Utjecaj trajanja ciklusa prešanja na ponašanje u primjeni ploče izrađene od kemijski modificiranih čestica

Although acetylation is effective in achieving high hydrophobicity, dimensional stability, and decay resistance of particleboards, springback and mechanical strength loss in modified boards should be improved to maintain high performance of this method. It is questioned if acetylation, due to the hydrophobic nature of modified flakes, could interfere with the polymerization reaction of the phenolic resin. In this research, the effect of different press durations on bioresistance, physical and mechanical behavior of acetylated particleboards at various weight percent gains (WPG) was investigated. Results showed that acetylated boards possessed very low moisture content, water absorption, thickness swelling and biological degradation values compared to control boards. Increasing press time intensified reduction in these boards, with the exception in untreated boards. Also acetylation resulted in high correlation between the springback and the strength losses of the boards due to weak bonding between the wood flakes. Prolongation of the press time in the acetylated boards caused significant reduction in springback and mechanical loss. Regarding the outdoor use with biological degradation for modified boards, an increase in the press time for improving these properties might be recommended.Iako je acetiliranje učinkovit postupak za postizanje visoke hidrofobnosti, stabilnosti dimenzija i otpornosti ploča iverica na propadanje, nužno je spriječiti njezine negativne posljedice kao što je smanjenje mehaničkih svojstava ploča, kako bi se održala visoka učinkovitost te metode. Postavlja se pitanje može li acetilacija zbog hidrofobne prirode modificiranog iverja utjecati na reakciju polimerizacije fenolne smole. U ovom se radu istražuje utjecaj različitog trajanja postupka prešanja na biološku otpornost iverice te fizikalno i mehaničko ponašanje acetiliranih ploča iverica pri različitim postocima porasta težine (WPG). Rezultati su pokazali da acetilirane ploče imaju vrlo nizak sadržaj vode, slabo upijaju vodu, manje debljinski bubre i bolja im je otpornost na biološku razgradnju u usporedbi s kontrolnim uzorcima ploče. Povećanje vremena prešanja poboljšava sva prenavedena svojstva, osim u nemodificiranih ploča. Također, acetilacija je rezultirala visokom korelacijom između nereverzibilnog bubrenja i gubitka čvrstoće ploče zbog slabih veza među drvnim iverjem. Produljenje vremena prešanja acetiliranih ploča iverica uzrokovalo je znatno smanjenje bubrenja i gubitak mehaničkih svojstava ploča. S obzirom na vanjsku uporabu ploča iverica i potrebnu otpornost na biološku razgradnju modificiranih ploča, preporučuje se povećati vrijeme prešanja kako bi se poboljšalo svojstvo biološke otpornosti ploča iverica

Quartic Graphs with Minimum Spectral Gap

Aldous and Fill conjectured that the maximum relaxation time for the random walk on a connected regular graph with $n$ vertices is $(1+o(1)) \frac{3n^2}{2\pi^2}$. This conjecture can be rephrased in terms of the spectral gap as follows: the spectral gap (algebraic connectivity) of a connected $k$-regular graph on $n$ vertices is at least $(1+o(1))\frac{2k\pi^2}{3n^2}$, and the bound is attained for at least one value of $k$. We determine the structure of connected quartic graphs on $n$ vertices with minimum spectral gap which enable us to show that the minimum spectral gap of connected quartic graph on $n$ vertices is $(1+o(1))\frac{4\pi^2}{n^2}$. From this result, the Aldous--Fill conjecture follows for $k=4$.Comment: 28 pages. arXiv admin note: text overlap with arXiv:1907.0373

International political economy and its implications

International political economy as a science that connected economics and politics and state a different perspective about the classical conception in economic matters, in the sense that, with a lack of belief in the invisible hand of Adam Smith in the regulation of markets and prices, belie vest hat government should in terrene in economic and trade activity to cause and prosperity of the economy and international trade. In this context, because of the economic activities more organize dandy avoid the chaos, should there be a hegemonic power to maintain order and to confront and deal with possible abuse by governments that are trying to take advantage of the benefits and opportunities and hithermost beneficial while close their markets to others. This paper is to study the difference and common a laities between neoclassical economics and international political economy and government interference in the economy, regime theory, and also the theory of hegemonic stability, and hegemonic actions in its global roles stabilizing factor in international markets and economies, also to answer to the questions that whether all government scan expander benefit the free market, or not an whether Iran as a developing country how can benefit from opportunity obtained in this direction, and to be consistent with integration of the global economy

