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

Prolongation of rat islet allograft survival by direct ultraviolet irradiation of the graft

International Nuclear Information System (INIS)

Lau, H.; Reemtsma, K.; Hardy, M.A.

1984-01-01

Ultraviolet irradiation of rat dendritic cells completely abrogated their allostimulatory capacity in a mixed lymphocyte reaction. Rat islets of Langerhans similarly irradiated remained hormonally functional when transplanted into syngeneic diabetic rats. Allogeneic transplantation across a major histocompatibility barrier of islets initially treated in vitro with ultraviolet irradiation resulted in prolonged allograft survival without the use of any immunosuppressive agents

Post irradiation effects on the graft of poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) (PFA) films

International Nuclear Information System (INIS)

Geraldes, Adriana N.; Zen, Heloisa A.; Ribeiro, Geise; Ferreira, Henrique P.; Souza, Camila P.; Parra, Duclerc F.; Lugao, Ademar B.

2009-01-01

Radiation induced grafting of monomers into fluorinated polymers was designed as an alternative route to polymer modification. In this work, grafting of styrene onto poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) (PFA) was studied. Radiation-induced grafting of styrene onto PFA films was investigated after simultaneous irradiation (in post-irradiation condition) using a 60 Co source. The films of PFA were irradiated at 20, 40, 80 and 100 kGy doses at room temperature and chemical changes were monitored after contact with styrene for grafting. The post-irradiation time was established between 7 and 28 days when films of PFA were maintained in styrene/toluene 1:1 v/v solution at room temperature. After these periods the grafting degrees were evaluated in the samples. The highest degree of grafting was achieved after 14 days. Chemical modifications were evaluated by infrared spectroscopic analysis (FTIR), thermogravimetry (TG), differential scanning calorimetry (DSC) and also by scanning electron microscopy (SEM). The degree of grafting (DOG) was determined gravimetrically. The results showed that irradiated PFA films at 100 kGy exhibited higher grafting degree. Surface analysis by SEM technique of irradiated, grafted and original films have presented an homogeneous surface. (author)

Grafting of polymer onto silica surface in the presence of γ-ray irradiated silica

International Nuclear Information System (INIS)

Tsuchida, A.; Yokoyama, R.; Takami, M.; Chen, J.; Ohta, M.; Tsubokawa, N.

2002-01-01

Complete text of publication follows. We have reported the graft polymerization of vinyl monomers initiated by surface radicals formed by the decomposition of azo and peroxide groups previously introduced onto the surface. In addition, the grafting of polymers onto carbon black has been reported by the reaction of polymer radicals with the surface. On the other hand, it is well known that the relatively stable radicals are generated on the surface by the γ-ray irradiation. In this paper, the grafting of polystyrene onto silica surface during the thermal polymerization of styrene in the presence of γ-ray irradiated silica, grafting mechanism and thermal stability of grafted polymer will be discussed. The grafting of polymers onto silica surface by irradiation of polymer-adsorbed silica was also investigated. Silica obtained from Mitsubishi Chemical Co., Japan was used after pulverization: the particle size was 0.037-0.088 mm. Irradiation was performed in Cs-137 source at room temperature. The silica was irradiated at 50 Gy with dose rate of 3.463 Gy/min. Into a polymerization tube, styrene and irradiated silica was charged and the polymerization was carried out under argon under stirring. The percentage of polystyrene grafting was determined from weight loss when polystyrene-grafted silica was heated at 600 deg C by a thermal analyzer. Untreated silica did not affect the thermal polymerization of styrene. On the contrary, the thermal polymerization of styrene was remarkably retarded in the presence of the irradiated silica at 60 deg C. Similar tendency was reported during the polymerization of vinyl monomers in the presence of carbon black. In the initial stage of the polymerization in the presence of the irradiated silica below 50 deg C, the polymerization was accelerated. During the polymerization in the presence of irradiated silica, polystyrene was grafted onto the surface: the percentage of grafting was 5-11%. The amount of polystyrene grafted onto silica

Postoperative irradiation after reconstructive surgery: comparative study of radiosensitivity between free-skin grafts and skin flaps

International Nuclear Information System (INIS)

Sumi, Y.; Ueda, M.; Kaneda, T.; Oka, T.; Torii, S.; Sakuma, S.

1984-01-01

Radiation effects after reconstructive surgery (free-skin grafts and skin flaps) were studied in the rat, and the optimum time for irradiation was determined. The radiosensitivity of both free-skin grafts and skin flaps showed the same trend depending on time of irradiation after operation. The grafts or flaps irradiated in the hypervascular stage showed severe reactions to irradiation, whereas those irradiated in the hypovascular stage showed milder reactions in gross and microangiographic observation. Vascular damage should be given primary consideration when deciding the proper time for irradiation after reconstructive surgery. In general, free-skin grafts showed more severe reactions than skin flaps, especially in the grafts irradiated in the early stage after operation. The experimental results of this study cannot be readily transferred to a clinical setting, but they suggest that postoperative irradiation could be begun 3 to 4 weeks after operation with respect to graft or flap survival, and the results of the clinical cases almost coincide with these experimental results

Allograft tolerance in pigs after fractionated lymphoid irradiation. I. Skin grafts after partial lateral irradiation and bone marrow cell grafting

International Nuclear Information System (INIS)

Vaiman, M.; Daburon, F.; Remy, J.; Villiers, P.A.; de Riberolles, C.; Lecompte, Y.; Mahouy, G.; Fradelizi, D.

1981-01-01

Experiments with pigs have been performed to establish bone marrow chimerism and skin graft tolerance between SLA genotyped animals. Recipients were conditioned by means of fractionated partial irradiation from lateral cobalt sources (partial lateral irradiation (PLI)). The head, neck, and lungs were protected with lead, the rest of the body being irradiated including the thymus, the majority of lymphoid organs with spleen, and most of the bone marrow sites

An analysis of facial nerve function in irradiated and unirradiated facial nerve grafts

International Nuclear Information System (INIS)

Brown, Paul D.; Eshleman, Jeffrey S.; Foote, Robert L.; Strome, Scott E.

2000-01-01

Purpose: The effect of high-dose radiation therapy on facial nerve grafts is controversial. Some authors believe radiotherapy is so detrimental to the outcome of facial nerve graft function that dynamic or static slings should be performed instead of facial nerve grafts in all patients who are to receive postoperative radiation therapy. Unfortunately, the facial function achieved with dynamic and static slings is almost always inferior to that after facial nerve grafts. In this retrospective study, we compared facial nerve function in irradiated and unirradiated nerve grafts. Methods and Materials: The medical records of 818 patients with neoplasms involving the parotid gland who received treatment between 1974 and 1997 were reviewed, of whom 66 underwent facial nerve grafting. Fourteen patients who died or had a recurrence less than a year after their facial nerve graft were excluded. The median follow-up for the remaining 52 patients was 10.6 years. Cable nerve grafts were performed in 50 patients and direct anastomoses of the facial nerve in two. Facial nerve function was scored by means of the House-Brackmann (H-B) facial grading system. Twenty-eight of the 52 patients received postoperative radiotherapy. The median time from nerve grafting to start of radiotherapy was 5.1 weeks. The median and mean doses of radiation were 6000 and 6033 cGy, respectively, for the irradiated grafts. One patient received preoperative radiotherapy to a total dose of 5000 cGy in 25 fractions and underwent surgery 1 month after the completion of radiotherapy. This patient was placed, by convention, in the irradiated facial nerve graft cohort. Results: Potential prognostic factors for facial nerve function such as age, gender, extent of surgery at the time of nerve grafting, preoperative facial nerve palsy, duration of preoperative palsy if present, or number of previous operations in the parotid bed were relatively well balanced between irradiated and unirradiated patients. However

Radiosensitivity of T and B lymphocytes. V. Effects of whole-body irradiation on numbers of recirculating T cells and sensitization to primary skin grafts in mice

International Nuclear Information System (INIS)

Anderson, R.E.; Williams, W.L.

1977-01-01

Whole-body exposure of mice to 50, 100, 300, or 500 rads results in an acute dose-related decrease in the number of viable recirculating T cells. The magnitude of this decrement becomes more pronounced with the passage of time. The dose-response relationship over this range of dosages appears to consist of three components: a steep drop between 0 and 50 rads, a plateau between 50 and 500 rads, and a second drop between 300 and 500 rads. The residual radioresistant cells are able to recognize a histoincompatible skin graft during the initial 5 days after irradiation. Low to moderate doses (50 to 300 rads) abrogate the partial tolerance noted in nonirradiated recipients exposed to the skin graft for 5 days and then regrafted from the same donor source 25 days after complete removal of the primary graft. A large (500 rads) dose results in prolonged graft survival in comparison with the nonirradiated group. It is suggested that the subpopulation of recirculating T cells which develops partial tolerance during a 5-day exposure to a homograft is more radiosensitive than the effector subpopulation which is involved in graft rejection

Influences of irradiation on the anastomotic sites of artificial graft

International Nuclear Information System (INIS)

Ogawa, Junichi; Inoue, Hiroshi; Koide, Shirosaku; Kawada, Shimei; Shotsu, Akira

1989-01-01

To examine the acute influences of irradiation on the anastomotic sites of EPTFE vascular grafts, experimental study was performed using canine dogs. After replacement of superior vena cava and bilateral femoral arteries with EPTFE grafts, a total of 20 to 100 Gy doses were given at the anastomotic sites of superior vena cava and right femoral artery. There were no degradation of grafts themselves or rupture in the anastomoses at cumulative anastomotic sites of superior vena cava, stenoses and/or overgrowth of granulation tissues were observed, although at those of right femoral artery, no remarkable differences were observed between dogs which received irradiation and those which did not receive. (author)

Preparation of vinyl acetate grafted natural rubber by irradiation method

Energy Technology Data Exchange (ETDEWEB)

Porntrairat, A.; Pattamaprom, C. [Center of Excellence on Natural Rubber Technology, Department of Chemical Engineering, Faculty of Engineering, Thammasat University, Pathumthani 12120 (Thailand)

2016-03-09

Improvement in properties of natural rubber could be done by several methods. In this research, gamma radiation technique, which is simple, accurate, easy to control and clean, was applied to enhance the properties of natural rubber (NR) in latex state. The purpose of this research is to study the appropriate condition for preparing grafted natural rubber latex by using irradiation method. Vinyl acetate monomers (VAc) were grafted onto natural rubber latex (NR-g-PVAc) at 0-10 kGys by gamma radiation from Cobalt-60 source at room temperature. Physical properties of grafted natural rubber such as chloroform number, swelling ratio and gel content were measured. The VAc content of NR-g-PVAc was investigated by titration and visualized by FTIR spectroscopy. The FTIR spectra of NR-g-PVAc prepared at 0-10 kGys showed characteristic peaks of the vinyl acetate confirming that VAc could be grafted onto natural rubber molecular chains effectively under appropriate irradiation conditions. From the result, radiation grafting was found to be a useful technique for grafting of vinyl acetate onto natural rubber.

Allograft tolerance in pigs after fractionated lymphoid irradiation. II. Kidney graft after conventional total lymphoid irradiation and bone marrow cell grafting

International Nuclear Information System (INIS)

Fradelizi, D.; Mahouy, G.; de Riberolles, C.; Lecompte, Y.; Alhomme, P.; Douard, M.C.; Chotin, G.; Martelli, H.; Daburon, F.; Vaiman, M.

1981-01-01

Experiments with pigs have been performed in order to establish bone marrow chimerism and kidney graft tolerance between SLA genotyped semi-incompatible animals. Recipients were conditioned by means of conventional fractionated total lymphoid irradiation (TLI) delivered by a vertical cobalt source. The principal lymphoid regions of the pig, including thymus and spleen, were submitted to irradiation. Two protocols were tested: A = 250 cGy four times a week x 13 times (TLI) (two animals) and B = 350 cGy three times a week x 8 times (TLI) (four animals). Bone marrow cells were injected 24 h after the last irradiation. One day later, bilateral nephrectomy and the graft of one kidney from the bone marrow cell donor were performed simultaneously. Results convinced us that application of the TLI protocol to humans is not yet practicable and that further experimental work is needed

500-Gray γ-Irradiation May Increase Adhesion Strength of Lyophilized Cadaveric Split-Thickness Skin Graft to Wound Bed.

Science.gov (United States)

Wei, Lin-Gwei; Chen, Chieh-Feng; Wang, Chi-Hsien; Cheng, Ya-Chen; Li, Chun-Chang; Chiu, Wen-Kuan; Wang, Hsian-Jenn

2017-03-01

Human cadaveric skin grafts are considered as the "gold standard" for temporary wound coverage because they provide a more conductive environment for natural wound healing. Lyophilization, packing, and terminal sterilization with gamma-ray can facilitate the application of cadaveric split-thickness skin grafts, but may alter the adhesion properties of the grafts. In a pilot study, we found that 500 Gy γ-irradiation seemed not to reduce the adherence between the grafts and wound beds. We conducted this experiment to compare the adherences of lyophilized, 500-Gy γ-irradiated skin grafts to that of lyophilized, nonirradiated grafts. Pairs of wounds were created over the backs of Sprague- Dawley rats. Pairs of "lyophilized, 500-Gy γ-irradiated" and "lyophilized, nonirradiated" cadaveric split-thickness skin grafts were fixed to the wound beds. Adhesion strength between the grafts and the wound beds was measured and compared. On post-skin-graft day 7 and day 10, the adhesion strength of γ-irradiated grafts was greater than that of the nonirradiated grafts. Because lyophilized cadaveric skin grafts can be vascularized and the collagen of its dermal component can be remodeled after grafting, the superior adhesion strength of 500-Gy γ-irradiated grafts can be explained by the collagen changes from irradiation.

Solvent effect on post-irradiation grafting of styrene onto poly(ethylene-alt-tetrafluoroethylene) (ETFE) films

Science.gov (United States)

Napoleão Geraldes, Adriana; Augusto Zen, Heloísa; Ribeiro, Geise; Fernandes Parra, Duclerc; Benévolo Lugão, Ademar

2013-03-01

Radiation-induced grafting of styrene onto ETFE films in different solvent was investigated after simultaneous irradiation (in post-irradiation condition) using a 60Co source. Grafting of styrene followed by sulfonation onto poly(ethylene-alt-tetrafluoroethylene) (ETFE) are currently studied for synthesis of ion exchange membranes. The ETFE films were immersed in styrene/toluene, styrene/methanol and styrene/isopropyl alcohol and irradiated at 20 and 100 kGy doses at room temperature. The post-irradiation time was established at 14 day and the grafting degree was evaluated. The grafted films were sulfonated using chlorosulfonic acid and 1,2-dichloroethane 20:80 (v/v) at room temperature for 5 h. The degree of grafting (DOG) was determined gravimetrically and physical or chemical changes were evaluated by differential scanning calorimeter analysis (DSC), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The ion exchange capacity (IEC) values showed the best performance of sulfonation for ETFE membranes grafted in toluene solvent. Surface images of the grafted films by SEM technique have presented a strong effect of the solvents on the films morphology.

Preparation of antifouling ultrafiltration membranes via irradiation induced graft polymerization technique

International Nuclear Information System (INIS)

Deng Bo; Liu Zhognying; Lu Xiaofeng; Li Jingye; Yang Xuanxuan; Yu Ming; Zhang Bowu

2010-01-01

PVDF powders were irradiated in air at dose of 15 kGy by using gamma-rays. Macromolecular peroxides transformed from free radicals in the irradiated PVDF powders in air can be preserved for long-term at appropriate temperature stably. By mixing acrylic monomers with irradiated PVDF powders then the graft polymerization can be initiated by heating. Then a series of hydrophilic ultrafiltration (UF) membranes were fabricated by dissolving the PVDF-g-PAAc powders in the NMP under phase inversion method. The antifouling performances of UF membranes cast from virgin and grafted PVDF powders were compared. (authors)

Selective induction of cyclin B protein abrogates the G2 delay after irradiation

International Nuclear Information System (INIS)

Kao, G.; Muschel, R.J.; Maity, A.; Kunig, A.; McKenna, W.G.

1996-01-01

Purpose/Objective: Irradiation of tumor cells commonly results in G2 delay, which has been postulated to allow DNA repair and cell survival. The G2 delay after irradiation is also often marked in some cell lines by delayed expression of cyclin B protein, suggesting a role for cyclin B regulation. Investigations of these hypotheses however has been hampered by the inability to selectively perturb the G2 delay in a physiologic manner. Materials and Methods: We have devised a system, with which we are able to selectively induce cyclin B protein expression in vivo at specific points in the cell cycle, by transfecting Hela cells with an expression vector under control of a dexamethasone-inducible promoter. Experiments were subsequently performed by synchronizing, releasing, irradiating, inducing, and harvesting these cells through the cell cycle. Results: Irradiation with 5 Gy led to a pronounced G2 delay, reflected by markedly slowed progression into mitosis, concomitant with reduced expression of cyclin B protein. Induction of cyclin B after radiation in these cells abrogated the G2 delay by approximately doubling the rate at which the cells re-enter mitosis. Treatment of irradiated untransfected control cells with dexamethasone, in which cyclin B is not induced, led to minimal changes. Studies of effects of cyclin B induction on cyclin B localization (using immunofluorescence), cdc2 phosphorylation and activation will also be presented. Conclusion: This system should allow further investigations into fundamental mechanisms of cell cycle regulation after irradiation and DNA damage. This also provides direct evidence for the first time that cyclin B protein regulation may play a role in the G2 delay following irradiation in Hela cells, perhaps complementing phosphorylation events

Grafting of HEMA onto dopamine coated stainless steel by 60Co-γ irradiation method

International Nuclear Information System (INIS)

Jin, Wanqin; Yang, Liming; Yang, Wei; Chen, Bin; Chen, Jie

2014-01-01

A novel method for grafting of 2-hydroxyethyl methacrylate (HEMA) onto the surface of stainless steel (SS) was explored by using 60 Co-γ irradiation. The surface of SS was modified by coating of dopamine before radiation grafting. The grafting reaction was performed in a simultaneous irradiation condition. The chemical structures change of the surface before and after grafting was demonstrated by Fourier transform infrared (FTIR) spectrometer. The hydrophilicity of the samples was determined by water contact angle measurement in the comparison of the stainless steel in the conditions of pristine, dopamine coated and HEMA grafted. Surface morphology of the samples was characterized by atomic force microscope (AFM) and scanning electron microscope (SEM). The corrosion resistance properties of the samples were evaluated by Tafel polarization curve. The hemocompatibility of the samples were tested by platelet adhesion assay. - Highlights: • Poly-HEMA was grafted onto the surface of SS by 60 Co-γ-ray irradiation. • Pristine SS was coated by dopamine to form a dense poly-dopamine film before radiation grafting. • The biocompatibility and hydrophility of SS were improved after the grafting of HEMA

Preliminary studies on 1-vinyl-2-pyrrolidone grafting onto cellulose by pre-irradiation method

Energy Technology Data Exchange (ETDEWEB)

Severich, Patrick; Dutra, Rodrigo da Costa; Kodama, Yasko, E-mail: ykodama@ipen.br, E-mail: patrick.severich@ipen.br, E-mail: rodrigo.dutra@ipen.br [Instituto de Pesquisas Energética s e Nucleares (IPEN-CNEN/SP), São Paulo, SP (Brazil)

2017-07-01

Cellulose is considered a renewable biopolymer most abundant in nature. Better functional surfaces can be Obtained by modifying cellulose. On the other hand, poly vinyl pyrrolidone, PVP, is a synthetic nontoxic, water-soluble polymer frequently used in an extensive variety of applications including several pharmaceutical applications. Grafting 1-vinyl-2-pyrrolidone, NVP, onto polymeric cellulose can be obtained by ionizing radiation. Ionizing radiation grafting can be affected by several factors as environment, solvent, monomer concentration, temperature of graft reaction. Grafting by ionizing radiation can be performed by three methods, pre-irradiation, oxidation by peroxide and simultaneous irradiation. In this study, it was used pre-irradiation method of cellulose. Paper filter without ash, NVP without purification was used in this study. Paper samples were exposed to electron beam from Dynamitron Accelerator with radiation absorbed dose of 25 kGy. Influence of NVP concentration, temperature of reaction after irradiation on degree of grafting (DG) was studied. Also, cellulose radicals of grafted paper samples was studied by electron paramagnetic resonance using a Bruker X-band ESR at room temperature just after heating reaction. Small decrease of cellulose radicals was observed with increasing reaction temperature. It was observed DG small increase with increasing concentration of monomer in solution of water ethanol 50-50 v:v and rising temperature of reaction. Further tests using simultaneous method of grafting of NVP in cellulose paper, in water:ethanol 75:25 v:v solution, induced by gamma irradiation were performed. It was observed homopolymerization forming PVP with increasing monomer concentration. (author)

Preliminary studies on 1-vinyl-2-pyrrolidone grafting onto cellulose by pre-irradiation method

International Nuclear Information System (INIS)

Severich, Patrick; Dutra, Rodrigo da Costa; Kodama, Yasko

2017-01-01

Cellulose is considered a renewable biopolymer most abundant in nature. Better functional surfaces can be Obtained by modifying cellulose. On the other hand, poly vinyl pyrrolidone, PVP, is a synthetic nontoxic, water-soluble polymer frequently used in an extensive variety of applications including several pharmaceutical applications. Grafting 1-vinyl-2-pyrrolidone, NVP, onto polymeric cellulose can be obtained by ionizing radiation. Ionizing radiation grafting can be affected by several factors as environment, solvent, monomer concentration, temperature of graft reaction. Grafting by ionizing radiation can be performed by three methods, pre-irradiation, oxidation by peroxide and simultaneous irradiation. In this study, it was used pre-irradiation method of cellulose. Paper filter without ash, NVP without purification was used in this study. Paper samples were exposed to electron beam from Dynamitron Accelerator with radiation absorbed dose of 25 kGy. Influence of NVP concentration, temperature of reaction after irradiation on degree of grafting (DG) was studied. Also, cellulose radicals of grafted paper samples was studied by electron paramagnetic resonance using a Bruker X-band ESR at room temperature just after heating reaction. Small decrease of cellulose radicals was observed with increasing reaction temperature. It was observed DG small increase with increasing concentration of monomer in solution of water ethanol 50-50 v:v and rising temperature of reaction. Further tests using simultaneous method of grafting of NVP in cellulose paper, in water:ethanol 75:25 v:v solution, induced by gamma irradiation were performed. It was observed homopolymerization forming PVP with increasing monomer concentration. (author)

Studies on the properties of poly (ethylene oxide) R-150 hydrogel films formed by irradiation graft

International Nuclear Information System (INIS)

Yang Zhanshan; Zhu Nankang; Yang Shuqin; Qiang Yizhong

1999-01-01

In order to improve the mechanical properties of poly (ethylene oxide) (PEO) hydrogel film was used as wound dressing. The chemical and physical properties of the PEO R-150 graft hydrogel film formed by blends of electron beam irradiated-PEO R-150 and poly(vinyl alcohol) (PVA) were studied. The experimental results showed that the crosslinking densities of the PEO R-150 graft hydrogel increased along with the increasing of the irradiation doses and decreased with the increasing of the blend concentrations. While the PVA graft proportions did not produce obvious effects on the crosslinking density of the graft hydrogel. The crosslinking density of the graft hydrogel were obviously lower than that of the pure PVA hydrogel. The equilibrium water content of the graft hydrogel decrease as the irradiation dose and the PVA graft proportion increased; but they increased as the blend concentration increased. The equilibrium water content of the graft hydrogel was obviously higher than those of the pure PVA hydrogel. The hardness of the PVA hydrogel film increased with the irradiation dose. The hardness of the graft hydrogel decreased with the blend concentration, whereas it increased with the PVA graft proportion. The results suggest the PVA produces a main effect on the crosslinking density of the graft hydrogel, the PEO R-150 produces a main effect on the equilibrium water content of the graft hydrogel, and the both polymers have double effects on the hardness of the graft hydrogel

Obtaining cherry and apple tree radiomutants by irradiation of grafts in gamma cell

International Nuclear Information System (INIS)

Chvojka, L.; Fridrich, A.

1980-01-01

The aim of the study was to obtain dwarf mutants of cherry and apple trees. Two methods of irradiation were used: a) winter grafts were irradiated with 60 Co (4-5 kR) and grafted in the crowns of adult trees or of two-year-old rootstocks; b) summer buds on mature annual shots were irradiated with 2-3 kR and grafted on two-year-old rootstocks. Thus the clones of dwarf cherry trees (cv. Napoleon's and Techlovicka) were obtained which were further tested for fruit-bearing in experimental plantations. Colour mutants of apple tree (cv. Champion) with yellow and red fruits were also obtained as well as dwarf types of trees. (author)

Grafting of acrylic acid onto polypropylene films irradiated with argon ions

International Nuclear Information System (INIS)

Massa, G.; Mazzei, R.; Garcia Bermudez, G.; Filevich, A.; Smolko, E.

2005-01-01

Polypropylene (PP) foils were irradiated with 100 keV energy Argon ions at different fluences ranging from 10 12 up to 2 x 10 15 cm -2 and then grafted with acrylic acid (AA). The grafting yield was measured by weight difference and the structural changes on the films were analysed using Fourier transform infrared spectroscopy (FTIR). Different parameters that determined the grafting process such us fluence, grafting time and monomer concentration were analysed. The grafting reached an optimum value at 79% in aqueous solution at 30 min grafting time. The grafting yield as a function of the ion fluence plot, presented a maximum value, as previously found in a study of heavy beam on polymers

Graft Copolymerization of Methyl Methacrylate Monomer onto Starch and Natural Rubber Latex Initiated by Gamma Irradiation

Directory of Open Access Journals (Sweden)

S. Iskandar

2011-04-01

Full Text Available To obtain the degradable plastic, the graft copolymerization of methyl methacrylate onto starch and natural rubber latex was conducted by a simultaneous irradiation technique. Gamma-ray from cobalt-60 source was used as the initiator. The grafted copolymer of starch-polymethyl methacrylate and the grafted copolymer of natural rubber-polymethyl methacrylate were mixed in the blender, and dried it in the oven. The dried grafted copolymer mixture was then molded using hydraulic press machine. The effect of irradiation dose, composition of the grafted copolymer mixture, film forming condition and recycle effect was evaluated. The parameters observed were tensile strength, gel fraction and soil burial degradability of grafted copolymer mixture. It was found that the tensile strength of grafted copolymer mixture increased by -ray irradiation. Increasing of the grafted copolymer of natural rubber-polymethyl methacrylate content, the gel fraction and tensile strength of the grafted copolymer mixture increased. The tensile strength of the grafted copolymer mixture was increased from 18 MPa to 23 MPa after recycled (film forming reprocessed 3 times. The grafted copolymer mixture was degraded completely after soil buried for 6 months

Hydrophilicity improvement of polyethersulfone membranes by grafting methacrylic acid with γ-ray irradiation

International Nuclear Information System (INIS)

Li Jing; Hou Zhengchi; Xie Leidong; Zhang Fengying; Deng Bo

2005-01-01

Grafting methyacrylic acid onto poly(ether sulfone) membranes was realized by means of simultaneous irradiation in liquids. The modified membranes with different grafting ratios were obtained by changing the concentration of methyacrylic acid. It was shown that the grafting ratio increased lineally as the monomer concentration was less than 10% and hydrophilicity of the membranes was improved with increasing grafting ratios. (authors)

Study on the properties of blend rubber prepared with grafted rubber and irradiated rubber by Gamma Rays

International Nuclear Information System (INIS)

Dafader, N. C.; Haque, M. E.; Islam, K. A.

2004-05-01

The blend rubbers were prepared by mixing γ-rays irradiated and monomer grafted rubbers. The monomers, methyl methacrylate (MMA) and styrene were used separately to prepare grafted rubber by exposure to radiation. The physico-chemical properties of the blend rubbers were evaluated. The tensile strength and elongation at break of the blend rubbers decrease whereas modulus at 500% elongation, swelling ratio and permanent set increase with the increased proportion of grafted rubber in the blend. The tear strength of the blend between irradiated and styrene grafted rubbers increases with the increased proportion of grafted rubber but that of the blend of irradiated and MMA grafted rubbers remains almost constant. The blend rubber could be used for special type of application like rubber thread, tube, catheter etc

Synthesis and Characterization of Konjac Glucomannan-Graft-Polyacrylamide via γ-Irradiation

Directory of Open Access Journals (Sweden)

Jie Pang

2008-03-01

Full Text Available The synthesis of konjac glucomannan-graft-polyacrylamide (KGM-g-PAM wascarried out at 25°C by γ-irradiation under a N2 atmosphere. The effects of absorbedradiation dosage and monomer concentration on grafting yield and water absorbency werestudied. The grafted copolymers were characterized using Fourier Transform Infrared(FTIR spectroscopy, nuclear magnetic resonance (NMR, x-ray diffraction (XRD,thermogravimetric analysis (TGA and gel permeation chromatography (GPC. Thegrafting yield was observed to increase with increasing absorbed dosage and monomerconcentration. Compared with the original KGM, the grafted copolymers exhibited betterthermal stability and water absorbency. The results suggest that γ-irradiation is convenientand efficient for inducing graft copolymerization of KGM and acrylamide (AM.

Pre-irradiation grafting of hydrophilic monomers onto polyethylene: Pt. 1

International Nuclear Information System (INIS)

Gargan, K.; Kronfli, E.; Lovell, K.V.

1990-01-01

An investigation was carried out to identify compounds which are suitable for use as homopolymerisation inhibitors when grafting acrylic acid or methacrylic acid onto pre-irradiated low-density polyethylene. It was found that certain transition metal compounds were able to suppress the formation of homopolymer whilst still allowing significant levels of grafting to take place. For acrylic acid the most suitable inhibitor found was ferrous sulphate, whilst cupric sulphate or potassium ferrocyanide were favoured for use with methacrylic acid. The influence of the inhibitor concentration on the degree of grafting was also investigated. (author)

Free and microvascular bone grafting in the irradiated dog mandible

International Nuclear Information System (INIS)

Altobelli, D.E.; Lorente, C.A.; Handren, J.H. Jr.; Young, J.; Donoff, R.B.; May, J.W. Jr.

1987-01-01

Microvascular and free rib grafts were placed in 4.5 cm defects in an edentate mandibular body defect 18 to 28 days after completion of 50 Gy of irradiation from a 60 Co source. The animals were sacrificed from two to forty weeks postoperatively and evaluated clinically, radiographically, and histologically. There was a marked difference in the alveolar mucosal viability with the two grafts. Mucosal dehiscence was not observed over any of the microvascular grafts, but was present in seven-eighths of the free grafts. Union of the microvascular bone graft to the host bone occurred within six weeks. In contrast, after six weeks the free graft was sequestered in all the animals. An unexpected finding with both types of graft was the marked subperiosteal bone formation. This bone appeared to be derived from the host bed, stabilizing and bridging the defects bilaterally. The results suggest that radiated periosteum may play an important role in osteogenesis

Graft copolymerization of glycidyl methacrylate onto delignified kenaf fibers through pre-irradiation technique

International Nuclear Information System (INIS)

Sharif, Jamaliah; Mohamad, Siti Fatahiyah; Fatimah Othman, Nor Azilah; Bakaruddin, Nurul Azra; Osman, Hasnul Nizam; Güven, Olgun

2013-01-01

Glycidyl methacrylate grafted kenaf (GMA-g-Kenaf) was prepared by pre-irradiation grafting technique. Kenaf fibers were treated with different concentration of sodium chlorite solution before used as trunk polymer. Treated kenaf fibers were irradiated by electron beam followed by grafting reaction in GMA/water emulsion system. The degree of grafting was determined as a function of absorbed dose, reaction time, reaction temperature and concentration of monomer. The results showed that the lignin content was decreased from 14.3% to as low as 3.3% with the increased of sodium chlorite concentration. This was evidenced by SEM pictures which show the surface of treated kenaf fibers was cleaner and smoother compared to that of untreated one. The degree of grafting increased with the increase of absorbed dose, reaction temperature, reaction time and monomer concentration as well as with decreasing lignin content. Formation of graft copolymer was confirmed with SEM, FTIR analysis. The structural investigation by XRD showed that degree of crystallinity of graft copolymers decreased with the increase in degree of grafting. - Highlights: • We used kenaf fibers for radiation induce graft copolymerization with GMA. • Kenaf fibers was treated to remove lignin in order to increase grafting yield. • Treated kenaf fibers were graft copolymerize through preirradiation technique. • Optimum conditions for graft copolymerization of kenaf fibers were established. • Formation of graft copolymer is also confirmed with SEM, FTIR and XRD

Graft-copolymerization of polyethersulfone microporous membrane with electron beam simultaneous irradiation method

International Nuclear Information System (INIS)

Han Zhaolei; Meng Fanxia; Wang Yongxia; Liu Xiaoguang; Wang Rong

2010-01-01

Polyethersulfone(PES) microporous membrane was grafted with methacrylic acid under electron beam irradiation. Controlling the monomer concentration or the absorbed dose, the relationships of the degree of grafting with the monomer concentration and the absorbed dose were obtained for optimum the monomer concentration and absorbed dose. The grafted membrane was characterized by FT-IR and SEM, and the hydrophilicity contact angle of the membrane was tested. (authors)

PVDF multifilament yarns grafted with polystyrene induced by γ-irradiation: Influence of the grafting parameters on the mechanical properties

International Nuclear Information System (INIS)

Marmey, P.; Porte, M.C.; Baquey, Ch.

2003-01-01

The development of alternative prosthetic materials for cardiovascular applications has found growing interest due to the failure to date to be able to implement functional patent small diameter vascular grafts (diameter <5 mm). For instance, the successful implantation of small diameter polyester (PET) and expanded polytetrafluoroethylene (PTFEe) vascular grafts has not been achieved in humans. Our strategy is to work with a new multifilament yarns biomaterial, produced from polyvinylidene fluoride (PVDF), which shows suitable mechanical properties, such as a lower tensile modulus than PET and PTFEe. The required biological properties sought for (i.e. low thrombogenicity) could be achieved by 'heparin-like' surface modification treatments in order to modify the thrombogenicity levels of the polymeric materials [Ann. Biomed. Eng. 7 (1979) 429]. A four step method is necessary to achieve this 'heparin-like' surface transformation [J. Biomed. Mater. Res. 52 (2000) 119]. The first step consists in grafting polystyrene onto the PVDF surface by γ irradiation. The purpose of this study was to evaluate the influence of grafting parameters on the mechanical properties: (i) γ-ray irradiation time and (ii) grafting time of styrene monomers, which polymerize and form polystyrene bound to the PVDF surface

Graft copolymerization of N-vinyl-2-pyrrolidone onto pre-irradiated poly(vinylidene fluoride) powder

International Nuclear Information System (INIS)

Xu Chenqi; Huang Wei; Zhou Yongfeng; Yan Deyue; Chen Shutao; Huang Hua

2012-01-01

Graft copolymerization of N-vinyl-2-pyrrolidone (NVP) onto 60 Co γ-ray pre-irradiated poly (vinylidene fluoride) (PVDF) powder was investigated to find out the relationship between the degree of grafting (DG) and various factors, including monomer concentration, irradiation dose, reaction time, catalyst and so on. The DG can be calculated by comparing the amount of nitrogen element in the resulting copolymer (PVDF-g-PVP) powder with that in PVP on the basis of element analysis. The presence of PVP in the resulting PVDF powder was confirmed by the comparative studies of pristine PVDF and grafted PVDF powder through Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS), thermo gravimetric analyzer (TGA) and differential scanning calorimetry (DSC), respectively. When the reaction was performed at the monomer concentration of 20% (vol.) and the absorbed dose of 40 kGy for 3 h in water, the max. DG of 17.7% was obtained. - Highlights: ► We modify pristine PVDF powders with NVP by the pre-irradiated graft polymerization. ► The various factors influencing the degree of grafting are investigated in detail. ► The optimal condition of graft polymerization is obtained. ► The polymerization is processed at 20% (vol.) of NVP and 40kGy for 3 hours in water. ► The maximum degree of grafting is 17.7 % at such a condition.

Acrylamide graft over silicone rubber tubes by simultaneous irradiation in 60 Co source

International Nuclear Information System (INIS)

Julio, C.A.; Higa, O.Z.

1992-01-01

The synthesis of a hydrogel having silicone rubber tubes as support was carried out through the radiation grafting technique. The best conditions for the grafting development were determined in relation to the monomer and inhibitor concentration, dose rate and irradiation dose. The addition of cupric ions in the process inhibited the acrylamide homo polymerization and enhanced the grafting yield. The water content in the grafted tubes characterized the hydrophilic property of the material. (author)

Solvent and irradiation doses effects on the ion exchange capacity of sulfonated styrene grafted PVDF

International Nuclear Information System (INIS)

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

2011-01-01

Polymers exhibiting ion exchange capacity are studied for many years due to their application in several fields, such as membranes for proton exchange fuel cells, filtration membranes, heavy ions recovery and artificial muscles and sensors. Radiation induced grafting followed by sulfonation is a well-known way to obtain ion exchange polymers. Fluorinated polymers are frequently used as polymeric matrix for grafting due to their excellent physicochemical properties. Radiation induced grafting of styrene into poly (vinylidene fluoride) (PVDF) by simultaneous method in 1:1 styrene/toluene or styrene/N,N-dimethylformamide solutions was studied. Irradiations were performed under nitrogen atmosphere, room temperature and at doses of 5, 10 and 20 kGy with dose rate of 5 kGy.h -1 from a 60 Co gamma source. After washing, grafted materials were sulfonated in 10% chlorosulfonic acid/1,2-dichloroethane solutions for 4 h at room temperature. Characterization shows that increasing irradiation dose corresponds to increases in the grafting yield (GY %) gravimetrically calculated and these different solvents shows different grafting behaviors. Toluene allows no more than 3 % of grafting while DMF allows up to 55 % of grafting in the same condition. Grafting in toluene solution occurs on the surface and in DMF solution it occurs in the bulk, as confirmed by SEM. Both irradiation doses and solvent used have direct effects in the ion exchange capacities (calculated after titrations). FT-IR spectra exhibit new peaks after grafting and after sulfonation, attributed to grafted monomer and sulfonic groups attached to the styrene. DSC shows differences in thermal behavior of the polymer before and after each step. (author)

Solvent and irradiation doses effects on the ion exchange capacity of sulfonated styrene grafted PVDF

Energy Technology Data Exchange (ETDEWEB)

Ferreira, Henrique P.; Parra, Duclerc F.; Lugao, Ademar B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-07-01

Polymers exhibiting ion exchange capacity are studied for many years due to their application in several fields, such as membranes for proton exchange fuel cells, filtration membranes, heavy ions recovery and artificial muscles and sensors. Radiation induced grafting followed by sulfonation is a well-known way to obtain ion exchange polymers. Fluorinated polymers are frequently used as polymeric matrix for grafting due to their excellent physicochemical properties. Radiation induced grafting of styrene into poly (vinylidene fluoride) (PVDF) by simultaneous method in 1:1 styrene/toluene or styrene/N,N-dimethylformamide solutions was studied. Irradiations were performed under nitrogen atmosphere, room temperature and at doses of 5, 10 and 20 kGy with dose rate of 5 kGy.h{sup -1} from a {sup 60}Co gamma source. After washing, grafted materials were sulfonated in 10% chlorosulfonic acid/1,2-dichloroethane solutions for 4 h at room temperature. Characterization shows that increasing irradiation dose corresponds to increases in the grafting yield (GY %) gravimetrically calculated and these different solvents shows different grafting behaviors. Toluene allows no more than 3 % of grafting while DMF allows up to 55 % of grafting in the same condition. Grafting in toluene solution occurs on the surface and in DMF solution it occurs in the bulk, as confirmed by SEM. Both irradiation doses and solvent used have direct effects in the ion exchange capacities (calculated after titrations). FT-IR spectra exhibit new peaks after grafting and after sulfonation, attributed to grafted monomer and sulfonic groups attached to the styrene. DSC shows differences in thermal behavior of the polymer before and after each step. (author)

Brazilian status in blood irradiation in Graft-Versus-Host Disease (GVHD) prevention

International Nuclear Information System (INIS)

Goes, E.G. de; Borges, J.C.; Ghilardi Netto, T.

1996-01-01

A short overview of the Brazilian reality concerning Graft-Versus-Host Disease (GVHD) is presented. Suggestions of policies and procedures to optimise GVHD prevention are reported. A national irradiator device using cobalt teletherapy unit is proposed for irradiation of blood and cellular components

Synthesis of perm-selective membranes by grafting acrylic acid into air-irradiated Teflon-FEP films

Science.gov (United States)

Bozzi, Annick; Chapiro, Adolphe

Grafting acrylic acid into air-irradiated Teflon-FEP films was investigated. Pre-irradiation doses ranged from 0.5 to 10 kGy. Grafting occurred at 45 or 60°C. Homopolymerization inhibitors, ferrous ions or methylene blue, were added to the system. It was found that after completion of the reaction, within 40-100 min, membranes were obtained with very low electric resistivities. The influence of added inhibitors, pre-irradiation dose and grafting temperature was studied. From the results it is concluded that the initiating centers in air-irradiated Teflon-FEP are, on the one hand, peroxides of structure POOP', in which P is a polymeric radical and Pprime; a small fragment, and on the other trapped PO .2 radicals. The latter only react after losing their oxygen. In the presence of polymerization inhibitors, initiation involves a redox process which reduces the overall activation energy.

Synthesis of perm-selective membranes by grafting acrylic acid into air-irradiated Teflon-FEP films

International Nuclear Information System (INIS)

Bozzi, Annick; Chapiro, Adolphe

1988-01-01

Grafting acrylic acid into air-irradiated Teflon-FEP films was investigated. Pre-irradiation doses ranged from 0.5 to 10 kGy. Grafting occurred at 45 or 60 0 C. Homopolymerization inhibitors, ferrous ions or methylene blue, were added to the system. It was found that after completion of the reaction, within 40-100 min, membranes were obtained with very low electric resistivities. The influence of added inhibitors, pre-irradiation dose and grafting temperature was studied. From the results it is concluded that the initiating centers in air-irradiated Teflon-FEP are, on the one hand, peroxides of structure POOP', in which P is a polymeric radical and P' a small fragment, and on the other hand trapped PO 2 sup(·) radicals. The latter only react after losing their oxygen. In the presence of polymerization inhibitors, initiation involves a redox process which reduces the overall activation energy. (author)

A study of the behaviour of irradiated or unirradiated grafts in the camera aquosa of irradiated and unirradiated animals

International Nuclear Information System (INIS)

Djalali-Behzad, G.

1969-06-01

Following grafts of new born mice spinal ganglia in the 'camera aquosa' of adult mice, the authors tried hematopoietic tissue grafts in the same conditions. The growth of iso-logous and hetero-logous bone marrow in the 'camera aquosa' showed that this tissue, even after exposure to supralethal doses, was capable of survival and growth. A counter-experiment with non irradiated bone marrow grafts in the 'camera aquosa' of rats delivered 700 rads led to the conclusion that the environment, intoxicated by exposure, acted on the graft so that after vascularization it became unable to grow. (author) [fr

Grafting study of polysulfone polymeric membranes by gamma ray irradiation

International Nuclear Information System (INIS)

Furtado Filho, Acacio A.M.; Gomes, Ailton de S.

2011-01-01

Radiation-induced grafting of styrene poli sulfone films were investigated by simultaneous method in solution using gamma-ray from a radio nuclide 60 Co source. The gamma-ray energy of high intensity induced breaking of chemical bonds leading to free radical formation. The radical start a conventional polymerization sequence comparable with that obtained with a chemical catalyst acting as initiator. The effects of grafting conditions such as irradiation total dose, dose rate and addition of cross linking agent, were studied by means of morphology analysis, thermal degradation and crystallinity. After the grafting reaction, the membranes were submitted to an exhaustive extraction with solvent to remove the polystyrene homopolymer formed. The degree of grafting (DOG) was analyzed by percentage of weight increase. As a result, the reaction always follows the same pattern: DOG increases rapidly initially whilst propagation is the main reaction, then more slowly as termination becomes more frequent. (author)

Fetal hypothalamic transplants into brain irradiated rats: Graft morphometry and host behavioral responses

International Nuclear Information System (INIS)

Pearlman, S.H.; Rubin, P.; White, H.C.; Wiegand, S.J.; Gash, D.M.

1990-01-01

This study was designed to test the hypothesis that neural implants can ameliorate or prevent some of the long-term changes associated with CNS irradiation. Using a rat model, the initial study focused on establishing motor, regulatory, and morphological changes associated with brain radiation treatments. Secondly, fetal hypothalamic tissue grafts were placed into the third ventricle of rats which had been previously irradiated. Adult male Long Evans rats received one of three radiation doses (15, 22.5, ampersand 30 Gy) or no radiation. Three days after irradiation, 7 animals in each dose group received an embryonic day 17 hypothalamic graft into the third ventricle while the remaining 8-9 animals in each group received injections of vehicle solution (sham). Few changes were observed in the 15 and 22.5 Gy animals, however rats in the 30 Gy treatment group showed stereotypic and ambulatory behavioral hyperactivity 32 weeks after irradiation. Regulatory changes in the high dose group included decreased growth rate and decreased urine osmolalities, but these measures were extremely variable among animals. Morphological results demonstrated that 30 Gy irradiated animals showed extensive necrosis primarily in the fimbria, which extended into the internal capsule, optic nerve, hippocampus, and thalamus. Hemorrhages were found in the hippocampus, thalamus, and fimbria. Defects in the blood-brain barrier also were evident by entry of intravascularly injected horseradish peroxidase into the parenchyma of the brain. Animals in the 30 Gy grafted group showed fewer behavioral changes and less brain damage than their sham grafted counterparts. Specifically, activity measures were comparable to normal levels, and a dilute urine was not found in the 30 Gy implanted rats. Morphological changes support these behavioral results since only two 30 Gy implanted rats showed necrosis

Peroxydisulfate initiated synthesis of potato starch-graft-poly(acrylonitrile under microwave irradiation

Directory of Open Access Journals (Sweden)

2007-01-01

Full Text Available Potato starch-graft-poly(acrylonitrile could be efficiently synthesized using small concentration of ammonium peroxydisulfate (0.0014M in aqueous medium under microwave irradiation. A representative microwave synthesized graft copolymer was characterized using Fourier Transform Infrared Spectroscopy, X-ray Diffraction, Scanning Electron Microscopy and Thermogravimetric Analysis. Under microwave conditions oxygen removal from the reaction vessel was not required and the graft copolymer was obtained in high yield using very small amount of ammonium peroxydisulfate, however using the same amount of ammonium peroxydisulfate (0.0014M on thermostatic water bath no grafting was observed up to 98°C (even in inert atmosphere. Raising the concentration of the initiator to 0.24 M resulted into 10% grafting at 50 °C but in inert atmosphere.The viscosity/shear stability of the grafted starch (aqueous solution and water/saline retention ability of the microwave synthesized graft copolymer were also studied and compared with that of the native potato starch.

Hydrophilicity improvement of polyethersulfone powders by grafting acrylic acid with γ-ray simultaneous irradiation method

International Nuclear Information System (INIS)

Deng Bo; Hou Zhengchi; Zhang Fengying; Xie Leidong; Li Jing; Yang Haijun

2005-01-01

Acrylic acid was grafted to Polyethersulfone (PES) powders by liquid-phase simultaneous irradiation. Effects of grafting conditions, such as absorbed dose, volume fraction of monomer, inhibitor (Cu 2+ ) concentration, and pH of the grafting solution on degree of the grafting were investigated. Combined with gravimetric analysis, a working curve of grafting degree through FT-IR quantitative analysis was obtained. The highest grafting degree was achieved at dose of 25 kGy, volume fraction of monomer of 30% and inhibitor concentration of 0.004 mol/L. Greater degrees of the grafting could be obtained by adding increasing amount of hydrochloric acid to the system. Hydrophilicity of the grafted PES powders increased with higher degrees of the grafting. (authors)

Graft copolymerization of water soluble mixed monomers onto polyethylene by the pre-irradiation method

International Nuclear Information System (INIS)

Long Fu; Tang Liming; Zhao Jin; Gao Zhenyong

1993-01-01

Grafting of water soluble mixed monomers of acrylic acid (AA)/acrylamide (Am) and acrylic acid/methacrylic acid (MA) onto polyethylene film by the pre-irradiation grafting method was investigated. The results showed that the grafting proceeded successfully with the adding of ferric salt in the solution. In the case of AA/Am system, a synergistic effect was noticed. In the case of AA/MA system, the graft percent increased with the increase in the concentration of MA in the feed ratio. Furthermore, the effects of monomer concentration, radiation dose and temperature on the grafting were also studied

Graft polymerization of styrene onto starch by simultaneous cobalt-60 irradiation

International Nuclear Information System (INIS)

Fanta, G.F.; Burr, R.C.; Doane, W.M.; Russell, C.R.

1977-01-01

Starch-g-polystyrene copolymers have been prepared by the simultaneous 60 Co irradiation of starch--styrene mixtures, and copolymers have been characterized with respect to weight per cent polystyrene (% add-on) and also the molecular weight and molecular weight distribution of polystyrene grafts. In a typical polymerization, 4g each of starch and styrene were blended with 1 ml water and 1.5 ml of an organic solvent; the resulting semisolid paste was irradiated to a total dose of 1 Mrad. With ethylene glycol, acetonitrile, ethanol, methanol, acetone, and dimethylformamide as the organic solvent, values for % add-on ranged from 24% to 29%. The highest % add-on (43%) and the highest conversion of styrene to grafted polymer (76%) were obtained when the organic solvent was omitted, and water alone was used. When water was also omitted, polymerization of styrene was negligible; however, graft copolymer was formed in the absence of water when either ethylene glycol or ethanol was added. Attempts were unsuccessful to achieve a % add-on greater than 43% by doubling the amount of styrene in the polymerization recipe. Mixtures of equal weights of starch and styrene are relatively nonviscous, but these mixtures thicken when either water or ethylene glycol is blended in. Reasons for this thickening action and the possible influence of thickening on the graft polymerization reaction were explored

Modification of phase transitions in swift heavy ion irradiated and MMA-grafted ferroelectric fluoro-polymers

International Nuclear Information System (INIS)

Petersohn, E.; Betz, N.; Le Moel, A.

