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Selective laser vaporization of polypropylene sutures and mesh  

Science.gov (United States)

Complications from polypropylene mesh after surgery for female stress urinary incontinence (SUI) may require tedious surgical revision and removal of mesh materials with risk of damage to healthy adjacent tissue. This study explores selective laser vaporization of polypropylene suture/mesh materials commonly used in SUI. A compact, 7 Watt, 647-nm, red diode laser was operated with a radiant exposure of 81 J/cm2, pulse duration of 100 ms, and 1.0-mm-diameter laser spot. The 647-nm wavelength was selected because its absorption by water, hemoglobin, and other major tissue chromophores is low, while polypropylene absorption is high. Laser vaporization of ~200-?m-diameter polypropylene suture/mesh strands, in contact with fresh urinary tissue samples, ex vivo, was performed. Non-contact temperature mapping of the suture/mesh samples with a thermal camera was also conducted. Photoselective vaporization of polypropylene suture and mesh using a single laser pulse was achieved with peak temperatures of 180 and 232 °C, respectively. In control (safety) studies, direct laser irradiation of tissue alone resulted in only a 1 °C temperature increase. Selective laser vaporization of polypropylene suture/mesh materials is feasible without significant thermal damage to tissue. This technique may be useful for SUI procedures requiring surgical revision.

Burks, David; Rosenbury, Sarah B.; Kennelly, Michael J.; Fried, Nathaniel M.

2012-02-01

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Polypropylene Suture Versus Skin Staples for Securing Mesh in Lichtenstein Inguinal Hernioplasty  

International Nuclear Information System (INIS)

Objective: To compare polypropylene suture and skin staples for securing mesh in Lichtenstein inguinal hernioplasty in terms of mean operating time and postoperative pain. Study Design: Randomized clinical trial. Place and Duration of Study: Surgical Ward, Combined Military Hospital, Kharian, from August 2011 to February 2012. Methodology: All individuals fulfilling inclusion criteria underwent elective Lichtenstein inguinal hernioplasty as admitted patients, under spinal anaesthesia and with aseptic measures. In group 1, during the operation, mesh fixation was done with 2/0 polypropylene suture and skin was closed with subcuticular 2/0 polypropylene suture whereas in group 2, the anchorage of mesh was done with skin staples and skin was closed with staples from the same stapler. Mean operative time and postoperative pain, assessed on a visual analog score, were compared between the groups. Results: The overall postoperative pain was lower (p = 0.026) when staples were used to anchor mesh. Moreover, operative time was also lower (37.42 A +- 2.69 minutes) in staple group versus (42.44 A +- 2.55 minutes in polypropylene group). Conclusion: Mean operating time and postoperative pain is less in securing mesh with skin staples as compared to polypropylene suture in Lichtenstein inguinal hernioplasty. (author)

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Polypropylene  

International Nuclear Information System (INIS)

This book gives description of polypropylene with history, polypropylene chemistry such as polymerization reaction and manufacture method of polypropylene, structure and property of polypropylene like molecular weight, melt flow index and property of inter polymer, property of polypropylene the position of polypropylene among plastic and functional property of polypropylene, ageing resistance of polypropylene, processing of polypropylene like injection molding film and type use of polypropylene with using cases.

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Managing common suturing problems.  

Science.gov (United States)

The closure of surgical wounds can be improved by applying some basic techniques for suturing and for correcting suture errors. These techniques include 1) the locking stitch, 2) the pulley stitch for closing large gaping defects, and 3) a means of welding polyfilament synthetic polyamide suture and polypropylene suture. PMID:2040754

Snow, S N; Dortzbach, R; Moyer, D

1991-06-01

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A Prospective Randomized Study Comparing Skin Staples and Polypropylene Sutures for Securing the Mesh in Lichtenstein's Repair  

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Results: Mesh fixation with skin staples is as effective as conventional sutures with the added advantage of significant reduction in the operating time and complications. Conclusions: The staples can be applied much more quickly than sutures for fixing the mesh, thus saving the operating time. The infection rate is significantly decreased with staples. The staples are not associated with any significant complications or recurrence. [Arch Clin Exp Surg 2014; 3(3.000: 147-152

Pankaj Shivhare

2014-06-01

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Gross and Histologic Evaluation of Abdominal Adhesions Associated with Chromic Catgut and Polypropylene Sutured Enteropexies in Dog Evaluación Macroscópica e Histológica de las Adherencias Abdominales Asociadas a Enteropexias Suturadas con Catgut Crómico y Polipropileno en Perros  

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Full Text Available The gross and histologic patterns of abdominal adhesions formed by the use of chromic catgut and polypropylene suture materials were evaluated in dogs. Gross and histologic examinations did not reveal significant difference (p>0.05 in the degree of adhesions observed at enteropexy sites in both suture materials. The use of polypropylene with superior suture qualities should be considered instead of chromic catgut for procedures in which adhesion is desired in the dog.Fueron evaluados los patrones macroscópicos e histológicos de las adherencias abdominales formadas por el uso de catgut crómico y materiales de sutura de polipropileno. Los exámenes macroscópicos e histológicos no revelaron diferencias significativas (p> 0,05 en el grado de adherencias observadas en los sitios de la enteropexia en ambos materiales de sutura. El uso de suturas de polipropileno con mejores cualidades debe ser considerado en lugar del catgut cromado para procedimientos en los que la adherencia en el perro es deseada.

J. F Akinrinmade

2010-12-01

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Comparação entre o uso de fio inabsorvível (polipropileno) e fio absorvível (poliglactina 910) na fixação de prótese de polipropileno em correção de defeitos músculo-aponeurótico da parede abdominal: estudo experimental em ratos / Comparison between fixation of polypropylene mesh with polypropylene suture and polyglactin 910 suture for treatment of muscle-aponeurotic defects of abdominal wall: experimental study in rats  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese OBJETIVO: Comparar a fixação da tela de prolipropileno na correção de defeitos músculo-aponeuróticos da parede abdominal com fio absorvível (poliglactina 910) e fio inabsorvível (polipropileno). MÉTODOS: Oitenta e um ratos machos da linhagem Wistar foram submetidos a ressecção longitudinal de um seg [...] mento músculo-aponeurótico e peritoneal (3x2 cm) da parede abdominal, seguida por reforço com tela de polipropileno, em forma de ponte sobre a aponeurose. Foram distribuídos em dois grupos de acordo com o fio usado para fixação da tela: grupo poliglactina 910 - fixada com 8 pontos separados e eqüidistantes em forma de "U" com fio 4-0; e grupo polipropileno - fixada com fio 4-0. A pele foi suturada com fio de nylon 4-0. Após 90 dias, os animais foram submetidos à eutanásia e avaliados macroscopicamente, quanto à presença de hérnia e avaliação histológica da reação inflamatória crônica, absorção do fio e percentagem de fibrose pela técnica vídeo-morfométrica assistida por computador. Utilizaram-se as técnicas de coloração de hematoxilina-eosina e picrossírius. RESULTADOS: Não houve diferença estatisticamente significante entre os grupos, quanto à presença de hérnia incisional (p=0,194). Houve maior fibrose no grupo polipropileno pela avaliação histológica de reação inflamatória crônica, o que não foi verificado quando avaliado pela técnica vídeo-morfométrica (p=0,0005). Não houve diferença entre os grupos quando avaliados os gigantócitos, linfócitos e neutrófilos. Houve maior número de macrófagos no grupo polipropileno (p=0,02). Não houve absorção do fio poliglactina 910 após 90 dias. CONCLUSÃO: A fixação de tela de polipropileno pode ser feita com êxito com fios absorvíveis como a poliglactina 910. Abstract in english PURPOSE: The aim of this study is to assess fixation of a polypropylene mesh in the repair of incisional hernias comparing an absorbable (polyglactin 910) suture and an inabsorbable (polypropylene) one. METHODS: Eighty-one male rats of the Wistar breed, weighing from 180g to 220g, were submitted to [...] a longitudinally resection of a musculoaponeurotic and peritoneal segment (3x2 cm) of the abdominal wall. Reconstruction was performed by reinforcement with polypropylene mesh, overlaid on the aponeurosis. They were distributed in two groups according to the thread used for mesh fixation as follows: (1) polyglactin 910 group, fixed with 8 stitches 4.0 Polyglactin 910 suture; and (2) Polipropylene group, fixed with 4.0 polypropylene suture. The skin suture was performed with 4.0 nylon continuous stitches. After 90 days, animals were sacrificed and submitted to macroscopic evaluation for the presence of hernias. Histologic samples were stained for Hematoxylin-Eosine and Sirius-Red and were assessed for signs of cicatrization such as chronic inflammatory reaction, fibrosis, suture absortion and percentage of fibrosis by computer-assisted video morfometric technic. RESULTS: There was no significant difference between the groups studied in relation to hernia formation (p=0,194). The histologic study showed significant increase of fibrotic reaction in the polipropylene group (p=0,0005), but this finding was not confirmed in the video-morfometric evaluation. Considering chronic inflammatory reaction, there was no difference between groups in relation to giant cells, lymphocytes and neutrophils. However, in the polipropylene group, macrophages were significantly increased (p=0,02). Polyglactin 910 has not been absorved 90 days after the procedure. CONCLUSIONS: The results of this study suggest that the fixation of polipropilene mesh is effective using absorbable sutures in the repair of ventral (incisional) hernias.

Álvaro, Gianlupi; Manoel Roberto Maciel, Trindade.

2004-04-01

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Sutura arterial com técnicas contínua e de pontos separados, utilizando-se os fios polipropilene e polidioxanone: estudo experimental em coelhos Arterial suture with continuous and interrupted techniques, using polypropylene and polydioxanone threads: experimental study in rabbits  

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Full Text Available OBJETIVO: Observar o comportamento da sutura arterial em aortas abdominais de coelhos em crescimento, comparando-se as técnicas contínua e com pontos separados, empregando-se dois tipos de fios: Polipropilene 7-0 (inabsorvível e Polidioxanone 7-0 (absorvível. MÉTODOS: Grupos: GI - Controle (sem sutura; GII - Polipropilene, Pontos Separados; GIII - Polipropilene, Contínua; GIV - Polidioxanone, Pontos Separados e GV - Polidioxanone, Contínua. Cada grupo foi subdividido em quatro Momentos de Eutanásia: aos 7, 14, 30 e 60 dias de pós-operatório. Foram avaliados: peso dos animais, diâmetros e pulsos arteriais, estenose, trombose, aderências, aortografia, visibilidade do fio, cicatrização e microscopia. RESULTADOS: a após 60 dias, o local da linha de sutura cresceu de forma significativa em todos os grupos; b a técnica de sutura com pontos separados causou menor estenose da linha de sutura, observada tanto no ato cirúrgico, como na eutanásia dos animais; c no exame histopatológico, as diferenças encontradas entre grupos foram transitórias, não persistindo após 60 dias de pós-operatório. CONCLUSÃO: O polidioxanone mostrou ser a melhor opção, entre os dois fios, para sutura de artérias em crescimento, pois causa pouca ou nenhuma restrição ao crescimento arterial na linha de sutura, mesmo quando se emprega a técnica contínua.PURPOSE: To assess the arterial suture, comparing continuous and interrupted techniques, in abdominal aorta of growing rabbbits, using two types of suture material: Polypropylene 7-0 (nonabsorbable and Polydioxanone 7-0 (absorbable. METHODS: Groups: GI - Control, without arterial suture; GII - Polypropylene, Interrupted technique; GIII - Polipropilene, Continuous technique; GIV - Polydioxanone, Interrupted technique and GV - Polydioxanone, Continuous technique. Each group was subdivided in four Moments of Euthanasia , according with the number of days after surgery: 7 , 14 , 30 and 60 days. The following itens were assessed: weight, arterial diameters and pulse, stenosis, thrombosis, tissue adherence at the suture line, aortography, suture material visibility, suture line healling visibility and microscopic study. RESULTS: a after 60 days, the suture line site had a significant growing in all groups; b interrupted technique result less suture line stenosis in surgical act and in euthanasia c the difference between groups showed in the microscopic study, was transitory, not pesisting after 60 days post surgery; CONCLUSION: Polydioxanone is better than polypropylene for suture in growing artery, not causing (or causing little restriction to the growing of the suture line, even though using continuous technique.

Nelson Leonardo Kerdahi Leite de Campos

2003-10-01

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Comparison of scar with polypropylene and polyglactin 910 in thyroid incisions  

International Nuclear Information System (INIS)

To compare quality of scar after subcuticular stitches between Polypropylene (Prolene), a non-absorbable suture, with Polyglactin 910 (Vicryl), an absorbable suture after thyroid surgery. Study Design: Randomized controlled trail (RCT). Place and Duration of Study: Department of Surgery Combined Military Hospital and Military Hospital Rawalpindi from 1 Jan 2007 to 31 Dec 2007. Material and Methods: Sixty patients undergoing elective thyroid surgery were included and randomly divided into two groups using random number tables. Informed written consent was obtained from each patient. The neck wound was closed by subcuticular suturing technique and the suture material was used according to the sampling technique. The patients were followed up in OPD on tenth post operative day and twelve weeks after surgery for the quality of scar. Results: After 10 days, 1 patient in each of the Polypropylene group (3.3%) and Polyglactin 910 group (3.3%) had a bad scar (p = 1.000). After twelve weeks of surgery, 2 patients in the Polypropylene group (6.7%) and 3 patients in the Polyglactin 910 group (10.0%) had bad scars (p = 1.000). Conclusion: There is no significant difference between the frequency of bad scar formation in the Polypropylene and Polyglactin 910 group. It is thus recommended that absorbable Polyglactin 910 sutures should be used for wound closure after thyroid surgery as it does not require suture removal and thus prevents patient anxiety and discomfort and also saves ent anxiety and discomfort and also saves surgeon and staff's time. (author)

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Gross and Histologic Evaluation of Abdominal Adhesions Associated with Chromic Catgut and Polypropylene Sutured Enteropexies in Dog / Evaluación Macroscópica e Histológica de las Adherencias Abdominales Asociadas a Enteropexias Suturadas con Catgut Crómico y Polipropileno en Perros  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish Fueron evaluados los patrones macroscópicos e histológicos de las adherencias abdominales formadas por el uso de catgut crómico y materiales de sutura de polipropileno. Los exámenes macroscópicos e histológicos no revelaron diferencias significativas (p> 0,05) en el grado de adherencias observadas e [...] n los sitios de la enteropexia en ambos materiales de sutura. El uso de suturas de polipropileno con mejores cualidades debe ser considerado en lugar del catgut cromado para procedimientos en los que la adherencia en el perro es deseada. Abstract in english The gross and histologic patterns of abdominal adhesions formed by the use of chromic catgut and polypropylene suture materials were evaluated in dogs. Gross and histologic examinations did not reveal significant difference (p>0.05) in the degree of adhesions observed at enteropexy sites in both sut [...] ure materials. The use of polypropylene with superior suture qualities should be considered instead of chromic catgut for procedures in which adhesion is desired in the dog.

J. F, Akinrinmade; A. O, Lawal.

1221-12-01

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Electron beam sterilization surgical sutures, 2  

International Nuclear Information System (INIS)

Possibility of electron beam (1.5 MeV, Van de Graaff accelerator) sterilization of a polypropylene surgical suture was examined from the points of sterilization effect and material degradation by the reason of that ? ray sterilization has not been permitted of its high degree of degradation. The D values of B. pumilus ATCC 27142 dry spores were determined to be 0.11 x 104 Gy in air and 0.18 x 104 Gy under the nitrogen stream irradiation, and the sterilization doses for electron beam were calculated to be 1.6 x 104 Gy in air and 2.7 x 104 Gy under the nitrogen stream, corresponding to ? ray sterilization assurance level of 2.5 x 104 Gy. Tensile strength of the polypropylene suture was 95 % of original strength soon after electron beam irradiation in air and was changed to be 81 % after 6 months storage, this is within the limit of the recommended value of 80 %. Furthermore, heat treatment (85 deg C, 1 hr.) following irradiation reduced degradation of irradiated polypropylene: its tensile strength was 93 % soon after irradiation but 97 % after 6 months. In the case of irradiation under the nitrogen stream, tensile strength after 6 months storage was 73 % without heat treatment, but 93 % with heat treatment. Based on the above results, we concluded that electron beam sterilization is applicable to the polypropylene surgical suture used in this experiment and heat treatment successive irradiation is effective to resccessive irradiation is effective to restrain material degradation. (author)

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Urolithiasis on absorbable and non-absorbable suture materials in the rabbit bladder.  

Science.gov (United States)

Absorbable and non-absorbable suture materials were evaluated for calculi formation and tissue reactivity in the rabbit bladder. Five-O chromic, polydioxinone and polypropylene sutures were used to close cystostomies made in New Zealand white rabbits. Bladders were evaluated at 15, 30, 60 and 90 days. Calculi formed on all sutures tested and the persistence of calculi appeared to be dependent on the longevity of the suture material used. This data suggests that the use of non-absorbable suture material in urologic surgery may contribute to calculus formation. PMID:3080609

Morris, M C; Baquero, A; Redovan, E; Mahoney, E; Bannett, A D

1986-03-01

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Quantitative evaluation of stiffness of commercial suture materials.  

Science.gov (United States)

The bending stiffness of 22 commercial suture materials of varying size, chemical structure and physical form was quantitatively evaluated using a stiffness tester (Taber V-5, model 150B, Teledyne). The commercial sutures were Chromic catgut; Dexon (polyglycolic acid); Vicryl (polyglactin 910); PDS (polydioxanone); Maxon (polyglycolide-trimethylene carbonate); Silk (coated with silicone); Mersilene (polyester fiber); Tycron (polyester fiber); Ethibond (polyethylene terephthalate coated with polybutylene); Nurolon (nylon 66); Surgilon (nylon 66 coated with silicone); Ethilon (coated nylon 66), Prolene (polypropylene); Dermalene (polyethylene), and Gore-tex (polytetraflouroethylene). These are both natural and synthetic, absorbable and nonabsorbable and monofilament and multifilament sutures. All of these sutures were size 2-0, but Prolene sutures with sizes ranging from 1-0 to 9-0 were also tested to determine the effect of suture size on stiffness. The bending stiffness data obtained showed that a wide range of bending stiffness was observed among the 22 commercial sutures. The most flexible 2-0 suture was Gore-tex, followed by Dexon, Silk, Surgilon, Vicryl (uncoated), Tycron, Nurolon, Mersilene, Ethibond, Maxon, PDS, Ethilon, Prolene, Chromic catgut, coated Vicryl, and lastly, Dermalene. The large porous volume inherent in Gore-tex monofilament suture was the reason for its lowest flexural stiffness. Sutures with a braided structure were generally more flexible than those of a monofilament structure, irrespective of the chemical constituents. Coated sutures had significantly higher stiffness than the corresponding uncoated ones. This is particularly true when polymers rather than wax were used as the coating material. This increase in stiffness is attributable to the loss of mobility under bending force in the fibers and yarns that make up the sutures. An increase in the size of the suture significantly increased the stiffness, and the magnitude of increase depended on the chemical constituent of the suture. The flexural stiffness of sutures was also found to depend on the duration of bending in the test for stiffness. In general, monofilament sutures exhibited the largest time-dependent stiffness. This was most pronounced with the Gore-tex suture. Most braided sutures also showed less time-dependence in stiffness. Nylon sutures did not exhibit this time-dependent phenomenon regardless of physical form. PMID:2919353

Chu, C C; Kizil, Z

1989-03-01

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New-Fangled Slowly-Absorbable versus Non-Absorbable Sutures for Abdominal Fascial Closure. Have the Goals towards an Advantageous Suture Been Met?  

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Full Text Available Background-Aim: The technique of abdominal closure along with the material to be used is constantly evolving. The aim of the present study is to evaluate differences in midline laparotomy closure with a standard closure technique and new-fangled slow-absorbable versus non-absorbable sutures. Material and Methods: A prospective, comparative study of patients undergoing laparotomy closure with either STARDIOX (Polydioxanone or STARLENE (Polypropylene sutures during a 9 month period was performed. Patients were evaluated and compared in terms of surgical site infection, incisional hernia, burst abdomen, and suture sinus formation. Results: A total of 284 patients were included [141 in the STARDIOX (Polydioxanone group and 143 in the STARLENE (Polypropylene group]. Sinus formation was not noticed and no palpable knots were reported in both groups. Moreover burst abdomen was never encountered. Incisional hernia rates were similar for both suture materials: n = 6 (4.3% for the STARDIOX (Polydioxanone group and n = 5 (3.5% for the STARLENE (Polypropylene group. There was not statistically significant relationship between the type of suture that was used and wound infection: n = 5 (3.5% in the STARDIOX (Polydioxanone group and n = 6 (4.2% in the STARLENE (Polypropylene group. Complications did not occur in 96.1% of all patients. Conclusions: Our study suggests that there are no significant differences between these two new-fangled sutures. It seems that progress of suture materials has led to a step towards the goals of a beneficial suture and from then on complications of surgical wound closure should be merely a matter of operative technique.

Georgios Anthimidis

2013-05-01

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Looped suture properties: implications for multistranded flexor tendon repair.  

Science.gov (United States)

Multiple-strand repair techniques are commonly used to repair cut flexor tendons to achieve initial biomechanical strength. Looped sutures achieve multiple strands with fewer passes and less technical complexity. Their biomechanical performance in comparison with an equivalent repair using a single-stranded suture is uncertain. This study examined the mechanical properties of double-stranded loops of 3-0 and 4-0 braided polyester (Ticron) and polypropylene monofilament (Prolene). Double loops were generally less than twice the strength of a single loop. Ticron and Prolene had the same strengths, but Ticron was stiffer. The 4-0 double loops had significantly higher stiffness than 3-0 single loops. Increasing the size of sutures had a larger relative effect on strength than using a double-stranded suture. However, a double-strand loop had a larger effect on increasing stiffness than using a single suture of a larger equivalent size. Looped suture repairs should be compared with standard techniques using a thicker single suture. PMID:25698798

Haddad, R; Peltz, T; Bertollo, N; Walsh, W R; Nicklin, S

2015-03-01

16

A comparison of ultrasonic suture welding and traditional knot tying.  

Science.gov (United States)

The slippage of knots and the technical challenge of tying them securely are potential impediments to certain arthroscopic procedures. Ultrasonic energy delivered at 70 kHz can be used to weld No. 2 polypropylene suture. This method was compared with a traditional knot (surgeon's knot with four alternating half hitches) tied with an open technique to determine whether welding of sutures is comparable, in mechanical properties, to hand-tied knots. Both loops were fashioned around a 0.25-inch mandrel and then tested. The load to reach 3-mm elongation (point of likely biologic failure of a repair) was significantly greater for welded sutures than for knots. The elongation at ultimate failure was significantly less for welded sutures than for knots. The number of cycles to failure and the creep after initial displacement were similar for both welded and knotted suture loops. The ultimate load to failure was significantly greater for the knotted than for the welded suture. The welding of suture for the repair of musculoskeletal soft tissue presents an attractive alternative to traditional knot tying, particularly for arthroscopic applications. PMID:11394598

Richmond, J C

2001-01-01

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Comparison of laser-welded and sutured arteriotomies.  

Science.gov (United States)

We compared the histologic features, tensile strength, and collagen synthesis of laser-welded and sutured arteriotomies. Four bilateral canine femoral or carotid arteries, 2 cm long, were studied at one through four weeks postoperatively, with one vessel (control) closed with interrupted 6-0 polypropylene sutures and the contralateral vessel (experimental) welded with an argon laser (0.5 W [1417 J/cm2], four-minute exposure per 1-cm length of incision). Histologic examination revealed that laser-welded arteriotomies had less inflammatory reaction, more normal collagen and elastin reorientation, and similar endothelial continuity when compared with the control, sutured wounds. The tensile strength of the one- and two-week laser-welded specimens was less than that of sutured wounds and became approximately equal to sutured repairs at three and four weeks. There were no significant differences in the rate of collagen synthesis. There was no evidence of abnormal healing in the laser-welded specimens, suggesting that argon laser welding may be an alternative to suture repair of arteriotomies. PMID:3533008

White, R A; Kopchok, G; Donayre, C; Abergel, R P; Lyons, R; Klein, S R; Dwyer, R M; Uitto, J

1986-10-01

18

Cyclic testing of meniscal sutures.  

Science.gov (United States)

Suturing the meniscus has become a standard procedure for repairable tears. Studies investigating the outcome of meniscal sutures report a considerable rate of failures. Regarding the indications, which have been extended to the avascular zones, and regarding some accelerated rehabilitation protocols, the need for further in vitro investigations has become obvious. The aim of this study was to compare different meniscal suture types (vertical and horizontal mattress sutures) and materials (absorbable monofilament PDS 2-0, and nonabsorbable braided Ethibond 2-0 [Ethicon, Somerville, NJ]) under standard and cyclic loading conditions. Testing was performed on medial porcine menisci. In group A, specimens were tested to failure at a cross-head speed of 50 mm/minute. In group B, cyclic testing (100 cycles) was performed first within different load intervals (5 to 20 N and 5 to 40 N). Finally, the specimens were loaded until failure. In both groups, the failure loads were recorded and the failure modes were analyzed. In group A, there was no difference between suture type or suture material, with a mean failure load of 60 N. The failure modes were significantly different for vertical (100% suture failure) and horizontal sutures (50% suture failure) (P sutures failed under cyclic loading (7 with 40-N load, 1 with 20-N load). The gap of the sutured tear that appeared within the first load cycles was broader in horizontal sutures (P suture material. The ultimate failure loads after cyclic loading did not differ from the values of group A. These results show that meniscal sutures may fail under repetitive loading conditions and that a gap appears between the meniscal margins within the first loading cycles irrespective of the suture type and suture material used. The appearance of the gap and suture disappearance on the meniscal surface because of partial tissue failures (which were more pronounced in the horizontal sutures) confirmed the superior resistance of meniscal tissue to vertical sutures. PMID:10882446

Seil, R; Rupp, S; Kohn, D M

2000-01-01

19

Experimental Studies on Mortar Using Polypropylene Fibers  

OpenAIRE

An experimental program was carried out to evaluate the properties of cement Mortar. Compressive strength test, splitting tensile strength test and the water absorption test were performed and the results were analysed statistically. Polypropylene fibers can greatly increase the properties of cement Mortar. Specimens containing fiber of 0.00%, 0.10%, 0.20% and 0.30% are prepared and tested in this work. It is demonstrated that a certain amount of fibers enhances the compressiv...

Paradava, Divyeshkumar D.; Prof. Jayeshkumar Pitroda2

2014-01-01

20

Short- and long-term biomechanical and morphological study of new suture types in abdominal wall closure.  

Science.gov (United States)

To perform an abdominal-wall closure, a continuous suture is the preferred method. The suture materials that are most commonly employed in abdominal surgery are polypropylene and polydioxanone. However, in recent times, new products have been marketed, such as non-absorbable polyurethane with elastic properties (Assuplus(®), Assut Europe, Italy) and absorbable barbed polydioxanone (Filbloc(®), Assut Europe, Italy). The purpose of this study was to compare the ability of those against the standard polypropylene (Surgipro(TM), Covidien, USA) and polydioxanone (Assufil(®), Assut Europe, Italy) to mimic the biomechanical behavior of the abdominal wall closure. Comparison of the sutures was made first with the materials alone and later in a laparotomy closure of a rabbit abdomen, used as an animal model. The biomechanical analysis consisted of uniaxial tensile tests of threads and sutured samples of the animal abdomen. In the latter case, results were analyzed at short- (21days) and long- (180days) term intervals after the surgery. The morphology studies and collagen expression of the samples were also investigated. The results determined that polydioxanone and polypropylene sutures showed a linear elastic behavior, with barbed polydioxanone as the most compliant suture and polyurethane as the stiffest. The sutured samples showed a statistically significant loss of resistance, measured as the load needed to perform a certain stretch, when compared with the corresponding control tissue. Analysis of the stress-stretch curves showed that elastic polyurethane was the only suture able to reproduce the mechanical behavior of healthy tissue in the short term, while the rest of the sutures remained less stiff. This coincides with the expression of type I collagen observed in this group at this point in the study. In the long term, there was no difference among the sutures, and none was able to mimic control behavior. PMID:24859461

Simón-Allué, R; Pérez-López, P; Sotomayor, S; Peña, E; Pascual, G; Bellón, J M; Calvo, B

2014-09-01

21

Selective suture cutting for control of astigmatism following cataract surgery  

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Full Text Available Use of 10-0 monofilament nylon in ECCE cataract surgery leads to high with the rule astigmatism. Many intraoperative and post operative methods have been used to minimise post operative astigmatism. We did selective suture cutting in 38 consecutive patients. Mean keratometric astigmatism at three and six weeks post operative was 5.76 and 5.42 dioptres (D respectively. 77.5% of eyes had astigmatism above 2 D. Selective suture cutting along the axis of the plus high cylinder was done after six weeks of surgery. Mean post suture cutting keratometric astigmatism was 3.3 D and 70% of the eyes had astigmatism below 2 D. After 3 months of surgery mean keratometric astigmatism was reduced to 1.84 D. Axis of the astigmatism also changed following suture cutting. 40% of the eyes showed improvement in their Snellen acuity following reduction in the cylindrical power.

Bansal R

1992-01-01

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Mechanical comparison of 10 suture materials before and after in vivo incubation.  

Science.gov (United States)

The material properties of ten 2-O suture materials were evaluated tensiometrically at time = 0 and again after 6 weeks incubation in rats. All suture material was incubated and tested without knots. Specialized machinery was used with a custom securing apparatus to pull suture material apart at constant speed. Stress-strain curves were derived, and from these strength, toughness, strain at rupture, and elastic modulus were determined. Sutures tested included Vicryl [poly(glycolide-lactide)], Dexon (polyglycolic acid), Ethibond (polyester), silk, plain gut, chromic gut, Maxon (polyglyconate), PDS (polydioxanone), nylon, and Prolene (polypropylene). Elastic modulus was greatest for braided, least for monofilament, and intermediate for gut sutures, regardless of chemical composition (ANOVA, P = 0.0001). Strength, strain, and toughness decreased in all of the sutures over time in vivo with the exception of braided polyester (Ethibond), which remained stable. Silk demonstrated the least strength and toughness while PDS and Maxon were the strongest and toughest at time = 0. Vicryl, Dexon, and gut sutures were absorbed to the point that they could not be tested after 6 weeks in vivo. Performance tables are provided for all sutures. PMID:8152233

Greenwald, D; Shumway, S; Albear, P; Gottlieb, L

1994-04-01

23

Releasable suture technique for trabeculectomy  

Directory of Open Access Journals (Sweden)

Full Text Available We studied the effect of the releasable suture technique on immediate postoperative intraocular pressure (IOP. Nine eyes of nine patients with glaucoma had trabeculectomy with a releasable suture. In the six eyes that did not receive antimitotics, the suture was released by the fifth postoperative day; in the others suture release was delayed up to the fourteenth day. Of the nine patients, one had an acceptable postoperative IOP and did not need suture release; in another the suture broke and could not be released. In the remaining seven patients, the difference between the pre-release and post-release IOP was statistically significant (p < 0.001. The complications of this technique include failed suture release, subconjunctival hematoma and a distinctive "windshield wiper" keratopathy.

Jacob Pushpa

1993-01-01

24

Radiation treatment of polypropylene  

International Nuclear Information System (INIS)

Structural changes in polypropylene resulting from high energy electron beam irradiation have been examined. Polymer irradiated in a nitrogen atmosphere is characterized as containing long chain branch structures. A branching index, defined as the ratio of intrinsic viscosity of irradiated polymer to the intrinsic viscosity of linear polymer of equivalent molecular weight, is used to quantify the extent of branching. Polymer crystallization and solution properties undergo significant changes as a result of radiation treatment. Treated polypropylene is highly nucleated. Nucleation density is several orders of magnitude greater than linear polypropylene. Temperature rising elution fractionation (TREF) indicates that the long-chain branched structure contributes to increasing the solubility of polypropylene without greatly reducing the crystallizability and melting point of the solubilized fractions. The presence of long chain branching has a pronounced effect on the polymers extensional rheology in the molten state. Radiation treated polymer exhibits strain hardening elongational viscosity

25

Comparative study of trabeculectomy using single sutures versus releasable sutures  

Science.gov (United States)

Background The purpose of this study was to compare the outcomes of trabeculectomy using single sutures or releasable sutures. Methods This retrospective study analyzed the medical records of 61 patients who had undergone trabeculectomy using single sutures (n = 33, 54.1%) or releasable sutures (n = 28, 45.9%). The scleral flap was secured with a mean 3.9 (range 3–5) single sutures in 33 patients and with three releasable sutures in 28 patients. Primary outcomes were the success rate, based on intraocular pressure and medication usage, and the frequency of complications and post-surgical interventions. The criteria used to determine complete success were, first, intraocular pressure < 18 mmHg and, second, ?21 mmHg and ?20% intraocular pressure reduction without glaucoma medication. Results All patients had an intraocular pressure ? 21 mmHg; 87.5% in the single suture group and 92.6% in the releasable suture group had an intraocular pressure < 18 mmHg at 24 months. There was a highly significant reduction in intraocular pressure to baseline values in both groups at the last visit. Applying the first criterion, complete success was achieved in 57.6% of patients with single sutures and 71.4% with releasable sutures, and based on the second criterion, 66.7% and 71.4%, respectively. No significant difference was found between the groups with regard to intraocular pressure, or success or complication rates. Conclusion The results of trabeculectomy using single sutures or releasable sutures are equivalent. Therefore, the choice of suture technique should be based on individual patient requirements and surgeon experience. PMID:22848142

Matlach, Juliane; Hoffmann, Niels; Freiberg, Florentina J; Grehn, Franz; Klink, Thomas

2012-01-01

26

Radiation crosslinking of polypropylene  

International Nuclear Information System (INIS)

The radiation crosslinking of polypropylene with several kinds of polyfunctional monomers has been examined, and it has been clarified that the enhanced crosslinking may be classified into two types. In particular, the irradiation crosslinking process of polypropylene containing a polyfunctional monomer having an acryloyloxy group giving a specific gel - dose curve has been studied by infrared absorption spectrum and oxygen absorptivity measurement in comparison with the non-enhanced system. (author)

27

Radiation crosslinking of polypropylene  

International Nuclear Information System (INIS)

The radiation crosslinking of polypropylene with several kinds of polyfunctional monomers has been examined, and it has been clarified that the enhanced crosslinking may be classified into two types. In particular, the irradiation crosslinking process of polypropylene containing a polyfunctional monomer having an acryloyloxy group giving a specific gel-dose curve has been studied by measurement of infrared absorption spectrum and oxygen absorptivity in comparison with the nonenhanced system. (author)

28

A Pilot Study Comparing Anatomic Failure after Sacrocolpopexy with Absorbable or Permanent Sutures for Vaginal Mesh Attachment  

Science.gov (United States)

Objectives: To describe anatomic failure rates for sacrocolpopexy in groups receiving either delayed absorbable or permanent monofilament suture for mesh attachment to the vagina. Methods: We reviewed the medical records of 193 women who underwent sacrocolpopexy with 2 different types of sutures attaching polypropylene mesh to the vagina: delayed absorbable sutures (median follow-up, 43 weeks) and permanent sutures (median follow-up, 106 weeks). Vaginal apical failure was defined as Point C greater than or equal to half of the total vaginal length. Anterior-posterior compartmental failures were defined as Point Ba and/or Point Bp more than 0 cm. Fisher exact and ?2 tests were used to compare failure rates. There were no documented suture erosions in the delayed absorbable monofilament suture group during the review period. Two patients in the permanent suture group were found to have permanent suture in the bladder more than 30 weeks after the index procedure. Results: Failure rates for the 45 subjects in the delayed absorbable group and 148 subjects in the permanent suture group were similar (4.4% vs 3.4%, p = 0.74) and not statistically different in any compartment: apical (0% vs 1.4%, p = 0.43), anterior (4.4% vs 2%, p = 0.38), or posterior (0% vs 1.4%, p = 0.43). Conclusions: Delayed absorbable monofilament suture appears to be a reasonable alternative to permanent suture for mesh attachment to the vagina during sacrocolpopexy. The use of delayed absorbable suture could potentially prevent complications of suture erosion into the bladder or vagina remote from the time of surgery. PMID:25662525

Tan-Kim, Jasmine; Menefee, Shawn A; Lippmann, Quinn; Lukacz, Emily S; Luber, Karl M; Nager, Charles W

2014-01-01

29

[New generation of suturing apparatus].  

Science.gov (United States)

For the last 20 years many varieties of suturing instruments for different branches of surgery have been designed. The main trend in the design of suturing instruments is the use of plate matrices, when the tissue to be sutured is placed between the matrix and the stapling part, as well as the use of needle-shaped matrices, when the tissue to be sutured is pierced with a curved needle having a groove on its inner surface for directing and bending staple ends. PMID:7029194

Kapitanov, N N; Petrova, N P

1981-01-01

30

Influence of suture regularity on corneal astigmatism after penetrating keratoplasty  

DEFF Research Database (Denmark)

Abstract. Purpose: To investigate whether suture regularity affects corneal astigmatism after keratoplasty. Methods: Twenty-one patients undergoing penetrating keratoplasty for various corneal diseases were included in the study. The grafts were sutured in place using a single-running Nylon 10-0 suture, taking 24 bites. Immediately after surgery, standard calibrated images of the grafted eye were captured and stored. Using a dedicated image analysis programme, stitches and needle points were identified, and a number of suture regularity variables were calculated. Corneal topographic images were obtained before suture removal (12 months after surgery) and 3 months after suture removal (18 months after surgery). Topographic measures of astigmatism [surface regularity (SRI), surface asymmetry index (SAI) and simulated keratometric astigmatism] were calculated and correlated with the computed suture regularity variables. Results: The average stitch length was 3.04 +/- 0.28 mm and the distance between the outer needle points was 2.53 +/- 0.09 mm. The SRI was 1.26 +/- 0.36 and the SAI was 1.59 +/- 0.67 after 12 months; these decreased to 1.03 +/- 0.48 and 0.92 +/- 0.46 after 18 months, respectively. Corneal astigmatism was 6.38 +/- 2.99 and 5.87 +/- 3.13 dioptres after 12 and 18 months, respectively. Suture regularity did not affect SAI, SRI or corneal astigmatism significantly 12 months after surgery. Eighteen months after surgery (3 months after suture removal), the standard deviation on the original stitch length was found to significantly increase corneal astigmatism. In addition, the size of the counter-clockwise angle between stitch and graft radian was correlated significantly with a lower SRI. Conclusion: The origin of corneal astigmatism after penetrating keratoplasty is multifaceted. Regular stitch length and stitch advancement on the surface appears to improve the optical quality of the graft after suture removal. Factors such as stitch depth, suture tension and variations in wound construction might also beimportant predictors of corneal astigmatism after penetrating keratoplasty.

Hjortdal, Jesper; SØndergaard, Anders

2011-01-01

31

Radiation degradation of polypropylene  

International Nuclear Information System (INIS)

Post-irradiation degradation of isotactic polypropylene irradiated by Co60-?-ray has been followed for 12 months. Effects of irradiation doses (10 - 100 kGy) up on the change of the structure and mechanical properties as well as flowability of this polymer have been studied. Carbonyl index increases with increasing post-irradiation time. This rate was much higher for doses above 50 kGy. Tensile strength declines with time and those samples irradiated above 50 kGy become quite brittle, just after irradiation. Results reveal that post-irradiation degradation of polypropylene irradiated by ?-ray occurs via chain scission mechanism. (author)

32

Releasable suture technique for trabeculectomy  

Directory of Open Access Journals (Sweden)

Full Text Available A retrospective review of 154 trabeculectomies with releasable sutures was performed to assess the effect of suture release on intraocular pressure (IOP at various postoperative periods. Release of the suture was necessary in 38% of cases. The immediate reduction in IOP was significant (p <0.01 when the suture was released during the first three postoperative weeks. Seventy percent of eyes had a reduction in IOP more than 5 mmHg if released within the first week compared to 20% after the third week. With suture release after the third postoperative week, there was no clinically significant decrease in IOP. The decrease in IOP was similar in eyes undergoing trabeculectomy alone or when cataract extraction through a separate corneal incision was undertaken simultaneously. The period during which release of suture was effective was not prolonged by use of antimetabolites. Complications included a typical windshield-wiper keratopathy (18 eyes, failure to release the suture (13 eyes, epithelial abrasion (6 eyes and a sub-conjunctival bleed (1 eye.

Thomas Ravi

1997-01-01

33

Preliminary stress/strain analysis of laser-soldered and -sutured vascular tissue  

Science.gov (United States)

Stress-strain profiles of welded tissue provide additional means of analysing and comparing laser soldering to alternative anastoinosing techniques. Three groups were created in a rabbit model: (1) nonincised control aortic tissue, (2) longitudinal aortotomies repaired with a 808 nm diodelaser (power density 4.8 watts/cm2) after topical application of fibrinogen mixed with indocyanine green dye (peak absorption 805 nm) , and (3) aortotomies repaired with 6-0 polypropylene suture in a running fashion. The rabbits were sacrificed on 0,l,7,and 28 postoperative days and the fresh aortic specimens were strained until disruption in order to produce a stress-strain profile graph. No significant differences were noted between sutured and bonded aorta at any time interval. Nonincised (which served as a control) aortic tissuewithstood significantly higher stress (p<.05) than both sutured and bonded groups at the time of creation. By seven days after operation, no significant differences were noted between any of the three groups. The only significant difference in modulus (stretchability) identified the sutured aorta to be more rigid than the nonincised group (p<.05). Both sutured and laser bonded anastoinoses are weaker than control aorta initially; however, after an early critical period, both treatments achieve the strength of control aorta. By one nionth post-operatively, sutured anastomoses have the disadvantage of creating a less distensible anastomosis.

Ashton, Robert C., Jr.; Oz, Mehmet C.; Lontz, John F.; Lemole, Gerald M.

1991-06-01

34

Advances in polypropylene based materials  

International Nuclear Information System (INIS)

Polypropylene is an extremely versatile thermoplastic polymer known for its good performance/price ratio, excellent heat, moisture and chemical resistance, favorable processing characteristics and recyclability. Due to its universal properties, polypropylene is applied in numerous industrial fields such as electronic and electrical, automobile, textile, pipeline, etc. Furthermore, the progress in its synthesis and property modification in the last decade has contributed to the development of new polypropylene based materials with advanced performance. This review aims at reporting on some recent developments in polypropylene based materials, such as nano fibers, natural fiber reinforced composites, self-reinforced polypropylene and polypropylene/clay hybrids, that have replaced many types of engineering thermoplastics in high-performance applications. (Author)

35

Craniosynostosis of the lambdoid suture.  

Science.gov (United States)

Craniosynostosis affecting the lambdoid suture is uncommon. The definition of lambdoid craniosynostosis solely applies to those cases demonstrating true suture obliteration, similar to other forms of craniosynostosis. In patients presenting with posterior plagiocephaly, true lambdoid craniosynostosis must be differentiated from the much more common positional molding. It can occur in a unilateral form, a bilateral form, or as part of a complex craniosynostosis. In children with craniofacial syndromes, synostosis of the lambdoid suture most often is seen within the context of a pansynostotic picture. Chiari malformations are commonly seen in multisutural and syndromic types of craniosynostosis that affect the lambdoid sutures. Posterior cranial vault remodeling is recommended to provide adequate intracranial volume to allow for brain growth and to normalize the skull shape. Although many techniques have been described for the correction of lambdoid synostosis, optimal outcomes may result from those techniques based on the concept of occipital advancement. PMID:25210507

Rhodes, Jennifer L; Tye, Gary W; Fearon, Jeffrey A

2014-08-01

36

[Use of Nichrome suture material].  

Science.gov (United States)

The suture material and the method of its application play an important role in the prevention of wound complications. With the use of Nichrome wire thread as the suture material in surgical interventions, the number of postoperative complications significantly was decreased. The Nichrome thread is also used expediently in operative interventions on patients with purulent diseases of the soft tissues, including cases after primary surgical treatment of purulent foci by carbon dioxide laser. PMID:2214555

Skobelkin, O K; Korotki?, I V; Tolstykh, P I; Korotki?, V I; Korotki?, V V; Gertsen, A V

1990-06-01

37

Ag??ZnO(10 0??????????  

Directory of Open Access Journals (Sweden)

Full Text Available ???????????????????Ag??ZnO(10 0????????????????????Ag??ZnO(10 0?????????Ag??ZnO (10 0????????????????????ZnO(10 0???Ag??ZnO(10 0?????????????????Ag??ZnO(10 0?????????????Ag????????????????Ag??????????????????????????????????????????Ag??ZnO(10 0?????p???????p????????Ag??ZnO(10 0?????????????p????Based on the density function theory, we have performed first principles calculations of energetic stability and conductive properties and electronic structure of Ag incorporation on ZnO (10 0 surface, and after calculations, we have analyzed the relaxation of the structure and formation energy of Ag incorporation on ZnO (10 0 surface at different layers. Our results show that com-pared with pure ZnO (10 0, there is an obvious effect on the relaxation of the structure for Ag incorporation on ZnO (10 0 surface. Simultaneously, we found that the formation energy of the Ag incorporation on the first layer is the lowest in all cases. Therefore, Ag incorporation on the first layer is the most stable, which indicates that Ag atom prefers to collect in the surface layer instead of the bulk. And we found that the system for Ag incorporation on ZnO (10 0 surface demonstrates as p-type, which is in favors of fabricating p-type material. However, the ionization of Ag incorporation on ZnO (10 0 surface is much higher, which hinders the electronic ionize.

???

2014-08-01

38

Comparison of two techniques: interrupted mass closure and continuous mass closure with polypropylene in laparotomy  

International Nuclear Information System (INIS)

Wound dehiscence is an acute wound failure. It commonly presents about one week after surgery and may be preceded by a serosanguinuous discharge. Wound dehiscence is an important cause of postoperative morbidity and mortality. To compare the early postoperative complications of closure of laparotomy wound by interrupted mass closure and continuous mass closure techniques. Sixty patients were included in this study and divided in two groups; group A and group B. Closure of laparotomy wound with monofilament polypropylene No.1 suture by interrupted mass closure technique for group A and continuous mass closure technique with same suture material in group B was done. In group A, 2 patients developed wound infection and 1 patient was found with wound dehiscence, while in group B, 3 patients suffered wound infection and 2 patients developed wound dehiscence. The closure of laparotomy wound by interrupted mass closure technique with polypropylene No.1 is better closure technique with low rate of wound infection and wound dehiscence as compared to continuous suturing technique with same suture material. (author)

39

Models of cranial suture biology.  

Science.gov (United States)

Craniosynostosis is a common congenital defect caused by premature fusion of cranial sutures. The severe morphologic abnormalities and cognitive deficits resulting from craniosynostosis and the potential morbidity of surgical correction espouse the need for a deeper understanding of the complex etiology for this condition. Work in animal models for the past 20 years has been pivotal in advancing our understanding of normal suture biology and elucidating pathologic disease mechanisms. This article provides an overview of milestone studies in suture development, embryonic origins, and signaling mechanisms from an array of animal models including transgenic mice, rats, rabbits, fetal sheep, zebrafish, and frogs. This work contributes to an ongoing effort toward continued development of novel treatment strategies. PMID:23154351

Grova, Monica; Lo, David D; Montoro, Daniel; Hyun, Jeong S; Chung, Michael T; Wan, Derrick C; Longaker, Michael T

2012-11-01

40

Tension of knotted surgical sutures shows tissue specific rapid loss in a rodent model  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Every surgical suture compresses the enclosed tissue with a tension that depends from the knotting force and the resistance of the tissue. The aim of this study was to identify the dynamic change of applied suture tension with regard to the tissue specific cutting reaction. Methods In rabbits we placed single polypropylene sutures (3/0 in skin, muscle, liver, stomach and small intestine. Six measurements for each single organ were determined by tension sensors for 60 minutes. We collected tissue specimens to analyse the connective tissue stability by measuring the collagen/protein content. Results We identified three phases in the process of suture loosening. The initial rapid loss of the first phase lasts only one minute. It can be regarded as cutting through damage of the tissue. The percentage of lost tension is closely related to the collagen content of the tissue (r = -0.424; p = 0.016. The second phase is characterized by a slower decrease of suture tension, reflecting a tissue specific plastic deformation. Phase 3 is characterized by a plateau representing the remaining structural stability of the tissue. The ratio of remaining tension to initial tension of phase 1 is closely related to the collagen content of the tissue (r = 0.392; p = 0.026. Conclusions Knotted non-elastic monofilament sutures rapidly loose tension. The initial phase of high tension may be narrowed by reduction of the surgeons' initial force of the sutures' elasticity to those of the tissue. Further studies have to confirm, whether reduced tissue compression and less local damage permits improved wound healing.

Klink Christian D

2011-12-01

41

Torsion of monofilament and polyfilament sutures under tension decreases suture strength and increases risk of suture fracture.  

LENUS (Irish Health Repository)

A continuous running suture is the preferential method for abdominal closure. In this technique the suture is secured with an initial knot and successive tissue bites are taken. At each tissue bite, the needle is rotated through the tissue; in doing so, the suture can twist around the knot which acts as an anchor.

Hennessey, D B

2012-08-01

42

The radiation degradation of polypropylene  

International Nuclear Information System (INIS)

Polypropylene is used extensively in the manufacture of disposable medical devices because of its superior properties. Unfortunately this polymer does not lend itself well to radiation sterilization, undergoing serious degradation which affects the mechanical properties of the polymer. In this paper the effects of radiation on the mechanical and physical properties of polypropylene are discussed. A programme of research to minimize the radiation degradation of this polymer through the addition of crosslinking agents to counteract the radiation degradation is proposed. It is furthermore proposed that a process of annealing of the irradiated polymer be investigated in order to minimize the post-irradiation degradation of the polypropylene

43

Superhydrophobic surfaces from various polypropylenes.  

Science.gov (United States)

Superhydrophobic surfaces were prepared from solutions of isotactic polypropylenes of various molecular weights using soft chemistry. Varying the conditions of the experiments (polymer concentration and initial amount of the coated solution) allowed us to optimize the superhydrophobic behavior of the polymer film. Results show that decreasing the concentration and/or film thicknesses decreases the probability to get superhydrophobicity for all polypropylenes tested. Measurement and analysis of advancing and receding contact angles as well as estimation of surface homogeneity were performed. Similar results were obtained with syndio- as well as atactic polypropylenes. PMID:18646781

Rioboo, R; Voué, M; Vaillant, A; Seveno, D; Conti, J; Bondar, A I; Ivanov, D A; De Coninck, J

2008-09-01

44

Contact structures, sutured Floer homology and TQFT  

CERN Document Server

We describe the natural gluing map on sutured Floer homology which is induced by the inclusion of one sutured manifold (M',\\Gamma') into a larger sutured manifold (M,\\Gamma), together with a contact structure on M-M'. As an application of this gluing map, we produce a (1+1)-dimensional TQFT by dimensional reduction and study its properties.