The essential role of hippocampo-cortical connections in temporal coordination of spindles and ripples

The predominant activity of slow wave sleep is cortical slow oscillations (SOs), thalamic spindles and hippocampal sharp wave ripples. While the precise temporal nesting of these rhythms was shown to be essential for memory consolidation, the coordination mechanism is poorly understood. Here we develop a minimal hippocampo-cortico-thalamic network that can explain the mechanism underlying the SO-spindle-ripple coupling indicating of the succession of regional neuronal interactions. Further we verify the model predictions experimentally in naturally sleeping rodents showing our simple model provides a quantitative match to several experimental observations including the nesting of ripples in the spindle troughs and larger duration but lower amplitude of the ripples co-occurring with spindles or SOs compared to the isolated ripples. The model also predicts that the coupling of ripples to SOs and spindles monotonically enhances by increasing the strength of hippocampo-cortical connections while it is stronger at intermediate values of the cortico-hippocampal projections

Cytotoxicity of a New Nano Zinc-Oxide Eugenol Sealer on Murine Fibroblasts

Introduction: The aim of this study was to evaluate the cytotoxicity of a new nano zinc-oxide eugenol (NZOE) sealer in comparison with AH-26 and Pulpdent root canal sealers. Methods and Materials: The L929 mouse fibroblast cells were cultivated and incubated for 24, 48 or 72 h with different dilutions (1/1, 1/2, 1/4, 1/8, 1/16 and 1/32) of culture media previously exposed to either of the test sealers naming NZOE, AH-26 or Pulpdent. At the end of incubation period, the effect of sealers on cell viability was evaluated using Mosmann’s Tetrazolium Toxicity (MTT) colorimetric assay. The data was compared using the one-way analysis of variance (ANOVA) followed by the Tukey’s post hoc test for multiple comparisons. Results: After 24, 48 or 72 h, both NZOE and Pulpdent sealers inhibited cell viability at 1/1, 1/2 and 1/8 dilutions. Within the 24 and 48 h, the AH-26 sealer reduced the cell viability at all dilutions except the 1/32 solution; however after 72 h even the 1/32 dilution was cytotoxic. Conclusion: The biocompatibility of the nano zinc-oxide eugenol sealer was comparable to Pulpdent sealer and lower than AH-26.Keywords: Cytotoxicity; MTT Assay; Nanoparticles; Root Canal Sealer; Zinc-Oxide Eugenol

In Vitro Cytotoxicity of a New Nano Root Canal Sealer on Human Gingival Fibroblasts

Introduction: The aim of this in vitro study was to evaluate the cytotoxicity of a new nano zinc-oxide eugenol (NZOE) sealer on human gingival fibroblasts (HGFs) compared with Pulpdent (micro-sized ZOE sealer) and AH-26 (resin-based sealer). Methods and Materials: The Pulpdent, AH-26, and NZOE sealers were prepared and exposed to cell culture media immediately after setting, and 24 h and one week after setting. Then, the primary cultured HGFs were incubated for 24 h with different dilutions (1:1 to 1:32) of each sealer extract. Cell viability was evaluated by methyl thiazolyl diphenyl tetrazolium bromide (MTT) assay. The results were compared using two-way analysis of variance followed by Tukey’s post hoc test. The level of significance was set at 0.05. Results: All sealer extracts, up to 32 times dilutions, showed cytotoxicity when exposed to HGF immediately after setting. The extracts obtained 24 h or one week after setting showed lower cytotoxicity than extracts obtained immediately after setting. At all setting times, NZOE showed lower cytotoxicity than Pulpdent and AH-26. While one-week extracts of NZOE had no significant effect on the viability of HGF at dilutions 1:4 to 1:32, both Pulpdent and AH-26 decreased the cell viability at dilutions of 1:4 and 1:8. Conclusion: NZOE exhibited lower cytotoxicity compared to Pulpdent and AH-26 on HGF and has the potential to be considered as a new root canal filling material.Keywords: Cytotoxicity; Human Gingival Fibroblast; MTT assay; Nano; Seale

