Meniscal allograft transplantation. Part 1: systematic review of graft biology, graft shrinkage, graft extrusion, graft sizing, and graft fixation.

Science.gov (United States)

Samitier, Gonzalo; Alentorn-Geli, Eduard; Taylor, Dean C; Rill, Brian; Lock, Terrence; Moutzouros, Vasilius; Kolowich, Patricia

2015-01-01

To provide a systematic review of the literature regarding five topics in meniscal allograft transplantation: graft biology, shrinkage, extrusion, sizing, and fixation. A systematic literature search was conducted using the PubMed (MEDLINE), ScienceDirect, and EBSCO-CINAHL databases. Articles were classified only in one topic, but information contained could be reported into other topics. Information was classified according to type of study (animal, in vitro human, and in vivo human) and level of evidence (for in vivo human studies). Sixty-two studies were finally included: 30 biology, 3 graft shrinkage, 11 graft extrusion, 17 graft size, and 6 graft fixation (some studies were categorized in more than one topic). These studies corresponded to 22 animal studies, 22 in vitro human studies, and 23 in vivo human studies (7 level II, 10 level III, and 6 level IV). The principal conclusions were as follows: (a) Donor cells decrease after MAT and grafts are repopulated with host cells form synovium; (b) graft preservation alters collagen network (deep freezing) and causes cell apoptosis with loss of viable cells (cryopreservation); (c) graft shrinkage occurs mainly in lyophilized and gamma-irradiated grafts (less with cryopreservation); (d) graft extrusion is common but has no clinical/functional implications; (e) overall, MRI is not superior to plain radiograph for graft sizing; (f) graft width size matching is more important than length size matching; (g) height appears to be the most important factor influencing meniscal size; (h) bone fixation better restores contact mechanics than suture fixation, but there are no differences for pullout strength or functional results; and (i) suture fixation has more risk of graft extrusion compared to bone fixation. Systematic review of level II-IV studies, Level IV.

Chloroanthraquinone as a grafted probe molecule to investigate grafting yield on carbon powder

International Nuclear Information System (INIS)

Le Comte, Annaïg; Brousse, Thierry; Bélanger, Daniel

2016-01-01

Spontaneous grafting of chloroanthraquinone (ClAQ) groups on Black Pearls carbon by reduction of the corresponding in-situ generated diazonium cations was successfully achieved. The presence of an halogen atom on the quinone molecule allowed the use of different spectroscopic characterization techniques to determine the accurate quinone content of the modified carbon. Electrochemical characterization highlighted that the presence of chlorine atom on the grafted molecule did not affect the electrochemical response or the grafting reaction efficiency. The amount of ClAQ molecules at the carbon surface after grafting was determined by cyclic voltammetry, together with thermogravimetric analysis coupled mass spectroscopy, X-ray photoelectron spectroscopy and elemental analysis. The ClAQ mass loadings estimated from the four techniques are in very good agreement and confirm that the grafted moieties are all electrochemically active and accessible. Finally, the grafting of quinone-type molecule using the reduction of diazonium cations does not affect the electroactivity of the grafted groups and cyclic voltammetry can be considered as a reliable technique to evaluate the mass loading of grafted quinone groups on porous carbon. Thus ClAQ can be used as a grafted probe molecule to investigate grafting yield on carbon powder, and this approach can be extended to functionalized electrodes used in an increasing number of electrochemical energy storage devices.

Antibacterial activity of silver nanoparticles stabilized on tannin-grafted collagen fiber

Energy Technology Data Exchange (ETDEWEB)

He Li [National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065 (China); Gao Siying; Wu Hao [Department of Biomass Chemistry and Engineering, Sichuan University, Chengdu 610065 (China); Liao Xuepin, E-mail: xpliao@scu.edu.cn [Department of Biomass Chemistry and Engineering, Sichuan University, Chengdu 610065 (China); He Qiang [National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065 (China); Shi Bi, E-mail: sibitannin@vip.163.com [National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065 (China) and Department of Biomass Chemistry and Engineering, Sichuan University, Chengdu 610065 (China)

2012-07-01

Bayberry tannin (BT), a typical plant polyphenol, was grafted on collagen fiber (CF) in different mass ratios. Subsequently, the BT-grafted CF (BT-CF) was used as carrier and stabilizer to prepare BT-CF stabilized silver nanoparticles (BT-CF-AgNPs). Scanning Electron Microscopy image of BT-CF-AgNPs showed that the BT-CF-AgNPs was in ordered fibrous state. X-ray Diffraction patterns and Transmission Electron Microscopy images offered evidence that the Ag nanoparticles were well dispersed on BT-CF. Fourier Transform-Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) investigations revealed that the Ag NPs were stabilized by the phenolic hydroxyls and quinones of BT on CF through electron donation/acception interaction. Antibacterial experiments demonstrated that BT-CF-AgNPs exhibited high antibacterial activity. When cell suspensions of Escherichia coli and Staphylococcus aureus (10{sup 4}-10{sup 5} cfu/mL) were contacted with BT{sub 0.19}-CF-AgNPs (mass ratio of BT to CF = 0.19, conc. of Ag = 8 {mu}g/mL) at 310 K under constant shaking, the number of cells went down to zero within 2 h. In addition, the minimal inhibitory concentration of BT{sub 0.19}-CF-AgNPs against Escherichia coli, Staphylococcus aureus, Penicillium glaucum and Saccharomyces cerevisiae was 2 {mu}g/mL, 4 {mu}g/mL, 6 {mu}g/mL and 12 {mu}g/mL Ag, respectively. During recycling use, the antibacterial activity of BT{sub 0.19}-CF-AgNPs against Escherichia coli can last for 5 cycles. These facts suggest that BT-CF-AgNPs can be used as a new and effective antibacterial agent. - Highlights: Black-Right-Pointing-Pointer Bayberry tannin-grafted collagen fiber can be acted as carrier and stabilizer for the preparation of nano-silver (AgNPs) with different particle size. Black-Right-Pointing-Pointer Bayberry tannin-grafted collagen fiber stabilized silver nanoparticles (BT-CF-AgNPs) were characterized by SEM, XRD, TEM, FTIR and XPS. Black-Right-Pointing-Pointer BT-CF-AgNPs has the

Chitinase activities, scab resistance, mycorrhization rates and biomass of own-rooted and grafted transgenic apple

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Tina Schäfer

2012-01-01

Full Text Available This study investigated the impact of constitutively expressed Trichoderma atroviride genes encoding exochitinase nag70 or endochitinase ech42 in transgenic lines of the apple cultivar Pinova on the symbiosis with arbuscular mycorrhizal fungi (AMF. We compared the exo- and endochitinase activities of leaves and roots from non-transgenic Pinova and the transgenic lines T386 and T389. Local and systemic effects were examined using own-rooted trees and trees grafted onto rootstock M9. Scab susceptibility was also assessed in own-rooted and grafted trees. AMF root colonization was assessed microscopically in the roots of apple trees cultivated in pots with artificial substrate and inoculated with the AMF Glomus intraradices and Glomus mosseae. Own-rooted transgenic lines had significantly higher chitinase activities in their leaves and roots compared to non-transgenic Pinova. Both of the own-rooted transgenic lines showed significantly fewer symptoms of scab infection as well as significantly lower root colonization by AMF. Biomass production was significantly reduced in both own-rooted transgenic lines. Rootstock M9 influenced chitinase activities in the leaves of grafted scions. When grafted onto M9, the leaf chitinase activities of non-transgenic Pinova (M9/Pinova and transgenic lines (M9/T386 and M9/T389 were not as different as when grown on their own roots. M9/T386 and M9/T389 were only temporarily less infected by scab than M9/Pinova. M9/T386 and M9/T389 did not differ significantly from M9/Pinova in their root chitinase activities, AMF root colonization and biomass.

Characterization of the Nutraceutical Quality and Antioxidant Activity in Bell Pepper in Response to Grafting

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Celia Chávez-Mendoza

2013-12-01

Full Text Available The grafting of fruits and vegetables influences fruit quality. The aim of the present work was to assess the effect of the rootstock and the scion on the antioxidant activity and the content in vitamin C, total phenols, lycopene and β-carotene of bell pepper. The cultivars Fascinato and Jeanette were used as scion and Terrano was used as rootstock. Four harvests in the production cycle of the vegetable were analyzed in a cultivation system under shading nets. The results indicate statistical differences in the content of these bioactive compounds between the varieties, between grafting and not grafting and between sampling dates (p ≤ 0.05. The vitamin C content, β-carotene, and antioxidant capacity proved significantly higher in Fascinato than in Janette. On average, grafting increased β-carotene and vitamin C concentrations and improved the antioxidant capacity, but had no influence on the total phenol or lycopene contents. It is concluded that grafting to the rootstock Terrano improves the nutritional quality of the fruit produced in both varieties of bell pepper studied.

Air Pump-Assisted Graft Centration, Graft Edge Unfolding, and Graft Uncreasing in Young Donor Graft Pre-Descemet Endothelial Keratoplasty.

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Jacob, Soosan; Narasimhan, Smita; Agarwal, Amar; Agarwal, Athiya; A I, Saijimol

2017-08-01

To assess an air pump-assisted technique for graft centration, graft edge unfolding, and graft uncreasing while performing pre-Descemet endothelial keratoplasty (PDEK) using young donor grafts. Continuous pressurized air infusion was used for graft centration, graft edge unfolding, and graft unwrinkling. Ten eyes of 10 patients underwent PDEK with donors aged below 40 years. In all eyes, the donor scrolled into tight scrolls. In all cases, the air pump-assisted technique was effective in positioning and centering the graft accurately and in straightening infolded graft edges and smoothing out graft creases and wrinkles. Endothelial cell loss was 38.6%. Postoperative best-corrected visual acuity at 6 months was 0.66 ± 0.25 in decimal equivalent. Continuous pressurized air infusion acted as a third hand providing a continuous pressure head that supported the graft and prevented graft dislocation as well as anterior chamber collapse during intraocular maneuvering. Adequate maneuvering space was available in all cases, and bleeding, if any, was tamponaded successfully in all cases. Although very young donor grafts may be used for PDEK, they are difficult to center and unroll completely before floating against host stroma. An air pump-assisted technique using continuous pressurized air infusion allows successful final graft positioning even with very young donor corneas. It thus makes surgery easier as several key steps are made easier to handle. It additionally helps in tamponading hemorrhage during peripheral iridectomy, increasing surgical space, preventing fluctuations in the anterior chamber depth, and promoting graft adherence.

Organosilane grafted acid-activated beidellite clay for the removal of non-ionic alachlor and anionic imazaquin

International Nuclear Information System (INIS)

Paul, Blain; Martens, Wayde N.; Frost, Ray L.

2011-01-01

Clay adsorbents were prepared via two-step method to remove nonionic alachlor and anionic imazaquin herbicides from water. Firstly, layered beidellite clay, a member of smectite family, was treated with acid in hydrothermal process; secondly, common silane coupling agents, 3-chloro-propyl trimethoxysilane or triethoxy silane, were grafted on the acid treated samples to prepare adsorbent materials. The organically modified clay samples were characterized by powder X-ray diffraction, N 2 gas adsorption, and FTIR spectroscopy. It was found that the selective modification of clay samples displayed higher adsorption capacity for herbicides compared with acid activated clay. And the amount of adsorption is increased with increasing the grafting amount of silane groups. Clay grafted with 3-chloro-propyl trimethoxysilane is an excellent adsorbent for both alachlor and imazaquin but triethoxy (octyl) silane grafted clay is more efficient only for alachlor removal.

Stent graft placement for dysfunctional arteriovenous grafts

Energy Technology Data Exchange (ETDEWEB)

Jeon, Gyeong Sik [Dept. of Radiology, CHA Bundang Medical Center, College of Medicine, CHA University, Seongnam (Korea, Republic of); Shin, Byung Seok; Ohm, Joon Young; Ahn, Moon Sang [Chungnam National University Hospital, Daejeon (Korea, Republic of)

2015-07-15

This study aimed to evaluate the usefulness and outcomes of stent graft use in dysfunctional arteriovenous grafts. Eleven patients who underwent stent graft placement for a dysfunctional hemodialysis graft were included in this retrospective study. Expanded polytetrafluoroethylene covered stent grafts were placed at the venous anastomosis site in case of pseudoaneurysm, venous laceration, elastic recoil or residual restenosis despite the repeated angioplasty. The patency of the arteriovenous graft was evaluated using Kaplan-Meier analysis. Primary and secondary mean patency was 363 days and 741 days. Primary patency at 3, 6, and 12 months was 82%, 73%, and 32%, respectively. Secondary patency at the 3, 6, 12, 24, and 36 months was improved to 91%, 82%, 82%, 50%, and 25%, respectively. Fractures of the stent graft were observed in 2 patients, but had no effect on the patency. Stent graft placement in dysfunctional arteriovenous graft is useful and effective in prolonging graft patency.

Studies on radiation-induced graft polymerization

International Nuclear Information System (INIS)

Omichi, Hideki

1978-09-01

Radiation-induced graft polymerization is used extensively to improve physical properties of polymers, but few processes are now commercialized. The reason for this is partly inadequate basic research on the reaction and partly the difficulty in developing the grafting process with large radiation source. Firstly, new techniques are proposed of studying kinetics of the graft polymerization in heterogeneous system. Based on the grafting yield, the molecular weight of graft chains, and the amount of radicals given by ESR and activation analysis, kinetic parameters are obtained and the reaction mechanism of grafting process is discussed. Secondly, the development of grafting process of poly (vinyl chloride)-butadiene is described. By study of the reaction, process design, construction and operation of the pilot plant, and economic analysis of the process, this process with 60 Co gamma ray sources is shown to be industrially promising. (author)

HPV16-E7-Specific Activated CD8 T Cells in E7 Transgenic Skin and Skin Grafts

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Seyed Davoud Jazayeri

2017-05-01

Full Text Available Human papillomavirus (HPV 16 E7 (E7 protein expression in skin promotes epithelial hyperproliferation and transformation to malignancy. Grafts of murine skin expressing E7 protein as a transgene in keratinocytes are not rejected from immunocompetent recipients, whereas grafts expressing ovalbumin (OVA, with or without coexpression of E7 protein, are promptly rejected, demonstrating that E7-associated non-antigen-specific local immunosuppression is not a major determinant of lack of rejection of E7 transgenic skin. To determine whether failure of rejection of E7 skin grafts is due to failure to attract E7-specific effector T cells, E7- and OVA-specific effector CD8+ T cells, activated in vitro, were transferred to animals bearing E7 transgenic skin grafts. Three days after T cell transfer, E7-specific T cells were present in significantly greater numbers than OVA-specific T cells in the grafted skin on animals bearing recently placed or healed E7 grafts, without graft rejection, and also in the ear skin of E7 transgenic animals, without obvious pathology. E7 and OVA-specific T cells were present in lesser numbers in healed E7 grafts than in recently placed grafts and in lesser numbers in recently placed E7 transgenic epidermal grafts without E7-associated hyperproliferation, derived from E7 transgenic mice with a mutated retinoblastoma gene. These data demonstrate that effector T cells are to some extent attracted to E7 transgenic skin specifically by E7 expression, but in large measure non-specifically by the epithelial proliferation associated with E7 expression, and by the local inflammation produced by grafting. Failure of E7 graft rejection was observed despite trafficking of E7-specific effector T cells to E7-expressing epithelium, a finding of consequence for immunotherapy of HPV 16 E7-associated human cancers.

Immobilization of urease on grafted starch by radiation method

International Nuclear Information System (INIS)

Nguyenanh Dung; Nguyendinh Huyen

1995-01-01

The acrylamide was grafted by radiation onto starch which is a kind of polymeric biomaterial. The urease was immobilized on the grafted starch. Some experiments to observe the quantitative relationships between the percent graft and the activity of immobilized enzyme were determined. The enzyme activity was maintained by more than seven batch enzyme reactions. (author)

Graft-Sparing Strategy for Thoracic Prosthetic Graft Infection.

Science.gov (United States)

Uchino, Gaku; Yoshida, Takeshi; Kakii, Bunpachi; Furui, Masato

2018-04-01

 Thoracic prosthetic graft infection is a rare but serious complication with no standard management. We reported our surgical experience on graft-sparing strategy for thoracic prosthetic graft infection.  This study included patients who underwent graft-sparing surgery for thoracic prosthetic graft infection at Matsubara Tokushukai Hospital in Japan from January 2000 to October 2017.  There were 17 patients included in the analyses, with a mean age at surgery of 71.0 ± 10.5 years; 11 were men. In-hospital mortality was observed in five patients (29.4%).  Graft-sparing surgery for thoracic prosthetic graft infection is an alternative option particularly for early graft infection after hemiarch replacement. Georg Thieme Verlag KG Stuttgart · New York.

Spatial and temporal distribution of root activity of Ramphal (Annona reticulata) seedlings and their grafts with 'Arka Sahan' scion determined using isotopic technique

International Nuclear Information System (INIS)

Kotur, S.C.

2009-01-01

In both seedlings and grafts of Ramphal, early rainy season showed the highest intensity of root activity followed by late rainy season and winter. During early rainy season, the active roots were predominantly surface oriented and clustered towards the trunk in both seedlings and grafts. During later seasons, however, the roots migrated from 20cm to 40cm depth and from 40cm to 80 and 120cm radial distance that resulted in a uniform distribution of active roots throughout the rooting volume. The grafts of 'Arka Sahan' scion on Ramphal rootstocks showed deeper root activity which had nearly one-half of active roots close to the trunk at 40cm distance, that may be more drought tolerant than the seedlings. (author)

Skin graft

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Skin transplant; Skin autografting; FTSG; STSG; Split thickness skin graft; Full thickness skin graft ... donor site. Most people who are having a skin graft have a split-thickness skin graft. This takes ...

Evolution of skin grafting for treatment of burns: Reverdin pinch grafting to Tanner mesh grafting and beyond.

Science.gov (United States)

Singh, Mansher; Nuutila, Kristo; Collins, K C; Huang, Anne

2017-09-01

Skin grafting is the current standard care in the treatment of full thickness burns. It was first described around 1500 BC but the vast majority of advancements have been achieved over the past 200 years. An extensive literature review was conducted on Pubmed, Medline and Google Scholar researching the evolution of skin grafting techniques. The authors concentrated on the major landmarks of skin grafting and also provide an overview of ongoing research efforts in this field. The major innovations of skin grafting include Reverdin pinch grafting, Ollier grafting, Thiersch grafting, Wolfe grafting, Padgett dermatome and modifications, Meek-wall microdermatome and Tanner mesh grafting. A brief description of the usage, advantages and limitations of each technique is included in the manuscript. Skin grafting technique have evolved significantly over past 200 years from Reverdin pinch grafting to modern day meshed skin grafts using powered dermatome. Increasing the expansion ratio and improving the cosmetic and functional outcome are the main focus of ongoing skin grafting research and emerging techniques (such as Integra ® , Recell ® , Xpansion ® ) are showing promise. Copyright © 2017 Elsevier Ltd and ISBI. All rights reserved.

Graft intolerance syndrome requiring graft nephrectomy after late kidney graft failure: can it be predicted? A retrospective cohort study.

Science.gov (United States)

Bunthof, Kim L W; Verhoeks, Carmen M; van den Brand, Jan A J G; Hilbrands, Luuk B

2018-02-01

Graft nephrectomy is recommended in case of early graft failure. When the graft fails more than 3-6 months after transplantation, it is current practice to follow a wait-and-see policy. A common indication for graft removal is the graft intolerance syndrome. We aimed to create a risk prediction model for the occurrence of graft intolerance resulting in graft nephrectomy. We collected data of kidney transplantations performed in our center between 1980 and 2010 that failed at least 6 months after transplantation. We evaluated the association between baseline characteristics and the occurrence of graft nephrectomy because of graft intolerance using a competing risk regression model. Prognostic factors were included in a multivariate prediction model. In- and exclusion criteria were met in 288 cases. In 48 patients, the graft was removed because of graft intolerance. Donor age, the number of rejections, and shorter graft survival were predictive factors for graft nephrectomy because of the graft intolerance syndrome. These factors were included in a prediction rule. Using donor age, graft survival, and the number of rejections, clinicians can predict the need for graft nephrectomy with a reasonable accuracy. © 2017 Steunstichting ESOT.

Aortic Graft Infection Secondary to Iatrogenic Transcolonic Graft Malposition.

Science.gov (United States)

Blank, Jacqueline J; Rothstein, Abby E; Lee, Cheong Jun; Malinowski, Michael J; Lewis, Brian D; Ridolfi, Timothy J; Otterson, Mary F

2018-01-01

Aortic graft infections are a rare but devastating complication of aortic revascularization. Often infections occur due to contamination at the time of surgery. Iatrogenic misplacement of the limbs of an aortobifemoral graft is exceedingly rare, and principles of evaluation and treatment are not well defined. We report 2 cases of aortobifemoral bypass graft malposition through the colon. Case 1 is a 54-year-old male who underwent aortobifemoral bypass grafting for acute limb ischemia. He had previously undergone a partial sigmoid colectomy for diverticulitis. Approximately 6 months after vascular surgery, he presented with an occult graft infection. Preoperative imaging and intraoperative findings were consistent with graft placement through the sigmoid colon. Case 2 is a 60-year-old male who underwent aortobifemoral bypass grafting due to a nonhealing wound after toe amputation. His postoperative course was complicated by pneumonia, bacteremia thought to be secondary to the pneumonia, general malaise, and persistent fevers. Approximately 10 weeks after the vascular surgery, he presented with imaging and intraoperative findings of graft malposition through the cecum. Aortic graft infection is usually caused by surgical contamination and presents as an indolent infection. Case 1 presented as such; Case 2 presented more acutely. Both grafts were iatrogenically misplaced through the colon at the index operation. The patients underwent extra-anatomic bypass and graft explantation and subsequently recovered.

Grafting

Energy Technology Data Exchange (ETDEWEB)

Garnett, J L [New South Wales Univ., Kensington (Australia). School of Chemistry

1979-01-01

The unique value of ionizing radiation for the initiation of grafting to backbone polymers is discussed. The principles of the technique are briefly reviewed. The conditions under which free radicals and ions participate in these reactions are examined. Examples of representative grafting processes are considered to illustrate where the technique can be of potential commercial value to a wide range of industries. The general principles of these grafting reactions are shown to be applicable to radiation induced rapid cure technology such as is provided by electron beam processing facilities. Grafting reactions initiated by UV are also treated and shown to be of importance because of the many similarities in properties of the ionizing radiation and UV systems, also the rapid industrial exploitation of EB and sensitized UV processing technology. Possible future trends in radiation grafting are outlined.

Albumin grafting on biomaterial surfaces using gamma-irradiation

International Nuclear Information System (INIS)

Kamath, K.R.

1993-01-01

Surface modification has been used extensively in various fields to introduce desirable surface properties without affecting the bulk properties of the material. In the area of biomaterials, the approach of surface modification offers an effective alternative to the synthesis of new biomaterials. The specific objective of this study was to modify different biomaterial surfaces by albumin grafting to improve their blood compatibility. The modified surfaces were characterized for surface-induced platelet activation and thrombus formation. This behavior was correlated with the conditions used for grafting. In particular, albumin was functionalized to introduce pendant double bonds into the molecule. The functionalized albumin was covalently attached to various surfaces, such as dimethyldichlorosilane-coated glass, polypropylene, polycarbonate, poly(vinyl chloride), and polyethylene by gamma-irradiation. Platelet adhesion and activation on these surfaces was examined using video microscopy and scanning electron microscopy. The extent of grafting was found to be dependent on the albumin concentration used for adsorption and the gamma-irradiation time. Release of the grafted albumin during exposure to blood was minimal. The albumin-grafted fibers maintained their thromboresistant properties even after storage at elevated temperatures for prolonged time periods. Finally, the approach was used to graft albumin on the PLEXUS Adult Hollow Fiber Oxygenators (Shiley). The blood compatibility of the grafted oxygenators improved significantly when compared to controls

Effect of ultraviolet B irradiation on delayed-type hypersensitivity, cytotoxic T lymphocyte activity, and skin graft rejection

International Nuclear Information System (INIS)

Tamaki, K.; Iijima, M.

1989-01-01

The influence of ultraviolet B irradiation on the induction of delayed-type hypersensitivity reactions to alloantigens by epidermal cells (EC), on the generation of cytotoxic T lymphocyte activity to alloantigens, and on skin graft rejection was studied. After the skin was irradiated with UVB in vitro, EC were obtained. The EC were injected subcutaneously, and the DTH reaction was compared with that induced by non-UVB-irradiated EC. A reduction in the DTH reaction was observed (from 62% to 99.1%). CTL activity in these mice was assessed after in vitro stimulation. CTL activity in mice sensitized with UVB-irradiated EC was significantly reduced. Furthermore, mice sensitized with UVB-irradiated EC did not reject a subsequent skin allograft in an accelerated fashion, whereas mice sensitized with non-UVB-irradiated EC did. The mechanism(s) of these reactions and the clinical application of the UVB irradiation prior to grafting are discussed

Grafting and curing

International Nuclear Information System (INIS)

Garnett, J.L.; Loo-Teck Ng; Visay Viengkhou

1998-01-01

Progress in radiation grafting and curing is briefly reviewed. The two processes are shown to be mechanistically related. The parameters influencing yields are examined particularly for grafting. For ionising radiation grafting systems (EB and gamma ray) these include solvents, substrate and monomer structure, dose and dose-rate, temperature and more recently role of additives. In addition, for UV grafting, the significance of photoinitiators is discussed. Current applications of radiation grafting and curing are outlined. The recent development of photoinitiator free grafting and curing is examined as well as the potential for the new excimer laser sources. The future application of both grafting and curing is considered, especially the significance of the occurrence of concurrent grafting during cure and its relevance in environmental considerations

Evaluation of 99mTc-MDP bone imaging in monitoring the muscle-pedicle bone graft osteogenic activation

International Nuclear Information System (INIS)

Sang Shibiao; Wu Yiwei; Zhang Wei; Jiang Yimin; Chen Guangxiang; Dong Tianhua

2002-01-01

Nine mature and healthy dogs were divided into 4 groups randomly. The first group consists of 3 dogs, and the rest groups, 2 dogs. Self-control way was used. The left ilium was the experimental site, where the bone piece with sartorial muscle attached was cut from ilium. The right side served as control, where the graft bone from ilium was wrapped up with silica gel, then fixed subcutaneously. The pedicled bone pieces were retrieved in 2, 4, 6, 8 weeks after surgery, the size of graft bones from two sides were the same. Survival range, osteogenic formation of muscle-pedicle bone were examined by 99m Tc-MDP bone imaging and histological method to evaluate the clinical value of treatment of ischemic osteonecrosis of the femoral head with muscle-pedicle bone grafting. The results were as follows: 1. The part of bone attached by the sartorial survived, but osteonecrosis was observed at the location of 1.2-1.7 cm from attached point of muscle. 2. There were two forms observed in the course of osteogenic activation of muscle-pedicle bone. Under the reduction of mechanical stimulation and blood supply, bone marrow tissue was replaced by fibro-granulation tissue and new capillary in the survival part, while the survival bone of proximal part grew distally and gradually replace the dead bone of distal part. 3. Histological examination revealed that small amounts of fibro-granulation tissue and new capillary appeared in 2nd week, primary trabeculae appeared in 6th week, and in 8th week, some trabeculae recovered their normal appearance and osteogenic cell reduced remarkably. 4. Survival range of muscle-pedicle graft bone was directly proportional to the width of muscle pedicle. Therefore, radionuclide bone imaging and histological examination demonstrated that muscle-pedicle graft bone was a piece of bone with relatively poor blood supply, its effect is repairing necrosis and collapse of the femoral head is limited. 99m Tc-MDP bone imaging may be an effective and first

Immobilized enzymes in blood plasma exchangers via radiation grafting

Science.gov (United States)

Gombotz, Wayne; Hoffman, Allan; Schmer, Gottfried; Uenoyama, Satoshi

The enzyme asparaginase was immobilized onto a porous hollow polypropylene (PP) fiber blood plasma exchange device for the treatment of acute lymphocytic leukemia. The devices were first radiation grafted with polymethacrylic acid (poly(MAAc)). This introduces carboxyl groups onto the surface of the fibers. Several variables were studied in the grafting reaction including the effects of solvent type and monomer concentration. The carboxyl groups were activated with N-hydroxy succinimide (NHS) using carbodiimide chemistry. Asparaginase was then covalently immobilized on the activated surfaces. Quantitative relationships were found relating the percent graft to the amount of immobilized enzyme which was active. The enzyme reactor was tested both in vitro and in vivo using a sheep as an animal model.

Grafting the alar rim: application as anatomical graft.

Science.gov (United States)

Gruber, Ronald P; Fox, Paige; Peled, Anne; Belek, Kyle A

2014-12-01

Alar rim contour and alar rim grafts have become essential components of rhinoplasty. Ideally, grafts of the nose should be anatomical in shape. So doing might make grafts of the alar rim more robust. The authors considered doing that by applying the graft as a continuous extension of the lateral crus. Twelve patients (two men and 10 women) constituted the study group (seven primary and five secondary cases). Of those, there were five concave rims, two concave rims with rim retraction, two boxy tips, and three cephalically oriented lateral crura. Surgical technique included the following: (1) an open approach was used; (2) a marginal incision that ignored the caudal margin of the lateral crus (the incision went straight posteriorly to a point 5 to 6 mm from the rim margin) was used; (3) a triangular graft was made to cover the exposed vestibular skin; (4) it was secured end to end to the caudal border of the lateral crus; and (5) the poster end was allowed to sit in a small subcutaneous pocket. Follow-up was 11 to 19 months. All 12 patients exhibited good rims as judged by a blinded panel. Rim retraction was not fully corrected in one patient, but no further treatment was required. One patient did require a secondary small rim graft for residual rim concavity. The concept of grafting the alar rim is strongly supported by the authors' results. The modifications the authors applied by designing the graft to be anatomical in shape has been a technical help.

Experimental study of vascularized nerve graft: evaluation of nerve regeneration using choline acetyltransferase activity.

Science.gov (United States)

Iwai, M; Tamai, S; Yajima, H; Kawanishi, K

2001-01-01

A comparative study of nerve regeneration was performed on vascularized nerve graft (VNG) and free nerve graft (FNG) in Fischer strain rats. A segment of the sciatic nerve with vascular pedicle of the femoral artery and vein was harvested from syngeneic donor rat for the VNG group and the sciatic nerve in the same length without vascular pedicle was harvested for the FNG group. They were transplanted to a nerve defect in the sciatic nerve of syngeneic recipient rats. At 2, 4, 6, 8, 12, 16, and 24 weeks after operation, the sciatic nerves were biopsied and processed for evaluation of choline acetyltransferase (CAT) activity, histological studies, and measurement of wet weight of the muscle innervated by the sciatic nerve. Electrophysiological evaluation of the grafted nerve was also performed before sacrifice. The average CAT activity in the distal to the distal suture site was 383 cpm in VNG and 361 cpm in FNG at 2 weeks; 6,189 cpm in VNG and 2,264 cpm in FNG at 4 weeks; and 11,299 cpm in VNG and 9,424 cpm in FNG at 6 weeks postoperatively. The value of the VNG group was statistically higher than that of the FNG group at 4 weeks postoperatively. Electrophysiological and histological findings also suggested that nerve regeneration in the VNG group was superior to that in the FNG group during the same period. However, there was no significant difference between the two groups after 6 weeks postoperatively in any of the evaluations. The CAT measurement was useful in the experiments, because it was highly sensitive and reproducible. Copyright 2001 Wiley-Liss, Inc.

Thermal degradation kinetics and estimation of lifetime of radiation grafted polypropylene films

International Nuclear Information System (INIS)

Mandal, Dev K.; Bhunia, Haripada; Bajpai, Pramod K.; Bhalla, Vinod Kumar

2017-01-01

In this research work, thermal stability and degradation behavior of acrylic acid grafted polypropylene (PP-g-PAAc) films were investigated by using thermogravimetric (TGA) analysis at four different heating rates 5, 10, 15 and 20 °C/min over a temperature range of 40–550 °C in nitrogen atmosphere. The kinetic parameters namely activation energy (E a ), reaction order (n) and frequency factor (Z) were calculated by three multiple heating rate methods. The thermal stability of PP-g-PAAc films is found to decrease with increase in degree of grafting. The TGA data and thermal kinetic parameters were also used to predict the lifetime of grafted PP films. The estimated lifetime of neat PP as well as grafted PP decreased with increase in temperature by all the three methods. Studies also indicated that E a and lifetime of PP-g-PAAc films decreased with increase in degree of grafting, which may also be helpful in biodegradation of grafted PP films. - Highlights: • Thermal stability of grafted polypropylene films have been observed lower than for neat polypropylene film. • Multiple heating rate methods have been used for determination of activation energy. • Activation energies of grafted polypropylene films were lower than polypropylene film. • The lifetimes of grafted polypropylene films were shorter than for neat polypropylene film.

[Features of skin graft in pediatric plastic surgery].

Science.gov (United States)

Depoortère, C; François, C; Belkhou, A; Duquennoy-Martinot, V; Guerreschi, P

2016-10-01

Skin graft is a skin tissue fragment transferred from a donor site to a receiving site with a spontaneous revascularization. Basic process of plastic surgery, skin graft known in children, specific, warnings and refinements. It finds its indication in many pediatric cases: integumental diseases (neavus, hamartoma), acute burns and scars, traumatic loss of substance or surgically induced, congenital malformations of the hands and feet, etc. Specific skin graft techniques in children are developed: donor sites, sampling technique and procedure, early postoperative care. Especially in children, the scalp is a perfect site for split skin graft and technique is actively developed. Refinements and special cases are discussed: use of dermal matrices, allografts, xenografts, negative pressure therapy, prior skin expansion of the donor site. Results of skin graft in children are exposed: taking of graft, growth and shrinkage, pigmentation. Skin graft sometimes allows to stay the complex movement and get the best final benefit, permanent or at least temporary, in a growing being. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Radiation grafting from binary monomer mixtures. II. Vinyl ether of monoethanolamine and N-vinylpyrrolidone

International Nuclear Information System (INIS)

Nurkeeva, Zauresh S.; Abdel Aal, A.-S.; Kupchishin, Anatoliy I.; Khutoryanskiy, Vitaliy V.; Mun, Grigoriy A.; Beksyrgaeva, Aida G.

2003-01-01

Radiation grafting from binary monomer mixtures of vinyl ether of monoethanolamine and N-vinylpyrrolidone onto polyethylene films has been studied. The structure of the grafted films was characterized by FTIR spectroscopy. Water uptake and contact angle measurements confirmed that the grafting leads to a considerable hydrophilization of the films surface. The presence of the more active N-vinylpyrrolidone enhances the grafting of the less active vinyl ether of monoethanolamine. Sorption properties of grafted films with respect to copper (II) ions have been studied

Long-term activity of covalent grafted biocatalysts during intermittent use of a glucose/O2 biofuel cell

International Nuclear Information System (INIS)

Merle, G.; Habrioux, A.; Servat, K.; Rolland, M.; Innocent, C.; Kokoh, K.B.; Tingry, S.

2009-01-01

The operational stability of enzymes in a concentric glucose/O 2 biofuel cell has been significantly improved with the synthesis of grafted enzyme electrodes compared to entrapped enzyme electrodes. The concentric device combined glucose electro-oxidation by glucose oxidase at the anode and oxygen electro-reduction by bilirubin oxidase at the cathode. The entrapped enzyme electrodes were prepared from physical immobilization of the enzymes by a polypyrrole polymer onto the electrode surface. The grafted enzyme electrodes were synthesized by grafting the enzymes via alkyl spacer arms to a poly(aminopropylpyrrole) film onto the electrode surface. From spectrophotometric and electrochemical analyses, it was demonstrated that the spacer arms increased the operational stability and enzyme mobility that favoured electron transfer from their active sites to the electrode. The maximum power output of the assembled biofuel cell was 20 μW cm -2 , at 0.20 V with 10 mM glucose in phosphate buffer pH 7.4. The grafted enzyme electrodes presented an unprecedented operational stability as the maximum of power density of the BFC remains constant after intermittent use over a 45-day period. This was a remarkable improvement compared to electrodes with entrapped enzymes, which lost 74% of their initial power density after intermittent use over a 17-day period

Nanofat grafting under a split-thickness skin graft for problematic wound management.

Science.gov (United States)

Kemaloğlu, Cemal Alper

2016-01-01

Obesity and certain medical disorders make the reconstruction of skin defects challenging. Different kind of procedure can be used for these defect, besides, skin grafting is one of the most common and simplest procedure. Fat grafting and stem cells which are located in the adipose tissue have been commonly used in plastic surgery for regeneration and rejuvenation purposes. To decrease graft failure rate we performed nanofat grafting under an autologous split-thickness skin graft in our patient who had a problematic wound. The case of a 35-year-old female patient with a traumatic skin defect on her left anterior crural region is described herein. After subsequent flap reconstruction, the result was disappointing and the defect size was widened. The defect was treated with combined grafting (nanofat grafting under an autologous split-thickness skin graft). At the 6 months follow-up assessment after combined grafting, the integrity of the skin graft was good with excellent pliability. Combined grafting for problematic wounds seems to be a useful technique for cases requiring reconstruction. The potential existence of stem cells may be responsible for the successful result in our patient.

Effect of bidispersity in grafted chain length on grafted chain conformations and potential of mean force between polymer grafted nanoparticles in a homopolymer matrix.

Science.gov (United States)

Nair, Nitish; Wentzel, Nathaniel; Jayaraman, Arthi

2011-05-21

In efforts to produce polymeric materials with tailored physical properties, significant interest has grown around the ability to control the spatial organization of nanoparticles in polymer nanocomposites. One way to achieve controlled particle arrangement is by grafting the nanoparticle surface with polymers that are compatible with the matrix, thus manipulating the interfacial interactions between the nanoparticles and the polymer matrix. Previous work has shown that the molecular weight of the grafted polymer, both at high grafting density and low grafting density, plays a key role in dictating the effective inter-particle interactions in a polymer matrix. At high grafting density nanoparticles disperse (aggregate) if the graft molecular weight is higher (lower) than the matrix molecular weight. At low grafting density the longer grafts can better shield the nanoparticle surface from direct particle-particle contacts than the shorter grafts and lead to the dispersion of the grafted particles in the matrix. Despite the importance of graft molecular weight, and evidence of non-trivial effects of polydispersity of chains grafted on flat surfaces, most theoretical work on polymer grafted nanoparticles has only focused on monodisperse grafted chains. In this paper, we focus on how bidispersity in grafted chain lengths affects the grafted chain conformations and inter-particle interactions in an implicit solvent and in a dense homopolymer polymer matrix. We first present the effects of bidispersity on grafted chain conformations in a single polymer grafted particle using purely Monte Carlo (MC) simulations. This is followed by calculations of the potential of mean force (PMF) between two grafted particles in a polymer matrix using a self-consistent Polymer Reference Interaction Site Model theory-Monte Carlo simulation approach. Monte Carlo simulations of a single polymer grafted particle in an implicit solvent show that in the bidisperse polymer grafted particles

Granular activated carbon with grafted nanoporous polymer enhances nanoscale zero-valent iron impregnation and water contaminant removal

DEFF Research Database (Denmark)

Mines, Paul D.; Uthuppu, Basil; Thirion, Damien

2018-01-01

Granular activated carbon was customized with a chemical grafting procedure of a nanoporous polymeric network for the purpose of nanoscale zero-valent iron impregnation and subsequent water contaminant remediation. Characterization of the prepared composite material revealed that not only was the...

Bone grafting: An overview

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D. O. Joshi

2010-08-01

Full Text Available Bone grafting is the process by which bone is transferred from a source (donor to site (recipient. Due to trauma from accidents by speedy vehicles, falling down from height or gunshot injury particularly in human being, acquired or developmental diseases like rickets, congenital defects like abnormal bone development, wearing out because of age and overuse; lead to bone loss and to replace the loss we need the bone grafting. Osteogenesis, osteoinduction, osteoconduction, mechanical supports are the four basic mechanisms of bone graft. Bone graft can be harvested from the iliac crest, proximal tibia, proximal humerus, proximal femur, ribs and sternum. An ideal bone graft material is biologically inert, source of osteogenic, act as a mechanical support, readily available, easily adaptable in terms of size, shape, length and replaced by the host bone. Except blood, bone is grafted with greater frequency. Bone graft indicated for variety of orthopedic abnormalities, comminuted fractures, delayed unions, non-unions, arthrodesis and osteomyelitis. Bone graft can be harvested from the iliac crest, proximal tibia, proximal humerus, proximal femur, ribs and sternum. By adopting different procedure of graft preservation its antigenicity can be minimized. The concept of bone banking for obtaining bone grafts and implants is very useful for clinical application. Absolute stability require for successful incorporation. Ideal bone graft must possess osteogenic, osteoinductive and osteocon-ductive properties. Cancellous bone graft is superior to cortical bone graft. Usually autologous cancellous bone graft are used as fresh grafts where as allografts are employed as an alloimplant. None of the available type of bone grafts possesses all these properties therefore, a single type of graft cannot be recomm-ended for all types of orthopedic abnormalities. Bone grafts and implants can be selected as per clinical problems, the equipments available and preference of

Corneal Graft Rejection: Incidence and Risk Factors

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Alireza Baradaran-Rafii

2008-12-01

Full Text Available

PURPOSE: To determine the incidence and risk factors of late corneal graft rejection after penetrating keratoplasty (PKP. METHODS: Records of all patients who had undergone PKP from 2002 to 2004 without immunosuppressive therapy other than systemic steroids and with at least one year of follow up were reviewed. The role of possible risk factors such as demographic factors, other host factors, donor factors, indications for PKP as well as type of rejection were evaluated. RESULTS: During the study period, 295 PKPs were performed on 286 patients (176 male, 110 female. Mean age at the time of keratoplasty was 38±20 (range, 40 days to 90 years and mean follow up period was 20±10 (range 12-43 months. Graft rejection occurred in 94 eyes (31.8% at an average of 7.3±6 months (range, 20 days to 39 months after PKP. The most common type of rejection was endothelial (20.7%. Corneal vascularization, regrafting, anterior synechiae, irritating sutures, active inflammation, additional anterior segment procedures, history of trauma, uncontrolled glaucoma, prior graft rejection, recurrence of herpetic infection and eccentric grafting increased the rate of rejection. Patient age, donor size and bilateral transplantation had no significant influence on graft rejection. CONCLUSION: Significant risk factors for corneal graft rejection include

Radiation-induced grafting of acrylic acid onto polyethylene filaments

International Nuclear Information System (INIS)

Kaji, K.; Sakurada, I.; Okada, T.

1981-01-01

Radiation-induced grafting of acrylic acid onto high density polyethylene (PE) filaments was carried out in order to raise softening temperature and impart flame retardance and hydrophilic properties. Mutual γ-irradiation method was employed for the grafting in a mixture of acrylic acid (AA), ethylene dichloride and water containing a small amount of ferrous ammonium sulfate. The rate of grafting was very low at room temperature. On the other hand, large percent grafts were obtained when the grafting was performed at an elevated temperature. Activation energy for the initial rate of grafting was found to be 17 kcal/mol between 20 and 60 0 C and 10 kcal/ mol between 60 and 80 0 C. Original PE filament begins to shrink at 70 0 C, shows maximum shrinkage of 50% at 130 0 C and then breaks off at 136 0 C. When a 34% AA graft is converted to metallic salt the graft filament retains its filament form even above 300 0 C and gives maximum shrinkage of 15%. Burning tests by a wire-netting basket method indicate that graft filaments and their metallic salts do not form melting drops upon burning and are self-extinguishing. Original PE filament shows no moisture absorption; however, that of AA-grafted PE increases with increasing graft percent. (author)

Preparation of metal ion exchange resin by radiation-induced graft copolymerization

International Nuclear Information System (INIS)

Nakase, Yoshiaki; Akasaka, Nobuhiro.

1982-06-01

Radiation-induced graft copolymerization of 2-acrylamide-2-methyl propane sulfonic acid (AMPS) onto polyvinylchloride (PVC) and polyvinylidene chloride resin (PVD) was investigated in the water-acetone system and their adsorptive activities to metal ion were also examined. In the case of PVC, the degree of grafting increased with the increase of acetone content, but the adsorptive activity to metal ions (mainly lithic ion) became maximum in the system with water/acetone of 2/3. Grafted PVC prepared at about 35 0 C and at a higher concentration of AMPS showed higher adsorption activity than the other cases. In the case of PVD, a similar result was obtained with the case of PVC except the temperature dependence and effect of swelling agent. Polymerizations at temperatures of 35 and 50 0 C showed no effect on the degree of grafting, and the usage of a swelling agent was quite effective to the adsorptive activity. Glass transition temperature of the grafted copolymer was the same as that of original polymer, and their thermal stability was confirmed up to the temperature at which homopolymer of AMPS decomposed, about 180 0 C. (author)

Arteriovenous shunt graft ulceration with sinus and graft epithelialization

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Pooja Singhal

2015-03-01

Full Text Available Arteriovenous fistula and grafts are used as access sites for patients with chronic kidney disease and are prone for complications. Stent grafts are used to treat access site complications. We report a rare and unusual finding of epithelialization of the sinus tract and the lumen of a polytetrafluoroethylene graft, following ulceration of the overlying skin.

Role of graft oversizing in the fixation strength of barbed endovascular grafts.

Science.gov (United States)

Kratzberg, Jarin A; Golzarian, Jafar; Raghavan, Madhavan L

2009-06-01

The role of endovascular graft oversizing on risk of distal graft migration following endovascular aneurysm repair for abdominal aortic aneurysm is poorly understood. A controlled in vitro investigation of the role of oversizing in graft-aorta attachment strength for endovascular grafts (EVGs) with barbs was performed. Barbed stent grafts (N = 20) with controlled graft oversizing varying from 4-45% were fabricated while maintaining other design variables unchanged. A flow loop with physiological flow characteristics and a biosynthetic aortic aneurysm phantom (synthetic aneurysm model with a bovine aortic neck) were developed. The stent grafts were deployed into the aortic neck of the bio-synthetic aortic aneurysm phantom under realistic flow conditions. Computed tomography imaging of the graft-aorta complex was used to document attachment characteristics such as graft apposition, number of barbs penetrated, and penetration depth and angle. The strength of graft attachment to the aortic neck was assessed using mechanical pullout testing. Stent grafts were categorized into four groups based on oversizing: 4-10%; 11-20%; 21-30%; and greater than 30% oversizing. Pullout force, a measure of post-deployment fixation strength was not different between 4-10% (6.23 +/- 1.90 N), 11-20% (6.25 +/- 1.84 N) and 20-30% (5.85 +/- 1.89 N) groups, but significantly lower for the group with greater than 30% oversizing (3.67 +/- 1.41 N). Increasing oversizing caused a proportional decrease in the number of barbs penetrating the aortic wall (correlation = -0.83). Of the 14 barbs available in the stent graft, 89% of the barbs (12.5 of 14 on average) penetrated the aortic wall in the 4-10% oversizing group while only 38% (5.25 of 14) did for the greater than 30% group (P barb penetration were found to be positively correlated to pullout force. Greater than 30% graft oversizing affects both barb penetration and graft apposition adversely resulting in a low pullout force in this in vitro

Surface grafted polymer brushes: potential applications in dengue biosensors

Energy Technology Data Exchange (ETDEWEB)

Baratela, Fernando Jose Costa; Higa, Olga Zazuco, E-mail: ozahiga@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Faria, Henrique Antonio Mendonca de; Queiroz, Alvaro Antonio Alencar de, E-mail: alencar@unifei.edu.br [Universidade Federal de Itajuba (UNIFEI), Itajuba, MG (Brazil). Instituto de Fisica e Quimica

2013-07-01

A polymer brush membrane-based ultrasensitive biosensor for dengue diagnosis was constructed using poly(hydroxyethyl methacrylate) (PHEMA) brushes immobilized onto low density polyethylene (LDPE) films. LDPE surface films were initially modified by Ar{sup +} ion irradiation to activate the polymer surface. Subsequently, graft polymerization of 2-hydroxyethyl methacrylate onto the activated LDPE surface was carried out under aqueous conditions to create patterned polymer brushes of PHEMA. The grafted PHEMA brushes were characterized by Fourier transform-infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and contact angle analysis. The SEM observations showed that selective surface activation with Ar+ implantation and graft polymerization on the selectively activated surface had occurred. The PHEMA brushes were electrically characterized in the presence of concentrations of human immunoglobulin (IgG). The proposed amperometric biosensor was successfully used for determination of IgG in physiologic samples with excellent responses. (author)

Surface grafted polymer brushes: potential applications in dengue biosensors

International Nuclear Information System (INIS)

Baratela, Fernando Jose Costa; Higa, Olga Zazuco; Faria, Henrique Antonio Mendonca de; Queiroz, Alvaro Antonio Alencar de

2013-01-01

A polymer brush membrane-based ultrasensitive biosensor for dengue diagnosis was constructed using poly(hydroxyethyl methacrylate) (PHEMA) brushes immobilized onto low density polyethylene (LDPE) films. LDPE surface films were initially modified by Ar + ion irradiation to activate the polymer surface. Subsequently, graft polymerization of 2-hydroxyethyl methacrylate onto the activated LDPE surface was carried out under aqueous conditions to create patterned polymer brushes of PHEMA. The grafted PHEMA brushes were characterized by Fourier transform-infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and contact angle analysis. The SEM observations showed that selective surface activation with Ar+ implantation and graft polymerization on the selectively activated surface had occurred. The PHEMA brushes were electrically characterized in the presence of concentrations of human immunoglobulin (IgG). The proposed amperometric biosensor was successfully used for determination of IgG in physiologic samples with excellent responses. (author)

Bone Graft Alternatives

Science.gov (United States)

... Spine Treatment Spondylolisthesis BLOG FIND A SPECIALIST Treatments Bone Graft Alternatives Patient Education Committee Patient Education Committee ... procedure such as spinal fusion. What Types of Bone Grafts are There? Bone grafts that are transplanted ...

Graft irradiation abrogates graft-versus-host disease in combined pancreas-spleen transplantation

International Nuclear Information System (INIS)

Schulak, J.A.; Sharp, W.J.

1986-01-01

A model of combined pancreas-spleen transplantation (PST) was studied in LBN F1 recipients of Lewis grafts in order to evaluate the efficacy of pretransplant graft irradiation in preventing lethal graft-versus-host disease (GVHD). Recipients of unmodified PST uniformly developed severe GVHD and died (MST = 16.7 +/- 3.8 days). Whole body donor irradiation with either 500 or 250 rad prevented lethal GVHD. Similarly, ex vivo graft irradiation with either 1000 or 500 rad also resulted in normal weight gain, graft function, and host survival for the 6-week study period. Conversely, delay of graft irradiation until 3 days after transplantation failed to prevent this complication (MST = 15.8 +/- 3.7 days). Recipients of irradiated grafts displayed glucose tolerance tests that were identical to those in the control group indicating that the doses of radiation employed in these experiments were not deleterious to islet function. Irradiated spleen grafts appeared histologically normal at 6 weeks after transplantation. Cells derived from these grafts failed to stimulate lymph node enlargement in a popliteal lymph node assay for GVHD, suggesting that these spleens may have become repopulated with host cells. These experiments confirm that PST has the potential to cause lethal GVHD and suggest that pretransplant graft irradiation may be used to prevent its occurrence

Effect of Grafting Method, Graft Cover and Foliar Spray of some Mineral Elements on Persian Walnut Graft-take and Winter Survival Rate

Directory of Open Access Journals (Sweden)

Reza Rezaee

2017-09-01

Full Text Available Introduction: Persian walnut (Juglans regia L. is an important nut crop in Iran and many parts of the world. One of the major challenges of growing walnut is planting of non-grafted walnut trees in orchards, which leads to the reduction of yield, quality and productivity of walnut orchards. Compared to the other fruit trees, walnut grafting is difficult and even newly grafted walnut seedlings are vulnerable to fall or winter frost chilling, so that most of the seedlings are lost after subjecting to the cold winter. There are a few studies reporting successful grafting in outdoor conditions, however, final grafting take after winter has been usually ignored. Hence, increased walnut grafting success and improved tree growth after grafting through foliar nutrient application may lead to increased tolerance of chilling. Therefore, main goals of this research were to investigate the effect of some graft covers and role of foliar spray of calcium, boron and zinc on the reduction of frost damage in newly grafted seedlings under outdoor conditions. Materials and methods: This research was conducted at agricultural research station, Khoy city, west Azerbaijan province, during 2012-2014. In the first experiment, three methods of grafting including cleft, bark and V-shaped, and two kinds of graft covers including moist sawdust and superabsorbent plus cotton wool were investigated in terms of grafting success and quality of seedlings. In the second experiment, effect of the three above-mentioned grafting methods and two levels of foliar spray including sequential spray of Ca (4 ppm, B and Zn (2% (3 times during growth season and control (no spray were studied in terms of frost damage. The experiments conducted in factorial based on randomized complete block design with 10 trees in each plot. Data were collected 45 days after grafting take, final grafting take after one winter, subsequent scion growth length and diameter and concentration of Ca, B and Zn in

Suction blister grafting - Modifications for easy harvesting and grafting

Directory of Open Access Journals (Sweden)

2012-01-01

Full Text Available Suction blister grafting is a simple modality of treatment of patients with resistant and stable vitiligo. But raising the blisters may be time consuming and transferring to the recipient site may be difficult as the graft is ultrathin. By doing some modifications we can make the technique simpler and easier. We can decrease the blister induction time by intradermal injection of saline, exposure to Wood′s lamp, intrablister injection of saline. By these methods we can decrease the blister induction time from 2-3 hrs to 45-90 minutes. After harvesting the graft, it can be transferred to the recipient area by taking the graft on a sterile glass slide, on the gloved finger, rolling the graft over a sterile syringe and then spreading on the recipient area, or taking on the sterile wrapper of paraffin dressing and then placing over the recipient area.

Evaluation of synthetic vascular grafts in a mouse carotid grafting model.

Science.gov (United States)

Chan, Alex H P; Tan, Richard P; Michael, Praveesuda L; Lee, Bob S L; Vanags, Laura Z; Ng, Martin K C; Bursill, Christina A; Wise, Steven G

2017-01-01

Current animal models for the evaluation of synthetic grafts are lacking many of the molecular tools and transgenic studies available to other branches of biology. A mouse model of vascular grafting would allow for the study of molecular mechanisms of graft failure, including in the context of clinically relevant disease states. In this study, we comprehensively characterise a sutureless grafting model which facilitates the evaluation of synthetic grafts in the mouse carotid artery. Using conduits electrospun from polycaprolactone (PCL) we show the gradual development of a significant neointima within 28 days, found to be greatest at the anastomoses. Histological analysis showed temporal increases in smooth muscle cell and collagen content within the neointima, demonstrating its maturation. Endothelialisation of the PCL grafts, assessed by scanning electron microscopy (SEM) analysis and CD31 staining, was near complete within 28 days, together replicating two critical aspects of graft performance. To further demonstrate the potential of this mouse model, we used longitudinal non-invasive tracking of bone-marrow mononuclear cells from a transgenic mouse strain with a dual reporter construct encoding both luciferase and green fluorescent protein (GFP). This enabled characterisation of mononuclear cell homing and engraftment to PCL using bioluminescence imaging and histological staining over time (7, 14 and 28 days). We observed peak luminescence at 7 days post-graft implantation that persisted until sacrifice at 28 days. Collectively, we have established and characterised a high-throughput model of grafting that allows for the evaluation of key clinical drivers of graft performance.

Evaluation of synthetic vascular grafts in a mouse carotid grafting model.

Directory of Open Access Journals (Sweden)

Alex H P Chan

Full Text Available Current animal models for the evaluation of synthetic grafts are lacking many of the molecular tools and transgenic studies available to other branches of biology. A mouse model of vascular grafting would allow for the study of molecular mechanisms of graft failure, including in the context of clinically relevant disease states. In this study, we comprehensively characterise a sutureless grafting model which facilitates the evaluation of synthetic grafts in the mouse carotid artery. Using conduits electrospun from polycaprolactone (PCL we show the gradual development of a significant neointima within 28 days, found to be greatest at the anastomoses. Histological analysis showed temporal increases in smooth muscle cell and collagen content within the neointima, demonstrating its maturation. Endothelialisation of the PCL grafts, assessed by scanning electron microscopy (SEM analysis and CD31 staining, was near complete within 28 days, together replicating two critical aspects of graft performance. To further demonstrate the potential of this mouse model, we used longitudinal non-invasive tracking of bone-marrow mononuclear cells from a transgenic mouse strain with a dual reporter construct encoding both luciferase and green fluorescent protein (GFP. This enabled characterisation of mononuclear cell homing and engraftment to PCL using bioluminescence imaging and histological staining over time (7, 14 and 28 days. We observed peak luminescence at 7 days post-graft implantation that persisted until sacrifice at 28 days. Collectively, we have established and characterised a high-throughput model of grafting that allows for the evaluation of key clinical drivers of graft performance.

Delayed grafting for banked skin graft in lymph node flap transfer.

Science.gov (United States)

Ciudad, Pedro; Date, Shivprasad; Orfaniotis, Georgios; Dower, Rory; Nicoli, Fabio; Maruccia, Michele; Lin, Shu-Ping; Chuang, Chu-Yi; Chuang, Tsan-Yu; Wang, Gou-Jen; Chen, Hung-Chi

2017-02-01

Over the last decade, lymph node flap (LNF) transfer has turned out to be an effective method in the management of lymphoedema of extremities. Most of the time, the pockets created for LNF cannot be closed primarily and need to be resurfaced with split thickness skin grafts. Partial graft loss was frequently noted in these cases. The need to prevent graft loss on these iatrogenic wounds made us explore the possibility of attempting delayed skin grafting. We have herein reported our experience with delayed grafting with autologous banked split skin grafts in cases of LNF transfer for lymphoedema of the extremities. Ten patients with International Society of Lymphology stage II-III lymphoedema of upper or lower extremity were included in this study over an 8-month period. All patients were thoroughly evaluated and subjected to lymph node flap transfer. The split skin graft was harvested and banked at the donor site, avoiding immediate resurfacing over the flap. The same was carried out in an aseptic manner as a bedside procedure after confirming flap viability and allowing flap swelling to subside. Patients were followed up to evaluate long-term outcomes. Flap survival was 100%. Successful delayed skin grafting was done between the 4th and 6th post-operative day as a bedside procedure under local anaesthesia. The split thickness skin grafts (STSG) takes more than 97%. One patient needed additional medications during the bedside procedure. All patients had minimal post-operative pain and skin graft requirement. The patients were also reported to be satisfied with the final aesthetic results. There were no complications related to either the skin grafts or donor sites during the entire period of follow-up. Delayed split skin grafting is a reliable method of resurfacing lymph node flaps and has been shown to reduce the possibility of flap complications as well as the operative time and costs. © 2016 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

Skin Graft

OpenAIRE

Shimizu, Ruka; Kishi, Kazuo

2012-01-01

Skin graft is one of the most indispensable techniques in plastic surgery and dermatology. Skin grafts are used in a variety of clinical situations, such as traumatic wounds, defects after oncologic resection, burn reconstruction, scar contracture release, congenital skin deficiencies, hair restoration, vitiligo, and nipple-areola reconstruction. Skin grafts are generally avoided in the management of more complex wounds. Conditions with deep spaces and exposed bones normally require the use o...

