525 research outputs found
The construction of Hadrian's Wall
No full textEThOS - Electronic Theses Online ServiceGBUnited Kingdo
STIMULATED EMISSION SPECTROSCOPY OF : ELECTRONIC TRANSITION MOMENT OF THE B-X SYSTEM BETWEEN 2.4-4.2 {\AA} AND HYPERFINE STRUCTURE OF
No full textL. Brewer and J. Tellinghutsen, J. Chem. Phys. 56, 3929 (1972).""Author Institution: Departments of Chemistry, Aeronautics and Astronautics Massachusetts Institute of Technology; Departments of Chemistry, Universite Claude Bernard-Lyon IGain measurements of an optically pumped laser for various B-X transitions ranging from allow determination of the electronic transition moment as a function of R-centroid. Since the gain is measured under conditions of zero light intensity the measurements are free from ambiguities due to absolute intensity, power broadening, and concentration. The electronic transition moment attains a maximum of near R-centroid = 3.2 {\AA} as predicted by Tellinghuisen and and goes to zero at large R. A stabilized single-mode laser is used to pump an laser thus preparing a different single velocity class of molecules for each hyperfine component in the upper laser level . Monitoring the laser output in the band as a function of the laser cavity length gives rise to a spectrum with linewidth of the order of the homogeneous width. This spectrum can be deconvoluted to obtain the hyperfine structure of of of iodine
Measles virus causes immunogenic cell death in human melanoma
No full textNoOncolytic viruses (OV) are promising treatments for cancer, with several currently undergoing testing in randomised clinical trials. Measles virus (MV) has not yet been tested in models of human melanoma. This study demonstrates the efficacy of MV against human melanoma. It is increasingly recognised that an essential component of therapy with OV is the recruitment of host antitumour immune responses, both innate and adaptive. MV-mediated melanoma cell death is an inflammatory process, causing the release of inflammatory cytokines including type-1 interferons and the potent danger signal HMGB1. Here, using human in vitro models, we demonstrate that MV enhances innate antitumour activity, and that MV-mediated melanoma cell death is capable of stimulating a melanoma-specific adaptive immune response
Retinitis Pigmentosa GTPase Regulator (RPGR) protein isoforms in mammalian retina:insights into X-linked Retinitis Pigmentosa and associated ciliopathies
No full textMutations in the cilia-centrosomal protein Retinitis Pigmentosa GTPase Regulator (RPGR) are a frequent cause of retinal degeneration. The RPGR gene undergoes complex alternative splicing and encodes multiple protein isoforms. To elucidate the function of major RPGR isoforms (RPGR 1-19 and RPGR ORF15), we have generated isoform-specific antibodies and examined their expression and localization in the retina. Using sucrose-gradient centrifugation, immunofluorescence and co-immunoprecipitation methods, we show that RPGR isoforms localize to distinct sub-cellular compartments in mammalian photoreceptors and associate with a number of cilia-centrosomal proteins. The RCC1-like domain of RPGR, which is present in all major RPGR isoforms, is sufficient to target it to the cilia and centrosomes in cultured cells. Our findings indicate that multiple isotypes of RPGR may perform overlapping yet somewhat distinct transport-related functions in photoreceptors
NMR STUDIES OF AROMATIC NITROGEN HETEROCYCLIC COMPOUNDS: BENZOTRIAZOLES
No full textAuthor Institution: Air Force Materials Laboratory (MAYH)The chemical shifts and coupling constants of benzotriazole, its 1-methyl and 2-methyl derivative and its anion and cation have been measured. LAOCOON III was used to iteratively refine the reported parameters. H\""{u}ckel Molecular Orbital calculations were performed in the hope of facilitating the choice of input parameters for the computation of the complex ABCD spectrum of the 1-methylbenzotriazole. No useful correlation was found between -electron densities and chemical shifts of the aromatic protons. A deuteration scheme was therefore resorted to in order to unambiguously assign the resonance frequencies of these four protons. Protonation and deprotonation experiments were also performed with benzotriazole to determine the effect of charge on the AA' BB' spectra recorded at room temperature. The NMR and MO data are compiled and compared
Biophysical characterization of gossypium synaptotagmin-1 C2B domain
No full textSynaptotagmins constitute a family of membrane-trafficking proteins that are characterized by an N-terminal transmembrane region a variable linker, and two C-terminal C2-domains. In humans, neurotransmitter release is a process highly regulated by intracellular Ca2+ levels in association with SNARE complex assembly and SYT-1 protein. In plants SYT-1 is the first synaptotagmin protein identified to participate in Ca2+ dependent repair of membranes, thus playing an important role in stress tolerance. Our long term goal is to tune the response of Gossipium SYT-1 to abiotic stress. Understanding the quaternary structure of SYT-1 C2 in plants as well as how it interacts with its cations and phospholipid is essential to further our understanding of how it exhibits its unique properties. So far, we have been successful in;
