91 research outputs found
On Wireless Scheduling Using the Mean Power Assignment
In this paper the problem of scheduling with power control in wireless
networks is studied: given a set of communication requests, one needs to assign
the powers of the network nodes, and schedule the transmissions so that they
can be done in a minimum time, taking into account the signal interference of
concurrently transmitting nodes. The signal interference is modeled by SINR
constraints. Approximation algorithms are given for this problem, which use the
mean power assignment. The problem of schduling with fixed mean power
assignment is also considered, and approximation guarantees are proven
Requirements and infection prophylaxis for internally cooled implant drills
Implant site preparation is crucially important to long-term success. Heat generation
during drilling is unfavourable, since bone is relatively susceptible to heat,
depending on its vascularisation and microstructure. Numerous factors such as
drilling pressure, number of revolutions, drill design, wear and material, drilling
depth and cooling influence heat generation. Internally cooled drills are, therefore,
increasingly used, even though the improved cooling effect compared to
conventional externally cooled drills is controversial. Internally cooled drills may
have the disadvantage of a germ reservoir developing in the cooling channel.
This study aimed to examine the effects of disinfection and sterilisation of internally
cooled drills. After contamination of the cooling channel with suitable bioindicators
(Enterococcus faecium, ATCC 6057 and spores of Bacillus stearothermophilus,
ATCC 7953), the drills were disinfected (disinfection solution ID 220,
Dürr Dental) and autoclaved (Webeco, E5S90, 134°C, 2.6 bar, 5 min). Disinfection
was not completely effective except after pre-cleaning. By means of sterilisation
all spores of Bacillus stearothermophilus were completely killed. Internally
cooled drills can be successfully disinfected by means of this hygienic procedure
routinely used in dental practice and no source of infection is created
Critical considerations on the diagnostic appraisal, adaptation and remodelling of bone graft substitutes
The diagnostic assessment of skeletal defects has a long-standing tradition. As
a result of the development of new bone grafting materials, the demands on
diagnostic assessment have also increased. The mode and quality of diagnostic
appraisal are crucial to further clinical use and outcome prediction. Alongside
traditional clinical and biological techniques, molecular biological methods have
gained a broad scope of application and will be used even more frequently in
the future
Replication of the association of chromosomal region 9p21.3 with generalized aggressive periodontitis (gAgP) using an independent case-control cohort
Background: The human chromosomal region 9p21.3 has been shown to be strongly associated with Coronary Heart Disease (CHD) in several Genome-wide Association Studies (GWAS). Recently, this region has also been shown to be associated with Aggressive Periodontitis (AgP), strengthening the hypothesis that the established epidemiological association between periodontitis and CHD is caused by a shared genetic background, in addition to common environmental and behavioural risk factors. However, the size of the analyzed cohorts in this primary analysis was small compared to other association studies on complex diseases. Using our own AgP cohort, we attempted to confirm the described associations for the chromosomal region 9p21.3. Methods: We analyzed our cohort consisting of patients suffering from the most severe form of AgP, generalized AgP (gAgP) (n = 130) and appropriate periodontally healthy control individuals (n = 339) by genotyping four tagging SNPs (rs2891168, rs1333042, rs1333048 and rs496892), located in the chromosomal region 9p21.3, that have been associated with AgP. Results: The results confirmed significant associations between three of the four SNPs and gAgP. The combination of our results with those from the study which described this association for the first time in a meta-analysis of the four tagging SNPs produced clearly lower p-values compared with the results of each individual study. According to these results, the most plausible genetic model for the association of all four tested SNPs with gAgP seems to be the multiplicative one. Conclusion: We positively replicated the finding of an association between the chromosomal region 9p21.3 and gAgP. This result strengthens support for the hypothesis that shared susceptibility genes within this chromosomal locus might be involved in the pathogenesis of both CHD and gAgP
Mechanism of Action of Cyclophilin A Explored by Metadynamics Simulations
Trans/cis prolyl isomerisation is involved in several biological processes, including the development of numerous diseases. In the HIV-1 capsid protein (CA), such a process takes place in the uncoating and recruitment of the virion and is catalyzed by cyclophilin A (CypA). Here, we use metadynamics simulations to investigate the isomerization of CA's model substrate HAGPIA in water and in its target protein CypA. Our results allow us to propose a novel mechanistic hypothesis, which is finally consistent with all of the available molecular biology data
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