Preparation of polymer electrolyte membranes for lithium batteries by radiation-induced graft copolymerization

Energy Technology Data Exchange (ETDEWEB)

Nasef, Mohamed Mahmoud [Business and Advanced Technology Centre, Universiti Teknologi Malaysia, Jalan Semarak, 54100 Kuala Lumpur (Malaysia); Suppiah, Raja Rajeswary [Chemical Engineering Program, Universiti Teknologi Petronas, Bandar Seri Iskandar, 37150 Tronoh, Perak (Malaysia); Dahlan, Khairul Zaman Mohd [Malaysian Institute for Nuclear Technology Research, Bangi, 43000 Kajang (Malaysia)

2004-07-30

Polymer electrolyte membranes with different degrees of grafting were prepared by radiation-induced graft copolymerization of styrene monomer onto poly(vinylidene fluoride) (PVDF) films and subsequent chemical activation with liquid electrolyte consisting of lithium hexafluorophosphate (LiPF{sub 6}) in a mixture of ethylene carbonate/diethylene carbonate (EC/DEC). The chemical changes in the PVDF films after styrene grafting and subsequent chemical activation were monitored by FTIR spectroscopic analysis and the crystallinity was evaluated using differential scanning calorimetric (DSC) analysis. The swelling in electrolyte solution (electrolyte uptake) and the ionic conductivity of the membranes were determined at various degrees of grafting. The conductivity of the membranes was found to increase with the increase in the degree of grafting and reached a magnitude of 10{sup -3} S/cm at a degree of grafting of 50%. The results of this work suggest that radiation-induced graft polymerization provides an alternative method to substitute blending in preparation of polymer electrolyte membranes for application in lithium batteries.

Evaluation of Replacement Grafts and Punch Grafts in the Treatment of Vitiligo

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Singh Ajit Kumar

1980-01-01

Full Text Available Thirtycasesof vitiligo eachwithminimum of two lesions undent replacement graft and multiple punch grafts in one lesion each. Complications observed at the recipient site like infection and raised nigosed surface were significantly more in replacement grafts. Hypopigmentation of the graft was significantly more when the disease was progressive.

Chrysanthemum cutting productivity and rooting ability are improved by grafting.

Science.gov (United States)

Zhang, Jing; Chen, Sumei; Liu, Ruixia; Jiang, Jiafu; Chen, Fadi; Fang, Weimin

2013-01-01

Chrysanthemum has been commercially propagated by rooting of cuttings, whereas the quality will decline over multiple collections from a single plant. Therefore, we compared the vigour, rooting ability, and some physiological parameters between cuttings harvested from nongrafted "Jinba" (non-grafted cuttings) with those collected from grafted "Jinba" plants onto Artemisia scoparia as a rootstock (grafted cuttings). The yield, length, node number, stem diameter, fresh weight, and dry weight of the grafted cuttings were superior to the non-grafted cuttings. Also grafted cuttings "Jinba" rooted 1 day earlier, but showing enhanced rooting quality including number, length, diameter, and dry weight of roots, where compared to the non-grafted. The physiological parameters that indicated contents of soluble protein, peroxidase activity, soluble sugar, and starch, ratios of soluble sugar/nitrogen ratio, and carbohydrate/nitrogen (C/N), as well as contents of indole-3-acetic acid (IAA) and abscisic acid (ABA), and IAA/ABA ratio were significantly increased in the grafted cuttings. This suggested their important parts in mediating rooting ability. Results from this study showed that grafting improved productivity and rooting ability related to an altered physiology, which provide a means to meet the increasing demand.

Platelet-rich plasma-enriched autologous fat graft in regenerative and aesthetic facial surgery: Technical note.

Science.gov (United States)

Picard, F; Hersant, B; La Padula, S; Meningaud, J-P

2017-09-01

The goal of adding platelet-rich plasma (PRP) to autologous fat graft is to increase the survival rate of the graft. After their activation, platelets release some important growth factors. As a result, PRP may increase the proliferation and differentiation of Adipose-derived stem cells (ASCs) into adipocytes, improve fat graft vascularisation, and may block the apoptosis of grafted adipocytes. The other benefit expected from the addition of PRP to fat graft is the improvement of cutaneous trophicity above the grafted areas. An exhaustive review of the literature retrieved 11 clinical studies on humans and 7 on animals. A statistically significant increase of the survival rate of fat grafts has been found in 9 comparative studies. Our synthesis allowed us to set up the following protocol: addition of 20% of PRP activated with calcium hydrochloride to fat grafts. It may enhance the results of autologous facial fat graft in regenerative and aesthetic facial surgery. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Comparative Proteomic Analysis of the Graft Unions in Hickory (Carya cathayensis Provides Insights into Response Mechanisms to Grafting Process

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Daoliang Yan

2017-04-01

Full Text Available Hickory (Carya cathayensis, a tree with high nutritional and economic value, is widely cultivated in China. Grafting greatly reduces the juvenile phase length and makes the large scale cultivation of hickory possible. To reveal the response mechanisms of this species to grafting, we employed a proteomics-based approach to identify differentially expressed proteins in the graft unions during the grafting process. Our study identified 3723 proteins, of which 2518 were quantified. A total of 710 differentially expressed proteins (DEPs were quantified and these were involved in various molecular functional and biological processes. Among these DEPs, 341 were up-regulated and 369 were down-regulated at 7 days after grafting compared with the control. Four auxin-related proteins were down-regulated, which was in agreement with the transcription levels of their encoding genes. The Kyoto Encyclopedia of Genes and Genomes (KEGG analysis showed that the ‘Flavonoid biosynthesis’ pathway and ‘starch and sucrose metabolism’ were both significantly up-regulated. Interestingly, five flavonoid biosynthesis-related proteins, a flavanone 3-hyfroxylase, a cinnamate 4-hydroxylase, a dihydroflavonol-4-reductase, a chalcone synthase, and a chalcone isomerase, were significantly up-regulated. Further experiments verified a significant increase in the total flavonoid contents in scions, which suggests that graft union formation may activate flavonoid biosynthesis to increase the content of a series of downstream secondary metabolites. This comprehensive analysis provides fundamental information on the candidate proteins and secondary metabolism pathways involved in the grafting process for hickory.

Feasibility of the Use of RapiGraft and Skin Grafting in Reconstructive Surgery

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Jung Dug Yang

2016-09-01

Full Text Available BackgroundSkin grafting is a relatively simple and thus widely used procedure. However, the elastic and structural quality of grafted skin is poor. Recently, various dermal substitutes have been developed to overcome this disadvantage of split-thickness skin grafts. The present study aims to determine the feasibility of RapiGraft as a new dermal substitute.MethodsThis prospective study included 20 patients with partial- or full-thickness skin defects; the patients were enrolled between January 2013 and March 2014. After skin defect debridement, the wound was divided into two parts by an imaginary line. Split-thickness skin grafting alone was performed on one side (group A, and RapiGraft and split-thickness skin grafting were used on the other side (group B. All patients were evaluated using photographs and self-questionnaires. The Manchester scar scale (MSS, a chromameter, and a durometer were used for the scar evaluation. The average follow-up period was 6 months.ResultsThe skin graft take rates were 93% in group A and 89% in group B, a non-significant difference (P=0.082. Statistically, group B had significantly lower MSS, vascularity, and pigmentation results than group A (P<0.05 for all. However, the groups did not differ significantly in pliability (P=0.155.ConclusionsThe present study indicates that a simultaneous application of RapiGraft and a split-thickness skin graft is safe and yields improved results. Therefore, we conclude that the use of RapiGraft along with skin grafting will be beneficial for patients requiring reconstructive surgery.

Influence of temperature on radiation-induced graft polymerization of styrene onto poly(ethylene terephthalate) nuclear membranes and films

International Nuclear Information System (INIS)

Zhitaryuk, N.I.; Shtan'ko, N.I.

1989-01-01

Temperature effect on kinetics of radiation-induced graft polymerization of styrene onto poly(ethylene terephthalate) (PETP) nuclear membranes with various parameters (pore diameter, the average distance between the pores) as well as onto PETP films with different thickness has been studied. Graft polymerization has been carried out by the methods of preirradiation in air and in vacuum. The overall activation energy of grafting as well as the activation energy of swelling of PETP in toluene has been obtained. It was found that in the method of preirradiation in vacuum the initial grafting rate in Arrhenius plot has two linear ranges. Activation energy in low temperature range correlates with activation energy of PETP swelling. Activation energy in high temperature range is determined by kinetics of graft polymerization in the method of preirradiation in air. Arrhenius plot of the initial grafting rate gives the activation energy that approximately corresponds to the initiation of grafting with oxyradicals. Dependence of PETP matrix critical thickness on temperature has also been obtained. The form of this dependence is identical to the one of the rate of graft polymerization. 33 refs.; 6 figs.; 2 tabs

Cartilage grafting in facial reconstruction with special consideration of irradiated grafts

International Nuclear Information System (INIS)

Donald, P.J.

1986-01-01

The search for the perfect facial implant for reconstruction of the face continues. Cartilage, once thought to be an undesirable graft material because of its propensity for absorption, has regained popularity in the past decade. Various preparation techniques have been employed to ensure graft sterility and diminished absorption. An improved understanding of cartilage structure and physiology has shed considerable light on the host-graft relationship. Gamma irradiation is a time-honored method of preservation. An experiment was undertaken to investigate the physiology of irradiated cartilage grafts following prolonged implantation on the facial skeleton of sheep and dog. Merthiolate preserved grafts were used as controls. Direct observation, histochemical techniques, autoradiography, and transmission electron micrography were used to determine chondrocyte viability and matrix composition. It was surprising to note that following implantation of 16 to 72 months, complete resorption was seen in 87.7% of the irradiated grafts and in 43.8% of the Merthiolate stored controls. Many of the grafts acquired chondrocytes from the host and produced new proteoglycan matrix as well as undergoing some degree of ossification. A comparison to the clinical situation in humans is made. 98 references

Modeling conduction in host-graft interactions between stem cell grafts and cardiomyocytes.

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Chen, Michael Q; Yu, Jin; Whittington, R Hollis; Wu, Joseph C; Kovacs, Gregory T A; Giovangrandi, Laurent

2009-01-01

Cell therapy has recently made great strides towards aiding heart failure. However, while transplanted cells may electromechanically integrate into host tissue, there may not be a uniform propagation of a depolarization wave between the heterogeneous tissue boundaries. A model using microelectrode array technology that maps the electrical interactions between host and graft tissues in co-culture is presented and sheds light on the effects of having a mismatch of conduction properties at the boundary. Skeletal myoblasts co-cultured with cardiomyocytes demonstrated that conduction velocity significantly decreases at the boundary despite electromechanical coupling. In an attempt to improve the uniformity of conduction with host cells, differentiating human embryonic stem cells (hESC) were used in co-culture. Over the course of four to seven days, synchronous electrical activity was observed at the hESC boundary, implying differentiation and integration. Activity did not extend far past the boundary, and conduction velocity was significantly greater than that of the host tissue, implying the need for other external measures to properly match the conduction properties between host and graft tissue.

Radioinduced grafting of acrylic acid on expanded polystyrene matrices

International Nuclear Information System (INIS)

Postolache, C.; Simion, Corina; Dragomir, A.; Ponta, C.; Chirvasoiu, G.; Postolache, Carmen

1998-01-01

The unfixed surface radioactive contamination for low energy β radionuclides ( 3 H and 14 C) is determined by wiping the checked surfaces with sponge of absorbent materials. The activity built up by this sponge is measured by a liquid scintillator spectrometer. In this work, a method of obtaining sponges of expanded polystyrene with hydrophobic surface by radioinduced grafting of the acrylic acid is presented. These sponges have diameters of 28 mm, thicknesses of 1.5 - 2 mm and density of 22 mg/cm 3 . The samples were immersed in a grafting solution with the following composition: acrylic acid 30%, Cu SO 4 1%; water 69% which were deeply impregnated in repeated operations under vacuum and pressure conditions, respectively. Finally, the samples were exposed to γ radiation emitted by a 60 Co source (IETI 10 000 - IFIN-HH). The dose rates were 0.3, 0.5 and 1 Mrad/h. The range of the absorbed doses was 1 - 25 Mrad. The yields of radiochemical grafting have been determined by gravimetric, spectrophotometric and radiometric methods. The grafting agent used was 3 H labelled acrylic acid. The solvation capacity and the quenching characteristics of the grafted sponges in liquid scintillators, as well as the sampling yields have been analyzed as function of irradiation procedure and the percentage of grafted acrylic fragments. The superficial grafting of the acrylic acid has been carried out by the mentioned technique, leading to the increase of the wiping efficiency of the unfixed surface contaminating activity, without changes of polymer solubility in liquid scintillators and without the perturbation of the radioactivity detection process. (authors)

Plasma-grafting polymerization on carbon fibers and its effect on their composite properties

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Zhang, Huanxia; Li, Wei

2015-11-01

Interfacial adhesion between matrix and fibers plays a crucial role in controlling the performance of composites. Carbon fibers have the major constraint of chemical interness and hence have limited adhesion with the matrix. Surface treatment of fibers is the best solution to this problem. In this work, carbon fibers were activated by plasma and grafting polymerization. The grafting ratio of polymerization was obtained by acid-base titration. The chemical and physical changes induced by the treatments on carbon fiber surface was examined using contact angle measurements, X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) technique. The interfacial adhesion of CF/EP (carbon fiber/epoxy) composites were analyzed by a single fiber composite (SFC) for filament fragmentation test. Experimental results show that the grafting rate was not only the function of the plasma-treat time but also the concentration of the grafting polymerization. The oxygen-containing groups (such as Csbnd O, Cdbnd O, and Osbnd Cdbnd O) and the interfacial shear strength (IFSS) of the plasma-grafting carbon fiber increased more significantly than the carbon fiber without plasma treatment grafted with MAH. This demonstrates that the surfaces of the carbon fiber samples are more active, hydrophilic, and rough after plasma-grafting treatments using a DBD operating in ambient argon mixture with oxygen. With DBD (dielectric barrier discharges) operating in ambient argon mixture with oxygen, the more active, hydrophilic, and rough surface was obtained by the plasma-grafting treatments.

Kidney graft rejection studies with labeled platelets and lymphocytes

International Nuclear Information System (INIS)

Martin-Comin, J.

1986-01-01

The usefulness of In-111-labelled platelets and lymphocyte scintigraphy in acute kidney graft rejection is evaluated in 155 patients. Blood cells were labelled with 100-150 uCi of In-111-oxine and reinjected. Subsequently patients were scanned once daily from 2 hours post-reinjection up to a week. The graft/contralateral area activity ratio was calculated in all scans. It is concluded that In-111-labelled platelets scintigraphy is nowadays the method of choice for acute kidney graft rejection diagnosis, especially in patients under cyclosporine immunosuppression. (author)

Grafting of gold nanoparticles on polyethyleneterephthalate using dithiol interlayer

International Nuclear Information System (INIS)

Reznickova, A.; Kolska, Z.; Zaruba, K.; Svorcik, V.

2014-01-01

Two different procedures of grafting of polyethyleneterephthalate (PET), modified by plasma treatment, with gold nanoparticles (nanospheres) are studied. In the first procedure the PET foil was grafted with biphenyl-4,4′-dithiol and subsequently with gold nanoparticles. In the second one the PET foil was grafted with gold nanoparticles previously coated by the same dithiol. X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and electrokinetic analysis were used for characterization of the polymer surface at different modification steps. Gold nanoparticles were characterized by ultraviolet–visible spectroscopy. The first procedure was found to be more effective. It was proved that the dithiol was chemically bonded to the surface of the plasma activated PET and it mediates subsequent grafting of the gold nanoparticles. - Highlights: • Two different techniques were used for coating of PET with gold nanoparticles. • Grafted GNPs were characterized by XPS, FTIR, UV–vis, zeta potential, AFM. • More effective coating is achieved by deposition of GNPs earlier grafted with thiol. • The studied structures may have potential application in electronics or biomedicine

Evaluation of early coronary graft patency after coronary artery bypass graft surgery using multislice computed tomography angiography

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Raissi Kamal

2009-12-01

Full Text Available Abstract Background Coronary artery bypass graft (CABG surgery is the standard of care in the treatment of advanced coronary artery disease, and its long-term results are affected by the failure of bypass grafts. The aim of the present study was to evaluate the early patency rate in coronary bypass grafts. Methods A total of 107 consecutive patients who underwent CABG were included in this study. Early graft patency was evaluated via computed tomography (CT angiography in the first week after surgery. Results There were a total of 366 grafts, comprised of 250 venous grafts and 116 arterial grafts. Multi-slice CT detected acute graft occlusions in 32 (8.7% of all the grafts, including 26 (10% of the 250 venous grafts and 6 (5% of the 116 arterial grafts. The patency rates obtained were 97.3% for the left internal mammary (IMA grafts, 50% for the radial artery grafts, and 50% for the right IMA grafts. Additionally, 107 (96.4% grafts to the left anterior descending artery (LAD were classified as patent, whereas 1 (30% of the 3 grafts in the left circumflex (LCX region and 1 (50% of the 2 grafts in the right coronary artery (RCA territory were found to be occluded. In the venous category, 8 (13.7% of the 58 grafts to LAD were found to be occluded. In the LCX region, 9 (8.5% of the 106 grafts were classified as occluded, while the remaining 97 (91.5% grafts were patent. The venous grafts to RCA were occluded in 9 (10.4% of the 86 grafts. Amongst the multiple preoperative, intraoperative, and postoperative factors, pump time was significantly longer in the patients with occluded grafts than in those with patent grafts (P = 0.04. Conclusion The IMA grafts had the highest early patency rate amongst the coronary bypass grafts. However, the other arterial grafts were associated with a high rate of acute occlusions.

Enhanced binding by dextran-grafting to Protein A affinity chromatographic media.

Science.gov (United States)

Zhao, Lan; Zhu, Kai; Huang, Yongdong; Li, Qiang; Li, Xiunan; Zhang, Rongyue; Su, Zhiguo; Wang, Qibao; Ma, Guanghui

2017-04-01

Dextran-grafted Protein A affinity chromatographic medium was prepared by grafting dextran to agarose-based matrix, followed by epoxy-activation and Protein A coupling site-directed to sulfhydryl groups of cysteine molecules. An enhancement of both the binding performance and the stability was achieved for this dextran-grafted Protein A chromatographic medium. Its dynamic binding capacity was 61 mg immunoglobulin G/mL suction-dried gel, increased by 24% compared with that of the non-grafted medium. The binding capacity of dextran-grafted medium decreased about 7% after 40 cleaning-in-place cycles, much lower than that of the non-grafted medium as decreased about 15%. Confocal laser scanning microscopy results showed that immunoglobulin G was bound to both the outside and the inside of dextran-grafted medium faster than that of non-grafted one. Atomic force microscopy showed that this dextran-grafted Protein A medium had much rougher surface with a vertical coordinate range of ±80 nm, while that of non-grafted one was ±10 nm. Grafted dextran provided a more stereo surface morphology and immunoglobulin G molecules were more easily to be bound. This high-performance dextran-grafted Protein A affinity chromatographic medium has promising applications in large-scale antibody purification. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Plasma-grafting polymerization on carbon fibers and its effect on their composite properties

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Zhang, Huanxia, E-mail: zhanghuanxia818@163.com [College of Materials and Textile Engineering, Jiaxing University, Jiaxing 314001, Zhejiang (China); Li, Wei [College of Textile Engineering, Donghua University, Shanghai 201620 (China); Key Laboratory of Textile Science and Technology, Ministry of Education, Shanghai 201620 (China)

2015-11-30

Graphical abstract: - Highlights: • A simple method to improve surface properties is applied to carbon fibers. • The maleic anhydride was grafted onto the carbon fiber with the FTIR spectra. • The plasma treatment time and polymerization condition affected on the grafting rate. • The carbon fibers exhibited excellent surface hydrophilicity and IFSS properties. - Abstract: Interfacial adhesion between matrix and fibers plays a crucial role in controlling the performance of composites. Carbon fibers have the major constraint of chemical interness and hence have limited adhesion with the matrix. Surface treatment of fibers is the best solution to this problem. In this work, carbon fibers were activated by plasma and grafting polymerization. The grafting ratio of polymerization was obtained by acid–base titration. The chemical and physical changes induced by the treatments on carbon fiber surface was examined using contact angle measurements, X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy-attenuated total reflectance (FTIR–ATR) technique. The interfacial adhesion of CF/EP (carbon fiber/epoxy) composites were analyzed by a single fiber composite (SFC) for filament fragmentation test. Experimental results show that the grafting rate was not only the function of the plasma-treat time but also the concentration of the grafting polymerization. The oxygen-containing groups (such as C−O, C=O, and O−C=O) and the interfacial shear strength (IFSS) of the plasma-grafting carbon fiber increased more significantly than the carbon fiber without plasma treatment grafted with MAH. This demonstrates that the surfaces of the carbon fiber samples are more active, hydrophilic, and rough after plasma-grafting treatments using a DBD operating in ambient argon mixture with oxygen. With DBD (dielectric barrier discharges) operating in ambient argon mixture with oxygen, the more active, hydrophilic, and rough surface was obtained by the

Plasma-grafting polymerization on carbon fibers and its effect on their composite properties

International Nuclear Information System (INIS)

Zhang, Huanxia; Li, Wei

2015-01-01

Graphical abstract: - Highlights: • A simple method to improve surface properties is applied to carbon fibers. • The maleic anhydride was grafted onto the carbon fiber with the FTIR spectra. • The plasma treatment time and polymerization condition affected on the grafting rate. • The carbon fibers exhibited excellent surface hydrophilicity and IFSS properties. - Abstract: Interfacial adhesion between matrix and fibers plays a crucial role in controlling the performance of composites. Carbon fibers have the major constraint of chemical interness and hence have limited adhesion with the matrix. Surface treatment of fibers is the best solution to this problem. In this work, carbon fibers were activated by plasma and grafting polymerization. The grafting ratio of polymerization was obtained by acid–base titration. The chemical and physical changes induced by the treatments on carbon fiber surface was examined using contact angle measurements, X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy-attenuated total reflectance (FTIR–ATR) technique. The interfacial adhesion of CF/EP (carbon fiber/epoxy) composites were analyzed by a single fiber composite (SFC) for filament fragmentation test. Experimental results show that the grafting rate was not only the function of the plasma-treat time but also the concentration of the grafting polymerization. The oxygen-containing groups (such as C−O, C=O, and O−C=O) and the interfacial shear strength (IFSS) of the plasma-grafting carbon fiber increased more significantly than the carbon fiber without plasma treatment grafted with MAH. This demonstrates that the surfaces of the carbon fiber samples are more active, hydrophilic, and rough after plasma-grafting treatments using a DBD operating in ambient argon mixture with oxygen. With DBD (dielectric barrier discharges) operating in ambient argon mixture with oxygen, the more active, hydrophilic, and rough surface was obtained by the

Pancreas grafts

International Nuclear Information System (INIS)

Hahn, D.; Buell, U.; Land, W.; Unertl, K.

1981-01-01

Perfusion studies with sup(99m)Tc-DTPA, which has hitherto been used routinely to investigate renal grafts, have also proved useful for monitoring the perfusion of pancreas grafts. A total perfusion failure is equally reliably demonstrable as in renal grafts. Quantitatively smaller perfusion alterations can be demonstrated by monitoring the course. It seems possible to differentiate the salivary edema of a rejection reaction, well known from animal experiments, with the help of other paramters (e.g. creatinine). Further clinical studies are however necessary to confirm these results. (orig.) [de

Graft union formation in artichoke grafting onto wild and cultivated cardoon: an anatomical study.

Science.gov (United States)

Trinchera, Alessandra; Pandozy, Gianmarco; Rinaldi, Simona; Crinò, Paola; Temperini, Olindo; Rea, Elvira

2013-12-15

In order to develop a non-chemical method such as grafting effective against well-known artichoke soil borne diseases, an anatomical study of union formation in artichoke grafted onto selected wild and cultivated cardoon rootstocks, both resistant to Verticillium wilt, was performed. The cardoon accessions Belgio (cultivated cardoon) and Sardo (wild cardoon) were selected as rootstocks for grafting combinations with the artichoke cv. Romolo. Grafting experiments were carried out in the autumn and spring. The anatomical investigation of grafting union formation was conducted by scanning electron microscopy (SEM) on the grafting portions at the 3rd, 6th, 10th, 12th day after grafting. For the autumn experiment only, SEM analysis was also performed at 30 d after grafting. A high affinity between artichoke scion and cardoon rootstocks was observed, with some genotype differences in healing time between the two bionts. SEM images of scion/rootstock longitudinal sections revealed the appearance of many interconnecting structures between the two grafting components just 3d after grafting, followed by a vascular rearrangement and a callus development during graft union formation. De novo formation of many plasmodesmata between scion and rootstock confirmed their high compatibility, particularly in the globe artichoke/wild cardoon combination. Moreover, the duration of the early-stage grafting process could be influenced not only by the scion/rootstock compatibility, but also by the seasonal conditions, being favored by lower temperatures and a reduced light/dark photoperiod. Copyright © 2013 Elsevier GmbH. All rights reserved.

Respiratory muscle stretch gymnastics in patients with post coronary artery bypass grafting pain : Impact on respiratory muscle function, activity, mood and exercise capacity

OpenAIRE

會田, 信子; 渋谷, 優子; 吉野, 克樹; Komoda, Masaji; 井上, 智子

2002-01-01

A new rehabilitation (New-RH) program including respiratory muscle stretch gymnastics (RMSG) was developed to alleviate post-coronary artery bypass grafting pain (PCP). Effects on respiratory muscle function, pain, activities of daily living (ADL), mood and exercise capacity were investigated. Subjects were 16 consecutive patients undergoing median full sternotomy coronary artery bypass grafting (CABG), and were randomly divided into equal New-RH (S-group) and conventional therapy (C-group) g...

A COMPARATIVE STUDY OF TYMPANOPLASTY USING SLICED CARTILAGE GRAFT VS. TEMPORALIS FASCIA GRAFT

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Rahul Ashok Telang

2018-02-01

Full Text Available BACKGROUND The objective of the study was to compare the hearing improvement after using sliced cartilage graft with that of temporalis fascia and to compare the graft take-up between the two graft materials. MATERIALS AND METHODS A prospective clinical study including 60 patients with chronic mucosal otitis media, who were selected randomly from the outpatient department, after obtaining their consent were divided into 2 groups of 30 each, and evaluated according the study protocol. Their pre-operative audiometry was recorded and both groups of patients underwent surgery with one of the graft materials- temporalis fascia or sliced tragal cartilage with a thickness of 0.5 mm. All patients were regularly followed up and post-operative audiometry was done at 3 months. The hearing improvement in the form of closure of air-bone-gap and graft take-up was analysed statistically. RESULTS The temporalis fascia graft group had a pre-operative ABG of 22.33 ± 6.24 dB and post-operative ABG of 12.33 ± 4.72 dB with hearing improvement of 10.00 dB. The sliced cartilage graft group had a pre-operative ABG of 20.77 ± 5.75 dB and postoperative ABG of 10.50 ± 4.46 dB with hearing improvement of 10.27 dB. In the temporalis fascia group, 28 (93.3% patients had good graft take-up and in the sliced cartilage group 29 (96.7% had good graft take-up. There was statistically significant hearing improvement in both of our study groups but there was no statistically significant difference between the two groups. There was no statistically significant difference in graft take-up also. CONCLUSION Sliced cartilage graft is a good auto-graft material in tympanoplasty, which can give good hearing improvement and has good graft take-up, which is comparable with that of temporalis fascia.

In vivo evaluation of wound bed reaction and graft performance after cold skin graft storage: new targets for skin tissue engineering.

Science.gov (United States)

Knapik, Alicia; Kornmann, Kai; Kerl, Katrin; Calcagni, Maurizio; Schmidt, Christian A; Vollmar, Brigitte; Giovanoli, Pietro; Lindenblatt, Nicole

2014-01-01

Surplus harvested skin grafts are routinely stored at 4 to 6°C in saline for several days in plastic surgery. The purpose of this study was to evaluate the influence of storage on human skin graft performance in an in vivo intravital microscopic setting after transplantation. Freshly harvested human full-thickness skin grafts and split-thickness skin grafts (STSGs) after storage of 0, 3, or 7 days in moist saline at 4 to 6°C were transplanted into the modified dorsal skinfold chamber, and intravital microscopy was performed to evaluate vessel morphology and angiogenic change of the wound bed. The chamber tissue was harvested 10 days after transplantation for evaluation of tissue integrity and inflammation (hematoxylin and eosin) as well as for immunohistochemistry (human CD31, murine CD31, Ki67, Tdt-mediated dUTP-biotin nick-end labelling). Intravital microscopy results showed no differences in the host angiogenic response between fresh and preserved grafts. However, STSGs and full-thickness skin grafts exhibited a trend toward different timing and strength in capillary widening and capillary bud formation. Preservation had no influence on graft quality before transplantation, but fresh STSGs showed better quality 10 days after transplantation than 7-day preserved grafts. Proliferation and apoptosis as well as host capillary in-growth and graft capillary degeneration were equal in all groups. These results indicate that cells may activate protective mechanisms under cold conditions, allowing them to maintain function and morphology. However, rewarming may disclose underlying tissue damage. These findings could be translated to a new approach for the design of full-thickness skin substitutes.

Outcomes of AV Fistulas and AV Grafts after Interventional Stent-Graft Deployment in Haemodialysis Patients

Energy Technology Data Exchange (ETDEWEB)

Schmelter, Christopher, E-mail: christopher.schmelter@klinikum-ingolstadt.de; Raab, Udo, E-mail: udo.raab@klinikum-ingolstadt.de [Klinikum Ingolstadt, Department of Diagnostic and Interventional Radiology (Germany); Lazarus, Friedrich, E-mail: friedrich.lazarus@klinikum-ingolstadt.de [Klinikum Ingolstadt, Department of Nephrology (Germany); Ruppert, Volker, E-mail: volker.ruppert@klinikum-ingolstadt.de [Klinikum Ingolstadt, Department of Vascular Surgery (Germany); Vorwerk, Dierk, E-mail: dierk.vorwerk@klinikum-ingolstadt.de [Klinikum Ingolstadt, Department of Diagnostic and Interventional Radiology (Germany)

2015-08-15

PurposeThe study was designed to assess outcomes of arteriovenous (AV) accesses after interventional stent-graft deployment in haemodialysis patients.Materials and Methods63 haemodialysis patients with 66 AV fistulas and AV grafts were treated by interventional stent-graft deployment from 2006 to 2012 at our hospital. Data of these patients were retrospectively analysed for location of deployed stent-grafts, occurrence and location of (re-)stenosis and (re-)thrombosis. Complex stenosis was the most frequent indication for stent-graft deployment (45.5 %), followed by complications of angioplasty with vessel rupture or dissection (31.8 %).ResultsA high rate of procedural success was achieved (98.5 %). The most frequent location of the deployed stent-graft was the draining vein (66.7 %). Stent-graft deployment was more frequent in AV grafts than in AV fistulas. Primary patency was 45.5 % at 6 month, 31.3 % at 12 month and 19.2 % at 24 month. Primary patency was significantly better for AV fistulas than for AV grafts with deployed stent-grafts. Patency of the deployed stent-graft was much better than overall AV access primary patency with deployed stent-graft. Re-stenosis with thrombosis was the most frequent indication for re-intervention. Most frequent location of re-stenosis was the draining vein (37.1 %), followed by stenosis at the AV access (29.5 %) and the deployed stent-graft (23.5 %).ConclusionRe-stenosis and re-thrombosis remain frequent in AV fistulas and AV grafts in haemodialysis patients despite stent-graft deployment. Re-stenosis of the deployed stent-graft is, only in the minority of the cases, responsible for AV access dysfunction.

Radiation-grafting of N-vinylimidazole onto silicone rubber for antimicrobial properties

Science.gov (United States)

Meléndez-Ortiz, H. Iván; Alvarez-Lorenzo, Carmen; Burillo, Guillermina; Magariños, Beatriz; Concheiro, Angel; Bucio, Emilio

2015-05-01

Poly(N-vinylimidazole) (PVIm) was grafted numbers onto silicone rubber (SR) with the aim of providing antimicrobial properties. The grafting was carried out by means of gamma rays using the direct method. The influence on the grafting yield of absorbed dose, monomer concentration, addition of FeSO4 salt, composition and type of solvent (H2O, MeOH, THF, and acetone) was investigated. Grafts onto SR between 10% and 90% were obtained at doses from 20 to 100 kGy and a dose rate 10.9 kGy h-1; grafting yield increased with monomer concentration and dose. The new graft copolymers were confirmed by Fourier transform infrared spectroscopy (FT-IR). Differential scanning calorimeter (DSC) showed glass transition at 149 and 159 °C for 38% and 88% grafting respectively. Thermogravimetry analysis (TGA) presented two decomposition temperatures for SR-g-VIm at 380 (PVIm) and 440 °C (SR). SR-g-VIm showed antibacterial activity against Pseudomonas aeruginosa.

Advances in radiation grafting

International Nuclear Information System (INIS)

Hegazy, El-Sayed A.; AbdEl-Rehim, H.A.; Kamal, H.; Kandeel, K.A.

2001-01-01

Graft copolymerization is an attractive means for modifying base polymers because grafting frequently results in the superposition of properties relating to the backbone and pendent chains. Among the various methods for initiating the grafting reaction, ionizing radiation is the cleanest and most versatile method of grafting available. Ion-exchange membranes play an important role in modern technology, especially in separation and purification of materials. The search for improved membrane composition has considered almost every available polymeric material because of its great practical importance. Grafting of polymers with a mixture of monomers is important since different types of chains containing different functional groups are included. A great deal is focused on the waste treatment of heavy and toxic metals from wastewater because of the severe problems of environmental pollution. Functionalized polymers suitable for metal adsorption with their reactive functional groups such as carboxylic and pyridine groups suitable for waste treatment were prepared by radiation grafting method. More reactive chelating groups were further introduced to the grafted copolymer through its functional groups by chemical treatments with suitable reagents. The advances of radiation grafting and possible uses are briefly discussed

Structural and magnetic characterization of copper sulfonated phthalocyanine grafted onto treated polyethylene

Energy Technology Data Exchange (ETDEWEB)

Reznickova, A., E-mail: alena.reznickova@vscht.cz [Department of Solid State Engineering, University of Chemistry and Technology, 166 28, Prague 6 (Czech Republic); Kolska, Z. [Department of Solid State Engineering, University of Chemistry and Technology, 166 28, Prague 6 (Czech Republic); Faculty of Science, J.E. Purkyne University, 400 96 Usti nad Labem (Czech Republic); Orendac, M.; Cizmar, E. [Faculty of Science, P.J. Safarik University, Park Angelinum 9, 04013 Kosice (Slovakia); Sajdl, P. [Department of Power Engineering, University of Chemistry and Technology, 166 28, Prague 6 (Czech Republic); Svorcik, V. [Department of Solid State Engineering, University of Chemistry and Technology, 166 28, Prague 6 (Czech Republic)

2016-08-30

Highlights: • Polyethylene (PE) surface was activated by argon plasma discharge. • Monolayer of copper phthalocyanine was achieved. • ESR proved that CuPc coated PE surface exhibits magnetic properties. • The studied structures may have potential application in spintronics and data storage. - Abstract: This study focuses on high density polyethylene (HDPE) activated by Ar plasma treatment, subsequently grafted with copper sulfonated phthalocyanine (CuPc) especially pointing out to the surface and magnetic properties of those composites. Properties of pristine PE and their plasma treated counterparts were studied by different experimental techniques: X-ray photoelectron spectroscopy (XPS), UV–vis spectroscopy, zeta potential and by electron spin resonance (ESR). XPS analysis confirmed the successful grafting of phthalocyanine. The highest absorption was found for the sample grafted with {sup b}CuPc for 1 h. Electrokinetic analysis also confirmed the plasma treatment and also subsequent CuPc grafting influence significantly the surface chemistry and charge. These results correspond well with XPS determination. ESR studies confirmed the presence of CuPc grafted on HDPE. It was found, that grafting is mediated by magnetically inactive functional groups, rather than radicals. Magnetic properties of CuPc do not seem to change significantly after grafting CuPc on polyethylene surface.

Grafting voltage and pharmacological sensitivity in potassium channels.

Science.gov (United States)

Lan, Xi; Fan, Chunyan; Ji, Wei; Tian, Fuyun; Xu, Tao; Gao, Zhaobing

2016-08-01

A classical voltage-gated ion channel consists of four voltage-sensing domains (VSDs). However, the roles of each VSD in the channels remain elusive. We developed a GVTDT (Graft VSD To Dimeric TASK3 channels that lack endogenous VSDs) strategy to produce voltage-gated channels with a reduced number of VSDs. TASK3 channels exhibit a high host tolerance to VSDs of various voltage-gated ion channels without interfering with the intrinsic properties of the TASK3 selectivity filter. The constructed channels, exemplified by the channels grafted with one or two VSDs from Kv7.1 channels, exhibit classical voltage sensitivity, including voltage-dependent opening and closing. Furthermore, the grafted Kv7.1 VSD transfers the potentiation activity of benzbromarone, an activator that acts on the VSDs of the donor channels, to the constructed channels. Our study indicates that one VSD is sufficient to voltage-dependently gate the pore and provides new insight into the roles of VSDs.

Cytocompatibility of amine functionalized carbon nanoparticles grafted on polyethylene

Energy Technology Data Exchange (ETDEWEB)

Žáková, Pavlína, E-mail: pavlina.zakova@vscht.cz [Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague 6 (Czech Republic); Slepičková Kasálková, Nikola [Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague 6 (Czech Republic); Kolská, Zdeňka [Faculty of Science, J. E. Purkyně University, Ústí nad Labem (Czech Republic); Leitner, Jindřich [Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague 6 (Czech Republic); Karpíšková, Jana; Stibor, Ivan [Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec (Czech Republic); Slepička, Petr; Švorčík, Václav [Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague 6 (Czech Republic)

2016-03-01

Five types of amide–amine Carbon Nano-Particles (CNPs) were prepared by functionalization of CNPs and characterized by several analytical methods. The successful grafting of amines on CNPs was verified by X-ray photoelectron spectroscopy (XPS), organic elemental analysis and electrokinetic analysis. The size and morphology of CNPs were determined from transmission electron microscopy. The surface area and porosity of CNPs were examined by adsorption and desorption isotherms. Differential scanning calorimetry was used to investigate thermal stability of CNPs. The amount of bonded amine depends on its dimensionality arrangement. Surface area and pore volumes of CNPs decrease several times after individual amino-compound grafting. Selected types of functionalized CNPs were grafted onto a plasma activated surface of HDPE. The successful grafting of CNPs on the polymer surface was verified by XPS. Wettability was determined by contact angle measurements. Surface morphology and roughness were studied by atomic force microscopy. A dramatic decrease of contact angle and surface morphology was observed on CNP grafted polymer surface. Cytocompatibility of modified surfaces was studied in vitro, by determination of adhesion, proliferation and viability of vascular smooth muscle cells (VSMCs). Grafting of CNPs onto the polymer surface has a positive effect on the adhesion, proliferation and viability of VSMCs. - Highlights: • Amine functionalized CNPs were successfully grafted on HDPE surface. • Significant change to the positive zeta potential for grafted CNPs was induced. • Grafting of CNPs significantly enhanced cell cytocompatibility and viability. • Homogeneous distribution of cells with correct size was achieved.

Modification of polyetherurethane for biomedical application by radiation-induced grafting. I. Grafting procedure, determination of mechanical properties, and chemical modification of grafted films

International Nuclear Information System (INIS)

Jansen, B.; Ellinghorst, G.

1985-01-01

Radiation grafting of monomers onto suitable trunk polymers is a useful tool for tailoring new polymers for special purposes. This technique has been used in the past for the development of biocompatible materials, e.g., by grafting hydrogels onto mechanically stable polymers. In this first part of our work, the radiation grafting of hydrophilic or reactive monomers onto a polyetherurethane film using the pre-swelling technique is described. Following this technique the trunk polymer was swollen in the monomer before irradiation. As monomers 2-hydroxyethyl methacrylate (HEMA), 2,3-epoxypropyl methacrylate (GMA), 2,3-dihydroxypropyl methacrylate (GOMA), and acrylamide (AAm) were used. The kinetics of the grafting reactions were examined, and the distribution of the graft component inside the trunk polymer was investigated by means of infrared (IR) spectroscopy. Surface-grafted as well as bulk- and surface-grafted products could be obtained. The mechanical behavior of the grafted films--especially in the water-swollen state--was examined and compared with that of the pure trunk polymer. In nearly all cases it was found that the tensile strength sigma B and the elongation at break epsilon R decreases as the grafting yield increases. Modification of GMA- and AAm-grafted films via chemical reactions was performed to create new functional groups of biomedical interest. In this manner a diol structure, a carboxylic acid structure, and a sulfonic acid group could be introduced in the grafted polymer. The water uptake of such modified films is increased markedly when compared with that of the unmodified samples

Functional MRI activation of somatosensory and motor cortices in a hand-grafted patient with early clinical sensorimotor recovery

International Nuclear Information System (INIS)

Neugroschl, C.; Denolin, V.; Schuind, F.; Holder, C. van; David, P.; Baleriaux, D.; Metens, T.

2005-01-01

The aim of this study was to investigate somatosensory and motor cortical activity with functional MRI (fMRI) in a hand-grafted patient with early clinical recovery. The patient had motor fMRI examinations before transplantation, and motor and passive tactile stimulations after surgery. His normal hand and a normal group were studied for comparison. A patient with complete brachial plexus palsy was studied to assess the lack of a fMRI signal in somatosensory areas in the case of total axonal disconnection. Stimulating the grafted hand revealed significant activation in the contralateral somatosensory cortical areas in all fMRI examinations. The activation was seen as early as 10 days after surgery; this effect cannot be explained by the known physiological mechanisms of nerve regeneration. Although an imagination effect cannot be excluded, the objective clinical recovery of sensory function led us to formulate the hypothesis that a connection to the somatosensory cortex was rapidly established. Additional cases and fundamental studies are needed to assess this hypothesis, but several observations were compatible with this explanation. Before surgery, imaginary motion of the amputated hand produced less intense responses than executed movements of the intact hand, whereas the normal activation pattern for right-handed subjects was found after surgery, in agreement with the good clinical motor recovery. (orig.)

An investigation into the Ti-grafting structure on MCM-41 and epoxidation catalysis

DEFF Research Database (Denmark)

Yuan, Q.C.; Hagen, A.; Roessner, F.

2006-01-01

The structure of titanium species grafted on a purely siliceous MCM-41 and their catalysis in the epoxidation of cyclohexene with tert-butyl hydroperoxide (TBHP) were investigated. FT-IR, XANES and UV-vis were used for the examination of the Ti-grafted MCM-41. The results indicated...... that the titanium atoms are grafted on the wall surface of the MCM-41 by four-fold coordination. The four-fold coordinated titanium species are mainly grafted by two or one -O-Si-O- bridges on the MCM-41, resulting in so-called bipodal or monopodal titanium centres in partially polymerised states. The ratio...... of monopodal to bipodal titanium increases with the increase in Ti-content. These partially polymerised titanium species considered as catalytic active centres have high activity and selectivity in the epoxidation reaction. The used Ti-grafted MCM-41 samples were regenerated by heating in nitrogen or air...

Determining the degree of grafting for poly (vinylidene fluoride) graft-copolymers using fluorine elemental analysis

International Nuclear Information System (INIS)

Yu Yang; Zhang Bowu; Yang Xuanxuan; Deng Bo; Li Linfan; Yu Ming; Li Jingye

2011-01-01

Acrylic acid (AAc) and styrene (St) were grafted onto poly (vinylidene fluoride) (PVDF) powder or membrane samples by pre-irradiation graft copolymerization. The grafted chains were proved by FT-IR spectroscopy analysis. The degree of grafting (DG) of the grafted PVDF was determined by fluorine elemental analysis (FEA) method, and was compared with the DGs determined by weighing method, acid-base back titration method and quantitative FT-IR method. The results show that the FEA method is accurate, convenient and universal, especially for the grafted polymer powders. (authors)

Bone grafts in dentistry

Directory of Open Access Journals (Sweden)

Prasanna Kumar

2013-01-01

Full Text Available Bone grafts are used as a filler and scaffold to facilitate bone formation and promote wound healing. These grafts are bioresorbable and have no antigen-antibody reaction. These bone grafts act as a mineral reservoir which induces new bone formation.

Penile Inversion Vaginoplasty with or without Additional Full-Thickness Skin Graft: To Graft or Not to Graft?

Science.gov (United States)

Buncamper, Marlon E; van der Sluis, Wouter B; de Vries, Max; Witte, Birgit I; Bouman, Mark-Bram; Mullender, Margriet G

2017-03-01

Penile inversion vaginoplasty is considered to be the gold standard for gender reassignment surgery in transgender women. The use of additional full-thickness skin graft as neovaginal lining is controversial. Some believe that having extra penile skin for the vulva gives better aesthetic results. Others believe that it gives inferior functional results because of insensitivity and skin graft contraction. Transgender women undergoing penile inversion vaginoplasty were studied prospectively. The option to add full-thickness skin graft is offered in patients where the penile skin length lies between 7 and 12 cm. Neovaginal depth was measured at surgery and during follow-up (3, 13, 26, and 52 weeks postoperatively). Satisfaction with the aesthetic result, neovaginal depth, and dilation regimen during follow-up were recorded. Satisfaction, sexual function, and genital self-image were assessed using questionnaires. A total of 100 patients were included (32 with and 68 without additional full-thickness skin graft). Patient-reported aesthetic outcome, overall satisfaction with the neovagina, sexual function, and genital self-image were not significantly associated with surgical technique. The mean intraoperative neovaginal depth was 13.8 ± 1.4 cm. After 1 year, this was 11.5 ± 2.5 cm. The largest decline (-15 percent) in depth is observed in the first 3 postoperative weeks (p skin graft use, in penile inversion vaginoplasty. The additional use of full-thickness skin graft does not influence neovaginal shrinkage, nor does it affect the patient- and physician-reported aesthetic or functional outcome. Therapeutic, IV.

Reshaping Human Antibodies: Grafting an Antilysozyme Activity

Science.gov (United States)

Verhoeyen, Martine; Milstein, Cesar; Winter, Greg

1988-03-01

The production of therapeutic human monoclonal antibodies by hybridoma technology has proved difficult, and this has prompted the ``humanizing'' of mouse monoclonal antibodies by recombinant DNA techniques. It was shown previously that the binding site for a small hapten could be grafted from the heavy-chain variable domain of a mouse antibody to that of a human myeloma protein by transplanting the hypervariable loops. It is now shown that a large binding site for a protein antigen (lysozyme) can also be transplanted from mouse to human heavy chain. The success of such constructions may be facilitated by an induced-fit mechanism.

Effect of calvarial burring on resorption of onlay cranial bone graft.

Science.gov (United States)

Hassanein, Aladdin H; Clune, James E; Mulliken, John B; Arany, Praveen R; Rogers, Gary F; Kulungowski, Ann M; Greene, Arin K

2012-09-01

Variable resorption occurs whenever calvarial bone graft is used for onlay cranioplasty. The recipient ectocortex may be burred to expose vessels and osteocytes to maximize healing. The purpose of this study was to determine whether abrading the recipient site improves the volume of onlay graft. The parietal bones of 17 rabbits were sectioned into split-thickness and full-thickness grafts. The right frontal cortex was abraded with a bur to punctate bleeding. Pairs of split-thickness (n = 48) or full-thickness (n = 20) grafts were onlayed to the burred right frontal bone and to the nonburred left frontal bone. Micro-computed tomography was used to determine graft volume immediately postoperatively and 16 weeks later. Histology, including tartrate-resistant acid phosphatase staining, was performed to quantify vascular channels and osteoclasts per high-power field 10 days postoperatively. Split-thickness graft volume decreased 58.0% when placed on the burred calvarial site, compared with grafts on the nonburred cortex (28.4%) (P = 0.01). Full-thickness grafts showed a similar trend: greater resorption (39.1%) when onlayed onto abraded calvaria compared with nonburred ectocortex (26.0%) (P = 0.11). Split-thickness graft orientation (cortical vs cancellous side in contact with the recipient site) did not affect resorption (P = 0.67). Onlay grafts placed on the burred recipient site had more vascular channels (11.8) and osteoclasts (5.7), compared with grafts over nonabraded cortex (3.4 and 4.2, respectively) (P cranial bone grafting promotes resorption, possibly by increasing vascularization and osteoclastic activity. This technique cannot be recommended.

A grafting from approach to graft polystyrene chains at the surface of graphene nanolayers by RAFT polymerization: Various graft densities from hydroxyl groups

Energy Technology Data Exchange (ETDEWEB)

Roghani-Mamaqani, Hossein, E-mail: r.mamaghani@sut.ac.ir [Department of Polymer Engineering, Sahand University of Technology, PO Box 51335-1996, Tabriz (Iran, Islamic Republic of); Khezri, Khezrollah [School of Chemistry, University College of Science, University of Tehran, PO Box 14155-6455, Tehran (Iran, Islamic Republic of)

2016-01-01

Graphical abstract: (3-Aminopropyl) triethoxysilane was grafted at the surface of GO in low and high different graft densities to yield GOHAL and GOHAH, respectively. Subsequently, 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid (RA) was attached at the surface of GOHAL and GOHAH by an amidation reaction to yield GOHRL and GOHRH, respectively. Then, GOHRL and GOHRH were used in grafting from RAFT polymerization of styrene. - Highlights: • A RAFT agent grafted GO was used in grafting from RAFT polymerization of styrene. • The efficiency of RAFT agent attachment at the surface of GO is 41.12% for high density sample. • Polystyrene molecular weight is decreased by the addition of graphene content and also graft density of RAFT agent. - Abstract: (3-Aminopropyl) triethoxysilane was grafted at the surface of GO in low and high different graft densities to yield GOHAL and GOHAH, respectively. Subsequently, 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid (RA) was attached at the surface of GOHAL and GOHAH by an amidation reaction to yield GOHRL and GOHRH, respectively. Then, GOHRL and GOHRH were used in grafting from RAFT polymerization of styrene. Grafting of APTES and RA was approved by Fourier transform infrared spectroscopy, X-ray photo electron spectroscopy, and Raman spectroscopy. Expansion of graphene interlayer by oxidation and functionalization processes was evaluated by X-ray diffraction. Conversion values of styrene were calculated using gas chromatography. Molecular weight and PDI values of attached polystyrene (PS) chains were studied by size exclusion chromatography. Thermogravimetric analysis was also used to investigate the degradation temperatures, char contents, and graft contents of modifiers and PS chains. GOHRH and GOHRL reach to char content of 55.3 and 45.2% at 600 °C, which shows that weight ratio of modifier (APTES and RA moieties) is 15.3 and 5.2%, respectively. Scanning and transmission electron microscopies show that

Current status of grafts and implants in rhinoplasty: Part II. Homologous grafts and allogenic implants.

Science.gov (United States)

Sajjadian, Ali; Naghshineh, Nima; Rubinstein, Roee

2010-03-01

After reading this article, the participant should be able to: 1. Understand the challenges in restoring volume and structural integrity in rhinoplasty. 2. Identify the appropriate uses of various homologous grafts and allogenic implants in reconstruction, including: (a) freeze-dried acellular allogenic cadaveric dermis grafts, (b) irradiated cartilage grafts, (c) hydroxyapatite mineral matrix, (d) silicone implants, (e) high-density polyethylene implants, (f) polytetrafluoroethylene implants, and (g) injectable filler materials. 3. Identify the advantages and disadvantages of each of these biomaterials. 4. Understand the specific techniques that may aid in the use these grafts or implants. This review specifically addresses the use of homologous grafts and allogenic implants in rhinoplasty. It is important to stress that autologous materials remain the preferred graft material for use in rhinoplasty, owing to their high biocompatibility and low risk of infection and extrusion. However, concerns of donor-site morbidity, graft availability, and graft resorption have motivated the development and use of homologous and allogenic implants.

Vein grafting in fingertip replantations.

Science.gov (United States)

Yan, Hede; Jackson, William D; Songcharoen, Somjade; Akdemir, Ovunc; Li, Zhijie; Chen, Xinglong; Jiang, Liangfu; Gao, Weiyang

2009-01-01

In this retrospective study, the survival rates of fingertip replantation with and without vein grafting were evaluated along with their postoperative functional and cosmetic results. One hundred twenty-one-fingertip amputations were performed in 103 patients between September 2002 and July 2007. Thirty-four amputated fingertips were replanted without vein grafting, while 87 amputated fingertips were replanted with vein grafting for arterial and/or venous repairs. The overall survival rates of the replantations with and without vein grafting were 90% (78/87) and 85% (29/34), respectively. The survival rates were 88% (36/41) with venous repair, 93% (25/27) with arterial repair, and 89% (17/19) with both. Nineteen patients without vein grafting and 48 patients with vein grafting had a follow-up period of more than one year. Good cosmetic and functional outcomes were observed in both groups of patients. The results show that vein grafting is a reliable technique in fingertip replantations, showing no significant difference (P > 0.05) in survival between those with and without vein grafting. Furthermore, no significant difference (P > 0.05) in survival was found between cases with vein grafts for arterial and/or venous repairs. In fingertip replantations with vein grafting, favorable functional and esthetic results can be achieved without sacrificing replantation survival. (c) 2009 Wiley-Liss, Inc.

Removal of Industrial Pollutants From Wastewater's By Graft Copolymers

International Nuclear Information System (INIS)

Hegazy El-Sayed, A.; El-Nagar Abdel-Wahab, M.; Senna Magdy, M.; Zahran Abdel-Hamid, H.

1999-01-01

Graft copolymers that obtained by radiation grafting of acrylic acid and acrylamide onto LDPE film were converted to N-hydroxy ethyl amide and hydroxamic acid derivatives respectively. The possible application for the different prepared chemical derivatives of LDPE graft copolymers in metal adsorption from solutions containing a single cation or simulated medium active waste has been investigated. The results showed that the adsorption of Cu(II) metal by different chemical derivatives was greatly affected by different factors such as graft yield, ph value, concentration of metal in the feed solution, immersion time and treatment temperature. The affinity of N-hydroxy ethyl amide derivative toward the different metals was found to be in the order of; Cu(II) >Pd(II) > Cd(II)> Co(II). However, for hydroxamic acid derivative , the affinity order was: Cd(II) > Cu(II) > Co(II). The ESR and IR analysis revealed that the metal ions are chelated through the lone pair of electrons on the -OH and -NH- groups forming a ring structure. The measured metal ion uptake from simulated medium active waste mixture by N-hydroxy ethyl amide derivative was found to follow the following order: Fe> U> Ni> Zr> Zn> Cr. On the other hand, the measured metal uptake by hydroxamic acid derivative was found to follow: Fe>U> Zr> Ca. It is concluded that the prepared grafted copolymers are of interest for metal chelation and could be applied in the field of waste treatment

Systemic treatment with n-6 polyunsaturated fatty acids attenuates EL4 thymoma growth and metastasis through enhancing specific and non-specific anti-tumor cytolytic activities and production of TH1 cytokines.

Science.gov (United States)

Salem, Mohamed Labib

2005-06-01

Recently, there has been a great interest in the effects of different types of n-6 polyunsaturated acids (n-6 PUFAs) upon the immune system and cancer development. However, the effects of n-6 PUFAs are still controversial and as yet undefined. The present study aimed to investigate the anti-tumor effects of n-6 PUFAs against EL4 thymoma and the associated immune mechanisms. To this, sesame oil, a vegetable oil enriched with n-6 PUFAs, or free linoleic acid (LA) were administered intraperitoneally into C57BL/6 mice before and after challenge with EL4 lymphoma cells. Treatment with either sesame oil or LA attenuated the growth and metastasis of EL4 lymphoma. The anti-tumor effect of LA was superior to that of sesame oil, and associated with an increase in the survival rate of the tumor-bearing mice. In addition, both sesame oil and LA showed dose-dependent anti-lymphoma growth in vitro. Treatment with LA generated significant increases in the anti-lymphoma cytolytic and cytostatic activities of T cells and macrophages, respectively, and enhanced production of IL-2 and IFN-gamma while decreased production of IL-4, IL-6 and IL-10. In summation, the results suggest that n-6 PUFAs, represented by LA, can attenuate EL4 lymphoma growth and metastasis through enhancing the specific and non-specific anti-tumor cytolytic activities and production of TH1 cytokines. These findings might be of great importance for a proper design of systemic nourishment with PUFAs emulsions for cancer patients.

Cadmium stress antioxidant responses and root-to-shoot communication in grafted tomato plants.

Science.gov (United States)

Gratão, Priscila Lupino; Monteiro, Carolina Cristina; Tezotto, Tiago; Carvalho, Rogério Falleiros; Alves, Letícia Rodrigues; Peters, Leila Priscila; Azevedo, Ricardo Antunes

2015-10-01

Many aspects related to ROS modulation of signaling networks and biological processes that control stress responses still remain unanswered. For this purpose, the grafting technique may be a powerful tool to investigate stress signaling and specific responses between plant organs during stress. In order to gain new insights on the modulation of antioxidant stress responses mechanisms, gas-exchange measurements, lipid peroxidation, H2O2 content, proline, superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), ascorbate peroxidase (APX) and guaiacol peroxidase (GPOX) were analyzed in Micro-Tom grafted plants submitted to cadmium (Cd). The results observed revealed that higher amounts of Cd accumulated mainly in the roots and rootstocks when compared to leaves and scions. Macronutrients uptake (Ca, S, P and Mg) decreased in non-grafted plants, but differed among plant parts in all grafted plants. The results showed that the accumulation of proline observed in scions of grafted plants could be associated to the lower MDA contents in the scions of grafted plants. In the presence of Cd, non-grafted plants displayed increased CAT, GR, GPOX and APX activities for both tissues, whilst grafted plants revealed distinct trends that clearly indicate signaling responses from the rootstocks, allowing sufficient time to activate defense mechanisms in shoot. The information available concerning plants subjected to grafting can provide a better understanding of the mechanisms of Cd detoxification involving root-to-shoot signaling, opening new possibilities on strategies which can be used to manipulate heavy metal tolerance, since antioxidant systems are directly involved in such mechanism.

Radiation chemical grafting of vinyl acetate and styrene on nitrocellulose

International Nuclear Information System (INIS)

Chapiro, A.; Foex, M.; Jendrychowska-Bonamour, A.M.

1977-01-01

Vinyl acetate and styrene were grafted onto nitrocellulose using the direct radiation grafting technique with 500 and 3000 Ci 60 Co γ sources. For vinyl acetate, the reaction proceeds homogeneously. The kinetics are dominated by degradative chain transfer to the nitrocellulose. The polymerization of vinyl acetate was examined in the presence of isoamyl nitrate, a model for nitrocellulose; the transfer constant was determined and the results are treated semi-quantitatively. For styrene, grafting occurs in a swollen film irradiated in the presence of excess monomer. The diffusion of styrene into nitrocellulose is extremely slow; methanol was added to the reaction mixture to favour diffusion which was found to obey Fick's law. The diffusion constant and activation energy of diffusion are evaluated. The grafting kinetics are controlled by monomer diffusion, accounting for the increase of dose-rate exponent with temperature. A spontaneous grafting process occurs in the absence of irradiation. It is initiated by macroradicals arising from thermal decomposition of nitrocellulose. (author)

Application of Biological Tissue Grafts for Burns in Zambia

International Nuclear Information System (INIS)

Chishimba, Gershom

2001-01-01

The author discusses the advances made in the use of Biological Tissue Grafts for the treatment of burns.The paper outlines research activities and clinical trials done in the use of gamma radiation sterilised Amnion membranes and Pig skin grafts in the zambian Heath Care System for treatment of Burns.Ethical issues of Tissue Banking are also discussed in relation to religious and cultural beliefs and Good Manufacturing Practices

Determination of the distribution of graft yields following a radiation-induced graft copolymerization

International Nuclear Information System (INIS)

Schipschack, K.; Wagner, H.; Sawtschenko, L.

