Pour voir les autres types de publications sur ce sujet consultez le lien suivant : Plasma activation grafting.
Articles de revues sur le sujet « Plasma activation grafting »
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 50 meilleurs articles de revues pour votre recherche sur le sujet « Plasma activation grafting ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les articles de revues sur diverses disciplines et organisez correctement votre bibliographie.
1
Chang, Juu En, Yi Kuo Chang, Min Her Leu, Ying Liang Chen et Jing Hong Huang. « Application of Ambient-Temperature Argon Plasma Modified PET Fibers with Surface Grafting for Heavy Metal Removal ». Advanced Materials Research 978 (juin 2014) : 153–56. http://dx.doi.org/10.4028/www.scientific.net/amr.978.153.
Texte intégralRésumé :
The present study utilized the capability of ambient-temperature plasma in modifying the surface properties of materials to activate the polyethylene terephthalate (PET) fiber surfaces. The effects of different plasma treatment parameters (such as plasma power, treatment time) and grafting parameters (such as grafting temperature, acrylic acid monomer concentration, grafting time) on the activation and grafting of the PET fibers were studied. The feasibility of applying ambient-temperature plasma combined with grafting technology for the preparation of ion exchangers in the heavy metal containing wastewater treatment was evaluated.
2
Das, B. « Cold plasma activation and silane grafting on a moving fiber glass bundle* ». Journal of Adhesion Science and Technology 10, no 12 (janvier 1996) : 1371–82. http://dx.doi.org/10.1163/156856196x00300.
Texte intégral
3
Alonso, Janaína G., Carla Dalmolin, Jacimar Nahorny, Abel A. C. Recco, Luis C. Fontana et Daniela Becker. « Active screen plasma system applied to polymer surface modification : poly(lactic acid) surface activation before polyaniline graft polymerization in aqueous medium ». Journal of Polymer Engineering 38, no 8 (28 août 2018) : 795–802. http://dx.doi.org/10.1515/polyeng-2017-0298.
Texte intégralRésumé :
Abstract An active screen plasma system (ASPS) was used for the surface activation of poly(lactic acid) (PLA) as a pretreatment before the oxidative graft polymerization of polyaniline (PANI). In ASPS, the plasma glow discharge occurs outside the grid, and the samples to be treated are placed inside the cage where they are subjected to a floating potential (about −12 V). An increase in hydrophilicity was observed for all samples after Ar plasma treatment. In addition, a decrease in thermal stability and changes in crystallization behavior were observed for PLA samples treated for a longer time. After PANI graft polymerization, smoothing of the surface topography was noticed in samples treated for short time periods. Such a change in the topography, in addition to surface activation, provides better conditions for subsequent PANI grafting.
4
Shalaby, Marwa S., Heba Abdallah, Ralph Wilken, Schmüser Christoph et Ahmed M. Shaban. « Surface Treatment by Physical Irradiation for Antifouling, Chlorine-Resistant RO Membranes ». Membranes 13, no 2 (13 février 2023) : 227. http://dx.doi.org/10.3390/membranes13020227.
Texte intégralRésumé :
Reverse osmosis (RO) membranes represent a strategic tool for the development of desalination and water treatment processes. Today’s global needs for clean water supplies show stressing circumstances to secure this supply, relying upon desalination and wastewater treatment and reuse, especially in Egypt and the Middle East. However, chlorine attack and fouling of polyamide layers, the active (selective) layers of RO membranes, are representing a great obstacle to seriously spreading the use of this technology. One promising way of fouling control and chlorine resistance is surface modification using grafting by plasma or vacuum ultraviolet (VUV) irradiation as a layer-by-layer assembly on polyamide membranes. Several studies have shown the effect of grafting by plasma using methacrylic acid (atmospheric pressure plasma) and showed that grafted coatings can improve PA membranes toward permeation compared with commercial ones with fouling behavior but not chlorine resistance. In this work, the techniques of layer-by-layer (LBL) assembly for previously prepared PA RO membranes (3T) using a mixed-base polymer of polysulfone and polyacrylonitrile in the presence of nanographene oxide (GO) without chemical grafting and with chemically grafted poly-methacrylic acid (3TG) were used. Membranes 3T, 3TG, a blank one (a base polymer membrane only was surface modified using VUV activation (AKT), and one with a grafted layer with polyethylene glycol (VUV-PEG) were prepared. These were then compared with polydimethylsiloxane (VUV-PDMS) and another surface modification with low-pressure plasma using acrylic acid (acryl) and hexadimethyl siloxane (GrowPLAS). The tested membranes were evaluated by short-term permeation and salt rejection experiments together with fouling behavior and chlorine resistance. A clear improvement of chlorine resistance and antifouling was observed for 3T membranes under plasma treatment, especially with the grafting with polyacrylic acid. Better antifouling and antichlorine behaviors were achieved with the vacuum UV treatment.
5
Hoel, Tom N., Vibeke Videm, Tom E. Mollnes, Kjell Saatvedt, Frank Brosstad, Arnt E. Fiane, Erik Fosse et Jan L. Svennevig. « Off-pump cardiac surgery abolishes complement activation ». Perfusion 22, no 4 (juillet 2007) : 251–56. http://dx.doi.org/10.1177/0267659107084142.
Texte intégralRésumé :
Background. This prospective randomized study compared the inflammatory response in patients undergoing elective on-pump and off-pump coronary artery bypass grafting. Patients and methods. Forty-four patients undergoing elective coronary artery bypass grafting were recruited with 22 patients randomized to on-pump heart surgery and 22 patients to off-pump coronary bypass surgery. Plasma levels of C3bc, the terminal SC5b-9 complement complex, myeloperoxidase, β -thromboglobulin and prothrombin fragment F1 + 2 were measured before the operation, intraoperatively, at termination of the operation, and two hours post-operatively. Results. Complement was markedly activated in the on-pump group as indicated by a significant increase in C3bc and SC5b-9 (p < 0.001 for both), whereas no complement activation was seen in the off-pump group (p = 0.001 between the groups). In contrast, both groups showed significant activation of neutrophils, platelets and coagulation, as indicated by an early increase in myeloperoxidase and a post-operative increase in β-thromboglobulin and F1 + 2, respectively. Notably, there were no inter-group differences with regard to neutrophil and platelet activation, whereas coagulation activation was more pronounced in the off-pump group (p < 0.01). Conclusions. Off-pump surgery completely eliminated the heart-lung machine-induced complement activation. Neutrophils and platelets were equally activated in both groups, whereas coagulation was enhanced post-operatively in the off-pump group. Perfusion (2007) 22, 251—256.
6
Medvedeva, E. A., L. G. Gelis, V. V. Shumavets et I. I. Russkikh. « CLINICAL OUTCOMES AND DYNAMICS OF PLATELET-PLASMA AND VASCULAR HEMOSTASIS IN PATIENTS WITH UNSTABLE ANGINA AND CORONARY ARTERY BYPASS GRAFTING ». Eurasian heart journal, no 1 (28 février 2021) : 78–86. http://dx.doi.org/10.38109/2225-1685-2021-1-78-86.
Texte intégralRésumé :
The aim. To evaluate the clinical outcomes and features of the state of the platelet-plasma and vascular hemostasis in patients (pts) with unstable angina and coronary artery bypass grafting (CABG) on-pump and off-pump for the correction of antithrombotic therapy and reduce the number of postoperative cardiovascular events. Material and methods. The study included 146 pts with unstable angina (UA) with a surgical treatment strategy. CG amounted to 106 pts with CABG and a standard approach to drug maintenance. MG comprised 40 pts with CABG and a personalized approach to antithrombotic therapy. Results. In CABG off-pump in pts with UA, an increased in platelet aggregation and activation of platelet hemostasis occurs on the 2nd day of the postoperative period, in CABG on-pump on the 5-7th day. Activation of plasma hemostasis had laboratory manifestations on the 5-7th day of the postoperative period, and is most pronounced in CABG on-pump, compared with CABG off-pump. After 1 month of control, 38,7% pts with UA and CABG were characterized by the presence of high residual platelet reactivity against the background of standard antiplatelet treatment, of which 23,6% retained activation of plasma hemostasis, which is manifested in excess of the normal level of D-dimers, as well as an increased in peak thrombin concentration and endogenous thrombin potential. Patients with UA and CABG who underwent correction of antithrombotic therapy differed from patients with a standard approach to treatment with a significantly lower number of repeated cardiovascular events over 2 years of follow-up (5% versus 22.6%).
7
Singh, Sukhdeep, Patrick Mai, Justyna Borowiec, Yixin Zhang, Yong Lei et Andreas Schober. « Donor–acceptor Stenhouse adduct-grafted polycarbonate surfaces : selectivity of the reaction for secondary amine on surface ». Royal Society Open Science 5, no 7 (juillet 2018) : 180207. http://dx.doi.org/10.1098/rsos.180207.
Texte intégralRésumé :
Donor–acceptor Stenhouse adducts (DASAs) are gaining attention from organic and material chemists due to their visible light-stimulated photochromic properties. In this report, we present a facile method for grafting coloured triene on polycarbonate surface, without involving any pre-treatments like plasma activation, etc. The chemoselectivity of carbonate with a primary amine and Meldrum's activated furan (MAF) with polymer bound secondary amine has been exploited to graft photoswitchable DASA on the polymer surface. Primary, secondary and tertiary amine-functionalized polycarbonate surfaces have been prepared to evaluate the reactivity of amine with MAF.
8
Asadian, Mahtab, Ke Vin Chan, Mohammad Norouzi, Silvia Grande, Pieter Cools, Rino Morent et Nathalie De Geyter. « Fabrication and Plasma Modification of Nanofibrous Tissue Engineering Scaffolds ». Nanomaterials 10, no 1 (8 janvier 2020) : 119. http://dx.doi.org/10.3390/nano10010119.
Texte intégralRésumé :
This paper provides a comprehensive overview of nanofibrous structures for tissue engineering purposes and the role of non-thermal plasma technology (NTP) within this field. Special attention is first given to nanofiber fabrication strategies, including thermally-induced phase separation, molecular self-assembly, and electrospinning, highlighting their strengths, weaknesses, and potentials. The review then continues to discuss the biodegradable polyesters typically employed for nanofiber fabrication, while the primary focus lies on their applicability and limitations. From thereon, the reader is introduced to the concept of NTP and its application in plasma-assisted surface modification of nanofibrous scaffolds. The final part of the review discusses the available literature on NTP-modified nanofibers looking at the impact of plasma activation and polymerization treatments on nanofiber wettability, surface chemistry, cell adhesion/proliferation and protein grafting. As such, this review provides a complete introduction into NTP-modified nanofibers, while aiming to address the current unexplored potentials left within the field.
