153,185 research outputs found
The relationship of the ADP-ribosylating enzyme from S. solfataricus with DING proteins and its intracellular localization
No full textThe PARPSso thermoprotein from Sulfolobus solfataricus has been identified as a PARP-like enzyme that cleaves -NAD+ to synthesize oligomers of ADP-ribose and cross-reacts with polyclonal anti-PARP-1 catalytic site antibodies. Despite the biochemical properties that allow to correlate it to PARP enzymes, the N-terminal and partial amino acid sequence suggest the sulfolobal enzyme belongs to a different class of enzymes, the DING proteins. Considering the high sequence identity with the human DING protein HPBP and the lack of a nucleotide coding sequence in both human and sulfolobal genomes, we hypothesized that PARPSso might share other features with the human DING. Further analysis of PARPSso amino acid sequence addressed the research towards studying other possible similarities between human and sulfolobal protein and then to explain how PARPSso correlates with canonic PARPs. For the latter question, the peculiar behaviour of the thermozyme, that is biochemically, but not structurally related to the classic PARPs, stimulated to investigate by computational analysis and databank, whether the protein might be phylogenetically related to any already known PARP amino acid sequence.
Moreover, immunochemical and enzymatic crossed analyses were performed to establish whether purified HPBP and PARPSso have common immunoreactive and functional behaviour.
The second part of the research was focused on the localization of PARPSso within the sulfolobal cell. Our interest to this item arose from the property of some DING proteins to be membrane bound, suggested to work as membrane transporters. On the other hand, from previous studies, it is known that PARPSso is only partially solubilized from the starting cell homogenate provided by ICMIB (CNR), and the soluble enzyme is strictly associated with DNA. In this thesis work, whole cells collected by centrifugation from culture medium were subjected to a different extraction procedure. This procedure included also experimental conditions used to differentiate between soluble (i.e. cytoplasmic) and insoluble (i.e. membrane-bound) protein fractions. PARPSso and DNA distributions were determined by enzyme assay, immunoblotting and agarose gel electrophoresis. Reciprocal interactions of thermozyme, nucleic acid and membrane lipids were investigated with different techniques and methodologies (nucleoid preparation, fluorescence binding assays, fluorescence microscopy analysis)
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Ding-graded modules and strongly Ding-graded modules(Ding分次模和强Ding分次模)
No full text研究了分次环R上的Ding分次投射（内射）R-模以及强Ding分次投射（内射）R-模，证明了任意分次环上的Ding分次投射（内射）模类是投射（内射）可解的.研究了强Ding分次投射（内射）R-模与Ding分次投射（内射）R-模之间的关系，以及强Ding分次投射（内射）R-模与非分次的强Ding投射（内射）R-模之间的关系.证明了对有限群分次环R，若M是强Ding投射（内射）R-模，则F(M)是强Ding分次投射（内射）的；若N是强Ding分次投射（内射)R-模，则U(N）是强Ding投射（内射）的
Fighting against Viral Hepatitis: Lessons from Taiwan
No full textViral hepatitis and its sequelae are important health problems worldwide, including Taiwan. For the last 40 years, Taiwan's scientists and health care providers have worked hard to control these sequelae, and the results have been excellent. The author, Ding-Shinn Chen, had a key role in planning and establishing the control program in Taiwan, and participated in the endeavors from the very beginning. In this perspective, he describes how he became interested in research as a medical student, his encounters with hepatitis B and C, how he and his colleagues started early detection of hepatocellular carcinoma (HCC), how he helped Taiwan's government create and implement the Viral Hepatitis Control Program, and how the effectiveness of the program in the decrease of hepatitis B carriage and HCC was monitored. He also discusses how he pioneered the use of interferon- plus ribavirin to treat chronic hepatitis C. Hepatitis B viral load as a risk factor for HCC and cirrhosis in hepatitis B surface antigen carriers is reviewed briefly, as is the prevention of sequelae by antiviral therapies. Finally, Dr. Chen discusses unresolved issues that must be addressed and predicts the changes of the patterns of liver disease in Taiwan beyond the mid-21st century, which is in part affected by the fight against viral hepatitis that was initiated in the early 1980s . CONCLUSION: Dr. Chen's perspective illustrates Taiwan's fight against viral hepatitis over the last 40 years. This experience can be shared by other countries in which the disease is equally prevalent
Ding projective and Ding injective modules over trivial ring extensions
No full textsummary:Let be a trivial extension of a ring by an --bimodule such that , , and have finite flat dimensions. We prove that is a Ding projective left -module if and only if the sequence is exact and is a Ding projective left -module. Analogously, we explicitly describe Ding injective -modules. As applications, we characterize Ding projective and Ding injective modules over Morita context rings with zero bimodule homomorphisms
Nanostructured optical fibre tapers and related applications