1976-01-01

In the radiation-induced graft copolymerization on solid initial polymers a distribution of graft yields takes place along the cross-sections of samples. Methods for determining this distribution, which are described in the literature, are reviewed. In our own investigations boards made of ethylene-vinyl acetate copolymers and grafted with vinyl chloride were used. Distributions of the grafted component obtained by infrared analysis of microtome cuts parallel to the surface are partly rather inhomogeneous, and are interpreted as dependent on the experimental parameters. (author)

Study on grafting glycidyl methacrylate onto HDPE membranes by pre-irradiation graft copolymerization

International Nuclear Information System (INIS)

Tong Long; Zu Jianhua; Liu Xinwen; Sun Guisheng; Yu Chunhui

2006-01-01

Glycidyl methacrylate (GMA) was grafted onto HDPE membranes by pre-irradiation method with 1.8 MeV E-beam and a kind of membranes having reactive epoxy groups was successfully synthesized. Effects of monomer concentration, reaction temperature and time and irradiation dose on the grafting yield were studied. Composition, thermo-property and surface morphology of the grafted membranes were studied by FTIR, DSC and Tapping-mode AFM, respectively. The FTIR measurements proved the synthesized copolymer is HDPE-g-GMA. The DSC results indicated the grafted HDPE's melting temperature (T m ) and heat of fusion (ΔH f ( HDPE) ) which was reduced with increasing grafting yield. The AFM images indicated that surface of the HDPE-g-GMA membranes was rougher than the virgin HDPE. (authors)

Dependence of crystallinity degree with induced grafting by gamma radiation of N,N'-dimethyl acrylamide

International Nuclear Information System (INIS)

Queiroz, A.A.A.; Higa, O.Z.; Barrak, E.R.; Giolito, I.

1991-01-01

N,N' -dimethyl acrylamide (DMAA) graft copolymerization onto polyethylene films was carried out, using a organic solvent as a reaction medium and gamma rays from a 60 Co source for surface activation. Thermal analysis revealed the crystallinity and the grafting inversely proportional. The DSC curves fusion peaks decreased with grafting rate increase, the peak almost disappearing in the curve of PE 440% grafted. It was concluded that the graft occurs not only on the surface but also in the substrate bulk, being the PE absorption of DMAA an important factor for build up of grafted mass. (author)

Prevention of primary vascular graft infection with silver-coated polyester graft in a porcine model

DEFF Research Database (Denmark)

Gao, H; Sandermann, J; Prag, J

2010-01-01

To evaluate the efficacy of a silver-coated vascular polyester graft in the prevention of graft infection after inoculation with Staphylococcus aureus in a porcine model.......To evaluate the efficacy of a silver-coated vascular polyester graft in the prevention of graft infection after inoculation with Staphylococcus aureus in a porcine model....

Skin graft - slideshow

Science.gov (United States)

... this page: //medlineplus.gov/ency/presentations/100100.htm Skin graft - series—Normal anatomy To use the sharing features ... entire body, and acts as a protective barrier. Skin grafts may be recommended for: Extensive wounds Burns Specific ...

Lycopene and flesh colour differences in grafted and non-grafted watermelon

OpenAIRE

Fekete D.; Stéger-Máté M.; Bőhm V.; Balázs G.; Kappel N.

2015-01-01

The experiment was carried out in three regions in Hungary (Jászszentandrás, Cece, Újkígyós) in 2013 to determine the fruit quality of grafted watermelon (Citrullus lanatus Thunb.). The “RX 467” seedless watermelon variety was grafted on two commercial rootstocks “FR STRONG” [Lagenaria siceraria (Mol.) Standl.] and “RS 841” (Cucurbita maxima Duchesne × Cucurbita moschata Duchesne). The lycopene and flesh colours are important quality characteristics even of the selfrooted and grafted watermel...

A new grafting technique for tympanoplasty: tympanoplasty with a boomerang-shaped chondroperichondrial graft (TwBSCPG).

Science.gov (United States)

Dündar, Rıza; Soy, Fatih Kemal; Kulduk, Erkan; Muluk, Nuray Bayar; Cingi, Cemal

2014-10-01

The aim of this study was to introduce a new grafting technique in tympanoplasty that involves use of a boomerang-shaped chondroperichondrial graft (BSCPG). The anatomical and functional results were evaluated. A new tympanoplasty with boomerang-shaped chondroperichondrial graft (TwBSCPG) technique was used in 99 chronic otitis media patients with central or marginal perforation of the tympanic membrane and a normal middle ear mucosa. All 99 patients received chondroperichondrial cartilage grafts with a boomerang-shaped cartilage island left at the anterior and inferior parts. Postoperative follow-ups were conducted at months 1, 6, and 12. Preoperative and postoperative audiological examinations were performed and air-bone gaps were calculated according to the pure-tone averages (PTAs) of the patients. In the preoperative period, most (83.8%) air-bone gaps were ≥ 16 dB; after operating using the TwBSCPG technique, the air-bone gaps decreased to 0-10 dB in most patients (77.8%). In the TwBSCPG patients, the mean preoperative air-bone gap was 22.02 ± 6.74 dB SPL. Postoperatively, the mean postoperative air-bone gap was 8.70 ± 5.74 dB SPL. The TwBSCPG technique therefore decreased the postoperative air-bone gap compared to that preoperatively (p = 0.000, z = -8.645). At the 1-month follow-up, there were six graft perforations and one graft retraction. At the 6-month follow-up, there were nine graft perforations and three graft retractions. At 12 months, there were seven graft perforations and four graft retractions. During the first year after the boomerang tympanoplasty surgery, graft lateralization was not detected in any patient. Retractions were grade 1 according to the Sade classification and were localized to the postero-superior quadrant of the tympanic membrane. The TwBSCPG technique has benefits with respect to postoperative anatomical and audiological results. It prevents perforation of the tympanic membrane at the anterior quadrant and avoids graft

Angiographic Evaluation of Carotid Artery Grafting with Prefabricated Small-Diameter, Small-Intestinal Submucosa Grafts in Sheep

International Nuclear Information System (INIS)

Pavcnik, Dusan; Obermiller, Josef; Uchida, Barry T.; Van Alstine, William; Edwards, James M.; Landry, Gregory J.; Kaufman, John A.; Keller, Frederick S.; Roesch, Josef

2009-01-01

The purpose of this study was to report the longitudinal angiographic evaluation of prefabricated lyophilized small-intestinal submucosa (SIS) grafts placed in ovine carotid arteries and to demonstrate a variety of complications that developed. A total of 24 grafts, 10 cm long and 6 mm in diameter, were placed surgically as interposition grafts. Graft patency at 1 week was evaluated by Doppler ultrasound, and angiography was used for follow-up at 1 month and at 3 to 4 months. A 90% patency rate was found at 1 week, 65% at 1 month, and 30% at 3 to 4 months. On the patent grafts, angiography demonstrated a variety of changes, such as anastomotic stenoses, graft diffuse dilations and dissections, and aneurysm formation. These findings have not been previously demonstrated angiographically by other investigators reporting results with small-diameter vessel grafts made from fresh small-intestinal submucosa (SIS). The complications found were partially related to the graft construction from four SIS layers. Detailed longitudinal angiographic study should become an essential part of any future evaluation of small-vessel SIS grafting.

Au-nanoparticles grafted on plasma treated PE

International Nuclear Information System (INIS)

Svorcik, V.; Chaloupka, A.; Rezanka, P.; Slepicka, P.; Kolska, Z.; Kasalkova, N.; Hubacek, T.; Siegel, J.

2010-01-01

Polyethylene (PE) surface was treated with Ar plasma. Activated surface was grafted from methanol solution of 1,2-ethanedithiol. Then the sample was immersed into freshly prepared colloid solution of Au-nanoparticles. Finally Au layer was sputtered on the samples. Properties of the modified PE were studied using various methods: AFM, EPR, RBS and nanoindentation. It was shown that the plasma treatment results in degradation of polymer chain (AFM) and creation of free radicals by EPR. After grafting with dithiol, the concentration of free radicals declines. The presence of Au and S in the surface layer after the coating with Au-nanoparticles was proved by RBS. Plasma treatment changes PE surface morphology and increases surface roughness, too. Another significant change in surface morphology and roughness was observed after deposition of Au-nanoparticles. Nanoindentation measurements show that the grafting with Au-nanoparticles increases adhesion of subsequently sputtered Au layer.

Impact of bone graft harvesting techniques on bone formation and graft resorption

DEFF Research Database (Denmark)

Saulacic, Nikola; Bosshardt, Dieter D; Jensen, Simon S

2015-01-01

BACKGROUND: Harvesting techniques can affect cellular parameters of autogenous bone grafts in vitro. Whether these differences translate to in vivo bone formation, however, remains unknown. OBJECTIVE: The purpose of this study was to assess the impact of different harvesting techniques on bone fo......: Transplantation of autogenous bone particles harvested with four techniques in the present model resulted in moderate differences in terms of bone formation and graft resorption.......BACKGROUND: Harvesting techniques can affect cellular parameters of autogenous bone grafts in vitro. Whether these differences translate to in vivo bone formation, however, remains unknown. OBJECTIVE: The purpose of this study was to assess the impact of different harvesting techniques on bone...... formation and graft resorption in vivo. MATERIAL AND METHODS: Four harvesting techniques were used: (i) corticocancellous blocks particulated by a bone mill; (ii) bone scraper; (iii) piezosurgery; and (iv) bone slurry collected from a filter device upon drilling. The grafts were placed into bone defects...

Adolescent External Iliac Artery Trauma: Recurrent Aneurysmal Dilatation of an Iliofemoral Saphenous Vein Graft Treated by Stent-Grafting

International Nuclear Information System (INIS)

Lenton, James; Davies, John; Homer-Vanniasinkam, S.; McPherson, Simon

2008-01-01

An adolescent male sustained a severe penetrating injury to the external iliac artery. Emergency surgical revascularization was with a reversed long saphenous vein interposition graft. The primary graft and the subsequent revision graft both became aneurysmal. The second graft aneurysm was successfully excluded by endovascular stent-grafts with medium-term primary patency. A venous graft was used initially rather than a synthetic graft to reduce the risk of infection and the potential problems from future growth. Aneurysmal dilatation of venous grafts in children and adolescents is a rare but recognized complication. To the best of our knowledge, exclusion of these aneurysms with stent-grafts has not been previously reported in the adolescent population.

Compliance Study of Endovascular Stent Grafts Incorporated with Polyester and Polyurethane Graft Materials in both Stented and Unstented Zones

Directory of Open Access Journals (Sweden)

Ying Guan

2016-08-01

Full Text Available Compliance mismatch between stent graft and host artery may induce complications and blood flow disorders. However, few studies have been reported on stent graft compliance. This study aims to explore the deformation and compliance of stent graft in stented and unstented zones under three pressure ranges. Compliance of two stent grafts incorporated with polyurethane graft (nitinol-PU and polyester graft (nitinol-PET materials respectively were tested; the stents used in the two stent grafts were identical. For the circumferential deformation of the stent grafts under each pressure range, the nitinol-PET stent graft was uniform in both zones. The nitinol-PU stent graft was circumferentially uniform in the stented zone, however, it was nonuniform in the unstented zone. The compliance of the PU graft material was 15 times higher than that of the PET graft. No significant difference in compliance was observed between stented and unstented zones of the nitinol-PET stent graft regardless of the applied pressure range. However, for the nitinol-PU stent graft, compliance of the unstented PU region was approximately twice that of the stented region; thus, compliance along the length of the nitinol-PU stent graft was not constant and different from that of the nitinol-PET stent graft.

Depth of the graft bed influences split-skin graft contraction.

NARCIS (Netherlands)

Mensik, I.; Lamme, E.N.; Brychta, P.

2003-01-01

Contraction of a split-thickness skin graft used for coverage of large defects remains a great problem in plastic, burn and reconstructive surgery. In this study we evaluated healing of split-thickness skin grafts transplanted in wounds on the subcutaneous fat and muscle fascia in pigs. Four young

Enhanced CO2 Adsorption on Activated Carbon Fibers Grafted with Nitrogen-Doped Carbon Nanotubes

Directory of Open Access Journals (Sweden)

Yu-Chun Chiang

2017-05-01

Full Text Available In this paper, multiscale composites formed by grafting N-doped carbon nanotubes (CNs on the surface of polyamide (PAN-based activated carbon fibers (ACFs were investigated and their adsorption performance for CO2 was determined. The spaghetti-like and randomly oriented CNs were homogeneously grown onto ACFs. The pre-immersion of cobalt(II ions for ACFs made the CNs grow above with a large pore size distribution, decreased the oxidation resistance, and exhibited different predominant N-functionalities after chemical vapor deposition processes. Specifically, the CNs grafted on ACFs with or without pre-immersion of cobalt(II ions were characterized by the pyridine-like structures of six-member rings or pyrrolic/amine moieties, respectively. In addition, the loss of microporosity on the specific surface area and pore volume exceeded the gain from the generation of the defects from CNs. The adsorption capacity of CO2 decreased gradually with increasing temperature, implying that CO2 adsorption was exothermic. The adsorption capacities of CO2 at 25 °C and 1 atm were between 1.53 and 1.92 mmol/g and the Freundlich equation fit the adsorption data well. The isosteric enthalpy of adsorption, implying physical adsorption, indicated that the growth of CNTs on the ACFs benefit CO2 adsorption.

Bone scintigraphy in evaluating the viability of composite bone grafts revascularized by microvascular anastomoses, conventional autogenous bone grafts, and free non-revascularized periosteal grafts

International Nuclear Information System (INIS)

Berggren, A.; Weiland, A.J.; Ostrup, L.T.

1982-01-01

Researchers studied the value of bone scintigraphy in the assessment of anastomotic patency and bone-cell viability in free bone grafts revascularized by microvascular anastomoses in twenty-seven dogs. The dogs were divided into three different groups, and scintigraphy was carried out using technetium-labeled methylene diphosphonate in composite bone grafts revascularized by microvascular anastomoses, conventional autogenous bone grafts, and periosteal grafts placed in different recipient beds. The viability of the grafts were evaluated by histological examination and fluorescence microscopy after triple labeling with oxytetracycline on the first postoperative day, alizarin complexone on the fourth postoperative day, and DCAF on the eleventh postoperative day. A positive scintiscan within the first week following surgery indicated patent microvascular anastomoses, and histological study and fluorescence microscopy confirmed that bone throughout the graft was viable. A positive scintiscan one week after surgery or later does not necessarily indicate microvascular patency or bone-cell survival, because new bone formed by creeping substitution on the surface of a dead bone graft can result in this finding

Some investigations on the post radiation grafting of acrylamide onto polyethylene films

International Nuclear Information System (INIS)

Hegazy, E-S.A.; El-Dessouky, M.M.; El-Sharabasy, S.A.

1986-01-01

A study has been made on the post radiation grafting of aqueous acrylamide onto low density polyethylene film. It was found that the addition of 0.05 wt % Mohr's salt reduced effectively the homopolymerization of acrylamide and the grafting process was successfully achieved. The dependence of the grafting rate on the preirradiation dose and monomer concentration was found to be of 1.43 and 1.4 order, respectively. The overall activation energy for the graft polymerization was found to be 13.5 and 1.95 Kcal/mol below and above 45 0 C, respectively. Some properties of the graft co-polymer such as swelling behaviour, electrical conductivity, and reverse osmosis desalination of saline water (water flux and salt rejection), were also investigated and the possibility of its uses in the practical applications was discussed. (author)

Osseous scintigraphy and auxiliary graft

International Nuclear Information System (INIS)

Khelifa, F.; Siles, S.; Puech, B.

1992-01-01

The scintigraphy could be a good way to survey the osseous graft: three cases are studied in which were recognized the presence of a graft, surinfection, graft lysis, pseudo-arthrosis, algodystrophy. 8 refs., 5 figs

Similar Outcomes in Diabetes Patients After Coronary Artery Bypass Grafting With Single Internal Thoracic Artery Plus Radial Artery Grafting and Bilateral Internal Thoracic Artery Grafting.

Science.gov (United States)

Raza, Sajjad; Blackstone, Eugene H; Houghtaling, Penny L; Koprivanac, Marijan; Ravichandren, Kirthi; Javadikasgari, Hoda; Bakaeen, Faisal G; Svensson, Lars G; Sabik, Joseph F

2017-12-01

The purpose of this study was to determine in patients with diabetes mellitus whether single internal thoracic artery (SITA) plus radial artery (RA) grafting yields outcomes similar to those of bilateral internal thoracic artery (BITA) grafting. From January 1994 to January 2011, 1,325 diabetic patients underwent primary isolated coronary artery bypass graft surgery with either (1) SITA plus RA with or without saphenous vein (SV) grafts (n = 965) or (2) BITA with or without SV grafts (n = 360); an internal thoracic artery was used in all patients to graft the left anterior descending coronary artery. Endpoints were in-hospital outcomes and time-related mortality. Median follow-up was 7.4 years, with a total follow-up of 9,162 patient-years. Propensity score matching was performed to identify 282 well-matched pairs for adjusted comparisons. Unadjusted in-hospital mortality was 0.52% for SITA plus RA with or without SV grafts and 0.28% for BITA with or without SV grafts, and prevalence of deep sternal wound infection was 3.2% and 1.7%, respectively. Unadjusted survival at 1, 5, 10, and 14 years was 97%, 88%, 68%, and 51% for SITA plus RA with or without SV grafts, and 97%, 95%, 80%, and 66% for BITA with or without SV grafts, respectively. Among propensity-matched patients, in-hospital mortality (0.35% versus 0.35%) and prevalence of deep sternal wound infection (1.4% versus 1.4%) were similar (p > 0.9) in the two groups, as was 1-, 5-, 10-, and 14-year survival: 97%, 90%, 70%, and 58% for SITA plus RA with or without SV grafting versus 97%, 93%, 79%, and 64% for BITA with or without SV grafting, respectively (early p = 0.8, late p = 0.2). For diabetic patients, SITA plus RA with or without SV grafting and BITA with or without SV grafting yield similar in-hospital outcomes and long-term survival after coronary artery bypass graft surgery. Therefore, both SITA plus RA and BITA plus SV grafting should be considered for these patients. Copyright © 2017 The Society

Synthesis, characterization, bioactivity and potential application of phenolic acid grafted chitosan: A review.

Science.gov (United States)

Liu, Jun; Pu, Huimin; Liu, Shuang; Kan, Juan; Jin, Changhai

2017-10-15

In recent years, increasing attention has been paid to the grafting of phenolic acid onto chitosan in order to enhance the bioactivity and widen the application of chitosan. Here, we present a comprehensive overview on the recent advances of phenolic acid grafted chitosan (phenolic acid-g-chitosan) in many aspects, including the synthetic method, structural characterization, biological activity, physicochemical property and potential application. In general, four kinds of techniques including carbodiimide based coupling, enzyme catalyzed grafting, free radical mediated grafting and electrochemical methods are frequently used for the synthesis of phenolic acid-g-chitosan. The structural characterization of phenolic acid-g-chitosan can be determined by several instrumental methods. The physicochemical properties of chitosan are greatly altered after grafting. As compared with chitosan, phenolic acid-g-chitosan exhibits enhanced antioxidant, antimicrobial, antitumor, anti-allergic, anti-inflammatory, anti-diabetic and acetylcholinesterase inhibitory activities. Notably, phenolic acid-g-chitosan shows potential applications in many fields as coating agent, packing material, encapsulation agent and bioadsorbent. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydrophilic/hydrophobic character of grafted cellulose

Energy Technology Data Exchange (ETDEWEB)

Takacs, E., E-mail: takacs@iki.kfki.h [Institute of Isotopes, Hungarian Academy of Sciences, Budapest (Hungary); Wojnarovits, L. [Institute of Isotopes, Hungarian Academy of Sciences, Budapest (Hungary); Borsa, J. [Budapest University of Technology and Economics (Hungary); Racz, I. [Bay Zoltan Institute for Materials Science and Technology, Budapest (Hungary)

2010-04-15

Vinyl monomers with long paraffin chains were grafted onto two kinds of cellulose (cotton and cotton linter) by direct irradiation grafting technique. The effect of dose, monomer structure and concentration, as well as homopolymer suppressor (styrene) concentration on the grafting yield was studied and the optimal grafting conditions were established. Grafting decreased the swelling of the samples in water and increased their polymer compatibility in polypropylene matrix.

Haemodynamics in axillobifemoral bypass grafts

NARCIS (Netherlands)

C.H. Wittens

1992-01-01

textabstractThis thesis is based on four publications on the subject of graft configuration and haemodynamics in axillobifemoral bypass grafts: 1. A clinical evaluation of 17 patients with axillobifemoral bypass graft operations, performed for various indications. Two important observations were

Renographic indices for evaluation of changes in graft function

Energy Technology Data Exchange (ETDEWEB)

El-Maghraby, T.A.F.; Eck-Smit, B.L.F. van; Pauwels, E.K.J. [Division of Nuclear Medicine, Department of Radiology, Leiden University Medical Centre, Leiden (Netherlands); Fijter, J.W. de [Department of Nephrology, Leiden University Medical Centre, Leiden (Netherlands); Zwinderman, A.H. [Department of Medical Statistics, Leiden University Medical Centre, Leiden (Netherlands); El-Haddad, S.I. [Department of Oncology and Nuclear Medicine, Cairo University (Egypt)

1998-11-01

Radionuclide renal diagnostic studies play an important role in assessing renal allograft function, especially in the early post-transplant period. In the past two decades various quantitative parameters have been derived from the radionuclide renogram to evaluate changes in perfusion and/or function of the kidney allograft. In this review article we discuss the quantitative parameters that have been used to assess graft condition, with emphasis on the early postoperative period. These quantitative methods are divided into parameters used for assessing renal graft perfusion and parameters used for evaluating parenchymal function. The blood flow in renal transplants can be quantified (a) by measuring the rate of activity appearance in the kidney graft, (b) by calculating the ratio of the integral activity under the transplanted kidney and arterial curves and (c) by calculating the renal vascular transit time. In this article we review a number of parenchymal uptake and excretion indices, such as the accumulation index, the graft uptake capacity at 2 and 10 min, the excretion index and the elimination index. The literature on these parameters shows that they have some practical disadvantages. In addition, values suffer from significant overlap when various graft pathologies coexist. A retrospective study was designed in our institution to evaluate the clinical usefulness of some of the frequently used previously published methods in which the graft function is quantitatively assessed in the early post-transplant period. The quantitative parameters studied which were reasonably reproducible in our hands included: global perfusion index (GPI), cortical perfusion index (CPI), vascular transit time, and the parenchymal parameters uptake capacity at 2 min (UC{sub 2}) and elimination index (K{sub 3/20}). The patient population in this study consisted of 43 patients with 157 technetium-99m mercaptylacetyltriglycine renograms. The perfusion indices GPI and CPI did not allow

Biodegradability of poly(3-hydroxybutyrate) film grafted with vinyl acetate: Effect of grafting and saponification

Science.gov (United States)

Wada, Yuki; Seko, Noriaki; Nagasawa, Naotsugu; Tamada, Masao; Kasuya, Ken-ichi; Mitomo, Hiroshi

2007-06-01

Radiation-induced graft polymerization of vinyl acetate (VAc) onto poly(3-hydroxybutyrate) (PHB) film was carried out. At a degree of grafting higher than 5%, the grafted films (PHB-g-VAc) completely lost the enzymatic degradability that is characteristic of PHB due to the grafted VAc covering the surface of the PHB film. However, the biodegradability of the PHB-g-VAc films was recovered when the films were saponified in alkali solution under optimum conditions. Graft chains of the PHB-g-VAc film reacted selectively to become biodegradable polyvinyl alcohol (PVA). The biodegradability of the saponified PHB-g-VAc film increased rapidly with time.

Biodegradability of poly(3-hydroxybutyrate) film grafted with vinyl acetate: Effect of grafting and saponification

International Nuclear Information System (INIS)

Wada, Yuki; Seko, Noriaki; Nagasawa, Naotsugu; Tamada, Masao; Kasuya, Ken-ichi; Mitomo, Hiroshi

2007-01-01

Radiation-induced graft polymerization of vinyl acetate (VAc) onto poly(3-hydroxybutyrate) (PHB) film was carried out. At a degree of grafting higher than 5%, the grafted films (PHB-g-VAc) completely lost the enzymatic degradability that is characteristic of PHB due to the grafted VAc covering the surface of the PHB film. However, the biodegradability of the PHB-g-VAc films was recovered when the films were saponified in alkali solution under optimum conditions. Graft chains of the PHB-g-VAc film reacted selectively to become biodegradable polyvinyl alcohol (PVA). The biodegradability of the saponified PHB-g-VAc film increased rapidly with time

Surface modification of polypropylene membrane by polyethylene glycol graft polymerization

Energy Technology Data Exchange (ETDEWEB)

Abednejad, Atiye Sadat, E-mail: atiyeabednejad@gmail.com [Department of Biomedical Engineering, Faculty of New Sciences and Technologies, University of Tehran, P.O. Box 14395-1561, Tehran (Iran, Islamic Republic of); Amoabediny, Ghasem [Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, P.O. Box 14395-1561, Tehran (Iran, Islamic Republic of); Research Center for New Technologies in Life Science Engineering, University of Tehran, P.O. Box 63894-14179, Tehran (Iran, Islamic Republic of); Ghaee, Azadeh [Department of Biomedical Engineering, Faculty of New Sciences and Technologies, University of Tehran, P.O. Box 14395-1561, Tehran (Iran, Islamic Republic of)

2014-09-01

Polypropylene hollow fiber microporous membranes have been used in a wide range of applications, including blood oxygenator. The hydrophobic feature of the polypropylene surface causes membrane fouling. To minimize fouling, a modification consisting of three steps: surface activation in H{sub 2} and O{sub 2} plasma, membrane immersion in polyethylene glycol (PEG) and plasma graft polymerization was performed. The membranes were characterized by contact angle measurement, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), tensile test, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Oxygen transfer of modified membranes was also tested. The stability of grafted PEG was measured in water and in phosphate buffer saline (PBS) at 37 °C. Blood compatibility of modified surfaces was evaluated by the platelet adhesion method. Water contact angel reduction from 110° to 72° demonstrates the enhanced hydrophilicity, and XPS results verify the presence of oxygenated functional groups due to the peak existence in 286 eV as a result of PEG grafting. The results clearly indicate that plasma graft-polymerization of PEG is an effective way for antifouling improvement of polypropylene membranes. Also, the results show that oxygen transfer changes in PEG grafted membranes are not significant. - Highlights: • H{sub 2} and O{sub 2} plasma graft polymerization of PEG on polypropylene membrane was carried out. • Changes in surface properties were investigated by FTIR, XPS, SEM, and AFM. • Surface wettability enhanced as a result of poly ethylene glycol grafting. • PEG grafting degree increase causes reduction of fouling and adhesion.

Radiation grafting on natural films

Science.gov (United States)

Lacroix, M.; Khan, R.; Senna, M.; Sharmin, N.; Salmieri, S.; Safrany, A.

2014-01-01

Different methods of polymer grafting using gamma irradiation are reported in the present study for the preparation of newly functionalized biodegradable films, and some important properties related to their mechanical and barrier properties are described. Biodegradable films composed of zein and poly(vinyl alcohol) (PVA) were gamma-irradiated in presence of different ratios of acrylic acid (AAc) monomer for compatibilization purpose. Resulting grafted films (zein/PVA-g-AAc) had their puncture strength (PS=37-40 N mm-1) and puncture deformation (PD=6.5-9.8 mm) improved for 30% and 50% PVA in blend, with 5% AAc under 20 kGy. Methylcellulose (MC)-based films were irradiated in the presence of 2-hydroxyethyl methacrylate (HEMA) or silane, in order to determine the effect of monomer grafting on the mechanical properties of films. It was found that grafted films (MC-g-HEMA and MC-g-silane) using 35% monomer performed higher mechanical properties with PS values of 282-296 N mm-1 and PD of 5.0-5.5 mm under 10 kGy. Compatibilized polycaprolactone (PCL)/chitosan composites were developed via grafting silane in chitosan films. Resulting trilayer grafted composite film (PCL/chitosan-g-silane/PCL) presented superior tensile strength (TS=22 MPa) via possible improvement of interfacial adhesion (PCL/chitosan) when using 25% silane under 10 kGy. Finally, MC-based films containing crystalline nanocellulose (CNC) as a filling agent were prepared and irradiated in presence of trimethylolpropane trimethacrylate (TMPTMA) as a grafted plasticizer. Grafted films (MC-g-TMPTMA) presented superior mechanical properties with a TS of 47.9 MPa and a tensile modulus (TM) of 1792 MPa, possibly due to high yield formation of radicals to promote TMPTMA grafting during irradiation. The addition of CNC led to an additional improvement of the barrier properties, with a significant 25% reduction of water vapor permeability (WVP) of grafted films.

The Impact of Liver Graft Injury on Cancer Recurrence Posttransplantation.

Science.gov (United States)

Li, Chang-Xian; Man, Kwan; Lo, Chung-Mau

2017-11-01

Liver transplantation is the most effective treatment for selected patients with hepatocellular carcinoma. However, cancer recurrence, posttransplantation, remains to be the critical issue that affects the long-term outcome of hepatocellular carcinoma recipients. In addition to tumor biology itself, increasing evidence demonstrates that acute-phase liver graft injury is a result of hepatic ischemia reperfusion injury (which is an inevitable consequence during liver transplantation) and may promote cancer recurrence at late phase posttransplantation. The liver grafts from living donors, donors after cardiac death, and steatotic donors have been considered as promising sources of organs for liver transplantation and are associated with high incidence of liver graft injury. The acute-phase liver graft injury will trigger a series of inflammatory cascades, which may not only activate the cell signaling pathways regulating the tumor cell invasion and migration but also mobilize the circulating progenitor and immune cells to facilitate tumor recurrence and metastasis. The injured liver graft may also provide the favorable microenvironment for tumor cell growth, migration, and invasion through the disturbance of microcirculatory barrier function, induction of hypoxia and angiogenesis. This review aims to summarize the latest findings about the role and mechanisms of liver graft injury resulted from hepatic ischemia reperfusion injury on tumor recurrence posttransplantation, both in clinical and animal cohorts.

Submicroscopic pores grafted using the residual sites produced by swift heavy ions

International Nuclear Information System (INIS)

Mazzei, R.; Betz, N.; Bermudez, G. Garcia; Massa, G.; Smolko, E.

2005-01-01

To produce nuclear track membranes (NTM) with submicroscopic pores poly(vinylidene difluoride) (PVDF) foils were irradiated with Cl, Ag and Pb ions. Then they were chemically etched for different times and grafted with acrylic acid. The grafting yields were determined by weight measurements as a function of ion fluence, etching time and also analysed using Fourier transform infrared spectroscopy. Both measurements suggest that the acrylic acid was grafted on the pore wall of the NTM using the active sites left by the ion beam

Environmental application of radiation grafting

International Nuclear Information System (INIS)

Tamada, Masao

2007-01-01

Adsorbent having high selectivity against a certain metal ion was synthesized by means of radiation-induced graft polymerization for the purpose of environmental application. The resulting adsorbents were utilized for the removal of toxic metal from scallop waste and the collection of uranium from seawater. As a novel application of grafting, the biodegradability of poly-hydroxybutylate was controlled by grafting. The biodegradability could be depressed by the graft chain and then recovered by external stimuli such as thermal and chemical treatments. (author)

Graft union formation in Douglas-fir.

Science.gov (United States)

D.L. Copes

1969-01-01

Greenhouse-grown Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) graft unions were examined between 2 and 84 days after grafting. Room temperature was maintained at 60-70 F throughout the growing season. In most respects grafts of Douglas-fir followed development patterns previously reported for spruce and pine grafts, but specific differences...

Graft-copolymerization onto carbon black

International Nuclear Information System (INIS)

Nakase, Yoshiaki; Nishii, Masanobu; Kijima, Toshiyuki; Kato, Hiroshi.

1988-07-01

Radiation-induced graft copolymerization of vinyl monomer onto carbon black was performed. During the γ-ray- and electron beam-induced polymerization (In-source), or the electron beam post-polymerization, the graft-copolymerization behavior was affected by the kinds of both carbon blacks and monomers, i.e. the smaller the size of carbon black particles, the higher the apparent grafted fraction. Homopolymer in the grafted carbon black samples was washed out by the solvent of the polymer, and the extracted polymer seemed to be dimer or trimer of the used monomer. In the case of the post-polymerization with the pre-irradiation doses of 50 Mrad, homopolymer was hardly observed. The polymer sheets of plastics or rubbers with grafted carbon black had an electrical conductivity unalterable considerably by the heating cycles. The particles of grafted carbon black in the sheet might be kept much more at the surface layer within 100 nm depth than at the inner layer. (author)

FAS grafted superhydrophobic ceramic membrane

Science.gov (United States)

Lu, Jun; Yu, Yun; Zhou, Jianer; Song, Lixin; Hu, Xingfang; Larbot, Andre

2009-08-01

The hydrophobic properties of γ-Al 2O 3 membrane have been obtained by grafting fluoroalkylsilane (FAS) on the surface of the membrane. The following grafting parameters were studied: the eroding time of the original membrane, the grafting time, the concentration of FAS solution and the multiplicity of grafting. Hydrophobicity of the membranes was characterized by contact angle (CA) measurement. The thermogravimetric analysis (TGA) was used to investigate the weight loss process (25-800 °C) of the fluoroalkylsilane grafted on Al 2O 3 powders under different grafting conditions. The morphologies of the membranes modified under different parameters were examined by field emission scanning electron microscopy (FE-SEM) and the surface roughness (Ra) was measured using white light interferometers. A needle-like structure was observed on the membrane surface after modification, which causes the change of Ra. On the results above, we speculated a model to describe the reaction between FAS and γ-Al 2O 3 membrane surface as well as the formed surface morphology.

Radiation-induced grafting of TMPM onto polypropylene

International Nuclear Information System (INIS)

Wang Huiliang; Li Hong; Chen Wenxiu

1995-01-01

The gamma radiation-induced graft copolymerization of 2,2,6,6-tetramethyl-4-piperidinyl-methacrylate (TMPM), a very effective hindered amine light stabilizer (HALS), onto polypropylene was investigated by simultaneous- irradiation technique. The various synthesis conditions on the graft content was studied. It was found that benzene, CCl 4 and petroleum ether are more effective than other solvents, the percent grafting reached 7.1% for benzene. The percent grafting is higher when graft copolymerization is carried out in argon atmosphere than those in air. For all the grafting copolymerization carried out in benzene and CCl 4 , percent grafting increase linearly from 1 to 5 Mrad and beyond 5 Mrad, a tendency to level off appeared. At a constant dose, the percent grafting was found to be higher at high dose rate until 228 rad/s. Percent grafting also increased continuously with increasing monomer concentration up to 2.85 mol/L, but significant increase in grafting was observed only up to 1.14 mol/L

Salt-Induced Control of the Grafting Density in Poly(ethylene glycol) Brush Layers by a Grafting-to Approach

DEFF Research Database (Denmark)

Ortiz, Roberto; Olsen, Stefan; Thormann, Esben

2018-01-01

In this work, a method to obtain control of the grafting density during the formation of polymer brush layers by the grafting-to method of thiolated poly(ethylene glycol) onto gold is presented. The grafting density of the polymer chains was adjusted by adding Na2SO4 in concentrations between 0.......2 and 0.9 M to the aqueous polymer solution during the grafting process. The obtained grafting densities ranged from 0.26 to 1.60 chains nm-2, as determined by surface plasmon resonance. The kinetics of the grafting process were studied in situ by a quartz crystal microbalance with dissipation......, and a mushroom to brush conformational transition was observed when the polymer was grafted in the presence of Na2SO4. The transition from mushroom to brush was only observed for long periods of grafting, highlighting the importance of time to obtain high grafting densities. Finally, the prepared brush layer...

How to protect liver graft with nitric oxide

Institute of Scientific and Technical Information of China (English)

Hassen Ben Abdennebi; Mohamed Amine Zaoualí; Izabel Alfany-Fernandez; Donia Tabka; Joan Roselló-Catafau

2011-01-01

Organ preservation and ischemia reperfusion injury associated with liver transplantation play an important role in the induction of graft injury. One of the earliest events associated with the reperfusion injury is endothelial cell dysfunction. It is generally accepted that endothelial nitric oxide synthase (e-NOS) is cell-protective by mediating vasodilatation, whereas inducible nitric oxide synthase mediates liver graft injury after transplantation. We conducted a critical review of the literature evaluating the potential applications of regulating and promoting e-NOS activity in liver preservation and transplantation, showing the most current evidence to support the concept that enhanced bioavailability of NO derived from e-NOS is detrimental to ameliorate graft liver preservation, as well as preventing subsequent graft reperfusion injury. This review deals mainly with the beneficial effects of promoting "endogenous" pathways for NO generation, via e-NOS inducer drugs in cold preservation solution, surgical strategies such as ischemic preconditioning, and alternative "exogenous" pathways that focus on the enrichment of cold storage liquid with NO donors. Finally, we also provide a basic bench-to-bed side summary of the liver physiology and cell signalling mechanisms that account for explaining the e-NOS protective effects in liver preservation and transplantation.

Surface Modifications of Polymers Induced by Heavy Ions Grafting

Energy Technology Data Exchange (ETDEWEB)

Mazzei, R O; Lombardo, J; Camporotondi, D; Tadey, D; Bermudez, G G [National Atomic Energy Commission, Ezeiza Atomic Centre, Ezeiza (Argentina)

2012-09-15

Polymer surfaces are modified by the application of swift heavy ions etching and grafting procedures. The residual active sites produced by heavy ion beams, remaining after the etching process, were used to start the grafting process. In order to produce tracks on foils of poly(vinylidene fluoride) (PVDF) they were irradiated with {sup 208}Pb of 25.62 MeV/n or with 115 MeV Cl ions. Moreover, foils of polypropylene (PP) were irradiated with {sup 208}Pb of 25.62 MeV/n. Then, they were etched and grafted with N-isopropylacrylamide (NIPAAm) monomers or with acrylic acid (AAc) monomers, respectively. The replica method allowed the observation of the shape of the grafted tracks using transmission electron microscopy (TEM). In addition NIPAAm grafted foils were analyzed using Fourier transform infrared spectroscopy (FTIR). The sulfonation procedure (methodology previously described for perfluorated polymers) was applied on grafted PVDF. A new method is described to produce a thin layer of poly-acrylic-acid (membranes) that grows on the surface of PVDF foils implanted by an Ar{sup +} beam with energies between 30-150 keV. Different combinations of monomers in water solutions were used such as: acrylic acid (AAc); acrylic acid-glycidyl methacrylate (AAc-GMA); acrylic acid-styrene (AAc-S); acrylic acid-N-isopropyl acrylamide (AAc-NIPAAm) and acrylic acid-N-isopropyl acrylamide - glycidyl methacrylate (AAc-NIPAAm-GMA). The experimental results show that for particular values of: ion fluence and energy, AAc concentration, sulphuric acid and PVDF polymorphous (alpha or beta) a huge percentage of grafting was obtained. At certain point of the grafting process the development of the PolyAAc-Xmonomer produce a detachment from the irradiated substrate and continue its grafting outside it. This method produces a membrane that is an increased replica of the original implanted surface. Finally, PVDF films implanted by an Ar{sup +} beam with energies about 100 keV and a fluence of 10

Development of Highly Efficient Grafting Technique and Synthesis of Natural Polymer-Based Graft Adsorbent

Energy Technology Data Exchange (ETDEWEB)

Ueki, Y; Seko, N; Tamada, M [Japan Atomic Energy Agency, Quantum Beam Science Directorate, Takasaki (Japan)

2012-09-15

In the framework of the CRP, Japan has focused on the development of fibrous adsorbents for removal of toxic metal ions and recovery of significant metal ions from industrial wastewater and streaming water. Graft polymerization was carried out by using gamma irradiation facility and electron beam accelerator. Emulsion grafting is a novel topic for synthesis of metal ion adsorbents which are prepared from fibrous trunk polymers such as polyethylene fibre and biodegradable nonwoven fabrics. The emulsion grafting, where monomer micelles are dispersed in water in the presence of surfactant, is a highly efficient and economic grafting technique as compared to general organic solvent system. The resultant cotton-based adsorbent has high adsorption efficiency and high adsorption capacity for Hg, besides, it is biodegradable. Polylactic acid can also be used as a trunk material for the grafting. (author)

Nanostructure-Enabled and Macromolecule-Grafted Surfaces for Biomedical Applications

Directory of Open Access Journals (Sweden)

Madeline Small

2018-05-01

Full Text Available Advances in nanotechnology and nanomaterials have enabled the development of functional biomaterials with surface properties that reduce the rate of the device rejection in injectable and implantable biomaterials. In addition, the surface of biomaterials can be functionalized with macromolecules for stimuli-responsive purposes to improve the efficacy and effectiveness in drug release applications. Furthermore, macromolecule-grafted surfaces exhibit a hierarchical nanostructure that mimics nanotextured surfaces for the promotion of cellular responses in tissue engineering. Owing to these unique properties, this review focuses on the grafting of macromolecules on the surfaces of various biomaterials (e.g., films, fibers, hydrogels, and etc. to create nanostructure-enabled and macromolecule-grafted surfaces for biomedical applications, such as thrombosis prevention and wound healing. The macromolecule-modified surfaces can be treated as a functional device that either passively inhibits adverse effects from injectable and implantable devices or actively delivers biological agents that are locally based on proper stimulation. In this review, several methods are discussed to enable the surface of biomaterials to be used for further grafting of macromolecules. In addition, we review surface-modified films (coatings and fibers with respect to several biomedical applications. Our review provides a scientific update on the current achievements and future trends of nanostructure-enabled and macromolecule-grafted surfaces in biomedical applications.

Functionalization of nanochannels by radio-induced grafting polymerization on PET track-etched membranes

International Nuclear Information System (INIS)

Soto Espinoza, S.L.; Arbeitman, C.R.; Clochard, M.C.; Grasselli, M.

2014-01-01

The application of swift-heavy ion bombardment to polymers is a well-established technique to manufacture micro- and nanopores onto polymeric films to obtain porous membranes. A few years ago, it was realized that, during ion bombardment, the high energy deposition along the ion path through the polymer reached cylindrical damage regions corresponding to the core trace and the penumbra. After the etching procedure, there are still enough active sites left in the penumbra that can be used to initiate a polymerization process selectively inside the membrane pores. In this study, we report the grafting polymerization of glycidyl methacrylate onto etched PET foils to obtain functionalized nanochannels. Grafted polymers were labeled with a fluorescent tag and analyzed by different fluorescence techniques such as direct fluorescence, fluorescence microscopy and confocal microscopy. These techniques allowed identifying and quantifying the grafted regions on the polymeric foils. - Highlights: • Irradiated PET foils with swift-heavy ions were etched and grafted in a step-by-step process. • Grafting polymerization was performed on the remaining active sites after etching. • Track-etched PET membranes were fluorescently labeled by chemical functionalization. • Functionalized track-etched PET membranes were analyzed by fluorescence and confocal microscopy

Bracing can partially limit tibial rotation during stressful activities after anterior crucial ligament reconstruction with a hamstring graft.

Science.gov (United States)

Giotis, D; Paschos, N K; Zampeli, F; Pappas, E; Mitsionis, G; Georgoulis, A D

2016-09-01

Hamstring graft has substantial differences with BPTB graft regarding initial mechanical strength, healing sequence, and vascularization, which may imply that a different approach during rehabilitation period is required. The purpose of this study was to investigate the influence of knee bracing on tibial rotation in ACL-reconstructed patients with a hamstring autograft during high loading activities. The hypothesis was that there would be a decrease in tibial rotation in the ACL-reconstructed braced knee as compared to the unbraced knee. Twenty male patients having undergone unilateral ACL reconstruction with a semitendinosus/gracilis autograft were assessed. Kinematic data were collected with an eight-camera optoelectronic system during two stressful tasks: (1) descending from a stair and subsequent pivoting; and (2) landing from a platform and subsequent pivoting. In each patient, three different experimental conditions were evaluated: (A) wearing a prophylactic brace (braced condition); (B) wearing a patellofemoral brace (sleeved condition); (C) without brace (unbraced condition). The intact knee without brace served as a control. Tibial rotation was significantly lower in the intact knee compared to all three conditions of the ACL-reconstructed knee (P≤0.01 for both tasks). Presence of a brace or sleeve resulted in lower tibial rotation than in the unbraced condition (p=0.003 for descending/pivot and P=0.0004 for landing/pivot). The braced condition resulted in lower rotation than the sleeved condition for descending/pivoting (P=0.031) while no differences were found for landing/pivoting (P=0.230). Knee bracing limited the excessive tibial rotation during pivoting under high loading activities in ACL-reconstructed knees with a hamstring graft. This partial restoration of normal kinematics may have a potential beneficial effect in patients recovering from ACL reconstruction with a hamstring autograft. Level III, case-control therapeutic study. Copyright �

Effects of solvent polarity on mutual polypropylene grafting by electron beam irradiation

International Nuclear Information System (INIS)

Geraldo, A.B.C.; Moura, E.; Somessari, E.S.R.; Silveira, C.G.; Paes, H.A.; Souza, C.A.; Fernandes, W.; Manzoli, J.E.

2011-01-01

Complete text of publication follows. Copolymerization by grafting is a process largely known and the advantages of modifying polymers by radiation includes superimposition of properties related to the backbone and the grafted chains in the absence of an initiator. This process produces low byproduct levels, costs and hazards. Since polypropylene is applied in many industrial and commercial sectors, the grafting process is an alternative to improve some of its physical and chemical properties. The aim of this work was to verify the effect of distinct organic solvents on polypropylene grafting process by mutual irradiation applying absorbed doses from 30 kGy to 100 kGy at dose rates of 2.2 kGy/s and 22.4 kGy/s. All process were performed in atmosphere air presence. Styrene was the monomer grafted on polymer substrate and some non-polar and polar organic solvents, like toluene, xylene, acetone, methanol and its homologous, were used at distinct concentrations. The grafted samples were evaluated by degree of styrene grafting (gravimetric determination) and the Mid-FTIR spectrophotometry. As a general behavior, the degree of grafting increases when absorbed dose values increase in a specific solvent until a maximum dose value (50-70 kGy), after this, the degree of grafting decreases. Moreover, the grafting process have high yields when protic polar solvents are used. These results suggest the grafting process does not have dependence of substrate swelling, that is expected when a non-polar substrate and a non-polar media are in contact. The grafting, in this case, can be related to the free radical generation at protic polar solvents in a first step of process mechanism; these reactive specimens start the reaction on substrate surface to allow the accessibility of monomer species to active sites. Some reaction mechanisms are proposed.

Design of a Sapling Branch Grafting Robot

Directory of Open Access Journals (Sweden)

Qun Sun

2014-01-01

Full Text Available The automatic sapling grafting methods and grafting robot technologies are not comprehensively studied despite the fact that they are urgently required in practice. For this reason, a sapling grafting robot is developed to implement automatic grafting for saplings. The developed grafting robot includes clipping mechanism, moving mechanism, cutting mechanism, binding mechanism, and Arduino MCU based control system, which is capable of clipping, moving, positioning, cutting, grafting, and binding saplings. Experiments show that the stock cutting efficiency is 98.4%, the scion cutting efficiency is 98.9%, the grafting efficiency is 87.3%, and the binding efficiency is 68.9%.

Fat Grafting for Facial Filling and Regeneration.

Science.gov (United States)

Coleman, Sydney R; Katzel, Evan B

2015-07-01

Plastic surgeons have come to realize that fat grafting can rejuvenate an aging face by restoring or creating fullness. However, fat grafting does much more than simply add volume. Grafted fat can transform or repair the tissues into which it is placed. Historically, surgeons have hesitated to embrace the rejuvenating potential of fat grafting because of poor graft take, fat necrosis, and inconsistent outcomes. This article describes fat grafting techniques and practices to assist readers in successful harvesting, processing, and placement of fat for optimal graft retention and facial esthetic outcomes. Copyright © 2015 Elsevier Inc. All rights reserved.

Grafting: a technique to modify ion accumulation in horticultural crops

Directory of Open Access Journals (Sweden)

Muhammad Azher Nawaz

2016-10-01

Full Text Available Grafting is a centuries-old technique used in plants to obtain economic benefits. Grafting increases nutrient uptake and utilization efficiency in a number of plant species, including fruits, vegetables, and ornamentals. Selected rootstocks of the same species or close relatives are utilized in grafting. Rootstocks absorb more water and ions than self-rooted plants and transport these water and ions to the aboveground scion. Ion uptake is regulated by a complex communication mechanism between the scion and rootstock. Sugars, hormones, and miRNAs function as long-distance signaling molecules and regulate ion uptake and ion homeostasis by affecting the activity of ion transporters. This review summarizes available information on the effect of rootstock on nutrient uptake and utilization and the mechanisms involved. Information on specific nutrient-efficient rootstocks for different crops of commercial importance is also provided. Several other important approaches, such as interstocking (during double grafting, inarching, use of plant-growth-promoting rhizobacteria, use of arbuscular mycorrhizal fungi, use of plant growth substances (e.g., auxin and melatonin, and use of genetically engineered rootstocks and scions (transgrafting, are highlighted; these approaches can be combined with grafting to enhance nutrient uptake and utilization in commercially important plant species. Whether the rootstock and scion affect each other’s soil microbiota and their effect on the nutrient absorption of rootstocks remain largely unknown. Similarly, the physiological and molecular bases of grafting, crease formation, and incompatibility are not fully identified and require investigation. Grafting in horticultural crops can help reveal the basic biology of grafting, the reasons for incompatibility, sensing, and signaling of nutrients, ion uptake and transport, and the mechanism of heavy metal accumulation and restriction in rootstocks. Ion transporter and mi

[Surface grafting modification and stabilization of Kevlar fiber].

Science.gov (United States)

Zheng, Yu-ying; Fu, Ming-lian; Wang, Can-yao; Wang, Liang-en

2005-11-01

Chemical disposal was used to bring the activity group onto the surface of Kevlar fiber for the purpose of surface grafting modification. The interfacial constitution of the grafting of toluene-2,4-diisocyanate (TDI) onto Kevlar fiber was determined by Fourier transform infrared spectroscopy. In the mean time, hexyl-lactam stabilization and poly-glycol (400, PEG) stabilization on the grafted product were also studied. The effects of different nTDI:nPEG ratios on the production's interfacial constitution was analysed. It is concluded that the stabilization took place on the surface. The intensity of the bands relented at about 3300 cm(-1) and was reinforced at about 1700-1720 cm(-1) when the ratio of nTDI:nPEG = 1:3, but when the ratio is 1:1 and 1:2, the bands at about 3 300 and 1700-1720 cm(-1) are almost the same.

Determination of grafting conversion degree in PS/PS-graft-POSS/POSS hybrid nanocomposites obtained through reactive processing

International Nuclear Information System (INIS)

Bianchi, Otavio; Repenning, Gustavo B.; Mauler, Raquel S.; Oliveira, Ricardo V.B.; Canto, Leonardo B.

2011-01-01

Hybrid nanocomposites of polystyrene (PS) and polyhedral oligomeric silsesquioxanes (POSS) - PS/PS-graft-POSS/POSS - with different grafting degrees were prepared by reactive melt processing using dicumyl peroxide (DCP) as initiator in the presence or absence of styrene monomer as radical transfer agent. Gel permeation chromatography (GPC) using triple-detector and proton nuclear magnetic resonance (NMR 1 H) analyses were used together to determine the conversion degree of PS-graft-POSS as a function of the reactive processing conditions adopted. GPC was employed to evaluate the effects of grafting (PS-graft-POSS) and PS chains degradation (β scission) that occur simultaneously during processing on the variation of average molecular masses and distributions for each PS/POSS sample. PS/POSS systems processed with styrene showed higher weight average molecular weights (M w ) and lower polydispersity indexes (M w /M n ), as a result of higher grafting (PS-graft-POSS) conversion (28-40%) and lower PS chain degradation level, as compared to PS/POSS systems processed without styrene in which the degree of grafting conversion was around 25-28%. (author)

One Year Outcomes of 101 BeGraft Stent Grafts used as Bridging Stents in Fenestrated Endovascular Repairs.

Science.gov (United States)

Spear, Rafaelle; Sobocinski, Jonathan; Hertault, Adrien; Delloye, Matthieu; Azzauiu, Richard; Fabre, Dominique; Haulon, Stéphan

2018-04-01

To evaluate the outcomes of the second generation BeGraft balloon expandable covered stent Graft System (Bentley InnoMed, Hechingen, Germany) implanted as bridging stent grafts during fenestrated endovascular aortic repair (FEVAR) of complex aneurysms. This was a single centre prospective study including all consecutive patients treated by FEVAR performed with second generation BeGraft stent grafts as bridging stents. Demographics of patients, diameter and length of the bridging stent grafts, technical success, re-interventions, occlusions, post-operative events, and imaging (Cone Beam CT and/or CT scan, and contrast enhanced ultrasound) were prospectively collected in an electronic database. Duplex ultrasound was performed before discharge and at 6 month follow-up. At 1 year, patients were evaluated clinically and by imaging (CT and ultrasound). Between November 2015 and September 2016, 39 consecutive patients (one woman) were treated with custom made fenestrated endografts (2-5 fenestrations) for complex aneurysms or type 1 endoleak after EVAR, using a variety of bridging stents including the BeGraft. All 101 BeGraft stent grafts were successfully delivered and deployed. There was no in hospital mortality. Early fenestration patency rate was 99% (96/97); the sole target vessel post-operative occlusion was secondary to a dissection of the renal artery distal to the stent. Complementary stenting was unsuccessful in recovering renal artery patency; bilateral renal stent occlusion was observed in the same patient on a CT scan performed 2 months after the procedure. He required post-operative dialysis. No additional renal impairment was observed. During follow-up (median 13 months [11-15]), all fenestrations stented with BeGraft stent grafts remained patent (95/97, 98%). One type 1b endoleak was detected and treated (2.6%). BeGraft stent grafts used as bridging stents during FEVAR are associated with favourable outcomes at 1 year follow-up. Long-term follow-up is

A study on the morphology of polystyrene-grafted poly(ethylene-alt-tetrafluoroethylene) (ETFE) films prepared using a simultaneous radiation grafting method

International Nuclear Information System (INIS)

Song, Ju-Myung; Ko, Beom-Seok; Sohn, Joon-Yong; Nho, Young Chang; Shin, Junhwa

2014-01-01

The morphology of polystyrene-grafted poly(ethylene-alt-tetrafluoroethylene) (ETFE) films prepared using a simultaneous radiation grafting method was investigated using DMA, DSC, XRD, and SAXS instruments. The DMA study indicates that the ETFE amorphous phase and PS amorphous phase are mixed well in the PS-grafted ETFE films while the ETFE crystalline phase and the PS amorphous phase are separated, suggesting that the PS chains are grafted mainly on the ETFE amorphous regions. The DSC and XRD data showed that the natural crystalline structures of ETFE in the grafted ETFE films are not affected by the degree of grafting. The SAXS profiles displayed that the inter-crystalline distance of the ETFE films increases with an increasing degree of grafting, which further implies that the PS graft chains formed by the simultaneous irradiation has a significant impact on the amorphous morphology of the resulting grafted ETFE film. Thus, these results indicate that the styrene monomers are mainly grafted on the ETFE amorphous regions during the simultaneous radiation grafting process. - Highlights: • PS-grafted ETFE films were prepared by a simultaneous radiation grafting method was investigated. • The natural crystalline structures of grafted ETFE films are not affect by the degree of grafting. • The inter-crystalline distance of the ETFE films increase with increasing degree of grafting. • The styrene monomers are mainly grafted on the ETFE amorphous regions during a simultaneous radiation grafting using gamma-ray

Acrylic acid grafted PDMS preliminary activated by Ar{sup +}beam plasma and cell observation

Energy Technology Data Exchange (ETDEWEB)

Kostadinova, A.; Zaekov, N. [Institute of Biophysics, BAS, Sofia (Bulgaria); Keranov, I. [Department of Polymer Engineering, University of Chemical Technology and Metallurgy (UCTM), Sofia (Bulgaria)

2007-07-01

Plasma based Ar{sup +} beam performed in RF (13.56 MHz) low-pressure (200 mTorr) glow discharge (at 100 W, 1200 W and 2500 W) with a serial capacitance was employed for surface modification of poly(dimethylsiloxane) (PDMS) aimed at improvement of its interactions with living cells. The presence of a serial capacitance ensures arise of an ion-flow inside the plasma volume directed toward the treated sample and the vary of the discharge power ensures varied density of the ion-flow The initial adhesion of human fibroblast cells was studied on the described above plasma based Ar{sup +}beam modified and acrylic acid (AA) grafted or not fibronectin (FN) pre-coated or ba resurfaces. The cell response seem sto be related with the peculiar structure and wettability of the modified PDMS surface layer after plasma based Ar{sup +} beam treatment followed or not by AA grafting. Key words: Biomaterials; Surface treatment of PDMS; Plasma based Ar{sup +} beam; Acrylic acid grafting; Fibroblast cells.

Effects of grafting with pumpkin rootstock on carbohydrate metabolism in cucumber seedlings under Ca(NO3)2 stress.