9
Wahba, Alexander, Gregor Black, Mario Koksch, Gregor Rothe, Jürgen Preuner, Gred Schmitz et Dietrich E. Bimbaum. « Aprotinin Has no Effect on Platelet Activation and Adhesion during Cardiopulmonary Bypass ». Thrombosis and Haemostasis 75, no 05 (1996) : 844–48. http://dx.doi.org/10.1055/s-0038-1650377.
Texte intégralRésumé :
SummaryAprotinin reduces blood loss following cardiopulmonary bypass operations (CPB) by the prevention of hyperfibrinolysis. Its influence on circulating platelets is uncertain. In this prospective trial we investigated activation, adhesion, and aggregation receptors on the platelet surface in 20 patients who underwent elective coronary artery bypass grafting. These patients were randomly assigned to receive either a high dose of aprotinin or placebo. Flow cytometry was performed to determine platelet activation [P-selectin, glycoprotein (GP) 53], adhesive (GP Ib), and aggregatory (GP IIb-IIIa) receptors on circulating platelets, before, during, and after CPB. Aprotinin had neither a significant effect on platelet activation nor on adhesive and aggregatory receptors. Plasma levels of D-dimers were measured before and after CPB to assess fibrinolytic activity. D-dimers following CPB and chest tube drainage were significantly less in the aprotinin group. We conclude that aprotinin reduces blood loss by its effect on fibrinolysis but has no direct influence on platelet function.
10
Černáková, L’, D. Kováčik, A. Zahoranová, M. Černák et M. Mazúr. « Surface Modification of Polypropylene Non-Woven Fabrics by Atmospheric-Pressure Plasma Activation Followed by Acrylic Acid Grafting ». Plasma Chemistry and Plasma Processing 25, no 4 (août 2005) : 427–37. http://dx.doi.org/10.1007/s11090-004-3137-4.
Texte intégral
11
Permyakova, Elizaveta S., Liubov Yu Antipina, Philipp V. Kiryukhantsev-Korneev, Andrey M. Kovalskii, Josef Polčak, Anton Manakhov, Kristina Yu Gudz, Pavel B. Sorokin et Dmitry V. Shtansky. « Plasma Surface Polymerized and Biomarker Conjugated Boron Nitride Nanoparticles for Cancer-Specific Therapy : Experimental and Theoretical Study ». Nanomaterials 9, no 12 (21 novembre 2019) : 1658. http://dx.doi.org/10.3390/nano9121658.
Texte intégralRésumé :
A new low-pressure plasma-based approach to activate the surface of BN nanoparticles (BNNPs) in order to facilitate the attachment of folate acid (FA) molecules for cancer-specific therapy is described. Plasma treatment of BNNPs (BNNPsPT) was performed in a radiofrequency plasma reactor using ethylene and carbon dioxide monomers. The carboxyl groups deposited on the surface of BNNPsPT were activated by N,N’-dicyclohexylcarbodiimide (DCC) and participated in the condensation reaction with ethylene diamine (EDA) to form a thin amino-containing layer (EDA-BNNPPT). Then, the DCC-activated FA was covalently bonded with BNNPsPT by a chemical reaction between amino groups of EDA-BNNPsPT and carboxyl groups of FA. Density functional theory calculations showed that the pre-activation of FA by DCC is required for grafting of the FA to the EDA-BNNPsPT. It was also demonstrated that after FA immobilization, the electronic characteristics of the pteridine ring remain unchanged, indicating that the targeting properties of the FA/EDA-BNNPsPT nanohybrids are preserved.
12
Casati, Valter, Chiara Gerli, Annalisa Franco, Patrizia Della Valle, Stefano Benussi, Ottavio Alfieri, Giorgio Torri et Armando D’Angelo. « Activation of Coagulation and Fibrinolysis during Coronary Surgery ». Anesthesiology 95, no 5 (1 novembre 2001) : 1103–9. http://dx.doi.org/10.1097/00000542-200111000-00013.
Texte intégralRésumé :
Background The authors studied the changes in selected hemostatic variables in patients undergoing coronary surgery with on-pump coronary artery bypass grafting (CABG) or off-pump coronary artery bypass surgery (OPCAB) techniques. Methods Platelet counts and plasma concentrations of antithrombin, fibrinogen, D dimer, alpha(2) antiplasmin, and plasminogen were measured preoperatively, 5 min after administration of heparin, 10 min after arrival in the intensive care unit, and 24 h after surgery in patients scheduled to undergo OPCAB (n = 15) or CABG (n = 15). To correct for dilution, hemostatic variables and platelet counts were adjusted for the changes in immunoglobulin G plasma concentrations and hematocrit, respectively. Results Adjusting for dilution, antithrombin and fibrinogen concentrations decreased to a similar extent in patients undergoing OPCAB or CABG (pooled means and 95% confidence limits of the mean: 95.5% of baseline, 93-98%, P = 0.002, and 91.7% of baseline, 88-95%, P = 0.0001), respectively, whereas alpha(2)-antiplasmin concentrations were unchanged. Only CABG was associated with a reduction in platelet counts (76% of baseline, 66-85%, P = 0.0001), plasminogen concentrations (96% of baseline, 91-99%, P = 0.011), and increased D-dimer formation (476%, 309-741%, P = 0.004). Twenty-four hours after surgery, platelet counts were still lower in patients undergoing CABG (P = 0.049), but all the investigated variables adjusted for dilution were similar in the two groups. Conclusions Coronary surgery causes a net consumption of antithrombin and fibrinogen. A transient decrease in platelet counts, with plasminogen activation and increased D-dimer formation, however, is only observed with CABG. Twenty-four hours after surgery, the hemostatic profiles of patients in both groups are similar.
13
Coates, Don M., et Stephen L. Kaplan. « Modification of Polymeric Surfaces With Plasmas ». MRS Bulletin 21, no 8 (août 1996) : 43–45. http://dx.doi.org/10.1557/s0883769400035703.
Texte intégralRésumé :
As adaptable as polymeric materials are in their many applications to our daily lives, the need exists to tailor the polymer surfaces to provide even more flexibility in regard to their uses. Plasma treatments offer an unprecedented spectrum of possible surface modifications to enhance polymers, ranging from simple topographical changes to creation of surface chemistries and coatings that are radically different from the bulk polymer. Furthermore plasma treatments are environmentally friendly and economical in regard to their use of materials.Plasma processing can be classified into at least four categories that often overlap. These are the following: (1) surface preparation by breakdown of surface oils and loose contaminates, (2) etching of new topographies, (3) surface activation by creation or grafting of new functional groups or chemically reactive, excited metastable species on the surface, and (4) deposition of monolithic, adherent surface coatings by polymerization of monomeric species on the surface. Key features of these processes will be briefly discussed, with a rudimentary introduction to the chemistries involved, as well as examples. Focus is placed on capacitively coupled radio-frequency (rf) plasmas (see Figure 1 in the article by Lieberman et al. in this issue of MRS Bulletin) since they are most commonly used in polymer treatment.
14
Aido, Ahmed, Harald Wajant, Matej Buzgo et Aiva Simaite. « Development of Anti-TNFR Antibody-Conjugated Nanoparticles ». Proceedings 78, no 1 (1 décembre 2020) : 55. http://dx.doi.org/10.3390/iecp2020-08684.
Texte intégralRésumé :
Immunotherapy is considered as a new pillar of cancer treatment. However, the application of some promising immunotherapeutic antibodies, such as antibodies against certain immune-stimulatory receptors of the TNF receptor superfamily (TNFRs), including CD40, 41BB, CD27 and anti-fibroblast growth factor-inducible 14 (anti-Fn14), are limited due to their low bioactivity. It has been previously shown that the bioactivity of such anti-TNFR antibodies could be improved by crosslinking or attachment to the plasma membrane by interaction with Fcγ receptors (FcγR). Both result in the proximity of multiple antibody-bound TNFR molecules, which allow for the activation of proinflammatory signaling pathways. In this work, we have grafted antibodies on gold nanoparticles to simulate the “activating” effect of FcγR-bound, and thus plasma membrane-presented anti-TNFR antibodies. We have developed and optimized the method for the preparation of gold nanoparticles, their functionalization with poly-ethylene glycol (PEG) linkers, and grafting of antibodies on the surface. We showed here that antibodies, including the anti-Fn14 antibody PDL192, can be successfully attached to nanoparticles without affecting antigen binding. We hypothesize that conjugation of monoclonal anti-TNFR antibodies to the inorganic nanoparticles is a promising technique to boost the efficacy of these immunotherapeutic antibodies.
15
Haji, Aminoddin, Ahmad Mousavi Shoushtari et Majid Abdouss. « Plasma activation and acrylic acid grafting on polypropylene nonwoven surface for the removal of cationic dye from aqueous media ». Desalination and Water Treatment 53, no 13 (23 décembre 2013) : 3632–40. http://dx.doi.org/10.1080/19443994.2013.873350.
Texte intégral
16
Philippou, Helen, Antonella Adami, Simon Davidson, John Pepper, John Burman et David Lane. « Tissue Factor Is Rapidly Elevated in Plasma Collected from the Pericardial Cavity during Cardiopulmonary Bypass ». Thrombosis and Haemostasis 84, no 07 (2000) : 124–28. http://dx.doi.org/10.1055/s-0037-1613979.