1994-01-01

Ferroelectric polyvinylidene fluoride (β) and copolymers of vinylidene fluoride trifluoroethylene (P(VDF/TrFE)) films were irradiated with swift heavy ions and post irradiation grafted with methyl methacrylate (MMA). We have studied the influence of irradiation parameters such as the ion fluence, the type of ion and the electronic stopping power, on the melting and crystallization temperatures and the ferroelectric-paraelectric phase transitions, by differential scanning calorimetry (DSC) and dielectric measurements. The relation between the shift in the transition temperatures and the ion fluence is described by a single term equation. Ion track grafting with MMA affects the ferroelectric-paraelectric phase transitions in P(VDF/TrFE) and leads to a strong amorphization of the polymer films. The grafting in β PVDF occurs mainly on the surface of the samples and no change in the transition temperatures is observed. (authors). 12 refs., 6 figs., 2 tabs

Stability of radicals in electron-irradiated fluoropolymer film for the preparation of graft copolymer fuel cell electrolyte membranes

DEFF Research Database (Denmark)

Larsen, Mikkel Juul; Ma, Yue; Qian, Huan

This presentation concerns the stability of radicals generated in poly(ethylene-alt-tetra­fluoro­ethylene) (ETFE) film by electron irradiation prior to grafting of styrene onto this base material. It has been demonstrated that the grafting yield decreases as the storage time of the irradiated fil...

Differential immune response of congenic mice to ultraviolet-treated major histocompatibility complex class II-incompatible skin grafts

International Nuclear Information System (INIS)

Vermeer, B.J.; Santerse, B.; Van De Kerckhove, B.A.; Schothorst, A.A.; Claas, F.H.

1988-01-01

The influence of ultraviolet (UVB) irradiation on the survival of H-2 class II-disparate skin grafts was studied in congenic mouse strains. Isolated skin was UVB irradiated in vitro at a dose of 40 mJ/cm 2 from both sides to remove Ia immunogenicity. Immediately after irradiation the skin was transplanted onto the flank of allogeneic mice. When B10.AQR grafts were transplanted onto B10.T(6R) recipients, a significant prolongation of the survival time was observed, while 50% of the UVB-treated grafts were not rejected at all. However, in the opposite direction--i.e., B10.T(6R) grafts onto B10.AQR recipients, no significant prolongation of the survival was observed. To test whether this effect was due to a difference in susceptibility of the donor skin to UVB irradiation or to a different immune response in the recipients, (B10.T(6R) x B10.AQR) grafts were transplanted onto the parent strains. Similar results were obtained, in that UVB-treated grafts did not show a prolonged survival in B10.AQR recipients, whereas a significant prolongation (50% of the grafts survived more than 100 days) was observed in B10.T(6R) recipients. UVB-treated (B10.T(6R) x B10.AQR)F1 grafts were also transplanted onto (B10.T(6R) x C57B1/10)F1, (B10.AQR x C57B1/10)F1, (B10.T(6R) x Balb/c)F1 and (B10.AQR x Balb/c)F1 recipients--but in none of these combinations was a prolonged survival time observed. These data suggest that, in contrast to all in vitro experiments, the abrogation of the immune response by UVB treatment of the stimulator cells is, in vivo, not a general phenomenon. The genetic constitution of the responder mice seems to play an important role in determining whether or not an immune response takes place

Post-irradiation time effects on the graft of poly(ethylene-alt-tetrafluoroethylene) (ETFE) films for ion exchange membrane application

Energy Technology Data Exchange (ETDEWEB)

Geraldes, Adriana N., E-mail: angeral@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Centro de Quimica e Meio Ambiente (CQMA), Av. Professor Lineu Prestes, 2242, 05508-900, Sao Paulo (Brazil); Zen, Heloisa A.; Ribeiro, Geise; Ferreira, Henrique P.; Souza, Camila P.; Parra, Duclerc F.; Santiago, Elisabete I.; Lugao, Ademar B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Centro de Quimica e Meio Ambiente (CQMA), Av. Professor Lineu Prestes, 2242, 05508-900, Sao Paulo (Brazil)

2010-03-15

Grafting of styrene followed by sulfonation onto poly(ethylene-alt-tetrafluoroethylene) (ETFE) was studied for synthesis of ion exchange membranes. Radiation-induced grafting of styrene onto ETFE films was investigated after simultaneous irradiation (in post-irradiation condition) using a {sup 60}Co source. The ETFE films were irradiated at 20 kGy dose at room temperature and chemical changes were monitored after contact with styrene for grafting. The post-irradiation time was established at 14 days when the films were remained in styrene/toluene 1:1 v/v. After this period the grafting degree was evaluated in the samples. The grafted films were sulfonated using chlorosulfonic acid and 1, 2-dichloroethane 20:80 (v/v) at room temperature for 5 h. The membranes were analyzed by infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), thermogravimetric measurements (TG) and degree of grafting (DOG). The ion exchange capacity (IEC) of membranes was determined by acid-base titration and the values for ETFE membranes were achieved higher than Nafion films. Preliminary single cell performance was made using pure H{sub 2} and O{sub 2} as reactants at a cell temperature of 80 deg. C and atmospheric gas pressure. The fuel cell performance of ETFE films was satisfactory when compared to state-of-art Nafion membranes.

Post-irradiation time effects on the graft of poly(ethylene-alt-tetrafluoroethylene) (ETFE) films for ion exchange membrane application

Science.gov (United States)

Geraldes, Adriana N.; Zen, Heloísa A.; Ribeiro, Geise; Ferreira, Henrique P.; Souza, Camila P.; Parra, Duclerc F.; Santiago, Elisabete I.; Lugão, Ademar B.

2010-03-01

Grafting of styrene followed by sulfonation onto poly(ethylene-alt-tetrafluoroethylene) (ETFE) was studied for synthesis of ion exchange membranes. Radiation-induced grafting of styrene onto ETFE films was investigated after simultaneous irradiation (in post-irradiation condition) using a 60Co source. The ETFE films were irradiated at 20 kGy dose at room temperature and chemical changes were monitored after contact with styrene for grafting. The post-irradiation time was established at 14 days when the films were remained in styrene/toluene 1:1 v/v. After this period the grafting degree was evaluated in the samples. The grafted films were sulfonated using chlorosulfonic acid and 1, 2-dichloroethane 20:80 (v/v) at room temperature for 5 h. The membranes were analyzed by infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), thermogravimetric measurements (TG) and degree of grafting (DOG). The ion exchange capacity (IEC) of membranes was determined by acid-base titration and the values for ETFE membranes were achieved higher than Nafion ® films. Preliminary single cell performance was made using pure H 2 and O 2 as reactants at a cell temperature of 80 °C and atmospheric gas pressure. The fuel cell performance of ETFE films was satisfactory when compared to state-of-art Nafion ® membranes.

Graft copolymerization of N-maleoyl-N-phthaloyl-chitosan (MAPHCS) and acrylic acid via γ-ray irradiation

International Nuclear Information System (INIS)

Mu Qing; Fang Yue'e

2006-01-01

Chitosan is a well-known abundant natural polymer with good biodegradability, biocompatibility and bioactivity. But its insolubility in common organic solvents of chitosan have hindered its utilization and basic research. N-maleoyl-N-phthaloyl-chitosan (MAPHCS), soluble in DMF or DMSO, was synthesized and characterized by Fourier transform infrared spectra analysis (FT-IR) and 1 H-NMR. The graft copolymerization of acrylic acid onto chitosan was carried out with N-maleoyl-N-phthaloyl-chitosan as intermediate in homogeneous system and initiated by γ-irradiation. The double bond of MAPHCS may be the grafting site because the grafting field was much higher than that of the graft copolymerization of acrylic acid and phthaloylchitosan via γ-ray irradiation. The chemical structure of the graft copolymer was characterized by FT-IR and 1 H-NMR. As indicated in FTIR spectra, the evidence of the stronger absorbance at 2800-3000 cm -1 for C-H and at 1720 cm -1 for carboxyl group implied significantly the successful introduction of the poly (acrylic acid) on the chitosan chain. Differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) were also used to characterize the copolymer. Effects of synthesis variables on the graft copolymerization were studied in light of the grafting percentage. The grafting percentage increased with the dose at lower doses, and then decreased. The maximum grafting percentage was up to 132%. (authors)

Can low-dose irradiation of donor hearts before transplantation inhibit graft vasculopathy?

International Nuclear Information System (INIS)

Shirasawa, Bungo; Hamano, Kimikazu; Ito, Hiroshi; Gohra, Hidenori; Katho, Tomoe; Fujimura, Yoshihiko; Esato, Kensuke

1999-01-01

This experimental study was conducted to histopathologically determine whether the low-dose irradiation of donor hearts before transplantation can inhibit graft vasculopathy. Immediately after donor F 344 rat hearts were removed, they were treated with a single dose of radiation using 7.5 Gy, 15 Gy, or no radiation (control group). The F 344 hearts were transplanted into Lewis rats heterotopically, and cyclosporine A was injected intramuscularly for 20 days after transplantation in all groups. The hearts were harvested 90 days after transplantation, and examined for intimal thickening using elastica van Gieson staining. Severe intimal thickening was observed in both the irradiated groups, the percent intimal area of the coronary arteries was significantly increased in both these groups, to 34.3±12.9 in the 7.5 Gy group and 37.0±8.9 in the 15 Gy group, compared with 23.1±9.8 in the control group (p<0.01). In conclusion, these findings show that low-dose irradiation to donor hearts before transplantation does not inhibit graft vasculopathy. (author)

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

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.

Management of an irradiated anophthalmic socket following dermis-fat graft rejection: A case report

Directory of Open Access Journals (Sweden)

Raizada Kuldeep

2008-01-01

Full Text Available Dermis-fat graft (DFG is often the only promising option in cases of severely contracted sockets. However, there is an increased risk of graft failure in irradiated sockets with decreased vascularity. In such difficult cases, repeat DFG implantation also has higher risks of graft failure. We describe an ingenious method of successful management of an irradiated anophthalmic socket following DFG infection and necrosis, with acceptable cosmetic results. At surgery, an orbital impression was taken with ophthalmic grade alginate. Based on this measurement, a custom-made stem pressure socket-expander made up of high density polymethyl methacrylate (PMMA was fitted, a week post surgery and kept in situ for six weeks. On review, the fornices had considerably deepened. The expander device was removed and the patient was now fitted with a custom-made thicker prosthesis made up of high-density PMMA. The patient has followed up for a year subsequently and the prosthesis has remained stable.

Irradiation grafting of natural rubber latex with maleic anhydride and its compatibilization of poly(lactic acid)/natural rubber blends

Science.gov (United States)

Pongsathit, Siriwan; Pattamaprom, Cattaleeya

2018-03-01

Maleic anhydride (MA) is an interesting monomer to be grafted onto natural rubber(NR) due to its potential as a compatibilizer of hydrophobic rubbers and polymers with higher polarity. So far, radiation grafting of MA onto NR in latex state has not been reported. In this study, the grafting of NR with MA in latex state was investigated by exposing the latex to cobalt-60 gamma irradiation at a fixed MA content of 9% and a varied absorbed doses from 2 to 10 kGy. The FTIR spectrometer, 1H NMR spectrometer and gel content analysis have confirmed successful grafting of MA onto NR after irradiation. The grafted NRs were then used to increase the compatibility and the impact property of PLA/NR blends. It was found that the highest impact strength of the blends was achieved when the grafting was carried out at the absorbed dose of 4 kGy.

Analysis of Gel Permeation Chromatography From Irradiation Copolymer Grafting of Methylmethacrylate on to Natural Rubber

International Nuclear Information System (INIS)

Hendrana, Sunit; Purwanto, Indratmoko Hari; Karyaningsih, Ipit; Utama, MargaHerwinarni

2004-01-01

Grafting of methyl methacrylate (MMA) onto natural rubber was carried out by γ-irradiation using 60 Co source at dose rate 1 KGy/h and total dose of 5 KGy. Gel permeation chromatography (GPC) was used to analyse the grafting. The GPC's chromatogram, molecular weight and molecular weight distribution data indicate that grafting of MMA onto natural rubber and homo polymerization of MMA are the reaction mostly occurs. Meanwhile, the presence of natural rubber radical with a chain end natural rubber radical affect the PMMA homopolymer occurred

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.

Graft copolymerization of vinyl monomers onto nylon 6 fibers by γ-ray pre-irradiation in air

International Nuclear Information System (INIS)

Iwasaki, Tatsuo; Ueda, Yoshitsugu

1992-01-01

Vinyl acetate, methyl methacrylate, alkyl acrylates, acrylonitrile, and acrylamide, were grafted onto nylon 6 fibers by the γ-ray pre-irradiation technique, and the effects of grafting on the microstructure and the mechanical properties of the graft copolymers were investigated. According to the analysis by wide-angle X-ray diffraction, the degree of crystallization decreased by increasing the percent graft of poly(vinyl acetate) in the grafted nylon 6 films. The mechanical parameters, such as the Young's modulus and the tensile strength at break, increased with increasing percent graft up to 50%. When percent grafting was smaller than 50%, rather homogeneous amorphous materials were obtained with vinyl acetate, while heterogeneous ones were obtained with other vinyl monomers. A poly(vinyl alcohol) grafted nylon 6 was obtained effectively by saponification of poly(vinyl acetate) grafted nylon 6, the former showing higher mechanical properties than the latter. Similar behavior was observed after saponification of the poly(methyl acrylate) grafted nylon 6. (author)

Synthesis of Fuel Cell Membrane: Copolymerization of Styrene on ETFE Film by Grafted pre-Irradiation

Directory of Open Access Journals (Sweden)

Yohan Yohan

2010-10-01

Full Text Available Preirradiation Grafting styrene monomer on ETFE  film has been prepared. Research has been  performed by γ-ray radiation at various total dose from 2.5 - 12.5 kGy and various dose rate from 1.3 - 1.9 kGy/hour. Irradiated copolymer is then grafted by styrene monomer in various solvent: ethanol, 2-propanol, and toluene, various concentration from 20 - 70% volume, various temperature from 50 - 90oC, and various grafting time from 2 - 12 hours. The results showed that percent of grafting is increase with increase of total dose and decrease of  rate dose. The optimum experiment conditions are obtained at total dose 10 kGy, dose rate 1,9 kGy/hour, 2-propanol solvent, 40% volume styrene, 4 hours grafting time, and 70oC grafting temperature.

Mutual irradiation grafting on indigenous aramid fiber-3 in diethanolamine and epichlorohydrin and its effect on interfacially reinforced epoxy composite

Energy Technology Data Exchange (ETDEWEB)

Xing, Lixin [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001,China (China); Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Liu, Li, E-mail: liuli@hit.edu.cn [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001,China (China); Xie, Fei [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001,China (China); Huang, Yudong [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001,China (China); State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150001 (China)

2016-07-01

Highlights: • High energy gamma rays were used to decorate the surface of aramid fiber via mutual irradiation grafting process in two medium. • The effects of different grafting medium on aramid fiber surface were investigated through SEM, AFM, XPS, wettability and adsorption measurements. • Interfacial properties of aramid reinforced polymer composites were remarkable improved after mutual irradiation. - Abstract: The surface of indigenous aramid fiber-3 (IAF3) was decorated via mutual irradiation grafting process in diethanolamine (DEA) and epichlorohydrin (ECH), respectively, with the assist of high energy gamma rays. This modification method with great permeability produced the homogeneous and ameliorative AF3 surfaces, which were observed by the scanning electron microscopy (SEM) and atom forced microscopy (AFM). Enhanced surface free energy and reduced contact angles of irradiated AF3 verified the fabulous effectiveness of mutual irradiation without seriously injured tensile strength. The composites based on epoxy resin (ER) polymer as the matrix and irradiated IAF3 grafted DEA and ECH as the reinforcement. By capitalizing on the irradiated IAF3 which has higher wettability and adsorption on resin, the irradiated IAF3-ECH/ER composites exhibit admirable interfacial mechanical performance as compared to the pristine IAF3 contained composites. The interfacial shear strength (IFSS), interlaminar shear strength (ILSS) and flexural strength of composites were remarkable improved to 86.5, 60.13 and 511 MPa respectively, from the pristine IAF3/ER composite with IFSS of 65.9 MPa, ILSS of 48.1 MPa, and flexural strength of 479 MPa.

Mutual irradiation grafting on indigenous aramid fiber-3 in diethanolamine and epichlorohydrin and its effect on interfacially reinforced epoxy composite

International Nuclear Information System (INIS)

Xing, Lixin; Liu, Li; Xie, Fei; Huang, Yudong

2016-01-01

Highlights: • High energy gamma rays were used to decorate the surface of aramid fiber via mutual irradiation grafting process in two medium. • The effects of different grafting medium on aramid fiber surface were investigated through SEM, AFM, XPS, wettability and adsorption measurements. • Interfacial properties of aramid reinforced polymer composites were remarkable improved after mutual irradiation. - Abstract: The surface of indigenous aramid fiber-3 (IAF3) was decorated via mutual irradiation grafting process in diethanolamine (DEA) and epichlorohydrin (ECH), respectively, with the assist of high energy gamma rays. This modification method with great permeability produced the homogeneous and ameliorative AF3 surfaces, which were observed by the scanning electron microscopy (SEM) and atom forced microscopy (AFM). Enhanced surface free energy and reduced contact angles of irradiated AF3 verified the fabulous effectiveness of mutual irradiation without seriously injured tensile strength. The composites based on epoxy resin (ER) polymer as the matrix and irradiated IAF3 grafted DEA and ECH as the reinforcement. By capitalizing on the irradiated IAF3 which has higher wettability and adsorption on resin, the irradiated IAF3-ECH/ER composites exhibit admirable interfacial mechanical performance as compared to the pristine IAF3 contained composites. The interfacial shear strength (IFSS), interlaminar shear strength (ILSS) and flexural strength of composites were remarkable improved to 86.5, 60.13 and 511 MPa respectively, from the pristine IAF3/ER composite with IFSS of 65.9 MPa, ILSS of 48.1 MPa, and flexural strength of 479 MPa.

Autologous fat graft in irradiated orbit postenucleation for retinoblastoma.

Science.gov (United States)

Klinger, Francesco; Maione, Luca; Vinci, Valeriano; Lisa, Andrea; Barbera, Federico; Balia, Laura; Caviggioli, Fabio; Di Maria, Alessandra

2018-01-05

Autologous fat grafting has been extensively and successfully adopted in a number of pathologic conditions in regenerative surgery especially on irradiated fields in order to improve pain symptoms and tissue trophism promoting scar release. In the present study, we report our experience with autologous fat grafting for the treatment of postirradiation fibrosis and pain on three consecutive patients undergoing orbital enucleation for locally advanced retinoblastoma (RB) and subsequent radiotherapy. We selected three consecutive patients who underwent orbital enucleation for locally advanced RB and subsequent local radiotherapy showing severe reduction in orbital volume and eyelid length and retraction due to fibrosis, spontaneous local pain exacerbated after digital pressure with no possibility to place an ocular implant. They underwent autologous fat grafting in the orbital cavity and results were evaluated by clinical examination at 5 and 14 days, and 1, 3, 6 months, and 1 year after surgery. A significant release of scar retraction, reduction of fibrosis and orbital rim contraction together with an important improvement of pain symptoms was observed in all patients. The local changes observed enabled an ease placement of an ocular prosthetic implant (implant). No local or systemic complication occurred. Fat grafting is a promising treatment for patients showing radiotherapy related complication in the orbital area and it should be adopted by all oculoplastic surgeon in order to improve pain syndrome creating the ideal local conditions for the placement of an ocular prosthetic implant.

Gamma irradiation effects on the grafting of low-density polyethylene with diethyl maleate

International Nuclear Information System (INIS)

Sanchez, Y.; Albano, C.; Karam, A.; Perera, R.; Silva, P.; Gonzalez, J.

2005-01-01

In this work, a low-density polyethylene (LDPE) was grafted with diethyl maleate (DEM) using gamma-rays from a Cobalt-60 source at different absorbed doses and monomer concentrations between 5 and 30 wt.%. This process was carried out in a decalin solution at 10 w/v% to obtain a homogeneous dispersion of the monomer into the polyethylene matrix. It was found that the grafting degree increases with the absorbed doses, as a consequence of the increased amount of energy given to the system, which made the grafting process more favorable. The grafting degree also increases with the concentration of DEM, because a higher concentration makes the insertion easier due to the increased availability of the free monomer. The highest grafting degree was obtained at 200 kGy of absorbed dose and with 30 wt.% of DEM. The melt flow index (MFI) values showed a decreasing trend as the absorbed dose was increased. This fact reveals that crosslinking and grafting are taking place simultaneously, this behavior being remarkable at higher irradiation doses. The results from thermogravimetric analysis (TGA) showed that the initial degradation temperatures remained almost unchanged with the absorbed dose

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)

The use of irradiated corneal patch grafts in pediatric Ahmed drainage implant surgery.

Science.gov (United States)

Nolan, Kaitlyn Wallace; Lucas, Jordyn; Abbasian, Javaneh

2015-10-01

To describe the use of irradiated cornea for scleral reinforcement in Ahmed glaucoma valve drainage implant (AGV) devices in children. The medical records of patients endophthalmitis, and tube/plate self-explantation. A total of 25 procedures (20 patients) met inclusion criteria. Average patient age was 70 months (range, 2 months to 17 years). Mean follow-up was 24.8 months (range, 6 months to 6.2 years). One tube experienced conjunctival exposure through two separate corneal grafts (2/25 cases [8%]), sequentially in the same eye. The first event occurred at month 3.5 after primary implantation of the tube shunt; the second erosion occurred following revision of the existing implant at month 1.5 postoperatively. There were 2 cases of auto-explantation, 2 cases of wound dehiscence, and 1 case of persistent inflammation. There were no cases of endophthalmitis or other infections. To our knowledge, this is the first report describing the use of corneal patch grafts in children. Irradiated cornea improves cosmesis and enhances visualization of the tube. The risk of tube exposure was found to be low and comparable to other materials used as a patch graft. Copyright © 2015 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

In vitro hemocompatibility of sulfonated polypropylene non-woven fabric prepared via a facile γ-ray pre-irradiation grafting method

Energy Technology Data Exchange (ETDEWEB)

Li, Rong [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Wu, Guozhong [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031 (China); Ye, Yin, E-mail: yeyin@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)

2015-11-30

Graphical abstract: - Highlights: • Sulfonated PP{sub NWF} was successfully fabricated via γ-ray pre-irradiation-induced graft polymerization of SSS method with the aid of AAm. • Compared with the pristine PP{sub NWF}, the sulfonated PP{sub NWF} material presented outstanding hydrophilicity. • The sulfonated PP{sub NWF} exhibited good hemocompatibility. - Abstract: Sulfonated polypropylene non-woven fabric (PP{sub NWF}) was successfully prepared via γ-ray pre-irradiation-induced graft polymerization of sodium styrenesulfonate (SSS) and acrylamide (AAm). The effect of pre-irradiation dose, reaction temperature, reaction time and concentration of binary monomer on the degree of grafting (DG) was studied. The chemical structure of the original and modified PP{sub NWF} materials were investigated by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) to confirm the successful introduction of sulfonated (−SO{sub 3}{sup −}) group. The wettability was examined via measurement of de-ionized water adsorption percentage, which demonstrated that the hydrophilicity of PP{sub NWF} was greatly enhanced after graft modification. A little amount of bovine serum albumin (BSA) adsorption and nearly no platelet adhesion on the surface of modified PP{sub NWF} and low hemolytic ratio of the modified PP{sub NWF} revealed that the sulfonated PP{sub NWF} exhibited good hemocompatibility. Besides, blood clotting time measurement indicated that the anticoagulant property of PP{sub NWF} was effectively enhanced via SSS modification. Consequently, the hydrophilicity, in vitro hemocompatibility and anticoagulant effect of PP{sub NWF} were significantly improved by γ-ray pre-irradiation-induced graft polymerization of SSS.

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

Gas-phase and liquid-phase pre-irradiation grafting of AAc onto LDPE and HDPE films for pervaporation membranes

International Nuclear Information System (INIS)

Rao Zhigong; Li Guixiang; Sugo, Takanobu; Okamoto, Jiro

1992-01-01

A study has been made on gas-phase and liquid-phase pre-irradiation grafting of acrylic acid onto LDPE and HDPE films for pervaporation membranes of ethanol-water mixtures. It was found that the degree of grafting, percent volume change of grafted membranes and length of grafting chains depend on the methods of grafting, crystal state of substrate films and diffusion rate of the monomer in the films. The pervaporation characteristics of grafted membranes is influenced directly by the surface hydrophilicity of grafted membranes, temperature of the feed, degree of grafting, crosslinking of grafted chains and alkaline metal ions in the functional groups. The potassium ion exchange membrane of HDPE synthesized by gas-phase grafting has better pervaporation efficiency. At 80 wt% ethanol in the feed, 25 o C feed temperature and 70% degree of grafting a grafted membrane has a 0.65 kg/m 2 h flux and a separation factor of 20. (Author)

Graft polymerization of guar gum with acryl amide irradiated by microwaves for colonic drug delivery.

Science.gov (United States)

Shahid, Muhammad; Bukhari, Shazia Anwer; Gul, Yousra; Munir, Hira; Anjum, Fozia; Zuber, Mohammad; Jamil, Tahir; Zia, Khalid Mahmood

2013-11-01

This article is aimed to discuss the modification of guar gum through microwave irradiation by varying the time of irradiation. The characterization of the modified products was carried out using FTIR spectroscopic analysis. The FT-IR spectrum of the pure guar gum (GG) sample showed a broad peak at 3298 cm(-1) while the modified GG sample displayed a peak at 1541 cm(-1) which was absent in the crude sample. The X-ray diffraction (XRD) analysis confirmed the increase in crystallinity due to grafting of the sample with polyacrylamide (GG-g-PAM). Scanning electron microscope (SEM) images revealed that granular form of guar gum was changed into fibrillar structure after grafting. Thermo-gravimetric analysis of the modified samples was also carried out and discussed. The role of guar gum as a matrix for controlled release of drug triamcinolone was evaluated. The GG-acrylamide grafted samples presented a correlation between drug release and time of microwave exposure. The results revealed that such modified product has potential applications in colonic drug delivery system. Copyright © 2013 Elsevier B.V. All rights reserved.

A study of the behaviour of irradiated or unirradiated grafts in the camera aquosa of irradiated and unirradiated animals; Etude du comportement d'un greffon irradie ou non, transplante dans la chambre anterieure de l'oeil d'un animal irradie ou non

Energy Technology Data Exchange (ETDEWEB)

Djalali-Behzad, G [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1969-06-01

Following grafts of new born mice spinal ganglia in the 'camera aquosa' of adult mice, the authors tried hematopoietic tissue grafts in the same conditions. The growth of iso-logous and hetero-logous bone marrow in the 'camera aquosa' showed that this tissue, even after exposure to supralethal doses, was capable of survival and growth. A counter-experiment with non irradiated bone marrow grafts in the 'camera aquosa' of rats delivered 700 rads led to the conclusion that the environment, intoxicated by exposure, acted on the graft so that after vascularization it became unable to grow. (author) [French] Apres avoir greffe des ganglions rachidiens de souriceaux nouveaux-nes dans la chambre anterieure de l'oeil de souris adultes, l'auteur a tente de greffer du tissu hematopoietique de la meme facon. La proliferation de la moelle osseuse isologue et heterologue, dans la chambre anterieure de l'oeil, lui a permis de mettre en evidence une certaine capacite de survie et de proliferation de ce tissu irradie meme a dose supraletale. Par une contre-experimentation, c'est-a-dire par la greffe de moelle non irradiee dans la chambre anterieure de rats irradies a 700 rads, il conclut que le milieu ambiant, intoxique par l'irradiation, agit sur le greffon de telle sorte que ce dernier, apres s'etre vascularise, devient depourvu de son aptitude de proliferation. (auteur)

Fabrication of thermo-responsive PNIPAAm-g-ETFE for cell culture dishes by pre-irradiation grafting

Science.gov (United States)

Yamahara, Yumi; Nagasawa, Naotsugu; Taguchi, Mitsumasa; Oshima, Akihiro; Washio, Masakazu

2018-01-01

Thermo-responsive templates for the cell cultivation based on Poly(tetrafluoroethylene-co-ethylene) (ETFE) were fabricated by pre-irradiation grafting of N-isoproplyacrylamide (NIPAAm) monomer by electron beam (EB) irradiation under nitrogen gas atmosphere at room temperature, and their characteristic properties were studied. The detachment of cultured HeLa cells from fabricated thermo-responsive templates were attempted. Furthermore, the reaction mechanism is proposed using ESR spectroscopy and FT-IR spectroscopy. It is confirmed that the cultured HeLa cells were detached from fabricated thermo-responsive templates at 20 °C. Water contact angle analysis indicated that obtained templates had thermo-response around 30 °C. It is suggested that the grafted polymer chains would mainly react with peroxy radicals (-CF2-CF(OO･)-) on tetrafluoroethylene unit in ETFE.

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.

Microfiltration membranes prepared from polyethersulfone powder grafted with acrylic acid by simultaneous irradiation and their pH dependence

International Nuclear Information System (INIS)

Deng Bo; Li Jingye; Hou Zhengchi; Yao Side; Shi Liuqing; Liang Guoming; Sheng Kanglong

2008-01-01

Polyethersulfone (PES) powder was grafted with acrylic acid (AAc) by simultaneous γ-ray irradiation. The kinetics of the radiation induced graft polymerization was studied and the grafted PES powder was characterized. Then, microfiltration (MF) membranes were prepared from PES-g-PAAc powder with different degrees of grafting (DG) under phase inversion method. The swelling behavior and the mean pore size of MF membranes were measured, and the filtration property was tested. The results showed that the pore size and the flux of MF membranes increased with the increase in DG. And, MF membranes' properties were dependent on the pH value

Effects of grafts of single anterior pituitary glands on the incidence and type of mammary neoplasm in neutron- or γ-irradiated Fischer female rats

International Nuclear Information System (INIS)

Clifton, K.H.; Douple, E.B.; Sridharan, B.N.

1976-01-01

Three batches comprised of 48 young adult Fischer female rats each were subjected to total-body irradiation with 50 rads modified fission neutrons, or were given 600 rads 137 Cs γ-rays, or served as unirradiated controls. On the day following exposure, one-half of each batch was grafted with a single anterior pituitary gland beneath the left kidney capsule. The animals were observed for mammary neoplasia and all those that died during the experiment were autopsied. The experiment was terminated 538 +- 13 days after irradiation when all neutron-irradiated, pituitary-grafted animals had one or more mammary tumors. Only 2 of the 23 untreated rats that survived until termination of the experiment developed mammary fibroadenomas, and none had mammary carcinomas. The incidence of fibroadenomas was increased, and a single carcinoma was found in unirradiated rats with pituitary grafts. Irradiation alone caused an increase in the incidence of mammary fibroadenomas and the appearance of carcinomas. Fibroadenomas were markedly increased by the addition of pituitary grafts to irradiation. Carcinoma incidence was less markedly affected. The neutron dose of 50 rads was slightly more effective in inducing mammary neoplasms than the 600-rad dose of γ-rays

The morphological effect of electron irradiation on the healing of skin wounds and skin grafts in the rat

International Nuclear Information System (INIS)

Wang, Q.

1995-01-01

Current oncological practice frequently uses pre-, intra- or post-operative radiotherapy/chemotherapy. Before such treatment can begin it is imperative to establish that satisfactory wound healing will occur. Many previous studies have examined the response of wound healing to ionizing and non-ionizing radiation. In general, clinical and experimental reports indicate that ionizing radiation produces poor to difficult healing of wounds, and can even prevent healing altogether. It is for this reason that the effect of radiation on wound repair has been a long standing concern for surgeons, radiotherapists and radiobiologists. Electron irradiation produces large differences in depth-dose distributions. This enables the delivery of a constant maximal dose throughout the superficial layer of tissue, for example, the total depth of skin, with less damage in deeper tissue layers, compared to that produced by the use of electromagnetic radiation such as X-rays. It is for this reason that electron beam irradiation has been selected as a radiation source for radiation of the graft bed. To date there have been few morphological examinations of the effect of electron radiation on the healing of skin wounds in rats. A review of the literature shows no information on the use of radiation of the graft bed in skin graft surgery. In the present work the processes involved in wound repair in response to radiation were studied, morphologically, using two experimental models, incisional wounds combined with pre-operative radiation and skin autografts combined with radiation of the wound bed. In the latter case an unirradiated skin graft was surgically attached to an irradiated wound bed. Light microscopy (LM), backscattered electron imaging (BEI), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used as investigative tools. These repair processes include inflammation, re-epithelialization, re-formation of the dermo-epidermal junction, re

The morphological effect of electron irradiation on the healing of skin wounds and skin grafts in the rat

Energy Technology Data Exchange (ETDEWEB)

Wang, Q

1995-07-01

Current oncological practice frequently uses pre-, intra- or post-operative radiotherapy/chemotherapy. Before such treatment can begin it is imperative to establish that satisfactory wound healing will occur. Many previous studies have examined the response of wound healing to ionizing and non-ionizing radiation. In general, clinical and experimental reports indicate that ionizing radiation produces poor to difficult healing of wounds, and can even prevent healing altogether. It is for this reason that the effect of radiation on wound repair has been a long standing concern for surgeons, radiotherapists and radiobiologists. Electron irradiation produces large differences in depth-dose distributions. This enables the delivery of a constant maximal dose throughout the superficial layer of tissue, for example, the total depth of skin, with less damage in deeper tissue layers, compared to that produced by the use of electromagnetic radiation such as X-rays. It is for this reason that electron beam irradiation has been selected as a radiation source for radiation of the graft bed. To date there have been few morphological examinations of the effect of electron radiation on the healing of skin wounds in rats. A review of the literature shows no information on the use of radiation of the graft bed in skin graft surgery. In the present work the processes involved in wound repair in response to radiation were studied, morphologically, using two experimental models, incisional wounds combined with pre-operative radiation and skin autografts combined with radiation of the wound bed. In the latter case an unirradiated skin graft was surgically attached to an irradiated wound bed. Light microscopy (LM), backscattered electron imaging (BEI), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used as investigative tools. These repair processes include inflammation, re-epithelialization, re-formation of the dermo-epidermal junction, re

Low-dose ultraviolet-B irradiation of donor corneal endothelium and graft survival

International Nuclear Information System (INIS)

Dana, M.R.; Olkowski, S.T.; Ahmadian, H.; Stark, W.J.; Young, E.M.

1990-01-01

Donor rabbit corneal endothelium was pretreated with different doses of ultraviolet (UV-B) irradiation (302 nm) before grafting to test whether allograft survival could be favorably affected in comparison with untreated corneas grafted into the same recipients. Endothelial rejection was observed in 19 of 32 (59%) eyes that received no treatment compared with five of 32 (16%) eyes that received UV-B (P less than 0.001), and increasing doses of UV-B were associated with lower rejection rates (P less than 0.05). Although exposure of donor endothelium significantly reduced endothelial rejection at all doses tested, it resulted in primary graft failure in a substantial proportion of corneas treated at high doses. Class II (Ia) antigen staining of corneal tissue was present in conjunction with clinical evidence of rejection, and the magnitude of staining correlated with the histologic extent of inflammation. Scanning electron microscopy revealed various endothelial cell surface irregularities and membrane defects in high-dose UV-treated corneas. Endothelial cell cultures exposed in vitro to UV-B light showed a dose-dependent loss in cell viability. These data suggest that UV-B pretreatment of donor corneal endothelium prolongs graft survival but that toxic side effects must be carefully controlled

Polymer electrolyte membranes for fuel cells by radiation induced grafting with electron beam irradiation: state-of-the-art

International Nuclear Information System (INIS)

Nasef, M.M.; Nasef, M.M.

2010-01-01

Polymer electrolyte membranes have generated considerable interest in various fields of industrial interest due to their wide spread applications in fuel cells, batteries, electrolyzers sensors and actuators. Such diversity in applications implies a strong demand to architect the membranes towards particular properties for specific applications. Radiation induced grafting of vinyl and acrylic monomers into polymeric films, is an appealing method for producing various polymer electrolyte membranes. This method has the advantages of simplicity, controllability over the composition leading to tailored membrane properties and absence of shaping problem as preparation starts with substrate in a film form. It also has the flexibility of using various types of radiation sources such as gamma-rays and electron beam. Of all, electron beam (EB) accelerator is an advantageous source of high energy radiation that can initiate grafting reactions required for preparation of the membranes particularly when pilot scale production and commercial applications are sought. The grafting penetration can be varied from surface to bulk of membranes depending on the acceleration energy. This lecture reviews the-state of- the-art in the use of EB irradiation in preparation of composite and grafted polymer electrolyte membranes for fuel cell applications by radiation induced grafting with simultaneous irradiation and preirradiation methods. The use of simultaneous EB irradiation method was found to simplify the process and reduce the reaction time as well as the monomer consumption whereas the use of preirradiation method in a single-step route provides a shorter route to prepare polymer electrolyte membranes with improved properties and reduced cost in addition of setting basis for designing a continuous line to produce these membranes with dedicated EB facilities

A study of the behaviour of irradiated or unirradiated grafts in the camera aquosa of irradiated and unirradiated animals; Etude du comportement d'un greffon irradie ou non, transplante dans la chambre anterieure de l'oeil d'un animal irradie ou non

Energy Technology Data Exchange (ETDEWEB)

Djalali-Behzad, G. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1969-06-01

Following grafts of new born mice spinal ganglia in the 'camera aquosa' of adult mice, the authors tried hematopoietic tissue grafts in the same conditions. The growth of iso-logous and hetero-logous bone marrow in the 'camera aquosa' showed that this tissue, even after exposure to supralethal doses, was capable of survival and growth. A counter-experiment with non irradiated bone marrow grafts in the 'camera aquosa' of rats delivered 700 rads led to the conclusion that the environment, intoxicated by exposure, acted on the graft so that after vascularization it became unable to grow. (author) [French] Apres avoir greffe des ganglions rachidiens de souriceaux nouveaux-nes dans la chambre anterieure de l'oeil de souris adultes, l'auteur a tente de greffer du tissu hematopoietique de la meme facon. La proliferation de la moelle osseuse isologue et heterologue, dans la chambre anterieure de l'oeil, lui a permis de mettre en evidence une certaine capacite de survie et de proliferation de ce tissu irradie meme a dose supraletale. Par une contre-experimentation, c'est-a-dire par la greffe de moelle non irradiee dans la chambre anterieure de rats irradies a 700 rads, il conclut que le milieu ambiant, intoxique par l'irradiation, agit sur le greffon de telle sorte que ce dernier, apres s'etre vascularise, devient depourvu de son aptitude de proliferation. (auteur)

The nature of the initiating centres for grafting in air-irradiated perfluoro polymers

International Nuclear Information System (INIS)

Bozzi, A.; Chapiro, A.

1987-01-01

Grafting of acrylic acid on polytetrafluoroethylene has been performed using films of the polymer gamma-irradiated in air and then treated with aqueous acrylic acid. It is concluded that the initiating centres are peroxides POOP', where P' is a small perfluorinated fragment, and also trapped peroxy radicals PO 2 radical which undergo deoxygenation. Homopolymerization is suppressed by polymerization inhibitors. (author)

Survival of dental implants in native and grafted bone in irradiated head and neck cancer patients: a retrospective analysis.

Science.gov (United States)

Buddula, Aravind; Assad, Daniel A; Salinas, Thomas J; Garces, Yolanda I

2011-01-01

To study the long-term survival of dental implants placed in native or grafted bone in irradiated bone in subjects who had received radiation for head and neck cancer. A retrospective chart review was conducted for all patients who received dental implants following radiation treatment for head and neck cancer between May 1, 1987 and July 1, 2008. Only patients irradiated with a radiation dose of 50 Gy or greater and those who received dental implants in the irradiated field after head and neck radiation were included in the study. The associations between implant survival and patient/implant characteristics were estimated by fitting univariate marginal Cox proportional hazards models. A total of 48 patients who had prior head and neck radiation had 271 dental implants placed during May 1987-July 2008. There was no statistically significant difference between implant failure in native and grafted bone (P=0.76). Survival of implants in grafted bone was 82.3% and 98.1% in maxilla and mandible, respectively, after 3 years. Survival of implants in native bone in maxilla and mandible was 79.8% and 100%, respectively, after 3 years. For implants placed in the native bone, there was a higher likelihood of failure in the maxilla compared to the mandible and there was also a tendency for implants placed in the posterior region to fail compared to those placed in the anterior region. There was no significant difference in survival when implants were placed in native or grafted bone in irradiated head and neck cancer patients. For implants placed in native bone, survival was significantly influenced by the location of the implant (maxilla or mandible, anterior or posterior).

Synthesis and property characterization of cassava starch grafted poly(acrylamide-co-(maleic acid)) superabsorbent via γ-irradiation

International Nuclear Information System (INIS)

Kiatkamjornwong, Suda; Mongkolsawat, Kanlaya; Sonsuk, Manit

2004-01-01

Graft copolymerizations of acrylamide and maleic acid onto cassava starch by a simultaneous irradiation technique using γ-rays as a initiator were carried out. Various important parameters of total dose, dose rate, monomer-to-cassava starch ratio and maleic acid content were studied. Addition of 2% ww -1 diprotic acid of maleic acid into the reaction mixture yields a saponified starch graft copolymer with a water absorption in distilled water as high as 2256g g -1 of its dried weight. The water absorption of these saponified graft copolymers insaline and buffer solutions was also measured. The water absorption depends largely on the cationic type and concentration of these solutions in terms of ionic strength. This research explains a charge transfer mechanism for graft copolymerization of maleic acid and acrylamide onto cassava starch, and describes the influential parameters that affect grafting efficiency and water absorption. (author)

Hydrophilic microfiltration membranes prepared from acryl amide grafted PVDF powder by γ-rays pre-irradiation

International Nuclear Information System (INIS)

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

2011-01-01

Acryl amide (AAm) was grafted onto poly (vinylidene fluoride) (PVDF) powder by a γ-rays pre-irradiation induced graft polymerization technique. The DG values of the PVDF-g-PAM powder were determined by fluorine elemental analysis. Effects of grafting time on DG of PVDF-g-PAM powder at the same monomer concentration were studied. And modified powder was dissolved in NMP and added PVP as pre-forming agent. The microfiltration (MF) membranes were cast using a phase inversion method. The contact angle, degree of swelling, water flux and antifouling properties of those modified MF membranes were investigated. The results indicated that the hydrophilicity of modified MF membranes was improved obviously and the antifouling property of modified MF membranes (DG of 13%) was better than that of the pristine membrane. (authors)

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)

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)

Localized surface grafting reactions on carbon nanofibers induced by gamma and e-beam irradiation

Energy Technology Data Exchange (ETDEWEB)

Evora, M.C., E-mail: cecilia@ieav.cta.br [Institute for Advanced Studies-IEAV/DCTA, Av. Cel Jose Alberto Albano do Amarante, 1-Putim, 12228-001 São Jose dos Campos, SP (Brazil); Araujo, J.R., E-mail: jraraujo@inmetro.gov.br [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias, RJ (Brazil); Ferreira, E.H.M. [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias, RJ (Brazil); Strohmeier, B.R. [Thermo Fisher Scientific, 5225 Verona Road, Madison, WI 53711 (United States); Silva, L.G.A., E-mail: lgasilva@ipen.br [Institute for Nuclear and Energy Research- IPEN, Av. Prof lineu Prestes, 2242- Cidade Universitaria, 05508-000 SP (Brazil); Achete, C.A. [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias, RJ (Brazil)

2015-04-30

Graphical abstract: - Highlights: • Methodology for the functionalization of carbon nanofibers was investigated. • Two radiation sources were used to promote grafting reactions: gamma and electron beam. • We report the optimum inhibitor concentration to achieve the functionalization. • Surface of carbon nanofibers showed an increase of oxygen content after irradiation. • The radiation-induced graphitization did not damage the overall sp{sup 2} structure. - Abstract: Electron beam and gamma-ray irradiation have potential application to modify the carbon fiber nanostructures in order to produce useful defects in the graphitic structure and create reactive sites. In this study, the methodology to functionalize carbon nanofiber (CNF), via a radiation process and using acrylic acid as a source of oxygen functional groups, was investigated. The samples were submitted to a direct grafting radiation process with electron beam and gamma-ray source. Several parameters were changed such as: acrylic acid concentration, radiation dose and percentage of inhibitor necessary to achieve functionalization, with higher percentage of oxygen functional groups on CNF surface, and better dispersion. The better results achieved were when mixing CNF in a solution of acrylic acid with 6% of inhibitor (FeSO{sub 4}·7H{sub 2}O) and irradiated at 100 kGy. The samples were characterized by X-ray photoelectron spectroscopy and the surface composition (atomic%) showed a significant increase of oxygen content for the samples after irradiation. Also, the dispersion of the functionalized CNF in water was stable during months which may be a good indication that the functionalization process of CNF via ionizing radiation was successful.

Localized surface grafting reactions on carbon nanofibers induced by gamma and e-beam irradiation

International Nuclear Information System (INIS)

Evora, M.C.; Araujo, J.R.; Ferreira, E.H.M.; Strohmeier, B.R.; Silva, L.G.A.; Achete, C.A.

2015-01-01

Graphical abstract: - Highlights: • Methodology for the functionalization of carbon nanofibers was investigated. • Two radiation sources were used to promote grafting reactions: gamma and electron beam. • We report the optimum inhibitor concentration to achieve the functionalization. • Surface of carbon nanofibers showed an increase of oxygen content after irradiation. • The radiation-induced graphitization did not damage the overall sp 2 structure. - Abstract: Electron beam and gamma-ray irradiation have potential application to modify the carbon fiber nanostructures in order to produce useful defects in the graphitic structure and create reactive sites. In this study, the methodology to functionalize carbon nanofiber (CNF), via a radiation process and using acrylic acid as a source of oxygen functional groups, was investigated. The samples were submitted to a direct grafting radiation process with electron beam and gamma-ray source. Several parameters were changed such as: acrylic acid concentration, radiation dose and percentage of inhibitor necessary to achieve functionalization, with higher percentage of oxygen functional groups on CNF surface, and better dispersion. The better results achieved were when mixing CNF in a solution of acrylic acid with 6% of inhibitor (FeSO 4 ·7H 2 O) and irradiated at 100 kGy. The samples were characterized by X-ray photoelectron spectroscopy and the surface composition (atomic%) showed a significant increase of oxygen content for the samples after irradiation. Also, the dispersion of the functionalized CNF in water was stable during months which may be a good indication that the functionalization process of CNF via ionizing radiation was successful

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)

Survival of dental implants in native and grafted bone in irradiated head and neck cancer patients: A retrospective analysis

Directory of Open Access Journals (Sweden)

Aravind Buddula

2011-01-01

Full Text Available Aim: To study the long-term survival of dental implants placed in native or grafted bone in irradiated bone in subjects who had received radiation for head and neck cancer. Materials and Methods: A retrospective chart review was conducted for all patients who received dental implants following radiation treatment for head and neck cancer between May 1, 1987 and July 1, 2008. Only patients irradiated with a radiation dose of 50 Gy or greater and those who received dental implants in the irradiated field after head and neck radiation were included in the study. The associations between implant survival and patient/implant characteristics were estimated by fitting univariate marginal Cox proportional hazards models. Results: A total of 48 patients who had prior head and neck radiation had 271 dental implants placed during May 1987-July 2008. There was no statistically significant difference between implant failure in native and grafted bone (P=0.76. Survival of implants in grafted bone was 82.3% and 98.1% in maxilla and mandible, respectively, after 3 years. Survival of implants in native bone in maxilla and mandible was 79.8% and 100%, respectively, after 3 years. For implants placed in the native bone, there was a higher likelihood of failure in the maxilla compared to the mandible and there was also a tendency for implants placed in the posterior region to fail compared to those placed in the anterior region. Conclusion: There was no significant difference in survival when implants were placed in native or grafted bone in irradiated head and neck cancer patients. For implants placed in native bone, survival was significantly influenced by the location of the implant (maxilla or mandible, anterior or posterior.

Expression of bone morphogenic protein 2/4, transforming growth factor-β1, and bone matrix protein expression in healing area between vascular tibia grafts and irradiated bone-experimental model of osteonecrosis

International Nuclear Information System (INIS)

Schultze-Mosgau, Stefan; Lehner, Bernhard; Roedel, Franz; Wehrhan, Falk; Amann, Kerstin; Kopp, Juergen; Thorwarth, Michael; Nkenke, Emeka; Grabenbauer, Gerhard

2005-01-01

Purpose: For the surgical treatment of osteoradionecrosis after multimodal therapy of head-and-neck cancers, free vascular bone grafts are used to reconstruct osseous structures in the previously irradiated graft bed. Reduced, or even absent osseous healing in the transition area between the vascular graft and the irradiated graft bed represents a clinical problem. Inflammatory changes and fibrosis lead to delayed healing, triggered by bone morphogentic protein 2/4 (BMP2/4) and transforming growth factor (TGF)-β 1 . Given the well-known fibrosis-inducing activity of TGF-β 1 , an osteoinductive effect has been reported for BMP2/4. However, the influence of irradiation (RT) on this cytokine expression remains elusive. Therefore, the aim of the present in vivo study was to analyze the expression of BMP2/4, TGF-β 1 , collagen I, and osteocalcin in the transition area between the bone graft and the graft bed after RT. Methods and materials: Twenty Wistar rats (male, weight 300-500 g) were used in this study. A free vascular tibia graft was removed in all rats and maintained pedicled in the groin region. Ten rats underwent RT with 5 x 10 Gy to the right tibia, the remainder served as controls. After 4 weeks, the previously removed tibia grafts were regrafted into the irradiated (Group 1) and nonirradiated (Group 2) graft beds. The interval between RT and grafting was 4 weeks. After a 4-week osseous healing period, the bone grafts were removed, and the transition area between the nonirradiated graft and the irradiated osseous graft bed was examined histomorphometrically (National Institutes of Health imaging program) and immunohistochemically (avidin-biotin-peroxidase complex) for the expression of BMP2/4, TGF-β 1 , collagen I, and osteocalcin. Results: Absent or incomplete osseous healing of the graft was found in 9 of 10 rats after RT with 50 Gy and in 1 of 10 of the rats with nonirradiated osseous grafts. Histomorphometrically, the proportion of osseous healing in

Preparation and characterization of acrylic acid-grafted poly (vinyl alcohol) hydrogel actuators using γ-ray irradiation

International Nuclear Information System (INIS)

An, Sung Jun; Lim, Youn Mook; Gwon, Hui Jeong; Kim, Yun Hye; Youn, Min Ho; Nho, Young Chang; Han, Dong Hyun; Kim, Chong Yeal

2008-01-01

Active polymer gels expand and contract in response to certain environmental stimuli, such as the application of an electric field or a change in the pH level of the surroundings. This ability to achieve large, reversible deformations with no external mechanical loading has generated much interest in the use of these gels as biomimetic actuators and artificial muscles. In this study, poly (vinyl alcohol)(PVA) grafted acrylic acid monomer (PVA-g-AAc) hydrogels were prepared by 60 Co γ-ray irradiation and their properties such as degree of grafting and weight swelling in electrostimulation as an artificial muscle and actuator were investigated

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.

