60,616 research outputs found
Potential Antimicrobial Methods for Provisionalizing Teeth After Endodontic Treatment
POTENTIAL ANTIMICROBIAL METHODS FOR PROVISIONALIZING TEETH AFTER ENDODONTIC TREATMENT
By Laura T. Garden, DDS
A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Dentistry at Virginia Commonwealth University.
Virginia Commonwealth University, 2018
Thesis Advisor: Garry Myers, DDS
Department of Endodontics
Objective:To evaluate the effectiveness of a Chlorhexidine soaked cotton pellet on bacterial leakage.
Methods: Fifty-one extracted teeth, including six controls, were instrumented, obturated, and sealed with either a cotton pellet (CP), 2% Chlorhexidine soaked cotton pellet (CHX), or a Permaflo orifice barrier (OB). Each root was suspended between two chambers: the coronal chamber inoculated with brain heart infusion broth and colony-forming units of Enterococcus faecalis, the apical chamber with brain heart infusion broth and phenol red. The latter was checked daily for turbidity, indicating bacterial leakage.
Results: All open and closed control groups had leaked by day 7. The average CP tooth survived for 13.1 days whereas the CHX and OB teeth leaked by an average of 5.8 days.
Conclusion:There is insufficient evidence to support the use of a Chlorhexidine soaked cotton pellet. The results were not as expected and the study design should be re-evaluated
Simple derivation of the frequency dependent complex heat capacity
This paper gives a simple derivation of the well-known expression of the
frequency dependent complex heat capacity in modulated temperature experiments.
It aims at clarified again that the generalized calorimetric susceptibility is
only due to the non-equilibrium behaviour occurring in the vicinity of
thermodynamic equilibrium of slow internal degrees of freedom of a sample when
the temperature oscillates at a well determined frequency
Gossip in a Smartphone Peer-to-Peer Network
In this paper, we study the fundamental problem of gossip in the mobile
telephone model: a recently introduced variation of the classical telephone
model modified to better describe the local peer-to-peer communication services
implemented in many popular smartphone operating systems. In more detail, the
mobile telephone model differs from the classical telephone model in three
ways: (1) each device can participate in at most one connection per round; (2)
the network topology can undergo a parameterized rate of change; and (3)
devices can advertise a parameterized number of bits about their state to their
neighbors in each round before connection attempts are initiated. We begin by
describing and analyzing new randomized gossip algorithms in this model under
the harsh assumption of a network topology that can change completely in every
round. We prove a significant time complexity gap between the case where nodes
can advertise bits to their neighbors in each round, and the case where
nodes can advertise bit. For the latter assumption, we present two
solutions: the first depends on a shared randomness source, while the second
eliminates this assumption using a pseudorandomness generator we prove to exist
with a novel generalization of a classical result from the study of two-party
communication complexity. We then turn our attention to the easier case where
the topology graph is stable, and describe and analyze a new gossip algorithm
that provides a substantial performance improvement for many parameters. We
conclude by studying a relaxed version of gossip in which it is only necessary
for nodes to each learn a specified fraction of the messages in the system.Comment: Extended Abstract to Appear in the Proceedings of the ACM Conference
on the Principles of Distributed Computing (PODC 2017
Entropy production in ac-calorimetry
In calorimetry and particularly in heat capacity measurements, different
characteristic relaxation time constants may perturb the experiment which
cannot be considered at thermodynamic equilibrium. In this case, thermodynamics
of irreversible processes has to be taken into account and the calorimetric
measurements must be considered as dynamic. In a temperature modulated
experiment, such as ac-calorimetry, these non-equilibrium experiments give rise
to the notion of frequency dependent complex heat capacity. In this paper, it
is shown that for each irreversible process an experimental frequency dependent
complex heat capacity can be inferred. Furthermore, we demonstrate rigorously
that a same equality connects the imaginary part of these different complex
heat capacities with the entropy produced during these irreversible processes.
Finally, we claim that the presence of an imaginary part in the measured heat
capacity always indicates that a certain amount of heat does not participate to
the classical equilibrium heat capacity of the sample when measured over the
observation time scale
Indigenous affairs: a quick guide to key internet links
Provides links to key resources for Indigenous affairs in Australia, including information on \u27Closing the Gap\u27 agreements, funding, geography, and government agencies.
Summary
This Quick Guide provides links to:
the Council of Australian Government (COAG) key agreements under ‘Closing the Gap’
a listing of Australian Government departments with responsibility for Indigenous affairs and their key programmes
statistics and funding
a map of ‘Aboriginal Australia’
directories of Indigenous organisations and businesses
key organisations outside Government departments
state, territory and local government websites and
overseas websites
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