Texte intégralRésumé :
SummaryThere is growing evidence that the tissue factor/factor VIIa pathway of coagulation is enhanced during cardiopulmonary bypass. Hitherto, available evidence has suggested that upregulated monocyte bound tissue factor is made available, either in the blood collected from the site of surgery or on circulating cells. However, cellular upregulation is slow, while generation of factor VIIa in blood collected from the pericardial cavity is rapid. We have therefore investigated the possibility of an alternative source of tissue factor, plasma (as opposed to cellular) tissue factor in blood samples taken from the central vein catheter (systemic circulation) and collected from the pericardial cavity during cardiopulmonary bypass. Six patients undergoing first time cardiopulmonary bypass grafting were studied. Tissue factor antigen was found to be rapidly elevated (by 15 min) in the pericardial plasma, ∼5-fold above systemic levels (p <0.004). Similar elevations were found in markers of coagulation activation, factor VIIa antigen (p = 0.066), prothrombin fragment F1+2 (p <0.003) and thrombin-antithrombin complex (p <0.03). To explore whether plasma tissue factor was (or had been) functionally active, factor VIIa was measured also with the soluble tissue factor functional assay after removal of heparin. Functional factor VIIa activity fell significantly in the systemic circulation, probably due to the heparin-induced increase (∼15-fold) in tissue factor pathway inhibitor (TFPI), but was elevated in pericardial blood compared with that taken from the central line catheter (p <0.006). These results demonstrate that both components of the activation complex for the extrinsic pathway of coagulation are rapidly generated in pericardial blood during bypass.
17
Yang, Y. T., et J. D. Liao. « Cell-surface interactions between rat Schwann cells and a biomimetic surface prepared by plasma activation and subsequent vapor grafting process ». Journal of Biomechanics 39 (janvier 2006) : S259. http://dx.doi.org/10.1016/s0021-9290(06)83986-2.
Texte intégral
18
Couturaud, Benoit, Andrea Molero Bondia, Clément Faye, Laurent Garrelly, André Mas et Jean Jacques Robin. « Grafting of poly-l-lysine dendrigrafts onto polypropylene surface using plasma activation for ATP immobilization – Nanomaterial for potential applications in biotechnology ». Journal of Colloid and Interface Science 408 (octobre 2013) : 242–51. http://dx.doi.org/10.1016/j.jcis.2013.06.065.
Texte intégral
19
Schatteman, Katinka, Filip Goossens, Elisabeth Moor, Simon Scharpé, Mats Strömqvist, Dirk Hendriks, Anders Hamsten et Angela Silveira. « Plasma Procarboxypeptidase U in Men with Symptomatic Coronary Artery Disease ». Thrombosis and Haemostasis 84, no 09 (2000) : 364–68. http://dx.doi.org/10.1055/s-0037-1614029.
Texte intégralRésumé :
SummaryProcarboxypeptidase U (proCPU) is the plasma precursor of carboxypeptidase U (CPU, carboxypeptidase R, plasma carboxypeptidase B or activated thrombin-activatable fibrinolysis inhibitor, TAFIa). CPU removes C-terminal lysine residues that act as plasminogen binding sites from partially degraded fibrin, thereby down-regulating plasminogen activation and fibrinolysis. The present study was carried out as a pilot study to examine whether the plasma proCPU concentration is related to the presence of coronary artery disease (CAD) and/or to levels of established risk indicators for CAD, in a case-control study of 110 men requiring coronary artery bypass grafting (CABG) because of stable angina pectoris. The preoperative plasma proCPU level in the CABG patients was significantly higher than in population-based controls (1029 ± 154 vs. 974 ± 140 U/L, p <0.05). In addition, in a subset of the patients (n = 31) the proCPU concentration, which was significantly lower on the third postoperative day (−17 ± 10%), had increased significantly on the sixth day (+14 ± 12%) after surgery, compared with the preoperative level. In both patients and controls, proCPU concentration was strongly and positively associated with factor VII amidolytic activity and protein C activity, suggesting a common mechanism modulating the plasma levels of these proteins. Otherwise, statistically significant correlations with proCPU were group-specific. In the patients, proCPU correlated significantly with plasma fibrinogen and protein S. In the controls, proCPU correlated significantly with concentrations of cholesterol in plasma, VLDL and LDL. In addition, proCPU correlated significantly with C-reactive protein and haptoglobin levels in the controls only, indicating that also inflammatory mechanisms are involved in the regulation of plasma proCPU. These results suggest that a mechanism exists by which fibrinolytic function is impaired in a manner that is likely to result in more stable fibrin deposits and increase the risk of precocious CAD as well as early occlusion of venous bypass grafts.
20
Alves, P., S. Pinto, Jean-Pierre Kaiser, Arie Bruinink, Hermínio C. de Sousa et M. H. Gil. « Surface grafting of a thermoplastic polyurethane with methacrylic acid by previous plasma surface activation and by ultraviolet irradiation to reduce cell adhesion ». Colloids and Surfaces B : Biointerfaces 82, no 2 (février 2011) : 371–77. http://dx.doi.org/10.1016/j.colsurfb.2010.09.021.
Texte intégral
21
Sablotzki, A., M. Dehne, I. Welters, T. Menges, N. Lehmann, G. Görlach, C. Osmer et G. Hempelmann. « Alterations of the cytokine network in patients undergoing cardiopulmonary bypass ». Perfusion 12, no 6 (décembre 1997) : 393–403. http://dx.doi.org/10.1177/026765919701200608.
Texte intégralRésumé :
Cardiovascular surgery using extracorporeal circulation causes a systemic inflammatory response which often results in severe organ dysfunction and increased postoperative mortality. Advances in knowledge about the interactions of cytokines involved in the response to cardiopulmonary bypass (CPB) may improve the outcome of patients undergoing cardiac surgery. The purpose of our study was to investigate the fluctuations in cytokine production, during and after CPB. In 24 patients undergoing elective coronary artery bypass grafting, plasma levels of interleukins IL-2, IL-6, IL-10 and IL-12, soluble IL-2-receptor (sIL-2R), and transforming growth factor-beta (TGF-β) were measured at eight time points before, during and after CPB, using a standardized enzyme-linked immunosorbant assay technique. There was a significant increase in plasma levels of IL-10, IL-6 and TGF-β after weaning off CPB. The IL-2 plasma levels decreased after the onset of CPB until 24 h postoperatively ( p < 0.05). Concentrations of sIL-2R decreased 20 min after the start of CPB until the end of the operation ( p < 0.05). In the postoperative course, sIL-2R levels increased, with peak values 48 h after the end of the surgical procedure. The IL-12 levels decreased after weaning off CPB ( p < 0.05) until 6 h postoperatively. The results of our study demonstrate an intraoperative-predominant immunosuppression, followed by an early postoperative immunological activation, combined with a distinct acute phase response.
22
Lu, He, Claudine Soria, Pierre-Louis Commin, Jeannette Soria, Armand Piwnica, Friedrich Schumann, Odile Regnier, Yves Legrand et Jacques Philippe Caen. « Hemostasis in Patients Undergoing Extracorporeal Circulation : The Effect of Aprotinin (Trasylol) ». Thrombosis and Haemostasis 66, no 06 (1991) : 633–37. http://dx.doi.org/10.1055/s-0038-1646477.
Texte intégralRésumé :
SummaryThe administration of aprotinin during extracorporeal circulation (ECC) reduces blood loss. To explore the mechanism of this effect, a placebo-controlled double-blind study was performed in 20 patients (10 were administered with a high dose of aprotinin, 10 with placebo) undergoing a primary, elective operation of coronary artery bypass grafting (CABG) with ECC. Biological tests were performed at 4 different time points during the operation.A marked reduction in the placebo group of ristocetin-induced platelet agglutination (binding of von Willebrand factor [vWF] to platelet glycoprotein [GP] Ib) was shown during ECC and at the end of surgery, but not in the aprotinin group. This abnormality is not related to the hydrolysis of vWF or GP Ib, since washed platelets were resuspended in pooled normal plasma which provided a constant amount of vWF in this test and since the plasma concentration of the fragment of GP Ib (glycocalicin) did not correlate with this abnormality.Despite a high concentration of heparin (5-7 IU/ml) in patient's plasma during bypass, activation of blood coagulation in both groups was evidenced by an increase in ATm (thrombin-modified antithrombin III) level. The level of ATm in the placebo group reached a maximum at the end of ECC during rewarming, while in the aprotinin group, ATm level at this time point was significantly lower than in the control group. In comparison to the placebo group, the generation of the fibrin degradation products (DDE complexes) was inhibited by aprotinin during ECC, but the level of DDE complexes in the aprotinin group was slightly elevated after ECC, although much less than in the placebo group. Other parameters measured did not show significant differences between the two groups.These results indicate that the hemostatic defect in patients during and after ECC may result, at least in part, from the impairment of GP Ib-dependent platelet adhesion. Therefore, the administration of aprotinin in ECC may improve hemostasis by abrogating this impairment, in addition to the protective effect of aprotinin on hemostatic plug. Activation of blood coagulation occurs during cardiopulmonary bypass despite heparin therapy and this activation seems to be partially inhibited by aprotinin administration.
23
Rivera, Carlos Eduardo, Hui Yan, Amanda Dee Fisher, Daniel Phillip Chupp, Raphael Simon, Hong Zan, Zhenming Xu et Paolo Casali. « Intrinsic B cell TLR-BCR linked coengagement induces mature and protective antibody responses in the absence of T cells ». Journal of Immunology 208, no 1_Supplement (1 mai 2022) : 53.07. http://dx.doi.org/10.4049/jimmunol.208.supp.53.07.
Texte intégralRésumé :
Abstract Maturation of the antibody response is critical for the generation of virus and bacteria neutralizing antibodies. It entails CSR and SHM together with plasma cell and memory B cell differentiation, and it is generally dependent on T cell help. Prompted by our finding that CSR and plasma cell differentiation can be induced in vitro by a TLR ligand together with BCR crosslinking, we hypothesized that TLR-BCR coengagement can induce a fully mature antibody response in vivo in the absence of T cells, and such coengagement must entail physical linkage of TLR and BCR ligands. To test this hypothesis, we vaccinated Tcrβ−/−Tcrδ−/− mice with NP-LPS or Salmonella Typhimurium flagellin (coengaging B-cell TLR4 with NP-specific BCR or TLR5 with flagellin-specific BCR). Vaccination of Tcrβ−/−Tcrδ−/− mice with NP-LPS or flagellin induced activation of the B cell NF-κB pathway to elicit NP or flagellin-specific class-switched IgG and IgA antibodies and plasma cells. It also induced formation of germinal center-like (GC) structures, B cell SHM, selective clonal expansion and intraclonal diversification, and generation of memory B cells. Similar antibody responses to NP and flagellin were reproduced in NSG/B mice (by grafting immunodeficient NSG mice with purified C57BL/6 mouse B cells), thereby showing that such responses could be generated in the absence of not only T cells but all other immune cells. Finally, LPS and flagellin induced class-switched and specific antibodies which neutralized E. coli and S. Typhimurium, respectively, and protected mice from lethal infection. Thus, TLR-BCR coengagement can induce a mature and protective antibody response, complete with CSR/SHM, plasma cell and memory B cell differentiation in the absence of T cells. Supported by NIH grants AI 079705, AI 105813/105813S1, AI138944, AI 167416 and Lupus Research Alliance grant LRA 641363 to Paolo Casali
24
Baksaas, Svein T., Hanne I. Flom-Halvorsen, Eivind Øvrum, Vibeke Videm, Tom Eirik Mollnes, Frank Brosstad et Jan L. Svennevig. « Leucocyte filtration during cardiopulmonary reperfusion in coronary artery bypass surgery ». Perfusion 14, no 2 (mars 1999) : 107–17. http://dx.doi.org/10.1177/026765919901400204.
