechanisms of retrotransposon suppression in the mouse germline

The viability of any species requires that the genome is kept stable as it is transmitted from generation to generation by the germ cells. One of the challenges to transgenerational genome stability is the potential mutagenic activity of transposable genetic elements, particularly retrotransposons. There are many different types of retrotransposon in mammalian genomes, and these target different points in germline development to amplify and integrate into new genomic locations. Germ cells, and their pluripotent developmental precursors, have evolved a variety of genome defence mechanisms that suppress retrotransposon activity and maintain genome stability across the generations. Here, we review recent advances in understanding how retrotransposon activity is suppressed in the mammalian germline, how genes involved in germline genome defence mechanisms are regulated, and the consequences of mutating these genome defence genes for the developing germline

Long-Term Effects of the Periconception Period on Embryo Epigenetic Profile and Phenotype: The Role of Stress and How This Effect Is Mediated

Stress represents an unavoidable aspect of human life, and pathologies associated with dysregulation of stress mechanisms - particularly psychiatric disorders - represent a significant global health problem. While it has long been observed that levels of stress experienced in the periconception period may greatly affect the offspring's risk of psychiatric disorders, the mechanisms underlying these associations are not yet comprehensively understood. In order to address this question, this chapter will take a 'top-down' approach, by first defining stress and associated concepts, before exploring the mechanistic basis of the stress response in the form of the hypothalamic-pituitary-adrenal (HPA) axis, and how dysregulation of the HPA axis can impede our mental and physical health, primarily via imbalances in glucocorticoids (GCs) and their corresponding receptors (GRs) in the brain. The current extent of knowledge pertaining to the impact of stress on developmental programming and epigenetic inheritance is then extensively discussed, including the role of chromatin remodelling associated with specific HPA axis-related genes and the possible role of regulatory RNAs as messengers of environmental stress both in the intrauterine environment and across the germ line. Furthering our understanding of the role of stress on embryonic development is crucial if we are to increase our predictive power of disease risk and devise-effective treatments and intervention strategies

Applicazione del metodo Failure Mode, Effects and Criticality Analysis (FMECA) in Tomoterapia: confronto tra approccio classico e metodologia fuzzy

Le analisi di incidenti nel settore radioterapico hanno evidenziato ed evidenziano la necessità di incrementare le misure di garanzia della qualità (QA) a partire dall’identificazione di guasti/errori considerati rari, ma con conseguenze molto severe. In questo ambito, l’applicazione della tecnica Failure Mode, Effects And Criticality Analysis (FMECA) per la classificazione di eventi critici ha riscontrato un grande interesse. Lo scopo del presente lavoro è la comparazione dei risultati ottenuti nell’applicazione di due diverse metodologie FMECA (classica e fuzzy) per la valutazione dei rischi su pazienti sottoposti a trattamenti eseguiti con tomoterapia elicoidale. Il confronto è stato effettuato utilizzando un’analisi di rischio svolta dai ricercatori del Dipartimento di Fisica, Università degli Studi di Milano, in collaborazione con fisici medici e radioterapisti dell’IRCCS Ospedale San Raffaele di Milano, per le fasi di “pianificazione del trattamento” ed “esecuzione del trattamento”. I modi di guasto sono stati classificati utilizzando l’indice di rischio, Risk Priority Number (RPN). Lo studio ha consentito di evidenziare differenze e similitudini della classificazione dei guasti/errori che è necessaria per un efficace programma di miglioramento delle condizioni di sicurezza già raggiunte nella attuale pratica clinica

Antitumor activity of interferon-β1a in hormone refractory prostate cancer with neuroendocrine differentiation.

PURPOSE: Type I interferons (IFN-α and IFN-β) are a class of cytokines that exert several biological activities, such as modulation of cell proliferation and differentiation and of the immune system. Although these cytokines interact with a common receptor complex, IFN-β showed a more potent antitumor activity than IFN-α in several tumor models. New recombinant human IFN-β products, such as IFN-β1a and IFN-β1b, have been produced in order to improve the stability and bioavailability of natural IFN-β. In this report, we analyzed the effects of recombinant IFN-β1a on the cell proliferation of two human androgen-resistant prostate cancer cell lines with neuroendocrine differentiation (DU-145, PC-3) and related mechanisms of action. METHODS: The effects of IFN-β1a on the cell growth proliferation, cell cycle, and apoptosis have been evaluated in DU-145 and PC-3 cells through MTT assay, DNA flow cytometry with propidium iodide, and Annexin V-FITC/propidium iodide staining, respectively. Moreover, the expression of neuron-specific enolase (NSE), cleaved caspase-3, caspase-8, and PARP was evaluated through Western blotting. RESULTS: IFN-β1a showed a significant anti-proliferative activity in both androgen-resistant cell lines. This effect was related to cell cycle perturbation and induction in apoptosis, as shown by flow cytometric analysis, the activation of caspase-3 and caspase-8 and PARP cleavage during incubation with IFN-β1a. Moreover, this cytokine reduced the expression of NSE in both cell lines. CONCLUSIONS: Recombinant IFN-β1a (Rebif) showed a potent in vitro anti-proliferative activity in androgen-resistant prostate cancer cells, and it could represent a promising tool for the treatment of this tumor

Invited presentation at the 15th Irish Environmental Researchers Colloquium (Environ05)

The compressibility of some fine and coarse fibrous peats was studied in the laboratory using the oedometer apparatus. Load tests were also conducted on pairs of identical test specimens prepared such that the axis of one specimen was orthogonal to, and the axis of the second specimen parallel to the cross-anisotropic fabric in order to assess the level of compressibility-anisotropy due to the preferential horizontal orientation of the constituent organic solids. The laboratory-measured values for the compression index (Cc), which is used to estimate the amounts of field settlement, were compared with the Cc values predicted using existing empirical correlations. Terzaghi and Peck?s (1967) correlation gave values in close agreement with the laboratory-measured values. An overview of a new laboratory apparatus that is currently being developed to study the reduction in the permeability of peat deposits due to surface loading, such as an embankment, is also presented. The permeability under horizontal and vertical seepage conditions are independently measured on undisturbed block samples of peat which are compressed one-dimensionally by applying increment vertical loads