Fretting wear of Ti(CxNy) PVD coatings under variable environmental conditions

Fretting wear as a specific type of degradation is defined as an oscillatory motion at small amplitude between two nominally stationary solid bodies in mutual contact. Under external stresses the interface is being damaged by debris generation and its successive ejections outside the contact area. A potential protection against fretting damage by means of hard coatings is being offered by different surface engineering techniques. For this study TiC, TiN and TiCN hard coatings manufactured by a PVD method have been selected and tested against smooth polycrystalline alumina ball. A fretting test programme has been carried out at the frequency of 5Hz, 100N normal load, 100µm displacement amplitude and at three values of a relative humidity: 10, 50 and 90% at 295-298K temperature. It turned out that the intensity of wear process was depending not only on loading conditions but on environmental ones as well. A significant impact of RH on wear rate and friction behaviour of the coatings under investigation has been observed. Two different damage mechanisms have been identified and related to the phenomena of debris oxidation and debris adhesion to the counterbody surface. In the latter case the debris deposited onto the surface of the alumina ball lead to a change of stress distribution at the interface and as a result to accelerated wear. In this work experiments with variable relative humidity increasing from 10% to 90% within 1 a single fretting test have been completed. It follows from these experiments that there exists an intermediate value of the RH at which the friction coefficient changes rapidly. Finally a dissipated energy approach has been applied in the work in order to quantify and compare fretting wear rates of different hard coatings

MiR-142-3p is downregulated in aggressive p53 mutant mouse models of pancreatic ductal adenocarcinoma by hypermethylation of its locus

Pancreatic ductal adenocarcinoma (PDAC) is an extremely aggressive disease with poor prognostic implications. This is partly due to a large proportion of PDACs carrying mutations in TP53, which impart gain-of-function characteristics that promote metastasis. There is evidence that microRNAs (miRNAs) may play a role in both gain-of-function TP53 mutations and metastasis, but this has not been fully explored in PDAC. Here we set out to identify miRNAs which are specifically dysregulated in metastatic PDAC. To achieve this, we utilised established mouse models of PDAC to profile miRNA expression in primary tumours expressing the metastasis-inducing mutant p53R172H and compared these to two control models carrying mutations, which promote tumour progression but do not induce metastasis. We show that a subset of miRNAs are dysregulated in mouse PDAC tumour tissues expressing mutant p53R172H, primary cell lines derived from mice with the same mutations and in TP53 null cells with ectopic expression of the orthologous human mutation, p53R175H. Specifically, miR-142-3p is downregulated in all of these experimental models. We found that DNA methyltransferase 1 (Dnmt1) is upregulated in tumour tissue and cell lines, which express p53R172H. Inhibition or depletion of Dnmt1 restores miR-142-3p expression. Overexpression of miR-142-3p attenuates the invasive capacity of p53R172H-expressing tumour cells. MiR-142-3p dysregulation is known to be associated with cancer progression, metastasis and the miRNA is downregulated in patients with PDAC. Here we link TP53 gain-of-function mutations to Dnmt1 expression and in turn miR-142-3p expression. Additionally, we show a correlation between expression of these genes and patient survival, suggesting that they may have potential to be therapeutic targets

Transition state theory and the dynamics of hard disks

The dynamics of two and five disk systems confined in a square has been studied using molecular dynamics simulations and compared with the predictions of transition state theory. We determine the partition functions Z and Z^\ddagger of transition state theory using a procedure first used by Salsburg and Wood for the pressure. Our simulations show this procedure and transition state theory are in excellent agreement with the simulations. A generalization of the transition state theory to the case of a large number of disks N is made and shown to be in full agreement with simulations of disks moving in a narrow channel. The same procedure for hard spheres in three dimensions leads to the Vogel-Fulcher-Tammann formula for their alpha relaxation time.Comment: 1 new author, new simulations and figures, less speculation. Now 6 pages, 6 figures, 1 animation. Animation may be viewed at http://www.theory.physics.manchester.ac.uk/~godfrey/supplement/activated_dynamics2.htm