Science.gov (United States)

Xing, Wen-wen; Li, Lin; Gao, Pan; Li, He; Shao, Qiao-sai; Shu, Sheng; Sun, Jin; Guo, Shi-rong

2015-02-01

This study investigated the effects of grafting on the carbohydrate status and the enzymes of carbohydrate metabolism in self-grafted and grafted cucumber seedlings using the salt-tolerant pumpkin rootstock 'Qingzhen 1' (Cucurbita maxima × Cucurbita moschata) under 80 mM Ca(NO3)2 stress for 6 d. The growth of self-grafted seedlings was significantly inhibited after the treatment of Ca(NO3)2 stress, whereas the inhibition of growth was alleviated in pumpkin rootstock-grafted seedlings. Ca(NO3)2 stress increased the contents of the total soluble sugar, sucrose and fructose, but decreased the starch content in rootstock-grafted leaves. However, compared with self-grafted plants, rootstock-grafted seedlings were observed with a higher content of sucrose and total soluble sugar (TSS) under salt stress. Rootstock-grafted seedlings exhibited higher activities of acid invertase (AI), neutral invertase (NI) and phosphate sucrose synthase (SPS) of sucrose metabolism in leaves than that of self-grafted seedlings under salinity. Moreover, the activities of fructokinase (FK), hexokinase (HK), phosphofructokinase (PFK) and pyruvate kinase (PK) of glycolysis were maintained at a higher level in leaves of rootstock-grafted seedlings after Ca(NO3)2 stress. Additionally, rootstock-grafting decrease the high percentage enhancement of key enzymes gene expression in glycolysis in the scion leaves of cucumber seedlings induced by salt stress. These results suggest that the rootstock-grafting improved salt tolerance, which might play a role in elevated sucrose metabolism and a glycolytic pathway regulated by the pumpkin rootstock. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Separation of several alcohol-benzene mixtures by pervaporation through styrene graft polyethylene membranes

International Nuclear Information System (INIS)

Murata, Kenichi

1989-01-01

The permeation of pure liquids, such as methanol, ethanol, 1-propanol, 2-propanol and benzene, and the permeability and selectivity of 50 vol% binary mixtures of these alcohols and benzene were investigated by pervaporation technique. The used membranes (21%, 40%, and 72% graftings) were obtained by graft polymerization of styrene to polyethylene film (thickness 10 μm) by γ-radiation. The permeation rates of each of these alcohols and benzene were measured by pervaporation through the graft membranes. Those of these alcohols were very small as well as those through the original membrane. On the other hand, the permeabilities for benzene through the graft membranes were larger than that through the original membrane. The temperature dependence of the permeation rate for benzene was expressed by Arrhenius-type relationships, and the apparent activation energies were calculated to be 10.7 (21%), 10.2 (40%) and 10.0 (72%) kcal/mol. In the permeation of 50 vol% several alcohol-benzene mixtures, the permeabilities through the graft membranes were also larger than that through the original membrane, and increased with the grafting. The temperature dependence of the permeation for these mixtures was showed by Arrhenius relationships, and the apparent activation energies were calculated to be in the range of 8.4∼11.0 kcal/mol. The separation factors of the graft membranes calculated from composition of the permeates were always smaller than that of the original membrane, but became larger with increase of molecular volume of alcohol in alcohol-benzene mixtures. (author)

FAS grafted superhydrophobic ceramic membrane

Energy Technology Data Exchange (ETDEWEB)

Lu Jun [School of Material Science and Engineering, Jingdezhen Ceramic Institute, 333001 Jingdezhen (China); Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, CAS, 1295 DingXi Road, Shanghai 200050 (China); Yu Yun, E-mail: yunyush@mail.sic.ac.cn [Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, CAS, 1295 DingXi Road, Shanghai 200050 (China); Zhou Jianer [School of Material Science and Engineering, Jingdezhen Ceramic Institute, 333001 Jingdezhen (China); Song Lixin; Hu Xingfang [Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, CAS, 1295 DingXi Road, Shanghai 200050 (China); Larbot, Andre [Institut Europeen des Membranes, UMR 5635-CNRS, ENSCM, UMII, 1919 Route de Mende 34293, Montpellier Cedex 5 (France)

2009-08-30

The hydrophobic properties of {gamma}-Al{sub 2}O{sub 3} membrane have been obtained by grafting fluoroalkylsilane (FAS) on the surface of the membrane. The following grafting parameters were studied: the eroding time of the original membrane, the grafting time, the concentration of FAS solution and the multiplicity of grafting. Hydrophobicity of the membranes was characterized by contact angle (CA) measurement. The thermogravimetric analysis (TGA) was used to investigate the weight loss process (25-800 deg. C) of the fluoroalkylsilane grafted on Al{sub 2}O{sub 3} powders under different grafting conditions. The morphologies of the membranes modified under different parameters were examined by field emission scanning electron microscopy (FE-SEM) and the surface roughness (Ra) was measured using white light interferometers. A needle-like structure was observed on the membrane surface after modification, which causes the change of Ra. On the results above, we speculated a model to describe the reaction between FAS and {gamma}-Al{sub 2}O{sub 3} membrane surface as well as the formed surface morphology.

Postoperative radiographic evaluation of vascularized fibular grafts

International Nuclear Information System (INIS)

Manaster, B.J.; Coleman, D.A.; Bell, D.A.

1989-01-01

This paper reports on thirty-five patients with free vascularized fibular grafts examined postoperatively with plain radiography. Early graft incorporation is seen as a fuzziness of the cortex at the site of its insertion into the host bone. Causes of failure in grafting for bone defects include graft fracture, hardware failure, and infection. A high percentage of complications or at least delayed unions occurred when vascularized fibular grafts were used to fill defects in the lower extremity. Conversely, upper extremity defects bridged by vascularized grafts heal quickly and hypertrophy. Vascularized grafts placed in the femoral head and neck for a vascular necrosis incorporate early on their superior aspect. The osseous tunnel in which they are placed is normally wider than the graft and often becomes sclerotic; this appearance does not represent nonunion

Arterial grafts balance survival between incomplete and complete revascularization: a series of 1000 consecutive coronary artery bypass graft patients with 98% arterial grafts.

Science.gov (United States)

Kieser, Teresa M; Curran, Helen J; Rose, M Sarah; Norris, Colleen M; Graham, Michelle M

2014-01-01

Coronary artery bypass grafting (CABG) with incomplete revascularization (ICR) is thought to decrease survival. We studied the survival of patients with ICR undergoing total arterial grafting. In a consecutive series of all-comer 1000 patients with isolated CABG, operative and midterm survival were assessed for patients undergoing complete versus ICR, with odds ratios and hazard ratios, adjusted for European System for Cardiac Operative Risk Evaluation category, CABG urgency, age, and comorbidities. In this series of 1000 patients with 98% arterial grafts (2922 arterial, 59 vein grafts), 73% of patients with multivessel disease received bilateral internal mammary artery grafts. ICR occurred in 140 patients (14%). Operative mortality was 3.8% overall, 8.6% for patients with ICR, and 3.2% for patients with complete revascularization (P = .008). For operative mortality using multivariable logistic regression, after controlling for European System for Cardiac Operative Risk Evaluation category (P System for Cardiac Operative Risk Evaluation category (P reserved.

Emerging concepts in liver graft preservation

Science.gov (United States)

Bejaoui, Mohamed; Pantazi, Eirini; Folch-Puy, Emma; Baptista, Pedro M; García-Gil, Agustín; Adam, René; Roselló-Catafau, Joan

2015-01-01

The urgent need to expand the donor pool in order to attend to the growing demand for liver transplantation has obliged physicians to consider the use of suboptimal liver grafts and also to redefine the preservation strategies. This review examines the different methods of liver graft preservation, focusing on the latest advances in both static cold storage and machine perfusion (MP). The new strategies for static cold storage are mainly designed to increase the fatty liver graft preservation via the supplementation of commercial organ preservation solutions with additives. In this paper we stress the importance of carrying out effective graft washout after static cold preservation, and present a detailed discussion of the future perspectives for dynamic graft preservation using MP at different temperatures (hypothermia at 4 °C, normothermia at 37 °C and subnormothermia at 20 °C-25 °C). Finally, we highlight some emerging applications of regenerative medicine in liver graft preservation. In conclusion, this review discusses the “state of the art” and future perspectives in static and dynamic liver graft preservation in order to improve graft viability. PMID:25593455

Enrichment of autologous fat grafts with ex-vivo expanded adipose tissue-derived stem cells for graft survival

DEFF Research Database (Denmark)

Kølle, Stig-Frederik Trojahn; Fischer-Nielsen, Anne; Mathiasen, Anders Bruun

2013-01-01

Autologous fat grafting is increasingly used in reconstructive surgery. However, resorption rates ranging from 25% to 80% have been reported. Therefore, methods to increase graft viability are needed. Here, we report the results of a triple-blind, placebo-controlled trial to compare the survival ...... of fat grafts enriched with autologous adipose-derived stem cells (ASCs) versus non-enriched fat grafts....

Radiolytic synthesis and electrocatalytic activity of bimetallic nanoaggregates grafted upon various electrodes

International Nuclear Information System (INIS)

Amblard, J.; Belloni, J.; Platzer, O.

1991-01-01

We show how to utilize the radiolytic pathway for grafting metal nanoaggregates upon anodes or cathodes involved in the chlorine-soda process, thus enhancing their electrochemical behaviour. In both cases important overpotentials are usually measured on unmodified electrodes. The electrocatalytic efficiency of bimetallic nanoparticles (such as Pt-Ru and Ni-Ru), once grafted onto bulk metal electrodes (Ti or Ni), has been investigated by measuring the overpotential for chlorine or hydrogen evolution, respectively. Experimental conditions are similar to those of the industrial process. A synergistic effect is shown when Pt and Ru are alloyed in a 2: 1 atomic ratio. Then the chlorine overpotential is minimum. Conversely, there is no synergy between Ni and Ru, although a minimum amount of Ru in Ru-Ni (50% atomic) ensures a very low hydrogen overpotential [fr

Intraoperative echocardiographic imaging of coronary arteries and graft anastomoses during coronary artery bypass grafting without cardiopulmonary bypass.

Science.gov (United States)

Suematsu, Y; Takamoto, S; Ohtsuka, T

2001-12-01

No accepted approach exists for the intraoperative evaluation of the quality of coronary arteries and the technical adequacy of graft anastomoses during coronary artery bypass grafting without cardiopulmonary bypass. We assessed the accuracy of high-frequency epicardial echocardiography and power Doppler imaging in evaluating coronary arteries during coronary artery bypass grafting without cardiopulmonary bypass. To validate measurements of coronary arteries and graft anastomoses by high-frequency epicardial echocardiography and power Doppler imaging, we compared luminal diameters determined by these methods with diameters determined histologically in a study of off-pump coronary artery bypass grafting in 20 dogs. Technical errors were deliberately created in 10 grafts (stenosis group). The results of these animal validation studies showed that the maximum luminal diameters of coronary arteries and graft anastomoses measured by high-frequency epicardial echocardiography (HEE) and power Doppler imaging (PDI) correlated well with the histologic measurements: HEE = 1.027 x Histologic measurements + 0.005 (P anastomoses were examined intraoperatively by high-frequency epicardial echocardiography and power Doppler imaging, and luminal diameters determined by power Doppler imaging were compared with those determined by postoperative coronary angiography. The results demonstrated that graft anastomosis by power Doppler imaging correlated well with the angiographic measurements: PDI = 1.018 x Angiographic measurements - 0.106 (P anastomoses and can detect technical errors and inadequacies during coronary artery bypass grafting without cardiopulmonary bypass.

Multiple arterial grafts in coronary artery bypass grafting, Sohag University Hospital's initial experience

Directory of Open Access Journals (Sweden)

A.A.A. Elsayed

2017-12-01

Conclusions: Using multiple arterial grafts did not add a significant risk or time to the classic CABG. With accumulating evidence about better patency rate in arterial grafts, MAR is recommended especially in younger patients undergoing CABG.

Corona-induced graft polymerization for surface modification of porous polyethersulfone membranes

International Nuclear Information System (INIS)

Zhu Liping; Zhu Baoku; Xu Li; Feng Yongxiang; Liu Fu; Xu Youyi

2007-01-01

Graft polymerization of acrylic acid (AA) onto porous polyethersulfone (PES) membrane surfaces was developed using corona discharge in atmospheric ambience as an activation process followed by polymerization of AA in aqueous solution. The effects of the corona parameters and graft polymerization conditions on grafting yield (GY) of AA were investigated. The grafting of AA on the PES membranes was confirmed by ATR-FTIR and X-ray photoelectron spectroscopy (XPS) analysis. Porosimetry measurements indicate the average pore diameters and porosities of the modified membranes decrease with the increase of the GY. The hydrophilicity and surface wetting properties of the original and modified membranes were evaluated by observing the dynamic changes of water contact angles. It is found that the grafting of AA occurs not only on the membrane surfaces, but also on the pore walls of the cells inside the membrane. The permeability experiments of protein solution reveal that the grafting of PAA endows the modified membranes with enhanced fluxes and anti-fouling properties. The optimized GY of AA is in the range of 150-200 μg/cm 2 . In addition, the tensile experiments show the corona discharge treatment with the power lower than 150 W yields little damage to the mechanical strength of the membranes

Radiation-induced grafting from binary mixture of monomers onto cellulose acetate film and the characterization of the graft copolymer

International Nuclear Information System (INIS)

Bhattacharyya, S.N.; Maldas, D.

1984-01-01

Binary mixtures of styrene and acrylamide in methanol-water were grafted onto cellulose acetate films by taking recourse to preirradiation grafting technique. The extent of total grafting was determined from the measured weight increase. The percent acrylamide residue in the graft copolymer was calculated from the observed nitrogen content but the polystyrene residue in the grafted sample was determined by IR spectral studies. When the specific permeability of water vapour through the grafted films is measured, it is observed that the specific permeability increases with the increase of grafting of acrylamide in all humidities, but in case of styrene which is a nonpolar molecule the permeability is found to show a reversed order. In the case of mixed graft the permeability pattern pertains to that when both styrene and acrylamide have their effective roles to play. (author)

Osseointegration of dental implants in 3D-printed synthetic onlay grafts customized according to bone metabolic activity in recipient site.

Science.gov (United States)

Tamimi, Faleh; Torres, Jesus; Al-Abedalla, Khadijeh; Lopez-Cabarcos, Enrique; Alkhraisat, Mohammad H; Bassett, David C; Gbureck, Uwe; Barralet, Jake E

2014-07-01

Onlay grafts made of monolithic microporous monetite bioresorbable bioceramics have the capacity to conduct bone augmentation. However, there is heterogeneity in the graft behaviour in vivo that seems to correlate with the host anatomy. In this study, we sought to investigate the metabolic activity of the regenerated bone in monolithic monetite onlays by using positron emission tomography-computed tomography (PET-CT) in rats. This information was used to optimize the design of monetite onlays with different macroporous architecture that were then fabricated using a 3D-printing technique. In vivo, bone augmentation was attempted with these customized onlays in rabbits. PET-CT findings demonstrated that bone metabolism in the calvarial bone showed higher activity in the inferior and lateral areas of the onlays. Histological observations revealed higher bone volume (up to 47%), less heterogeneity and more implant osseointegration (up to 38%) in the augmented bone with the customized monetite onlays. Our results demonstrated for the first time that it is possible to achieve osseointegration of dental implants in bone augmented with 3D-printed synthetic onlays. It was also observed that designing the macropore geometry according to the bone metabolic activity was a key parameter in increasing the volume of bone augmented within monetite onlays. Copyright © 2014 Elsevier Ltd. All rights reserved.

C1-esterase inhibitor protects against early vein graft remodeling under arterial blood pressure.

Science.gov (United States)

Krijnen, Paul A J; Kupreishvili, Koba; de Vries, Margreet R; Schepers, Abbey; Stooker, Wim; Vonk, Alexander B A; Eijsman, Leon; Van Hinsbergh, Victor W M; Zeerleder, Sacha; Wouters, Diana; van Ham, Marieke; Quax, Paul H A; Niessen, Hans W M

2012-01-01

Arterial pressure induced vein graft injury can result in endothelial loss, accelerated atherosclerosis and vein graft failure. Inflammation, including complement activation, is assumed to play a pivotal role herein. Here, we analyzed the effects of C1-esterase inhibitor (C1inh) on early vein graft remodeling. Human saphenous vein graft segments (n=8) were perfused in vitro with autologous blood either supplemented or not with purified human C1inh at arterial pressure for 6h. The vein segments and perfusion blood were analyzed for cell damage and complement activation. In addition, the effect of purified C1inh on vein graft remodeling was analyzed in vivo in atherosclerotic C57Bl6/ApoE3 Leiden mice, wherein donor caval veins were interpositioned in the common carotid artery. Application of C1inh in the in vitro perfusion model resulted in significantly higher blood levels and significantly more depositions of C1inh in the vein wall. This coincided with a significant reduction in endothelial loss and deposition of C3d and C4d in the vein wall, especially in the circular layer, compared to vein segments perfused without supplemented C1inh. Administration of purified C1inh significantly inhibited vein graft intimal thickening in vivo in atherosclerotic C57Bl6/ApoE3 Leiden mice, wherein donor caval veins were interpositioned in the common carotid artery. C1inh significantly protects against early vein graft remodeling, including loss of endothelium and intimal thickening. These data suggest that it may be worth considering its use in patients undergoing coronary artery bypass grafting. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Comparison of mesencephalic free-floating tissue culture grafts and cell suspension grafts in the 6-hydroxydopamine-lesioned rat

DEFF Research Database (Denmark)

Meyer, Morten; Widmer, H R; Wagner, B

1998-01-01

of grafted dopaminergic neurons and to correlate that with the behavioral effects. Additional cultures and acutely prepared explants were also fixed and stored for histological investigation in order to estimate the loss of dopaminergic neurons in culture and after transplantation. Similar behavioral...... numbers of TH-immunoreactive (TH-ir) neurons in grafts of cultured tissue (775 +/- 98, mean +/- SEM) and grafts of fresh, dissociated cell suspension (806 +/- 105, mean +/- SEM). Cell counts in fresh explants, 7-day-old cultures, and grafted cultures revealed a 68.2% loss of TH-ir cells 7 days after......Ventral mesencephalon (VM) of fetal rat and human origin grown as free-floating roller-tube (FFRT) cultures can survive subsequent grafting to the adult rat striatum. To further explore the functional efficacy of such grafts, embryonic day 13 ventral mesencephalic tissue was grafted either after 7...

Radiation grafting on natural films

International Nuclear Information System (INIS)

Lacroix, M.; Khan, R.; Senna, M.; Sharmin, N.; Salmieri, S.; Safrany, A.

2014-01-01

Different methods of polymer grafting using gamma irradiation are reported in the present study for the preparation of newly functionalized biodegradable films, and some important properties related to their mechanical and barrier properties are described. Biodegradable films composed of zein and poly(vinyl alcohol) (PVA) were gamma-irradiated in presence of different ratios of acrylic acid (AAc) monomer for compatibilization purpose. Resulting grafted films (zein/PVA-g-AAc) had their puncture strength (PS=37–40 N mm −1 ) and puncture deformation (PD=6.5–9.8 mm) improved for 30% and 50% PVA in blend, with 5% AAc under 20 kGy. Methylcellulose (MC)-based films were irradiated in the presence of 2-hydroxyethyl methacrylate (HEMA) or silane, in order to determine the effect of monomer grafting on the mechanical properties of films. It was found that grafted films (MC-g-HEMA and MC-g-silane) using 35% monomer performed higher mechanical properties with PS values of 282–296 N mm −1 and PD of 5.0–5.5 mm under 10 kGy. Compatibilized polycaprolactone (PCL)/chitosan composites were developed via grafting silane in chitosan films. Resulting trilayer grafted composite film (PCL/chitosan-g-silane/PCL) presented superior tensile strength (TS=22 MPa) via possible improvement of interfacial adhesion (PCL/chitosan) when using 25% silane under 10 kGy. Finally, MC-based films containing crystalline nanocellulose (CNC) as a filling agent were prepared and irradiated in presence of trimethylolpropane trimethacrylate (TMPTMA) as a grafted plasticizer. Grafted films (MC-g-TMPTMA) presented superior mechanical properties with a TS of 47.9 MPa and a tensile modulus (TM) of 1792 MPa, possibly due to high yield formation of radicals to promote TMPTMA grafting during irradiation. The addition of CNC led to an additional improvement of the barrier properties, with a significant 25% reduction of water vapor permeability (WVP) of grafted films. - Highlights: • Irradiation of zein

Preparation of poly(vinylbenzyl chloride)-grafted PFA film by a simultaneous irradiation grafting method

International Nuclear Information System (INIS)

Fei, Geng; Shin, Jun Hwa; Nho, Young Chang; Lee, Youn Sik

2009-01-01

In this study, PFA-g-PVBC films were prepared by a radiation grafting of vinylbenzyl chloride (VBC) monomer onto poly(tetrafluoroethylene-co-perfluoro propyl vinyl ether) (PFA) films by simultaneous irradiation method. IR, TGA, and SEM-EDX instruments were utilized to confirm the successful preparation of the grafted film. The effects of several irradiation conditions, including the dose, VBC concentration, and film thickness on the degree of grafting of PFA-g-PVBC film were investigated

Interventions in Infrainguinal Bypass Grafts

International Nuclear Information System (INIS)

Mueller-Huelsbeck, S.; Order, B.-M.; Jahnke, T.

2006-01-01

The interventional radiologist plays an important role in the detection and prevention of infrainguinal bypass failure. Early detection and evaluation of flow-limiting lesions effectively preserve graft (venous bypass and polyester or expanded polytetrafluoroethylene bypass) patency by identifying stenoses before occlusion occurs. Delay in treatment of the at-risk graft may result in graft failure and a reduced chance of successful revascularization. For this reason, surveillance protocols form an important part of follow-up after infrainguinal bypass surgery. As well as having an understanding of the application of imaging techniques including ultrasound, MR angiography, CT angiography and digital subtraction angiography, the interventional radiologist should have detailed knowledge of the minimally invasive therapeutic options. Percutaneous transluminal angioplasty (PTA), or alternatively cutting balloon angioplasty, is the interventional treatment of choice in prevention of graft failure and occlusion. Further alternatives include metallic stent placement, fibrinolysis, and mechanical thrombectomy. Primary assisted patency rates following PTA can be up to 65% at 5 years. When the endovascular approach is unsuccessful, these therapeutic options are complemented by surgical procedures including vein patch revision, jump grafting, or placement of a new graft

Effect of cationic grafted copolymer structure on the encapsulation of bovine serum albumin

International Nuclear Information System (INIS)

Flynn, Nicholas; Topal, Ç. Özge; Hikkaduwa Koralege, Rangika S.; Hartson, Steve; Ranjan, Ashish; Liu, Jing; Pope, Carey; Ramsey, Joshua D.

2016-01-01

The aim of the present study was to evaluate a library of poly-L-lysine (PLL)-graft (g)-polyethylene glycol (PEG) copolymers for the ability to encapsulate effectively a model protein, bovine serum albumin (BSA), and to characterize the stability and protein function of the resulting nanoparticle. A library of nine grafted copolymers was produced by varying PLL molecular weight and PEG grafting ratio. Electrostatic self-assembly of the protein and the grafted copolymer drove encapsulation. The formation of protein/polymer nanoparticles with a core/shell structure was confirmed using PAGE, dynamic light scattering, and electron microscopy. Encapsulation of the BSA into nanoparticles was strongly dependent on the copolymer-to-protein mass ratio, PEG grafting ratio, and PLL molecular weight. A copolymer-to-protein mass ratio of 7:1 and higher was generally required for high levels of encapsulation, and under these conditions, no loss of protein activity was observed. Copolymer characteristics also influenced nanoparticle resistance to polyanions and protease degradation. The results indicate that a copolymer of 15–30 kDa PLL, with a PEG grafting ratio of 10:1, is most promising for protein delivery. - Highlights: • A 4–70 kDa range of PLL-g-PEG copolymers was able to encapsulate BSA into NPs. • Encapsulation of BSA by PLL-g-PEG not only retained but increased esterolytic activity. • NPs were stable against protease degradation and polyanion dissociation.

Effect of cationic grafted copolymer structure on the encapsulation of bovine serum albumin

Energy Technology Data Exchange (ETDEWEB)

Flynn, Nicholas [School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078 (United States); Topal, Ç. Özge [School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, OK 74078 (United States); Hikkaduwa Koralege, Rangika S. [School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078 (United States); Hartson, Steve [Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078 (United States); Ranjan, Ashish; Liu, Jing; Pope, Carey [Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078 (United States); Ramsey, Joshua D., E-mail: josh.ramsey@okstate.edu [School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078 (United States)

2016-05-01

The aim of the present study was to evaluate a library of poly-L-lysine (PLL)-graft (g)-polyethylene glycol (PEG) copolymers for the ability to encapsulate effectively a model protein, bovine serum albumin (BSA), and to characterize the stability and protein function of the resulting nanoparticle. A library of nine grafted copolymers was produced by varying PLL molecular weight and PEG grafting ratio. Electrostatic self-assembly of the protein and the grafted copolymer drove encapsulation. The formation of protein/polymer nanoparticles with a core/shell structure was confirmed using PAGE, dynamic light scattering, and electron microscopy. Encapsulation of the BSA into nanoparticles was strongly dependent on the copolymer-to-protein mass ratio, PEG grafting ratio, and PLL molecular weight. A copolymer-to-protein mass ratio of 7:1 and higher was generally required for high levels of encapsulation, and under these conditions, no loss of protein activity was observed. Copolymer characteristics also influenced nanoparticle resistance to polyanions and protease degradation. The results indicate that a copolymer of 15–30 kDa PLL, with a PEG grafting ratio of 10:1, is most promising for protein delivery. - Highlights: • A 4–70 kDa range of PLL-g-PEG copolymers was able to encapsulate BSA into NPs. • Encapsulation of BSA by PLL-g-PEG not only retained but increased esterolytic activity. • NPs were stable against protease degradation and polyanion dissociation.

Reduction of indium-111 platelet deposition on Dacron vascular grafts in humans by aspirin plus dipyridamole

International Nuclear Information System (INIS)

Stratton, J.R.; Ritchie, J.L.

1986-01-01

Aspirin plus dipyridamole reduces platelet accumulation on short-term Dacron vascular grafts in man. To determine whether drug inhibition of platelet deposition is sustained on older grafts, we studied 18 men aged 41 to 87 years who had Dacron aortic bifurcation grafts in place a mean of 43.4 months (range 9.8 to 121.0) before and during short-term therapy with aspirin (325 mg tid) plus dipyridamole (75 mg tid). During both the baseline and drug studies, indium-111 ( 111 In) platelet deposition was quantitated by two techniques, standard planar imaging performed at 24, 48, and 72 hr after injection of platelets and single photon emission computed tomographic imaging performed at 24 and 72 hr after injection. All analyses were performed in a blinded fashion. On both the planar and tomographic images, platelet accumulation on the graft was quantitated by a graft/blood ratio that compared activity in the graft to simultaneously collected whole blood 111 In platelet activity. Aspirin plus dipyridamole reduced the tomographic graft/blood ratio at 24 hr (20.6 +/- 3.5 vs 17.3 +/- 2.5) (+/-SEM) and at 72 hr (29.0 +/- 4.8 vs 25.0 +/- 4.1) after injection of platelets (p = .02). Dacron vascular grafts. Similarly, the planar graft/blood ratio was reduced at 24 hr (2.7 +/- 0.5 vs 2.4 +/- 0.5), 48 hr (3.7 +/- 0.9 vs 3.1 +/- 0.7), and 72 hr (4.0 +/- 0.9 vs 3.6 +/- 0.8) (p = .04). We conclude that aspirin (325 mg tid) plus dipyridamole (75 mg tid) reduces platelet accumulation on long-term Dacron vascular grafts

Rib Bone Graft Adjusted to Fit the Facial Asymmetry: A Frame Structure Graft.

Science.gov (United States)

Lee, Yoon Ho; Choi, Jong Hwan; Hwang, Kun; Choi, Jun Ho

2015-10-01

The authors introduce the concept of a "frame structure graft" in which a harvested rib bone was adjusted to fit facial asymmetry. On the costochondral junction of the sixth or seventh rib, a 5 cm incision was made. Through a subperiosteal dissection, the rib bone was harvested. Using a reciprocating saw, the harvested rib was scored on its anterior surface as well as its posterior surface with a partial depth at different intervals. The harvested rib bone was placed on the skin surface of the unaffected side of the face and a curvature was created exactly matching that of the unaffected side by bending the bone using a greenstick fracture. Thereafter, the graft was adjusted to conceal the asymmetry of the deficient side. The adjusted "frame structure" was transferred to the defect through the incisions on the affected side, and the "frame structure" graft was placed on the mandible or zygoma. The graft fixation was done externally with at least 2 Kirschner wires (K-wires). From January 2005 to August 2013, a total of 30 patients (13 men, 17 women, mean age 25.6 years) received a frame structure graft. All 30 patients achieved good healing at the operation site without complications. Donor-site morbidity as pneumothorax from the rib bone harvest was not found. Merits of this frame structure graft, the authors think, are that this method could allow a similar curvature to the normal side. In addition, the procedure itself is easy.

Graft copolymers of polypropylene films. 1. radiation induced grafting of mixed monomers. Vol. 3

International Nuclear Information System (INIS)

El-Salmawi, K.M.; El-Naggar, A.M.; Said, H.M.; Zahran, A.H.

1996-01-01

Radiation graft copolymerization of co monomer mixtures of acrylic acid (AAC), and styrene (S) onto polypropylene (PP) film by mutual method has been investigated. The effects of different factors that may affect the grafting yield such as inhibitor concentration (Mohr's salt), solvent composition (MeOH and H 2 O), radiation dose and dose rate were considered. It was found that the role of Mohr's salt is very effective when the ratio of AAC in the co monomer mixtures was at lower values. However, the addition of 1.25 Wt% of Mohr's salt reduced the homo polymer formation and enhances the grafting process. Graft copolymerization in presence of solvent mixture composed of methanol and water was found to afford higher grafting than in pure methanol regardless of the composition of the co monomer mixture used. However, the highest degree of grafting was obtained at a solvent composition of 20% H 2 O:80%MeOH and a co monomer mixture of 20%AAC:80%sty. An attempt was made to determine each PAAC and PS fractions in the total graft yield obtained. Two methods of analysis based on using the reactivity ratios reported in literature, elemental analysis and IR spectroscopy. The determination of poly (acrylic acid) and polystyrene fractions by elemental analysis is believed more accurate than these by reactivity ratio. The precise results obtained by elemental analysis with respect to the chemical structure of known polymer prepared under identical conditions. The results obtained by IR measurements go well with that obtained with the reactivity ratio methods. 5 figs., 3 tabs

Biological Effects of Orthodontic Tooth Movement Into the Grafted Alveolar Cleft.

Science.gov (United States)

Sun, Jian; Zhang, Xiaoyue; Li, Renmei; Chen, Zhengxi; Huang, Yuanliang; Chen, Zhenqi

2018-03-01

Functional stimulus during orthodontic tooth movement into the grafted bone can lead to better alveolar bone grafting outcomes. The aim of this study was to analyze the biological effects of orthodontic tooth movement into the grafted alveolar cleft area with histologic staining, fluorescence staining, and real-time polymerase chain reaction (PCR). An animal model of orthodontic tooth movement into the grafted alveolar cleft area was established in 8-week-old Sprague-Dawley rats. The animals were divided into the experimental group and the control group. Four checkpoints were observed: before orthodontic stimuli, day 1 after orthodontic stimuli, day 3 after orthodontic stimuli, and day 5 after orthodontic stimuli. The cleft bone formation conditions, including the collagen fibers and the activities of the osteoclasts and osteoblasts, were evaluated by histologic staining. The expression of tartrate-resistant acid phosphatase (TRAP), receptor activator nuclear factor κB ligand, and Runt-related transcription factor 2 was detected by real-time PCR in both groups. Hematoxylin-eosin staining showed that the remodeling process of iliac autografts was completed when the orthodontic stress was applied, whereas the bone tissues first showed osteoclastogenesis and then osteogenesis. On the basis of TRAP staining, the osteoclasts increased to the maximal amount on day 3 and decreased thereafter. Evidence from tetracycline fluorescence staining indicated that no obvious changes in osteoblast activity were detected at the early stage; however, it gradually increased, especially in the region close to the root surface. According to real-time PCR, the expression of TRAP increased in both the early and middle stages, that of receptor activator nuclear factor κB ligand increased in the early stage, and that of Runt-related transcription factor 2 increased in the late stage. Moreover, the results showed significant differences between the experimental and control groups

Imaging features of anterior cruciate ligament reconstruction graft insufficiency

International Nuclear Information System (INIS)

Shang Yao; Zhang Yue; Tian Chunyan; Zheng Zhuozhao

2011-01-01

Objective: To investigate the imaging features of anterior cruciate ligament (ACL) graft insufficiency. Methods: X-Ray and MR imaging examinations in 24 consecutive patients who had ACL reconstructive graft insufficiency were retrospectively evaluated for tunnel position, osteoarthrosis and its related complications. Follow-up arthroscopy showed 16 graft tears and 8 graft laxities. Fisher exact test was used to compare tunnel malpositions, the proportion of graft tear on MRI and osteoarthrosis between graft tear group and graft laxity group. Results: Two malpositions of tibial tunnel and 3 malpositions of femoral tunnel were seen in graft tear group. Three-malpositions of tibial tunnel and 4 malpositions of femoral tunnel were seen in graft laxity group. The proportion of tibial or femoral malposition showed no significant difference between the two groups (P=0.289, P=0.167). In graft tear group, 15 complete graft tears were diagnosed correctly, 1 partial tear was misdiagnosed as normal on MRI. In graft laxity group, 4 grafts were diagnosed as normal and 4 were considered as graft tear on MRI. A significant difference was seen between the two groups (P=0.028) in the proportion of graft tear diagnosed on MRI. Fourteen osteoarthrosis were seen in graft tear group and 5 in graft laxity group. No significant difference was seen between the two groups (P= 0.289) in the proportion of osteoarthrosis. Conclusion: The proportions of tunnel malposition and osteoarthrosis showed no significant difference between the graft tear group and graft Laxity group. Most graft tears can be diagnosed accurately on MRI, but some cases of graft laxity may be misdiagnosed for graft tear. (authors)

Capturing of staphylococcus aureus onto an interface containing graft chains

International Nuclear Information System (INIS)

Lee, W.; Furusaki, Shintaro; Saito, Kyoichi; Sugo, Takanobu; Makuuchi, Keizo.

1995-01-01

A microbial-cell-capturing material was prepared by radiation-induced grafting of glycidyl methacrylate onto a polyethylene-based fiber before the introduction of diethylamine. The prepared fiber was tested against a Staphylococcus aureus and Escherichia coli solution. The results showed that the grafted-type fiber had a capturing rate constant 1000-fold higher than the commercial crosslinked-type bead for S. aureus and that an activation energy of 39 kJ/mol was obtained for the microbial-cell-capturing action. (author)

Inheritance of graft compatibility in Douglas fir.

Science.gov (United States)

D.L. Copes

1973-01-01

Graft compatibility of genetically related and unrelated rootstock-scion combinations was compared. Scion clones were 75% compatible when grafted on half-related rootstocks but only 56% compatible when grafted on unrelated rootstocks. Most variance associated with graft incompatibility in Douglas-fir appears to be caused by multiple genes.

Bone graft revascularization strategies

NARCIS (Netherlands)

Willems, W.F.

2014-01-01

Reconstruction of avascular necrotic bone by pedicled bone grafting is a well-known treatment with little basic research supporting its application. A new canine model was used to simulate carpal bone avascular necrosis. Pedicled bone grafting proved to increase bone remodeling and bone blood flow,

Radiation-induced grafting of acrylamide onto guar gum in aqueous medium: Synthesis and characterization of grafted polymer guar-g-acrylamide

Energy Technology Data Exchange (ETDEWEB)

Biswal, Jayashree [Radiation Technology Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085 (India); Kumar, Virendra [Radiation Technology Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085 (India); Bhardwaj, Y.K. [Radiation Technology Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085 (India)]. E-mail: ykbhard@magnum.barc.ernet.in; Goel, N.K. [Radiation Technology Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085 (India); Dubey, K.A. [Radiation Technology Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085 (India); Chaudhari, C.V. [Radiation Technology Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085 (India); Sabharwal, S. [Radiation Technology Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085 (India)

2007-10-15

Mutual radiation grafting technique has been applied to carry out grafting of acrylamide (AAm) onto guar gum (GG) using high-energy Co{sup 60} {gamma} radiation to enhance its flocculating properties for industrial effluents. The grafted product was characterized using analytical probes like elemental analysis, thermal analysis, Fourier transformed infrared (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The grafting extent was observed to decrease with the dose rate and increase with the concentration of AAm. Thermo gravimetric analysis (TGA) of grafted and ungrafted samples indicated better stability of grafted product. {gamma} and microwave radiation effect on grafted and virgin GG has also been reported.

Vascular graft infections with Mycoplasma

DEFF Research Database (Denmark)

Levi-Mazloum, Niels Donald; Skov Jensen, J; Prag, J

1995-01-01

laboratory techniques, the percentage of culture-negative yet grossly infected vascular grafts seems to be increasing and is not adequately explained by the prior use of antibiotics. We have recently reported the first case of aortic graft infection with Mycoplasma. We therefore suggest the hypothesis...... that the large number of culture-negative yet grossly infected vascular grafts may be due to Mycoplasma infection not detected with conventional laboratory technique....

Graft infections after surgical aortic reconstructions

NARCIS (Netherlands)

Berger, P.

2015-01-01

Prosthetic vascular grafts are frequently used to reconstruct (part) of the aorta. Every surgical procedure caries a certain risk for infection and when a prosthetic aortic graft is implanted, this may lead to an aortic graft infection (AGI). Endovascular techniques have gradually replaced open

Grafting of watermelon (Citrullus lanatus cv. Mahbubi) onto different squash rootstocks as a means to minimize cadmium toxicity.

Science.gov (United States)

Shirani Bidabadi, Siamak; Abolghasemi, Reza; Zheng, Si-Jun

2018-06-07

To test the possibility that using appropriate rootstocks could improve the tolerance of watermelon to cadmium (Cd) toxicity, a greenhouse experiment was conducted to determine growth and antioxidant activities of watermelons, either nongrafted or grafted onto summer squash and winter squash. We provided nutrient solutions having four levels (0, 50, 100, and 200 μM) of cadmium to treat the plants. Shoot and root biomass reduction were significantly lower in summer squash rootstock-grafted watermelon than winter squash rootstock-grafted and nongrafted watermelons. Cadmium induced a smaller decrease in leaf area index in grafted watermelons compared with nongrafted plants. The Cd- related reductions in chlorophyll content and efficiency of photosynthesis were more severe in nongrafted watermelons compared with dose grafted onto summer squash. Cd accumulation in shoot at the highest dose (200 µM) of CdCl 2 was significantly lower (19.76 mg/kg) in summer squash rootstock-grafted watermelon compared with winter squash rootstock-grafted (37.58 mg/kg) and nongrafted watermelon (72.12 mg/kg). H 2 O 2 , MDA production and electrolyte leakage of summer squash rootstock-grafted watermelon showed less increase, which was associated with a significant increase in the activities of antioxidant. The improved crop performance of grafted watermelons was attributed to their strong capacity to inhibit Cd accumulation in the aerial parts.

Hemocompatible control of sulfobetaine-grafted polypropylene fibrous membranes in human whole blood via plasma-induced surface zwitterionization.

Science.gov (United States)

Chen, Sheng-Han; Chang, Yung; Lee, Kueir-Rarn; Wei, Ta-Chin; Higuchi, Akon; Ho, Feng-Ming; Tsou, Chia-Chun; Ho, Hsin-Tsung; Lai, Juin-Yih

2012-12-21

In this work, the hemocompatibility of zwitterionic polypropylene (PP) fibrous membranes with varying grafting coverage of poly(sulfobetaine methacrylate) (PSBMA) via plasma-induced surface polymerization was studied. Charge neutrality of PSBMA-grafted layers on PP membrane surfaces was controlled by the low-pressure and atmospheric plasma treatment in this study. The effects of grafting composition, surface hydrophilicity, and hydration capability on blood compatibility of the membranes were determined. Protein adsorption onto the different PSBMA-grafted PP membranes from human fibrinogen solutions was measured by enzyme-linked immunosorbent assay (ELISA) with monoclonal antibodies. Blood platelet adhesion and plasma clotting time measurements from a recalcified platelet-rich plasma solution were used to determine if platelet activation depends on the charge bias of the grafted PSBMA layer. The charge bias of PSBMA layer deviated from the electrical balance of positively and negatively charged moieties can be well-controlled via atmospheric plasma-induced interfacial zwitterionization and was further tested with human whole blood. The optimized PSBMA surface graft layer in overall charge neutrality has a high hydration capability and keeps its original blood-inert property of antifouling, anticoagulant, and antithrmbogenic activities when it comes into contact with human blood. This work suggests that the hemocompatible nature of grafted PSBMA polymers by controlling grafting quality via atmospheric plasma treatment gives a great potential in the surface zwitterionization of hydrophobic membranes for use in human whole blood.

Graft copolymers of polypropylene films. 1. radiation induced grafting of mixed monomers. Vol. 3

Energy Technology Data Exchange (ETDEWEB)

El-Salmawi, K M; El-Naggar, A M; Said, H M; Zahran, A H [Radiation Chemistry Department, National Center for Radiation Research and Technology, Atomic Energy Authority, Cairo, (Egypt)

1996-03-01

Radiation graft copolymerization of co monomer mixtures of acrylic acid (AAC), and styrene (S) onto polypropylene (PP) film by mutual method has been investigated. The effects of different factors that may affect the grafting yield such as inhibitor concentration (Mohr`s salt), solvent composition (MeOH and H{sub 2} O), radiation dose and dose rate were considered. It was found that the role of Mohr`s salt is very effective when the ratio of AAC in the co monomer mixtures was at lower values. However, the addition of 1.25 Wt% of Mohr`s salt reduced the homo polymer formation and enhances the grafting process. Graft copolymerization in presence of solvent mixture composed of methanol and water was found to afford higher grafting than in pure methanol regardless of the composition of the co monomer mixture used. However, the highest degree of grafting was obtained at a solvent composition of 20% H{sub 2} O:80%MeOH and a co monomer mixture of 20%AAC:80%sty. An attempt was made to determine each PAAC and PS fractions in the total graft yield obtained. Two methods of analysis based on using the reactivity ratios reported in literature, elemental analysis and IR spectroscopy. The determination of poly (acrylic acid) and polystyrene fractions by elemental analysis is believed more accurate than these by reactivity ratio. The precise results obtained by elemental analysis with respect to the chemical structure of known polymer prepared under identical conditions. The results obtained by IR measurements go well with that obtained with the reactivity ratio methods. 5 figs., 3 tabs.

Dynamics of bone graft healing around implants

Directory of Open Access Journals (Sweden)

Narayan Venkataraman

2015-01-01

A few questions arise pertaining to the use of bone grafts along with implants are whether these are successful in approximation with implant. Do they accelerate bone regeneration? Are all defects ultimately regenerated with new viable bone? Is the bone graft completely resorbed or integrated in new bone? Does the implant surface characteristic positively affect osseointegration when used with a bone graft? What type of graft and implant surface can be used that will have a positive effect on the healing type and time? Finally, what are the dynamics of bone graft healing around an implant? This review discusses the cellular and molecular mechanisms of bone graft healing in general and in vicinity of another foreign, avascular body, namely the implant surface, and further, the role of bone grafts in osseointegration and/or clinical success of the implants.

Coronary artery bypass grafts: assessment of graft patency and native coronary artery lesions using 16-slice MDCT

Energy Technology Data Exchange (ETDEWEB)

Stauder, Norbert I.; Drosch, Tanja; Claussen, Claus D.; Kopp, Andreas F. [Eberhard-Karls-University, Department of Diagnostic Radiology, Tuebingen (Germany); Kuettner, Axel [Friedrich-Alexander-University, Department of Diagnostic Radiology, Erlangen (Germany); Schroeder, Stephen; Beck, Torsten [Eberhard-Karls-University, Department of Internal Medicine, Division Cardiology, Tuebingen (Germany); Stauder, Heidrun [Eberhard-Karls-University, Department of Thoracic and Cardiovascular Surgery, Tuebingen (Germany); Blumenstock, Gunnar [Eberhard-Karls-University, Department of Medical Information Processing, Tuebingen (Germany)

2006-11-15

The objective of this study was to evaluate the accuracy of electrocardiography (ECG)-gated 16-slice multidetector-row computed tomography (MDCT) in detection of stenosis of bypass grafts and native coronary arteries in patients who have undergone coronary artery bypass grafting (CABG). ECG-gated contrast-enhanced MDCT using 12 x 0.75-mm collimation was performed in 20 patients with recurrent angina 4.75 years after undergoing CABG. A total of 50 grafts, 16 arterial and 34 venous, were examined. All graft and coronary segments were evaluated for stenosis in comparison with conventional coronary angiography (CCA). Among the 80 arterial graft segments, 62 could be assessed (77.5%). Sensitivity, specificity, and positive and negative predictive values for stenosis were 96.2%, 97.2%, 96.2%, and 97.2%, respectively. In a total of 180 venous graft segments, 167 could be assessed. Sensitivity, specificity, and positive and negative predictive values for stenosis were 98.5%, 93.9%, 91.8%, and 98.9%, respectively. MDCT could assess 179 of 260 native coronary artery segments (68.8%).Sensitivity, specificity, and positive and negative predictive values for stenosis were 92.1%, 76.9%, 87.5%, and 84.7%, respectively. Sixteen-slice MDCT provides excellent image quality and diagnostic accuracy in detection of graft and coronary artery lesions in patients with suspected graft dysfunction. (orig.)

Tuning the Mechanical Properties of Polymer Nanocomposites Filled with Grafted Nanoparticles by Varying the Grafted Chain Length and Flexibility

Directory of Open Access Journals (Sweden)

Zixuan Wang

2016-08-01

Full Text Available By employing coarse-grained molecular dynamics simulation, we simulate the spatial organization of the polymer-grafted nanoparticles (NPs in homopolymer matrix and the resulting mechanical performance, by particularly regulating the grafted chain length and flexibility. The morphologies ranging from the agglomerate, cylinder, sheet, and string to full dispersion are observed, by gradually increasing the grafted chain length. The radial distribution function and the total interaction energy between NPs are calculated. Meanwhile, the stress–strain behavior of each morphology and the morphological evolution during the uniaxial tension are simulated. In particular, the sheet structure exhibits the best mechanical reinforcement compared to other morphologies. In addition, the change of the grafted chain flexibility to semi-flexibility leads to the variation of the morphology. We also find that at long grafted chain length, the stress–strain behavior of the system with the semi-flexible grafted chain begins to exceed that of the system with the flexible grafted chain, attributed to the physical inter-locking interaction between the matrix and grafted polymer chains. A similar transition trend is as well found in the presence of the interfacial chemical couplings between grafted and matrix polymer chains. In general, this work is expected to help to design and fabricate high performance polymer nanocomposites filled with grafted NPs with excellent and controllable mechanical properties.

New method for immobilization of biomolecules using preirradiation grafting at low temperature

Energy Technology Data Exchange (ETDEWEB)

Liang Chang Dong; Hoffman, A.S.

1986-01-01

A new method of biomolecule immobilization is described in which a monomer-conjugated enzyme (asparaginase, Asp) is grafted together with free monomer (acrylamide, AAm) onto a cellulose sheet which had been preirradiated in a /sup 60/Co source. The preirradiation and grafting steps are carried out in air at - 78/sup 0/C and in vacuum at 0/sup 0/C respectively. The grafting is probably caused by trapped radicals. The immobilized enzyme retains significant activity and is stable to storage. The technique is applicable to immobilization of a wide variety of biomolecules, such as enzymes, antibodies and drugs. The products may be used for therapeutic or diagnostic applications.

Acromioclavicular joint reconstruction using a tendon graft: a biomechanical study comparing a novel “sutured throughout” tendon graft to a standard tendon graft

Directory of Open Access Journals (Sweden)

Naziri Qais

2016-01-01

Full Text Available Background: With a recurrence rate of over 30%, techniques that offer stronger acromioclavicular (AC joint reconstruction through increased graft strength may provide longevity. The purpose of our study was to determine the biomechanical strength of a novel tendon graft sutured throughout compared to a native tendon graft in Grade 3 anatomical AC joint reconstruction. Methods: For this in vitro experiment, nine paired (n = 18 embalmed cadaveric AC joints of three males and six females (age 86 years, range 51–94 years were harvested. Anatomic repair with fresh bovine Achilles tendon grafts without bone block was simulated. Specimens were divided into two groups; with group 1 using grafts with ultra-high molecular-weight polyethylene (UHMWPE suture ran throughout the entire length. In group 2, reconstruction with only native allografts was performed. The distal scapula and humerus were casted in epoxy compound and mounted on the mechanical testing machine. Tensile tests were performed using a mechanical testing machine at the rate of 50 mm/min. Maximum load and displacement to failure were collected. Results: The average load to failure was significantly higher for group 1 compared to group 2, with mean values of 437.5 N ± 160.7 N and 94.4 N ± 43.6 N, (p = 0.001. The average displacement to failure was not significantly different, with 29.7 mm ± 10.6 mm in group 1 and 25 mm ± 9.1 mm in group 2 (p = 0.25. Conclusion: We conclude that a UHMWPE suture reinforced graft can provide a 3.6 times stronger AC joint reconstruction compared to a native graft.

Physical properties of agave cellulose graft polymethyl methacrylate

Energy Technology Data Exchange (ETDEWEB)

Rosli, Noor Afizah; Ahmad, Ishak; Abdullah, Ibrahim; Anuar, Farah Hannan [Polymer Research Centre (PORCE), School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi Selangor (Malaysia)

2013-11-27

The grafting polymerization of methyl methacrylate and Agave cellulose was prepared and their structural analysis and morphology were investigated. The grafting reaction was carried out in an aqueous medium using ceric ammonium nitrate as an initiator. The structural analysis of the graft copolymers was carried out by Fourier transform infrared and X-ray diffraction. The graft copolymers were also characterized by field emission scanning electron microscopy (FESEM). An additional peak at 1732 cm{sup −1} which was attributed to the C=O of ester stretching vibration of poly(methyl methacrylate), appeared in the spectrum of grafted Agave cellulose. A slight decrease of crystallinity index upon grafting was found from 0.74 to 0.68 for cellulose and grafted Agave cellulose, respectively. Another evidence of grafting showed in the FESEM observation, where the surface of the grafted cellulose was found to be roughed than the raw one.

Utility of indium-111 labelled autologous platelets in the diagnosis of renal graft rejection

International Nuclear Information System (INIS)

Martin-Comin, J.; Roca, M.; Grino, J.M.; Paradell, C.; Caralps, A.

1982-01-01

The usefulness of In-111 labelled autologous platelets in the diagnosis of renal graft rejection was studied. The method is based on imaging of the graft area at 4, 24, 48 and 72 hours after the injection of the labelled cells. The study was done in 21 renal cadaveric transplant recipients: control group: four patients without evidence of rejection. No platelet uptake was observed in any of them. Study group: in 13 patients with acute rejection and 1 with chronic rejection graft tracer uptake was seen. In the 3 others with a non-immunological sudden impairment of renal function, no activity was detected in graft area. Changes in renal platelet trapping correlated with response to antirejection therapy

[The application of delayed skin grafting combined traction in severe joint cicatricial contracture].

Science.gov (United States)

Xu, Zihan; Zhang, Zhenxin; Wang, Benfeng; Sun, Yaowen; Guo, Yadong; Gao, Wenjie; Qin, Gaoping

2014-11-01

To investigate the effect of delayed skin grafting combined traction in severe joint cicatricial contracture. At the first stage, the joint cicatricial contracture was released completely with protection of vessels, nerves and tendons. The wound was covered with allogenetic skin or biomaterials. After skin traction for 7-14 days, the joint could reach the extension position. Then the skin graft was performed on the wound. 25 cases were treated from Mar. 2000 to May. 2013. Primary healing was achieved at the second stage in all the cases. The skin graft had a satisfactory color and elasticity. Joint function was normal. All the patients were followed up for 3 months to 11 years with no hypertrophic scar and contraction relapse, except for one case who didn' t have enough active exercise on shoulder joint. Delayed skin grafting combined traction can effectively increase the skin graft survival rate and improve the joint function recovery.

Grafting of acrylic acid on etched latent tracks induced by swift heavy ions on polypropylene films

International Nuclear Information System (INIS)

Mazzei, R.; Fernandez, A.; Garcia Bermudez, G.; Torres, A.; Gutierrez, M.C.; Magni, M.; Celma, G.; Tadey, D.

2008-01-01

In order to continue with a systematic study that include different polymers and monomers, the residual active sites produced by heavy ion beams, that remain after the etching process, were used to start the grafting process. To produce tracks, foils of polypropylene (PP) were irradiated with 208 Pb of 25.62 MeV/n. Then, these were etched and grafted with acrylic acid (AA) monomers. Experimental curves of grafting yield as a function of grafting time with the etching time as a parameter were measured. Also, the grating yield as a function of the fluence and etching time was obtained. In addition, the permeation of solutions, with different pH, through PP grafted foils was measured

PRFM enhance wound healing process in skin graft.

Science.gov (United States)

Reksodiputro, Mirta; Widodo, Dini; Bashiruddin, Jenny; Siregar, Nurjati; Malik, Safarina

2014-12-01

Facial plastic and reconstructive surgery often used skin graft on defects that cannot be covered primarily by a local flap. However, wound healing using skin graft is slow, most of the time the graft is contractured and the take of graft is not optimal. Platelet rich fibrin matrix (PRFM) is a new generation of concentrated platelets that produce natural fibrin and reported to speed up the healing process. Application of PRFM in the skin graft implants is expected to increase the survival of the graft. We used porcine as animal models to elucidate the effect of autologous PRFM on wound healing in full-thickness (FTSG) and split-thickness (STSG) skin grafts. Survival level of the skin graft was determined by using ImageJ software based on the formation of collagen type 1 and graft take. We observed that the use of PRFM in FTSG and STSG increased type 1 collagen formation. We also found that PRFM addition in STSG gave the best skin graft take. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Expansion of donor-reactive host T cells in primary graft failure after allogeneic hematopoietic SCT following reduced-intensity conditioning.

Science.gov (United States)

Koyama, M; Hashimoto, D; Nagafuji, K; Eto, T; Ohno, Y; Aoyama, K; Iwasaki, H; Miyamoto, T; Hill, G R; Akashi, K; Teshima, T

2014-01-01

Graft rejection remains a major obstacle in allogeneic hematopoietic SCT following reduced-intensity conditioning (RIC-SCT), particularly after cord blood transplantation (CBT). In a murine MHC-mismatched model of RIC-SCT, primary graft rejection was associated with activation and expansion of donor-reactive host T cells in peripheral blood and BM early after SCT. Donor-derived dendritic cells are at least partly involved in host T-cell activation. We then evaluated if such an expansion of host T cells could be associated with graft rejection after RIC-CBT. Expansion of residual host lymphocytes was observed in 4/7 patients with graft rejection at 3 weeks after CBT, but in none of the 17 patients who achieved engraftment. These results suggest the crucial role of residual host T cells after RIC-SCT in graft rejection and expansion of host T cells could be a marker of graft rejection. Development of more efficient T cell-suppressive conditioning regimens may be necessary in the context of RIC-SCT.

Improvement of polymer stability by radiation grafting

International Nuclear Information System (INIS)

Ranogajec, F.; Mlinac-Misak, M.

1999-01-01

Losses of the stabilizer due to extractability or volatility immediately affect ultimate performance of polymer product. A new approach to increase the persistence of the stabilizer in the final product is to chemically bind it to the polymer backbone. Radiation grafting or crosslinking could be an efficient method for this, when the stabilizer is polymerizable. By a mutual gamma irradiation method, photoprotector 2-hydroxy-4-(3-methacryloxy-2- hydroxy-propoxy) benzophenone (HMB) has been readily grafted to low density polyethylene (LDPE) in benzene, tetrahydrofuran and methanol solution, respectively. Surface grafting occurs in a methanol solution of stabilizer, while in benzene and tetrahydrofuran solutions of stabilizer, grafting proceeds more or less in the inner parts of the polymeric film as well. The grafted LDPE film in methanol and tetrahydrofuran (containing 1 w/w % of grafted HMB), 1 w/w % blended HMB with LDPE and nongrafted LDPE film, were all exposed to accelerated aging and natural weathering and their spectral changes, expressed by the carbonyl index, were then compared. The change of elongation at break and tensile strength were measured in the course of aging. UV stability tests on aged films and change in mechanical properties indicate a pronounced protective effect achieved by grafted stabilizer. Grafting in methanol solution appears to be an efficient photostabilization treatment and the most economical with respect to the consumption of monomer, the grafting yield being less than 0.5%. Surface grafting is an efficient photostabilization method since grafted stabilizer is chemically bound to a polymeric surface and in this way the problem of evaporation of blended stabilizers during the prolonged use of polymeric materials is eliminated. (author)

Modification of polyetherurethane for biomedical application by radiation induced grafting. II. Water sorption, surface properties, and protein adsorption of grafted films

International Nuclear Information System (INIS)

Jansen, B.; Ellinghorst, G.

1984-01-01

A series of polyetherurethane films grafted by means of gamma radiation with hydrophilic or reactive monomers (2-hydroxyethyl methacrylate, 2,3-epoxypropyl methacrylate, 2,3-dihydroxypropyl methacrylate, and acrylamide) and partially chemically modified were subjected to various physico-chemical investigation methods involving water sorption, contact angle, and protein adsorption measurements. From contact angle data the interfacial free energy gamma sw between grafted films and water was calculated. It was found that the water uptake of grafted films increases with grafting yield or, in the case of grafted and afterwards chemically modified films, with reaction yield; the diffusion coefficient of water in the modified films also increases with grafting yield. Contact angle studies revealed all grafted films to have surfaces more hydrophilic than the ungrafted trunk polymer. The degree of hydrophilicity--especially of HEMA-grafted films--strongly depends on grafting conditions. For some grafted samples with high surface hydrophilicity very low interfacial free energies approaching zero were measured. The study of the competitive adsorption of bovine serum albumin, gamma-globulin, and fibrinogen from a synthetic protein solution onto modified films showed that the adsorption of albumin increases markedly with increasing grafting yields, whereas the fibrinogen and gamma-globulin adsorption only slightly increases. A correlation between interfacial free energy and protein adsorption in the sense of the minimum interfacial free energy hypothesis was found only for samples with grafting yields below 5%. At higher grafting yields the increased surface area complicates the analysis

Homogeneous cation exchange membrane by radiation grafting

International Nuclear Information System (INIS)

Kolhe, Shailesh M.; G, Agathian; Ashok Kumar

2001-01-01

Preparation of a strong cation exchange membrane by radiation grafting of styrene on to polyethylene (LDPE) film by mutual irradiation technique in the presence of air followed by sulfonation is described. The grafting has been carried out in the presence of air and without any additive. Low dose rate has been seen to facilitate the grafting. Further higher the grafting percentage more is the exchange capacity. The addition of a swelling agent during the sulfonation helped in achieving the high exchange capacity. The TGA-MASS analysis confirmed the grafting and the sulfonation. (author)

Nuclear accidents and bone marrow graft

International Nuclear Information System (INIS)

Bernard, J.

1988-01-01

In case of serious contamination, the only efficacious treatment is the bone marrow grafts. The graft types and conditions have been explained. To restrict the nuclear accidents consequences, it is recommended to: - take osseous medulla of the personnel exposed to radiations and preserve it , that permits to carry out rapidly the auto-graft in case of accidents; - determine, beforehand, the HLA group of the personnel; - to register the voluntary donors names and addresses, and their HLA group, that permits to find easily a compatible donar in case of allo-graft. (author)

Enhancement of the grafting performance and of the water absorption of cassava starch graft copolymer by gamma radiation

International Nuclear Information System (INIS)

Kiatkamjornwong, Suda; Meechai, Nispa

1997-01-01

Enhancement of the gamma radiation grafting of acrylonitrile onto gelatinized cassava starch was investigated. Infrared spectrometry was used to follow the chemical changes in the grafting reaction and from saponification. The saponified starch-g-PAN (HSPAN) was then characterized in terms of grafting parameters to provide a guide for the optimum total dose (kGy) and the appropriate ratio of starch/acrylonitrile for a fixed dose rate of 2.5 x 10 -1 kGy/min. Other dose rates were also carried out to obtain the appropriate result of grafting copolymerization and of water absorption. A thin aluminium foil, covering the inner wall of the reaction vessel, was found to be far more effective than any other metal films in the enhancement of the grafting reaction and the water absorption as well. Nitric acid in the medium increases the grafting yield and the water absorption. Methyl ether hydroquinone inhibitor was evaluated for its ability to increase homopolymerization and decrease graft reaction. When styrene was used as a comonomer, it hampered the grafting of acrylonitrile onto starch backbone. The water absorption capacity was improved by freeze-drying the HSPAN. The treatment of the HSPAN with aluminium trichloride hexahydrate was found to enhance the degree of wicking, but to decrease the water absorbency. (author)

Bypass grafting to the anterior tibial artery.