Texte intégralRésumé :
Postoperative organ dysfunction after cardiac operations has been related to the damaging effects of cardiopulmonary bypass (CPB). These complications are considered to be mediated partly by complement activation and subsequent activation of leucocytes due to the contact between blood and the large nonendothelial surfaces in the bypass circuit. Removal of leucocytes by filtration during the reperfusion period may potentially reduce the postoperative morbidity after CPB. Forty patients undergoing elective, primary coronary artery bypass grafting were randomized to initial identical bypass circuits until the aortic crossclamp was released. Then, the ordinary arterial line filter was closed and either a leucocyte depletion filter ( n = 20), or a control filter ( n = 20) was incorporated in the circuits during the reperfusion period of CPB. Blood samples were drawn at fixed intervals and analysed for white blood cell and platelet counts, plasma concentration of myeloperoxidase, C3-complement activation products, the terminal complement complex, and interleukins (IL)-6 and -8. The numbers of circulating white blood cells in the leucocyte-depleted group decreased during the reperfusion period from 5.5 (4.8-6.8) to 5.3 (4.4-6.2) × 109/l, and increased in the control group from 6.5 (5.1-8.0) to 7.4 (5.7-9.0) × 109/l. Two hours postoperatively the total white blood cell count in the leucocyte-depleted group was 14.7 (12.1-17.2) × 109/l, and in the control group 17.6 (14.5-20.7) × 109/l. The differences between the groups were statistical significant ( p= 0.05). There were no statistically significant differences between the groups with regard to other test parameters or clinical data. We conclude that the use of leucocyte filters during the reperfusion period in elective coronary artery bypass surgery significantly reduced the number of circulating leucocytes, whereas no effects were seen for granulocyte activation measured as myeloperoxidase release, platelet counts, complement activation, or IL-6 and -8 release. The clinical benefit of leucocyte filters in routine or high risk patients remains to be demonstrated and is suggested to be dependent on both the efficacy and the biocompatibility of the filters.
25
Al-Ruzzeh, Sharif, Ginette Hoare, Nandor Marczin, George Asimakopoulos, Shane George, Kenneth Taylor et Mohamed Amrani. « Off-Pump Coronary Artery Bypass Surgery Is Associated with Reduced Neutrophil Activation as Measured by the Expression of CD11b : A Prospective Randomized Study ». Heart Surgery Forum 6, no 2 (2 février 2005) : 89. http://dx.doi.org/10.1532/hsf.1205.
Texte intégralRésumé :
<P>Background: Coronary artery bypass grafting (CABG) surgery is associated with systemic inflammation. Activation of neutrophils is a crucial step in inflammation and results in neutrophil sequestration within the tissues. One of the potential advantages of performing off-pump coronary artery bypass (OPCAB) surgery is the attenuation of the systemic inflammatory response. This prospective randomized study compares neutrophil activation in patients undergoing OPCAB versus those undergoing CABG with cardiopulmonary bypass (CPB). </P><P>Methods: Twenty patients undergoing primary isolated CABG were randomly divided prospectively into 2 groups: 1 group underwent CABG with CPB, and the other group underwent OPCAB. Central venous blood samples were obtained before skin incision and at 15 minutes, 60 minutes, 2 hours, 5 hours, and 24 hours following the initiation of CPB or application of the stabilization device. Differential white cell counts were measured with routine laboratory techniques. CD11b surface expression on neutrophils was measured by flow cytometry. Interleukin 8 levels in the plasma were measured by enzyme-linked immunosorbent assays. </P><P>Results: The 2 groups were matched with respect to preoperative and operative characteristics. White cell and neutrophil counts rose in both groups following the operation but were significantly higher in the OPCAB group at 5 hours (P < .001 and P = .002, respectively). Interleukin 8 concentrations were significantly higher in the CPB group at 5 hours following the initiation of CPB (P = .034). CD11b levels were significantly higher in the CPB group at 60 minutes (P = .002). Conclusion: This prospective randomized study demonstrates that the activation of circulating neutrophils as measured by CD11b expression is lower following OPCAB than in CPB. Although OPCAB is associated with significantly higher neutrophil counts, these neutrophils exhibit fewer activation markers. The lower postoperative neutrophil counts occurring in the CPB group may be explained by the activation and consequent sequestration of the neutrophils in the CPB circuit and tissues.</P>
26
Wojtkowska, Izabela, Tomasz A. Bonda, Jadwiga Wolszakiewicz, Jerzy Osak, Andrzej Tysarowski, Katarzyna Seliga, Janusz A. Siedlecki, Maria M. Winnicka, Ryszard Piotrowicz et Janina Stępińska. « Myocardial Expression of PPARγand Exercise Capacity in Patients after Coronary Artery Bypass Surgery ». PPAR Research 2017 (2017) : 1–7. http://dx.doi.org/10.1155/2017/1924907.
Texte intégralRésumé :
Activation of PPARs may be involved in the development of heart failure (HF). We evaluated the relationship between expression of PPARγin the myocardium during coronary artery bypass grafting (CABG) and exercise tolerance initially and during follow-up. 6-minute walking test was performed before CABG, after 1, 12, 24 months. Patients were divided into two groups (HF and non-HF) based on left ventricular ejection fraction and plasma proBNP level. After CABG, 67% of patients developed HF. The mean distance 1 month after CABG in HF was397±85 m versus420±93 m in non-HF. PPARγmRNA expression was similar in both HF and non-HF groups. 6MWT distance 1 month after CABG was inversely correlated with PPARγlevel only in HF group. Higher PPARγexpression was related to smaller LVEF change between 1 month and 1 year (R=0.18,p<0.05), especially in patients with HF. Higher initial levels of IL-6 in HF patients were correlated with longer distance in 6MWT one month after surgery and lower PPARγexpression. PPARγexpression is not related to LVEF before CABG and higher PPARγexpression in the myocardium of patients who are developing HF following CABG may have some protecting effect.
27
Chukwuemeka, A. O., M. RJ Turtle, U. H. Trivedi, G. E. Venn et D. J. Chambers. « A clinical evaluation of platelet function, haemolysis and oxygen transfer during cardiopulmonary bypass comparing the Quantum HF-6700 to the HF-5700 hollow fibre membrane oxygenator ». Perfusion 15, no 6 (décembre 2000) : 479–84. http://dx.doi.org/10.1177/026765910001500602.
Texte intégralRésumé :
The continued improvement of oxygenators is an important aspect of patient safety during cardiopulmonary bypass (CPB). The purpose of this study was to compare the Bard William Harvey HF-5700 oxygenator to the upgraded Bard Quantum HF-6700, which has recently been introduced into clinical practice. No clinical evaluation of this device has been published to date. The two oxygenators differ principally in that the Quantum has a smaller priming volume, achieved at the expense of a smaller membrane surface area which could result in sub-optimal gas exchange characteristics, increased haemolysis and increased platelet dysfunction during CPB. Twenty adult patients undergoing elective, first time coronary artery bypass grafting (CABG) were randomly assigned either to the HF-5700 ( n=10) or to the HF-6700 ( n=10) group. One patient underwent mitral valve repair in addition to CABG and was excluded from further study. There were no statistically significant differences in either preoperative or operative parameters between the two groups. Samples were obtained at the start of CPB, at 30 min, 60 min, at the end of CPB and at 1 h following termination of CPB. No significant differences between the two groups were found in oxygen transfer, haemolysis (plasma haptoglobin levels) or platelet function (a novel platelet activating factor (PAF)-induced platelet activation test) at any of the time points during CPB. It was concluded that the Quantum HF-6700 matches the HF-5700 for the parameters studied, whilst having the advantage of requiring a smaller priming volume.
28
Nezbedova, Eva, Frantisek Krcma, Zdenek Majer et Pavel Hutar. « Effect of particles size on mechanical properties of polypropylene particulate composites ». International Journal of Structural Integrity 7, no 5 (3 octobre 2016) : 690–99. http://dx.doi.org/10.1108/ijsi-09-2015-0030.
Texte intégralRésumé :
Purpose Polymeric particulate composites with thermoplastics, especially polypropylene (PP) matrix with mineral fillers, are of great practical importance due to their simple possibility of modifying mechanical properties and reducing the price/volume ratio of the resulting material. Both filler properties and interface properties have a great effect on the mechanical properties, primarily on stiffness and toughness, of the resulting composite material. Good final dispersion of the filler particles also plays a very important role. To reach the best adhesion and distribution of the particles, various procedures are carried out for activation of the particles. Therefore, the purpose of this paper is to investigate and discuss the effect of using plasma as a tool for treating commercially available CaCO3 nanoparticles in PP matrix. Design/methodology/approach The effect of the composite structure on its mechanical properties was studied from an experimental as well as a theoretical point of view. For an experimental study, four PP matrix were chosen. For use as filler, the commercially available precipitated surface-treated calcium carbonate was chosen. The composites were prepared with 5, 10, and 15 wt% of fillers. The sequence of expositions of plasma was chosen to verify the optimal treatment duration. The filler particles were characterized by several structure analytical methods. The composite mechanical properties were characterized by tensile, bending, impact, and creep tests. The deformation behavior of the three-phase composite with homogeneously distributed coated particles was numerically simulated on a microscopic scale. Findings The main conclusions of this work can be summarized as follows: with the use of plasma to the precipitated calcium carbonate, composites with well-dispersed particles can be prepared; the surface modification using plasma is done mainly by grafting –OH groups onto the particles’ surface; a synergetic effect of modifier enhancing the performance was observed; performance modifier increases the resistance against viscoelastic strain; and the size of the particles and their volume content generally lead to increase in the macro modulus of the composite. Originality/value Plasma, as a tool for treating the inorganic fillers, enables to destroy the agglomerates in composite, which is the basic way on how to optimally utilize the synergetic effect of composite with PP matrix.