No full textIn the last decade, optical fibre tapers have attracted considerable interest because they offer a variety of enabling properties, including large evanescent fields, flexibility, configurability, high confinement, robustness and compactness. These distinctive features have been exploited in a wealth of applications ranging from telecommunication devices to sensors, from optical manipulation to high-Q resonators. Nanostructures on the optical fibre tapers are very promising since the size of the device can be extremely small. With the development of nanostructuring methods, sub-wavelength feature sizes have been achieved. In this thesis, nanostructured optical fibre tapers and some related applications are discussed.Light confinement is limited by diffraction and the minimum spot size is related to the light wavelength. In this thesis, light confinement in two and three dimensions is proposed and achieved with two typologies of nanostructured optical fibre tapers. The first group of devices exploits plasmons excited at the optical fibre tips to obtain high transmissivity, and confine light to a sub-wavelength dimension. Optical fibre tips were designed according to numerical simulations and coated by a layer of gold; an extremely small aperture was then opened at the tip apex. The experimental characterization and simulation results showed their improved transmission efficiency (higher than 10-2) and thermal expansion measurements showed no shape changes could be detected within the accuracy of the system (~2 nm) for 9 mW injected powers. Effective confinements to 10 nm or smaller can be envisaged by decreasing the aperture size and slope angle. Application of this small spot size source can include scanning near-field optical microscope, optical recording, photolithography and bio-sensing.The second group achieves three dimensional light confinement exploiting a Fabry-Perot microcavity formed by a microfibre grating similar to those used in distributed feedback lasers. Microfibres were patterned using a Focused Ion Beam (FIB) system. In this structure, the microcavity provides longitudinal light confinement, whereas air dielectric guiding by the microfibre provides diffraction limited confinement in the other two dimensions. Due to the high refractive index contrast between silica and air, strong reflection can be obtained by only dozens of notches. This device can be used for a wide range of applications, e.g. sensing and triggered single-photon sources.Light confinement in nanostructured optical fibre tapers was exploited in a micrometric thermometer. A compact thermometer based on a broadband microfibre coupler tip showed a dynamic range spanning from room temperature to 1511ºC with a response time of tens of microseconds. This is the highest temperature measured with a silica optical fibre device. An average sensitivity of 11.96 pm/ºC was achieved for a coupler tip with ~2.5 µm diameter. A resolution of 0.66ºC was achieved for a coupler tip diameter of ~12.6 µm. Better resolution can be achieved with smaller size microfibre coupler tips.Optical fibre tapers are commonly used to couple light to selected resonator modes. Here FIB was used to inscribe microgrooves on optical Bottleneck Microresonator (BMR) surfaces to excite selected whispering gallery modes. By monitoring the transmission spectrum of the optical fibre taper, substantial spectral clean-up was obtained in appropriately scarred BMRs. Single high-Q mode operation can be achieved by either using two asymmetrical perpendicular scars or placing the grooves closer to the BMR centre, providing the potential for high performance sensors and other optical devices.Finally, strong three dimensional localization has been achieved in Plasmonic Slot Nano-Resonators (PSNRs) embedded in a gold-coated optical fibre tapers. Different shapes PSNRs, embedded in thin gold metal film coated plasmonic microfibre, were numerically investigated. The intensity enhancement (in excess of 106) and the resonance wavelength depend on both the PSNR and microfibre dimensions. Theoretically and experimentally, the transversal excitation of a rectangular PSNR embedded in a thin gold film coated plasmonic fibre tip was discussed for the first time, and showed high localization and strong enhancement (7.24×103). This device can find a wide range of applications such as surface-enhanced Raman scattering, optical filtering, spectroscopy and bio-sensing
DING proteins are from Pseudomonas
No full textDING proteins have been described as animal and plant proteins with potential biomineralisation, receptor or signalling roles that have been characterised by an N-terminal DINGGG-sequence. However, these sequences have only ever been identified as either N-terminal peptides or partial cDNA sequences, and have yet to be detected in any of the many genomic animal and plant genomes now available. Microbial relatives of the DING proteins have been described, which appear to be periplasmic phosphate-binding proteins. Recently, full-length Pseudomonas aeruginosa UCBPP-PA14 and Hypericum perforatum genes have been sequenced that show high homology to the published DING protein N-terminal sequences, and small peptides previously identified in conjunction with the peptide sequencing of DING proteins can also be mapped to regions across these full-length sequences. Searching with these sequences identifies other plant and animal cDNA fragments in the public nucleotide databases, and, additionally, an unordered rat genomic contig that contains a DING-like sequence on a small fragment. Analysing the codon usage of these DNA sequences identifies all of these sequences as of Pseudomonas origin, suggesting that DING proteins do not exist in eukaryotes, but instead are potentially due to microbial contamination or infection.</p
A Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Ring up the curtain on DING proteins
No full textAbstractDING proteins have a characteristic DINGGG- or closely related N-terminal sequence. One is found in human synovial fluid, and may be associated with rheumatoid arthritis. Other examples have receptor or signalling roles in various human and animal cells, or are involved in biomineralisation, and several of them bind to phytochemicals. As plant DING proteins have recently been discovered, we hypothesise that the DING protein-phytochemical association may represent one aspect of a ubiquitous receptor-linked signalling system. Several microbial proteins related to DING proteins have phosphatase activity, which may relate to biomineralisation in eukaryotic systems. Plant DING proteins and their microbial relatives may elicit allergic responses leading to arthritic disease
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