Science.gov (United States)

Armour, R H

1976-01-01

Four patients with severe ischaemia of a leg due to atherosclerotic occlusion of the tibial and peroneal arteries had reversed long saphenous vein grafts to the patent lower part of the anterior tibial artery. Two of these grafts continue to function 19 and 24 months after operation respectively. One graft failed on the fifth postoperative day and another occluded 4 months after operation. The literature on femorotibial grafting has been reviewed. The early failure rate of distal grafting is higher than in the case of femoropopliteal bypass, but a number of otherwise doomed limbs can be salvaged. Contrary to widely held views, grafting to the anterior tibial artery appears to give results comparable to those obtained when the lower anastomosis is made to the posterior tibial artery.

Hydrogen, a potential safeguard for graft-versus-host disease and graft ischemia-reperfusion injury?

Science.gov (United States)

Yuan, Lijuan; Shen, Jianliang

2016-01-01

Post-transplant complications such as graft-versus-host disease and graft ischemia-reperfusion injury are crucial challenges in transplantation. Hydrogen can act as a potential antioxidant, playing a preventive role against post-transplant complications in animal models of multiple organ transplantation. Herein, the authors review the current literature regarding the effects of hydrogen on graft ischemia-reperfusion injury and graft-versus-host disease. Existing data on the effects of hydrogen on ischemia-reperfusion injury related to organ transplantation are specifically reviewed and coupled with further suggestions for future work. The reviewed studies showed that hydrogen (inhaled or dissolved in saline) improved the outcomes of organ transplantation by decreasing oxidative stress and inflammation at both the transplanted organ and the systemic levels. In conclusion, a substantial body of experimental evidence suggests that hydrogen can significantly alleviate transplantation-related ischemia-reperfusion injury and have a therapeutic effect on graft-versus-host disease, mainly via inhibition of inflammatory cytokine secretion and reduction of oxidative stress through several underlying mechanisms. Further animal experiments and preliminary human clinical trials will lay the foundation for hydrogen use as a drug in the clinic. PMID:27652837

Growth and decay of surface charges in grafts of Teflon in electrets states

International Nuclear Information System (INIS)

Spinelli, I.M.M.

1971-01-01

The greatest problem founded in a cardiovascular implant is the thrombus formation. Teflon grafts were used in electret state for prothesis in vena cava of dogs. To put these grafts in an electret state a corona discharge in air was used and homocharge was formed predominantly. To measure the formed surface charge the oscillating capacitor technique was used. In the electret state the grafts have showed an initial density of charge of 10- 8 C/cm 2 and the charge decay and time decay of the samples were measured under many conditions. We found two activation energies, E 2 =0.17 e V and E 3 =1.12 e V, due to rapid and slow decay, respectively. The charged grafts were sterilized with ethilene gas oxide and this process apparently did not influence the charges

Adaptive significance of root grafting in trees

Energy Technology Data Exchange (ETDEWEB)

Loehle, C.; Jones, R.

1988-12-31

Root grafting has long been observed in forest trees but the adaptive significance of this trait has not been fully explained. Various authors have proposed that root grafting between trees contributes to mechanical support by linking adjacent root systems. Keeley proposes that this trait would be of greatest advantage in swamps where soils provide poor mechanical support. He provides as evidence a greenhouse study of Nyssa sylvatica Marsh in which seedlings of swamp provenance formed between-individual root grafts more frequently than upland provenance seedlings. In agreement with this within-species study, Keeley observed that arid zone species rarely exhibit grafts. Keeley also demonstrated that vines graft less commonly than trees, and herbs never do. Since the need for mechanical support coincides with this trend, these data seem to support his model. In this paper, the authors explore the mechanisms and ecological significance of root grafting, leading to predictions of root grafting incidence. Some observations support and some contradict the mechanical support hypothesis.

Autologous patch graft in tube shunt surgery.

Science.gov (United States)

Aslanides, I M; Spaeth, G L; Schmidt, C M; Lanzl, I M; Gandham, S B

1999-10-01

To evaluate an alternate method of covering the subconjunctival portion of the tube in aqueous shunt surgery. Evidence of tube erosion, graft-related infection, graft melting, or other associated intraocular complications were evaluated. A retrospective study of 16 patients (17 eyes) who underwent tube shunt surgery at Wills Eye Hospital between July 1991 and October 1996 was conducted. An autologous either "free" or "rotating" scleral lamellar graft was created to cover the subconjunctival portion of the tube shunt. All patients were evaluated for at least 6 months, with a mean follow-up of 14.8 months (range 6-62 months). All eyes tolerated the autologous graft well, with no clinical evidence of tube erosion, or graft-related or intraocular complications. Autologous patch graft in tube shunt surgery appears--in selected cases--to be an effective, safe and inexpensive surgical alternative to allogenic graft materials. It also offers ease of availability, and eliminates the risk of transmitting infectious disease.

Delayed allogeneic skin graft rejection in CD26-deficient mice.

Science.gov (United States)

Zhao, Xiangli; Zhang, Kai; Daniel, Peter; Wisbrun, Natali; Fuchs, Hendrik; Fan, Hua

2018-03-23

Organ transplantation is an effective therapeutic tool for treating many terminal diseases. However, one of the biggest challenges of transplantation is determining how to achieve the long-term survival of the allogeneic or xenogeneic transplant by, for example, preventing transplant rejection. In the current study, CD26 gene-knockout mice were used to investigate the potential role of CD26/dipeptidyl peptidase-4 (DPPIV) in allogeneic skin graft rejection by tail-skin transplantation. Compared with wild-type (CD26 +/+ ) counterparts, CD26 -/- mice showed reduced necrosis of grafts and delayed graft rejection after skin transplantation. Concentrations of serum IgG, including its subclasses IgG1 and IgG2a, were significantly reduced in CD26 -/- mice during graft rejection. Moreover, after allogeneic skin transplantation, the secretion levels of the cytokines IFN-γ, IL-2, IL-6, IL-4, and IL-13 were significantly reduced, whereas the level of the cytokine IL-10 was increased in the serum of CD26 -/- mice compared with that in the serum of CD26 +/+ mice. Additionally, the concentration of IL-17 in serum and the percentage of cells secreting IL-17 in mouse peripheral blood lymphocytes (MPBLs) were both significantly lower, while the percentage of regulatory T cells (Tregs) was significantly higher in MPBLs of CD26 -/- mice than in those of CD26 +/+ mice. Furthermore, a lower percentage of CD8 + T cells in MPBLs and fewer infiltrated macrophages and T cells in graft tissues of CD26 -/- mice were detected during graft rejection. These results indicate that CD26 is involved in allogeneic skin graft rejection and provides another hint that CD26 deficiency leads to less rejection due to lower activation and proliferation of host immune cells.

Radiation-induced grafting of styrene on to LDPE films for preparation of cation exchange membranes, i. effect of grafting conditions

International Nuclear Information System (INIS)

Mohamed Mahmoud Nasef; Hamdani Saidi; Hussin Mohd Nor; Khairul Zaman Mohd Dahlan; Kamaruddin Hashim

1999-01-01

PE-g-polystyrene copolymers were prepared by simultaneous radiation-induced graft copolymerization of styrene onto low density polyethylene (LDPE) films. The effects of irradiation conditions such as monomer concentration, Mohr's salt and sulfuric acid addition, irradiation dose and dose rate were investigated. It was found that the degree of grafting increases with the monomer concentration and reaches its maximum value at styrene concentration of 80 vol %. The addition of Mohr's salt as well as sulfuric acid caused a considerable increase in the degree of grafting with various styrene concentrations. The degree of grafting also increased with the increased in irradiation dose, however it remarkably decreased with the increase in dose rate. The formation of graft copolymers was confirmed by FTIR analysis. The structural investigation of the graft copolymer was carried out by x-ray diffraction (XRD). The degree of crystallinity content was found to be decreased with the increase in the degree of grafting and influenced the mechanical properties of the graft copolymer to some extent. (Author)

Complications in skin grafts when continuing antithrombotic therapy prior to cutaneous surgery requiring skin grafting

DEFF Research Database (Denmark)

Jarjis, Reem Dina; Jørgensen, Lone; Finnerup, Kenneth

2015-01-01

Abstract The risk of postoperative bleeding and wound healing complications in skin grafts among anticoagulated patients undergoing cutaneous surgery has not been firmly established. The objective was to examine the literature and assess the risk of postoperative bleeding or wound healing...... complications in skin grafts among anticoagulated patients, compared with patients who discontinue or patients who are not receiving antithrombotic therapy prior to cutaneous surgery requiring skin grafting. A systematic review examining the effect of antithrombotic therapy on cutaneous surgery was performed...... studies were of prospective and retrospective design. Most of the reviewed studies suggest that the use of antithrombotic therapy can increase the risk of bleeding complications in skin grafts. These complications are only wound threatening and not life threatening. Therefore, this is of concern mostly...

Cadaveric aorta implantation for aortic graft infection.

Science.gov (United States)

Ali, Asad; Bahia, Sandeep S S; Ali, Tahir

2016-01-01

This case report describes a 73-year-old gentleman who underwent explantation of an infected prosthetic aorto-iliac graft and replacement with a cryopreserved thoracic and aorto-iliac allograft. The patient has been followed up a for more than a year after surgery and remains well. After elective tube graft repair of his abdominal aortic aneurysm (AAA) in 2003, he presented to our unit in 2012 in cardiac arrest as a result of a rupture of the distal graft suture line due to infection. After resuscitation he underwent aorto-bifemoral grafting using a cuff of the original aortic graft proximally. Distally the new graft was anastomosed to his common femoral arteries, with gentamicin beads left in situ. Post discharge the patient was kept under close surveillance with serial investigations including nuclear scanning, however it became apparent that his new graft was infected and that he would require aortic graft replacement, an operation with a mortality of at least 50%. The patient underwent the operation and findings confirmed a synthetic graft infection. This tube graft was explanted and a cryopreserved aorta was used to the refashion the abdominal aorta and its bifurcation. The operation required a return to theatre day one post operatively for a bleeding side branch, which was repaired. The patient went on to make a full recovery stepping down from the intensive therapy unit day 6 post operatively and went on to be discharged 32 days after his cryopreserved aorta implantation. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Re-birth after coronary bypass graft surgery: a hermeneutic-phenomenological study.

Science.gov (United States)

Abbasi, Mohammad; Mohammadi, Nooredin; Nasrabadi, Alireza Nikbakht; Fuh, Suh Boudouin; Sadeghi, Tahereh

2014-03-31

Although coronary artery bypass graft surgery has significant effects on reducing the symptoms of coronary artery disease, there is not enough knowledge and understanding of lived experience of patients after surgery. Understanding lived experience of this group of patients would be helpful for healthcare staff to provide better services to the patients. The aim of this study was to describe with a deeper understanding, the lived experiences of patients after Coronary Artery Bypass Graft Surgery. Using a hermeneutic phenomenological approach and a Van-Manen analysis method, in-depth semi-structured interviews were conducted with eleven participants who had lived experienced of at least six months post - coronary artery bypass graft surgery. Re-birth was the main theme that emerged in the process of data analysis. This theme was derived from four sub-themes including "feels younger", ''vigorous heart'', ''intrepid life'' and ''oriented to be healthy''. Life after a coronary artery bypass graft surgery is often appreciated as a re-birth by persons with these experiences as surgery did not only provide a feeling of wellness, but also added a sensation of youthfulness and improvement in the quality of life for these participants. In addition, they would actively participate in health promotional activities such as; adherence to medication and diet regimes, changes in lifestyle to maintain their health.

The graft polymers from different species of lignin and acrylic acid: synthesis and mechanism study.

Science.gov (United States)

Ye, De zhan; Jiang, Li; Ma, Chao; Zhang, Ming-hua; Zhang, Xi

2014-02-01

The influence of lignin species on the grafting mechanism of lignosulfonate (from eucalyptus and pine, recorded as HLS and SLS, respectively) with acrylic acid (AA) was investigated. The graft polymers were confirmed by the absorption of carbonyl groups in the FTIR spectra. The decreasing phenolic group's content (Ph-OH) is not only due to its participation as grafting site but also to the negative effect of initiator. In the initial period (0-60 min), HLS and SLS both accelerate the polymerization of AA. Additionally, Ph-OH group's content is proportional to product yield (Y%), monomer conversion (C%) and grafting efficiency (GE%), strongly indicating that it acts as active center. Nevertheless, compared with HLS, Y% and C% in SLS grafting system are lower though it has higher Ph-OH group's content, which is due to the quinonoid structure formed by the self-conjugated of phenoxy radical in Guaiacyl unit. Finally, the lignosulfonate grafting mechanism was proposed. Copyright © 2013 Elsevier B.V. All rights reserved.

Corneal graft reversal: Histopathologic report of two cases.

Science.gov (United States)

Qahtani, Abdullah A; Alkatan, Hind M

2014-10-01

Graft reversal is a rare cause for failed PKP. In this case report we are presenting 2 graft failure cases in which the corneal grafts were reversed unintentionally. The onset of signs of graft failure, however was variable. We have included their clinical course and the histopathologic findings of the removed corneal grafts. A total of 6 cases including ours have been reported so far. The aim of this report is to attract the attention of corneal surgeons to an additional rare cause for failed penetrating keratoplasty (PKP) which is donor graft reversal.

Characterization and Some Properties of Functionalized Graft Copolymer

International Nuclear Information System (INIS)

Hegazy El-Sayed, A.; Kamal, H.; Mahmoud, Gh.A.; Khalifa, N.A.

2000-01-01

The study involved the investigation and characterization of membranes prepared by graft copolymerization of acrylonitrile (AN) and vinyl acetate (VAc) binary monomers onto low density polyethylene (LDPE) and isotactic polypropylene (IPP). The mutual gamma-irradiation method was used as a grafting technique. The effects of grafting and chemical treatments on the thermal properties and crystallinity of prepared graft copolymer have been investigated using DSC, TGA and XRD. IR spectra recorded before and after grafting and also for the chemically treated membranes to elucidate the structural changes occurred due to grafting and chemical treatments

Kinetic behaviour of graft copolymerisation of nitrogenous heterocyclic monomer onto EB-irradiated ETFE films

International Nuclear Information System (INIS)

Paveswari Sithambaranathan; Arshad Ahmad; Mohamed Mahmoud Nasef; Universiti Teknologi Malaysia Campus, Kuala Lumpur

2015-01-01

Kinetic behaviour of graft copolymerisation of a nitrogenous heterocyclic monomer, 4-vinylpyridine (4-VP), onto electron beam irradiated poly(ethylene-co-tetrafluoroethylene) (ETFE) films was investigated in correlation with reaction parameters (absorbed dose, monomer concentration and reaction temperature). This was established by determination of initial polymerisation rate (r p0 ), characteristic radical recombination rate (γ) and delay time (t 0 ). The orders of the dependence of the initial rate of grafting on the absorbed dose and monomer concentration were found to be 2.28 and 3.49, respectively. The effect of temperature was investigated in the range of 50-70 deg C and the activation energy was determined. The incorporation of poly(4-VP) grafts and the accompanied chemical changes in the grafted ETFE films were monitored using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, respectively. The results of the present study showed that a quantitative kinetic description for grafting of 4-VP onto ETFE can be established and the degree of grafting can be tuned by controlling the reaction parameters. (author)

Radiation-induced grafting onto wool

International Nuclear Information System (INIS)

Muller-Schulte, D.

1979-10-01

Radiation-induced grafting tests were done on single wool fibres. Different vinyl monomers were used for this purpose and they were grafted in twenty different solvents which were selected for their swelling effiency and solvent parameters. The tests were done once with and once without the addition of water. The presence of water causes the polymer uptake to increase considerably. Formic acid/methanol and methanol were found to be the most suitable solvent systems, as they have the highest hydrogen-bond interaction effiency. The moisture uptake of wool depends on the hydrophily and hydrophoby of the grafted polymers. The single-fibre tests serve as a basis for analogous grafting tests on wool fabrics. The permanent- press was improved by graftng with hydrophoric polymers and polymers with a high glass-transition temperature [af

Polyether-polyester graft copolymer

Science.gov (United States)

Bell, Vernon L. (Inventor)

1987-01-01

Described is a polyether graft polymer having improved solvent resistance and crystalline thermally reversible crosslinks. The copolymer is prepared by a novel process of anionic copolymerization. These polymers exhibit good solvent resistance and are well suited for aircraft parts. Previous aromatic polyethers, also known as polyphenylene oxides, have certain deficiencies which detract from their usefulness. These commercial polymers are often soluble in common solvents including the halocarbon and aromatic hydrocarbon types of paint thinners and removers. This limitation prevents the use of these polyethers in structural articles requiring frequent painting. In addition, the most popular commercially available polyether is a very high melting plastic. This makes it considerably more difficult to fabricate finished parts from this material. These problems are solved by providing an aromatic polyether graft copolymer with improved solvent resistance and crystalline thermally reversible crosslinks. The graft copolymer is formed by converting the carboxyl groups of a carboxylated polyphenylene oxide polymer to ionic carbonyl groups in a suitable solvent, reacting pivalolactone with the dissolved polymer, and adding acid to the solution to produce the graft copolymer.

Sugar-Grafted Cyclodextrin Nanocarrier as a "Trojan Horse" for Potentiating Antibiotic Activity.

Science.gov (United States)

Li, Min; Neoh, Koon Gee; Xu, Liqun; Yuan, Liang; Leong, David Tai; Kang, En-Tang; Chua, Kim Lee; Hsu, Li Yang

2016-05-01

The use of "Trojan Horse" nanocarriers for antibiotics to enhance the activity of antibiotics against susceptible and resistant bacteria is investigated. Antibiotic carriers (CD-MAN and CD-GLU) are prepared from β-cyclodextrin grafted with sugar molecules (D-mannose and D-glucose, respectively) via azide-alkyne click reaction. The sugar molecules serve as a chemoattractant enticing the bacteria to take in higher amounts of the antibiotic, resulting in rapid killing of the bacteria. Three types of hydrophobic antibiotics, erythromycin, rifampicin and ciprofloxacin, are used as model drugs and loaded into the carriers. The minimum inhibitory concentration of the antibiotics in the CD-MAN-antibiotic and CD-GLU-antibiotic complexes for Gram-negative Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumannii strains, and a number of Gram-positive Staphylococcus aureus strains, including the methicillin-resistant strains (MRSA), are reduced by a factor ranging from 3 to >100. The CD-MAN-antibiotic complex is also able to prolong the stability of the loaded antibiotic and inhibit development of intrinsic antibiotic resistance in the bacteria. These non-cytotoxic sugar-modfied nanocarriers can potentiate the activity of existing antibiotics, especially against multidrug-resistant bacteria, which is highly advantageous in view of the paucity of new antibiotics in the pipeline.

Improved patency and reduced intimal hyperplasia in PTFE grafts with luminal immobilized heparin compared with standard PTFE grafts at six months in a sheep model.

Science.gov (United States)

Pedersen, G; Laxdal, E; Ellensen, V; Jonung, T; Mattsson, E

2010-06-01

The aim of this study was to compare the performance of polytetrafluoroethylene (PTFE) grafts with luminal coating of immobilized heparin to that of standard PTFE grafts at six months. Twenty-eight common carotid arteries in fourteen sheep were bypassed with heparin-coated PTFE grafts (6 mm diameter, 6 cm length) on one side and standard PTFE grafts on the other. The grafts were explanted after six months. The thickness of intimal hyperplasia (IH) in open grafts was measured with histomorphometrical methods. Two of 14 heparinized PTFE grafts and nine of 14 grafts in the control PTFE-group were occluded at explantation (P=0.006). Six-month patency rates for heparinized PTFE grafts and for standard PTFE grafts were 86% and 36%, respectively. Mean graft anastomotic IH thickness in open grafts were 0.074 mm for heparinized PTFE grafts and 0.259 mm for PTFE-grafts (P=0.006). PTFE grafts with luminal coating containing immobilized heparin had significantly better patency and recruited less intimal hyperplasia than standard PTFE grafts at six months.

Thermo-responsive poly(N-isopropylacrylamide)-grafted hollow fiber membranes for osteoblasts culture and non-invasive harvest

Energy Technology Data Exchange (ETDEWEB)

Zhuang, Meiling, E-mail: zhuangmeiling2006@126.com; Liu, Tianqing, E-mail: liutq@dlut.edu.cn; Song, Kedong, E-mail: kedongsong@dlut.edu.cn; Ge, Dan, E-mail: gedan@dlut.edu.cn; Li, Xiangqin, E-mail: xiangqinli@163.com

2015-10-01

Hollow fiber membrane (HFM) culture system is one of the most important bioreactors for the large-scale culture and expansion of therapeutic cells. However, enzymatic and mechanical treatments are traditionally applied to harvest the expanded cells from HFMs, which inevitably causes harm to the cells. In this study, thermo-responsive cellulose acetate HFMs for cell culture and non-invasive harvest were prepared for the first time via free radical polymerization in the presence of cerium (IV). ATR-FTIR and elemental analysis results indicated that the poly(N-isopropylacrylamide) (PNIPAAm) was covalently grafted on HFMs successfully. Dynamic contact angle measurements at different temperatures revealed that the magnitude of volume phase transition was decreased with increasing grafted amount of PNIPAAm. And the amount of serum protein adsorbed on HFMs surface also displayed the same pattern. Meanwhile osteoblasts adhered and spread well on the surface of PNIPAAm-grafted HFMs at 37 °C. And Calcein-AM/PI staining, AB assay, ALP activity and OCN protein expression level all showed that PNIPAAm-grafted HFMs had good cell compatibility. After incubation at 20 °C for 120 min, the adhering cells on PNIPAAm-grafted HFMs turned to be round and detached after being gently pipetted. These results suggest that thermo-responsive HFMs are attractive cell culture substrates which enable cell culture, expansion and the recovery without proteolytic enzyme treatment for the application in tissue engineering and regenerative medicine. - Highlights: • PNIPAAm-grafted HFMs exhibited thermoresponsive characteristic. • The OB cells could adhere and spread well on the surface of PNIPAAm-grafted HFMs. • PNIPAAm-grafted HFMs do not significantly impact ALP activity and OCN protein expression level of OB cells. • Cell could be detached from PNIPAAm-grafted HFMs when temperature decreased from 37 °C to 20 °C.

Nanoscale zero-valent iron impregnation of covalent organic polymer grafted activated carbon for water treatment

DEFF Research Database (Denmark)

Mines, Paul D.; Uthuppu, Basil; Thirion, Damien

2016-01-01

The use of nanoscale zero valent iron (nZVI) has quickly become a leading research material for the treatment of typically hard to degrade contaminants found in groundwater. These contaminants include antibiotics, pesticides, halogenated organics, heavy metals, among others. However, the effectiv......The use of nanoscale zero valent iron (nZVI) has quickly become a leading research material for the treatment of typically hard to degrade contaminants found in groundwater. These contaminants include antibiotics, pesticides, halogenated organics, heavy metals, among others. However...... polymeric network already previously proven to stabilize nZVI and a long-standing water treatment material,1 activated carbon; we have developed an advanced material that allows for the not only the stabilization of nZVI, but also the improved degradation of various water contaminants. This was done...... by performing a series of surface modification techniques to the surface of the activated carbon, then physically grafting the covalent organic polymer to the carbon in a shell-like manner, and ultimately synthesizing nZVI in situ within the pores of both the activated carbon and the polymeric network. Not only...

Polyether/Polyester Graft Copolymers

Science.gov (United States)

Bell, Vernon L., Jr.; Wakelyn, N.; Stoakley, D. M.; Proctor, K. M.

1986-01-01

Higher solvent resistance achieved along with lower melting temperature. New technique provides method of preparing copolymers with polypivalolactone segments grafted onto poly (2,6-dimethyl-phenylene oxide) backbone. Process makes strong materials with improved solvent resistance and crystalline, thermally-reversible crosslinks. Resulting graft copolymers easier to fabricate into useful articles, including thin films, sheets, fibers, foams, laminates, and moldings.

Preparation of Dimethylaminoethylmethacrylate Grafted Polymeric Adsorbent by Using Radiation-Induced Grafting Technique for Removal of Anions

International Nuclear Information System (INIS)

Kavakli, P. A.

2006-01-01

The development of efficient separation and purification techniques is very important from industrial, environmental and economic points of view. Polymeric materials having polyfunctional groups such as carboxylic, amide, nitrile, iminodiacetic acid, amidoxime, and ammonium groups, etc., not only possess good hydrophilic properties, but also have good ion exchange properties which make them suitable for metal recovery from aqueous solutions. Radiation induced grafting is a powerful technique capable of controlling the introduction of various functional groups to the polymeric materials, keeping the original properties and especially the mechanical strength of the base material, and thus, allowing the synthesis of more stable polymeric adsorbents. The main objective of this study was to develop special polymeric adsorbents to remove NOx and PO 4 anions from aqueous systems. For this purpose, a novel nonwoven fabric was prepared by radiation-induced graft polymerization of imethylaminoethylmethacrylate (DMAEMA) onto polypropylene coated polyethylene nonwoven fabric. The trunk polymer was irradiated by electron beam at a voltage of 2 MeV and a current of 3 mA in a nitrogen atmosphere at dry-ice temperature at different doses. The degree of grafting was determined as a function of the total dose, monomer concentration, temperature, and reaction time. It was found that the degree of grafting of grafted polymer was greatly affected by reaction conditions. Grafting conditions were optimized, and about 150 % degree of grafting samples was used for further experiments. DMAEMA grafted polymer was later protonated by using acid solution to prepare adsorbent for the removal of anions. Adsorption experiments were performed in column mode for removal of phosphate. Approximately 2000 bed volumes of phosphate-free water can be produced from 10 ppb phosphate solution at high space velocity

Radiation induced graft copolymerization of jute fibre

International Nuclear Information System (INIS)

Al-Siddique, F.R.; Khan, A.U.; Sheikh, R.A.

1983-01-01

Graft copolymerized jute fibres (GCJF) were prepared by γ-ray induced graft copolymerization of various monomers onto bleached and de-waxed jute samples. The effect of γ-ray dose on the tendency of various monomers to form graft co-polymer was studied. It was found that the tendency decreases as follows: methylmethacrylate (MMA)>acrylonitrile (AN)>styrene (STY)>vinylacetate (VA). When the effect of monomer concentration on the formation of graft co-polymer was studied, it was found that a mixture of AN and STY gave a higher amount of grafting than what was observed for STY or AN alone, when used at a comparable concentration. A study on the effect of concentration of methyl alcohol (a swelling agent for jute) on the tendency of the monomers to form graft co-polymer showed that although there is no effect when only AN is used, an appreciable effect is observed if AN is mixed with STY. In the later case the tendency of graft co-polymerization increases with the increase of CH 3 OH concentration. It was further observed that the increase of CH 3 OH also has a positive influence on MMA to form graft co-polymer in the range of 40-90% CH 3 OH. The affinity of GCJF towards moisture has been found to decrease with the increase of polymer loading onto jute. The presence of swelling agents during graft copolymer formation was also found to decrease the affinity of GCJF towards moisture. (author)

Press-fit Femoral Fixation in ACL Reconstruction using Bone-Patellar Tendon-Bone Graft

Directory of Open Access Journals (Sweden)

Kaseb Mohammad Hasan

2009-05-01

Full Text Available Bone-patellar tendon auto graft is probably the most widely used graft for ACL reconstruction. Several methods for graft fixation have been described. To avoid intra-articular hardware we adopt biological fixation with a femoral trapezoidal press-fit fixation. A prospective study was performed on 30 consecutive active people who underwent ACL reconstruction with this technique by two surgeons between september2004 and march2007 (mean follow-up 15.2 months. Results were evaluated by an independent examiner using radiography, subjective and objective evaluation. Assessment using the IKDC knee scoring revealed 92% of the patients with a normal or nearly normal knee joint. Lysholm's score was 63.6(40- 86 preoperatively and 91.88(73-100 at the latest follow up (P < 0.005. No patient complained of instability at latest follow up. The quadriceps muscle showed mild atrophy at 3 and 6 months and at final follow-up. Five Patients complained of anterior knee pain and had a positive kneeling test. We found no graft displacement on follow up radiographs. All cases showed radiological evidence of graft osteointegration at last follow up. Our results show that press-fit fixation of trapezoidal bone graft in femoral tunnel is a simple, reliable, and cost-effective alternative for ACL recon-struction using bone-patellar tendon-bone graft.

Early humoral-mediated graft injuries in ABO-incompatible kidney transplantation in human beings.

Science.gov (United States)

Sekijima, M; Shimizu, A; Ishii, Y; Kudo, S; Horita, S; Nakajima, I; Fuchinoue, S; Teraoka, S

2010-04-01

Acute humoral rejection is the most important risk factor for early graft loss in ABO-incompatible (ABO-i) renal transplantation (RTx) and is present from the early period after RTx. However, the characteristics of early humoral-mediated graft injury are pathologically uncertain. To analyze tissue from 10 protocol graft biopsies performed in 10 patients within 30 days post-RTx to clarify the pathologic features of early humoral-mediated graft injuries in ABO-i RTx. Pathologic findings were examined using light and electron microscopy and immunofluorescence studies for C4d. Protocol biopsies were performed within 30 days after RTx in the absence of an episode of dysfunction (creatinine concentration 1.21-1.81 mg/dL). The immunofluorescence study demonstrated C4d deposition in peritubular and glomerular capillaries. Acute glomerulitis with infiltration of mononuclear cells and neutrophils was observed in 3 patients. Furthermore, glomerulitis was accompanied by endothelial cell injuries, widening of subendothelial spaces with a double-contoured glomerular basement membrane, and mesangiolysis. In ABO-i RTx, early humoral-mediated graft injuries were observed in approximately 30% of patients despite normal graft function. They were characterized by C4d deposition and glomerular capillary injury. These findings suggest that renal glomeruli are the first site of graft injury by anti-A or anti-B blood type antibody with complement activation in ABO-i RTx.

The effect of monomer molecular weight on grafting reaction

International Nuclear Information System (INIS)

Wu Minghong; Ding Zhongli; Ma Zueteh

1995-01-01

In this paper, some condensed ethylene glycol acrylate monomers with different molecular weight being grafted to the PE film by means of pre-irradiation is reported. The effect of molecular weight of monomer on grafting reaction and the hydrophilicity of grafting sample have been discussed. The experimental results show: molar degrees of grafting decreased non-linearly with the increasement of molecular weight of monomer, the grafting reaction of polymer is greater effected by the swelling degree of PE film, the greater the swelling degree of grafting material, the higher the grating degree grafting is, the initial rate of grafting reaction decreased with the increasement of molecular weight of monomer. (author)

A simple and rapid method to graft hydroxyapatite on carbon nanotubes

International Nuclear Information System (INIS)

Neelgund, Gururaj M.; Olurode, Kehinde; Luo Zhiping; Oki, Aderemi

2011-01-01

Herein a simple and effective approach is introduced to functionalize single walled carbon nanotubes (SWCNTs) by in-situ grafting of hydroxyapatite (HA). The pristine SWCNTs were chemically activated through introduction of carboxylic groups on their surfaces by refluxing in the mixture of H 2 SO 4 and HNO 3 . The resulting carboxylated SWCNTs were further utilized for grafting of HA. The Fourier transform infrared and Raman spectroscopic studies demonstrated the formation of HA and its grafting over SWCNTs. The phase composition of HA and existence Ca 2+ and PO 4 3- ions were studied using X-ray diffraction and energy dispersive X-ray analyses, respectively. The surface morphology of functionalized SWCNTs was analyzed using scanning electron microscopy and transmission electron microscopy. Thermogravimetric analysis confirmed the existence of HA on SWCNTs by exhibiting different thermogram for pure HA and functionalized SWCNTs. Overall, this method produced uniform grafting of low crystalline HA on carboxylated SWCNTs with strong interfacial bonding. - Graphical abstract: A facile approach is demonstrated for effective functionalization of single walled carbon nanotubes (SWCNTs) by in-situ grafting of hydroxyapatite (HA) to improve hydrophilicity and biocompatibility of SWCNTs. This method produced uniform grafting of low crystalline HA on carboxylated SWCNTs with strong interfacial bonding. Research highlights: → This method is facile and effective to graft HA on SWCNTs. → As f-SWCNTs is a promising biomaterial to use without any further processing → This technique is economic, easy to repeat and can be optimized for mass production. → Ratio of Ca to P in f-SWCNTs was 1.65, which is near to ratio present in bone tissue.

A simple and rapid method to graft hydroxyapatite on carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Neelgund, Gururaj M.; Olurode, Kehinde [Department of Chemistry, Prairie View A and M University, Prairie View, TX 77446 (United States); Luo Zhiping [Microscopy and Imaging Center, Materials Science and Engineering, Texas A and M University, College Station TX 77843 (United States); Oki, Aderemi, E-mail: aroki@pvamu.edu [Department of Chemistry, Prairie View A and M University, Prairie View, TX 77446 (United States)

2011-10-10

Herein a simple and effective approach is introduced to functionalize single walled carbon nanotubes (SWCNTs) by in-situ grafting of hydroxyapatite (HA). The pristine SWCNTs were chemically activated through introduction of carboxylic groups on their surfaces by refluxing in the mixture of H{sub 2}SO{sub 4} and HNO{sub 3}. The resulting carboxylated SWCNTs were further utilized for grafting of HA. The Fourier transform infrared and Raman spectroscopic studies demonstrated the formation of HA and its grafting over SWCNTs. The phase composition of HA and existence Ca{sup 2+} and PO{sub 4}{sup 3-} ions were studied using X-ray diffraction and energy dispersive X-ray analyses, respectively. The surface morphology of functionalized SWCNTs was analyzed using scanning electron microscopy and transmission electron microscopy. Thermogravimetric analysis confirmed the existence of HA on SWCNTs by exhibiting different thermogram for pure HA and functionalized SWCNTs. Overall, this method produced uniform grafting of low crystalline HA on carboxylated SWCNTs with strong interfacial bonding. - Graphical abstract: A facile approach is demonstrated for effective functionalization of single walled carbon nanotubes (SWCNTs) by in-situ grafting of hydroxyapatite (HA) to improve hydrophilicity and biocompatibility of SWCNTs. This method produced uniform grafting of low crystalline HA on carboxylated SWCNTs with strong interfacial bonding. Research highlights: {yields} This method is facile and effective to graft HA on SWCNTs. {yields} As f-SWCNTs is a promising biomaterial to use without any further processing {yields} This technique is economic, easy to repeat and can be optimized for mass production. {yields} Ratio of Ca to P in f-SWCNTs was 1.65, which is near to ratio present in bone tissue.

A multilayered polyurethane foam technique for skin graft immobilization.

Science.gov (United States)

Nakamura, Motoki; Ito, Erika; Kato, Hiroshi; Watanabe, Shoichi; Morita, Akimichi

2012-02-01

Several techniques are applicable for skin graft immobilization. Although the sponge dressing is a popular technique, pressure failure near the center of the graft is a weakness of the technique that can result in engraftment failure. To evaluate the efficacy of a new skin graft immobilization technique using multilayered polyurethane foam in vivo and in vitro. Twenty-six patients underwent a full-thickness skin graft. Multiple layers of a hydrocellular polyurethane foam dressing were used for skin graft immobilization. In addition, we created an in vitro skin graft model that allowed us to estimate immobilization pressure at the center and edges of skin grafts of various sizes. Overall mean graft survival was 88.9%. In the head and neck region (19 patients), mean graft survival was 93.6%. Based on the in vitro outcomes, this technique supplies effective pressure (skin graft. This multilayered polyurethane foam dressing is simple, safe, and effective for skin graft immobilization. © 2011 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.

[An experimental study of the healing of velour grafts].

Science.gov (United States)

Kobayashi, O

1986-02-01

An experimental study of implantation of velour grafts in the abdominal aorta or the external iliac artery of dogs was conducted with the object of evaluating the type of velour surface best fit for small-caliber artery implantation. Velour grafts measuring 4mm in diameter with differing velour surfaces were used as materials. Velour grafts now available on the market differ not only in velour surface but also in structure, notably in porosity and wall thickness. Hence each of the grafts used was reversed (i.e. inside out) and thus new grafts were prepared. These grafts were considered most suitable for making a comparative study of the effects of velour surface on healing. Macroscopic and histological findings revealed that each graft was good healing with the rate of patency as high as 84 percent. However, like Vasculour-D grafts, crimped grafts which preserve the crimp after implantation was significantly thicker at the internal valley than other grafts. Based on the findings of this experimental study non-crimped velour grafts were considered to be best fit for small-caliber artery implantation.

Graft Copolymerization Of Methyl Methacrylate Onto Agave Cellulose

International Nuclear Information System (INIS)

Noor Afizah Rosli; Ishak Ahmad; Ibrahim Abdullah; Farah Hannan Anuar

2014-01-01

The grafting polymerization of methyl methacrylate (MMA) and Agave cellulose was prepared and the grafting reaction conditions were optimized by varying the reaction time and temperature, and ratio of monomer to cellulose. The resulting graft copolymers were characterized by Fourier transform infrared, X-ray diffraction analysis, thermogravimetric analysis, and scanning electron microscopy (SEM). The experimental results showed that the optimal conditions were at a temperature of 45 degree Celsius for 90 min with ratio monomer to cellulose at 1:1 (g/ g). An additional peak at 1738 cm -1 which was attributed to the C=O of ester stretching vibration of poly(methyl methacrylate), appeared in the spectrum of grafted Agave cellulose. A slight decrease of crystallinity index upon grafting was found from 0.74 to 0.68 for cellulose and grafted cellulose, respectively. Grafting of MMA onto cellulose enhanced its thermal stability and SEM observation further furnished evidence of grafting MMA onto Agave cellulose with increasing cellulose diameter and surface roughness. (author)

Grafted Cellulose Based Adsorbents for Selective Separation Purposes

Energy Technology Data Exchange (ETDEWEB)

Takacs, E; Wojnarovits, L [Institute of Isotopes, Hungarian Academy of Sciences, Budapest (Hungary)

2012-09-15

The effect of high energy ionizing radiation on cotton-cellulose was studied. It was found that degradation of cellulose started at low doses, below 5 kGy, resulting in decrease in the degree of polymerization. However, the mechanical properties of cotton-cellulose samples only slightly changed with the dose up to 40 kGy. Acrylate type monomers were successfully grafted to cellulose by mutual and by pre-irradiation grafting technique. With both techniques the grafting yield increased with increasing dose and monomer concentration. In the case of pre-irradiation grafting the increase in grafting time also resulted in an increase in grafting percentage. Cotton-cellulose was functionalized using pre-irradiation grafting (PIG) and simultaneous grafting (SG) of glycidyl methacrylate (GMA). The adsorption properties of this material were further enhanced by {beta}-cyclodextrin (CD) immobilization. This molecule is known for its unique ability to form inclusion complexes among others with aromatic compounds like phenols, pesticide, dyes, etc. (author)

A new method for immobilization of biomolecules using preirradiation grafting at low temperature

International Nuclear Information System (INIS)

Liang Chang Dong; Hoffman, A.S.

1986-01-01

A new method of biomolecule immobilization is described in which a monomer-conjugated enzyme (asparaginase, Asp) is grafted together with free monomer (acrylamide, AAm) onto a cellulose sheet which had been preirradiated in a 60 Co source. The preirradiation and grafting steps are carried out in air at - 78 0 C and in vacuum at 0 0 C respectively. The grafting is probably caused by trapped radicals. The immobilized enzyme retains significant activity and is stable to storage. The technique is applicable to immobilization of a wide variety of biomolecules, such as enzymes, antibodies and drugs. The products may be used for therapeutic or diagnostic applications. (author)

MRI of double-bundle ACL reconstruction: evaluation of graft findings

Energy Technology Data Exchange (ETDEWEB)

Kiekara, Tommi; Paakkala, Antti [Tampere University Hospital, Medical Imaging Centre, Tampere (Finland); Jaervelae, Timo [Sports Clinic and Hospital Mehilaeinen, Tampere (Finland); Huhtala, Heini [University of Tampere, School of Health Sciences, Tampere (Finland)

2012-07-15

To demonstrate the magnetic resonance imaging (MRI) findings of double-bundle (DB) anterior cruciate ligament (ACL) reconstruction grafts. Sixty-six patients with DB ACL reconstruction were evaluated with MRI 2 years postoperatively. Graft thickness was measured separately by two musculoskeletal radiologists. The MRI findings of graft disruption, signal intensity (SI) changes, cystic degeneration, arthrofibrosis, and impingement were analyzed. The statistical significance of the association between MRI findings was calculated. The mean anteromedial (AM) graft thickness was reduced 9% and the mean posterolateral (PL) graft thickness was reduced 18% from the original graft thickness. Disruption was seen in 3% of AM grafts and 6% of PL grafts and a partial tear in 8 and 23%, respectively. Both grafts were disrupted in 3% of patients. Increased SI was seen in 14% of intact AM grafts and in 60% of partially torn AM grafts (p = 0.032). In PL grafts the increased SI was seen in 51% of the intact grafts and in 93% of the partially torn grafts (p = 0.005). Cystic degeneration was seen in 8% of AM grafts and in 5% of PL grafts. Diffuse arthrofibrosis was seen in 5% of patients and a localized cyclops lesion in 3% of patients. Impingement of the AM graft was seen in 8% of patients. Both grafts were disrupted in 3% of patients. Also, the frequencies of other complications were low. The use of orthogonal sequences in the evaluation of the PL graft SI seems to cause volume-averaging artefacts. (orig.)

Post radiation grafting of vinyl acetate onto low density polyethylene films: preparation and properties of membrane

International Nuclear Information System (INIS)

Dessouki, A.M.

1987-01-01

Reverse osmosis membranes were prepared by the post radiation grafting of vinyl acetate onto low density polyethylene films. The factors affecting the grafting process such as radiation dose, monomer concentration and temperature on the grafting yield were studied. It was found that the dependence of the grafting rate on radiation intensity and monomer concentration was found to be of 0.64 and 1.4 order, respectively. The activation energy for this grafting system was calculated and found to be 4.45 kcal/mol above 30 0 C. Some properties of the grafted films such as specific electric resistance, water uptake, mechanical properties and thermal and chemical stability were investigated. An improvement in these properties was observed which makes possible the use of these membranes in some practical applications. The use of such membranes for reverse osmosis desalination of saline water was tested. The effect of operating time, degree of grafting and applied pressure on the water flux and salt rejection were determined. The results showed salt rejection percent over 90% and a reasonable water flux. A suitable degree of grafting of the membrane was determined as well as the optimum applied pressure. (author)

Designer interface peptide grafts target estrogen receptor alpha dimerization

International Nuclear Information System (INIS)

Chakraborty, S.; Asare, B.K.; Biswas, P.K.; Rajnarayanan, R.V.

2016-01-01

The nuclear transcription factor estrogen receptor alpha (ERα), triggered by its cognate ligand estrogen, regulates a variety of cellular signaling events. ERα is expressed in 70% of breast cancers and is a widely validated target for anti-breast cancer drug discovery. Administration of anti-estrogen to block estrogen receptor activation is still a viable anti-breast cancer treatment option but anti-estrogen resistance has been a significant bottle-neck. Dimerization of estrogen receptor is required for ER activation. Blocking ERα dimerization is therefore a complementary and alternative strategy to combat anti-estrogen resistance. Dimer interface peptide “I-box” derived from ER residues 503–518 specifically blocks ER dimerization. Recently using a comprehensive molecular simulation we studied the interaction dynamics of ERα LBDs in a homo-dimer. Based on this study, we identified three interface recognition peptide motifs LDKITDT (ERα residues 479–485), LQQQHQRLAQ (residues 497–506), and LSHIRHMSNK (residues 511–520) and reported the suitability of using LQQQHQRLAQ (ER 497–506) as a template to design inhibitors of ERα dimerization. Stability and self-aggregation of peptide based therapeutics poses a significant bottle-neck to proceed further. In this study utilizing peptide grafted to preserve their pharmacophoric recognition motif and assessed their stability and potential to block ERα mediated activity in silico and in vitro. The Grafted peptides blocked ERα mediated cell proliferation and viability of breast cancer cells but did not alter their apoptotic fate. We believe the structural clues identified in this study can be used to identify novel peptidometics and small molecules that specifically target ER dimer interface generating a new breed of anti-cancer agents. - Highlights: • Designer peptide grafts retain core molecular recognition motif during MD simulations. • Designer peptide grafts with Poly-ALA helix form stable

Designer interface peptide grafts target estrogen receptor alpha dimerization

Energy Technology Data Exchange (ETDEWEB)

Chakraborty, S. [Laboratory of Computational Biophysics & Bioengineering, Department of Physics, Tougaloo College, Tougaloo, MS 39174 (United States); Asare, B.K. [Department of Pharmacology and Toxicology, University of Buffalo, Buffalo, NY 14214 (United States); Biswas, P.K., E-mail: pbiswas@tougaloo.edu [Laboratory of Computational Biophysics & Bioengineering, Department of Physics, Tougaloo College, Tougaloo, MS 39174 (United States); Rajnarayanan, R.V., E-mail: rajendra@buffalo.edu [Department of Pharmacology and Toxicology, University of Buffalo, Buffalo, NY 14214 (United States)

2016-09-09

The nuclear transcription factor estrogen receptor alpha (ERα), triggered by its cognate ligand estrogen, regulates a variety of cellular signaling events. ERα is expressed in 70% of breast cancers and is a widely validated target for anti-breast cancer drug discovery. Administration of anti-estrogen to block estrogen receptor activation is still a viable anti-breast cancer treatment option but anti-estrogen resistance has been a significant bottle-neck. Dimerization of estrogen receptor is required for ER activation. Blocking ERα dimerization is therefore a complementary and alternative strategy to combat anti-estrogen resistance. Dimer interface peptide “I-box” derived from ER residues 503–518 specifically blocks ER dimerization. Recently using a comprehensive molecular simulation we studied the interaction dynamics of ERα LBDs in a homo-dimer. Based on this study, we identified three interface recognition peptide motifs LDKITDT (ERα residues 479–485), LQQQHQRLAQ (residues 497–506), and LSHIRHMSNK (residues 511–520) and reported the suitability of using LQQQHQRLAQ (ER 497–506) as a template to design inhibitors of ERα dimerization. Stability and self-aggregation of peptide based therapeutics poses a significant bottle-neck to proceed further. In this study utilizing peptide grafted to preserve their pharmacophoric recognition motif and assessed their stability and potential to block ERα mediated activity in silico and in vitro. The Grafted peptides blocked ERα mediated cell proliferation and viability of breast cancer cells but did not alter their apoptotic fate. We believe the structural clues identified in this study can be used to identify novel peptidometics and small molecules that specifically target ER dimer interface generating a new breed of anti-cancer agents. - Highlights: • Designer peptide grafts retain core molecular recognition motif during MD simulations. • Designer peptide grafts with Poly-ALA helix form stable

Double-layered collagen graft to the radial forearm free flap donor sites without skin graft.

Science.gov (United States)

Park, Tae-Jun; Kim, Hong-Joon; Ahn, Kang-Min

2015-12-01

Radial forearm free flap is the most reliable flap for intraoral soft tissue reconstruction after cancer ablation surgery. However, unesthetic scar of the donor site and the need for a second donor site for skin graft are major disadvantages of the forearm flap. The purpose of this study was to report the clinical results of double-layered collagen graft to the donor site of the forearm free flap without skin graft. Twenty-two consecutive patients who underwent oral cancer ablation and forearm reconstruction between April 2010 and November 2013 were included in this study. Male to female ratio was 12:10, and average age was 61.0 years old (27-84). Double-layered collagen was grafted to the donor site of the forearm free flap and healed for secondary intention. Upper silicone had been trimmed at the periphery during secondary intention, and dry dressing was used. Postoperative scar healing and esthetic results and function were evaluated. An average follow-up period was 34.9 months. The scar area was decreased to 63.9 % in average. The complete healing was obtained between 1.5 and 3 months according to the defect size. There was no functional defect or impairment 3 months after operation. All patients were satisfied with the esthetic results. Three patients died of recurred cancer. Double-layered collagen graft was successfully performed in this study. Without the thigh skin graft, patients had experienced less painful postoperative healing periods and discomfort.

Covalent immobilization of lysozyme onto woven and knitted crimped polyethylene terephthalate grafts to minimize the adhesion of broad spectrum pathogens

International Nuclear Information System (INIS)

Al Meslmani, Bassam M.; Mahmoud, Gihan F.; Leichtweiß, Thomas; Strehlow, Boris; Sommer, Frank O.; Lohoff, Michael D.; Bakowsky, Udo

2016-01-01

Graft-associated infections entirely determine the short-term patency of polyethylene terephthalate PET cardiovascular graft. We attempted to enzymatically inhibit the initial bacterial adhesion to PET grafts using lysozyme. Lysozyme was covalently immobilized onto woven and knitted forms of crimped PET grafts by the end-point method. Our figures of merit revealed lysozyme immobilization yield of 15.7 μg/cm"2, as determined by the Bradford assay. The activity of immobilized lysozyme on woven and knitted PET manifested 58.4% and 55.87% using Micrococcus lysodeikticus cells, respectively. Noteworthy, the adhesion of vein catheter-isolated Staphylococcus epidermidis decreased by 6- to 8-folds and of Staphylococcus aureus by 11- to 12-folds, while the Gram-negative Escherichia coli showed only a decrease by 3- to 4-folds. The anti-adhesion efficiency was specific for bacterial cells and no significant effect was observed on adhesion and growth of L929 cells. In conclusion, immobilization of lysozyme onto PET grafts can inhibit the graft-associated infection. - Highlights: • Lysozyme was covalently immobilized on crimped polyethylene terephthalate (PET). • The activity of immobilized lysozyme was meaningfully reduced. • The maintained activity significantly declined the adhesion of Gram-positive stains. • The enzymatic anti-adhesion efficiency reported lesser extent against Gram-negative. • The anti-bacterial activity displayed no significant effect on cells compatibility.

Covalent immobilization of lysozyme onto woven and knitted crimped polyethylene terephthalate grafts to minimize the adhesion of broad spectrum pathogens

Energy Technology Data Exchange (ETDEWEB)

Al Meslmani, Bassam M., E-mail: almeslmanib@yahoo.com [Department of Pharmaceutical Technology and Biopharmaceutics, Marburg University, Ketzerbach 63, 35037 Marburg (Germany); Mahmoud, Gihan F., E-mail: mahmoudg@staff.uni-marburg.de [Department of Pharmaceutical Technology and Biopharmaceutics, Marburg University, Ketzerbach 63, 35037 Marburg (Germany); Department of Pharmaceutics and Industrial Pharmacy, Helwan University, Ain Helwan, 11795 Cairo (Egypt); Leichtweiß, Thomas, E-mail: Thomas.Leichtweiss@phys.Chemie.uni-giessen.de [Institute of Physical Chemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen (Germany); Strehlow, Boris, E-mail: strehlo4@staff.uni-marburg.de [Department of Pharmaceutical Technology and Biopharmaceutics, Marburg University, Ketzerbach 63, 35037 Marburg (Germany); Sommer, Frank O., E-mail: sommerf@med.uni-marburg.de [Institute for Medical Microbiology and Hospital Hygiene, Marburg University, Hans Meerwein Str 2, 35032 Marburg (Germany); Lohoff, Michael D., E-mail: lohoff@med.uni-marburg.de [Institute for Medical Microbiology and Hospital Hygiene, Marburg University, Hans Meerwein Str 2, 35032 Marburg (Germany); Bakowsky, Udo, E-mail: ubakowsky@aol.com [Department of Pharmaceutical Technology and Biopharmaceutics, Marburg University, Ketzerbach 63, 35037 Marburg (Germany)

2016-01-01

Graft-associated infections entirely determine the short-term patency of polyethylene terephthalate PET cardiovascular graft. We attempted to enzymatically inhibit the initial bacterial adhesion to PET grafts using lysozyme. Lysozyme was covalently immobilized onto woven and knitted forms of crimped PET grafts by the end-point method. Our figures of merit revealed lysozyme immobilization yield of 15.7 μg/cm{sup 2}, as determined by the Bradford assay. The activity of immobilized lysozyme on woven and knitted PET manifested 58.4% and 55.87% using Micrococcus lysodeikticus cells, respectively. Noteworthy, the adhesion of vein catheter-isolated Staphylococcus epidermidis decreased by 6- to 8-folds and of Staphylococcus aureus by 11- to 12-folds, while the Gram-negative Escherichia coli showed only a decrease by 3- to 4-folds. The anti-adhesion efficiency was specific for bacterial cells and no significant effect was observed on adhesion and growth of L929 cells. In conclusion, immobilization of lysozyme onto PET grafts can inhibit the graft-associated infection. - Highlights: • Lysozyme was covalently immobilized on crimped polyethylene terephthalate (PET). • The activity of immobilized lysozyme was meaningfully reduced. • The maintained activity significantly declined the adhesion of Gram-positive stains. • The enzymatic anti-adhesion efficiency reported lesser extent against Gram-negative. • The anti-bacterial activity displayed no significant effect on cells compatibility.

GRAFT TAKES OF TOMATO ON OTHER SOLANACEOUS PLANTS

Directory of Open Access Journals (Sweden)

ANDRÉ RICARDO ZEIST

2017-01-01

Full Text Available This paper aimed to assess tomato grafting on different solanaceous species through two grafting methods. Scions were cut from cultivar Santa Cruz Kada seedlings. A fully randomized experimental design was carried out with treatments in a 9 x 2 factorial scheme. As rootstocks, four accessions of mini - tomatoes (0224 - 53, RVTC 57, RVTC 20 and 6889 - 50 - Solanum lycopersicum L; two species of wild tomato ( Solanum habrochaites var hirsutum ‘PI - 127826’ and Solanum pennellii ‘LA716’; other two tomato species [ Solanum, cocona ( Solanum sessiliflorum and physalis ( Physalis peruviana ] and a control with cultivar Santa Cruz Kada (auto - graft rootstocks were used. In addition, two grafting methods were evaluated full cleft and approach graft. Fifteen days after grafting, plants were assessed for graft - take percentage; root length; plant height; leaf number; foliar area; root, stem and leaf dry matter; and ratio between shoot and root dry matter. Based on the results, we may state rootstock and grafting interaction had effect on both graft - take rate and plant development. Overall, the studied plants should be recommended as rootstock, except for 6889 - 50 mini - tomato ( S. lycopersicum L. and S. pennellii . Full cleft grafting was most suitable for cocona and physalis, while the approach method showed better results for the mini - tomato accessions 0224 - 53, RVTC 57 and RVTC 20, as well as for S. habrochaites .

Phase transition of pNIPAM grafted on plasma-activated PEO monitored in-situ by quartz crystal microbalance

Energy Technology Data Exchange (ETDEWEB)

Heinz, P; Bretagnol, F; Mannelli, I; Gillil, D; Rauscher, H; Rossi, F [European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21020 Ispra (Vatican City State, Holy See,) (Italy)], E-mail: hubert.rauscher@jrc.it

2008-03-15

Thermoresponsive poly(N-isopropylacrylamide) layers were grafted on plasma-activated poly(ethylene oxide)-like substrate. Analysis by ToF-SIMS confirmed the presence of a pNIPAM film, which shows a phase transition temperature at 28 - 32 deg. C with hysteresis, as determined in-situ by quartz crystal microbalance. During the transition, the frequency of the pNIPAM coated quartz sensor exhibits a pronounced and unexpected minimum while the dissipation changes monotonously. This peculiar behaviour is explained by temporary formation of water-rich regions, which may cause delayed release and uptake of water during the collapse and re-swelling of the layer.

Phase transition of pNIPAM grafted on plasma-activated PEO monitored in-situ by quartz crystal microbalance

International Nuclear Information System (INIS)

Heinz, P; Bretagnol, F; Mannelli, I; Gillil, D; Rauscher, H; Rossi, F

2008-01-01

Thermoresponsive poly(N-isopropylacrylamide) layers were grafted on plasma-activated poly(ethylene oxide)-like substrate. Analysis by ToF-SIMS confirmed the presence of a pNIPAM film, which shows a phase transition temperature at 28 - 32 deg. C with hysteresis, as determined in-situ by quartz crystal microbalance. During the transition, the frequency of the pNIPAM coated quartz sensor exhibits a pronounced and unexpected minimum while the dissipation changes monotonously. This peculiar behaviour is explained by temporary formation of water-rich regions, which may cause delayed release and uptake of water during the collapse and re-swelling of the layer

Lycopene and flesh colour differences in grafted and non-grafted watermelon

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Fekete D.

2015-01-01

Full Text Available The experiment was carried out in three regions in Hungary (Jászszentandrás, Cece, Újkígyós in 2013 to determine the fruit quality of grafted watermelon (Citrullus lanatus Thunb.. The “RX 467” seedless watermelon variety was grafted on two commercial rootstocks “FR STRONG” [Lagenaria siceraria (Mol. Standl.] and “RS 841” (Cucurbita maxima Duchesne × Cucurbita moschata Duchesne. The lycopene and flesh colours are important quality characteristics even of the selfrooted and grafted watermelon. Some differences can be attributed to different environments, technological methods and to the type of rootstockscion combination. Lycopene is a strong antioxidant; therefore, we considered to examine the content change. Regardless of growing location, the lycopene concentration and the chroma (C* showed the best result in the case of interspecific rootstock. The result also showed that in two regions (Jászszentandrás, Cece we can find negative correlation between the lycopene concentration and the L* value of the flesh colour.

Nitrite enhances liver graft protection against cold ischemia ...

African Journals Online (AJOL)

Amani Cherif-Sayadi

2017-03-30

Mar 30, 2017 ... cold ischemia reperfusion injury through a NOS ... oxidation and lipid peroxidation remained at low levels in both nitrite-treated groups when ... liver graft preservation [15]. ... nitrite activity is dependent on NO production but .... LiversT rat (n = 6) were flushed and preserved in IGL-1 solution ..... The nitrate-.

Influence of polymer architecture on antigens camouflage, CD47 protection and complement mediated lysis of surface grafted red blood cells.

Science.gov (United States)

Chapanian, Rafi; Constantinescu, Iren; Rossi, Nicholas A A; Medvedev, Nadia; Brooks, Donald E; Scott, Mark D; Kizhakkedathu, Jayachandran N

2012-11-01

Hyperbranched polyglycerol (HPG) and polyethylene glycol (PEG) polymers with similar hydrodynamic sizes in solution were grafted to red blood cells (RBCs) to investigate the impact of polymer architecture on the cell structure and function. The hydrodynamic sizes of polymers were calculated from the diffusion coefficients measured by pulsed field gradient NMR. The hydration of the HPG and PEG was determined by differential scanning calorimetry analyses. RBCs grafted with linear PEG had different properties compared to the compact HPG grafted RBCs. HPG grafted RBCs showed much higher electrophoretic mobility values than PEG grafted RBCs at similar grafting concentrations and hydrodynamic sizes indicating differences in the structure of the polymer exclusion layer on the cell surface. PEG grafting impacted the deformation properties of the membrane to a greater degree than HPG. The complement mediated lysis of the grafted RBCs was dependent on the type of polymer, grafting concentration and molecular size of grafted chains. At higher molecular weights and graft concentrations both HPG and PEG triggered complement activation. The magnitude of activation was higher with HPG possibly due to the presence of many hydroxyl groups per molecule. HPG grafted RBCs showed significantly higher levels of CD47 self-protein accessibility than PEG grafted RBCs at all grafting concentrations and molecular sizes. PEG grafted polymers provided, in general, a better shielding and protection to ABO and minor antigens from antibody recognition than HPG polymers, however, the compact HPGs provided greater protection of certain antigens on the RBC surface. Our data showed that HPG 20 kDa and HPG 60 kDa grafted RBCs exhibited properties that are more comparable to the native RBC than PEG 5 kDa and PEG 10 kDa grafted RBCs of comparable hydrodynamic sizes. The study shows that small compact polymers such as HPG 20 kDa have a greater potential in the generation of functional RBC for therapeutic

Fixation of tibial plateau fractures with synthetic bone graft versus natural bone graft: a comparison study.