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).

Brazilian situation of blood component irradiation practice for the prevention of transfusion associated Graft-versus-Host disease

International Nuclear Information System (INIS)

Goes, E.G.; Borges, J.C.; Covas, D.T.; Motta, I.

1998-01-01

Transfusion-associated graft-versus-host disease (TA-GVHD) is a usually complication of transfusion of blood component containing T lymphocytes what recently has also involved immunocompetent patient. Gamma irradiation of cellular blood components has been the mainstay against TA-GVHD, nevertheless there is little information in the literature about current transfusion medicine practices regarding gamma irradiation of blood products. This work presents an overview of the Brazilian reality and suggests policies to optimize TA-GVHD prevention. (Author)

Brazilian situation of blood component irradiation practice for the prevention of transfusion associated Graft-versus-Host disease

Energy Technology Data Exchange (ETDEWEB)

Goes, E.G.; Borges, J.C. [EE/COPPE-UFRJ (Brazil); Covas, D.T. [Faculdade deMedicina-USP-RP (Brazil); Motta, I. [Instituto Nacional do Cancer- Rio deJaneiro (Brazil)

1998-12-31

Transfusion-associated graft-versus-host disease (TA-GVHD) is a usually complication of transfusion of blood component containing T lymphocytes what recently has also involved immunocompetent patient. Gamma irradiation of cellular blood components has been the mainstay against TA-GVHD, nevertheless there is little information in the literature about current transfusion medicine practices regarding gamma irradiation of blood products. This work presents an overview of the Brazilian reality and suggests policies to optimize TA-GVHD prevention. (Author)

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.

Skin graft influence in human tissue radiated in nude mice regeneration

International Nuclear Information System (INIS)

Miranda, Jurandir Tomaz de

2016-01-01

Over the last few years it has increased the interest in the human skin grafts radio sterilized for application mainly in extensive and deep burns. Because these grafts quickly grip and present antigenic lower potential, compared with other treatments used. The purpose of this study was to evaluate the histoarchitecture of human skin grafts irradiated with doses 25 kGy, 50 kGy and non-irradiated during the repair tissue process in nude mice submitted by skin grafting in the dorsal region. Three groups of animals received irradiated human skin grafts (25 kGy and 50 kGy) and non-irradiated and were euthanized on the 3 rd , 7 th and 21 th day after the surgery. Indeed, routine histologic procedures, tissue samples were stained with hematoxylin and eosin (HE) for quantification of keratinocytes, fibroblasts, immune cells and blood vessels and immunofluorescence (IF) was performed to determine the expression human collagen type I and collagen type I and III mouse. Therefore, quantification of both the cells and the collagen types was performed by image analysis using Image-Pro Plus 6.0 software. Histologic results demonstrated at a dose of 25 kGy that human skin irradiation when grafted influences the increase in the number of cells in wound site over time and it provides better dispersion of these cells. In addition, on the 21 st day, three groups of animals with human skin graft were embedded part of the graft in the healing process. On the other hand, the group not irradiated showed greater incorporation of the graft (43 %), but less production of collagen type III mouse (22 %). Since the groups irradiated skin graft showed lower graft incorporation (6 and 15%), but with greater production of collagen type III mice (35 % and 28 % to 25 kGy and 50 kGy, respectively). In conclusion, this study presented that the group irradiated to 25 kGy and it has a higher cell proliferation and vessel formation, and better remodeling of the healing area. (author)

Immune reactivity after high-dose irradiation

International Nuclear Information System (INIS)

Gassmann, W.; Wottge, H.U.; von Kolzynski, M.; Mueller-Ruchholtz, W.

1986-01-01

Immune reactivity after total-body irradiation was investigated in rats using skin graft rejection as the indicator system. After sublethal irradiation with 10.5 Gy (approximately 50% lethality/6 weeks) the rejection of major histocompatibility complex allogeneic skin grafts was delayed significantly compared with nonirradiated control animals (28 versus 6.5 days). In contrast, skin grafts were rejected after 7.5 days in sublethally irradiated animals and 7 days in lethally irradiated animals if additional skin donor type alloantigens--namely, irradiated bone marrow cells--were given i.v. either simultaneously or with a delay of not more than 24 hr after the above conditioning regimen. These reactions were alloantigen-specific. They were observed in six different strain combinations with varying donors and recipients. Starting on day 2 after irradiation, i.v. injection of bone marrow gradually lost its effectivity and skin grafts were no longer rejected with uniform rapidity; skin donor marrow given on days 4 or 8 did not accelerate skin graft rejection at all. These data show that for approximately 1-2 days after high-dose total-body irradiation rats are still capable of starting a vigorous immune reaction against i.v.-injected alloantigens. The phenomenon of impaired rejection of skin grafted immediately after high-dose irradiation appears to result from the poor accessibility of skin graft alloantigens during the early postirradiation phase when vascularization of the grafted skin is insufficient

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)

Intraoperative extracorporeal autogenous irradiated tendon grafts for functional limb salvage surgery of soft tissue sarcomas of the wrist and hand.

Science.gov (United States)

Omori, Shinsuke; Hamada, Kenichiro; Outani, Hidetatsu; Oshima, Kazuya; Joyama, Susumu; Tomita, Yasuhiko; Naka, Norifumi; Araki, Nobuhito; Yoshikawa, Hideki

2015-05-12

In patients with soft tissue sarcoma of the wrist and hand, limb salvage operation is extremely challenging for surgeons in attempting a complete tumor resection with negative surgical margins. In this study, we report four patients with soft tissue sarcoma of the wrist and hand treated by limb salvage operation with intraoperative extracorporeal autogenous irradiated tendon grafts. The patients were all male, and the mean age at the time of surgery was 45 years. Histological diagnoses included clear cell sarcoma in two patients, synovial sarcoma in one, and angiosarcoma in one. All four patients had high grade tumors, wherein three had American Joint Committee on Cancer (AJCC) stage III disease and one with AJCC stage IV disease. The tumors were resected en bloc with involved tendons. The tendons were isolated from the resected tissues, irradiated ex vivo, and re-implanted into the host tendons. In one patient, the bone was resected additionally because of tumor invasion to the bone. Hand function was evaluated using Musculoskeletal Tumor Society (MSTS) rating system. Of the four patients, three died of distant metastatic disease. The remaining patient lives and remains disease-free. The mean follow-up period was 33 months. One patient had local recurrence outside the irradiated graft at 20 months after surgery. The functional rating was 22. Lower scores were seen in patients with reconstruction of flexor tendons than extensor tendons. Limb salvage operation with intraoperative extracorporeal autogenous irradiated tendon grafts is an acceptable method in selected patients with soft tissue sarcoma of the wrist and hand.

Enhancement of water retention by cross-linked carboxymethylcellulose through polystyrene grafting or γ irradiation

International Nuclear Information System (INIS)

Bhattacharjee, S.S.; Perlin, A.S.

1975-01-01

The absorbency and retention characteristics of crosslinked carboxymethylcellulose (CLCMC) with respect to water and saline can be substantially improved by two different treatments. One treatment involves γ-radioinduced grafting of polystyrene onto fibers of CLCMC. At a critical level of grafting (approximately 25 percent) the retentive capacity of the fibers is almost doubled. Particularly noteworthy is the sharp increase that follows an initial drop in retentivity. It is concluded the polystyrene becomes associated preferentially with residual ordered regions of the CLCMC macromolecule, through the localization of free radicals in these regions. A second means for enhancing the water and saline retention value of CLCMC, consists of subjecting the material to gamma irradiation from a 60 Co source. Dosages used have ranged from 1.0 to 4.8 megarads (MR), depending on the degree of substitution of the initial carboxymethylcellulose. (JGB)

Total lymph-node irradiation and pretreatment with cyclophosphamide in preparation for bone-marrow grafting for aplastic anaemia

International Nuclear Information System (INIS)

Jansen, J.; Zwaan, F.E.; Noordijk, E.M.

1981-01-01

Bone-marrow transplantation (BMT), using bone marrow from an HLA-identical brother or sister constitutes the treatment of choice in most young patients with severe aplastic amaemia. The cases are described of 6 patients who were prepared for grafting by administration of cyclophosphamide (4 days, 50 mg/kg body weight day) and total lymph-node irradiation (750 rad in a single dose). One patient died on the 26th day after BMT from a disseminated Aspergillus infection, and another on the 28th day from the consequences of graft-versus-host disease (GVH disease). One patient recovered after an episode of GVH disease. Two patients developed no complications after the grafting. One female patient, who for the lack of an HLA-identical brother or sister had been grafted with bone marrow of her father whose HLA-phenotype was identical, was normalized haematologically but developed chronic GVH disease of the skin. This method of preparation for BMT for aplastic anaemia reduces the risk of rejection of the bone marrow to a minimum, and may well reduce the frequency and severity of GVH disease. (Auth.)

Effect of BCNU combined with total body irradiation or cyclophosphamide on survival of dogs after autologous marrow grafts

International Nuclear Information System (INIS)

Paterson, A.H.G.; English, D.

1979-01-01

Dogs were treated with either: (1) 750 rad total body irradiation; (2) BCNU 2 or 4 mg/kg IV 48 hours prior to 750 rad total body irradiation; or (3) BCNU 4 mg/kg IV plus cyclophosphamide 30 mg/kg IV. Results showed that of 11 dogs who received 750 rad total body irradiation and did not receive cryopreserved autologous bone marrow cells, none survived, compared to an 88% survival (31 of 35 dogs) after 750 rad total body irradiation if the dogs received stored autologous bone marrow cells. However, when the dogs were treated with BCNU 2 or 4 mg/kg prior to 750 rad total body irradiation the survival rate, despite infusion of autologous bone marrow cells, dropped to 25% (3 of 12 dogs) for BCNU 2 mg/kg, and 17% (2 of 12 dogs) for BCNU 4 mg/kg. This effect did not seem to be due to direct serum inhibition of hemopoietic cell proliferation since serum obtained at various intervals after BCNU administrations failed to inhibit CFU growth in vitro. The dogs died from hemorrhage and infection; at autopsy there was hemorrhagic pneumonitis and intestinal ulcerations with petechial hemorrhages, suggesting that the combination of BCNU and total body irradiation may have synergistic toxicity on the canine gastro-intestinal tract. When BCNU was combined with cyclophosphamide, reversal of marrow toxicity occurred in 54% (6 of 11 dogs) with stored autologous bone marrow cells compared to no survival (0 of 8 dogs) with stored autologous bone marrow cells. Thus while autologous bone marrow grafts are useful for reversal of marrow toxicity due to many therapeutic protocols, such grafts alone may not provide protection against toxicity due to the combination of high dosage BCNU and total body irradiation

Amino acids grafting of Ar+ ions modified PE

International Nuclear Information System (INIS)

Svorcik, V.; Hnatowicz, V.; Stopka, P.; Bacakova, L.; Heitz, J.; Oechsner, R.; Ryssel, H.

2001-01-01

Polyethylene (PE) was irradiated with 63 keV Ar + ions to the fluences from 1x10 12 to 3x10 15 cm -2 and then grafted at room temperature from water solution with amino acids (alanine, leucine). Using various spectroscopic techniques (UV-VIS, FTIR, RBS and EPR) it was shown that the amino acids penetrate into PE where they are eventually captured either on double bonds or on free radicals created by the ion irradiation. Grafting with amino acids in the whole specimen layer modified by irradiation is observed. The ion-beam-modified and amino-acid grafted PE is supposed to exhibit increased biocompatibility. (author)

Radiation-induced grafting of vinylbenzyl chloride onto a poly(ether ether ketone) film

International Nuclear Information System (INIS)

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

2012-01-01

In this study, the effects of various irradiation conditions including solvent, monomer concentration, total dose, and dose rate on the radiation grafting of a VBC monomer onto a PEEK aromatic hydrocarbon film for the preparation of a PVBC-grafted PEEK (PEEK-g-PVBC) film were investigated. The results show that the desired PVBC-grafted PEEK film can be prepared using a simultaneous irradiation grafting method, and that the degree of grafting (DOG) of the film is largely influenced by the irradiation conditions. Among the applied solvents, halogenated solvents, dichloromethane and chloroform, were found to be suitable for grafting. The successful preparation of the grafted film was confirmed using analytical instruments such as FT-IR, TGA, and SEM-EDX.

RADIOCHEMICAL YIELDS OF GRAFT POLYMERIZATION REACTIONS OF CELLULOSE

Energy Technology Data Exchange (ETDEWEB)

Arthur, Jr, J C; Blouin, F A

1963-12-15

The preparation of radioinduced graft polymers of cotton cellulose, while retaining the fibrous nature and high molecular weight of the cellulose, depended primarily on the radiochemical yields of cellulose reactions and of graft polymerization reactions. Yields of the initial major molecular changes in cellulosic polymer indicated that, in the case of scission of the molecule and carboxyl group formation, chain reactions were not initiated by radiation; however, in the case of carbonyl group formation chain reactions were initiated but quickly terminated. Generally, experimental procedures, used in graft polymerization reactions, were: simultaneous irradiation reactions, that is, application of monomers or solutions of monomers to cellulose or chemically modified celluloses, then irradiation; and post-irradiation reactions, that is, irradiation of cellulose or chemically modified celluloses, then after removal from the field of radiation, contacting the irradiated cellulose with monomer. Some of the most important factors influencing the radiochemical yields of graft polymerization reactions, of styrene and acrylonitrile onto cellulose were: concentration of monomer in treating solution; solvent; ratio of monomer solution to cellulose; prior chemical modification of cellulose; and absence of oxygen, particularly in post-irradiation reactions. Experimental data are presented, and the direct and indirect effects of Co/sup 60/ gamma radiation on these reactions are discussed. (auth)

Mixed chimerism and permanent specific transplantation tolerance induced by a nonlethal preparative regimen

International Nuclear Information System (INIS)

Sharabi, Y.; Sachs, D.H.

1989-01-01

The use of allogeneic bone marrow transplantation as a means of inducing donor-specific tolerance across MHC barriers could provide an immunologically specific conditioning regimen for organ transplantation. However, a major limitation to this approach is the toxicity of whole body irradiation as currently used to abrogate host resistance and permit marrow engraftment. The present study describes methodology for abrogating host resistance and permitting marrow engraftment without lethal irradiation. Our preparative protocol involves administration of anti-CD4 and anti-CD8 mAbs in vivo, 300-rad WBI, 700-rad thymic irradiation, and unmanipulated fully MHC-disparate bone marrow. B10 mice prepared by this regimen developed stable mixed lymphohematopoetic chimerism without any clinical evidence of graft-vs.-host disease. Engraftment was accompanied by induction of specific tolerance to donor skin grafts (B10.D2), while third-party skin grafts (B10.BR) were promptly rejected. Mice treated with the complete regimen without bone marrow transplantation appeared healthy and enjoyed long-term survival. This study therefore demonstrates that stable mixed chimerism with donor-specific tolerance can be induced across an MHC barrier after a nonlethal preparative regimen, without clinical GVHD and without the risk of aplasia

Avoidance of graft versus host reactions in cured W-anemic mice

International Nuclear Information System (INIS)

Harrison, D.E.

1976-01-01

Graft-versus-host reactions of parental cells in F 1 hybrids were studied with two unrelated inbred strains of mice that differed at the mouse major histocompatibility locus. W-anemic F 1 recipients were compared with lethally irradiated normal F 1 recipients. Both sets of recipients were populated by marrow and spleen cell grafts from parental and F 1 donors. Most W-anemic F 1 recipients were cured by parental and F 1 cell grafts (except B6 spleen). Even after 13 to 18 months, they showed little or no effect from GVH reactions. Lethally irradiated normal F 1 recipients tolerated parental marrow grafts almost as well, but gave dramatically different results with parental spleen grafts. Seventy-nine of 80 irradiated F 1 recipients of parental spleen grafts died within 1 month. Unlike lethally irradiated recipients, W-anemic recipients have substantial numbers of their own cells along with the donor cells in their lymphoid tissues. These F 1 lymphocytes may interact with parental lymphocytes in vivo to restrain reactions against F 1 allogeneic antigens

Autologous Fat Grafting Reduces Pain in Irradiated Breast: A Review of Our Experience

Directory of Open Access Journals (Sweden)

Fabio Caviggioli

2016-01-01

Full Text Available Introduction. Pain syndromes affect women after conservative and radical breast oncological procedures. Radiation therapy influences their development. We report autologous fat grafting therapeutical role in treating chronic pain in irradiated patients. Materials and Methods. From February 2006 to November 2014, we collect a total of 209 patients who meet the definition of “Postmastectomy Pain Syndrome” (PMPS and had undergone mastectomy with axillary dissection (113 patients or quadrantectomy (96 patients. Both procedures were followed by radiotherapy. We performed fat grafting following Coleman’s procedure. Mean amount of adipose tissue injected was 52 cc (±8.9 cc per breast. Seventy-eight in 209 patients were not treated surgically and were considered as control group. Data were gathered through preoperative and postoperative VAS questionnaires; analgesic drug intake was recorded. Results. The follow-up was at 12 months (range 11.7–13.5 months. In 120 treated patients we detected pain decrease (mean ± SD point reduction, 3.19 ± 2.86. Forty-eight in 59 patients stopped their analgesic drug therapy. Controls reported a mean ± SD decrease of pain of 1.14 ± 2.72. Results showed that pain decreased significantly in patients treated (p<0.005, Wilcoxon rank-sum test. Conclusion. Our 8-year experience confirms fat grafting effectiveness in decreasing neuropathic pain.

Preparation, properties and biological application of pH-sensitive poly(ethylene oxide) (PEO) hydrogels grafted with acrylic acid(AAc) using gamma-ray irradiation

International Nuclear Information System (INIS)

Nho, Y.C.; Mook Lim, Youn; Moo Lee, Young

2004-01-01

pH-sensitive hydrogels were studied as a drug carrier for the protection of insulin from the acidic environment of the stomach before releasing it in the small intestine. In this study, hydrogels based on poly(ethylene oxide) (PEO) networks grafted with acrylic acid (AAc) were prepared via a two-step process. PEO hydrogels were prepared by γ-ray irradiation, and then grafting by AAc monomer onto the PEO hydrogels with the subsequent irradiation (radiation dose: 5-20 kGy, dose rate: 2.15 kGy/h). These grafted hydrogels showed a pH-sensitive swelling behavior. The grafted hydrogels were used as a carrier for the drug delivery systems for the controlled release of insulin. The in vitro drug release behaviors of these hydrogels were examined by quantification analysis with a UV/VIS spectrophotometer. Insulin was loaded into freeze-dried hydrogels (7 mmx3 mmx2.5 mm) and administrated orally to healthy and diabetic Wistar rats. The oral administration of insulin-loaded hydrogels to Wistar rats decreased the blood glucose levels obviously for at least 4 h due to the absorption of insulin in the gastrointestinal tract

Delayed erythropoiesis in irradiated rats grafted with syngeneic marrow: effects of cytotoxic drugs and iron-deficiency anemia

International Nuclear Information System (INIS)

Rodday, P.; Bennett, M.; Vitalle, J.J.

1976-01-01

Erythropoiesis in spleens of lethally irradiated Lewis rats grafted with 4-35 x 10 6 syngeneic marrow cells was inhibited or delayed during the test period of 5 days; this was in marked contrast to observations in irradiated mice. The mechanism of this inhibition was the subject of this study. Pretreatment of recipients 9 days prior to irradiation with the cytotoxic drugs cyclophosphamide (CY), busulfan (BUS), or dimethylmyleran (DMM), or the induction of iron deficiency with anemia in recipients reversed this delayed erythropoiesis. However, neither iron-deficiency anemia nor pretreatment with BUS or DMM affected the ability of irradiated recipients to reject 20 to 50 x 10 6 allogeneic marrow cells. The administration of commercial preparations of erythropoietin to hosts stimulated erythropoiesis moderately. However, proliferation of syngeneic marrow cells was not enhanced when infused into lethally irradiated spontaneous hypertensive (SH) inbred-strain rats which have high levels of endogenous erythropoietin. Finally, plasma from irradiated rats treated with phenylhydrazine to produce severe anemia was rich in erythropoietin but failed to stimulate erythropoiesis in the cell transfer system. Two hypotheses are considered

Improvement of pesticide adsorption capacity of cellulose fibre by high-energy irradiation-initiated grafting of glycidyl methacrylate

International Nuclear Information System (INIS)

Takacs, E.; Wojnarovits, L.; Borsa, J.

2011-01-01

Complete text of publication follows. Sustainable development needs renewable raw materials applied wherever possible. Cellulose is the most abundant biopolymer on earth; various modifications of its properties for special uses are important issues of the research. Some contaminations in wastewaters, e.g. pesticides, are hydrophobic materials; their adsorption on hydrophilic cellulose substrates is very limited. Cotton cellulose was grafted by glycidyl methacrylate in simultaneous grafting using gamma irradiation initiation. Water uptake of cellulose significantly decreased while adsorption of phenol and a pesticide molecule (2,4-dichlorophenoxyacetic acid: 2,4-D) increased upon grafting. As the figure shows on untreated sample even negative 2,4-D adsorption occurred, due to the selective adsorption of water from the solution; the adsorption did not approach its saturation value even in a 30 hours time period investigated. Saturation of phenol adsorption was achieved after 5-6 hours; adsorption equilibrium data of phenol fitted the Langmuir isotherm.

Gamma radiation grafting process for preparing separator membranes for electrochemical cells

International Nuclear Information System (INIS)

Agostino, V.F. D'; Lee, J.Y.

1982-01-01

An irradiation grafting process for preparing separator membranes for use in electrochemical cells, comprises contacting a polymeric base film with an aqueous solution of a hydrophilic monomer and a polymerization retardant; and irradiating said contacted film to form a graft membrane having low electrical resistivity and having monomer molecules uniformly grafted thereon. In the examples (meth) acrylic acid is grafted on to polyethylene, polypropylene and polytetrafluoroethylene in the presence of ferrous sulphate or cupric sulphate as polymerization retardants. (author)

Radiation effect on polystyrene deposited and grafted on silica gel

International Nuclear Information System (INIS)

Kusama, Y.; Udagawa, A.; Takehisa, M.

1978-01-01

The effect of radiation on polystyrene was studied in the presence and absence of silica gel by molecular weight measurement with gel permeation chromatography (GPC). Polystyrene crosslinked under vacuum in the absence of silica gel, but it either crosslinked or degraded by radiation, depending on the molecular weight of the polymer in the presence of silica gel. part of the deposited polymer bonded to silica gel by radiation; the G value for graft-chain formation is in the range of 0.01 to 0.1. Irradiation of polystyrene grafted on silica gel resulted in degradation of the graft chain because of the transfer of energy from silica gel. The G value for main chain scission was about 2 when graft polymer was irradiated in the absence of homopolymer. The degradation of graft polymer was suppressed when the polymer was irradiated in the presence of homopolymer, and the amount of unextractable polymer from silica gel increased with increasing irradiation. This adds evidence to the estimation that an increase in grafting percent coupled with a slight decrease in molecular weight at a later stage of radiation-induced polymerization of styrene adsorbed on slica gel is due to a secondary effect of radiation on the polymer

Fulminant transfusion-associated graft-versus-host disease in a premature infant

International Nuclear Information System (INIS)

Berger, R.S.; Dixon, S.L.

1989-01-01

A fatal case of transfusion-associated graft-versus-host disease developed in a premature infant after receiving several blood products, including nonirradiated white blood cells. Transfusion-associated graft-versus-host disease can be prevented. Irradiation of blood products is the least controversial and most effective method. Treatment was unsuccessful in most reported cases of transfusion-associated graft-versus-host disease. Therefore irradiation of blood products before transfusing to patients susceptible to transfusion-associated graft-versus-host disease is strongly recommended

Engraftment of allogeneic bone marrow without graft-versus-host disease in mongrel dogs using total lymphoid irradiation

International Nuclear Information System (INIS)

Gottlieb, M.; Strober, S.; Hoppe, R.T.; Grumet, F.C.; Kaplan, H.S.

1980-01-01

We achieved long-term engraftment of unmatched bone marrow (BM) in dogs without graft-versus-host disease (GVHD) using a regimen of total lymphoid irradiation (TLI) which could be applied clinically. Twelve normal adult mongrel dogs were given TLI in 18 fractions of 100 rad each (total dose, 1800 rad) over 4 weeks to mantle and abdominal fields in continuity. Nine of the 12 were transfused with one or two random donor whole blood transfusions during the irradiation regimen to determine the risk of sensitization after the onset of immunosuppression. A mean (+- SD) of 0.71 +- 0.54 x 10 9 BM cells/kg of recipient body weight from unrelated sex-mismatched donors was infused within 24 h of the 18th irradiation fraction. Engraftment was assessed by demonstration of donor-type sex chromosomes in spontaneous metaphase spreads of recipient marrow aspirates, and by the appearance of donor-type red blood cells antigens (DEA) in the recipients' blood. Three untransfused and nine transfused recipients were shown to be stable mixed BM chimeras during a followup period of 2 to 11 months after transplantation. Blood transfusion during TLI did not result in graft rejection. We observed no clinical signs of acute or chronic GVHD. TLI has minimal toxicity when compared with conditioning regimens currently used in BM transplantation for aplastic anemia. Potential advantages of the TLI regimen include the opportunity to use unmatched marrow donors and protection from GVHD

Total lymphoid irradiation

International Nuclear Information System (INIS)

Anon.

1980-01-01

An outline review notes recent work on total lymphoid irradiation (TLI) as a means of preparing patients for grafts and particularly for bone-marrow transplantation. T.L.I. has proved immunosuppressive in rats, mice, dogs, monkeys and baboons; when given before bone-marrow transplantation, engraftment took place without, or with delayed rejection or graft-versus-host disease. Work with mice has indicated that the thymus needs to be included within the irradiation field, since screening of the thymus reduced skin-graft survival from 50 to 18 days, though irradiation of the thymus alone has proved ineffective. A more lasting tolerance has been observed when T.L.I. is followed by an injection of donor bone marrow. 50% of mice treated in this way accepted allogenic skin grafts for more than 100 days, the animals proving to be stable chimeras with 50% of their peripheral blood lymphocytes being of donor origin. Experiments of a similar nature with dogs and baboons were not so successful. (U.K.)

In Situ Synthesis of Poly(methyl methacrylate/SiO2 Hybrid Nanocomposites via “Grafting Onto” Strategy Based on UV Irradiation in the Presence of Iron Aqueous Solution

Directory of Open Access Journals (Sweden)

Hong Zhang

2012-01-01

Full Text Available Poly(methyl methacrylate/SiO2 (PMMA/SiO2 hybrid composites were prepared via “grafting onto” strategy based on UV irradiation in the presence of iron aqueous solution. Two steps were used to graft polymethyl methacrylate (PMMA onto the surface of nanosilica, anchoring 3-(methacryloxy propyl trimethoxysilane (MPTS onto the surface of nanosilica to modify it with double bonds, and then grafting PMMA onto the surface of nanosilica with FeCl3 as photoinitiator. The products were characterized by FT-IR, TGA, TEM, DLS, and XPS. The results showed that it is easy to graft PMMA onto the surface of nanosilica under UV irradiation, and the hybrid particles are monodisperse and have core-shell structure with nanosilica as the core and PMMA layers as the shell. Furthermore, the products initiated by FeCl3 have higher monomer conversion, percent grafting, and better monodispersion compared with the products initiated by traditional photoinitiator such as 2-hydroxy-4-(2-hydroxyethoxy-2-methyl-propiophenone (Irgacure 2959.

Nickel adsorption by sodium polyacrylate-grafted activated carbon

Energy Technology Data Exchange (ETDEWEB)

Ewecharoen, A. [Division of Biotechnology, School of Bioresources and Technology, King Mongkut' s University of Technology Thonburi, 83 Moo 8 Thakham, Bangkhuntien, Bangkok 10150 (Thailand); Thiravetyan, P., E-mail: paitip@hotmail.com [Division of Biotechnology, School of Bioresources and Technology, King Mongkut' s University of Technology Thonburi, 83 Moo 8 Thakham, Bangkhuntien, Bangkok 10150 (Thailand); Wendel, E.; Bertagnolli, H. [Institut fuer Physikalische Chemie, Universitaet Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart (Germany)

2009-11-15

A novel sodium polyacrylate grafted activated carbon was produced by using gamma radiation to increase the number of functional groups on the surface. After irradiation the capacity for nickel adsorption was studied and found to have increased from 44.1 to 55.7 mg g{sup -1}. X-ray absorption spectroscopy showed that the adsorbed nickel on activated carbon and irradiation-grafted activated carbon was coordinated with 6 oxygen atoms at 2.04-2.06 A. It is proposed that this grafting technique could be applied to other adsorbents to increase the efficiency of metal adsorption.

Synthesis of a gamma irradiation grafted polytetrafluoroethylene (PTFE) based olefinic copolymer

International Nuclear Information System (INIS)

Ferreto, Helio Fernando Rodrigues

2006-01-01

The extrusion of linear low density polyethylene (LLDPE) is limited by a process related defect known as 'melt fracture' or 'sharkskin', which is a surface defect of the extruded polymer. This defect results in a product with a rough surface that lacks luster and in alterations of specific surface properties. The aim of this study was to obtain a recycled polytetrafluoroethylene polymer with an olefin that could improve the extrudability of the LLDPE. The copolymer was obtained by irradiating recycled PTFE in an inert atmosphere followed by the addition of an olefinic monomer to graft the latter in the polymeric matrix (PTFE). After a certain time of contact, the copolymer was heat treated to permit recombination and elimination of the radicals, both in a reactive and/or inert atmosphere. Three olefinic monomers were used, namely; acetylene, ethylene and 1,3-butadiene. The 1,3-butadiene monomer was found to be more effective with respect to grafting. The specimens were studied using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and differential thermogravimetry (DTG). 0.2-2.0 wt% of the copolymer that was obtained was mixed with LLDPE. The rheological properties of the mixture were determined with a torque rheometer. The results indicated that the process used rendered a copolymer which when added to LLDPE, improved the extrusion process and eliminated the defect 'melt fracture'. (author)

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)

TEMPO addition into pre-irradiated fluoropolymers and living-radical graft polymerization of styrene for preparation of polymer electrolyte membranes

Energy Technology Data Exchange (ETDEWEB)

Sawada, Shin-ichi, E-mail: sawada.shinnichi@jaea.go.j [Conducting Polymer Materials Research Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Department of Nuclear Engineering and Management, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Suzuki, Akihiro; Terai, Takayuki [Department of Nuclear Engineering and Management, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Maekawa, Yasunari, E-mail: maekawa.yasunari@jaea.go.j [Conducting Polymer Materials Research Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)

2010-04-15

We prepared proton exchange membranes (PEMs) by 2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO)-mediated living-radical graft polymerization (LRGP) of styrene into fluoropolymer films and subsequent sulfonation. Poly(vinylidene fluoride) (PVDF) and poly(ethylene-co-tetrafluoroethylene) (ETFE) films were first irradiated and then treated with TEMPO solutions in various solvents. TEMPO addition was confirmed by the test of styrene grafting into TEMPO-treated films at 60 deg. C, at which the LRGP never proceeds. This test enabled us to differentiate the LRGP from the conventional graft polymerization. In order to gain a deep insight about TEMPO-addition reaction, the TEMPO-penetration behavior into the base polymer films was examined by a permeation experiment and computer simulation. Xylene and dioxane were appropriate solvents for the complete introduction of TEMPO into PVDF and ETFE films, respectively. Then, the LRGP of styrene was performed based on the fully TEMPO-capped films at 125 deg. C with various solvents. By using an alcoholic solvent, the degree of grafting was enhanced and it reached a maximum of 38%. This grafted film was sulfonated to prepare a PEM showing an ion exchange capacity of 2.2 meq/g and proton conductivity of 1.6x10{sup -1} S/cm.

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

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.

Grafting of polyethylene films with acrylic acid and acrylonitril using gamma radiation

International Nuclear Information System (INIS)

Ajji, Z.; Al-Nesr, E.

2003-12-01

Acrylic acid (AAc) and acrylonitrile (AN) and their binary mixtures were graft copolymerized onto low density polyethylene (LDPE) films using gamma irradiation. The effects of different parameters on the graft yield were studies such as monomer concentration, inhibitor concentration, and irradiation dose. The obtained grafted films were characterized using FTIR spectroscopy, thermal gravimetry, and differential scanning calorimetry. Water uptake and the ion uptake were also evaluated, and the ability of grafted films to uptake heavy ions such as Ni 2+ and Cu 2+ was discussed. (author)

Separate effects of irradiation and of graft-versus-host reaction on rat mucosal mast cells

International Nuclear Information System (INIS)

Cummins, A.G.; Munro, G.H.; Huntley, J.F.; Miller, H.R.P.; Ferguson, A.

1989-01-01

T cell mediated immune responses in the gut can produce enteropathy and malabsorption. The authors investigated the relevance of mucosal mast cells (MMC) to the mechanisms of this enteropathy by using graft-versus-host reaction (GvHR) in the rat as a model of mucosal delayed type hypersensitivity. x-irradiation, with or without GvHR, led to the virtual disappearance of jejunal MMC, undetectable jejunal rat mast cell protease (RMCPII) and very low levels of RMCPII in serum (all p<0.01 when compared with unirradiated controls). These experiments show that there is a modest expansion in jejunal MMC in unirradiated rats with semiallogeneic GvHR, whereas irradiation, alone or associated with GvHR, profoundly depletes MMC for at least two weeks. The enteropathy of GvHR can evolve in the virtual absence of MMC. (author)

H2 formation by electron irradiation of SBA-15 materials and the effect of Cu(II) grafting

International Nuclear Information System (INIS)

Brodie-Linder, N.; Le Caer, S.; Shahdo Alam, M.; Renault, J.P.; Alba-Simionesco, Ch.

2010-01-01

Measurement of H 2 production from electron irradiation (10 MeV) on SBA-15 materials has shown that adsorbed water is attacked preferentially. Silanol groups are only attacked when they are in the majority with respect to adsorbed water, however they are much less efficient at producing H 2 . The comparison between water content before and after electron irradiation and the corresponding H 2 production indicates that water desorption is the main route to adsorbed water loss for SBA-15 materials. On the other hand, surface silanol groups are more susceptible to attack,leading to H 2 production when SBA-15 samples have undergone extensive thermal treatment. Electron irradiation of SBA-15-Cu materials has shown that the presence of Cu(II) on the surface reduces and inhibits the production of H 2 . This inhibiting power affects adsorbed water bonded to grafted copper but not surface silanol groups. (authors)

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)

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)

Skin allografts in lethally irradiated animals repopulated with syngeneic hemopoietic cells

International Nuclear Information System (INIS)

Schwadron, R.B.

1983-01-01

Total body irradiation and repopulation with syngeneic hemopoietic cells can be used to induce tolerance to major histocompatibility complex (MHC) mismatched heart and kidney grafts in rats and mice. However, this protocol does not work for MHC mismatched skin grafts in rats or mice. Furthermore, LEW rats that accept WF cardiac allografts after irradiation and repopulation reject subsequent WF skin grafts. Treatment of skin allograft donors with methotrexate prior to grafting onto irradiated and reconstituted mice resulted in doubling of the mean survival time. Analysis of which antigens provoked skin graft rejection by irradiation and reconstituted animals revealed the importance of I region antigens. Cardiac allograft acceptance by irradiated and reconstituted animals is mediated by suppressor cells found in the spleen. Adoptively tolerant LEW rats accepted WF skin grafts in 50% of grafted animals. Analysis of this phenomenon revealed that the adoptive transfer procedure itself was important in achieving skin allograft acceptance by these animals. In general, it seems that the lack of ability of irradiated and reconstituted animals to accept fully MHC disparate skin grafts results from the inability of these animals to suppress lymph node effector cells against I region antigen seen on highly immunogenic allogeneic Langerhans cells in the skin

Tolerogenic interactions between CD8+ dendritic cells and NKT cells prevent rejection of bone marrow and organ grafts.

Science.gov (United States)

Hongo, David; Tang, Xiaobin; Zhang, Xiangyue; Engleman, Edgar G; Strober, Samuel

2017-03-23

The combination of total lymphoid irradiation and anti-T-cell antibodies safely induces immune tolerance to combined hematopoietic cell and organ allografts in humans. Our mouse model required host natural killer T (NKT) cells to induce tolerance. Because NKT cells normally depend on signals from CD8 + dendritic cells (DCs) for their activation, we used the mouse model to test the hypothesis that, after lymphoid irradiation, host CD8 + DCs play a requisite role in tolerance induction through interactions with NKT cells. Selective deficiency of either CD8 + DCs or NKT cells abrogated chimerism and organ graft acceptance. After radiation, the CD8 + DCs increased expression of surface molecules required for NKT and apoptotic cell interactions and developed suppressive immune functions, including production of indoleamine 2,3-deoxygenase. Injection of naive mice with apoptotic spleen cells generated by irradiation led to DC changes similar to those induced by lymphoid radiation, suggesting that apoptotic body ingestion by CD8 + DCs initiates tolerance induction. Tolerogenic CD8 + DCs induced the development of tolerogenic NKT cells with a marked T helper 2 cell bias that, in turn, regulated the differentiation of the DCs and suppressed rejection of the transplants. Thus, reciprocal interactions between CD8 + DCs and invariant NKT cells are required for tolerance induction in this system that was translated into a successful clinical protocol. © 2017 by The American Society of Hematology.

Electrolytic membrane formation of fluoroalkyl polymer using a UV-radiation-based grafting technique and sulfonation

Energy Technology Data Exchange (ETDEWEB)

Shironita, Sayoko; Mizoguchi, Satoko; Umeda, Minoru, E-mail: mumeda@vos.nagaokaut.ac.jp [Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188, Niigata (Japan)

2011-03-15

A sulfonated fluoroalkyl graft polymer (FGP) membrane was prepared as a polymer electrolyte. First, the FGP membrane was grafted with styrene under UV irradiation. The grafted FGP was then sulfonated to functionalize it for proton conductivity. The grafting degree of the membrane increased with increasing grafting time during UV irradiation. The proton conductivity of the membrane increased with increasing grafting degree. The swelling ratio was independent of the grafting time, however, the water uptake increased with increasing grafting degree. Based on these results, it was found that the UV-initiated styrene grafting occurred along the membrane thickness direction. Moreover, the membrane was embedded within the glass fibers of the composite. This composite electrolytic membrane had 1.15 times the proton conductivity of a Nafion 117 membrane.

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)

Electron beam induced modification of grafted polyamides

International Nuclear Information System (INIS)

Timus, D.M.; Brasoveanu, M.M.; Bradley, D.A.; Popov, A.M.

1998-01-01

It is well known that irradiation, when applied on its own or in combination with other physical and chemical treatments, can manifest in radiation damage to materials. Radiation processing technology focuses upon producing favourable modification of materials through use of relatively high dose and dose rates. Current interest is in modifying the thermal and electrical properties of textured polymers in an effort to improve safety and wear comfort of clothing. No less important is the production of textiles which are safe to use, both in homes and offices. Present investigations provide additional data in support of findings which show that polyamides, a particular class of textured polymer, are amenable to radiation processing. Accelerated electron beam irradiation of sheets of polyamide fibre results in induced grafting of acrylic and methacrylic acids. The degree of grafting is critically dependent upon irradiation dose and the extent of monomers dilution. Of particular importance is the high correlation which is found between degree of grafting and a decrease in the softening rate of the modified polyamide. A systematic modification of electrical conductivity is also observed. (author)

THE LAWFUL CONSEQUENCES OF BIRTH CERTIFICATE ON CHILDREN ABROGATION

Directory of Open Access Journals (Sweden)

Natasya Immanuela Sandjojo

2017-12-01

Full Text Available Research due to the law on the abrogation of birth certificates against children aims to know the effect of law affecting the child, as well as review of the determination and judgment in court that play a role in the birth certificate abrogation. This research describes the importance of birth certificate because of the low public awareness to perform birth registration. The study uses normative juridical research, which faces legal issues with the process of discovering legal rules, principles, and legal doctrines, with deductive methods, starting from the general thing and then generating specific and legitimate answers. Based on the results of the study, that the abrogation of birth certificate brings great lawful consequences for the child, especially the status and position of the child, as well as the right of alimentation,  which in this study included some examples of determination and court decision about the birth certificate abrogation.

The γ-radiation induced grafting of unsaturated segmented polyurethanes with N-vinyl pyrrolidone

International Nuclear Information System (INIS)

Egboh, S.H.; George, M.H.; Barrie, J.A.

1984-01-01

Linear unsaturated segmented polyurethanes have been modified by hydrophilic grafting at 40 deg C with N-vinyl pyrrolidone, in N,N-dimethylformamide as solvent, using 60 Cobalt γ-irradiation. Graft copolymers were isolated from homopolymers by selective solvent extraction using a Soxhlet apparatus. The effects of reaction time, total dose, temperature and monomer concentration, on the graft yields have been examined. Relatively high irradiation doses were avoided during the grafting experiments to prevent possible degradation of the segmented polyurethanes and gelation of the homopolymer, poly(N-vinyl pyrrolidone). The ungrafted and grafted copolymers were characterized, and the graft copolymers were shown to be more thermally stable than the original polyurethanes, by thermogravimetric analysis. An explanation for the observed variation of the graft yields with some of the experimental variables is suggested. (author)

Immobilization of enzymes and antibodies to radiation grafted polymers for therapeutic and diagnostic applications

Energy Technology Data Exchange (ETDEWEB)

Hoffman, A.S.; Gombotz, W.R.; Uenoyama, S.; Dong, L.C.; Schmer, G.

1986-01-01

Pre-irradiation and mutual radiation grafting were employed to produce poly(methacrylic acid) (MAAc) hydrogels on polypropylene/polyethylene (PP/PE) copolymer films, and porous PP fibers of a plasma filter. A diphenyl picryl hydrazyl (DPPH) assay was developed to measure the surface peroxide concentration of the pre-irradiated PP/PE films prior to grafting. Mutually grafted porous PP fibers were used for subsequent immobilization of L-asparaginase while the mutually grafted PP/PE films were used to immobilize a schistosoma monoclonal antibody.

Influence of x-irradiation on pharyngeal induction in the Planarian, Dugesia japonica japonica

International Nuclear Information System (INIS)

Asai, Etsuo

1980-01-01

Pharyngeal formation was examined in cases where normal or X-irradiated head pieces were transplanted into the postpharyngeal region of normal or irradiated worms. Transplantation experiments were carried out in four different combinations of hosts and grafts: (1) normal host and graft (control), (2) normal host and irradiated graft, (3) irradiated host and normal graft, (4) irradiated host and graft. In the first experiment, well developed pharynges were formed in the areas both anterior and posterior to the graft on the 14th day after transplantation. In the second experiment, formation of new pharynges was delayed compared with that in the first group. In the third experiment, only one pharynx developed in the area posterior to each graft in most cases. In the last experiment, no new pharynx appeared at all. From these results, the influence of X-rays on factors participating in pharyngeal induction was discussed. (author)

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)

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

Perfluorinated polymer grafting: influence of preirradiation conditions

International Nuclear Information System (INIS)

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

2009-01-01

The technological interest of perfluorinated polymers is related to its specific properties like low chemical reactivity and high mechanical and temperature resistance. The development of polymeric membranes for PEM fuel cell dispositives requires beyond these characteristics, a long-life time performance and low cost compared to Nafion membranes. By these material have high crystallinity, the radiation grafting indeed occurs but this process generate a low mechanical resistance aggregate. In this way, it is necessary to render the polymer with a low crystallinity or even amorphous. Generally, irradiation under polymer melt temperatures makes the crystallinity breaking and polymer crosslinking. The main objective of this work was promoting the crosslinking process into perfluorinated polymers by pre-irradiation method and to precede styrene grafting by electron beam irradiation in a second step. The experimental methodology consists in pre-irradiate perfluorinated polymers films like PTFE and PFA under high temperature (> 300 deg C) and vacuum conditions by electron beam irradiation at 5 kGy to 30 kGy doses and 2,85 kGy/s to 22,4 kGy/s dose rates. To obtain temperatures above 300 deg C, it was necessary construct a vacuum chamber with a heating system where temperature process could be follow up in real time. Some molecular alterations in polymeric matrix were analyzed by Mid-ATR-FTIR spectroscopy; macroscopic changes are verified by gravimetry. The styrene grafting onto these samples is realized by electron beam irradiation at doses between 30 and 100 kGy. These results are discussed. (author)

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

Syntheses of amine-type adsorbents with emulsion graft polymerization of glycidyl methacrylate

International Nuclear Information System (INIS)

Seko, N.; Bang, L.T.; Tamada, M.

2007-01-01

Glycidyl methacrylate (GMA) which was precursor monomer for the synthesis of metal ion adsorbent was emulsified by surfactant of Tween 20 (Tw-20). The emulsion of 5% GMA in the water was stable for 48 h at Tw-20 concentration of 0.5%. Graft polymerization of GMA on polyethylene fiber was carried out in the emulsion state at various pre-irradiation doses. Degree of grafting (Dg) reached 103%, 301% and 348% for 1 h grafting at 40 deg. C with pre-irradiation of 10, 30 and 40 kGy, respectively. But the Dg was depressed when the pre-irradiation dose was over 50 kGy since cross-linking occurred simultaneously in the trunk polymer. Dg decreased with increment of Tw-20 concentration in emulsion of 5% GMA at pre-irradiation of 40 kGy. The three kinds of amine-type adsorbents were synthesized by reacting diethylenetriamine (DETA), triethylenetetramine (TETA) and ethylenediamine (EDA) with GMA-grafted polyethylene fiber. The synthesized EDA-type adsorbent had the highest selectivity against U ion and the distribution coefficient was 2.0 x 10 6

Graft rejection as a Th1-type process amenable to regulation by donor Th2-type cells through an interleukin-4/STAT6 pathway.

Science.gov (United States)

Mariotti, Jacopo; Foley, Jason; Ryan, Kaitlyn; Buxhoeveden, Nicole; Kapoor, Veena; Amarnath, Shoba; Fowler, Daniel H

2008-12-01

Graft rejection has been defined as the mirror image of graft-versus-host disease, which is biologically characterized primarily as a Th1-type process. As such, we reasoned that graft rejection would represent a Th1 response amenable to Th2 modulation. Indeed, adoptive transfer of host Th1-type cells mediated rejection of fully MHC-disparate murine bone marrow allografts more effectively than host Th2-type cells. Furthermore, STAT1-deficient host T cells did not differentiate into Th1-type cells in vivo and failed to mediate rejection. We next hypothesized that donor Th2 cell allograft augmentation would prevent rejection by modulation of the host Th1/Th2 balance. In the setting of donor Th2 cell therapy, host-anti-donor allospecific T cells acquired Th2 polarity, persisted posttransplantation, and did not mediate rejection. Abrogation of rejection required donor Th2 cell IL-4 secretion and host T-cell STAT6 signaling. In conclusion, T cell-mediated marrow graft rejection primarily resembles a Th1-type process that can be abrogated by donor Th2 cell therapy that promotes engraftment through a novel mechanism whereby cytokine polarization is transferred to host T cells.

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

Demonstration and suppression of a radioresistant host-versus-graft reaction

International Nuclear Information System (INIS)

Thierfelder, S.; Roessler, R. v.; Ruppelt, W.

1975-01-01

The possibilities of suppressing and measuring a radioresistant host-versus-graft reaction are described. According to the authors, the host-versus-graft immune reaction may outlast whole-body irradiation at high doses. (BSC/AK) [de

Synthesis of electron beam grafted poly-propylene (PP) membranes for selective adsorption of uranium from sea water

International Nuclear Information System (INIS)

Bhardwaj, Y.K.; Virendra Kumar; Sabharwal, S.

2001-01-01

Graft co polymerisation of Acrylonitrile (AN) onto porous polypropylene (PP) by post irradiation technique using electron beam (EB) irradiation were studied with regards to various parameters of importance like grafting time, dose rate and horizontal stacking. Grafting of AN causes hardening as well as yellow colouration of the white flexible PP substrate sheets. Grafting reaches saturation limits of ∼130 % after grafting for 2-3 hours and no significant increase in grafting extents is seen after this period. Higher grafting levels are achieved at low dose rates. Keeping the ratio of volume of grafting solution and weight of PP substrate constant, simultaneous grafting of 10-12 PP sheets can be carried out by horizontal stacking without much variation in the grafting limits between the stacked sheets. (author)

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)

Proton exchange membranes prepared by grafting of styrene/divinylbenzene into crosslinked PTFE membranes

International Nuclear Information System (INIS)

Li Jingye; Ichizuri, Shogo; Asano, Saneto; Mutou, Fumihiro; Ikeda, Shigetoshi; Iida, Minoru; Miura, Takaharu; Oshima, Akihiro; Tabata, Yoneho; Washio, Masakazu

2005-01-01

Thin PTFE membranes were prepared by coating the PTFE dispersion onto the aluminum films. Thus the thin crosslinked PTFE (RX-PTFE) membranes were obtained by means of electron beam irradiation above the melting temperature of PTFE under oxygen-free atmosphere. The RX-PTFE membranes were pre-irradiated and grafted by styrene with or without divinylbenzene (DVB) in liquid phase. The existence of DVB accelerated the initial grafting rate. The styrene grafted RX-PTFE membranes are white colored, on the other hand, the styrene/DVB grafted RX-PTFE membranes are colorless. The proton exchange membranes (PEMs) were obtained by sulfonating the grafted membranes using chlorosulfonic acid. The ion exchange capacity (IEC) values of the PEMs ranging from 1.5 to 2.8 meq/g were obtained. The PEMs made from the styrene/DVB grafted membranes showed higher chemical stability than those of the styrene grafted membranes under oxidative circumstance

Gamma ray-irradiation in fresh allo-joint transplantation

International Nuclear Information System (INIS)

Watanabe, Hiroshi

1995-01-01

In the first of a series of experiments in rat designed to assess the efficacy of gamma ray irradiation in fresh allo-joint transplantation, it was found that the optimal gamma ray dosage was 4 Gy. At this dosage level, the irradiation rays suppressed the viability of marrow cells which had the highest antigenicity, with no injury to the bone or articular cartilage. In a second experiment, a fresh homologous knee joint was irradiated at 4 Gy and then transplanted while administering the donor's splenic cell suspension (for specific immunosuppression) and the immunosuppressive agent cyclosporine (5 mg/kg) to the recipient rat. All the rats that received a pre-irradiated knee joint graft survived until sacrificed for evaluation without showing any sign of host rejection. In these rats, bone fusion had occurred between the host bone and the graft by the 8th postoperative week. Degeneration of the articular cartilage was similar between the rats that had received a pre-irradiated graft and those that had not. These findings indicated that 4 Gy gamma ray irradiation to a graft before transplantation provided an effective means of immunosuppression. (author)

Characteristic of Irradiation Result Film of Poly-Propylene-Co-Ethylene/Poly-ε-Caprolactone and Poly-Propylene Grafted Maleic Anhydrate Blend

International Nuclear Information System (INIS)

Nikham

2004-01-01

The effect of gamma rays irradiation to film of melt-blending polypropylene-co-ethylene (CPP) and poly-ε-caprolactone (PCL) with polypropylene grafted maleic anhydride (PP-g-MAH) blend as compatibilizer has been studied. The objective of the research is to prepare the biodegradable polyblend. The composition blend of CPP/PCL with 0, 10, 15, 20 wt % PP-g-MAH i.e. 100/0, 75/25, 50/50, 25/75 and 0/100 were irradiated by using gamma rays 60 Co with activity 420 kCi at doses; 0, 50, 100, 150, 200 kGy, at dose rate 8.2 kGy/hrs and temperature 90 o C. The elongation at break, tensile strength, gel fraction, enzymatic degradation and heat resistance were evaluated. The results showed that the compatibility of PP-g-MAH to reach good enough polyblend is 20 % weight. Elongation at break film of CPP/PCL 50/50 blend which irradiated at dose 200 kGy decreased, whereas the tensile strength increased. Gel fraction and heat resistance of the film irradiated increased. Enzyme of lipase AK can degraded either without irradiated or irradiated film. Thus quality of the polyblend can be called as biodegradable plastic material. (author)

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

Chromosomal instability and the abrogated G2/M arrest in x-irradiated myelodysplastic syndrome cells

International Nuclear Information System (INIS)

Ban, S.; Sudo, H.; Saegusa, K.; Sagara, M.; Imai, T.; Kimura, A.