Honda, Ko; Matic, Gordana

2008-01-01

45

Rheological properties of polypropylene nanocomposites  

International Nuclear Information System (INIS)

In this work, composites of polypropylene with a master batch to obtain clay containing nano composites were obtained. The materials were characterized by X ray diffraction, small angle X-ray scattering and by rheological analysis. (author)

46

Polypropylene/clay nanocomposites revisited  

OpenAIRE

This thesis is devoted to the optimization of polypropylene (PP)/clay nanocomposites preparation by trying to resolve or find alternatives to the actual limitations of producing PP/clay nanocomposites which restrain their industrial development. A large part of this work is focused on the study and optimization of functionalized polypropylenes as compatibilizers and an optimized PP-graft-maleic anhydride (PP-g-MA), having significantly higher graft content than classic PP-g-MAs, was selected....

Rousseaux, Dimitri

2010-01-01

47

The double loop mattress suture  

OpenAIRE

An interrupted stitch type with favorable tissue characteristics will reduce local wound complications. We describe a novel high-strength, low-tension repair for the interrupted closure of skin, cartilage, and muscle, the double loop mattress stitch, and compare it experimentally with other interrupted closure methods. The performance of the double loop mattress technique in porcine cartilage and skeletal muscle is compared with the simple, mattress, and loop mattress interrupted sutures in b...

Biddlestone, John; Samuel, Madan; Creagh, Terry; Ahmad, Tariq

2014-01-01

48

Radiation crosslinking of polypropylene  

International Nuclear Information System (INIS)

The radiation crosslinking of polypropylene (PP) with several kinds of polyfunctional monomers has been examined. Formerly many kinds of PP crosslinking methods have been reported, but these have some problems, such as limitations on the thickness of sheets and the degradation of the resin caused by irradiation. We have found that the polyfunctional monomers can be classified into three types by the irradiation dose necessary for crosslinking. In particular, we have developed a new crosslinking method using a specific crosslinking coagent having an acryloyloxy group with a very low required irradiation dose. If this type of monomer is used, 0.5 Mrad is enough to saturate the crosslinking, while the other two types require more than 5 Mrad. The degree of crosslinking is estimated by the gel fraction, modulus of the molten sheet and that of degradation by elongation and oxidation induction time. The crosslinked PP obtained by this method has many good properties, such as a high modulus, large elongation, and high heat resistance. This method may be applied in the manufacture of foamy and other heat resistant materials. (author)

49

The optimal blend ratio of recycling polypropylene waste with pure polypropylene  

International Nuclear Information System (INIS)

Blends of thermomechanical degraded polypropylene and virgin polypropylene materials have been prepared with different compostttion by weight. To produce the same end-use items, mechanical properties showed that the optimal blend ratio by weight is 25% of Rafia polypropylene waste to 75% of virgin polypropylene. Blends containing ratios by weight of 40% Rafia polypropylene waste (R-PP). to 60% of either virgin polypropylene (V-PP), or photo-oxidized degraded polypropylene (W--PP) are both suitable to produce agricultural crates of acceptable performance. The experimental results are explained in terms of structural and morphological changes. (author). 19 refs., 8 figs.,3 tabs

50

Load to failure of common meniscal repair techniques: effects of suture technique and suture material.  

Science.gov (United States)

Success of meniscal repair with early or immediate motion depends on the ability of the suture fixation to withstand the loads applied. Vertical and horizontal mattress suture techniques were tested using 2-0 Ethibond, and 0-PDS and 1-PDS sutures (Ethicon, Somerville, NJ). Mulberry knot technique was tested with 0-PDS and 1-PDS sutures. Twenty menisci (60 sutures) were tested for each suture material. Sutures were placed 3 to 4 mm from the peripheral edge of the meniscus with double barreled cannulas for vertical and horizontal mattress techniques or a spinal needle for the mulberry knot technique, reproducing clinical techniques of meniscal repair. Mechanical testing of suture fixation was performed to failure at a rate of 10 mm/min on a MTS material testing system (MTS Systems Corp, Minneapolis, MN). Suture pullouts were reported as the load displacement to failure from the inner fragment only, because clinical failure would ensue should a suture pull through the inner fragment of a tear. Vertical mattress technique with 1-PDS suture had significantly greater load to failure than any other combination (P suture types, with 1-PDS proving best compared with 0-PDS, which was stronger than 2-0 Ethibond. Selection of suture material had the greatest impact on vertical mattress load to failure and was not important to the strength of the other techniques. PMID:9442327

Post, W R; Akers, S R; Kish, V

1997-12-01

51

Radiation effect on stabilized polypropylene  

International Nuclear Information System (INIS)

Radiation-induced oxidative degradation of stabilized polypropylene films using Co-60 ? irradiation at room temperature under different irradiation conditions (vacuum and oxygen) was investigated. Gas evolution, oxygen consumption, and mechanical properties were studied and analyzed quantitatively. The G values for the evolved gases during irradiation of stabilized polypropylene films under vacuum and in presence of oxygen are given. The stabilized polypropylene, irradiated at low doses under different conditions (air, oxygen, and vacuum), shows mechanical properties almost similar to those of the unirradiated one. However, at higher doses the mechanical properties were sharply decreased and deterioration was enhanced in the presence of oxygen due to the oxidative degradation. On the other hand, post-irradiation effect on the stabilized polypropylene irradiated up to 0.02 MGy under vacuum, was studied at various annealing temperatures and different storage time at room temperature. Molecular weight distribution curves for polypropylene samples irradiated in air atmosphere show that degradation of the high molecular weight chains is the predominant process in the range of irradiation doses under investigation. (author)

52

Abdominal wound closure: choice of suture1  

OpenAIRE

Experiments were designed to test suture materials for their use in potentially infected abdominal wound closure. The nearest to the ideal, at present available, is a monofilament nonabsorbable suture, the one tested being monofilament nylon. The suture retained adequate strength in the infected and noninfected state over a 70-day period. This is particularly important as infection has been shown to result in low wound strength in the early phases of healing. The monofilamentous nature of thi...

Bucknall, T. E.

1981-01-01

53

The cell biology of suturing tendons  

OpenAIRE

Trauma by suturing tendon form areas devoid of cells termed “acellular zones” in the matrix. This study aimed to characterise the cellular insult of suturing and acellular zone formation in mouse tendon. Acellular zone formation was evaluated using single grasping sutures placed using flexor tendons with time lapse cell viability imaging for a period of 12 h. Both tension and injury were required to induce cell death and cell movement in the formation of the acellular zone. DNA fragmenta...

Wong, J. K. F.; Alyouha, S.; Kadler, K. E.; Ferguson, M. W. J.; Mcgrouther, D. A.

2010-01-01

54

Suturing techniques and postoperative management in penetrating keratoplasty in the United Kingdom  

Directory of Open Access Journals (Sweden)

Full Text Available Richard MH Lee,1 Fook Chang Lam,1 Tassos Georgiou,1 Bobby Paul,1 Kong Yong Then,1 Ioannis Mavrikakis,1 Venkata S Avadhanam,1 Christopher SC Liu1,21Sussex Eye Hospital, Brighton, United Kingdom; 2Tongdean Eye Clinic, Hove, United KingdomAims: To report on the suturing techniques and aspects of postoperative management in penetrating keratoplasty in the United Kingdom.Methods: A postal questionnaire was sent to 137 ophthalmic consultants identified from a Royal College of Ophthalmology database as having a special interest in anterior segment surgery. The questionnaire surveyed surgeon preferences for surgical and suturing technique for penetrating keratoplasty surgery, and the postoperative care of corneal grafts.Results: In all, 68% of questionnaires were completed and returned: 73% of respondents used a Flieringa ring or equivalent, 94% routinely used cardinal sutures, with 50.5% removing them at the end of the procedure. The most common suturing technique for routine penetrating keratoplasty was a single continuous suture (35%. In these cases, a 10/0 nylon suture was used by 89%. Sixty-six percent changed their technique in high-risk cases, 52% used a 3-1-1 knot, and 75% made a distinction between a reef and granny knot, with 76% using a reef. Thirty percent buried the knots within the donor material, and 29% within the host tissue. Twenty-five percent had no routine time for graft suture removal, but 41% removed them between 1 and 2 years post-surgery. After suture removal, 98% used steroids and 88% used topical antibiotics. Thirty-four percent stopped topical steroids before suture removal, with 38% stopping topical steroids more than 3 months prior to suture removal.Conclusion: This survey demonstrates that there is considerable variation in suturing techniques and postoperative care for penetrating keratoplasty. These significant variations in practice need to be considered when interpreting outcomes and research.Keywords: corneal graft, penetrating keratoplasty, anterior segment surgery, cornea, corneal surgery, corneal transplantation

Lee RM

2012-08-01

55

Degradation of polypropylene by ionizing radiation  

International Nuclear Information System (INIS)

Protection of polypropylene against effects of ionizing radiation requires effective additives that inhibit radical processes. Hindered amine light stabilizers are considered as the agents fulfilling such demands. We found that they scavenge radicals in amorphous phase of isotactic polypropylene, decrease radiation damage determined on a basis of apparent viscosity reduction and facilitate nucleation. Other aspect of polypropylene degradation was studied in its blends with elastomer styrene-butadiene-styrene (SBS). The phase separation results in independent and parallel radiolysis of both components. The post-irradiation effects in polypropylene proceed faster if it is a constituent of PP/SBS blend; in consequence the degradation of polypropylene is then inhibited. (author)

56

A randomised comparison of polydioxanone (PDS) and polypropylene (Prolene) for abdominal wound closure.  

OpenAIRE

Two hundred and eighty four patients undergoing laparotomy by vertical incision were randomly allocated to closure with interrupted mass sutures of No. 1 polydioxanone (PDS) or No. 1 polypropylene (Prolene). Dehiscence occurred in 0.7% of the PDS group but in 6.4% of the Prolene group (P = 0.018). Wound infection occurred in 8.6% of the PDS group and 15.4% of the Prolene group (P = 0.1). One hundred and ninety patients attended for review at a minimum of one year. Incisional herniation, usual...

Cameron, A. E.; Parker, C. J.; Field, E. S.; Gray, R. C.; Wyatt, A. P.

1987-01-01

57

Nursing sutures in hospital emergency.  

Directory of Open Access Journals (Sweden)

Full Text Available The wounds occupy an important place as far as the demands of care in a service of an emergency department, as hospitable as extra hospitable. The nursery staff faces different types of situations related to the wounds as the prevention of the infection that it is akey component in this fight, the accomplishment of aseptic techniques and the formality in the cares.The main aim of this study is to know the suture characteristics that the nursery staff does in our unit. For that a longitudinal descriptive study was realised from January to March of the 2009 using the statistical package SPSS 16.0 for the analysis of the data.According to the obtained results, most of the wounds are incises-bruised, cleanings, located in hands and fingers and that only affect skin. In order to stitch we give local anesthetic, thread of the 3/0 and dressings impregnated with povidona iodized.

Moya Melendez, Raquel.

2010-01-01

58

Lichtenstein inguinal hernioplasty using butyl-2-cyanoacrylate versus sutures. Preliminary experience of a prospective randomized trial.  

Science.gov (United States)

The Lichtenstein hernioplasty has become a popular method in inguinal hernia repair. This study compared two methods of mesh fixation and wound closure. Forty-six men with unilateral inguinal hernia were randomized into two groups. In the control group polypropylene mesh was anchored with 3/0 Dexon sutures, fascia and skin were closed with sutures 3/0 Dexon and 3/0 Monosof. In the study group, the mesh was secured with butyl-2-cyanoacrylate adhesive and the fascia and skin were also glued with the adhesive. The costs of materials, duration of the operation, amount of postoperative analgesic doses, pain score after the first and the 7th postoperative day and return to daily activity were recorded. No recurrences during the mean follow-up of 4.7 months were observed and the cosmetic effect was very good. In the study group with tissue adhesive the patients had significantly lower pain score after the first postoperative day and had a tendency to require less analgetic doses and to return earlier to their daily activity. Duration of the operation was similar in both groups. The cost of sutures and tissue adhesive used in both procedures was comparable. The use of tissue adhesive in mesh fixation and wound closure seems to be a promising technique in Lichtenstein hernia repair. PMID:15591746

Nowobilski, W; Dobosz, M; Wojciechowicz, T; Mionskowska, Lucjanna

2004-01-01

59

Positron irradiation effects on polypropylene  

OpenAIRE

Positron irradiation effects on polypropylene (PP) and polyethylene during the positron lifetime measurements have been studied in detail. The effect, which was to decrease I3, has been found to be larger in air than in vacuum. For PP, when the lifetime measurements were performed at temperatures above 348K, the radiation effect was scarcely observable. However at low temperature the radiation effect was accumulated and I3 was decreased during the measurements. Irradiation of Co-60 ?-ray up ...

Suzuki, T.; Miura, T.; Oki, Y.; Numajiri, M.; Kondo, K.; Ito, Y.

1993-01-01

60

Rheological properties of polypropylene/ attapulgite nanocomposite.  

Science.gov (United States)

The rheological properties of nanocomposites consisting of organic modified attapulgite and polypropylene are investigated. The morphology of the nanocomposites was studied with scanning electron microscopy and X-ray diffraction. Linear dynamic viscoelasticity and steady state flow step of the nanocomposites are presented. For the nanocomposites, the deviation from linear behavior occurs earlier than pure polypropylene at the strain. The storage moduli, loss moduli and dynamic viscosities of the nanocomposites increase monotonically with organoclay concentration. However, the nanocomposites show greater shear thinning tendency than pure polypropylene because of the orientation of the organoclay fibers. Therefore, the nanocomposites have higher moduli but better processibility compared with pure polypropylene. PMID:21125882

Zhang, Xiaohu; Guo, Jinshan; Zhang, Liji; Yang, Shiyuan; Zhang, Jie; He, Yutao

2010-08-01

61

Twist1 homodimers enhance FGF responsiveness of the cranial sutures and promote suture closure  

OpenAIRE

Haploinsufficiency of the transcription factor TWIST1 is associated with Saethre-Chotzen Syndrome and is manifested by craniosynostosis, which is the premature closure of the calvaria sutures. Previously, we found that Twist1 forms functional homodimers and heterodimers that have opposing activities. Our data supported a model that within the calvaria sutures Twist1 homodimers (T/T) reside in the osteogenic fronts while Twist/E protein heterodimers (T/E) are in the mid-sutures. Twist1 haploin...

Connerney, Jeannette; Andreeva, Viktoria; Leshem, Yael; Mercado, Miguel A.; Dowell, Karen; Yang, Xuehei; Lindner, Volkhard; Friesel, Robert E.; Spicer, Douglas B.

2008-01-01

62

Animal Models of Cranial Suture Biology  

OpenAIRE

Craniosynostosis is a common congenital defect caused by premature fusion of cranial sutures. The severe morphological abnormalities and cognitive deficits resulting from craniosynostosis and the potential morbidity of surgical correction espouse the need for a deeper understanding of the complex etiology for this condition. Work in animal models over the past twenty years has been pivotal in advancing our understanding of normal suture biology and elucidating pathological disease mechanisms....

Grova, Monica; Lo, David D.; Montoro, Daniel; Hyun, Jeong S.; Chung, Michael T.; Wan, Derrick C.; Longaker, Michael T.

2012-01-01

63

Massive obstetric haemorrhage following removal of a cervical suture  

OpenAIRE

The authors present an unusual case of massive ante partum haemorrhage following removal of a cervical suture. This patient was admitted for routine removal of a McDonald’s cervical suture at 37 weeks gestation. The suture was densely adherent and after removal she suffered a haemorrhage of 2500 ml from where the suture was removed which led to fetal distress and an emergency caesarean section. The cervix was sutured and a vaginal pack inserted. During the procedure she developed hypovolaem...

Howarth, Louise Ann; Sherliker, Sarah

2011-01-01

64

Radiation stabilization of polypropylene by phenolic stabilizers  

International Nuclear Information System (INIS)

The radiation stability of polypropylene stabilized with two phenolic stabilizers and synergistic behaviour of these stabilizers have been investigated. The variation of carbonyl index and mechanical properties of stabilized and unstabilized polypropylene has been followed for 6 months after irradiation at 25 kGy. The extent of chain scission has been followed by measuring the change in apparent viscosity. (author)

65

Welded polypropylene liners for large descaling tanks  

Science.gov (United States)

Liners for nitric and hydrofluoric acid tanks show no sign of deterioration after 18 months of continuous use. Each side of each edge of the polypropylene sheets is chamfered, and sheets are welded from both sides with polypropylene filler rod and a special hot-air welding torch.

Abel, H. P.

1971-01-01

66

The history and evolution of sutures in pelvic surgery.  

Science.gov (United States)

The purpose of the study is to review the history and innovations of sutures used in pelvic surgery. Based on a review of the literature using electronic- and hand-searched databases we identified appropriate articles and gynaecology surgical textbooks regarding suture for wound closure. The first documented uses of suture are explored and then the article focuses on the use of knotted materials in pelvic surgery. The development of suture of natural materials is followed chronologically until the present time where synthetic suture is implanted during countless surgeries every day. This millennial history of suture contains an appreciation of the early work of Susruta, Celsus, Paré and Lister, including a survey of some significant developments of suture methods over the last 100 years. Most surgeons know little about the history and science of sutures. A retrospective view of suture is critical to the appreciation of the current work and development of this common tool. PMID:21357979

Muffly, Tyler M; Tizzano, Anthony P; Walters, Mark D

2011-03-01

67

Skin closure in vascular neurosurgery: A prospective study on absorbable intradermal suture versus nonabsorbable suture  

Science.gov (United States)

Background: The craniotomy performed with minimal hair removal and closure with intradermal suture alone is an option in neurosurgical procedures, which can help faster psychological recovery of the patient, as it allows a better cosmetic result. This study is aimed at evaluating if such method is safe and effective, compared with continuous skin sutures with 2-0 nylon. Methods: We analyzed the sutures in 117 patients undergoing craniotomies for cerebral aneurysm clipping. In the case group (n = 49), closure of the scalp was performed only with intradermal absorbable sutures using wire Monocryl® 2-0. In the control group (n = 68), closure was performed with continuous suture using 2-0 nylon. Results: The case group was composed of 49 patients in whom just intradermal suture was performed. One (2.2%) patient developed wound infection and was given proper medical treatment. No cases of dehiscence or cerebrospinal fluid leaks were observed. The control group was composed of 68 patients in whom the skin was closed with 2-0 nylon continuous suture. Three (5.3%) patients developed wound infection and were given proper medical treatment. There were no cases of wound dehiscence. The overall infection rate in the control group was 4%. There was no statistically significant difference in the number of wound infections between the two groups (P = 0.73). Conclusion: The closure with intradermal suture alone in craniotomies is as safe as the traditional skin closure with nylon sutures, besides eliminating the need for suture removal and providing a cosmetic advantage. PMID:23050208

Pereira, Julio Leonardo Barbosa; Vieira, Gerival; de Albuquerque, Lucas Alverne Freitas; Mendes, George de Albuquerque Cavalcanti; Salles, Ludmila Rezende; de Souza, André Felipe Ferreira; Dellaretti, Marcos; de Sousa, Atos Alves

2012-01-01

68

Double suture technique to delineate PASTA lesions.  

Science.gov (United States)

A common method of treating PASTA (partial articular surface tendon avulsion) lesions involves completing the tear followed by arthroscopic repair. Frequently, the boundaries of the tear are difficult to determine from the bursal side with the use of a single marking stitch. Therefore, we describe a simple technique that allows the surgeon to reproducibly define the boundaries of the partial tear. Following a standard arthroscopic examination of the articular portion of the shoulder joint, the PASTA lesion is identified. A spinal needle is introduced and the most anterior and posterior aspects of the tear are marked by passing 2 sutures. Following a bursectomy, the 2 sutures that clearly define the boundaries of the tear are identified. The tear is then completed by "connecting the dots" outlined by the sutures and an arthroscopic repair is performed in the standard manner. PMID:16762713

Sperling, John W; Dahm, Diane L

2006-06-01

69

Flexor Tenorrhaphy Using Absorbable Suture Materials  

Directory of Open Access Journals (Sweden)

Full Text Available Background Nonabsorbable sutures are favorable for repairing flexor tendons. However,absorbable sutures have performed favorably in an animal model.Methods Two-strand sutures using the interlocking modified Kessler method with polydioxanoneabsorbable sutures 4-0 were used to repair completely ruptured flexor tendons in 55 fingersfrom 41 consecutive patients. The medical records of average 42 follow up weeks were analyzedretrospectively. The data analyzed using the chi-squared test, and Fisher’s exact test was used forpostoperative complications. The results were compared with those of other studies.Results Among the index, middle, ring, and little fingers were injured in 9, 17, 16, and13 fingers, respectively. The injury levels varied from zone 1 to 5. Of the 55 digits in ourstudy, there were 26 (47% isolated flexor digitorum profundus (FDP injuries and 29 (53%combined FDP and with flexor digitorum superficialis injuries. Pulley repair was also conducted.Concomitant injuries of blood vessels and nerves were found in 17 patients (23 fingers; nerveinjuries occurred in 5 patients (10 fingers. Two patients had ruptures (3.6%, and one patienthad two adhesions (3.6%. Using the original Strickland criteria, all the patients were assessedto be excellent or good. Also, fibrosis and long-term foreign body tissue reactions such as stitchgranuloma were less likely occurred in our study. Compared to the Cullen’s report that usednonabsorbable sutures, there was no significant difference in the rupture or adhesion rates.Conclusions Therefore, this study suggests that appropriate absorbable core sutures can beused safely for flexor tendon repairs.

Hyung Joo Kang

2012-07-01

70

Optimal Suturing Technique and Number of Sutures for Surgical Implantation of Acoustic Transmitters in Juvenile Salmonids  

Energy Technology Data Exchange (ETDEWEB)

The size reduction of acoustic transmitters has led to a reduction in the length of incision needed to implant a transmitter. Smaller suture knot profiles and fewer sutures may be adequate for closing an incision used to surgically implant an acoustic microtransmitter. As a result, faster surgery times and reduced tissue trauma could lead to increased survival and decreased infection for implanted fish. The objective of this study was to assess the effects of five suturing techniques on mortality, tag and suture retention, incision openness, ulceration, and redness in juvenile Chinook salmon Oncorhynchus tshawytscha implanted with acoustic microtransmitters. Suturing was performed by three surgeons, and study fish were held at two water temperatures (12°C and 17°C). Mortality was low and tag retention was high for all treatments on all examination days (7, 14, 21, and 28 days post-surgery). Because there was surgeon variation in suture retention among treatments, further analyses included only the one surgeon who received feedback training in all suturing techniques. Incision openness and tissue redness did not differ among treatments. The only difference observed among treatments was in tissue ulceration. Incisions closed with a horizontal mattress pattern had more ulceration than other treatments among fish held for 28 days at 17°C. Results from this study suggest that one simple interrupted 1 × 1 × 1 × 1 suture is adequate for closing incisions on fish under most circumstances. However, in dynamic environments, two simple interrupted 1 × 1 × 1 × 1 sutures should provide adequate incision closure. Reducing bias in survival and behavior tagging studies is important when making comparisons to the migrating salmon population. Therefore, by minimizing the effects of tagging on juvenile salmon (reduced tissue trauma and reduced surgery time), researchers can more accurately estimate survival and behavior.

Deters, Katherine A.; Brown, Richard S.; Boyd, James W.; Eppard, M. B.; Seaburg, Adam

2012-01-02

71

Influence of the elastomeric polypropylene addition on the properties of commercial metallocenic polypropylene  

OpenAIRE

Polypropylene with special properties can be obtained by metallocenic catalysts. These catalytic systems represent the beginning of a new age in polyolefins technology. In this work, the influence of the addition of a syndiotactic polypropylene (s-PP) on the processability and mechanical properties of a commercial isotactic polypropylene (i-PP) obtained by metallocenic catalysts was evaluated. Increasing addition of s-PP promoted better processability, with an increase in the impact strength ...

Marques, Maria Fa?tima V.; Mariana Poloponsky; Érica Gervasoni Chaves

2001-01-01

72

Nanostructured medical sutures with antibacterial properties.  

Science.gov (United States)

Bacterial repellence in suture materials is a desirable property that can potentially improve the healing process by preventing infection. We describe a method for generating nanostructures at the surface of commercial sutures of different composition, and their potential for preventing biofilm formation. We show how bacteria attachment is altered in the presence of nanosized topographies and identify optimum designs for preventing it without compromising biocompatibility and applicability in terms of nanostructure robustness or tissue friction. These studies open new possibilities for flexible and cost-effective realization of topography-based antibacterial coatings for absorbable biomedical textiles. PMID:25818435

Serrano, Cristina; García-Fernández, Luis; Fernández-Blázquez, Juan Pedro; Barbeck, Mike; Ghanaati, Shahram; Unger, Ron; Kirkpatrick, James; Arzt, Eduard; Funk, Lutz; Turón, Pau; Del Campo, Aránzazu

2015-06-01

73

Multiaxial yield behaviour of polypropylene  

Directory of Open Access Journals (Sweden)

Full Text Available In order to characterize the yield behavior of polypropylene as a function of pressure and to verify the applicability of the Drucker-Prager yield function, various tests were conducted to cover a wide range of stress states from uniaxial tension and compression to multiaxial tension and confined compression. Tests were performed below and above the glass transition temperature, to study the combined effect of pressure and temperature. The pressure sensitivity coefficient as an intrinsic material parameter was determined as a function of temperature. Increasing pressure sensitivity values were found with increasing temperature, which can be related to the change in the free volume and thus, to the enhanced molecular mobility. A best-fit Drucker-Prager yield function was applied to the experimental yield stresses and an average error between the predictions and the measurements of 7 % was obtained.

Lang R.

2010-06-01

74

The history and evolution of sutures in pelvic surgery  

OpenAIRE

The purpose of the study is to review the history and innovations of sutures used in pelvic surgery. Based on a review of the literature using electronic- and hand-searched databases we identified appropriate articles and gynaecology surgical textbooks regarding suture for wound closure. The first documented uses of suture are explored and then the article focuses on the use of knotted materials in pelvic surgery. The development of suture of natural materials is followed chronologically unti...

Muffly, Tyler M.; Tizzano, Anthony P.; Walters, Mark D.

2011-01-01

75

Horizontal Running Mattress Suture Modified with Intermittent Simple Loops  

OpenAIRE

Using the combination of a horizontal running mattress suture with intermittent loops achieves both good eversion with the horizontal running mattress plus the ease of removal of the simple loops. This combination technique also avoids the characteristic railroad track marks that result from prolonged non-absorbable suture retention. The unique feature of our technique is the incorporation of one simple running suture after every two runs of the horizontal running mattress suture. To demonstr...

Chacon, Anna H.; Shiman, Michael I.; Strozier, Narissa; Zaiac, Martin N.

2013-01-01

76

Comparison of suture types in the closure of scalp wounds.  

LENUS (Irish Health Repository)

Innovation in practice can benefit patients and healthcare providers but must be evidence based. This article describes a quantitative study of whether absorbable sutures are as beneficial as non-absorbable sutures in the management of simple scalp lacerations in adults. The results suggest that absorbable sutures can provide the same cosmetic and functional results as non-absorbable sutures. Their use can also reduce patient returns and save money and resources.

Bonham, Joseph

2011-06-01

77

The contact invariant in sutured Floer homology  

CERN Document Server

We describe an invariant of a contact 3-manifold with convex boundary as an element of Juh\\'asz's sutured Floer homology. Our invariant generalizes the contact invariant in Heegaard Floer homology in the closed case, due to Ozsv\\'ath and Szab\\'o.

Honda, Ko; Matic, Gordana

2007-01-01

78

[Behavior of resorbable and nonresorbable suture material in lymph vessel suture].  

Science.gov (United States)

After transverse division of the abdominal thoracic duct of the rat, 14 anastomoses were performed using synthetic absorbable (Polyglactin 910, Vicryl) and synthetic non-absorbable (Polyamid 6.6, Ethilon) suture material. The anastomoses were achieved by means of a tension-free technique using interrupted sutures. The follow-up period was from 28 to 133 days. Clinical observation showed that all anastomoses were patent. However, with the aid of staining methods only five out of seven anastomoses were shown to be patent. Using absorbable suture material, a lumen was demonstrable at all anastomoses, while using non-absorbable suture material this could be proved in only four out of seven anastomoses. The foreign body reaction diminished with time when absorbable material was employed, whereas it persisted with non-absorbable material. PMID:6763587

Baumeister, R G; Seifert, J; Wiebecke, B

1982-01-01

79

Highly Filled Polypropylene Rubber Wood Flour Composites  

OpenAIRE

In this research, polypropylene composites filled with Hevea Brasilliensis wood flour at filler content up to 60wt% were prepared and investigated in order to determine the effects of polymer melt flow rate (MFR), number of reprocessing times, filler size, and filler content on thermal and mechanical properties. The results reveal that the composites of polypropylene with higher melt flow rate (lower viscosity) provided greater values of flexural and tensile properties. The study additionally...

Sunan Tiptipakorn; Saroj Jittarom; Sarawut Rimdusit; Watanachai Smittakorn

2011-01-01

80

Transfascial suture in laparoscopic ventral hernia repair; friend or foe?  

Science.gov (United States)

'Suture hernia' is fairly a new and rare type of ventral hernia. It occurs at the site of transfascial suture, following laparoscopic ventral hernia repair (LVHR). Employment of transfascial sutures in LVHR is still debatable in contrast to tackers. Prevention of mesh migration and significant post-operative pain are the pros and cons with the use of transfascial sutures, respectively. We report an unusual case of suture hernia or transfascial hernia, which can further intensify this dispute, but at the same time will provide insight for future consensus. PMID:25883460

Sahu, Diwakar; Das, Somak; Wani, Majid Rasool; Reddy, Prasanna Kumar

2015-01-01

81

Polypropylene nanogel: “Myth or reality”  

International Nuclear Information System (INIS)

The objective of this work is the investigation of the nanogel and microgel formation in modified PP. The modified PP in pellets was synthesized by gamma irradiation of pristine PP under a crosslinking atmosphere of acetylene in dose of 5, 12.5 and 20 kGy, followed by thermal treatment for radical recombination and annihilation of the remaining radicals. The thin film gel of the polypropylenes was obtained by extraction in boiling xylene for period of 12 h at 138 °C, followed by decantation in beaker at room temperature of 25 °C with the total volatilization of the xylene and deposition of dried material film on glass substrate under agitation by Settling process. The thin film gel formed of pristine PP and modified PP (i.e., irradiated) was characterized using scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM) and differential scanning calorimetry (DSC). The PP morphology indicated the nanogels and microgel formation with increase of spherulitic concentration and crystallinity at dose of 12.5 kGy. - Highlights: ? The formation of nanogels comes from irradiated sites prior to crosslink bonds. ? Evolution of nanogels in size creates domains with lower crosslink density and defects. ? In conclusion nanogel is present in the irradiated PP and has crystallinity.

82

Mobility as a mechanism for radiation stabilization of polypropylene  

International Nuclear Information System (INIS)

Termination rates of radiation induced primary alkyl radicals are studied with ESR in polypropylene formulations containing additives that increase main chain mobility. The incorporation of mobilizing additives into polypropylene significantly improves radiation induced mechanical property degradation. (author)

83

Do Absorbable Sutures Exacerbate Presternal Scarring?  

OpenAIRE

We investigated cosmetic outcomes of the midline sternotomy incision. A randomized clinical trial was conducted in 60 patients who underwent surgery through a midline sternotomy incision. Patients were divided into groups A (n=30) and B (n=30). In addition, the incision line was also divided into 2 regions (upper and lower halves) in each group. In group A, the upper half of the skin was closed with absorbable 4-0 braided polyglycolic acid sutures (Sentesor®, Boz; Ankara, Turkey), and the lo...

Durkaya, Suat; Kaptanoglu, Melih; Nadir, Aydin; Yilmaz, Sarper; Cinar, Ziynet; Dogan, Kasim

2005-01-01

84

The "butterfly" suture technique for meniscal repair.  

Science.gov (United States)

One of the important factors effecting meniscal healing is the strength of primary fixation obtained by repairing technique. From this perspective, it is important to choose the technique ensuring a higher primary fixation strength for meniscal repairs. We described a new technique for meniscal repair called "butterfly" technique using Viper device and hypothesized that high primary fixation strength can be obtained with this technique. The study was performed on calve knees. Full-thickness longitudinal tears 2 cm in length and 3 mm medial from the periphery were created in corpora of medial menisci of 14 calves. After creating tears, menisci were divided into two equal groups. In Group 1, two vertical loop sutures 1 cm apart were placed using a Viper device. Whereas in Group 2, tears were repaired using "butterfly" sutures. The mean load to failure was 156.3 ± 13.1 and 186 ± 15.8 N in Group 1 and 2, respectively (p = 0.002). The fixation strength in Group 2 was significantly higher than in Group 1. We suggest that, using Viper device and all-inside "butterfly" suturing techniques, meniscal ruptures with appropriate locations can be repaired with higher primary fixation strength. PMID:20617326

Gunes, Taner; Bostan, Bora; Erdem, Mehmet; Asci, Murat; Sen, Cengiz; Kelestemur, Mehmet Halidun

2011-03-01

85

The Di Giacomo technique: simplified suture passing in SLAP repair.  

Science.gov (United States)

A 30 degrees arthroscope is introduced via the posterior soft spot portal, and an anterosuperior portal is created with the use of a 7-mm disposable cannula. The anterosuperior portal is used for instrumentation. An 18-gauge spinal needle is passed via the portal of Neviaser and the rotator cuff into arthroscopic view above the superior labrum. A No. 1 polydioxanone suture (PDS; Ethicon, Somerville, NJ) is advanced through the spinal needle. An arthroscopic retriever or meniscal clamp is used to retrieve the free end of the suture and bring it out through a small anterior stab wound. A suture anchor is inserted via the anterosuperior portal into the superior neck of the glenoid. The more medial limb of the No. 2 Ethibond suture (Ethicon) from the suture anchor is retrieved with the inferior limb of the No. 1 PDS suture, and both are brought out through the anterosuperior cannula. The opposite end of the No. 1 PDS suture is then manually pulled, while, under direct arthroscopic visualization, the No. 2 Ethibond suture, now tied to the opposite end of the PDS, is pulled through the superior labral tissue. That anchor suture is retrieved and is placed outside the cannula that contains the other anchor suture. Standard arthroscopic knot tying is then employed. PMID:17418338

Selby, Ronald M; Altchek, David W; Di Giacomo, Giovanni

2007-04-01

86

Automatic Detection of Wild-type Mouse Cranial Sutures  

DEFF Research Database (Denmark)

In the study of craniofacial malformations, the cranial sutures are often of interest. The premature fusion of sutures occurring in e.g. Crouzon and Apert syndrome can lead to asymmetric head shape, enlarged intracranial pressure and blindness. In large population studies of such syndromes, automatic detection of the cranial sutures becomes important. We have previously built a craniofacial, wild-type mouse atlas from a set of 10 Micro CT scans using a B-spline-based nonrigid registration method by Rueckert et al. Subsequently, all volumes were registered nonrigidly to the atlas. Using these transformations, any annotation on the atlas can automatically be transformed back to all cases. For this study, two rounds of tracing seven of the cranial sutures, were performed on the atlas by one observer. The average of the two rounds was automatically propagated to all the cases. For validation, the observer traced the sutures on each of the mouse volumes as well. The observer outperforms the automatic approach by approximately 0.1 mm. All mice have similar errors while the suture error plots reveal that suture 1 and 2 are cumbersome, both for the observer and the automatic approach. These sutures can be hard to detect with the eye. We still believe that overall, the errors are not considerable and by qualitatively estimating the accuracy, the automatic sutures are very close to the observer sutures. Our plan is to improve the results by local feature detection methods.

Ólafsdóttir, Hildur; Darvann, Tron Andre

87

Spectroscopic Investigations on Polypropylene -- Carbon Nanofibers Composites  

Science.gov (United States)

Nanocomposites were obtained by high-shear mixing of isotactic polypropylene (Marlex HLN-120-01; Philips Sumika Polypropylene Company) with various amounts of vapor grown carbon nanofibers (PR-24AG; Pyrograf Products, Inc) by utilizing a HAAKE Rheomix at 65 rpm and 180 ^oC for 9 min followed by an additional mixing at 90 rpm for 5 min. Composites loaded with various amounts of vapor grown carbon nanofibers have been prepared. Wide angle X-Ray scattering investigations focus on the effect of carbon nanofibers on the crystalline phases of polypropylene and on the overall crystallinity degree of the polymeric matrix. Raman spectroscopy analysis concentrates on D and G bands. X-band electron spin resonance investigations aim at a better understanding of the purity of carbon nanofibers and of the ratio between conducting and paramagnetic.

Chipara, Mircea; Brian, Jones; Lozano, Karen; Villareal, John R.; Cristian Chipara, Alin; Hernandez, Anna; Dorina Chipara, Magdalena; Sellmyer, David J.

2008-03-01

88

Flammability of polypropylene/organoclay nanocomposites  

International Nuclear Information System (INIS)

The flammabilities of nanocomposites made with three polypropylene grades (homo and copolymers) with 5 wt % of organoclay (Cloisite 20A), 5 or 15 wt % of maleated polypropylene as compatibilizer, and 0, 0.5 or 1 wt % of cis-13-docosenamide (Erucamide) as co-intercalant, were studied using the horizontal burning test UL94HB. Masterbatches prepared in an internal mixer were diluted in the polypropylene matrix using a corotating twin-screw extruder, with different screw configurations and operating at 240 or 480 rpm. Results indicate that the high burning rate of the composites was not affected by the processing conditions. For all formulations was observed a significant reduction in smoke release, lack of dripping and the formation of a char surface layer, that protected the core of the samples. (author)

89

Effect of ?-irradiation on commercial polypropylene based mono and multi-layered retortable food packaging materials  

International Nuclear Information System (INIS)

Irradiation processing of food in the prepackaged form may affect chemical and physical properties of the plastic packaging materials. The effect of ?-irradiation doses (2.5-10.0 kGy) on polypropylene (PP)-based retortable food packaging materials, were investigated using Fourier transform infrared (FTIR) spectroscopic analysis, which revealed the changes happening to these materials after irradiation. The mechanical properties decreased with irradiation while oxygen transmission rate (OTR) was not affected significantly. Colour measurement indicated that Nylon 6 containing multilayer films became yellowish after irradiation. Thermal characterization revealed the changes in percentage crystallinity

90

Effect of ?-irradiation on commercial polypropylene based mono and multi-layered retortable food packaging materials  

Science.gov (United States)

Irradiation processing of food in the prepackaged form may affect chemical and physical properties of the plastic packaging materials. The effect of ?-irradiation doses (2.5-10.0 kGy) on polypropylene (PP)-based retortable food packaging materials, were investigated using Fourier transform infrared (FTIR) spectroscopic analysis, which revealed the changes happening to these materials after irradiation. The mechanical properties decreased with irradiation while oxygen transmission rate (OTR) was not affected significantly. Colour measurement indicated that Nylon 6 containing multilayer films became yellowish after irradiation. Thermal characterization revealed the changes in percentage crystallinity.

George, Johnsy; Kumar, R.; Sajeevkumar, V. A.; Sabapathy, S. N.; Vaijapurkar, S. G.; Kumar, D.; Kchawahha, A.; Bawa, A. S.

2007-07-01

91

Production and properties of polypropylene track membranes  

International Nuclear Information System (INIS)

This paper describes the results of the method of manufacturing of the polypropylene track membranes produced by physicochemical treatment under irradiation of accelerated heavy ions of polymer films. The developed method allows one to produce membranes 0.1-0.2 ?m in diameter and more with an improved structural and physicochemical properties. Polypropylene track membranes of a novel sample are characterized by high homogeneity of pore sizes in magnitude, considerable mechanical strength, increased thermostability and resistance in aggressive media. It opens new fields for their usage. 16 refs., 5 figs., 4 tabs

92

"Luggage-tag" suture fixation of partially dislocated intraocular lenses.  

Science.gov (United States)

There are many techniques for sulcus-suturing dislocated or partially dislocated intraocular lenses. Many involve passing suture or a knot around the end of the haptic before securing the suture to the sclera. However, in some patients, the tip of the dislocated haptic cannot be visualized. We describe a suturing method using vitrectomy techniques that was used in two patients when the end of the haptic could not be visualized. The technique involves passing an untied loop of double-armed suture under the haptic so that it emerges upward between the haptic and the optic. The loop of suture is regrasped from above the haptic and externalized. The free ends are passed through the loop in a manner analogous to a luggage tag, and the knot is secured. This technique may be useful in patients where the tip of the haptic cannot be visualized, or in patients requiring minimal manipulation of the intraocular lens. PMID:11475406

Virata, S R; Holekamp, N M; Meredith, T A

2001-01-01

93

The frontosphenoidal suture: fetal development and phenotype of its synostosis  

International Nuclear Information System (INIS)

Isolated synostosis of the frontosphenoidal suture is very rare and difficult to diagnose. Little has been reported on the clinical presentation and fetal development of this suture. To understand the development of the frontosphenoidal suture and the outcome of its synostosis. We studied the normal fetal development of the frontosphenoidal suture in dry human skulls and the clinical features of four patients with isolated synostosis of the frontosphenoidal suture. The frontosphenoidal suture develops relatively late during the second trimester of pregnancy, which explains the mild phenotype when there is synostosis. This rare craniosynostosis results in a deformity that causes recession of the lateral part of the frontal bone and supraorbital rim, with minimal facial asymmetry. Three-dimensional CT is the best examination to confirm the diagnosis. Isolated frontosphenoidal synostosis should be considered in patients with unilateral flattening of the forehead at birth that does not improve within the first few months of life. (orig.)

94

The frontosphenoidal suture: fetal development and phenotype of its synostosis  

Energy Technology Data Exchange (ETDEWEB)

Isolated synostosis of the frontosphenoidal suture is very rare and difficult to diagnose. Little has been reported on the clinical presentation and fetal development of this suture. To understand the development of the frontosphenoidal suture and the outcome of its synostosis. We studied the normal fetal development of the frontosphenoidal suture in dry human skulls and the clinical features of four patients with isolated synostosis of the frontosphenoidal suture. The frontosphenoidal suture develops relatively late during the second trimester of pregnancy, which explains the mild phenotype when there is synostosis. This rare craniosynostosis results in a deformity that causes recession of the lateral part of the frontal bone and supraorbital rim, with minimal facial asymmetry. Three-dimensional CT is the best examination to confirm the diagnosis. Isolated frontosphenoidal synostosis should be considered in patients with unilateral flattening of the forehead at birth that does not improve within the first few months of life. (orig.)

Mathijssen, Irene M.J.; Meulen, Jacques J.N.M. van der; Adrichem, Leon N.A. van; Vaandrager, J.M.; Vermeij-Keers, Christl [Erasmus MC, University Medical Centre, Department of Plastic and Reconstructive Surgery, Rotterdam (Netherlands); Hulst, Rene R.W.J. van der [University Hospital Maastricht, Department of Plastic and Reconstructive Surgery, Maastricht (Netherlands); Lequin, Maarten H. [Erasmus MC, University Medical Centre, Department of Radiology, Rotterdam (Netherlands)

2008-04-15

95

A technique for introducing looped sutures in flexor tendon repair  

Directory of Open Access Journals (Sweden)

Full Text Available Stronger flexor tendon repairs facilitate early active motion therapy protocols. Core sutures using looped suture material provide 1 ½ to twice the strength of Kessler?s technique (with four strand and six strand Tsuge technique respectively. The technique is well-described and uses preformed looped sutures (supramid. This is not available in many countries and we describe a technique whereby looped sutures can be introduced in flexor tendon repair by the use of 23 G hypodermic needle and conventional 4.0 or 5.0 sutures. This is an alternative when the custom made preformed sutures are not available. This can be practiced in zone 3 to zone 5 repairs. Technical difficulties limit its use in zone 2 repairs.

Kamath B

2006-01-01

96

Massive obstetric haemorrhage following removal of a cervical suture.  

Science.gov (United States)

The authors present an unusual case of massive ante partum haemorrhage following removal of a cervical suture. This patient was admitted for routine removal of a McDonald's cervical suture at 37 weeks gestation. The suture was densely adherent and after removal she suffered a haemorrhage of 2500 ml from where the suture was removed which led to fetal distress and an emergency caesarean section. The cervix was sutured and a vaginal pack inserted. During the procedure she developed hypovolaemic shock requiring 7 units of blood, 4 units of fresh frozen plasma, 1 unit of platelets and 1 unit of cryoprecipitate. Ten days later she was readmitted with a postpartum haemorrhage of 1000 ml requiring further haemostatic sutures to the cervix. PMID:22696714

Howarth, Louise Ann; Sherliker, Sarah

2011-01-01

97

Use of barbed suture in robot-assisted mitral valvuloplasty.  

Science.gov (United States)

Robot-assisted annuloplasty using a mitral band has a major issue: suturing is time consuming because knot tying is performed mechanically under endoscopic view. We suture the mitral band to the native valve by running sutures using the V-Loc barbed suture nonabsorbable wound closure device (Covidien, Mansfield, MA) with 3-0 monofilament. This technique allows rapid suturing of the band to the valve. Although conventional interrupted sutures leave multiple knots protruding on the band, using the V-Loc eliminates the need to tie surgical knots and leaves a clean surface, which may potentially reduce the risk of thrombogenesis. This method is highly useful for robotic mitral annuloplasty. PMID:25555967

Watanabe, Go; Ishikawa, Norihiko

2015-01-01

98

Effectivity of intraoperative adjustable suture technique in horizontal strabismus  

OpenAIRE

AIM:To compare the long-term effectivity of intraoperative adjustable suture technique with traditional non-adjustable strabismus surgery.METHODS:Two hundred and thirty-three patients, who underwent strabismus surgery either with traditional procedures or one-stage intraoperative adjustable suture technique, were included in our long-term follow-up study. One hundred and eighteen patients were evaluated in traditional surgery group (TSG) and 115 who underwent adjustable suture were in the one...

Ayse Gul Kocak Altintas; Hasan Basri Arifoglu; Inci Kocak Midillioglu; Elif Damar Gungor; Saban Simsek

2013-01-01

99

Water Absorption Properties and Morphology of Polypropylene/ Polycarbonate/Polypropylene-graft-Maleic Anhydride Blends  

OpenAIRE

This study investigates the effect of blending polycarbonate (PC) into polypropylene (PP) matrix polymer on water absorption properties and morphology. The blends, containing 5-35% of polycarbonate and 5% compatibilizer, were compounded using twin - screw extruder and fabricated into standard tests samples using compression molding. The compatibilizer used was polypropylene-graft-maleic anhydride (PP-g-MA). In water absorption test, specimens were immersed in distilled water at 23 and 1...

Megat-yusoff, P. S. M.; Abdullah, M. Z.; Mat-shayuti, M. S.

2013-01-01

100

Degradation study of polypropylene (PP) and bioriented polypropylene (BOPP) in the environment  

OpenAIRE

Polymers are vastly employed for numerous purposes in different industrial segments and generate soaring quantities of discarding in the environment. This research analyzed the degradability/biodegradability of polypropylene films (PP) and Bioriented polypropylene (BOPP) polymers after 11 months interred in the São Giácomo landfill in Caxias do Sul. Comparing the buried PP film to a sample of virgin PP, two peaks of degrading activity appeared at the TG curve as well as structure modificati...

Carina Longo; Michele Savaris; Mára Zeni; Rosmary Nichele Brandalise; Ana Maria Coulon Grisa

2011-01-01

101

Techniques and applications of adjustable sutures.  

Science.gov (United States)

The 'rediscovery' of adjustable sutures some 10 years ago has given the ophthalmic surgeon much more confidence in his ability to correct strabismus. Three methods of use are described: during surgery under general anaesthesia with adjustment during the operation using the 'springback' test to centralise the eye; during surgery under general anaesthesia and subsequent adjustment under local anaesthesia using the patient's subjective responses to obtain optimal positioning; and performance of the operation and adjustment under topical local anaesthesia in one procedure. Full details are given of each technique and the indications for their application to particular problems are discussed. PMID:3297111

Fells, P

1987-02-01

102

Radiothermoluminescence of polyethylene and polypropylene mixtures  

International Nuclear Information System (INIS)

The influence of the composition of polyethylene and polypropylene mixture on relaxational behaviour of the composition was studied by the method of radiothermoluminescence. The samples were irradiated by 60Co ?-radiation with absorbed dose rate of 1 MGy. It is shown that the sophisticated spectrum of molecular relaxation is related to structural transitions in three temperature ranges. 6 refs.; 1 tab

103

Morphology of Thermoplastic Elastomers:Stereoblock Polypropylene  

Energy Technology Data Exchange (ETDEWEB)

The morphologies of low-density (0.86 g/cm{sup 3}), elastomeric polypropylene (ePP) derived from bis(2-arylindenyl) hafnium dichloride were investigated using a combination of polarized optical microscopy (OM), differential scanning calorimetry (DSC), wide angle X-ray scattering (WAXS), Fourier transform infrared (FT-IR) spectroscopy, and tapping mode atomic force microscopy (TMAFM). These low-crystallinity polypropylenes, when crystallized isothermally from the melt, exhibit morphologies reminiscent of classical semi-crystalline polymers. The presence of lamellae, cross-hatching, hedrites, and spherulites was revealed by high resolution TM-AFM. These elastomeric polypropylenes can be fractionated into components of different average tacticities and crystallinities, but similar molecular mass. The analysis of the morphologies of all of the fractions revealed both large hierarchical structures and cross-hatching typical of the {alpha}-modification of crystalline isotactic polypropylene for all but the lowest crystalline ether soluble fraction. Evidence for high-melting crystals in all of the fractions are most consistent with a stereoblock microstructure of atactic and isotactic sequences.

Pople, John A

2002-08-06

104

Does UV disinfection compromise sutures? An evaluation of tissue response and suture retention in salmon surgically implanted with transmitters  

Energy Technology Data Exchange (ETDEWEB)

Ultraviolet radiation (UVR) can be used as a tool to disinfect surgery tools used for implanting transmitters into fish. However, the use of UVR could possibly degrade monofilament suture material used to close surgical incisions. This research examined the effect of UVR on monofilament sutures to determine if they were compromised and negatively influenced tag and suture retention, incision openness, or tissue reaction. Eighty juvenile Chinook salmon Oncorhynchus tshawytscha were surgically implanted with an acoustic transmitter and a passive integrated transponder. The incision was closed with a single stitch of either a suture exposed to 20 doses of UV radiation (5 minute duration per dose) or a new, sterile suture. Fish were then held for 28 d and examined under a microscope at day 7, 14, 21 and 28 for incision openness, ulceration, redness, and the presence of water mold. There was no significant difference between treatments for incision openness, redness, ulceration or the presence of water mold on any examination day. On day 28 post-surgery, there were no lost sutures; however, 2 fish lost their transmitters (one from each treatment). The results of this study do not show any differences in negative influences such as tissue response, suture retention or tag retention between a new sterile suture and a suture disinfected with UVR.

Walker, Ricardo W.; Brown, Richard S.; Deters, Katherine A.; Eppard, M. B.; Cooke, Steven J.

