Формирование покрытий на основе нитрида титана из вакуумного дугового разряда для защиты конструкционных материалов от водородного охрупчивания

Покрытия из нитрида титана применяется в качестве защитных покрытий, благодаря своей износостойкости, твердости и химической стабильности. Все чаще эти покрытия используются как защитный барьер от проникновения водорода и водородного охрупчивания. Циркониевые сплавы представляются себя широкие применения: насосы и трубозапорная арматура, работающая в условиях воздействия агрессивных сред, материалы ядерной энергетики (ТВЭЛ), биомедицинские имплантаты и т. д.Titanium nitride coatings are used as protective coatings due to their wear resistance, hardness and chemical stability. Increasingly, these coatings are used as a protective barrier against hydrogen penetration and hydrogen embrittlement. Zirconium alloys appear to be of widespread use: pumps and pipe fittings operating in aggressive environments, nuclear energy materials (TVEL), biomedical implants, etc

Activation of Regulatory T Cells during Inflammatory Response Is Not an Exclusive Property of Stem Cells

BACKGROUND: Sepsis and systemic-inflammatory-response-syndrome (SIRS) remain major causes for fatalities on intensive care units despite up-to-date therapy. It is well accepted that stem cells have immunomodulatory properties during inflammation and sepsis, including the activation of regulatory T cells and the attenuation of distant organ damage. Evidence from recent work suggests that these properties may not be exclusively attributed to stem cells. This study was designed to evaluate the immunomodulatory potency of cellular treatment during acute inflammation in a model of sublethal endotoxemia and to investigate the hypothesis that immunomodulations by cellular treatment during inflammatory response is not stem cell specific. METHODOLOGY/PRINCIPAL FINDINGS: Endotoxemia was induced via intra-peritoneal injection of lipopolysaccharide (LPS) in wild type mice (C3H/HeN). Mice were treated with either vital or homogenized amniotic fluid stem cells (AFS) and sacrificed for specimen collection 24 h after LPS injection. Endpoints were plasma cytokine levels (BD™ Cytometric Bead Arrays), T cell subpopulations (flow-cytometry) and pulmonary neutrophil influx (immunohistochemistry). To define stem cell specific effects, treatment with either vital or homogenized human-embryonic-kidney-cells (HEK) was investigated in a second subset of experiments. Mice treated with homogenized AFS cells showed significantly increased percentages of regulatory T cells and Interleukin-2 as well as decreased amounts of pulmonary neutrophils compared to saline-treated controls. These results could be reproduced in mice treated with vital HEK cells. No further differences were observed between plasma cytokine levels of endotoxemic mice. CONCLUSIONS/SIGNIFICANCE: The results revealed that both AFS and HEK cells modulate cellular immune response and distant organ damage during sublethal endotoxemia. The observed effects support the hypothesis, that immunomodulations are not exclusive attributes of stem cells

Percentage of regulatory T cells after AFS cell application.

<p>The percentage of Foxp3⁺ lymphocytes was significantly increased in the pool of CD4⁺CD25⁺ lymphocytes after application of homAFS compared to saline-treated positive-controls (+) and non-endotoxemic negative-controls (−).</p

Pulmonary PMN infiltration after HEK cell application.

<p>Pulmonary infiltration with PMNs was significantly increased in positive controls (+) and homHEK (p<0.05 vs. [−]) treated endotoxemic mice compared to negative-controls (−) 24 h after LPS injection. Mice treated with vitHEK cells showed significantly decreased pulmonary neutrophil influx compared to positive-controls (+) and homHEK treated endotoxemic mice.</p

Preparation of vital AFS cells and homogenized AFS cells.

<p>10⁶ vital AFS cells (vitAFS) were prepared in 0.7 ml sterile phosphate buffered saline (PBS) for intraperitoneal injection in mice randomly assigned to the vitAFS group (2 h after LPS challenge). For the preparation of homogenized AFS cells, 10⁶ vital AFS cells underwent 5 min cell-disruption in 0.7 ml PBS prior to injection by sonication.</p

Mouse model of sublethal endotoxemia (study design).

<p>Male C3H/HeN mice were randomly assigned to either application of vital AFS cells (vitAFS), homogenized AFS cells (homAFS) or saline only (positive-control). Sublethal endotoxemia was induced by intraperitoneal injection of LPS. Mice distributed to the vitAFS group received 10⁶ vital AFS cells in 0.7 ml sterile phosphate buffered saline (PBS) intraperitoneally 2 h after LPS challenge. The same amount of cells and PBS was used for treatment of the homAFS group, but prior to injection vital cells were disrupted using the Sonopulse cell disperser (BANDELIN electronic, Berlin, Germany). The positive-control group received 0.7 ml sterile PBS without cells or disrupted cell material. Mice were sacrificed 24 h after LPS challenge and blood as well as tissue specimens were harvested. A group of 6 animals was sacrificed without any treatment (negative-control) to determine basal cytokine levels, T-cell subtype populations and lung polymorphonuclear neutrophil (PMN) infiltration.</p

IL-2 plasma levels after HEK application.

<p>The IL-2 plasma levels were significantly increased in the group treated with vitHEK compared to saline-treated positive-controls (+).</p

Plasma cytokine response 24 h after LPS challenge (AFS cells).

*<p>p<0.05 vs. Control.</p

Percentage of regulatory T cells after HEK cell application.

<p>Relative expression of Foxp3 in CD4⁺CD25⁺ lymphocytes was significantly increased in the group treated with vitHEK cells compared to endotoxemic mice, which received homHEK cells, saline-treated positive-controls (+) and non-endotoxemic negative-controls (−).</p

Pulmonary PMN infiltration after AFS cell application.

<p>Pulmonary infiltration with PMNs was significantly increased in positive-controls (+) compared to negative-controls (−) 24 h after LPS injection. Mice treated with hom AFS cells showed significantly decreased pulmonary neutrophil influx compared to positive-controls (+).</p