2003-01-01

A preliminary epidemiological study demonstrated that myelodysplastic syndrome (MDS) has an excess relative risk per sievert of 13 in atomic bomb survivors in Hiroshima. MDS is the only other radiogenic blood disease apart from leukemia. Clinically, MDS involves dysplastic hematopoiesis and an increased risk of leukemic transformation. Because it is uncertain whether MDS pathogenesis affects lymphoid progenitor cells as well as myeloid progenitor cells, we investigated the karyotypes of bone marrow cells and the micronucleus (MN) frequency in peripheral T lymphocytes of twenty- three atomic bomb survivors with MDS and five normal individuals. Aneuploidy was observed in 10 of 23 patients. Chromosome aberrations were observed in 3 of 12 patients with mild symptoms, and six of 11 patients of severe symptoms. The spontaneous- and X-ray-induced-MN frequencies were significantly higher in MDS patients than in normal individuals. Interestingly, radiation sensitivity increased along with the severity of MDS clinical subtypes. Because many of the patients in this study had not been exposed to chemo- or radiation- therapy, their unusual radiosensitivity may be related to their chromosomal or genomic instability. Immortalized lymphoid cell lines were established from B-lymphocytes infected with Epstein-Barr virus in vitro. The abrogation of radiation-induced-G2/M arrest was observed in 10 of 12 MDS-B lymphoid cell lines, but not in the normal B lymphoid cell lines. Our data suggest that the control of chromosomal stability is impaired in pluripotent stem cells of MDS patients, and that the abrogated G2/M arrest may be involved in the pathophysiology of disease progression and the high radiation sensitivity of patients

Replacement of irradiated epidermis by migration of non-irradiated epidermis in the newt limb: the necessity of healthy epidermis for regeneration

Energy Technology Data Exchange (ETDEWEB)

Lheureux, E. (Universite des Sciences et Techniques, Lille (France). Lab. de Morphogenese Animale)

1983-08-01

An X-irradiated newt limb is able to regenerate if non-irradiated skin as well as non-irradiated muscle is transplanted to the stump. In order to know whether limb regeneration required healthy epidermis or not, a triploid skin cuff was set at the most proximal level of an irradiated limb and muscle was transplanted to the level of the midforearm. The forearm was then amputated through the muscle graft. The result was a complete replacement of diploid irradiated epidermis by triploid epidermis, during the six weeks necessary for regeneration. Another investigation consisted of detecting a possible migration of non-irradiated triploid epidermis along an irradiated limb which had not been amputated. Healthy epidermis was found to migrate distally and replace irradiated epidermis in three weeks. Transplantation of a non-irradiated skin cuff or muscle to an irradiated limb stump was carried out on animals entirely irradiated to prevent any extra healthy epidermis cells from contaminating the regenerating limb epidermis. A regenerate developed from the skin graft but not from muscle graft. It is concluded that healthy epidermis must be present on the limb stump to permit the blastema to develop.

Replacement of irradiated epidermis by migration of non-irradiated epidermis in the newt limb: the necessity of healthy epidermis for regeneration

International Nuclear Information System (INIS)

Lheureux, E.

1983-01-01

An X-irradiated newt limb is able to regenerate if non-irradiated skin as well as non-irradiated muscle is transplanted to the stump. In order to know whether limb regeneration required healthy epidermis or not, a triploid skin cuff was set at the most proximal level of an irradiated limb and muscle was transplanted to the level of the midforearm. The forearm was then amputated through the muscle graft. The result was a complete replacement of diploid irradiated epidermis by triploid epidermis, during the six weeks necessary for regeneration. Another investigation consisted of detecting a possible migration of non-irradiated triploid epidermis along an irradiated limb which had not been amputated. Healthy epidermis was found to migrate distally and replace irradiated epidermis in three weeks. Transplantation of a non-irradiated skin cuff or muscle to an irradiated limb stump was carried out on animals entirely irradiated to prevent any extra healthy epidermis cells from contaminating the regenerating limb epidermis. A regenerate developed from the skin graft but not from muscle graft. It is concluded that healthy epidermis must be present on the limb stump to permit the blastema to develop. (author)

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

Additive effects in radiation grafting and curing

International Nuclear Information System (INIS)

Viengkhou, V.; Ng, L.

1996-01-01

Full text: Detailed studies on the accelerative effect of novel additives in radiation grafting and curing using acrylated monomer/oligomer systems have been performed in the presence of ionising radiation and UV as sources. Methyl methacrylate (MMA) is used as typical monomer for these grafting studies in the presence of the additives with model backbone polymers, cellulose and propropylene. Additives which have been found to accelerate these grafting processes are: mineral acid, occlusion compounds like urea, thermal initiators and photoinitiators as well as multifunctional monomers such as multifunctional acrylates. The results from irradiation with gamma rays have also been compared with irradiation from a 90W UV lamp. The role of the above additives in accelerating the analogous process of radiation curing has been investigated. Acrylated urethanes, epoxies and polyesters are used as oligomers together with acrylated monomers in this work with uv lamps of 300 watts/inch as radiation source. In the UV curing process bonding between film and substrate is usually due to physical forces. In the present work the presence of additives are shown to influence the occurrence of concurrent grafting during cure thus affecting the nature of the bonding of the cured film. The conditions under which concurrent grafting with UV can occur will be examined. A mechanism for accelerative effect of these additives in both grafting and curing processes has been proposed involving radiation effects and partitioning phenomena

Study on grafting of monomer onto natural rubber latex by radiation technique

International Nuclear Information System (INIS)

Nguyen Tan Man; Le Hai; Tran Thi Tam; Le Huu Tu, Pham Thi Sam; Dao Minh Phuong; Ha Thuc Huy

2004-01-01

Radiation vulcanization of natural rubber latex has been extensively developed through programmers assisted by the IAEA and UNDP under RCA in Asia and Pacific Region. R-D has been done in most of the Member States with technical assistance from Japan's Takasaki Radiation Chemistry Establishment. Radiation vulcanized natural rubber latex (RVNRL) has many advantages over the conventional sulfur vulcanized latex, such as absence of nitrosamine and low cytotoxicity. Radiation crosslinking is a room temperature process, itself an important cost advantage, it is easily controlled and desired extend of crosslinking is easily achieved by controlling the dose (irradiation time). Disadvantages of RVNRL to be improved are poor physical properties of film such as low tensile strength and tear strength. The research groups of Japan, Thailand and Indonesia concentrated on the improvement of physical properties of RVNRL using radiation grafted PMMA as additive [2]. F. Sundardi and W. Sofiarti have reported that tensile strength and hardness increased by radiation grafting of styrene onto NR [5]. Ono et al have reported the grafting of MMA onto NR by gamma irradiation at a dose of 5 kGy for producing thermoplastic elastomers [4]. The objective of this project is to report the results of studies of radiation graft-copolymerization of methyl methacrylate (MMA) or styrene (St) onto natural rubber latex in order to improve their physico-mechanical properties and evaluation of grafted material using Small-Angle Neutron Scattering through FNCA Project. The grafting degree of MMA and St onto NR increased with the increase of irradiation dose and monomer concentration. The alteration of grafted products structure was determined by IR method. Tensile strength, Shore A hardness, 100% modulus of grafted products increased with the increase of monomer concentration and irradiation dose while elongation at break decreased. The grafted products were characterized by Transmission Electron

Functionalization of poly (4-vinylpyrrolidone) through γ - radiation induced grafting

International Nuclear Information System (INIS)

Pande, C.S.; Ambasta, A.K.; Kumari, Mamta; Sharma, Ajay

2002-01-01

Cross-linked poly(N-vinylpyrrolidone) and N-vinylimidazole were mutually irradiated in water under nitrogen with γ-radiations. A detailed study of grafting was made under various reaction parameters. The results have been compared with the grafting done in air. (author)

Grafting of styrene onto poly(vinylidene fluoride) films by gamma irradiation; Enxertia de estireno em filmes de poli(fluoreto de vinilideno) induzida por irradiacao gama

Energy Technology Data Exchange (ETDEWEB)

Ferreira, H.P.; Souza, C.P. de; Parra, D.F.; Lugao, A.B., E-mail: hp.ferreira@yahoo.com.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Quimica e Meio Ambiente

2010-07-01

Radiation induced grafting of styrene onto poly(vinylidene fluoride) (PVDF) was studied owing to the crescent interest in use of grafted films to produce membranes with ion exchange capability. A Cobalt-60 source was used, with doses of 5 and 10 kGy, at dose rate of 5 kGy.h{sup -1}, at room temperature, inert atmosphere and according to the simultaneous method. Solutions of styrene/toluene (1:1, v/v) and styrene/N,N-dimethylformamide (DMF) (1:1, v/v) were used. The films were characterized by FT-IR spectroscopy (Infrared Spectroscopy), Differential Scanning Calorimetry (DSC), Thermogravimetric Measurement (TG) and the degree of grafting (DOG) were calculated gravimetrically. Results shown that in studied conditions, DMF allow greatest DOG than toluene and that increasing the irradiation dose correspond an increase in DOG. Infrared and thermal analyses confirmed the presence in the grafted polymers. (author)

Effects of marrow grafting on preleukemia cells and thymic nurse cells in C57BL/Ka mice after a leukemogenic split-dose irradiation

International Nuclear Information System (INIS)

Defresne, M.P.; Greimers, R.; Lenaerts, P.; Boniver, J.

1986-01-01

A split-dose regimen of whole-body irradiation (4 X 175 rad at weekly intervals) induced thymic lymphomas in C57BL/Ka mice after a latent period of 3-9 months. Meanwhile, preleukemia cells arose in the thymus and bone marrow and persisted until the onset of lymphomas. Simultaneously, thymic lymphopoiesis was impaired; thymocyte numbers were subnormal and thymic nurse cells disappeared in a progressive but irreversible fashion. The depletion of these lymphoepithelial complexes, which are normally involved in the early steps of thymic lymphopoiesis, was related to altered prothymocyte activity in bone marrow and to damaged thymic microenvironment, perhaps as a consequence of the presence of preleukemia cells. The grafting of normal bone marrow cells after irradiation prevented the development of lymphomas. However, marrow reconstitution did not inhibit the induction of preleukemia cells. They disappeared from the thymus during the second part of the latent period. At the same time, thymic lymphopoiesis was restored; thymocytes and nurse cell numbers returned to normal as a consequence of the proliferation of grafted marrow-derived cells within the thymus. The results thus demonstrated an intimate relationship between preleukemia cells and an alteration of thymic lymphopoiesis, which particularly involved the nurse cell microenvironment. Some preleukemia cells in marrow-reconstituted, irradiated mice derived from the unirradiated marrow inoculate. Thus these cells acquired neoplastic potential through a factor present in the irradiated tissues. The nature of this indirect mechanism was briefly discussed

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

Graft polymerization of vinyl acetate onto starch. Saponification to starch-g-poly(vinyl alcohol)

International Nuclear Information System (INIS)

Fanta, G.F.; Burr, R.C.; Doane, W.M.; Russell, C.R.

1979-01-01

Graft polymerizations of vinyl acetate onto granular cornstarch were initiated by cobalt-60 irradiation of starch-monomer-water mixtures, and ungrafted poly(vinyl acetate) was separated from the graft copolymer by benzene extraction. Conversions of monomer to polymer were quantitative at a radiation dose of 1.0 Mrad. Over half of the polymer was present as ungrafted poly(vinyl acetate) (grafting efficiency less than 50%), and the graft copolymer contained only 34% grafted synthetic polymer (34% add-on). Lower irradiation doses produced lower conversions of monomer to polymer and gave graft copolymers with lower % add-on. Addition of minor amounts of acrylamide, methyl acrylate, and methacrylic acid as comonomers produced only small increases in % add-on and grafting efficency. Grafting efficiency was increased to 70% when a monomer mixture containing about 10% methyl methacrylate was used. Grafting efficiency could be increased to over 90% if the graft polymerization of vinyl acetate--methyl methacrylate was carried out near 0 0 C; although conversion of monomers to polymer was low and grafted polymer contained 40 to 50% poly(methyl methacrylate). Selected graft copolymers were treated with methanolic sodium hydroxide to convert starch-g-poly(vinyl acetate) to starch-g-poly(vinyl alcohol). The molecular weight of the poly(vinyl alcohol) moiety was about 30,000. The solubility of starch-g-poly(vinyl alcohol) in hot water was less than 50; however, solubility could be increased by substituting either acid-modified or hypochlorite-oxidized for unmodified starch in the graft polymerization reaction. Vinyl acetate was also graft polymerized onto acid-modified starch which had been dispersed and partially solubilized by heating in water. A total irradiation dose of either 1.0 or 0.5 Mrad gave starch-g-poly

Study and Optimization on graft polymerization under normal pressure and air atmospheric conditions, and its application to metal adsorbent

International Nuclear Information System (INIS)

Ueki, Yuji; Chandra Dafader, Nirmal; Hoshina, Hiroyuki; Seko, Noriaki; Tamada, Masao

2012-01-01

Radiation-induced graft polymerization of glycidyl methacrylate (GMA) onto non-woven polyethylene (NWPE) fabric was achieved under normal pressure and air atmospheric conditions, without using unique apparatus such as glass ampoules or vacuum lines. To attain graft polymerization under normal pressure and air atmospheric conditions, the effects of the pre-irradiation dose, pre-irradiation atmosphere, pre-irradiation temperature, de-aeration of GMA-emulsion, grafting atmosphere in a reactor, and dissolved oxygen (DO) concentration in GMA-emulsion on the degree of grafting (Dg) were investigated in detail. It was found that the DO concentration had the strongest influence, the pre-irradiation dose, de-aeration of emulsion and grafting atmosphere had a relatively strong impact, and the pre-irradiation atmosphere and pre-irradiation temperature had the least effect on Dg. The optimum DO concentration before grafting was 2.0 mg/L or less. When a polyethylene bottle was used as a reactor instead of a glass ampoule, graft polymerization under normal pressure and air atmospheric conditions could be achieved under the following conditions; the pre-irradiation dose was more than 50 kGy, the volume ratio of GMA-emulsion to air was 50:1 or less, and the DO concentration in GMA-emulsion during grafting was below 2.0 mg/L. Under these grafting conditions, Dg was controlled within a range of up to 362%. The prepared GMA–grafted NWPE (GMA–g-NWPE) fabric was modified with a phosphoric acid to obtain an adsorbent for heavy metal ions. In the column-mode adsorption tests of Pb(II), the adsorption performance of the produced phosphorylated GMA–g-NWPE fabric (fibrous metal adsorbent) was not essentially dependent on the flow rate of the feed. The breakthrough points of 200, 500, and 1000 h −1 in space velocity were 483, 477 and 462 bed volumes, and the breakthrough capacities of the three flow rates were 1.16, 1.15 and 1.16 mmol-Pb(II)/g-adsorbent.

Study and Optimization on graft polymerization under normal pressure and air atmospheric conditions, and its application to metal adsorbent

Science.gov (United States)

Ueki, Yuji; Chandra Dafader, Nirmal; Hoshina, Hiroyuki; Seko, Noriaki; Tamada, Masao

2012-07-01

Radiation-induced graft polymerization of glycidyl methacrylate (GMA) onto non-woven polyethylene (NWPE) fabric was achieved under normal pressure and air atmospheric conditions, without using unique apparatus such as glass ampoules or vacuum lines. To attain graft polymerization under normal pressure and air atmospheric conditions, the effects of the pre-irradiation dose, pre-irradiation atmosphere, pre-irradiation temperature, de-aeration of GMA-emulsion, grafting atmosphere in a reactor, and dissolved oxygen (DO) concentration in GMA-emulsion on the degree of grafting (Dg) were investigated in detail. It was found that the DO concentration had the strongest influence, the pre-irradiation dose, de-aeration of emulsion and grafting atmosphere had a relatively strong impact, and the pre-irradiation atmosphere and pre-irradiation temperature had the least effect on Dg. The optimum DO concentration before grafting was 2.0 mg/L or less. When a polyethylene bottle was used as a reactor instead of a glass ampoule, graft polymerization under normal pressure and air atmospheric conditions could be achieved under the following conditions; the pre-irradiation dose was more than 50 kGy, the volume ratio of GMA-emulsion to air was 50:1 or less, and the DO concentration in GMA-emulsion during grafting was below 2.0 mg/L. Under these grafting conditions, Dg was controlled within a range of up to 362%. The prepared GMA-grafted NWPE (GMA-g-NWPE) fabric was modified with a phosphoric acid to obtain an adsorbent for heavy metal ions. In the column-mode adsorption tests of Pb(II), the adsorption performance of the produced phosphorylated GMA-g-NWPE fabric (fibrous metal adsorbent) was not essentially dependent on the flow rate of the feed. The breakthrough points of 200, 500, and 1000 h-1 in space velocity were 483, 477 and 462 bed volumes, and the breakthrough capacities of the three flow rates were 1.16, 1.15 and 1.16 mmol-Pb(II)/g-adsorbent.

Allogeneic hematopoietic cell transplantation in first remission abrogates poor outcomes associated with high-risk pediatric acute myeloid leukemia.

Science.gov (United States)

Burke, Michael J; Wagner, John E; Cao, Qing; Ustun, Celalettin; Verneris, Michael R

2013-07-01

Despite remission rates of approximately 85% for children diagnosed with acute myeloid leukemia (AML), greater than 40% will die from relapsed disease. Patients with poor-risk molecular/cytogenetics and/or inadequate response to up-front therapy are typically considered high-risk (HR) and historically have poor outcomes with chemotherapy alone. We investigated whether allogeneic hematopoietic cell transplantation (allo-HCT) with best available donor in first remission (CR1) would abrogate the poor outcomes associated with HR AML in children and young adults treated with chemotherapy. We reviewed the outcomes of 50 consecutive children and young adults (ages 0 to 30 years) with AML who received a myeloablative allo-HCT between 2001 and 2010. Thirty-six patients (72%) were HR, defined as having FLT3-ITD mutations, 11q23 MLL rearrangements, chromosome 5 or 7 abnormalities, induction failure, and/or having persistent disease. The majority of patients received cyclophosphamide and total body irradiation conditioning, and graft-versus-host-disease (GVHD) prophylaxis was cyclosporine based. Transplantation outcomes for HR patients were compared to standard-risk patients, with no significant differences observed in overall survival (72% versus 78%, P = .72), leukemia-free survival (69% versus 79%, P = .62), relapse (11% versus 7%, P = .71), or treatment-related mortality (17% versus 14%, P = .89). Children and young adults with HR-AML have comparable outcomes to standard-risk patients following allo-HCT in CR1. Copyright © 2013 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

Radiotherapy in allogenic renal transplantation: an indication for local graft irradiation?

International Nuclear Information System (INIS)

Micke, O.; Bruns, F. U.; Schaefer, U.; Willich, N.; Seegenschmiedt, M.H.; Matzkies, F.K.

2002-01-01

Patients and Methods: Between 1979 and 1990, eight patients with biopsy-proven acute renal allograft rejection and failure of all other immunosuppressive measures (corticosteroids, ATG, ALG or OKT3) were treated with LGI. Retrospective analysis was conducted for this control group. Radiotherapy was performed with Co-60 up to a median total dose of 6.0 Gy (single doses: 1.5-2.0 Gy). Six of eight patients were dialysis dependent prior to irradiation. In addition a literature review was performed including most important textbooks, electronic databases (Medline, Embase, Science Citations Index), and the internet. Results: Two of eight patients experienced a clinical reversal of rejection and an improvement of renal function: serum creatinine decreased significantly. One patient remained free of dialysis with a functioning graft, the other had a recurrent rejection 2 months later and became dialysis dependent. The literature review showed, that adjuvant LGI has no advantage over conventional immunosuppression. However, in case of a drug refractory allograft rejection LGI restores long-term stable organ function in 13-60% of cases. (orig.) [de

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

Preparation of poly (vinyl alcohol) membranes grafted with n-vinyl pyridine/ acrylic acid binary monomers

International Nuclear Information System (INIS)

Ajji, A.; Ali, A.

2014-03-01

Poly(vinyl alcohol) films were grafted with two monomers using gamma radiation, acrylic acid and N-vinyl pyridine. The influence of different parameters on the grafting yield was investigated as: the comonomer concentration and composition, and irradiation dose. The suitable conditions of the process had been determined to prepare PVA membranes have both properties of the two monomers, acrylic acid and vinyl pyridine as comonomer concentration and composition, and irradiation dose. Some properties of the membranes had been investigated as maximum swelling and grafting. Also the ability of the grafted films to adsorb some heavy metals and dyes was elaborated and discussed.(author)

Obtention of graft copolymers by ionizing radiation, characterization and study of hemo-compatible properties

International Nuclear Information System (INIS)

Queiroz, A.A.A. de.

1993-01-01

The present work had as objectives the obtention and characterization of grafting copolymers by radiation induced polymerization and the study of its hemo compatible properties. The relationship between grafting conditions and anti-trombogenicity was examined for the purpose of clearing the necessity of controlling grafting conditions to enhance the copolymers blood compatibility. Two methods were chosen to accomplish the irradiation: mutual and pre-irradiation (peroxidation) of the films in 6O Co source and electron beam accelerator. Primarily grafting parameters were studied in the systems of the monomers N, N-dimethyl acrylamide (DMAA) and acrylic acid (AA) with the polymeric films: poly (tetrafluoroethylene) (PTFE), poly (ethylene-co-tetrafluoroethylene) (PETFE), low density polyethylene (LDPE) and poly (vinyl chloride) (PVC). The simultaneous irradiation was effective in the polymerization of all the substrates above mentioned, although the peroxidation method has given better results for PETFE-DMAA, LDPE-g-DMAA, LDPE-g-AA and PVC-g-AA. In the system AA/LDPE and AA/PVC the homo polymerization was controlled by the addition of the comonomer N, N-dimethyl acrylic acid (DMA). As for the grafting parameters, low dose rate and low irradiation dose, showed to be very effective for the graftability of DMAA and AA on the substrates. (author). 129 refs, 51 figs, 7 tabs

Ebselen abrogates TNFα induced pro‐inflammatory response in glioblastoma

OpenAIRE

Tewari, Richa; Sharma, Vivek; Koul, Nitin; Ghosh, Abhishek; Joseph, Christy; Hossain Sk, Ugir; Sen, Ellora

2008-01-01

We investigated the pro‐inflammatory response mediated by TNFα in glioblastoma and whether treatment with organoselenium Ebselen (2‐phenyl‐1,2‐benzisoselenazol‐3[2H]one) can affect TNFα induced inflammatory response. Exposure to TNFα increased the expression of pro‐inflammatory mediator interleukin IL‐6, IL‐8, monocyte chemoattractant protein‐1 (MCP‐1) and cyclooxygenase (COX‐2). Treatment with Ebselen abrogated TNFα induced increase in pro‐inflammatory mediators. Ebselen not only abrogated T...

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.

Prevention of transfusion-associated graft-versus-host disease by irradiation: technical aspect of a new ferrous sulphate dosimetric system.

Directory of Open Access Journals (Sweden)

Lucas Sacchini Del Lama

Full Text Available Irradiation of whole blood and blood components before transfusion is currently the only accepted method to prevent Transfusion-Associated Graft-Versus-Host-Disease (TA-GVHD. However, choosing the appropriate technique to determine the dosimetric parameters associated with blood irradiation remains an issue. We propose a dosimetric system based on the standard Fricke Xylenol Gel (FXG dosimeter and an appropriate phantom. The modified dosimeter was previously calibrated using a (60Co teletherapy unit and its validation was accomplished with a (137Cs blood irradiator. An ionization chamber, standard FXG, radiochromic film and thermoluminescent dosimeters (TLDs were used as reference dosimeters to determine the dose response and dose rate of the (60Co unit. The dose distributions in a blood irradiator were determined with the modified FXG, the radiochromic film, and measurements by TLD dosimeters. A linear response for absorbed doses up to 54 Gy was obtained with our system. Additionally, the dose rate uncertainties carried out with gel dosimetry were lower than 5% and differences lower than 4% were noted when the absorbed dose responses were compared with ionization chamber, film and TLDs.

Prevention of Transfusion-Associated Graft-versus-Host Disease by Irradiation: Technical Aspect of a New Ferrous Sulphate Dosimetric System

Science.gov (United States)

Del Lama, Lucas Sacchini; de Góes, Evamberto Garcia; Petchevist, Paulo César Dias; Moretto, Edson Lara; Borges, José Carlos; Covas, Dimas Tadeu; de Almeida, Adelaide

2013-01-01

Irradiation of whole blood and blood components before transfusion is currently the only accepted method to prevent Transfusion-Associated Graft-Versus-Host-Disease (TA-GVHD). However, choosing the appropriate technique to determine the dosimetric parameters associated with blood irradiation remains an issue. We propose a dosimetric system based on the standard Fricke Xylenol Gel (FXG) dosimeter and an appropriate phantom. The modified dosimeter was previously calibrated using a 60Co teletherapy unit and its validation was accomplished with a 137Cs blood irradiator. An ionization chamber, standard FXG, radiochromic film and thermoluminescent dosimeters (TLDs) were used as reference dosimeters to determine the dose response and dose rate of the 60Co unit. The dose distributions in a blood irradiator were determined with the modified FXG, the radiochromic film, and measurements by TLD dosimeters. A linear response for absorbed doses up to 54 Gy was obtained with our system. Additionally, the dose rate uncertainties carried out with gel dosimetry were lower than 5% and differences lower than 4% were noted when the absorbed dose responses were compared with ionization chamber, film and TLDs. PMID:23762345

Synthesis of Graft Copolymers by Small Doses of Irradiation; Synthese des copolymeres greffes au moyen de petites doses de rayonnements; Sintez privitykh sopolimerov s pomoshch'yu malykh doz oblucheniya; Sintesis de copolimeros de injerto mediante pequenas dosis de radiacion

Energy Technology Data Exchange (ETDEWEB)

Dobo, J; Somogyi, M; Kiss, L

1960-07-15

In addition to grafting, there is often an undesirable alteration in the properties of the original polymer when polymer monomer mixtures are irradiated. As a result of irradiation, grafting occurs not only on the original polymeric backbone, but also on the already grafted side-chains. The result is an acceleration of grafting. The effect is especially pronounced in the case of preformed polymers, if irradiation is carried out intermittently. The grafting of styrene can be accelerated by the addition of some solvents which suppress the protective effect of the styrene on the polymer. Grafting can be accelerated by other additives. The swelling properties of the irradiated films were investigated. (author) [French] Lorsque des melanges de polymeres et de monomeres sont soumis a des rayonnements, il se produit souvent, en meme temps que la greffe, une alteration facheuse des proprietes du polymere original. L'irradiation provoque une reaction de greffage, non seulement sur le polymere original, mais aussi sur les chaines laterales deja greffees. Il en resulte une acceleration du processus de greffage. L'effet est particulierement marque dans le cas des polymeres preformes, lorsque l'irradiation est effectuee par intermittence. On peut accelerer le processus de greffage du styrolene en ajoutant certains solvants qui suppriment l'action protectrice du styrolene sur le polymere. On peut aussi accelerer le processus a l'aide d'autres additifs. Les auteurs ont etudie les proprietes de gonflement des pellicules irradiees. (author) [Spanish] Simultaneamente con el injerto, bajo la accion de las radiaciones se produce frecuentemente una alteracion de las propiedades del polimero original, efecto que convendria evitar. Por lo tanto, quiza ofrezcan interes los elevados grados de injerto obtenidos en nuestros laboratorios con pequenas dosis de radiacion. La irradiacion no solo provoca una reaccion de injerto en la estructura polimerica original, sino tambien en las cadenas

Total body irradiation: what schedule(s). Les irradiations corporelles totales: quel(s) schema(s)

Energy Technology Data Exchange (ETDEWEB)

Cosset, J M [Institut Curie, 75 - Paris (France)

1993-01-01

In this article, the author explains why a whole-body irradiation is still an essential step before a bone marrow graft. He presents irradiation protocols for acute myeloid leukemia and chronic myeloid leukemia. 14 refs.

Preparation of thermal-responsive chitosan-graft-N-isopropylacrylamide membranes via γ-ray irradiation

International Nuclear Information System (INIS)

Mu Qing; Fang Yue'e

2006-01-01

Poly(N-isopropylacrylamide) (PNIPAAm) has been attracting increasing attention because of its thermosensitivity. Many authors have studied the reaction of chitosan with NIPAAm, with most of the interest being focused on hydrogels. Few research programs, however, were about chitosan membranes grafted with NIPAAm monomer. In this study, a novel thermo-sensitive switching membrane was prepared by radiation-induced simultaneous grafting of NIPAAm onto chitosan membrane. Fourier transform infrared spectroscopy (FT-IR) was used to identify structure of the grafted membranes. Compared to FT-IR spectra of pristine chitosan, the new band at 1535 cm-1 in the grafted membrane was attributed to amide II of PNIPAAm. This indicated that NIPAAm was introduced onto the chitosan membrane. Surface morphology of the grafted membrane was different from the pristine chitosan membrane. The SEM images revealed cypress leaf-like structures adhered tightly to the grafted membrane surface, in comparison to smooth surface of the pristine chitosan membrane. Pure water flux measurements showed that the grafted membrane decreased with the increasing temperature, while water flux of pristine chitosan membrane was constant. It was found that the grafted membrane was sensitive to temperature. The effects of dose, dose rate and the concentration of NIPAAm on the grafting percentage were discussed. The graft yield increased with the monomer concentration and the absorbed dose. (authors)

Immune responses to implanted human collagen graft in rats

International Nuclear Information System (INIS)

Quteish, D.; Dolby, A.E.

1991-01-01

Immunity to collagen implants may be mediated by cellular and humoral immune responses. To examine the possibility of such immunological reactivity and crossreactivity to collagen, 39 Sprague-Dawley rats (female, 10 weeks old, approximately 250 g wt) were implanted subcutaneously at thigh sites with crosslinked, freeze-dried human placental type I collagen grafts (4x4x2 mm) which had been irradiated (520 Gray) or left untreated. Blood was obtained by intracardiac sampling prior to implantation or from normal rats, and at various times afterwards when the animals were sacrificed. The sera from these animals were examined for circulating antibodies to human, bovine and rat tail (type I) collagens by enzyme-linked immunosorbent assay (ELISA). Also, the lymphoblastogenic responses of spleen lymphocytes from the irradiated collagen-implanted animals were assessed in culture by measuring thymidine uptake with autologous and normal rat sera in the presence of human bovine type I collagens. Implantation of the irradiated and non-irradiated collagen graft in rats led to a significant increase in the level of circulating antibodies to human collagen. Also antibody to bovine and rat tail collagens was detectable in the animals implanted with irradiated collagen grafts but at a lower level than the human collagen. There was a raised lymphoblastogenic response to both human and bovine collagens. The antibody level and lymphoblastogenesis to the tested collagens gradually decreased towards the end of the post-implantation period. (author)

Radiation-Induced Grafting with One-Step Process of Waste Polyurethane onto High-Density Polyethylene

Directory of Open Access Journals (Sweden)

Jong-Seok Park

2015-12-01

Full Text Available The recycling of waste polyurethane (PU using radiation-induced grafting was investigated. The grafting of waste PU onto a high-density polyethylene (HDPE matrix was carried out using a radiation technique with maleic anhydride (MAH. HDPE pellets and PU powders were immersed in a MAH-acetone solution. Finally, the prepared mixtures were irradiated with an electron beam accelerator. The grafted composites were characterized by Fourier transformed infrared spectroscopy (FT-IR, surface morphology, and mechanical properties. To make a good composite, the improvement in compatibility between HDPE and PU is an important factor. Radiation-induced grafting increased interfacial adhesion between the PU domain and the HDPE matrix. When the absorbed dose was 75 kGy, the surface morphology of the irradiated PU/HDPE composite was nearly a smooth and single phase, and the elongation at break increased by approximately three times compared with that of non-irradiated PU/HDPE composite.

Bud irradiation to obtain resistence to citrus canker through induction of mutation

International Nuclear Information System (INIS)

Menten, J.O.M.; Pompeu Junior, J.; Dragone, P.; Sobrinho, J.T.; Prada, V.A.; Tulmann Neto, A.; Ando, A.

1989-01-01

The radiosensitivity to gamma rays of the bud of the orange cultivar Pera is determined through irradiation of buds with several doses; the irradiated buds were grafted onto rootstocks of lemon cu. Cravo. The grafting percentage and the development of the V 1 stem from the irradiated buds are analysed; it is concluded that the best dose for induction of mutation is 4,0 OK. New buds are irradiated and grafted with this dose. The V 1 stems are Separeted into 3 Groups, according to the position of the buds on the stem. The V 2 stems are analysed according to the morphological alteraTions due to irradiation. (M.A.C.) [pt

Preparation of poly(acrylic acid)-chitosan hydrogels by gamma irradiation for metal ions sorption

International Nuclear Information System (INIS)

Tran Thu Hong; Le Hai; Nguyen Tan Man; Tran Thi Tam; Pham Thi Le Ha; Pham Thi Sam; Nguyen Duy Hang; Le Huu Tu; Le Van Toan

2013-01-01

Acid acrylic (AAc) was grafted onto crosslinked chitosan to make Chitosan-g-AAc copolymer with concentration of AAc from 0.5 to 15% by gamma irradiation. The optimal dose for grafting of 15% AAc onto chitosan was 5 kGy. Physical and chemical properties of irradiated samples such as SEM images, FTIR spectroscopy, TGA and swelling behavior at different pHs were evaluated. The grafting yield increased with the increase in dose, it reached 52% at 7 kGy irradiation dose. The application were grafted materials to adsorb metals ion from aqueous solutions was also investigated with both ungrafted and grafted chitosan beads under changing pH from 3 to 6. Grafted chitosan presented higher sorption capacity for most of metal ions than unmodified chitosan. (author)

Radiation grafting of bis[2-(methacryloyloxy)ethyl]phosphate unto kenaf fiber for adsorption of rare earth elements

International Nuclear Information System (INIS)

Nor Azillah Fatimah Othman; Selambakkannu, S.; Norliza Ishak; Nor Azwin Shukri; Zulkafli Ghazali

2016-01-01

Full text: In this work kenaf bast fibers were used as trunk polymer for grafting with bis[2-(methacryloyloxy)ethyl]phosphate monomer through radiation induced grafting technique. Kenaf fibers were treated with different concentration of sodium chlorite (NaClO_2) solution at 70 degree Celsius for 6 hours. Kenaf fibers were irradiated with electron beam and reacted with bis[2-(methacryloyloxy)ethyl]phosphate/ water emulsion. Formation of grafting was observed from the increase in degree of grafting and confirmed by FTIR and SEM results. Effects of irradiation dose, reaction time, reaction temperature and monomer concentration on the degree of grafting were studied. Performance of the grafted kenaf fibers were then tested for adsorption of rare earth elements, namely Dysprosium, Neodymium and Holmium. (author)

Skin graft influence in human tissue radiated in nude mice regeneration; Influencia do enxerto de pele humana irradiada na regeneracao tecidual de camundongos nude

Energy Technology Data Exchange (ETDEWEB)

Miranda, Jurandir Tomaz de

2016-07-01

Over the last few years it has increased the interest in the human skin grafts radio sterilized for application mainly in extensive and deep burns. Because these grafts quickly grip and present antigenic lower potential, compared with other treatments used. The purpose of this study was to evaluate the histoarchitecture of human skin grafts irradiated with doses 25 kGy, 50 kGy and non-irradiated during the repair tissue process in nude mice submitted by skin grafting in the dorsal region. Three groups of animals received irradiated human skin grafts (25 kGy and 50 kGy) and non-irradiated and were euthanized on the 3{sup rd}, 7{sup th} and 21{sup th} day after the surgery. Indeed, routine histologic procedures, tissue samples were stained with hematoxylin and eosin (HE) for quantification of keratinocytes, fibroblasts, immune cells and blood vessels and immunofluorescence (IF) was performed to determine the expression human collagen type I and collagen type I and III mouse. Therefore, quantification of both the cells and the collagen types was performed by image analysis using Image-Pro Plus 6.0 software. Histologic results demonstrated at a dose of 25 kGy that human skin irradiation when grafted influences the increase in the number of cells in wound site over time and it provides better dispersion of these cells. In addition, on the 21{sup st} day, three groups of animals with human skin graft were embedded part of the graft in the healing process. On the other hand, the group not irradiated showed greater incorporation of the graft (43 %), but less production of collagen type III mouse (22 %). Since the groups irradiated skin graft showed lower graft incorporation (6 and 15%), but with greater production of collagen type III mice (35 % and 28 % to 25 kGy and 50 kGy, respectively). In conclusion, this study presented that the group irradiated to 25 kGy and it has a higher cell proliferation and vessel formation, and better remodeling of the healing area. (author)

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

Abaca/polyester nonwoven fabric functionalization for metal ion adsorbent synthesis via electron beam-induced emulsion grafting

International Nuclear Information System (INIS)

Madrid, Jordan F.; Ueki, Yuji; Seko, Noriaki

2013-01-01

A metal ion adsorbent was developed from a nonwoven fabric trunk material composed of both natural and synthetic polymers. A pre-irradiation technique was used for emulsion grafting of glycidyl methacrylate (GMA) onto an electron beam irradiated abaca/polyester nonwoven fabric (APNWF). The dependence of degree of grafting (Dg), calculated from the weight of APNWF before and after grafting, on absorbed dose, reaction time and monomer concentration were evaluated. After 50 kGy irradiation with 2 MeV electron beam and subsequent 3 h reaction with an emulsion consisting of 5% GMA and 0.5% polyoxyethylene sorbitan monolaurate (Tween 20) surfactant in deionized water at 40 °C, a grafted APNWF with a Dg greater than 150% was obtained. The GMA-grafted APNWF was further modified by reaction with ethylenediamine (EDA) in isopropyl alcohol at 60 °C to introduce amine functional groups. After a 3 h reaction with 50% EDA, an amine group density of 2.7 mmole/gram adsorbent was achieved based from elemental analysis. Batch adsorption experiments were performed using Cu 2+ and Ni 2+ ions in aqueous solutions with initial pH of 5 at 30 °C. Results show that the adsorption capacity of the grafted adsorbent for Cu 2+ is four times higher than Ni 2+ ions. - Highlights: • An amine type adsorbent from abaca/polyester nonwoven fabric was synthesized. • Pre-irradiation method was used in grafting glycidyl methacrylate on nonwoven fabric. • Radiation-induced grafting was performed with monomer in emulsion state. • The calculated adsorption capacity for Cu 2+ is four times higher than Ni 2+ ions. • Grafted adsorbent can remove Cu 2+ faster than a chemically similar commercial resin

Irradiation inhibits vascular anastomotic stenosis in a canine model

International Nuclear Information System (INIS)

Saito, Takeshi; Iguchi, Atsushi; Tabayashi, Koichi

2009-01-01

The graft patency rate after coronary artery bypass grafting (CABG) correlates with anastomotic stenosis. Intracoronary radiation therapy is effective for preventing restenosis after percutaneous coronary intervention (PCI). We postulated that intracoronary radiation therapy could prevent anastomotic stenosis and tested this hypothesis in an animal model. Femoral arteries and veins of beagle dogs were harvested, and composite arterioarterial and arteriovenous grafts were prepared. After external irradiation of the anastomotic sites, these composite grafts were transplanted into femoral arteries. Histomorphometric and immunohistological analyses of the anastomotic sites were performed. The study groups consisted of controls and animals exposed to 10 Gy, 20 Gy, and 30 Gy (n=5, in each group). In the artery graft model, the ratio of negative remodeling was significantly increased in all groups exposed to ≥10 Gy. The ratio of neointimal hyperplasia was significantly decreased in all groups exposed to ≥10 Gy. Cell density of anti-α-actin antibody-positive cells and anti-proliferating cell nuclear antigen (PCNA) antibody-positive cells was highest in the adventitial layer, and the density decreased as the dosage increased. Experimental results were almost the same in the vein graft models as in the artery graft models. With double immunohistostaining, the anti-PCNA antibody-positive cells expressed α-actin. Irradiation can inhibit anastomotic stenosis in a canine model. Adventitia is a factor in the creation of stenosis, and irradiation appears to target the adventitia. We speculate that there might be a possible role for intracoronary irradiation in the future to prevent anastomotic stenosis. (author)

Radiation induced grafting of tetrafluoroethylene on Nafion Films for ion exchange membrane application

International Nuclear Information System (INIS)

Geraldes, Adriana Napoleao; Silva, Dionisio Furtunato da; Ferreto, Helio Fernando Rodrigues; Souza, Camila Pinheiro; Parra, Duclerc Fernandes; Lugao, Ademar Benevolo

2011-01-01

Grafting of TFE nanocomposites onto Nafion was studied for synthesis of ion exchange membranes. Radiation-induced grafting of TFE gas onto Nafion films was investigated after simultaneous irradiation using a 60 Co source. The thermal degradation of polytetrafluoroethylene (PTFE) waste has been used for production of TFE. Nafion films were irradiated at 15 kGy dose at room temperature and chemical changes were monitored after contact with TFE gas for grafting. The modified films were evaluated by differential scanning calorimetry analysis (DSC), thermogravimetric analysis (TG), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Characterization by XRD suggests crystallinity changes after TFE grafting. The ion exchange capacity (IEC) of membranes was determined by acid-base titration and the values for modified films were achieved similar to Nafion pristine films. DSC measurements revealed a displacement in the endothermic peaks and it was probably associated with the TFE graft. The graft forces the Nafion polymer chains to re-organize themselves and form a more cross-linked structure within the clusters. (author)

Radiation induced grafting of tetrafluoroethylene on Nafion Films for ion exchange membrane application

Energy Technology Data Exchange (ETDEWEB)

Geraldes, Adriana Napoleao; Silva, Dionisio Furtunato da; Ferreto, Helio Fernando Rodrigues; Souza, Camila Pinheiro; Parra, Duclerc Fernandes; Lugao, Ademar Benevolo [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-07-01

Grafting of TFE nanocomposites onto Nafion was studied for synthesis of ion exchange membranes. Radiation-induced grafting of TFE gas onto Nafion films was investigated after simultaneous irradiation using a {sup 60}Co source. The thermal degradation of polytetrafluoroethylene (PTFE) waste has been used for production of TFE. Nafion films were irradiated at 15 kGy dose at room temperature and chemical changes were monitored after contact with TFE gas for grafting. The modified films were evaluated by differential scanning calorimetry analysis (DSC), thermogravimetric analysis (TG), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Characterization by XRD suggests crystallinity changes after TFE grafting. The ion exchange capacity (IEC) of membranes was determined by acid-base titration and the values for modified films were achieved similar to Nafion pristine films. DSC measurements revealed a displacement in the endothermic peaks and it was probably associated with the TFE graft. The graft forces the Nafion polymer chains to re-organize themselves and form a more cross-linked structure within the clusters. (author)

Radiation-grafted membranes based on polyethylene for direct methanol fuel cells

Energy Technology Data Exchange (ETDEWEB)

Sherazi, Tauqir A. [Department of Chemistry, Government College University, Lahore 54000 (Pakistan); Institute for Chemical Process and Environmental Technology, National Research Council Canada, 1200 Montreal Road, Ottawa, ON K1A 0R6 (Canada); Guiver, Michael D.; Kingston, David; Xue, Xinzhong [Institute for Chemical Process and Environmental Technology, National Research Council Canada, 1200 Montreal Road, Ottawa, ON K1A 0R6 (Canada); Ahmad, Shujaat [PIEAS/PINSTECH, P O Nilore, Islamabad 45650 (Pakistan); Kashmiri, M. Akram [Department of Chemistry, Government College University, Lahore 54000 (Pakistan); Board of Intermediate and Secondary Education, Lahore 54000 (Pakistan)

2010-01-01

Styrene was grafted onto ultrahigh molecular weight polyethylene powder (UHMWPE) by gamma irradiation using a {sup 60}Co source. Compression moulded films of selected pre-irradiated styrene-grafted ultrahigh molecular weight polyethylene (UHMWPE-g-PS) were post-sulfonated to the sulfonic acid derivative (UHMWPE-g-PSSA) for use as proton exchange membranes (PEMs). The sulfonation was confirmed by X-ray photoelectron spectroscopy (XPS). The melting and flow properties of UHMWPE and UHMWPE-g-PS are conducive to forming homogeneous pore-free membranes. Both the ion conductivity and methanol permeability coefficient increased with degree of grafting, but the grafted membranes showed comparable or higher ion conductivity and lower methanol permeability than Nafion {sup registered} 117 membrane. One UHMWPE-g-PS membrane was fabricated into a membrane-electrode assembly (MEA) and tested as a single cell direct methanol fuel cell (DMFC). Low membrane cost and acceptable fuel cell performance indicate that UHMWPE-g-PSSA membranes could offer an alternative approach to perfluorosulfonic acid-type membranes for DMFC. (author)

Usefulness of blood irradiation before transfusion to avoid transfusion associated graft versus host disease (TA-GVHD)

International Nuclear Information System (INIS)

Takahashi, Koki

1997-01-01

We summarize the pathology of the transfusion associated graft versus host disease (TA-GVHD) and examine the usefulness of the blood irradiation before transfusion as more widely used prophylaxis. The symptom of TA-GVHD was as follows: after (asymptomatic phase) for 1 to 2 weeks after blood transfusion, pyrexia and erythema appeared. Furthermore, hepatic disorder, diarrhea and bloody stool occurred. In no longer time, pancytopenia by aplastic crisis of the bone marrow appeard, and severe granulocytopenia occurred. Finally, by the complication with severe infectious disease such as septicemia, almost all the patients died with in 3 to 4 weeks after blood transfusion. TA-GVHD was found in some patients without immune deficiency syndrome. The cause of the frequent occurrence of the disease in Japan was shown by the probability of the one-way matching analysis. As the countermeasure of TA-GVHD, we examined the effectiveness of the blood irradiation before transfusion under the consideration of the safety and the emergency. After the responder cells were beforehand irradiated with various doses of radiation (X-ray or g-ray), the proliferative response was investigated through the uptake of 3 H-thymidine, and we obtained 15-50 Gy as the optimum dose of the radiation. We discuss the establishment of the countermeasure for the TA-GVHD and the formation of the nationwide support system for TV-GVHD (K.H.). 33 refs

Reexamination of the role of Lyt-2-positive T cells in murine skin graft rejection

International Nuclear Information System (INIS)

LeFrancois, L.; Bevan, M.J.

1984-01-01

The authors have investigated which T cell subclass defined by cytolysis with monoclonal anti-Lyt-1.2 and anti-Lyt-2.2 antibodies is required to adoptively transfer the ability to reject skin grafts. B6.Thy-1.1 spleen cells immune to graft antigens were fractionated with antibody plus C' and transferred to adult thymectomized, irradiated, bone marrow-reconstituted (ATXBM) B6.Thy-1.2 hosts that were simultaneously grafted with BALB.B skin. The authors found that when the ATXBM hosts were used 6 wk after irradiation and marrow reconstitution, both Lyt-1-depleted and Lyt-2-depleted immune spleen cells could transfer the ability to promptly reject skin grafts. However, such ATXBM recipients of Lyt-2-depleted cells that had rejected skin grafts were found to contain graft-specific CTL that were largely of host (B6.Thy-1.2) origin. When ATXBM hosts were used for the experiment 1 wk after irradiation and marrow reconstitution, no host-derived graft-specific CTL could be detected. However, graft rejection occurred in recipients of anti-Lyt-1- or anti-Lyt-2 plus C'-treated immune cells and specific CTL were generated from spleen cells of both groups. Thus, in the absence of a host-derived response, adoptively transferred immune Lyt-2+ cells, either resistant to, or that escaped from, antibody plus C' treatment, are able to expand in response to the antigenic stimulus provided by the graft. A more complete elimination of specific T cell subclasses is therefore needed to assess the relative contribution of a particular subset to the graft rejection process

Graft polymerization using radiation-induced peroxides and application to textile dyeing

Energy Technology Data Exchange (ETDEWEB)

Enomoto, Ichiro, E-mail: enomoto.ichiro@iri-tokyo.j [Tokyo Metropolitan Industrial Technology Research Institute, KFC Bldg., 12F, 1-6-1, Yokoami, Sumida-ku, Tokyo 130-0015 (Japan); School of Engineering, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Katsumura, Yosuke [School of Engineering, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata Shirane, Tokai-mura, Ibaraki 319-1195 (Japan); Kudo, Hisaaki [School of Engineering, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Soeda, Shin [Tokyo Metropolitan Industrial Technology Research Institute, KFC Bldg., 12F, 1-6-1, Yokoami, Sumida-ku, Tokyo 130-0015 (Japan)

2011-02-15

To improve the dyeing affinity of ultra high molecular weight polyethylene (UHMWPE) fiber, surface treatment by radiation-induced graft polymerization was performed. Methyl methacrylate (MMA), acrylic acid (AA) and styrene (St) were used as the monomers. The grafting yields as a function of storage time after irradiation were examined. Although the grafting yield of St after the sulfonation processing was quite low compared with those of MMA and AA, it was successfully dyed to a dark color with a cationic dye. Some acid dyes can dye the grafted fiber with AA. The acid dye is distributed to the amorphous domains of the AA grafted fiber. The dyeing concentration depended on the grafting yield, and the higher the grafting yield the darker the dye color.