2013-10-01

105

Surgical device for supporting corneal suturing  

Science.gov (United States)

A system for ophthalmic surgery support has been developed in order to minimize the residual astigmatism due to the induced irregular shape of the cornea by corneal suture. The system projects 36 light spots, from LEDs, displayed in a precise circle at the lachrymal film of the examined cornea. The displacement, the size and deformation of the reflected image of these light spots are analyzed providing the keratometry and the circularity of the suture. Measurements in the range of 32D - 55D (up to 23D of astigmatism are possible to be obtained) and a self-calibration system has been designed in order to keep the system calibrated. Steel precision spheres have been submitted to the system and the results show 99% of correlation with the fabricant's nominal values. The system has been tested in 13 persons in order to evaluate its clinical applicability and has been compared to a commercial keratometer Topcon OM-4. The correlation factors are 0,92 for the astigmatism and 0.99 for the associated axis. The system indicates that the surgeon should achieve circularity >=98% in order to do not induce astigmatisms over 3D.

Ventura, Liliane; Oliveira, Gunter C. D.; De Groote, Jean-Jacques; Sousa, Sidney J. F.; Saia, Paula

2009-02-01

106

Geophysical exploration of the Kalahari Suture Zone  

Science.gov (United States)

Fancamp Resources Limited of Montreal, Canada, commenced exploration of the Kalahari Suture Zone in southwest Botswana in 1996, following the interpretation of airborne magnetic surveys covering 400 km of strike along the Kalahari Suture Zone. Initial focus was on mafic/ultramafic intrusions associated with the Tshane Complex as potential targets for Cu?Ni?PGM mineralization, but these targets are now considered to be too deeply buried (> 700 m) to be of economic significance at this time. The exploration focus has been redirected to several prospective large coincident magnetic/gravity anomalies. These are considered prospective targets for Olympic Dam-type Cu?Co mineralisation associated with alkaline intrusive complexes, and/or Ni?Cu?Co?PGM mineralisation associated with basic intrusive complexes. The two most important and prospective targets are the so-called 'Great Red Spot' and Tsetseng Complex. Additional ground geophysical surveys and deep drilling are planned for the next phase of exploration. These large targets are of high priority and represent tremendous potential for mineral development in the sparsely populated area of western Botswana.

Brett, J. S.; Mason, R.; Smith, P. H.

2000-04-01

107

Reacción tisular a materiales de sutura no absorbibles en piel de equinos / Tissue reaction to nonabsorbable suture materials in horse skin  

Scientific Electronic Library Online (English)

Full Text Available Se evaluó clínica e histológicamente el grado de reacción tisular frente a cuatro materiales de sutura no absorbibles (lino, nylon, caprolactam polimerizado y polipropileno), implantados en la piel de 8 equinos. Se determinó clínicamente el edema provocado y la ausencia o presencia de exudado a los [...] 5 y 10 días de haber sido implantados los materiales de sutura, además al 10º día se realizó una biopsia para determinar histológicamente el grado de reacción tisular. Los resultados obtenidos mostraron que el lino causó un mayor edema al día 5, mientras que al día 10 el nylon y caprolactam provocaron un menor de edema. Con respecto a la presencia o ausencia de exudado, al día 5 la sutura de nylon fue la única que no presentó exudado en ninguno de los 8 ejemplares, sin embargo, al día 10, salvo un ejemplar que presentó exudado en todos los materiales, el nylon, caprolactam y polipropileno no presentaron exudado. En cuanto a la evaluación histológica tanto el nylon como el caprolactam mostraron menor grado de reacción tisular. En conclusión, el lino resultó tener el mayor grado de reacción tisular durante el presente estudio, y el nylon si bien es similar al caprolactam y polipropileno respecto a la reacción tisular, causó una menor cantidad de equinos con presencia de exudado que los otros materiales utilizados. Abstract in english The degree of tissue reaction of 4 nonabsorbable suture materials (linen, nylon, polymerized caprolactum and polypropylene) implanted into health skin of 8 horses was clinically and histologically evaluated. Cutaneous oedema and absence or presence of the exudation were clinically evaluated 5 and 10 [...] days following suture material implantation. Biopsies were taken to histologically evaluate tissue reaction at 10 days. The results obtained showed that linen caused more oedema by the 5th day, whereas the nylon and caprolactum had less oedema on the 10th day. With respect to the presence or absence of exudation, nylon was the only material which did not show exudation by the 5th day in any of the 8 samples, but on the 10th day, neither the nylon, caprolactum or polypropylene showed exudation, except one horse that showed exudation for all suture materials. The histological evaluation showed that nylon and caprolactum caused less tissue reaction. In conclusion, linen was found to have a higher degree of tissue reaction in the present study, and nylon although similar to caprolactum and polypropylene in terms of tissue reaction, caused less cases of exudate than the other suture materials used.

F, Maldonado; L, Muñoz; M, Quezada; M, Briones; P, Urrutia.

108

Reacción tisular a materiales de sutura no absorbibles en piel de equinos Tissue reaction to nonabsorbable suture materials in horse skin  

Directory of Open Access Journals (Sweden)

Full Text Available Se evaluó clínica e histológicamente el grado de reacción tisular frente a cuatro materiales de sutura no absorbibles (lino, nylon, caprolactam polimerizado y polipropileno, implantados en la piel de 8 equinos. Se determinó clínicamente el edema provocado y la ausencia o presencia de exudado a los 5 y 10 días de haber sido implantados los materiales de sutura, además al 10º día se realizó una biopsia para determinar histológicamente el grado de reacción tisular. Los resultados obtenidos mostraron que el lino causó un mayor edema al día 5, mientras que al día 10 el nylon y caprolactam provocaron un menor de edema. Con respecto a la presencia o ausencia de exudado, al día 5 la sutura de nylon fue la única que no presentó exudado en ninguno de los 8 ejemplares, sin embargo, al día 10, salvo un ejemplar que presentó exudado en todos los materiales, el nylon, caprolactam y polipropileno no presentaron exudado. En cuanto a la evaluación histológica tanto el nylon como el caprolactam mostraron menor grado de reacción tisular. En conclusión, el lino resultó tener el mayor grado de reacción tisular durante el presente estudio, y el nylon si bien es similar al caprolactam y polipropileno respecto a la reacción tisular, causó una menor cantidad de equinos con presencia de exudado que los otros materiales utilizados.The degree of tissue reaction of 4 nonabsorbable suture materials (linen, nylon, polymerized caprolactum and polypropylene implanted into health skin of 8 horses was clinically and histologically evaluated. Cutaneous oedema and absence or presence of the exudation were clinically evaluated 5 and 10 days following suture material implantation. Biopsies were taken to histologically evaluate tissue reaction at 10 days. The results obtained showed that linen caused more oedema by the 5th day, whereas the nylon and caprolactum had less oedema on the 10th day. With respect to the presence or absence of exudation, nylon was the only material which did not show exudation by the 5th day in any of the 8 samples, but on the 10th day, neither the nylon, caprolactum or polypropylene showed exudation, except one horse that showed exudation for all suture materials. The histological evaluation showed that nylon and caprolactum caused less tissue reaction. In conclusion, linen was found to have a higher degree of tissue reaction in the present study, and nylon although similar to caprolactum and polypropylene in terms of tissue reaction, caused less cases of exudate than the other suture materials used.

F Maldonado

2006-01-01

109

Suture granuloma simulating lung neoplasm occurring after segmentectomy.  

OpenAIRE

A suture granuloma was resected which developed after segmentectomy of a squamous cell carcinoma of the lung and radiologically mimicked a neoplasm. This report emphasises that although the appearance of the lesion may be typical for malignancy, the possibility of a benign suture granuloma should be considered, especially if the lesion appears shortly after surgery.

Fink, G.; Herskovitz, P.; Nili, M.; Hadar, H.; Rothem, A.; Spitzer, S. A.

1993-01-01

110

A biomechanical comparison of suture constructs used for coracoclavicular fixation.  

Science.gov (United States)

There is no consensus regarding surgical treatment for severely dislocated acromioclavicular joints. Although many treatments are suture-based, the suture materials and resulting suture-bone constructs have been subjected to limited systematic evaluation. This study identifies the strongest and least deforming suture construct among those commonly used for such repairs. Each suture-based repair was tested on a simulated clavicle and coracoid process with the skeletal components distracted until the suture failed to obtain tensile strength. Additional groups of sutures were subjected to cyclic loading to determine resistance to deformation. Panacryl braid had significantly greater tensile strength than all other constructs: Polydioxanone (PDS) braid, Mersilene tape, and Ethibond #5. Deformation after cyclic loading of Panacryl braid, PDS braid, and two strands of Mersilene tape was significantly less than that of the other constructs. A bioabsorbable suture loop, such as Panacryl, can act as a temporary internal splint, maintaining acromioclavicular joint reduction long enough for ligamentous healing during rehabilitation, and can avoid complications associated with permanent fixation materials. Panacryl braid deserves serious consideration for coracoclavicular fixation because of its strength, resistance to deformation, and bioabsorbable properties. PMID:14577722

Wickham, M Quinn; Wyland, Douglas J; Glisson, Richard R; Speer, Kevin P

2003-01-01

111

High-resolution sonography of the abnormal cranial suture  

International Nuclear Information System (INIS)

Objective. The purpose of this investigation is to elucidate the sonographic features of abnormal major cranial sutures. Materials and methods. Eight excised synostosed suture specimens were evaluated. The high-resolution sonographic appearance was correlated with the histological section, plain radiographs, CT and MRI. Diastatic and molded sutures were also evaluated with sonography and compared with the normal cranial suture appearance. Results. Synostosed sutures demonstrated one or more of the following features: (a) loss of echo-poor fibrous gap between bony plates (five sagittal and coronal synostoses); (b) irregular thickened inner sutural margin (three lambdoid synostoses); (c) loss of bevelled edge (one lambdoid synostosis); (d) asymmetric anterior fontanelle (one coronal synostosis). Cranial molding results in an overlap of echogenic bony plates. Sutural width (the distance between bony plates) is increased in cases of elevated intracranial pressure. Conclusion. Sonography is an inexpensive, radiation-free modality which can confirm synostosis versus molding versus an underlying intracranial lesion as a cause of plagiocephaly. The high-resolution sonographic images also provide a relatively easy means to assess sutural width and may provide information in regard to increased intracranial pressure. (orig.)

112

High-resolution sonography of the abnormal cranial suture  

Energy Technology Data Exchange (ETDEWEB)

Objective. The purpose of this investigation is to elucidate the sonographic features of abnormal major cranial sutures. Materials and methods. Eight excised synostosed suture specimens were evaluated. The high-resolution sonographic appearance was correlated with the histological section, plain radiographs, CT and MRI. Diastatic and molded sutures were also evaluated with sonography and compared with the normal cranial suture appearance. Results. Synostosed sutures demonstrated one or more of the following features: (a) loss of echo-poor fibrous gap between bony plates (five sagittal and coronal synostoses); (b) irregular thickened inner sutural margin (three lambdoid synostoses); (c) loss of bevelled edge (one lambdoid synostosis); (d) asymmetric anterior fontanelle (one coronal synostosis). Cranial molding results in an overlap of echogenic bony plates. Sutural width (the distance between bony plates) is increased in cases of elevated intracranial pressure. Conclusion. Sonography is an inexpensive, radiation-free modality which can confirm synostosis versus molding versus an underlying intracranial lesion as a cause of plagiocephaly. The high-resolution sonographic images also provide a relatively easy means to assess sutural width and may provide information in regard to increased intracranial pressure. (orig.) With 5 figs., 12 refs.

Soboleski, D.; Mussari, B.; McCloskey, D.; Sauerbrei, E.; Espinosa, F.; Fletcher, A. [Department of Diagnostic Radiology, Kingston General Hospital, 76 Stuart St., Kingston, Ontario K7L 2V7 (Canada)

1998-02-01

113

STUDY ON METOPIC SUTURES IN SOUTH INDIAN SKULLS  

Directory of Open Access Journals (Sweden)

Full Text Available The midline suture between two halves of the developing frontal bone usually fuses by infancy or early childhood. In some cases it may persist in complete or incomplete metopic sutures with variable morphology.  The incidence and morphological pattern of these sutures were being studied using 120 skulls from the Department of Anatomy, Yenepoya Medical College among which 4 skulls (3.33% showed complete metopism, 98 skulls (81.66% showed presence of incomplete metopic suture whereas 18 skulls (15% showed total absence of metopic suture. Of the skulls that showed incomplete metopic sutures, 96 (97.95% were on the anterior 1/3 starting from nasion extending over glabella, 2 (2.04% were on the middle 1/3. No suture could be found on the posterior 1/3.The morphological pattern was studied on the sutures present on anterior 1/3 of the skull. Among these, 26 (26.53% were linear, 13 (13.26% were double linear, 13 (13.26% were V shaped, 12 (12.24% were U shaped, 7 (7.14% were H shaped, 5 (5.1% were Y shaped. 2 (2.04% showed inverted-U pattern whereas 18 (18.36% showed side to side excursion patterns. The data obtained in this study will be useful in the field of Anatomy, Forensic medicine, radio diagnosis and neurosurgery.

Rani Nallathamby*, Ramakrishna Avadhani Sivarama CH, Boban Babu and Meera Jacob

2013-07-01

114

A comparison of CO2 laser-assisted venous anastomoses and conventional suture techniques: patency, aneurysm formation, and histologic differences.  

Science.gov (United States)

The expected patency and the potential complications of CO2 laser-welded end-to-end venous anastomoses have not been well established despite increasing clinical interest in the subject. To further study this relatively new technique we used the internal jugular veins (1.0 to 1.4 mm diameter) of 15 New Zealand White rabbits weighing 2.5 to 3.5 kg. On one randomly selected side, a laser-welded end-to-end anastomosis was performed in all animals by placing three equidistant stay sutures followed by welding the vein edges with a CO2 laser (spot size of 0.27 mm, power of 100 mW, and power density of 175 W/cm2). On the contralateral side, the vein was anastomosed with interrupted 10-0 nylon sutures in 10 animals, and in the remaining five animals a continuous 10-0 nylon suture technique was used. All anastomoses were surgically assessed at 30 days after operation. A significantly lower 30-day patency rate (p less than 0.05, Fisher's Exact Test) was found in anastomoses constructed by use of the continuous technique (20%) compared with either interrupted (90%) or the laser-assisted technique (87%). No significant difference was observed in 30-day patency between laser-assisted and conventional interrupted anastomoses. Anastomoses performed with the continuous and the laser-assisted technique required 12.5 +/- 1.3 and 12.9 +/- 3.0 minutes, respectively, whereas those constructed with interrupted technique required 19.1 +/- 4.5 minutes (p less than 0.05, Student-Neuman-Keuls' Test). No evidence of false or true aneurysm was noted in any of the animals. Histologic evaluation of laser-assisted anastomoses demonstrated early full-thickness coagulation necrosis of the wall with reendothelialization by 7 days and complete healing by 30 days after the procedure. Conventional anastomoses showed reendothelialization and minimal necrosis near the sutures at 7 days, but healing was complete by 30 days after the procedure. The patency rate of vein anastomoses performed with the CO2 laser is excellent and superior to the one obtained with continuous sutures, and except for less operating time, the former technique does not appear to offer any significant advantage over the conventional interrupted suture technique for small vein anastomosis in this animal model up to 1 month of follow-up. PMID:1942367

Gennaro, M; Ascer, E; Mohan, C; Wang, S

1991-11-01

115

Radiation stability of polypropylene/lead zirconate composites  

International Nuclear Information System (INIS)

The effects of PbZrO3 filler in polypropylene were studied by isothermal and nonisothermal chemiluminescence and FT-IR spectroscopy after ?(137Cs)-irradiation at 20, 50, 100 and 250 kGy relative to neat material. For the two filler concentrations (2 and 5 wt%) the improvement in radiation stability can be noticed. The increase in the filler concentration stabilizes polypropylene matrix, whose oxidation rate decreases sharply even at 250 kGy. The interaction of polypropylene matrix with filler is discussed based on the adsorption of free radicals on zirconate particles and the electronic coupling of radiolysis intermediates and filler cations. - Highlights: • Polypropylene is more stable under gamma irradiation in the presence of lead zirconate. • Intermediate temperatures around 100 °C reveal a partial oxidation of polypropylene substrate. • Radiation stability of polypropylene compounded with lead zirconate is remarkable, leading to different applications in the manufacture of membranes

116

78 FR 78748 - 2,5-Furandione, polymer With ethenylbenzene, Reaction Products With polyethylene-polypropylene...  

Science.gov (United States)

...Reaction Products With polyethylene-polypropylene glycol 2-aminopropyl Me ether; Tolerance...reaction products with polyethylene-polypropylene glycol 2-aminopropyl Me ether; minimum...reaction products with polyethylene-polypropylene glycol 2-aminopropyl Me ether...

2013-12-27

117

21 CFR 870.3470 - Intracardiac patch or pledget made of polypropylene, polyethylene terephthalate, or...  

Science.gov (United States)

...Intracardiac patch or pledget made of polypropylene, polyethylene terephthalate, or polytetrafluoroethylene...Intracardiac patch or pledget made of polypropylene, polyethylene terephthalate, or polytetrafluoroethylene...intracardiac patch or pledget made of polypropylene, polyethylene terephthalate,...

2010-04-01

118

Materiales de sutura quirúrgico / Surgical suture materials  

Scientific Electronic Library Online (English)

Full Text Available Se realizó una revisión bibliográfica sobre el tema Materiales de sutura quirúrgica, tanto nacional como internacionalmente, tratando de encontrar la información más actualizada posible, tomando como base un trabajo publicado en una revista nacional en el año 1990 y una revisión bibliográfica nuestr [...] a presentada en el hospital Amalia Simoni en 1995. Se revisaron los materiales informativos de algunas casas comerciales y a partir de aquí, se expusieron las clasificaciones conocidas con los productos que la conforman y se ofrecieron las características del producto comercial y del fabricante. Se señalaron las ventajas de los materiales de sutura de origen sintético sobre los naturales que van siendo desplazados en su utilización y preferencia. Existe el interés de ayudar a mejorar el conocimiento sobre este tema a los profesionales de la salud, personal paramédico y en formación al igual que a médicos veterinarios. Abstract in english A bibliographical review on the topic of surgical suture material, so much national as internationally, trying to find the most up-to-date possible information, taking as base a work published in a national magazine in the year 1990 and a bibliographical review of ours presented in Amalia Simoni hos [...] pital in 1995. The informative materials of some business houses are reviewed and starting from here, the well-known classifications are exposed with the products that compose it and offering the characteristics of the commercial product and the manufacturer. The advantages of the suture materials of synthetic origin are pointed out on the natural ones that are displaced in their use and preference. It encourages us the interest of helping to improve the knowledge on this topic to the health professionals and in formation, paramedic personnel as well as to veterinary doctors.

Karina, Armas Moredo; Bárbaro A, Armas Pérez; Leandro, Segura Pujal; Joaquín, Márquez Hernández; Katia, Armas Moredo.

2009-10-01

119

Compression of polypropylene across a wide range of strain rates  

OpenAIRE

Three grades of polypropylene were tested in uniaxial compression at room temperature, across a wide range of strain rate: 10-4 s-1 to 104 s-1. One grade is a conventional polypropylene homopolymer. The two other grades are the polypropylene forming the matrix phase of a continuous glass fibre-reinforced thermoplastic composite prepreg, with and without blending with a carbon-black master batch. Tests at the highest strain rates were performed using a compression split Hopkinson pressure bar....

Okereke, Mi; Buckley, Cp; Siviour, Cr

2012-01-01

120

Radiation effects on polypropylene/polybutylene blends  

International Nuclear Information System (INIS)

Polymer blends of polypropylene and polybutylene have been found to exhibit substantial maintenance of structural integrity after exposure to ionizing radiation. This radiation resistance has been found to be related to processing conditions and the resulting morphology of the blend. This article discusses (a) the processing conditions and the resulting mechanical properties after irradiation and (b) the role of morphology in this unexpected blend property

121

Polypropylene : Morphology, defects and electrical breakdown  

OpenAIRE

Crystal structure, morphology and crystallization kinetics of melt-crystallized polypropylene and poly(propylene-stat-ethylene) fractions with 2.7 to 11.0 mol% of ethylene were studied by differential scanning calorimeter, wide- and small-angle X-ray scattering, polarized light microscopy, transmission electron microscopy and infrared spectroscopy. With increasing ethylene content the poly(propylene-stat-ethylene) fractions showed unchanged crystallinity, increased unit cell volume and consta...

Laihonen, Sari J.

2005-01-01

122

Residual stress distribution in extruded polypropylene pipes.  

Czech Academy of Sciences Publication Activity Database

Ro?. 2014, ?. 40 (2014), s. 88-98. ISSN 0142-9418 R&D Projects: GA ?R(CZ) GAP108/12/1560 Institutional support: RVO:68081723 Keywords : polypropylene * extruded polymer pipe * residual stress * curved beam methodology * numerical simulations Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 1.816, year: 2013 http://www.sciencedirect.com/science/article/pii/S0142941814001809

Poduška, Jan; Ku?era, J.; Huta?, Pavel; Šev?ík, Martin; K?ivánek, J.; Sadílek, J.; Náhlík, Luboš

2014-01-01

123

Validation of material model for polypropylene (PP)  

OpenAIRE

A hyperelastic-viscoplastic material model intended for thermoplastics has been developed by SIMLab at NTNU. This model formed the basis of the thesis, where a material model for the polymer polypropylene was calibrated and validated. Four rounds of material testing were carried out. Tension and compression tests formed the basis for a calibration of the material model. Two different component tests were used for validation; stretching of a plate with a hole and plate impact tests.The calibra...

Sælen, Kristin

2012-01-01

124

Polypropylene matrix composites reinforced with coconut fibers  

OpenAIRE

Polypropylene matrix composites reinforced with treated coconut fibers were produced. Fibers chemically treated (alkalization-CCUV samples) or mechanically treated (ultrasonic shockwave-CMUV samples) were dried using UV radiation. The goal was to combine low cost and eco-friendly treatments to improve fiber-matrix adhesion. Composite samples containing up to 20 vol. (%) of untreated and treated coconut fibers were taken from boxes fabricated by injection molding. Water absorption and mechanic...

Maria Virginia Gelfuso; Pedro Vieira Gurgel da Silva; Daniel Thomazini

2011-01-01

125

Highly Filled Polypropylene Rubber Wood Flour Composites  

Directory of Open Access Journals (Sweden)

Full Text Available In this research, polypropylene composites filled with Hevea Brasilliensis wood flour at filler content up to 60wt% were prepared and investigated in order to determine the effects of polymer melt flow rate (MFR, number of reprocessing times, filler size, and filler content on thermal and mechanical properties. The results reveal that the composites of polypropylene with higher melt flow rate (lower viscosity provided greater values of flexural and tensile properties. The study additionally exhibits the recyclability potential without losing mechanical properties. Furthermore, both flexural and tensile modulus increased, while both flexural and tensile strength decreased with increasing wood flour contents. In addition, the average particle size of wood flour that was suitable for improving the mechanical properties was approximately 200-300 um. In the last section of the research, the effects of maleic anhydride grafted polypropylene (MAPP coupling agent were investigated. It is worth noting that, the flexural strength and tensile strength of highly filled composites with MAPP at 5wt% (based on wood flour were approximately 110 % and 87% higher than those of the composites without MAPP, respectively. In the presence of coupling agent, the enhancement of interfacial adhesion was analyzed using scanning electron microscope (SEM.

Sunan Tiptipakorn

2011-04-01

126

Effects of ?-ray irradiation on polypropylene  

International Nuclear Information System (INIS)

The authors have found that the G-value of free radical formation by ?-ray irradiation on polyolefin depends on the higher order structure. Therefore, efforts were made to separately observe the changes in the amorphous and crystalline phases by ?-irradiation using visco-elastic measurement, differential scanning calorimetry, and X-ray method. Isotactic polypropylene was chosen as the material. The drawn and bulk samples were irradiated by ?-ray of 60Co at room temperature. Wide angle X-ray diffraction was measured to estimate the lattice constant and the halfwidth of the diffraction peak. The results obtained were discussed for the change of dynamic loss modulus E'' with temperature for the bulk samples, irradiation effects on the viscoelastic behavior of the drawn samples, and thermograms for the undrawn and drawn samples. Polypropylene has been classified as a cross-linking type polymer. In the amorphous phase, cross-linking occurs to increase the temperature location of ?a absorption. While it was found that crystal imperfection was introduced by irradiation from the illustrated facts. This crystal imperfection can be introduced by two mechanisms, (1) cross-linking formation between adjacent chains, and (2) chain scission to form chain ends. The mechanism (2) seems to be responsible for the crystal imperfection resulting in decrease of maximum temperature in polypropylene. (Wakatsuki, Y.)

127

High strain rate behaviour of polypropylene microfoams  

Directory of Open Access Journals (Sweden)

Full Text Available Microcellular materials such as polypropylene foams are often used in protective applications and passive safety for packaging (electronic components, aeronautical structures, food, etc. or personal safety (helmets, knee-pads, etc.. In such applications the foams which are used are often designed to absorb the maximum energy and are generally subjected to severe loadings involving high strain rates. The manufacture process to obtain polymeric microcellular foams is based on the polymer saturation with a supercritical gas, at high temperature and pressure. This method presents several advantages over the conventional injection moulding techniques which make it industrially feasible. However, the effect of processing conditions such as blowing agent, concentration and microfoaming time and/or temperature on the microstructure of the resulting microcellular polymer (density, cell size and geometry is not yet set up. The compressive mechanical behaviour of several microcellular polypropylene foams has been investigated over a wide range of strain rates (0.001 to 3000?s?1 in order to show the effects of the processing parameters and strain rate on the mechanical properties. High strain rate tests were performed using a Split Hopkinson Pressure Bar apparatus (SHPB. Polypropylene and polyethylene-ethylene block copolymer foams of various densities were considered.

Martínez A.B.

2012-08-01

128

Cyclic viscoelastoplasticity of polypropylene/nanoclay composites  

DEFF Research Database (Denmark)

Observations are reported on isotactic polypropylene/organically modified nanoclay hybrids with concentrations of filler ranging from 0 to 5 wt.% in cyclic tensile tests with a stress–controlled program (oscillations between various maximum stresses and the zero minimum stress). A pronounced effect of nanofiller is demonstrated: reinforcement with 2 wt.% of clay results in strong reduction of maximum and minimum strains per cycle and growth of number of cycles to failure compared with neat polypropylene. To rationalize these findings, a constitutive model is developed in cyclic viscoelasticity and viscoplasticity of polymer nanocomposites. Adjustable parameters in the stress–strain relations are found by fitting experimental data. The model correctly describes the growth of the ratcheting strain and shows that fatigue failure is driven by a pronounced increase in plastic strain in the crystalline phase. To assess the influence of loading conditions on the changes in the material parameters, experimental data on polypropylene are studied in cyclic tests with a strain–controlled program (oscillations between fixed maximum and minimum strains) and a mixed program (oscillations between various maximum strains and the zero minimum stress). Numerical simulation confirms the ability of the model to predict the evolution of stress–strain diagrams with the number of cycles.

Drozdov, A.; Christiansen, Jesper de Claville

2012-01-01

129

High strain rate behaviour of polypropylene microfoams  

Science.gov (United States)

Microcellular materials such as polypropylene foams are often used in protective applications and passive safety for packaging (electronic components, aeronautical structures, food, etc.) or personal safety (helmets, knee-pads, etc.). In such applications the foams which are used are often designed to absorb the maximum energy and are generally subjected to severe loadings involving high strain rates. The manufacture process to obtain polymeric microcellular foams is based on the polymer saturation with a supercritical gas, at high temperature and pressure. This method presents several advantages over the conventional injection moulding techniques which make it industrially feasible. However, the effect of processing conditions such as blowing agent, concentration and microfoaming time and/or temperature on the microstructure of the resulting microcellular polymer (density, cell size and geometry) is not yet set up. The compressive mechanical behaviour of several microcellular polypropylene foams has been investigated over a wide range of strain rates (0.001 to 3000 s-1) in order to show the effects of the processing parameters and strain rate on the mechanical properties. High strain rate tests were performed using a Split Hopkinson Pressure Bar apparatus (SHPB). Polypropylene and polyethylene-ethylene block copolymer foams of various densities were considered.

Gómez-del Río, T.; Garrido, M. A.; Rodríguez, J.; Arencón, D.; Martínez, A. B.

2012-08-01

130

Influence of the elastomeric polypropylene addition on the properties of commercial metallocenic polypropylene  

Directory of Open Access Journals (Sweden)

Full Text Available Polypropylene with special properties can be obtained by metallocenic catalysts. These catalytic systems represent the beginning of a new age in polyolefins technology. In this work, the influence of the addition of a syndiotactic polypropylene (s-PP on the processability and mechanical properties of a commercial isotactic polypropylene (i-PP obtained by metallocenic catalysts was evaluated. Increasing addition of s-PP promoted better processability, with an increase in the impact strength and a decrease in the stress at break. A reduction of the crystallinity in the polymeric blends was verified. The more significant influence of the s-PP addition was observed for the mi-PP, compared to the ZNi-PP.

Marques Maria de Fátima V.

2001-01-01

131

U10.0 Undulator conceptual design report  

International Nuclear Information System (INIS)

The U10.0 Undulator described here is a 43 period, 10 cm period, 4.5 meter long insertion device. Designed for the Advanced Light Source (ALS) storage ring at the Lawrence Berkeley Laboratory. This insertion device will provide high brightness, quasi-monochromatic radiation in the 5-950 eV energy range. This conceptual design report includes sections on: parameter development, spectral performance, and accelerator requirements, physics specifications and the detailed conceptual design of the magnetic structure, the support/drive systems, the insertion device control system, the vacuum system, and installation for the U10.0 Undulator

132

U10.0 Undulator conceptual design report  

Energy Technology Data Exchange (ETDEWEB)

The U10.0 Undulator described here is a 43 period, 10 cm period, 4.5 meter long insertion device. Designed for the Advanced Light Source (ALS) storage ring at the Lawrence Berkeley Laboratory. This insertion device will provide high brightness, quasi-monochromatic radiation in the 5-950 eV energy range. This conceptual design report includes sections on: parameter development, spectral performance, and accelerator requirements, physics specifications and the detailed conceptual design of the magnetic structure, the support/drive systems, the insertion device control system, the vacuum system, and installation for the U10.0 Undulator.

Hoyer, E.

1994-06-01

133

Suture-related pseudoinfection after total hip arthroplasty.  

Science.gov (United States)

Absorbable sutures are widely used for wound closure after total hip replacement. Here we present two cases of suture-related foreign-body reaction that perfectly mimicked a periprosthetic joint infection, with sterile abscess formation and physical and laboratory signs of inflammation acutely presenting 7-8 weeks after surgery, at the time of suture absorption. Both recurred with analogous timing after irrigation and debridement, likely due to re-using the same suture material. Multiple negative microbiological samples and positive histological samples showing a foreign-body reaction are the fundamental steps towards the diagnosis of a suture-related pseudoinfection (SRPI). Only three other cases have been reported to date, but the recurrence, together with the self-healing course after relapse, represents a completely novel feature and possibly the strongest demonstration of the supposed aetiopathogenesis. The knowledge of this possible complication leads to some clinical implications: all potential periprosthetic joint infections should routinely undergo not only microbiological but also histological sampling; caution should be used when recommending prosthesis exchange for potential infections occurring in the time range of suture absorption; lastly, if SRPI is suspected, a suture with low propensity to induce foreign-body reactions should be chosen after irrigation and debridement and the volume of absorbable material left in the wound should be as small as possible. PMID:24916148

Pierannunzii, Luca; Fossali, Andrea; De Lucia, Orazio; Guarino, Arturo

2015-03-01

134

Gene expression profiling in the rat cranial suture.  

Science.gov (United States)

Although many theories have attempted to explain the etiopathogenesis of premature cranial suture fusion, which results in craniosynostosis, recent studies have focused on the role of growth factors and receptors. Using a well-established model of cranial suture biology, the authors developed a novel approach to quantitatively analyze the gene expression profiles of candidate cranial suture growth factors and their receptors. We collected suture mesenchyme and adjacent osteogenic fronts from Sprague-Dawley rats at postnatal days 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, and 35. RNA was extracted from posterior frontal (PF) and sagittal (SAG) sutures, and reverse transcription-polymerase chain reaction (RT-PCR) was performed for cranial suture candidate cytokines BMP2, BMP3, BMP4, FGF-2, FGFR1, FGFR2, FGFR4, TGF-betaRI, TGF-betaRII, and TGF-betaRIII. The authors confirmed quantitative RT-PCR results with Southern and dot blot analyses. Suture growth factor and receptor expression levels changed significantly with time. Expression levels decreased toward baseline in the SAG suture by day 35. There was a marked difference in FGFR1, FGF-2, TGF-betaRI, and TGF-betaRII expression levels when comparing the fusing PF and nonfusing SAG sutures. Although FGF-2 ligand expression was low, FGF receptor 1 (FGFR1) levels were markedly elevated with a bimodal expression pattern in both PF and SAG similar to that of BMP2, BMP3, and BMP4. Although there were statistically significant differences in TGF-betaRI and TGF-betaRII expression in the PF and SAG sutures, TGF-betaRIII levels were unchanged. The authors report a novel approach to cranial suture growth factor/receptor profiling and confirm their results with standard analytic tools. The data confirm, quantify, and extend the results of previously published studies. By quantifying the gene expression profiles of normal cranial suture biology, we may begin to understand the aberrant growth factor cascades of craniosynostosis and devise targeted therapeutic interventions that can alter the course of this malady. PMID:15915100

Law, Clarice S; Warren, Stephen M; Mehrara, Babak J; Ting, Kang

2005-05-01

135

Rhinoplasty: open tip suture techniques: a 25-year experience.  

Science.gov (United States)

Based on a 25-year experience, the author considers open tip suture techniques to be the best method of achieving consistent and reproducible tip changes that can please patients with a wide variety of tip deformities. The described technique consists of selecting the ideal combination of the following six sutures: (1) columellar strut and suture, (2) domal creation, (3) interdomal, (4) domal equalization, (5) tip position, and (6) lateral crural convexity. If additional definition is required, then tip refinement grafts can be added to accommodate thicker skin or lateral crura abnormalities. PMID:21404163

Daniel, Rollin K

2011-04-01

136

Left atrial appendage occlusion by invagination and double suture technique.  

Science.gov (United States)

Left atrial appendage (LAA) plays a crucial role as a source of atrial thrombus in patients with atrial fibrillation (AF). Thus, the need to close LAA becomes evident in patients with AF who undergo concomitant mitral valve surgery. Unfortunately, it has been reported a high rate of unsuccessful LAA occlusion, regardless of the technique employed.We propose a safe and simple method for LAA occlusion consisting in invagination of the appendage into the left atrium, followed by two sutures (purse string suture around the base of the LAA and a reinforce running suture). PMID:21684756

Hernandez-Estefania, Rafael; Levy Praschker, Beltran; Bastarrika, Gorka; Rabago, Gregorio

2012-01-01

137

Absorption and Tensility of Bioactive Sutures Prepared for Cell Transplantation  

Directory of Open Access Journals (Sweden)

Full Text Available Biodegradable scaffolds are widely used to transplant stem cells into various tissues. Recent studies showed that living stem cells can be attached to the surface of absorbable sutures in vitro. Soaking the absorbable material polyglactin in a cell culture medium and thereby creating a stem cell biofilm on its surface may initiate the absorption process even before implantation; therefore, the physicochemical properties of the suture may be compromised in vivo. We found that pre-incubation of sutures in cell culture media in vitro results in tensile strength reduction and faster suture absorption in a rat model of muscle injury. Shorter incubation times of up to 48 h do not influence absorption or tensility; therefore, it is advisable to limit incubation times to two days for polyglactin-based cell delivery protocols.

Zsombor Lacza

2013-02-01

138

Explosive spalling of concrete, the mitigating effect of Polypropylene Fibres  

DEFF Research Database (Denmark)

This paper briefly describes the main results of a recent investigation on the influence of polypropylene fibres and restraint on the susceptibility of concrete to explosive spalling at high temperatures. The results suggest that polypropylene fibres may prevent spalling in both unstrained and restrained structures.

SØrensen, Lars SchiØtt Technical University of Denmark,

2003-01-01

139

Ophiolite belts in the sw-iberian variscan suture  

OpenAIRE

The SW-Iberia Variscan suture is the boundary between the Iberian (IT) and the South-Portuguese (SPT) Terranes, materializing the closure of Rheic and related oceans by northeast ward subduction of the SPT under the IT. The western segment of this suture displays imbrications of various units belonging to: (1) Neoproterozoic - Lower Palaeozoic Ossa Morena Zone (OMZ) relative autochthonous (locally covered by Lower-Middle Devonian limestones and shales); and (2) allochthonous complexes. The la...

Ribeiro, Anto?nio; Pedro, Jorge; Tassinari, Colombo; Munha?, Jose?; Arau?jo, Alexandre; Fonseca, Paulo; Mateus, Anto?nio; Gil, Pedro

2008-01-01

140

Strength of sliding knots in multifilament resorbable suture materials  

OpenAIRE

Experimental laboratory study was made to test the knot integrity of identical, non-identical and parallel sliding knots, with three and five throws, made with synthetic resorbable multifilament suture materials. The knots were made with Novosyn (polyglactin 612), Safil (polyglycolic acid), Vicryl (polyglactin 612) and Vicryl plus (polyglactin 910 + triclosan), all with suture size: 3-0 USP. Per material 10 knots for every kind of knot were tested in a tensiometer, resulting in a total of 240...

Leeuwen, Nourah; Trimbos, J. Baptist

2012-01-01

141

Cranial tip suture in nasal tip contouring.  

Science.gov (United States)

The creation of both a functionally and aesthetically pleasing nasal tip contour is demanding and depends on various different parameters. Typically, procedures are performed with emphasis on narrowing the nasal tip structure. Excisional techniques alone inevitably lead to a reduction in skeletal support and are often prone to unpredictable deformities. But also long-term results of classical suture techniques have shown unfavorable outcomes. Particularly, pinching of the ala and a displacement of the caudal margin of the lateral crus below the cephalic margin belong to this category. A characteristic loss of structural continuity between the domes and the alar lobule and an undesirable shadowing occur. These effects lead to an unnatural appearance of the nasal tip and frequently to impaired nasal breathing. Stability and configuration of the alar cartilages alone do not allow for an adequate evaluation of the nasal tip contour. Rather a three-dimensional approach is required to describe all nasal tip structures. Especially, the rotational angle of the alar surface as well as the longitudinal axis of the lateral crus in relation to cranial septum should be considered in the three-dimensional analysis. Taking the various parameters into account, the authors present new aspects in nasal tip surgery which contribute to the creation of a functionally and aesthetically pleasing as well as durable nasal tip contour. PMID:25536137

Kovacevic, Milos; Wurm, Jochen

2014-12-01

142

Sutured tendon repair; a multi-scale finite element model.  

Science.gov (United States)

Following rupture, tendons are sutured to reapproximate the severed ends and permit healing. Several repair techniques are employed clinically, with recent focus towards high-strength sutures, permitting early active mobilisation thus improving resultant joint mobility. However, the arrangement of suture repairs locally alters the loading environment experienced by the tendon. The extent of the augmented stress distribution and its effect on the tissue is unknown. Stress distribution cannot be established using traditional tensile testing, in vivo, or ex vivo study of suture repairs. We have developed a 3D finite element model of a Kessler suture repair employing multiscale modelling to represent tendon microstructure and incorporate its highly orthotropic behaviour into the tissue description. This was informed by ex vivo tensile testing of porcine flexor digitorum profundus tendon. The transverse modulus of the tendon was 0.2551 ± 0.0818 MPa and 0.1035 ± 0.0454 MPa in proximal and distal tendon samples, respectively, and the interfibrillar tissue modulus ranged from 0.1021 to 0.0416 MPa. We observed an elliptically shaped region of high stress around the suture anchor, consistent with a known region of acellularity which develop 72 h post-operatively and remain for at least a year. We also observed a stress shielded region close to the severed tendon ends, which may impair collagen fibre realignment during the remodelling stage of repair due to the lack of tensile stress. PMID:24840732

Rawson, Shelley D; Margetts, Lee; Wong, Jason K F; Cartmell, Sarah H

2015-01-01

143

Iatrogenic Ulnar Nerve Injury post Laceration Suturing – An Unusual Presentation  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Nerve entrapment while suturing a lacerated wound is a complication that is easily avoidable. We report a case low ulnar nerve palsy due to nerve entrapment while suturing a lacerated wound. Case Report: A 48 year old lady came with complaints of pain and a lacerated wound over the dorsomedial aspect of lower third of the left forearm. The lacerated wound was sutured elsewhere one week back. She had fracture of lower third of the ulna which was stabilised with plates and screws using a separate dorsal incision. She developed ulnar claw hand on the third postoperative day. Strength duration curve revealed neurotmesis of ulnar nerve. Ulnar nerve exploration was done and the nerve was found to be ligated at the site of original laceration. The ligature was released and nerve was found to be thinned out at the site. There was no neurological recovery at 5 months follow up and reconstruction procedures in form of tendon tranfer are planned for the patient. Conclusion: This is a case of iatrogenic ulnar nerve palsy which is very rare in our literature. This can be easily avoided if proper care is taken while suturing the primary laceration. A nerve can be mistakenly sutured for a bleeding vein and proper exposure while suturing will be necessary especially at areas where nerves are superficial. Keywords: Iatrogenic, ulnar nerve palsy

Murali Mothilal

2013-07-01

144

Effect of {gamma}-irradiation on commercial polypropylene based mono and multi-layered retortable food packaging materials  

Energy Technology Data Exchange (ETDEWEB)

Irradiation processing of food in the prepackaged form may affect chemical and physical properties of the plastic packaging materials. The effect of {gamma}-irradiation doses (2.5-10.0 kGy) on polypropylene (PP)-based retortable food packaging materials, were investigated using Fourier transform infrared (FTIR) spectroscopic analysis, which revealed the changes happening to these materials after irradiation. The mechanical properties decreased with irradiation while oxygen transmission rate (OTR) was not affected significantly. Colour measurement indicated that Nylon 6 containing multilayer films became yellowish after irradiation. Thermal characterization revealed the changes in percentage crystallinity.

George, Johnsy [Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka 570011 (India)]. E-mail: g.johnsy@gmail.com; Kumar, R. [Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka 570011 (India); Sajeevkumar, V.A. [Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka 570011 (India); Sabapathy, S.N. [Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka 570011 (India); Vaijapurkar, S.G. [Defence Laboratory, Ratanada Palace, Jodhpur, Rajastan 342011 (India); Kumar, D. [Defence Laboratory, Ratanada Palace, Jodhpur, Rajastan 342011 (India); Kchawahha, A. [Defence Laboratory, Ratanada Palace, Jodhpur, Rajastan 342011 (India); Bawa, A.S. [Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka 570011 (India)

2007-07-15

145

Mass Spectrometry of Polymers: Polypropylene Glycol  

Science.gov (United States)

Mass spectra have been measured, using the field desorption technique, for polypropylene glycols with nominal mass-average relative molecular masses of 1000, 2000, 3000 and 4000. Ions of up to m/z 7400 have been observed. Major peaks in the spectra correspond to (M + H)+ ions. (M + Na)+ ions are observed if sodium iodide is added to the sample. There are strong peaks corresponding to fragmentation of the polymer chains close to their termini. It is suggested that these fragmentations are induced by the strong electric fields at the emitter.

Neumann, Gregory M.; Cullis, Peter G.; Derrick, Peter J.

1980-10-01

146

Improvement in the thermal performance of polypropylene  

International Nuclear Information System (INIS)

In the framework of the CRP our contribution consists of the two directions of investigation on the stabilization of polypropylene: one way follows the compatibilization of the blends of polypropylene with ethylene-propylene terpolymer in the presence of divinylbenzene, and the second way is represented by the nanocomposites polypropylene/calcium carbonate. The irradiation of ethylene-propylene diene terpolymer/polypropylene blends in the presence of divinylbenzene is an alternative procedure, which improves material lifetime and may be applied to material recycling. The selection of these systems is justified on the basis of their capacity on the providing free radicals. The two polymer components, EPDM and PP, can be degraded with various rates because of the different contents of methyl groups. The polymer samples consisted of both materials under various ratios (20:80, 40:60, 60:40 and 80:20); individual materials were also subjected to the action of (137Cs) ?-rays. Divinylbenzene, a hydrocarbon which plays the role of radical source was added iat the level of 5% (w/w). The stabilization effect was tested by two methods: oxygen uptake and IR spectroscopy at the characteristic bands (1720 cm-1 and 3350 cm-1) for carbonyl and hydroxyl groups, respectively. The ?-exposure induced a slower oxidative degradation in the presence of DVB. The carbonyl and hydroxyl indexes were calculated for all formulations. From oxidability investigatirmulations. From oxidability investigation the kinetic parameters for thermal oxidation of irradiated samples were calculated. Their modification depicts the radiochemical stability, which is an important feature in the long term applications. The ability of divinylbenzene in the radiation stabilization of studied polyolefin blends is discussed in relation with the modification of exposure dose and sample composition. The irradiation performed in air represents a proper test for the qualification of this polymeric system. Thermal and ? radiation stability of iPP containing CaCO3 nanoparticles were investigated by oxygen uptake procedure at 160oC. The loading of iPP matrix was maximum 25% (w/w). The behaviour on thermal oxidation was investigated for two formulations of iPP compounds differing by the surface characteristics of nanoparticles (i.e. uncoated and stearic acid-coated filler). Three irradiation doses (5, 15 and 25 kGy) were applied. The efficient protection of stabilizers that are present in the as-prepared formulations was emphasized by proper values of the kinetic parameters obtained for oxidation. The contribution of CaCO3 nanoparticles to the oxidative process of iPP is discussed. (author)

147

The nonlinear viscoelastic behavior of polypropylene  

CERN Document Server

A series of tensile relaxation tests is performed on isotactic polypropylene in the sub-yield and post-yield regions at room temperature. Constitutive equations are derived for the time-dependent response of a semicrystalline polymer at isothermal loading with small strains. Adjustable parameters in the stress-strain relations are found by fitting experimental data. It is demonstrated that the growth of the longitudinal strain results in an increase in the relaxation rate in a small interval of strains in the sub-yield domain. When the strain exceeds some critical value which is substantially less than the apparent yield strain, the relaxation process becomes strain-independent.

Drozdov, A D

2002-01-01

148

Modification of polypropylene fibres by preirradiation technique  

International Nuclear Information System (INIS)

Grafting of polypropylene fibres (POP) prepared by preirradiation techniques is discussed. A hydrophility change in irradiated and modified samples was studied. Irradiation was performed in a chamber type RCH-gamma-30 radiation equipment containing sup(60)Co. In the radiation modified samples of POP fibres prepared by preirradiation technique the humidity adsorption increased from 0.1% to 0.56% using a radiation dose of 24.5 kGy. The sorption properties of the samples were studied on McBeen balances with regard to temperature and water-vapour pressure. (author)

149

Modification of polypropylene fibres by preirradiation technique  

International Nuclear Information System (INIS)

The modification of polypropylene fibres (POP) ad POP fleece prepared by preirradiation technique is discussed. Grafting measure, hydrophility change and dyeing ability of the radiation modified samples were studied. For preirradiation a 60 CO source was used. For radiation-induced grafting 5-30 % acrylic acid solution was used. It was proved that the percentage of irradaiation-induced grafting of both POP fibres and POP fleece increased with an increase in the radiation dose and with the concentration of acrylic acid. Samples modified by this technique have a good dyeing ability. (author) 8 refs.; 3 tabs

150

A case report on a full-thickness chest wall reconstruction with polypropylene mesh and stainless steel mesh concurrently using a transverse rectus abdominis myocutaneous flap.  

Science.gov (United States)

A full-thickness chest wall resection requires subsequent chest wall reconstruction. A chest wall resection and reconstruction was performed using a transverse rectus abdominis myocutaneous (TRAM) flap, together with polypropylene mesh (Marlex mesh) and stainless steel mesh (SSM). A 71-year-old man was diagnosed as having recurrent lung cancer in the chest wall, and underwent surgical resection. Marlex mesh was sutured to the posterior wall of the surgical defect. A portion of the SSM was adjusted to the size of the defect and cut out. Its edges were folded to make the portion into a plate. This SSM plate was placed anteriorly to the Marlex mesh and sutured to the ribs. The Marlex mesh was folded back on the SSM plate by 2 cm and fixed. After the above procedures, a left-sided TRAM flap was raised through a subcutaneous tunnel up to the defect and sutured to the region. The patient was discharged from hospital 19 days postoperatively. The wound was fine and he had no flail chest or dyspnea, and carcinomatous pain resolved. PMID:17228288

Yoshino, Naoyuki; Yamauchi, Shigeo; Akimoto, Masataka; Hisayoshi, Takao; Koizumi, Kiyoshi; Shimizu, Kazuo

2006-12-01

151

Disposable circumcision suture device: clinical effect and patient satisfaction  

Directory of Open Access Journals (Sweden)

Full Text Available In our experience patients undergoing circumcision are mostly concerned about pain and penile appearances. We conducted a prospective randomized trial to assess the benefits of a new disposable circumcision suture device (DCSD. A total of 942 patients were equally divided into three groups (conventional circumcision, Shang ring and disposable suture device group. Patients in the DCSD group were anesthetized with compound 5% lidocaine cream, the others with a 2% lidocaine penile block. Operation time, intra-operative blood loss, incision healing time, intra-operative and post-operative pain, the penile appearance and overall satisfaction degree were measured. Operation time and intra-operative blood loss were significantly lower in the Shang ring and suture device groups compared to the conventional group (P < 0.001. Intra-operative pain was less in the suture device group compared with the other two groups (P < 0.001; whereas post-operative pain was higher in the conventional group compared to the other two groups (P < 0.001. Patients in the suture device (80.57% and Shang ring (73.57% groups were more satisfied with penile appearances compared with the conventional circumcision group (20.06%, P < 0.05. Patients in suture device group also healed markedly faster than the conventional group (P < 0.01. The overall satisfaction rate was better in the suture device group (78.66% compared with the conventional (47.13% and Shang ring (50.00% groups (P < 0.05. The combination of DCSD and lidocaine cream resulted in shorter operation and incision healing times, reduced intra-operative and post-operative pain and improved patient satisfaction with the cosmetic appearances.

Bo-Dong Lv

2014-06-01

152

Study of Insertion Force and Deformation for Suturing With Precurved NiTi Guidewire.  

