Duality for a boundary driven asymmetric model of energy transport

We study the asymmetric brownian energy, a model of heat conduction defined on the one-dimensional finite lattice with open boundaries. The system is shown to be dual to the symmetric inclusion process with absorbing boundaries. The proof relies on a non-local map transformation procedure relating the model to its symmetric version. As an application, we show how the duality relation can be used to analytically compute suitable exponential moments with respect to the stationary measure

Fibroblast behavior after titanium surfaces exposure.

Background: The main requirements for a good material are its ability to promote attraction and adhesion of bone precursor cells and their proliferation and differentiation. Different biocompatible materials are currently employed as scaffold. Among these, titanium is considered a gold standard because of its biocompatibility and good corrosion resistance. Materials and Methods: The aim of this work was to compare two different AoN titanium layers (GR4 and GR5) to investigate which one had a greater osteoconductive power using human fibroblasts (HFb) culture at two different time-points. The expression levels of some adhesion and traction-resistance related genes (COL11A1, COL2A1, COL9A1, DSP, ELN, HAS1, and TFRC) were analyzed using real time reverse transcription-polymerase chain reaction. Results: After 7 days of treatment with TiA 4GR, the only two up-regulated genes were COL2A1 and DSP. After 15 days of treatment, none of genes over expressed. Conclusion: Our preliminary results suggest that neither AoN 4GR nor AoN 5GR are able to promote the production of protein involved in cell\u2013cell and cell\u2013matrix adhesion and in stress-resistance, required for a good outcome in dental implantolog

Titanium alloys (AoN) and their involvement in osseointegration.

Background: Osseointegration is essential for a long-term successful and inflammation-free dental implant. Such a result depends on osteoblastic cells growth and differentiation at the tissue-implant interface. The aim of this study was to compare two different AoN titanium layers (GR4 and GR5) to investigate which one had a greater osteoconductive power using human osteoblasts (HOb) culture at two different time-points. Materials and Methods: The expression levels of some bone-related (ALPL, COL1A1, COL3A1, SPP1, RUNX2, and SPARC) were analyzed using real time reverse transcription-polymerase chain reaction (real time RT-PCR). Results: Real-time RT-PCR data showed that after 3 days of treatment with TiA4GR, the genes up-regulated were COL3A1, ALPL, SPP1, and RUNX2. Moreover, no difference in gene expression was noticed 4 days later. On the other hand, the genes that overexpressed after 3 days of treatment with AoN5GR were ALPL, SPP1, and RUNX2. In both cases, the expression of COL1A1 and SPARC was negatively regulated. Conclusion: Our data showed that both titanium surfaces led to osteoblasts recruitment, maturation, and differentiation, thus promoting osseointegration at the tissue-implant interface

Titanium nanotubes stimulate osteoblast differentiation of stem cells from pulp and adipose tissue

BACKGROUND: Titanium is the gold standard among materials used for prosthetic devices because of its good mechanical and chemical properties. When exposed to oxygen, titanium becomes an oxide, anatase that is biocompatible and able to induce osseointegration. MATERIALS AND METHODS: IN THIS STUDY WE COMPARED THE EXPRESSION PROFILING OF STEM CELLS CULTIVATED ON TWO TYPES OF SURFACE: Pure titanium disk and nanotube titanium disk in order to detect if nanotube titanium instead (NTD) surface stimulates stem cells towards osteoblast differentiation. RESULTS: Stem cells cultivated on nanotube titanium disks showed the upregulation of bone-related genes RUNX2, FOSL1 and SPP1. CONCLUSIONS: Results demonstrated that nanotube titanium disk surface is more osteo-induced surface compared to titanium disk, promoting the differentiation of mesenchymal stem cells in osteoblasts

Nonconventional averages along arithmetic progressions and lattice spin systems

We study the so-called nonconventional averages in the context of lattice spin systems, or equivalently random colourings of the integers. For i.i.d. colourings, we prove a large deviation principle for the number of monochromatic arithmetic progressions of size two in the box $[1,N]\cap \N$, as $N\to\infty$, with an explicit rate function related to the one-dimensional Ising model. For more general colourings, we prove some bounds for the number of monochromatic arithmetic progressions of arbitrary size, as well as for the maximal progression inside the box $[1,N]\cap \N$. Finally, we relate nonconventional sums along arithmetic progressions of size greater than two to statistical mechanics models in dimension larger than one.Comment: 18 pages, 3 figures. A new section was added on arithmetic progressions of length larger than 2 and statistical mechanics models on Z^d, d>1. To appear in Indagationes Mathematicae (2012