Износостойкость высокохромистых чугунов при ударном помоле абразива в присутствии коррозионно-активной среды

Представлены результаты испытаний чугунов, содержащих 2,24-2,59 % С, 2,07-3,13 % Mn и 9,7-28,4 % Cr, в условиях ударно-абразивного изнашивания в присутствии водных растворов щелочи и кислоты с варьированием рН от 14 до 1. Показано, что износ чугунов меняется в зависимости от рН раствора немонотонно, а характер влияния хрома на износ зависит от типа пульпы. Установлено, что чугуны с 20–28 % Cr в данных условиях изнашивания не имеют преимущества перед менее легированными хромом чугунами. В пульпе с резко кислой средой (рН=1) износ чугунов растет прямо пропорционально содержанию в них хрома.Представлено результати випробувань чавунів, що містять 2,24-2,59 % С, 2,07-3,13 % Mn і 9,7-28,4 % Cr, в умовах ударно-абразивного зношування в присутності водяних розчинів луги і кислоти з варіюванням рН від 14 до 1. Показано, що знос чавунів змінюється в залежності від рН розчину немонотонно, а характер впливу хрому на знос залежить від типу пульпи. Встановлено, що чавуни з 20-28 % Cr у даних умовах зношування не мають переваги перед менш легованими хромом чавунами. У пульпі з різко кислим середовищем (рН=1) знос чавунів зростає прямо пропорційно вмісту в них хрому.The results of the test cast iron, containing 2,24-2,59 % С, 2,07-3,13 % Mn and 9,7-28,4 % Cr, in condition is striking-abrasive wear in water solutions of alkali and acids with variation pH from 14 to 1 are presented. It is shown that wear of cast irons is changing depending on pH solution nonmonotonic, but nature of the influence of chromium on wear depends on type of the pulp. It is determined that cast irons with 20-28 % Cr in wear condition mentioned above has no advantage over cast irons with 10-12 % Cr. In pulp with sharply tart ambience (pH=1) wear of cast irons grows straight pro rata contents of chromium

Quantificação de fatores de crescimento na pele de equinos tratada com plasma rico em plaquetas

O plasma rico em plaquetas (PRP) é um produto derivado da centrifugação do sangue total, sendo rico em fatores bioativos, como os de crescimento. Apesar da ampla utilização em processos cicatriciais, há controvérsia sobre a eficácia da terapia na cicatrização cutânea. O objetivo desse estudo foi quantificar e comparar a concentração dos fatores TGF-β1 e PDGF-BB no PRP, plasma sanguíneo e pele, durante diferentes fases do processo de cicatrização da pele tratada ou não com PRP. Foram utilizados sete equinos machos castrados, mestiços, hígidos, com idade entre 16 e 17 (16,14±0,63) anos. Três lesões em formato quadrangular (6,25cm²) foram produzidas cirurgicamente nas regiões glúteas direita e esquerda de todos os animais. Doze horas após indução das feridas, 0,5mL do PRP foi administrado em cada uma das quatro extremidades das feridas de uma das regiões glúteas (Grupo tratado = GT), escolhida aleatoriamente. A região contralateral foi utilizada como controle (GC). As feridas foram submetidas à limpeza diária com água Milli Q, e amostras foram obtidas mediante biópsias realizadas com Punch de 6mm. Foram obtidas seis biópsias de pele, sendo a primeira realizada logo após a produção da ferida (T0), e as demais com 1 (T1) 2 (T2) 7 (T3) e 14 (T4) dias após a indução da lesão. A sexta biópsia (T5) foi obtida após completo fechamento da pele, que ocorreu aproximadamente aos 37 dias (36,85±7,45, GC; 38,85±6,46, GT). Também foram obtidas amostras de sangue com EDTA em todos os tempos mencionados. A quantificação dos fatores de crescimento TGF-β1 e PDGF-BB na pele, PRP e plasma sanguíneo foi realizada pela técnica ELISA. Os dados foram analisados estatisticamente pelo teste t, correlação de Pearson e regressão, utilizando nível de significância de 5%. Não houve diferença entre os grupos, nos valores dos dois fatores de crescimento mensurados na pele, nos diferentes tempos. Também não houve correlação entre a quantidade dos fatores de crescimento presentes na pele e no plasma. Por outro lado, correlação positiva foi observada entre PRP e pele no grupo tratado, para os fatores de crescimento TGF-β1 (r=0,31) e PDGF-BB (r=0,38), bem como entre ambos os fatores de crescimento presentes no PRP (r=0,81). Considerando as concentrações dos fatores de crescimento no T0, os maiores valores cutâneos (p<0,05) do TGF-β1, em ambos os grupos, ocorreram nos tempos T3 e T5. Valores mais elevados (p<0,05) do PDGF-BB ocorreram no T4 (GT) e T5 (GC). No plasma não houve alteração nas concentrações desses fatores em relação ao T0, o que sugere que o PRP não acarreta efeito sistêmico, quando os procedimentos adotados na presente pesquisa são utilizados. A administração local de PRP no volume estudado, 12 h após indução cirúrgica de ferida cutânea na região glútea de equinos não ocasiona maiores concentrações dos fatores de crescimento TGF-β1 e PDGF-BB no plasma sanguíneo e pele, durante o processo de cicatrização