Science.gov (United States)

This research presents an experimental study evaluating stomach suturing using a precurved nickel-titanium (NiTi) guidewire for an endoscopic minimally invasive obesity treatment. Precise path planning is critical for accurate and effective suturing. A position measurement system utilizing a hand-held magnetic sensor was used to measure the shape of a precurved guidewire and to determine the radius of curvature before and after suturing. Ex vivo stomach suturing experiments using four different guidewire tip designs varying the radius of curvature and bevel angles were conducted. The changes in radius of curvature and suturing force during suturing were measured. A model was developed to predict the guidewire radius of curvature based on the measured suturing force. Results show that a small bevel angle and a large radius of curvature reduce the suturing force and the combination of small bevel angle and small radius of curvature can maintain the shape of guidewire for accurate suturing. PMID:25480363

Wang, Yancheng; Chen, Roland K; Tai, Bruce L; Xu, Kai; Shih, Albert J

2015-04-01

153

Study on thermal decomposition of calix[4]arene and its application in thermal stability of polypropylene  

Energy Technology Data Exchange (ETDEWEB)

Thermal decomposition kinetics of calix[4]arene (C4) was investigated using thermogravimetric analysis (TGA) and derivative of TG curve (DTG). TG experiments were carried out under static air atmosphere with nominal heating rates of 1.0, 2.5, 5.0 and 10.0 K/min. Model-fitting methods and model-free methods such as Friedman and Ozawa-Flynn-Wall methods were employed to evaluate the kinetic parameters such as activation energy (E{sub a}), exponential factor (ln A) and reaction order (n). To determine the antioxidant property of C4 the non-isothermal kinetics of polypropylene (PP) with C4 as additive was studied. The FTIR, ESR and {sup 13}C NMR CP-MAS techniques were used to propose the decomposition mechanism of C4 in the presence of PP.

Chennakesavulu, K., E-mail: chennanml@yahoo.com [National Metallurgical Laboratory Madras Centre, CSIR Complex, Taramani, Chennai 600113 (India); Basariya, M. Raviathul; Sreedevi, P.; Bhaskar Raju, G.; Prabhakar, S.; Rao, S. Subba [National Metallurgical Laboratory Madras Centre, CSIR Complex, Taramani, Chennai 600113 (India)

2011-03-10

154

Nanoparticle effects during pressure-induced crystallization of polypropylene  

International Nuclear Information System (INIS)

We describe here phase and morphological changes that are induced when polypropylene containing dispersion of nanoclay is isothermally crystallized in the pressure range of 0.1-200 MPa. To delineate and separate the effects of applied crystallization pressure from nanoparticle effects, a relative comparison is made between neat polypropylene and polypropylene containing dispersion of nanoclay under similar experimental conditions. The significant finding is that nanoparticles of clay interact with the host polypropylene in a manner such that they alter the structural morphology of ?- and ?-crystals of polypropylene presumably via nanoparticle interface driven evolution. Interestingly, nanoclay promotes the formation of ?-phase at low pressure, which is expected to have significant bearing on physico-chemical and mechanical properties. The equilibrium melting point measurements point to thermodynamic interaction between nanoclay and polypropylene, which is supported by the change in glass transition temperature and modification of absorption bands of polypropylene between 995 and 973 cm-1 corresponding to tertiary methyl skeletal in Fourier transform infrared spectrum

155

Degradation study of polypropylene (PP and bioriented polypropylene (BOPP in the environment  

Directory of Open Access Journals (Sweden)

Full Text Available Polymers are vastly employed for numerous purposes in different industrial segments and generate soaring quantities of discarding in the environment. This research analyzed the degradability/biodegradability of polypropylene films (PP and Bioriented polypropylene (BOPP polymers after 11 months interred in the São Giácomo landfill in Caxias do Sul. Comparing the buried PP film to a sample of virgin PP, two peaks of degrading activity appeared at the TG curve as well as structure modification typified by occurrence of new absorption bands at FTIR, which can be credited to changes in crystallinity. Thermal analysis carried out on the buried PP and BOPP showed decreases in the percentage of crystallinity due to chain scission. The major reduction was observed in the PP, since its crystallinity is a consequence of polymerization instead of chain orientation processes, as in BOPP. Cracks and erosion of the polymer surface were detected in both PP and BOPP, indicating degrading processes by microorganisms.

Carina Longo

2011-12-01

156

Degradation study of polypropylene (PP) and bioriented polypropylene (BOPP) in the environment  

Scientific Electronic Library Online (English)

Full Text Available Polymers are vastly employed for numerous purposes in different industrial segments and generate soaring quantities of discarding in the environment. This research analyzed the degradability/biodegradability of polypropylene films (PP) and Bioriented polypropylene (BOPP) polymers after 11 months int [...] erred in the São Giácomo landfill in Caxias do Sul. Comparing the buried PP film to a sample of virgin PP, two peaks of degrading activity appeared at the TG curve as well as structure modification typified by occurrence of new absorption bands at FTIR, which can be credited to changes in crystallinity. Thermal analysis carried out on the buried PP and BOPP showed decreases in the percentage of crystallinity due to chain scission. The major reduction was observed in the PP, since its crystallinity is a consequence of polymerization instead of chain orientation processes, as in BOPP. Cracks and erosion of the polymer surface were detected in both PP and BOPP, indicating degrading processes by microorganisms.

Carina, Longo; Michele, Savaris; Mára, Zeni; Rosmary Nichele, Brandalise; Ana Maria Coulon, Grisa.

2011-12-01

157

Failure strength of repair devices versus meniscus suturing techniques.  

Science.gov (United States)

The purpose of this study was to compare the load to failure of different common suturing techniques with repair devices. Seventy-one calf medial menisci were cut to simulate peripheral longitudinal tears and repaired with one of 13 repair techniques. The two parts of the meniscus were pulled using the Instron tensometer until failure occurred. The techniques and repair devices tested were vertical (0 PDS, 2-0 PDS, 2-0 Ethibond), horizontal (0 PDS, 2-0 PDS, 2-0 Ethibond) suturing, T-fix, Mitek, Clearfix screw, Clearfix dart, Biostinger, S-D-sorb, and Artrex dart. The strongest repair method in our study was the vertical sutures with 0 PDS. In this study the mean failure strength of all meniscal repair devices was lower than that of the vertical and horizontal suturing techniques. All meniscus repair devices except T-fix and in some the Arthrex dart (40% broken up) pulled out of the menisci. Devices which had only horizontally placed barbs had lower mean failure strength. Failure strength of T-fix was similar to horizontal sutures with 2-0 Ethibond and 2-0 PDS. In conclusion, because all meniscal repair devices had inferior results, when such devices are used, postoperative rehabilitation should not be hastened, and their inferior primary stability should be kept in mind. PMID:11819017

A?ík, Mehmet; Sener, Nadir

2002-01-01

158

Recognizing surgeon's actions during suture operations from video sequences  

Science.gov (United States)

Because of the shortage of nurses in the world, the realization of a robotic nurse that can support surgeries autonomously is very important. More specifically, the robotic nurse should be able to autonomously recognize different situations of surgeries so that the robotic nurse can pass necessary surgical tools to the medical doctors in a timely manner. This paper proposes and explores methods that can classify suture and tying actions during suture operations from the video sequence that observes the surgery scene that includes the surgeon's hands. First, the proposed method uses skin pixel detection and foreground extraction to detect the hand area. Then, interest points are randomly chosen from the hand area so that their 3D SIFT descriptors are computed. A word vocabulary is built by applying hierarchical K-means to these descriptors, and the words' frequency histogram, which corresponds to the feature space, is computed. Finally, to classify the actions, either SVM (Support Vector Machine), Nearest Neighbor rule (NN) for the feature space or a method that combines "sliding window" with NN is performed. We collect 53 suture videos and 53 tying videos to build the training set and to test the proposed method experimentally. It turns out that the NN gives higher than 90% accuracies, which are better recognition than SVM. Negative actions, which are different from either suture or tying action, are recognized with quite good accuracies, while "Sliding window" did not show significant improvements for suture and tying and cannot recognize negative actions.

Li, Ye; Ohya, Jun; Chiba, Toshio; Xu, Rong; Yamashita, Hiromasa

2014-03-01

159

Polypropylene and polycarbonate radiosterilization: effects on the stress resistance  

International Nuclear Information System (INIS)

The gamma radiation effect on polymer sterilization used in the fabrication of medical supplies, national polycarbonate and polypropylene, was studied in function of the tensile strength. During the polycarbonate irradiation occur the scission of polymer chain and the crosslinking/scission of the polypropylene, but in the sterilization dose, 25 kGy, does not occur expressive changes in the tensile strength. After the polypropylene sterilization the tensile strength continues increasing as consequence of the crosslinking. Since the sixth day the oxidation reaction predominates as consequence of the radical migration to the amorphous region. (author). 7 refs, 6 figs

160

Radiation stability of polypropylene/lead zirconate composites  

Science.gov (United States)

The effects of PbZrO3 filler in polypropylene were studied by isothermal and nonisothermal chemiluminescence and FT-IR spectroscopy after ?(137Cs)-irradiation at 20, 50, 100 and 250 kGy relative to neat material. For the two filler concentrations (2 and 5 wt%) the improvement in radiation stability can be noticed. The increase in the filler concentration stabilizes polypropylene matrix, whose oxidation rate decreases sharply even at 250 kGy. The interaction of polypropylene matrix with filler is discussed based on the adsorption of free radicals on zirconate particles and the electronic coupling of radiolysis intermediates and filler cations.

Burnea, L. C.; Zaharescu, T.; Dumitru, A.; Plesa, I.; Ciuprina, F.

2014-01-01

161

Electrophysical Properties of Composites Based on Atactic Polypropylene  

Science.gov (United States)

Results of investigations of the dielectric permittivity and dielectric loss tangent are presented for a wide frequency range. Physical and chemical properties of modified atactic polypropylene are investigated and experimental parameters of its adhesion to the steel and concrete surfaces are given. It is demonstrated that atactic polypropylene can be used as an electric insulator and water repellent to protect from corrosion metal structures and concrete products used in power engineering. Modification of atactic polypropylene increases the real component of the dielectric permittivity and decreases the dielectric loss tangent, thereby significantly decreasing its conductive properties. This can be used for electric insulation of energy-intensive units.

Debelova, N. N.; Suslyaev, V. I.; Gorlenko, N. P.; Zhuravlev, V. A.; Zav'yalova, E. N.; Dotsenko, O. A.; Zav'yalov, P. B.; Ul'yanova, O. A.

2014-07-01

162

2-hydroxyethyl methacrylate composite - polypropylene mesh for preventing peritoneal adhesions in female dogs / Compósito 2-hidroxietil dimetacrilato-tela de polipropileno para prevenção de aderências peritoneais em cadelas  

Scientific Electronic Library Online (English)

Full Text Available OBJETIVO: Avaliar se o revestimento da face visceral de uma tela de polipropileno com 2-hidroxietil dimetacrilato (p(HEMA)) poderia evitar aderências peritoniais em cadelas. MÉTODOS: Em oito animais (Grupo PP) foram implantadas telas de polipropileno para correção de um defeito do músculo reto abdom [...] inal, enquanto em outro grupo (Grupo PH) fez-se a implantação de uma tela de polipropileno cuja face peritonial foi revestida por 2-hidroxietil dimetacrilato (p(HEMA)). RESULTADOS: Foram observados 62,5% de aderências peritoniais sobre a tela nos animais do Grupo PP, enquanto que no Grupo PH estas não ocorreram, exceto sobre a linha se sutura. CONCLUSÃO: O hidrogel de p(HEMA) foi bem tolerado pelos animais e mostrou-se efetivo na prevenção das aderências viscerais e omentais sobre a tela de polipropileno. Abstract in english PURPOSE: To evaluate whether the lining facing the visceral side of polypropylene mesh made with 2-hydroxyethyl methacrylate (p(HEMA)) hydrogel could avoid peritoneal adhesion in female dogs. METHODS: Eight animals (group PP) had a polypropylene mesh implanted to correct a defect in the rectal abdom [...] inal muscle, whereas in the other group (group PH) the polypropylene mesh was coated with p(HEMA) composite on the surface facing the peritoneal area. RESULTS: Adhesions were observed on the mesh in 62.5% of the PP group. In the PH group adhesions were present only on the suture lines. CONCLUSION: p(HEMA) hydrogel was well tolerated and effective in avoiding visceral and omental adhesions on the surface of the polypropylene mesh.

Marcelo Seixo de Brito e, Silva; Renato Miranda de, Melo; Liliana Borges de, Menezes; Sonia Maria, Malmonge; Leandro Guimarães, Franco; Neusa Margarida, Paulo.

2010-08-01

163

2-hydroxyethyl methacrylate composite - polypropylene mesh for preventing peritoneal adhesions in female dogs Compósito 2-hidroxietil dimetacrilato-tela de polipropileno para prevenção de aderências peritoneais em cadelas  

Directory of Open Access Journals (Sweden)

Full Text Available PURPOSE: To evaluate whether the lining facing the visceral side of polypropylene mesh made with 2-hydroxyethyl methacrylate (p(HEMA hydrogel could avoid peritoneal adhesion in female dogs. METHODS: Eight animals (group PP had a polypropylene mesh implanted to correct a defect in the rectal abdominal muscle, whereas in the other group (group PH the polypropylene mesh was coated with p(HEMA composite on the surface facing the peritoneal area. RESULTS: Adhesions were observed on the mesh in 62.5% of the PP group. In the PH group adhesions were present only on the suture lines. CONCLUSION: p(HEMA hydrogel was well tolerated and effective in avoiding visceral and omental adhesions on the surface of the polypropylene mesh.OBJETIVO: Avaliar se o revestimento da face visceral de uma tela de polipropileno com 2-hidroxietil dimetacrilato (p(HEMA poderia evitar aderências peritoniais em cadelas. MÉTODOS: Em oito animais (Grupo PP foram implantadas telas de polipropileno para correção de um defeito do músculo reto abdominal, enquanto em outro grupo (Grupo PH fez-se a implantação de uma tela de polipropileno cuja face peritonial foi revestida por 2-hidroxietil dimetacrilato (p(HEMA. RESULTADOS: Foram observados 62,5% de aderências peritoniais sobre a tela nos animais do Grupo PP, enquanto que no Grupo PH estas não ocorreram, exceto sobre a linha se sutura. CONCLUSÃO: O hidrogel de p(HEMA foi bem tolerado pelos animais e mostrou-se efetivo na prevenção das aderências viscerais e omentais sobre a tela de polipropileno.

Marcelo Seixo de Brito e Silva

2010-08-01

164

Superficial wound closure complications with barbed sutures following knee arthroplasty.  

Science.gov (United States)

As quality measures may be increasingly used in knee surgery reimbursement, an important focus in outcome assessment will shift toward minimizing complications and increasing efficiency in knee arthroplasty reconstruction. The purpose of this study was to evaluate the efficacy of barbed, absorbable sutures in closure of the longitudinal surgical incision following knee arthroplasty, using post-operative complication occurrences. In 416 operations, primary outcomes assessed were deep infection, superficial infection, dehiscence, or stitch abscesses. Secondary outcomes included self-limiting eschar, severe effusion, arthrofibrosis, and keloid formation. Evaluation of overall primary outcomes showed a higher rate of wound complications using barbed sutures (P < 0.001). With increased rates of infection and overall closure related complications, this study shows that barbed suture use for superficial closure after knee arthroplasty should be avoided. PMID:24184326

Campbell, Abigail L; Patrick, David A; Liabaud, Barthelemy; Geller, Jeffrey A

2014-05-01

165

Modified cross-pin femoral fixation using long needles, polydioxanone suture, and traction suture for hamstring anterior cruciate ligament reconstruction.  

Science.gov (United States)

The use of cross-pin femoral fixation in anterior cruciate ligament (ACL) reconstruction using semitendinosus and gracilis (ST/G) tendons has been shown to be biomechanically sound. As a result of some technical problems that we encountered, we modified the technique of the DePuy OrthoTech Xact ACL Graft Fixation System (DePuy, Warsaw, IN) using No. 2/0 polydioxanone suture (PDS) with long needles normally used for inside-out meniscal repair. In addition, a No. 5 Ethibond suture loop (Ethicon, Somerville, NJ) is used for traction of the ST/G graft up the femoral tunnel. Using a 2-suture loops technique, the traction suture loop offers a more effective in-line pull for the graft and it pulls the ST/G loops slightly higher than the alignment PDS. By so doing, it lessens the chance of kinking the alignment guidewire or even amputating the graft. Although not reported in literature, this type of graft complication is possible in other single-alignment suture or guidewire techniques. PMID:11239357

Lam, James J.; Poon, Alex K. c.; Ko, Peter P. S.; Ko, Yuen; Tsang Wl, Wai-luk

2001-03-01

166

Anisotropic thermal conductivity in sheared polypropylene  

Energy Technology Data Exchange (ETDEWEB)

We discuss the anisotropy of the thermal conductivity tensor in polymer flow in this paper. Isotactic polypropylene (iPP) specimens were deformed by injection moulding at high shear rates and by steady shear at low shear rates, and were then quenched. The thermal conductivities parallel and perpendicular to the shear direction were measured using modulated differential scanning calorimetry (MDSC) in accordance with the ASTM E1952-01. The measured results showed that the thermal conductivity of the sheared polymer was anisotropic with an increase in the shear direction. The thermal conductivity can be regarded as varying either with the strain or the stress, as suggested by Van den Brule (1989). In addition to the Van den Brule mechanism, crystallization during flow also changes the thermal conductivity and this effect may often be dominant. Suggestions for procedures in processing computations, based on both effects, are given. (orig.)

Dai, Shao Cong; Tanner, Roger I. [The University of Sydney, Rheology Research Group, School of Aerospace, Mechanical and Mechatronic Engineering, Sydney, NSW (Australia)

2006-01-01

167

Development of radiation cross-linked polypropylene  

International Nuclear Information System (INIS)

Polyethylene (PE) is easily cross-linked by irradiation, and radiation crosslinked PE is widely applied to heat-resisting wires and heat-shrinkable tubes. Although polypropylene (PP), which has higher mechanical strength and a higher melting point than PE, has superior heat resistance, it is not easily cross-linked by irradiation. Therefore, radiation cross-linked PP is not in practical application in most cases. The authors pursued research on radiation cross-linked PP by selecting suitable PP type, controlling the crystallinity and adding multi-functional monomers. As the result, by adding multi-functional monomer TMPTMA (trimethyrolpropanetrimethacrylate) to random-type PP and quenching it to lower its crystallinity, PP that has superior heat resistance and capable of radiation cross-link was successfully developed. (author)

168

POLYPROPYLENE/CLAY NANOCOMPOSITES: SYNTHESIS AND CHARACTERIZATION  

Directory of Open Access Journals (Sweden)

Full Text Available Polypropylene nanocomposites were synthesized by using the method of mixing in the molten state. Nanocomposites were obtained in twin-screw co-rotating extruders and the nanocomposites were prepared with percentage of nanoclay (C2 from 5 wt-%, with and without compatibilizer agent (PP-g-MA. The thermal (DSC, TGA, morphology (XRD, TEM, and dynamical mechanical (DMA properties of the nanocomposites were characterized. All nanocomposites prepared are in intercalated state as corroborated by XRD and TEM. The Tm and Xc were not affected by the presence of clay, PP-g-MA, or processing support. The incorporation of clay and compatibilizer agent increases the thermal stability and heat deflection temperature (HDT.

MÓNICA A PÉREZ

2010-12-01

169

Interrupted or continuous-intradermal suturing? Statistical analysis of postoperative scars  

Directory of Open Access Journals (Sweden)

Full Text Available Background and Design: Postoperative scar development is an important problem for patients treated in plastic surgery clinics. Most patients think that continuous intradermal suturing is superior to interrupted suturing because they assume that it creates less scarring. We evaluated scars that form following intradermal and interrupted suturing. This article presents our controlled study that objectively compared the scars on patients' faces using a wound evaluation scale. Materials and Methods: Thirty-five patients, who had undergone operations on the bilateral cheeks, were included in this study. Thirty patients were female; five patients were male. Their mean age was 40.05 years. The average scar evaluation time after surgery was 9.05 months. Elliptical excisions were made on the lesions under local anesthesia. The incisions on the right cheeks were sutured with 6/0 monofilament nonabsorbable sutures using the continuous intradermal suturing technique. The left cheek incisions were sutured with same sutures using the interrupted suturing method. Results: The patients were evaluated 7–11 months after operation (mean: 9.05 months using the Stony Brook Scar Evaluation Scale. A Related Samples T-test was used for statistical evaluation of the differences between the suturing techniques. No significant differences were noted in scar formation between the two suturing methods (p>0.05. Conclusion: We found no differences in scar formation between the two frequently used suturing techniques studied here. We believe that the suturing technique is a less important determinant of scar formation than are other factors.

Elif Sar?

2014-12-01

170

Mechanical Properties of Recycled Compounds of Polypropylene for Building Products  

Directory of Open Access Journals (Sweden)

Full Text Available The recycling of polymeric materials has been highly discussed due to economic and environmental factors. It is well known that, polypropylene can be used for many applications and, depending on the final characteristics that are necessary, they use different additives. So, this study aims to evaluate the mechanical properties of compositions containing recyclable polypropylene from different sources and with different composition and define the best composition using the maximum percentage of polypropylene with lower mechanical properties, which is a material considered difficult to incorporate in the process due to the high percentage of gas and impurities and the one with lowest cost. For the evaluation of mechanical properties, tensile and flexion tests were performed and, also, optical microscopy, which proved to be possible to use this kind of polypropylene in high percentages, since the conditions of mixture are guaranteed.

Glaucea Warmeling Duarte

2013-10-01

171

Radiation cross-linking of montmorillonite/polypropylene composite  

International Nuclear Information System (INIS)

Polypropylene/montmorillonite composite was prepared via melt compounding process. The dispersion of montmorillonite in the composite was analyzed by XRD (X-ray diffraction) and TEM (Transmission electron microscope). Electronic radiation was applied to make the composite radiation cross-linked in air. The effect of cross-linking agent and montmorillonite on the properties of polypropylene cross-linking was studied. The results indicated that cross-linking did not take place in absence of cross-linking agent, while in presence of both cross-linking agent and montmorillonite polypropylene cross-linking occurred in certain absorbed dose range. The cross-linked polypropylene/montmorillonite composite exhibited improved mechanical properties. (authors)

172

Thermal conductivity of polypropylene filled with inorganic particles  

International Nuclear Information System (INIS)

Highlights: ? Better thermal conductivity in PP samples filled with h-BN. ? Filler particle size affect composite thermal conductivity. ? Thermal conductivity was measured for different filler amount. -- Abstract: Boron and aluminium nitride, as well as carbon materials, were used as fillers for polypropylene to increase its thermal conductivity. Better thermal conductivity was observed for samples filled with nanosized BN. All composites show thermal stability up to 250 °C. Filling of polypropylene was shown to affect crystallinity degree, adding of BN and carbon nanotubes results in the increase in crystallinity of polypropylene. It was observed that BN forms chemical bonds with polymer matrix, whereas no evidence of such bonds was found in case of polypropylene filled with AlN particles

173

Graft copolimerization of hydrophilic monomers onto irradiated polypropylene fibers  

International Nuclear Information System (INIS)

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

174

Thermal conductivity of polypropylene filled with inorganic particles  

Energy Technology Data Exchange (ETDEWEB)

Highlights: ? Better thermal conductivity in PP samples filled with h-BN. ? Filler particle size affect composite thermal conductivity. ? Thermal conductivity was measured for different filler amount. -- Abstract: Boron and aluminium nitride, as well as carbon materials, were used as fillers for polypropylene to increase its thermal conductivity. Better thermal conductivity was observed for samples filled with nanosized BN. All composites show thermal stability up to 250 °C. Filling of polypropylene was shown to affect crystallinity degree, adding of BN and carbon nanotubes results in the increase in crystallinity of polypropylene. It was observed that BN forms chemical bonds with polymer matrix, whereas no evidence of such bonds was found in case of polypropylene filled with AlN particles.

Muratov, D.S., E-mail: muratov@misis.ru; Kuznetsov, D.V.; Il’inykh, I.A.; Mazov, I.N.; Stepashkin, A.A.; Tcherdyntsev, V.V.

2014-02-15

175

Tension suture fixation using 2 washers for proximal humeral fractures.  

Science.gov (United States)

The surgical treatment for proximal humeral fractures is challenging, especially in patients with osteoporosis. Locking plates and intramedullary nails have been widely used with satisfactory results, but previously reported complications have not been substantially reduced. Several authors have emphasized the importance of maintaining soft tissues around the proximal humerus with respect to limiting displacement and maintaining stability. To prevent postoperative complications, such as fixation failure and malunion, several supplementary suture techniques using nonabsorabable sutures that allow for the incorporation of the rotator cuff as a fixation point have been described. PMID:22385595

Cho, Chul-Hyun; Jung, Gu-Hee; Song, Kwang-Soon

2012-03-01

176

Radiation resistant modified polypropylene; Polipropylen modyfikowany odporny radiacyjnie  

Energy Technology Data Exchange (ETDEWEB)

Radiation technology for production of radiation resistant polypropylene for medical use has been presented. The method consists in radiation induced copolymerization of polypropylene with ethylene and addition of small amount of copolymer of polyethylene and vinyl acetate. The material of proposed composition has a very good mechanical properties and elevated radiation resistivity decided on possibility of radiosterilization of products made of this material and designed for medical use. 3 figs, 3 tabs.

Bojarski, J.; Zimek, Z. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

1997-10-01

177

Rheometric research of polypropylene Licocene PP2602 melts  

OpenAIRE

Purpose: To comprehend and ascertain reasons of the transition into the non-Newtonian viscosity zone for the melted polypropylene material, depending upon the number of recycling series.Design/methodology/approach: There were carried researches on rheological features of the primary material of the melted polypropylene Licocene PP2602, subjected to be processed repeatedly in as many series as needed, using the Brookfield viscometer CAP2000+ within the temperature range 130-200ºC and the shea...

Romanuke, V. V.; Mandzyuk, I. A.

2011-01-01

178

Study on the Dynamic Performance of Polypropylene Fiber Reinforced Concrete  

OpenAIRE

The dynamic performance of polypropylene fiber reinforced concrete is studied with the SHPB experiment. The relationship of the strain-stress curves are all obtained in the experiment. The crack characteristics of polypropylene reinforced concrete and plain concrete are also investigated. Analyzed the relation between the character on the crack surface of concrete and material properties and the impact pressure. Also the multi-fractal characteristics are given on the crack surface of concrete...

Zhang Ying; Zheng Chunhang; Wu Rujun; Chen Xi; Guoping Jiang

2013-01-01

179

Strategies for improving mechanical properties of polypropylene/cellulose composites  

OpenAIRE

The interest for polypropylene/cellulose composites has experienced a great increase in different applications such as car interiors and construction materials. Cellulose fibres are inexpensive, renewable, biodegradable, they present lower density and their mechanical properties can be compared to those of inorganic fillers. However, several factors must be considered when designing polypropylene/cellulose composites: the poor compatibility between the hydrophilic fibres and the hydrophobic t...

Espert, Ana

2005-01-01

180

Physicomechanical properties of polypropylene composites filled by modified nano silicates  

International Nuclear Information System (INIS)

This article is devoted to physicomechanical properties of polypropylene composites filled by modified nano silicates. Thus, the electron microscopy, mechanical, dynamical, and rheological study of polypropylene, filled by nano silica gel and silica gel modified by gamma-aminopropyltrimethoxysilane (C6H17O3N) was conducted. It was found that modification of silica gel surface by hydrophobic agent improve the interaction of filler particles with polymer matrix, improve the uniform distribution, prevent the agglomerate formation, increase the elasticity of composite material.

181

Application of gas chromatography to the investigations on polypropylene radiolysis  

International Nuclear Information System (INIS)

Refinement of the gas chromatography (GC) instrumental approach permitted not only improvement of investigation in basic research, but also development of a new kind of polypropylene blends, more suitable for the production of medical devices and radiation sterilization. It has been shown, that using the GC method not only methane and carbon dioxide can be measured, but also the consumption of oxygen which reacts with free radicals on the polypropylene chain

182

A Study of the Efficacy of Antibacterial Sutures for Surgical Site Infection: A Retrospective Controlled Trial  

OpenAIRE

To reduce bacterial adherence to surgical sutures, triclosan-coated polyglactin 910 suture materials with antiseptic activity were developed. The aim of this study was to evaluate whether the incidence of surgical site infections can be reduced when triclosan-coated sutures are used. Until December 2009, we used conventional polyglactin 910 sutures (VICRYL, Ethicon) for the closure of the fascia in digestive tract surgery. Therefore, for the control group we retrospectively collected surveill...

Hoshino, Seiichiro; Yoshida, Yoichiro; Tanimura, Syu; Yamauchi, Yasushi; Noritomi, Tomoaki; Yamashita, Yuichi

2013-01-01

183

Evaluation of five different suture materials in the skin of the earthworm (Lumbricus terrestris)  

OpenAIRE

The purpose of this study was to determine which suture material is the most appropriate for dermal closure of terrestrial annelids. This paper describes the tissue reactions of the earthworm, Lumbricus terrestris, to five different types of suture materials in order to determine which suture material is the most appropriate for dermal closure. Silk, monofilament nylon, polydiaxonone, polyglactin 910, and chromic gut were studied. There was mild to moderate tissue reaction to all five suture ...

Salgado, Melissa A.; Lewbart, Gregory A.; Christian, Larry S.; Griffith, Emily H.; Law, Jerry Mchugh

2014-01-01

184

Complexity of suture zones:Example from the Yarlung Zangbo Suture Zone , southern Tibet. (Invited)  

Science.gov (United States)

Decade-long investigation of the Yarlung Zangbo Suture Zone (YZSZ), southern Tibet, has revealed it's high complexity in terms of structure, geochronology and metamorphic and igneous histories. For instance, YZSZ comprises Late Devonian to mid-Miocene rocks, metamorphic intensities vary from high-grade to very-low grade and deformation styles range from ductile to brittle. Late Devonian rocks (363.7 × 1.7 Ma) are alkalic gabbros resulting from activity of a plume active within the Paleo-Tethys basin. Two ophiolite sub-groups are recognized. Sub-group 1 is Mid- to Late Jurassic (150-177 Ma) in age and ill-defined because only few sequences have been found and studied so far. IThis sub-group is probably derived from the destruction of a marginal basin comprising intra-oceanic arc and fore-arc settings. Spontang and Zedong sequences are good examples of this sub-group. Sub-group 2 is Lower Cretaceous (120-130 Ma) and represents the destruction of a marginal basin comprising an arc-back-arc system. These ophiolites are spatially associated with ophiolitic mélanges and flysch respectively representing the reworking of the Cretaceous ophiolites and Indian continental margin and the Neo-Tethyan ocean floor although such affinities need clarification. Most ophiolitic sequences belong to sub-group 2 such as Xiugubagu, Saga, Xigaze. Amphibolite and garnet amphibolite blocks (123-130 Ma) found within the ophiolitic mélange share similar geochemical attributes with sub-group 2 ophiolites. Their protoliths were probably generated within back-arc spreading center and metamorphosed in a subduction zone at depth around 50 km. Some radiometric ages suggest events at 80 Ma and 90 old represent the entry of Indian continental margin into the intra-oceanic subduction zone and/or obduction of ophiolites. However these ages seem to be very rare throughout the whole suture zone and are therefore considered as resulting from local metamorphic events. Some alkaline igneous rocks (131-144 Ma) within the flysch could represent Kerguelen OIB plume products. The study of igneous blocks and the sedimentary matrix suggests a continuous passive margin model. The Miocene (11-17 Ma) post-collisional ultrapotassic rocks discovered in 2006-2007 result from the collapse of the Tibet Plateau accommodated by E-W extensional regime. They carry crustal xenoliths of metamorphic origins representing a window through the deep crustal section underlying the YZSZ. The geochemistry of these shoshonitic intrusives shows strong subduction components resulting from the metasomatism of the mantle wedge over the subduction zones accommodating the closure of Neo-Tethys basin. ?Nd values suggest the source reservoir for these magmatic rocks has mostly Asian late Precambrian affinity. YZSZ contains features related to the interplay between India and Eurasian plates once separated by the large Tethys Ocean or one of associated smaller basin such as the Neo-Tethys basin. However, the complexity of the YZSZ and the diversity of rock types call for a redefinition of the suture zone to include such a mosaic of terranes now tectonically adjacent within this narrow orogenic collisional zone.

Hebert, R.; Guilmette, C.

2013-12-01

185

Development of novel melt-compounded starch-grafted polypropylene/polypropylene-grafted maleic anhydride/organoclay ternary hybrids  

OpenAIRE

Starch-grafted polypropylene (PP-g-starch)/organoclay nanocomposites were melt-compounded using a corotating twin-screw extruder. Homopolymer or copolymer-based polypropylene-grafted maleic anhydrides (PP-g-MA) with different molecular weights and different maleic anhydride (MA) grafting levels were added at different weight contents as compatibilizer. Two organo-modified montmorillonites were used, the first one containing polar functional groups (Cloisite®30B) having affinity to the st...

Lafranche, E.; Tessier, R.; Krawczak, P.

2012-01-01

186

Effect of Maleated Polypropylene (MAPP) on the Tensile, Impact and Thickness Swelling Properties of Kenaf Core – Polypropylene Composites  

OpenAIRE

The study on the kenaf core fiber – polypropylene (PP) composites with treated and non-treated maleated polypropylene (MAPP) was done. Epolene-43 which is commercially MAPP was used to determine MAPP’s effectiveness as a coupling agent for kenaf fiber-composites. The hot pressing system for producing kenaf core-PP composite has been used. The tensile, impact and thickness swelling results of the epolene 43 treated composite samples were better than those of the untreated composite...

Mohamad Jani Saad

2011-01-01

187

Durability of three layer polypropylene coated steel pipe at elevated temperatures; Sanso polypropylene hifuku kokan no koon taikyusei  

Energy Technology Data Exchange (ETDEWEB)

This paper describes corrosion resistance of polypropylene coating newly developed for pipelines operating at elevated temperatures. For the experiment, polypropylene triple layer coated steel pipe with special antioxidant was used. Indentation test at temperatures between 40 and 100 {degree}C, impact test at temperatures between 40 and 80 {degree}C, and peeling test for measuring adhesive strength of the coating at temperatures between 20 and 100 {degree}C were conducted to examine the mechanical property of the polypropylene coating. In addition, antioxidation durability of polypropylene coating with a standard amount of antioxidant was examined by the deterioration time measurement at temperatures between 120 and 160 {degree}C, to estimate its lifetime. Consequently, the polypropylene coating provided superior indentation resistance, impact strength and peeling strength to the polyethylene coating. The polypropylene coating with special antioxidant also provided excellent antioxidation property. It was found that this coating prevents the residual internal stress cracking formed from defects at the elevated temperature. 9 refs., 8 figs., 4 tabs.

Funatsu, S.; Kariyazono, Y.; Miyajima, Y.; Ishida, M.; Endo, E. [Nippon Steel Corp., Tokyo (Japan)

1997-02-07

188

Penile torsion correction by diagonal corporal plication sutures  

Scientific Electronic Library Online (English)

Full Text Available Penile torsion is commonly encountered. It can be caused by skin and dartos adherence or Buck’s fascia attachments. The authors suggest a new surgical approach to solve both problems. If Buck’s fascia involvement is demonstrated by artificial erection then a new diagonal corporal plication suture is [...] described to effectively solve this problem.

Brent W., Snow.

2009-02-01

189

Arthroscopic Absorbable Suture Fixation for Tibial Spine Fractures  

Science.gov (United States)

The purpose of this technical note and accompanying video is to describe a modified arthroscopic suture fixation technique to treat tibial spine avulsion fractures. Twenty-one patients underwent arthroscopic treatment for tibial spine avulsion with our technique; they were clinically and biomechanically evaluated at 2 years' follow-up and showed optimal clinical and radiographic outcomes. Repair with this arthroscopic technique provides a significant advantage in the treatment of type III and IV fractures of the tibial eminence by obtaining arthroscopic fixation within the substance of the anterior cruciate ligament: suture methods based on the avulsed bone fragment are technically impossible, but sutures through the base of the ligament itself provide secure fixation, reducing the risks of comminution of the fracture fragment and eliminating the time for hardware removal. This arthroscopic technique restores the length and the integrity of the anterior cruciate ligament and provides a simplified, reproducible method of treating patients, including young patients, with low hardware costs in comparison to sutures using anchors or other hardware. PMID:24749022

Verdano, Michele Arcangelo; Pellegrini, Andrea; Lunini, Enricomaria; Tonino, Pietro; Ceccarelli, Francesco

2013-01-01

190

Healing of the suture line in the irradiated small intestine  

International Nuclear Information System (INIS)

With the help of data from literature the author goes more deeply into the aetiology, treatment and possible prevention of lesions of the small intestine related to preceding irradiation. In a clinical retrospective study at twenty patients who, after irradiation of the abdominal and pelvic areas, have been submitted to abdominal surgery, the relation is studied between predistion factors for gastrointestinal complications after irradiation, the surgeries applied in case of small-intestine problems and postoperative complications. The third part of the thesis covers an experimental part in which the healing process of suture line in the terminal ileum has been studied after resection and reanastomosis in previously irradiated bowel of the rat. It was investigated whether differences occurred in the healing process of suture line after various periods - 4, 10 and 40 weeks, after irradiation. Also comparison took place with a control group which underwent a similar procedure with the exception of the radiation treatment, which was simulated in this group. In a second experiment it was investigated if the healing process of suture line depends on the type of anastomosis. An end-to-end anastomosis was chosen versus side-to-side anastomosis. Also in this experiment an irradiated group was compared with a control group. Furthermore a method was developed for performing micro-angiographies of the rat intestine in order to demonstrate obliteration of blood vessels in irradiated intestine and to assess neovascularization in the intestinal wall at the suture line. (author). 84 refs.; 18 figs.; 27 tabs

191

21 CFR 878.5030 - Natural nonabsorbable silk surgical suture.  

Science.gov (United States)

21 Food and Drugs 8 2010-04-01...Section 878.5030 Food and Drugs FOOD AND DRUG ADMINISTRATION...with an FDA listed color additive. (b...Class II (special controls). The special control...Sutures; Guidance for Industry and FDA.”...

2010-04-01

192

21 CFR 878.5020 - Nonabsorbable polyamide surgical suture.  

Science.gov (United States)

21 Food and Drugs 8 2010-04-01...Section 878.5020 Food and Drugs FOOD AND DRUG ADMINISTRATION...appropriate FDA listed color additive. Also...Class II (special controls). The special control...Sutures; Guidance for Industry and FDA.”...

2010-04-01

193

21 CFR 878.5035 - Nonabsorbable expanded polytetrafluoroethylene surgical suture.  

Science.gov (United States)

21 Food and Drugs 8 2010-04-01...Section 878.5035 Food and Drugs FOOD AND DRUG ADMINISTRATION...with an approved color additive and may...Class II (special controls). The special control...Sutures; Guidance for Industry and FDA.”...

2010-04-01

194

Obliteration of serrated sutures of a human skull (review  

Directory of Open Access Journals (Sweden)

Full Text Available The review presents information on obliteration of serrated sutures of a human skull. It considers the age-specific variability and sexual dimorphism. The causes of craniostenosis and dependence of cranial form on degree and type of craniostenosis are described

Zaichenko A.A.

2011-09-01

195

Ionizing radiation effect on Brazilian polypropylene  

International Nuclear Information System (INIS)

Polypropylene is a thermoplastic polymer, partially crystalline that can be making in three conformations: atactic, sindiotactic and isotatic. Isotatic polypropylene (PP) that has practical interest, it is employed for manufacture of medical devices, which must be sterilized before using. PP was irradiated with gamma rays from 60 C Co source, whose dose rate was 1.1 and 4.5 kGy/h and the dose range was 0-255 kGy. The irradiations were realized in the presence of air at room temperature. The radiation effects on PP were investigated by IR spectroscopy, electron paramagnetic resonance, viscosimetric average molecular weight (Mw), at 1350 C in decaline and tensile strength at yield (TSy). The PP undergoes radiolytical oxidation up to 100 kGy. The observed radicals at room temperature are: polyenil and peroxyl in the greater concentration. The scission predominates at doses until 100 kGy and above 150 kGy predominates the crosslinking, indicating that the radiation promotes scissions of C - C H3 bonds with such frequency that the sterical hindered gives up existing. At sterilization doses the increase of dose rate promotes the crosslinking. None dose rate effects in Mw was observed at 100 kGy doses. Within 4 days after irradiation end the scissions of backbone remain occurring as consequence of macro radicals oxidation which migrate from the crystalline regions to the amorphous regions. This post-irradiation effect was also observed in macrradiation effect was also observed in macroscopic properties. TSy decays at 25% until about 2 months after the irradiation end. After this time the TSy increases and one year after the irradiation end reaches nearly initial value. The slow process of scission and crosslinking or polymeric backbones entanglement happens. The national PP is protected against radiolytic oxidation adequately during the radiosterilization but is not against backbone scission. After the radiosterilization the PP has a maximum fall of TSy of 25% which is restored after about one year. (author). 50 refs., 36 figs., 12 tabs

196

OLED-polypropylene bio-CD sensor  

Science.gov (United States)

With the goal of developing microfluidic platforms for sensing applications, flash-free micro patterns were embossed in polypropylene surfaces with ultrasonic heating for a biosensing lab-on-CD application. The embossed features were designed to act as reservoirs, valves, and reaction chambers to allow, in combination with a compact sensing platform, the monitoring of analyte levels using a standard PC-CD player. To generate the compact sensor, as an example, we chose the photoluminescence (PL)-based detection of lactate and glucose using an OLED-based sensing platform. Once embossed, the surface energy of the plastic substrate was chemically modified to make it hydrophilic. Reagents, placed in separate reservoirs, were directed through burst valves towards a reaction chamber via CD rotation. Lactate or glucose were monitored by measuring the effect of the related dissolved oxygen level on the PL decay time of an oxygen-sensitive dye, following analyte oxidation catalyzed by a suitable specific oxidase enzyme. The results demonstrate the potential of integrating OLEDs as excitation sources in PL-based sensors with microfluidic CD-based platforms, including for simultaneous multiple analyses.

Vengasandra, Srikanth; Cai, Yuankun; Grewell, David; Shinar, Joseph; Shinar, Ruth

2008-08-01

197

Enhancement of tracer diffusion in polypropylene glycol  

Science.gov (United States)

Tracer diffusion coefficients of camphorquinone in polypropylene glycol (PPG) with molecular weight 400, 1000, 2000, and 4000 have been measured as a function of temperature by using the forced Rayleigh scattering technique. At a fixed temperature, the diffusion coefficient decreases with increasing molecular weight of PPG. A master curve is obtained when the diffusion data are normalized with respect to the viscosity of the PPG liquid. A modified Stokes-Einstein equation for tracer diffusion is used to calculate the effective hydrodynamic radius R*. Below room temperature, R* is found to decrease with decreasing temperature. The decrease of R* is discussed in terms of dynamic heterogeneity and rotation-translation coupling mechanisms. The rotation-translation coupling mechanism has recently been proposed to account for the enhancement of the tracer diffusion coefficient in the molecular liquid in the supercooled state. Comparing R* calculated for CQ in PPG with that for the same tracer in salol in the supercooled state over the same temperature range, one finds that R* in PPG decreases consistently less rapidly than in salol. The result is consistent with the fact that the rotation-translation coupling in PPG is considerably weaker than in liquid salol.

Wang, C. H.; Gong, S. S.

2003-12-01

198

Organoclay Networking in Polypropylene-Clay Nanocomposites  

Science.gov (United States)

We report on networking of organoclays and its influence on the rheology of polypropylene-clay nanocomposites. Samples are blended using either a twin screw extruder (TSE) or a single screw extruder with in situ addition of supercritical CO2 (SCCO2). Blends contain proportional amounts (3:1) of maleic anhydride functionalized PP and organically modified montmorillonite (Cloisite^ 15A, Southern Clay Products) at several clay loadings in a base PP resin (MFI 12 g/10 min at 230 C). Small-amplitude oscillatory shear (SAOS) and steady shear flow were utilized to probe clay morphology with varying annealing time. In SAOS experiments repeated over several hours, the terminal behavior of the TSE samples became increasingly solid-like; in steady shear, the magnitude of the viscosity overshoot increased with annealing time. The single-screw/SCCO2 materials at the same clay loadings differed little rheologically from the neat resin. Finally, network formation kinetics accelerated with increasing temperature, and sufficiently large deformations irreversibly weakened the network structure.

Oberhauser, James; Treece, Mark

2006-03-01

199

Polypropylene matrix composites reinforced with coconut fibers  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Polypropylene matrix composites reinforced with treated coconut fibers were produced. Fibers chemically treated (alkalization-CCUV samples) or mechanically treated (ultrasonic shockwave-CMUV samples) were dried using UV radiation. The goal was to combine low cost and eco-friendly treatments to impro [...] ve fiber-matrix adhesion. Composite samples containing up to 20 vol. (%) of untreated and treated coconut fibers were taken from boxes fabricated by injection molding. Water absorption and mechanical properties were investigated according to ASTM D570-98 and ASTM D638-03, respectively. Electrical characterizations were carried out to identify applications of these composites in the electrical sector. NBR 10296-Electrical Tracking Standard (specific to industry applications) and conductivity measurements were obtained applying 5 kV DC to the samples. CMUV samples containing 5 vol. (%) fiber presented superior tensile strength values (?~28 MPa) compared to the untreated fibers composite (?~22 MPa) or alkali treatment (?~24 MPa). However, CMUV composites containing 10 vol. (%) fiber presented best results for the electrical tracking test and electrical resistivity (3 × 10(7) ?.m). The results suggest that composites reinforced with mechanically treated coconut fibers are suitable for electrical applications.

Maria Virginia, Gelfuso; Pedro Vieira Gurgel da, Silva; Daniel, Thomazini.

2011-09-01

200

Polypropylene and silica short fibers composites  

Directory of Open Access Journals (Sweden)

Full Text Available The mechanical properties of composites strongly depend on the type of filler-polymeric matrix interface. An interface characterized by a strong bond between the filler and the matrix generally results in better mechanical properties. In this work, polypropylene, PP, was used as polymeric matrix and silica short fibers, SF, which are amorphous biogenic silica, were employed as filler. In order to promote a better filler-matrix interfacial adhesion, these fibers were previously modified with vinyltrimethoxysilane. The composites were prepared by extrusion and injection molding processes and their mechanical properties were evaluated according to tensile testing, ASTM D 268, by means a fractional factorial design (25-1. The studied factors included fiber content in the matrix, fiber surface modification, injection flow and testing rate. The composite cryogenic fractured surfaces were investigated by field emission scanning electron microscopy, FESEM. The fiber modification promoted a better fiber-matrix interfacial adhesion, resulting in optimized mechanical properties in relation to the others. In this way, the fiber modification was the most important factor on the mechanical performance of the composites.

Mariana Gava Segatelli

2012-04-01

201

Surface modification of polypropylene based particle foams  

Science.gov (United States)

This paper deals with the modification of the surface properties of expanded polypropylene (EPP). EPP is a semi-hard to soft elastic thermoplastic foam. The characteristic surface of EPP shows process-related steam nozzle imprints and gussets. Therefore EPP does not satisfy the quality requirements for visible automotive applications. In order to meet these demands, plastic surfaces are usually enhanced with functional or decorative coatings, e.g. textiles, plastic films or paint. The coating of plastics with low surface energies such as PP often leads to adhesion problems by reason of the missing polar and functional groups. This paper gives an evaluation of activation and pre-treatment methods of EPP, with the aim to identify the most suitable pre-treatment method. For this purpose five typical surface treatment methods - flame treatment, corona, fluorination, atmospheric and low-pressure plasma - were performed on EPP samples. As a comparison criterion the maximum increase in the adhesion force between a polyurethane-based coating and the modified EPP substrate was selected. Moreover the influence of the selected pre-treatment method on the increase in the total surface energy and its polar component was investigated by the drop shape analysis method. The results showed that the contact angle measurement is a suitable method to determine the polar and disperse fractions of the surface tension of EPP. Furthermore, all performed methods increased the adhesion of EPP.

Schreier, P.; Trassl, C.; Altstädt, V.

2014-05-01

202

Chemical imaging of wood-polypropylene composites.  

Science.gov (United States)

Recent investigations of wood plastic composites have revealed a detrimental effect of using lubricant systems in production. This includes nullifying part or all of the mechanical benefit of using a polar compatibilizer, maleic anhydride polypropylene (MAPP), in the composite formulation. This investigation utilizes lubricants labeled with deuterium in conjunction with Fourier transform infrared (FT-IR) spectroscopy to allow for the separation of individual lubricants from all other material constituents. All of the deuterium labeled lubricants, used without MAPP, revealed their expulsion from the wood interface during crystallization. MAPP coupling agent was found to exist near the wood, but it is unclear if any covalent bonding with the hydroxyl functionality on the wood surface occurred. The addition of zinc stearate lubricants appears to nullify the activity of the anhydride functionality near the wood surface as evidenced by a shift in the FT-IR spectra to the hydrolyzed form of the coupling agent. Most of the additives collect at the edges of the spherulites in mostly amorphous regions of the material. The consequence of this morphology may be a weak interface between crystallites. PMID:16925926

Harper, David P; Wolcott, Michael P

2006-08-01

203

Unravelling the molecular control of calvarial suture fusion in children with craniosynostosis  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Craniosynostosis, the premature fusion of calvarial sutures, is a common craniofacial abnormality. Causative mutations in more than 10 genes have been identified, involving fibroblast growth factor, transforming growth factor beta, and Eph/ephrin signalling pathways. Mutations affect each human calvarial suture (coronal, sagittal, metopic, and lambdoid differently, suggesting different gene expression patterns exist in each human suture. To better understand the molecular control of human suture morphogenesis we used microarray analysis to identify genes differentially expressed during suture fusion in children with craniosynostosis. Expression differences were also analysed between each unfused suture type, between sutures from syndromic and non-syndromic craniosynostosis patients, and between unfused sutures from individuals with and without craniosynostosis. Results We identified genes with increased expression in unfused sutures compared to fusing/fused sutures that may be pivotal to the maintenance of suture patency or in controlling early osteoblast differentiation (i.e. RBP4, GPC3, C1QTNF3, IL11RA, PTN, POSTN. In addition, we have identified genes with increased expression in fusing/fused suture tissue that we suggest could have a role in premature suture fusion (i.e. WIF1, ANXA3, CYFIP2. Proteins of two of these genes, glypican 3 and retinol binding protein 4, were investigated by immunohistochemistry and localised to the suture mesenchyme and osteogenic fronts of developing human calvaria, respectively, suggesting novel roles for these proteins in the maintenance of suture patency or in controlling early osteoblast differentiation. We show that there is limited difference in whole genome expression between sutures isolated from patients with syndromic and non-syndromic craniosynostosis and confirmed this by quantitative RT-PCR. Furthermore, distinct expression profiles for each unfused suture type were noted, with the metopic suture being most disparate. Finally, although calvarial bones are generally thought to grow without a cartilage precursor, we show histologically and by identification of cartilage-specific gene expression that cartilage may be involved in the morphogenesis of lambdoid and posterior sagittal sutures. Conclusion This study has provided further insight into the complex signalling network which controls human calvarial suture morphogenesis and craniosynostosis. Identified genes are candidates for targeted therapeutic development and to screen for craniosynostosis-causing mutations.