29
De Somer, F., Y. Van Belleghem, F. Caes, K. François, J. Arnout, X. Bossuyt, Y. Taeymans et G. Van Nooten. « Phosphorylcholine coating offers natural platelet preservation during cardiopulmonary bypass ». Perfusion 17, no 1 (janvier 2002) : 39–44. http://dx.doi.org/10.1191/0267659102pf526oa.
Texte intégralRésumé :
Return of blood activated by tissue factor is the main culprit for triggering the coagulation cascade. When this activated blood is diverted from the cardiopulmonary bypass (CPB) circuit, it becomes possible to evaluate the effect of surface treatment on platelet and complement activation. Twenty adult patients undergoing elective coronary artery bypass grafting (CABG) were randomly assigned either to a control group ( n= 10) or to a group in which the CPB circuit was completely coated with phosphorylcholine ( n= 10). Plasma concentrations of platelet factor 4 (PF4), β-thromboglobulin (βTG), C3, C3d, C4, TCC, thrombin generation, haptoglobin and free haemoglobin, as well as blood loss, were measured. No significant differences between the two groups were found for haemolysis and thrombin generation. The mean total release of PF4 and βTG during CPB was 9338± 17303 IU/ml/CPB and 3790± 4104 IU/ml/CPB in the coated group versus 22192± 13931 IU/ml/CPB ( p= 0.011) and 8040± 3986 IU/ml/CPB ( p= 0.005) in the control group. Blood loss was 30% less in the coated group compared to the control group. Phosphorylcholine coating appears to have a favourable effect on blood platelets, which is most obvious after studying the changes during CPB. Clinically, this effect resulted in a 30% reduction in blood loss.
30
Aquino, Arthur, Napisat Abutalimova, Yi Ma, Imran Ismail-zade, Vadim Grebennik, Artem Rubinstein, Igor Kudryavtsev et al. « Differences in Plasma Extracellular Vesicles of Different Origin in On-Pump Versus Off-Pump Cardiac Surgery ». Current Issues in Molecular Biology 46, no 11 (17 novembre 2024) : 13058–77. http://dx.doi.org/10.3390/cimb46110779.
Texte intégralRésumé :
Coronary artery bypass grafting (CABG) using cardiopulmonary bypass (CPB) causes a systemic inflammatory response that can worsen patient outcomes. Off-pump surgery has been associated with a reduced inflammatory response. The precise mechanisms and the role of extracellular vesicles (EVs) in this context are not fully understood. This study aimed to investigate the early immune response, including main T- and B-lymphocyte subsets, cytokine profiles, and plasma EVs, in patients undergoing off-pump (n = 18) and on-pump (n = 18) CABG. Thirty-six patients undergoing isolated CABG were enrolled in this randomized control study. Pre- and 24 h postoperative blood samples were analyzed for immune cell populations, cytokine levels, and plasma EV phenotyping. Off-pump CABG triggered a milder immune response than on-pump surgery. On-pump surgery led to greater changes in circulating EVs, particularly platelet- (CD62P+), endothelial- (CD31+), and B-cell-derived (CD19+), as well as platelet- and erythrocyte-derived aggregates (CD41+CD235a+). Levels of platelet-derived EVs, expressing both constitutional and activation markers (CD41+CD62P+) decreased in both groups of patients 24 h after surgery. On-pump cardiac procedures led to an increase in T-regulatory cell-derived EVs (CD73+CD39+), suggesting a potential mechanism for immune suppression compared to off-pump surgery. There were numerous correlations between EV levels and cytokine profiles following on-pump surgery, hinting at a close relationship. Leucocyte-derived EVs exhibited positive correlations with each other and with GRO but showed negative correlations with endothelial-derived EVs (CD90+ and CD31+). Additionally, CD73+ EVs demonstrated positive correlations with platelet counts and with erythrocyte-derived CD235a+ EVs. EV changes were significantly greater after on-pump surgery, highlighting a more pronounced response to this type of surgery and emphasizing the role of EVs as regulators of post-surgical inflammation.
31
Funston, Wendy, Marie-Hélène Ruchaud-Sparagano, Jonathan Scott, Jason Powell, Faye A. H. Cooles, Lauren Shelmerdine, Cliona McDowell et al. « A human model of bilateral pulmonary vein sampling to assess the effects of one-lung ventilation on neutrophil function ». PLOS ONE 17, no 7 (26 juillet 2022) : e0271958. http://dx.doi.org/10.1371/journal.pone.0271958.
Texte intégralRésumé :
Background Neutrophil activation drives lung complications after cardiopulmonary bypass (CPB). Evidence suggests the healthy, ventilated lung may beneficially re-condition pro-inflammatory neutrophils. However, evidence in humans is lacking, due to a paucity of good models. CPB with simultaneous central venous and bilateral pulmonary vein sampling provides an opportunity to model effects of one-lung ventilation. The study’s primary objectives were to establish a model of intra-operative, bilateral pulmonary vein sampling and to determine whether neutrophil function differed after passing through inflated or deflated lungs. Methods Seventeen patients having “on pump” coronary artery bypass grafting (CABG) with one-lung ventilation (in two cohorts with tidal volume 2ml kg-1 and FiO2 0.21, or tidal volume 4 ml kg-1 and FiO2 0.5 respectively) were recruited. Cohort 1 consisted of 9 patients (7 male, median age 62.0 years) and Cohort 2 consisted of 8 male patients (median age 65.5 years). Recruitment was via prospective screening of scheduled elective and non-elective CABG procedures with cardiopulmonary bypass. Each patient had five blood samples taken—central venous blood pre-operatively; central venous blood pre-CPB; central venous blood post-CPB; pulmonary venous blood draining the ventilated lung post-CPB; and pulmonary venous blood draining the deflated lung post-CPB. Neutrophil phagocytosis and priming status were quantified. Plasma cytokines were measured. Results Phagocytosis and priming were not significantly different in neutrophils returning from the ventilated lung as compared to the non-ventilated lung. Plasma IL-6, IL-8 and IL-10 were significantly elevated by CPB. Conclusions The intra-operative, bilateral pulmonary vein sampling model provides unique opportunities to assess biological effects of interventions to one lung, with the other lung acting as an internal control. Single-lung ventilation during CPB had no significant effects on neutrophil function.
32
Kiaii, Bob, Stephanie Fox, Stuart A. Swinamer, Reiza Rayman, Jennifer Higgins, Andrew Cleland, Philip Fernandes et al. « The Early Inflammatory Response in a Mini–Cardiopulmonary Bypass System a Prospective Randomized Study ». Innovations : Technology and Techniques in Cardiothoracic and Vascular Surgery 7, no 1 (janvier 2012) : 23–32. http://dx.doi.org/10.1097/imi.0b013e3182552ade.
Texte intégralRésumé :
Objective The aim of this study was to compare the early systemic inflammatory response of the Resting Heart System (RHS; Medtronic, Minneapolis, MN USA), a miniaturized cardiopulmonary bypass (CPB) system, with two groups using a standard extracorporeal circulation system during on-pump coronary artery bypass grafting (CABG) surgery. Methods A total of 60 consecutive patients requiring CABG were prospectively randomized to undergo on-pump CABG using conventional CPB without cardiotomy suction (group A), conventional CPB with cardiotomy suction (group B), or the RHS (group C). Blood samples were collected at five time points: immediately before CPB, 30 minutes into CPB, immediately at the end of CPB, 30 minutes post-CPB, and 1 hour post-CPB. Inflammation was analyzed by changes in (a) levels of plasma proteins, including inflammatory cytokines (interleukin-6 [IL-6], IL-10, and tumor necrosis factor-α), chemokines (IL-8, monokine induced by interferon-γ, monocyte chemotactic protein-1, regulated on activation normal T cell expressed and secreted, and interferon-inducible protein-10), and acute phase proteins (C-reactive protein and complement protein 3); (b) biochemical variables (cardiac troponin I, hematocrit, and immunoglobulin G); and (c) cell numbers (leukocytes, neutrophils, and thrombocytes). Results The RHS showed more delayed secretion of the cytokines tumor necrosis factor-α and IL-10, chemokines monokine induced by interferon-γ (P < 0.001); IL-8, and interferon-inducible protein-10; and complement protein 3 than conventional CPB systems did. Median thrombocyte numbers were higher in the RHS group. Levels of cardiac troponin I, monocyte chemotactic protein-1, and IL-6 were lower in both the RHS and conventional CPB without suction than with suction. Levels of C-reactive protein and regulated on activation normal T cell expressed and secreted, plus leukocyte and neutrophil numbers, were similar in all groups. Conclusions The Medtronic RHS may induce less systemic inflammation than conventional CPB systems, particularly when cardiotomy suction was used, but it did not result in improved clinical benefit.
33
Özmen, Fulya, Serdar Korpayev, Pınar Akkaş Kavaklı et Cengiz Kavaklı. « Activation of inert polyethylene/polypropylene nonwoven fiber (NWF) by plasma-initiated grafting and amine functionalization of the grafts for Cu(II), Co(II), Cr(III), Cd(II) and Pb(II) removal ». Reactive and Functional Polymers 174 (mai 2022) : 105234. http://dx.doi.org/10.1016/j.reactfunctpolym.2022.105234.
Texte intégral
34
Manakhov, Anton M., Natalya A. Sitnikova, Alphiya R. Tsygankova, Alexander Yu Alekseev, Lyubov S. Adamenko, Elizaveta Permyakova, Victor S. Baidyshev et al. « Electrospun Biodegradable Nanofibers Coated Homogenously by Cu Magnetron Sputtering Exhibit Fast Ion Release. Computational and Experimental Study ». Membranes 11, no 12 (8 décembre 2021) : 965. http://dx.doi.org/10.3390/membranes11120965.