The factor structure of 36-Item Short Form Survey among patients with type 2 diabetes

BACKGROUND: Quality of life is one of the most important issues in patients with type 2 diabetes mellitus (T2DM). Although some studies examined the quality of life in these patients, most of them are related to descriptive statistics. It is essential to address measurement assessment to assess the quality of life among patients with T2DM. Therefore, this study aimed to examine the factor structure of the 36-Item Short Form Survey (SF-36) among patients with T2DM. METHODS: This study was conducted using convenience sampling in Tehran and Mashhad, Iran, from 2019 to 2020. In this psychometric study, the SF-36, according to Kline’s approach, was administered among 290 patients with T2DM. The factor structure of the scales was assessed. To examine factor structure, we examined exploratory and confirmatory factor analysis. Besides, the reliability of the questionnaire was assessed via Cronbach’s alpha and split-half. In sum, to analyze the data, SPSS software was used. RESULTS: By examining the Promax matrix, the SF-36 resulted in a six-factor structure; however, the items of one of the factors were removed due to cross-loading (0.51-0.53). According to the findings of exploratory factor analysis in 5 factors, Cronbach’s alpha coefficients ranged from 0.73 to 0.97 and split-half ranged from 0.60 to 0.97. CONCLUSION: The findings revealed that the five-factor model of the SF-36 had satisfactory validity and reliability. Thus, this questionnaire can be used in future studies to assess the quality of life of patients with T2DM

A Psychoanalytic Review of ‘Endgame’

While this play can be analyzed from different aspects, the psychological aspect has an important contribution to the theme of play. According to different schools characters can be considered the outcome of different forces ; in Marxist view they are products of cultural, economic and ideological forces; according to Darwin and naturalistic views human are outcome of natural selection; according to Freud and Lacan current situation of human are determined by their past, memories, the way they have been brought up, language and whatever characterized their past.In this play there are some references and evidences that support what have said above. Hamm, Clov, Nagg and Nelly are the characters to whom their past are significant. The role of unconscious and its effects on conscious, the repression of their desires, their melancholic response to what has been lost, the master/ slave relationships, the interpretation of dreams, the feeling of abondinment and their relationships to the theme of the play are all aspects that can be examined psychoanalytically in this play

A Psychoanalytic Review of ‘Endgame’

While this play can be analyzed from different aspects, the psychological aspect has an important contribution to the theme of play. According to different schools characters can be considered the outcome of different forces ; in Marxist view they are products of cultural, economic and ideological forces; according to Darwin and naturalistic views human are outcome of natural selection; according to Freud and Lacan current situation of human are determined by their past, memories, the way they have been brought up, language and whatever characterized their past.In this play there are some references and evidences that support what have said above. Hamm, Clov, Nagg and Nelly are the characters to whom their past are significant. The role of unconscious and its effects on conscious, the repression of their desires, their melancholic response to what has been lost, the master/ slave relationships, the interpretation of dreams, the feeling of abondinment and their relationships to the theme of the play are all aspects that can be examined psychoanalytically in this play

A Marxist Reading of ‘The Madwoman of Chaillot’

Having read the play, it could be understood that ideology and capitalistic attitude which is a recent phenomenon has been spread throughout the world and people have a materialistic view towards and commodify each other. The use and exchange values are replaced by sign exchange value and commodity and goods are changing into master and humanity becomes their slave. Hence commodity fetishism is the new aspect of economic relations. Moreover by means of anarchy and chaos and also unawareness of lower class or proletariats, capitalists can get what they want. However the Marxist theory and reading of the play reveals that finally the proletariats of a society come to consciousness of their being abused by capitalism and revolt against them and live a free life ever after as Marx had predicted it in nineteenth century. In spite of his prediction, this fantasy never comes true in reality and it remains as a fairy tale and that is why this work is categorized in genre of fantasy. Nonetheless analysis of this play from different perspective can show how it is possible