LENUS (Irish Health Repository)

Ong, J C Y

2012-06-01

The goal of this study was to determine differences in fracture stability and functional outcome between synthetic bone graft and natural bone graft with internal fixation of tibia plateau metaphyseal defects.

Novel anterior cruciate ligament graft fixation device reduces slippage

Directory of Open Access Journals (Sweden)

Lopez MJ

2013-05-01

Full Text Available Mandi J Lopez,1 Allen Borne,2 W Todd Monroe,3 Prakash Bommala,1 Laura Kelly,1 Nan Zhang11Laboratory for Equine and Comparative Orthopedic Research, Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, 2Louisiana State University, New Orleans Health Sciences Center, School of Medicine, New Orleans, 3Department of Biological and Agricultural Engineering, Agricultural Center, Louisiana State University, Baton Rouge, LA, USAAbstract: Clinically significant laxity occurs in 10%–30% of knees after anterior cruciate ligament reconstruction. Graft slippage and tension loss at the hamstring graft tibial fixation site during and after reconstruction surgery contribute to postoperative joint laxity and are detrimental to long-term knee stability and graft properties. Limiting graft slippage will reduce associated complications. We sought to compare the in vitro mechanical properties and in vivo joint stabilization, postoperative limb use, and graft incorporation of the novel GraftGrab™ (GG device designed to reduce hamstring graft tibial fixation slippage with the commercially available bioabsorbable Bio-Post™ and spiked washer (BP. Mechanical testing was performed on canine tibia-hamstring graft constructs to quantify initial fixation properties. In vivo joint stabilization, postoperative limb use and graft incorporation of hamstring graft reconstructions were determined in a canine model. Outcomes included tibial translation and ground reaction forces preoperatively and 4 and 8 weeks postoperatively, three-dimensional graft and bone tunnel dimensions at the latter two time points, and graft-bone microstructure, as well as mechanical properties 8 weeks after implantation. Immediately after fixation, all grafts slipped from the BP constructs versus about 30% of GG constructs. In vivo limb use remained low, and tibial translation increased with time in the BP cohort. These results together

Low mannose-binding lectin serum levels are associated with reduced kidney graft survival

DEFF Research Database (Denmark)

Bay, Jakob Thaning; Sørensen, Søren S; Hansen, Jesper M

2013-01-01

Activation of the complement system is initiated by the alternative, the classical, or the lectin pathway. As the complement system is involved in the pathophysiology of graft rejection after kidney transplantation, we investigated the possible role of mannose-binding lectin in kidney transplanta...... immunity in maintaining kidney graft survival, but these are probably overruled by HLA immunization.Kidney International advance online publication, 21 November 2012; doi:10.1038/ki.2012.373....

Graft infections after surgical aortic reconstructions

OpenAIRE

Berger, P.

2015-01-01

Prosthetic vascular grafts are frequently used to reconstruct (part) of the aorta. Every surgical procedure caries a certain risk for infection and when a prosthetic aortic graft is implanted, this may lead to an aortic graft infection (AGI). Endovascular techniques have gradually replaced open surgical reconstructions as first line of treatment for aorto-iliac diseases. Nowadays, open reconstructions are primarily reserved for patients unsuitable for endovascular reconstructions or for redo ...

Corneal graft reversal: Histopathologic report of two cases

OpenAIRE

Qahtani, Abdullah A.; Alkatan, Hind M.

2014-01-01

Graft reversal is a rare cause for failed PKP. In this case report we are presenting 2 graft failure cases in which the corneal grafts were reversed unintentionally. The onset of signs of graft failure, however was variable. We have included their clinical course and the histopathologic findings of the removed corneal grafts. A total of 6 cases including ours have been reported so far. The aim of this report is to attract the attention of corneal surgeons to an additional rare cause for faile...

Graft Product for Autologous Peripheral Blood Stem Cell Transplantation Enhances Thrombin Generation and Expresses Procoagulant Microparticles and Tissue Factor.

Science.gov (United States)

Sidibe, Fatoumata; Spanoudaki, Anastasia; Vanneaux, Valerie; Mbemba, Elisabeth; Larghero, Jerome; Van Dreden, Patrick; Lotz, Jean-Pierre; Elalamy, Ismail; Larsen, Annette K; Gerotziafas, Grigoris T

2018-05-01

The beneficial effect of autologous peripheral blood stem cell transplantation (APBSCT) may be compromised by acute vascular complications related to hypercoagulability. We studied the impact of graft product on thrombin generation of normal plasma and the expression of tissue factor (TF) and procoagulant platelet-derived procoagulant microparticles (Pd-MPs) in samples of graft products. Graft products from 10 patients eligible for APBSCT were mixed with platelet-poor plasma (PPP) or platelet-rich plasma (PRP) from healthy volunteers and assessed for in vitro thrombin generation. In control experiments, thrombin generation was assessed in (1) PPP and PRP without any exogenous TF and/or procoagulant phospholipids, (2) PPP with the addition of TF (5 pM) and procoagulant phospholipids (4 μM), (3) in PRP with the addition of TF (5 pM). Graft products were assessed with Western blot assay for TF expression, with a specific clotting assay for TF activity and with flow cytometry assay for Pd-MPs. The graft product enhanced thrombin generation and its procoagulant activity was related to the presence of Pd-MPs and TF. The concentration of Pd-MPs in the graft product was characterized by a significant interindividual variability. The present study reveals the need for a thorough quality control of the graft products regarding their procoagulant potential.

Rule-based model of vein graft remodeling.

Directory of Open Access Journals (Sweden)

Minki Hwang

Full Text Available When vein segments are implanted into the arterial system for use in arterial bypass grafting, adaptation to the higher pressure and flow of the arterial system is accomplished thorough wall thickening and expansion. These early remodeling events have been found to be closely coupled to the local hemodynamic forces, such as shear stress and wall tension, and are believed to be the foundation for later vein graft failure. To further our mechanistic understanding of the cellular and extracellular interactions that lead to global changes in tissue architecture, a rule-based modeling method is developed through the application of basic rules of behaviors for these molecular and cellular activities. In the current method, smooth muscle cell (SMC, extracellular matrix (ECM, and monocytes are selected as the three components that occupy the elements of a grid system that comprise the developing vein graft intima. The probabilities of the cellular behaviors are developed based on data extracted from in vivo experiments. At each time step, the various probabilities are computed and applied to the SMC and ECM elements to determine their next physical state and behavior. One- and two-dimensional models are developed to test and validate the computational approach. The importance of monocyte infiltration, and the associated effect in augmenting extracellular matrix deposition, was evaluated and found to be an important component in model development. Final model validation is performed using an independent set of experiments, where model predictions of intimal growth are evaluated against experimental data obtained from the complex geometry and shear stress patterns offered by a mid-graft focal stenosis, where simulation results show good agreements with the experimental data.

Zwitterionic sulfobetaine-grafted poly(vinylidene fluoride) membrane with highly effective blood compatibility via atmospheric plasma-induced surface copolymerization.

Science.gov (United States)

Chang, Yung; Chang, Wan-Ju; Shih, Yu-Ju; Wei, Ta-Chin; Hsiue, Ging-Ho

2011-04-01

Development of nonfouling membranes to prevent nonspecific protein adsorption and platelet adhesion is critical for many biomedical applications. It is always a challenge to control the surface graft copolymerization of a highly polar monomer from the highly hydrophobic surface of a fluoropolymer membrane. In this work, the blood compatibility of poly(vinylidene fluoride) (PVDF) membranes with surface-grafted electrically neutral zwitterionic poly(sulfobetaine methacrylate) (PSBMA), from atmospheric plasma-induced surface copolymerization, was studied. The effect of surface composition and graft morphology, electrical neutrality, hydrophilicity and hydration capability on blood compatibility of the membranes were determined. Blood compatibility of the zwitterionic PVDF membranes was systematically evaluated by plasma protein adsorption, platelet adhesion, plasma-clotting time, and blood cell hemolysis. It was found that the nonfouling nature and hydration capability of grafted PSBMA polymers can be effectively controlled by regulating the grafting coverage and charge balance of the PSBMA layer on the PVDF membrane surface. Even a slight charge bias in the grafted zwitterionic PSBMA layer can induce electrostatic interactions between proteins and the membrane surfaces, leading to surface protein adsorption, platelet activation, plasma clotting and blood cell hemolysis. Thus, the optimized PSBMA surface graft layer in overall charge neutrality has a high hydration capability and the best antifouling, anticoagulant, and antihemolytic activities when comes into contact with human blood. © 2011 American Chemical Society

Vascularized fibular graft in infected tibial bone loss

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C Cheriyan Kovoor

2011-01-01

Full Text Available Background : The treatment options of bone loss with infections include bone transport with external fixators, vascularized bone grafts, non-vascularized autogenous grafts and vascularized allografts. The research hypothesis was that the graft length and intact ipsilateral fibula influenced hypertrophy and stress fracture. We retrospectively studied the graft hypertrophy in 15 patients, in whom vascularized fibular graft was done for post-traumatic tibial defects with infection. Materials and Methods : 15 male patients with mean age 33.7 years (range 18 - 56 years of post traumatic tibial bone loss were analysed. The mean bony defect was 14.5 cm (range 6.5 - 20 cm. The mean length of the graft was 16.7 cm (range 11.5 - 21 cm. The osteoseptocutaneous flap (bone flap with attached overlying skin flap from the contralateral side was used in all patients except one. The graft was fixed to the recipient bone at both ends by one or two AO cortical screws, supplemented by a monolateral external fixator. A standard postoperative protocol was followed in all patients. The hypertrophy percentage of the vascularized fibular graft was calculated by a modification of the formula described by El-Gammal. The followup period averaged 46.5 months (range 24 - 164 months. The Pearson correlation coefficient (r was worked out, to find the relationship between graft length and hypertrophy. The t-test was performed to find out if there was any significant difference in the graft length of those who had a stress fracture and those who did not and to find out whether there was any significant difference in hypertrophy with and without ipsilateral fibula union. The Chi square test was performed to identify whether there was any association between the stress fracture and the fibula union. Given the small sample size we have not used any statistical analysis to determine the relation between the percentage of the graft hypertrophy and stress fracture. Results : Graft

Visualization of a prosthetic vascular graft due to platelet contamination during 111Indium-labeled leukocyte scintigraphy

International Nuclear Information System (INIS)

Oates, E.; Ramberg, K.

1988-01-01

A prosthetic axillo-femoral bypass graft was visualized during 111 In-labeled leukocyte scintigraphy in a patient referred for possible abdominal abscess. The presence of significant cardiac blood-pool activity raised the possibility that this uptake was due to deposition of contaminating labeled platelets rather than labeled leukocytes. An analysis of a small sample of the patient's blood confirmed that the circulating activity was due to labeled platelets. Increased activity along prosthetic vascular grafts in patients undergoing 111 In-labeled leukocyte scintigraphy may be due to adherent platelet, and not indicative of infection

Autologous fat graft and bone marrow-derived mesenchymal stem cells assisted fat graft for treatment of Parry-Romberg syndrome.

Science.gov (United States)

Jianhui, Zhao; Chenggang, Yi; Binglun, Lu; Yan, Han; Li, Yang; Xianjie, Ma; Yingjun, Su; Shuzhong, Guo

2014-09-01

Progressive facial hemiatrophy, also called Parry-Romberg syndrome (PRS), is characterized by slowly progressive atrophy of one side of the face and primarily involves the subcutaneous tissue and fat. The restoration of facial contour and symmetry in patients affected by PRS still remains a challenge clinically. Fat graft is a promising treatment but has some shortcomings, such as unpredictability and low rate of graft survival due to partial necrosis. To obviate these disadvantages, fat graft assisted by bone marrow-derived mesenchymal stem cells (BMSCs) was used to treat PRS patients and the outcome was evaluated in comparison with the conventional treatment by autologous fat graft. Autologous fat graft was harvested by tumescent liposuction. Bone marrow-derived mesenchymal stem cells were then isolated by human Lymphocytes Separation Medium through density gradient centrifugation. Twenty-six patients were treated with autologous fat graft only (group A), whereas 10 other patients were treated with BMSC-assisted fat graft (group B). The Coleman technique was applied in all fat graft injections. The follow-up period was 6 to 12 months in this study, In group A, satisfactory outcome judged by symmetrical appearances was obtained with 1 injection in 12 patients, 2 injections in 8 patients, and 3 injections in 4 patients. However, the result of 1 patient was not satisfactory and 1 patient was overcorrected. In group B, 10 patients obtained satisfactory outcomes and almost reached symmetry by 1 injection. No complications (infection, hematoma, or subcutaneous mass) were observed. The results suggest that BMSC-assisted fat graft is effective and safe for soft tissue augmentation and may be superior to conventional lipoinjection. Additional study is necessary to further evaluate the efficacy of this technique.

Primary contraction of skin grafts: a porcine preliminary study

Directory of Open Access Journals (Sweden)

Alexander Bogdanov Berezovsky

2015-03-01

Full Text Available Aim: Skin grafting is a common clinical practice for plastic surgeons, yet primary contraction of these grafts is a neglected topic. This study was designed to investigate primary contraction and introduce the shape of skin graft as a possible factor that modifies primary contraction behavior, using porcine models. Methods: In the first series, full-thickness skin grafts (FTSGs and split-thickness skin grafts (STSGs were compared. In a second series, how the shape of the skin graft affected the degree of contraction was examined. Results: The mean percentage of FTSG shrinkage was 12.04%, and the median was 12.18%. The mean percentage of STSG shrinkage was 6.87%, and the median was 5%. Circle-shaped and square-shaped FTSGs showed mean/median graft shrinkage of 5.83%/6.93% and 4.15%/3.75%, respectively. In STSGs, the circle-shaped and square-shaped grafts had mean/median graft shrinkage of 1.07%/0% and 0.31%/0%, respectively. Conclusion: Our preliminary report revealed an expected greater shrinkage of FTSGs compared with STSGs. Furthermore, in a limited number of specimens, the shape of the skin graft seemed to affect the primary contraction of the STSGs.

Calcification of a Synthetic Renovascular Graft in a Child

Directory of Open Access Journals (Sweden)

D.S.T. Chong

Full Text Available : Introduction: Vascular grafts, especially in paediatric cases, need to be durable. Common failures such as thrombosis are well documented with research efforts directed towards them. However, there are lesser known causes of graft failure, such as graft calcification, and these also require further research focus. Report: A paediatric case is described in which a synthetic renovascular graft, implanted for mid-aortic syndrome, became calcified, necessitating surgical intervention to resolve graft malfunction. Significant calcification in the limb of a bifurcated polyethylene terephthalate graft was found to be the cause of resistant stenosis and refractory hypertension. Histology conducted on the explanted limb showed the presence of multinuclear giant cells, indicating a chronic foreign body response. Discussion: Calcification of vascular grafts is probably more common than previously recognised. Stenosis typically resistant to angioplasty may result in the long term and thus leading to surgical intervention. In young children, this is suboptimal as these grafts need to last throughout adulthood. Explanted prosthetic grafts should be sent to specialist registries such as that in Strasbourg to be optimally assessed so that contributory factors can be identified. Keywords: Renovascular graft, Paediatric, Calcification

Permeability of solutes through cellophanes grafted with vinyl monomers. II. Diffusion of potassium chloride through cellophanes grafted with acrylic acid

International Nuclear Information System (INIS)

Takigami, S.; Maeda, Y.; Nakamura, Y.

1979-01-01

The permeability behavior of potassium chloride through cellophane grafted with acrylic acid by a γ-irradiation method was studied by the theoretical equation derived from the phenomenological equation and compared with the results of Donnan membrane equilibrium. It was shown that the permeation of potassium chloride through the grafted cellophanes exhibited behavior typical of a polyionic membrane for grafts of more than 55% but depended on the permeability of both cellophane and graft regions for lower percents of grafting. It was found that the dominant factor affecting the permeation of potassium chloride was an effective concentration of fixed charge in the membrane. 5 figures, 2 tables

Evolution of shear stress, protein expression, and vessel area in an animal model of arterial dilatation in hemodialysis grafts

Science.gov (United States)

Misra, Sanjay; Fu, Alex A.; Misra, Khamal D.; Glockner, James F.; Mukhopadyay, Debabrata

2010-01-01

Purpose To evaluate the wall shear stress, protein expression of matrix metalloproteinases-2 (MMP-2), -9 (MMP-9), and the inhibitors (tissue inhibitor of matrix metalloproteinases-1 (TIMP-1), and -2 (TIMP-2)), and vessel area over time in a porcine model for hemodialysis polytetrafluoroethylene (PTFE) grafts. Materials and methods In 21 pigs, subtotal renal infarction was performed and 28 days later, a PTFE graft was placed to connect the carotid artery to the ipsilateral jugular vein. Phase contrast MR was used to measure blood flow and vessel area at 1, 3, 7, and 14 days after graft placement. Wall shear stress was estimated from Poiseuille’s law. Animals were sacrificed at day 3 (N=7), day 7 (N=7), and day 14 (N=7) and expression of MMP-2, MMP-9, TIMP-1, and TIMP-2 were determined at the grafted and control arteries. Results The mean wall shear stress of the grafted artery was higher than the control artery at all time points (P<0.05). It peaked by day 3 and decreased by days 7–14 as the vessel area nearly doubled. By days 7–14, there was a significant increase in active MMP-2 followed by a significant increase in pro and active MMP-9 by day 14 (P<0.05, grafted artery versus control). TIMP-1 expression peaked by day 7 and then decreased while TIMP-2 expression was decreased at days 7–14. Conclusions The wall shear stress of the grafted artery peaks by day 3 with increased MMP-2 activity by days 7–14 followed by pro and active MMP-9 by day 14 and the vessel area nearly doubled. PMID:20123196

Effects of cilostazol and k-134 on reconstructive surgery using prosthetic grafts in the abdominal aorta of beagle dogs.

Science.gov (United States)

Inoue, Yoshinori; Sugano, Norihide; Jibiki, Masatoshi; Kudo, Toshifumi; Iwai, Takehisa

2008-01-01

Problems associated with prosthetic graft replacement are stenosis at the anastomosis site and thrombus formation on the inner surface. Cilostazol is known to have antiplatelet activity and inhibit vascular smooth muscle cell proliferation and neointima thickening. A cilostazol derivative, (-)-6-[3-[3-cyclopropyl-3-[(1R,2R)-2-hydroxycyclohexyl]ureido]-propoxy]-2-(1H)-quinolinone (K-134), has more potent anti-platelet activity and anti-neointimal thickening activity than cilostazol in the in-vitro platelet aggregation and in-vivo anti-hyperplastic activity assay. The aim of this study was to investigate effects of cilostazol and K-134 on thrombus formation and neointimal thickening at the site of prosthetic graft replacement. Beagle dogs underwent infrarenal abdominal aortic resection with straight Dacron graft replacement, which were allocated to the control, cilostazol, and K-134 groups. Two dogs were dead without confirming the cause of death. After 6 months, all dogs were necropsied. All prosthetic grafts were patent in each group. Ratios of red thrombus to prosthetic graft area were 0.3+/-6.4%, and 3.3+/-4.5% in the cilostazol and K-134 groups, respectively, which were significant different from that in the control group (24.4+/-16.8%). However, no clear difference was seen among the 3 groups with respect to neointimal thickness (control group, 0.70+/-0.13 mm; cilostazol group, 0.59+/-0.14 mm; K-134 group, 0.67+/-0.14 mm). Cilostazol and K-134 significantly inhibited thrombus formation on the inner surface of the prosthetic graft at 6 months after graft replacement. Neointimal thickening on the inner surface was slight even in control-group animals, and the effects of cilostazol and K-134 on such thickening were unclear.

Studies on surface graft polymerization of acrylic acid onto PTFE film by remote argon plasma initiation

International Nuclear Information System (INIS)

Wang Chen; Chen Jierong

2007-01-01

The graft polymerization of acrylic acid (AAc) was carried out onto poly(tetrafluoroethylene) (PTFE) films that had been pretreated with remote argon plasma and subsequently exposed to oxygen to create peroxides. Peroxides are known to be the species responsible for initiating the graft polymerization when PTFE reacts with AAc. We chose different parameters of remote plasma treatment to get the optimum condition for introducing maximum peroxides (2.87 x 10 -11 mol/cm 2 ) on the surface. The influence of grafted reaction conditions on the grafting degree was investigated. The maximum grafting degree was 25.2 μg/cm 2 . The surface microstructures and compositions of the AAc grafted PTFE film were characterized with the water contact angle meter, Fourier-transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). Contact angle measurements revealed that the water contact angle decreased from 108 o to 41 o and the surface free energy increased from 22.1 x 10 -5 to 62.1 x 10 -5 N cm -1 by the grafting of the AAc chains. The hydrophilicity of the PTFE film surface was greatly enhanced. The time-dependent activity of the grafted surface was better than that of the plasma treated film

Grafting of phosphorylcholine functional groups on polycarbonate urethane surface for resisting platelet adhesion

Energy Technology Data Exchange (ETDEWEB)

Gao, Bin [School of Chemical Engineering and Technology, Tianjin University, Weijin Road 92, Tianjin 300072 (China); Feng, Yakai, E-mail: yakaifeng@hotmail.com [School of Chemical Engineering and Technology, Tianjin University, Weijin Road 92, Tianjin 300072 (China); Tianjin University-Helmholtz-Zentrum Geesthacht, Joint Laboratory for Biomaterials and Regenerative Medicine, Weijin Road 92, 300072 Tianjin (China); Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Weijin Road 92, Tianjin 300072 (China); Lu, Jian; Zhang, Li; Zhao, Miao; Shi, Changcan; Khan, Musammir [School of Chemical Engineering and Technology, Tianjin University, Weijin Road 92, Tianjin 300072 (China); Guo, Jintang [School of Chemical Engineering and Technology, Tianjin University, Weijin Road 92, Tianjin 300072 (China); Tianjin University-Helmholtz-Zentrum Geesthacht, Joint Laboratory for Biomaterials and Regenerative Medicine, Weijin Road 92, 300072 Tianjin (China)

2013-07-01

In order to improve the resistance of platelet adhesion on material surface, 2-methacryloyloxyethyl phosphorylcholine (MPC) was grafted onto polycarbonate urethane (PCU) surface via Michael reaction to create biomimetic structure. After introducing primary amine groups via coupling tris(2-aminoethyl)amine (TAEA) onto the polymer surface, the double bond of MPC reacted with the amino group to obtain MPC modified PCU. The modified surface was characterized by Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The results verified that MPC was grafted onto PCU surface by Michael reaction method. The MPC grafted PCU surface had a low water contact angle and a high water uptake. This means that the hydrophilic PC functional groups improved the surface hydrophilicity significantly. In addition, surface morphology of MPC grafted PCU film was imaged by atomic force microscope (AFM). The results showed that the grafted surface was rougher than the blank PCU surface. In addition, platelet adhesion study was evaluated by scanning electron microscopy (SEM) observation. The PCU films after treated with platelet-rich plasma demonstrated that much fewer platelets adhered to the MPC-grafted PCU surface than to the blank PCU surface. The antithrombogenicity of the MPC-grafted PCU surface was determined by the activated partial thromboplastin time (APTT). The result suggested that the MPC modified PCU may have potential application as biomaterials in blood-contacting and some subcutaneously implanted devices. - Highlights: • MPC was successfully grafted onto polycarbonate urethane surface via Michael reaction. • High concentration of PC functional groups on the surface via TAEA molecule • Biomimetic surface modification • The modified surface showed high hydrophilicity and anti-platelet adhesion.

Embryonic Cell Grafts in a Culture Model of Spinal Cord Lesion: Neuronal Relay Formation is Essential for Functional Regeneration

Directory of Open Access Journals (Sweden)

Anne Tscherter

2016-09-01

Full Text Available Presently there exists no cure for spinal cord injury. However, transplantation of embryonic tissue into spinal cord lesions resulted in axon outgrowth across the lesion site and some functional recovery, fostering hope for future stem cell therapies. Although in vivo evidence for functional recovery is given, the exact cellular mechanism of the graft support remains elusive: either the grafted cells provide a permissive environment for the host tissue to regenerate itself or the grafts actually integrate functionally into the host neuronal network reconnecting the separated spinal cord circuits. We tested the two hypotheses in an in vitro spinal cord lesion model that is based on propagation of activity between two rat organotypic spinal cord slices in culture. Transplantation of dissociated cells from E14 rat spinal cord or forebrain re-established the relay of activity over the lesion site and, thus, provoked functional regeneration. Combining patch-clamp recordings from transplanted cells with network activity measurements from the host tissue on multi-electrode arrays we here show that neurons differentiate from the grafted cells and integrate into the host circuits. Optogenetic silencing of neurons developed from transplanted embryonic mouse forebrain cells provides clear evidence that they replace the lost neuronal connections to relay and synchronize activity between the separated spinal cord circuits. In contrast, transplantation of neurospheres induced neither the differentiation of mature neurons from the grafts nor an improvement of functional regeneration. Together these findings suggest, that the formation of neuronal relays from grafted embryonic cells is essential to re-connect segregated spinal cord circuits.

Dynamic, nondestructive imaging of a bioengineered vascular graft endothelium.

Directory of Open Access Journals (Sweden)

Bryce M Whited

Full Text Available Bioengineering of vascular grafts holds great potential to address the shortcomings associated with autologous and conventional synthetic vascular grafts used for small diameter grafting procedures. Lumen endothelialization of bioengineered vascular grafts is essential to provide an antithrombogenic graft surface to ensure long-term patency after implantation. Conventional methods used to assess endothelialization in vitro typically involve periodic harvesting of the graft for histological sectioning and staining of the lumen. Endpoint testing methods such as these are effective but do not provide real-time information of endothelial cells in their intact microenvironment, rather only a single time point measurement of endothelium development. Therefore, nondestructive methods are needed to provide dynamic information of graft endothelialization and endothelium maturation in vitro. To address this need, we have developed a nondestructive fiber optic based (FOB imaging method that is capable of dynamic assessment of graft endothelialization without disturbing the graft housed in a bioreactor. In this study we demonstrate the capability of the FOB imaging method to quantify electrospun vascular graft endothelialization, EC detachment, and apoptosis in a nondestructive manner. The electrospun scaffold fiber diameter of the graft lumen was systematically varied and the FOB imaging system was used to noninvasively quantify the affect of topography on graft endothelialization over a 7-day period. Additionally, results demonstrated that the FOB imaging method had a greater imaging penetration depth than that of two-photon microscopy. This imaging method is a powerful tool to optimize vascular grafts and bioreactor conditions in vitro, and can be further adapted to monitor endothelium maturation and response to fluid flow bioreactor preconditioning.

Effect of surface texture of grafted films on antithrombogenicity

International Nuclear Information System (INIS)

Otsuhata, K.; Razzak, M.T.; Castanares, R.L.; Tabata, Y.; Ohashi, F.; Takkeuchi, A.

1985-01-01

The relation between grafting conditions and antithrombogenicity has been examined from the purpose of clearing the necessity of controlling grafting conditions to enhance blood compatibility. The grafting systems employed here were N,N-dimethylacrylamide (DMAA) - poly(tetrafluoroethylene) (PTFE) and DMAA - poly(ethylene-co-tetrafluoroethylene) (AFLON) and grafting parameters were dose rate, monomer concentration and total dose (irradiation time). Grafting DMAA on to the substrates was carried out by using simultaneous irradiation method of gamma rays from a 60 Co source. After evaluation of blood compatibility of the grafted films by using in vitro tests, it has been clear that control of grafting conditions is important. Especially, in both grafting systems, dose rate control has found to be very important for blood compatibility. When higher dose rate of 1.0 x 10 5 to 3.0 x 10 5 rad/hr was used for grafting DMAA on to PTFE or AFLON, blood compatibility of the substrates was not enhanced, whereas it was improved when the grafting was carried out at lower dose rate of 0.97 x 10 4 rad/hr. The correlation between dose rate and antithrombogenicity has been interpreted in terms of surface-roughness of the grafted films. By scanning electron microscope (SEM) - observation, it has been observed that higher dose rate makes the surface rough, whereas lower dose rate makes it smooth. (author)

Magnetizable stent-grafts enable endothelial cell capture

Energy Technology Data Exchange (ETDEWEB)

Tefft, Brandon J. [Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (United States); Uthamaraj, Susheil [Division of Engineering, Mayo Clinic, Rochester, MN (United States); Harburn, J. Jonathan [School of Medicine, Pharmacy and Health, Durham University, Stockton-on-Tees (United Kingdom); Hlinomaz, Ota [Department of Cardioangiology, St. Anne' s University Hospital, Brno (Czech Republic); Lerman, Amir [Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (United States); Dragomir-Daescu, Dan [Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN (United States); Sandhu, Gurpreet S., E-mail: sandhu.gurpreet@mayo.edu [Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (United States)

2017-04-01

Emerging nanotechnologies have enabled the use of magnetic forces to guide the movement of magnetically-labeled cells, drugs, and other therapeutic agents. Endothelial cells labeled with superparamagnetic iron oxide nanoparticles (SPION) have previously been captured on the surface of magnetizable 2205 duplex stainless steel stents in a porcine coronary implantation model. Recently, we have coated these stents with electrospun polyurethane nanofibers to fabricate prototype stent-grafts. Facilitated endothelialization may help improve the healing of arteries treated with stent-grafts, reduce the risk of thrombosis and restenosis, and enable small-caliber applications. When placed in a SPION-labeled endothelial cell suspension in the presence of an external magnetic field, magnetized stent-grafts successfully captured cells to the surface regions adjacent to the stent struts. Implantation within the coronary circulation of pigs (n=13) followed immediately by SPION-labeled autologous endothelial cell delivery resulted in widely patent devices with a thin, uniform neointima and no signs of thrombosis or inflammation at 7 days. Furthermore, the magnetized stent-grafts successfully captured and retained SPION-labeled endothelial cells to select regions adjacent to stent struts and between stent struts, whereas the non-magnetized control stent-grafts did not. Early results with these prototype devices are encouraging and further refinements will be necessary in order to achieve more uniform cell capture and complete endothelialization. Once optimized, this approach may lead to more rapid and complete healing of vascular stent-grafts with a concomitant improvement in long-term device performance. - Highlights: • Magnetic stent-grafts were made from 2205 steel stents and polyurethane nanofibers. • Stent-grafts remained patent and formed a thin and uniform neointima when implanted. • Stent-grafts captured endothelial cells labeled with magnetic nanoparticles. �

Frenuloplasty with a splitthicknes skin graft

International Nuclear Information System (INIS)

Mohammadi, G.; Nnaderpour, M.

2006-01-01

The purpose of this study was to investigate the severity of presenting symptomatology in patients with ankyloglossia and to assess the surgical results of patients undergoing frenuloplasty with split thickness skin graft. During a 4 year period from September 1998 through September 2002, 19 patients of ankyloglosia underwent frenuloplasty with a split thickness skin graft. All skin grafts were taken from arm. There were 11 males and 8 females. The average length of the lingual frenulum was 3.5 mm. Twelve children were over 4 years old and were primarily operated with this technique. In the 7 patients, Z plasty had been performed previously but failed and cicatrisation caused ankyloglosia. There were two minor postoperative complications, one hematoma, and other graft dehiscence with cicatrisation. The mobility of the tongue after one year was excellent. There were no complications in donor site. Frenuloplasty with split thickness skin graft is the best and easy procedure with good results for children over 4 years and those who fail primary closure. (author)

The in vivo blood compatibility of bio-inspired small diameter vascular graft: effect of submicron longitudinally aligned topography

Science.gov (United States)

2013-01-01

Background Cardiovascular disease is the leading cause of deaths worldwide and the arterial reconstructive surgery remains the treatment of choice. Although large diameter vascular grafts have been widely used in clinical practices, there is an urgent need to develop a small diameter vascular graft with enhanced blood compatibility. Herein, we fabricated a small diameter vascular graft with submicron longitudinally aligned topography, which mimicked the tunica intima of the native arterial vessels and were tested in Sprague–Dawley (SD) rats. Methods Vascular grafts with aligned and smooth topography were prepared by electrospinning and were connected to the abdominal aorta of the SD rats to evaluate their blood compatibility. Graft patency and platelet adhesion were evaluated by color Doppler ultrasound and immunofluorescence respectively. Results We observed a significant higher patency rate (p = 0.021) and less thrombus formation in vascular graft with aligned topography than vascular graft with smooth topography. However, no significant difference between the adhesion rates on both vascular grafts (smooth/aligned: 0.35‰/0.12‰, p > 0.05) was observed. Moreover, both vascular grafts had few adherent activated platelets on the luminal surface. Conclusion Bionic vascular graft showed enhanced blood compatibility due to the effect of surface topography. Therefore, it has considerable potential for using in clinical application. PMID:24083888

Antibacterial Modification of Microcrystalline Cellulose by Grafting Copolymerization

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Ying Liu

2015-11-01

Full Text Available Microcrystalline cellulose (MCC has the advantage of a high specific surface area as compared to that of conventional cellulose fibers. In this study the monomer methacrylamide (MAM was used to treat MCC by grafting copolymerization. SEM, FTIR, and solid 13C NMR were used to characterize the morphology and composition of MAM-g-MCC. After the chlorination of MAM-g-MCC with 10% sodium hypochlorite solution, the grafted MCC exhibited antibacterial activity as a result of the formation of N-Cl bonds. The thermal stability, antibacterial ability, and storage stability of chlorinated MAM-g-MCC were also studied. The results showed that the chlorinated MAM-g-MCC had excellent storage stability and could inactivate all S. aureus and E. coli O157:H7 within 10 min.

Local graft irradiation in renal transplant rejection

International Nuclear Information System (INIS)

Kawamura, Masashi; Kataoka, Masaaki; Itoh, Hisao

1990-01-01

From 1977 to 1988, of 142 renal transplantations, seven recipients (4.9%) received local graft irradiation following rejective reaction refractory to antirejection medical managements. Concurrent with the administration of pulsed high dose methylprednisolone and other antirejection medical managements, the graft was irradiated with a total dose of 6.0 Gy-150 cGy per fraction every other day at the midplane of the graft using two opposing portals of 4MX Linac. The fields were defined by palpation and echography. All patients had improvements in serum creatinine on the 10th day after beginning the irradiation. Four patients with peripheral lymphocytosis during the irradiation combined with pulsed high dose methylprednisolone improved in renal functions. On the other hand, out of 3 patients with lymphcytopenic changes, in two the transplanted graft was removed due to deteriorations, and the other patient is currently suffering from chronic rejection. Local graft irradiation can be useful in maintaining a rejective graft and reversing its functions in some patients whose rejective reaction failed to respond to the antirejection medical managements. (author)

Cartilage grafting in nasal reconstruction.

Science.gov (United States)

Immerman, Sara; White, W Matthew; Constantinides, Minas

2011-02-01

Nasal reconstruction after resection for cutaneous malignancies poses a unique challenge to facial plastic surgeons. The nose, a unique 3-D structure, not only must remain functional but also be aesthetically pleasing to patients. A complete understanding of all the layers of the nose and knowledge of available cartilage grafting material is necessary. Autogenous material, namely septal, auricular, and costal cartilage, is the most favored material in a free cartilage graft or a composite cartilage graft. All types of material have advantages and disadvantages that should guide the most appropriate selection to maximize the functional and cosmetic outcomes for patients. Copyright © 2011 Elsevier Inc. All rights reserved.

Graft copolimerization of hydrophilic monomers onto irradiated polypropylene fibers

International Nuclear Information System (INIS)

Sundardi, F.

1978-01-01

A method of graft copolymerization of hydrophilic monomers, such as 1-vinyl-2-pyrrolidone, acrylonitrile, acrylic acid, and acrylamide, onto irradiated polypropylene fibers has been studied. γ ray as well as electron beam were employed for the irradiation processes. Graft-copolymerization kinetics and the properties of grafted fibers have been investigated. Moisture regain, dyes absorption, and melting point of the grafted fibers were found to increase with the increasing of the degree of grafting. Polypropylene for 1-vinyl-2-pyrrolidone grafted fibers showed excellent dye absorption for almost all kinds of dyes such as direct, basic, acid, reactive, disper, and naphthol dyes. However, for polypropylene acrylic acid grafted fibers, the colorfastness to washing was found to be unsatisfactory. The colorfastness to washing for polypropylene 1-vinyl-2-pyrrolidone grafted fibers was found to be fairly good for certain types of dyes such as vat and naphthol dyes. (author)

Development of sodium alginate and konkoli gum- grafted ...

African Journals Online (AJOL)

STORAGESEVER

2008-05-02

May 2, 2008 ... grafted-polyacrylamide blend membrane: optimization of grafting conditions .... medium and reduce rate of termination by the coupling of the growing ... Effect of time. The time conversion curve of the graft copolymerization ...

In-111 oxine autologous labeled platelets in the diagnosis of kidney graft rejection

International Nuclear Information System (INIS)

Martin-Comin, J.; Roca, M.; Grino, J.M.; Paradell, C.; Caralps, C.

1983-01-01

The usefulness of In-111 oxine labeled autologous platelets in the diagnosis of renal graft rejection was studied. The method is based on imaging of the graft area at 4, 24, 48, and 72 hours after the injection of the labeled cells. The study was done in 31 renal transplant recipients. The control group included four patients with normal renal function without evidence of rejection. No platelet uptake was observed in any of them. The study group included 22 patients with acute rejection which was confirmed histologically in 13. One case of chronic vascular type rejection of the graft tracer uptake was seen. There was a false-positive result due to a perirenal hematoma. In three patients with a non-immunological sudden impairment of renal function, no activity was detected in the graft area. We also evaluated the changes in platelet trapping throughout the study and they seemed to correlate with the response to the antirejection therapy

Synthesis of ion exchange membrane by radiation grafting of acrylic acid onto polyethylene

International Nuclear Information System (INIS)

Ishigaki, I.; Sugo, T.; Senoo, K.; Takayama, T.; Machi, S.; Okamoto, J.; Okada, T.

1981-01-01

Radiation grafting of vinyl monomers onto polymer films has been extensively studied by many workers. In the preirradiation method of grafting a polymer substrate is activated by irradiation (either in the presence or absence of oxygen) and subsequently allowed to react with a monomer. The preirradiation method was utilized in this study to synthesize an ion exchange membrane useful for a battery separator by grafting acrylic acid onto polyethylene film. The battery separator should be chemically and thermally stable, sufficiently durable in electrolyte as well as highly electrically conductive. Membranes made from regenerated cellulose, e.g., cellophane, have long been used as a separator in the batteries with alkaline electrolyte, such as silver oxide primary cell. However, it has poor durability, as short as one year, due to breakdown of the membrane during operation or storing. The acrylic acid-grafted polyethylene film was found to be quite useful for a separator in the alkaline batteries. This membrane has a high electric conductivity and an excellent durability. (author)

Antecedent thermal injury worsens split-thickness skin graft quality: A clinically relevant porcine model of full-thickness burn, excision and grafting.

Science.gov (United States)

Carlsson, Anders H; Rose, Lloyd F; Fletcher, John L; Wu, Jesse C; Leung, Kai P; Chan, Rodney K

2017-02-01

Current standard of care for full-thickness burn is excision followed by autologous split-thickness skin graft placement. Skin grafts are also frequently used to cover surgical wounds not amenable to linear closure. While all grafts have potential to contract, clinical observation suggests that antecedent thermal injury worsens contraction and impairs functional and aesthetic outcomes. This study evaluates the impact of antecedent full-thickness burn on split-thickness skin graft scar outcomes and the potential mediating factors. Full-thickness contact burns (100°C, 30s) were created on the backs of anesthetized female Yorkshire Pigs. After seven days, burn eschar was tangentially excised and covered with 12/1000th inch (300μm) split-thickness skin graft. For comparison, unburned wounds were created by sharp excision to fat before graft application. From 7 to 120days post-grafting, planimetric measurements, digital imaging and biopsies for histology, immunohistochemistry and gene expression were obtained. At 120days post-grafting, the Observer Scar Assessment Scale, colorimetry, contour analysis and optical graft height assessments were performed. Twenty-nine porcine wounds were analyzed. All measured metrics of clinical skin quality were significantly worse (pskin graft quality, likely by multiple mechanisms including burn-related inflammation, microscopically inadequate excision, and dysregulation of tissue remodeling. A valid, reliable, clinically relevant model of full-thickness burn, excision and skin replacement therapy has been demonstrated. Future research to enhance quality of skin replacement therapies should be directed toward modulation of inflammation and assessments for complete excision. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

Kinetics of vein graft hyperplasia

International Nuclear Information System (INIS)

Zwolak, R.M.; Adams, M.C.; Clowes, A.W.

1986-01-01

Human aortocoronary vein grafts fail due to accelerated occlusive disease. The possibility that this is related to cellular hyperplasia was investigated in a rabbit model where kinetics of vein graft thickening, endothelial (EC) repair, and smooth muscle cell (SMC) proliferation were measured from 2 days to 24 weeks after implanting jugular vein segments in the carotid artery. Immediately after graft placement focal EC denudation was observed. These defects were repaired within 1 week and did not recur. By 4 weeks intimal area had increased 30 fold from 0.028 +/- 0.004 to 0.705 +/- 0.021 mm 2 , and a 24 weeks was 0.93 +/- 0.21 mm 2 . This response did not produce a reduction in graft lumen area. EC and SMC thymidine-labeling index were measured by en face and cross-section autoradiography after injection of 3 H-thymidine and perfusion fixation. Despite rapid EC surface repair EC labeling index remained elevated and only returned to normal levels at 12 weeks; SMC labeling was 10 fold greater than baseline even at 24 weeks (0.22% vs 0.02%). SMC mass demonstrated morphometrically increased between 2 and 12 weeks. Intimal thickening in vein grafts is due to SMC proliferation and develops after the EC layer has been restored. In contrast, intimal SMC proliferate in damaged arteries when the EC layer is absent and cease when the EC layer is regenerated

Sodium and chloride exclusion and retention by non-grafted and grafted melon and Cucurbita plants

Science.gov (United States)

Edelstein, M.; Plaut, Z.; Ben-Hur, M.

2011-01-01

The effects of grafting on Na and Cl– uptake and distribution in plant tissues were quantified in a greenhouse experiment using six combinations of melon (Cucumis melo L. cv. Arava) and pumpkin (Cucurbita maxima Duchesne×Cucurbita moschata Duchesne cv. TZ-148): non-grafted, self-grafted, melons grafted on pumpkins, and pumpkins grafted on melons. Total Na concentration in shoots of plants with pumpkin or melon rootstocks was 400 mmol kg−1, respectively, regardless of the scion. In contrast, shoot Cl– concentrations were quite similar among the different scion–rootstock combinations. Na concentrations in exudates from cut stems of plants with a pumpkin rootstock were very low (<0.18 mM), whereas those in the exudates of plants with melon rootstocks ranged from 4.7 mM to 6.2 mM, and were quite similar to the Na concentration in the irrigation water. Root Na concentrations averaged 11.7 times those in the shoots of plants with pumpkin rootstocks, while in plants with melon rootstocks, values were similar. Two mechanisms could explain the decrease in shoot Na concentrations in plants with pumpkin rootstocks: (i) Na exclusion by the pumpkin roots; and (ii) Na retention and accumulation within the pumpkin rootstock. Quantitative analysis indicated that the pumpkin roots excluded ∼74% of available Na, while there was nearly no Na exclusion by melon roots. Na retention by the pumpkin rootstocks decreased its amount in the shoot by an average 46.9% compared with uniform Na distribution throughout the plant. In contrast, no retention of Na could be found in plants grafted on melons. PMID:20729482

Sodium and chloride exclusion and retention by non-grafted and grafted melon and Cucurbita plants.

Science.gov (United States)

Edelstein, M; Plaut, Z; Ben-Hur, M

2011-01-01

The effects of grafting on Na and Cl(-) uptake and distribution in plant tissues were quantified in a greenhouse experiment using six combinations of melon (Cucumis melo L. cv. Arava) and pumpkin (Cucurbita maxima Duchesne×Cucurbita moschata Duchesne cv. TZ-148): non-grafted, self-grafted, melons grafted on pumpkins, and pumpkins grafted on melons. Total Na concentration in shoots of plants with pumpkin or melon rootstocks was 400 mmol kg(-1), respectively, regardless of the scion. In contrast, shoot Cl(-) concentrations were quite similar among the different scion-rootstock combinations. Na concentrations in exudates from cut stems of plants with a pumpkin rootstock were very low (<0.18 mM), whereas those in the exudates of plants with melon rootstocks ranged from 4.7 mM to 6.2 mM, and were quite similar to the Na concentration in the irrigation water. Root Na concentrations averaged 11.7 times those in the shoots of plants with pumpkin rootstocks, while in plants with melon rootstocks, values were similar. Two mechanisms could explain the decrease in shoot Na concentrations in plants with pumpkin rootstocks: (i) Na exclusion by the pumpkin roots; and (ii) Na retention and accumulation within the pumpkin rootstock. Quantitative analysis indicated that the pumpkin roots excluded ∼74% of available Na, while there was nearly no Na exclusion by melon roots. Na retention by the pumpkin rootstocks decreased its amount in the shoot by an average 46.9% compared with uniform Na distribution throughout the plant. In contrast, no retention of Na could be found in plants grafted on melons.

Bone Graft Substitutes : Developed for Trauma and Orthopaedic Surgery

NARCIS (Netherlands)

J. van der Stok (Johan)

2015-01-01

markdownabstract__Abstract__ Bone grafting was established in the 19th century and has become a common procedure in which bone defects are filled with bone grafts or bone graft substitutes. Bone defects that require bone grafting are encountered in approximately 10% of trauma and orthopaedic

Bio-active nanocomposite films based on nanocrystalline cellulose reinforced styrylquinoxalin-grafted-chitosan: Antibacterial and mechanical properties.

Science.gov (United States)

Fardioui, Meriem; Meftah Kadmiri, Issam; Qaiss, Abou El Kacem; Bouhfid, Rachid

2018-07-15

In this study, active nanocomposite films based on cellulose nanocrystalline (NCC) reinforced styrylquinoxalin-grafted-chitosan are prepared by solvent-casting process. The structures of the two styrylquinoxaline derivatives were confirmed by FT-IR, 1 H, 13 C NMR spectral data and the study of the antibacterial activity against Escherichia coli (EC), Staphylococcus aureus (SA), Bacillus subtilis (BS) and Pseudomonas Aeruginosa (PA) exhibits that they have a good antibacterial activity against (PA). On their side, the styrylquinoxalin-g-chitosan films are able to inhibit the growth of (PA) through their contact area without being damaged by the antibacterial test conditions. The addition of 5wt% of NCCs as nano-reinforcements revealed no change at the level of antibacterial activity but led to an important improvement of the mechanical properties (more than 60% and 90% improvement in Young's modulus and tensile strength, respectively) of the modified-chitosan films. Thereby, the present nanocomposite films are prepared by a simple way and featured by good mechanical and antibacterial properties which enhance the possibility to use them as bio-based products for biomedical and food packaging. Copyright © 2018 Elsevier B.V. All rights reserved.

Influenţa stadiului de pornire în vegetaţie a portaltoiului şi a nivelului de altoire asupra procentului de prindere în cazul altoirii la molidul argintiu[Influence of the parent stock phenology and grafting level on successfull grafting of silver Colorado spruce

Directory of Open Access Journals (Sweden)

George Mazăre

2014-08-01

Full Text Available Having no importance for Romanian forestry, Picea pungens Engelm. is an ornamental species, often seen in Romanian parks and gardens. There are cultivated especially glauca and argentea forms. The biggest problem of this forms is getting seedlings. The generative way is not recommended because, although at begin those specimens obtained have the characteristic color of the variety, with the passage of time the color disappears. So, the vegetative way remains the only possible way in order to obtain best specimens. Propagation method used in these experiments is side-veener- grafting. The rootstock was represented by Picea abies, which was grafted with scion collected from Picea pungens argentea variety. The experiment factors were vegetative stage of rootstock and grafting level. Regarding the first factor, we chose two graduations, the grafting being made on less active rootstock and well active rootstock. Regarding the grafting level, the graft was made to the first growth, on the second and on the third growth. The behavior of grafted seedlings was followed throughout the growing season, with the work of care applied in the process, but the final inventory of surviving grafts was made at the end of the growing season. To interpret the results on grafting efficiency, expressed by number of slips caught, the data obtained from the measurements were statistically processed by variance analysis method, using the method of multiple comparisons (the Duncan test.

Improvement of the polymer stability by radiation grafting

International Nuclear Information System (INIS)

Ranogajec, F.; Mlinac-Misak, M.

2004-01-01

Losses of the stabilizer due to extractability or volatility immediately affect the ultimate performance of polymer products. A new approach to increase the persistence of the stabilizer in the final product is to chemically bind it to the polymer backbone. Radiation grafting or crosslinking could be an efficient method for this, when the stabilizer is polymerizable. By a mutual gamma irradiation method photoprotector 2-hydroxy-4-(3-methacryloxy-2-hydroxy-propoxy) benzophenone has been readily grafted to low-density polyethylene in benzene, tetrahydrofuran and methanol solution, respectively. Surface grafting occurs in a methanol solution of stabilizer, while in benzene and tetrahydrofuran solutions of the stabilizer, grafting proceeds more or less in the inner parts of the polymeric film as well. UV stability tests and changes in the mechanical properties of artificially and naturally aged films indicate pronounced protective effect achieved by the grafted stabilizer. Surface grafting is an efficient photostabilization method since the grafted stabilizer is chemically bound to a polymeric surface and in this way the problem of evaporation of blended stabilizers during the prolonged use of polymeric materials is eliminated

Radiation-induced grafting of styrene on polypropylene pellets

International Nuclear Information System (INIS)

Souza, Camila P.; Ferreira, Henrique P.; Parra, Duclerc F.; Lugao, Ademar B.

2009-01-01

The changes of radiation-induced in polypropylene (PP) pellets exposed to gamma irradiation in inert atmosphere were investigated in correlation with the applied doses (10 and 50 kGy). Also, results from the grafting of styrene onto PP pellets using simultaneous irradiation at the same doses are presented. The grafting reaction was carried out using toluene as solvent, under nitrogen atmosphere and at room temperature. The properties of the irradiated and grafted PP pellets were studied using Melt Flow Index, thermal analysis (TG and DSC), and ATR-IR. The degree of grafting (DOG) for the grafted pellets was gravimetrically determined. The results showed that radiation-induced graft polymerization on pellets were successfully obtained and the influence of dose irradiated did not change the thermal properties in spite of the increase in the MFI and consequently this increase in the viscosity results an decrease the molecular mass. The MFI for grafted pellets was not achievable because the high degree of viscosity of polymer, even arising the test temperature, the polymer was not flow enough. (author)

Bone graft viability evaluated by three phase bone scan

International Nuclear Information System (INIS)

Ljiljana Jaukovic Rajko Spaic; Marijan Novakovic; Srbislav Stosic

2004-01-01

Bone defects resulting war injury can be replaced by microvascular bone grafts from fibula. Aim: The aim of this study was to assess the value of three phase (3P) bone scintigraphy in the early detection of the bone graft complications. Method: 3P bone scans were performed in four patients (two after mandible reconstruction with micro vascular fibular bone grafts, one after fibular transplantation for ulnar and one with humeral reconstruction). First dynamic phase scan was performed immediately after iv injection of 740 MBq Tc- 99m DPD, acquiring 15 two seconds duration frames. Second, early static scan was performed during next 300 seconds, and third, delayed scan three hours later. All scans were obtained under the bone graft region. The scans were evaluated using ROI under graft region and the corresponding contra lateral area. Blood flow in graft region was determined using first phase scan, and tracer uptake in the same region was determined using second and third phase scans. Results: in all patients blood flow in graft region was particularly normal. Tracer uptake in one of two patients with mandible reconstruction was diffusely increased in graft, strongly suggesting infection; In the other patient delayed scan showed no tracer uptake in graft center .Both patients with ulnar and humeral reconstruction showed only slightly decreased tracer uptake in bone grafts. 3 phase bone scintigraphy may play a role in the evaluation of bone graft viability by predicting the infection and necrosis. (authors)

Migration of human antigen-presenting cells in a human skin graft onto nude mice model after contact sensitization

NARCIS (Netherlands)

Hoefakker, S.; Balk, H.P.; Boersma, W.J.A.; Joost, T. van; Notten, W.R.F.; Claassen, E.

1995-01-01

Fluorescent contact chemical allergens provoke sensitization after application on both syngeneic and allogeneic skin grafts in mice. We attempted to determine whether the functional activity in a contact sensitization response of human skin graft was affected at the level of antigen uptake and

Albumin grafting on polymer surfaces by gamma-irradiation

International Nuclear Information System (INIS)

Kamath, K.R.; Park, K.; DeMeo, D.

1993-01-01

Polymeric biomaterial surfaces were modified by albumin grafting to improve their blood compatibility. Albumin molecules were functionalized by introduction of double bonds. The functionalized albumin was covalently attached to polypropylene fibers, polycarbonate, and poly(vinyl chloride) by gamma-irradiation. ESCA and ATR/FTIR analysis of the control and grafted surfaces was conducted. Albumin grafting efficiency was found to be dependent on the gamma-irradiation time and the concentration of albumin as indicated by platelet adhesion studies. The grafted albumin molecules were not displaced when exposed to blood for prolonged time period. Finally, PLEXUS oxygenators grafted with albumin using this approach showed a significant reduction in platelet adhesion when compared to control

ESR spectroscopic investigations of the radiation-grafting of fluoropolymers

Energy Technology Data Exchange (ETDEWEB)

Huebner, G; Roduner, E [University of Stuttgart (Germany); Brack, H P; Scherer, G G [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1999-08-01

ESR spectroscopic investigations have clarified the influence of several preparative parameters on the reaction rates and yields obtained in the radiation-grafting method used at PSI to prepare proton-conducting polymer membranes. At a given irradiation dose, a higher concentration of reactive radical sites was detected in ETFE films than in FEP films. This higher concentration explains the higher grafting levels and rates of the ETFE films found in our previous grafting experiments. Taken together, the in-situ ESR experiments and grafting experiments show that the rates of disappearance of radical species and grafting rates and final grafting levels depend strongly on the reaction temperature and the oxygen content of the system. Average grafted chain lengths were calculated to contain about 1,000 monomer units. (author) 2 figs., 4 refs.

Vascularised Fibular Graft for a Radial Defect following Tumour ...

African Journals Online (AJOL)

HP

The mass was located on the radial aspect of the distal right ... modification, internal or external fixation with bone grafting, structural grafts of ... Our index case report demonstrates that free vascularized fibular graft transfer is a feasible option ... structural support, the potential for graft hypertrophy, relative resistance to ...

The study on grafting comonomer of n-butyl acrylate and styrene onto poly(ethylene terephthalate) film by gamma-ray induced graft copolymerization

Energy Technology Data Exchange (ETDEWEB)

Ping Xiang; Wang Mozhen [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Ge Xuewu, E-mail: xwge@ustc.edu.c [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2010-09-15

Poly(ethylene terephthalate) (PET) film was successfully grafted with n-butyl acrylate and styrene comonomer through gamma-ray induced graft copolymerization. The degree of grafting (DG) and the composition of grafted side chain were characterized by {sup 1}H NMR. It was found that St can inhibit the homopolymerization of BA effectively and increase the DG when the concentration of comonomer mixture is kept constant. The proportion of St to BA in grafted side chain has a positive dependence on the feed ratio of St, which ultimately approaches the feed ratio. The thermal properties of poly(ethylene terephthalate)-graft-poly(n-butyl acrylate-co-styrene) (PET-g-P(BA-co-St)) films were investigated by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). The T{sub g} of PET decreases with the DG, indicating that the grafted P(BA-co-St) copolymer has good compatibility with PET backbone.

Biofabrication and testing of a fully cellular nerve graft

International Nuclear Information System (INIS)

Owens, Christopher M; Marga, Francoise; Forgacs, Gabor; Heesch, Cheryl M

2013-01-01

Rupture of a nerve is a debilitating injury with devastating consequences for the individual's quality of life. The gold standard of repair is the use of an autologous graft to bridge the severed nerve ends. Such repair however involves risks due to secondary surgery at the donor site and may result in morbidity and infection. Thus the clinical approach to repair often involves non-cellular solutions, grafts composed of synthetic or natural materials. Here we report on a novel approach to biofabricate fully biological grafts composed exclusively of cells and cell secreted material. To reproducibly and reliably build such grafts of composite geometry we use bioprinting. We test our grafts in a rat sciatic nerve injury model for both motor and sensory function. In particular we compare the regenerative capacity of the biofabricated grafts with that of autologous grafts and grafts made of hollow collagen tubes by measuring the compound action potential (for motor function) and the change in mean arterial blood pressure as consequence of electrically eliciting the somatic pressor reflex. Our results provide evidence that bioprinting is a promising approach to nerve graft fabrication and as a consequence to nerve regeneration. (paper)

Indium-111 platelet imaging for detection of platelet deposition in abdominal aneurysms and prosthetic arterial grafts

International Nuclear Information System (INIS)

Ritchie, J.L.; Stratton, J.R.; Thiele, B.; Haminton, G.W.; Warrick, L.N.; Huang, T.W.; Harker, L.A.

1981-01-01

Thirty-four platelet imaging studies were performed in 23 patients to determine whether platelet deposition could be detected in patients with vascular aneurysms (18 patients) or in patients in whom Dacron prosthetic grafts had been placed (5 patients). In patients in whom abnormal platelet deposition was detected, the effect of administration of platelet-active drugs on platelet deposition was examined. Of the 18 patients with an aneurysm, 12 had equivocally positive studies on initial imaging and 2 had equivocally positive images. Of five patients with Dacron arterial grafts in place, four had diffuse platelet deposition in the grafts; the fifth patient had a platelet deposition only in a pseudoaneurysm. Eight patients with an abdominal aneurysm and positive or equivocally positive baseline images were restudied during platelet-active drug therapy either with aspirin plus dipyridamole (seven patients) or with sulfinpyrazone (four patients). No patient studied during treatment with aspirin plus dipyridamole had detectably decreased platelet deposition compared with baseline determinations. In contrast, two of four patients studied while receiving sulfinpyrazone showed decreased platelet deposition. Thus, platelet imaging may be of value for studying platelet physiology in vivo and for assessing platelet-active drugs and the thrombogenicity of prosthetic graft materials in human beings

Quantitative evaluation of endothelial cell attachment to vascular graft materials using In-111 Oxine label

Energy Technology Data Exchange (ETDEWEB)

Park, H.M.; Kesler, K.A.; Stinson, J.; Mock, B.; Arnold, M.