jtextor/2020-ctl-killing: Initial release

Version of code generating the analyses that are included in the manuscript. Copyright: Open Acces

jtextor/2020-ctl-killing: Initial release

Version of code generating the analyses that are included in the manuscript. Copyright: Open Acces

Crawling and Gliding: A Computational Model for Shape-Driven Cell Migration

Contains fulltext : 152083.PDF (publisher's version ) (Open Access)Cell migration is a complex process involving many intracellular and extracellular factors, with different cell types adopting sometimes strikingly different morphologies. Modeling realistically behaving cells in tissues is computationally challenging because it implies dealing with multiple levels of complexity. We extend the Cellular Potts Model with an actin-inspired feedback mechanism that allows small stochastic cell rufflings to expand to cell protrusions. This simple phenomenological model produces realistically crawling and deforming amoeboid cells, and gliding half-moon shaped keratocyte-like cells. Both cell types can migrate randomly or follow directional cues. They can squeeze in between other cells in densely populated environments or migrate collectively. The model is computationally light, which allows the study of large, dense and heterogeneous tissues containing cells with realistic shapes and migratory properties

Artistoo, a library to build, share, and explore simulations of cells and tissues in the web browser

Contains fulltext : 233834.pdf (Author’s version preprint ) (Closed access) Contains fulltext : 233834.pdf (Publisher’s version ) (Open Access

Interpreting T-cell search "strategies" in the light of evolution under constraints

Two decades of in vivo imaging have revealed how diverse T-cell motion patterns can be. Such recordings have sparked the notion of search "strategies": T cells may have evolved ways to search for antigen efficiently depending on the task at hand. Mathematical models have indeed confirmed that several observed T-cell migration patterns resemble a theoretical optimum; for example, frequent turning, stop-and-go motion, or alternating short and long motile runs have all been interpreted as deliberately tuned behaviours, optimising the cell's chance of finding antigen. But the same behaviours could also arise simply because T cells cannot follow a straight, regular path through the tight spaces they navigate. Even if T cells do follow a theoretically optimal pattern, the question remains: which parts of that pattern have truly been evolved for search, and which merely reflect constraints from the cell's migration machinery and surroundings? We here employ an approach from the field of evolutionary biology to examine how cells might evolve search strategies under realistic constraints. Using a cellular Potts model (CPM), where motion arises from intracellular dynamics interacting with cell shape and a constraining environment, we simulate evolutionary optimization of a simple task: explore as much area as possible. We find that our simulated cells indeed evolve their motility patterns. But the evolved behaviors are not shaped solely by what is functionally optimal; importantly, they also reflect mechanistic constraints. Cells in our model evolve several motility characteristics previously attributed to search optimisation-even though these features are not beneficial for the task given here. Our results stress that search patterns may evolve for other reasons than being "optimal". In part, they may be the inevitable side effects of interactions between cell shape, intracellular dynamics, and the diverse environments T cells face in vivo

Local Fit Evaluation of Structural Equation Models Using Graphical Criteria

Contains fulltext : 190024.pdf (Publisher’s version ) (Open Access

Local Attachment Explains Small World-like Properties of Fibroblastic Reticular Cell Networks in Lymph Nodes

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Editorial: Methods and Applications of Computational Immunology

Contains fulltext : 215786.pdf (publisher's version ) (Open Access