An Action-Based Approach to Presence: Foundations and Methods

This chapter presents an action-based approach to presence. It starts by briefly describing the theoretical and empirical foundations of this approach, formalized into three key notions of place/space, action and mediation. In the light of these notions, some common assumptions about presence are then questioned: assuming a neat distinction between virtual and real environments, taking for granted the contours of the mediated environment and considering presence as a purely personal state. Some possible research topics opened up by adopting action as a unit of analysis are illustrated. Finally, a case study on driving as a form of mediated presence is discussed, to provocatively illustrate the flexibility of this approach as a unified framework for presence in digital and physical environment

Occurrence of proteinaceous moieties in S-and O-rich Late Tithonian kerogen (Kashpir oil Shales, Russia)

Abstract The polar fraction, isolated from the o-line pyrolysate at 400 C of a Late Tithonian, sulphur-and oxygen-rich, kerogen was examined via Raney Nickel desulphurization and TMAH thermochemolysis. Important information on this kerogen, not accessible via conventional pyrolysis, was thus obtained: (i) its structure is not simply based on alkyl skeletons cross-linked by ether and (poly)sulphide bridges, (ii) TMAH thermochemolysis aorded direct evidence of the survival of proteinaceous moieties in this 140 million years old kerogen and (iii) encapsulation within an aliphatic organic matrix was probably the main pathway reponsible for such a conspicuous preservation, also possibly favoured by the presence of numerous sulphur links.

Are biological effects of shock waves caused by free radicals?

Stone fragmentation in extracorporeal shock wave lithotripsy as well as accompanying tissue damage are attributed to cavitation. We attempted to demonstrate and localize the occurrence of cavitation in cell-free solutions and MGH-U1 cells using sensitive dyes for the detection of cavitation-generated free radicals

Recent trends and developments in pyrolysis-gas chromatography: review

Pyrolysis-gas chromatography (Py-GC) has become well established as a simple, quick and reliable analytical technique for a range of applications including the analysis of polymeric materials. Recent developments in Py-GC technology and instrumentation include laser pyrolysis and non-discriminating pyrolysis. Progress has also been made in the detection of low level polymer additives with the use of novel Py-GC devices. Furthermore, it has been predicted that future advances in separation technology such as the use of comprehensive two-dimensional gas chromatography will further enhance the analytical scope of Py-GC

Methoxy- and Acetoxy-8-oxoberbines-Synthesis, Antitumor-Activity, and Interaction with DNA

Most of the memoxy-8H-dibenzo[a,g]isoquinolin-8-ones 3a-h and their acetoxy derivatives 6a-e were synthesized by condensation of 1-oxo-1,2,3,4-tetrahydroisoquinolines 4a-c and homophthalic acid anhydrides 5a and b, ether cleavage and acetylation. These protoberberinones were tested for cytostatic activity in vitro using MDA-MB-231 mammary tumor cells and for interaction with native calf thymus DNA. Tetramethoxy-8-oxoberbine 3f shows an inhibition of cell proliferation of 87% at a concentration of 10-5 mole; its cytostatic effect does not depend on intercalation into DNA. Die meisten der Methoxy-8H-dibenzo[a,g]chinolizin-8-one 3a-h und ihre Acetoxyderjvate 6a-e wurden durch Kondensation der 1-Oxo-1,2,3,4-tetrahydroisochinoline 4a-c mit den Homophthalsäureanhydriden 5a und b, anschließende Etherspaltung und Acetylierung dargestellt. Die cytostatische Wirkung dieser Protoberberinone wurde an der MDA-MB-231-Zellinie, die DNA-Interaktion an nativer Kalbsthymus-DNA geprüft. Das Tetramethoxy- 8-oxoberbin 3f zeigt eine Hemmung der Zellproliferation von 87% bei einer Konzentration von 10-5 M, wobei die cytostatische Wirkung nicht auf eine Interkalation mit der DNA zurückzuführen ist

Redox-active and DNA-binding coordination complexes of clotrimazole

DNA interactions of anticancer mononuclear Cu2+, Co2+, Zn2+, and Ni2+ complexes with the biologically active ligand clotrimazole (clotri) are reported. To fully characterize DNA binding modes for these complexes of the formulae [M(clotri)2Cl2]·nH2O (1–4), [M(clotri)2Br2]·nH2O (5,6), [M(clotri)3NO3]NO3·nH2O (9), and [M(clotri)3(NO3)2] (10), circular dichroism (CD) and linear dichroism (LD) spectroscopy, UV melting experiments, atomic force microscopy (AFM) and ethidium bromide (EtBr) displacement methods were used. Results indicate mixed electrostatic interactions, possibly through groove binding, that result in accretion and coiling of DNA. Electrochemical studies indicate that the Cu2+ complex 9 readily reduces to the reactive-oxygen-species-generating Cu+, which oxidatively damages DNA. There is a subtle correlation between log P values, calculated electrostatic potentials, and cytotoxicity of the complexes. The extent of cell-nucleus DNA-metal adduct formation in the HeLa cervix-uterine carcinoma cell line does not necessarily correlate with cytotoxicity, indicating that the nature of DNA lesions may be crucial to activity

Luminescent detection of DNA-binding proteins

Transcription factors play a central role in cell development, differentiation and growth in biological systems due to their ability to regulate gene expression by binding to specific DNA sequences within the nucleus. The dysregulation of transcription factor signaling has been implicated in the pathogenesis of a number of cancers, developmental disorders, inflammation and autoimmunity. There is thus a high demand for convenient high-throughput methodologies able to detect sequence-specific DNA-binding proteins and monitor their DNA-binding activities. Traditional approaches for protein detection include gel mobility shift assays, DNA footprinting and enzyme-linked immunosorbent assays (ELISAs) which tend to be tedious, time-consuming, and may necessitate the use of radiographic labeling. By contrast, luminescence technologies offer the potential for rapid, sensitive and low-cost detection that are amenable to high-throughput and real-time analysis. The discoveries of molecular beacons and aptamers have spearheaded the development of new luminescent methodologies for the detection of proteins over the last decade. We survey here recent advances in the development of luminescent detection methods for DNA-binding proteins, including those based on molecular beacons, aptamer beacons, label-free techniques and exonuclease protection