Strong Decays of Strange Charmed P-Wave Mesons

Goldstone boson decays of P-wave $D_s^{**}$ mesons are studied within the framework of Heavy Hadron Chiral Perturbation Theory. We first analyze the simplest single kaon decays of these strange charmed mesons. We derive a model independent prediction for the width of $D_{s2}$ and use experimental information on $D_{s1}$ to constrain the S-wave contribution to $D_1^0$ decay. Single and double pion decay modes are then discussed and shown to be significantly restricted by isospin conservation. We conclude that the pion channels may offer the best hope for detecting one strange member of an otherwise invisible P-wave flavor multiplet.Comment: 16 pages, 2 updated figures not included but available upon request, CALT-68-1902. (Revised estimates for error on $D_{s2}$ width and for isospin violating neutral pion decay of $D'_{s1}$.

Conference scene : Golden Helix Pharmacogenomics Days : educational activities on pharmacogenomics and personalized medicine

The Golden Helix Pharmacogenomics Days are high-profile international educational scientific meetings discussing pharmacogenomics and personalized medicine. Here, we provide an overview of the scientific lectures and the topics discussed during the 4th Golden Helix Pharmacogenomics Day, held in Cagliari, Italy, on 7 October 2011, and the 5th Golden Helix Pharmacogenomics Day, that was held in Msida, Malta, on 3 December 2011. The scientific programs of both events included scientific and company lectures on pharmacogenomics, bioinformatics and personalized medicine by local and international speakers from Europe and the USA.peer-reviewe

Carrier localization mechanisms in InGaN/GaN quantum wells

Localization lengths of the electrons and holes in InGaN/GaN quantum wells have been calculated using numerical solutions of the effective mass Schr\"odinger equation. We have treated the distribution of indium atoms as random and found that the resultant fluctuations in alloy concentration can localize the carriers. By using a locally varying indium concentration function we have calculated the contribution to the potential energy of the carriers from band gap fluctuations, the deformation potential and the spontaneous and piezoelectric fields. We have considered the effect of well width fluctuations and found that these contribute to electron localization, but not to hole localization. We also simulate low temperature photoluminescence spectra and find good agreement with experiment.Comment: 7 pages, 7 figure

A proper understanding of Millikan

Ruth Millikan’s teleological theory of mental content is complex and often misunderstood. This paper motivates and clarifies some of the complexities of the theory, and shows that paying careful attention to its details yields answers to a number of common objections to teleological theories, in particular, the problem of novel mental states, the problem of functionally false beliefs, and problems about indeterminacy or multiplicity of function

Glycosylated haemoglobin (HbA1c) and cortisol levels on admission to intensive care as predictors of outcome

Objective: To evaluate the predictive value of glycosylated haemoglobin and cortisol on admission, in critical care patients. Design: Prospective, observational, single centre study. Setting: 14 bedded Intensive care unit of a tertiary-level university hospital. Patients: 124 consecutive emergency medical and surgical patients. Methods: Data collected on admission included patient demographics, medical history, medication, diagnosis, type of nutrition, TISS28 score, serum blood glucose, Glycosylated haemoglobin (HbA1c), cortisol, mean arterial blood pressure, and the use of inotropes in the first 24hrs. Daily baseline tests included complete blood count, urea and electrolytes, creatinine, twice weekly liver function tests. The primary outcome measure was intensive care unit mortality. Secondary outcome measures were ITU stay, days of ventilation, peak urea, peak creatinine, lowest platelet count, peak bilirubin, lowest Pa/FiO2, and the number of transfusions. Measurements and results: 124 patients (mean age 56.2 years SD 23.2) were included. Regression analysis was used to identify any potential predictors of outcome: HbA1c levels on admission were not found to be significantly associated with mortality (p=0.51), or any other secondary endpoints listed above. However, subgroup analysis revealed a predictive role of HbA1c with regards to length of ITU stay (p= 0.01) and number of days of ventilation (p=0.007) in those patients with a history of diabetes. Glucose level on admission emerged as an independent marker of mortality (p=0.009). Conclusions: This study suggests that HbA1c may not be a predictor of outcome in the general ITU population but may be of predictive value in diabetic ITU patients. On the other hand, blood glucose levels on admission emerged as a predictor of mortality, whilst no association was found between HbA1c and cortisol levels on admission.peer-reviewe