On the connectivity of graph Lipscomb's space

A central role in topological dimension theory is played by Lipscomb's space $J_{A}$ since it is a universal space for metric spaces of weight $|A|\geq \aleph _{0}$. On the one hand, Lipscomb's space is the attractor of a possibly infinite iterated function system, i.e. it is a generalized Hutchinson-Barnsley fractal. As, on the other hand, some classical fractal sets are universal spaces, one can conclude that there exists a strong connection between topological dimension theory and fractal set theory. A generalization of Lipscomb's space, using graphs, has been recently introduced (see R. Miculescu, A. Mihail, Graph Lipscomb's space is a generalized Hutchinson-Barnsley fractal, Aequat. Math., \textbf{96} (2022), 1141-1157). It is denoted by J_{A}^{\G} and it is called graph Lipscomb's space associated with the graph \G on the set $A$. It turns out that it is a topological copy of a generalized Hutchinson-Barnsley fractal. This paper provides a characterization of those graphs \G for which J_{A}^{\G} is connected. In the particular case when $A$ is finite, some supplementary characterizations are presented.Comment: 13 page

Cellulose acetate membranes functionalized with resveratrol by covalent immobilization for improved osseointegration

Covalent immobilization of resveratrol onto cellulose acetate polymeric membranes used as coating on a Mg-1Ca-0.2Mn-0.6Zr alloy is presented for potential application in the improvement of osseointegration processes. For this purpose, cellulose acetate membrane is hydrolysed in the presence of potassium hydroxide, followed by covalent immobilization of aminopropyl triethoxy silane. Resveratrol was immobilized onto membranes using glutaraldehyde as linker. The newly synthesised functional membranes were thoroughly characterized for their structural characteristics determination employing X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (FT-IR), Raman spectroscopy, thermogravimetric analysis (TGA/DTG) and scanning electron microscopy (SEM) techniques. Subsequently, in vitro cellular tests were performed for evaluating the cytotoxicity biocompatibility of synthesized materials and also the osseointegration potential of obtained derivatised membrane material. It was demonstrated that both polymeric membranes support viability and proliferation of the pre-osteoblastic MC3T3-E1 cells, thus providing a good protection against the potential harmful effects of the compounds released from coated alloys. Furthermore, cellulose acetate membrane functionalized with resveratrol exhibits a significant increase in alkaline phosphatase activity and extracellular matrix mineralization, suggesting its suitability to function as an implant surface coating for guided bone regeneration

TITANIUM FUNCTIONALIZING AND DERIVATIZING FOR IMPLANTABLE MATERIALS OSSEOINTEGRATION PROPERTIES ENHANCING

The article focuses on titanium functionalizing and derivatizing reactions for implantable materials osseointegration properties enhancing. Thus, the titanium dioxide was activated to the titanium hydroxide (functionalization), being further immobilized on the titanium surface by ethanolamine covalent reactions and (3-aminopropyl)triethoxysilane (APTS) for the osseointegration membranes reactive coating. The derivatizing was based on ether forming reactions between hydroxyl group from the titanium hydroxide surface and the ethanolamine hydroxyl groups and hydrolyzed APTS respectively. The obtained materials were characterized by scanning electron microscopy, FT-IR infrared spectroscopy, contact angle and X-Ray fluorescence

Rib biomechanical properties exhibit diagnostic potential for accurate ageing in forensic investigations

Age estimation remains one of the most challenging tasks in forensic practice when establishing a biological profile of unknown skeletonised remains. Morphological methods based on developmental markers of bones can provide accurate age estimates at a young age, but become highly unreliable for ages over 35 when all developmental markers disappear. This study explores the changes in the biomechanical properties of bone tissue and matrix, which continue to change with age even after skeletal maturity, and their potential value for age estimation. As a proof of concept we investigated the relationship of 28 variables at the macroscopic and microscopic level in rib autopsy samples from 24 individuals. Stepwise regression analysis produced a number of equations one of which with seven variables showed an R2=0.949; a mean residual error of 2.13 yrs ±0.4 (SD) and a maximum residual error value of 2.88 yrs. For forensic purposes, by using only bench top machines in tests which can be carried out within 36 hrs, a set of just 3 variables produced an equation with an R2=0.902 a mean residual error of 3.38 yrs ±2.6 (SD) and a maximum observed residual error 9.26yrs. This method outstrips all existing age-at-death methods based on ribs, thus providing a novel lab based accurate tool in the forensic investigation of human remains. The present application is optimised for fresh (uncompromised by taphonomic conditions) remains, but the potential of the principle and method is vast once the trends of the biomechanical variables are established for other environmental conditions and circumstances

COMPARATIVE STUDIES REGARDING HEAVY ELEMENTS CONCENTRATION IN HUMAN CORTICAL BONE

The heavy metal metabolism in the human hard tissues biostructures can be assessed by individual studies made on targeted groups from the same living area. During lifetime the exposure to the heavy metals due to environment and professional sources leads to their concentration increment at calcified tissues level, their study reflecting thaw the integrated or cumulative exposure. This study is conducted on 16 samples from human hard tissue in order to assess the metallic elemental concentration in bone and to find the influence of the human subject age on the results. Due to the fact that previous studies showed high differences in bones metals concentrations relative to the sex, living area and bone type we used in this study only male human bones, from the same area (Bucharest) and the same bone type (cortical). We supposed that this selection would allow us to assess the average value of the bone metal concentration function of age factor and similar with the natural concentration. Scanning electron microscopy coupled with energy dispersion spectrometry method was chosen to assess the morphology of the studied bones and Ca/P ratio. X-ray fluorescence spectrometric method is proposed for the heavy elements analysis and its accuracy is proved using atomic absorption spectrometry, a well known precise method

Problems in Assessing Thermal Diffusivity of Steel Constituents for Quench Simulation

Presentazione orale TMS 200

Equivalence of viscosity and weak solutions for a p-parabolic equation

We study the relationship of viscosity and weak solutions to the equation partial derivative(t)u - Delta(p)u = f (Du), where p > 1 and f is an element of C(R-N) satisfies suitable assumptions. Our main result is that bounded viscosity supersolutions coincide with bounded lower semicontinuous weak supersolutions. Moreover, we prove the lower semicontinuity of weak supersolutions when p >= 2.peerReviewe