1. Developing purification protocols for Gossipium SYT-1 C2B domain, WW and AA mutants.
2. We have circular dichroism (CD) data that shows that it predominantly contains β-sheets.
3. We have probably obtained crystals in several different conditions.
4. We have confirmed the mutants through Mass Spectrometric analysis.
5. We have shown the affinity of Gossypium SYT-1 C2B WT to cations as well as to phospholipids.
6. The effect of mutations in the Ca2+ binding loop of Gossypium SYT-1 C2B was also studied.Embargo status: Restricted until 06/2162. To request the author grant access, click on the PDF link to the left
FAK deletion promotes p53-mediated induction of p21, DNA-damage responses and radio-resistance in advanced squamous cancer cells
No full textFocal adhesion kinase (FAK) is a cytoplasmic tyrosine kinase that is elevated in a variety of human cancers. While FAK is implicated in many cellular processes that are perturbed in cancer, including proliferation, actin and adhesion dynamics, polarisation and invasion, there is only some limited information regarding the role of FAK in radiation survival. We have evaluated whether FAK is a general radio-sensitising target, as has been suggested by previous reports. We used a clean genetic system in which FAK was deleted from mouse squamous cell carcinoma (SCC) cells (FAK -/-), and reconstituted with exogenous FAK wild type (wt). Surprisingly, the absence of FAK was associated with increased radio-resistance in advanced SCC cells. FAK re-expression inhibited p53-mediated transcriptional up-regulation of p21, and a sub-set of other p53 target genes involved in DNA repair, after treatment with ionizing radiation. Moreover, p21 depletion promoted radio-sensitisation, implying that FAK-mediated inhibition of p21 induction is responsible for the relative radio-sensitivity of FAK-proficient SCC cells. Our work adds to a growing body of evidence that there is a close functional relationship between integrin/FAK signalling and the p53/p21 pathway, but demonstrates that FAK's role in survival after stress is context-dependent, at least in cancer cells. We suggest that there should be caution when considering inhibiting FAK in combination with radiation, as this may not always be clinically advantageous
Inequalities for C-S seminorms and Lieb functions
No full textAbstractLet Mn be the space of n × n complex matrices. A seminorm ‖ · ‖ on Mn is said to be a C-S seminorm if ‖A*A‖ = ‖AA*‖ for all A ∈ Mn and ‖A‖≤‖B‖ whenever A, B, and B-A are positive semidefinite. If ‖ · ‖ is any nontrivial C-S seminorm on Mn, we show that ‖∣A‖∣ is a unitarily invariant norm on Mn, which permits many known inequalities for unitarily invariant norms to be generalized to the setting of C-S seminorms. We prove a new inequality for C-S seminorms that includes as special cases inequalities of Bhatia et al., for unitarily invariant norms. Finally, we observe that every C-S seminorm belongs to the larger class of Lieb functions, and we prove some new inequalities for this larger class
English castle garrisons in the Anglo-Scottish wars of the fourteenth century
No full textEThOS - Electronic Theses Online ServiceGBUnited Kingdo
The Coconut Tree and the Computer Tiger: Information Technology in Traditional Pacific Societies
No full textThis literature review explores the extent to which Information Technology (IT) has affected the cultures of small traditional Pacific societies, with the South Pacific region as the point of focus. The assumption is that the educational systems of Pacific nations are in the developmental stage with the associated sophisticated technological applications. The thesis asks what if any, cultural challenges of adopting information technology have arisen? The review finds that traditional culture and information technology are in competition in the power stakes of human consideration, reflected in South Pacific indigenous academics seeking independence as researchers and acceptance in their own right. The realisation that culture and technology need to function together requires attaining academic freedom in the aftermath of post-colonial restrictions placed on the indigenous sociological and anthropological imagination. The first part examines the history of information technology generally, and the significance of work already done, providing a perspective of how the subject has developed and become established, assisting in the development and acquisition of the appropriate vocabulary. The review explains and describes the occurrence of information technology in the South Pacific, the effect of globalisation and shared knowledge through ethno-methodology, every day culture in action, describing the ways in which people make the sense they do and through the ways they communicate. In the second part the focus is on the detail of the commonsense character of everyday life and the practices by which they make their actions understandable by others. Scrutiny of how people do what they do provides an explanation of what those people do and why they do it in the way they do. Western form of governance is a reality, with nation building based on Western models of development. National independence and sovereignty with a wave of neo-colonialism and aid dependency led to economic globalisation, with resentment against value systems that erode indigenous values, producing a wave of re-indigenisation facilitated by the revolution known as information technology . There is a coherent body of Pacific thought, with a shared philosophy and ethic on the public agenda. In the material covered, elements standing out are the awareness among growing numbers of Pacific academics of the need for a genuine and far-reaching contextualisation, acknowledging the relevance and applicability of indigenous cultural values in contemporary settings. Second is the success of communities whose initiatives have followed familiar traditional ways they know and understand, reaping rewards. The region has development and governance failures in Papua New Guinea, Solomon Islands and Fiji to name a few; the national state of affairs in some countries is not encouraging. Where good development and governance are occurring, it is usually through the direct initiative of local communities using their knowledge base. The information upheaval is creating new opportunities in the lives of people from small traditional societies. Information Technology expands throughout the social structure of the Pacific in direct proportion to personal computer access literally at one's finger tips
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