Graft polymerization using radiation-induced peroxides and application to textile dyeing

International Nuclear Information System (INIS)

Enomoto, Ichiro; Katsumura, Yosuke; Kudo, Hisaaki; Soeda, Shin

2011-01-01

To improve the dyeing affinity of ultra high molecular weight polyethylene (UHMWPE) fiber, surface treatment by radiation-induced graft polymerization was performed. Methyl methacrylate (MMA), acrylic acid (AA) and styrene (St) were used as the monomers. The grafting yields as a function of storage time after irradiation were examined. Although the grafting yield of St after the sulfonation processing was quite low compared with those of MMA and AA, it was successfully dyed to a dark color with a cationic dye. Some acid dyes can dye the grafted fiber with AA. The acid dye is distributed to the amorphous domains of the AA grafted fiber. The dyeing concentration depended on the grafting yield, and the higher the grafting yield the darker the dye color.

Blood irradiation: Rationale and technique

International Nuclear Information System (INIS)

Lewis, M.C.

1990-01-01

Upon request by the local American Red Cross, the Savannah Regional Center for Cancer Care irradiates whole blood or blood components to prevent post-transfusion graft-versus-host reaction in patients who have severely depressed immune systems. The rationale for blood irradiation, the total absorbed dose, the type of patients who require irradiated blood, and the regulations that apply to irradiated blood are presented. A method of irradiating blood using a linear accelerator is described

Development of an amine-type adsorbent by electron beam-induced emulsion grafting of glycidyl methacrylate onto a nonwoven fabric

International Nuclear Information System (INIS)

Madrid, Jordan; Ueki, Yuji; Seko, Noriaki

2013-01-01

In the recent years, radiation-induced graft polymerization of various monomers onto different types of trunk polymers have been extensively used for researchers on adsorbents for cations, anions and different compounds, battery separators, antibacterial bandages, protein separators, and fuel cell applications. Some of these technologies were transferred to end-users and eventually commercialized. In most of these studies, a post-grafting reaction is performed to introduced chemical groups that impart functionality to the grafted material. In this paper, pre-irradiation technique was used for emulsion grafting of glycidyl methacrylate (GMA) onto an electron beam irradiated abaca-polyester nonwoven fabric (APNWF). The dependence of degree of grafting (Dg), calculated from the weight of APNWF before and after grafting, on irradiation dose, reaction time and monomer concentration were studies. After 50 kGy irradiation with 2 MeV electron beam and subsequent 3-hour reaction with an emulsion consisting of 5% GMA and 0.5% polyoxyethylene sorbitan monolaurate (Tween 20) surfactant in deionized water at 40 degree centegrade, a grafted APNWF with a Dg greater than 150% was obtained. The GMA grafted APNWF was further modified by reaction with ethylenediamine (EDA) in isopropyl alcohol at 60 degree centegrade to introduce amine functional groups. A 3-hour reaction with 50% EDA resulted to an amine group density of 2.7 mmole/gram-adsorbent. Preliminary batch adsorption experiments using Cu 2+ and Ni 2+ ions in aqueous solutions show that the adsorption capacity of the grafted adsorbent is four times greater for Cu 2+ ions compared to Ni 2+ ions. (author)

Evaluation of absorbed dose-distribution in the X-ray or gamma-irradiator for blood products

International Nuclear Information System (INIS)

Moriyama, Satoshi; Kurihara, Katsuhiko; Yokokawa, Nobuhiko; Satake, Masahiro; Juji, Takeo

2001-01-01

Irradiation of blood products abrogates the proliferation of lymphocytes present in cellular component, which is currently the only accepted methodology to prevent transfusion-associated graft versus host disease (TA-GVHD). A range of irradiation dose levels between 15 Gy and 50 Gy is being used, but the majority of facilities are employing 15 Gy. It should, however, be recognized that the delivered dose in the instrument canister might differ from the actual dose absorbed by the blood bag. This study have evaluated the actual dose distribution under practical conditions where a container was loaded with blood products or water bags, or filled with distilled water. This approach provides data that the maximum attenuation occurred when the container was completely filled with a blood-compatible material. Thus, an error of approximately 20 percent should be considered in the dose measured in the in-air condition. A dose calibration in an in-air condition may lead to substantial underexposure of the blood products. A dose distribution study using adequately prearranged exposure period verified that the absorbed dose of 15 Gy was attained at any point in the container for both linear accelerator and gamma-irradiator. The maximal difference in the absorbed dose between measured points was 1.5- and 1.6-fold for linear accelerator and gamma-irradiator, respectively. In conclusion, using blood-compatible materials, a careful dose calibration study should be employed in which the absorbed dose of 15 Gy is obtained at the point where the lowest dose could be expected. (author)

Modification on liquid retention property of cassava starch by radiation grafting with acrylonitrile: Pt. 1

International Nuclear Information System (INIS)

Kiatkamjornwong, S.; Nakason, C.; Chvajarempun, J.

1993-01-01

Radiation modification on liquid retention properties of native cassava starch, gelatinized at 85 o C, by graft copolymerization with acrylonitrile was carried out by mutual irradiation to gamma-rays. A thin aluminium foil was used to cover the inner wall of the reaction vessel, so that the homopolymer concentration was reduced to be less than 1.0% with a distilled water retention value of 665 g/g of the dry weight of the saponified grafted product. Confirmation of graft copolymerization and saponification reactions was made by the infrared spectrophotometric technique. The combined effect of radiation parameters in terms of an irradiation time and a dose rate to the total dose on the extent of the grafting reaction expressed in terms of grafting parameters which directly influenced liquid retention values was evaluated in conjunction with statistical analysis. (author)

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

Ionic membranes obtained by radiation-induced graft copolymerization, I-preparation. Vol. 3

Energy Technology Data Exchange (ETDEWEB)

Abd El-Rehim, H A; Hegazy, E A [National Center for Radiation and Technology, Atomic Energy Authority, Cairo, (Egypt); Ali, A M.I.; Nowier, H G; Aly, H F [Hot Laboratories Center, atomic Energy Authority, Cairo, (Egypt)

1996-03-01

A study has been made on the preparation of ionic membranes by radiation-induced graft copolymerization of acrylic acid (AAC) onto low density polyethylene (LDPE) films. The Suitable conditions at which the grafting proceeds homogeneously were determined. To minimize the homo polymerization of AAC during irradiation process different types of inhibitors were investigated to find that the addition of Fe Cl{sub 3} (1.5 Wt%) effectively reduced such process when compared with other inhibitors used. The suitable diluent for this grafting system is found to be distilled water, methanol and methanol water mixture. The effect of diluent mixture composition, irradiation time, addition of mineral or organic acid and metal chlorides on the grafting yield and its homogeneity in the graft copolymer was determined. It was observed that the grafting yield increased as the content of water increased in MeOH/H{sub 2} O mixture. The addition of oxalic acid to the reaction medium enhanced the grafting process, however, the addition of HCl or H{sub 2} S O{sub 4} resulted in a more homogeneous grafting. The same effect was also observed when metal salts; namely N H{sub 4} Cl, NaCl and Cu Cl{sub 2} were added and resulted in homogeneous grafted membranes. The swelling and permeability of the grafted films prepared were also investigated. Results obtained in this study showed a great promise for the possible practical use of such prepared graft copolymers as a good hydrophilic membrane. The possibility of its use as an ion-exchange membrane for metal waste will be considered.4 figs., 5 tabs.

Differentiation of bone marrow cells to functional T lymphocytes following implantation of thymus grafts and thymic stroma in nude and ATxBM mice

International Nuclear Information System (INIS)

Splitter, G.A.; McGuire, T.C.; Davis, W.C.

1977-01-01

Cardiac allografts were used to compare the immunologic capacity of nude mice and adult, thymectomized, lethally irradiated, bone marrow-reconstituted (AT x BM) mice. Neither nude nor AT x BM mice were able to reject cardiac allografts of any party. However, both rejected grafts of any party following implantation of neonatal thymus or thymus from 3-week-old syngeneic mice. Irradiated syngeneic thymus grafts (800 R) were equally effective in restoring host responsiveness against allografts. In contrast, allogeneic thymus grafts restored the capacity to reject second-party heart grafts only in AT x BM mice. Second-party grafts persisted indefintely when placed on nude mice implanted with an allogeneic, unirradiated thymus graft. Third-party grafts transplanted 17 weeks after reconstitution, however, were rejected. Irradiated nude mice given normal littermate bone marrow and simultaneously grafted with second-party thymus and heart allografts also failed to reject their second-party heart grafts. The difference in ultimate capacity to respond between AT x BM and nude mice suggests that a maturational defect exists in the nude mouse environment which impedes development of precursor T lymphocytes

Synthesis of ion-exchange membranes by radiation-induced multiple grafting of methyl α,β,β-trifluoroacrylate

International Nuclear Information System (INIS)

Omichi, H.; Okamoto, J.

1982-01-01

Methyl α,β,β-trifluoroacrylate (MTFA) was grafted onto polymer films with the multiple grafting technique initiated by γ-rays: the yields were similar to those of the single-step grafting procedure with any irradiation dose. Grafted polymer obtained in the single-step experiments were distributed mainly near the film surface, whereas graft polymer from the multiple grafting experiments were distributed uniformly in the film at graft yields greater than 20%. The electric resistance of the hydrolyzed multiple graft polymer film in a 2N NaOH solution was much lower than that of one-step graft film at the same graft yield

Abaca/polyester nonwoven fabric functionalization for metal ion adsorbent synthesis via electron beam-induced emulsion grafting

Science.gov (United States)

Madrid, Jordan F.; Ueki, Yuji; Seko, Noriaki

2013-09-01

A metal ion adsorbent was developed from a nonwoven fabric trunk material composed of both natural and synthetic polymers. A pre-irradiation technique was used for emulsion grafting of glycidyl methacrylate (GMA) onto an electron beam irradiated abaca/polyester nonwoven fabric (APNWF). The dependence of degree of grafting (Dg), calculated from the weight of APNWF before and after grafting, on absorbed dose, reaction time and monomer concentration were evaluated. After 50 kGy irradiation with 2 MeV electron beam and subsequent 3 h reaction with an emulsion consisting of 5% GMA and 0.5% polyoxyethylene sorbitan monolaurate (Tween 20) surfactant in deionized water at 40 °C, a grafted APNWF with a Dg greater than 150% was obtained. The GMA-grafted APNWF was further modified by reaction with ethylenediamine (EDA) in isopropyl alcohol at 60 °C to introduce amine functional groups. After a 3 h reaction with 50% EDA, an amine group density of 2.7 mmole/gram adsorbent was achieved based from elemental analysis. Batch adsorption experiments were performed using Cu2+ and Ni2+ ions in aqueous solutions with initial pH of 5 at 30 °C. Results show that the adsorption capacity of the grafted adsorbent for Cu2+ is four times higher than Ni2+ ions.

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)

The role of hydroperoxides as a precursor in the radiation-induced graft polymerization of methyl methacrylate to ultra-high molecular weight polyethylene

Energy Technology Data Exchange (ETDEWEB)

Enomoto, Ichiro, E-mail: enomoto.ichiro@iri-tokyo.j [Tokyo Metropolitan Industrial Technology Research Institute, KFC bldg., 12F, 1-6-1, Yokoami, Sumida-ku, Tokyo 130-0015 (Japan); School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Katsumura, Yosuke [School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata Shirane, Tokai-mura, Ibaraki 319-1195 (Japan); Kudo, Hisaaki [School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Sekiguchi, Masayuki [Tokyo Metropolitan Industrial Technology Research Institute, KFC bldg., 12F, 1-6-1, Yokoami, Sumida-ku, Tokyo 130-0015 (Japan)

2010-06-15

A graft polymerization of methyl methacrylate (MMA) to ultra-high molecular weight polyethylene (UHMWPE) with Co-60 gamma-ray irradiation in air at room temperature has been carried out. The grafting yields were measured as a function of the storage time (elapsed time from the end of irradiation to the start of grafting), and it was found that the yields reach at the maximum values at around several days since the end of irradiation. In order to clarify the precursor of the graft polymerization, changes of the radical yields and the carbonyl groups were measured as a function of storage time with ESR and microscopic FT-IR, respectively. From the similarities between the depth profiles of the hydroperoxide formation and the grafting products, it was concluded that the hydroperoxides can be main precursors of the grafting of the radiation-induced polymerization of MMA to UHMWPE under the given conditions.

The role of hydroperoxides as a precursor in the radiation-induced graft polymerization of methyl methacrylate to ultra-high molecular weight polyethylene

International Nuclear Information System (INIS)

Enomoto, Ichiro; Katsumura, Yosuke; Kudo, Hisaaki; Sekiguchi, Masayuki

2010-01-01

A graft polymerization of methyl methacrylate (MMA) to ultra-high molecular weight polyethylene (UHMWPE) with Co-60 γ-ray irradiation in air at room temperature has been carried out. The grafting yields were measured as a function of the storage time (elapsed time from the end of irradiation to the start of grafting), and it was found that the yields reach at the maximum values at around several days since the end of irradiation. In order to clarify the precursor of the graft polymerization, changes of the radical yields and the carbonyl groups were measured as a function of storage time with ESR and microscopic FT-IR, respectively. From the similarities between the depth profiles of the hydroperoxide formation and the grafting products, it was concluded that the hydroperoxides can be main precursors of the grafting of the radiation-induced polymerization of MMA to UHMWPE under the given conditions.

Modification of flax fibres by radiation induced emulsion graft copolymerization of glycidyl methacrylate

International Nuclear Information System (INIS)

Moawia, Rihab Musaad; Nasef, Mohamed Mahmoud; Mohamed, Nor Hasimah; Ripin, Adnan

2016-01-01

Flax fibres were modified by radiation induced graft copolymerization of glycidyl methacrylate (GMA) by pre-irradiation method in an emulsion medium. The effect of reaction parameters on the degree of grafting (DOG) such as concentration of bleaching agent, absorbed dose, monomer concentration, temperature and reaction time were investigated. The DOG was found to be dependent on the investigated parameters. The incorporation of poly(GMA) grafts in the bleached flax fibres was confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The structural and mechanical changes were evaluated by X-ray diffraction (XRD) and mechanical tester, respectively. The results revealed that reacting bleached flax fibres irradiated with 20 kGy with 5% GMA emulsion containing 0.5% polyoxyethylene-sorbitan monolaurate (Tween 20) surfactant at 40 °C for 1 h led to a maximum DOG of 148%. The grafted fibres showed sufficient mechanical strength and hydrophobicity which make them promising precursors for development of adsorbents after appropriate chemical treatments. - Highlights: • Flax fibers were modified by radiation induced emulsion grafting of GMA. • Bleaching with 0.7 wt% Na-chlorite was essential for achieving high DOGs. • Effect of reaction parameters on the degree of grafting were established. • The incorporation of poly-GMA grafts was proved by SEM, FTIR and XRD. • The obtained poly-GMA grafted flax fibers have potential for adsorbent making.

Effect of gamma rays on grafting parameters and liquid retention property of cassava starch-g-PAN

International Nuclear Information System (INIS)

Kiatkamjornwong, S.; Chvajarernpun, J.; Nakason, C.

1992-01-01

Radiation modification on liquid retention properties of native cassava starch, gelatinized at 85 0 C, by graft copolymerization with acrylonitrile was carried out by mutual irradiation to γ-rays. A thin aluminium foil was used to cover the inner wall of the reaction vessel so that the extent of homo polymer could be reduced to be less than 1.6% with a distilled water retention value of 665 g/g of the dry weight of the saponified grafted product. Confirmations of graft copolymerization and saponification reactions were made by the infrared spectrophotometric technique. The combined effect of radiation parameters in terms of an irradiation time and a dose rate to the same total dose on the extent of grafting reaction expressed in terms of grafting parameters which directly influenced liquid retention values was evaluated in conjunction with statistical analysis

Effects of Electron Beam Irradiation on Binary Polyamide-6 Blends with Metallocene Copolymers

International Nuclear Information System (INIS)

Rosales, C.

2006-01-01

A versatile way to produce new materials with high Izod impact strength and reduced heat deformations is the irradiation of compatibilized blends. The effect of electron beam irradiation and different types of dispersed phase grafted copolymers on thermal and mechanical properties, and SEM morphology of polyamide-6 (PA-6) blends were investigated. Two metallocene copolymers (mEPDM and mPOE) grafted in-situ with maleic anhydride and two commercial maleated copolymers (EPDM-g-MA and mEPR-g-MA) were employed in binary blends with PA6 as matrix. The blends were prepared by extrusion with a composition of 80 wt. % of PA-6. The influence of the radical or functional groups generated in the grafting and the irradiation processes (25, 50, 100 and 200 kGy) was found by ATR-FTIR. The blends exhibited the characteristic thermal behavior of immiscible systems. All compatibilizers employed influenced the melting and crystallization behavior of the blend components without irradiation and an improvement in interface adhesion was clearly observed by SEM micrographs. The sizes of the dispersed phase in the non-irradiated reactive blends were in agreement with the viscosity ratios of the blend components. High toughness materials were obtained with ethylene-polypropylene-diene (mEPDM) grafted copolymers without significant variations in their thermal properties and Izod impact strength at room temperature and -30 degree with the irradiation doses. However, the toughness of the blends with grafted metallocene polyethylenes was affected by the irradiation doses employed. Therefore, the gel content and tensile properties of the samples depended on the chain scission, crosslinking and/or grafting reactions of the blend components

Protection of lethally irradiated mice with allogeneic fetal liver cells: influence of irradiation dose on immunologic reconstitution

International Nuclear Information System (INIS)

Tulunay, O.; Good, R.A.; Yunis, E.J.

1975-01-01

After lethal irradiation long-lived, immunologically vigorous C3Hf mice were produced by treatment with syngeneic fetal liver cells or syngeneic newborn or adult spleen cells. Treatment of lethally irradiated mice with syngeneic or allogeneic newborn thymus cells or allogeneic newborn or adult spleen cells regularly led to fatal secondary disease or graft-versus-host reactions. Treatment of the lethally irradiated mice with fetal liver cells regularly yielded long-lived, immunologically vigorous chimeras. The introduction of the fetal liver cells into the irradiated mice appeared to be followed by development of immunological tolerance of the donor cells. The findings suggest that T-cells at an early stage of differentiation are more susceptible to tolerance induction than are T-lymphocytes at later stages of differentiation. These investigations turned up a perplexing paradox which suggests that high doses of irradiation may injure the thymic stroma, rendering it less capable of supporting certain T-cell populations in the peripheral lymphoid tissue. Alternatively, the higher and not the lower dose of irradiation may have eliminated a host cell not readily derived from fetal liver precursors which represents an important helper cell in certain cell-mediated immune functions, e.g., graft-versus-host reactions, but which is not important in others, e.g., allograft rejections. The higher dose of lethal irradiation did not permit development or maintenance of a population of spleen cells that could initiate graft-versus-host reactions but did permit the development of a population of donor cells capable of achieving vigorous allograft rejection

Radiation graft post-polymerization of sodium styrene sulfonate onto polyethylene

International Nuclear Information System (INIS)

Kitaeva, N.K.; Duflot, V.R.; Ilicheva, N.S.

2013-01-01

Post-irradiation grafting of sodium styrene sulfonate (SSS) in the presence of acrylic acid (AA) has been investigated on polyethylene (PE) pre-exposed to gamma radiation at room temperature in the air. Special attention was paid to the effect of low molecular weight salt additives on the kinetics of graft copolymerization of SSS and AA. The presence of SSS links in the grafted PE copolymers was detected by the methods of UV and FTIR spectroscopy. Based on the FTIR spectroscopy and element analysis data, a mechanism was proposed for graft copolymerization of SSS and AA onto PE. The mechanical properties of the graft copolymers were studied. It was established that PE copolymers grafted with sulfonic acid and carboxyl groups have higher strength characteristics (16.3 MPa) compared to the samples containing only carboxyl groups (11 MPa). (author)

Graft-versus-host reaction in small bowel transplantation and possibilities for its circumvention

International Nuclear Information System (INIS)

Deltz, E.; Ulrichs, K.; Schack, T.; Friedrichs, B.; Mueller-Ruchholtz, W.M.; Mueller-Hermelink, H.K.T.; Thiede, A.

1986-01-01

To describe GVHR in small bowel transplantation and its underlying mechanisms and to find methods for circumventing that response, accessory small bowel transplantation was carried out in the rat model. Animals not treated with cyclosporine, irradiation, or removal of the mesenteric lymph nodes of the graft died within 22 days postoperatively due to graft versus host disease. Mesenteric lymph nodes of the graft and recipient spleen and peripheral lymph nodes showed strong immunologic stimulation histologically and high antihost T-cell-mediated cytotoxic antihost reactivity. Seventy-one percent of the animals that had received 15 mg of cyclosporine per kilogram body weight orally survived 150 days after transplantation. After donor irradiation with 50 rads, 77 percent of the recipients survived 120 days. After microsurgical removal of the mesenteric lymph nodes of the graft, 89 percent survived 120 days. We conclude that GVHR plays an important role in small bowel transplantation and that the experimental regimens of donor, graft, and recipient treatment described herein have proved their efficacy for circumventing GVHR

Immunological and clinical observations in diabetic kidney graft recipients pretreated with total-lymphoid irradiation

International Nuclear Information System (INIS)

Waer, M.; Vanrenterghem, Y.; Roels, L.

1987-01-01

In a feasibility study, twenty patients with end-stage diabetic nephropathy were treated with fractionated total-lymphoid irradiation (TLI, mean dose 25 Gy), before transplantation of a first cadaveric kidney. During radiotherapy, only one patient had a serious side effect (bone marrow depression). After transplantation four patients died (one of a myocardial infarction, one of ketoacidosis, and two of infections occurring during treatment of rejection crises). One graft was lost because of chronic rejection. The other 15 patients have a functioning graft (mean follow-up 24 months) and receive low-dose prednisone alone (less than 10 mg/day, n = 11) or in conjunction with cyclosporine (n = 4) as maintenance immunosuppressive therapy. A favorable clinical outcome after TLI (no, or only one, steroid-sensitive rejection crisis) was significantly correlated with a high pre-TLI helper/suppressor lymphocyte ratio, a short interval between TLI and the time of transplantation, and the occurrence of functional suppressor cells early after TLI. The most striking immunological changes provoked by TLI consisted of a long-term depression of the mixed lymphocyte reaction and of the phytohemagglutinin, and Concanavalin A or pokeweed-mitogen-induced blastogenesis. A rapid and complete recovery of the natural killer cell activity was observed after TLI. A permanent inversion of the OKT4+ (T helper/inducer) over OKT8+ (T suppressor/cytotoxic) lymphocyte ratio was provoked by a decrease of the OTK4+ subpopulation, together with a supranormal recovery of the OKT8+ lymphocytes. A majority of the latter lymphocytes did also express the Leu 7 and the Leu 15 phenotype

Study of the simultaneous grafting and heparinisation of poly(vinyl chloride), by gamma radiation

International Nuclear Information System (INIS)

Panzarini, Luz Consuelo Gonzalez Alonso

2003-01-01

This work had the objective of obtaining the PVC-co-DMAEMA-co-Heparin graft copolymer through process of simultaneous irradiation by γ-radiation coming from a 60 Co source with dose rate ranging between 0,5 and 0,8 kGy h -1 . Grafting parameters were evaluated in function of PVC film swelling time before irradiation, concentration of hydrophilic N,N-dimethylaminoethyl methacrylate (DMAEMA) monomer, radiation doses ranging between zero and 7,0 kGy, concentration of isopropyl alcohol and CUSO 4 as homopolymerization inhibitors varying from 0,02 mol L -1 to 1,0 mol L -1 . Preliminary studies allowed us to establish the concentration of DMAEMA at 30 and 45%. At these two studied concentrations, were observed the highest grafting levels when was utilized 0,02 mol L -1 concentrations of homopolymerization inhibitor. A study of grafting as a function of the dose showed an interdependence between the dose and DMAEMA concentration, where was achieved the highest grafting level at doses of 2,5 kGy and 5,0 kGy for the systems containing 45% and 30% of DMAEMA, respectively. Graft copolymer characterization, accomplished by Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) evidenced the largest grafting levels for the irradiated samples with 45% of DMAEMA, however heparin presence was only evident on irradiated samples with 30% of DMAEMA. Surface morphological analysis, carried out by scanning electronic microscopy, permitted us to notice that addition of heparin to the reaction medium (0.25% w/v) led to obtaining surfaces less rough than those ones observed in heparin absence, suggesting then a more homogeneous distribution of the graft chains. Evaluation of antithrombogenic properties of the graft copolymers, accomplished 'in vitro' through platelets adhesion test, showed that the increase of surface roughness affects the blood platelet activation mechanisms, leading consequently to a more thrombogenic surface. Analysis by means of electron paramagnetic

Effect of dihydroartemisinin on the cell cycle progress of irradiated human cervical cancer cell line and its mechanism

International Nuclear Information System (INIS)

Chen Xialin; Ji Rong; Cao Jianping; Zhu Wei; Fan Sanjun; Wang Jianfang; Cao Jianping

2010-01-01

Objective: To observe the changes of cell cycle on cancer cells after dihydroartemisinin and X-ray irradiation. Methods: Human HeLa cells of cervical cancer with p53 mutation was used and human SiHa cells of cervical cancer with wild p53 was used as control. Flow cytometry was used to detect the effect of dihydroartemisinin (20 and 100 μmol/L) and irradiation (6 Gy)on cell cycle. Western blot was used to measure the levels of cell cycle protein. Results: G 2 arrest was observed in irradiated HeLa cells, which the proportion of cells in G 2 phase was increased from 14.45% to 73.58% after 6 Gy X-ray irradiation, but it was abrogated by dihydroartemisinin from 73. 58% to 48.31% in HeLa cells, and it had no change on the SiHa cells. The elevated Wee1 protein and the lowered Cyclin B1 protein were observed with the G 2 arrest severity. The expression of radiation-induced Wee1 protein was suppressed and the Cyclin B1 protein was increased after dihydroartemisinin treatment, which was in accordance with the abrogation of radiation-induced G 2 delay. Conclusions: The main effect of irradiation on cell cycle of p53 mutated HeLa cells is G 2 arrest. Dihydroartemisinin could abrogate it, which is associated with the changes of Wee1 protein and Cyclin B1 protein. In Siha cells, the main effect of irradiation on cell cycle is G 1 arrest, and dihydroartemisinin has no effect on it. (authors)

Reactivation of X-irradiated cell material during limb regeneration in Urodeles Amphibians

International Nuclear Information System (INIS)

Desselle, J.C.

1979-10-01

In amputated members irradiated with X-rays the regeneration power is inhibited. This power is restored by grafts of healthy tissue in the irradiated members. The origin of the cell material of the restored regeneration blastema has been studied by an original labelling technique. The different amounts of DNA in the graft cells and those of the stump mark the graft cells during the regeneration process. It was shown that the graft causes a reactivation of the inhibited stump cells and the reactivation stages are the same as the activation stages of the member regenerating normally. It was also established that during restored regeneration the cell material implanted in the irradiated members contributes, by the 160th day of regeneration, 4.5% of the cartilaginous regenerate cells and 12% of the muscle cells. All the other regenerate cells are supplied by the cells of the stump; these are reactivated and together with the activated graft cells lead to the restitution of the amputated member [fr

Functional clonal deletion versus suppressor cell-induced transplantation tolerance in chimeras prepared with a short course of total-lymphoid irradiation

International Nuclear Information System (INIS)

Slavin, S.; Morecki, S.; Weigensberg, M.; Bar, S.; Weiss, L.

1986-01-01

Allogeneic bone marrow (BM) chimeras induced by infusion of BM cells into recipients conditioned with total lymphoid irradiation (TLI) were shown to develop humoral and cell-mediated tolerance to host and donor-type alloantigens by a number of in vitro and in vivo assays. Spleen cells of tolerant chimeras exhibited suppressive activity of mixed lymphocyte reaction (MLR). MLR suppression was not abrogated by depletion of Lyt-2 cells, and neither could Lyt-2-positive cells sorted from the spleens of tolerant chimeras suppress MLR or attenuate graft-versus-host reactivity in vivo. Likewise, specifically unresponsive spleen cells obtained from chimeras could not be induced to respond in MLR against tolerizing host-type cells following depletion of Lyt-2 or passage through a nylon-wool column. Tolerance of chimera spleen cells to host alloantigens, best documented by permanent survival of donor-type skin allografts, could be adoptively transferred into syngeneic recipients treated by heavy irradiation but not into untreated or mildly irradiated recipients. Adoptive transfer of tolerance seemed to be associated with experimental conditions favoring engraftment of tolerant cells rather than suppression of host reactivity. We speculate that although host and/or donor-derived suppressor cells may be operating in reducing the pool of specific alloreactive clones by blocking cell proliferation in response to allogeneic challenge, the final outcome in tolerant chimeras is actual or functional deletion of alloreactive clones

Comparative studies in the cellular immunostimulation by whole body irradiation

International Nuclear Information System (INIS)

Dietz, R.; Schwarze, G.

1992-01-01

The effect of the cellular immune response by total body irradiation was investigated. The transplant survival (skin grafts) was determined as immune parameter. Donors were colony bred Wistar rats and recipients were colony bred Sprague Dawley rats. The investigations were carried out with irradiated rats and with rats irradiated after thymectomy and/or adrenalectomy as well as with animals without irradiation. A single total-body irradiation (1 and 2 Gy) was administered. The skin graft survival in irradiated rats was significant shorter (radiogenic immunostimulation) than in unirradiated rats; there were no significant differences between the operated (thymectomy and/or adrenalectomy) and not operated animals. Including precedent examinations this radiogenic immunostimulation is caused by relativly selective inactivation of T-suppressor cells. (orig.) [de

Preparation of poly(vinyl alcohol) membranes grafted with N-vinyl imidazole/acrylic acid binary monomers

International Nuclear Information System (INIS)

Ajji, Zaki; Ali, Ali

2006-01-01

Poly(vinyl alcohol) films were grafted with two monomers using gamma radiation, acrylic acid and N-vinyl imidazole. The influence of different parameters on the grafting yield was investigated as: type of solvent and solvent composition, comonomer concentration and composition, addition of mineral acids, and irradiation dose. Water uptake in respect to the grafting yield was also evaluated. The ability of the grafted films to adsorb copper ions was elaborated and discussed for different grafting yields and ph values of the solution. (authors)

The effect of irradiation and hydration upon the mechanical properties of tendon

International Nuclear Information System (INIS)

Smith, C.W.; Kearney, J.N.

1996-01-01

Irradiation sterilization is in wide use among tissue banks, for both hard and soft tissue grafts. Irradiation of tendon can impair its mechanical properties. Following implantation of a tendon graft, re-vascularization and resorption processes reduce its mechanical performance. Tendon with severely impaired properties may not be suitable for use as a load-bearing graft, e.g. as anterior cruciate ligament replacement. An important factor determining the extent of the reduction of the mechanical performance is the condition of the tendon during irradiation, especially the presence of water. There has not yet been a study of the effects of both irradiation dose and hydration on tendon mechanical properties. This study measured the changes in tensile mechanical properties, including strength and stiffness, following γ irradiation doses of 15 kGy (1.5 MRad) and 25 kGy irradiated tendons was lower compared to fresh tendons, whereas the strength of the frozen irradiated tendons was very similar to that of the fresh. The tangent modulus of both of the freeze-dried irradiated groups were lower than the fresh tendons, as was the 15 kGy frozen group. The modulus of the 25 kGy frozen irradiated group was similar to the fresh. The general pattern of the results indicate that the two freeze-dried tendon groups were more affected than the frozen irradiated, and of the frozen irradiated groups the 25 kGy group was least affected. The results fit well with suggested mechanisms for the action of irradiation upon collagen; that intramolecular crosslinking and scission of the tropocollagen α chains occur when water is present, and α chain scission alone occurs when water is absent. Irradiation of tendons for use as grafts may produce minimal deleterious changes if the irradiation is performed while the tendon is frozen with water present. (Author)

Modification of flax fibres by radiation induced emulsion graft copolymerization of glycidyl methacrylate

Science.gov (United States)

Moawia, Rihab Musaad; Nasef, Mohamed Mahmoud; Mohamed, Nor Hasimah; Ripin, Adnan

2016-05-01

Flax fibres were modified by radiation induced graft copolymerization of glycidyl methacrylate (GMA) by pre-irradiation method in an emulsion medium. The effect of reaction parameters on the degree of grafting (DOG) such as concentration of bleaching agent, absorbed dose, monomer concentration, temperature and reaction time were investigated. The DOG was found to be dependent on the investigated parameters. The incorporation of poly(GMA) grafts in the bleached flax fibres was confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The structural and mechanical changes were evaluated by X-ray diffraction (XRD) and mechanical tester, respectively. The results revealed that reacting bleached flax fibres irradiated with 20 kGy with 5% GMA emulsion containing 0.5% polyoxyethylene-sorbitan monolaurate (Tween 20) surfactant at 40 °C for 1 h led to a maximum DOG of 148%. The grafted fibres showed sufficient mechanical strength and hydrophobicity which make them promising precursors for development of adsorbents after appropriate chemical treatments.

Research work of radiation induced graft polymerization for synthesis and modification of polymer materials in CRICI

Energy Technology Data Exchange (ETDEWEB)

Hu Fumin; Ma Xueming [Chenguan Research Institute of Chemical Industry, Chengdu (China)

2000-03-01

The direct and post radiation induced graft polymerization had been studied in CRICI (Chenguan Research Institute of Chemical Industry). The method consists of irradiation of various polymer substrates in the presence (or absence) of monomers in a liquid, saturated vapour or gaseous and non-saturated vapour. 1. Grafting of functional monomers. --- It is possible to divide the grafting into two main approaches for synthesis of functional polymer materials. The first is grafting of monomers attached required functional group such as unsaturated carboxylic acid (acrylic and methacrylic acid), unsaturated nitrogen containing (alkali) base (vinylpyridine), monomers with hydrophilic unionized and polar groups (acrylamide, N-vinylpyrrolidone glycidylmethacrylate) and so on. The second is grafting of monomers capable of continuing chemical modification after graft polymerization. This approach essentially expands synthetic possibility of RGP for preparing functional polymers. 2. The effect of some salts on aqueous solution graft polymerization. The grafting of AA or AAm onto PE by direct or post radiation method in the presence of Mohr's salt or cupric nitrate was studied in detail. 3. Radiation induced graft polymerization by gaseous phase of monomers. This method consists of irradiation or preirradiation of various polymer substrates in the presence (or absence for preirradiation) of monomer in a gaseous of nonsaturated vapour state. (J.P.N.)

Research work of radiation induced graft polymerization for synthesis and modification of polymer materials in CRICI

International Nuclear Information System (INIS)

Hu Fumin; Ma Xueming

2000-01-01

The direct and post radiation induced graft polymerization had been studied in CRICI (Chenguan Research Institute of Chemical Industry). The method consists of irradiation of various polymer substrates in the presence (or absence) of monomers in a liquid, saturated vapour or gaseous and non-saturated vapour. 1. Grafting of functional monomers. --- It is possible to divide the grafting into two main approaches for synthesis of functional polymer materials. The first is grafting of monomers attached required functional group such as unsaturated carboxylic acid (acrylic and methacrylic acid), unsaturated nitrogen containing (alkali) base (vinylpyridine), monomers with hydrophilic unionized and polar groups (acrylamide, N-vinylpyrrolidone glycidylmethacrylate) and so on. The second is grafting of monomers capable of continuing chemical modification after graft polymerization. This approach essentially expands synthetic possibility of RGP for preparing functional polymers. 2. The effect of some salts on aqueous solution graft polymerization. The grafting of AA or AAm onto PE by direct or post radiation method in the presence of Mohr's salt or cupric nitrate was studied in detail. 3. Radiation induced graft polymerization by gaseous phase of monomers. This method consists of irradiation or preirradiation of various polymer substrates in the presence (or absence for preirradiation) of monomer in a gaseous of nonsaturated vapour state. (J.P.N.)

Radiation-grafting of acrylamide onto silicone rubber films for diclofenac delivery

Science.gov (United States)

Magaña, Hector; Palomino, Kenia; Cornejo-Bravo, Jose M.; Alvarez-Lorenzo, Carmen; Concheiro, Angel; Bucio, Emilio

2015-02-01

This work focuses on the pre-irradiation grafting of acrylamide (AAm) onto silicone rubber films (SR) and evaluates the effect of gamma-ray radiation conditions on the grafting yield, which in turn may influence the performance of the grafted materials as components of drug-eluting devices. Pristine and modified SR were characterized using FTIR-ATR, DSC, TGA, swelling, and water contact angle analysis in order to elucidate the effects of AAm grafting onto SR. Grafted films with content in AAm ranging from 0.81% to 22.20% showed excellent cytocompatibility against fibroblasts, and capability to uptake the anti-inflammatory drug diclofenac. Amount of drug loaded directly correlated with the grafting degree of the films. Drug release studies were performed at pH 7.4 and 37 °C (physiological conditions). Most grafted films released the drug in a sustained way for at least three hours.

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)

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)

Total lymphoid irradiation

International Nuclear Information System (INIS)

Sutherland, D.E.; Ferguson, R.M.; Simmons, R.L.; Kim, T.H.; Slavin, S.; Najarian, J.S.

1983-01-01

Total lymphoid irradiation by itself can produce sufficient immunosuppression to prolong the survival of a variety of organ allografts in experimental animals. The degree of prolongation is dose-dependent and is limited by the toxicity that occurs with higher doses. Total lymphoid irradiation is more effective before transplantation than after, but when used after transplantation can be combined with pharmacologic immunosuppression to achieve a positive effect. In some animal models, total lymphoid irradiation induces an environment in which fully allogeneic bone marrow will engraft and induce permanent chimerism in the recipients who are then tolerant to organ allografts from the donor strain. If total lymphoid irradiation is ever to have clinical applicability on a large scale, it would seem that it would have to be under circumstances in which tolerance can be induced. However, in some animal models graft-versus-host disease occurs following bone marrow transplantation, and methods to obviate its occurrence probably will be needed if this approach is to be applied clinically. In recent years, patient and graft survival rates in renal allograft recipients treated with conventional immunosuppression have improved considerably, and thus the impetus to utilize total lymphoid irradiation for its immunosuppressive effect alone is less compelling. The future of total lymphoid irradiation probably lies in devising protocols in which maintenance immunosuppression can be eliminated, or nearly eliminated, altogether. Such protocols are effective in rodents. Whether they can be applied to clinical transplantation remains to be seen

Study of radiation grafted and sulfonated poly(tetrafluoroethylene-co-hexafluoropropylene), FEP, membranes

International Nuclear Information System (INIS)

Mohamed Mahmoud Nasef; Hamdani Saidi; Hussin Mohd Nor

1999-01-01

Radiation grafted and sulfonated FEP membranes were prepared by radiation-induced grafting of styrene onto poly(tetrafluoroethylene-co-hexafluoropropylene) films at room temperature and subsequently sulfonated. The membrane composition was controlled via variation of the grafting conditions such as type of diluent, irradiation dose, dose rate and monomer concentration. The membrane properties such as water uptake, ion exchange capacity and ionic conductivity were found to be strongly dependent upon the degree of grafting. The membranes were shown to have a good combination of physico-chemical properties, which made them promising for development of low cost proton exchange membranes

Study of PVC membrane grafted by Acrylic Acid, Acrylonitrile and Acrylamide using preirradiation method

International Nuclear Information System (INIS)

Kattan, M.; Al-Kasseri, H.

2015-03-01

Grafting of acrylic acid, acrylamide and acrylonitrile onto poly vinyl chloride (PVC) films using gamma radiation has been carried out by both type direct and preirradiation methods. The effect of different parameter such as monomer concentration, inhibitor concentration, reaction temperature, reaction time and irradiation dose on the grafting yield were investigated. It was found that the grafting yield depends on these parameters. The grafting yield was strongly monomer dependent and grafting method: the highest was found for AAc by the preirradiation method. The samples were characterized by tensile strength measurement, swilling and ion uptake. The highest increase in swilling was observed on samples grafted with AAc by the preirradiation method.(author)

The effects of different schedules of total-body irradiation in heterotopic vascularized bone transplantation. An experimental study in the Lewis rat

International Nuclear Information System (INIS)

Gonzalez del Pino, J.; Benito, M.; Randolph, M.A.; Weiland, A.J.

1990-01-01

To evaluate the effects of irradiation on heterotopically placed vascularized knee isografts, a single dose of 10 Gy of total-body irradiation was given to Lewis donor rats. Irradiation was delivered either 2 or 6 days prior to harvesting or subsequent transplantation, and evaluated at 1, 2, and 4 weeks after grafting. Irradiation caused endothelial depopulation of the graft artery, although vascular pedicle patency was maintained throughout the study. Bone graft viability and mineralization were normal. Dramatic changes in the bone marrow were seen that included an increase of its fat content (P less than 0.001), and a concomitant decrease in bone marrow-derived immunocompetent cells. These changes were more prominent in recipients of grafts from day -6 irradiated donor rats. Total-body irradiation did not prejudice the use of vascularized bone grafts, and exhibited an associated immunosuppresant effect over the vascular endothelium and bone marrow. This may be a further rational conditioning procedure to avoid recipient manipulation in vascularized bone allotransplantation

Inactivation of enveloped and non-enveloped viruses in the process of chemical treatment and gamma irradiation of bovine-derived grafting materials.

Science.gov (United States)

Lee, Kwang-Il; Lee, Jung-Soo; Jung, Hong-Hee; Lee, Hwa-Yong; Moon, Seong-Hwan; Kang, Kyoung-Tak; Shim, Young-Bock; Jang, Ju-Woong

2012-01-01

Xenografts, unlike other grafting products, cannot be commercialized unless they conform to stringent safety regulations. Particularly with bovine-derived materials, it is essential to remove viruses and inactivate infectious factors because of the possibility that raw materials are imbrued with infectious viruses. The removal of the characteristics of infectious viruses from the bovine bone grafting materials need to be proved and inactivation process should satisfy the management provision of the Food and Drug Administration (FDA). To date, while most virus inactivation studies were performed in human allograft tissues, there have been almost no studies on bovine bone. To evaluate the efficacy of virus inactivation after treatment of bovine bone with 70% ethanol, 4% sodium hydroxide, and gamma irradiation, we selected a variety of experimental model viruses that are known to be associated with bone pathogenesis, including bovine parvovirus (BPV), bovine herpes virus (BHV), bovine viral diarrhea virus (BVDV), and bovine parainfluenza-3 virus (BPIV-3). The cumulative virus log clearance factor or cumulative virus log reduction factor for the manufacturing process was obtained by calculating the sum of the individual virus log clearance factors or log reduction factors determined for individual process steps with different physicochemical methods. The cumulative log clearance factors achieved by three different virus inactivation processes were as follows: BPV ≥ 17.73, BHV ≥ 20.53, BVDV ≥ 19.00, and BPIV-3 ≥ 16.27. On the other hand, the cumulative log reduction factors achieved were as follows: BPV ≥ 16.95, BHV ≥ 20.22, BVDV ≥ 19.27, and BPIV-3 ≥ 15.58. Treatment with 70% ethanol, 4% sodium hydroxide, or gamma irradiation was found to be very effective in virus inactivation, since all viruses were at undetectable levels during each process. We have no doubt that application of this established process to bovine bone graft manufacture will be

Grafting on nuclear tracks using the active sites that remain after the etching process

International Nuclear Information System (INIS)

Mazzei, R.; Bermudez, G. Garcia; Chappa, V.C.; Grosso, M.F. del; Fernandez, A.

2006-01-01

Poly(propylene) foils were irradiated with Ag ions and then chemically etched to produce samples with structured surfaces. After the etching procedure the active sites that remain on the latent track were used to graft acrylic acid. Nuclear tracks before grafting were visualised using a transmission electron microscope. The grafting yields were determined by weight measurements as a function of ion fluence, etching and grafting time, and were also analysed using Fourier transform infrared spectroscopy. Both measurements suggest that the acrylic acid was grafted on etched tracks using the active sites produced by the swift heavy ion beam

Grafting on nuclear tracks using the active sites that remain after the etching process

Energy Technology Data Exchange (ETDEWEB)

Mazzei, R. [Unidad de Aplicaciones Tecnologicas y Agropecuarias, CNEA, 1429 Buenos Aires (Argentina) and Universidad Tecnologica Nacional, Buenos Aires (Argentina)]. E-mail: mazzei@cae.cnea.gov.ar; Bermudez, G. Garcia [U. A. de Fisica, Tandar, CNEA, 1429 Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, UNSAM, 1653 Buenos Aires (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); Chappa, V.C. [U. A. de Fisica, Tandar, CNEA, 1429 Buenos Aires (Argentina); Grosso, M.F. del [U. A. de Fisica, Tandar, CNEA, 1429 Buenos Aires (Argentina); U. A. de Materiales, CNEA, 1429 Buenos Aires (Argentina); Fernandez, A. [Universidad Tecnologica Nacional, Buenos Aires (Argentina)

2006-09-15

Poly(propylene) foils were irradiated with Ag ions and then chemically etched to produce samples with structured surfaces. After the etching procedure the active sites that remain on the latent track were used to graft acrylic acid. Nuclear tracks before grafting were visualised using a transmission electron microscope. The grafting yields were determined by weight measurements as a function of ion fluence, etching and grafting time, and were also analysed using Fourier transform infrared spectroscopy. Both measurements suggest that the acrylic acid was grafted on etched tracks using the active sites produced by the swift heavy ion beam.

Thermogravimetric studies on electron beam initiated grafting of triallyl cyanurate onto polyethylene

International Nuclear Information System (INIS)

Chaki, T.K.; Bhowmik, A.K.; Mukunda, P.G.; Majali, A.B.; Tikku, V.K.

1993-01-01

Low density polyethylene (LDPE) containing different levels of triallyl cyanurate (TAC) have been prepared in a Brabender Plasticorder at 120 degC. The moulded samples in the form of rectangular compression sheet were irradiated under electron beam accelerator with different irradiation doses. Thermogravimetric and derivative thermogravimetric analyses of the irradiated samples grafted with TAC have been carried out in order to explore the decomposition behaviour and kinetics of decomposition under nitrogen atmosphere. Initial decomposition temperature (Ti), temperature at which 50% weight loss takes place (T50), final decomposition temperature (Tf) and the kinetic parameters evaluated from TGA traces of samples at different radiation doses (constant TAC level) and at different levels of TAC (constant radiation dose) have been reported. The effect of radiation dose and TAC level on the grafting of TAC onto polyethylene have been explained on the basis of degradation characteristics of irradiated samples. Kinetic studies show that the degradation of the irradiated samples follow first order reaction kinetics. Activation energies of degradation have been determined using McCarty and Green's method. Activation energy of the irradiated samples increases with the increasing radiation dose and also with increasing level of TAC. (author). 3 tabs

Development of anionic membranes produced by radiation-grafting for alkaline fuel cell applications

International Nuclear Information System (INIS)

Pereira, Clotilde Coppini

2017-01-01

Anion Exchange Membranes (AEMs) are a promising alternative to the development of more efficient electrolytes for alkaline fuel cells. In general, the AEMs are ionomeric membranes able to conduct hydroxide ions (OH - ) due to the quaternary ammonium groups, which confer high pH equivalent to the AEM. In order to develop alkaline membranes with high chemical and thermal stability, besides satisfactory ionic conductivity for alkaline fuel cells, membranes based on low density polyethylene (LDPE), ultrahigh weight molecular weight polyethylene (UHWHPE), poly(ethylene-co-tetrafluoroethylene) (PETFE) and poly(hexafluoropropylene-co-tetrafluoroethylene) (PFEP) previously irradiated by using 60 Co gamma and electron beam sources, have been synthesized by styrene-grafting, and functionalized with trimethylamine to introduced quaternary ammonium groups. The resulting membranes were characterized by electron paramagnetic resonance (EPR), Raman spectroscopy, thermogravimetry (TG) and electrochemical impedance spectroscopy (EIS). The determination of the grafting degree and water uptake were conducted by gravimetry and ion exchange capacity, by titration. The membranes synthesized with PELD and PEUHMW polymers pre-irradiated at 70 kGy and stored at low temperature (-70 deg C), up to 10 months, showed ionic conductivity results, in hydroxide form (OH - ), of 29 mS.cm -1 and 14 mS.cm -1 at 65 deg C, respectively. The PFEP polymers irradiated by the simultaneous process showed insufficient grating levels for the membrane synthesis, requiring more studies to improve the irradiation and grafting process. The styrene-grafted PETFE membranes, pre-irradiated at 70 kGy and stored at low temperature (-70 deg C), up to 10 months, showed ionic conductivity results, in hydroxide form (OH - ), of 90 mS.cm -1 to 165 mS.cm -1 , in the temperature range 30 to 60 deg C. Such results have demonstrated that LDPE, UHMWPE and PETFE based AEMs are promising electrolytes for alkaline fuel cell

Effect of storage conditions on graft of polypropylene non-woven fabric induced by electron beam

Energy Technology Data Exchange (ETDEWEB)

Lee, Jin Young; Jeun, Joon Pyo; Kang, Phil Hyun [Radiation Research Dvision for Industry and Environment, Korea Atomic Energy Research Institute, Jeongeup(Korea, Republic of)

2015-05-15

In this study, we fabricated effect of storage conditions on graft of polypropylene (PP) non-woven fabric induced by electron beam. The electron beam irradiations on PP non-woven fabric were carried out over a range of irradiation doses from 25 to 100 kGy to make free radicals on fabric surface. The radical measurement was established by electron spin resonance (ESR) for confirming the changes of the alkyl radical and peroxy radical according to effect of storage time, storage temperature and atmosphere. It was observed that the free radicals were increased with irradiation dose and decreased with storage time due to the continuous oxidation. However, the radical extinction was significantly delayed due to reduced mobility of radicals at extremely low temperature. The degree of graft based on the analysis of ESR was investigated. The conditions of graft reaction were set at a temperature: 60 degrees Celcius, reaction time: 6 hours and styrene monomer concentration: 20 wt%.

