970 research outputs found

    Barriers to the use of a diagnostic oral microbiology laboratory by general dental practitioners

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    OBJECTIVE: To identify barriers on the use of diagnostic microbiology facilities in general dental practice. DESIGN: A cross-sectional survey using a postal questionnaire. SETTING: Primary/secondary care interface between the diagnostic oral microbiology laboratory, University of Glasgow Dental Hospital and School, Glasgow and dental practitioners within the surrounding health boards, 1998. SUBJECTS: All GDPs (797) within Argyll and Clyde, Ayrshire and Arran, Lanarkshire and Greater Glasgow Health Boards. MAIN OUTCOME MEASURES: The responses were expressed as both absolute and relative frequencies. RESULTS: Responses were received from 430 (55%). The most frequent reason for failure to use the service was lack of information, with more than half of the respondents claiming to be unaware of the facility. Lack of request forms and sampling equipment were also viewed as barriers to using the service. CONCLUSIONS: The laboratory is failing to successfully communicate its role in addressing the growing burden of antibiotic resistance in the community and must be more proactive in encouraging appropriate use and increasing accessibility of the service to GDPs

    Slower Speed and Stronger Coupling: Adaptive Mechanisms of Self-Organized Chaos Synchronization

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    We show that two initially weakly coupled chaotic systems can achieve self-organized synchronization by adaptively reducing their speed and/or enhancing the coupling strength. Explicit adaptive algorithms for speed-reduction and coupling-enhancement are provided. We apply these algorithms to the self-organized synchronization of two coupled Lorenz systems. It is found that after a long-time self-organized process, the two coupled chaotic systems can achieve synchronization with almost minimum required coupling-speed ratio.Comment: 4 pages, 5 figure

    Hexafluoroisopropanol and Acetyl Chloride Promoted Catalytic Hydroarylation with Phenols

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    We report a catalytic hydroarylation method to convert phenols to dihydrocoumarins in hexafluoroisopropanol (HFIP) using acid generated from sub-stoichiometric amounts of acetyl chloride as catalyst. Attractive elements include easy set-up and isolation, and applicability to a range of phenols including natural product substrates

    Characterization of unresolved and unclassified sources detected in radio continuum surveys of the Galactic plane

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    The continuum emission from 1 to 2 GHz of The HI/OH/Recombination line survey of the inner Milky Way (THOR) at 0.5) of the FIRST survey indicates that these sources might be high z extragalactic compact objects. The similar pattern of one-point and two-point statistics of unclassified and compact sources with extragalactic surveys and simulations confirms the extragalactic origin of these sources

    Fourier Acceleration of Langevin Molecular Dynamics

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    Fourier acceleration has been successfully applied to the simulation of lattice field theories for more than a decade. In this paper, we extend the method to the dynamics of discrete particles moving in continuum. Although our method is based on a mapping of the particles' dynamics to a regular grid so that discrete Fourier transforms may be taken, it should be emphasized that the introduction of the grid is a purely algorithmic device and that no smoothing, coarse-graining or mean-field approximations are made. The method thus can be applied to the equations of motion of molecular dynamics (MD), or its Langevin or Brownian variants. For example, in Langevin MD simulations our acceleration technique permits a straightforward spectral decomposition of forces so that the long-wavelength modes are integrated with a longer time step, thereby reducing the time required to reach equilibrium or to decorrelate the system in equilibrium. Speedup factors of up to 30 are observed relative to pure (unaccelerated) Langevin MD. As with acceleration of critical lattice models, even further gains relative to the unaccelerated method are expected for larger systems. Preliminary results for Fourier-accelerated molecular dynamics are presented in order to illustrate the basic concepts. Possible extensions of the method and further lines of research are discussed.Comment: 11 pages, two illustrations included using graphic

    The influence of gene expression time delays on Gierer-Meinhardt pattern formation systems