Morris C Phillip

2007-12-01

204

Hands-on Activities for understanding Ammonite Sutures  

Science.gov (United States)

There is a lot of primary literature on the origin (and purpose) of complex sutures in ammonites. It is still hotly debated what (if any) benefit complex sutures may have imparted to ammonites. But to start this whole topic (which results in an essay on whether changes in sutures represent a passive or driven trend), I use a set of hands-on exercises that are fun and eye-opening: examining cross-sections through modern nautilus shells, making a play-doh model of an ammonite, and using a Hele-Shaw cell experiment to make complex dendritic shapes. I have found over the years, that students (and my faculty colleagues, too) can easily point out sutures to me on the ammonite fossils in our collection, but they really don't know what they're pointing to (they honestly don't!). So, I split my students (I usually have around 30 in my 200-level Paleobiology course) into teams of three, and we do several things (I do this all in one 4-hour lab, but you could easily do these in separate periods). First, they get an ammonite fossil (always a sediment-filled specimen with the mother of pearl phragmacone at least mostly gone so some of the sutures are clearly visible), and a couple of modern nautilus shells cut in half (I purchase these online from seashellcity.com), and some play-doh (little 2-oz different color tubs I get from Kmart). They have to determine, and then build a model (using play-doh), what they're looking at when they're looking at the ammonite fossils, in particular, the sutures (sans sediment). They are allowed to look stuff up online or in their text. Results are amazing. I've had many teams build a very nice ammonite (usually a tube of play-doh, representing just one chamber with two septal walls at either end of the tube) and then they use a pencil to sketch the sutures on the outside of the phragmacone! I tell them to rethink this and then they work on it more... It's really cool when they finally realize that to make a model of the fossil sutures that they're looking at, they need to peel off their play-doh phragmacone to reveal the sutures (which are just the 1D line at the end of a 2D septal plane) (although the actual 1D 2D thing gets interesting when we delve into the fractal nature of the sutures, see below). Also, the modern nautilus shells beautifully show the difference between growth lines and sutures/septa. So I augment my assessment of their understanding by literally having each student individually trace for me (with their finger) what the suture is on one of the nautilus shells, and what a growth line is (the supplier I use polishes off the periostracum to reveal the mother of pearl with obvious growth lines). I have also taken whole Nautilus shells and buffed off a part of the phragmacone to reveal the edge of the septal wall, which is the exact equivalent of a suture in an ammonite). Then, we run a Hele-Shaw experiment to get viscous fingering (which resembles ammonite sutures). I borrowed this hele-shaw design from the Center for Polymer Studies at Boston University (http://polymer.bu.edu/edu/) Exploring Patterns in Nature. It consists of a pair of ~10-inch square glass plates, one with a hole drilled in it (our Shop makes these for me from standard glass). The hole is a size that fits common plastic tubing (outside diameter) which in turn fits a standard small syringe inside the tubing. The experiment works like this: put a 3 to 5 inch long piece of plastic tube in the hole, but make sure it doesn't stick out the other side (not more than flush), and seal this with some sort of removable sealant; let the sealant stiffen, and clean both plates with windex. Then, on the solid plate, put two stacked thin-section cover slips (I use micro glass little slips) at the corners of the plate, then put the hole-plate with tube up, on top of the cover slips (the inside surfaces need to be very clean), then clip the two plates together with binder clips on each corner. This is a Hele-Shaw cell. Then, with the syringe, inject glycerol between the plates, careful not to put too much in that is squirts out the

Clint Cowan

205

Plasma modification of polypropylene surfaces and its alloying with styrene in situ  

Energy Technology Data Exchange (ETDEWEB)

The treatment of polypropylene surfaces has been studied by dielectric barrier discharges plasma of Ar. The structure and morphology of polypropylene surfaces of Ar plasma modification are characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectrometers and scanning electron microscope. The modified by plasma treatment of iPP (isotactic polypropylene) surface properties have been examined in a determination of free radicals. The modified active surfaces of polypropylene can induce grafting copolymerization of styrene onto polypropylene. The structure of grafting copolymer is characterized and the grafting percent of styrene onto polypropylene is calculated. The homopolymer of styrene can be formed under grafting copolymerization of styrene onto polypropylene, which follows that the alloying of polypropylene with styrene is achieved in situ.

Ma Guiqiu, E-mail: magq@tju.edu.cn [School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300072 (China); Liu Ben; Li Chen; Huang Dinghai; Sheng Jing [School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300072 (China)

2012-01-15

206

Plasma modification of polypropylene surfaces and its alloying with styrene in situ  

International Nuclear Information System (INIS)

The treatment of polypropylene surfaces has been studied by dielectric barrier discharges plasma of Ar. The structure and morphology of polypropylene surfaces of Ar plasma modification are characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectrometers and scanning electron microscope. The modified by plasma treatment of iPP (isotactic polypropylene) surface properties have been examined in a determination of free radicals. The modified active surfaces of polypropylene can induce grafting copolymerization of styrene onto polypropylene. The structure of grafting copolymer is characterized and the grafting percent of styrene onto polypropylene is calculated. The homopolymer of styrene can be formed under grafting copolymerization of styrene onto polypropylene, which follows that the alloying of polypropylene with styrene is achieved in situ.

207

Post irradiation degradation of polypropylene radiation durability of polypropylene stabilized with phenolic stabilizer (II)  

International Nuclear Information System (INIS)

Post irradiation degradation of 60Co gamma irradiated polypropylene stabilized with a phenolic type stabilizer has been followed up to two years after being irradiated. The effectiveness of the stabilizer at various concentrations on the polypropylene samples irradiated up to 150 kGy has been studied and the buildup of carbonyl group in the irradiated samples measured. The obtained results indicated that the oxidative reactions are retarded by addition of stabilizer. The variation of bend strength of the irradiated samples with and without stabilizer was also followed. This property was found to be greatly improved for the stabilized samples irradiated at low doses. However at high doses the effectiveness of the stabilizer declined. In order to correlate these results with the change in the molecular weight of polymer, trends of the change in rheological behaviour such as melt viscosity (?a) and flow behavior parameters (K, n) of both stabilized and unstabilized samples have been investigated. Results showed that at low doses, addition of the stabilizer greatly reduces the extent of chain scission, and therefore, the mechanical properties of the irradiated polymer are retained. (Author)

208

Toughening of polypropylene with ?-nucleated thermoplastic vulcanizates based on polypropylene/ethylene–propylene–diene rubber blends  

International Nuclear Information System (INIS)

Highlights: • We designed and prepared ? nucleated thermoplastic vulcanizates. • We adopted the ? nucleated TPV to toughen polypropylene. • Greatly improved toughness of iPP, limited loss in strength and rigidity was achieved. • A toughening mechanism was proposed. - Abstract: A series of dynamically vulcanized isotactic polypropylene (PP)/ethylene–propylene–diene rubber thermoplastic vulcanizates (TPVs) containing different content of ?-nucleating agent (?-NA) were prepared and introduced into isotactic PP matrix as a toughening agent. The effect of ?-nucleated TPVs (?-TPVs) on the toughness and other properties of PP were studied. Differential scanning calorimetry and wide-angle X-ray diffraction results indicated that the ?-crystallinity and the relative content of ?-phase in ?-TPVs samples and the toughened blends increased with the content of ?-NA increasing. The notched impact strength of PP toughened by ?-TPVs, with limited loss in the tensile strength and rigidity, showed an almost linear increase with increasing ?-NA content. Especially when the content of ?-NA was 0.5 wt%, the impact strength of the toughened blends was ten times more than that of pure PP. The toughening mechanism based on classical rubber toughening mechanisms was discussed and a synergic toughening mechanism was proposed

209

Synthesis, characterization and properties of carbon nanotubes microspheres from pyrolysis of polypropylene and maleated polypropylene  

International Nuclear Information System (INIS)

Microspheres assembled from carbon nanotubes (MCNTs), with the diameters ranging from 5.5 to 7.5 ?m, were synthesized by means of pyrolysis of polypropylene and maleated polypropylene in an autoclave. The characterization of structure and morphology was carried out by X-ray diffractometer (XRD), field-emission scanning electron microscopy (FESEM), (high resolution) transmission electron microscope [(HR)TEM)], selected-area electron diffraction (SAED) and Raman spectrum. As a typical morphology, the possible growth process of MCNTs was also investigated and discussed. The results of nitrogen adsorption-desorption indicate that the Brunauer-Emett-Teller (BET) surface area (140.6 m2/g) of the MCNTs obtained at 600 oC is about twice as that (74.5 m2/g) of carbon nanotubes obtained at 700 oC. The results of catalytic experiment show that MCNTs based catalyst has higher catalytic activity than the carbon nanotubes based catalyst for the preparation of methanol and dimethoxy-ethane by oxidation of dimethyl ether.

210

Influence of Morphology on Electrical Properties of Syndiotactic Polypropylene Compared with Those of Isotactic Polypropylene  

Science.gov (United States)

The influence of morphology on the electrical properties of syndiotactic polypropylene (sPP) has been investigated in comparison with those of conventional isotactic polypropylene (iPP). The evolution of spherulite in sPP occurred at a lower temperature than in iPP, and the size of spherulites in sPP is much smaller than those of iPP, though the number of spherulites increases drastically. The influence of heat treatment on the electrical properties of sPP, such as conductivity and current density-electric field characteristics, is negligible in contrast to iPP, in which the conductivity increased drastically and breakdown strength decreased markedly due to growth of large spherulites upon heat treatment. These results are discussed in terms of morphological change upon heat treatment. As a result, sPP is confirmed to be an excellent candidate for a new insulating polymer for cables which can be used at a much higher operating temperature than that of widely used cables with cross-linked polyethylene (XLPE) (90°C), because of its thermal stability, stable electrical properties even following heating treatment and mechanical flexibility due to the small spherulite size and low crystallinity under any preparation and treatment conditions.

Kim, Dong; Yoshino, Katsumi; Inoue, Takeo; Abe, Masaru; Uchikawa, Nobutaka

1999-06-01

211

Study of Maleic Anhydride Grafted Polypropylene Effect on Resin Impregnated Bamboo Fiber Polypropylene Composit  

Directory of Open Access Journals (Sweden)

Full Text Available Previously, Polyvinyl Alcohol (PVA and phenolic resin were used for resin impregnated bamboo fiber reinforced PP composites which was manufactures for resin impregnated bamboo fiber with polypropylene (PP. Resin impregnation method can show improvement on tensile strength of fiber. However, to reduce the contact surface area and low inter-facial shear strength (IFSS between impregnated resin and matrix, using 40% weight fraction of bamboo fiber in PP matrix, PVA impregnated composites with mean flexural and tensile strength 10% higher than untreated composites were produced butphenolic resin impregnated fiber reinforced composition’s mechanical properties were decreased. In this study maleic anhydride grafted polypropylene (MAPP was used to increase interfacial shear strength between resin impregnated fiber and PP. With 10% MAPP, IFSS between resin impregnated fiber and PP increased more than 100% and reinforced composites. MAPP with untreated, phenolic resin and PVA impregnated cases showed similar mechanical properties. Yet in water absorption test, the PVA treatment with bamboo/PP composites increased water absorption ratio. But with 10% MAPP, matrix PP water absorption ratio decreased like phenolic resin impregnated fiber reinforced composites. 10% MAPP with resin impregnated bamboo fiber reinforced PP composites can improve IFSS, mechanical properties of composite and can decrease water absorption PVA resin impregnated bamboo fiber reinforced composites.

Gibeop Nam

2014-11-01

212

Water Absorption Properties and Morphology of Polypropylene/ Polycarbonate/Polypropylene-graft-Maleic Anhydride Blends  

Directory of Open Access Journals (Sweden)

Full Text Available This study investigates the effect of blending polycarbonate (PC into polypropylene (PP matrix polymer on water absorption properties and morphology. The blends, containing 5-35% of polycarbonate and 5% compatibilizer, were compounded using twin - screw extruder and fabricated into standard tests samples using compression molding. The compatibilizer used was polypropylene-graft-maleic anhydride (PP-g-MA. In water absorption test, specimens were immersed in distilled water at 23 and 100°C. In 23°C immersion, PC showed the highest absorption at 0.362 wt.% while PP was the lowest at 0.064 wt.%. The blends demonstrated transitional absorption value between PP and PC. In 100°C immersion, 90/5/5, 80/15/5 and 70/25/5 compositions (PP/PC/PP-g-MA exhibited lower absorption than PP, indicating enhanced long-term degradation resistance in water compared to PP. Microscopy analysis showed that PC existed as fibers, dispersed throughout PP matrix.

P.S.M. Megat-Yusoff

2013-01-01

213

Production of high melt strength polypropylene by gamma irradiation  

International Nuclear Information System (INIS)

High melt strength polypropylene (HMS-PP) has been recently developed and introduced in the market by the major international producers of polypropylene. Therefore, BRASKEM, the leading Brazilian PP producer, together with EMBRARAD, the leading Brazilian gamma irradiator, and the IPEN (Institute of Nuclear Energy and Research) worked to develop a national technology for the production of HMS-PP. One of the effective approaches to improve melt strength and extensibility is to add chain branches onto polypropylene backbone using gamma radiation. Branching and grafting result from the radical combinations during irradiation process. Crosslinking and main chain scission in the polymer structure are also obtained during this process. In this work, gamma irradiation technique was used to induce chemical changes in commercial polypropylene with two different monomers, Tri-allyl-isocyanurate (TAIC) and Tri-methylolpropane-trimethacrylate (TMPTMA), with concentration ranging from 1.5 to 5.0 mmol/100 g of polypropylene. These samples were irradiated with a 60Co source at dose of 20 kGy. It used two different methods of HMS-PP processing. The crosslinking of modified polymers was studied by measuring gel content melt flow rate and rheological properties like melt strength and drawability. It was observed that the reaction method and the monomer type have influenced the properties. However, the concentration variation of monomer has no effectr has no effect

214

Comparison of life cycle assessment for different volume polypropylene jars  

Directory of Open Access Journals (Sweden)

Full Text Available When deciding what packaging is the most appropriate for a product there are many factors to be considered. One of them is the impact of the packaging on environment. In this work, life cycle inventory and life cycle assessment of two different volume packagings were compared. The data were collected on the types and amounts of materials and energy consumption in the process of packaging and distribution of hand cream packed in polypropylene jars of 200 and 350 mL. Life cycle inventory (LCI and life cycle impact assessment (LCA were calculated. It was found that the total mass flow was higher for the jars of 350 mL. After analyzing individual flows, it was found that in both cycles (polypropylene jars of 200 and 350 mL,the consumption of fresh water was a dominant flow. This fresh water flow is mostly (95% consumed in the injection molding process of manufacturing jars from polypropylene granules. The LCA analysis showed no significant difference in global warming potential between different volume jars. The process that mostly affected global warming was the production of polypropylene jars from polypropylene granules by injection molding for both jar volumes. Judging by the global warming potential, there is no difference of the environmental impact between investigated jars, but considering the mass flow and water consumption, more environmental friendly were the 200 mL jars.

Krki? Nevena M.

2012-01-01

215

Co-60 gamma radiation assisted diffusion of iodine in polypropylene  

International Nuclear Information System (INIS)

Thin films of polypropylene having dimensions 50 mm x 15 mm x 350 ?m were immersed in 1 N iodine solution and then irradiated with Co-60 gamma radiation for the periods of 48, 96 and 144 h at the doses varying from 14.4 to 43.2 kGy. The films were also kept immersed in iodine solution for similar periods but without irradiation. Furthermore, the films were also directly-irradiated with Co-60 gamma radiation for similar periods and doses. The radiation-iodinated, plain-iodinated and directly-irradiated samples were characterized by using various techniques such as weight gain EDS, SEM, FTIR, UV-visible spectroscopy, contact angle and XRD. Weight gain, EDS and SEM collectively reveal that gamma irradiation enhances iodine intake in polypropylene. FTIR, EDS and contact angle measurements indicate that presence of iodine during irradiation resists radiation induced carbonylation of polypropylene. FTIR also shows presence of HOI (Hypoiodous acid) species instead of expected C-I bonds. UV-visible analysis unambiguously shows that presence of iodine enhances radiation induced band gap reduction process of polypropylene. XRD indicates that iodine decreases the crystallinity of polypropylene.

216

Randomized clinical trial comparing manual suture and different models of mechanical suture in the mimicking of bariatric surgery in swine  

Directory of Open Access Journals (Sweden)

Full Text Available Marcos AP Fernandes,1 Bruno MT Pereira,2 Sandra M Guimarães,1 Aline Paganelli,3 Carlos Manoel CT Pereira,1 Claudio Sergio Batista4 1Institute of Obesity and Advanced Video Laparoscopic Surgery of Petropolis, Rio de Janeiro, Brazil; 2Division of Trauma, University of Campinas, São Paulo, Brazil; 3Laboratório de Patologia Micron Cell Diagnóstico, Rio de Janeiro, Brazil; 4Department of Gynecology and Obstetrics, Faculty of Medicine of Petropolis, Rio de Janeiro, Brazil Context and objective: Variations in the ability of surgeons served as motivation for the development of devices that, overcoming individual differences, allow the techniques to be properly performed, and of which the end result was the best possible. Every technique must be reproduced reliably by the majority of surgeons for their results to be adopted and recognized as effective. The aim of this study was to compare the results, from the point of view of anatomic pathology, of manual sutures versus mechanical sutures using different models of linear mechanical staplers, in the procedure of gastroenteroanastomosis and enteroanastomosis in swine. Methods: Thirty-six healthy, adult, male Sus scrofa domesticus pigs, weighing between 20.7 and 25.5 kg, were used. The swine were randomly divided into four groups of nine pigs, according to the type of suture employed: group A, manual suture with Polysorb® 3-0 wire; group B, 80-shear linear stapler (Covidien® Gia 8038-S; group C, 75-shear linear stapler (Ethicon® Tlc 75; and group D, 75-shear linear stapler (Resource® Yq 75-3. A temporal study was established on the seventh postoperative day for histopathological analysis, and the degree of inflammation, fibrosis, and newly formed vessels, as well as the presence or absence of granulation tissue, foreign body granuloma, and necrosis were all evaluated qualitatively and semiquantitatively. The results were analyzed statistically. Results: Observations during the histopathological analysis included the formation of foreign body granuloma in the gastroenteroanastomosis and enteroanastomosis in 88.9% of the swine that underwent manual suture and in none of the swine that underwent stapling. There was also a significant statistical difference among swine from Group A, and those from groups B, C and D regarding the degree of inflammation, being more intense in those swine that underwent manual suture. Conclusion: This study shows that both types of suture promoted proper healing of gastroenteroanastomosis and enteroanastomosis, although there was a higher degree of inflammation and an increased occurrence of foreign body granuloma in swine subjected to manual suture, although there have been similarities in safety, efficiency, and effectiveness between the models of linear mechanical staplers tested during the performance of these anastomoses on swine. Keywords: linear mechanical stapler, stapler, manual suture, surgery, gastroenteroanastomosis, enteroanastomosis, swine, randomized clinical trial

Fernandes MA

2014-02-01

217

Effect of concentration on ultrasonic degradation of chlorinated polypropylene  

International Nuclear Information System (INIS)

The molecular weights of chlorinated polypropylene in toluene solution at various concentrations were determined. Limiting molecular weight of polymers under ultrasonic irradiation could be obtained by the data fitting technique. The fitting accuracy of common kinetic equations for experimental data of chlorinated polypropylene was evaluated. It was found that the fitting results of these kinetic equations were not satisfactory. In order to fit the experimental data better, a new second order kinetic equation was proposed. This equation described well the experimental data. It was found that the fitting results for available experimental data of other polymers using this new equation were better than when using equations in the literature. Therefore, the equation proposed here is a new supplement to the original kinetic equations for polymers under ultrasonic irradiation. For chlorinated polypropylene, the rate of ultrasonic degradation decreased with increasing concentration while the limiting molecular weights increased with increasing concentration

218

Radiation degradation polypropylene molecular weight and melt viscosity change  

International Nuclear Information System (INIS)

Isotactic polypropylene is widely used for production of disposable syringes and for some other single-use medical products. Under irradiation the yield of scission is significantly greater than the yield of cross-linking, resulting in a deterioration of mechanical properties. In addition a slow process of chain autooxidative degradation, following irradiation, usually takes place. Two commercial resins and an additive-free isotactic polypropylene were used for studies in this work. The molecular weight distribution has been measured at high pressure by high temperature liquid chromatography, in order to determine the immediate effect of radiation degradation. This was accompanied by melt viscosity measurements. The data obtained are useful to predict the short and long-term mechanical properties of polypropylene made products, sterilized by ionizing radiation. (author)

219

Radiation degradation of polypropylene molecular weight and melt viscosity change  

International Nuclear Information System (INIS)

Isotactic polypropylene is widely used for the production of disposable syringes and for some other single-use medical products. Under irradiation the yield of degradation is significantly greater than the yield of crosslinking, resulting in a deterioration of mechanical properties. In addition, a slow process of chain autoxidative degradation is usually caused by irradiation. Two commercial resins and an additive free isotactic polypropylene were studied. The molecular weight distribution has been measured by high pressure, high temperature liquid chromatography in order to determine the immediate effect of radiation degradation. This was accompanied by melt viscosity measurements. The data may be useful for predicting the short and long term mechanical properties of polypropylene products sterilized by ionizing radiation. (author)

220

Modification of polypropylene with radiation-treated wood fiber  

International Nuclear Information System (INIS)

The dispersed wood material is used not only as filler for thermosetting polymers but also as a new type of fibrous additive for thermoplastics e.g. polypropylene. Benefit of this additive (filler or reinforcement) is determined by the coupling between the wood and the synthetic resin. Fibrous, dispersed wood material was preirradiated in air, treated with vinyl monomer containing polyester resin and then mixed in polypropylene. Processability of such thermoplastic blends as well as reactivity of the mixed components were followed by measuring energy, absorbed during the kneading of the melt. The vinylmonomer vinylmonomer - polyester additive, activated at higher temperature by the radiation-formed peroxy groups on the wood fiber, results in good processability of the thermoplastic blend, and gives interesting mechanical properties. Calandering, extrusion, pressmoulding and mechanical testing demonstrated good workability and practical value of the polypropylene composite material containing radiation-treated wood fiber. (author)

221

Morphology and mechanical properties of polypropylene-wood flour composites  

Directory of Open Access Journals (Sweden)

Full Text Available The microstructure and mechanical properties of polymer composites based on polypropylene and wood flour modified with monochloroacetic acid were investigated. Scanning electron microscopy and wide-angle X-ray diffraction were used as methods to probe the composite microstructures, while the tensile test was used to measure the physical strength. The wood flour modification was performed at different levels of monochloroacetic acid, ranging from 0.01 to 1 mol, while the modified wood flour was used as filler for polypropylene at 10, 20 and 30 wt.-%. It was found that increasing the monochloroacetic acid fraction influences the microstructure of the composites and leads to more homogeneous products. The introduction of non-modified wood flour decreases the polypropylene crystallization degree, but it improves after introduction of monochloroacetic acid. Physical-mechanical tests showed positive effects on tensile tests and Charpy notched impact strength. The new composites appear to be promising materials for construction purposes.

Vasileva, St.

2006-11-01

222

Facial Asymmetry Correction in Facial Palsy Patients with Silhouette Sutures  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: over the last few decades several techniques static and dynamics, have been performed to improve facial asymmetry and functionality alter suffering facial paralysis. Methods: we present a pilot study to show and evaluate the benefits of a new form of facial suspension, with Silhouette sutures. We performed two patients with total and complete facial palsy due to otical tuberculosis in one case and to parotid carcinoma in the other. Results: one year after surgery, both patients have improved facial asymmetry, mastication and speech production which have lead to a higher self-esteem and major social interaction. Conclusions: static facial suspension with Silhouette sutures is a non invasive alternative to dynamic techniques in patients who don’t want or can’t undergo more complex surgeries.

Juan Fernando Fuentes

2012-01-01

223

Time to failure of biodegradable sutures: a new approach  

Energy Technology Data Exchange (ETDEWEB)

Data on the degradation and lifetime of biodegradable polyglycolic acid (PGA) sutures has been obtained. A new creep rupture technique was used with the samples immersed in a phosphate buffer solution to simulate in vivo fluids. Two groups of sutures were studied. Since irradiation is a convenient method of sterilization, one group consisted of 30 samples irradiated at 5 and 20 Mrad. A second group of 30 unirradiated samples was tested at temperatures from 30 to 45/sup 0/C. Failure occurs much faster at temperatures above 36/sup 0/C, the glass transition temperature for PGA, and for irradiated samples, the rate increasing with dose. At temperatures above glass transition the material becomes more accessible to hydrolysis which is generally accepted as the main mechanism for PGA degradation. Irradiation causes chain scission in non-crystalline regions, the sites responsible for hydrolysis. The failure data has been analysed using the Weibull distribution.

Pourdeyhimi, B.

1987-09-01

224

Time to failure of biodegradable sutures: a new approach  

International Nuclear Information System (INIS)

Data on the degradation and lifetime of biodegradable polyglycolic acid (PGA) sutures has been obtained. A new creep rupture technique was used with the samples immersed in a phosphate buffer solution to simulate in vivo fluids. Two groups of sutures were studied. Since irradiation is a convenient method of sterilization, one group consisted of 30 samples irradiated at 5 and 20 Mrad. A second group of 30 unirradiated samples was tested at temperatures from 30 to 450C. Failure occurs much faster at temperatures above 360C, the glass transition temperature for PGA, and for irradiated samples, the rate increasing with dose. At temperatures above glass transition the material becomes more accessible to hydrolysis which is generally accepted as the main mechanism for PGA degradation. Irradiation causes chain scission in non-crystalline regions, the sites responsible for hydrolysis. The failure data has been analysed using the Weibull distribution. (author)

225

HUESOS SUTURALES EN EL PTERION SUTURAL BONES IN THE PTERION  

Directory of Open Access Journals (Sweden)

Full Text Available Las variaciones de los huesos del cráneo son de interés para la anatomía, antropología física, imagenología y medicina legal. Con el propósito de aportar mayores detalles sobre los huesos suturales que se presentan en el pterion, fueron analizados 205 cráneos secos de individuos brasileños, adultos, de ambos sexos, blancos y no blancos. El hueso sutural fue observado en 31 cráneos (15,1%, localizándose 19 en el lado derecho (61,3%, 8 en el izquierdo (25,8% y 4 en ambos lados (12,9%. Con relación al sexo, 14 estuvieron presentes en cráneos masculinos (45,2% y 17 en femeninos (54,8%. En relación al grupo étnico, 20 eran del grupo blancos (64,5% y 11 de no blancos (35,5%. Las articulaciones de este hueso sutural con los huesos vecinos fueron clasificados en 4 tipos: Tipo I, donde se articuló con los huesos frontal, parietal, ala mayor del esfenoides y temporal, disposición encontrada en 17 cráneos (54,8%; Tipo II, donde se articuló con el parietal, temporal y ala mayor del esfenoides, encontrado en 11 cráneos (35,5%; Tipo III, donde se articuló con el temporal, frontal y ala mayor del esfenoides, observado en 2 cráneos (6,5 % y Tipo IV, donde se articuló con el parietal, frontal y ala mayor del esfenoides, encontrado en 1 cráneo (3,2%. Correlacionando las variables lado, sexo, grupo étnico y hueso sutural, el análisis estadístico reveló que la presencia de estos huesos es significativa en los individuos blancos y en el lado derechoCranium bones variations have been an object of interest for Anatomy, Physical Anthropology, X-Rays and Tomographic Images and Forensic Medicine. The aim of this article is to increase the knowledge of anatomical details about a sutural bone localized in the pterion. We observed 205 cranium of adult cadavers from Brazilian origin, of both sexs, white and non white ethnic group. The sutural bone was found in 31 cranium (15.1%, 19 in the right side (61.3%, 8 in the left side (25.5% and 4 in both sides (12.9%. In respect of the sex, 14 were observed in male cranium (45.2% and 17 in female cranium (54.8%. With respect to the ethnic group, 20 cases (64.5% corresponded to white individuals and 11 (35.5% to non white. Sutural bone joints with the next bones, were classified in four groups: Type I, the sutural bone joined with the frontal, parietal, greater wing of the sphenoid and temporal bones, this type was observed in 17 cranium (54.8%; Type II, it joined with the greater wing of the sphenoid, parietal and temporal bones, this type was observed in 11 cranium (35.5%; Type III, the sutural bone joined with the greater wing of the sphenoid, temporal and frontal bones, this type was observed in only 2 cranium (6.5% and Type IV, it joined with the greater wing of the sphenoid, parietal and frontal bones, this type was observed in only 1 cranium (3.2%. The statistical analysis of the different variables considered in this article showed that the presence of these bones is significative in white individuals and also in the right side in respect of all specimens

M. T. T. Braga

2000-01-01

226

HUESOS SUTURALES EN EL PTERION / SUTURAL BONES IN THE PTERION  

Scientific Electronic Library Online (English)

Full Text Available Las variaciones de los huesos del cráneo son de interés para la anatomía, antropología física, imagenología y medicina legal. Con el propósito de aportar mayores detalles sobre los huesos suturales que se presentan en el pterion, fueron analizados 205 cráneos secos de individuos brasileños, adultos, [...] de ambos sexos, blancos y no blancos. El hueso sutural fue observado en 31 cráneos (15,1%), localizándose 19 en el lado derecho (61,3%), 8 en el izquierdo (25,8%) y 4 en ambos lados (12,9%). Con relación al sexo, 14 estuvieron presentes en cráneos masculinos (45,2%) y 17 en femeninos (54,8%). En relación al grupo étnico, 20 eran del grupo blancos (64,5%) y 11 de no blancos (35,5%). Las articulaciones de este hueso sutural con los huesos vecinos fueron clasificados en 4 tipos: Tipo I, donde se articuló con los huesos frontal, parietal, ala mayor del esfenoides y temporal, disposición encontrada en 17 cráneos (54,8%); Tipo II, donde se articuló con el parietal, temporal y ala mayor del esfenoides, encontrado en 11 cráneos (35,5%); Tipo III, donde se articuló con el temporal, frontal y ala mayor del esfenoides, observado en 2 cráneos (6,5 %) y Tipo IV, donde se articuló con el parietal, frontal y ala mayor del esfenoides, encontrado en 1 cráneo (3,2%). Correlacionando las variables lado, sexo, grupo étnico y hueso sutural, el análisis estadístico reveló que la presencia de estos huesos es significativa en los individuos blancos y en el lado derecho Abstract in english Cranium bones variations have been an object of interest for Anatomy, Physical Anthropology, X-Rays and Tomographic Images and Forensic Medicine. The aim of this article is to increase the knowledge of anatomical details about a sutural bone localized in the pterion. We observed 205 cranium of adult [...] cadavers from Brazilian origin, of both sexs, white and non white ethnic group. The sutural bone was found in 31 cranium (15.1%), 19 in the right side (61.3%), 8 in the left side (25.5%) and 4 in both sides (12.9%). In respect of the sex, 14 were observed in male cranium (45.2%) and 17 in female cranium (54.8%). With respect to the ethnic group, 20 cases (64.5%) corresponded to white individuals and 11 (35.5%) to non white. Sutural bone joints with the next bones, were classified in four groups: Type I, the sutural bone joined with the frontal, parietal, greater wing of the sphenoid and temporal bones, this type was observed in 17 cranium (54.8%); Type II, it joined with the greater wing of the sphenoid, parietal and temporal bones, this type was observed in 11 cranium (35.5%); Type III, the sutural bone joined with the greater wing of the sphenoid, temporal and frontal bones, this type was observed in only 2 cranium (6.5%) and Type IV, it joined with the greater wing of the sphenoid, parietal and frontal bones, this type was observed in only 1 cranium (3.2%). The statistical analysis of the different variables considered in this article showed that the presence of these bones is significative in white individuals and also in the right side in respect of all specimens

M. T. T., Braga; C., Gabrielli; A, De Souza; C. F. S., Rodrigues; J. C., Marino.

227

Silicon oxide diffusion barrier coatings on polypropylene  

International Nuclear Information System (INIS)

In this study the influence of process conditions for the plasma-enhanced chemical vapor deposition of SiOx diffusion barrier coatings on polypropylene (PP) is investigated and compared to results obtained on polyethylene terephthalate (PET). It was observed that the thermal load during deposition is much more crucial in the case of PP. If the thermal load is not the limiting factor, the composite parameter (CP) energy input per mass of precursor showed to be valuable to describe plasma conditions at constant oxygen to monomer ratio. Low oxygen transmission rates (OTRs) of 5.1 ± 3.6 and 0.3 ± 0.1 cm3/m2day/atm were achieved on PP and PET foil, respectively, for an optimal CP of 4.1 x 105 J/g. Fourier transform infrared (FTIR) spectroscopy revealed that low carbon and silanol content is necessary for good barrier performance. Low RF power, necessary to reduce thermal load on PP, can be compensated by increasing the oxygen to monomer ratio. For favorable plasma conditions, the dependence of the OTR on the coating thickness follows a similar trend for both substrate materials with a critical thickness of approximately 12 nm. The residual permeation can be correlated to the defect density at each stage of film growth by means of a simple correlation. Further support for permeation through defects is found by the activated rate theory, since the apparent activation energy of oxygen permeation is below typical values of amorphoution is below typical values of amorphous glasses and remains unchanged due to the deposition of SiOx on both substrates.

228

Meaningful assessment method for laparoscopic suturing training in augmented reality:  

OpenAIRE

To be an effective training tool, a laparoscopic simulator has to provide metrics that are meaningful and informative to the trainee. Time, path length and smoothness are often used parameters, but are not very informative on the quality of the performance. This study aims to validate a newly developed assessment method for laparoscopic suturing on the ProMIS augmented reality simulator, and compares it with scores of objective observers. Methods Twenty-four participants practised their ...

Botden, S. M. B. I.; Hingh, I. H. J. T.; Jakimowicz, J. J.

2009-01-01

229

Histological findings in sutured and fibrin-glued microvascular anastomosis.  

Science.gov (United States)

A new method of microvascular anastomosis is presented. A sufficient sutureless telescoping anastomosis was achieved using fibrin adhesive (Tissucol, Immuno GmbH, Heidelberg, FRG) and a Fogarty embolectomy catheter (American Hospital Supply, Deutschland GmbH, Munich, FRG) as an internal splint in the abdominal aorta of Sprague-Dawley rats. The main advantage of this technique is its short application time. Histological examinations mostly showed accelerated healing compared with sutured anastomosis. PMID:6385941

Brunner, F X

1984-01-01

230

Arthroscopic Absorbable Suture Fixation for Tibial Spine Fractures  

OpenAIRE

The purpose of this technical note and accompanying video is to describe a modified arthroscopic suture fixation technique to treat tibial spine avulsion fractures. Twenty-one patients underwent arthroscopic treatment for tibial spine avulsion with our technique; they were clinically and biomechanically evaluated at 2 years' follow-up and showed optimal clinical and radiographic outcomes. Repair with this arthroscopic technique provides a significant advantage in the treatment of type III and...

Verdano, Michele Arcangelo; Pellegrini, Andrea; Lunini, Enricomaria; Tonino, Pietro; Ceccarelli, Francesco

2013-01-01

231

Arthroscopic Suture Bridge Fixation of Tibial Intercondylar Eminence Fractures  

OpenAIRE

Tibial intercondylar eminence fractures that are displaced and non-reducible require open or arthroscopically assisted repair. Ideally, fracture reduction and fixation would be performed with a technique that has low morbidity, allows easy visualization and reduction, provides firm fixation, does not violate the proximal tibial physis, avoids metal hardware, and does not require a second procedure for implant removal. The suture bridge technique, used in the shoulder for rotator cuff tears an...

Sawyer, Gregory A.; Hulstyn, Michael J.; Anderson, Brett C.; Schiller, Jonathan

2013-01-01

232

Facial Asymmetry Correction in Facial Palsy Patients with Silhouette Sutures  

OpenAIRE

Introduction: over the last few decades several techniques static and dynamics, have been performed to improve facial asymmetry and functionality alter suffering facial paralysis. Methods: we present a pilot study to show and evaluate the benefits of a new form of facial suspension, with Silhouette sutures. We performed two patients with total and complete facial palsy due to otical tuberculosis in one case and to parotid carcinoma in the other. Results: one year after surgery, both patients ...

Juan Fernando Fuentes; Lluisa Torrent; Ricard Palao; María Luisa Navarrete; Mireia González

2012-01-01

233

Efficacy of b-lynch brace suture in postpartum haemorrhage  

International Nuclear Information System (INIS)

Massive uncontrolled haemorrhage after childbirth is the leading cause of maternal death in developing countries. Postpartum haemorrhage is traditionally defined as blood loss of more than 500 ml after vaginal delivery and more than 1000 ml after caesarean section, but intraoperative estimation of blood loss is inaccurate. Uterine atony alone accounts for 75 - 90% of PPH. To estimate the effectiveness and safety of B-Lynch brace Suture in the management of primary postpartum haemorrhage (PPH). (author)

234

Complications of bioabsorbable suture anchors in the shoulder.  

Science.gov (United States)

The development of the suture anchor has played a pivotal role in the transition from open to arthroscopic techniques of the shoulder. Various suture anchors have been manufactured that help facilitate the ability to create a soft tissue to bone repair. Because of reported complications of loosening, migration, and chondral injury with metallic anchors, bioabsorbable anchors have become increasingly used among orthopaedic surgeons. In this review, the authors sought to evaluate complications associated with bioabsorbable anchors in or about the shoulder and understand these in the context of the total number of bioabsorbable anchors placed. In 2008, 10 bioabsorbable anchor-related complications were reported to the US Food and Drug Administration. The reported literature complications of bioabsorbable anchors implanted about the shoulder include glenoid osteolysis, synovitis, and chondrolysis. These potential complications should be kept in mind when forming a differential diagnosis in a patient in whom a bioabsorbable anchor has been previously used. These literature reports, which amount to but a fraction of the total bioabsorbable anchors implanted in the shoulder on a yearly basis, underscore the relative safety and successful clinical results with use of bioabsorbable suture anchors. Product development continues with newer composites such as PEEK (polyetheretherketone) and calcium ceramics (tricalcium phosphate) in an effort to hypothetically create a mechanically stable construct with and improve biocompatibility of the implant. Bioabsorbable anchors remain a safe, reproducible, and consistent implant to secure soft tissue to bone in and about the shoulder. Meticulous insertion technique must be followed in using bioabsorbable anchors and may obviate many of the reported complications found in the literature. The purpose of this review is to provide an overview of the existing literature as it relates to the rare complications seen with use of bioabsorbable suture anchors in the shoulder. PMID:21856927

Dhawan, Aman; Ghodadra, Neil; Karas, Vasili; Salata, Michael J; Cole, Brian J

2012-06-01

235

Left atrial appendage occlusion by invagination and double suture technique  

OpenAIRE

Left atrial appendage (LAA) plays a crucial role as a source of atrial thrombus in patients with atrial fibrillation (AF). Thus, the need to close LAA becomes evident in patients with AF who undergo concomitant mitral valve surgery. Unfortunately, it has been reported a high rate of unsuccessful LAA occlusion, regardless of the technique employed.We propose a safe and simple method for LAA occlusion consisting in invagination of the appendage into the left atrium, followed by two sutures (pur...

Hernandez-estefania, Rafael; Levy Praschker, Beltran; Bastarrika, Gorka; Rabago, Gregorio

2011-01-01

236

Arthroscopic Suture Bridge Fixation of Tibial Intercondylar Eminence Fractures  

Science.gov (United States)

Tibial intercondylar eminence fractures that are displaced and non-reducible require open or arthroscopically assisted repair. Ideally, fracture reduction and fixation would be performed with a technique that has low morbidity, allows easy visualization and reduction, provides firm fixation, does not violate the proximal tibial physis, avoids metal hardware, and does not require a second procedure for implant removal. The suture bridge technique, used in the shoulder for rotator cuff tears and greater tuberosity fracture repair, has the ability to produce high contact pressures with rigid fixation. We describe an all-inside and all-epiphyseal arthroscopic suture bridge technique for tibial intercondylar eminence fracture repair performed with PushLock anchors (Arthrex, Naples, FL). One or 2 anchors preloaded with No. 2 FiberWire (Arthrex) are placed in the posterior fracture bed, followed by fracture reduction. The suture limbs are shuttled through and around the anterior cruciate ligament and over the fracture fragment in crossing fashion and are secured by use of additional anchors placed at the anteromedial and anterolateral fracture margin. The anchors are placed obliquely to avoid the proximal tibial physis in the pediatric population. Anatomic reduction and secure fixation allow more aggressive rehabilitation and faster restoration of joint function. PMID:24400173

Sawyer, Gregory A.; Hulstyn, Michael J.; Anderson, Brett C.; Schiller, Jonathan

2013-01-01

237

Tectonics of the South Anyui Suture, Northeastern Asia  

Science.gov (United States)

The South Anyui Suture separates the structures of the Chukotka and Verkhoyansk-Kolyma Fold Areas. The suture consists of ophiolites, island-arc rocks, deformed Upper Triassic and Upper Jurassic-Lower Cretaceous turbidites, and accretionary-type terrigenous melange with blocks of oceanic crust. Two main stages in the geological history of the South Anyui Suture are distinguished: (1) the oceanic stage (Paleozoic-onset of Late Jurassic), when the vast Protoarctic ocean with ensimatic island arcs existed, and (2) the collisional stage (Volgian Age-Early Cretaceous) that started with the transformation of the ocean into the residual and closing South Anyui turbidite basin and was completed by the formation of a fold-nappe structure in the Hauterivian-Barremian. In the course of collision, the oceanic and island complexes were thrust to the north over the passive margin of Chukchi Peninsula. The thrusting was followed by the formation of south-vergent retrocharriages and then by final strike-slip faulting. In the Aptian-Albian, collision gave way to extension with the formation of metamorphic cores and superposed orogenic basins.

Sokolov, S. D.; Tuchkova, M. I.; Ganelin, A. V.; Bondarenko, G. E.; Layer, P.

2015-01-01

238

ADJUSTABLE SUTURE STRABISMUS SURGERY: A REVIEW OF 850 CASES  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose. The aim of the study is to investigate the relationship between the different kinds of squint and the adjustament re- quired in post-op. Methods. Our personal case histories concerns 850 patients that underwent adjustable suture strabismus surgery during the last ten years, examinated in our Department of Ophtalmology over the period 2000-2009. The same surgeon (G.L. performed adjustable suture strabismus surgery as routine duties, whether on horizontal or vertical rectus muscles, but never on oblique muscles. Adjustments were always performed in the 24 postoperative hours. With regard to the relationship between previous surgeries, and requested regulation: 669 cases not underwent previous sur- gery; 181 cases peviously underwent surgery one or more times. results. First we seek for the statistical significant difference between the various results found, computing X2, ? and the rel- ative risk. We can conclude by saying that who made a vertical muscle squint surgery presents a relative risk of 3 times greater to take hypocorrection rather than hypercorrection and that who made before squint surgery presents a relative risk of 2,72 times greater to take regulation. Conclusions. We predicted this result because it confirms that the use of adjustable suture is the more frequent as the muscle fibrosis is the more significant. And the fibrosis is an usual outcome of previous squint surgery.

M.E. Latronico

2010-11-01

239

Syneture stainless STEEL suture. A collective review of its performance in surgical wound closure.  

Science.gov (United States)

Syneture (division of U.S. Surgical, division of Tyco Healthcare, Norwalk, Connecticut, USA) STEEL sutures are monofilament stainless steel sutures composed of 316L stainless steel conforming to ASTM Standard F138 grade 2 (" Stainless steel bar and wire for surgical implant"). STEEL sutures meet all requirements established by the United States Pharmacopeia (USP) for nonabsorbable surgical sutures. Steel sutures are for use in abdominal wound closure, intestinal anastomosis, hernia repair, sternal closure, and skin closure. They are attached to the following types of surgical needles: Roto-Grip Needles and SCC Needle. The sutures and needles are packaged in a Mylar/Tyvek outer envelope. The purposes of this clinical review are two fold. First, we will report the performance of the Syneture STEEL suture product in the largest studies of suture performance ever reported in the literature. In addition, we will provide comprehensive information from the surgical literature that highlights the unique benefits of stainless steel sutures for the following wound closure techniques: sternal fixation, abdominal wound repair, inguinal hernia repair, and skin wound closure. Consorta Inc. (Rolling Meadows, Illinois), a leading healthcare resource management group purchasing organization, and Syneture, jointly with a clinician task force, designed a reproducible surgical evaluation program for needles and sutures in a large cooperative of healthcare systems. Because of the subjective nature of the more commonly used suture selection techniques, a nonexperimental observational study approach was designed to replace perception of performance characteristics with actual clinical experience. In a report involving 19 Consorta shareholder hospitals, they discussed the preliminary part (Phase I) of a large nonexperimental observational study of the clinical performance of surgical needles and sutures. Performance characteristics of the sutures and needles produced by Syneture that were evaluated in 3407 surgical procedures included packaging/ease of opening, needle strength and sharpness, tissue drag, knot security, tensile strength, clinically acceptable determinations, and clinically unacceptable determinations. In this preliminary study, the surgeons concluded that the needles and sutures were clinically acceptable in 98.1% of the evaluations. Armed with this favorable experience, we wanted to expand this observational study to an entirely new group of shareholder hospitals that had a larger number of participating hospitals (Phase I, 19 hospitals; Phase II, 42 hospitals). This more than doubling of hospital observational base dramatically increased the number of patients and performance evaluations. In the Phase II expanded program involving 42 hospitals, the number of patients (8939) and the number of evaluations (25,545) were more than twofold the preliminary study. In the phase I multicentric evaluation of Syneture surgical sutures, the performance of 9266 sutures was evaluated. Of these performance evaluations, 130 evaluations focused on Syneture STEEL sutures. The surgeons were especially pleased by the performance of this suture product, with 129 Syneture STEEL products being judged as clinically acceptable in their performance. Only one Syneture STEEL suture was judged to be unacceptable in its performance, resulting in a 99.2% acceptability rating. In the expanded phase II evaluation of Syneture suture products, the performance evaluation involved 25,545 surgical suture evaluations. The performance of Syneture STEEL sutures was judged in 215 cases. Of these product performance evaluations, 207 were judged to be clinically acceptable in their performance (96.3%). It is important to emphasize that the phase I and phase II observational studies evaluated the performance of other sutures besides monofilament steel sutures. These comprehensive suture and needle performance evaluations included the following additional sutures: Plain Gut, Mild Chromic Gut, Chromic Gut, DEXON II, DEXON S, MAXON, BIOSYN, SOFSILK, SURGILON, BRAL

Edlich, Richard F; Drake, David B; Rodeheaver, George T; Winters, Kathryne L; Greene, Jill A; Gubler, K Dean; Long, William B; Britt, L D; Winters, Samuel P; Scott, Christine C; Lin, Kant Y

2006-01-01

240

Induced modifications in the irradiated polypropylene with accelerated electrons  

International Nuclear Information System (INIS)

The polypropylene is a polymers that undergoes through degradation and crosslinking effects whenever irradiated. Polypropylene samples in different physical shapes (reactor pellets, extruded pellets, and injected plaques) were irradiated with doses ranging from 2,5 to 8,0 KGy. The results of intrinsic viscosity, melt flow index, and amount of antioxidants before and after irradiation were compared. The results showed the effects of irradiation dose, irradiation atmosphere, and stabilization system on the polymer degradation and crosslinking. The analysis of the flow curves of the irradiated and non irradiated materials with the same melt flow index showed that the flow properties differ considerably. (author)

241

Investigation into effects of environmental radiation on polypropylene bags  

International Nuclear Information System (INIS)

Polypropylene woven bags were exposed to environmental conditions over a period of time. Samples were removed from woven bags and the tensile properties examined using an extensometer. Molar mass changes were monitored by dilute viscosity measurements. The concentration of the stabilisers was determined using UV spectroscopy. This study established the behaviour of polypropylene tapes under environmental conditions. The mechanical properties of the samples were found to deteriorate with exposure time. Also, the amount of stabiliser reduced with aging time whilst the molar mass increased suggesting crosslinking of the material occurring. The results of the study suggest that there was no difference in the performance between the stabilised and the unstabilised samples. (author)

242

Polypropylene—Polyethylene Melts: Phase Structure Determination by Rheology  

Science.gov (United States)

Using dynamic moduli and transmission electron microscopy images the phase structure of polypropylene-polyethylene melts was studied. Blends consisting of 80% base material (polypropylene-homopolymer or ethylene-propylene copolymer) and of 20% modifier polymer (a C2/C8-elastomer, a linear low density polyethylene or a high density polyethylene) forming a two-phase structure in the melt were investigated. The influence of the viscosity ratio and the interfacial tension on the particle size of the inclusions was investigated. Both factors can be determined from dynamic moduli by using the emulsion model of Palierne [1] to calculate the interfacial tension.

Kock, Cornelia; Schausberger, A.; Aust, N.; Gahleitner, M.; Ingolic, E.

2008-07-01

243

Synthesis of Polypropylene Fiber/Hydrated Iron Oxide Nanocomposite Adsorbent  

Directory of Open Access Journals (Sweden)

Full Text Available Composite adsorbent based on the polypropylene fibers with chemically bound nanoparticles of hydrated iron (III oxide were synthesized by two-stage experiment: radiation-induced graft polymerization of acrylic acid onto the surface of polypropylene fibers followed by the in-situ formation of hydrated iron oxide nanoparticles and their stabilization on the fibers’ surface within the grafted layer. SEM and XRD investigations revealed a compact homogeneous layer of amorphous nanoaggregates (70-100 nm formed by iron hydroxide on the fibers’ surface. The synthesized nanocomposite fibers were stable in the aggressive medium for a long time and exhibited good adsorption properties for uranyl ions.

Bondar I.V.

2013-09-01

244

Shrinkage of polypropylene fibre reinforced high strength concrete  

OpenAIRE

In this diploma paper we deal with the analysis of high strength concrete, micro-reinforced with polypropylene fibers. We used four different lengths of polypropylene fibers: 6mm, 12 mm, 18 mm and 30 mm. The share of fibers in each concrete mixture is 0.5 % of the total volume. With high strength concretes autogenous shrinkage is very intensive, so the first day we measured it electronically with dial gauges. Later we measured the shrinking with a mobile displacement transducer. We measured a...