PP films grafted with N-isopropylacrylamide and N-(3-aminopropyl) methacrylamide by gamma radiation: synthesis and characterization

Energy Technology Data Exchange (ETDEWEB)

Contreras-Garcia, Angel [Departamento de Quimica de Radiaciones y Radioquimica, Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, Mexico DF 04510 (Mexico); Alvarez-Lorenzo, Carmen; Concheiro, Angel [Departamento de Farmacia y Tecnologia Farmaceutica, Universidad de Santiago de Compostela, 15782-Santiago de Compostela (Spain); Bucio, Emilio, E-mail: ebucio@nucleares.unam.m [Departamento de Quimica de Radiaciones y Radioquimica, Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, Mexico DF 04510 (Mexico)

2010-05-15

Simultaneous grafting of N-isopropylacrylamide (NIPAAm) and N-(3-aminopropyl) methacrylamide hydrochloride (APMA) on polypropylene (PP) was investigated for obtaining interfaces that are stimuli-responsive under physiological conditions. A pre-irradiation method was optimized tuning the gamma-irradiation dose, reaction time, temperature, and monomers concentrations. FT-IR ATR and XPS analysis of the grafted copolymers evidenced a greater content in NIPAAm than in APMA; the APMA/NIPAAm ratio increasing with the concentration of APMA in the reaction medium and when the grafting was carried out in 1 M NaNO{sub 3}. The grafted films were characterized regarding their thermal properties (DSC and TGA) swelling behavior and contact angle. Immersion of the pre-irradiated films in 1 M NIPAAm/0.5 M APMA aqueous solution rendered PP-g-(1NIPAAm-r-0.5APMA) which exhibited rapid and reversible transitions showing a LCST around the physiological temperature. By contrast, a greater content in APMA enhanced the hydrophilicity and prevented the shrinking of PP-g-(1NIPAAm-r-1APMA).

PP films grafted with N-isopropylacrylamide and N-(3-aminopropyl) methacrylamide by γ radiation: synthesis and characterization

International Nuclear Information System (INIS)

Contreras-Garcia, Angel; Alvarez-Lorenzo, Carmen; Concheiro, Angel; Bucio, Emilio

2010-01-01

Simultaneous grafting of N-isopropylacrylamide (NIPAAm) and N-(3-aminopropyl) methacrylamide hydrochloride (APMA) on polypropylene (PP) was investigated for obtaining interfaces that are stimuli-responsive under physiological conditions. A pre-irradiation method was optimized tuning the γ-irradiation dose, reaction time, temperature, and monomers concentrations. FT-IR ATR and XPS analysis of the grafted copolymers evidenced a greater content in NIPAAm than in APMA; the APMA/NIPAAm ratio increasing with the concentration of APMA in the reaction medium and when the grafting was carried out in 1 M NaNO 3 . The grafted films were characterized regarding their thermal properties (DSC and TGA) swelling behavior and contact angle. Immersion of the pre-irradiated films in 1 M NIPAAm/0.5 M APMA aqueous solution rendered PP-g-(1NIPAAm-r-0.5APMA) which exhibited rapid and reversible transitions showing a LCST around the physiological temperature. By contrast, a greater content in APMA enhanced the hydrophilicity and prevented the shrinking of PP-g-(1NIPAAm-r-1APMA).

Preparation of the copolymer of acrylic acid and acrylamide grafted onto polyethylene and its complexation with samarium ion

International Nuclear Information System (INIS)

Kido, Junji; Akiba, Hideto; Nishide, Hiroyuki; Tsuchida, Eishun; Omichi, Hideki; Okamoto, Jiro.

1986-01-01

Acrylic acid (AA) and acrylamide (AAm) were graft-copolymerized onto polyethylene (PE) powder by the pre-irradiation method. Complex formation constants of Sm ion with the PE powder grafted with both AA and AAm (PE-g-(AA-co-AAm)) were larger than those with the PE powder grafted with AA (PE-g-AA). Sm ion was efficiently separated from the solution containing both Sm ion and a transition metal ion such as Cu ion. Even after the γ-ray irradiation on PE-g-(AA-co-AAm) and PE-g-AA, the adsorption did not decrease. (author)

Temperature-sensitive porous membrane production through radiation co-grafting of NIPAAm on/in PVDF porous membrane

International Nuclear Information System (INIS)

Liu Qi; Zhu Zhiyong; Yang Xiaomin; Chen Xiliang; Song Yufeng

2007-01-01

N-isopropylacrylamide (NIPAAm) monomer was grafted on and in poly(vinylidene fluoride) (PVDF) micro-pore membrane by γ-irradiation. The influence of irradiation and reaction conditions on the grafting yield was investigated in detail. The chemical structure of NIPAAm-grafted PVDF (NIPAAm-g-PVDF) membrane was characterized by Fourier transform infrared spectra and X-ray photoelectron spectra measurements. The morphology of the sample surface as well as the cross-section before and after grafting was characterized by scanning electron microscope. The temperature sensitive properties of the membrane were monitored by measuring the conductance as well as the water flux through the sample thickness. The results show that the membrane exhibits clearly temperature-sensitive permeability to water as expected, i.e. the permeability of water changes dramatically as the temperature goes over the lower critical solution temperature of NIPAAm

Highly hydrophilic ultra-high molecular weight polyethylene powder and film prepared by radiation grafting of acrylic acid

Energy Technology Data Exchange (ETDEWEB)

Wang, Honglong [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xu, Lu; Li, Rong [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Pang, Lijuan [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Hu, Jiangtao; Wang, Mouhua [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Wu, Guozhong, E-mail: wuguozhong@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)

2016-09-30

Highlights: • Hydrophilic UHMWPE powder and film were obtained by γ-ray pre-irradiation grafting of AA. • A low concentration of AA solution was used for surface modification of UHMWPE. • A small grafting yield of AA sufficiently improved hydrophilicity of UHMWPE powder and film. - Abstract: The surface properties of ultra-high molecular weight polyethylene (UHMWPE) are very important for its use in engineering or composites. In this work, hydrophilic UHMWPE powder and film were prepared by γ-ray pre-irradiation grafting of acrylic acid (AA) and further neutralization with sodium hydroxide solution. Variations in the chemical structure, grafting yield and hydrophilicity were investigated and compared. FT-IR and XPS analysis results showed that AA was successfully grafted onto UHMWPE powder and film; the powder was more suitable for the grafting reaction in 1 wt% AA solution than the film. Given a dose of 300 kGy, the grafting yield of AA was ∼5.7% for the powder but ∼0.8% for the film under identical conditions. Radiation grafting of a small amount of AA significantly improved the hydrophilicity of UHMWPE. The water contact angle of the UHMWPE-g-PAA powder with a grafting yield of AA at ∼5.7% decreased from 110.2° to 68.2°. Moreover, the grafting powder (UHMWPE-g-PAA) exhibited good dispersion ability in water.

Radiation grafting of pH and thermosensitive N-isopropylacrylamide and acrylic acid onto PTFE films by two-steps process

International Nuclear Information System (INIS)

Bucio, E.; Burillo, G.

2007-01-01

Polytetrafluoroethylene (PTFE) was grafted (g) with acrylic acid (AAc) by γ-ray pre-irradiation method to get PTFE-g-AAc films, then N-isopropylacrylamide (NIPAAm) was grafted onto PTFE-g-AAc films with γ-ray to get (PTFE-g-AAc)-g-NIPAAm. PTFE films were irradiated in air at a dose rate of 3.0 kGy h -1 and different radiation dose. The irradiated films were placed in glass ampoules, which contained aqueous solutions with different monomer concentration (AAc), and then they were heated at different temperatures and reaction time. NIPAAm onto PTFE-g-AAc was carried out with the same procedure with monomer concentration of 1 mol L -1 . The thermosensitivity of the samples was defined and calculated as the ratio of the grafted samples swelling at 28 and 35 o C, and pH sensitivity defined as the ratio of the grafted samples swelling at pH 2 and 8

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

Immunocytoadherence and sublethal irradiation

International Nuclear Information System (INIS)

Beaumariage, M.L.; Hiesche, K.; Revesz, L.; Haot, J.

1975-01-01

In sublethally irradiated CBA mice, the relative and absolute numbers of spontaneous rosette forming cells against sheep erythrocytes are markedly decreased in bone marrow. The decrease of the absolute number of spontaneous RFC is also important in the spleen in spite of an increase of the RFC relative number above the normal values between the 8th and 12th day after irradiation. The graft of normal bone marrow cells immediately after irradiation or the shielding of a medullary area during irradiation promotes the recovery of the immunocytoadherence capacity of the bone marrow cells but not of the spleen cells [fr

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

Cryopreserved irradiated tracheal homograft reconstruction for subglottic-tracheal stenosis

International Nuclear Information System (INIS)

Somyos Kunachak; Yongyudh Vajaradul; Boonchu Kulapaditharom

1999-01-01

Subglottic-tracheal stenosis is a common clinical entity. Handling on severe case is often problematic. Various tracheal replacement techniques have been used with varying degree of success and dispute. In this study we worked on cryopreserved irradiated tracheal homograft, of which its use in human has not been reported. The tracheas were harvested from donor cadavers within 24 hours of death in a sterile condition. After 1-2 weeks of preservation at -70 degree C, the grafts were irradiated at 25 kGy, then stored at -70 degree C until used. Four patients, 2 males and 2 females (aged 2-40 years, mean 16 years) with severe subglottic-tracheal stenosis underwent segmental tracheal graft reconstruction using this graft. Immunosuppressant was not given in any patient. The follow up period ranged from 11-1 5 months. Three patients were successfully decapulated, 1 patient developed local infection and dislodgement of intraluminal stent with subsequent restenosis. Postoperative tracheal lumen appeared near normal with histologic evidence of normal respiratory epithelium at the grafted site. In conclusion, cryopreserved irradiated tracheal homograft is a valuable alternative for tracheal transplant or reconstruction, without the need of immunosuppression

Preparation of the proton exchange membranes for fuel cell under pre-irradiation induced grafting method

International Nuclear Information System (INIS)

Li Jingye; Muto, F.; Matsuura, A.; Kakiji, T.; Miura, T.; Oshima, A.; Washio, M.; Katsumura, Y.

2006-01-01

Proton exchange membranes (PEMs) were prepared via pre-irradiation induced grafting of styrene or styrene/divinylbenzene (S/DVB) into the crosslinked polytetrafluoroethylene (RX-PTFE) films with thickness around 10 m and then sulfonated by chlorosulfonic acid. The membrane electrode assembles (MEAs) based on these PEMs with ion exchange capacity (IEC) values around 2meq/g were prepared by hot-press with Nafion dispersion coated on the surfaces of the membranes and electrodes. And the MEA based on the Nafion 112 membrane was also prepared under same procedure as a comparison. The performances of the MEAs in single fuel cell were tested under different working temperatures and humidification conditions. The performance of the synthesized PEMs showed better results than that of Nafion 112 membrane under low humidification at 80 degree C. The electrochemical impedance spectra (EIS) were taken with the direct current density of 0.5A/cm 2 and the resulted curves in Nyqvist representation obeyed the half circle pattern. (authors)

Interaction of blood with radiation-grafted materials

International Nuclear Information System (INIS)

Ikada, Y.; Suzuki, M.; Taniguchi, M.; Iwata, H.; Taki, W.; Miyake, H.; Yonekawa, Y.; Handa, H.

1981-01-01

Extensive works on blood compatibility of polymeric materials have revealed that it is strongly governed by their surface structure and properties. Among them are roughness, hydrophobic-hydrophilic balance, ionic species, and water content in the surface layer. In the present work, low and high density polyethylenes as well as heat-treated poly(vinyl) alcohol are grafted with acrylamide (and acrylic acid for comparison) by a pre-irradiation technique to convert the rigid hydrophobic surface into a soft hydrogel with high water contents. The surface modification of materials with grafted polyacrylamide chains will be confirmed from the contact angle measurement which is one of the best methods for assessing the hydrophilicity of surfaces. Blood compatibility of the resulting surfaces will be evaluated from in vivo experiments by anastomosing the surface-grafted tubes of small diameter with the carotid artery of rat. (author)

Studies of blood irradiator application

International Nuclear Information System (INIS)

Li Wenhong; Lu Yangqiao

2004-01-01

Transfusion is an important means for medical treatment, but it has many syndromes such as transfusion-associated graft-versus-host disease, it's occurrence rate of 5% and above 90% death-rate. Now many experts think the only proven method is using blood irradiator to prevent this disease. It can make lymphocyte of blood product inactive, so that it can not attack human body. Therefore, using irradiation blood is a trend, and blood irradiator may play an important role in medical field. This article summarized study of blood irradiator application, including the meaning of blood irradiation, selection of the dose for blood irradiation and so on

Potential advantages of treatment of transplanted saphenous vein aorto-coronary artery bypass grafts with beta irradiation to prevent graft occlusion.

Science.gov (United States)

Smith, R G

1997-01-01

Intimal proliferation or Neointimal hyperplasia (NIH) is a vascular lesion that often arises in arteries after balloon angioplasty or other vessel wall injuries. FIH is a vascular lesion that develops in autologous saphenous vein grafts (SVG) after transplantation into the aorto-coronary circulation or the peripheral vascular circulation. FIH shares elements of smooth muscle migration, proliferation and fibrous tissue deposition in common with nibrointimal proliferation (NIH). Either NIH of a coronary artery or FIH of a SVG obstruct the vascular lumen and result in myocardial dysfunction. Local radiotherapy has been used for several decades to reduce the post-operative recurrence of the fibrovascular proliferations of pterygia and keloids. Similarly, in animal and human experiments, endovascular radiotherapy has been shown to reduce arterial smooth muscle proliferation. Consideration of the similarities of vascular smooth muscle cell proliferation in NIH and FIH leads one to suggest that endovascular beta irradiation can reduce FIH as well as it reduces NIH. The goal of such treatment is to achieve a clinically significant decrease in the morbidity and mortality resulting from SVG occlusions. The potential for large reduction of the consequences of SVG occlusion, the very large number of patients at risk, and the simplicity of the proposed intervention encourages prompt scientific evaluation of this technique.

Reconstruction of irradiated bone segmental defects with a biomaterial associating MBCP+(R), microstructured collagen membrane and total bone marrow grafting: an experimental study in rabbits.

Science.gov (United States)

Jégoux, Franck; Goyenvalle, Eric; Cognet, Ronan; Malard, Olivier; Moreau, Francoise; Daculsi, Guy; Aguado, Eric

2009-12-15

The bone tissue engineering models used today are still a long way from any oncologic application as immediate postimplantation irradiation would decrease their osteoinductive potential. The aim of this study was to reconstruct a segmental critical size defect in a weight-bearing bone irradiated after implantation. Six white New Zealand rabbits were immediately implanted with a biomaterial associating resorbable collagen membrane EZ(R) filled and micro-macroporous biphasic calcium phosphate granules (MBCP+(R)). After a daily schedule of radiation delivery, and within 4 weeks, a total autologous bone marrow (BM) graft was injected percutaneously into the center of the implant. All the animals were sacrificed at 16 weeks. Successful osseous colonization was found to have bridged the entire length of the defects. Identical distribution of bone ingrowth and residual ceramics at the different levels of the implant suggests that the BM graft plays an osteoinductive role in the center of the defect. Periosteum-like formation was observed at the periphery, with the collagen membrane most likely playing a role. This model succeeded in bridging a large segmental defect in weight-bearing bone with immediate postimplantation fractionated radiation delivery. This has significant implications for the bone tissue engineering approach to patients with cancer-related bone defects.

Efficacy of prophylactic irradiation in altering renal allograft survival

International Nuclear Information System (INIS)

Faber, R.; Johnson, H.K.; Braren, H.V.; Richie, R.E.

1974-01-01

Renal allograft rejection is a complex phenomenon involving both cell-mediated and humoral antibody responses. Most transplant programs have used a combination of therapeutic modalites to combat the immune system in an attempt to prolong both allograft and patient survival. Corticosteroids (methylprednisolone (Solu-Medrol) and prednisone and azathioprine (Imuran) are widely accepted as immunosuppressive drugs; however, both are non-specific and have the disadvantage of compromising the recipients' defense mechanisms. Nevertheless, these drugs have proved to be essential to the success of renal transplantation and they are routinely used while the efficacy of other modalities continues to be evaluated. We could find no reports of a prospective study to evaluate the efficacy of prophylactic irradiation in the complex therapeutic situation of renal transplantation with the only variable being the administration of local graft irradiation. The purpose of this study was to evaluate prophylactic graft irradiation for its effectiveness in preventing graft rejection in conjunction with Imuran and corticosteroids

Optimization of process parameter for graft copolymerization of glycidyl methacrylate onto delignified banana fibers

International Nuclear Information System (INIS)

Selambakkannu, S.; Nor Azillah Fatimah Othman; Siti Fatahiyah Mohamad

2016-01-01

This paper focused on pre-treated banana fibers as a trunk polymer for optimization of radiation-induced graft copolymerization process parameters. Pre-treated banana fiber was grafted with glycidyl methacrylate (GMA) via electron beam irradiation. Optimization of grafting parameters in term of grafting yield was analyzed at numerous radiation dose, monomer concentration and reaction time. Grafting yield had been calculated gravimetrically against all the process parameters. The grafting yield at 40 kGy had increases from 14 % to 22.5 % at 1 h and 24 h of reaction time respectively. Grafting yield at 1 % of GMA was about 58 % and it increases to 187 % at 3 % GMA. The grafting of GMA onto pre-treated banana fibers confirmed with the characterization using FTIR, SEM and TGA. Grafting of GMA onto pre-treated fibers was successfully carried out and it was confirmed by the results obtained via the characterization. (author)

The Radiation Induced Graft Copolymerization of Methacrylic Acid to Nylon; Copolymerisation par greffe de l'acide methacrylique sur le nylon, provoquee par irradiation; Obluchenie vyzyvaet graft-kopolimerizats yu metakrilovoj kisloty v nejlone; Injerto del acido metacrilico en el nylon por copolimerizacion radioinducida

Energy Technology Data Exchange (ETDEWEB)

Roberts, R; Thomas, J K

1960-07-15

The grafting of methacrylic acid to nylon by the preirradiation technique has been studied. The rate of grafting is appreciably larger than that of homopolymerization. No simple relation exists between reaction rate and total dose. The temperature dependence of the rate of grafting to the fibre, preirradiated in air, indicates that initiation of grafting is likely to take place by decomposition of peroxide groups formed on irradiation. Electrical resistance measurements on the irradiated fibre indicate that this has been reduced by a factor of 10. (author) [French] On a etudie le greffage de l'acide methacrylique sur du nylon par la technique de preirradiation. La vitesse du greffage est sensiblement plus grande que celle de l'homopolymerisation. Il n'existe pas de rapport simple entre la vitesse de reaction et la dose totale. Le fait que la vitesse du greffage sur la fibre, pre-irradiee a l'air, depend de la temperature, indique que l'amorcage de la greffe est susceptible d'etre provoque par la decomposition des groupements de peroxyde formes lors de l'irradiation. Les mesures de resistance electrique effectuees sur la fibre irradiee indiquent que cette resistance a ete reduite au dixieme de la valeur originale. (author) [Spanish] Al estudiar la copolimerizacio n de injerto del acido metacrilico en el nylon por el procedimiento de preirradiacion, los autores comprobaron que la velocidad de injerto es sensiblemente mas elevada que la de homopolimerizacion. No existe una relacion sencilla entre la velocidad de reaccion y la dosis total. La influencia de la temperatura sobre la velocidad de injerto en la fibra previamente irradiada en aire indica que el proceso se inicia por descomposicion de los grupos peroxido formados durante la irradiacion. Las mediciones efectuadas demuestran que la resistencia electrica de la fibra irradiada solo alcanza la decima parte de la correspondiente a la fibra no tratada. (author) [Russian] Bylo provedeno izuchenie prosachivaniya

Radiation induced graft copolymerization of methyl methacrylate onto chrome-tanned pig skins

International Nuclear Information System (INIS)

Pietrucha, K.; Pekala, W.; Kroh, J.

1981-01-01

Graft copolymerization of methyl methacrylate (MMA) onto chrome-tanned pig skins was carried out by irradiation with 60 Co γ-rays. The grafted polymethyl methacrylate (PMMA) chains were isolated by acid hydrolysis of the collagen backbone in order to characterize the graft copolymers. Proof of grafting was obtained through the detection of amino acid endgroups in the isolated grafts by reaction with ninhydrin. The grafting yield of MMA in aqueous emulsion was found to be higher than that for pure MMA and MMA in acetone. The degree of grafting increases with increasing monomer concentration in emulsion and reaches maximum at radiation dose ca 15 kGy. The yield of grafting is very high. The present paper reports the physical properties of chrome-tanned pig skins after graft polymerization with MMA in emulsion. Modified leathers are more resistant against water absorption and abrasion in comparison with unmodified ones. They have more uniform structure over the whole surface, greater thickness and stiffness. The mechanism of some of the processes occurring during radiation grafting of MMA in water emulsion on tanned leathers has been also suggested and discussed. (author)

Radiation induced graft copolymerization of methyl methacrylate onto chrome-tanned pig skins

Energy Technology Data Exchange (ETDEWEB)

Pietrucha, K.; Pekala, W.; Kroh, J. (Lodz Univ. (Poland))

1981-01-01

Graft copolymerization of methyl methacrylate (MMA) onto chrome-tanned pig skins was carried out by irradiation with /sup 60/Co ..gamma..-rays. The grafted polymethyl methacrylate (PMMA) chains were isolated by acid hydrolysis of the collagen backbone in order to characterize the graft copolymers. Proof of grafting was obtained through the detection of amino acid endgroups in the isolated grafts by reaction with ninhydrin. The grafting yield of MMA in aqueous emulsion was found to be higher than that for pure MMA and MMA in acetone. The degree of grafting increases with increasing monomer concentration in emulsion and reaches maximum at radiation dose ca 15 kGy. The yield of grafting is very high. The present paper reports the physical properties of chrome-tanned pig skins after graft polymerization with MMA in emulsion. Modified leathers are more resistant against water absorption and abrasion in comparison with unmodified ones. They have more uniform structure over the whole surface, greater thickness and stiffness. The mechanism of some of the processes occurring during radiation grafting of MMA in water emulsion on tanned leathers has been also suggested and discussed.

Metal Adsorbent Prepared from Poly(Methyl Acrylate)-Grafted Cassava Starch via Gamma Irradiation

Energy Technology Data Exchange (ETDEWEB)

Suwanmala, P; Hemvichian, K; Srinuttrakul, W [Nuclear Research and Development Group, Thailand Institute of Nuclear Technology, Bangkok (Thailand)

2012-09-15

Metal adsorbent containing hydroxamic acid groups was successfully synthesized by radiation-induced graft copolymerization of methyl acrylate (MA) onto cassava starch. The optimum conditions for grafting were studied in terms of % degree of grafting (Dg). Conversion of the ester groups present in poly(methyl acrylate)-grafted-cassava starch copolymer into hydroxamic acid was carried out by treatment with hydroxylamine (HA) in the presence of alkaline solution. The maximum percentage conversion of the ester groups of the grafted copolymer, %Dg = 191 (7.63 mmol/g of MA), into the hydroxamic groups was 70% (5.35 mmol/g of MA) at the optimum conditions: in a mixture solution of 20% HA (w/v) and methanol solution (methanol:H{sub 2}O = 5:1) 300 mL, pH 13, reaction time 2 h, and 20 g of grafted copolymer. The adsorbent was characterized by FTIR, TGA, and DSC. The presence of electron donating groups in adsorbent containing hydroxamic acid groups gives the ability to form polycomplexes with metal ions. The ability of the adsorbent to adsorb various metals was investigated in order to evaluate the possibility of its use in metal adsorption. The adsorbent exhibited a remarkable % adsorption for Cd{sup 2+}, Al{sup 3+}, UO{sub 2} {sup 2+}, V{sup 5+} and Pb{sup 2+} at pH 3, 4, 5, 4, and 3, respectively. The adsorbent of 191%Dg had total adsorption capacities of 2.6, 1.46, 1.36, 1.15, and 1.6 mmol/g adsorbent for Cd{sup 2+}, Al{sup 3+}, UO{sub 2} {sup 2+}, V{sup 5+} and Pb{sup 2+}, respectively, in the batch mode adsorption. (author)

Diversity of gut microflora is required for the generation of B cell with regulatory properties in a skin graft model.

Science.gov (United States)

Alhabbab, R; Blair, P; Elgueta, R; Stolarczyk, E; Marks, E; Becker, P D; Ratnasothy, K; Smyth, L; Safinia, N; Sharif-Paghaleh, E; O'Connell, S; Noelle, R J; Lord, G M; Howard, J K; Spencer, J; Lechler, R I; Lombardi, G

2015-06-25

B cells have been reported to promote graft rejection through alloantibody production. However, there is growing evidence that B cells can contribute to the maintenance of tolerance. Here, we used a mouse model of MHC-class I mismatched skin transplantation to investigate the contribution of B cells to graft survival. We demonstrate that adoptive transfer of B cells prolongs skin graft survival but only when the B cells were isolated from mice housed in low sterility "conventional" (CV) facilities and not from mice housed in pathogen free facilities (SPF). However, prolongation of skin graft survival was lost when B cells were isolated from IL-10 deficient mice housed in CV facilities. The suppressive function of B cells isolated from mice housed in CV facilities correlated with an anti-inflammatory environment and with the presence of a different gut microflora compared to mice maintained in SPF facilities. Treatment of mice in the CV facility with antibiotics abrogated the regulatory capacity of B cells. Finally, we identified transitional B cells isolated from CV facilities as possessing the regulatory function. These findings demonstrate that B cells, and in particular transitional B cells, can promote prolongation of graft survival, a function dependent on licensing by gut microflora.

Diversity of gut microflora is required for the generation of B cell with regulatory properties in a skin graft model

Science.gov (United States)

Alhabbab, R.; Blair, P.; Elgueta, R.; Stolarczyk, E.; Marks, E.; Becker, P. D.; Ratnasothy, K.; Smyth, L.; Safinia, N.; Sharif-Paghaleh, E.; O’Connell, S.; Noelle, R. J.; Lord, G. M.; Howard, J. K.; Spencer, J.; Lechler, R. I.; Lombardi, G.

2015-01-01

B cells have been reported to promote graft rejection through alloantibody production. However, there is growing evidence that B cells can contribute to the maintenance of tolerance. Here, we used a mouse model of MHC-class I mismatched skin transplantation to investigate the contribution of B cells to graft survival. We demonstrate that adoptive transfer of B cells prolongs skin graft survival but only when the B cells were isolated from mice housed in low sterility “conventional” (CV) facilities and not from mice housed in pathogen free facilities (SPF). However, prolongation of skin graft survival was lost when B cells were isolated from IL-10 deficient mice housed in CV facilities. The suppressive function of B cells isolated from mice housed in CV facilities correlated with an anti-inflammatory environment and with the presence of a different gut microflora compared to mice maintained in SPF facilities. Treatment of mice in the CV facility with antibiotics abrogated the regulatory capacity of B cells. Finally, we identified transitional B cells isolated from CV facilities as possessing the regulatory function. These findings demonstrate that B cells, and in particular transitional B cells, can promote prolongation of graft survival, a function dependent on licensing by gut microflora. PMID:26109230

Development and Application of Chlorinated, Fluorinated and Technological Polymer Films Modified by Grafting Process Using Electron Beam and Gamma Radiation

Energy Technology Data Exchange (ETDEWEB)

Manzoli, J E [Nuclear Energy National Commission, Nuclear and Energetic Research Institute, Sao Paulo (Brazil); Universidade Sao Judas Tadeu, Sao Paulo (Brazil); Geraldo, A B.C.; Moura, E; Somesari, E S.R.; Silveira, C G; Oikawa, H; Moreira, N S; Forbicini, C [Nuclear Energy National Commission, Nuclear and Energetic Research Institute, Sao Paulo (Brazil); Tenorio, E [FATEC, Tatui (Brazil); Augusto, C G [IFSP, Sao Paulo (Brazil); Universidade Sao Judas Tadeu, Sao Paulo (Brazil); Panzarini, L C.G.A. [FEI, Sao Bernardo do Campo (Brazil)

2012-09-15

The ionizing irradiation (electron beam and gamma irradiation) induced grafting to fluorinated and chlorinated polymeric films were studied. Styrene grafting onto fluorinated and perfluorinated polymers and their ulterior sulfonation constitute a process to produce ionomers for many applications. The modification of polyvinylchloride with dimethylaminethylmethacrylate-heparin grafting attempt for the fact that grafting can be applied in packaging industry as an alternative for decreasing of plasticizer or another chemical species migration, in many cases nocivus contaminant for human health, and, in the specific study of this project, to obtain a less thrombogenic polymer surface to be used in medical applications. The results indicate mutual styrene grafting performed by industrial EB accelerator can be a fast alternative to produce ionomers that can compete in market. The numerical method to simulate diffusion process evolved is simple and fast and applied to fit experimental results. (author)

Solvent influence during radiation induced grafting of styrene in PVDF

International Nuclear Information System (INIS)

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

2013-01-01

Radiation-induced grafting was studied to produce styrene grafted poly(vinylidene fluoride) (PVDF) membranes. PVDF films with 0.125 mm thickness were irradiated at doses between 5 and 20 kGy in the presence of styrene/N,N-dimethylformamide (DMF), styrene/acetone or styrene/toluene solutions (1:1, v/v) at dose rate of 5 kGy h -1 by simultaneous method, using gamma rays from a Co-60, under nitrogen atmosphere and at room temperature. The films were characterized before and after modification by grafting yield (GY %), infrared spectroscopy (FT-IR), scanning electron microscopy (SEM and EDS), differential scanning calorimetry (DSC) and thermogravimetry (TG/DTG). GY results shows that grafting increases with dose and toluene hinders the grafting, leading to a small GY comparing to DMF and acetone. It was possible to confirm the grafting of styrene by FT-IR due to the new characteristics peaks and by the TG and DSC due to changes in thermal behavior of the grafted material. SEM and EDS show surface and cross-section distribution of the grafting, which takes place on the surface and heterogeneously with toluene as solvent and homogeneously and penetrating into the inner layers of the matrix using DMF and acetone as solvent. (author)

Solvent influence during radiation induced grafting of styrene in PVDF

Energy Technology Data Exchange (ETDEWEB)

Ferreira, Henrique P.; Parra, Duclerc F.; Lugao, Ademar B., E-mail: hp.ferreira@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2013-07-01

Radiation-induced grafting was studied to produce styrene grafted poly(vinylidene fluoride) (PVDF) membranes. PVDF films with 0.125 mm thickness were irradiated at doses between 5 and 20 kGy in the presence of styrene/N,N-dimethylformamide (DMF), styrene/acetone or styrene/toluene solutions (1:1, v/v) at dose rate of 5 kGy h{sup -1} by simultaneous method, using gamma rays from a Co-60, under nitrogen atmosphere and at room temperature. The films were characterized before and after modification by grafting yield (GY %), infrared spectroscopy (FT-IR), scanning electron microscopy (SEM and EDS), differential scanning calorimetry (DSC) and thermogravimetry (TG/DTG). GY results shows that grafting increases with dose and toluene hinders the grafting, leading to a small GY comparing to DMF and acetone. It was possible to confirm the grafting of styrene by FT-IR due to the new characteristics peaks and by the TG and DSC due to changes in thermal behavior of the grafted material. SEM and EDS show surface and cross-section distribution of the grafting, which takes place on the surface and heterogeneously with toluene as solvent and homogeneously and penetrating into the inner layers of the matrix using DMF and acetone as solvent. (author)

Homologous tracheal transplantation with grafts previously exposed to high doses of gamma radiation in dogs without immunosuppressive agents

International Nuclear Information System (INIS)

Yokomise, Hiroyasu; Inui, Kenji; Kure, Toshio; Wada, Hiromi; Itomi, Shigeki

1993-01-01

The study was designed to determine whether previous high doses irradiation of gamma radiation would contribute to tracheal transplantation with no use of immunosuppressive agents. Twenty mongrel dogs were used as experimental animals. Five rings of thoracic tracheas, which were extracted from recipients, were exposed to 20000, 50000, or 100000 cGy in each 5 dogs. Five other non-irradiated dogs served as controls. Irradiated tracheal grafts were transplanted and covered with pedicled omentum. After transplantation, no immunosuppressive agents were given to dogs. All dogs in the control group died of tracheal stenosis due to graft-host rejection within one month. All but one long-term survivor died of tracheal stenosis, as well, in both the 20000 cGy and 50000 cGy groups. In the 100000 cGy group, grafts became viable in 4 dogs, and three of these survived one year or more. In conclusion, previous irradiation with high doses of 100000 cGy allowed homologous tracheal transplantation even when no immunosuppressive agents are given. (N.K.)

Comparative study of the monomer grafting: ethylene, acetylene, 1,3-butadiene and estyrene in the matrix of recycled polytetrafluoroethylene (PTFE)

International Nuclear Information System (INIS)

Ikari, Carolina T.; Rosner, Gerhardyne O.; Oliveira, Ana C.F.; Ferreto, Helio F.R.; Lima, Luiz F.C.P.; Lugao, Ademar B.; Moreira, Otavio M.

2009-01-01

In this study it is used the recycled polytetrafluoroethylene (PTFE), that with the gamma radiation under inert atmosphere or in presence of air, it is obtained free radicals and a posterior the monomer grafting (ethylene, acetylene, styrene or 1.3 butadiene), obtaining the copolymer polytetrafluoroethylene-g-monomer. It is studied the obtention of the polymer by two methods: by direct way, via grafting, where the polymer is irradiated in presence of monomer, and via grafting when the polymer is irradiated in absence of monomer and under inert or air. The characterization of the copolymer was performed by the techniques of infrared region absorption spectroscopy with Fourier transformation (FTIR), thermogravimetric (TGA) and derivative thermogravimetry (DTG), and percentage of mass grafting (DOG)

Radiation Induced Grafting of Acrylate onto Waste Rubber: The Effect of Monomer Type

Directory of Open Access Journals (Sweden)

Shirajuddin Siti Salwa M.

2017-01-01

Full Text Available The effect of three different acrylate group monomers, namely n-butyl acrylate, methacrylic acid and tripropylene glycol diacrylate of radiation induced grafting onto waste rubber was studied. The electron beam accelerator operated at voltage of 2MeV was used to irradiate the waste rubber at 10 kGy and 100 kGy absorbed radiation dose, respectively. The formation of grafting was observed from the increase in the grafting yield and confirmed by Transformed Infra-Red Spectroscopy results. According to the result obtained, only tripropylene glycol diacrylate was selected to graft onto waste rubber. The carbonyl bond from acrylate groups was seen at 1726 cm-1 band which confirmed the presence of TPGDA in the polymer matrix. This indicates the successful preparation of the TPGDA-grafted waste rubber via radiation induced grafting techniques.

Radiation-induced grafting polymerization of MMA onto polybutadiene rubber latex

International Nuclear Information System (INIS)

Peng Jing; Wang Maolin; Qiao Jinliang; Wei Genshuan

2005-01-01

The grafting of methyl methacrylate (MMA) onto polybutadiene rubber latex by the direct radiation method was carried out. The effects of monomer concentration, absorbed dose and dose rate of gamma rays on the grafting yield were investigated. The graft copolymers were characterized by transmission electron microscopy (TEM), FTIR spectroscopy, and differential scanning calorimetry. TEM photographs revealed that the core-shell structures of latex particles are formed at low MMA content, and with the increasing of MMA content, the semi-IPN-like structure with core-shell could be developed due to the high gel fraction of polybutadiene (PBD) seed particles. In addition, infrared analysis confirmed that MMA could be grafted onto PBD molecular chains effectively under appropriate irradiation conditions. The interfacial adhesion between PBD rubber (core) and PMMA (shell) phases could be enhanced with the increase of MMA concentration

Radiation graft copolymerization of n-butyl acrylate on natural rubber latex

International Nuclear Information System (INIS)

Sundardi, F.; Kadariah, S.

1986-01-01

A method of radiation graft copolymerization of n-butyl acrylate (NBA) on natural rubber (NR) latex has been studied. The rate of conversion increases with the increase of NBA in latex. An irradiation dose of about 12 kGy is needed to obtain 90% conversion with 40 phr of NBA in latex. Tensile strength, tear strength, and elongation at break of grafted NR are found to decrease with increasing degree of grafting. The physical strength of a vulcanizate prepared from a mixture of NR and ply-NBA was found to be better than that of NBA-NR graft copolymer vulcanizate. The graft copolymerization reaction takes place in the outer layer of NR particles, and because the secondary bonds between poly-NBA molecules may be weaker than those between NR molecules, the existence of a poly-NBA layer in NR particles will decrease its physical strength

Effect of gamma-irradiation on mouse pancreatic islet-allograft survival

International Nuclear Information System (INIS)

Kanai, T.; Porter, J.; Gotoh, M.; Monaco, A.P.; Maki, T.

1989-01-01

Elimination or inactivation of lymphoid tissue in the pancreatic islet preparation achieves prolongation of islet-allograft survival. In this study we examined the effect of gamma-irradiation on mouse islet-allograft survival. In a B6AF1 isograft model, irradiation up to 2400 rad did not induce deterioration of islet function over 200 days, but greater doses caused cessation of graft function between 83 and 186 days. When DBA/2 crude islets were transplanted into B6AF1 recipients, all nonirradiated allografts were acutely rejected. Marked prolongation of allograft survival was achieved by islet irradiation with doses between 800 and 12,000 rad. With higher doses, significant numbers of allografts survived beyond the controls, but many lost function between 78 and 180 days, with none surviving greater than 200 days. Irradiation with 16,000 rad caused acute radiation damage. Because most secondary islet allografts in recipient mice that lost primary islet-graft function between 84 and 195 days survived greater than 100 days, late functional loss was probably due to the radiation injury. Combined use of recipient treatment with cyclosporin A and graft irradiation (2400 rad) achieved prolongation of DBA/2 islets in B6AF1 mice

Osteogenic Matrix Cell Sheets Facilitate Osteogenesis in Irradiated Rat Bone

Directory of Open Access Journals (Sweden)

Yoshinobu Uchihara

2015-01-01

Full Text Available Reconstruction of large bone defects after resection of malignant musculoskeletal tumors is a significant challenge in orthopedic surgery. Extracorporeal autogenous irradiated bone grafting is a treatment option for bone reconstruction. However, nonunion often occurs because the osteogenic capacity is lost by irradiation. In the present study, we established an autogenous irradiated bone graft model in the rat femur to assess whether osteogenic matrix cell sheets improve osteogenesis of the irradiated bone. Osteogenic matrix cell sheets were prepared from bone marrow-derived stromal cells and co-transplanted with irradiated bone. X-ray images at 4 weeks after transplantation showed bridging callus formation around the irradiated bone. Micro-computed tomography images at 12 weeks postoperatively showed abundant callus formation in the whole circumference of the irradiated bone. Histology showed bone union between the irradiated bone and host femur. Mechanical testing showed that the failure force at the irradiated bone site was significantly higher than in the control group. Our study indicates that osteogenic matrix cell sheet transplantation might be a powerful method to facilitate osteogenesis in irradiated bones, which may become a treatment option for reconstruction of bone defects after resection of malignant musculoskeletal tumors.

Surface grafting of styrene on polypropylene fibers by argon plasma and its adsorption-regeneration of BTX

Science.gov (United States)

Xu, J. J.; Guo, M. L.; Chen, Q. G.; Lian, Z. Y.; Wei, W. J.; Luo, Z. W.; Xie, G.; Chen, H. N.; Dong, K.

2017-08-01

Active macromolecular free radicals were generated on polypropylene (PP) fibers surfaces by argon (Ar) plasma irradiation, then, PP surface modified fibers (PP-g-St fibers) were prepared by in-situ grafting reaction of styrene monomers (St). Effects of reaction parameters on grafting percentage were studied and adsorption capacities of PP-g-St fibers for benzene, toluene and xylene (BTX) were evaluated. Afterwards, regeneration adsorption efficiencies after maximum adsorption were explored. The results indicated that the optimum input power, irradiation time and grafting reaction time are 90 W, 3 min and 3 h respectively and the grafting percentage of St reached 5.7 %. The adsorption capacities of PP-g-St fibers towards toluene and xylene emulsions and solutions in water increased by 336.89 % and 344.57 % respectively, compared to pristine PP fibers. In addition, regeneration adsorption efficiencies of modified fibers remained > 90 % after six cycles of regeneration-adsorption experiments, which showed excellent regeneration ability.

Radiation graft polymerization of 4- vinylpyridine on polyvinylchloride-films. [Gamma radiation

Energy Technology Data Exchange (ETDEWEB)

Kudryavtsev, V.N.; Shapiro, A.; Endrikhovska-Bonamur, A.M.

1984-01-01

Radiation graft liquid phase polymerization of 4-vinylpyridine on PVC-films by the method of direct radiation is investigated. The samples are irradiated by Co/sup 60/ ..gamma..-source at 20 deg C and the dose rate of 39 Gy/s for 4-vinylpyridine solutions in methonol, as well as at-78 deg C and dose rate of 1.3 kGy/s for monomer solutions in hexane. Modified polyvinylchloride films with grafted poly-4-vinylpyridine chains are prepared. Being introduced in grafted polyvinylpyridine chains of ion-exchange groups, materials are characterized by good swelling in water and are good to prepare anion-exchange membranes.

Chemical structure of chromium(III) crosslinked collagen-poly(methyl methacrylate) copolymers in radiation grafting

International Nuclear Information System (INIS)

Pietrucha, K.

1991-01-01

Upon γ-irradiation of aqueous emulsions of methyl methacrylate embedded into chrome tanned skin, the formation of graft copolymers is observed. The number-average molecular weight of the grafted poly(methyl methacrylate) side chains was in the range of 430000 (for a dose of 10 kGy) and practically independent of grafting degree. However, the number of branches per graft copolymer molecule increases from 0.3 to 0.8 when the degree of grafting increases from 32% to 88%. Similarly, the radiation yield, i.e. the number of branches formed per 100 eV of energy absorbed in the substrate polymer increases from 0.75 to 1.94. The value and meaning of molecular weight of graft copolymer is discussed along with the mechanism of polymer chain termination. (author) 14 refs.; 3 figs.; 4 tabs

Allograft tissue irradiation and failure rate after anterior cruciate ligament reconstruction: A systematic review.

Science.gov (United States)

Dashe, Jesse; Parisien, Robert L; Cusano, Antonio; Curry, Emily J; Bedi, Asheesh; Li, Xinning

2016-06-18

To evaluate whether anterior cruciate ligament (ACL) allograft irradiation is effective for sterility without compromising graft integrity and increasing failure rate. A literature search was conducted using PubMed, Cochrane, and Google. The following search terms were used: "Gamma irradiation AND anterior cruciate ligament AND allograft" with a return of 30 items. Filters used included: English language, years 1990-2015. There were 6 hits that were not reviewed, as there were only abstracts available. Another 5 hits were discarded, as they did not pertain to the topic of interest. There were 9 more articles that were excluded: Three studies were performed on animals and 6 studies were meta-analyses. Therefore, a total of 10 articles were applicable to review. There is a delicate dosing crossover where gamma irradiation is both effective for sterility without catastrophically compromising the structural integrity of the graft. Of note, low dose irradiation is considered less than 2.0 Mrad, moderate dose is between 2.1-2.4 Mrad, and high dose is greater than or equal to 2.5 Mrad. Based upon the results of the literature search, the optimal threshold for sterilization was found to be sterilization at less than 2.2 Mrad of gamma irradiation with the important caveat of being performed at low temperatures. The graft selection process also must include thorough donor screening and testing as well as harvesting the tissue in a sterile fashion. Utilization of higher dose (≥ 2.5 Mrad) of irradiation causes greater allograft tissue laxity that results in greater graft failure rate clinically in patients after ACL reconstruction. Allograft ACL graft gamma irradiated with less than 2.2 Mrad appears to be a reasonable alternative to autograft for patients above 25 years of age.

Radiation-induced grafting of sweet sorghum stalk for copper(II) removal from aqueous solution

International Nuclear Information System (INIS)

Dong, Jing; Hu, Jun; Wang, Jianlong

2013-01-01

Highlights: • Radiation-induced grafting was used to modify the stalk. • Cellulose, hemicellulose and lignin participated in grafting reaction. • Both the structure and composition of stalk had influence on grafting. • The sorption capacity of the grafted stalk increased about five times. -- Abstract: The influence of main components (cellulose, hemicellulose and lignin) of the sweet sorghum stalk on radiation-induced grafting reaction and adsorption of copper from aqueous solution was investigated. Sweet sorghum stalk was grafted with acrylic acid induced by γ-irradiation. The results showed that the grafted stalk contained 1.6 mmol/g carboxyl groups, and its maximal adsorption capacity was 13.32 mg/g. The cellulose, hemicellulose and lignin of the raw materials were confirmed to involve in grafting reaction through comparing the grafting yield and the structure of the grafted materials. Both the structure and the composition of the sweet sorghum stalk had influence on the grafting reaction and adsorption capacity. The adsorption capacity of the grafted sweet sorghum stalk increased about five times, and the adsorption isotherm of the grafted materials conformed to the Langmuir model. The main mechanism for copper adsorption involved in ion exchange

Radiation grafting of methacrylate onto carbon nanofiber surface

International Nuclear Information System (INIS)

Evora, M.C.; Klosterman, D.; Lafdi, K.; Li, L.

2011-01-01

Radiation can be used to modify and improve the properties of materials. Electron beam irradiation has potential application in modifying the structure of carbon fibers in order to produce useful defects in the graphite structure and create reactive sites. In this study, vapor grown carbon nano fibers (VGCF) were irradiated with a high energy (3 MeV) electron beam in air to dose of 1000 kGy to create active sites and added to methyl methacrylate (MMA) dissolved in water/methanol (50% V). The irradiated samples were analyzed by X-Ray Photoelectron Spectroscopy (XPS) and Raman spectroscopy to assess the impact on surface and bulk properties. Oxygen was readily incorporated enhancing the dispersion of VGCF. Raman spectroscopy analyses indicated that the sample irradiated and preirradiated grafted sample with MMA had the intensity ratio increased. (author)

Grafting of glycidyl methacrylate/styrene onto polyvinyldine fluoride membranes for proton exchange fuel cell

International Nuclear Information System (INIS)

Abdel-Hady, E.E.; El-Toony, M.M.; Abdel-Hamed, M.O.

2013-01-01

Simultaneous gamma irradiation was used effectively for grafting facilitation of glycidyl methacrylate (GMA) and styrene (Sty) onto polyvinylidine fluoride (PVDF). Grafting percent was 122 when monomers ratio are 30% Sty and 70% GMA at 20 KGy gamma irradiation dose. Characterization of the membrane was performed using FT-IR, ion exchange capacity (IEC), water uptake. Mechanical behavior such as tensile strength was studied while morphological structure of the membrane was carried out by scan electron microscope (SEM). The membrane with degree of grafting 122% showed higher IEC (1.2 m mol/cm) than those of Nafion membrane with corresponding proton conductivity of 5.7 × 10 −2 S/cm similar to it. Operating the fuel cell unit showed higher voltage of the prepared membranes than that of Nafion 211. The prepared membranes stability for 300 h work approved their applicability from the cost benefit point of view

Effect of solubility parameter of monomers on electron beam induced graft-polymerization onto polyethylene films

International Nuclear Information System (INIS)

Mori, Koji; Koshiishi, Kenji; Masuhara, Ken-ichi

1991-01-01

Electron beam induced graft-polymerization by the mutual irradiation technique of monomers with different solubility parameters δ onto low density polyethylene films (LDPE) and high density polyethylene films (HDPE) were investigated at high dose rates (25 Mrad per second). Graft-polymerization mechanisms were discussed on the basis of grafting rates, surface tensions, atomic ratios of surface by XPS, and SEM images of the grafted films. Grafting rates decreased with increasing δ of monomers, and grafting rates onto LDPE were larger than those onto HDPE. Graft chain contents on surface, which were evaluated in terms of surface tensions and atomic ratios of the surface, increased with increasing δ of monomers, and graft chain contents on surface of HDPE were higher than those of LDPE. It is assumed that mutual solubility of PE and monomers, i.e., infiltration of monomers into PE during graft-polymerization influence grafting rates and graft sites in films. In case of high mutual solubility, grafting rates were large and graft sites spread from the surface into bulk. On the other hand, in case of low mutual solubility, grafting rates were small and graft sites localized on the surface of films. (author)

Surface modification of silica nanoparticles by UV-induced graft polymerization of methyl methacrylate.

Science.gov (United States)

Kim, Sooyeon; Kim, Eunhye; Kim, Sungsoo; Kim, Woosik

2005-12-01

In this study we modified the surface of silica nanoparticles with methyl methacrylate by UV-induced graft polymerization. It is a surface-initiated polymerization reaction induced by ultraviolet irradiation. The resulting organic-inorganic nanocomposites were near-monodisperse and fabricated without homopolymerization of the monomer. Substantial increase in mean particle size was observed by SEM image analysis after UV-induced grafting of methyl methacrylate onto pure silica particles. FT-Raman spectroscopy and X-ray photoelectron spectroscopy studies of these materials revealed the successful grafting of methyl methacrylate onto the silica surface. The formation of a covalent bond between the grafted PMMA chains and silica surface was indicated by FT-Raman spectra. Thermogravimetric analysis of the PMMA-grafted silica particles indicated the polymer contents in good agreement with SEM photographs.

Dose uniformity estimations in the blood irradiator

International Nuclear Information System (INIS)

George, J.R.

2002-01-01

Use of irradiated blood in transfusions is recognized as the most effective way of preventing Graft Versus Host Disease (GVHD). This paper shows the study carried out in the dose rate variation for various source arrangements for optimising the source-sample chamber geometry, during the development of the Blood Irradiator, Bl-2000

Allogeneic bone marrow grafts in genotyped swine

International Nuclear Information System (INIS)

Vaiman, M.

1974-01-01

The proof of a major histocompatibility complex (MHC) called SL-A enabled to promote bone marrow allografts. A study of the response to that kind of graft in irradiated pig states a number of interesting points. Bone marrow allografting complies with the rule of tissular compatibility with the major histocompatibility complex. The taking of SL-A incompatible bone marrow allografts could not be achieved under the experimental conditions. In spite of the high doses of radiation, 950 to 1050 rads, higher than 1.5 LD 100%, recipients were capable of rejecting their grafts, regularly. SL-A identify ensured 100%, initial achievement. However, animals developed regular fatal disease within a fairly short time. This development could by no means, be ascribed to the sole sequealae of radiation sickness since autografted animals at equal or even higher doses, showed none of the symptome. Assumption of a chronic graft-vs-host reactions, induced by the minor histocompatible systems, was put foreward, but should be confirmed histopathologically [fr

Fully portable blood irradiator

International Nuclear Information System (INIS)

Hungate, F.P.; Riemath, W.F.; Bunnell, L.R.