1985-05-01

Human umbilical vein endothelial cells were harvested, cultured and labeled with In-111 oxine using a modification of the technique described by Sharefkin et al. Average cell labeling efficiency was 42%. Two graft materials, polytetrafluoroethylene (Gortex) and polyester elastomer (Hytrel), with and without pretreatment with human fibronectin (FN) were incubated with the labeled cells. Quantitation of In-111 activity was done 3 times: at inoculation, after incubation (attachment) and after 1 hr of in vitro perfusion (retention). The average attachment ranged from 53% to 99.5%. The In-111 activity attached ranged from 10 to 20 ..mu..Ci per graft. A gamma camera with medium energy collimator and two pulse height analyzers for 173 and 247 keV photons with 20% window and an on-line computer was used. Images were obtained in 1.5 zoom mode. The count rate response to a In-111 point source up to 150 ..mu..Ci was linear. The results indicate Hytrel permits better endothelial cell attachment than Gortex and FN coating enhances the strength of attachment to both graft materials. The authors conclude that In-111 Oxine labeling is a reliable method for quantitatively evaluating endothelial cell attachment to vascular graft materials.

Photoacoustic detection of neovascularities in skin graft

Science.gov (United States)

Yamazaki, Mutsuo; Sato, Shunichi; Saitoh, Daizo; Ishihara, Miya; Okada, Yoshiaki; Ashida, Hiroshi; Obara, Minoru

2005-04-01

We previously proposed a new method for monitoring adhesion of skin graft by measuring photoacoustic (PA) signal originated from the neovascularities. In this study, immunohistochemical staining (IHC) with CD31 antibody was performed for grafted skin tissue to observe neovascularity, and the results were compared with PA signals. We also used a laser Doppler imaging (LDI) to observe blood flow in the grafted skin, and sensitivity of PA measurement and that of LDI were compared. In rat autograft models, PA signals were measured for the grafted skin at postgrafting times of 0-48 h. At 6 h postgrafting, PA signal was observed in the skin depth region of 500-600 mm, while the results of IHC showed that angiogenesis occurred at the depth of about 600 mm. Depths at which PA signal and angiogenesis were observed decreased with postgrafting time. These indicate that the PA signal observed at 6 h postgrafting originated from the neovascularities in the skin graft. Results of LDI showed no blood-originated signal before 48 h postgrafting. These findings suggest that PA measurement is effective in monitoring the adhesion of skin graft in early stage after transplantation.

Quantifying Long-term Retention of Excised Fat Grafts

DEFF Research Database (Denmark)

Herly, Mikkel; Ørholt, Mathias; Glovinski, Peter V.

2017-01-01

Background: Predicting the degree of fat graft retention is essential whenplanning reconstruction or augmentation with free fat grafting. Most surgeonsobserve volume loss over time after fat grafting; however, the portion lost toresorption after surgery is still poorly defined, and the time to re...

Radiation grafting of dimethylaminopropylacrylamide and dimethylaminopropylmethacrylamide onto polyethylene

Energy Technology Data Exchange (ETDEWEB)

Burillo, Guillermina; Oseguera, M.A. [UNAM, Inst. de Ciencias Nucleares, Mexico City (Mexico); Vazquez, Carmen; Castillo, L.P. del [UNAM, Inst. de Investigaciones en Materiales, Mexico City (Mexico)

1997-11-01

Radiation-induced grafting of dimethylaminopropylacrylamide and dimethylamino-propylmethacrylamide onto polyethylene films, by direct grafting of the vinyl monomers to a polymer by mutual irradiation, has been investigated. The kinetics of the reaction were studied at different irradiation temperatures, monomer concentration and dose rates of gamma rays, and the appropriate reaction conditions for graft polymerization were determined. The thermal and mechanical behavior of the grafted films by means of DMA, TMA, DSC and TGA were also investigated. (author).

Oral mucosa grafts for urethral reconstruction

African Journals Online (AJOL)

reports reveal that split and full thickness skin grafts from the scrotum, penis, extragenital sites (ureter, saphenous .... Table 1: Summary of the history of oral mucosa grafts for urethroplasty .... advised that care should be taken when suturing the.

Long-term results of PTFE grafts.

Science.gov (United States)

Hedin, Ulf

2015-01-01

Vascular surgeons are essential in "lifeline" creation for hemodialysis patients and should be the central player in any multidisciplinary access service together with nephrologists, dialysis staff and interventional radiology. In this position, access surgeons are involved in complicated clinical decision making regarding primary and secondary access selection, which throughout the last decade has been largely aided, and influenced, by national and international guidelines as well as other initiatives. These recommendations, unanimously and appropriately, advocate the placement of native fistulas over synthetic grafts (the majority grafts from expanded polytetrafluoroethylene, ePTFE, herein referred to as PTFE) based on the superiority of fistulas with respect to complications such as infections and thrombosis. Nevertheless, the use of PTFE grafts for hemodialysis access is an accepted and firmly established alternative to native fistulas where data today reveal unwanted consequences to overinterpretation of established guidelines such as increased catheter use. This information highlights a need for an adjustment of access selection strategies based on patient-centered algorithms. Here, available results on PTFE graft performance in hemodialysis access is recapitulated, with respect to both conventional grafts and technical modifications, and conclude with a modified approach to primary access selection.

The autologus graft of epithelial tissue culture

Directory of Open Access Journals (Sweden)

Minaee B

1999-08-01

Full Text Available With the intention of research about culture and autologus graft of epithelial tissue we used 4 french Albino Rabbits with an average age of 2 months. After reproduction on the support in EMEM (Eagle's Minimum Essential Medium we used this for graft after 4 weeks. This region which grafted total replaced. After fixation of this sample and passing them through various process, histological sections were prepared. These sections were stained with H & E and masson's trichrome and studied by light microscope. We succeeded in graft. We hope in the near future by using the method of epithelium tissue culture improving to treat burned patients.

Results of triple muscle (sartorius, tensor fascia latae and part of gluteus medius pedicle bone grafting in neglected femoral neck fracture in physiologically active patients

Directory of Open Access Journals (Sweden)

Pankaj Kumar Mishra

2014-01-01

Full Text Available Background: Femoral neck fractures are notorious for complications like avascular necrosis and nonunion. In developing countries, various factors such as illiteracy, low socioeconomic status, ignorance are responsible for the delay in surgery. Neglected fracture neck femur always poses a formidable challenge. The purpose of this study was to evaluate the results of triple muscle pedicle bone grafting using sartorius, tensor fasciae latae and part of gluteus medius in neglected femoral neck fracture. Materials and Methods: This is a retrospective study with medical record of 50 patients, who were operated by open reduction, internal fixation along with muscle pedicle bone grafting by the anterior approach. After open reduction, two to three cancellous screws (6.5 mm were used for internal fixation in all cases. A bony chunk of the whole anterior superior iliac spine of 1 cm thickness, 1 cm width and 4.5 cm length, taken from the iliac crest comprised of muscle pedicle of sartorius, tensor fascia latae and part of gluteus medius. Then the graft with all three muscles mobilized and put in the trough made over the anterior or anterosuperior aspect of the femoral head. The graft was fixed with one or two 4.5 mm self-tapping cortical screw in anterior to posterior direction. Results: 14 patients were lost to followup. The results were based on 36 patients. We observed that in our series, there was union in 34, out of 36 (94.4% patients. All patients were within the age group of 15-51 years (average 38 years with displaced neglected femoral neck fracture of ≥30 days. Mean time taken for full clinicoradiological union was 14 weeks (range-10-24 weeks. Conclusion: Triple muscle pedicle bone grafting gives satisfactory results for neglected femoral neck fracture in physiologically active patients.

Acrylique acid grafted polyolefines. Thermoadhesive applications

International Nuclear Information System (INIS)

Guimon, Claude

1979-01-01

Radiochemical grafting of polyolefines by peroxidation has been industrialized in France for about 10 years by irradiation of these polymers with an electron accelerator and then treated by acrylic acid. Products obtained show a high adhesivity on metallic surfaces above their melting point. The main application of acrylic acid grafted high density polyethylene is composite film with aluminum foil for thermosealing of plastic bottle caps of sterilized milk. Acrylic acid grafted polypropylene is used in suspension in a volatile liquid for aluminum foil coating satisfying food packaging regulations [fr

Study on radiation grafting of acrylic acid onto fluorine-containing polymers. II. Properties of membrane obtained by preirradiation grafting onto poly(tetrafluoroethylene)

International Nuclear Information System (INIS)

Hegazy, E.S.A.; Ishigaki, I.; Rabie, A.; Dessouki, A.M.; Okamoto, J.

1981-01-01

Some properties of the membranes obtained by the preirradiation grafting of acrylic acid onto poly(tetrafluoroethylene) (PTFE) film have been studied. The dimensional change by grafting and swelling, water uptake, electric conductivity, and mechanical properties of the grafted PTFE films were measured and were found to increase as the grafting proceeds. These properties were found to be dependent mainly on the degree of grafting regardless of grafting conditions except higher monomer concentration (80 wt %). The electric conductivity and mechanical properties of the membranes at 80 wt % monomer concentration is lower than those at a lower monomer concentration. The results suggest that the membranes obtained at 80-wt % acrylic acid solution have a somewhat heterogeneous distribution of electrolyte groups as compared with those prepared at a monomer concentration less than 60 wt %. X-ray microscopy of the grafted films revealed that the grafting begins at the part close to the film surface and proceeds into the center with progressive diffusion of monomer to give finally the homogeneous distribution of electrolyte groups. The membranes show good electrochemical and mechanical properties which make them acceptable for the practical uses as cation exchange membrane

Comparative profiling of miRNAs and target gene identification in distant-grafting between tomato and Lycium (goji berry

Directory of Open Access Journals (Sweden)

A B M Khaldun

2016-10-01

Full Text Available Local translocation of small RNAs between cells is proved. Long distance translocation between rootstock and scion is also well documented in the homo-grafting system, but the process in distant-grafting is widely unexplored where rootstock and scion belonging to different genera. Micro RNAs are a class of small, endogenous, noncoding, gene silencing RNAs that regulate target genes of a wide range of important biological pathways in plants. In this study, tomato was grafted onto goji (Lycium chinense Mill. to reveal the insight of miRNAs regulation and expression patterns within a distant-grafting system. Goji is an important traditional Chinese medicinal plant with enriched phytochemicals. Illumina sequencing technology has identified 68 evolutionary known miRNAs of 37 miRNA families. Moreover, 168 putative novel miRNAs were also identified. Compared with control tomato, 43 (11 known and 32 novels and 163 (33 known and 130 novels miRNAs were expressed significantly different in shoot and fruit of grafted tomato, respectively. The fruiting stage was identified as the most responsive in the distant-grafting approach and 123 miRNAs were found as up-regulating in the grafted fruit which is remarkably higher compare to the grafted shoot tip (28. Potential targets of differentially expressed miRNAs were found to be involved in diverse metabolic and regulatory pathways. ADP binding activities, molybdopterin synthase complex and RNA helicase activity were found as enriched terms in GO (Gene Ontology analysis. Additionally, ‘metabolic pathways’ was revealed as the most significant pathway in KEGG (Kyoto Encyclopedia of Genes and Genomes analysis. The information of the small RNA transcriptomes that are obtained from this study might be the first miRNAs elucidation for a distant-grafting system, particularly between goji and tomato. The results from this study will provide the insights into the molecular aspects of miRNA-mediated regulation in the

Effectiveness of Fibrin Glue in Adherence of Skin Graft.

Science.gov (United States)

Reddy, Konda Sireesha; Chittoria, Ravi Kumar; Babu, Preethitha; Marimuthu, Senthil Kumaran; Kumar, Sudhanva Hemanth; Subbarayan, Elan Kumar; Chavan, Vinayak; Mohapatra, Devi Prasad; Sivakumar, Dinesh Kumar; Friji, M T

2017-01-01

Graft fixation is important for graft take. Fibrin glue has been proposed as an ideal material, because of its human origin and it provides firm adhesion in seconds or minutes. To evaluate the efficiency of fibrin glue, in increasing the take of skin graft. Assessment includes surgical time taken for graft fixation, haematoma/seroma formation, engraftment and wound closure by day 14. The study is an observational prospective study conducted in the Department of Plastic Surgery, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, from January 2016 to June 2016. Sixteen patients who underwent split skin grafting were assessed during the study period. Fibrin glue was used on the recipient bed before grafting. Better haemostasis and graft adhesion, with a significant reduction of surgical time, were noted. The safety profile of fibrin glue was excellent as indicated by the lack of any related serious adverse experiences. These findings demonstrate that it is safe and effective for attachment of skin grafts, with outcomes at least as good as conventional methods.

Development of tissue-engineered self-expandable aortic stent grafts (Bio stent grafts) using in-body tissue architecture technology in beagles.

Science.gov (United States)

Kawajiri, Hidetake; Mizuno, Takeshi; Moriwaki, Takeshi; Ishibashi-Ueda, Hatsue; Yamanami, Masashi; Kanda, Keiichi; Yaku, Hitoshi; Nakayama, Yasuhide

2015-02-01

In this study, we aimed to describe the development of tissue-engineered self-expandable aortic stent grafts (Bio stent graft) using in-body tissue architecture technology in beagles and to determine its mechanical and histological properties. The preparation mold was assembled by insertion of an acryl rod (outer diameter, 8.6 mm; length, 40 mm) into a self-expanding nitinol stent (internal diameter, 9.0 mm; length, 35 mm). The molds (n = 6) were embedded into the subcutaneous pouches of three beagles for 4 weeks. After harvesting and removing each rod, the excessive fragile tissue connected around the molds was trimmed, and thus tubular autologous connective tissues with the stent were obtained for use as Bio stent grafts (outer diameter, approximately 9.3 mm in all molds). The stent strut was completely surrounded by the dense collagenous membrane (thickness, ∼150 µm). The Bio stent graft luminal surface was extremely flat and smooth. The graft wall of the Bio stent graft possessed an elastic modulus that was almost two times higher than that of the native beagle abdominal aorta. This Bio stent graft is expected to exhibit excellent biocompatibility after being implanted in the aorta, which may reduce the risk of type 1 endoleaks or migration. © 2014 Wiley Periodicals, Inc.

Genome-wide identification and comparative analysis of grafting-responsive mRNA in watermelon grafted onto bottle gourd and squash rootstocks by high-throughput sequencing.

Science.gov (United States)

Liu, Na; Yang, Jinghua; Fu, Xinxing; Zhang, Li; Tang, Kai; Guy, Kateta Malangisha; Hu, Zhongyuan; Guo, Shaogui; Xu, Yong; Zhang, Mingfang

2016-04-01

Grafting is an important agricultural technique widely used to improve plant growth, yield, and adaptation to either biotic or abiotic stresses. However, the molecular mechanisms underlying grafting-induced physiological processes remain unclear. Watermelon (Citrullus lanatus L.) is an important horticultural crop worldwide. Grafting technique is commonly used in watermelon production for improving its tolerance to stresses, especially to the soil-borne fusarium wilt disease. In the present study, we used high-throughput sequencing to perform a genome-wide transcript analysis of scions from watermelon grafted onto bottle gourd and squash rootstocks. Our transcriptome and digital gene expression (DGE) profiling data provided insights into the molecular aspects of gene regulation in grafted watermelon. Compared with self-grafted watermelon, there were 787 and 3485 genes differentially expressed in watermelon grafted onto bottle gourd and squash rootstocks, respectively. These genes were associated with primary and secondary metabolism, hormone signaling, transcription factors, transporters, and response to stimuli. Grafting led to changes in expression of these genes, suggesting that they may play important roles in mediating the physiological processes of grafted seedlings. The potential roles of the grafting-responsive mRNAs in diverse biological and metabolic processes were discussed. Obviously, the data obtained in this study provide an excellent resource for unraveling the mechanisms of candidate genes function in diverse biological processes and in environmental adaptation in a graft system.

Intraarterial 9-beta-methyl carbacyclin improves canine polytetrafluoroethylene graft patency

International Nuclear Information System (INIS)

Dacey, L.J.; Hees, P.S.; Cronenwett, J.L.

1988-01-01

This study examined the effect of 9-beta-methyl carbacyclin, a synthetic, stable prostacyclin analog, on canine polytetrafluoroethylene (PTFE) graft patency. Twenty-five dogs had 4 mm x 7 cm PTFE grafts implanted bilaterally into the femoral arteries. A subcutaneous infusion pump was used to deliver either saline solution (control) or 9-beta-methyl carbacyclin (Ciprostine) at 100 (CARB-100) or 200 ng/kg/min (CARB-200) through a femoral artery branch just proximal to one of the femoral grafts, with the contralateral graft serving as a noninfused control. Graft-platelet deposition (with 111 In-labeled platelets) was measured between the fifth and seventh days, with patency determined on the seventh day. Dogs were classified as aggregators (AGG [+]) if the preoperative epinephrine-enhanced sodium arachidonate platelet aggregation was greater than 20%. CARB-200 infusion significantly improved ipsilateral graft patency (80%) compared with noninfused grafts (50%, p less than 0.05), or grafts in control and CARB-100 dogs (43%, p less than 0.05). Anastomotic platelet deposition was decreased bilaterally in CARB-200 dogs by 45% to 59% compared with CARB-100 and control dogs (p less than 0.05). With the exception of grafts infused with CARB-200, AGG (+) dogs had significantly lower graft patency (26%) than nonaggregator AGG (-) dogs (71%, p less than 0.01). CARB-200 infusion significantly improved graft patency in AGG (+) dogs (71%), compared with control and CARB-100-infused grafts (19%, p less than 0.025). Intra-arterial 9-beta-methyl carbacyclin improved early PTFE graft patency and inhibited platelet deposition in a severe canine model, independent of baseline platelet aggregation status, which also had an important effect on graft patency

Tissue Responses to Stent Grafts with Endo-Exo-Skeleton for Saccular Abdominal Aortic Aneurysms in a Canine Model

Energy Technology Data Exchange (ETDEWEB)

Kim, Il Young; Chung, Jin Wook; Kim, Hyo Cheol [Dept. of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, Clinical Research Institute, Seoul (Korea, Republic of); Choi, Young Ho; So Young Ho [Dept. of Radiology, Seoul National University Boramae Hospital, Seoul (Korea, Republic of); Kim, Hyun Beom [Dept. of Radiology, National Cancer Center, Goyang (Korea, Republic of); Min, Seung Kee [Dept. of Surgery, Seoul National University College of Medicine, Seoul (Korea, Republic of); Park, Jae Hyung [Dept. of Radiology, Gachon University Gil Medical Center, Incheon (Korea, Republic of)

2014-10-15

We evaluated the effect of close contact between the stent and the graft on the induction of endothelial covering on the stent graft placed over an aneurysm. Saccular abdominal aortic aneurysms were made with Dacron patch in eight dogs. The stent graft consisted of an inner stent, a expanded polytetrafluoroethylene graft, and an outer stent. After sacrificing the animals, the aortas with an embedded stent graft were excised. The aortas were inspected grossly and evaluated microscopically. The animals were sacrificed at two (n = 3), six (n = 3), and eight months (n = 2) after endovascular repair. In two dogs, the aortic lumen was occluded at two months after the placement. On gross inspection of specimens from the other six dogs with a patent aortic lumen, stent grafts placed over the normal aortic wall were covered by glossy white neointima, whereas, stent grafts placed over the aneurysmal aortic wall were covered by brownish neointima. On microscopic inspection, stent grafts placed over the normal aortic wall were covered by thin neointima (0.27 ± 0.05 mm, mean ± standard deviation) with an endothelial layer, and stent grafts placed over the aneurysmal aortic wall were covered by thick neointima (0.62 ± 0.17 mm) without any endothelial lining. Transgraft cell migration at the normal aortic wall was more active than that at the aneurysmal aortic wall. Close contact between the stent and the graft, which was achieved with stent grafts with endo-exo-skeleton, could not enhance endothelial covering on the stent graft placed over the aneurysms.

Laser-assisted fibrinogen bonding of umbilical vein grafts.

Science.gov (United States)

Oz, M C; Williams, M R; Souza, J E; Dardik, H; Treat, M R; Bass, L S; Nowygrod, R

1993-06-01

Despite success with autologous tissue welding, laser welding of synthetic vascular prostheses has not been possible. The graft material appears inert and fails to allow the collagen breakdown and electrostatic bonding that results in tissue welding. To develop a laser welding system for graft material, we repaired glutaraldehyde-tanned human umbilical cord vein graft incisions using laser-assisted fibrinogen bonding (LAFB) technology. Modified umbilical vein graft was incised transversely (1.2 cm). Incisions were repaired using sutures, laser energy alone, or LAFB. For LAFB, indocyanine green dye was mixed with human fibrinogen and the compound applied with forceps onto the weld site prior to exposure to 808 nm diode laser energy (power density 4.8 W/cm 2). Bursting pressures for sutured repairs (126.6 +/- 23.4 mm Hg) were similar to LAFB anastomoses (111.6 +/- 55.0 mm Hg). No evidence of collateral thermal injury to the graft material was noted. In vivo evaluation of umbilical graft bonding with canine arteries demonstrates that LAFB can reliably reinforce sutured anastomoses. The described system for bonding graft material with laser exposed fibrinogen may allow creation or reinforcement of vascular anastomoses in procedures where use of autologous tissue is not feasible.

A Review on Grafting of Biofibers for Biocomposites.

Science.gov (United States)

Wei, Liqing; McDonald, Armando G

2016-04-22

A recent increase in the use of biofibers as low-cost and renewable reinforcement for the polymer biocomposites has been seen globally. Biofibers are classified into: lignocellulosic fibers ( i.e. , cellulose, wood and natural fibers), nanocellulose ( i.e. , cellulose nanocrystals and cellulose nanofibrils), and bacterial cellulose, while polymer matrix materials can be petroleum based or bio-based. Green biocomposites can be produced using both biobased fibers and polymers. Incompatibility between the hydrophilic biofibers and hydrophobic polymer matrix can cause performance failure of resulting biocomposites. Diverse efforts have focused on the modification of biofibers in order to improve the performances of biocomposites. "Grafting" copolymerization strategy can render the advantages of biofiber and impart polymer properties onto it and the performance of biocomposites can be tuned through changing grafting parameters. This review presents a short overview of various "grafting" methods which can be directly or potentially employed to enhance the interaction between biofibers and a polymer matrix for biocomposites. Major grafting techniques, including ring opening polymerization, grafting via coupling agent and free radical induced grafting, have been discussed. Improved properties such as mechanical, thermal, and water resistance have provided grafted biocomposites with new opportunities for applications in specific industries.

Morphological observation, RNA-Seq quantification, and expression profiling: novel insight into grafting-responsive carotenoid biosynthesis in watermelon grafted onto pumpkin rootstock.

Science.gov (United States)

Liu, Guang; Yang, Xingping; Xu, Jinhua; Zhang, Man; Hou, Qian; Zhu, Lingli; Huang, Ying; Xiong, Aisheng

2017-03-01

Watermelon is an important and economical horticultural crop in China, where ~20% of the plants are grafted. The development of grafted watermelon fruit involves a diverse range of gene interactions that results in dynamic changes in fruit. However, the molecular mechanisms underlying grafting-induced fruit quality change are unclear. In the present study, we measured the lycopene content by high-performance liquid chromatography and used RNA-Seq (quantification) to perform a genome-wide transcript analysis of fruits from watermelon grafted onto pumpkin rootstock (pumpkin-grafted watermelon, PGW), self-grafted watermelon (SGW), and non-grafted watermelon (NGW). The results showed variation in the lycopene content in the flesh of PGW fruits, first increasing and then decreasing in the four stages, which was different from the trend in the flesh of NGW and SGW fruits. The transcriptome profiling data provided new information on the grafting-induced gene regulation of lycopene biosynthesis during fruit growth and development. The expression levels of 33 genes from 8 gene families (GGPS, PSY, PDS, ZDS, CRTISO, LCYb, LCYe, and CHY) related to lycopene biosynthesis, which play critical roles in fruit coloration and contribute significantly to fruit phytonutrient values, were monitored during the four periods of fruit development in watermelon. Compared with those of NGW and SGW, 14 genes were differentially expressed in PGW during fruit development, suggesting that these genes possibly help to mediate lycopene biosynthesis in grafted watermelon fruit. Our work provides some novel insights into grafting-responsive carotenoid metabolism and its potential roles during PGW fruit development and ripening. © The Author 2016. Published by Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Sulfonated hydrocarbon graft architectures for cation exchange membranes

DEFF Research Database (Denmark)

Nielsen, Mads Møller; Jankova Atanasova, Katja; Hvilsted, Søren

2013-01-01

A synthetic strategy to hydrocarbon graft architectures prepared from a commercial polysulfone and aimed as ion exchange membrane material is proposed. Polystyrene is grafted from a polysulfone macroinitiator by atom transfer radical polymerization, and subsequently sulfonated with acetyl sulfate...... to various degrees. Series of grafting densities and graft lengths are prepared, and membranes are solvent cast from DMSO. The membrane properties in aqueous environments are evaluated from their water swelling behavior, and their thermal properties and stability are investigated by thermogravimetric...

History of free skin grafting. Knowledge of empiricism?

OpenAIRE

Klasen, Hendrik Jan

1981-01-01

In the course of more than a hundred years, skin grafting has become a standard procedure in surgery. The indications for the several types of grafting have become rather uniform.The technical aids at the operations only differ in details. Especially the vast experience gained in World War II provided the opportunity to develop the technique of skin grafting and so the evolution of present day plastics surgery. However, virtually every step in the field of indications, selection of grafts, te...

Functional activity of substantia nigra grafts reinnervating the striatum: neurotransmitter metabolism and (14C)2-deoxy-D-glucose autoradiography. [Rats

Energy Technology Data Exchange (ETDEWEB)

Schmidt, R H; Ingvar, M; Lindvall, O; Stenevi, U; Bjoerklund, A

1982-03-01

Dopaminergic innervation of the caudate nucleus in adult rats can be partially restored by the grafting of embryonic substantia nigra into the overlying parietal cortex with concomitant compensation of certain behavioral abnormalities. In this study the function of such grafts was investigated neurochemically by quantification of transmitter metabolism and glucose utilization in the reinnervated target. Rats with unilateral 6-hydroxydopamine lesions of the nigrostriatal bundle received a single graft to the dorsal caudate-putamen and were screened for rotational behavior following 5 mg/kg methamphetamine. The grafts restored dopamine concentrations in the caudate-putamen from initially less than 0.5% to an average of 13.6% of normal in rats with behavioral compensation. The ratio of 3,4-dihydroxyphenylacetic acid to dopamine, which is a measure of the rate of transmitter turnover, were equivalent in transplanted and normal control rats. Moreover, measurements of DOPA accumulation for a 30-min period after DOPA decarboxylase inhibition indicated similar fractional dopamine turnover rates in normal and transplant-reinnervated tissues. Correlations between rotational behavior and dopamine concentrations showed that reinnervation to only 3% of normal was sufficient to counterbalance the motor asymmetry. Measurements of glucose utilization by (14C)deoxyglucose autoradiography indicated equivalent metabolic rates for the grafted tissue and the intact substantia nigra. Overall the results indicate that behaviorally functional neuronal grafts spontaneously metabolize dopamine and utilize glucose at rates characteristic of the intact nigrostriatal system. This provides further evidence that ectopic intracortical nigral transplants can reinstate dopaminergic neurotransmission in regions of the host brain initially denervated by the 6-hydroxydopamine lesion.

Hot callusing for propagation of American beech by grafting

Science.gov (United States)

David W. Carey; Mary E. Mason; Paul Bloese; Jennifer L. Koch

2013-01-01

To increase grafting success rate, a hot callus grafting system was designed and implemented as part of a multiagency collaborative project to manage beech bark disease (BBD) through the establishment of regional BBD-resistant grafted seed orchards. Five years of data from over 2000 hot callus graft attempts were analyzed using a logistic regression model to determine...

Long-term results of 2-mm punch grafting in patients with vitiligo vulgaris and segmental vitiligo: effect of disease activity

NARCIS (Netherlands)

Fongers, A.; Wolkerstorfer, A.; Nieuweboer-Krobotova, L.; Krawczyk, P.; Tóth, G. G.; van der Veen, J. P. W.

2009-01-01

Background Punch grafting is a simple and frequently used technique for the treatment of stable vitiligo, resistant to medical therapy. However, studies reporting long-term results are exceptional. Objectives To evaluate the long-term results of 2-mm punch grafting in patients with vitiligo vulgaris

Long-term results of 2-mm punch grafting in patients with vitiligo vulgaris and segmental vitiligo : effect of disease activity

NARCIS (Netherlands)

Fongers, A.; Wolkerstorfer, A.; Nieuweboer-Krobotova, L.; Krawczyk, P.; Toth, G. G.; van der Veen, J. P. W.

Background Punch grafting is a simple and frequently used technique for the treatment of stable vitiligo, resistant to medical therapy. However, studies reporting long-term results are exceptional. Objectives To evaluate the long-term results of 2-mm punch grafting in patients with vitiligo vulgaris

Long-term results of 2-mm punch grafting in patients with vitiligo vulgaris and segmental vitiligo : effect of disease activity

NARCIS (Netherlands)

Fongers, A.; Wolkerstorfer, A.; Nieuweboer-Krobotova, L.; Krawczyk, P.; Toth, G. G.; van der Veen, J. P. W.

2009-01-01

Background Punch grafting is a simple and frequently used technique for the treatment of stable vitiligo, resistant to medical therapy. However, studies reporting long-term results are exceptional. Objectives To evaluate the long-term results of 2-mm punch grafting in patients with vitiligo vulgaris

SOME TECHNIQUES IN CORNEAL GRAFTING

African Journals Online (AJOL)

1971-04-10

Apr 10, 1971 ... current herpes corneae. The visual acuity was less than. 6/60. The left eye had had a central nebula since child- hood and was deemed amblyopic. Six weeks after a 7 x 0·3 mm lamellar graft in the right eye was placed, ulceration occurred in the graft junction. A total thin conjunctival flap was sutured over.

Application of platelet-rich plasma and platelet-rich fibrin in fat grafting: basic science and literature review.

Science.gov (United States)

Liao, Han-Tsung; Marra, Kacey G; Rubin, J Peter

2014-08-01

Due to the natural properties of fat, fat grafting remains a popular procedure for soft tissue volume augmentation and reconstruction. However, clinical outcome varies and is technique dependent. Platelet-rich plasma (PRP) contains α-granules, from which multiple growth factors such as platelet-derived growth factor, transforming growth factor-β, vascular endothelial growth factor, and epidermal growth factor can be released after activation. In recent years, the scope of PRP therapies has extended from bone regeneration, wound healing, and healing of musculoskeletal injuries, to enhancement of fat graft survival. In this review, we focus on the definition of PRP, the different PRP preparation and activation methods, and growth factor concentrations. In addition, we discuss possible mechanisms for the role of PRP in fat grafting by reviewing in vitro studies with adipose-derived stem cells, preadipocytes, and adipocytes, and preclinical and clinical research. We also review platelet-rich fibrin, a so-called second generation PRP, and its slow-releasing biology and effects on fat grafts compared to PRP in both animal and clinical research. Finally, we provide a general foundation on which to critically evaluate earlier studies, discuss the limitations of previous research, and direct plans for future experiments to improve the optimal effects of PRP in fat grafting.

Dynamics of solvent-free grafted nanoparticles

KAUST Repository

Chremos, Alexandros; Panagiotopoulos, Athanassios Z.; Koch, Donald L.

2012-01-01

as well as grafted nanoparticles in a melt were compared to a reference system of bare (ungrafted) particles in a melt. Whereas longer chains lead to a larger hydrodynamic radius and lower relative diffusivity for grafted particles in a melt, bulk solvent

Enhancing both the mechanical and chemical properties of paper sheet by graft co-polymerization with acrylonitrile/methyl methacrylate

Directory of Open Access Journals (Sweden)

H.M. Abd El Salam

2014-09-01

Full Text Available The chemical graft copolymerization reaction of acrylonitrile (AN and methyl methacrylate (MMA binary mixture onto paper sheet was performed. The effect of initiator concentration, monomer concentration and temperature on the reaction rate was studied. The reaction rate equation of the graft copolymerization reaction is found to be RP = K2 [Initiator]0.795[Monomer]2.007. The apparent activation energy (Ea of the copolymerization reaction is found to be 75.01 kJ/mol. The infrared characteristic absorption bands for cellulosic paper structure and the paper gr-AN-MMA are investigated. Tensile break load, porosity and burst strength were measured for the grafted and pure paper sheet. It was found that the mechanical properties are improved by grafting copolymerization. The chemical resistance of the graft product against a strong acid a strong alkali, polar and nonpolar solvents was investigated. It was found that the resistance to these chemicals is enhanced by grafting.

Sacral Fracture Nonunion Treated by Bone Grafting through a Posterior Approach

Directory of Open Access Journals (Sweden)

Sang Yang Lee

2013-01-01

Full Text Available Nonunion of a sacral fracture is a rare but serious clinical condition which can cause severe chronic pain, discomfort while sitting, and significant restriction of the level of activities. Fracture nonunions reportedly occur most often after nonoperative initial treatment or inappropriate operative treatment. We report a case of fracture nonunion of the sacrum and pubic rami that resulted from non-operative initial treatment, which was treated successfully using bone grafting through a posterior approach and CT-guided percutaneous iliosacral screw fixation combined with anterior external fixation. Although autologous bone grafting has been the gold standard for the treatment of pelvic fracture nonunions, little has been written describing the approach. We utilized a posterior approach for bone grafting, which could allow direct visualization of the nonunion site and preclude nerve root injury. By this procedure, we were able to obtain the healing of fracture nonunion, leading to pain relief and functional recovery.

The influence of Australian eye banking practices on corneal graft survival.

Science.gov (United States)

Keane, Miriam C; Lowe, Marie T; Coster, Douglas J; Pollock, Graeme A; Williams, Keryn A

2013-08-19

To identify eye banking practices that influence corneal graft survival. Prospective cohort study of records of 19,254 followed corneal grafts in 15160 patients, submitted to the Australian Corneal Graft Registry between May 1985 and July 2012. Influence of corneal preservation method (organ culture, moist pot, Optisol, other); death-to-enucleation, death-to-preservation and enucleation-to-graft times; transportation by air; graft era; and indication for graft on probability of graft survival at most recent follow-up. In multivariate analysis, 919 penetrating grafts performed using corneas transported interstate by air exhibited worse survival than 14,684 grafts performed using corneas retrieved and used locally (hazard ratio [HR], 1.44; 95% CI, 1.21-1.73; P = 0.001). This was also the case for traditional lamellar grafts (64 corneas transported by air and 813 used locally; HR, 1.69; 95% CI, 1.03-2.78; P = 0.038). Indication for graft influenced survival of penetrating grafts (4611 keratoconus, 727 emergency or high-risk, 10,265 other indication; global P < 0.001) and traditional lamellar grafts (65 keratoconus, 212 emergency or high-risk, 600 other indication; global P < 0.001). The preservation medium in which corneas used for traditional lamellar grafts were stored exerted a marginal influence on graft survival (global P = 0.047). Donor corneas transported interstate exhibited poorer survival after transplantation than those retrieved and grafted locally. Higher proportions of emergency procedures involving transported corneas did not account for this difference. Where possible, efforts to avoid transportation of corneal tissue by air freight within Australia may be warranted.

Comprehensive Mineral Nutrition Analysis of Watermelon Grafted onto Two Different Rootstocks

Directory of Open Access Journals (Sweden)

Yuan Huang

2016-03-01

Full Text Available Grafting is a widely used practice in fruit-bearing vegetables. However, why grafting affects plant growth, fruit yield, and quality, especially from the aspect of mineral nutrition, remains unclear. In this study, watermelon cultivar ‘Zaojia 8424’ was grafted onto bottle gourd ‘Jingxinzhen 1’ (Lagenaria siceraria and pumpkin ‘Qingyanzhen 1’ (Cucurbita maxima × C. moschata. Non-grafted plants were used as the control. Results show that rootstock grafting significantly increases plant growth and single fruit weight of watermelon. Watermelon grafted onto rootstocks, especially pumpkin, exhibits significantly higher root volume, root surface area, and number of root tips and forks in comparison with non-grafted plants. Fruit flesh, rind firmness, and rind thickness were enhanced by grafting. However, fruit soluble solids and taste significantly decreased in plants grafted onto pumpkin. The total uptake (mg ⋅ plant−1 and concentration (mg ⋅ g−1 DW of N, K, Ca, Fe, Mg, and Mn in root, stem, leaf, fruit rind, and flesh were generally higher in grafted plants compared to non-grafted ones, especially for N of pumpkin rootstock-grafted plants. The total uptake of nutrients of plants grafted onto bottle gourd and pumpkin was increased by 30.41% and 49.14% at fruit development stage and by 21.33% and 47.46% at fruit maturation stage, respectively, compared with non-grafted plants. We concluded that watermelon grafting onto suitable rootstocks can increase the uptake of mineral nutrition, especially for N in the pumpkin rootstock grafted plants, thereby affecting plant growth, fruit yield, and quality.

Composite vascular grafts with high cell infiltration by co-electrospinning

International Nuclear Information System (INIS)

Tan, Zhikai; Wang, Hongjie; Gao, Xiangkai; Liu, Tong; Tan, Yongjun

2016-01-01

There is an increasing demand for functional small-diameter vascular grafts (diameter < 6 mm) to be used in clinical arterial replacement. An ideal vascular graft should have appropriate biomechanical properties and be biocompatible. Electrospinning has become a popular polymer processing technique for vascular tissue engineering, but the grafts fabricated by electrospinning often have relatively small pores and low porosity, which limit cell infiltration into scaffolds and hinder the regeneration and remodeling of grafts. In the present study, we aimed to develop an efficient method to prepare electrospun composite vascular grafts comprising natural and synthetic materials. We fabricated grafts made of polycaprolactone, gelatin, and polyvinyl alcohol (PVA) by co-electrospinning, and the scaffolds were further functionalized by immobilizing heparin on them. The PVA fibers degraded rapidly in vivo and generated electrospun scaffolds with high porosity, which significantly enhanced cell proliferation and infiltration. The mechanical properties of the grafts are suitable for use in artery replacement. Heparin functionalization of the grafts yielded a good antithrombogenic effect, which was demonstrated in platelet adhesion tests. Moreover, in vitro and in vivo results demonstrated that the heparin release from the grafts enhanced the growth of endothelial cells, which is important for the endothelium of implanted grafts. The results of this study indicate that our method is effective and controllable for the fabrication of vascular grafts that meet the clinical requirements for blood vessel transplantation. - Highlights: • This study indicate an effective method for the fabrication of vascular grafts that meet the clinical requirements. • Co-electrospinning were used to fabricate grafts made of polycaprolactone (PCL), gelatin (GT), and polyvinyl alcohol (PVA). • PVA was used to create large pores within the hybrid scaffolds, thereby enhancing cell infiltration

Composite vascular grafts with high cell infiltration by co-electrospinning

Energy Technology Data Exchange (ETDEWEB)

Tan, Zhikai, E-mail: tanzk@hnu.edu.cn; Wang, Hongjie; Gao, Xiangkai; Liu, Tong; Tan, Yongjun

2016-10-01

There is an increasing demand for functional small-diameter vascular grafts (diameter < 6 mm) to be used in clinical arterial replacement. An ideal vascular graft should have appropriate biomechanical properties and be biocompatible. Electrospinning has become a popular polymer processing technique for vascular tissue engineering, but the grafts fabricated by electrospinning often have relatively small pores and low porosity, which limit cell infiltration into scaffolds and hinder the regeneration and remodeling of grafts. In the present study, we aimed to develop an efficient method to prepare electrospun composite vascular grafts comprising natural and synthetic materials. We fabricated grafts made of polycaprolactone, gelatin, and polyvinyl alcohol (PVA) by co-electrospinning, and the scaffolds were further functionalized by immobilizing heparin on them. The PVA fibers degraded rapidly in vivo and generated electrospun scaffolds with high porosity, which significantly enhanced cell proliferation and infiltration. The mechanical properties of the grafts are suitable for use in artery replacement. Heparin functionalization of the grafts yielded a good antithrombogenic effect, which was demonstrated in platelet adhesion tests. Moreover, in vitro and in vivo results demonstrated that the heparin release from the grafts enhanced the growth of endothelial cells, which is important for the endothelium of implanted grafts. The results of this study indicate that our method is effective and controllable for the fabrication of vascular grafts that meet the clinical requirements for blood vessel transplantation. - Highlights: • This study indicate an effective method for the fabrication of vascular grafts that meet the clinical requirements. • Co-electrospinning were used to fabricate grafts made of polycaprolactone (PCL), gelatin (GT), and polyvinyl alcohol (PVA). • PVA was used to create large pores within the hybrid scaffolds, thereby enhancing cell infiltration

Intravascular stent graft with polyurethane and metallic stent: experimental study

International Nuclear Information System (INIS)

Do, Young Soo; Lee, Won Jae; Kim, Boo Kyung Han; Park, Jae Hyung; Lee, Hak Jong; Lee, Sang Hyun; Kim, Sung Hyun; Kim, Jong Won; Ha, Jongwon

1997-01-01

To evaluate the usefulness of a new model of the stent graft, and of tissue response related to placement of the stent graft. The stent graft was constructed from polyurethane (Pellethane) graft and Hanaro stent(12mm in diameter, 45mm in length, 10 bends). A stent grafts was inserted into the lower thoracic aorta in each of six adult mongrel dogs(body weight, 12-16kg). At one, two, four, and six months, follow-up studies of angiography and spiral CT angiography were preformed to evaluate wascular patency, vascular stenosis, and thrombus formation. Two dogs were sacrificed at 1month, 2months, and 6months after insertion of the stent graft and macroscopic, light microscopic, and scanning electron microscopic examinations of the aortic segment including the stent graft were performed to evaluate intimal hyperplasia, endothelial growth to the graft, and thrombus formation. During follow-up at one, two, four, and six months, angiography or spiral CT angiography showed 20-100% luminal stenosis or occlusion of the lower thoracic aorta by the thrombus and perigraft leaks in three dogs(50%), and collateral vessels caused by occlusion of the aorta in two (33.3%). On gross examination, there were thrombi of 1-5mm thickness at the graft portions in all dogs, and this thickness gradually increased. The mean thickness of intimal hyperplasia at the stent portion gradually increased from 120μm to 227μm and the mean thickness of intimal hyperplasia at the graft portion from 93μm to 914μm. This thickness was greater at the graft portion than at the stent portion. Scanning electron microscopy showed elliptical endothelial lining on the neointimal surfaces at each end of the graft. Thrombi caused stenosis or occlusion of the stent graft. In order for such a graft to be ideal, further study is needed

Descemet Stripping Automated Endothelial Keratoplasty for Failed Penetrating Keratoplasty: Influence of the Graft-Host Junction on the Graft Survival Rate.

Science.gov (United States)

Omoto, Takashi; Sakisaka, Toshihiro; Toyono, Tetsuya; Yoshida, Junko; Shirakawa, Rika; Miyai, Takashi; Yamagami, Satoru; Usui, Tomohiko

2018-04-01

To investigate the clinical results of Descemet stripping automated endothelial keratoplasty (DSAEK) for failed penetrating keratoplasty (PK) and the influence of the graft-host junction (GHJ) on the graft survival rate. Data were retrospectively collected on patient demographics, visual outcomes, complications, and graft survival rate for 17 eyes of 16 patients who underwent DSAEK for failed PK. The graft survival rate was compared between the eyes when divided into a bump group and a well-aligned group according to the shape of the GHJ detected on anterior segment optical coherence tomography. The most common indication for initial PK was bullous keratopathy after glaucoma surgery (35.3%). Seven eyes (41.2%) were classified into the bump group and 10 eyes (58.8%) into the well-aligned group. The mean best-ever documented visual acuity (BDVA) after DSAEK was 0.33 logMAR. Postoperatively, almost 70% of eyes achieved a BDVA that was within 0.2 logMAR of their preoperative BDVA. Graft detachment occurred in 29.4% of eyes and primary graft failure in 17.6%. All primary failures occurred in the bump group. The cumulative graft survival rate was 82.3% at 1 year, 73.2% at 2 years, and 58.6% at 3 years. Graft failure was more likely in eyes in the bump group than in those in the well-aligned group (P = 0.037, Wilcoxon test). DSAEK for failed PK had a favorable outcome in this study. However, the GHJ should be assessed carefully before performing the procedure.

The effect of carbon dioxide therapy on composite graft survival.

Science.gov (United States)

Durães, Eliana Ferreira Ribeiro; Durães, Leonardo de Castro; Carneiro, Fabiana Pirani; Lino, Ruy de Souza; Sousa, João Batista de

2013-08-01

To investigate the effect of carboxytherapy in auricular composite grafts in rabbits. An experimental study was conducted using 20 rabbits randomly assigned to a treatment group of carboxytherapy or a control group of saline solution. In each ear, a circular graft with 1.5 cm or 2 cm of diameter was amputated and reattached. Animals underwent carbon dioxide or saline injection four times during the experiment. We analyzed clinical evolution of the animals, grafts survival, histopathology features and histomorphometry of collagen. The treated group had a significantly lower weight gain (p=0.038). Histopathology was not significantly different between groups. There was an increase in amount of collagen in 2 cm grafts submitted to carbon dioxide therapy (p=0.003). Carboxytherapy didn't influence graft survival rate for 1.5 cm grafts or 2 cm grafts (p=0.567 and p=0.777, respectively). Carbon dioxide therapy increased the amount of collagen in 2 cm grafts. CO2 was not significantly different from saline infusion on composite grafts survival, but this study suggests that there is a mechanical effect caused by distension which favored graft survival.

Synthesis of Radiation Grafted Polymer Matrices for Separation and Industrial Applications

Energy Technology Data Exchange (ETDEWEB)

Bhardwaj, Y K; Virendra, K; Goel, N K; Sarma, K S.S.; Sabharwal, S [Radiation Technology Development Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085 (India)

2012-09-15

Grafting of acrylonitrile onto non-woven porous polypropylene fibre sheet using electron beam was carried out by post-irradiation grafting. Grafting extent of {approx}125% was achieved. The grafted nitrile groups were amidoximated and studied for uranium uptake from sea water and heavy metal ions (Co{sup 2+}, Ni{sup 2+}, Mn{sup 2+}, and Cd{sup 2+}) from aqueous solutions. Adsorption and elution of adsorbed ions in suitable eluents was studied. The grafting process was upgraded to pilot scale to obtain 1x1 m{sup 2} sheets. Mutual radiation grafting technique was used for grafting of vinylbenzyltrimethyl ammonium chloride, [2- (methacryloyloxy)ethyl] trimethylammonium chloride and [2-(acryloyloxyethyl)]trimethylammonium chloride onto cotton cellulose substrate. The grafted matrices showed significantly higher water uptake and good water retention properties. The antibacterial efficacy of the grafted products was found to be a function of extent of grafting and the type of bacteria (Escherichia coli, Pseudomonas flourescens, Staphylococcus aureus and Bacillus cereus). PVBT-g-cotton was studied for its protein adsorption behaviour in continuous column process using Bovine serum albumin (BSA) as a model protein. Mutual radiation grafting technique was used to graft acrylic acid on micrometer thick micro-porous polypropylene membrane. Contact angle measurement studies showed that initial grafting as well as radiation treatment of poly(propylene) in aqueous medium and in presence of Mohr's salt enhances its affinity towards the grafting solution. The enhancement in the polar component of surface energy of treated polypropylene membrane is the primary cause of grafting enhancement. The membranes grafted to an extent of {approx}20% were found to perform comparably with the battery separator presently being used by battery industry. Acrylic acid was grafted to Teflon scrap by mutual radiation grafting technique. The grafting extent decreased with increasing dose rate and

Pinch grafting for chronic venous leg ulcers in general practice

OpenAIRE

Steele, Keith

1985-01-01

Twenty-five patients with chronic venous leg ulcers were treated in general practice by pinch grafting. Fifteen of the ulcers (60%) were completely healed one year after grafting. Prior to grafting 19 patients (76%) complained of daily pain in the ulcer. These patients experienced complete relief from pain after grafting. Pinch grafting is a simple, safe and effective therapy when applied in a domiciliary environment.

Kinetic investigations of graft copolymerization of sodium styrene sulfonate onto electron beam irradiated poly(vinylidene fluoride) films

Energy Technology Data Exchange (ETDEWEB)

Mahmoud Nasef, Mohamed, E-mail: mahmoudeithar@fkkksa.utm.m [Institute of Hydrogen Economy, International City Campus, Universiti Teknologi Malaysia, Jalan Semarak, 54100 Kuala Lumpur (Malaysia); Chemical Engineering Department, Faculty of Chemical and Natural Resources Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia); Saidi, Hamdani [Institute of Hydrogen Economy, International City Campus, Universiti Teknologi Malaysia, Jalan Semarak, 54100 Kuala Lumpur (Malaysia); Chemical Engineering Department, Faculty of Chemical and Natural Resources Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia); Mohd Dahlan, Khairul Zaman [Radiation Processing Technology Division, Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia)

2011-01-15

Graft copolymerization of sodium styrene sulfonate (SSS) onto electron beam (EB) irradiated poly(vinylidene fluoride) (PVDF) films was investigated to find out a simple preparation process for sulfonic acid proton exchange membranes with respect to monomer concentration, absorbed dose, temperature, film thickness and storage time. The reaction order of the monomer concentration and absorbed dose of grafting was found to be 2.84 and 1.20, respectively. The overall activation energy for graft copolymerization reaction was calculated to be 11.36 kJ/mol. The initial rate of grafting was found to decrease with an increase in the film thickness. The trapped radicals in the irradiated PVDF films remained effective in initiating the reaction without considerable loss in grafting level up to 180 days, when stored under -60 {sup o}C. The presence and distribution of polystyrene sulfonate grafts in the obtained membranes were observed by Fourier transform infrared (FTIR) spectroscopic analysis, scanning optical microscope and scanning transmission electron microscopy (STEM) coupled with X-ray energy dispersive (EDX), respectively.

The caudal septum replacement graft.

Science.gov (United States)

Foda, Hossam M T

2008-01-01

To describe a technique for reconstructing the lost tip support in cases involving caudal septal and premaxillary deficiencies. The study included 120 patients with aesthetic and functional nasal problems resulting from the loss of caudal septal and premaxillary support. An external rhinoplasty approach was performed to reconstruct the lost support using a cartilaginous caudal septum replacement graft and premaxillary augmentation with Mersilene mesh. The majority of cases (75%) involved revisions in patients who had previously undergone 1 or more nasal surgical procedures. A caudal septum replacement graft was combined with premaxillary augmentation in 93 patients (77.5%). The mean follow-up period was 3 years (range, 1-12 years). The technique succeeded in correcting the external nasal deformities in all patients and resulted in a significant improvement in breathing in 74 patients (86%) with preoperative nasal obstruction. There were no cases of infection, displacement, or extrusion. The caudal septum replacement graft proved to be very effective in restoring the lost tip support in patients with caudal septal deficiency. Combining the graft with premaxillary augmentation using Mersilene mesh helped increase support and stability over long-term follow-up.

Grafting heterogeneous catalyst with gamma radiation

International Nuclear Information System (INIS)

Garnett, J.L.; Long, M.A.; Levot, R.G.

1984-01-01

A process for the production of a heterogeneous catalyst comprises the steps of: irradiating an organic macromolecular substrate or a metal substrate with ionising or ultra violet radiation in the presence of a monomer selected from the group consisting of o-, m-, or p- styryl diphenyl phosphine and o-, m- or p- phenyl acrylyl diphenyl phosphine, to graft the monomer to the substrate; and reacting the graft copolymer with a homogeneous catalyst selected from the group consisting of catalytic metal salts and catalytic organometallic complexes such that the graft copolymer conjugate becomes a ligand of the catalyst

Abscisic Acid-Induced H2O2 Accumulation Enhances Antioxidant Capacity in Pumpkin-Grafted Cucumber Leaves under Ca(NO3)2 Stress

Science.gov (United States)

Shu, Sheng; Gao, Pan; Li, Lin; Yuan, Yinghui; Sun, Jin; Guo, Shirong

2016-01-01

With the aim to clarifying the role of the ABA/H2O2 signaling cascade in the regulating the antioxidant capacity of grafted cucumber plants in response to Ca(NO3)2 stress, we investigated the relationship between ABA-mediated H2O2 production and the activities of antioxidant enzymes in the leaves of pumpkin-grafted cucumber seedlings. The results showed that both ABA and H2O2 were detected in pumpkin-grafted cucumber seedlings in response to Ca(NO3)2 treatment within 0.5 h in the leaves and peaked at 3 and 6 h after Ca(NO3)2 treatment, respectively, compared to the levels under control conditions. The activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), and peroxidase (POD) in pumpkin-grafted cucumber leaves gradually increased over time and peaked at 12 h of Ca(NO3)2 stress. Furthermore, in the leaves of pumpkin-grafted cucumber seedlings, the H2O2 generation, the antioxidant enzyme activities and the expression of SOD, POD and cAPX were strongly blocked by an inhibitor of ABA under Ca(NO3)2 stress, but this effect was eliminated by the addition of exogenous ABA. Moreover, the activities and gene expressions of these antioxidant enzymes in pumpkin-grafted leaves were almost inhibited under Ca(NO3)2 stress by pretreatment with ROS scavengers. These results suggest that the pumpkin grafting-induced ABA accumulation mediated H2O2 generation, resulting in the induction of antioxidant defense systems in leaves exposed to Ca(NO3)2 stress in the ABA/H2O2 signaling pathway. PMID:27746808

Use of Autologous Scleral Graft in Ahmed Glaucoma Valve Surgery.

Science.gov (United States)

Wolf, Alvit; Hod, Yair; Buckman, Gila; Stein, Nili; Geyer, Orna

2016-04-01

To compare the efficacy of an autoscleral free-flap graft versus an autoscleral rotational flap graft in Ahmed glaucoma valve (AGV) surgery. Medical records (2005 to 2012) of 51 consecutive patients (51 eyes) who underwent AGV surgery with the use of either an autoscleral free-flap graft or an autoscleral rotational flap graft to cover the external tube at the limbus were retrieved for review. The main outcome measure was the incidence of tube exposure associated with each surgical approach. Twenty-seven consecutive patients (27 eyes) received a free-flap graft and 24 consecutive patients (24 eyes) received a rotational flap graft. The mean follow-up time was 55.6 ± 18.3 months for the former and 24.2± 5 .0 months for the latter (P<0.0001). Two patients in the free-flap group (8.9%) developed tube exposure at 24 and 55 months postoperatively compared with none of the patients in the rotational flap group. Graft thinning without evidence of conjunctival erosion was observed in 15 patients (55%) in the free-flap group and in 7 patients (29.1%) in the rotational flap group. The use of an autoscleral rotational flap graft is an efficacious technique for primary tube patch grafting in routine AGV surgery, and yielded better results than an autoscleral free-flap graft. Its main advantages over donor graft material are availability and lower cost.

The communication of endogenous biomolecules (RNA, DNA, protein, hormone) via graft union might play key roles in the new traits formation of graft hybrids

International Nuclear Information System (INIS)

Khan, I.A.; Ghazal, L.; Arsalan, M.H.; Siddiqui, M.F.

2018-01-01

Plant graft hybridization is a fact of a sexual hybridization in which heritable changes trigger by grafting, it can produce hereditable variation types desired by breeders and can be used as a new method for germplasm innovation. This paper aimed to discuss new phenotypic variations such as phenotypic diversity and polyploidy formation discovered in recent years, new evidence supporting genetic material exchange between the rootstock and scion, and the timeliness, direction, and genetic stability of trait formation induced by graft hybridization. The unresolved mechanisms of trait variation were also discussed, and the relationship with exchange of chloroplast DNA (cpDNA) genetic information, horizontal gene transfer events of chloroplast and mitochondria, miRNA-mediated post-transcriptional regulation, and pressure-driven trait variations from graft hybridization were performed to clarify the relevant questions. Finally, the future research trend and key questions of graft hybridization were identified. Three clear conclusions for graft hybridization are presented: the new traits of graft hybrids have stable genetic characteristics and can be controlled via selection different genetic plant by grafting, and the products of graft hybrids were safer than those of transgenic plants. (author)

Radiation Grafted Polymer Membranes for Fuel Cell Applications

International Nuclear Information System (INIS)

Scherer, G.G.; Wallasch, F.; Ben Youcef, H.; Gubler, L.

2012-01-01

Partially fluorinated proton exchange membranes prepared via radiation induced graft copolymerization ('radiation grafting') offer the prospect of cost-effective and tailor made membrane electrolytes for the polymer electrolyte fuel cell (PEFC). The composition and structure of radiation grafted membranes can be adjusted in a broad range to balance the different requirements of proton transport and mechanical robustness. Based on the earlier work on Styrene grafting, the novel monomer combination α-methyl-styrene/methacrylonitrile (AMS/MAN) is introduced for improved stability in the prevailing fuel cell environment. Successful fuel cell experiments proved the concept. (author)

Radiation Grafted Polymer Membranes for Fuel Cell Applications

Energy Technology Data Exchange (ETDEWEB)

Scherer, G G; Wallasch, F; Ben Youcef, H; Gubler, L [Electrochemistry Laboratory, Paul Scherrer Institut, CH-5232 Villigen (Switzerland)

2012-09-15

Partially fluorinated proton exchange membranes prepared via radiation induced graft copolymerization ('radiation grafting') offer the prospect of cost-effective and tailor made membrane electrolytes for the polymer electrolyte fuel cell (PEFC). The composition and structure of radiation grafted membranes can be adjusted in a broad range to balance the different requirements of proton transport and mechanical robustness. Based on the earlier work on Styrene grafting, the novel monomer combination {alpha}-methyl-styrene/methacrylonitrile (AMS/MAN) is introduced for improved stability in the prevailing fuel cell environment. Successful fuel cell experiments proved the concept. (author)

Excellent Aesthetic and Functional Outcome After Fractionated Carbon Dioxide Laser Skin Graft Revision Surgery: Case Report and Review of Laser Skin Graft Revision Techniques.

Science.gov (United States)

Ho, Derek; Jagdeo, Jared

2015-11-01

Skin grafts are utilized in dermatology to reconstruct a defect secondary to surgery or trauma of the skin. Common indications for skin grafts include surgical removal of cutaneous malignancies, replacement of tissue after burns or lacerations, and hair transplantation in alopecia. Skin grafts may be cosmetically displeasing, functionally limiting, and significantly impact patient's quality-of-life. There is limited published data regarding skin graft revision to enhance aesthetics and function. Here, we present a case demonstrating excellent aesthetic and functional outcome after fractionated carbon dioxide (CO2) laser skin graft revision surgery and review of the medical literature on laser skin graft revision techniques.

Sustained Thromboresistant Bioactivity with Reduced Intimal Hyperplasia of Heparin-Bonded Polytetrafluoroethylene Propaten Graft in a Chronic Canine Femoral Artery Bypass Model.