Zajec, Matija

2012-01-01

245

Preparation of organophilic clays and polypropylene nano composites  

International Nuclear Information System (INIS)

Polypropylene/montmorillonite nano composites were prepared by the melt intercalation technique. The clay was organically modified with different quaternary ammonium salts to obtain the organo clay. The modified clays with the quaternary ammonium salts were introduced in a polypropylene matrix with 3 wt. % of clay. The interlayer distance (d001) of the clay particles were obtained by X- ray diffraction and the thermal stability of the systems were investigated by thermogravimetry. The organo clay presence in the polymer matrix increased the degradation temperature in relation to the pure polymer. (author)

246

Influence of different types of surgical suture materials on mehanical damage of oral mucosa  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction. Throughout history many kinds of different suture materials have been used for closing and suturing surgical wounds. Medical literature describes four basic characteristics of suture material: knot safety, tensile strength, tissue reaction and wound safety. The tissue reaction is reflected in an inflammatory response, which, though minimal, occurs during first two to seven days after implanting suture into the tissue. The aim of this research was to investigate whether different suture materials affect the development of decubital damage of oral mucosa, which to a great extent can compromise the process of wound healing. Material and methods. The investigation was designed as a prospective clinical study including 150 patients of both genders, aged between 25 and 60. The patients were distributed into three groups of 50 persons. The suture Black Silk was used in the first group, designated as a control group. Nylon and Vicril were used in the second and third group, i.e. experimental groups, respectively. Decubital damage of the surrounding soft tissues was the main parameter for monitoring the effects of selected suture materials on the oral mucosa. Conclusion. The comparison of results obtained for the investigated suture materials after suturing oral mucosa revealed that certain advan­tage could be given to synthetic monofilament suture materials

Mirkovi? Siniša

2011-01-01

247

The Jinshajiang Ailaoshan Suture Zone, China: tectonostratigraphy, age and evolution  

Science.gov (United States)

The Jinshajiang Suture Zone is important for enhancing our understanding of the evolution of the Paleo-Tethys and its age, tectonic setting and relationship to the Ailaoshan Suture Zone have long been controversial. Based on integrated tectonic, biostratigraphic, chemostratigraphic and isotope geochronological studies, four tectono-stratigraphic units can be recognized in the Jinshajiang Suture Zone: the Eaqing Complex, the Jinshajiang Ophiolitic Melange, the Gajinxueshan "Group" and the Zhongxinrong "Group". Isotope geochronology indicates that the redefined Eaqing Complex, composed of high-grade-metamorphic rocks, might represent the metamorphic basement of the Jinshajiang area or a remnant micro-continental fragment. Eaqing Complex protolith rocks are pre-Devonian and probably of Early-Middle Proterozoic age and are correlated with those of the Ailaoshan Complex. Two zircon U-Pb ages of 340±3 and 294±3 Ma, separately dated from the Shusong and Xuitui plagiogranites within the ophiolitic assemblage, indicate that the Jinshajiang oceanic lithosphere formed in latest Devonian to earliest Carboniferous times. The oceanic lithosphere was formed in association with the opening and spreading of the Jinshajiang oceanic basin, and was contiguous and equivalent to the Ailaoshan oceanic lithosphere preserved in the Shuanggou Ophiolitic Melange in the Ailaoshan Suture Zone; the latter yielded a U-Pb age of 362±41 Ma from plagiogranite. The re-defined Gajinxueshan and Zhongxinrong "groups" are dated as Carboniferous to Permian, and latest Permian to Middle Triassic respectively, on the basis of fossils and U-Pb dating of basic volcanic interbeds. The Gajinxueshan "Group" formed in bathyal slope to neritic shelf environments, and the Zhongxinrong "Group" as bathyal to abyssal turbidites in the Jinshajiang-Ailaoshan back-arc basin. Latest Permian-earliest Middle Triassic synorogenic granitoids, with ages of 238±18 and 227±5-255±8 Ma, respectively, and an Upper Triassic overlap molasse sequence, indicate a Middle Triassic age for the Jinshajiang-Ailaoshan Suture, formed by collision of the Changdu-Simao Block with South China.

Wang, Xiaofeng; Metcalfe, I.; Jian, Ping; He, Longqing; Wang, Chuanshan

2000-12-01

248

Surface modification of polypropylene and compatibilization of interfaces in incompatible blends of polypropylene with polystyrene by plasma of CO2  

International Nuclear Information System (INIS)

The effect of surface modification of polypropylene (PP) film is induced by CO2 plasma in this study. The change in chemical structures on the surface of PP film is characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR). The polarity of modified surface of PP film is investigated by contact angle method. The compatibilization of interfaces between polypropylene and polystyrene phases in incompatible blends is studied by the treatment of plasma of CO2. Transition layer thickness is measured by small angle light scattering (SALS).

249

Propriedades mecânicas de nanocompósitos de polipropileno e montmorilonita organofílica Mechanical properties of polypropylene and organophilic montmorillonite nanocomposites  

Directory of Open Access Journals (Sweden)

Full Text Available Neste trabalho foram preparados nanocompósitos de polipropileno e montmorilonita organofílica comercial Cloisite 20A em concentrações de 2,5%, 5,0%, 7,5% e 10,0% e polipropileno graftizado com anidrido maleico como agente compatibilizante pela técnica de intercalação do fundido em extrusora de dupla rosca. Os materiais obtidos foram caracterizados por difração de raios x, ensaios de tração e impacto de acordo com as normas ASTM D638 e D256, respectivamente. Os resultados de difração de raios x indicaram a formação de nanocompósitos com estruturas parcialmente esfoliadas ou intercaladas, dependendo da composição, que proporcionaram aumento do módulo de elasticidade enquanto as propriedades de resistência ao impacto não foram satisfatórias.Nanocomposites of polypropylene and commercial montmorillonite organophilic Cloisite 20A containing 2.5%, 5%, 7.5% and 10% of clay with polypropylene-graft-maleic anhydride as coupling agent were prepared through the melt intercalation by twin-screw extruder. The materials were characterized by x-ray diffraction, tensile and impact properties according to ASTM D638 and D256 test methods, respectively. The x-ray diffraction results showed exfoliated or intercalated structures for different concentrations of the clay. The tensile modulus improved with the increase of the amount of the clay while the impact strength showed unsatisfactory results.

Lucilene B. de Paiva

2006-06-01

250

Use of Cellulose-Containing Fillers in Composites with Polypropylene  

OpenAIRE

The composites, containing recycled polypropylene and fillers, obtained from different lignocellulosics by the thermocatalytic destruction method, were investigated. Birch sawdust, newsprint wastes, cotton residues and wood bleached sulphate pulp were used as raw materials for obtaining fillers. The indices of mechanical properties (tensile strength, modulus of elasticity, deformation at break, shear modulus, toughness, twisting moment) of the composites' samples were determined. It has been ...

Tavroginskaya, Marina; Valenkov, Andrej; Shapovalov, Viktor; Shulga, Galia; Chernyavskaya, Svetlana; Laka, Marianna

2011-01-01

251

CRUDE PALM OIL AS A BIOADDITIVE IN POLYPROPYLENE BLOWN FILMS  

Directory of Open Access Journals (Sweden)

Full Text Available Growing public concern about environment and potential risks to health in the polymer and plasticizer industry promises to increase the market for a safer alternative plasticizer such as a vegetable oil-based agent. The purpose of this study was to investigate the potential of crude palm oil as a bio-additive in polypropylene blown films. The polypropylene was blended with 1%, 3%, and 5% dosages of CPO using a twin screw extruder. The extruded samples were blown using the blown thin film technique. Mechanical, physical, and morphological properties were characterized. Modifying polypropylene with CPO showed good enhancement in the mechanical properties of the polypropylene. Tensile strength, elongation at break, impact strength, and tear strength all increased. The scanning electron microscopy photographs of the CPO-modified PP clearly supported the results from the mechanical strength tests. The presence of CPO in the PP matrices decreased the density and increased the melt flow rate. These findings contribute new knowledge to the additives area and give important implications for designing and manufacturing polymer packaging materials.

Emiliana Rose Jusoh,

2012-01-01

252

Polypropylene nanocomposites: effect of coupling agent on structure and properties.  

Czech Academy of Sciences Publication Activity Database

Dresden : Max Planck Institute for the Physic of Complex Systems, 2005. [MPG-MOEL– Symposium: Science and Art in Europe, Polymers: Materials in Nature and in Advanced Technologies. 23.5.2005-25.5.2005, Dresden] R&D Projects: GA AV ?R(CZ) IBS4050351 Keywords : polypropylene * nanocomposites * melt-compounding Subject RIV: CD - Macromolecular Chemistry

Kotek, Ji?í; Kelnar, Ivan; Studenovský, Martin

253

Nanogels and microgels of polypropylene obtained by gamma irradiation  

International Nuclear Information System (INIS)

In preparation of HMS-PP (polypropylene modified by gamma irradiation), we use the iPP (isotactic polypropylene) in pellets, which was packaged in plastic container an then irradiated with 60Co gamma source containing acetylene pressure of 110 kPa and at doses of 5, 12.5 and 20 kGy. The gel fraction of the samples was determined by extraction of soluble components in boiling xylene for 12 hours at 138 deg C. The soluble portion of the sample was decanted with the total volatilization of xylene at room temperature (25 deg C) and deposited on glass slides. These samples were characterized by: scanning electron microscopy, scanning electron microscope with field emission. In this study the morphology, we obtained the formation of microgels with a higher incidence of polypropylene in PP 12.5 kGy and 20 kGy. Also it was found nanoscale structures of gels of polypropylene (nanogels) in samples of PP 12.5 kGy. (author)

254

Rheological behaviour of metallocene polypropylenes prepared by reactive extrusion process.  

Czech Academy of Sciences Publication Activity Database

Lisbon : European Society of Rheology, 2012. s. 394. [International Congress on Rheology /16./. 05.08.2012-10.08.2012, Lisbon] R&D Projects: GA ?R GA103/09/2066 Keywords : metallocene polypropylene * constitutive modelling * differential models Subject RIV: BK - Fluid Dynamics

Pivokonský, Radek; Filip, Petr; Zatloukal, M.; Tzoganakis, C.

255

Investigation of polypropylene fiber effect to the silica fume concrete  

Directory of Open Access Journals (Sweden)

Full Text Available target, the effect of alkali-silica reaction and sulfate provides many benefits like getting under control. Optimum silica fumes may be added to concrete, high strength and low heat in the hidratasyon destination, alkali silica reaction and to provide permeability under control provides many benefits such as receiving the effect of sulfate. Search surface area silica fumes contribution aggregates-paste without spaces and more than high strength concretes. However, there are also negative effects such as silica exposure by being streamed. The amount of the relative values of these effects optimum silica smoke and cement, aggregates, is determined based on the type and quantities such as the terms of maintenance with plasticizer additive factors are also affected. Polymer fibers, giving the best results and to participating in, and the most widely used polypropylene fiber blends. Polypropylene fiber concrete in three dimensions by creating a micro accessory network, reduce the deficit and the presence of natural concrete to be pumped some properties. In this study, exposure to silica, which is a waste material in theindustrial field on theproperties of concrete betonunda and silica exposure by joining concrete to improve the effects of the adverse effects on properties of polypropylene fiberconcrete.Keywords: Concrete Technology, Industrial Waste, Silica Fume, Polypropylene Fibers.

Betül Sümer

2013-08-01

256

Broad-line NMR study of hot drawn polypropylene fibres  

International Nuclear Information System (INIS)

The influence of polypropylene fiber hot drawing on molecular mobility of polymer chains has been investigated by line broadening NMR method. Measurements have been done in the temperature range (200-420 K) where ?-relaxation processes in non crystalline regions are dominant and deformation are mostly probable

257

Irradiation effects on the weldability and adhesiveness of polypropylene  

International Nuclear Information System (INIS)

This paper describes the irradiation effects on the tensile characteristics of welded polypropylene and on the adhesiveness of this material. Polypropylene plates of 2 mm in thickness were but welded by using a semiautomatic heating plate welder and exposed to various irradiation doses of neutron. Tensile characteristics of these specimens were examined and measurements of melting point, dissolution rate and molecular weight were made. Examination of X-ray diffraction patterns was also made during tensile tests on neutron-irradiated specimens. Furthermore, the adhesive strength, infrared spectra and surface appearance of neutron-irradiated specimens were examined, and the irradiation effect on the adhesiveness of this materials was also discussed. The results obtained were summarized as follows; (1) The irradiation effects for the welded part are similar to those for the base material of polypropylene, that is, tensile strength decreases with excessive irradiation and brittleness becomes greater with an increase of irradiation dose. (2) The irradiation effects on the melting point, dissolution rate, molecular weight and molecular orientation tendency are correlative with those on the tensile characteristics of neutron-irradiated materials. (3) The adhesive strength of polypropylene increases with irradiation of neutron. This increase seems to be caused by polarization due to irradiation. (author)

258

Natural fibers/polypropylene composite: processing and preliminary structural investigations  

Science.gov (United States)

Biodegradation and physico-mechanical properties allow us to predict a wide application of cellulosic/thermoplastic composites and it is an essential motive for investigations on structure-properties relationship. The preliminary investigations on the structure of composites containing isotactic polypropylene with hemp or flax are presented.

Paukszta, Dominik; Garbarczyk, Jozef

1997-02-01

259

Effects of gamma irradiation on the physical properties of laminated packaging materials. 2. polypropylene-polypropylene, polypropylene-polyethylene, and polyester-polyethylene  

International Nuclear Information System (INIS)

This experiment was done to determine the effects of irradiation on the physical properties of three kinds of laminated packaging materials, i.e. polypropylene-polypropylene, polypropylene-polyethylene, polyester-polyethylene. Observations were made on pinhole production, leakage, oil resistance, resistance against insect penetration, colour, odour tensile strength, elongation at break, seal strength and tear resistance. The samples were irradiated with doses of 0, 5 and 10 kGy, then stored at room temperature and examined after 0, 3, 6 and 12 months of storage. The results showed that irradiation doses up to 10 kGy, as well as storage up to 12 months, did not create pinholes, or leakage in pouches prepared from laminated films. The resistance of the films to oil and insect penetration, the colour, and the odour were also unchanged. Both irradiation and storage treatments had a significant effect on physical properties of the laminated films. In general, the changes started to be significant after 6 months' storage either in unirradiated samples or in irradiated ones. It could be concluded that irradiation with doses up to 10 kGy had no meaningful effect on the physical strength of the laminated films, therefore such films could be used as packaging materials for irradiated foods. (author)

260

Loop security and tensile properties of polyblend and traditional suture materials.  

Science.gov (United States)

Tensile and knot properties of new generation (polyblend) and traditional suture materials in orthopedic surgery were investigated in standard laboratory conditions. Study focused on Fiberwire No. 5 and 2, Ethibond No. 5, 2 and 00, Orthocord No. 2, MaxBraid No. 2, Prolene No. 0 and 00, PDS No. 0 and 00, and Vicryl No. 2, 0 and 00. A 27-cm suture loop was fastened with 10 knots for ten samples for each type. Test parameters were tensile load to failure, elongation at failure point and knot slippage, and volume of 10-fold knots. Results were compared using ANOVA test. Failure load of No. 5 Fiberwire (625.0 ± 30.0 N) was significantly higher compared to all other suture types. Tensile strengths of MaxBraid No. 2 (287 ± 11 N) was significantly stronger compared to two other No. 2 polyblend sutures types and Ethibond No. 5. Knot slippage of Fiberwire No. 5 (14 ± 1.9 mm) was significantly higher compared to all other suture types. Ethibond No. 2 (0.1 ± 0.3 mm) had the lowest knot slippage. Elongation at the failure point of Fiberwire No. 2 (5%) was significantly lower than all other suture types. Mean calculated knot volume of #5 Fiberwire (73 ± 6.9 mm(3)) was significantly higher compared to #5 Ethibond (53 ± 4.8 mm(3)). Results of the study proved presence of significant differences between tensile and knot properties of various suture types and sizes. Loop security of larger diameter sutures is not always higher than thinner sutures. Suture elongation and knot slippage are important failure modes for high-diameter sutures and short-suture loops. PMID:20535447

Türker, Mehmet; K?l?ço?lu, Onder; Salduz, Ahmet; Bozda?, Ergun; Sünbülo?lu, Emin

2011-02-01

261

Identification and dynamics of a cryptic suture zone in tropical rainforest  

OpenAIRE

Suture zones, shared regions of secondary contact between long-isolated lineages, are natural laboratories for studying divergence and speciation. For tropical rainforest, the existence of suture zones and their significance for speciation has been controversial. Using comparative phylogeographic evidence, we locate a morphologically cryptic suture zone in the Australian Wet Tropics rainforest. Fourteen out of 18 contacts involve morphologically cryptic phylogeographic lineages, with mtDNA se...

Moritz, C.; Hoskin, C. J.; Mackenzie, J. B.; Phillips, B. L.; Tonione, M.; Silva, N.; Vanderwal, J.; Williams, S. E.; Graham, C. H.

2009-01-01

262

Tissue Reactions to Various Suture Materials Used in Oral Surgical Interventions  

OpenAIRE

A variety of suture materials are available for primary wound closure following oral surgical procedures. The aim was to review the tissue reactions to the various suture materials used in oral surgical interventions. Databases were searched using the following keywords: cotton, nylon, polyglecaprone 25, polytetrafluoroethylene (ePTFE), Polyglactin 910, polyglycolic acid (PGA), polylactic acid, silk, surgery, suture, and tissue reaction. Articles published only in English language were includ...

Romanos, Georgios E.; Khalid Al-Hezaimi; Fawad Javed; Mansour Al-Askar; Khalid Almas

2012-01-01

263

Arthroscopic Posterior Stabilization of the Shoulder Using a Percutaneous Knotless Mattress Suture Technique  

OpenAIRE

Posterior shoulder instability is far less common than anterior instability, and its arthroscopic treatment can be technically demanding. We describe a percutaneous arthroscopic technique for posterior shoulder stabilization using mattress sutures and knotless anchors. Spinal needles are used to pass the sutures percutaneously in a mattress fashion. Knotless anchors are used to secure the sutures under the labrum. These anchors can be used without cannulas, giving easier access to the posteri...

Tennent, Duncan; Concina, Chiara; Pearse, Eyiyemi

2014-01-01

264

Modified Technique of Stapled Esophagojejunostomy Without a Purse-String Suture  

OpenAIRE

Placement of a purse-string suture during a stapled esophagojejunostomy following total gastrectomy is a technically demanding and time consuming procedure. Improper placement of the purse-string suture can lead to anastamotic breakdown with its associated complications. We describe a technique of stapled esophagojejunostomy without using a purse-string suture. We used this technique in 35 patients including 4 patients who underwent an extended total gastrectomy. We encountered a difficulty o...

Seshadri, Ramakrishnan Ayloor; Thammaiah, Siddappa K.; Vaidhyalingam, Venktesh

2011-01-01

265

Comparative study of microepineurial anastomoses with the use of CO2 laser and suture techniques in rat sciatic nerves: Part 1. Surgical technique, nerve action potentials, and morphological studies.  

Science.gov (United States)

The possibility of utilizing the CO2 laser for neural anastomoses was investigated in a rat sciatic nerve model. One nerve in each animal was acutely divided and anastomosed using 10-0 nylon epineurial sutures, while the opposite side was joined by "welding" the opposed nerve ends together with CO2 laser pulses. The surgical incisions were reexplored 60 days postoperatively, action potentials were recorded across the anastomoses, and the nerves were removed for light and electron microscopy. The operative patency rate in the suture group was 100%, compared to 87% in the laser group. Among those animals with bilaterally intact nerves, action potentials could be recorded across the anastomotic site in 78% of the sutured preparations and in 85% of nerves spot-welded with the CO2 laser. Morphological studies showed a greater degree of scar tissue formation and constriction in the anastomotic zone of the nerves joined by sutures than was present in laser-treated animals. We believe these preliminary observations suggest that the CO2 laser may have a role to play in peripheral nerve surgery. Further study of this technique is warranted. PMID:3929156

Fischer, D W; Beggs, J L; Kenshalo, D L; Shetter, A G

1985-08-01

266

Rheometric research of polypropylene Licocene PP2602 melts  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: To comprehend and ascertain reasons of the transition into the non-Newtonian viscosity zone for the melted polypropylene material, depending upon the number of recycling series.Design/methodology/approach: There were carried researches on rheological features of the primary material of the melted polypropylene Licocene PP2602, subjected to be processed repeatedly in as many series as needed, using the Brookfield viscometer CAP2000+ within the temperature range 130-200ºC and the shear rate range 166-3000 s–1.Findings: There were obtained dependence of polypropylene melt viscosity against the shear rate at fixed temperatures, and dependence of polypropylene melt shear stress against the shear rate at fixed temperatures with the non-Newtonian viscosity transient zone shifting into the zone of greater shear rate values as the temperature increases. Also there was obtained dependence of the shear stress critical value on the number of recycling series, where the corresponding critical shear rate value grows as this number increases. This may be applied for predetermining the state of the repeatedly processed polymer material.Research limitations/implications: The found rheometric regularities reflect behaviour for a homologous series of the polymer, but most probably they are generic for all polyolefines, what should be investigated and ascertained subsequently.Practical implications: On the ground of the ascertained temperature-rate dependences of the polypropylene melt flow, there has appeared a possibility to gain a quantitative response about the secondary low-density-polyethylene material state, what allows selecting strategically the way of controlling this material properties, and that let develop new composites of those recycled materials for manufacturing footwear at enterprise “Vzuteks” (Khmelnytskyy.Originality/value: The present paper states that processing the polymer materials repeatedly influences directly on their rheological parameters, increasing, particularly, the melt shear rate critical value.

V.V. Romanuke

2011-07-01

267

Follow up CT findings of suture granuloma in the chest wall: A case report  

International Nuclear Information System (INIS)

Suture granuloma is a benign tumor defined by an inflammatory reaction and the formation of granuloma, which is caused by the reaction of a foreign body in regards to suture material after surgery. Recently, it has been reported as one of the rare complications following surgery, mainly in regards to non absorbable sutures. The authors hereby report a case along with CT findings and literature review for suture granuloma in the chest wall after lung lobectomy for lung cancer in a 65 year old woman

268

Follow up CT findings of suture granuloma in the chest wall: A case report  

Energy Technology Data Exchange (ETDEWEB)

Suture granuloma is a benign tumor defined by an inflammatory reaction and the formation of granuloma, which is caused by the reaction of a foreign body in regards to suture material after surgery. Recently, it has been reported as one of the rare complications following surgery, mainly in regards to non absorbable sutures. The authors hereby report a case along with CT findings and literature review for suture granuloma in the chest wall after lung lobectomy for lung cancer in a 65 year old woman.

Lee, Ka Eun; Lee, Young Kyung [Kyung Hee Univ. Hospital at Gangdong/School of Medicine/Kyung Hee Univ. Seoul, (Korea, Republic of); Sung, Dong Wook [Kyung Hee Univ. Hospital/School of Medicine/Kyung Hee Univ., Seoul, (Korea, Republic of)

2012-09-15

269

Non infective severe aortic paravalvular leakage 7 years after surgery: the role of suture technique.  

Science.gov (United States)

We report a case of redo aortic prosthesis replacement for a severe paravalvular leak (PVL) in a man operated with continuous suture technique 7 years earlier. The severe aortic regurgitation was due to the rupture of the suture. In spite of operations to replace malfunctioning heart valves are common procedures and performed all over the world from more than 50 years, there is still an open debate about the most suitable suture technique. In this case report, we'll discuss if the suture technique has a role in preventing or leading complications as severe PVL. PMID:21513562

Agrifoglio, Marco; Filippini, Sara; Roberto, Maurizio; Zanobini, Marco; Gregorini, Luisa; Alamanni, Francesco

2011-01-01

270

Non infective severe aortic paravalvular leakage 7 years after surgery: the role of suture technique  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract We report a case of redo aortic prosthesis replacement for a severe paravalvular leak (PVL in a man operated with continuous suture technique 7 years earlier. The severe aortic regurgitation was due to the rupture of the suture. In spite of operations to replace malfunctioning heart valves are common procedures and performed all over the world from more than 50 years, there is still an open debate about the most suitable suture technique. In this case report, we'll discuss if the suture technique has a role in preventing or leading complications as severe PVL.

Gregorini Luisa

2011-04-01

271

Investigation of microcirculatory changes in the duodenum of dogs caused by surgical suture materials.  

Science.gov (United States)

Surgical suture materials play an important role in the safe performance of surgical interventions. In our experiments we made an attempt to investigate what microcirculatory changes result from pulling the thread through the wall of the duodenum in Lembert stitches by including 3 kinds of absorbable and non-absorbable suture materials each (Catgut, Dexon, PDS, Silk, Ethibond, Ethilon). Research is still in the pre-experimental stage. In the long run, we hope to enrich the description of these suture materials by some new details. It could help prevent suture insufficiency, facilitate wound healing and thus, improved surgical safety. PMID:9408372

Petö, K; Nagy, A; Hauck, M; Mikó, I; Furka, I

1997-01-01

272

Cystoscopic suture removal by Holmium-YAG laser after Burch procedure  

Directory of Open Access Journals (Sweden)

Full Text Available Burch colposuspension remains one of the successful operations performed for stress incontinence. Accidental suturing of the bladder wall during the procedure or subsequent erosion may lead to lower urinary tract symptoms. Diagnosis and management of these sutures indicate precise evaluation for which a 70 degree cystoscope is used. In selected cases, Holmium-YAG laser may enable us to manage long-standing, encrustated neglected sutures. Here we would like to report successful removal of intravesical sutures using the Holmium-YAG laser.

?skender Ba?er

2011-03-01

273

Extrusion of bone anchor suture following flexor digitorum profundus tendon avulsion injury repair.  

LENUS (Irish Health Repository)

Flexor digitorum profundus (FDP) zone I tendon avulsion injury is traditionally repaired with a pullout suture technique. More recently, bone anchor sutures have been used as a viable alternative and have largely replaced areas in hand surgery where pullout suture technique was once required. To date, there have been very few complications reported related to bone anchor suture use in FDP tendon reattachment to the bone. We report a very unusual case of extrusion of bone anchor through the nailbed, 6 years after zone I FDP tendon avulsion injury repair and a brief review of literature.

Tiong, William H C

2011-09-01

274

A Comparative In Vivo Study of Tissue Reactions to Four Suturing Materials  

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Full Text Available INTRODUCTION: The purpose of this study was to compare the histopathologic reaction of four suturing materials: silk, polyvinylidene fluoride (PVDF, polyglycolic acid, and catgut in the oral mucosa of albino rabbits. MATERIALS AND METHODS: The twenty-one male mature albino rabbits which were used in this study were randomly divided into three groups of seven each. Silk, PVDF, polyglycolic acid and catgut suture materials were tested in the oral mucosa of these animals. The animals were sacrificed 2, 4, and 7 days after suturing. Two pathologists evaluated the samples by determining the presence and level of inflammation, granulation tissue, and fibrosis formation. Data were statistically analyzed by Kruskal Wallis and Mann-Whitney U tests. RESULTS: Histological features of the samples showed that PVDF and plain catgut suture materials produced more fibrous tissue (favorable response on the fourth day in comparison with silk suture (P=0.02. Also, in the 7-day samples PVDF sutures produced the mildest inflammation when compared with the silk sutures (P=0.015. CONCLUSION: According to the results of this study, it can be convey that PVDF suture materials created mild tissue reactions and can be a reasonable candidate for suturing oral tissues.

Shahla Kakoei

2010-06-01

275

Evaluation of surgical implantation of electronic tags in European eel and effects of different suture materials  

DEFF Research Database (Denmark)

Effects of implanting data-storage tags in European eel, Anguilla anguilla, and the suitability of different suture materials (braided permanent silk, permanent monofilament, absorbable and absorbable antibacterial) were examined. The tags consisted of an electronic unit and three floats on a wire, making them flexible and able to follow the swimming movements of the eel. No mortality occurred, and tagged fish did not differ from the control fish in growth. Sutures were shed or dissolved slowly. After 4 weeks, there was no difference among the groups in the proportion of sutures left. After 6 months, fish with braided silk had largely shed their sutures, fish with monofilament sutures had the majority of sutures left, whereas the fish with absorbable sutures were intermediate in between. Fish with monofilament sutures showed the least-extensive inflammation reactions and fastest wound healing. Antibacterial treatment had no effect on inflammation or healing rates. After 6 months, the tag started to become expelled through the incision in five fish (12%). The internal reaction appeared stronger around the floats, suggesting that the coating material of the floats created a tissue reaction, which should be further investigated. Intraperitoneal implantation appears to be a suitable tagging method for European silver eel, and it is recommended to close incisions using permanent monofilament sutures

Thorstad, Eva B.; Økland, Finn

2013-01-01

276

Development of foams from linear polypropylene (PP) and high melt strength polypropylene (HMSPP) polymeric blends  

International Nuclear Information System (INIS)

Foamed polymers are future materials, with a comprehensive application field. They can be used in order to improve appearance of insulation structures, for example, or to reduce costs involving materials. This work address to Isotactic Polypropylene / High Melt Strength Polypropylene blends, for foams production. Rheological behavior of polymer melt, especially referring to viscosity in processing temperature, plays a decisive role in applications where dominates extensional flow, as in case of foaming. If the viscosity is very low, it will correspond to a low melt strength, as in case of linear homopolymer (Isotact PP), and the foam will be prejudiced, due to the impossibility of expansion. Otherwise, if the viscosity is very high, with a high melt strength, the foam will collapse immediately after its formation. In order to get foams with an homogeneous and defined cellular structure, there were accomplished blends, 50% in weight, between linear homopolymer (isotactic PP) and HMSPP, from PP modified as per gamma radiation, in acetylene environment and at a 12.5 kGy doses. Extrusion process used a soluble foaming methodology, according to a processing/dissolution principle, which involves the dissolution of a Physical Blowing Agent (PBA), under 30 bar pressure, homogeneously mixed with polymeric melt. Extrusion conditions, that generally involve temperature, pressure and viscoelastic material flow control were experimentally investigated to define prevalent characteristics for producing foams. Nitrogen was the used PBA and process extrusion parameters were adapted to PP, HMSPP and their 50% in weight mixtures thereof. Major PP and HMSPP characteristics were obtained via melt Index and melt strength and thermal analyses (DSC/TGA), in order to make viable and to reproduce foaming as per extrusion process. Foams cellular morphology of PP, HMSPP and their 50% in weight mixtures thereof was investigated, with and without talc addition, as nucleating agent, by using Scanning Electron Microscope (SEM). Micrographs obtained pointed to closed cells foams, in which the pressure is kept during all cell formation stage, informing that closed cells foams are used in thermal insulation in Civil Construction and in thermal vials. Density analyses accomplished in foams produced in our work showed typical results for high density foams (320 to 800 kg/m3 range), around 500 kg/m3, used for wire and cables and for structural purposes (structural foams), by replacing wood, metals or solid plastics. Structural foams have high density (above 320 kg/m3) and cellular structures are specially composed by holes. (author)

277

Evaluation of polypropylene/saw dust composites prepared with maleated polypropylene (mapp) produced by reactive extrusion  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Considering the importance of the environment and fuel economy, the Brazilian automotive industry has focused on the development of lightweight materials based on renewable resources. Replacement of PP- talc composite by PP- saw dust composite is a promising possibility. This paper presents the prep [...] aration of maleated polypropylene (MAPP) through reactive extrusion using different amounts of peroxides and maleic anhydride as well its characterization. Using 20% of saw dust coated with different amounts of prepared MAPP, several composites were prepared including one with commercial MAPP. Injection molded samples of all these composites along with that without the compatibilizer were characterized for mechanical properties. These studies indicated fulfilling the proposed objectives: (i) finding the optimal reactive extrusion conditions to prepare MAPP samples; (ii) preparation of PP/saw dust composites with and without MAPP coating; (iii) to arrive at optimized composite to get the best performance through their characterization for various properties of all the produced composites.

Ernani, Trombetta; Thais, Flores-Sahagun; Kestur G., Satyanarayana.

278

Cranial sutures and craniometric points detected on MRI.  

Science.gov (United States)

The main goal of the study was to determine on MRI the cranial sutures, the craniometric points and craniometric measurements, and to correlate these results with classical anthropometric measurements. For this purpose, we reviewed 150 cerebral MRI examinations considered as normal (Caucasian population aged 20-49 years). For each examination we individualized 11 craniometric landmarks (Glabella, Bregma, Lambda, Opisthocranion, Opisthion, Basion, Inion, Porion, Infra-orbital, Eurion) and three measurements. Measurements were also calculated independently on 498 dry crania (Microscribe 3-DX digitizer). To validate the MRI procedure, we measured four dry crania by MRI and with compass or digital caliper gauges. Cranial sutures always appeared without signal (black), whatever the MRI sequence used, and they are better visualized with a 5 mm slice thickness (compact bone overlapping). Slice dynamic analysis and multiplanar reformatting allowed the detection of all craniometric points, some of these being more difficult to detect than others (Porion, Infra-orbital). The measurements determined by these points were as follows: Vertex-Basion height=135.66+/-6.56 mm; Eurion-Eurion width=141.17+/-5.19 mm; Glabella-Opisthocranion length=181.94+/-6.40 mm. On the midline T1-weighted sagittal image, all median craniometric landmarks can be individualized and the Glabella-Opisthocranion length, Vertex-Basion height and parenchyma indices can be calculated. Craniometric points and measurements between these points can be estimated with a standard cerebral MRI examination, with results that are similar to anthropometric data. PMID:15517262

Cotton, François; Rozzi, Fernando Ramirez; Vallee, Bernard; Pachai, Chahin; Hermier, Marc; Guihard-Costa, Anne-Marie; Froment, Jean-Claude

2005-03-01

279

Modification of the internal suture technique for mallet finger.  

Science.gov (United States)

This article describes a treatment of tendinous mallet finger deformities using a modified internal suture technique for the stable fixation of the terminal extensor tendon and bone.Between March 2011 and July 2013, 15 patients with mallet fingers who had been treated using this modification were included in this study. The patients included 10 men and 5 women with a mean age of 33 years (range, 19-50 years). Of these patients, 9 had chronic mallet fingers, 3 were unable to comply with a splinting regimen, and 3 had a history of unsuccessful splinting therapy. The mean time between the injury and surgery was 5.5 months (range, 1-15 months). We graded the results using Crawford criteria.The mean follow-up period was 12 months (range, 9-16 months). The mean final active range of motion of the distal interphalangeal joint flexion was 73° (range, 60°-90°). Based on Crawford evaluation criteria, 8 patients were graded as excellent, 6 were graded as good, and 1 was graded as fair. Apart from 2 documented mild nail deformities, no complications were encountered.This modified technique should be considered for the management of a tendinous mallet finger deformity when the internal suture technique is planned. PMID:25674757

Jiang, Bo; Wang, Peiji; Zhang, Yong; Zhao, Jiaju; Dong, Qirong

2015-02-01

280

An experimental model to retraining in microvascular suture  

Scientific Electronic Library Online (English)

Full Text Available PURPOSE: To demonstrate an experimental model of up to four hours a week of independent study that allows relearning in microvascular sutures. METHODS: Wistar rats between 200 and 500 grams surplus research experiments were used. Femoral vessels are covered on one or both sides through a groin i [...] ncision obliquely along the inguinal ligament. Femoral artery and vein are isolated and measured being clamped and cut. The individual performs in microvascular anastomosis complexity arterial and venous terminoterminal sequence. terminolateral and venous and arterial grafts in vessels. Permeability is evaluated by testing vascular patency after creation of microvascular anastomosis. RESULTS: In the first specimen, only arterial and venous vascular anastomosis are performed terminoterminal. The average diameter of the femoral veins varies from 0.8 to 2 mm between rodents (artery, between 0.6 and 1.4 mm, between 0.8 and 2 mm vein). The superficiality of the vessels allows faster dissection, may also be held in other inguinal region. CONCLUSION: The model of individual retraining allows learning microvascular suture in individuals of permanent staff.

Marcos Ricardo de Oliveira, Jaeger; Pedro Bins, Ely; Jefferson André, Pires; Lydia Masako, Ferreira.

281

Revisiting the Variscan transpressional tectonics in the Southwestern Iberian suture  

Science.gov (United States)

The boundary between the Ossa-Morena Zone (OMZ) and the South Portuguese Zone (SPZ) in southwest Iberia is a Variscan collisional suture with transpressive left-lateral kinematics, contrasting with the dextral component that characterizes most of the Variscan convergence in other regions of the Orogen. Recent work including new structural and radiometric data has improved our knowledge on the geometry and timing of deformations affecting the OMZ/SPZ suture, which can be summarized as follows: Closure of the Rheic Ocean in Late Devonian time is attested by high-pressure and ophiolitic thin allochthonous units emplaced on the southern border of the OMZ. The kinematic interpretation of early stretching lineations and tectonic fabrics indicate that these units were emplaced in a tectonic regime of oblique left-lateral convergence. Transient transtension in Early Carboniferous time gave way to a narrow aisle of newly-formed oceanic-like crust just over the foregoing Rheic Ocean suture, accompanied by mafic magmatism intruded/extruded at both continental sides. Radiometric dating has yielded the same age of around 340 Ma for the oceanic-like mafic protholiths and their granulite/amphibolite facies tectonic fabric, thus indicating the very ephemeral life of the oceanic-like strip. Oblique convergence was resumed immediately after transtension, first causing northward obduction of the oceanic-like unit and north-verging folding in metasedimentary units of the southern border of the suture. Later on, a south-vergent regional fold was developed synchronous with left-lateral granulite-amphibolite facies shearing. Finally, shear deformation gave way to a low pitch stretching lineation, thrusting the OMZ over SPZ, concentrated on the southern limb of this regional fold and constituting a complex ductile 2-3 km-thick shear band evolving from amphibolite to greenschist facies, developing: (i) high-temperature greenschists at the southern border of the mafic oceanic-like unit, which propagated southwards progressively cooling to low-temperature greenschists; (ii) disruption of layers that produced small fishes of weakly deformed rocks, previously interpreted as sedimentary mélanges. Radiometric dating of acid volcanic rocks included in the low-grade shear zone has yielded an age of 337 Ma, putting an older limit to shearing. At late Variscan time, a brittle left-lateral shear band partially obliterated the previous syn-metamorphic shear zone. Oblique convergence propagated southwards across the SPZ in Late Carboniferous time, though lateral displacements decreased rapidly in favor of shortening. This deformation has been roughly modelled as a transpressional band characterized by 40% shortening and ?=1 shearing. An age of 330 Ma yielded by a deformed granite at the northern part of the SPZ probably indicates the arrival of deformation at that point, while stratigraphic data suggest that deformation reached SW Portugal at around 310 Ma. To conclude, the transpressive OMZ/SPZ boundary shows strain partitioning, with left-lateral displacements concentrated in ductile to brittle shear zones affecting the suture units, and moderately oblique shortening affecting a broad zone of the SPZ foreland.

Pérez Cáceres, Irene; Martínez Poyatos, David; Simancas, José Fernando; Azor, Antonio

2014-05-01

282

Effect of gamma irradiation on the enzymatic degradation of polyglycolic acid absorbable sutures  

International Nuclear Information System (INIS)

The effect of gamma irradiation on the enzymatic as well as the in vivo degradation of polyglycolic acid sutures was examined. The sutures of size 2-0 were irradiated at dosage levels of 0-20 mrad. The three enzymes chosen for this study were esterase, alpha-chymotrypsin, and trypsin. The irradiated sutures were both immersed in the enzyme solutions; their corresponding buffer controls, and implanted in inbred black-and-white hooded hister rats (Liverpool strain). The degradation of PGA sutures was determined mechanically. Among the three enzymes studied, esterase showed the highest enzymatic effect on the degradation of the unirradiated and irradiated PGA sutures. Trypsin's effect on PGA sutures was not observed until 20 mrad. The findings of trypsin demonstrated the hypothesis that synthetic high molecular weight polymers, which are initially resistant to enzymatic degradation, could become prone to enzymatic attack after altering their physical and chemical structures. Implanted PGA sutures maintained a similar or slightly higher mean tensile breaking strength in in vivo degradation compared to in vitro degradation (0.1M tris buffer of pH . 7.5); these degradation profiles suggest that PGA does not display similar behavior in in vivo and in vitro degradations. The magnitude of dissimilarity depends on the radiation dosage and on the duration of degradation, and is speculated to be attributable to the specific action of enzymes with respect to the configuration and mes with respect to the configuration and chemical structure of the PGA sutures

283

Effect of gamma irradiation on the enzymatic degradation of polyglycolic acid absorbable sutures  

Energy Technology Data Exchange (ETDEWEB)

The effect of gamma irradiation on the enzymatic as well as the in vivo degradation of polyglycolic acid sutures was examined. The sutures of size 2-0 were irradiated at dosage levels of 0-20 mrad. The three enzymes chosen for this study were esterase, alpha-chymotrypsin, and trypsin. The irradiated sutures were both immersed in the enzyme solutions; their corresponding buffer controls, and implanted in inbred black-and-white hooded hister rats (Liverpool strain). The degradation of PGA sutures was determined mechanically. Among the three enzymes studied, esterase showed the highest enzymatic effect on the degradation of the unirradiated and irradiated PGA sutures. Trypsin's effect on PGA sutures was not observed until 20 mrad. The findings of trypsin demonstrated the hypothesis that synthetic high molecular weight polymers, which are initially resistant to enzymatic degradation, could become prone to enzymatic attack after altering their physical and chemical structures. Implanted PGA sutures maintained a similar or slightly higher mean tensile breaking strength in in vivo degradation compared to in vitro degradation (0.1M tris buffer of pH . 7.5); these degradation profiles suggest that PGA does not display similar behavior in in vivo and in vitro degradations. The magnitude of dissimilarity depends on the radiation dosage and on the duration of degradation, and is speculated to be attributable to the specific action of enzymes with respect to the configuration and chemical structure of the PGA sutures.

Chu, C.C.; Williams, D.F.

1983-11-01

284

A novel technique of rotator cuff repair using spinal needle and suture loop  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background We present a simple technique of arthroscopic rotator cuff repair using a spinal needle and suture loop. Methods With the arthroscope laterally, a spinal needle looped with PDS is inserted percutaneously into the shoulder posteriorly and penetrated through the healthy posterior cuff tear margin. Anteriorly, another spinal needle loaded with PDS is inserted percutaneously to engage the healthy tissue at the anterior tear margin. The suture in the anterior needle is then delivered into the suture loop of the posterior needle using a suture retriever. The posterior needle and loop are then pulled out carrying the anterior suture with it. The two limbs of this suture are then retrieved through a cannula for knotting. The same procedure is then repeated for additional suturing. Suture anchors placed over the greater tuberosity are used to complete the repair. Conclusion This is an easy method of rotator cuff repair using simple instruments and lesser time, hence can be employed at centers with less equipment and at reduced cost to the patient.

Muzaffar Nasir

2010-11-01

285

Skin closure using staples and nylon sutures: a comparison of results.  

OpenAIRE

A disposable skin stapler (Elite: Auto Suture UK Ltd) and Nylon vertical mattress sutures have been used for skin closure. The complications related to each method were evaluated in 129 wounds. There was a higher incidence of inflammation, discomfort on removal and spreading of the healing scar associated with staples. The only advantage of staples was speed of wound closure.

Stockley, I.; Elson, R. A.

1987-01-01

286

Thermal Characterizations of Silver-containing Bioactive Glass-coated Sutures  

OpenAIRE

Abstract This study utilized and compared a number of thermal analysis methods to characterize the thermal properties of commercial sutures with and without antimicrobial coatings of silver-doped bioactive glass (AgBG) interlocking particulates. The effect of a slurry dipping technique used to coat resorbable Vicryl® (polyglactin 910) and non-resorbable Mersilk® surgical sutures with AgBG was investigated...

Blaker, Jonny J.; Boccaccini, Aldo R.; Nazhat, Showan N.

2005-01-01

287

Arthroscopic repair of peripheral triangular fibrocartilage complex tears with suture welding: a technical report.  

Science.gov (United States)

This report presents a method of arthroscopic repair of the peripheral triangular fibrocartilage complex tears that replaces traditional suture knots with ultrasonic welding of sutures. This will help eliminate potential causes of ulnar-sided wrist discomfort during the postoperative period. PMID:17027791

Badia, Alejandro; Jiménez, Alexis

2006-10-01

288

Evaluation of five different suture materials in the skin of the earthworm (Lumbricus terrestris).  

Science.gov (United States)

The purpose of this study was to determine which suture material is the most appropriate for dermal closure of terrestrial annelids. This paper describes the tissue reactions of the earthworm, Lumbricus terrestris, to five different types of suture materials in order to determine which suture material is the most appropriate for dermal closure. Silk, monofilament nylon, polydiaxonone, polyglactin 910, and chromic gut were studied. There was mild to moderate tissue reaction to all five suture materials. In all of the biopsies wound-healing reaction consisted of aggregates of blastemal cells which appeared in various stages of dedifferentiation from the body wall. Inflammatory cells infiltrated the wound sites, reminiscent of the typical foreign body reaction in vertebrates. The results indicate polyglactin 910 would be the best suture material with regards to tissue security and reaction scores. Chromic gut occupies the next position but there were problems with suture security over time. This appears to be the first suture material performance study on a terrestrial invertebrate. The earthworm, Lumbricus terrestris, was chosen for its wide availability, size, and the extensive species knowledge base. The earthworm may prove to be a good surgical/suture model for economically important invertebrates such as mollusks, tunicates, and insect larval stages. PMID:25143875

Salgado, Melissa A; Lewbart, Gregory A; Christian, Larry S; Griffith, Emily H; Law, Jerry McHugh

2014-01-01

289

STUDY OF SKIN STAPLES AND CONVENTIONAL SUTURE FOR ABDOMINAL SKIN WOUND CLOSURE  

Directory of Open Access Journals (Sweden)

Full Text Available

Introduction: The use of automatic stapling device for skin closure has become more popular due to its minimum disadvantages as compared to conventional suturing. Hence, this study was undertaken to compare the time required for abdominal skin closure and pain during suture removal, between skin staplers and conventional suture.

Materials and Methods: The study includes 100 patients with age group of 45yrs-75yrs  undergoing elective surgery, of which 50 patients  underwent wound closure by staplers (Group-I and 50 patients underwent closure using  prolene suturing (Group-II, during June 2009 to June 2011 at Basaweshwar Teaching and General Hospital, Gulbarga. Patients were randomly selected for conventional suture and skin staple. Time duration for wound closure was recorded and pain scoring was given during suture removal, between both groups.

Results and conclusion: In our study duration of wound closure was statistically significant (P<0.001 with staplers requiring lesser time than conventional prolene sutures, we also found that pain during suture removal between both groups was statistically significant (P<0.001. We believe the advantages of speed and convenience of skin staples outweigh the extra cost, provided the disposable instruments are reused until empty.

Avinash K. Bhavikatti

2012-08-01

290

Radiation effects in ricinyl-2-oxazoline maleate-modified polypropylene  

International Nuclear Information System (INIS)

Polypropylene (PP) and ricinyl-2-oxazoline maleate-modified polypropylene were irradiated with a 10-MeV electron beam (from a LAE 13/9 linear accelerator). The resulting radicals were studied by electron paramagnetic resonance spectroscopy (EPR). The chemical modification of PP was found to have affected the mechanism of radical formation. The chemical and radiative modification of PP was found to proceeded through the formation of proxy rather than alkyl radicals. The incorporation of ricinyl-2 oxazoline maleate into PP chain- and the degradation of the PP chain by the fast electron beam resulted in a modified melt flow rate index (MFR), viscosity and thermal properties as evidenced by DSC. (author)

291

Mechanical properties of pineapple leaf fibre reinforced polypropylene composites  

International Nuclear Information System (INIS)

Pineapple leaf fibre, which is rich in cellulose, relative inexpensive and abundantly available has the potential for polymer-reinforced composite. The present study investigates the tensile and flexural behaviours of pineapple leaf fibre-polypropylene composites as a function of volume fraction. The tensile modulus and tensile strength of the composites were found to be increasing with fibre content in accordance with the rule of mixtures. The tensile modulus and tensile strength with a volume fraction 10.8% are 687.02 and 37.28 MPa, respectively. The flexural modulus gives higher value at 2.7% volume fraction. The flexural strength of the composites containing 5.4% volume fraction was found to be higher than that of pure polypropylene resin by 5.1%. Scanning electron microscopic studies were carried out to understand the fibre-matrix adhesion and fibre breakage

292

Effects of environmental ageing on HMS-polypropylene/Cloisite nanocomposites  

International Nuclear Information System (INIS)

High melt strength polypropylene Nanocomposites (NC-HMSPP) were obtained with concentrations of 0.1 and 5 wt% of Cloisite 20A. The melt intercalation, using twin screw extruder was done to homogenize the nanocomposite in presence of polypropylene graft maleic anhydride (PP-g-MA) compatibilizer agent. In this work, the manufactured dumbbell samples were settled in device for natural ageing assay. The period of exposition was January to December of 2012. The effects of environmental ageing was determined by carbonyl index (FT-IR) and the results showed that nanocomposites were more stable than HMSPP. The mechanical properties (elongation and rupture strength) were evaluated and the thermal behavior was investigated by differential scanning calorimetry (DSC) and X ray diffraction (DRX). The morphology was observed by scanning electron microscopy (SEM) in which the nanocomposites showed intense cracks on the surface

293

Rheological and Thermal Behavior of Polypropylene-Kaolin Composites  

International Nuclear Information System (INIS)

Kaolins effect on rheological behaviour of polypropylene-kaolin composites was investigated. The research found that not only the kaolin content influence the rheological behaviour but also the compounding using internal mixer and twin screw extruder. In details, viscosity and shear stress increased with addition of kaolin content. These characteristics also exhibited higher in polypropylene-kaolin composite suspensions compounded using twin screw extruder than using internal mixer. Chain scission was assumed to occur and affect the melt properties. Further justification characterized by Differential Scanning Calorimeter (DSC) showed that the effect of kaolin and loading content were more evident on the onset melting temperature and crystallinity. Besides, due to the different cooling operation in both processes, the effect of compounding on melting characteristic was conspicuous. (author)

294

Ziegler-Natta catalyst for polypropylene and polyethylene nanocomposites preparation  

International Nuclear Information System (INIS)

Polypropylene and polyethylene nanocomposites are well known for their improved properties when compared with the neat polymers. In this work we report the preparation, characterization and the activity studies of a fourth generation Ziegler-Natta catalyst for the preparation of polyolefin/clay nanocomposites. The catalyst was prepared treating an organo-modified silicate with magnesium and titanium compounds. The content of titanium and that of the magnesium of the catalyst were determined by UV-vis spectroscopy and atomic absorption respectively. The first results show that the catalyst is active for propylene polymerization being suitable for polypropylene/clay nanocomposite preparation. The catalyst activity for ethylene polymerization was also investigated. The X-ray diffraction patterns of the polyethylene samples suggest the clay exfoliation occurs in the in situ polymerization, even with high clay loading (about 9 %) indicating that a nanocomposite was formed. (author)

295

DSC Study on Polypropylene Modified with Calcium Carbonate Nanoparticles  

International Nuclear Information System (INIS)

The exposure of polypropylene containing various concentrations of calcium carbonate nanoparticles was performed in air and water. The radiolysis products of water determine different behaviour of polymer substrate. The irradiation effect induced on polymer and the contribution of nanoparticles to the scavenging of oxygenated products that were created during ? exposure were investigated by DSC measurements over the temperature range from 340-400 K, the usual temperatures for thermal overcharge. Two kinds of carbonate particles, one type is represented by unmodified filler, while the second type is the superficially modified with stearic acid. The covering of particle surface with stearic acid confers to them a different ability in the abstraction of degradation products formed in irradiated isotactic polypropylene

296

Reinforced polypropylene composites: effects of chemical compositions and particle size.  