1980-01-01

A fully portable blood irradiator was developed using the beta emitter thulium-170 as the radiation source and vitreous carbon as the body of the irradiator, matrix for isotope encapsulation, and blood interface material. These units were placed in exteriorized arteriovenous shunts in goats, sheep, and dogs and the effects on circulating lymphocytes and on skin allograft retention times measured. The present work extends these studies by establishing baseline data for skin graft rejection times in untreated animals

Modification of polyethersulfone films by grafting hydrophilic monomers with 60Co γ-rays

International Nuclear Information System (INIS)

Hou Zhengchi; Deng Bo; Li Jing

2006-01-01

Polyethersulfone (PES), with its high strength, high temperature resistance, corrosion- resistance, oxidation resistance and applicability under wide pH range, is used extensively as ultrafiltration and nanofiltration membrane. However, PES membranes foul easily in such an application because of hydrophobic nature of PES raw materials. Improving the hydrophilicity of PES by grafting hydrophilic monomers onto it is of potential to solve the problem. At present, common approaches to improve hydrophilicity of PES membranes are UV grafting modification, plasma modification, and chemical modification, whereas grafting and modifying PES films by 60 Co γ-rays has rarely been reported. Studies have been carried out in our laboratory to graft hydrophilic monomers onto PES membranes directly or PES powders via simultaneous radiation grafting with the rays. Acrylic acid, methyl acrylic acid or acrylamide was used to study effects of the monomer concentration, irradiation dose and dose rate, solvent, inhibitor and pH of the grafting solution on the degree of grafting. The results showed that hydrophilicity of all the PES membranes could be improved, with the extent of improvement being dependent on the grafting conditions. (authors)

Radiation-grafting of acrylamide onto silicone rubber films for diclofenac delivery

International Nuclear Information System (INIS)

Magaña, Hector; Palomino, Kenia; Cornejo-Bravo, Jose M.; Alvarez- Lorenzo, Carmen; Concheiro, Angel; Bucio, Emilio

2015-01-01

This work focuses on the pre-irradiation grafting of acrylamide (AAm) onto silicone rubber films (SR) and evaluates the effect of gamma-ray radiation conditions on the grafting yield, which in turn may influence the performance of the grafted materials as components of drug-eluting devices. Pristine and modified SR were characterized using FTIR-ATR, DSC, TGA, swelling, and water contact angle analysis in order to elucidate the effects of AAm grafting onto SR. Grafted films with content in AAm ranging from 0.81% to 22.20% showed excellent cytocompatibility against fibroblasts, and capability to uptake the anti-inflammatory drug diclofenac. Amount of drug loaded directly correlated with the grafting degree of the films. Drug release studies were performed at pH 7.4 and 37 °C (physiological conditions). Most grafted films released the drug in a sustained way for at least three hours. - Highlights: • SR–g-AAm depends on dose, monomer concentration, and reaction time and temperature. • Diclofenac sodium salt is loaded and released in a sustained way from SR–g-AAm films. • SR–g-AAm films are cytocompatible and have potential as components of drug–device

Swelling, ion uptake and biodegradation studies of PE film modified through radiation induced graft copolymerization

Energy Technology Data Exchange (ETDEWEB)

Kaur, Inderjeet, E-mail: ij_kaur@hotmail.com [Department Chemistry, HPU Shimla 171005 (India); Gupta, Nitika; Kumari, Vandna [Department Chemistry, HPU Shimla 171005 (India)

2011-09-15

An attempt to develop biodegradable polyethylene film grafting of mixture of hydrophilic monomers methacrylic acid (MAAc) and acrylamide (AAm) onto PE film has been carried out by preirradiation method using benzoyl peroxide as the radical initiator. Since ether linkages are susceptible to easy cleavage during degradation process, PE film was irradiated before the grafting reactions by {gamma}-rays to introduce peroxidic linkages (PE-OO-PE) that offer sites for grafting. The effect of irradiation dose, monomer concentration, initiator concentration, temperature, time and amount of water on the grafting percent was determined. Maximum percentage of grafting of binary mixture (MAAc+AAm), (1792%) was obtained at a total concentration of binary monomer mixture=204.6x10{sup -2} mol/L ([MAAc]=176.5x10{sup -2} mol/L, [AAm]=28.1x10{sup -2} mol/L), [BPO]=8.3x10{sup -2} mol/L at 100 deg. C in 70 min. The grafted PE film was characterized by the Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopic (SEM) methods. Some selective properties of grafted films such as swelling studies, ion uptake and biodegradation studies have been investigated. The grafted films show good swelling in water, ion uptake studies shows promising results for desalination of brackish water and the soil burial test shows that PE film grafted with binary monomer mixture degrades up to 47% within 50 days. - Highlights: > Binary mixture of methacrylic acid (MAAc) and acrylamide (AAm) onto PE film by preirradiation method was carried out. > Graft copolymers of MAAc+AAm and PE film were characterized by FTIR, TGA and SEM studies and was found to be thermally stable. > Grafting of MAAc+AAm improved swelling behavior giving maximum swelling (485.71%) in water as against PE with 0% swelling. > The grafted PE-g-poly (MAAc-co-AAm) behaves as an excellent material for ion separation. > Biodegradation studies by soil burial test showed 47.19% of

Evidence for successful acceptance of irradiated free gingival allografts in dogs

International Nuclear Information System (INIS)

Rubenstein, H.S.; Ruben, M.P.; Levy, C.; Peiser, S.

1975-01-01

Free graft samples were excised and frozen to -55 0 C. Subsequently the grafts were exposed to 2.5 x 10 6 rads of 60 Co γ-radiation. The irradiated allogeneic grafts were later reconstituted and surgically transferred to four recipient subjects. Three autogenous nonirradiated grafts were also placed as controls. The animals were killed so as to furnish healing data at 0, 3, 7, 10, and 40 days postoperatively. Fourteen allografts were evaluated. They were judged to be nonantigenic, immunologically incompetent and nonviable. However, retention of an essentially unaltered connective tissue corium may have been instrumental in supporting subsequent epithelial regeneration from adjacent host tissue, while being passively incorporated into a very dynamic receptor zone. The graft thus served as a scaffolding for connective tissue deposition and attachment. It appears that the experimental regime obviated the immunologic interference usually encountered in allografting procedures. Thus, high intensity irradiation of the graft tissue may have rendered the tissue to be immunologically tolerable. Further studies are required to ascertain the duration of the host's immunologic unresponsiveness to the alien tissue, as well as ultimate structural and biologic fate of the transplanted tissues. Experiments are now in progress which have been designed to test the extent of immunologic sensitization induced by the grafted tissue

Effect of solubility parameter of solvents on electron beam induced graft-polymerization onto polyethylene films

International Nuclear Information System (INIS)

Mori, Koji; Koshiishi, Kenji; Masuhara, Ken-ichi

1992-01-01

Electron beam induced graft-polymerization by the mutual irradiation technique of methyl methacrylate (MMA) and methacrylic acid (MAAc) blended with solvents, which have different solubility parameters δ, onto high density polyethylene films (PE) were investigated at high dose rates (25 Mrad per second). Graft-polymerization mechanisms were discussed on the basis of grafting rates, surface tensions, atomic rations on the surface by XPS, and SEM images of the grafted films. Grafting rates decreased with increasing δ of solvents, and grafting rates for MMA were larger than those for MAAc. Graft chain contents on the surface, which were evaluated in terms of surface tensions and atomic ratios on the surface, increased with increasing δ of solvents, and graft chain contents on the surface of MAAc grafted PE were higher than those of MMA grafted PE. It is assumed that mutual solubility of PE and solvents (monomer solutions), i.e., infiltration of monomer solutions into PE during graft-polymerization, influenced grafting rates and graft sites in films. In case of high mutual solubility, grafting rates were large and graft sites spread from the surface into bulk. On the other hand, in case of low mutual solubility, grafting rates were small and graft sites localized on the surface of films. (author)

Radiation-induced graft polymerization of amphiphilic monomers with different polymerization characteristics onto hydrophobic polysilane

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Hidenori; Iwasaki, Isao; Kunai, Yuichiro [Research Reactor Institute, Kyoto University, Asashironishi 2-1010, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Sato, Nobuhiro, E-mail: sato-n@rri.kyoto-u.ac.j [Research Reactor Institute, Kyoto University, Asashironishi 2-1010, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Matsuyama, Tomochika [Research Reactor Institute, Kyoto University, Asashironishi 2-1010, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan)

2011-08-15

The structures of poly(methyl-n-propylsilane) (PMPrS) amphiphilically modified through {gamma}-ray-induced graft polymerization were investigated with {sup 1}H NMR measurement. By the use of methyl methacrylate (MMA) or diethyl fumarate (DEF) as monomers for the graft polymerization, grafting yield rose with increasing total absorption dose and monomer concentrations, but decreased with increasing dose rate. This result means that grafting yield of modified PMPrS can be controlled by changing irradiation conditions. However, the number of PMMA or PDEF graft chains per PMPrS chain was estimated to be less than 1.0 by analysis of {sup 1}H NMR spectra, and this value was lower than that we had expected. To improve graft density, maleic anhydride (MAH), which is known as a non-homopolymerizable monomer in radical polymerization, was used as a monomer for grafting. As a result, high density grafting (one MAH unit for 4.2 silicon atoms) was attained. It demonstrates that the structure of {gamma}-ray-modified polysilane strongly depends on the polymerization characteristics of grafted monomers.

Improved biotribological properties of PEEK by photo-induced graft polymerization of acrylic acid

Energy Technology Data Exchange (ETDEWEB)

Zhao, Xiaoduo; Xiong, Dangsheng, E-mail: xiongds@163.com; Wang, Kun; Wang, Nan

2017-06-01

The keys of biomaterials application in artificial joints are good hydrophilicity and wear resistance. One kind of the potential bio-implant materials is polyetheretherketone (PEEK), which has some excellent properties such as non-toxic and good biocompatibility. However, its bioinert surface and inherent chemical inertness hinder its application. In this study, we reported an efficient method for improving the surface wettability and wear resistance for PEEK, a layer of acrylic acid (AA) polymer brushes on PEEK surface was prepared by UV-initiated graft polymerization. The effects of different grafting parameters (UV-irradiation time/AA monomer solution concentration) on surface characteristics were clearly investigated, and the AA-g-PEEK specimens were examined by ATR-FTIR, static water contact angle measurements and friction tests. Our results reveal that AA can be successfully grafted onto the PEEK surface after UV irradiation, the water wettability and tribological properties of AA-g-PEEK are much better than untreated PEEK because that AA is a hydrophilic monomer, the AA layer on PEEK surface can improve its bearing capacity and reduce abrasion. This detailed understanding of the grafting parameters allows us to accurately control the experimental products, and this method of surface modification broadens the use of PEEK in orthopedic implants. - Highlights: • Acrylic acid was successful grafted onto PEEK substrate by UV-initiated graft polymerization. • AA-g-PEEK owned better hydrophilicity than untreated PEEK. • Wear resistance of AA-g-PEEK were significantly improved due to AA brushes could bear high contact stress.

On the influence of X-ray surface radiation of the donor or recipient site on the revascularisation of autologous free full thickness skin grafts

International Nuclear Information System (INIS)

Lange, R.

1972-01-01

Experimental X-ray injuries of the skin were created on guineapigs with contact therapy conditions with a total dose of 14,000 or 12,000R. Measurements of the skin temperature and heat release of the skin show that regardless of whether the donor or recipient site was injured, a reproduction of the plethora and a reduction of the blood circulation of antologous, free full thickness skin grafts was brought about compared to control grafts if the operation was performed 2 - 3 weeks after ending irradiation. Extensively corresponding results were obtained if the operation was performed 5 months after terminating irradiation; however, an increased blood circulation was detected on the 7th post-operative day with the pre-injury of the graft bed. Corresponding measurements on 10 human full thickness skin grafts with radiation-injured graft bed and 15 comparison grafts also showed a negative influence of the revascularisation by the X-ray injury of the graft bed. (orig./LH) [de

In vitro release studies of vitamin B12 from poly N-vinyl pyrrolidone /starch hydrogels grafted with acrylic acid synthesized by gamma radiation

International Nuclear Information System (INIS)

Eid, M.

2008-01-01

Co-polymeric hydrogels containing N-vinyl pyrrolidone and starch grafted with acrylic acid were synthesized by gamma radiation. Their gel contents, grafting process and swelling were evaluated. The gels were also characterized by thermal gravimetric analysis. The gel content found to be increase with increasing the irradiation dose up to 50 kGy then decrease. The grafting percent increase by increasing the percentage of acrylic acid in the grafted hydrogels. The thermal stability and the rate of the thermal decomposition showed to be changed according to the different composition of the hydrogels. It also showed a decrease in the maximum rate of the thermal decomposition by the increasing of the irradiation dose from 20 to 30 kGy and increases by increasing the irradiation dose from 30 to 70 kGy. The hydrogels loaded with vitamin B 12 as drug model, demonstrated a decrease release in acidic medium than the neutral one

Radiation synthesis of chitosan beads grafted with acrylic acid for metal ions sorption

International Nuclear Information System (INIS)

Benamer, S.; Mahlous, M.; Tahtat, D.; Nacer-Khodja, A.; Arabi, M.; Lounici, H.; Mameri, N.

2011-01-01

Radiation-induced grafting of acrylic acid onto chitosan beads was performed in solution at a dose rate of 20.6 Gy/min of cobalt-60 gamma rays. The effect of absorbed dose on grafting yield was investigated. The characterization of the grafted material was performed by FTIR spectroscopy and the swelling measurements at different pHs. The grafting yield increased with the increase in dose, it reached 80% at 40 kGy irradiation dose. The removal of Pb and Cd ions from aqueous solutions was investigated with both ungrafted and grafted chitosan beads. The sorption behavior of the sorbents was examined through pH, kinetics and equilibrium measurements. Grafted chitosan beads presented higher sorption capacity for both metal ions than unmodified chitosan beads. - Highlights: → Pb and Cd ions are removed from aqueous solution by adsorption on chitosan beads. → Crosslinking process improves chemical stability of chitosan beads. → Radiation grafting of acrylic acid onto chitosan improves its metal adsorption capacity. → Increase in grafting degree enhances the adsorption capacity of the material. → Gamma radiation is a powerful tool for an accurate control of the grafting yield.

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

Science.gov (United States)

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.

Progresses in irradiating SBS for road asphalt applications

International Nuclear Information System (INIS)

Li Linfan; Xie Leidong; Fu Haiying; Li Yintao; Yu Min; Sheng Kanglong; Yao Side

2006-01-01

Technical developments at SINAP to improve properties of SBS, a styrene-butadiene- styrene copolymer, for road asphalt applications are reviewed. In an attempt to better solve problems related to undesirable compatibility of SBS to asphalt components, we proposed a new method to modify the SBS molecular chains with ionizing radiations through radiation graft copolymerization and radiation crosslinking. Grafting a monomer with polar functional groups onto SBS molecules improves compatibility of SBS to polar components of asphalt, hence enhanced storage stability of the polymer modified asphalt (PMA), while crosslinks of SBS molecular chains endues increased physical properties to the PMA. Mechanisms of the radiation effects were studied with a series of SBS samples irradiated by 60 Co γ-rays or electron beams. The PMA and macadam-blended PMA samples showed higher performance than the control, i.e. SBS-modified asphalt by conventional approaches. The results can be summarized as follows. 1. The grafted SBS enhances thermostability of saturates and aromatics, the two asphalt components that exhibit the biggest SBS-swelling effect. The resins of asphalt, however, can hardly be absorbed by SBS, and the SBS is in a phase-separation status with the resins. Therefore, it is crucial to strengthen reactions between SBS and the resins to obtain stable and high quality PMA. 2. SBS molecular chains can be crosslinked with irradiation of a few tens of kGy. The crosslinking effect was evidenced by increased molecular weight of SBS and wider distribution of the molecular weight in GPC measurement of the irradiated SBS samples, and by decreased activation energy of viscosity in rheological measurement, in which the storage modulus G' increased and the loss modulus G' declined with increasing doses, indicating a larger elastic component and smaller viscous component in the irradiated SBS. Correspondingly, temperature sensitivity of the irradiated SBS reduced. Blended with SBS

Autologous bone marrow transplantation following chemotherapy and irradiation in dogs with spontaneous lymphomas

International Nuclear Information System (INIS)

Bowles, C.A.; Bull, M.; McCormick, K.; Kadin, M.; Lucas, D.

1980-01-01

Thirty dogs with spontaneous lymphomas were administered two to six cycles of chemotherapy and were randomized into 3 groups to receive 800 rads of total body irradiation and autologous bone marrow transplantation. Of 10 dogs irradiated after chemotherapy-induced remission and infused with remission marrow (group 1), 8 (80%) had successful grafts and experienced remissions lasting 62 to 1024 days. Of 9 dogs irradiated during remission and infused with remission marrow mixed with autologous tumor cells (group 2), 6 (66%) had remission lasting 15 to 45 days. Eleven dogs with progressive tumor growth (relapse) following chemotherapy were irradiated and infused with remission marrow (group 3). Tumor remission lasting 39 to 350 days was observed in 5 dogs (45%) in this group, and 6 dogs died in less than 30 days. Dogs in groups 1 to 3 had median survival times of 216, 60, and 45 days, respectively. The prolonged survival times for dogs in group 1 compared to dogs in groups 2 and 3 suggest that protocols involving irradiation and autologous marrow grafting in this model would be most effective when these protocols are applied to animals having a minimum tumor burden at the time of irradiation and when the grafting is done with tumor-free autologous marrow

G2 checkpoint abrogator abates the antagonistic interaction between antimicrotubule drugs and radiation therapy

International Nuclear Information System (INIS)

Sui Meihua; Zhang Hongfang; Di Xiaoyun; Chang Jinjia; Shen Youqing; Fan Weimin

2012-01-01

Background and purpose: We previously demonstrated that radiation may arrest tumor cells at G2 phase, which in turn prevents the cytotoxicity of antimicrotubule drugs and results in antagonistic interaction between these two modalities. Herein we tested whether G2 abrogators would attenuate the above antagonistic interaction and improve the therapeutic efficacy of combination therapy between radiation and antimicrotubule drugs. Materials and methods: Breast cancer BCap37 and epidermoid carcinoma KB cell lines were administered with radiation, UCN-01 (a model drug of G2 abrogator), paclitaxel or vincristine, alone or in combinations. The antitumor activities of single and combined treatments were analyzed by a series of cytotoxic, apoptotic, cell cycle, morphological and biochemical assays. Results: UCN-01 significantly enhanced the cytotoxicity of radiation, antimitotic drugs, and their combined treatments in vitro. Further investigations demonstrated that UCN-01 attenuated radiation-induced G2 arrest, and subsequently repressed the inhibitory effect of radiation on drug-induced mitotic arrest and apoptosis. Conclusions: This is the first report demonstrating that G2 checkpoint abrogation represses the inhibitory effect of radiation on antimicrotubule drugs, which may be implicated in cancer combination therapy. Considering that G2 abrogators are under extensive evaluation for cancer treatment, our findings provide valuable information for this class of promising compounds.

Prolonged heart xenograft survival using combined total lymphoid irradiation and cyclosporine

International Nuclear Information System (INIS)

Knechtle, S.J.; Halperin, E.C.; Saad, T.; Bollinger, R.R.

1986-01-01

Total lymphoid irradiation and cyclosporine have profound immunosuppressive properties and permit successful heart allotransplantation. Cyclosporine used alone has not permitted consistently successful transplantation between species in all cases. Total lymphoid irradiation has not been applied to xenotransplantation. The efficacy of total lymphoid irradiation alone and in combination with cyclosporine was examined using an animal model of heart xenotransplantation. Heterotopic heart transplants were performed using inbred Syrian hamsters as donors and Lewis rats as recipients. Total lymphoid irradiation was administered preoperatively over 3 weeks for a total dose of 15 gray. Cyclosporine was started on the day of surgery and was given as a daily intramuscular injection of 2.5, 5, or 10 mg/kg/day until rejection was complete. Neither total lymphoid irradiation nor cyclosporine alone markedly prolonged graft survival. However, combined total lymphoid irradiation and cyclosporine, 5 or 10 mg/kg/day, dramatically prolonged graft survival to greater than 100 days in most recipients. There were no treatment-related deaths. In conclusion, combined total lymphoid irradiation and cyclosporine permit successful long-term survival of heart xenotransplants in this hamster-to-rat model

Improved biotribological properties of PEEK by photo-induced graft polymerization of acrylic acid.

Science.gov (United States)

Zhao, Xiaoduo; Xiong, Dangsheng; Wang, Kun; Wang, Nan

2017-06-01

The keys of biomaterials application in artificial joints are good hydrophilicity and wear resistance. One kind of the potential bio-implant materials is polyetheretherketone (PEEK), which has some excellent properties such as non-toxic and good biocompatibility. However, its bioinert surface and inherent chemical inertness hinder its application. In this study, we reported an efficient method for improving the surface wettability and wear resistance for PEEK, a layer of acrylic acid (AA) polymer brushes on PEEK surface was prepared by UV-initiated graft polymerization. The effects of different grafting parameters (UV-irradiation time/AA monomer solution concentration) on surface characteristics were clearly investigated, and the AA-g-PEEK specimens were examined by ATR-FTIR, static water contact angle measurements and friction tests. Our results reveal that AA can be successfully grafted onto the PEEK surface after UV irradiation, the water wettability and tribological properties of AA-g-PEEK are much better than untreated PEEK because that AA is a hydrophilic monomer, the AA layer on PEEK surface can improve its bearing capacity and reduce abrasion. This detailed understanding of the grafting parameters allows us to accurately control the experimental products, and this method of surface modification broadens the use of PEEK in orthopedic implants. Copyright © 2017 Elsevier B.V. All rights reserved.

Radiation-grafting of 2-hydroxyethylmethacrylate and oligo (ethylene glycol) methyl ether methacrylate onto polypropylene films by one step method

Energy Technology Data Exchange (ETDEWEB)

Ramirez-Jimenez, Alejandro [Departamento de Quimica de Radiaciones y Radioquimica, Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, Mexico DF 04510 (Mexico); Alvarez-Lorenzo, Carmen; Concheiro, Angel [Departamento de Farmacia y Tecnologia Farmaceutica, Universidad de Santiago de Compostela, 15782-Santiago de Compostela (Spain); Bucio, Emilio, E-mail: ebucio@nucleares.unam.mx [Departamento de Quimica de Radiaciones y Radioquimica, Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, Mexico DF 04510 (Mexico)

2012-01-15

Polypropylene films were modified with 2-hydroxyethylmethacrylate (HEMA) and oligo (ethylene glycol) methyl ether methacrylate (OEGMA) using the pre-irradiation method with gamma-rays (one step method). The effect of absorbed dose from 10 to 100 kGy, temperature (50, 60, and 70 {sup o}C), monomer concentration between 12.5% and 62.5%, monomers ratio from 10% to 90% and reaction time from 5 to 50 h; on the degree of grafting was determined. The grafted samples were analyzed by FTIR-ATR, TGA, DSC, swelling, and contact angle. Grafts onto polymeric films between 3% and 109% were obtained at doses from 10 to 100 kGy and a dose rate around 7.4 kGy/h. The graft percent increased with the content in HEMA in the HEMA:OEGMA feed mixture, which indicates a lower reactivity of OEGMA compared to HEMA. The hydrogel layer grafted on the polypropylene substrate increases the hydrophilicity of the surface and also provides certain temperature-responsiveness, which may be of interest for biomedical applications. - Highlights: > PP was grafted with a hydrogel layer applying the {gamma}-ray pre-irradiation method. > Effects of radiation dose, time, temperature and monomers concentration were evaluated. > Grafted layer increases the hydrophilicity of PP films. > HEMA and OEGMA grafted onto PP may be of interest for biomedical applications.

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.

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

Development of Less Water-Dependent Radiation Grafted Proton Exchange Membranes for Fuel Cells

Energy Technology Data Exchange (ETDEWEB)

Nasef, M M; Ahmad, A; Saidi, H; Dahlan, K Z.M. [Institute of Hydrogen Economy, Energy Research Alliance (ERA), International Campus, Univeristi Teknologi Malaysia, Jalan Semarak, Kuala Lumpur (Malaysia); Radiation Processing Division, Malaysian Nuclear Agency, Bangi, Kajang (Malaysia)

2012-09-15

The aim of these studies was the development of proton exchange membranes for polymer electrolyte membrane (PEM) fuel cell operated above 100{sup o}C, in order to obtain less water dependent, high quality and cheap electrolyte membrane. Sulfonic acid membranes were prepared by radiation induced grafting (RIG) of sodium styrene sulfonate (SSS) onto electron beam (EB) irradiated poly(vinylidene fluoride) (PVDF) films in a single step reaction for the first time using synergetic effect of acid addition to grafting mixture under various grafting conditions. The fuel cell related properties of the membranes were evaluated and the in situ performance was tested in a single H{sub 2}/O{sub 2} fuel cell under dynamic conditions and compared with a similar sulfonated polystyrene PVDF membrane obtained by two-step conventional RIG method i.e. grafting of styrene and subsequent sulfonation. The newly obtained membrane (degree of grafting, G% = 53) showed an improved performance and higher stability together with a cost reduction mainly as a result of elimination of sulfonation reaction. Acid-base composite membranes were also studied. EB pre-irradiated poly(ethylene-co-tetrafluoroethylene) (ETFE) films were grafted with N-vinyl pyridine (NVP). The effects of monomer concentration, dose, reaction time, film thickness, temperature and film storage time on G% were investigated. The membranes were subsequently doped with phosphoric acid under controlled condition. The proton conductivity of these membranes was investigated under low water conditions in correlation with the variation in G% and temperature (30-130{sup o}C). The performance of 34 and 49% grafted and doped membranes was tested in a single fuel cell at 130{sup o}C under dynamic conditions with 146 and 127 mW/cm{sup 2} power densities. The polarization, power density characteristics and the initial stability of the membrane showed a promising electrolyte candidate for fuel cell operation above 100 deg. C. (author)

Irradiation for xenogeneic transplantation

Energy Technology Data Exchange (ETDEWEB)

Halperin, E.C.; Knechtle, S.J.; Harland, R.C.; Yamaguchi, Yasua; Sontag, M.; Bollinger, R.R. (Duke Univ., Durham, NC (USA). Dept. of Radiology Duke Univ., Durham, NC (USA). Dept. of Microbiology and Immunology)

1990-05-01

Xenogeneic transplantation (XT) is the transplantation of organs or tissues from a member of one species to a member of another. Mammalian species frequently have circulating antibody which is directed against the foreign organ irrespective of known prior antigen exposure. This antibody may lead to hyperacute rejection once it ensues so efforts must be directed towards eliminating the pre-existing antibody. In those species in which hyperacute rejection of xenografts does not occur, cell-mediated refection, similar to allograft rejection, may occur. It is in the prevention of this latter form of refection that radiation is most likely to be beneficial in XT. Both total lymphoid irradiation (TLI) and selective lyphoid irradiation (LSI) have been investigated for use in conjunction with XT. TLI has contributed to the prolongation of pancreatic islet-cell xenografts from hamsters to rats. TLI has also markedly prolonged the survival of cardiac transplants from hamsters to rats. A more modest prolongation of graft survival has been seen with the use of TLI in rabbit-to-rat exchanges. Therapy with TLI, cyclosporine, and splenectomy has markedly prolonged the survival of liver transplants from hamsters to rats, and preliminary data suggest that TLI may contribute to the prolongation of graft survival in the transplantation of hearts from monkeys to baboons. SLI appears to have prolonged graft survival, when used in conjunction with anti-lymphocyte globulin, in hamster-to-rat cardiac graft exchanges. The current state of knowledge of the use of irradiaiton in experimental XT is reviewed. (author). 38 refs.; 1 fig.; 5 tabs.

Irradiation for xenogeneic transplantation

International Nuclear Information System (INIS)

Halperin, E.C.; Knechtle, S.J.; Harland, R.C.; Yamaguchi, Yasua; Sontag, M.; Bollinger, R.R.; Duke Univ., Durham, NC

1990-01-01

Xenogeneic transplantation (XT) is the transplantation of organs or tissues from a member of one species to a member of another. Mammalian species frequently have circulating antibody which is directed against the foreign organ irrespective of known prior antigen exposure. This antibody may lead to hyperacute rejection once it ensues so efforts must be directed towards eliminating the pre-existing antibody. In those species in which hyperacute rejection of xenografts does not occur, cell-mediated refection, similar to allograft rejection, may occur. It is in the prevention of this latter form of refection that radiation is most likely to be beneficial in XT. Both total lymphoid irradiation (TLI) and selective lyphoid irradiation (LSI) have been investigated for use in conjunction with XT. TLI has contributed to the prolongation of pancreatic islet-cell xenografts from hamsters to rats. TLI has also markedly prolonged the survival of cardiac transplants from hamsters to rats. A more modest prolongation of graft survival has been seen with the use of TLI in rabbit-to-rat exchanges. Therapy with TLI, cyclosporine, and splenectomy has markedly prolonged the survival of liver transplants from hamsters to rats, and preliminary data suggest that TLI may contribute to the prolongation of graft survival in the transplantation of hearts from monkeys to baboons. SLI appears to have prolonged graft survival, when used in conjunction with anti-lymphocyte globulin, in hamster-to-rat cardiac graft exchanges. The current state of knowledge of the use of irradiaiton in experimental XT is reviewed. (author). 38 refs.; 1 fig.; 5 tabs

Treatment of whole blood with riboflavin plus ultraviolet light, an alternative to gamma irradiation in the prevention of transfusion-associated graft-versus-host disease?

Science.gov (United States)

Fast, Loren D; Nevola, Martha; Tavares, Jennifer; Reddy, Heather L; Goodrich, Ray P; Marschner, Susanne

2013-02-01

Exposure of blood products to gamma irradiation is currently the standard of care in the prevention of transfusion-associated graft-versus-host disease (TA-GVHD). Regulatory, technical, and clinical challenges associated with the use of gamma irradiators are driving efforts to develop alternatives. Pathogen reduction methods were initially developed to reduce the risk of microbial transmission by blood components. Through modifications of nucleic acids, these technologies interfere with the replication of both pathogens and white blood cells (WBCs). To date, systems for pathogen and WBC inactivation of products containing red blood cells are less well established than those for platelets and plasma. In this study, the in vitro and in vivo function of WBCs present in whole blood after exposure to riboflavin plus ultraviolet light (Rb-UV) was examined and compared to responses of WBCs obtained from untreated or gamma-irradiated blood by measuring proliferation, cytokine production, activation, and antigen presentation and xenogeneic (X-)GVHD responses in an in vivo mouse model. In vitro studies demonstrated that treatment of whole blood with Rb-UV was as effective as gamma irradiation in preventing WBC proliferation, but was more effective in preventing antigen presentation, cytokine production, and T-cell activation. Consistent with in vitro findings, treatment with Rb-UV was as effective as gamma irradiation in preventing X-GVHD, a mouse model for TA-GVHD. The ability to effectively inactivate WBCs in fresh whole blood using Rb-UV, prior to separation into components, provides the transfusion medicine community with a potential alternative to gamma irradiation. © 2012 American Association of Blood Banks.

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

Chronic blood irradiation: a new approach

International Nuclear Information System (INIS)

Hungate, F.P.; Riemath, W.F.; Bunnell, L.R.; Gillis, M.F.

1976-01-01

Extracorporeal irradiation of blood is beneficial in suppressing early rejection of renal allografts and in treating chronic lymphocytic leukemia. Previously, nearly all blood irradiation has involved brief intermittent exposures with high dose rates. The small amount of data available involving chronic irradiation suggests that doses given chronically at lower rates are more effective in suppressing graft rejection. However, no suitably portable device has been available to permit chronic irradiation. This work has been directed toward developing a fully portable irradiator. After preliminary testing of a variety of source materials, 170 Tm was selected for its favorable beta energy, low cost, and compatibility with the fabrication requirements. The body of the irradiator is cast from polyfurfuryl alcohol with subsequent high-temperature conversion to vitreous carbon. By sequential layering of the alcohol and suspending of 169 Tm 2 O 3 in the midlayer, a unit is produced without any radiation exposure and with the source material contained on both a macro and a micro scale. Exposure of the unit to reactor neutrons produces 170 Tm without activation of the vitreous carbon. A 170 Tm irradiator giving a transit dose of 16 rads (100 ml/min flow) was connected in a carotid--jugular shunt on a 20-kg goat. Lymphocyte levels decreased to about 15 percent of the preexposure level during the first week and thereafter slowly rose to about 50 percent of preexposure levels 2 months after exposure. Reciprocal skin grafts made at the end of irradiation (12 days) were rejected at 12 days on the nonirradiated control and at 24 days on the irradiated goat. These results are consistent with data reported on chronically irradiated baboons even though the dose rate for the present test was only about one-fourth that for the baboons

The use of radiation-induced graft polymerization for modification of polymer track membranes

International Nuclear Information System (INIS)

Shtanko, N.I.; Kabanov, V.Ya.; Apel, P.Yu.; Yoshida, M.

1999-01-01

Track membranes (TM) made of poly(ethylene terephtalate) (PET) and polypropylene (PP) films have a number of peculiarities as compared with other ones. They have high mechanical strength at a low thickness, narrow pore size distribution, low content of extractables. However, TM have some disadvantages such as low chemical resistance in alkaline media (PET TM), the low water flow rate due to the hydrophobic nature of their surface. The use of radiation-induced graft polymerization makes it possible to improve the basic characteristics of TM. In this communication our results on the modification of PET and PP TM are presented. The modified membranes were prepared by radiation-induced graft polymerization from the liquid phase. Three methods of grafting were used: (a) the direct method in argon atmosphere; (b) the pre-irradiation of TM in air followed by grafting in argon atmosphere; (c) pre-irradiation in vacuum followed by grafting in vacuum without contacting oxygen. The aim of the work was to investigate some properties of TM modified by grafted poly(methylvinyl pyridine) (PMVP) and poly(N-isopropylacrylamide) (PNIPAAM). It was shown that the modification of TM with hydrophilic polymer results in the growth of the water flow rate. In the past few years many works have been devoted to the synthesis of new polymers - the so-called 'intelligent' materials - such as PNIPAAM. However, it is very difficult to make thin membranes of this polymer. Recently, it has been proposed to manufacture composite membranes by grafting stimulus-responsive polymers onto TM. Following this principle, we prepared thermosensitive membranes by the radiation-induced graft polymerization of N-isopropylacrylamide (NIPAAM) onto PET TM. PET TM with the pore size of about 1 μm and pore density of 10 6 cm -2 were first inserted into a solution of NIPAAM containing inhibitor of homopolymerization (CuCl 2 ) and then exposed to the γ-rays from a 60 Co source. The transport properties of the

The use of radiation-induced graft polymerization for modification of polymer track membranes

Science.gov (United States)

Shtanko, N. I.; Kabanov, V. Ya.; Apel, P. Yu.; Yoshida, M.

1999-05-01

Track membranes (TM) made of poly(ethylene terephtalate) (PET) and polypropylene (PP) films have a number of peculiarities as compared with other ones. They have high mechanical strength at a low thickness, narrow pore size distribution, low content of extractables. However, TM have some disadvantages such as low chemical resistance in alkaline media (PET TM), the low water flow rate due to the hydrophobic nature of their surface. The use of radiation-induced graft polymerization makes it possible to improve the basic characteristics of TM. In this communication our results on the modification of PET and PP TM are presented. The modified membranes were prepared by radiation-induced graft polymerization from the liquid phase. Three methods of grafting were used: (a) the direct method in argon atmosphere; (b) the pre-irradiation of TM in air followed by grafting in argon atmosphere; (c) pre-irradiation in vacuum followed by grafting in vacuum without contacting oxygen. The aim of the work was to investigate some properties of TM modified by grafted poly(methylvinyl pyridine) (PMVP) and poly(N-isopropylacrylamide) (PNIPAAM). It was shown that the modification of TM with hydrophilic polymer results in the growth of the water flow rate. In the past few years many works have been devoted to the synthesis of new polymers - the so-called "intelligent" materials - such as PNIPAAM. However, it is very difficult to make thin membranes of this polymer. Recently, it has been proposed to manufacture composite membranes by grafting stimulus-responsive polymers onto TM. Following this principle, we prepared thermosensitive membranes by the radiation-induced graft polymerization of N-isopropylacrylamide (NIPAAM) onto PET TM. PET TM with the pore size of about 1 μm and pore density of 10 6 cm -2 were first inserted into a solution of NIPAAM containing inhibitor of homopolymerization (CuCl 2) and then exposed to the γ-rays from a 60Co source. The transport properties of the grafted

Abrogation of genetically controlled resistance of mice to Treponema pallidum by irradiation

International Nuclear Information System (INIS)

Klein, J.R.; Monjan, A.A.; Hardy, P.H. Jr.; Cole, G.A.

1980-01-01

On intradermal infection, transient primary lesions, characteristic of those seen in naturally acquired human syphilis, can be produced regularly in some strains of mice but not others, indicating a genetic basis for host susceptibility. However strains of mice which normally fail to develop lesions, do so after exposure to ionising radiation. Here the importance of an intact immune system in the outcome of local infection is illustrated by the use of radiation-induced immunosuppression. The mice were exposed to lethal doses of total body irradiation from a 137 Ce source (137 rad per min), 850-1,050 rad depending on mouse strain. (UK)

Immunosuppressive effect of total lymphoid irradiation

International Nuclear Information System (INIS)

Bendel, V.; Medizinische Hochschule Hannover

1981-01-01

Contrary to the immunosuppression by means of wholebody irradiation which is known for a long while but connected with considerable side effects and risks, the total lymphoid irradiation (TLI) is a new possibility of immunosuppression the tolerance of which by man is known by virtue of long-standing experiences with the treatment of malignant lymphatic system diseases. In connexion with organ transplantations, TLI might possibly soon be important for the radiotherapeutist. In the experimentation on animals, the unspecific immunosuppression induced by TLI causes a prolonged survival time of allogeneic skin and organ grafts in certain mammals. Furthermore, a formation of blood chimeras combined with specific, permanent tolerance of organ grafts from the bone marrow donor can be caused by bone marrow transplantation after TLI. First experiences with man have been made. In the German literature, TLI has not been mentioned yet. In the present study, a summary is given on the Anglo-Saxon literature, and the first own experiments with regard to the problem of irradiation dose and transplantation interval are presented. (orig.) [de

Radiation grafting processes and properties of leathers modified with butyl acrylate

International Nuclear Information System (INIS)

Pietrucha, K.

1982-01-01

Conditions for radiation induced grafting with butyl acrylate dispersed in water emulsion onto chrome-tanned pig skins have been worked out for γ-rays and electron beam irradiations. The highest yield of grafting was observed at monomer concentration approximately 25% (w/w), dose equal to 25 kGy and dose rate not exceeding 10 MGy/h. At these conditions the yield of grafting attained a value approximately 25% and content of homopolymer in the leather amounted to 6%. The efficiency of monomer to polymer conversion decreases when the concentration of monomer in emulsion and dose rate increases. Yield of homopolymer is independent of the dose rate. An explanation of the observed relations has been proposed. The physical and used properties of grafted leathers were tested. Radiation processed leathers were found superior to samples finished by traditional methods. One has to point to better tolerance against chemical cleaning and reduced water take-up without loss of high permeability of water vapour, responsible for good hygienic properties of leather products. Recommendations for industrial scale radiation grafting are given. (author)

Improvement of blood compatibility of polyurethane elastomer by radiation graft copolymerization of 2-hydroxyethyl methacrylate in polymer matrix

International Nuclear Information System (INIS)

Li Ximing; Chen Wenming; Yuan Zhijian; Li Song; Lu Mei

1988-01-01

The γ-radiation induced grafting of 2-hydroxyethyl methacrylate (HEMA) onto polyurethane-elastomers (PUE) tube by preswelling technique to prepare biomedical materials with blood compatibility is studied. The graft yield can be controlled by regulating the preswelling time and temperature, or by change the irradiation dose and dose rate. After antithrombogenic test in vitro it has been confirmed that the blood compatibility of original polyurethane tube has been considerably improved by grafting

Study of Radiation Induced Radicals in HAP and β-TCP Based Bone Graft Materials by ERP Spectroscopy

International Nuclear Information System (INIS)

Maltar-Strmecki, N.; Matkovic, I.

2013-01-01

Calcium phosphates such as beta-tricalcium phosphate (β-TCP) and hydroxyapatite (HAP) are frequently used as dental implants due to proven excellent biocompatibility. Because of their resorption in the body and direct contact with tissues, in order to inactivate bacteria, fungal spores and viruses, they are usually sterilized by γ-irradiation. However, literature provides little information about effects of γ-irradiation on the formation and stability of the free radicals in the bone graft materials during and after sterilization procedure. In this study EPR (electron paramagnetic resonance) spectroscopy was used to investigate HAP and β-TCP based dental implants present on the market. Eight dental graft materials present on the market were investigated: Bioresorb R Macropore, Poresorb R -TCP, Easy-Graft T M and Cerasorb R synthetic β-tricalcium phosphates, Easy-Graft T M crystal and Ossceram R two phase synthetic CaP consisting of 60 % HAP and 40 % β-TCP, and Dexabone R and Bio-Oss R bone graft material of bovine origin. EPR study shows that this is the only technique for characterization of free radicals that can simultaneously determine not only the presence and content, but also the position and the structure of free radicals formed by γ-sterilization in the investigated materials, as well as the paramagnetic substitutions incorporated in the materials during the synthesis (such as Mn 2+ , Fe 3+ or Cr 2+ ). Additionally, EPR provides information on stability of irradiation-induced radicals (CO 2 - , trapped H-atoms, NO 3 2 etc.) and processes for reducing them. Results show that EPR should be considered as a valuable technique in improving the quality of bone graft materials, which must be sterile, and to offer the high quality, efficacy and reliable materials to the patients.(author)

Radiation initiated grafting of hydrophilic and reactive monomers on polyetherurethane for biomedical application

International Nuclear Information System (INIS)

Jansen, B.; Ellinghorst, G.

1981-01-01

Hydrogels such poly(hydroxyethylmethacrylate), poly (acrylamide) and poly(2,3-dihydroxypropylmethacrylate) are a class of well-known materials with good to excellent biomedical properties. Unfortunately the mechanical behaviour of the water-swollen gels is poor, and thus their application in pure state is limited. Much work has been done, especially by the grafting technique, on supporting the hydrogels by several techniques in order to improve their mechanical properties. In this work grafting of hydrogel forming or reactive monomers (which can be made hydrophilic by a following chemical process) onto a polyetherurethane was performed by a technique in which the trunk polymer is swollen in the graft monomer before irradiation. (author)

Antimicrobial and Thermal Properties of Metal Complexes of Grafted Fabrics with Acrylic Acid by Gamma Irradiation

International Nuclear Information System (INIS)

Hassan, M.S.; Attia, R.M.; Zohdy, M.H.

2008-01-01

Cotton, cotton/PET blend and PET fabrics were treated against microbial effect by radiation - induced grafting of acrylic acid followed by metal complexation with some divalent transition metal ions Co (II), Ni (II) and Cu (II). The microbial resistance was evaluated by testing the mechanical properties of the treated fabrics after burring for one and two weeks in a moist soil reach with microorganisms. Also, the growth of microorganisms was examined by scanning electron microscope (SEM). Moreover, the effect of this treatment on the thermal decomposition behavior was investigated by thermogravimetric analysis (TGA). On the basis of microbial studies, it was found that the metal complexation of the grafted fabrics with acrylic acid enhanced the antimicrobial resistance of the fabrics and the antimicrobial resistance could be arranged according to the metal ions as follows: copper> nickel> cobalt. Also, the thermal stability of different fabrics could be arranged as follow: grafted fabrics complexed with Cu (II) > grafted fabrics complexed with Ni (II) > grafted fabrics complexed with Co (II)

Synthesis of a pH- and Thermo- Responsive Binary Copolymer Poly(N-vinylimidazole-co-N-vinylcaprolactam Grafted onto Silicone Films

Directory of Open Access Journals (Sweden)

Ángela Obando-Mora

2015-10-01

Full Text Available This work focuses on the effects of gamma-ray irradiation conditions on the stimuli-responsiveness of silicone rubber (SR substrates grafted with N-vinylcaprolactam (NVCL and N-vinylimidazole (NVIM, modified by the simultaneously polymerization and grafting method, which is expected to result in valuable new applications in the near future. The modification of silicone rubber was carried out via γ-ray radiation in order to graft a binary copolymer, poly(N-vinylimidazole-co-N-vinylcaprolactam, by the pre-irradiation method, to obtain pH- and thermo-responsive materials. The grafting yield was found to be directly proportional to the dose and monomers concentration. The biomaterials were characterized by using Fourier-transform infrared attenuated total reflection (FTIR-ATR, differential scanning calorimetry (DSC, thermogravimetric analysis (TGA, and swelling; and their stimuli behavior was evaluated by lower critical solution temperature (LCST and pH critical studies.

Mechanical properties of human bone-tendon-bone grafts preserved by different methods and radiation sterilised

International Nuclear Information System (INIS)

Kaminski, A.; Gut, G.

2008-01-01

Full text: Patellar tendon auto and allografts are commonly used in orthopaedic surgery for reconstruction of the anterior crucial ligaments (ACL). Autografts are mainly used for primary reconstruction, while allografts are useful for revision surgery. To avoid the risk of infection diseases transmission allografts should be radiation-sterilised. As radiation-sterilisation is supposed to decrease the mechanical strength of tendon tissue, it is important to establish methods of allografts preservation and sterilisation resulting in their best quality and safety. Therefore, the purpose of the study was to compare the tensile strength of the central one third of human patellar tendon (as used for ACL reconstruction), preserved by different methods (deep fresh freezing, lyophilisation) and subsequently radiation-sterilised with doses of 0 (control), 25, 50 or 100 kGy. Bone-tendon-bone grafts were prepared from cadaveric human patella tendon with both patellar and tibial attachments. BTB grafts were preserved by deep freezing, glicerolisation or lyophilisation and radiation-sterilised with doses of 0 (control), 25, 50 or 100 kGy. To estimate mechanical properties all samples were subjected to tensile tests to failure using Instron system. Before these tests all lyophilised grafts were rehydrated. We found decrease of tensile strength of irradiated grafts compared to non-irradiated controls. Obtained results of the mechanical testing of studied grafts indicate their potential usefulness for clinical applications.(Author)

Synthesis of hemicellulose-acrylic acid graft copolymer super water absorbent resin by ultrasonic irradiation technology

Directory of Open Access Journals (Sweden)

Fangfang LIU

2015-12-01

Full Text Available The hemicellulose super water absorbent resin is prepared by using ultrasonic irradiation technology, with the waste liquid produced during the preparation of viscose fiber which contains a large amount of hemicellulose as raw material, acrylic acid as graft monomer, N,N’-methylene bis acrylamide (NMBA as cross linking agent, and (NH42S2O8-NaHSO3 as the redox initiation system. The synthesis conditions, structure and water absorption ability of resin are discussed. The results indicate that water absorbency of the resin is 311 g/g, the tap water absorbency is 102 g/g, the normal saline absorbency is 55 g/g, and the artificial urine absorbency is 31 g/g under the optimal synthesis conditions, so the resin has great water absorption rate and water retaining capacity. The FT-IR and SEM analysis shows that the resin with honeycomb network structure is prepared. The successfully synthesized of the resin means that the hemicellulose waste liquid can be highly effectively recycled, and it provides a kind of new raw material for the synthesis of super water absorbent resin.

Effects of solvents on the radiation grafting reaction of vinyl compounds on poly (3-hydroxybutyrate)

International Nuclear Information System (INIS)

Torres, Maykel González; Talavera, José Rogelio Rodríguez; Muñoz, Susana Vargas; Pérez, Manuel González; Castro, Ma. Pilar. Carreón.; Cortes, Jorge Cerna

2015-01-01

Vinyl Acetate was grafted onto poly (3-hydroxybutyrate) by the simultaneous gamma irradiation method using different types of solvents and in bulk (solvent free), at 10 kGy and 1.62 kGy/h dose and dose rate respectively. Subsequent complete hydrolysis allowed the conversion of grafted chains from poly (vinyl acetate) to poly (vinyl alcohol). The aim of this study is to determine the effect of solvent through the estimation of the dependence of the degree of grafting with the choice of solvent, the calculation of the degree of crystallinity, and to study the biodegradation of the products. The results showed a greater degree of grafting in bulk, while the more suitable solvent was hexane. Characterization of the grafted copolymer indicated that crystallinity percentage decreased by an increase in grafting, while the biodegradability was promoted by the increment in poly (vinyl alcohol) grafted. - Highlights: • PHB was indirectly grafted with PVA, by complete hydrolysis of grafted PVAc. • The effect of solvents on the grafting, crystallinity and biodegradation was studied. • The characterizations of the products were obtained by SEM, TGA, and DSC

An experimental studies of skin autograft in irradiated bed

International Nuclear Information System (INIS)

Ueda, Minoru

1981-01-01

Effects of irradiation to revascularization and skin grafting were studied. Wistar rats were irradiated with 1000, 2000, and 3000 rad of x-ray. One 2, 4, 6, 8, 12, and 24 weeks after irradiation each group, consisted of 10 rats, was compared with that of 34 untreated rats. A new score system of skin reaction was proposed. The highest moist skin reaction was observed after 2 weeks in 3 irradiated groups. In the 2000 and 3000 rad groups, the acute reaction appeared with 1 week latent period and recovered in 8 weeks followed by marked skin atrophy and epilation, while in the 1000 rad group complete recovery was observed in 3 weeks without late squlae. In order to carry out microangiography, a new device to inject the contrast medium at constant temperature and pressure was used. Marked inflammation was observed in 4 weeks, began to recover in 4 weeks, and hypovascular area appeared in 8 weeks. As for the blood area density, no variation was found for the 1000 rad group. However, in the 2000 and 3000 rad groups, the highest density was observed in 2 weeks and decreased after 8 weeks to that lower than the control. Revascularization after the skin grafting was followed by microangiography. In the control group, primary and secondary revascularization was observed one and 3 days after transplantation. As for the 3000 rad groups both revascularizations were hardly recognized when transplanted 8 weeks after irradiation. The optimum time for skin grafting was found to be acute or subacute period of the vascular damage. (Nakanishi, T.)