Texte intégralRésumé :
Copper-coated nanofibrous materials are desirable for catalysis, electrochemistry, sensing, and biomedical use. The preparation of copper or copper-coated nanofibers can be pretty challenging, requiring many chemical steps that we eliminated in our robust approach, where for the first time, Cu was deposited by magnetron sputtering onto temperature-sensitive polymer nanofibers. For the first time, the large-scale modeling of PCL films irradiation by molecular dynamics simulation was performed and allowed to predict the ions penetration depth and tune the deposition conditions. The Cu-coated polycaprolactone (PCL) nanofibers were thoroughly characterized and tested as antibacterial agents for various Gram-positive and Gram-negative bacteria. Fast release of Cu2+ ions (concentration up to 3.4 µg/mL) led to significant suppression of E. coli and S. aureus colonies but was insufficient against S. typhimurium and Ps. aeruginosa. The effect of Cu layer oxidation upon contact with liquid media was investigated by X-ray photoelectron spectroscopy revealing that, after two hours, 55% of Cu atoms are in form of CuO or Cu(OH)2. The Cu-coated nanofibers will be great candidates for wound dressings thanks to an interesting synergistic effect: on the one hand, the rapid release of copper ions kills bacteria, while on the other hand, it stimulates the regeneration with the activation of immune cells. Indeed, copper ions are necessary for the bacteriostatic action of cells of the immune system. The reactive CO2/C2H4 plasma polymers deposited onto PCL-Cu nanofibers can be applied to grafting of viable proteins, peptides, or drugs, and it further explores the versatility of developed nanofibers for biomedical applications use.
35
Boyle, Gethin, Agnieszka Kuffel, Kiran Parmar, Kirsty Gibson, Megan Smith, Aidan Grehan, Beverley J. Hunt et David J. Chambers. « A comparison of haemostatic biomarkers during low-risk patients undergoing cardiopulmonary bypass using either conventional centrifugal cell salvage or the HemoSep device ». Perfusion 34, no 1 (1 août 2018) : 76–83. http://dx.doi.org/10.1177/0267659118789051.
Texte intégralRésumé :
Background: Cardiac surgery using cardiopulmonary bypass (CPB) is associated with a coagulopathy due to haemodilution, thrombocytopenia and platelet dysfunction and the activation of coagulation and fibrinolysis, despite the use of large doses of unfractionated heparin. Conventional red cell salvage may exacerbate post-operative bleeding as plasma containing haemostatic factors is discarded. We hypothesized that a novel cell salvage device (HemoSep) may attenuate haemostatic changes associated with red cell salvage. We studied haemostatic markers following autologous transfusion from conventional cell salvage or the HemoSep device. Methods: This randomised, controlled trial compared haemostatic markers in patients undergoing coronary artery bypass grafting or aortic valve replacement who received autologous blood returned from cell salvage (control) or HemoSep (study). Blood samples were taken pre-operatively, end of CPB, post-transfusion of salvaged blood and 3 hours post-operatively and analysed for full blood count (FBC), prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, D-dimer and endogenous thrombin potential (ETP). Results: Fifty-four patients were recruited (n=28 control, n=26 study). Processed blood volume for transfusion was significantly (p<0.001) higher in the HemoSep group. In the HemoSep group, the PT was shorter (18.7±0.3 vs 19.9±0.3 sec; p<0.05) post-operatively and the aPTT was longer (48.6±3.8 vs 37.3±1.0 sec; p<0.01) following autologous transfusion. In the control group, D-dimer and ETP levels were higher (1903±424 vs.1088±151; p<0.05 and 739±46 vs. 394±60; p<0.001, respectively) following autologous transfusion. Conclusions: Although centrifuged cell salvage is known to adequately haemoconcentrate and remove unwanted substrates and bacteriological contamination, the process can exacerbate coagulopathy. The HemoSep device demonstrated some increase in haemostatic markers when used in low-risk cardiac surgery patients.
36
Qureshi, Shabir H., Likui Yang, Peyman Dinarvand et Alireza R. Rezaie. « Engineering D-helix of antithrombin in alpha-1-proteinase inhibitor confers antiinflammatory properties on the chimeric serpin ». Thrombosis and Haemostasis 112, no 07 (2014) : 164–75. http://dx.doi.org/10.1160/th13-12-1029.
Texte intégralRésumé :
SummaryAntithrombin (AT) is a heparin-binding serpin in plasma which regulates the proteolytic activity of procoagulant proteases of the clotting cascade. In addition to being an anticoagulant, AT also exhibits antiinflammatory activities when it binds to cell surface heparan sulfate proteoglycans (HSPGs) on the endothelium via its basic residues of D-helix to elicit intracellular signalling responses. By contrast to AT, α1-proteinase inhibitor (α1-PI) is a non-heparin-binding serpin that exhibits very slow reactivity with coagulation proteases and possesses no HSPG-dependent antiinflammatory properties. To determine whether the antiinflammatory signaling specificity of AT can be transferred to α1-PI, we replaced the D-helix of human α1-PI with the corresponding sequence of human AT and expressed the chimeric serpin α1-PI/D-helix) in a bacterial expression system. High molecular weight heparin bound to α1-PI/D-helix and accelerated the inhibition of thrombin by the serpin mutant by a template mechanism reminiscent of the cofactor effect of heparin on inhibition of thrombin by AT. Like AT, α1-PI/D-helix exhibited antiinflammatory properties in both cellular and animal models. Thus, α1-PI/D-helix inhibited the barrier-disruptive effect of proinflammatory cytokines and inhibited the activation of nuclear factor-kB transcription factor in lipopolysaccharide-stimulated endothelial cells by a concentration-dependent manner. Furthermore, the chimeric serpin reduced lipopolysaccharide-mediated lethality, elicited a vascular protective effect and inhibited infiltration of activated leukocytes to the peritoneal cavity of mice in an HMGB1-mediated inflammatory model. These results suggest that grafting the D-helix of AT to α1-PI confers antiinflammatory properties on the serpin and that the chimeric serpin may have therapeutic utility for treating inflammatory disorders.
37
Driessen, JJ, H. Dhaese, G. Fransen, P. Verrolst, L. Rondelez, L. Gevaert, M. van Becelaere et E. Scheistraete. « Pulsatile compared with nonpulsatile perfusion using a centrifugal pump for cardiopulmonary bypass during coronary artery bypass grafting. Effects on systemic haemodynamics, oxygenation, and inflammatory response parameters ». Perfusion 10, no 1 (janvier 1995) : 3–12. http://dx.doi.org/10.1177/026765919501000102.
Texte intégralRésumé :
The present study investigated the influence of pulsatile or nonpulsatile flow delivery with a centrifugal pump for cardiopulmonary bypass (CPB) during coronary artery bypass grafting (CABG) in two randomized groups of 19 patients each. All patients received a standard anaesthetic and surgical protocol. Pulsatile perfusion during CPB was created by accelerating the baseline pump speed of the Sarns centrifugal pump at a rate of 50 cycles per minute. Measurements included perioperative systemic haemodynamics and oxygen exchange, total haemolytic complement (CH 50), polymorphonuclear (neutrophil) granulocyte (PMN) count and plasma granulocyte elastase bound to α1-proteinase inhibitor (E-α 1-PI). Laboratory measurements were corrected for haemodilution. During and after CPB there were only a few significant differences between the groups in systemic haemodynamics and oxygenation, i.e. a lower mean arterial blood pressure after the end of CPB in the nonpulsatile group (65 mmHg, SD = 11 vs 76 mmHg, SD = 11) and a lower SvO2 during rewarming on CPB in the nonpulsatile group (62%, SD = 8 vs 67%, SD = 8). The decrease in percentage of PMNs in the total white blood cell count during CPB was greater in the nonpulsatile group than in the pulsatile group (from 61 to 46% vs 63 to 53% of prebypass value). The steep increase of PMN count at the end of CPB and postoperatively was comparable in both groups. The maximal decrease of CH50 levels, occurring after surgery, was significantly higher in the nonpulsatile group (70%, SD = 15 vs 79%, SD = 16, of baseline value), suggesting a greater complement activation. E-α1-PI levels increased significantly in both groups during and after CPB with higher peak levels, obtained at one hour after admission to an intensive care unit, in the nonpulsatile group (316 μg/l, SD = 102) than in the pulsatile group (247 μg/l, SD = 106). There was a partly inverse correlation between the peak postoperative elastase levels and the PaO2/FiO2 ratios at the first postoperative morning. This ratio was significantly lower in the nonpulsatile group (211, SD = 56) than in the pulsatile group (247, SD = 62). Postoperative respiratory tract infection was more frequent in the nonpulsatile group (n = 9) than in the pulsatile group (n = 2). Adding a pulsatile component to centrifugal blood pumping during CPB may have benefits with regard to the possibly detrimental whole body inflammatory response to CPB. Further studies are warranted to investigate whether these differences will affect clinical outcome.
38
Jacobs, S., F. De Somer, G. Vandenplas, Y. Van Belleghem, Y. Taeymans et G. Van Nooten. « Active or passive bio-coating : does it matters in extracorporeal circulation ? » Perfusion 26, no 6 (30 juin 2011) : 496–502. http://dx.doi.org/10.1177/0267659111415146.
Texte intégralRésumé :
Background: Two types of surface coating for cardiopulmonary bypass (CPB) are used: bioactive (heparin, nitric oxide) and biopassive (albumin, polyethyleneoxide (PEO), phosphorylcholine). When haemocompatible coatings are combined with the separation of pleuro-pericardial aspiration, attenuation of both the coagulation and complement cascades, as well as better platelet preservation, has been demonstrated. This study wants to investigate if the combination of a bioactive with a biopassive coating (unfractionated heparin embedded in a phosphorylcholine matrix) combines the beneficial effects of both approaches. Materials and methods: Thirty patients undergoing elective CABG were prospectively randomized into two groups of 15 patients. The sole exclusion criterion was an ejection fraction of less than 40%. In the control group (PC), the whole CPB circuit was coated with phosphorylcholine (PC). In the study group (XPC), unfractionated heparin was embedded in the PC matrix of the oxygenator and arterial line filter. Results: No differences were found for haemolytic index, thrombin-anti-thrombin complex (TAT), IL-6, IL-10 and blood loss. PF4 plasma concentration increased from 27.6±22.0 IU/mL to 165.7±43.9 IU/mL (p<0.001) at 15 minutes of CPB in the PC and from 16.0±9.7 IU/mL to 150.9 ± 61.3 IU/mL (p<0.001) in the XPC group. Terminal complement complex (TCC) increased over time in both groups until the end of CPB (Figure 2A). Within each group, TCC generation was statistically significantly higher after the release of the aortic cross-clamp (p<0.001) and at the end of CPB (p<0.001). Total TCC generation was statistically significantly higher in the XPC group compared to the PC group (p=0.026). The difference was statistically significant after the release of the aortic cross-clamp (p=0.005) and at the end of CPB (p=0.001). Conclusions: Based on our results, there is no additional benefit in combining phosphorylcholine with unfractionated heparin in elective patients undergoing coronary artery bypass grafting (CABG). Massive haemodilution leads to enhanced complement activation.
