Asymptotic Limits and Zeros of Chromatic Polynomials and Ground State Entropy of Potts Antiferromagnets

We study the asymptotic limiting function $W({G},q) = \lim_{n \to \infty}P(G,q)^{1/n}$, where $P(G,q)$ is the chromatic polynomial for a graph $G$ with $n$ vertices. We first discuss a subtlety in the definition of $W({G},q)$ resulting from the fact that at certain special points $q_s$, the following limits do not commute: $\lim_{n \to \infty} \lim_{q \to q_s} P(G,q)^{1/n} \ne \lim_{q \to q_s} \lim_{n \to \infty} P(G,q)^{1/n}$. We then present exact calculations of $W({G},q)$ and determine the corresponding analytic structure in the complex $q$ plane for a number of families of graphs ${G}$, including circuits, wheels, biwheels, bipyramids, and (cyclic and twisted) ladders. We study the zeros of the corresponding chromatic polynomials and prove a theorem that for certain families of graphs, all but a finite number of the zeros lie exactly on a unit circle, whose position depends on the family. Using the connection of $P(G,q)$ with the zero-temperature Potts antiferromagnet, we derive a theorem concerning the maximal finite real point of non-analyticity in $W({G},q)$, denoted $q_c$ and apply this theorem to deduce that $q_c(sq)=3$ and $q_c(hc) = (3+\sqrt{5})/2$ for the square and honeycomb lattices. Finally, numerical calculations of $W(hc,q)$ and $W(sq,q)$ are presented and compared with series expansions and bounds.Comment: 33 pages, Latex, 5 postscript figures, published version; includes further comments on large-q serie

Wettability Modification of Nanomaterials by Low-Energy Electron Flux

Controllable modification of surface free energy and related properties (wettability, hygroscopicity, agglomeration, etc.) of powders allows both understanding of fine physical mechanism acting on nanoparticle surfaces and improvement of their key characteristics in a number of nanotechnology applications. In this work, we report on the method we developed for electron-induced surface energy and modification of basic, related properties of powders of quite different physical origins such as diamond and ZnO. The applied technique has afforded gradual tuning of the surface free energy, resulting in a wide range of wettability modulation. In ZnO nanomaterial, the wettability has been strongly modified, while for the diamond particles identical electron treatment leads to a weak variation of the same property. Detailed investigation into electron-modified wettability properties has been performed by the use of capillary rise method using a few probing liquids. Basic thermodynamic approaches have been applied to calculations of components of solid–liquid interaction energy. We show that defect-free, low-energy electron treatment technique strongly varies elementary interface interactions and may be used for the development of new technology in the field of nanomaterials

The substantiation of the pre-polymerization heating efficiency of the dental nanocomposite material

Objective: To evaluate the effect of pre-polymerization heating of nanocomposite filling materials on their strength properties within one manufacture group. Material and Methods: Two nanocomposite filling materials Enamel Plus HRi Universal Dentin® and Universal Enamel® were used. The linear thermal expansion coefficient (LTEC), Young's modulus and penetration depth were determined during the tests. Changes in the structure of materials were evaluated using electron scanning microscopy. Results: Dentin nanocomposite samples after pre-heating and polymerization have higher LTEC after 30°C compared to dentine nanocomposite untreated samples with statistically significance started at 62°C (p<0.05) and higher temperature. Pre-polymerization heated samples had a statistically higher LTEC (p<0.05) at 57°С. It was revealed that Young's modulus of the dentin nanocomposite samples after thermal processing at 55°C was higher in total after the first heating cycle by 15% compared to the untreated dentin nanocomposite samples (p<0.05). The volume of total porosity after pre-heating decreased to 5-7% (p<0.05). Conclusion: The material that has undergone preliminary heat processing is significantly less deformed under load than the material that does not have thermal processing during the research was established and also has a denser structure. © 2020, Association of Support to Oral Health Research (APESB). All rights reserved

The Comparison Analysis of Orthophosphoric and Maleic Acids in the Smear Layer Removal Techniques

Different solutions have been used to remove the smear layer during endodontic treatment. Their efficacy, biological response and side effects differ from each other. The purpose of this review article is to assess systematically the available scientific evidence about the effectiveness of orthophosphoric and maleic acids in smear layer removing. The study of publications was produced in the electronic databases such as Google Scholar, PubMed during a systematic review of the literature. Included articles contain information about using orthophosphoric and maleic acids in smear layer removing and their difference. The publication date criterion was selected from January 2011 to September 2021. 55 articles were viewed during the review. After analyzing the literature for inclusion criteria, the total number of publications has become 10. According to literature data, orthophosphoric and maleic acids are both effective in removing the smear layer, however, they have some differences © 2022. Journal of International Dental and Medical Research.All Rights Reserved

Dislocations mediate hydrogen retention in tungsten

In this letter, a comprehensive mechanism for the nucleation and growth of bubbles on dislocations under plasma exposure of tungsten is proposed. The mechanism reconciles long-standing experimental observations of hydrogen isotopes retention, essentially defined by material microstructure, and so far not fully explained. Hence, this work provides an important link to unify material's modelling with experimental assessment of W and W-based alloys as candidates for plasma facing components

Analysis of accessory canals as important anatomical structures in the anterior maxilla with cone beam computed tomography

The aim of this study is to analyze the diameter and localization of terminal part CS to prevent its damage during implant placement in the anterior maxilla. 150 CBCT scans of 61 males and 89 females in the age span of 24 to 80 years using 8 x 8 field of view. were analyzed in Ez3D2009 (Vatech) software on panoramic and cross-sectional views with 0.5mm, 1mm, 3 mm and 10 mm slice thickness. The CS visualization was graded with the four-point rating scale and the localization was distributed according to Oliveira-Santos. Evaluating CBCT scans with 0.5 mm slice thickness the alveolar process part of CS was evident in 101 of 150 patients (67% of total patients). 22 of these 101 patients (21.7%) presented with CS on the right side, 32 (31.6%) patients on the left side and 47 (46.7%) patients on both sides. Most frequently CS was localized in the lateral incisor region (33.5%, n=50). Analyzing CBCT scans with 0.5 mm and 1 mm slice thickness on both sides CS was visualized in 49%, with 3 mm slice thickness in 40% and with 10 mm slice thickness in 18%. Mean diameter and length of terminal part CS were 0,95 ± 0,24 and 11,78 ± 3,32 consequently. CS was located palatally in 76% (n=113), centrally in 12% (n=18) and buccally in 12% (n=18). It is important to plan dental implant placement with CBCT and by not neglecting the use of surgical guides. © 2020 University of Dicle

Temporomandibular joint in systemic lupus erythematosus: Literature review

The aim of this study is to analyze the literature on temporomandibular joint (TMJ) diseases in systemic lupus erythematosus (SLE). This literature review includes articles from 2003 to 2018 describing clinical studies or clinical cases of TMJ diseases in SLE. Publications not related to the study topic and those that did not have enough data were excluded from the survey. The investigation initially involved 35 articles, four of which were selected. The articles included studies on the pediatric and adult populations. In all the studies, except for one, a clinical examination was carried out, and in three of the studies additional radiographic methods were used. The information also included an overview of drug therapy. At present, there is limited information on the TMJ disorders in systemic lupus erythematosus and further research is required to properly diagnose the disease in dental appointments. © 2019 Journal of International Dental and Medical Research