Science.gov (United States)

Freeman, John; Chen, Aaron; Weinberg, Roy J; Okada, Tamuru; Chen, Changyi; Lin, Peter H

2018-05-01

Bypass graft thrombosis remains a significant mode of failure in prosthetic graft revascularization. The purpose of this investigation was to evaluate the long-term thromboresistant effect of heparin-bonded expanded polytetrafluoroethylene (ePTFE) graft using Carmeda BioActive Surface technology in a canine model. Bilateral femorofemoral artery bypass grafts with ePTFE grafts were performed in 25 adult grayhound dogs. In each animal, a heparin-bonded ePTFE graft (Propaten, WL Gore) was placed on one side, whereas a control nonheparin graft was placed on the contralateral side. The graft patency was assessed at 1, 6, 12, 18, and 24 months (n = 5 per group) following the bypass. Heparin bioactivity of the graft material was analyzed. The effect of intimal hyperplasia was also assessed. All bypass grafts were patent at 1 month. Significantly greater patency rates were noted in the Propaten group compared to the control group at 12, 18, and 24 months, which were 84%, 80%, and 80% vs. 55%, 35%, and 20%, respectively (P  0.05). Heparin-bonded ePTFE graft provides a thromboresistant surface and reduced anastomotic intimal hyperplasia at 2 years. The stable heparin bioactivity of the Propaten graft confers an advantage in long-term graft patency. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Revascularisation of fresh compared with demineralised bone grafts in rats

DEFF Research Database (Denmark)

Solheim, E; Pinholt, E M; Talsnes, O

2001-01-01

Revascularisation of bone grafts is influenced by both the anatomical origin and the pre-implantation processing of the graft. We investigated the revascularisation by entrapment of 141Ce (cerium)-labelled microspheres in large, fresh and demineralised syngeneic grafts of predominantly cancellous...... (iliac bone) or cortical (tibial diaphysis) bone three weeks after heterotopic implantation in rats. The mean (SD) 141Ce deposition index (counts per minute (cpm) of mg recovered implant/cpm of mg host iliac bone) was higher in fresh iliac bone grafts, 0.98 (0.46) compared to that of demineralised iliac...... bone, 0.32 (0.20), p bone grafts, 0.51 (0.27), p = 0.007. We found no significant difference in the mean 141Ce deposition index between fresh tibial bone grafts and demineralised tibial bone grafts, 0.35 (0.42), p = 0.4, or between demineralised tibial grafts and demineralised...

Fusion Rates of Different Anterior Grafts in Thoracolumbar Fractures.

Science.gov (United States)

Antoni, Maxime; Charles, Yann Philippe; Walter, Axel; Schuller, Sébastien; Steib, Jean-Paul

2015-11-01

Retrospective CT analysis of anterior fusion in thoracolumbar trauma. The aim of this study was to compare fusion rates of different bone grafts and to analyze risk factors for pseudarthrosis. Interbody fusion is indicated in anterior column defects. Different grafts are used: autologous iliac crest, titanium mesh cages filled with cancellous bone, and autologous ribs. It is not clear which graft offers the most reliable fusion. Radiologic data of 116 patients (71 men, 45 women) operated for type A2, A3, B, or C fractures were analyzed. The average age was 44.6 years (range, 16-75 y) and follow-up was 2.7 years (range, 1-9 y). All patients were treated by posterior instrumentation followed by an anterior graft: 53 cases with iliac crest, 43 cases with mesh cages, and 20 with rib grafts. Fusion was evaluated on CT and classified into complete fusion, partial fusion, unipolar pseudarthrosis, and bipolar pseudarthrosis. Iliac crest fused in 66%, cages in 98%, and rib grafts in 90%. The fusion rate of cages filled with bone was significantly higher as the iliac graft fusion rate (P=0.002). The same was applied to rib grafts compared with iliac crest (P=0.041). Additional bone formation around the main graft, bridging both vertebral bodies, was observed in 31 of the 53 iliac crests grafts. Pseudarthrosis occurred more often in smokers (P=0.042). A relationship between fracture or instrumentation types, sex, age, BMI, and fusion could not be determined. Tricortical iliac crest grafts showed an unexpected high pseudarthrosis rate in thoracolumbar injuries. Their cortical bone is dense and their fusion surface is small. Rib grafts led to a better fusion when used in combination with the cancellous bone from the fractured vertebral body. Titanium mesh cages filled with cancellous bone led to the highest fusion rate and built a complete bony bridge between vertebral bodies. Smoking seemed to influence fusion. Case control study, Level III.

Rootstock alleviates PEG-induced water stress in grafted pepper seedlings: physiological responses.

Science.gov (United States)

Penella, Consuelo; Nebauer, Sergio G; Bautista, Alberto San; López-Galarza, Salvador; Calatayud, Ángeles

2014-06-15

Recent studies have shown that tolerance to abiotic stress, including water stress, is improved by grafting. In a previous work, we took advantage of the natural variability of Capsicum spp. and selected accessions tolerant and sensitive to water stress as rootstocks. The behavior of commercial cultivar 'Verset' seedlings grafted onto the selected rootstocks at two levels of water stress provoked by adding 3.5 and 7% PEG (polyethylene glycol) was examined over 14 days. The objective was to identify the physiological traits responsible for the tolerance provided by the rootstock in order to determine if the tolerance is based on the maintenance of the water relations under water stress or through the activation of protective mechanisms. To achieve this goal, various physiological parameters were measured, including: water relations; proline accumulation; gas exchange; chlorophyll fluorescence; nitrate reductase activity; and antioxidant capacity. Our results indicate that the effect of water stress on the measured parameters depends on the duration and intensity of the stress level, as well as the rootstock used. Under control conditions (0% PEG) all plant combinations showed similar values for all measured parameters. In general terms, PEG provoked a strong decrease in the gas exchange parameters in the cultivar grafted onto the sensitive accessions, as also observed in the ungrafted plants. This effect was related to lower relative water content in the plants, provoked by an inefficient osmotic adjustment that was dependent on reduced proline accumulation. At the end of the experiment, chronic photoinhibition was observed in these plants. However, the plants grafted onto the tolerant rootstocks, despite the reduction in photosynthetic rate, maintained the protective capacity of the photosynthetic machinery mediated by osmotic adjustment (based on higher proline content). In addition, water stress limited uptake and further NO3(-) transfer to the leaves. Increased

The Effect of Platelet-Rich Plasma on Survival of the Composite Graft and the Proper Time of Injection in a Rabbit Ear Composite Graft Model

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Hyun Nam Choi

2014-11-01

Full Text Available BackgroundAdministration of growth factors has been associated with increased viability of composite grafts greater than 1-cm in diameter. Platelet-rich plasma (PRP contains many of the growth factors studied. In this study, we evaluate the effect of PRP injection on composite graft viability and the proper time for injection.MethodsA total of 24 New Zealand White rabbits were divided into four groups. Autologous PRP was injected into the recipient sites three days before grafting in group 1, on the day of grafting in group 2, and three days after grafting in group 3. Group 4 served as control without PRP administration. Auricular composite grafts of 3-cm diameter were harvested and grafted back into place after being rotated 180 degrees. Median graft viability and microvessel density were evaluated at day 21 of graft via macroscopic photographs and immunofluorescent staining, respectively.ResultsThe median graft survival rate was 97.8% in group 1, 69.2% in group 2, 55.7% in group 3, and 40.8% in the control group. The median vessel counts were 34 (per ×200 HPF in group 1, 24.5 in group 2, 19.5 in group 3, and 10.5 in the control group.ConclusionsThis study demonstrates that PRP administration is associated with increased composite graft viability. All experimental groups showed a significantly higher survival rate and microvessel density, compared with the control group. Pre-administration of PRP was followed by the highest graft survival rate and revascularization. PRP treatments are minimally invasive, fast, easily applicable, and inexpensive, and offer a potential clinical pathway to larger composite grafts.

Study by the positron annihilation technique of Graft copolimerization of methyl methacrylate in polyethylene induced by gamma radiation

International Nuclear Information System (INIS)

Zaldivar Gonzalez, M.E.

1992-01-01

Radiation initiated grafting is a very broad field which has attracted considerable interest over the last two decades. Graft copolymers may combine suitable properties of two polymeric components. Radiation methods are particulary appropiate for the production of a large variety of graft copolymers having interesting properties. Ionizing radiation has provided a convenient and clean method to activate a sustrate polymer and undoubtedly, it has added impetus to this field of research. In the present work, graft polymerization of methyl methacrylate (MMA) onto low density polyethylene (LDPE) was carried out. The effect of gamma ray irradiation dose on the grafting degree was investigated for two different methods: direct and preirradiation. The best method to prepare the copolymer for the LDPE film thickness studied: 0.05 and 0.2 mm., was direct method. In both polyethylene thickness, the grafting degree increased as a function of the reaction time. However, grafting for LDPE 0.2 mm. it is better, because the copolymer with that thickness conserve the main physical-chemistry properties of the LDPE along the different grafting degrees obtained, which it is important for practical purposes. Infrared spectroscopy was used to probe the changes ocurred in the LDPE structure with the graft of MMA, first spectrum showed typical bands for LDPE structure, while in the second spectrum new bands appeared which corresponded to PMMA structure grafted onto LDPE. Positron annihilation lifetime technique was applied to study the copolymer microstructure according to increase of grafting degree. O-PS lifetime and intensity tend to decrease. This behavior could be due to the diminution of free volume in the original LDPE matrix as grafting proceeds. Copolymer morphology was observed using optical microscopy (Author)

Grafting of acrylamide onto synthetic co polyamide by gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Hamoud, M R; Qamhieyh, E A [Chemistry Dept., College of Ibn Al-Haitham Baghdad university-Adhamiyah-Baghdad- (Iraq)

1995-10-01

Grafted copolymer was prepared by using gamma irradiation to graft acrylamide onto polymeric molecule prepared by interfacial condensation between two diamine molecules like 1,2 diamino propane and 1,6 diamino-hexane in aqueous layer with sebacoyl chloride in organic layer. The resulted co polyamide was grafted with acrylamide using gamma irradiation. The optimum conditions of grafting reaction were found, also various factors such as the effect of solvents, redox systems and the role water on the radiochemical grafting were studied. Many techniques were used in the characterization of the copolymer before and after grafting. 8 figs.,.

An Introduction to the Septal Extension Graft

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Myung-Hoon Kim

2014-01-01

Full Text Available The septal extension graft is a very useful method of controlling nasal lengthening and tip projection, rotation, and shape by fixing a graft to the septum, which leads to a strong supporting structure. Enhancing graft stability is important for better long-term outcomes and minimizing complications or relapse, and even more efficient application of these methods is needed for East Asians who lack enough cartilage to be harvested in addition to possessing a weak cartilage framework. In this paper, the methods for overcoming the drawbacks of the septal extension graft, such as instability, a fixed tip, and insufficiency of cartilage, are presented, and the applications of each method for greater satisfaction with surgical outcomes are also discussed.

Oxidation of Phenol by Hydrogen Peroxide Catalyzed by Metal-Containing Poly(amidoxime Grafted Starch

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Hany El-Hamshary

2011-11-01

Full Text Available Polyamidoxime chelating resin was obtained from polyacrylonitrile (PAN grafted starch. The nitrile groups of the starch-grafted polyacrylonitrile (St-g-PAN were converted into amidoximes by reaction with hydroxylamine under basic conditions. The synthesized graft copolymer and polyamidoxime were characterized by FTIR, TGA and elemental microanalysis. Metal chelation of the polyamidoxime resin with iron, copper and zinc has been studied. The produced metal-polyamidoxime polymer complexes were used as catalysts for the oxidation of phenol using H2O2 as oxidizing agent. The oxidation of phenol depends on the central metal ion present in the polyamidoxime complex. Reuse of M-polyamidoxime catalyst/H2O2 system showed a slight decrease in catalytic activities for all M-polyamidoxime catalysts.

Grafted SiC nanocrystals

DEFF Research Database (Denmark)

Saini, Isha; Sharma, Annu; Dhiman, Rajnish

2017-01-01

), raman spectroscopy and X-ray diffraction (XRD) measurements. UV–Visible absorption spectroscopy was used to study optical properties such as optical energy gap (Eg), Urbach's energy (Eu), refractive index (n), real (ε1) and imaginary (ε2) parts of dielectric constant of PVA as well as PVA......Polyvinyl alcohol (PVA) grafted SiC (PVA-g-SiC)/PVA nanocomposite was synthesized by incorporating PVA grafted silicon carbide (SiC) nanocrystals inside PVA matrix. In-depth structural characterization of resulting nanocomposite was carried out using fourier transform infrared spectroscopy (FTIR...

Evaluation of coronary artery bypass grafts with magnetic resonance imaging

International Nuclear Information System (INIS)

Okamura, Yoshitaka; Yamada, Yasuyuki; Mochizuki, Yoshihiko; Iida, Hiroshi; Mori, Hideaki; Sugita, You-ichi; Shimada, Kou-ichirou

1997-01-01

Currently, the efficacy of magnetic resonance imaging (MRI) for evaluating coronary artery disease has been reported. In this study, we have evaluated the usefulness and the problems of MRI for evaluating the patency of coronary artery bypass grafts. Thirty-five patients who received coronary artery bypass grafting (CABG) were evaluated by using MRI for determining the graft patency compared with conventional coronary angiography. There were 30 men and 5 women. The mean age was 61.2 years (range 45 to 75). The 35 patients had a total of 92 grafts (28 internal thoracic artery, 7 gastroepiploic artery and 57 saphenous vein grafts). Magnetic resonance coronary angiogram (MRCA) was performed with SIGNA HORIZON 1.5 T (GE Inc.) by using 2D-FASTCARD sequence. All patients underwent imaging in the transverse and coronal planes, most had imaging in the sagittal plane, and a few had in the oblique plane. By using MRCA, 82 of 90 grafts were diagnosed correctly as patent, and 1 of 2 grafts were diagnosed correctly as occluded. Thirty-four of 40 LAD grafts (85%), 20 of 22 RCA grafts (91%) and 29 of 30 Cx grafts (97%) were correctly evaluated. The efficacy of MRCA for evaluating the patency of coronary artery bypass grafts was recognized. But the sternal wire (stainless steel) and hemoclip interfere with the interpretation and reduce the sensitivity. Higher sensitivity may be obtained by changing the material of the sternal wires and hemoclips at coronary surgery. (author)

Industrial application of electron beams for grafting and vulcanization

Energy Technology Data Exchange (ETDEWEB)

Makuuchi, Keizo [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

1994-12-31

The topics discussed are radiation graft polymerization; industrial application of radiation grafting - ion exchange membrane for a battery separator, ammonia adsorbent, non-flammable PE (polyethylene) foam; R and D on radiation grafting, radiation vulcanization of natural rubber.

Industrial application of electron beams for grafting and vulcanization

International Nuclear Information System (INIS)

Keizo Makuuchi

1994-01-01

The topics discussed are radiation graft polymerization; industrial application of radiation grafting - ion exchange membrane for a battery separator, ammonia adsorbent, non-flammable PE (polyethylene) foam; R and D on radiation grafting, radiation vulcanization of natural rubber

Assessment of Novel Anti-thrombotic Fusion Proteins for Inhibition of Stenosis in a Porcine Model of Arteriovenous Graft.

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Christi M Terry

Full Text Available Hemodialysis arteriovenous synthetic grafts (AVG provide high volumetric blood flow rates shortly after surgical placement. However, stenosis often develops at the vein-graft anastomosis contributing to thrombosis and early graft failure. Two novel fusion proteins, ANV-6L15 and TAP-ANV, inhibit the tissue factor/factor VIIa coagulation complex and the factor Xa/factor Va complex, respectively. Each inhibitor domain is fused to an annexin V domain that targets the inhibitor activity to sites of vascular injury to locally inhibit thrombosis. This study's objective was to determine if these antithrombotic proteins are safe and effective in inhibiting AVG stenosis.A bolus of either TAP-ANV or ANV-6L15 fusion protein was administered intravenously immediately prior to surgical placement of a synthetic graft between the external jugular vein and common carotid artery in a porcine model. At surgery, the vein and artery were irrigated with the anti-thrombotic fusion protein. Control animals received intravenous heparin. At 4 weeks, MRI was performed to evaluate graft patency, the pigs were then euthanized and grafts and attached vessels were explanted for histomorphometric assessment of neointimal hyperplasia at the vein-graft anastomosis. Blood was collected at surgery, immediately after surgery and at euthanasia for serum metabolic panels and coagulation chemistries.No acute thrombosis occurred in the control group or in either experimental group. No abnormal serum chemistries, activated clotting times or PT, PTT values were observed after treatment in experimental or control animals. However, at the vein-graft anastomosis, there was no difference between the control and experimental groups in cross-sectional lumen areas, as measured on MRI, and no difference in hyperplasia areas as determined by histomorphometry. These results suggest that local irrigation of TAP-ANV or ANV-6L15 intra-operatively was as effective in inhibiting acute graft thrombosis

[Skin graft, smoking and diabetes mellitus type 2].

Science.gov (United States)

Pérez-Guisado, Joaquín; Fidalgo-Rodríguez, Félix T; Gaston, Kate L; Rioja, Luis F; Thomas, Steven J

2012-01-01

Smoking and hyperglycemia decrease the success of skin graft survival in specific circumstances. It is well known that smoking and diabetes mellitus (DM) type 2 increase the oxidative and impair the endothelial function. The objective of this retrospective study was to determine if smoking and DM type 2 are factors associated with lower skin graft survival, in different etiologies of the injury associated to the skin loss. It was a bicentric, retrospective, cross sectional case control study, carried out on 2457 medical patients who met the inclusion criteria. It was carried out over a 10 years period between January 2000-December 2009, at Reina Sofía University Hospital (Córdoba, Spain) and UAB Hospital at Birmingham (Alabama, USA). The percentage of successful graft for each group and its control were analyzed by Chi-square test. The confidence interval chosen for statistical differences was 95%. Smoking and DM type 2 decreased the percentage of skin graft survival when compared with their control groups. DM type 2 was associated with greater negative success on skin graft survival than smoking when compared with their control groups. There was a statistically significant drop in skin graft of 18% in smoking group (range: 68-86%) and 25% in DM type 2 group (53-78%). The OR showed a clear association between the risk factors studied and the lower skin graft success, being stronger for DM type 2. In conclusion, DM type 2 and smoking are factors associated to lower skin graft take.

Efficient fabrication of high-capacity immobilized metal ion affinity chromatographic media: The role of the dextran-grafting process and its manipulation.

Science.gov (United States)

Zhao, Lan; Zhang, Jingfei; Huang, Yongdong; Li, Qiang; Zhang, Rongyue; Zhu, Kai; Suo, Jia; Su, Zhiguo; Zhang, Zhigang; Ma, Guanghui

2016-03-01

Novel high-capacity Ni(2+) immobilized metal ion affinity chromatographic media were prepared through the dextran-grafting process. Dextran was grafted to an allyl-activated agarose-based matrix followed by functionalization for the immobilized metal ion affinity chromatographic media. With elaborate regulation of the allylation degree, dextran was completely or partly grafted to agarose microspheres, namely, completely dextran-grafted agarose microspheres and partly dextran-grafted ones, respectively. Confocal laser scanning microscope results demonstrated that a good adjustment of dextran-grafting degree was achieved, and dextran was distributed uniformly in whole completely dextran-grafted microspheres, while just distributed around the outside of the partly dextran-grafted ones. Flow hydrodynamic properties were improved greatly after the dextran-grafting process, and the flow velocity increased by about 30% compared with that of a commercial chromatographic medium (Ni Sepharose FF). A significant improvement of protein binding performance was also achieved by the dextran-grafting process, and partly dextran-grafted Ni(2+) chelating medium had a maximum binding capacity for His-tagged lactate dehydrogenase about 2.5 times higher than that of Ni Sepharose FF. The results indicated that this novel chromatographic medium is promising for applications in high-efficiency and large-scale protein purification. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Grafting improves cucumber water stress tolerance in Saudi Arabia

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Abdulaziz R. Al-Harbi

2018-02-01

Full Text Available Water scarcity is a major limiting factor for crop productivity in arid and semi-arid areas. Grafting elite commercial cultivars onto selected vigorous rootstocks is considered as a useful strategy to alleviate the impact of environmental stresses. This study aims to investigate the feasibility of using grafting to improve fruit yield and quality of cucumber under water stress conditions. Alosama F1 cucumber cultivar (Cucumis sativus L. was grafted onto Affyne (Cucumis sativus L. and Shintoza A90 (Cucurbitamaxima × C. moschata rootstocks. Non-grafted plants were used as control. All genotypes were grown under three surface drip irrigation regimes: 50%, 75% and 100% of the crop evapotranspiration (ETc, which represent high-water stress, moderate-water stress and non-water stress conditions, respectively. Yield and fruit quality traits were analyzed and assessed. In comparison to the non-grafted plants, the best grafting treatment under water stress was Alosama F1 grafted onto Shintoza A90 rootstock. It had an overall improved yield and fruit quality under water stress owing to an increase in the total fruit yield by 27%, from 4.815 kg plant−1 in non-grafted treatment to 6.149 kg plant−1 in grafted treatment under moderate -water stress, total soluble solid contents (13%, titratable acidity (39% and vitamin C (33%. The soil water contents were low in soil surface and increase gradually with soil depth, while salt distribution showed an adverse trend. The positive effects of grafting on plant growth, productivity, and water use efficiency support this strategy as an useful tool for improving water stress tolerance in greenhouse grown cucumber in Saudi Arabia.

Bacterial adherence to vascular grafts after in vitro bacteremia

International Nuclear Information System (INIS)

Rosenman, J.E.; Pearce, W.H.; Kempczinski, R.F.

1985-01-01

All currently used arterial prosthetics have a greater susceptibility to infection following bacteremia than does autogenous tissue. This experiment compares quantitative bacterial adherence to various prosthetic materials after bacteremia carried out in a tightly controlled and quantitative fashion. Ten centimeters long, 4 mm i.d. Dacron, umbilical vein (HUV), and polytetrafluoroethylene (PTFE) grafts, as well as PTFE grafts with a running suture line at the midportion were tested. Each graft was interposed into a pulsatile perfusion system modified from a Waters MOX 100 TM renal transplant pump. Indium-111-labeled Staphylococcus aureus were added to heparinized canine blood to give a mean concentration of 4.7 X 10(6) bacteria/cc. This infected blood was recirculated through each graft for 30 min at a rate of 125 cc/m, 100 Torr (sys), 60 beats/min. The gamma counts/graft were used to calculate the number of bacteria/cm2 of graft surface. After nine experiments, a mean of 9.63 X 10(5) bacteria/cm2 were adherent to the Dacron, 1.04 X 10(5) bacteria/cm2 to the HUV, and 2.15 X 10(4) bacteria/cm2 to the PTFE. These differences were all significant at the 0.05 level. The addition of a suture line increased bacterial adherence to the PTFE graft by 50%. These results suggest that PTFE is the vascular graft material of choice when a prosthetic graft must be implanted despite a high risk of subsequent clinical bacteremia. An in vitro, pulsatile perfusion model gave accurate and reproducible results, and appears well suited for further studies of bacterial, or platelet adherence to grafts, as well as the biomechanics of vascular conduits

Grafting improves cucumber water stress tolerance in Saudi Arabia.

Science.gov (United States)

Al-Harbi, Abdulaziz R; Al-Omran, Abdulrasoul M; Alharbi, Khadiga

2018-02-01

Water scarcity is a major limiting factor for crop productivity in arid and semi-arid areas. Grafting elite commercial cultivars onto selected vigorous rootstocks is considered as a useful strategy to alleviate the impact of environmental stresses. This study aims to investigate the feasibility of using grafting to improve fruit yield and quality of cucumber under water stress conditions. Alosama F 1 cucumber cultivar ( Cucumis sativus L.) was grafted onto Affyne ( Cucumis sativus L.) and Shintoza A90 ( Cucurbitamaxima × C. moschata ) rootstocks. Non-grafted plants were used as control. All genotypes were grown under three surface drip irrigation regimes: 50%, 75% and 100% of the crop evapotranspiration (ETc), which represent high-water stress, moderate-water stress and non-water stress conditions, respectively. Yield and fruit quality traits were analyzed and assessed. In comparison to the non-grafted plants, the best grafting treatment under water stress was Alosama F 1 grafted onto Shintoza A90 rootstock. It had an overall improved yield and fruit quality under water stress owing to an increase in the total fruit yield by 27%, from 4.815 kg plant -1 in non-grafted treatment to 6.149 kg plant -1 in grafted treatment under moderate -water stress, total soluble solid contents (13%), titratable acidity (39%) and vitamin C (33%). The soil water contents were low in soil surface and increase gradually with soil depth, while salt distribution showed an adverse trend. The positive effects of grafting on plant growth, productivity, and water use efficiency support this strategy as an useful tool for improving water stress tolerance in greenhouse grown cucumber in Saudi Arabia.

Crystallization of calcium carbonate on radiation-grafted polyethylene films

International Nuclear Information System (INIS)

Hou Zhengchi; Zhang Fengying; Deng Bo; Yang Haijun; Chen Shuang; Sheng Kanglong

2006-01-01

In biomineralization processes, nucleation and growth of inorganic crystals can be regulated by organic template molecules. This has inspired great interest in studying mimic biomineralization. In our study, growing CaCO 3 crystals on PE films functionalized through radiation-induced grafting was attempted. PE films grafted with different functional groups of different distributions and densities were used as substrates for CaCO 3 nucleation and crystal growth from Ca(HCO 3 ) 2 supersaturated solution under different environmental conditions (e.g. additives and temperature) to study the effects and mechanisms. The grafted PE films were analyzed by ATR-FTIR and AFM, and the evolution of CaCO 3 crystal formation on the grafted PE film was characterized by SEM, FTIR, and XRD. The results indicated that heterogeneous nucleation of CaCO 3 crystals was significantly facilitated by the functional groups grafted on the surface of PE films, that the morphology of CaCO 3 crystals could be controlled by distribution and density of the grafted functional groups, and that polymorphism of CaCO 3 crystal could be regulated by selection of grafting functional groups. We believe that studying the effects of chemical structures on inorganic crystallization is of great importance since radiation-induced grafting is an effective method to graft desirable functional groups onto different polymers by selected monomers, in the endeavor of developing advanced organic/inorganic composites with high performance, with a wide availability of polymers, monomers and inorganic solutions. (authors)

Rapid synthesis of graft copolymers from natural cellulose fibers.

Science.gov (United States)

Thakur, Vijay Kumar; Thakur, Manju Kumari; Gupta, Raju Kumar

2013-10-15

Cellulose is the most abundant natural polysaccharide polymer, which is used as such or its derivatives in a number of advanced applications, such as in paper, packaging, biosorption, and biomedical. In present communication, in an effort to develop a proficient way to rapidly synthesize poly(methyl acrylate)-graft-cellulose (PMA-g-cellulose) copolymers, rapid graft copolymerization synthesis was carried out under microwave conditions using ferrous ammonium sulfate-potassium per sulfate (FAS-KPS) as redox initiator. Different reaction parameters such as microwave radiation power, ratio of monomer, solvent and initiator concentrations were optimized to get the highest percentage of grafting. Grafting percentage was found to increase with increase in microwave power up to 70%, and maximum 36.73% grafting was obtained after optimization of all parameters. Fourier transforms infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA/DTA/DTG) analysis were used to confirm the graft copolymerization of poly(methyl acrylate) (PMA) onto the mercerized cellulose. The grafted cellulosic polymers were subsequently subjected to the evaluation of different physico-chemical properties in order to access their application in everyday life, in a direction toward green environment. The grafted copolymers demonstrated increased chemical resistance, and higher thermal stability. Published by Elsevier Ltd.

The impact of slow graft function on graft outcome is comparable to delayed graft function in deceased donor kidney transplantation.

Science.gov (United States)

Shin, Jung-Ho; Koo, Eun Hee; Ha, Sung Hae; Park, Ji Hyeon; Jang, Hye Ryoun; Lee, Jung Eun; Park, Jae-Berm; Kim, Sung Joo; Jung, Sin-Ho; Kim, Yoon-Goo; Kim, Dae Joong; Oh, Ha Young; Huh, Wooseong

2016-03-01

Slow graft function (SGF) can influence overall prognosis in patients receiving deceased donor kidney transplantation (DKT). However, the impact of SGF on renal function remains uncertain. We investigated retrospectively renal function in cases with SGF compared with early graft function (EGF) and delayed graft function (DGF). Renal function after transplantation was analyzed in 199 patients who underwent DKT. Patients were classified into 130 (65.3 %) cases with EGF, 27 (13.6 %) cases with SGF, 6 (3.0 %) cases with DGF and one dialysis (DGF1), and 36 (18.1 %) cases with DGF and two or more dialyses (DGF2). The 1-year estimated glomerular filtration rate (eGFR) in the SGF group was lower than that in the EGF group (P = 0.027), but the rate of eGFR decline did not differ between the groups. The risk factors for renal function were evaluated using the area under the eGFR curve over 3 years (AUCeGFR). Donor age was negatively, and recipient age and the number of HLA matches were positively correlated with the AUCeGFR (all P DKT. Moreover, it was comparable to DGF. Efforts should be dedicated to minimizing the development of SGF and DGF.

Fluorescence spectroscopy for assessment of liver transplantation grafts concerning graft viability and patient survival

Science.gov (United States)

Vollet Filho, José D.; da Silveira, Marina R.; Castro-e-Silva, Orlando; Bagnato, Vanderlei S.; Kurachi, Cristina

2015-06-01

Evaluating transplantation grafts at harvest is essential for its success. Laser-induced fluorescence spectroscopy (LIFS) can help monitoring changes in metabolic/structural conditions of tissue during transplantation. The aim of the present study is to correlate LIFSobtained spectra of human hepatic grafts during liver transplantation with post-operative patients' mortality rate and biochemical parameters, establishing a method to exclude nonviable grafts before implantation. Orthotopic liver transplantation, piggyback technique was performed in 15 patients. LIFS was performed under 408nm excitation. Collection was performed immediately after opening donor's abdominal cavity, after cold perfusion, end of back-table period, and 5 min and 1 h after warm perfusion at recipient. Fluorescence information was compared to lactate, creatinine, bilirubin and INR levels and to survival status. LIFS was sensitive to liver changes during transplantation stages. Study-in-progress; initial results indicate correlation between fluorescence and life/death status of patients.

Off-pump Coronary Artery Bypass Graft in a High Risk Patient ...

African Journals Online (AJOL)

On-pump coronary artery bypass graft (CABG) entails the use of cardiopulmonary bypass (CPB). The procedure is safe but it's not without complications like neurocognitive deficits, cerebrovascular accidents, myocardial ischemic injury and activation of inflammatory pathways that contribute to pulmonary, renal, hematologic ...

Study on radiation grafting reaction of MMA onto hydroxyapatite

International Nuclear Information System (INIS)

Jiang Bo

1996-01-01

The grafting reaction of MMA onto hydroxyapatite has been studied with the pre-irradiation method in air. The effects of radiation dose, monomer concentration, reaction temperature and inorganic acid on the system are observed. The grafting copolymerization is found to be controlled by the kinetics. If proper kinetic conditions are selected, a better grafting yield can be obtained. Employing weight method, burning method as well as SeM and IR analysis, it has been proved that MMA is definitely grafted onto hydroxyapatite by chemical bonds, which shows that it is possible to improve the interface of inorganic-organic composite materials and to make bioactive ceramics by using radiation induced-grafting copolymerization

Manipulation of the hypocotyl sink activity by reciprocal grafting of two Raphanus sativus varieties: its effects on morphological and physiological traits of source leaves and whole-plant growth.

Science.gov (United States)

Sugiura, Daisuke; Betsuyaku, Eriko; Terashima, Ichiro

2015-12-01

To reveal whether hypocotyl sink activities are regulated by the aboveground parts, and whether physiology and morphology of source leaves are affected by the hypocotyl sink activities, we conducted grafting experiments using two Raphanus sativus varieties with different hypocotyl sink activities. Comet (C) and Leafy (L) varieties with high and low hypocotyl sink activities were reciprocally grafted and resultant plants were called by their scion and stock such as CC, LC, CL and LL. Growth, leaf mass per area (LMA), total non-structural carbohydrates (TNCs) and photosynthetic characteristics were compared among them. Comet hypocotyls in CC and LC grew well regardless of the scions, whereas Leafy hypocotyls in CL and LL did not. Relative growth rate was highest in LL and lowest in CC. Photosynthetic capacity was correlated with Rubisco (ribulose 1·5-bisphosphate carboxylase/oxygenase) content but unaffected by TNC. High C/N ratio and accumulation of TNC led to high LMA and structural LMA. These results showed that the hypocotyl sink activity was autonomously regulated by hypocotyl and that the down-regulation of photosynthesis was not induced by TNC. We conclude that the change in the sink activity alters whole-plant growth through the changes in both biomass allocation and leaf morphological characteristics in R. sativus. © 2015 John Wiley & Sons Ltd.

Radiation-Induced Graft Polymerization: Gamma Radiation and Electron Beam Technology for Materials Development

International Nuclear Information System (INIS)

Madrid, Jordan F.; Cabalar, Patrick Jay; Lopez, Girlie Eunice; Abad, Lucille V.

2015-01-01

The formation of functional hybrid materials by attaching polymer chains with advantageous tailored properties to the surface of a base polymer with desirable bulk character is an attractive application of graft copolymerization. Radiation-induced graft polymerization (RIGP) has been a popular approach for surface modification of polymers because of its merits over conventional chemical processes. RIGP, which proceeds primarily via free radical polymerization process, has the advantages such as simplicity, low cost, control over process and adjustment of the materials composition and structure. RIGP can be performed using either electron beam or gamma radiation and it can be applied to both synthetic and natural polymers. These merits make RIGP a popular research topic worldwide. Moreover, the materials synthesized and produced via RIGP has found applications, and were proposed to produce continuous impact, in the fields of medicine, agriculture, pollution remediation, rare earth and valuable metals recovery, fuel cell membrane synthesis and catalysis to name a few. From 2012 our group has performed electron beam and gamma radiation-induced graft polymerization of various monomers onto polymers of natural and synthetic origins (e.g. monomers - glycidyl methacrylate, styrene, acrylonitrile, N,N-dimethylaminoethyl methacrylate; base polymers – polyethylene/polypropylene nonwoven fabric, polypropylene nonwoven fabric pineapple fibers, cellulose nonwoven fabric microcrystalline cellulose). We tested these grafted materials for heavy metals (Pb, Ni, Cu) and organic molecule removal from aqueous solutions and E. coli activity (using reversible addition fragmentation chain transfer RAFT mediated grafting). The results clearly showed the success of materials modified via FIGP in these applications. Currently, we are studying the applications of grafted materials on treatment of waste waters from tanning industry, value addition to abaca nonwoven fabrics cell sheet

Molecular Dynamics Simulations of Silica Nanoparticles Grafted with Poly(ethylene oxide) Oligomer Chains

KAUST Repository

Hong, Bingbing

2012-03-01

A molecular model of silica nanoparticles grafted with poly(ethylene oxide) oligomers has been developed for predicting the transport properties of nanoparticle organic-hybrid materials (NOHMs). Ungrafted silica nanoparticles in a medium of poly(ethylene oxide) oligomers were also simulated to clarify the effect of grafting on the dynamics of nanoparticles and chains. The model approximates nanoparticles as solid spheres and uses a united-atom representation for chains, including torsional and bond-bending interactions. The calculated viscosities from Green-Kubo relationships and temperature extrapolation are of the same order of magnitude as experimental data but show a smaller activation energy relative to real NOHMs systems. Grafted systems have higher viscosities, smaller diffusion coefficients, and slower chain dynamics than the ungrafted ones at high temperatures. At lower temperatures, grafted systems exhibit faster dynamics for both nanoparticles and chains relative to ungrafted systems, because of lower aggregation of particles and enhanced correlations between nanoparticles and chains. This agrees with the experimental observation that NOHMs have liquidlike behavior in the absence of a solvent. For both grafted and ungrafted systems at low temperatures, increasing chain length reduces the volume fraction of nanoparticles and accelerates the dynamics. However, at high temperatures, longer chains slow down nanoparticle diffusion. From the Stokes-Einstein relationship, it was determined that the coarse-grained treatment of nanoparticles leads to slip on the nanoparticle surfaces. Grafted systems obey the Stokes-Einstein relationship over the temperature range simulated, but ungrafted systems display deviations from it. © 2012 American Chemical Society.

A novel fibrin gel derived from hyaluronic acid-grafted fibrinogen

Energy Technology Data Exchange (ETDEWEB)

Yang, Chiung L; Chen, Hui W; Wang, Tzu C; Wang, Yng J, E-mail: wang@ym.edu.tw [Institute of Biomedical Engineering, National Yang Ming University, No. 155, Sec. 2, Li-Nung St., Shih-Pai, Taipei, Taiwan 112 (China)

2011-04-15

Fibrinogen is a major plasma protein that forms a three-dimensional fibrin gel upon being activated by thrombin. In this study, we report the synthesis and potential applications of hybrid molecules composed of fibrinogen coupled to the reducing ends of short-chain hyaluronic acids (sHAs) by reductive amination. The grafting of sHAs to fibrinogen was verified by analyzing particle size, zeta potential and gel-electrophoretic mobility of the hybrid molecules. The sHA-fibrinogen hybrid molecules with graft ratios (sHA/fibrinogen) of up to 6.5 retained the ability to form gels in response to thrombin activation. The sHA-fibrin gels were transparent in appearance and exhibited high water content, which were characteristics distinct from those of gels formed by mixtures of sHAs and fibrinogen. The potential applications of the sHA-fibrin gels were evaluated. The sHA-fibrinogen gel with a graft ratio of 3.6 (S3.6F) was examined for its ability to encapsulate and support the differentiation of ATDC5 chondrocyte-like cells. Compared with the fibrinogen-formed gel, cells cultured in the S3.6F gel exhibited increased lacunae formation; moreover, the abundance of cartilaginous extracellular matrix molecules and the expression of chondrocyte marker genes, such as aggrecan, collagen II and Sox9, were also significantly increased. Our data suggest that the three-dimensional gel formed by the sHA-fibrinogen hybrid is a better support than the fibrin gel for chondrogenesis induction.

A novel fibrin gel derived from hyaluronic acid-grafted fibrinogen

International Nuclear Information System (INIS)

Yang, Chiung L; Chen, Hui W; Wang, Tzu C; Wang, Yng J

2011-01-01

Fibrinogen is a major plasma protein that forms a three-dimensional fibrin gel upon being activated by thrombin. In this study, we report the synthesis and potential applications of hybrid molecules composed of fibrinogen coupled to the reducing ends of short-chain hyaluronic acids (sHAs) by reductive amination. The grafting of sHAs to fibrinogen was verified by analyzing particle size, zeta potential and gel-electrophoretic mobility of the hybrid molecules. The sHA-fibrinogen hybrid molecules with graft ratios (sHA/fibrinogen) of up to 6.5 retained the ability to form gels in response to thrombin activation. The sHA-fibrin gels were transparent in appearance and exhibited high water content, which were characteristics distinct from those of gels formed by mixtures of sHAs and fibrinogen. The potential applications of the sHA-fibrin gels were evaluated. The sHA-fibrinogen gel with a graft ratio of 3.6 (S3.6F) was examined for its ability to encapsulate and support the differentiation of ATDC5 chondrocyte-like cells. Compared with the fibrinogen-formed gel, cells cultured in the S3.6F gel exhibited increased lacunae formation; moreover, the abundance of cartilaginous extracellular matrix molecules and the expression of chondrocyte marker genes, such as aggrecan, collagen II and Sox9, were also significantly increased. Our data suggest that the three-dimensional gel formed by the sHA-fibrinogen hybrid is a better support than the fibrin gel for chondrogenesis induction.

Five-year outcomes following a randomized trial of femorofemoral and femoropopliteal bypass grafting with heparin-bonded or standard polytetrafluoroethylene grafts

DEFF Research Database (Denmark)

Lindholt, Jes S.; Houlind, K.; Gottschalksen, B

2016-01-01

BACKGROUND: Cohort studies suggest superior long-term patency of luminal heparin-bonded polytetrafluoroethylene (Hb-PTFE) bypass grafts compared with standard PTFE grafts. The aim of this study was to compare the outcomes of Hb-PTFE grafts with those of standard PTFE grafts 5 years after...... a randomized trial. METHODS: Patients with intermittent claudication or critical limb ischaemia requiring femorofemoral or femoropopliteal bypass grafting were randomized in a clinical trial of Hb-PTFE versus standard PTFE in 11 Scandinavian centres between 2005 and 2009. Patients were followed up for 5 years...... of the primary outcome. Use of Hb-PTFE significantly improved patency by 37 per cent at 2 years, but 5 years after randomization there was no difference in primary patency (adjusted hazard ratio (HR) 0·95, 95 per cent c.i. 0·71 to 1·28; P = 0·748). In patients with critical limb ischaemia the use of Hb-PTFE...

A Tat-grafted anti-nucleic acid antibody acquires nuclear-localization property and a preference for TAR RNA

International Nuclear Information System (INIS)

Jeong, Jong-Geun; Kim, Dong-Sik; Kim, Yong-Sung; Kwon, Myung-Hee

2011-01-01

Highlights: → We generate ' H3 Tat-3D8' by grafting Tat 48-60 peptide to VH CDR of 3D8 scFv antibody. → H3 Tat-3D8 antibody retains nucleic acid binding and hydrolyzing activities. → H3 Tat-3D8 acquires a preference for TAR RNA structure. → Properties of Tat 48-60 is transferred to an antibody via Tat-grafting into a CDR. -- Abstract: The 3D8 single chain variable fragment (3D8 scFv) is an anti-nucleic acid antibody that can hydrolyze nucleic acids and enter the cytosol of cells without reaching the nucleus. The Tat peptide, derived from the basic region of the HIV-1 Tat protein, translocates to cell nuclei and has TAR RNA binding activity. In this study, we generated a Tat-grafted antibody ( H3 Tat-3D8) by replacing complementarity-determining region 3 (CDR3) within the VH domain of the 3D8 scFv with a Tat 48-60 peptide (GRKKRRQRRRPPQ). H3 Tat-3D8 retained the DNA-binding and DNA-hydrolyzing activity of the scFv, and translocated to the nuclei of HeLa cells and preferentially recognized TAR RNA. Thus, the properties associated with the Tat peptide were transferred to the antibody via Tat-grafting without loss of the intrinsic DNA-binding and hydrolyzing activities of the 3D8 scFv antibody.

Quantitative [18F]fluorodopa/PET and histology of fetal mesencephalic dopaminergic grafts to the striatum of MPTP-poisoned minipigs

DEFF Research Database (Denmark)

Dall, Annette Møller; Danielsen, Erik Hvid; Sørensen, Jens Christian

2002-01-01

-expressing HiB5 cells, a rat-derived neural cell line, tended to impair the survival of the grafts with the lowest values for graft volumes, TH-positive cell numbers, behavioral scores, and relative DOPA decarboxylase activity. From the results we conclude that pig ventral mesencephalic allografts can restore...

Radiation-induced grafting of acrylic acid onto polypropylene film and its biodegradability

Science.gov (United States)

Mandal, Dev K.; Bhunia, Haripada; Bajpai, Pramod K.; Chaudhari, C. V.; Dubey, K. A.; Varshney, L.

2016-06-01

Polypropylene based commodity polyolefins are widely used in packaging, manufacturing, electrical, pharmaceutical and other applications. The aim of the present work is to study the effect of grafting of acrylic acid on the biodegradability of acrylic acid grafted polypropylene. The effect of different conditions showed that grafting percentage increased with increase in monomer concentration, radiation dose and inhibitor concentration but decreased with increase in radiation dose rate. The maximum grafting of 159.4% could be achieved at optimum conditions. The structure of grafted polypropylene films at different degree of grafting was characterized by EDS, FTIR, TGA, DSC, SEM and XRD. EDS studies showed that the increase in acrylic acid grafting percentage increased the hydrophilicity of the grafted films. FTIR studies indicated the presence of acrylic acid on the surface of polypropylene film. TGA studies revealed that thermal stability decreased with increase in grafting percentage. DSC studies showed that melting temperature and crystallinity of the grafted polypropylene films lower than polypropylene film. SEM studies indicated that increase in acrylic acid grafting percentage increased the wrinkles in the grafted films. The maximum biodegradability could be achieved to 6.85% for 90.5% grafting. This suggested that microorganisms present in the compost could biodegrade acrylic acid grafted polypropylene.

Evaluation of aortocoronary bypass graft patency by reconstructed CT image

International Nuclear Information System (INIS)

Kawakita, Seizaburo; Koide, Takashi; Saito, Yoshio; Yamamoto, Tadao; Iwasaki, Tadaaki

1982-01-01

Ten patients were examined in the period of three months from January to March 1981. The patients were operated from 1 month to 7 years before CT. A bypass to the left anterior descending artery (LAD) was grafted in 10 cases, 2 to the right coronary artery (RCA), 4 to an obtuse marginal artery (OM), and 1 to a diagonal artery. Image reconstruction was performed in 10 cases by using an image analytical computer Evaluskop. Appropriate planes for reconstruction were selected by trial and error methods upon observation of CT images. When gained picture of a graft course coincided with surgical records or angiography, the work of building images was concluded. On cross section, grafts to LAD were visualized in all 10 cases: 9 in the entire course and 1 in a proximal part of the graft. Two to RCA, 4 to OM and 1 to a diagonal were also successfully visualized. Reconstruction of graft images succeeded in 9 grafts of 6 cases. The course of a graft could be pursued from the proximal to the distal end adjacent to the cardiac chamber. The picture of a bypass to LAD was visualized in 6 of 10 grafts. Two bypass to RCA could be depicted, and 1 to OM was also found. However 3 to OM and 1 to a diagonal failed to be visualized throughout their courses in reconstructed images. I think that the causes of faillure mainly depended upon the course of the graft. When a graft was running arc-like surrounding the heart chamber, it was very difficult to depict its entire length in reconstructed images, though the graft could be detected in cross sections. These preliminary studies indicated that reconstruction of CT images had some benefits for the pursuit of graft courses. (J.P.N.)

Inverse cutting of posterior lamellar corneal grafts by a femtosecond laser.

Science.gov (United States)

Hjortdal, Jesper; Nielsen, Esben; Vestergaard, Anders; Søndergaard, Anders

2012-01-01

Posterior lamellar grafting of the cornea has become the preferred technique for treatment of corneal endothelial dysfunction. Posterior lamellar grafts are usually cut by a micro-keratome or a femto-second laser after the epithelial side of the donor cornea has been applanated. This approach often results in variable central graft thickness in different grafts and an increase in graft thickness towards the periphery in every graft. The purpose of this study was to evaluate if posterior lamellar grafts can be prepared from the endothelial side by a femto-second laser, resulting in reproducible, thin grafts of even thickness. A CZM 500 kHz Visumax femto-second laser was used. Organ cultured donor grafts were mounted in an artifical anterior chamber with the endothelial side up and out. Posterior grafts of 7.8 mm diameter and 130 micron thickness were prepared by femto-second laser cutting. A standard DSAEK procedure was performed in 10 patients with Fuchs endothelial dystrophy. Patients were followed-up regularly and evaluated by measurement of complications, visual acuity, corneal thickness (Pentacam HR), and endothelial cell density. Femto-laser cutting of grafts and surgery was uncomplicated. Rebubbling was necessary in 5 of 10 cases (normally only in 1 of 20 cases). All grafts were attached and cleared up during the first few weeks. After six months, the average visual acuity was 0.30 (range: 0.16 to 0.50), corneal thickness was 0.58 mm (range 0.51 to 0.63), and endothelial cell density was 1.570 per sq. mm (range: 1.400 to 2.000 cells per sq. mm). The grafts were of uniform thickness, but substantial interface haze was present in most grafts. Posterior lamellar corneal grafts can be prepared from the endothelial side using a femto-second laser. All grafts were clear after 6 months with satisfying endothelial cell counts. Poor visual acuity caused by interface scatter was observed in most patients. Femto-second laser cutting parameters needs to be optimised to

Breeding graft-compatible Douglas-fir rootstocks (Pseudotsuga menziesii (Mirb.) Franco).

Science.gov (United States)

D.L. Copes

1999-01-01

A study encompassing 24 years was conducted to determine if a breeding program could produce highly graft-compatible rootstocks. Twenty-seven trees of apparent high graft compatibility were selected and crossed to produce 226 control-pollinated families. Seedlings were grown, field planted, and grafted with test scions. Graft unions from field tests were evaluated...

Fingertip Replantation Using Y-Shaped Vein Graft to Pulp Artery.

Science.gov (United States)

Kim, Jun Hyuk; Lee, Young Man

2015-10-01

Re-establishing adequate venous outflow is the most important factor for success of fingertip replantation. However, in zone I level, replantation is very difficult, especially in repairing venous circulation. The authors have made an attempt to replantation using Y-shaped vein (YSV) graft to identify and repair veins easily in fingertip replantation. From January 2007 to December 2012, a total of 46 fingertip replantations in 44 consecutive patients with amputations in the Tamai zone I level were performed by using YSV graft. In all patients, arterial anastomosis was performed using YSV graft, and interpositional vein grafts were used for venous repair. The overall success rate of the YSV-grafted replantations was 91.3% (42/46). Postoperative vascular complications occurred in 6 YSV-grafted replantations (13%), and pulp atrophy in the YSV-grafted digits was 9.5% (4/42). Fingertip replantation in zone I level is a difficult territory to a microsurgeon, especially anastomosing veins. However, our YSV grafting technique has shown value in this setting, enabling better esthetic and functional results.

Characterization of Functionalized Acrylic acid /4- Vinyl Pyridine Graft Copolymers

International Nuclear Information System (INIS)

Kamal, H.; Mahmoud, Gh.A.; Hegazy, D.E.

2009-01-01

Properties and characterization of the membranes prepared by radiation grafting of acrylic acid (AAc) or/ and 4-vinyl pyridine (4VP) onto low density polyethylene (LDPE) and polypropylene (PP) films were carried out. The FTIR spectra for the grafted membranes were studied to evaluate the structure change as a result of grafting. The swelling behaviour of the graft copolymer in methanol was studied. It was found that the grafting of AAc and/ or 4- VP onto LDPE and PP resulted in introducing good hydrophilic properties to such polymer substrates. The hydrophilic properties were directly proportional to the amount of functional groups. The mechanical properties (Young's modulus, elongation percent and tensile strength) of the grafted membranes also, have been investigated. As the grafting degree increases, the modulus also increases. Increasing the hydrophilicity of the membranes by chemical treatment enhances its mechanical properties. The thermal parameters of the grafted membranes such as δH m1 . δH m2 , and T rc have been also studied by using DSC

Composite vascular repair grafts via micro-imprinting and electrospinning

Energy Technology Data Exchange (ETDEWEB)

Liu, Yuanyuan, E-mail: yuanyuan-liu@shu.edu.cn; Hu, Qingxi, E-mail: huqingxi@shu.edu.cn [Rapid Manufacturing Engineering Center, Shanghai University, Shanghai 200444 (China); Shanghai Key Laboratory of Intelligent Manufacturing and Robotics, Shanghai 200072 (China); Xiang, Ke, E-mail: xiangke@shu.edu.cn; Chen, Haiping, E-mail: 519673062@qq.com; Li, Yu, E-mail: liyu@hpu.edu.cn [Rapid Manufacturing Engineering Center, Shanghai University, Shanghai 200444 (China)

2015-04-15

Composite vascular grafts formed by micro-imprinting and electrospinning exhibited improved mechanical properties relative to those formed by electrospinning alone. The three-layered composite grafts mimic the three-layered structure of natural blood vessels. The middle layer is made by micro-imprinting poly-p-dioxanone (PPDO), while the inner and outer layers are electrospun mixtures of chitosan and polyvinyl alcohol. The graft morphology is characterized with scanning electron microscopy. For constant graft thicknesses, the PPDO increases the mechanical strength. Cells cultivated on the vascular grafts adhere and proliferate better because of the natural, biological chitosan in the inner and outer layers. Overall, the composite scaffolds could be good candidates for blood vessel repair.

Transcriptomic Analysis Provides Insights into Grafting Union Development in Pecan (Carya illinoinensis).

Science.gov (United States)

Mo, Zhenghai; Feng, Gang; Su, Wenchuan; Liu, Zhuangzhuang; Peng, Fangren

2018-02-05

Pecan ( Carya illinoinensis ), as a popular nut tree, has been widely planted in China in recent years. Grafting is an important technique for its cultivation. For a successful grafting, graft union development generally involves the formation of callus and vascular bundles at the graft union. To explore the molecular mechanism of graft union development, we applied high throughput RNA sequencing to investigate the transcriptomic profiles of graft union at four timepoints (0 days, 8 days, 15 days, and 30 days) during the pecan grafting process. After de novo assembly, 83,693 unigenes were obtained, and 40,069 of them were annotated. A total of 12,180 differentially expressed genes were identified between by grafting. Genes involved in hormone signaling, cell proliferation, xylem differentiation, cell elongation, secondary cell wall deposition, programmed cell death, and reactive oxygen species (ROS) scavenging showed significant differential expression during the graft union developmental process. In addition, we found that the content of auxin, cytokinin, and gibberellin were accumulated at the graft unions during the grafting process. These results will aid in our understanding of successful grafting in the future.

Antibiotic Modification of Native Grafts: Improving upon nature's scaffolds

Science.gov (United States)

Ketonis, Constantinos

The use of allograft bone in orthopaedics, spine surgery and dentistry is invaluable for helping restore bone defects and promote osteointegration. However, one, and perhaps the most important, problem associated with the use of allograft is infection. It is a devastating complication for patients and physicians alike, and necessitates repeated surgeries, extended treatment and often times results in increased morbidity and poor outcomes. Previous attempts to incorporate antibiotics into allograft by soaking the graft in antibiotic solution have enjoyed limited success in providing adequate protection against bacterial colonization. To overcome problems associated with controlled release systems, I have described a novel chemical modification that allows for the attachment of vancomycin, or other antibiotics, to free amines of allograft bone thus rendering the graft bactericidal over a long time period. This modification, as evaluated by immunohistochemistry, allowed for the uniform and stable attachment of antibiotics to allograft without adversely affecting its potential for incorporation with bone. Modified allograft, placed in the presence of S. aureus, did not allow colonization by bacteria as evaluated by fluorescent imaging, scanning microscopy, and direct bacterial counts. More importantly, inhibition of bacterial colonization resulted in prevention of biofilm formation. Furthermore, I show that the spectrum of activity of the parent antibiotic was maintained, as the construct was not active against E. coli challenges. Comparison of this technology with simple antibiotic incorporation demonstrated that the covalently-coupled antibiotic did not elute from the bone, but rather remained attached and active on the surface for times out to one year, times that are far longer than currently can be achieved with the elution technologies. Despite its potent activity against bacteria, modified bone remained biocompatible allowing attachment of osteoblastic

Posttransplant sCD30 as a predictor of kidney graft outcome.

Science.gov (United States)

Süsal, Caner; Döhler, Bernd; Sadeghi, Mahmoud; Salmela, Kaija T; Weimer, Rolf; Zeier, Martin; Opelz, Gerhard

2011-06-27

Reliable markers for assessing the biological effect of immunosuppressive drugs and identification of transplant recipients at risk of developing rejection are not available. In a prospective multicenter study, we investigated whether posttransplant measurement of the T-cell activation marker soluble CD30 (sCD30) can be used for estimating the risk of graft loss in kidney transplant recipients. Pre- and posttransplant sera of 2322 adult deceased-donor kidney recipients were tested for serum sCD30 content using a commercial enzyme-linked immunosorbent assay. sCD30 decreased posttransplant and reached a nadir on day 30. Patients with a high sCD30 of more than or equal to 40 U/mL on day 30 showed a subsequent graft survival rate after 3 years of 78.3±4.1%, significantly lower than the 90.3±1.0% rate in recipients with a low sCD30 on day 30 of less than 40 U/mL (log-rank PsCD30 levels, patients with high sCD30 on posttransplant day 30 demonstrated significantly lower 3-year graft survival irrespective of the pretransplant level. Our data suggest that posttransplant measurement of sCD30 on day 30 is a predictor of subsequent graft loss in kidney transplant recipients and that sCD30 may potentially serve as an indicator for adjustment of immunosuppressive medication.

Dynamics of solvent-free grafted nanoparticles

KAUST Repository

Chremos, Alexandros

2012-01-01

The diffusivity and structural relaxation characteristics of oligomer-grafted nanoparticles have been investigated with simulations of a previously proposed coarse-grained model at atmospheric pressure. Solvent-free, polymer-grafted nanoparticles as well as grafted nanoparticles in a melt were compared to a reference system of bare (ungrafted) particles in a melt. Whereas longer chains lead to a larger hydrodynamic radius and lower relative diffusivity for grafted particles in a melt, bulk solvent-free nanoparticles with longer chains have higher relative diffusivities than their short chain counterparts. Solvent-free nanoparticles with short chains undergo a glass transition as indicated by a vanishing diffusivity, diverging structural relaxation time and the formation of body-centered-cubic-like order. Nanoparticles with longer chains exhibit a more gradual increase in the structural relaxation time with decreasing temperature and concomitantly increasing particle volume fraction. The diffusivity of the long chain nanoparticles exhibits a minimum at an intermediate temperature and volume fraction where the polymer brushes of neighboring particles overlap, but must stretch to fill the interparticle space. © 2012 American Institute of Physics.

Radiation induced graft copolymerization of acrylamide onto poly (3-hydroxybutyrate)

International Nuclear Information System (INIS)

Gonzalez Torres, Maykel; Rapado Paneque, Manuel; Paredes Zaldivar, Mayte; Altanes Valentin, Sonia; Barrera Gonzalez, Gisela

2008-01-01

The graft copolymer poly (3-hydroxybutyrate)-g- polyacrylamide [P (HB-g-AAm)] was synthesized by radiation induced graft copolymerization of acrylamide onto poly (3-hydroxybutyrate). The study was conducted by the simultaneous irradiation method. The structure of [P (HB-g-AAm)] was identified by Fourier Transform Infrared (FTIR) spectroscopy. Thermal behavior of the graft copolymer was also studied by Thermal Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). From the results it was found that FTIR studies showed new signals (stretching -N-H) as strong evidence of grafting. The grafting degree was found to be 10 % and the thermodynamic parameter obtained from the DSC thermogram of plain PHB and the graft copolymer varied showing decrease in the material crystallinity and increase in the glass transition temperature. These results demonstrate that the radiation induced graft copolymerization reaction of acrylamide onto PHB was successively achieved. (Author)

Magnetizable stent-grafts enable endothelial cell capture

Science.gov (United States)

Tefft, Brandon J.; Uthamaraj, Susheil; Harburn, J. Jonathan; Hlinomaz, Ota; Lerman, Amir; Dragomir-Daescu, Dan; Sandhu, Gurpreet S.

2017-04-01

Emerging nanotechnologies have enabled the use of magnetic forces to guide the movement of magnetically-labeled cells, drugs, and other therapeutic agents. Endothelial cells labeled with superparamagnetic iron oxide nanoparticles (SPION) have previously been captured on the surface of magnetizable 2205 duplex stainless steel stents in a porcine coronary implantation model. Recently, we have coated these stents with electrospun polyurethane nanofibers to fabricate prototype stent-grafts. Facilitated endothelialization may help improve the healing of arteries treated with stent-grafts, reduce the risk of thrombosis and restenosis, and enable small-caliber applications. When placed in a SPION-labeled endothelial cell suspension in the presence of an external magnetic field, magnetized stent-grafts successfully captured cells to the surface regions adjacent to the stent struts. Implantation within the coronary circulation of pigs (n=13) followed immediately by SPION-labeled autologous endothelial cell delivery resulted in widely patent devices with a thin, uniform neointima and no signs of thrombosis or inflammation at 7 days. Furthermore, the magnetized stent-grafts successfully captured and retained SPION-labeled endothelial cells to select regions adjacent to stent struts and between stent struts, whereas the non-magnetized control stent-grafts did not. Early results with these prototype devices are encouraging and further refinements will be necessary in order to achieve more uniform cell capture and complete endothelialization. Once optimized, this approach may lead to more rapid and complete healing of vascular stent-grafts with a concomitant improvement in long-term device performance.