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    There are numerous examples of morphogen gradients controlling long range signalling in developmental and cellular systems. The prospect of two such interacting morphogens instigating long range self-organisation in biological systems via a Turing bifurcation has been explored, postulated, or implicated in the context of numerous developmental processes. However, modelling investigations of cellular systems typically neglect the influence of gene expression on such dynamics, even though transcription and translation are observed to be important in morphogenetic systems. In particular, the influence of gene expression on a large class of Turing bifurcation models, namely those with pure kinetics such as the Gierer–Meinhardt system, is unexplored. Our investigations demonstrate that the behaviour of the Gierer–Meinhardt model profoundly changes on the inclusion of gene expression dynamics and is sensitive to the sub-cellular details of gene expression. Features such as concentration blow up, morphogen oscillations and radical sensitivities to the duration of gene expression are observed and, at best, severely restrict the possible parameter spaces for feasible biological behaviour. These results also indicate that the behaviour of Turing pattern formation systems on the inclusion of gene expression time delays may provide a means of distinguishing between possible forms of interaction kinetics. Finally, this study also emphasises that sub-cellular and gene expression dynamics should not be simply neglected in models of long range biological pattern formation via morphogens

    Predicting the Amplitude of a Solar Cycle Using the North-South Asymmetry in the Previous Cycle: II. An Improved Prediction for Solar Cycle~24

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    Recently, using Greenwich and Solar Optical Observing Network sunspot group data during the period 1874-2006, (Javaraiah, MNRAS, 377, L34, 2007: Paper I), has found that: (1) the sum of the areas of the sunspot groups in 0-10 deg latitude interval of the Sun's northern hemisphere and in the time-interval of -1.35 year to +2.15 year from the time of the preceding minimum of a solar cycle n correlates well (corr. coeff. r=0.947) with the amplitude (maximum of the smoothed monthly sunspot number) of the next cycle n+1. (2) The sum of the areas of the spot groups in 0-10 deg latitude interval of the southern hemisphere and in the time-interval of 1.0 year to 1.75 year just after the time of the maximum of the cycle n correlates very well (r=0.966) with the amplitude of cycle n+1. Using these relations, (1) and (2), the values 112 + or - 13 and 74 + or -10, respectively, were predicted in Paper I for the amplitude of the upcoming cycle 24. Here we found that in case of (1), the north-south asymmetry in the area sum of a cycle n also has a relationship, say (3), with the amplitude of cycle n+1, which is similar to (1) but more statistically significant (r=0.968) like (2). By using (3) it is possible to predict the amplitude of a cycle with a better accuracy by about 13 years in advance, and we get 103 + or -10 for the amplitude of the upcoming cycle 24. However, we found a similar but a more statistically significant (r=0.983) relationship, say (4), by using the sum of the area sum used in (2) and the north-south difference used in (3). By using (4) it is possible to predict the amplitude of a cycle by about 9 years in advance with a high accuracy and we get 87 + or - 7 for the amplitude of cycle 24.Comment: 21 pages, 7 figures, Published in Solar Physics 252, 419-439 (2008

    Antiulcer and Anti-inflammatory Activity of Aerial Parts Enicostemma littorale Blume

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    The antiulcer and in vitro anti-inflammatory activities of the aerial parts of Enicostemma littorale against aspirin, ethanol, and pyloric ligation-induced ulcers in rats and bovine serum albumin denaturation were studied. The extract (200 mg/kg and 400 mg/kg po) was administered to the overnight fasted rats, one hour prior to aspirin / alcohol / pyloric ligation challenge. The ulcer index, tissue GSH levels, and lipid peroxidation levels were estimated in all the models of ulcers and the volume of gastric secretion, acidity, and pH, were estimated in the pyloric ligation model of ulcers. Pretreatment with the extract showed a dose-dependent decrease in the ulcer index (Against Aspirin, ethanol challenge, and pyloric ligation. The prior administration of the extract also reduced the total acidity, free acidity, and volume of gastric secretion, and elevated the gastric pH. In addition, it was also observed that the extract inhibited the serum albumin denaturation in a dose-dependent manner. It may be concluded that the methanolic extract possesses antiulcer activity, and the anti-inflammatory activity of the extract may be attributed to the antioxidant potential, as reported earlier
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