Science.gov (United States)

In this work, the effects of wood species, particle sizes and hot-water treatment on some physical and mechanical properties of wood-plastic composites were studied. Composites of thermoplastic reinforced with oak (Quercus castaneifolia) and pine (Pinus eldarica) wood were prepared. Polypropylene (PP) and maleic anhydride grafted polypropylene (MAPP) were used as the polymer matrix and coupling agent, respectively. The results showed that pine fiber had significant effect on the mechanical properties considered in this study. This effect is explained by the higher fiber length and aspect ratio of pine compared to the oak fiber. The hot-water treated (extractive-free) samples, in both wood species, improved the tensile, flexural and impact properties, but increased the water absorption for 24h. This work clearly showed that lignocellulosic materials in both forms of fiber and flour could be effectively used as reinforcing elements in PP matrix. Furthermore, extractives have marked effects on the mechanical and physical properties. PMID:19948401

Ashori, Alireza; Nourbakhsh, Amir

2010-04-01

297

POLYPROPYLENE/STARCH BLENDS: STUDY OF THERMAL AND MORPHOLOGICAL PROPERTIES  

Scientific Electronic Library Online (English)

Full Text Available Polypropylene/starch blends were prepared using starch of different botanical source. The influence of starch type and starch content on thermal properties and morphology of polypropylene/starch blends was studied. Corn and potato starches were used as starch source. The starch content in the blends [...] was 7 and 15 wt-%. Characterization of PP and PP/starch blends by (DSC), (TGA), and (SEM) was carried out to obtain information on miscibility among PP and starch. The starch domains exhibited characteristic voids be due to thermal degradation. Two types of PP, PP1 poly(propylene-co-ethylene), random copolymer, and PP3 poly(propylene-co-ethylene), heterophasic copolymer were studied.

MONICA A, PÉREZ R; BERNABÉ L, RIVAS Q; SADDYS, RODRÍGUEZ-LLAMAZARES.

1643-16-01

298

Effects of environmental ageing on HMS-polypropylene/Cloisite nanocomposites  

Energy Technology Data Exchange (ETDEWEB)

High melt strength polypropylene Nanocomposites (NC-HMSPP) were obtained with concentrations of 0.1 and 5 wt% of Cloisite 20A. The melt intercalation, using twin screw extruder was done to homogenize the nanocomposite in presence of polypropylene graft maleic anhydride (PP-g-MA) compatibilizer agent. In this work, the manufactured dumbbell samples were settled in device for natural ageing assay. The period of exposition was January to December of 2012. The effects of environmental ageing was determined by carbonyl index (FT-IR) and the results showed that nanocomposites were more stable than HMSPP. The mechanical properties (elongation and rupture strength) were evaluated and the thermal behavior was investigated by differential scanning calorimetry (DSC) and X ray diffraction (DRX). The morphology was observed by scanning electron microscopy (SEM) in which the nanocomposites showed intense cracks on the surface.

Komatsu, L. G. H., E-mail: dfparra@ipen.br; Oliani, W. L., E-mail: dfparra@ipen.br; Ferreto, H. F. R., E-mail: dfparra@ipen.br; Lugao, A. B., E-mail: dfparra@ipen.br; Parra, D. F., E-mail: dfparra@ipen.br [Nuclear and Energy Research Institute, IPEN-CNEN/SP (Brazil)

2014-05-15

299

Functionalization of silica nanoparticles for polypropylene nanocomposites applications  

International Nuclear Information System (INIS)

Synthetic silica nanospheres of different diameters produced via the sol-gel method were used in order to enhance the barrier properties of the polypropylene-silica nanocomposites. Modification of the silica surface by reaction with organic chlorosilanes was performed in order to improve the particles interaction with the polypropylene matrix and its dispersion. Unmodified and modified silica nanoparticles were characterized using electronic microscopy (TEM), elemental analysis, thermo gravimetric analysis (TGA), and solid state nuclear magnetic resonance (NMR) spectroscopy. Preliminary permeability tests of the polymer-silica nanocomposite films showed no significant change at low particles load (3 wt%) regardless its size or surface functionality, mainly because of the low aspect ratio of the silica nanospheres. However, it is expected that at a higher concentration of silica particles differences will be observed. (author)

300

The Roman Bridge: a "double pulley – suture bridges" technique for rotator cuff repair  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background With advances in arthroscopic surgery, many techniques have been developed to increase the tendon-bone contact area, reconstituting a more anatomic configuration of the rotator cuff footprint and providing a better environment for tendon healing. Methods We present an arthroscopic rotator cuff repair technique which uses suture bridges to optimize rotator cuff tendon-footprint contact area and mean pressure. Results Two medial row 5.5-mm Bio-Corkscrew suture anchors (Arthrex, Naples, FL, which are double-loaded with No. 2 FiberWire sutures (Arthrex, Naples, FL, are placed in the medial aspect of the footprint. Two suture limbs from a single suture are both passed through a single point in the rotator cuff. This is performed for both anchors. The medial row sutures are tied using the double pulley technique. A suture limb is retrieved from each of the medial anchors through the lateral portal, and manually tied as a six-throw surgeon's knot over a metal rod. The two free suture limbs are pulled to transport the knot over the top of the tendon bridge. Then the two free suture limbs that were used to pull the knot down are tied. The end of the sutures are cut. The same double pulley technique is repeated for the other two suture limbs from the two medial anchors, but the two free suture limbs are used to produce suture bridges over the tendon, by means of a Pushlock (Arthrex, Naples, FL, placed 1 cm distal to the lateral edge of the footprint. Conclusion This technique maximizes the advantages of two techniques. On the one hand, the double pulley technique provides an extremely secure fixation in the medial aspect of the footprint. On the other hand, the suture bridges allow to improve pressurized contact area and mean footprint pressure. In this way, the bony footprint in not compromised by the distal-lateral fixation, and it is thus possible to share the load between fixation points. This maximizes the strength of the repair and provides a barrier preventing penetration of synovial fluid into the healing area of tendon and bone.

Maffulli Nicola

2007-12-01

301

Anatomical relationship between the parietomastoid suture and transverse sinus. Evaluation by 3D computed tomographic angiography  

International Nuclear Information System (INIS)

The primary aim of this study was to determine whether the parietomastoid suture can be a useful landmark to localize the transverse sinus. Three-D computed tomographic angiograms in 37 cases were evaluated using the following two assessments. One defined the relationship between the extended line of the parietomastoid suture and the transverse sinus (TS). The second determined the anatomic position of the asterion relative to the transverse sigmoid junction (TSJ). In all cases, the extended line of parietomastoid suture ran parallel to the TS. In contrast, the asterion was located above the TSJ in 26 cases (70.3%), at the mid-portion in 4 cases (10.8%), and below in 7 cases (18.9%). The extended line of the parietomastoid suture appears to be a reliable indicator of the location of the TS. The parietomastoid suture can be a useful intraoperative landmark for the TS. (author)

302

Glenoid damage from articular protrusion of metal suture anchor after arthroscopic rotator cuff repair.  

Science.gov (United States)

Arthroscopic repair of rotator cuff tears has been shown to be effective and safe. The use of suture anchors has increased the ability to perform rotator cuff repairs arthroscopically. However, the use of suture anchors for any surgery around the shoulder can result in complications if the devices are not used and inserted properly. Complications that have been reported with the use of suture anchors for rotator cuff surgery include prominent anchors in the tuberosities, dislodged anchors secondary to pull-out or improper insertion, and osteolysis around the anchors. We report a case of articular cartilage damage secondary to a suture anchor protruding through the humeral head because of improper anchor insertion. Our patient's case reminds surgeons not only to be careful of the depth of insertion of suture anchors when performing rotator cuff surgery but also to obtain radiographs to evaluate the anchor position if patients continue to have symptoms after rotator cuff repair using these devices. PMID:25750956

Kim, Yang-Soo; Ok, Ji-Hoon; Garzon-Muvdi, Juan; McFarland, Edward G

2015-03-01

303

Why do we fail in aging the skull from the sagittal suture?  

Science.gov (United States)

The controversy over the reliability of ectocranial suture status (open vs. closed) as an age estimation stimulated the pursuit of Meindl and Lovejoy's suggestion (Meindl and Lovejoy [1985] Am. J. Phys. Anthropol. 68:57-66) for large scale analysis. The extent of the sagittal suture closure was assessed in 3,636 skulls from the Hamann-Todd and Terry collections. The debate over whether cranial suture ossification represents a pathologic or an age-predictable pathologic process also stimulated a comparison with age and two stress markers, hyperostosis frontalis interna and tuberculosis. Sagittal suture closure was found to be age-independent and sexually biased. The wide confidence intervals (for age) appear to preclude meaningful application of suture status for age determination. No correlation was found with the tested biological stressors. PMID:9261501

Hershkovitz, I; Latimer, B; Dutour, O; Jellema, L M; Wish-Baratz, S; Rothschild, C; Rothschild, B M

1997-07-01

304

Physical and Mechanical Properties of Natural Fibers Filled Polypropylene Composites and Its Recycle  

OpenAIRE

This study discusses the influence of natural fiber type on the performance of polypropylene and its recycle. Composites consisting of polypropylene (PP) and natural fiber from wood (Acacia mangium), water hyacinth (Eichornia crassipes), kenaf (Hibiscus cannabinus), banana (Musa paradisiaca) and empty fruit bunch of oil palm (Elaeis guineensis) were prepared by extrusion and compression process based on the ratio of 50:50% (w/w) with the addition of 2.5% polypropylene modified with maleic anh...

Myrtha Karina; Holia Onggo; Anung Syampurwadi

2007-01-01

305

Effect of volume fraction of Polypropylene Fiber on Mechanical Properties of Concrete  

OpenAIRE

In this study, the result of polypropylene fiber on mechanical properties of concrete is studied. Polypropylene fibers of 12mm cut length and 6 denier were added at volume fraction of 0%, 0.25%, 0.50%, 0.75% & 1 %.The cube, cylinder and beams wear tested under two point loads on UTM. The results showed that the addition of polypropylene fiber significantly improved the compressive strength, split tensile strength, flexural strength, reserve strength and ductility of fiber rein...

R. S. Rajguru,; Ghode, A. R.

2014-01-01

306

GC-MS OF POLYETHYLENE AND POLYPROPYLENE THERMAL CRACKING PRODUCTS  

OpenAIRE

Low-density polyethylene and polypropylene were thermally decomposed individually in a batch reactor at 450°C as a recycling route from the aspect of the production of petrochemical feedstock. The resulting transformation liquid products were analysed by high resolution gas chromatographic-mass spectrometric analysis. More detailed separation of polyalkenes splitting compounds was achieved using high resolution GC (efficiencies up to 490 000 plates) than before. The GC-MS as well as the depe...

Martin Bajus; Elena Hájeková; Helena Jurdáková; Robert Kubinec; Ladislav Soják

2006-01-01

307

Property Relationship in Organosilanes and Nanotubes Filled Polypropylene Hybrid Composites  

OpenAIRE

Polypropylene composites with different filler contents were prepared by creating a masterbatch containing 3 wt%. filler. A variety of silanol groups were used to synthetized three compounds in different media trough a sol-gel process with acetic acid, formic acid and ammonium hydroxide as catalysts. Besides, four different nanotubular fillers were also used to analyze their behavior and compare it with the effect caused by the silanol groups. These tubular structures comprise: unmodified hal...

Monsiva?is-barro?n, Alejandra J.; Jaime Bonilla-Rios; Antonio Sánchez-Fernández

2014-01-01

308

Aqueous Processes for Dyeing Generic, Unmodified Polypropylene Fiber  

OpenAIRE

Acid leuco vat dyeings of polypropylene (PP) fabrics in combinations of a trichromatic series of colorants (red, yellow and blue) plus an orange were performed in order to determine the compatibility of the component colorants in the developed single stage, batch exhaust dyeing process reported earlier. Cross-section micrographs of dyed fibers revealed the absence of "ring-dyeing". Tensile tests and X-ray crystallinity results confirmed that the developed dyeing process did not significantly...

Gupta, Murari L.; Fred Cook

2010-01-01

309

Study of the properties of polypropylene-PHB blends  

OpenAIRE

Polypropylene is ,with PVC and polyethylene, one of the most employed polymers for the production of daily life items. Although it is a thermoplastic polymer and nowadays the recycling conscience of the society is increasing, it is still found in urban wastes and therefore in landfills. Then, the main disadvantage is the permanence and the long life time of this type of plastics. The addition of biodegradable polymers has been claimed as a way to palliate this problem, since with degradation ...

Garci?a Quesada, Juan Carlos; Marcilla Gomis, Antonio; Barreiro Ortiz, Patricia; Gil Boj, Erika; Lo?pez Pastor, Miriam

2007-01-01

310

Light weight polarized polypropylene foam for noise shielding  

Science.gov (United States)

The high levels of noise generated during launch can destroy sensitive equipment on space craft. Passive damping systems, like acoustic blankets, work to reduce the high frequency noise but do little to the low frequency noise (loop feedback system will give a total damping effect that is adaptable over a wide band of low frequencies. This paper covers the manufacturing methods that were used to make polarized polypropylene foam, to test the foam for its polarized response and its noise shielding ability.

Zelfer, Travis J.; Warne, Derik S.; Korde, Umesh A.

2009-03-01

311

Morphology and mechanical properties of polypropylene-wood flour composites  

OpenAIRE

The microstructure and mechanical properties of polymer composites based on polypropylene and wood flour modified with monochloroacetic acid were investigated. Scanning electron microscopy and wide-angle X-ray diffraction were used as methods to probe the composite microstructures, while the tensile test was used to measure the physical strength. The wood flour modification was performed at different levels of monochloroacetic acid, ranging from 0.01 to 1 mol, while the modified wood flour ...

Vasileva, St; Nenkova, S.; Dobreva, D.

2006-01-01

312

Upgrading of recycled polypropylene by preparing flame retarded layered composite  

OpenAIRE

Upgrading of polypropylene waste was performed by different composite technologies, in order to improve the flame retardancy combined with preserved or improved mechanical properties. The polymer waste of density below 900 kg/m3 is originated from end-of-life vehicles (ELV) after comminution, density separation and comprehensive analysis. Intumescent flame retardant system was used for reducing the flammability; while chopped glass fibre reinforcement was used to compensate the deterioration ...

Ronkay, F.; Gy. Marosi; Toldy, A.; Bodzay, B.; Fejos, M.; Bocz, K.

2012-01-01

313

Modification of bentonite clay and application on polypropylene nano composites  

International Nuclear Information System (INIS)

This work consisted on the modification of Brasgel PA clay with ionic surfactant Praepagen WB and its incorporation into polypropylene. The results of infrared and DR-X was showed that the intercalation of surfactant in the clay and the incorporation of organoclay in PP matrix resulted in the formation of an intercalated structure. The impact strength of PP increased with the incorporation of organoclay. (author)

314

Mechanical and morphological characterization of polypropylene toughened with olefinic elastomer  

Scientific Electronic Library Online (English)

Full Text Available The effect of incorporating (C2-C8) ethylene-octene elastomer on the mechanical properties and morphology of polypropylene copolymers has been investigated employing two types of PP copolymer, with and without nucleating agent. The results were compared to the ones presented by a commercial PP heter [...] ophase (reactor impact modified PP/EPR). The addition of the elastomer increases the toughness of the blends but reduces their stiffness. PP blends in the low elastomer content region (

Cybele, Lotti; Carlos A., Correa; Sebastião V., Canevarolo.

2000-04-01

315

Compression of polypropylene across a wide range of strain rates  

Science.gov (United States)

Three grades of polypropylene were tested in uniaxial compression at room temperature, across a wide range of strain rate: 10-4 s-1 to 104 s-1. One grade is a conventional polypropylene homopolymer. The two other grades are the polypropylene forming the matrix phase of a continuous glass fibre-reinforced thermoplastic composite prepreg, with and without blending with a carbon-black master batch. Tests at the highest strain rates were performed using a compression split Hopkinson pressure bar. The test specimens, for all the three rates, were imaged using appropriate digital cameras in order to observe the deformation process. In addition, the images obtained were analysed digitally to obtain true strain measurements for the medium rates category. All three grades of polypropylene showed pronounced strain-rate dependence of compressive yield stress, increasing by factors of up to 4 across the range of rates. At the lowest rates, there was close agreement between the yield stresses for all three materials, and also close agreement with the Eyring theory. Considering the highest strain rates, however, yield stresses increased more rapidly with log(strain-rate) than would be expected from a linear Eyring prediction and values for the three materials diverged. This was attributed to the contributions made in each material by both alpha and beta relaxation processes. Also prominent in the medium- and high-rate experimental results was pronounced post-yield strain softening, greatest at the highest strain-rates. This resulted from a combination of thermal softening from adiabatic heating, and structural rejuvenation as often seen in glassy polymers in quasi-static tests.

Okereke, M. I.; Buckley, C. P.; Siviour, C. R.

2012-11-01

316

Effects of radiation on the structure of polypropylene  

International Nuclear Information System (INIS)

The effects of high-energy radiation on the physical arrangement of macromolecules in atactic polypropylene (aPP) and radiation-amorphized isotactic polypropylene (iPP) were examined using the differential radial distribution function (DRDF) technique. The resultant DRDF curve for 0 Mrad aPP showed three intermolecular peaks at 6.6, 13.0, and 17.7 A and two intramolecular peaks at 1.5 and 2.5 A. The appearance of the periodic intermolecular DRDF peaks suggested the packing of parallel chains of --18 A in the polymer. The 17.7 A peak disappeared when the aPP sample was irradiated to 115 Mrad, indicating the occurrence of structure deterioration from 18 A to 13 A. As a result of severe deterioration of the intermolecular organization, DRDF curves for 400 and 1300 Mrad iPP samples each showed only one intermolecular peak at --7 A. This deterioration was attributed to the crosslinking-induced increase in lattice distortions. The results were compared with previous studies on irradiation of natural rubber (NR) and polyethylene (PE). It appears that radiation was more effective in causing deterioration of the intermolecular organization in polypropylene than in NR and PE. This was explained by the different radiation chemistry of the polymers. (author)

317

Study of polypropylene/polybutene blends submitted to ionizing radiation  

International Nuclear Information System (INIS)

PP has been used in various applications instead of polyvinylchloride, polyurethane or polyethylene. However, PP as linear polymer exhibits low melt strength. One of the effective approaches to achieve high melt strength is to add chain branches onto backbone species using gamma radiation. Branching and grafting result from the macroradicals combinations during irradiation process. Crosslinking and main chain scission in the polymer structure are also obtained during this process. In this paper the gamma radiation technique was used to induce chemical changes in polypropylene/polybutene blends with an acetylene atmosphere. Acetylene was injected into polyethylene bags with polypropylene/polybutene blends. These samples were irradiated with a 60Co source from Embrarad, at doses of 12,5 and 20 kGy. The crosslinking of polymer was studied by measuring gel content and changes in the rheological properties of theses samples were observed as a function of melt strength and drawability obtained with a Rheotens apparatus and of melt index measurements. The polypropylene/polybutene blends showed a remarkable increase at drawability. (author)

318

Rheological study of polypropylene irradiated with polyfunctional monomers  

Energy Technology Data Exchange (ETDEWEB)

The aim of this paper is to investigate the rheological properties of polypropylene (PP) modified by ionization radiation (gamma rays) in the presence of two different monomers. The samples were mixed in a twin-screw extruder with ethylene glycol dimethacrylate (EGDMA) or trimethylolpropane trimethacrylate (TMPTMA) with concentration in the range of 0.5-5.0 mmol. After that, they were irradiated with 20 kGy dose of gamma radiation. The structural modification of polypropylene was analyzed in the melt state by measuring melt flow rate (MFR), {eta}* (complex viscosity) and G' (storage modulus) in the angular frequency range of 10{sup -1} to 3 x 10{sup 2} rad s{sup -1}. From the oscillatory rheology data, one could obtain the values of {eta}{sub 0} (zero shear viscosity) that would be related to the molar mass. All results were discussed with respect to the crosslinking and degradation process that occur in the post-reactor treatment to produce controlled rheology polypropylene. The resulting polymeric materials were submitted the cytotoxicity in vitro test by neutral red uptake methodology with NCTC L 929 cell line from American Type Culture Collection bank. All modified PP samples presented no cytotoxicity.

Otaguro, H.; Rogero, S.O.; Yoshiga, A.; Lima, L.F.C.P.; Parra, D.F. [IPEN/CNEN - Instituto de Pesquisas Energeticas e Nucleares, Av. Professor Lineu Prestes, 2242, CEP 05508-000 - Cidade Universitaria, Sao Paulo, SP (Brazil); Artel, B.W.H. [EMBRARAD - Empresa Brasileira de Radiacoes Ltda, Av. Cruzada Bandeirante, 269, CEP 06705-140 - Cotia (Brazil); Lugao, A.B. [IPEN/CNEN - Instituto de Pesquisas Energeticas e Nucleares, Av. Professor Lineu Prestes, 2242, CEP 05508-000 - Cidade Universitaria, Sao Paulo, SP (Brazil)], E-mail: ablugao@ipen.br

2007-12-15

319

Study of gel formation in polypropylene modified by gamma irradiation  

International Nuclear Information System (INIS)

The linearity of the chains of iPP (isotactic polypropylene) confers to this, low melt strength. This fact limits the use of iPP in processes that demand high stretching. The graft of branches confers improvements in its extensional viscosity, resulting in Polypropylene with High Melt Strength (HMS-PP). Preparation process of the HMS-PP, included iPP in pellets, conditioned in plastic container containing acetylene under pressure of 110 kPa and radiation with ? source of 60Co in the doses of 5, 12.5 and 20 kGy. The gel fraction of the samples was determined by the extraction of soluble components in xylene under boiling for 12 hours at 138 deg C. The soluble part of the samples was decanted with the total volatilization of the xylene to the room temperature (25 deg C) and deposition in glass blades. These samples had been characterized by Optic Microscopy, Scanning Electron Microscopy and Infrared Spectroscopy. In this study of the morphology, we obtained the formation of gel and microgel of polypropylene with higher incidence in HMS-PP 20 kGy. (author)

320

Rheological study of polypropylene irradiated with polyfunctional monomers  

International Nuclear Information System (INIS)

The aim of this paper is to investigate the rheological properties of polypropylene (PP) modified by ionization radiation (gamma rays) in the presence of two different monomers. The samples were mixed in a twin-screw extruder with ethylene glycol dimethacrylate (EGDMA) or trimethylolpropane trimethacrylate (TMPTMA) with concentration in the range of 0.5-5.0 mmol. After that, they were irradiated with 20 kGy dose of gamma radiation. The structural modification of polypropylene was analyzed in the melt state by measuring melt flow rate (MFR), ?* (complex viscosity) and G' (storage modulus) in the angular frequency range of 10-1 to 3 x 102 rad s-1. From the oscillatory rheology data, one could obtain the values of ?0 (zero shear viscosity) that would be related to the molar mass. All results were discussed with respect to the crosslinking and degradation process that occur in the post-reactor treatment to produce controlled rheology polypropylene. The resulting polymeric materials were submitted the cytotoxicity in vitro test by neutral red uptake methodology with NCTC L 929 cell line from American Type Culture Collection bank. All modified PP samples presented no cytotoxicity

321

Rheological study of polypropylene irradiated with polyfunctional monomers  

Science.gov (United States)

The aim of this paper is to investigate the rheological properties of polypropylene (PP) modified by ionization radiation (gamma rays) in the presence of two different monomers. The samples were mixed in a twin-screw extruder with ethylene glycol dimethacrylate (EGDMA) or trimethylolpropane trimethacrylate (TMPTMA) with concentration in the range of 0.5-5.0 mmol. After that, they were irradiated with 20 kGy dose of gamma radiation. The structural modification of polypropylene was analyzed in the melt state by measuring melt flow rate (MFR), ?* (complex viscosity) and G' (storage modulus) in the angular frequency range of 10 -1 to 3 × 10 2 rad s -1. From the oscillatory rheology data, one could obtain the values of ?0 (zero shear viscosity) that would be related to the molar mass. All results were discussed with respect to the crosslinking and degradation process that occur in the post-reactor treatment to produce controlled rheology polypropylene. The resulting polymeric materials were submitted the cytotoxicity in vitro test by neutral red uptake methodology with NCTC L 929 cell line from American Type Culture Collection bank. All modified PP samples presented no cytotoxicity.

Otaguro, H.; Rogero, S. O.; Yoshiga, A.; Lima, L. F. C. P.; Parra, D. F.; Artel, B. W. H.; Lugão, A. B.

2007-12-01

322

Mixing of Isotactic and Syndiotactic Polypropylenes in the Melt  

Energy Technology Data Exchange (ETDEWEB)

The miscibility of polypropylene (PP) melts in which the chains differ only in stereochemical composition has been investigated by two different procedures. One approach used detailed local information from a Monte Carlo simulation of a single chain, and the other approach takes this information from a rotational isomeric state model devised decades ago, for another purpose. The first approach uses PRISM theory to deduce the intermolecular packing in the polymer blend, while the second approach uses a Monte Carlo simulation of a coarse-grained representation of independent chains, expressed on a high-coordination lattice. Both approaches find a positive energy change upon mixing isotactic PP (iPP) and syndiotactic polypropylene (sPP) chains in the melt. This conclusion is qualitatively consistent with observations published recently by Muelhaupt and coworkers. The size of the energy chain on mixing is smaller in the MC/PRISM approach than in the RIS/MC simulation, with the smaller energy change being in better agreement with the experiment. The RIS/MC simulation finds no demixing for iPP and atactic polypropylene (aPP) in the melt, consistent with several experimental observations in the literature. The demixing of the iPP/sPP blend may arise from attractive interactions in the sPP melt that are disrupted when the sPP chains are diluted with aPP or iPP chains.

CLANCY,THOMAS C.; PUTZ,MATHIAS; WEINHOLD,JEFFREY D.; CURRO,JOHN G.; MATTICE,WAYNE L.

2000-07-14

323

Contact angle analysis of corona treated polypropylene films  

International Nuclear Information System (INIS)

In this work, the effect of the surface modification of polypropylene films via corona treatment was investigated. Polypropylene films were treated with negative and positive corona discharge, at atmospheric pressure, for 5 minutes, at two different temperatures – 25 °C and 90 °C. The changes in the surface free energy were investigated by means of contact angle measurements. The Bickerman's method was applied to determine the polar and dispersion components of the polymer surface free energy, on the basis of the theory of Owens, Wendt, Kaelble and Uy. Atomic force microscopy was used to analyze the polymer surface morphology changes of the films with temperature. According to the findings, in all cases the corona treatment increases the surface free energy of polypropylene films and its polar part, in comparison with the untreated samples. The effects of negative and positive corona polarities display some specific features which could be associated with different charged group introduced onto the film surface during the corona treatment. The total final effect depends on the simultaneous action of the two competing factors – temperature and corona polarity. The most pronounced effect was observed for high temperature negative corona treatment.

324

Development and characterisation of injection moulded, all-polypropylene composites  

Directory of Open Access Journals (Sweden)

Full Text Available In this work, all-polypropylene composites (all-PP composites were manufactured by injection moulding. Prior to injection moulding, pre-impregnated pellets were prepared by a three-step process (filament winding, compression moulding and pelletizing. A highly oriented polypropylene multifilament was used as the reinforcement material, and a random polypropylene copolymer (with ethylene was used as the matrix material. Plaque specimens were injection moulded from the pellets with either a film gate or a fan gate. The compression moulded sheets and injection moulding plaques were characterised by shrinkage tests, static tensile tests, dynamic mechanical analysis and falling weight impact tests; the fibre distribution and fibre/matrix adhesion were analysed with light microscopy and scanning electron microscopy. The results showed that with increasing fibre content, both the yield stress and the perforation energy significantly increased. Of the two types of gates used, the fan gate caused the mechanical properties of the plaque specimens to become more homogeneous (i.e., the differences in behaviour parallel and perpendicular to the flow direction became negligible.

A. Kmetty

2013-02-01

325

Property Relationship in Organosilanes and Nanotubes Filled Polypropylene Hybrid Composites  

Directory of Open Access Journals (Sweden)

Full Text Available Polypropylene composites with different filler contents were prepared by creating a masterbatch containing 3 wt%. filler. A variety of silanol groups were used to synthetized three compounds in different media trough a sol-gel process with acetic acid, formic acid and ammonium hydroxide as catalysts. Besides, four different nanotubular fillers were also used to analyze their behavior and compare it with the effect caused by the silanol groups. These tubular structures comprise: unmodified halloysite, carbon nanotubes and functionalized halloysite and carbon nanotubes. Morphological characterization in SEM and STEM/TEM showed dispersion in the polypropylene matrix. According to TGA and DSC measurements thermal behavior remain similar for all the composites. Mechanical test in tension demonstrate that modulus of the composites increases for all samples with a major impact for materials containing silanol groups synthetized in formic acid. Rheological measurements show a significantly increment in viscosity for samples containing unmodified and modified carbon nanotubes. No difference was found for samples containing silanol groups and halloysite when compared to neat polypropylene. Finally, the oxygen transmission rate increased for all samples showing high barrier properties only for samples containing natural and functionalized halloysite nanotubes.

Alejandra J. Monsiváis-Barrón

2014-10-01

326

Effect of ?-irradiation on the structure, stability and transport properties of polypropylene membrane and Cyanex-301  

International Nuclear Information System (INIS)

Polypropylene supported liquid membrane of Cyanex-301 was found to be promising for the separation of trivalent actinides and lanthanides. It is therefore important to study the effect of gamma radiation on the transport behaviour of polypropylene supported liquid membrane containing Cyanex-301 as carrier. In the present work polypropylene flatsheet and Cyanex-301 solution in dodecane were irradiated separately by gamma irradiation. The transport behavior of the SLM of the irradiated polypropylene flatsheets were correlated with its change in pore structure observed by scanning electron microscopy. (author)

327

Study on the method of identification of irradiated polypropylene by ESR spectroscopy  

International Nuclear Information System (INIS)

Electron spin resonance (ESR) signals were detected from irradiated polypropylene, which is widely used as packing material of food products. Optimum conditions were investigated for identifying irradiated food indirectly using ESR spectroscopy. From the ESR spectra, the g1, g2 and g3 factors for irradiated polypropylene were 2.0350±0.0002, 2.0089±0.0002 and 2.0052±0.0002, respectively. ESR intensity of irradiated polypropylene was positively correlated with microwave power, modulation amplitude and absorbed dose, and the detection limit was 0.5 kGy within 30 days post irradiation. The study provides a basis for identifying irradiated food products packed by polypropylene. (authors)

328

Robotic suture of a large caval injury caused by endo-GIA stapler malfunction during laparoscopic wedge resection of liver segments VII and VIII en-bloc with the right hepatic vein.  

Science.gov (United States)

Primary endo-GIA stapler malfunction occurred during robotic wedge resection of liver segments VII and VIII en-bloc with the right hepatic vein, in an obese woman diagnosed with single liver metastasis from a previous carcinoid tumour. Haemorrhage was soon controlled by clamping the vena cava below the injury using two wristed forceps angled at 90 degrees . With the two instruments locked in the holding position the ensuing operative strategy was discussed between surgeon and anaesthesia teams. Using the third robotic arm the caval injury was repaired laparoscopically with interrupted polypropylene sutures. The patient was transfused with two units of packed red blood cells, recovered uneventfully, and was discharged on post-operative day five. We conclude that even the most advanced technologies can fail and that surgeons should be fully aware of the consequences of these malfunctions and be prepared for repair. From this point of view, the da Vinci surgical system seems to have some advantages over classical laparoscopic methods including the ability to lock the wristed instruments in the holding position, the use of three arms by the same operating surgeon, and the extreme facilitation of intracorporeal suturing and knot-tying in deep and narrow spaces, extremely difficult if not impossible with conventional laparoscopic instruments. PMID:19707931

Boggi, Ugo; Moretto, Carlo; Vistoli, Fabio; D'Imporzano, Simone; Mosca, Franco

2009-01-01

329

Celastrol nanoparticles inhibit corneal neovascularization induced by suturing in rats  

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Full Text Available Zhanrong Li1, Lin Yao1, Jingguo Li2, Wenxin Zhang1, Xianghua Wu1, Yi Liu1, Miaoli Lin1, Wenru Su1, Yongping Li1, Dan Liang11State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, 2School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou, People's Republic of ChinaPurpose: Celastrol, a traditional Chinese medicine, is widely used in anti-inflammation and anti-angiogenesis research. However, the poor water solubility of celastrol restricts its further application. This paper aims to study the effect of celastrol nanoparticles (CNPs on corneal neovascularization (CNV and determine the possible mechanism.Methods: To improve the hydrophilicity of celastrol, celastrol-loaded poly(ethylene glycol-block-poly(?-caprolactone nanopolymeric micelles were developed. The characterization of CNPs was measured by dynamic light scattering and transmission electron microscopy analysis. Celastrol loading content and release were assessed by ultraviolet-visible analysis and high performance liquid chromatography, respectively. In vitro, human umbilical vein endothelial cell proliferation and capillary-like tube formation were assayed. In vivo, suture-induced CNV was chosen to evaluate the effect of CNPs on CNV in rats. Immunohistochemistry for CD68 assessed the macrophage infiltration of the cornea on day 6 after surgery. Real-time quantitative reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay were used to evaluate the messenger ribonucleic acid and protein levels, respectively, of vascular endothelial growth factor, matrix metalloproteinase 9, and monocyte chemoattractant protein 1 in the cornea.Results: The mean diameter of CNPs with spherical shape was 48 nm. The celastrol loading content was 7.36%. The release behavior of CNPs in buffered solution (pH 7.4 showed a typical two-phase release profile. CNPs inhibited the proliferation of human umbilical vein endothelial cells in a dose-independent manner and suppressed the capillary structure formation. After treatment with CNPs, the length and area of CNV reduced from 1.16 ± 0.18 mm to 0.49 ± 0.12 mm and from 7.71 ± 0.94 mm2 to 2.29 ± 0.61 mm2, respectively. Macrophage infiltration decreased significantly in the CNP-treated corneas. CNPs reduced the expression of vascular endothelial growth factor, matrix metalloproteinase 9, and monocyte chemoattractant protein 1 in the cornea on day 6 after suturing.Conclusion: CNPs significantly inhibited suture-induced CNV by suppressing macrophage infiltration and the expression of vascular endothelial growth factor and matrix metalloproteinase 9 in the rat cornea.Keywords: celastrol, PEG-b-PCL nanopolymeric micelles, corneal neovascularization, macrophages, VEGF, MMP-9

Li ZR

2012-03-01

330

Transcutaneous Serdev Suture For Buttock’s Lift  

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Full Text Available This article presents the author's technique and experience in the treatment of the flaccid "unhappy buttock" form with his surgical procedure of buttock lift by suture, without incision scars. The author first presented this new operation technique on a national level at the 2nd Annual Meeting of the National Bulgarian Society for Aesthetic Surgery and Aesthetic Medicine in Sofia on March 18, 1994 [1] and internationally at many scientific meetings over the world [2, 3, 4…]. The result is a visual change in the buttock position to a higher one, which elongates the lower limbs and changes the proportions between lower and upper half of the body. The aim of this study is to describe a mini-invasive procedure of beautification of the buttock form without scars by creating a lifting effect on the buttock's subcutaneous tissue, using a suture that takes the inferiorly positioned deep fibrose tissue and fixes it upwards to the sacro-cutaneous fascia, discovered by the author. Aesthetic and technical considerations required properly sculpting the buttocks into a higher position, demonstrating nicely rounded form. Preoperative shape is discussed and patient evaluations, operative techniques, postoperative management and results after 4 years of experience are emphasized. 1032 female patients, and 26 male patients aged 18-62 years, with ptosis and cellulite on the buttocks were treated since 1993 on an outpatient basis by the "Serdev suture technique without visible scars". Important instrumentarium is a long, curved, elastic needle and Polycon semi-elastic Bulgarian antimicrobial polycaproamide long term (in 2 years absorbable surgical threads Polycon, produced in Bulgaria. This operation has been performed either alone or after ultrasonic assisted liposculpture (UAL that reduces the amount of fat and heaviness. All patients reported a high degree of satisfaction. A stable improvement in the buttock position and form was observed for the period described. In the postoperative period the complication rate was minimal and resolved in the first 4-5 days post operative period. The skin puncture in the perianal zone makes antibiotic prophylaxis obligatory as well as a strict follow up for the first 7 days. Some pain in the sitting position was observed for at least 5 to 10 days, but all other social and professional duties and activities were possible. This outpatient procedure is effective in the correction of buttock laxity and ptosis and creates a new form, universally accepted as "happy buttocks".

Nikolay Serdev

2013-10-01

331

Stabilization of polypropylene, polypropylene blends with poly (styrene-b-(ethylene-co-butylene)-b-styrene) under irradiation: A comparative investigation  

Energy Technology Data Exchange (ETDEWEB)

The aim of this paper is to investigate the stabilization of polypropylene in the poly (styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS)/polypropylene (PP) blends under irradiation with respect to PP. The PP films, SEBS/PP films were subjected to electron beam irradiation and characterized by wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), gel permeation chromatography (GPC), and dynamic mechanical thermal analysis (DMTA). It demonstrated that upon irradiation, the molecular weight of PP had a pronounced decrease due to the major chain scission, and the minor chain cross-linking or chain branching occurred at the higher irradiation dose. Stabilization of PP was improved in the presence of SEBS, exhibiting an enhanced irradiation resistance.

Luan Shifang; Yang Huawei; Shi Hengchong; Zhao Jie [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Wang Jianwei [Shandong Weigao Group Medical Polymer Company Limited, Weihai 264209 (China); Yin Jinghua, E-mail: yinjh@ciac.jl.c [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

2011-01-15

332

Stabilization of polypropylene, polypropylene blends with poly (styrene-b-(ethylene-co-butylene)-b-styrene) under irradiation: A comparative investigation  

International Nuclear Information System (INIS)

The aim of this paper is to investigate the stabilization of polypropylene in the poly (styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS)/polypropylene (PP) blends under irradiation with respect to PP. The PP films, SEBS/PP films were subjected to electron beam irradiation and characterized by wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), gel permeation chromatography (GPC), and dynamic mechanical thermal analysis (DMTA). It demonstrated that upon irradiation, the molecular weight of PP had a pronounced decrease due to the major chain scission, and the minor chain cross-linking or chain branching occurred at the higher irradiation dose. Stabilization of PP was improved in the presence of SEBS, exhibiting an enhanced irradiation resistance.

333

Single-incision laparoscopic splenectomy with innovative gastric traction suture  

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Full Text Available Laparoscopic splenectomy is now the gold standard for patients with idiopathic thrombocytopenic purpura (ITP undergoing splenectomy. There are a few reports in literature on single-incision laparoscopic (SIL splenectomy. Herein, we describe a patient undergoing SIL splenectomy for ITP without the use of a disposable port device. We report a 20-year-old female patient with steroid-refractory ITP having a platelet count of 14,000/cmm who underwent a SIL splenectomy. Dissection was facilitated by the use of a single articulating grasper and a gastric traction suture and splenic vessels were secured at the hilum with an endo-GIA stapler. She made an uneventful postoperative recovery and was discharged on the second postoperative day. She is doing well with no visible scar at 8-month follow-up.

Srikanth G

2011-01-01

334

Effects of maleated polypropylene on the morphology, thermal and mechanical properties of short carbon fiber reinforced polypropylene composites  

International Nuclear Information System (INIS)

Highlights: ? Carbon fibers (CFs) are the most widely used advanced reinforcing fiber materials. ? Improvement of adhesion between polypropylene (PP) matrix and CF were aimed. ? PP matrix was modified by addition of maleic anhydride grafted PP (PP-g-MAH). ? Mechanical properties of the composites were improved by PP-g-MAH compatibilizer. ? Modification of matrix with PP-g-MAH was improved the interfacial adhesion. -- Abstract: The aim of this study was to determine the effect of the maleic anhydride grafted polypropylene (PP-g-MAH) on the properties of short carbon fiber (CF) reinforced polypropylene (PP) composites. The composites were prepared by melt blending and injection molding techniques at different percentages of CF. Tensile tests, hardness, differential scanning calorimeter (DSC) and scanning electron microscopy (SEM) were performed to characterize the physical and morphological properties of the prepared composites. It was observed from SEM photographs that modification with PP-g-MAH improved the interfacial adhesion between the carbon fibers and PP matrix. The ultimate tensile strength, hardness and modulus values of modified PP composites were higher compared to the values of CF reinforced PP composites. Melting temperature of all composites was not changed significantly with increasing CF content; however degree of crystallinity values were decreased with the increasing CF content level.

335

Achilles tendon suture deteriorates tendon capillary blood flow with sustained tissue oxygen saturation – an animal study  

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Full Text Available Abstract Background Treatment of ruptured Achilles tendons currently constitutes of conservative early functional treatment or surgical treatment either by open or minimal invasive techniques. We hypothesize that an experimental Achilles tendon suture in an animal model significantly deteriorates Achilles tendon microcirculation immediately following suturing. Methods Fifteen Achilles tendons of eight male Wistar rats (275–325 g were included. After preparation of the Achilles tendon with a medial paratendinous approach, Achilles tendon microcirculation was assessed using combined Laser-Doppler and spectrophotometry (Oxygen-to-see regarding: - tendinous capillary blood flow [arbitrary units AU] - tendinous tissue oxygen saturation [%] - tendinous venous filling pressure [rAU] The main body of the Achilles tendon was measured in the center of the suture with 50 Hz. 10 minutes after Achilles tendon suture (6-0 Prolene, a second assessment of microcirculatory parameters was performed. Results Achilles tendon capillary blood flow decreased by 57% following the suture (70 ± 30 AU vs. 31 ± 16 AU; p Conclusion Achilles tendon suture in anaesthetised rats causes an acute loss of capillary perfusion and increases postcapillary venous filling pressures indicating venous stasis. The primary hypothesis of this study was confirmed. In contrast, tendinous tissue oxygen saturation remains unchanged excluding acute intratendinous hypoxia within the first 10 minutes after suture. Further changes of oxygen saturation remain unclear. Furthermore, it remains to be determined to what extent reduced capillary blood flow as well as increased postcapillary stasis might influence tendon healing from a microcirculatory point of view in this animal setting.

Vogt Peter M

2009-08-01

336

Immunostimulatory sutures that treat local disease recurrence following primary tumor resection  

International Nuclear Information System (INIS)

Neuroblastoma is a common childhood cancer that often results in progressive minimal residual disease after primary tumor resection. Cytosine-phosphorothioate-guanine oligonucleotides (CpG ODN) have been reported to induce potent anti-tumor immune responses. In this communication, we report on the development of a CpG ODN-loaded suture that can close up the wound following tumor excision and provide sustained localized delivery of CpG ODN to treat local disease recurrence. The suture was prepared by melt extruding a mixture of polylactic acid-co-glycolic acid (PLGA 75:25 0.47 dL g-1) pellets and CpG ODN 1826. Scanning electron microscopy images showed that the sutures were free of defects and cracks. UV spectrophotometry measurements at 260 nm showed that sutures provide sustained release of CpG ODN over 35 days. Syngeneic female A/J mice were inoculated subcutaneously with 1 x 106 Neuro-2a murine neuroblastoma wild-type cells and tumors were grown between 5 to 10 mm before the tumors were excised. Wounds from the tumor resection were closed using CpG ODN-loaded sutures and/or polyglycolic acid Vicryl suture. Suppression of neuroblastoma recurrence and mouse survival were significantly higher in mice where wounds were closed using the CpG ODN-loaded sutures relative to all other groups. (communication)

337

Experimental studies on the influence of irradiation (60Co) on wound healing of colonic suture  

International Nuclear Information System (INIS)

Effects of preoperative 60Co irradiation on wound healing of colonic suture in adult dogs of mixed breed were discussed. Wound healing 7 days after colonic suture was compared among dogs which received colonic suture immediately, or 3 days, or 7 days after the 60Co irradiation. As a result, there was not a big difference in their wound healing among these dogs, and disorders of wound healing were not found. Bursting pressure at sutured sites was always lower in irradiated dogs than controls. Recovery of the bursting pressure was 2 days slower in irradiated dogs than non-irradiated dogs for 7 days after the suture. Bursting pressure was the lowest on the 3rd day after the suture in both groups. As to fine changes in irradiated dogs, appearance of recommunicating phenomena in blood vessels, delay of a decrease in avascular regions, delay of granulation, and hypertrophy of vascular walls seemed to be influenced by 60Co irradiation, but there was not a big difference in these results between irradiated and non-irradiated dogs. An increase in postoperative concentration of hydroproline tended to be little lower in irradiated dogs than controls, which seemed to be influenced by the 60Co irradiation. This result was also suggested from delay of granulation and remaining inflammations. Effects of 60Co irradiation on wound healing of colonic suture seemed to be slight generally, because ruptured suture scarecely occurred icause ruptured suture scarecely occurred in the irradiated dogs. When doses used in this experiment were calculated roughly by Ellis's method, irradiation of 60Co seemed not to influence seriously wound healing if the total of 2,000 to 2,500 rad was irradiated in 8 to 10 doses to human colon. (Tsunoda, M.)

338

Non infective severe aortic paravalvular leakage 7 years after surgery: the role of suture technique  

OpenAIRE

Abstract We report a case of redo aortic prosthesis replacement for a severe paravalvular leak (PVL) in a man operated with continuous suture technique 7 years earlier. The severe aortic regurgitation was due to the rupture of the suture. In spite of operations to replace malfunctioning heart valves are common procedures and performed all over the world from more than 50 years, there is still an open debate about the most suitable suture technique. In this case report, we'll discuss if the su...

Gregorini Luisa; Zanobini Marco; Roberto Maurizio; Filippini Sara; Agrifoglio Marco; Alamanni Francesco

2011-01-01

339

Changes to the chemical structure of isotactic-polypropylene induced by ion-beam irradiation  

International Nuclear Information System (INIS)

The chemical structures of various ion-beam irradiated isotactic-polypropylene samples were studied. Results of micro-Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy suggest not only the linear energy transfer, but also the fluence is effective in local transformation of the isotactic-polypropylene.

340

The effect of antioxidants on the morphology of gamma irradiated isotactic polypropylene  

Energy Technology Data Exchange (ETDEWEB)

The effect of two types of antioxidants on the morphology and melting behaviour of gamma irradiated isotactic polypropylene has been studied using X-ray diffraction and differential scanning calorimetry. The changes in the morphology and decrease of melting temperature and crystallinity with absorbed dose are related to the radiation processes in isotactic polypropylene (IPP) containing antioxidants. (author).

Kostoski, D.; Stojanovic, Z.; Kacarevic-Popovic, Z. (Institut za Nuklearne Nauke Boris Kidric, Belgrade (Yugoslavia))

1990-01-01

341

GC-MS OF POLYETHYLENE AND POLYPROPYLENE THERMAL CRACKING PRODUCTS  

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Full Text Available Low-density polyethylene and polypropylene were thermally decomposed individually in a batch reactor at 450°C as a recycling route from the aspect of the production of petrochemical feedstock. The resulting transformation liquid products were analysed by high resolution gas chromatographic-mass spectrometric analysis. More detailed separation of polyalkenes splitting compounds was achieved using high resolution GC (efficiencies up to 490 000 plates than before. The GC-MS as well as the dependence of homomorphy factors and isopropyl group increments on the number of carbon atoms of alk-1-enes, alk-2-enes, alka-?,?-dienes and alkanes were used for identification of separated analytes.Thermal cracking of LDPE products in the range C5-C23 were characterized by quintets of peaks in the chromatogram which were assigned to n-alkanes, alk-1-enes, (E-alk-2-enes, (Z-alk-2-enes and alka-?,?-dienes with average quantitative ratio 1 : 1.2 : 0.07 : 0.05 : 0.08. In fraction up to n-C8 140 GC peaks were separated and identified, including around 30 acyclic octenes.In contrast to the polyethylene thermal cracking which yields products with straight-chain hydrocarbon structure, polypropylene cracking is characterized by the formation of compounds with branched and high prevailingly unsaturated hydrocarbon structure. The pretention of this analytical problem lies in stereoisomerism and corresponding multicomponentity of branched alkenes, alkadienes and alkanes in a broad range of carbon atoms number as main decomposition products of polypropylene. In the liquid fraction up to n-C8 84 peaks including around 40 acyclic octenes were identified. Other 149 GC peaks were analysed in the C9-C25 fraction with quantitative ratio of alkane : alkene : alkadiene equal to 1 : 17 : 4. High resolution GC allowed more detailed and more reliable analysis of multicomponent polyalkenes cracking products.

Martin Bajus

2006-03-01

342

Use of polypropylene mesh in hernioplasty by Lichtenstein's technique  

International Nuclear Information System (INIS)

INTRODUCTION. The aim of present study was to assess the benefit using the prosthesis (polypropylene mesh) in the hernioplasty using the Lichtenstein's technique in the 'Joaquin Albarran' Clinical Surgical Hospital. METHODS. A prospective study (with an interval of 14 months) was conducted in 140 surgical interventions carried out using the Lichtenstein's technique in patients presenting with inguinal hernia. One hundred and ten patients were excluded due to interventions were of ambulatory method. The following data were studied: type of hernia found in the physical examination, age, sex, and race, type of job, intervention's date, and technique used as well as the complications during the immediate postoperative time. Also, the hernia's relapse after operation, surgical complications and tolerance to polypropylene mesh were taking into account. RESULTS. There was predominance of male sex confirming a direct influence among types of jobs requiring a strong physical effort and the appearance of inguinal hernias (63,3 %). There were only three complications: a hematoma and two seromas. There were not relapses and any case of infection, both local and systemic. The use of prophylactic antibiotics showed an appropriate cost-benefit relationship. CONCLUSIONS. The old age, the male sex and a sustained physical effort have a directly proportional relation to appearance of inguinal hernias. The feasibility of Lichtenstein's hernioplasty, the null incidence of hernia relapsessty, the null incidence of hernia relapses and no appearance of complications including the rejection to prosthetic material, favoured the use of polypropylene in this plasty. Authors recommended the use of perioperative prophylactic antibiotic therapy to avoid wound's infection and thus to secure the result of surgical intervention and its durability. (author)

343

Tribological properties of polypropylene composites with carbon nanotubes and sepiolite.  