39
Thiant, Stephanie, Zaiba Shamim, Lars Peter, Valérie Coiteux, Jean Paul Dessaint, Myriam Labalette, Klaus Muller et Ibrahim Yakoub-Agha. « Impact of Donor IL-7Rα Polymorphism On Recipient Plasma IL-7 levels and Acute Gvhd Following Allogeneic Stem Cell Transplantation. » Blood 116, no 21 (19 novembre 2010) : 1464. http://dx.doi.org/10.1182/blood.v116.21.1464.1464.
Texte intégralRésumé :
Abstract Abstract 1464 IL-7 is one of essential driving forces for homeostatic peripheral expansion of T lymphocytes that are responsible, not only for GVL effects but also for acute GVHD, a major post-transplant complication. High plasma levels of IL-7 in the early phase post-transplant, has been associated with high incidence of severe acute GVHD regardless the intensity of conditioning regimen. Inter-individual variations have also been reported. Here we aimed to identify factors that could have an impact on IL-7 level and, therefore, on acute GVHD. This prompted us to prospectively investigate plasma levels of IL-7, T-cell subsets recovery, T cells’ IL-7Rα chain expression, and IL-7Rα chain polymorphism in 100 pts who underwent fully HLA-matched allogeneic stem cell transplantation in our unit. Pts received either myeloablative (n= 60) or nonmyeloablative (n=40). Forty donors were unrelated. Source of stem cells, was bone marrow in 71 pts and PBCS in 29. Sex ratio (M/F) was (66/34) and median age at transplant was of 49 years. Plasma IL-7 level was determined by ELISA at enrolment, on day 0 before grafting, every three days during the first month, and then on days 60 and 90. CD3+, CD4+, CD8+ T-cells and NK cells counts at day 30, 60 and 90 post-graft were obtained by flow-cytometry-based technique. Expression of IL-7Rα (% and MFI) was evaluated on each subset of naïve and memory T-cells, categorized according to their expression of CD45RA and CCR7 markers. The detection of IL-7Ra single nucleotide polymorphism (SNPs) by sequence specific PCR (SSP), in donors, was carried out as described by Shamim et al, (BMT 2006). IL-7 receptor consisted of γc-chain and specific α-chain. A range of IL7R α-chain SNPs was reported (+510 C/T, +1237 A/G, +2087 T/C which all resulted in amino-acid substitution). At the time of analysis, 40 (40%) recipients had developed grade 2–4 acute GVHD (aGVHD) with a median time of 33 days post transplant. As expected, IL-7 levels peaked around the second week at median of 11.5 pg/mL (0.4-30.2) after transplant. Kinetic courses of plasma IL-7 levels, evolved inversely to lymphocyte counts up to d+30 (p<.001). The cumulative incidence of aGVHD was higher if by day+18 pts had IL-7 levels above the median concentration (p= .046). A higher level of IL-7 at day+18 was confirmed as a predictive factor of subsequent risk of aGVHD (HR= 1,079; 95% CI: 1.022 – 1.139; p= .006). By calculating the area under the curve of IL-7 between d-15 and d+30, we observe that a high exposure to IL-7 during the first month is correlated with the risk of aGVHD (p=.002). IL-7 plasma levels were inversely correlated with IL-7Rα expression only on central/effector memory CD4+ and central/effector memory CD8+, and terminally differentiated CD8+ T-cells (p =.006, .013, .044, .001 and .028, respectively). Of note, at d+30, pts had 85% (34-99) and 86% (23-99) of CD4+ and CD8+ memory T cells, respectively. Contrary to +1237 A/G and +2087 T/C, donor's +510 CC or CT was the only polymorphism to be associated with higher level of plasma IL-7 in recipients during the first month post-transplant in particular at d+18, predictive date for aGVHD (p = .026). In multivariate analysis, pts who received graft from donor with +510CC or CT experienced more often grade 2–4 aGVHD than those with +510 TT (P = .049). Collectively, this study confirms the role of IL-7 in grade 2–4 aGVHD. Indeed, the high level of IL-7 that down regulates IL-7Rα, could suggest activation and consumption of IL-7 by alloreactive T cells, including those involved in aGVHD development. By difference in affinity and cytokine consumption, the polymorphism +510 of donor t-cell IL-7R α-chain might explain, in part, the wide variation of IL-7 level among pts. Disclosures: No relevant conflicts of interest to declare.
40
Wen, Yi Fang, Tai Yong Wang et Hong Wei Wang. « Design of Plasma Discharge Structure for Surface Treatment of PP Film ». Key Engineering Materials 693 (mai 2016) : 77–83. http://dx.doi.org/10.4028/www.scientific.net/kem.693.77.
Texte intégralRésumé :
Low temperature plasma, compared to liquid phase treatment, can effectively overcome the environment pollution, high energy loss and high cost as its high activity. The low temperature plasma, which is not only fairly friendly to the environment but also of less resource consumption, also can realize the cleaning, activating and grafting treatment for materials surface. Based on the numerical model of CRFHCP (Capacitive Radio Frequency Hollow Cathode Plasma) hollow cathode plasma discharge, the key point to affect plasma discharge was analyzed and the morphology of PP film before and after hollow cathode plasma discharge was analyzed. The results showed that the structure of plasma hollow cathode discharge can effectively improved the chemical behaviors of PP film.
41
Peter, Karlheinz, Johannes Ruef, Wolfgang Kübler, Christoph Bode et Thomas K. Nordt. « Plasminogen Activator Inhibitor Type-1 (PAI-1) and its Role in Cardiovascular Disease ». Thrombosis and Haemostasis 82, S 01 (1999) : 14–18. http://dx.doi.org/10.1055/s-0037-1615546.
Texte intégralRésumé :
SummaryCardiovascular disease is responsible for approximately 50% of total mortality in Europe, the USA and Japan (1). Established risk factors including smoking, hypercholesterolemia, and hypertension explain about half of the incidence of cardiovascular disease only (2). Reduced endogenous fibrinolytic activity secondary to increased plasma activity of plasminogen activator inhibitor type-1 (PAI-1) is now considered as a new cardiovascular risk factor. In this review, evidence is gathered for the notion that PAI-1 constitutes a predictor of cardiovascular disease and also contributes to the development of cardiovascular disease as a pathogenetic factor. The review will focus on experimental studies modulating PAI-1 activity and clinical studies addressing coronary heart disease, myocardial infarction, restenosis after coronary angioplasty, and graft occlusion after coronary artery bypass grafting.
42
Lieder, Helmut Raphael, Pia Tüller, Felix Braczko, Afsaneh Zandi, Markus Kamler, Matthias Thielmann, Gerd Heusch et Petra Kleinbongard. « Bioassays of Humoral Cardioprotective Factors Released by Remote Ischemic Conditioning in Patients Undergoing Coronary Artery Bypass Surgery ». Journal of Cardiovascular Pharmacology and Therapeutics 27 (1 janvier 2022) : 107424842210972. http://dx.doi.org/10.1177/10742484221097273.
Texte intégralRésumé :
Remote ischemic conditioning (RIC) induces the release of circulating cardioprotective factors and attenuates myocardial ischemia/reperfusion injury. Evidence for such humoral cardioprotective factor(s) is derived from transfer with plasma (derivatives) from one individual undergoing RIC to another individual’s heart, even across species. With transfer into an isolated perfused heart, only a single plasma (derivative) sample can be studied with infarct size as endpoint, and therefore the comparison of samples before and after RIC or between RIC and placebo is hampered by the inter-individual variation of infarct sizes in isolated perfused hearts. We therefore developed a preparation of cardiomyocytes from a single mouse heart, where aliquots of the same heart can undergo hypoxia/reoxygenation (H/R) with exposure to buffer, RIC, or placebo samples without or with pharmacological blockade. To validate this approach, we used plasma dialysates taken before and after RIC from patients undergoing coronary bypass grafting who had experienced protection by RIC (troponin release ↓ by 28% vs placebo). The cardiomyocyte bioassay had little variation after H/R with buffer (mean ± standard deviation; 7% ± 2% viable cells) and demonstrated preserved viability after RIC (15% ± 5% vs 6% ± 3% before). For comparison, infarct size in isolated mouse hearts after global ischemia and reperfusion was 22% ± 14% of left ventricular mass after versus 42% ± 14% before RIC. Stattic, an inhibitor of signal transducer and activator of transcription (STAT)3 protein, abrogated protection in the cardiomyocytes. We have thus established a cardiomyocyte bioassay to analyze RIC’s protection which minimizes inter-individual variation and the use of animals.
43
Lalić, K., P. B. Djordjević, N. M. Lalić, D. Bošković, M. Zamaklar, A. Jotić, M. Ilić, N. Rajković et Lj Lukić. « 3.P.323 Graft stenosis after coronary artery bypass grafting in patients with non-insulin-dependent diabetes : An association with higher plasma insulin and plasminogen activator inhibitor 1 levels ». Atherosclerosis 134, no 1-2 (octobre 1997) : 266. http://dx.doi.org/10.1016/s0021-9150(97)89400-2.
Texte intégral
44
Sethi, Vipula, Chetna Verma, Samrat Mukhopadhyay, Amlan Gupta et Bhuvanesh Gupta. « Functional Surfaces by Plasma Grafting of Itaconic Acid onto Polypropylene Mesh : Synthesis & ; Structural Investigations ». Polymer International, 14 décembre 2023. http://dx.doi.org/10.1002/pi.6603.