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)

Recommendations for the use of irradiated components

International Nuclear Information System (INIS)

2007-01-01

The disease 'graft-versus-host' associated with the transfusion (EIVH TA) is an adverse reaction rare but fatal, linked to the proliferation of T cells that are found in cellular components and reacting against the receptor's tissues). Gamma irradiation of cellular components is used as a prevention method because it deactivates the lymphocytes T by reducing its survival and by restraining its proliferation without producing alterations in others cells function. Recommendations for the use of gamma irradiation along with clinical indications for pediatric patients, patients with acquired immunosuppression and immunocompetent patients are given in this study. A brief description of operative aspects of irradiation procedures such as components to be irradiated, irradiation method, irradiation dose and viability of irradiated components is given [es

Total lymphoid irradiation and total body irradiation for allogeneic bone marrow transplantation in aplastic anemia

Energy Technology Data Exchange (ETDEWEB)

Kurisu, Koichi; Hishikawa, Yoshio; Taniguchi, Midori; Kamikonya, Norihiko; Miura, Takashi; Kanamaru, Akihisa; Kakishita, Eizo; Kai, Shunro; Hara, Hiroshi (Hyogo Coll. of Medicine, Nishinomiya (Japan))

Between April 1980 and June 1989, 15 patients with severe aplastic anemia (SAA) were treated at Hyogo College of Medicine with bone marrow transplantation (BMT) after preparation consisting of cyclophosphamide (CY) and total lymphoid irradiation (TLI) or total body irradiation (TBI) for the purpose of reducing the incidence of graft rejection. All patients had initial evidence of engraftment after the first transplantation except for one patient who died of heart failure due to CY on the third day after transplantation and could not be evaluated for engraftment. Rejection later occurred in four of these 14 patients, who then underwent successful regrafting. One of these four patients, who was conditioned with CY alone at the first grafting, underwent successful regrafting after a conditioning regimen of CY and TBI. In the other three patients, irradiation was performed twice as the conditioning regimen. Thus, 14 of 15 patients underwent successful BMT and are alive with restored hematopoietic function. From the above results, the combination of TLI or TBI and CY was considered to be very useful as a conditioning regimen for BMT in patients with SAA. (author).

Effect of blood transfusion and skin grafting on rats with combined radiation-burn injury

International Nuclear Information System (INIS)

Yan Yongtang; Ran Xinze; Wei Shuqing

1990-01-01

The therapeutic effect of escharectomy and skin grafting at different times on rats with combined radiation-burn injuries (5 Gy total body irradiation plus flash radiation from a 5 kW bromotungstenic lamp to induce a 15% TBSA full thickness burn on back) treated with blood transfusion (BT) were studied. The treatment with BT and escharectomy plus skin grafting at 24, 48, and 72 h after injury showed significant therapeutic effects. In these treated groups, early recovery of WBC counts, the granulocytes and total lymphocytes, T, B-cells, bone marrow cells or CFU-F counts were evident within 30 days after injury. The 30-day survival rates of the skin grafts in the group treated with BT and skin grafting at 24 h after injury was 80%, in the group with skin grafting alone was 50%, while all the skin grafts sloughted within 30 days when the grafting was performed 48 and 72 h after injury. The 30-day survival rate of the recipients treated with skin grafting plus BT was higher than that of the animals with skin grafting alone. The results showed that satisfactory results were achieved with BT plus escharectomy and skin grafting within 24 h after injury, while skin grafting performed at 48 or 72 h after injury was ineffective for the survival of skin grafts

The effect of γ-irradiation on changes of blood chemistry in RC-MAP after irradiation

International Nuclear Information System (INIS)

Hirose, Tetsuhito; Katayama, Norifumi; Okamoto, Yukiharu; Tsuda, Tadaaki; Ota, Kiichiro; Nishioka, Shingo; Tsumura, Michiyo; Yukawa, Mariko

1997-01-01

Irradiation to transfused blood is obligated to prevent from post transfusion graft-versus-host disease (PT-GVHD) by inactivation of lymphocytes. The rule of irradiated dose was not determined, it's dose being ranged from 15 to 50 Gy, but it's dose was done by each institute. We investigated an adequate dose of irradiation to blood on effects of plasma Na, potassium (K), Chloride (Cl), LDH, GOT, BUN and total protein (T.P) after irradiation of transfused blood. By comparison of plasma Na and K in non-irradiated blood, plasma K was increased and decreased in a parallelism of period of stored irradiated blood, two days after it's irradiation. Effects of Na and K levels were dose dependent. LDH level was increased in a time-dependency, but not by it's dose plasma Cl, LDH, GOT, BUN and T.P levels were not influenced. Our results indicated that the mechanism of RBC permeability after irradiation seemed to be inactivated Na-K ATPase activity in RBC cell membrane. (author)

Lung allograft rejection in the rat. I. Accelerated rejection caused by graft lymphocytes

International Nuclear Information System (INIS)

Prop, J.; Nieuwenhuis, P.; Wildevuur, C.R.

1985-01-01

To find out to what extent rejection of lungs differs from that of other organs, functional rejection of lung allografts was studied in five combinations of inbred rat strains. Rejection could be monitored accurately by perfusion scintigraphy, and equally well by chest roentgenography. The rejection of lung grafts was found to proceed remarkably fast, when compared with heart grafts, in combinations with strong RT1-incompatibilities. This accelerated rejection pattern could be converted into rejection at a normal pace by pretreatment of the donor with 10 Gy roentgen irradiation one day before transplantation. Donor pretreatment depleted the lung graft's bronchus-associated lymphoid tissue (BALT) of lymphocytes. When grafts were depleted of all other passenger cells as well--by retransplantation from a cyclosporine-treated intermediate host--they showed an even more reduced immunogenicity, probably because of the loss of donor-type dendritic cells. These results indicate that lymphocytes from the BALT of lung grafts are capable of accelerating the rejection response

Beclin1-induced autophagy abrogates radioresistance of lung cancer cells by suppressing osteopontin

International Nuclear Information System (INIS)

Chang, Seung-Hee; Minai-Tehrani, Arash; Shin, Ji-Young

2012-01-01

Osteopontin (OPN) serves as an indicator of resistance to radiotherapy. However, the role of OPN in the development of acquired radioresistance in human lung cancer cells has not yet been fully elucidated. Therefore, the potential importance of OPN as a marker of lung cancer with a potential significant role in the development of radioresistance against repeated radiotherapy has prompted us to define the pathways by which OPN regulates lung cancer cell growth. In addition, autophagy has been reported to play a key role in the radiosensitization of cancer cells. Here, we report that increased OPN expression through induction of nuclear p53 following irradiation was inhibited by exogenous beclin-1 (BECN1). Our results clearly show that BECN1 gene expression led to induction of autophagy and inhibition of cancer cell growth and angiogenesis. Our results suggest that the induction of autophagy abrogated the radioresistance of the cancer cells. Interestingly, we showed that knockdown of OPN by lentivirus-mediated shRNA induced the autophagy of human lung cancer cell. Taken together, these results suggest that OPN and BECN1 can be molecular targets for overcoming radioresistance by controlling autophagy. (author)

Dyed grafted films for large-dose radiation dosimetry

Energy Technology Data Exchange (ETDEWEB)

Abdel Rehim, F; El-Sawy, N M; Abdel-Fattah, A A [National Centre for Radiation Research and Technology, Cairo (Egypt)

1993-07-01

By radiation-induced polymerization of acrylic acid onto poly(ethylene-tetrafluoroethylene) (ET) copolymer film and reacting the resulted grafted film with both Rhodamine B (RB) and Malachite Green (MG), new dosimeter films have been developed for high-dose gamma radiation applications in the range of absorbed doses from 10 to 180 kGy. The radiation-induced color bleaching has been analysed with visible spectrophotometry, either at the maximum of the absorption band peaking at 559 nm (for ETRB) or that peaking at 627 nm (for ETMG). The effects of different conditions of absorbed dose rate, temperature and relative humidity during irradiation and post-irradiation storage on dosimeter performance are discussed. (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.

Exogenous modulation of TGF-β1 influences TGF-βR-III-associated vascularization during wound healing in irradiated tissue

International Nuclear Information System (INIS)

Wehrhan, F.; Schultze-Mosgau, S.; Grabenbauer, G.G.; Roedel, F.; Amann, K.

2004-01-01

Background and purpose: Following preoperative radiotherapy prior to ablative surgery of squamous epithelial cell carcinomas of the head and neck region, wound-healing disorders occur. Previous experimental studies showed altered expression of transforming growth factor-(TGF-)β isoforms following surgery in irradiated graft beds. Altered levels of TGF-β 1 are reported to promote fibrosis and to suppress vascularization during wound healing, whereas expression of TGF-β receptor-III (TGF-βR-III) is associated with vascularization. The aim of the study was to analyze the influence of anti-TGF-β 1 treatment on TGF-βR-III-associated vascularization in the transition area between irradiated graft bed and graft. Material and methods: Wistar rats (male, weight 300-500 g) underwent preoperative irradiation of the head and neck region with 40 Gy (four fractions of 10 Gy each; n=16 animals). A free myocutaneous gracilis flap taken from the groin was then transplanted to the neck in all rats. The time interval between operation and transplantation was 4 weeks. Eight animals received 1 μg anti-TGF-β 1 into the graft bed by intradermal injection on days 1-7 after surgery. On days 3, 7, 14, 28, 56, and 120, skin samples were taken from the transition area between transplant and graft bed and from the graft bed itself. Immunohistochemistry was performed using the ABC-POX method to analyze the TGF-βR-III and E-selection expression. Histomorphometry was performed to analyze the percentage and the area of positively stained vessels. Results: A significantly higher expression of TGF-βR-III was seen in the irradiated and anti-TGF-β 1 -treated graft bed in comparison to the group receiving preoperative irradiation followed by transplantation alone. The percentage of TGF-βR-III positively staining capillaries from the total amount of capillaries in the anti-TGF-β 1 -treated graft bed was higher than in the group irradiated only. The total area of capillaries was also higher

Graft polymerization of acrylic acid and methacrylic acid onto poly(vinylidene fluoride) powder in presence of metallic salt and sulfuric acid

Science.gov (United States)

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

2011-02-01

Poly(vinylidene fluoride) (PVDF) powder was grafted with acrylic acid (AAc) or methacrylic acid (MAA) by the pre-irradiation induced graft polymerization technique. The presence of graft chains was proven by FT-IR spectroscopy. The degree of grafting (DG) was calculated by the acid-base back titration method. The synergistic effect of acid and Mohr's salt on the grafting kinetics was examined. The results indicated that adding sulfuric acid and Mohr's salt simultaneously in AAc or MAA solutions led to a strong enhancement in the degree of grafting. The grafted PVDF powder was cast into microfiltration (MF) membranes using the phase inversion method and some properties of the obtained MF membranes were characterized.

Graft polymerization of acrylic acid and methacrylic acid onto poly(vinylidene fluoride) powder in presence of metallic salt and sulfuric acid

Energy Technology Data Exchange (ETDEWEB)

Deng Bo [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, No. 2019, Jialuo Road, Jiading Dist., 201800 Shanghai (China); Yu Yang; Zhang Bowu; Yang Xuanxuan [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, No. 2019, Jialuo Road, Jiading Dist., 201800 Shanghai (China); Graduate University of Chinese Academy of Sciences, No. 19, Yuquan Road, Shijingshan Dist., 100049 Beijing (China); Li Linfan; Yu Ming [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, No. 2019, Jialuo Road, Jiading Dist., 201800 Shanghai (China); Li Jingye, E-mail: jingyeli@sinap.ac.c [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, No. 2019, Jialuo Road, Jiading Dist., 201800 Shanghai (China)

2011-02-15

Poly(vinylidene fluoride) (PVDF) powder was grafted with acrylic acid (AAc) or methacrylic acid (MAA) by the pre-irradiation induced graft polymerization technique. The presence of graft chains was proven by FT-IR spectroscopy. The degree of grafting (DG) was calculated by the acid-base back titration method. The synergistic effect of acid and Mohr's salt on the grafting kinetics was examined. The results indicated that adding sulfuric acid and Mohr's salt simultaneously in AAc or MAA solutions led to a strong enhancement in the degree of grafting. The grafted PVDF powder was cast into microfiltration (MF) membranes using the phase inversion method and some properties of the obtained MF membranes were characterized.

Graft polymerization of acrylic acid and methacrylic acid onto poly(vinylidene fluoride) powder in presence of metallic salt and sulfuric acid

International Nuclear Information System (INIS)

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

2011-01-01

Poly(vinylidene fluoride) (PVDF) powder was grafted with acrylic acid (AAc) or methacrylic acid (MAA) by the pre-irradiation induced graft polymerization technique. The presence of graft chains was proven by FT-IR spectroscopy. The degree of grafting (DG) was calculated by the acid-base back titration method. The synergistic effect of acid and Mohr's salt on the grafting kinetics was examined. The results indicated that adding sulfuric acid and Mohr's salt simultaneously in AAc or MAA solutions led to a strong enhancement in the degree of grafting. The grafted PVDF powder was cast into microfiltration (MF) membranes using the phase inversion method and some properties of the obtained MF membranes were characterized.

Swelling properties of cassava starch grafted with poly (potassium acrylate-co-acrylamide) superabsorbent hydrogel prepared by ionizing radiation

Science.gov (United States)

Barleany, Dhena Ria; Ulfiyani, Fida; Istiqomah, Shafina; Heriyanto, Heri; Rahmayetty, Erizal

2015-12-01

Natural and synthetic hydrophylic polymers can be phisically or chemically cross-linked in order to produce hydrogels. Starch based hydrogels grafted with copolymers from acrylic acid or acrylamide have become very popular for water absorbent application. Superabsorbent hydrogels made from Cassava starch grafted with poly (potassium acrylate-co-acrylamide) were prepared by using of ϒ-irradiation method. Various important parameters such as irradiation doses, monomer to Cassava starch ratio and acrylamide content were investigated. The addition of 7,5 % w w-1 acrylamide into the reaction mixture generated a starch graft copolymer with a water absorption in distilled water as high as 460 g g-1 of its dried weight. The effectivity of hydrogel as superabsorbent for aqueous solutions of NaCl and urea was evaluated. The obtained hydrogel showed the maximum absorptions of 317 g g-1 and 523 g g-1 for NaCl and urea solution, respectively (relative to its own dry weight). The structure of the graft copolymer was analyzed by using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM).

Surface modification of poly(styrene-b-(ethylene-co-butylene)-b-styrene) elastomer via photo-initiated graft polymerization of poly(ethylene glycol)

Energy Technology Data Exchange (ETDEWEB)

Li Xiaomeng [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Luan Shifang, E-mail: sfluan@ciac.jl.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Yang Huawei; Shi Hengchong; Zhao Jie; Jin Jing [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Yin Jinghua, E-mail: yinjh@ciac.jl.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Stagnaro, Paola [Istituto per Io Studio delle Macromolecole, Consiglio Nazionale delle Ricerche, Via de Marini 6, 16149 Genova (Italy)

2012-01-15

Poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) copolymer biomedical elastomer was covalently grafted with poly(ethylene glycol) methyl ether methacrylate (PEGMA) via a photo-initiated graft polymerization technique. The surface graft polymerization of SEBS with PEGMA was verified by ATR-FTIR and XPS. Effect of graft polymerization parameters, i.e., monomer concentration, UV irradiation time and initiator concentration on the grafting density was investigated. Comparing with the virgin SEBS film, the PEGMA-modified SEBS film presented an enhanced wettability and a larger surface energy. Besides, the surface grafting of PEGMA imparted excellent anti-platelet adhesion and anti-protein adsorption to the SEBS surface.

Comparative studies in the cellular immunostimulation by whole body irradiation. Vergleichende Untersuchungen ueber die zellulaere Immunstimulation durch Ganzkoerperbestrahlung

Energy Technology Data Exchange (ETDEWEB)

Dietz, R.; Schwarze, G. (Service de Radiologie, Centre Hospitalier de Luxembourg (Luxembourg) Medizinische Universitaetsklinik I, Homburg/Saar (Germany))

1992-04-01

The effect of the cellular immune response by total body irradiation was investigated. The transplant survival (skin grafts) was determined as immune parameter. Donors were colony bred Wistar rats and recipients were colony bred Sprague Dawley rats. The investigations were carried out with irradiated rats and with rats irradiated after thymectomy and/or adrenalectomy as well as with animals without irradiation. A single total-body irradiation (1 and 2 Gy) was administered. The skin graft survival in irradiated rats was significant shorter (radiogenic immunostimulation) than in unirradiated rats; there were no significant differences between the operated (thymectomy and/or adrenalectomy) and not operated animals. Including precedent examinations this radiogenic immunostimulation is caused by relativly selective inactivation of T-suppressor cells. (orig.).

The Use Of Laser Irradiation To Stimulate Adipose Derived Stem Cell Proliferation And Differentiation For Use In Autologous Grafts

Science.gov (United States)

Abrahamse, Heidi

2009-09-01

fluences on ADSC viability and proliferation. This paper reviews the development of MSCs as potential therapeutic interventions such as autologous grafts as well as the contribution of low intensity laser irradiation on the maintenance of these cells.

Blood irradiation

International Nuclear Information System (INIS)

Chandy, Mammen

1998-01-01

Viable lymphocytes are present in blood and cellular blood components used for transfusion. If the patient who receives a blood transfusion is immunocompetent these lymphocytes are destroyed immediately. However if the patient is immunodefficient or immunosuppressed the transfused lymphocytes survive, recognize the recipient as foreign and react producing a devastating and most often fatal syndrome of transfusion graft versus host disease [T-GVHD]. Even immunocompetent individuals can develop T-GVHD if the donor is a first degree relative since like the Trojan horse the transfused lymphocytes escape detection by the recipient's immune system, multiply and attack recipient tissues. T-GVHD can be prevented by irradiating the blood and different centers use doses ranging from 1.5 to 4.5 Gy. All transfusions where the donor is a first degree relative and transfusions to neonates, immunosuppressed patients and bone marrow transplant recipients need to be irradiated. Commercial irradiators specifically designed for irradiation of blood and cellular blood components are available: however they are expensive. India needs to have blood irradiation facilities available in all large tertiary institutions where immunosuppressed patients are treated. The Atomic Energy Commission of India needs to develop a blood irradiator which meets international standards for use in tertiary medical institutions in the country. (author)

Obtention of graft copolymers by ionizing radiation, characterization and study of hemo-compatible properties; Obtencao de copolimeros de enxerto via radiacao ionizante, caracterizacao e estudo de suas propriedades hemocompativeis

Energy Technology Data Exchange (ETDEWEB)

Queiroz, A A.A. de

1994-12-31

The present work had as objectives the obtention and characterization of grafting copolymers by radiation induced polymerization and the study of its hemo compatible properties. The relationship between grafting conditions and anti-trombogenicity was examined for the purpose of clearing the necessity of controlling grafting conditions to enhance the copolymers blood compatibility. Two methods were chosen to accomplish the irradiation: mutual and pre-irradiation (peroxidation) of the films in {sup 6O} Co source and electron beam accelerator. Primarily grafting parameters were studied in the systems of the monomers N, N-dimethyl acrylamide (DMAA) and acrylic acid (AA) with the polymeric films: poly (tetrafluoroethylene) (PTFE), poly (ethylene-co-tetrafluoroethylene) (PETFE), low density polyethylene (LDPE) and poly (vinyl chloride) (PVC). The simultaneous irradiation was effective in the polymerization of all the substrates above mentioned, although the peroxidation method has given better results for PETFE-DMAA, LDPE-g-DMAA, LDPE-g-AA and PVC-g-AA. In the system AA/LDPE and AA/PVC the homo polymerization was controlled by the addition of the comonomer N, N-dimethyl acrylic acid (DMA). As for the grafting parameters, low dose rate and low irradiation dose, showed to be very effective for the graftability of DMAA and AA on the substrates. (author). 129 refs, 51 figs, 7 tabs.

Poly-electrolyte fuel cell membrane based on crosslinked polytetrafluoroethylene by radiation-grafting

International Nuclear Information System (INIS)

Ichizuri, Shogo; Asano, Saneto; Li, Jingye

2004-01-01

Poly-electrolyte fuel cell (PEFC) membranes based on crosslinked Polytetrafluoroethylene (RX-PTFE) have been fabricated by radiation-grafting with reactive styrene monomers using γ-ray irradiation in air at room temperature / electron beam irradiation under N 2 gas atmosphere at room temperature. The characteristic properties of obtained materials have been measured by DSC, TGA and FT-IR spectroscopy, and so on. Ion exchange capacity of sulfonated crosslinked PTFE has been achieved 2.8meq/g. (author)

Influence of the thymus on the capacity of female mice to reject male skin grafts

International Nuclear Information System (INIS)

De Pirro, E.S.; Goldberg, E.H.

1989-01-01

The ability of female mice to reject H-Y-incompatible, but otherwise histocompatible, male skin grafts differs greatly from strain to strain, as is illustrated particularly by the C57BL strain (B6 and other sublines), termed ''H-Y rejector,'' because females invariably and promptly reject C57BL male skin, in comparison with the C3H strain, termed ''H-Y nonrejector,'' because females characteristically accept male C3H skin. To assess the extent to which the thymus governs this rejector vs. nonrejector status, two studies were made. In the first, lethally irradiated B6 (C57BL) and C3H females were restored with (B6 X C3H)F1 female cells, providing a graft-vs.-host-free milieu for differentiation of the same immunopoietic cell population in B6 vs. C3H hosts. With respect to (B6 X C3H)F1 male skin grafts, B6 hosts responded as rejectors and C3H hosts as nonrejectors, signifying that rejector vs. nonrejector status was determined by the host during immunopoiesis. That the main organ responsible for rejector vs. nonrejector determination is the thymus was shown in a second study. Previously thymectomized (B6 X C3H)F1 females received a histocompatible graft of thymus from either B6 or C3H neonatal females and were restored with donor-marked (B6-Ly-5a X C3H)F1 female cells after lethal irradiation. With respect to (B6 X C3H)F1 male skin grafts, the recipients of B6 thymus grafts responded generally as rejectors and the recipients of C3H thymus grafts responded uniformly as nonrejectors

Development of Graft Copolymer Flocculant Based on Acrylamide and Acrylic Acid for the dewatering of coal

International Nuclear Information System (INIS)

Mahmoud, G.A.; Abdel Khalek, M.A

2012-01-01

Most coal preparation processes were carried out in water medium. The water content of coal product has a negative impact on handling and specific energy value. The moisture content may be attributed to the proportion of fine coal, which presents the greatest dewatering problem. A novel polymeric flocculant has been developed by graft copolymerization of acrylamide (AAm) with acrylic acid (AAc) using gamma irradiation technique. The grafted copol621621ymer P(AAm/AAc) was characterized by Fourier-transform infrared spectroscopy (FTIR), and thermo-gravimetric analysis (TGA). The effects of reaction parameters, such as total absorbed dose, and monomer concentration on grafting yield were investigated. The flocculation performance of the graft copolymer P(AAm/AAc) was investigated in coal suspension. It was observed that the grafting ratio was one of the key factors for the flocculating effects. The copolymers with various grafting ratios showed different flocculating properties. It was found that as the grafting ratio increased, the flocculating effect also increased. The flocculation performance of the grafted copolymer was better than that of the commercial flocculant, poly-acrylamide (Magnafloc 1011).

Radiation-grafting of flame retardants on flax fabrics - A comparison between different flame retardant structures

Science.gov (United States)

Teixeira, Marie; Sonnier, Rodolphe; Otazaghine, Belkacem; Ferry, Laurent; Aubert, Mélanie; Tirri, Teija; Wilén, Carl-Eric; Rouif, Sophie

2018-04-01

Three unsaturated compounds bearing respectively phosphate, aryl bromide and sulfenamide moieties were used as flame retardants (FR) for flax fabrics. Due to the presence of carbon-carbon double bonds, radiation-grafting was considered to covalently bond these FR onto fiber structure. Grafting efficiency and location of FR molecules were investigated by weight measurements and SEM-EDX observations. Flammability and especially self-extinguishment were assessed by thermogravimetric analysis, pyrolysis-combustion flow calorimetry and a non-standardized fire test already used in previous studies. All FRs were able to diffuse into elementary fiber bulk. Nevertheless only the phosphonated monomer (noted FR-P) was significantly grafted onto flax. Self-extinguishment was obtained for fabrics containing at least around 0.5 wt% of phosphorus. On the contrary the FR content of flax fibers after radiation-grafting procedure and washing was negligible for FR-S and FR-Br, evidencing that these molecules have not been grafted upon irradiation. Moreover, the combination of these molecules prevents the radiation-grafting of other molecules which showed good grafting rate when used alone.

Electron beam induced graft-polymerization of methyl methacrylate onto polyethylene films at high dose rates

International Nuclear Information System (INIS)

Mori, Koji; Koshiishi, Kenji; Masuhara, Ken-ichi

1991-01-01

Electron beam induced graft-polymerization by the mutual irradiation technique of methyl methacrylate on the surface of low density polyethylene films (LD) and high density polyethylene films (HD) was investigated at high dose rates over 10 Mrad per second. Graft-polymerization mechanisms were discussed on the basis of O 2 permeability, tensile strength, elongation at break, and surface tension of the grafted films. As the degree of grafting increased, the O 2 permeability of LD decreased, while that of HD little changed at the grafting up to 4 ∼ 5 %. This indicates that the grafting occurred in the amorphous regions for LD and occurred in the amorphous regions in the neighborhood of crystalline regions for HD. For HD, when the degree of the grafting surpassed 4 ∼ 5 %, the O 2 permeability, tensile strength, elongation at break, and surface tension decreased with an increase in the degree of grafting. It was assumed that rapid grafting in the amorphous regions in the neighborhood of crystalline regions caused the increase in local temperature by the heat of polymerization, and the viscosity of polyethylene in the amorphous regions decreased with an increase in temperature. As a result, the graft chains, which formed micro domain structure, condensed in the amorphous regions and the domain increased in size. (author)

Permeability of solutes through cellophanes grafted with vinyl monomers. I. Diffusion of potassium chloride, urea, and uric acid

International Nuclear Information System (INIS)

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

1979-01-01

The diffusive permeability of potassium chloride, urea, and uric acid through cellophanes grafted with acrylamide, acrylic acid, styrene, and N-vinyl-2-pyrrolidone by γ-ray irradiation was studied. The diffusive permeability coefficients of the permeants through the grafted cellophanes were increased with increase in hydration of the grafted membranes, except for the permeation of potassium chloride through cellophanes grafted with acrylic acid. The permeation of potassium chloride, urea, and uric acid through the various grafted cellophanes is explained by the free volume concept of homogeneously water-swollen membranes. However, the behavior of the permeation of potassium chloride through cellophane grafted with acrylic acid deviated from that of nonionic membranes because of the contribution of the electrical interaction between electrolyte and charge of the membrane. 4 figures, 3 tables

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)

Effect of 60Co radiation-induced grafting of methyl methacrylate on mechanical properties of bamboo

International Nuclear Information System (INIS)

Zhang Hao; Zhou Liang; Liu Shengquan; Qian Liangcun; Fei Benhua; Jiang Zehui

2011-01-01

In order to investigate the effect of radiation grafting on mechanical properties of bamboo, the original and carbonized bamboo soaked with monomer MMA were radiation grafted by 60 Co γ rays with the doses of 60-220 kGy. The results showed that compared with original blanks, treated with MMA and irradiated with the dose of 180 kGy the specific gravity, bending strength modulus of elasticity of original bamboo increased by 6.7%, 4.4%, and 28%, meanwhile its oven-dried radial, tangential and volumetric shrinkage decreased by 38.9%, 47.4%, and 32.9%, respectively. What is more, treated with MMA and irradiated with the doses of 140 kGy the specific gravity and modulus of elasticity of carbonized bamboo increased by 6.8% and 20%, while its oven-dried radial, tangential, volumetric shrinkage decreased by 11%, 4.6% and 12%, respectively. The study reveals that mechanical properties of original and carbonized bamboo can be enhanced by radiation grafting copolymerization with suitable absorbed doses, which may be valuable for the further research of developing new bamboo plastic composites. (authors)

Practical dosimetric aspects of blood and blood product irradiation

International Nuclear Information System (INIS)

Fearon, T.C.; Luban, N.L.

1986-01-01

The method of choice to reduce susceptibility to transfusion-transmitted graft-versus-host disease is irradiation of allogenic blood and blood products for transfusion to immunosuppressed recipients. Optimal irradiation requires delivery of a known and homogeneous absorbed dose. The use of absorbed dose in air measured at the center of the irradiation volume without proper compensation for sample absorption can lead to approximately 20 percent underexposure. A lucite cylinder was used to provide the delivery of a homogeneous irradiation dose to blood products of different volumes by allowing rotation of the product

Preparation of pH-sensitive poly(ethylene oxide) hydrogels grafted by γ-ray irradiation and their applications for drug delivery system

International Nuclear Information System (INIS)

Nho, Y.-C.; Kang, P.-H.; Lim, Y.-M.; Kuk, I.-H.

2006-01-01

undesirable. Oral delivery of peptides, proteins and other drugs to the gastrointestinal (GI) tract is one of the most challenging issues, and thus, under much investigation. There are many hurdles, including protein inactivation by digestive enzymes in the GI tract, and the poor epithelial permeability of these drugs. Certain hydrogels may overcome some of these problems by appropriate molecular design or formulation approaches. In this study, pH-sensitive hydrogels were studied as a drug carrier for the protection of insulin from the acidic environment of the stomach before releasing it in the small intestine. Hydrogels based on poly(ethylene oxide) (PEO) networks grafted with methacrylic acid (MAA) or acrylic acid (AAc) were prepared via a two-step process. PEO hydrogels were prepared by gamma-ray irradiation (radiation dose: 50 kGy, does rate: 7.66 kGy/h), and then grafting by either MAA or AAc monomers onto the PEO hydrogels with subsequent irradiation (radiation dose: 5-20 kGy, dose rate: 2.15 kGy/h). These grafted hydrogels showed a pH-sensitive swelling behavior. The grafted hydogels were used as a carrier for the drug delivery systems for the controlled release of insulin. Drug-loaded hydrogels were placed in simulated gastric fluid (SGF, pH 1.2) for 2 hr and then in simulated intestinal fluid (SIF, pH 6.8). The in vitro drug release behaviors of these hydrogels were examined by quantification analysis with a UV/vis spectrophotometer. The equilibrium swelling measurements of these hydrogels, which were carried out in simulated gastrointestinal fluids, showed a pH-sensitive nature. The in vitro release profiles of the drugs were obtained in both a simulated gastric fluid and simulated intestinal fluid. The release behavior of the pH-sensitive PEO-g-MAA and PEO-g-AAc hydrogels indicated that these gels could be applied successfully for oral drug delivery to the gastrointestinal tract. . (authors)

Skin graft

Science.gov (United States)

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 ...

Specific allogeneic unresponsiveness in irradiated dogs reconstituted with autologous bone marrow

International Nuclear Information System (INIS)

Rapaport, F.T.; Bachvaroff, R.J.; Akiyama, N.; Sato, T.; Ferrebee, J.W.

1980-01-01

Hemopoietic reconstitution of supralethally irradiated adult dogs of the Cooperstown colony with their own stored bone marrow can produce long-term unresponsiveness to DLA-identical kidney allografts with no need for any additional immunosuppression. Eleven of 18 kidneys transplanted 12 h after replacement of autologous marrow into irradiated recipients currently survive with normal function for as long as 1417 d; 8 of 13 organs transplanted 28 h after marrow replacement, and 8 of 13 organs transplanted 36 h after marrow injection, currently survive up to 502 d, with no further treatment. Alterations in the timing and sequence of each procedure decrease the incidence of unresponsiveness. Survival and function of the kidney allografts were not affected by the rejection of successive skin grafts from the kidney donor. Skin grafts from other DLA-identical donors and DLA-incompatible skin grafts were rejected by the same recipients in uniform fashion

Experimental study on lyophilized irradiation sterilized nerve allografts in rabbits

International Nuclear Information System (INIS)

Yang Zhiyuan; Sun Shiquan; Liu Hechen

1991-01-01

Lyophilized irradiation sterilized nerve grafts in rabbits were used in allogeneic nerve transplantation. The result show that about 76% of experimental rabbits had fairly well morphologic (microscopic and electron microscopic) and electrophysiological recovery 3 month after operation. Preservation of neurilemmal tubes in nerve grafts, repopulation of Schwann cells in this tube and suppression of immune rejection are the key points in allogeneic nerve transplantation

Radiation-Induced Grafting for the Synthesis of Adsorbents for Phosphate and Chromate Removal from Aqueous Systems

Energy Technology Data Exchange (ETDEWEB)

Kavakli, P A; Kavakli, C; Guven, O [Department of Chemistry, Hacettepe University, Beytepe, 06800, Ankara (Turkey)

2012-09-15

Nonwoven fabrics made of PE coated PP fibres were irradiated by accelerated electrons in inert atmospheres for grafting of two different monomers, glycidyl methacrylate and dimethylaminoethyl methacrylate. Grafting conditions were optimized by a systematic investigation of the effects of absorbed dose, monomer concentration, grafting reaction temperature and duration. 150% grafted copolymers were later modified by protonation and quaternization of poly(dimethylaminoethyl methacrylate) chains and by Cu(II) loading of dipyridyl amine modified poly(glycidyl methacrylate) graft chains. The PE/PP based adsorbents thus prepared were used for their suitability of removing phosphate and chromate ions from aqueous systems. Adsorption/removal studies were carried out in both batch and continuous flow type systems. The selectivity of adsorption of phosphate ions in the presence of other competing anions were also checked showing the enhanced selectivity for phosphate ions. (author)

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.

Clinical and immunologic effects of fractionated total lymphoid irradiation in refractory rheumatoid arthritis

International Nuclear Information System (INIS)

Trentham, D.E.; Belli, J.A.; Anderson, R.J.; Buckley, J.A.; Goetzl, E.J.; David, J.R.; Austen, K.F.

1981-01-01

Ten patients with refractory rheumatoid arthritis were given 3000 rad of fractionated total lymphoid irradiation in an uncontrolled therapeutic trial. Total lymphoid irradiation was associated with objective evidence of considerable clinical improvement in eight patients and with reduced blood lymphocyte counts in all 10. On completion of irradiation, there was an abrogation of lymphocyte reactivity in vitro in the patients with clinical responses, but abnormal antibody activities characteristic of rheumatoid arthritis and normal components of humoral immunity were not suppressed. Partial recrudescence of arthritis occurred shortly after a year after the completion of irradiation and was paralleled by a restitution of lymphocyte concentrations and responsiveness to mitogens to levels similar to those observed before irradiation. These data provide further evidence of T-cell involvement in the pathogenesis of rheumatoid arthritis and demonstrate that total lymphoid irradiation can induce temporary relief, but they do not ascertain whether the natural history of this disease was altered

Clinical and immunologic effects of fractionated total lymphoid irradiation in refractory rheumatoid arthritis

International Nuclear Information System (INIS)

Trentham, D.E.; Belli, J.A.; Anderson, R.J.; Buckley, J.A.; Goetzl, E.J.; David, J.R.; Austen, K.F.

1981-01-01

Ten patients with refractory rheumatoid arthritis were given 3000 rad of fractionated total lymphoid irradiation in an uncontrolled therapeutic trial. Total lymphoid irradiation was associated with objective evidence of considerable clinical improvement in eight patients and with reduced blood lymphocyte counts in all 10. On completion of irradiation, there was an abrogation of lymphocyte reactivity in vitro in the patients with clinical responses, but abnormal antibody activities characteristic of rheumatoid arthritis and normal components of humoral immunity were not suppressed. Partial recrudescence of arthritis occurred shortly before a year after the completion of irradiation and was paralleled by a restitution of lymphocyte concentrations and responsiveness to mitogens to levels similar to those observed before irradiation. These data provide further evidence of T-cell involvement in the pathogenesis of rheumatoid arthritis and demonstrate that total lymphoid irradiation can induce temporary relief, but they do not ascertain whether the natural history of this disease was altered

The tolerance of skin grafts to postoperative radiation therapy in patients with soft-tissue sarcoma

International Nuclear Information System (INIS)

Lawrence, W.T.; Zabell, A.; McDonald, H.D.

1986-01-01

During the last ten years at the National Cancer Institute, 11 patients have received 12 courses of postoperative adjuvant radiation therapy to skin grafts used for wound closure after the resection of soft-tissue sarcomas. The intervals between grafting and the initiation of radiation ranged between 3 and 20 weeks, and 4 patients received chemotherapy at the same time as their radiation. Ten of the 12 irradiated grafts remained intact after the completion of therapy. One graft had several small persistently ulcerated areas that required no further surgical treatment, and one graft required a musculocutaneous flap for reconstruction of a persistent large ulcer. Acute radiation effects on the grafted skin sometimes developed at slightly lower doses than usually seen with normal skin, but these acute effects necessitated a break in therapy on only five occasions. Concurrent chemotherapy and a relatively short interval between grafting and the initiation of radiation seemed to contribute to more severe radiation reactions. This experience indicates that postoperative adjuvant radiation therapy can be delivered to skin grafted areas without undue fear of complications, especially if the graft is allowed to heal adequately prior to initiating therapy and if chemotherapy is not given in conjunction with radiation

Adsorption of Heavy Metals From Industrial Wastes Using Membranes Prepared by Radiation Grafting

International Nuclear Information System (INIS)

Hegazy, E. A.; Kamal, H.; Maziad, N.; Dessouki, A.M.; Aly, H.F.

1999-01-01

Preparation of synthetic membranes using simultaneous radiation grafting of acrylic acid (AAc) and styrene (Sty) individually and in a binary monomers mixture onto polypropylene (PP) has been carried out. The effect of preparation conditions such as irradiation dose, monomer and inhibitor concentration, comonomer composition on the grafting yield was investigated. The thermal stability and mechanical properties were also investigated as a function of degree of grafting. Accordingly the possibility of its practical use in industrial waste treatment is determined. The prepared cation-exchange membranes possess good mechanical properties, high thermal stability and good characteristics for separation processes. These membranes have also good affinity toward the adsorption or chelation with Fe 3+ , Pb 2+ , and Cd 2+ ions either in a mixture or exists alone in the solution

Modification of macroporous membranes by graft co-polymerization induced by pre-irradiation with an electron accelerator

International Nuclear Information System (INIS)

Grasselli, M.; Yoshii, Fumio

1999-01-01

Glycidyl methacrylate (GMA) and N,N-dimethylacrylamide (DMAA) have been co-grafted on hollow fiber membranes of macroporous polyethylene. Grafted copolymers have been obtained with different ratios of the monomers (molar ratio between 0 and 2 DMAA/GMA). The properties of the modified membranes are studied

A sustained release system using porous cellulose spheres modified by grafting as matrices

International Nuclear Information System (INIS)

Hosoi, Fumio; Makuuchi, Keizo; Saito, Kenji; Koishi, Masumi.

1987-01-01

Polymer-coated spheres, obtained by the graft polymerization of methyl methacrylate (MMA) onto porous spheres based on cellulose by the pre-irradiation method, were used as matrices for the drug sustained release system for salicylic acid. The adsorption of salicylic acid was carried out by dipping the grafted spheres in a 50% aqueous ethanol solution containing salicylic acid. The amount of salicylic acid adsorbed (Q) increased proportionately with the percent graft of MMA (G) to the power of 2.9. Adsorption mechanism of salicylic acid could be expressed in term of Langmuir's adsorption isotherm. The ratio of constants for adsorption and desorption (k) and the saturated amount of salicylic acid adsorbed (Q 0 ) were expressed as k = k 1 G and Q 0 = k 2 G 2.4 , respectively. These results indicate that the number of adsorption sites increased proportionately with the nth power of G as a results of the interaction of grafted poly (methyl methacrylate)(PMMA) and cellulose. Similar results were obtained with grafting of MMA, MMA-styrene (St), and MMA-methacrylic acid (MAc) in the presence of salicylic acid. (author)

Radiosensitivity, mutation and tetraploid induction in the gamma-ray-irradiated growing shoots in mulberry, Morus alba L

International Nuclear Information System (INIS)

Katagiri, Koitsu

1976-01-01

The vigorously developing mulberry shoots on the 1 year old grafted trees of the variety Inchinose were separately exposed to 60 Co γ-ray of 6KR at 120 R/hr and 7.5 KR at 150 R/hr in early July, early August and early September. After the irradiation, all of the irradiated shoots developed axially buds with malformed narrow leaves, and after that, all plants subjected to the irradiation in September and 30% of the July irradiation group and 40% of the August irradiation group both with higher exposure ceased shoot development. This type of radiation damage was large for the plants with higher exposure as compared with those with lower one, and it was also severe for the plants irradiated in July in comparison with those in August. From the ceasing of shoot development the LD 50 value of 150 R/hr irradiation was estimated to be a little more than 7.5 KR. The frequencies of mutation and tetraploid in the grafts produced by the propagation of the axially buds below the leafless portion were high in the grafts with higher exposure than those with lower one, and also the frequencies were high in July irradiation in comparison with August irradiation. It was confirmed that the size of mutation or tetraploid sector was large in the shoots derived from the less advanced axially bud primordia at the time of irradiation than that from the advanced ones. All of tetraploids were the cytochimeras having diploid epidermises over tetraploid internal tissues. (Kobatake, H.)

Bone marrow transplantation in aplastic anaemia using cyclophosphamide and total lymphoid irradiation

International Nuclear Information System (INIS)

Jansen, J.; Zwaan, F.E.; Noordijk, E.M.

1980-01-01

Six patients with severe aplastic anaemia received a bone-marrow graft after conditioning with cyclophosphamide and total lymphoid irradiation (TLI). No rejections occurred. Acute graft-versus-host disease developed in 3 patients and was fatal in one. Another patient died from systemic aspergillus infection. Chronic GVHD of the skin developed in a patient who was grafted with bone marrow from her HLA-phenotypically identical father. These data suggest that conditioning with cyclophosphamide and TLI is a promising regimen. (orig.) [de

Swelling properties of cassava starch grafted with poly (potassium acrylate-co-acrylamide) superabsorbent hydrogel prepared by ionizing radiation

Energy Technology Data Exchange (ETDEWEB)

Barleany, Dhena Ria, E-mail: dbarleany@yahoo.com; Ulfiyani, Fida; Istiqomah, Shafina; Rahmayetty [Department of Chemical Engineering, University of Sultan Ageng Tirtayasa, Cilegon, Banten (Indonesia); Heriyanto, Heri; Erizal [Centre for Application of Isotopes and Radiation, Jakarta (Indonesia)

2015-12-29

Natural and synthetic hydrophylic polymers can be phisically or chemically cross-linked in order to produce hydrogels. Starch based hydrogels grafted with copolymers from acrylic acid or acrylamide have become very popular for water absorbent application. Superabsorbent hydrogels made from Cassava starch grafted with poly (potassium acrylate-co-acrylamide) were prepared by using of ϒ-irradiation method. Various important parameters such as irradiation doses, monomer to Cassava starch ratio and acrylamide content were investigated. The addition of 7,5 % w w{sup −1} acrylamide into the reaction mixture generated a starch graft copolymer with a water absorption in distilled water as high as 460 g g{sup −1} of its dried weight. The effectivity of hydrogel as superabsorbent for aqueous solutions of NaCl and urea was evaluated. The obtained hydrogel showed the maximum absorptions of 317 g g{sup −1} and 523 g g{sup −1} for NaCl and urea solution, respectively (relative to its own dry weight). The structure of the graft copolymer was analyzed by using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM)

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.

Characteristics of histocompatibility barriers in congenis strains of mice. III. Passive enhancement of skin allografts in x-irradiated hosts

International Nuclear Information System (INIS)

Cantrell, J.L.; Kaliss, N.; Hildemann, W.H.

1975-01-01

Passive immunological enhancement of skin allografts was investigated in three donor-host combinations of congenic mice disparate at non-H-2 loci. Serum against the graft donor was derived from mice that had received donor strain lymphoid cells as neonates, and thereby were rendered specifically tolerant of a skin allograft. We refer to this serum as ''allograft-tolerant'' serum. Each strain combination was chosen to provide only two non-H-2 histoincompatibilities present in the donor and absent in the host. The differences are categorized as immunogenetically strong, moderate, or weak, on the basis of skin allograft survival times. With passively administered allograft-tolerant serum, significantly prolonged graft survivals were noted for the weakest combination only. Combined treatment with sublethal x-irradiation and allograft-tolerant serum significantly prolonged graft survival in both the moderate and weak combinations, with the largest effect present in the weakest disparity. A hyperimmune alloantiserum (produced in adults) directed against the graft donor prolonged allograft survival in the strongest disparity when given in combination with irradiation. In this combination, graft survival time was increased in hosts exposed to x-ray alone, but joint treatment with x-ray and the alloantiserum gave the largest increment. In contrast, combined treatment with the serum and an antithymocyte alloantiserum did not affect graft survival times. Treatment with both radiation and antithymocyte serum did not prolong graft survival beyond that in mice given only x-radiation. Immunological enhancement with central inhibition is assumed as the mechanism underlying prolonged graft survival, and it is suggested that a population of thymus-derived killer cells, sensitive to x-irradiation, is required for normal graft rejection. (U.S.)

Immunological aspect of the electron-beam irradiation

Energy Technology Data Exchange (ETDEWEB)

Ikeda, K [Hyogo College of Medicine, Nishinomiya (Japan)

1978-05-01

In the present study, sciatic nerve tissues of the cat were emulsified with the complete Freund's adjuvant and injected into the foot-pads of the guinea pig. Frozen and frozen-irradiated feline sciatic nerve tissues were treated in the similar manner, and their encephalitogenicity was comparatively studied. Affected animals became skinny, weak in the hind limbs and sometimes solid their tails. Antigenic mixtures of the fresh peripheral nerves with adjuvant have sensitized 75% (15 out of 20) of guinea pigs, whereas none of the 41 animals manifested any sign of experimental allergic neuritis (EAN) after intradermal Frozen-preserved peripheral nerve-adjuvant mixtures gave rise to EAN in 29% (6 out of 21) of guinea pigs. The present results appear to show that the electron-beam irradiation might have modified the specific chemical structures of the myelin basic protein to completely suppress the encephalitogenicity of the peripheral nerve-tissues. High-voltage cathode irradiations would be capable of depressing the antigenicity of the transplantation immunology when the antigenic determinants have the chemical structures in common with the encephalitogenic antigens. Excessive amount of the irradiation used to result in severe tissue damages, therefore, an optimum dosis of electron-beams should be determined for each tissue destined for grafting. As the frozen peripheral nerve-adjuvant mixtures have been less encephalitogenic, freezing alone might well be considered partially to improve the acceptability of the grafts. Cryopreservation of the irradiated allografts would be worth further studying.

Immunological aspect of the electron-beam irradiation

International Nuclear Information System (INIS)

Ikeda, Kimiyuki

1978-01-01

In the present study, sciatic nerve tissues of the cat were emulsified with the complete Freund's adjuvant and injected into the foot-pads of the guinea pig. Frozen and frozen-irradiated feline sciatic nerve tissues were treated in the similar manner, and their encephalitogenicity was comparatively studied. Affected animals became skinny, weak in the hind limbs and sometimes solid their tails. Antigenic mixtures of the fresh peripheral nerves with adjuvant have sensitized 75% (15 out of 20) of guinea pigs, whereas none of the 41 animals manifested any sign of experimental allergic neuritis (EAN) after intradermal Frozen-preserved peripheral nerve-adjuvant mixtures gave rise to EAN in 29% (6 out of 21) of guinea pigs. The present results appear to show that the electron-beam irradiation might have modified the specific chemical structures of the myelin basic protein to completely suppress the encephalitogenicity of the peripheral nerve-tissues. High-voltage cathode irradiations would be capable of depressing the antigenicity of the transplantation immunology when the antigenic determinants have the chemical structures in common with the encephalitogenic antigens. Excessive amount of the irradiation used to result in severe tissue damages, therefore, an optimum dosis of electron-beams should be determined for each tissue destined for grafting. As the frozen peripheral nerve-adjuvant mixtures have been less encephalitogenic, freezing alone might well be considered partially to improve the acceptability of the grafts. Cryopreservation of the irradiated allografts would be worth further studying. (author)

Use of gamma and UV radiation in grafting hydrogel polymers to membranes

International Nuclear Information System (INIS)

Baker, L.; Hill, D.J.T.; Whittaker, A.; Hunter, D.; Davis, T.P.

1998-01-01

Full text: Dimethylacrylamide and N-isopropylacrylamide hydrogels are useful for their ability to absorb large amounts of water and for their thermotropic response. However as membranes they do not have the mechanical properties to be applicable in industry. Therefore these hydrogels have been grafted to polyvinylidinedifluoride (PVDF) membranes using radiation. Both UV and gamma irradiation were used. In the first method the PVDF membranes were first hydroxylated by immersion in a aqueous solution of potassium peroxydisulfate (10% w/v), with nitrogen purging for two hours at 80 deg C. This was followed by immersion in an aqueous solution of riboflavine (4mg/L) and monomer (10% v/v), degassing with nitrogen and irradiation under a Mercury UV light (wavelength 240 nm) at room temperature for 15 minutes. Membranes were washed by soxhlet extraction in distilled water and oven dried. The second method of grafting hydrogels to membranes involved immersing the membrane in 10 mL of distilled water containing monomer and CuSO 4 to prevent homopolymerisation. The solution was degassed with N 2 for 3 minutes then irradiated under nitrogen using a 60 Co source for various time periods. The effect of varying monomer and CuSO 4 concentration as well as dose rate and dose were studied. Membranes were rinsed in distilled water for 24 hours and dried in an oven before characterisation. Grafting was characterised by mass change (Mettler AC 100 balance), XPS (PHI Model 560 XPS/SAM/SIMA1 multitechnique surface analysis system), SEM (Hitachi S-900 Field Emission SEM) and FTIR-ATR (Perkn Elmer System 2000 FTIR with MIRMCT detector)

Electron-beam-induced post-grafting polymerization of acrylic acid onto the surface of Kevlar fibers

Science.gov (United States)

Xu, Lu; Hu, Jiangtao; Ma, Hongjuan; Wu, Guozhong

2018-04-01

The surface of Kevlar fibers was successfully modified by electron beam (EB)-induced post-grafting of acrylic acid (AA). The generation of radicals in the fibers was confirmed by electron spin resonance (ESR) measurements, and the concentration of radicals was shown to increase as the absorbed dose increased, but decrease with increasing temperature. The influence of the synthesis conditions on the degree of grafting was also investigated. The surface microstructure and chemical composition of the modified Kevlar fibers were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The SEM images revealed that the surface of the grafted fibers was rougher than those of the pristine and irradiated fibers. XPS analysis confirmed an increase in C(O)OH groups on the surface of the Kevlar fibers, suggesting successful grafting of AA. These results indicate that EB-induced post-grafting polymerization is effective for modifying the surface properties of Kevlar fibers.

Aortic Graft Infection Secondary to Iatrogenic Transcolonic Graft Malposition.