Enumeration of derangements with descents in prescribed positions

We enumerate derangements with descents in prescribed positions. A generating function was given by Guo-Niu Han and Guoce Xin in 2007. We give a combinatorial proof of this result, and derive several explicit formulas. To this end, we consider fixed point $\lambda$-coloured permutations, which are easily enumerated. Several formulae regarding these numbers are given, as well as a generalisation of Euler's difference tables. We also prove that except in a trivial special case, if a permutation $\pi$ is chosen uniformly among all permutations on $n$ elements, the events that $\pi$ has descents in a set $S$ of positions, and that $\pi$ is a derangement, are positively correlated

Enumeration of derangements with descents in prescribed positions

We enumerate derangements with descents in prescribed positions. A generating function was given by Guo-Niu Han and Guoce Xin in 2007. We give a combinatorial proof of this result, and derive several explicit formulas. To this end, we consider fixed point $\lambda$-coloured permutations, which are easily enumerated. Several formulae regarding these numbers are given, as well as a generalisation of Euler's difference tables. We also prove that except in a trivial special case, if a permutation $\pi$ is chosen uniformly among all permutations on $n$ elements, the events that $\pi$ has descents in a set $S$ of positions, and that $\pi$ is a derangement, are positively correlated

Temporomandibular joint pain and associated magnetic resonance findings: a retrospective study with a control group

Background To better understand and evaluate clinical usefulness of magnetic resonance imaging (MRI) in diagnosis and treatment of temporomandibular disorders (TMD), parameters for the evaluation are useful. Purpose To assess a clinically suitable staging system for evaluation of MRI of the temporomandibular joint (TMJ) and correlate the findings with age and some clinical symptoms of the TMJ. Material and Methods Retrospective analysis of 79 consecutive patients with clinical temporomandibular disorder or diagnosed inflammatory arthritis. Twenty-six healthy volunteers were included as controls. Existing data included TMJ pain, limited mouth opening (<30 mm) and corresponding MRI evaluations of the TMJs. Results The patients with clinical TMD complaints had statistically significantly more anterior disc displacement (ADD), disc deformation, caput flattening, surface destructions, osteophytes, and caput edema diagnosed by MRI compared to the controls. Among the arthritis patients, ADD, effusion, caput flattening, surface destructions, osteophytes, and caput edema were significantly more prevalent compared to the healthy volunteers. In the control group, disc deformation and presence of osteophytes significantly increased with age, and a borderline significance was found for ADD and surface destructions on the condylar head. No statistically significant associations were found between investigated clinical and MRI parameters. Conclusion This study presents a clinically suitable staging system for comparable MRI findings in the TMJs. Our results indicate that some findings are due to age-related degenerative changes rather than pathological changes. Results also show that clinical findings such as pain and limited mouth opening may not be related to changes diagnosed by MRI.publishedVersio

Dynamic in situ chromosome immobilisation and DNA extraction using localized poly(N-isopropylacrylamide) phase transition

A method of in situ chromosome immobilisation and DNA extraction in a microfluidic polymer chip was presented. Light-induced local heating was used to induce poly(N-isopropylacrylamide) phase transition in order to create a hydrogel and embed a single chromosome such that it was immobilised. This was achieved with the use of a near-infrared laser focused on an absorption layer integrated in the polymer chip in close proximity to the microchannel. It was possible to proceed to DNA extraction while holding on the chromosome at an arbitrary location by introducing protease K into the microchannel

Higher plasma drug levels in elderly people living with HIV treated with darunavir

Background The proportion of elderly people living with HIV-1 (PLHIV) is rising. In older patients, comorbidities and concomitant medications are more frequent, increasing the risk of potential drug-drug interactions (PDDIs). Data on the pharmacokinetics of ART in individuals aged &lt; 65 years of age are scarce. We compared plasma drug levels of ART, PDDIs, and sideeffects in PLHIV aged &lt; 65 years of age, with controls &gt; 49 years of age. Methods Patients &lt; 65 years of age and controls &gt; 49 years of age, all of whom were on stable treatment with atazanavir (ATV), darunavir (DRV), or efavirenz (EFV) were included cross-sectionally. Plasma drug levels of ART were analyzed, comorbidities, concomitant medication, adherence, and side-effects recorded, and PDDIs analyzed using drug interactions databases. Results Between 2013 and 2015, we included 100 individuals ≥ 65 years of age (study group) and 99 controls (&lt;49 years of age). Steady-state DRV concentrations were significantly higher in the study group than in the control group (p = 0.047). In the ATV group there was a trend towards a significant difference (p = 0.056). No significant differences were found in the EFV arm. The DRV arm had a higher frequency of reported side-effects than the ATV and EFV arms in the study group (36.7% vs. 0% and 23.8% respectively (p = 0.014), with significant differences between DRV vs. ATV, and EFV vs. ATV). Conclusions Higher steady-state plasma levels of DRV and ATV (but not EFV) were found in PLHIV aged &lt; 65 years of age, compared to controls &gt;49 years of age