Texte intégralRésumé :
AbstractPolypropylene (PP) is an unflinching element of biomaterials for human healthcare, leading to enormous probabilities for their functional development within a broad range of biocompatible and bioreceptive materials. Plasma grafting of itaconic acid was carried on a PP surface by oxygen plasma activation. The variation of grafting parameters, such as monomer concentration, reaction temperature and reaction time as a function of the degree of grafting was investigated. The graft distribution and surface homogeneity of the PP surfaces were evaluated using confocal microscopy, field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). These surface characterizations led to the intensity of information about the impact of grafts on the material surface.This article is protected by copyright. All rights reserved.
45
Gleissner, Carolin, Thomas Bechtold et Tung Pham. « Enhancing the Wettability of Fibre Surface : A Comparative Experimental Study of Different Surface Activation Principles on Single Polyamide Fibre ». Fibers and Polymers, 8 novembre 2023. http://dx.doi.org/10.1007/s12221-023-00402-6.
Texte intégralRésumé :
AbstractIn this study, we have compared three different principles of surface activation with regard to their effects on the properties of single polyamide fibres. The techniques used include the complexation-mediated surface treatment using CaCl2/EtOH/H2O solution (CEW), the atmospheric pressure plasma treatment with air (APPA) and grafting polymerisation process with 2- hydroxyethyl methacrylate (HEMA). The CEW modification, the plasma treatment and the grafting process induced a decrease in advancing contact angle and thus led to an improved wettability of the polyamide fibre. While for the CEW treatment, the decrease was solely due to a change in topography such as increased surface roughness leading to increased capillary effect, for the APPA and grafting technique the decrease was attributed to a combination of increased surface roughness and increased amount of oxygen or nitrogen-containing groups as detected by XPS. In addition, the fibre fineness decreased in the case of CEW treatment due to a dissolution of polyamide segments during the modification, while it increased in the grafting process due to an additional grafted layer. However, an increase in wetted length was observed for most samples, which was attributed to the increased waviness of the fibres. All treatments induced a decrease in fibre tensile strength that decreased with increasing treatment intensity.
46
Jin, Qiaoru, Xue Zhang, Fuzhi Li et Xuan Zhao. « Hydrophobic modification of a PVDF hollow fiber membrane by plasma activation and silane grafting for membrane distillation ». Water Science & ; Technology, 29 mai 2023. http://dx.doi.org/10.2166/wst.2023.166.
Texte intégralRésumé :
Abstract Polyvinylidene fluoride (PVDF) hollow fibers were hydrophobically modified using a simple and scalable method of plasma activation and silane grafting. The effects of plasma gas, applied voltage, activation time, silane type, and concentration were investigated according to the membrane hydrophobicity and direct contact membrane distillation (DCMD) performance. Two kinds of silane were used, including methyl trichloroalkyl silane (MTCS) and 1H,1H,2H,2H-perfluorooctane trichlorosilane silanes (PTCS). The membranes were characterized by techniques such as FTIR, SEM, XPS, and contact angle. The contact angle of the pristine membrane was 88°, which increased to 112°–116° after modification. Meanwhile, the pore size and porosity decreased. In DCMD, the maximum rejection reached 99.95% by the MTCS-grafted membrane, while the flux decreased by 35 and 65% for the MTCS- and PTCS-grafted membranes, respectively. Treating humic acid-contained solution, the modified membrane showed steadier water flux and higher salt rejection than the pristine membrane, and 100% flux recovery was achieved by simple water flushing. This two-step method of plasma activation and silane grafting is very simple and effective to improve the hydrophobicity and DCMD performance of PVDF hollow fibers. However, further study on improving the water flux should be carried out.
47
Gleissner, Carolin, Christian Biermaier, Thomas Bechtold et Tung Pham. « Altering the percolation threshold of PA66‐copper hybrid in an electroless copper deposition process by surface activation of the polymer ». Polymer Composites, 2 juillet 2024. http://dx.doi.org/10.1002/pc.28754.
Texte intégralRésumé :
AbstractIn this study, the impact of three different principles of surface activation techniques for polyamide fibers on the formation of conductive percolation during the subsequent electroless copper deposition process was investigated. The techniques used are (1) polyamide complexation using a solution mixture of calcium chloride, ethanol and water, (2) atmospheric plasma surface treatment and (3) grafting of 2‐hydroxyethylmethacrylate by radical induced polymerization. As a result, the percolation threshold was shifted to lower copper contents. The copper content required to form conductive structures was reduced ranged between 59% and 89%, depending on the activation techniques. Furthermore, the deposition time was reduced by 37%–57%, resulting in a faster build‐up of the percolation on the fabric. Changes in wetting behavior and substrate surface topography were identified to be the main reasons for these observations. While all applied surface activation techniques led to higher copper contents compared to unmodified reference, the atmospheric plasma modification led to the highest copper contents during the deposition process and a more uniform appearance of the metallised layer.Highlights Three different fiber surface activation methods are evaluated. Fiber surface activation increases wetting and polymer‐metal adhesion. Activated polymer surface leads to faster copper deposition and percolation. Atmospheric plasma modification is the most efficient technique.
48
Zhang, Peng, et Ru Li. « Preparation and performance of acrylic acid grafted PES ultrafiltration membrane via plasma surface activation ». High Performance Polymers, 16 juin 2022, 095400832211043. http://dx.doi.org/10.1177/09540083221104391.
Texte intégralRésumé :
A modified PES ultrafiltration membrane with excellent separation and antifouling properties was obtained after modification by remote Ar–NH3 plasma-induced acrylic acid (AA) grafting. Hydrophilic properties were characterised using water contact angle measurements. The morphology was analysed using SEM and BET measurements. Changes in the surface functional groups were determined using XPS and ATR-FTIR. The separation and antifouling properties were evaluated through a bovine serum albumin (BSA) separation experiment. The results revealed that the surface structure of the modified membrane was not destroyed, that amino groups were introduced on the surface of the PES membrane, and that AA was successfully grafted. The water contact angle decreased from 67° in the original membrane to 5 ± 0.63° in the modified membrane. The water flux increased from 30 to 93.6 L/(m2·h). The rejection rate of BSA increased from 61.5 to 93.8%, and the flux recovery rate increased from 60.0 to 92.3%.
49
Bol, Martine E., J. B. Huckriede, K. G. H. van de Pas, T. Delhaas, R. Lorusso, G. A. F. Nicolaes, J. E. M. Sels et M. C. G. van de Poll. « Multimodal measurement of glycocalyx degradation during coronary artery bypass grafting ». Frontiers in Medicine 9 (29 novembre 2022). http://dx.doi.org/10.3389/fmed.2022.1045728.
Texte intégralRésumé :
BackgroundGlycocalyx shedding and subsequent endothelial dysfunction occur in many conditions, such as in sepsis, in critical illness, and during major surgery such as in coronary artery bypass grafting (CABG) where it has been shown to associate with organ dysfunction. Hitherto, there is no consensus about the golden standard in measuring glycocalyx properties in humans. The objective of this study was to compare different indices of glycocalyx shedding and dysfunction. To this end, we studied patients undergoing elective CABG surgery, which is a known cause of glycocalyx shedding.Materials and methodsSublingual glycocalyx thickness was measured in 23 patients by: 1) determining the perfused boundary region (PBR)—an inverse measure of glycocalyx thickness—by means of sidestream dark field imaging technique. This is stated double, 2) measuring plasma levels of the glycocalyx shedding products syndecan-1, hyaluronan, and heparan sulfate and 3) measuring plasma markers of impaired glycocalyx function and endothelial activation (Ang-2, Tie-2, E-selectin, and thrombomodulin). Measurements were performed directly after induction, directly after onset of cardiopulmonary bypass (CPB), and directly after cessation of CPB. We assessed changes over time as well as correlations between the various markers.ResultsThe PBR increased from 1.81 ± 0.21 μm after induction of anesthesia to 2.27 ± 0.25 μm (p < 0.0001) directly after CPB was initiated and did not change further during CPB. A similar pattern was seen for syndecan-1, hyaluronan, heparan sulfate, Ang-2, Tie-2, and thrombomodulin. E-selectin levels also increased between induction and the start of CPB and increased further during CPB. The PBR correlated moderately with heparan sulfate, E-selectin, and thrombomodulin and weakly with Syndecan-1, hyaluronan, and Tie-2. Shedding markers syndecan-1 and hyaluronan correlated with all functional markers. Shedding marker heparan sulfate only correlated with Tie-2, thrombomodulin, and E-selectin. Thrombomodulin correlated with all shedding markers.ConclusionOur results show that glycocalyx thinning, illustrated by increased sublingual PBR and increased levels of shedding markers, is paralleled with impaired glycocalyx function and increased endothelial activation in CABG surgery with CPB. As correlations between different markers were limited, no single marker could be identified to represent the glycocalyx in its full complexity.
50
Moore, Eli, Alexander J. Robson, Amy R. Crisp, Michaelia P. Cockshell, Anouck L. S. Burzava, Raja Ganesan, Nirmal Robinson et al. « Study of the Structure of Hyperbranched Polyglycerol Coatings and their Anti‐Biofouling and Anti‐Thrombotic Applications ». Advanced Healthcare Materials, 24 juin 2024. http://dx.doi.org/10.1002/adhm.202401545.
Texte intégralRésumé :
AbstractWhilst blood‐contacting materials are widely deployed in medicine in vascular stents, catheters and cannulas, devices fail in‐situ because of thrombosis and restenosis. Furthermore, microbial attachment and biofilm formation is not an uncommon problem for medical devices. Even incremental improvements in hemocompatible materials could provide significant benefits for patients in terms of safety and patency as well as substantial cost savings.Herein, we describe a novel but simple strategy for coating a range of medical materials, that can be applied to objects of complex geometry, involving plasma‐grafting of an ultra‐thin hyperbranched polyglycerol coating (HPG). Plasma activation creates highly reactive surface oxygen moieties that readily react with glycidol. Irrespective of the substrate, coatings are uniform and pinhole free, comprising O‐C‐O repeats, with HPG chains packing in a fashion that holds reversibly binding proteins at the coating surface.In vitro assays with planar test samples show that HPG prevents platelet adhesion and activation, as well as reducing (>3log) bacterial attachment and preventing biofilm formation. Ex vivo and preclinical studies show that HPG‐coated nitinol stents do not elicit thrombosis or restenosis, nor complement or neutrophil activation. Subcutaneous implantation of HPG coated disks under the skin of mice showed no evidence of toxicity nor inflammation.This article is protected by copyright. All rights reserved