Science.gov (United States)

Carbon nanotubes (CNTs) and sepiolite (SEP) were modified in order to improve their compatibility with the polypropylene (PP) matrix. Carboxylic groups were introduced into the CNTs through an oxidative treatment and aliphatic chains were incorporated on SEP by ion exchange of a cationic surfactant. Maleic anhydride grafted polypropylene (PPgMA) was mixed with neat PP to introduce polar groups into the polymer matrix. Composites including modified and non-modified fillers were prepared by melt extrusion. Dispersion and interaction of the CNTs with the PP and PPgMA matrices were evaluated by Raman spectroscopy while a focused ion beam/scanning electron microscopy (FIB/SEM) was used for SEP containing composites. Scratch resistance, microhardness, dynamic friction and wear were determined. Raman spectroscopy shows that the introduction of polar groups into PP matrices has a positive effect on the dispersion of modified CNTs. FIB/SEM results show that the modification of SEP improves its dispersion in the polypropylene matrix; filler clusters found in the PPgMA matrix are much times smaller than those in the neat PP. Despite of SEP agglomerates in the composites, a good interaction between both phases is seen; SEP particles are fully coated and embedded inside the PP matrix. The 'lack of cooperation' between unmodified PP and its fillers results in nanocomposites with larger residual depths; by contrast, PPgMA does 'cooperate' with its fillers so that the nanocomposites in scratch resistance testing have smaller residual depths R(h) than the neat PPgMA. Addition of the fillers to PPgMA also increases the hardness. As for wear rates, some our fillers provide higher and some lower wear rates than PP. PMID:24757963

Orozco, Victor H; Vargas, Andres F; Brostow, Witold; Datashvili, Tea; López, Betty L; Mei, Kevin; Su, Lisa

2014-07-01

344

Conversion of atactic polypropylene waste to fuel oil. Final report  

Energy Technology Data Exchange (ETDEWEB)

A stable, convenient thermal pyrolysis process was demonstrated on a large scale pilot plant. The process successfully converted high viscosity copolymer atactic polypropylene to predominantly liquid fuels which could be burned in commercial burners. Energy yield of the process was very high - in excess of 93% including gas phase heating value. Design and operating data were obtained to permit design of a commercial size atactic conversion plant. Atactic polypropylene can be cracked at temperatures around 850/sup 0/F and residence time of 5 minutes. The viscosity of the cracked product increases with decrease in time/temperature. A majority of the pyrolysis was carried out at a pressure of 50 psig. Thermal cracking of atactic polypropylene is seen to result in sigificant coke formation (0.4% to 0.8% on a weight of feed basis) although the coke levels were of an order of magnitude lower than those obtained during catalytic cracking. The discrepancy between batch and continuous test data can be atrributed to lowered heat transfer and diffusion rates. Oxidative pyrolysis is not seen as a viable commercial alternative due to a significant amount of water formation. However, introduction of controlled quantities of oxygen at lower temperatures to affect change in feedstock viscosity could be considered. It is essential to have a complete characterization of the polymer composition and structure in order to obtain useful and duplicable data because the pyrolysis products and probably the pyrolysis kinetics are affected by introduction of abnormalities into the polymer structure during polymerization. The polymer products from continuous testing contained an olefinic content of 80% or higher. This suggests that the pyrolysis products be investigated for use as olefinic raw materials. Catalytic cracking does not seem to result in any advantage over the Thermal Cracking process in terms of reaction rates or temperature of operation.

Bhatia, J.

1981-04-01

345

Physical and Mechanical Properties of Natural Fibers Filled Polypropylene Composites and Its Recycle  

Directory of Open Access Journals (Sweden)

Full Text Available This study discusses the influence of natural fiber type on the performance of polypropylene and its recycle. Composites consisting of polypropylene (PP and natural fiber from wood (Acacia mangium, water hyacinth (Eichornia crassipes, kenaf (Hibiscus cannabinus, banana (Musa paradisiaca and empty fruit bunch of oil palm (Elaeis guineensis were prepared by extrusion and compression process based on the ratio of 50:50% (w/w with the addition of 2.5% polypropylene modified with maleic anhydride (MAPP. The effect of fiber type on the composites was evaluated. Physical and mechanical properties were studied. The composite showed significantly different properties based on the fiber type. Kenaf filled composite showed high tensile strength, break strain and modulus of elasticity properties but least absorbed water. Banana fiber filled propylene composite is comparable with that of kenaf. In general, recycle polypropylene can replace virgin polypropylene since their natural fibers filled composites showed similar mechanical and physical properties.

Myrtha Karina

2007-01-01

346

Polypropylene Track Membranes for Mikro and Ultrafiltration of Chemically Aggressive Agents  

CERN Document Server

A production process for track membranes on the basis of chemically resistant polymer polypropylene has been developed. Research in all stages of the formation of the polypropylene track membranes has been conducted: the main principles of the process of chemical etching of polypropylene irradiated with accelerated ions have been investigated, the most effective structure of the etchant for a selective etching of the heavy ion tracks has been selected, the parameters of etching have been optimized. A method for sensibilization of latent tracks in polypropylene by effect of solvents has been developed. It helps to reach a significant increase in etching selectivity. A method for destruction of an absorbed chromocontaining layer on the surface of polypropylene track membranes formed during etching has been elaborated. Experimental samples of the membranes for micro and ultrafiltration have been obtained and their properties have been studied in course of their exploitation in chemically aggressive agents. For t...

Kravets, L I; Apel, P Yu

2000-01-01

347

Raman Spectra and Mechanical Properties of Graphene/Polypropylene Nanocomposites  

OpenAIRE

Graphene/Polypropylene nanocomposites were prepared at different filler loading and different average surface diameter 5, 15 and 25?m of graphene nanoplatelets by using Haake Minilab mixer at 180oC and rotor speed 50rpm. Besides, Haake MiniJet is used to obtain dumbbell shape specimen. The effect of filler loading and average surface area of filler in PP/GnP composites on Raman spectrum and tensile properties were studied. Raman spectrum of graphene particles indicate three major spectrums s...

Ahmad, Siti R.; Young, Robert J.; Kinloch, Ian A.

2015-01-01

348

Co-pyrolysis of polypropylene waste with Brazilian heavy oil.  

Science.gov (United States)

To evaluate the chemical recycling of plastic residues, co-pyrolysis of polypropylene (PP) waste with Brazilian crude oil was evaluated varying the temperature (400°C to 500°C) and the amount of PP fed to the reactor. The co-pyrolysis of plastic waste in an inert atmosphere provided around 80% of oil pyrolytic, and of these, half represent the fraction of diesel oil. This study can be used as a reference in chemical recycling of plastics, specially associated with plastics co-pyrolysis. PMID:21409698

Assumpção, Luiz C F N; Carbonell, Montserrat M; Marques, Mônica R C

2011-01-01

349

Morphology-mechanical Property Relationship of Polypropylene/starch Blends  

OpenAIRE

The influence of morphology on mechanical property of several polypropylene/starch (PP/starch) blends of varying compositions was studied. The blends prepared were at wt%PP/wt%starch of 97.5/2.5, 95/5, 92.5/7.7, 90/10, 87.5/12.5 and 85/15. The morphology of the blends observed, using scanning electron microscopy showed them to be immiscible blends with distinct polymer-starch domains at high starch volume fractions (85%PP/15%starch-87.5%PP/12.5%starch), which gradually showed the morphology o...

Azhari, C. H.; Wong, S. F.

2001-01-01

350

Rheological behaviour of polypropylene blends utilized in foaming process.  

Czech Academy of Sciences Publication Activity Database

Athens : WSEAS, 2010 - (Martin, O.; Zheng, X.), s. 275-278 ISBN 978-960-474-203-5. ISSN 1792-4294. - (Mathematics and Computers in Science Engineering). [WSEAS International Conference on Engineering Mechanics, Structures, Engineering Geology /3./ (EMESEG '10), International Conference on Geography and Geology 2010 (WORLDGEO '10). Corfu (GR), 22.07.2010-24.07.2010] Grant ostatní: GA MPO(CZ) 2A-1TP1/126 Institutional research plan: CEZ:AV0Z20600510 Keywords : polypropylene foam * rheology * strain hardening * foam morphology * pressure dependent viscosity Subject RIV: BK - Fluid Dynamics

Piyamanocha, P.; Sedlá?ek, T.; Polášková, M.; Filip, Petr; Sáha, P.

351

Polypropylene-polyethylene blends modified by gamma radiation  

International Nuclear Information System (INIS)

One way to obtain a better mechanical property of polypropylene and polyethylene is to increasing the number of polymer chains cross-linked by gamma radiation. After irradiation a network is formed as a result of various chemical reactions and the radicals formed are concentrated in the amorphous phase. With the objective to improve the mechanical properties of PP, blends with PE were prepared and irradiated in doses up to 500 kGy, in atmospheric ambient. The molecular characterization of the blends was made by infrared spectroscopy and the data showed an increase in rigidity and a unique behaviour in Izod impact resistance. (author)

352

Characterization of Fibers Produced from Blends of Polybutylene and Polypropylene  

OpenAIRE

Blends of polybutylene (PB-1) and polypropylene were used to produce fibers at spinning speeds of 800-2100 m/min. Concentrations ranged from 0% PP to 100% PP. The stress-strain behavior of the resultant fibers was examined, and the fibers were analyzed for crystallinity via DSC (differential scanning calorimetry). Fibers produced from blends of PB-1/PP show mechanical properties that are in between the properties of the pure polymers. The tensile strength of 50% PB-1 fibers is comparable to t...

Robert L Shambaugh, Ph D.; Ortiz, Diana L.

2007-01-01

353

Synthesis of Flame-Retardant Polypropylene/LDH-Borate Nanocomposites  

OpenAIRE

New nanocomposites have been prepared using unmodified polypropylene (PP) and a new type of highly dispersed [Zn2Al(OH6)][B 4O5(OH)4]0.5 (Zn2Al- borate) and [Mg3Al(OH)8][B4O 5(OH)4]0.5 (Mg3Al-borate) layered double hydroxides (LDHs). PP/LDHs nanocomposites with LDH loadings of 1, 3, 6, 9, 15, and 30 wt % have been prepared by a novel solvent mixing method. Scanning electron microscopy (SEM) analysis shows that the precipitated nanocomposites materials form spherical particles with an average ...

Wang, Q.; Undrell, Jp; Gao, Y.; Cai, G.; Buffet, J-c; Wilkie, Ca; O Hare, D.

2013-01-01

354

Radiation Damage of Polypropylene Fiber Targets in Storage Rings  

CERN Document Server

Thin polypropylene (CH$_2$) fibers have been used for internal experiments in storage rings as an option for hydrogen targets. The change of the hydrogen content due to the radiation dose applied by the circulating proton beam has been investigated in the range $1\\cdot10^6$ to $2\\cdot10^8$~Gy at beam momenta of 1.5 to 3 GeV/c by comparing the elastic pp-scattering yield to that from inelastic p-carbon reactions. It is found that the loss of hydrogen as a function of applied dose receives contributions from a fast and a slow component.

Rohdjess, H; Bisplinghoff, J; Bollmann, R; Büsser, K; Diehl, O; Dohrmann, F; Engelhardt, H P; Eversheim, P D; Greiff, J; Gross, A; Gross-Hardt, R; Hinterberger, F; Igelbrink, M; Langkau, R; Maier, R; Mosel, F; Müller, M; Muenstermann, M; Prasuhn, D; Von Rossen, P; Scheid, H; Schirm, N; Schwandt, F; Scobel, W; Trelle, H J; Wellinghausen, A; Wiedmann, W; Woller, K; Ziegler, R

2004-01-01

355

Elastic properties of highly anisotropic thin poly(propylene) foams  

OpenAIRE

In this letter, elastic properties of highly anisotropic cellular poly(propylene) films are reported. The material shows peculiar elastic properties compared to other foams in the literature. The data is displayed as the relative Young's modulus $E^*/E_s$ versus relative density $\\rho^*/\\rho_s$. Almost all the data from the literature are located on the region $E^*/E_s=(\\rho^*/\\rho_s)^n$ with $1\\le n\\le6$. The introduced material on the other hand have lower relative Young's...

Tuncer, Enis; Wegener, Michael

2004-01-01

356

Polypropylene/organoclay/SEBS nanocomposites with toughness-stiffness properties  

DEFF Research Database (Denmark)

Polypropylene nanocomposites with a different amount of styrene-ethylene-butylene-styrene block copolymer (SEBS)/clay were prepared via a melt mixing technique. To improve the dispersion of commercial organoclay (denoted as OMMT), various amounts of SEBS were incorporated. At a fixed content of OMMT, the mechanical properties were improved with increasing SEBS content. The obtained nanocomposites were characterized through X-ray diffraction (XRD), differential scanning calorimetry (DSC-TG) and mechanical tests. The thermal-morphological-mechanical properties were investigated. The nanomaterials presented an improved decomposition temperature, a small decrease in tensile strength, a higher Young's modulus and a spectacular increase of 300% in impact strength.

Sanporean (nee Potarniche), Catalina-Gabriela; Vuluga, Zina

2014-01-01

357

Study of irradiation effect on positronium formation in polypropylene  

Science.gov (United States)

60Co ?-rays and positron irradiation effect on positronium (Ps) formation in the bulk and near surface region of polypropylene (PP) was studied. It is revealed that the reduction of Ps formation probability in PP bulk as a function of elapsed time may not be due to enhanced concentration of oxygen groups, and should not be ascribed to a simple accumulation of free radicals. Results indicate that Ps in PP is not formed through only one branch. That branch sensitive to the irradiation as well as the existence of sample surface seems related to relatively mobile positrons.

Yu, R. S.; Suzuki, T.; Djourelov, N.; Ito, Y.; Kondo, K.

2006-02-01

358

Study of irradiation effect on positronium formation in polypropylene  

International Nuclear Information System (INIS)

6Co ?-rays and positron irradiation effect on positronium (Ps) formation in the bulk and near surface region of polypropylene (PP) was studied. It is revealed that the reduction of Ps formation probability in PP bulk as a function of elapsed time may not be due to enhanced concentration of oxygen groups, and should not be ascribed to a simple accumulation of free radicals. Results indicate that Ps in PP is not formed through only one branch. That branch sensitive to the irradiation as well as the existence of sample surface seems related to relatively mobile positrons

359

Study of irradiation effect on positronium formation in polypropylene  

Energy Technology Data Exchange (ETDEWEB)

{sup 6}Co {gamma}-rays and positron irradiation effect on positronium (Ps) formation in the bulk and near surface region of polypropylene (PP) was studied. It is revealed that the reduction of Ps formation probability in PP bulk as a function of elapsed time may not be due to enhanced concentration of oxygen groups, and should not be ascribed to a simple accumulation of free radicals. Results indicate that Ps in PP is not formed through only one branch. That branch sensitive to the irradiation as well as the existence of sample surface seems related to relatively mobile positrons.

Yu, R.S. [Radiation Science Center, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)]. E-mail: runsheng@post.kek.jp; Suzuki, T. [Radiation Science Center, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Djourelov, N. [Radiation Science Center, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Ito, Y. [Radiation Science Center, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Kondo, K. [Radiation Science Center, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

2006-02-15

360

21 CFR 878.5000 - Nonabsorbable poly(ethylene terephthalate) surgical suture.  

Science.gov (United States)

...ethylene terephthalate) surgical suture. 878.5000 Section 878.5000 Food and Drugs FOOD AND DRUG ADMINISTRATION...PLASTIC SURGERY DEVICES Surgical Devices § 878.5000 Nonabsorbable poly(ethylene terephthalate)...

2010-04-01

361

Barbed sutures in total knee arthroplasty: are these safe, efficacious, and cost-effective?  

Science.gov (United States)

The use of barbed sutures has become increasingly popular; however, their efficacy and safety continues to be debated. We review the records of 333 primary total knee arthroplasties (TKAs) to determine the difference in wound closure and total operative time between patients closed with a barbed versus standard sutures. We also evaluated complication rates and cost differences between the two groups. Overall, we saw no significant difference in either wound closure time (31 vs. 30 minutes) or total operative time (115 vs. 114 minutes). No significant differences were observed in the complication rate. Material costs were lower overall in the barbed suture group ($66.78 vs. 82.59). Further studies will be required to determine the role of barbed sutures in TKA. PMID:24764228

Maheshwari, Aditya V; Naziri, Qais; Wong, Andy; Burko, Ivan; Mont, Michael A; Rasquinha, Vijay J

2015-04-01

362

Monitoring of sutured flexor tendons using spectral domain optical coherence tomography  

Science.gov (United States)

The material behaviour of sutured tendons is important in healing models as mechanical trauma to the tendon during surgery can compromise the healing process. This work demonstrates the use of spectral domain optical coherence tomography (SD-OCT) for the monitoring of normal and injured, and subsequently repaired flexor tendons and their behaviour under load. Vertical crimp patterns in normal tendons were observed to be replaced by uniform scattering as the load increases, but the crimp periods in sutured tendons were constrained at the suture site, with gap separation at the suture joint tapering off at high loads. This information could be useful for surgeons who need to balance gap separation in healing tendons and sustainable load.

Tay, Chia-Meng B.; Chow, Tzu-Hao; Ng, Beng-Koon; He, Min; Gan, Wei-Tat A.; Chong, Khin-Sze A.

2010-02-01

363

Deformation and sedimentation along a developing terrane suture: Eastern Sunda forearc, Indonesia  

Science.gov (United States)

The collision of the eastern Sunda arc with northwest Australia has resulted in the development of a suture between the Sumba ridge and Sawu-Timor terrenes along a zone of intraforearc convergence. The developing suture varies from the low-angle Sawu thrust, with attendant mud diapirs in the Sumba basin, to high-angle reverse faults near a basement: high of the underthrust Sumba ridge terrane. Bottom currents, associated with the flow of Pacific Ocean deep water into the Indian Ocean, have eroded the terrenes and subsequently deposited the detritus in an assemblage of contourites along the suture. This study reveals the high structural variability of a terrane suture and the oceanographic influence on trie deposition of overlap assemblages.

Reed, Donald L.; Silver, Eli A.; Prasetyo, Hardi; Meyer, Audrey W.

1986-12-01

364

Suture-related keratitis following cataract surgery caused by methicillin-resistant Staphylococcus aureus  

Directory of Open Access Journals (Sweden)

Full Text Available Ahmad B Tarabishy1, Thomas L Steinemann21Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA; 2Cornea and External Eye Disease, MetroHealth Medical Center, Case Western Reserve University, Cleveland, OH, USAAbstract: A 54-year old-man presented with a two-day history of severe pain and decreased vision. Examination revealed a corneal ulcer associated with a loose suture from cataract surgery done approximately two years ago. The suture was removed and the patient was started on topic antibiotic treatment with cefazolin and gentamycin. Cultures revealed methicillin-resistant Staphylococcus aureus (MRSA. The antibiotic regimen was changed to include vancomycin but the ulcer continued to progress. Three days later, the ulcer had perforated and an emergent corneal patch graft was performed. To our knowledge, this is the first reported case of suture-related MRSA keratitis after uncomplicated clear corneal cataract surgery.Keywords: keratitis, MRSA, suture, staphylococcus aureus

Ahmad B Tarabishy

2010-03-01

365

Delayed primary suture of flexor tendons cut in the digital theca.  

Science.gov (United States)

The results of delayed primary suture of flexor tendons cut in the digital theca in twenty five patients, thirty three affected fingers, are given. The patients had their skin closed at another hospital immediately after the injury. One to six days later the skin stitches were removed and tendon suture was performed. Excellent and very good results are obtained in 79.7% of all thirty three fingers operated upon. PMID:6997144

Matev, I; Karagancheva, S; Trichkova, P; Tsekov, P

1980-06-01

366

Suture-related keratitis following cataract surgery caused by methicillin-resistant Staphylococcus aureus  

OpenAIRE

Ahmad B Tarabishy1, Thomas L Steinemann21Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA; 2Cornea and External Eye Disease, MetroHealth Medical Center, Case Western Reserve University, Cleveland, OH, USAAbstract: A 54-year old-man presented with a two-day history of severe pain and decreased vision. Examination revealed a corneal ulcer associated with a loose suture from cataract surgery done approximately two years ago. The suture was removed and the patient was started on topic ant...

Tarabishy, Ahmad B.; Steinemann, Thomas L.

2010-01-01

367

A Comparative In Vivo Study of Tissue Reactions to Four Suturing Materials  

OpenAIRE

INTRODUCTION: The purpose of this study was to compare the histopathologic reaction of four suturing materials: silk, polyvinylidene fluoride (PVDF), polyglycolic acid, and catgut in the oral mucosa of albino rabbits. MATERIALS AND METHODS: The twenty-one male mature albino rabbits which were used in this study were randomly divided into three groups of seven each. Silk, PVDF, polyglycolic acid and catgut suture materials were tested in the oral mucosa of these animals. The animals were sacri...

Shahla Kakoei; Fahimeh Baghaei; Shahriar Dabiri; Masoud Parirokh; Sina Kakooei

2010-01-01

368

Differential Expression of Extracellular Matrix-Mediated Pathways in Single-Suture Craniosynostosis  

OpenAIRE

Craniosynostosis is a disease defined by premature fusion of one or more cranial sutures. The mechanistic pathology of single-suture craniosynostosis is complex and while a number of genetic biomarkers and environmental predispositions have been identified, in many cases the causes remain controversial and inconclusive. In this study, gene expression data from 199 patients with isolated sagittal (n?=?100), unilateral coronal (n?=?50), and metopic (n?=?49) synostosis are compared a...

Stamper, Brendan D.; Park, Sarah S.; Beyer, Richard P.; Bammler, Theo K.; Farin, Frederico M.; Mecham, Brig; Cunningham, Michael L.

2011-01-01

369

The Roman Bridge: a "double pulley – suture bridges" technique for rotator cuff repair  

OpenAIRE

Abstract Background With advances in arthroscopic surgery, many techniques have been developed to increase the tendon-bone contact area, reconstituting a more anatomic configuration of the rotator cuff footprint and providing a better environment for tendon healing. Methods We present an arthroscopic rotator cuff repair technique which uses suture bridges to optimize rotator cuff tendon-footprint contact area and mean pressure. Results Two medial row 5.5-mm Bio-Corkscrew suture anchors (Arthr...

Maffulli Nicola; Rizzello Giacomo; Ruzzini Laura; Longo Umile; Franceschi Francesco; Denaro Vincenzo

2007-01-01

370

A novel technique of rotator cuff repair using spinal needle and suture loop  

OpenAIRE

Abstract Background We present a simple technique of arthroscopic rotator cuff repair using a spinal needle and suture loop. Methods With the arthroscope laterally, a spinal needle looped with PDS is inserted percutaneously into the shoulder posteriorly and penetrated through the healthy posterior cuff tear margin. Anteriorly, another spinal needle loaded with PDS is inserted percutaneously to engage the healthy tissue at the anterior tear margin. The suture in the anterior needle is then del...

Muzaffar Nasir; Yoon Jung-Ro; Kim Youngbae B

2010-01-01

371

Provenance of the Indus-Yarlung Suture Mélange and the Location of the India-Asia Suture, Southern Tibet  

Science.gov (United States)

The Indus-Yarlung Suture Zone (IYSZ) is the boundary between rocks of Indian and Asian affinity. From north to south in southern Tibet, it exposes the preserved Asian forearc, ophiolitic rocks, tectonic mélanges, and Tethyan Himalayan strata of Indian affinity. The mélange has long been considered the accretionary prism corresponding to the ophiolite to the north which obducted onto the Indian margin prior to India-Asia collision. An outstanding issue is whether the ophiolitic rocks and mélanges were (1) obducted onto the northern margin of India or (2) associated with the Cordilleran-style southern margin of Asia, prior to India - Asia collision. Resolving this issue is fundamental to understanding the precollisional tectonic framework of the Neo-Tethyan realm, interpreting the timing of initial continental collision from detrital records, and locating the suture. We conducted geologic mapping and U/Pb detrital zircon provenance studies of the blocks and matrix of the mélanges and of Tethyan Himalayan units to the south at two localities: near Lhatse, which is ~140 km north of Mt. Everest and near Lopu Kangri, ~300 km along strike to the west. Near Lhatse the mélange is composed of a mudstone matrix with blocks of basalt, chert, mudstone, metabasite, limestone, and sandstone. The majority of the blocks are deep-water facies or consistent with oceanic crust, supporting the interpretation that the mélange is an accretionary complex formed by oceanic subduction. A south-dipping fault ~9 km north of Lhatse separates the mélange to the north from a continuous sequence of sandstone, shale, and minor limestone to the south. Previous work along strike suggests that this sequence, which has been previously identified as Tethyan affinity, contains Asian affinity detrital zircon populations. Near Lopu Kangri, the mélange is similar to that exposed in Lhatse. Over a distance of ~10 km to the southwest, blocks gradually increase in size to encompass ~2 km x ~10 km areas of measurable section and the component of matrix gradually decreases. Eventually the matrix is absent and strain is apparently taken up in incompetent layers within the stratigraphic sections. U/Pb dating of detrital zircons suggest that the mélange contains Asian affinity blocks with young peak ages of ~130 Ma as well as Gondwanan affinity blocks with young peak ages of ~500-550 Ma. Sandstones from the matrix are interpreted as Asian affinity with young peak ages of ~125 Ma and maximum depositional ages of ~118 Ma. The coherent blocks of stratigraphy are of Gondwanan affinity and may represent part of a microterrane which entered the subduction system at ~120 Ma. Collectively, our preliminary results suggest the mélange matrix is of Asian affinity. This requires the ophiolitic rocks and mélanges to have been associated with the Cordilleran-style margin of Asia by ~120 Ma. In contrast, blocks of stratigraphic section in the mélanges are of Gondwanan affinity, and we interpret them to represent dismembered portions of a microterrane that accreted to the southern margin of Asia prior to India-Asia collision. Finally, our studies suggest that the suture between India and Asia is further south than previously recognized.

Metcalf, K.; Kapp, P. A.; Orme, D. A.; Laskowski, A. K.

2013-12-01

372

Deep electromagnetic soundings conducted in Trans-European Suture Zone  

Science.gov (United States)

A consortium of nine geophysical institutions recently carried out a large-scale geomagnetic experiment focused on revealing the deep electrical structure beneath central and eastern Europe around the Trans-European Suture Zone (TESZ), the region's first-order geological lineament. The TESZ is considered a broad zone of deformation that crosses all of Europe, from the British Isles in the northwest to the Black Sea area in the southeast, and it most likely continues in North America [Keller and Hatcher, 1999].The geomagnetic experiment was called Central Europe Mantle Geoelectrical Structure (CEMES). Initiated by Polish scientists, geophysicists from eight other countries joined the project during a NATO Advanced Research Workshop held in the spring of 2001 in Belsk, Poland. The experimental phase of the project was held from 2001 through 2002; and altogether, 12 geomagnetic observatories, the international codes of which are shown among others in Figure 1, took part in acquiring the data. They will serve the objective of inferring information on the mantle conductivity structures beneath the region of TESZ, as well as beneath surrounding units, specifically the western part of the East European Craton (EEC), Variscides, including the Bohemian Massif, the Carpathians, and the Pannonian Basin.

Semenov, Vladimir Yu.; Jozwiak, Waldemar; Pek, Josef

373

Bioinspired, mechanical, deterministic fractal model for hierarchical suture joints  

Science.gov (United States)

Many biological systems possess hierarchical and fractal-like interfaces and joint structures that bear and transmit loads, absorb energy, and accommodate growth, respiration, and/or locomotion. In this paper, an elastic deterministic fractal composite mechanical model was formulated to quantitatively investigate the role of structural hierarchy on the stiffness, strength, and failure of suture joints. From this model, it was revealed that the number of hierarchies (N) can be used to tailor and to amplify mechanical properties nonlinearly and with high sensitivity over a wide range of values (orders of magnitude) for a given volume and weight. Additionally, increasing hierarchy was found to result in mechanical interlocking of higher-order teeth, which creates additional load resistance capability, thereby preventing catastrophic failure in major teeth and providing flaw tolerance. Hence, this paper shows that the diversity of hierarchical and fractal-like interfaces and joints found in nature have definitive functional consequences and is an effective geometric-structural strategy to achieve different properties with limited material options in nature when other structural geometries and parameters are biologically challenging or inaccessible. This paper also indicates the use of hierarchy as a design strategy to increase design space and provides predictive capabilities to guide the mechanical design of synthetic flaw-tolerant bioinspired interfaces and joints.

Li, Yaning; Ortiz, Christine; Boyce, Mary C.

2012-03-01

374

A technique for the quantification of the 3D connectivity of thin articulations in bony sutures.  

Science.gov (United States)

The anatomy and development of cranial and facial sutures have been studied in detail using histological sections, 2D radiographs and more recently CT imaging. However, little attention has been paid to evaluating and quantifying the connectivity of these thin cortical bone articulations. More recent technological advances such as micro-CT imaging has the potential to be used to provide quantitative measurements of 3D connectivity in bony articulations. This study presents a new technique for quantifying the connectivity of bony projections inside cranial and facial sutures using a combination of skeletonization, thinning algorithms and 3D intensity mapping. The technique is demonstrated in five sutures through semi-automated analysis and image processing of microCT scans. In the sagittal, coronal and frontozygomatic sutures an average bone connectivity of 6.6-11.6% was found with multiple bony projections providing an interlocking structure between adjacent bones. Much higher bone connectivity was present in the zygomaticotemporal and zygomaticomaxillary sutures (22.7-37.4%) with few bony projections. This method combining microCT scanning and image processing techniques was successfully used to quantify the connectivity of thin bone articulations and allowed detailed assessment of sutural fusion in 3D. The wider application of this technique may allow quantification of connectivity in other structures, in particular fracture healing of long bones. PMID:20036366

Maloul, Asmaa; Fialkov, Jeffrey; Hojjat, Seyed-Parsa; Whyne, Cari M

2010-04-19

375

STUDY OF SKIN STAPLES AND CONVENTIONAL SUTURE FOR ABDOMINAL SKIN WOUND CLOSURE  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: The use of automatic stapling device for skin closure has become more popular due toits minimum disadvantages as compared to conventional suturing. Hence, this study was undertakento compare the time required for abdominal skin closure and pain during suture removal, between skinstaplers and conventional suture.Materials and Methods: The study includes 100 patients with age group of 45yrs-75yrs undergoingelective surgery, of which 50 patients underwent wound closure by staplers (Group-I and 50 patientsunderwent closure using prolene suturing (Group-II, during June 2009 to June 2011 at BasaweshwarTeaching and General Hospital, Gulbarga. Patients were randomly selected for conventional sutureand skin staple. Time duration for wound closure was recorded and pain scoring was given duringsuture removal, between both groups.Results and conclusion: In our study duration of wound closure was statistically significant(P<0.001 with staplers requiring lesser time than conventional prolene sutures, we also found thatpain during suture removal between both groups was statistically significant (P<0.001. We believethe advantages of speed and convenience of skin staples outweigh the extra cost, provided thedisposable instruments are reused until empty.

S. S. Karbhari

2012-07-01

376

Formability of Aluminum 5182-Polypropylene Sandwich Sheet for Automotive Application  

Science.gov (United States)

The AA5182/polypropylene/AA5182 (AA/PP/AA) sandwich sheet is the material fabricated by adhering two aluminum skins to one polypropylene core. When it has the same flexural rigidity as a steel sheet, it is 65% lighter than the steel sheet and 30% lighter than an aluminum alloy sheet. Therefore, it is notified exclusively as good substitutive materials for a steel body to improve the fuel efficiency. Through AA/PP/AA sandwich sheet, however, it has relatively lower formability than that of the steel sheet for automotive application. In this study, we developed formability evaluation techniques in order to apply AA/PP/AA sandwich sheet for an automotive parts. For this purpose, newly adopting formability evaluations (using limit dome height and plane strain test) were carried out in order to secure the fundamental data for the measurement of sheet metal forming and the establishment of optimum forming conditions of the sandwich sheet. The results showed that there were in good agreements between the old formability evaluation method and the new one which was more simplified than that of the old one. From the results of these formability evaluations, the formability of sandwich sheet was higher than that of aluminum alloy sheet alone which was the skin component for the sandwich sheet. In addition, it was found that sandwich sheet could reduce the weight and could have the same flexural rigidity simultaneously when it was compared to the automotive steel sheet.

Kim, Kee Joo; Kim, Cheol-Woong; Choi, Byung-Ik; Sung, Chang Won; Kim, Heon Young; Won, Si-Tae; Ryu, Ho-Yeun

377

Acoustic properties of polypropylene composites reinforced with stone groundwood  

Directory of Open Access Journals (Sweden)

Full Text Available Currently, acoustic isolation is one of the problems raised with building construction in Spain. The publication of the Basic Document for the protection against noise of the Technical Building Code has increased the demand of comfort for citizens. This has created the need to seek new composite materials that meet the new required acoustical building codes. In this paper we report the results of the newly developed composites that are able to improve the acoustic isolation of airborne noise. These composites were prepared from polypropylene (PP reinforced with mechanical pulp fibers from softwood (Pinus radiata. Mechanical and acoustical properties of the composites from mechanical pulp (MP and polypropylene (PP have been investigated and compared to fiberglass (FG composites. MP composites had lower tensile properties compared with FG composites, although these properties can be improved by incorporation of a coupling agent. The results of acoustical properties of MP composites were reported and compared with the conventional composites based on fiberglass and gypsum plasterboards. Finally, we suggest the application of MP composites as a light-weight building material to reduce acoustic transmitions.

Joan Pere López

2012-11-01

378

Morphology and properties of recycled polypropylene/bamboo fibers composites  

International Nuclear Information System (INIS)

Polypropylene (PP) is among the most widely used thermoplastics in many industrial fields. However, like other recycled polymers, its properties usually decrease after recycling process and sometimes are degraded to poor properties level for direct re-employment. The recycled products, in general, need to be reinforced to have competitive properties. Short bamboo fibers (BF) have been added in a recycled PP (RPP) with and without compatibilizer type maleic anhydride polypropylene (MAPP). Several properties of composite materials, such as helium gas permeability and mechanical properties before and after ageing in water, were examined. The effects of bamboo fiber content and fiber chemical treatment have been also investigated. We showed that the helium permeability increases if fiber content is higher than 30% because of a poor adhesion between untreated bamboo fiber and polymer matrix. The composites reinforced by acetylated bamboo fibers show better helium permeability due to grafting of acetyl groups onto cellulose fibers surface and thus improves compatibility between bamboo fibers and matrix, which has been shown by microscopic observations. Besides, mechanical properties of composite decrease with ageing in water but the effect is less pronounced with low bamboo fiber content.

379

Morphology and properties of recycled polypropylene/bamboo fibers composites  

Science.gov (United States)

Polypropylene (PP) is among the most widely used thermoplastics in many industrial fields. However, like other recycled polymers, its properties usually decrease after recycling process and sometimes are degraded to poor properties level for direct re-employment. The recycled products, in general, need to be reinforced to have competitive properties. Short bamboo fibers (BF) have been added in a recycled PP (RPP) with and without compatibilizer type maleic anhydride polypropylene (MAPP). Several properties of composite materials, such as helium gas permeability and mechanical properties before and after ageing in water, were examined. The effects of bamboo fiber content and fiber chemical treatment have been also investigated. We showed that the helium permeability increases if fiber content is higher than 30% because of a poor adhesion between untreated bamboo fiber and polymer matrix. The composites reinforced by acetylated bamboo fibers show better helium permeability due to grafting of acetyl groups onto cellulose fibers surface and thus improves compatibility between bamboo fibers and matrix, which has been shown by microscopic observations. Besides, mechanical properties of composite decrease with ageing in water but the effect is less pronounced with low bamboo fiber content.

Phuong, Nguyen Tri; chuong, Bui; Guinault, Alain; Sollogoub, Cyrille

2011-05-01

380

Preparation and Characterization of Coir, Luffa Reinforced Polypropylene Composites  

Directory of Open Access Journals (Sweden)

Full Text Available Natural fibres have been used to reinforce materials for over 3,000 years. More recently they have been employed in combination with plastics. Many types of natural fibres have been investigated for use in plastics including coir, luffa, flax, hemp, jute, sisal, and banana. Natural fibres have the advantages that they are renewable resources and have marketing appeal. These agricultural wastes can be used to prepare fibre reinforced polypropylene composites for commercial use. Application of composite materials to structures have presented the need for the engineering analysis this work focuses on the fabrication of polymer matrix composites by using natural fibres like coir, and luffa which are abundant nature in desired shapes by the help of various structures of patterns and calculating its material characteristics (tensile strength, flexural modulus, flexural rigidity, hardness number,% gain of water by conducting tests like tensile test, flexural test, hardness test, water absorption test, impact test, density test, sem analysis and their results are measured on sections of the material and make use of the natural fibre reinforced polypropylene composite material for automotive seat shell manufacturing.

S.Tharaknath

2014-10-01

381

Investigation of physical and chemical properties of polypropylene hybrid nanocomposites  

International Nuclear Information System (INIS)

Highlights: ? Effect of morphology and properties of PP hybrid nanocomposites was investigated. ? Intercalated-exfoliated structures were in the system. ? Significant improvement of physical and chemical properties in hybrid nanocomposites. ? PP hybrid nanocomposites showed good thermal stability. -- Abstract: Hybrid nanocomposites fabricated based on an optimized physical and chemical properties modified polypropylene (PP)/polypropylene grafted maleic anhydride (PP-g-MA) with varied concentrations (1-7 wt% at a step of 2 wt%) of organoclay, montmorillonite (MMT). The morphology of the nanocomposites was studied by scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). It was found that partly intercalated and partly exfoliated structure (intercalated-exfoliated structures) existed in the system. The degree of exfoliation is a key factor to determine the reinforcement efficiency. The ratio of exfoliation to intercalation plays an important role in determining the properties of PP nanocomposites and only completely exfoliated silicate layers can significantly improve the properties. PP hybrid nanocomposites showed good thermal stability in the thermogravimetric analysis (TGA). Introduction of ?3% MMT in the nanocomposites increased the onset temperature of degradation by 27.5 oC compared to that of pure PP, while the 5 wt% MMT resulted the maximum hardness in these nanocomposites. The solvent resistance of PP hybrid nanocomposites slightly increased with increasing the clay content.

382

The influence of antioxidant on positron annihilation in polypropylene  

International Nuclear Information System (INIS)

The purpose of this report is to check the influence of the carbonyl groups (CG), created by oxygen naturally dissolved in a polymer matrix and by the source irradiation, on annihilation characteristics of free positrons using the positron annihilation lifetime spectroscopy (PALS) and coincidence Doppler-broadening spectroscopy (CDBS). Positron annihilation in a pure polypropylene (PP) and in an antioxidant-containing polypropylene (PPA) sample at room and low temperatures has been studied by CDBS. PALS has been used as an o-Ps (orth-positronium) formation monitor. The momentum density distributions of electrons obtained by CDBS at the beginning of measurements have been compared to that at the o-Ps intensity saturation level. It has been shown that the initial concentration of carbonyl groups in a PP sample is high, while for an antioxidant-containing sample, PPA, carbonyl groups are not detected by CDBS. CDBS spectra for a PP can be explained by annihilation of free positrons with the oxygen contained in the carbonyl groups. For a PPA sample, no significant contribution of annihilation with oxygen core electrons can be concluded. (Y. Kazumata)

383

Effects of physical configuration and chemical structure of suture materials on bacterial adhesion. A possible link to wound infection.  

Science.gov (United States)

The purpose of this study was to examine the effects of physical configuration and the chemical nature of suture materials on the preferential adherence of bacteria. Ten suture materials of 2-0 (chromic catgut, Dexon, Vicryl, PDS, Mersilene, Tycron, Ethibond, Surgilon, Ethilon, and Prolene) were used. The bacterial strains tested were Staph. aureus and E. coli. The level of bacterial adherence was determined quantitatively by radiolabelled cells and qualitatively by scanning electron microscopy. It was found that the amount of adhered bacteria depended on the type of suture material, the type of bacteria, and the duration of contact. In the group of absorbable sutures, the new PDS sutures exhibited the smallest affinity toward the adherence of both E. coli and Staph. aureus. Dexon sutures had the highest affinity toward these two bacteria. With nonabsorbable sutures, the physical configuration of the sutures contributed more to their ability to attract bacteria than the surface finish. The bacterial adherence on suture materials was also time dependent. Scanning electron microscope morphologic observation also indicated that Staph. aureus adhered on the suture surface in clusters whereas E. coli tended to adhere individually. PMID:6364858

Chu, C C; Williams, D F

1984-02-01

384

Investigation of the nanostructure and mechanical properties of polypropylene/polyamide 6/layered silicate ternary nanocomposites  

International Nuclear Information System (INIS)

This work aims to investigate the structure-property relationship in ternary nanocomposites consisting of polypropylene as the matrix, nanoclay as the reinforcement and polyamide 6 as the intermediate phase. In this regard, composites of polypropylene/organoclay, polyamide/organoclay, blends of polypropylene/polyamide, and ternary nanocomposites of polypropylene/polyamide/layered silicate with and without compatibilizer were produced via melt compounding. Nanostructure was investigated by wide-angle X-ray diffraction and transmission electron microscopy. Scanning electron microscopy was employed to study the microstructure. Modulus of elasticity and yield strength were measured by uniaxial tensile test. Results show that silicate layers can only be observed inside polyamide particles. Moreover, polypropylene was unable to intercalate the grade of organoclay used in this study. While polyamide/organoclay system exhibited an exfoliated structure, the nanostructure of ternary nanocomposites was chiefly intercalated, due to the high concentration of silicate layers inside polyamide particles. Incorporation of organoclay into the polypropylene/polyamide system was seen to have a noticeable effect on the shape and size of polyamide particles. In addition, elastic modulus and yield strength were observed to be directly affected by incorporation of nanoclay and compatibilizer into the polypropylene matrix, respectively. The simultaneous presence of the two constituents in the system resulted in samples with superior mechanical properties in the elastic as well as the plastic deformation regime.

385

TENSILE STRENGTH CHARACTERISTICS OF POLYPROPYLENE COMPOSITES REINFORCED WITH STONE GROUNDWOOD FIBERS FROM SOFTWOOD  

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Full Text Available The behavior of stone groundwood / polypropylene injection-molded composites was evaluated with and without coupling agent. Stone groundwood (SGW is a fibrous material commonly prepared in a high yield process and mainly used for papermaking applications. In this work, the use of SGW fibers was explored as a reinforcing element of polypropylene (PP composites. The surface charge density of the composite components was evaluated, as well as the fiber’s length and diameter inside the composite material. Two mixing extrusion processes were evaluated, and the use of a kinetic mixer, instead of an internal mixer, resulted in longer mean fiber lengths of the reinforcing fibers. On the other hand, the accessibility of surface hydroxyl groups of stone groundwood fibers was improved by treating the fibers with 5% of sodium hydroxide, resulting in a noticeable increase of the tensile strength of the composites, for a similar percentage of coupling agent. A new parameter called Fiber Tensile Strength Factor is defined and used as a baseline for the comparison of the properties of the different composite materials. Finally the competitiveness of stone groundwood / polypropylene / polypropylene-co-maleic anhydride system, which compared favorably to sized glass-fiber / polypropylene GF/PP and glass-fiber / polypropylene / polypropylene-co-maleic anhydride composite formulations, was quantified by means of the fiber tensile strength factor.

Joan P. López,

2012-06-01

386

Study of polypropylene/polybutene blends modified by gamma irradiation and (high melt strength polypropylene)/polybutene blends  

International Nuclear Information System (INIS)

It is well-known that polypropylene (PP) is difficult to process as a consequence of its linear structure. It is also known that grafting of long-chain branches on PP backbone using ionizing radiation is an effective approach to achieve high melt strength polypropylene (HMS PP). Chain-scission and, in minor extend, crosslinking and grafting are the predominant reaction in order to branch PP backbone. However, if multifunctional monomers are used to promote the grafting reaction, crosslinking can surpass chain scission and grafting, reducing drawability. Therefore, in an effort to enhance the processability and so the drawability, it has been found helpful to add a small amount of polybutene-1. Gamma irradiation technique was used to induce chemical changes in blends of PP and polybutene in acetylene atmosphere (crosslinker promoter) and in HMSPP/polybutene blends. The samples were irradiated with a 60Co source with doses of 12.5 and 20 kGy in the presence of acetylene. In this work, two different methods of blends processing were compared regarding rheological and mechanical properties. Effects on the strength and elongation at the yield point and at rupture were observed by mechanical tests and showed decrease of tensile strength and increase of elongation at rupture for samples obtained by irradiation of blends. The results from rheology demonstrated an increase in melt strength and drawability of blends

387

Comparison of rheological and mechanical properties of modified polypropylene - short glass fiber composites  

International Nuclear Information System (INIS)

Short glass fiber (SGF) reinforced composite materials were principally fabricated using polypropylene (PP) as thermo-plastic matrix. Short glass fiber and polypropylene frequently suffer from lack of adequate fiber-matrix adhesion. This problem was addressed by grafting polypropylene (PP) with maleic anhydride (MA) in the presence of benzyl peroxide (BPO) as an initiator. The results revealed that by increasing fiber contents from 5 to 40 %, tensile strength increases while elongation at break decreases. Rheological behavior was found to be pseudoplastic, whereas viscosity increases by increasing SGF contents. A decrease in die swell was observed with increase in SGF contents. (author)

388

Development of polypropylene/wood flour ecocomposites. Evaluation of silane as coupling agent  

International Nuclear Information System (INIS)

The effects of Pinus Sylvestris wood flour as filler in polypropylene matrix was evaluated. The mechanical properties and the morphology of different wood flour/polypropylene composites (WPC) were studied. The composites materials were prepared with several amounts of wood flour from 10 to 30% wt. Mechanical properties show that the wood flour incorporation increases the rigidity of the composites. Morphological analysis indicates that agglomerates are formed, with amounts exceeding 30% of wood flour. For the silane--treated composites, the dispersion of the filler into the polypropylene (PP) matrix improved. Shore D hardness of the composites is decreased with the addition of the coupling agent.

389

Pulse NMR-spectroscopy of structural changes of chemically modified polypropylene  

International Nuclear Information System (INIS)

The structure of polypropylene compositions is studied by the method of pulse NMR-spectroscopy. The polypropylene compositions are derived by means of the modification by multicomponent systems. The analysis of relaxation times in a wide temperature range is carried out. Character of changes going on at a level of supermolecular structures is described. It is shown that the amplifications that manifest themselves under the polypropylene modification by the mixtures based on 2,4-tolyilendiisocyanate and e-caprolactam, are related to the change in the intermolecular interaction and formation of a more ordered polymer structure. (authors)

390

Técnica de suturas ajustables: Resultados Technique of adjustable sutures: Results  

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Full Text Available Se realizó un estudio sensorial y motor preoperatorio y posoperatorio a 84 pacientes que acudieron a la consulta de Visión Binocular con el diagnóstico de estrabismo horizontal a partir de los 13 años de edad. El método estadístico utilizado fue "t" o Chi cuadrado. Nos trazamos como objetivo determinar los resultados posoperatorios de la cirugía de estrabismo realizada con la técnica de suturas ajustables, que fueron los siguientes: el 61 % de los pacientes con exotropía y el 71,4 % con el diagnóstico de exotropía se encontraban en ortotropía a los 6 meses de la intervención. El 71,4 % de los pacientes con esotropía y el 83,3 % con el diagnóstico de esotropía se encontraban en ortotropía al año de la intervención. Esta técnica quirúrgica permite la modificación de la desviación en el posoperatorio inmediato.A preoperative and postoperative sensorial and motor study was conducted among 84 patients who received attention at the consultation room of Binocular Vision with the diagnosis of horizontal strabismus from the age of 13 years old on. The statistical method used was "t" or chi square test. Our objective was to determine the postoperative results of the strabismus surgery performed by the technique of adjustable sutures. The results were as follows: 61 % of the patients with exotropia and 71.4 % with the diagnosis of exotropia were in orthotropia 6 months after the operation. 71.4 % of the patients with exotropia and 83.3 % with the diagnosis of exotropia were in orthotropia a year after the operation. This surgical technique allows the modification of the deviation in the immediate postoperative.

Lourdes R. Hernández Santos

2001-06-01

391

Proterozoic Farwell Mountain Lester Mountain suture zone, northern Colorado: Subduction flip and progressive assembly of arcs  

Science.gov (United States)

This paper considers the amalgamation of arc and oceanic terranes to be the main mechanism of ca. 1.8 1.6 Ga continental crustal growth in southwestern Laurentia. On the basis of geologic and seismic reflection data and teleseismic images, we propose the Farwell Mountain Lester Mountain suture zone as the northernmost Paleoproterozoic arc-arc suture. North-dipping (Farwell Mountain) seismic reflections project from 18 km depths to the surface and are interpreted to represent conjugate thrusting as the 1.79 1.77 Ga Green Mountain arc was partially underthrust beneath the Archean craton. We speculate that a north-dipping high-velocity mantle “slab” in the teleseismic image is a continuation of this thrust zone. South-dipping (Lester Mountain) reflections project from 22 km depths to the surface and are interpreted to be a thrust zone between the Green Mountain arc and the 1.76 1.72 Ga Rawah block. Surface features of the Farwell Mountain Lester Mountain suture zone are (1) marble, chert, rock with sillimanite pods, ultramafic rocks, sulfide deposits, and pillow basalts, which we interpret to be a dismembered accretionary complex; (2) an axial-planar fabric to north-verging isoclinal folds (F2), which we interpret to be part of a north-vergent fold-and-thrust system; and (3) a metamorphic break between ˜500 °C rocks to the north and ˜610 °C rocks to the south, which we attribute to reactivation of the zone. Movement on the Farwell Mountain backthrust is inferred to relate to Cheyenne belt suturing at 1.78 1.75 Ga. We correlate suturing in the Farwell Mountain Lester Mountain suture zone to S1/D1 (1.746 1.74 Ga) in the Soda Creek Fish Creek shear zone. We attribute the complexity of this broad suture zone to initial conjugate thrusting, plus overprinting and steepening of accretionary structures by subsequent tectonism.

Tyson, A. R.; Morozova, E. A.; Karlstrom, K. E.; Dueker, K. R. Chamberlain S. B. Smithson K. G.; Foster, C. T.

2002-10-01

392

Comparison of CO2 laser welding with suture technique for repair of tendons  

Science.gov (United States)

The purpose of this study was to evaluate the efficacy, histology, and strength of laser welding in repair of sharply transected rat Achilles tendons. In 26 adult, male Sprague-Dawley rats, the severed tendons were repaired with a 7-0 nylon, modified Kessler core suture followed by either a running 9-0 nylon epitendinous suture or a circumferential CO2 laser epidendinous weld using 25% human albumin as a solder. All repairs were timed and post- operative tensile strength was analyzed with material testing equipment. In addition, histologic testing was performed on both types of repairs. The mean time to complete the epitendinous repair in the laser group was 3.5 minutes and in the suture group, 8 minutes. The mean ultimate tensile strength in 6 normal tendons was 40.9 Newtons (N) with group standard deviation of 5.2 N. When compared with normal controls, post-operatively both types of tendon repairs resulted in tensile failure at lower forces. The ultimate tensile strength for the epitendinous suture repair and the laser welds were 13% and 6% of normal controls, respectively. Twenty tendons with epidendinous suture repair had mean ultimate tensile strength of 5.4 (+/- 1.2) N, while the 17 tendons with laser wends failed at 2.6 (+/- 0.9) N. Histologic evaluation of tendons repaired with CO2 laser revealed areas of coagulation and edema on the surface of tendon edges. Post-operatively, greater tissue changes were noted in laser treated tendons than those repaired with sutures. Laser welding of epitenon is possible and can be completed faster than the suture repair. The repaired tendon surface appears smoother and less bulky after laser treatment. However, significantly decreased immediate post-operative strength was demonstrated by the use of Kruskal-Wallis one way analysis of variance and Turkey's pairwise comparison.

Popovic, Neven A.; Johnstone, Frederic L.; Kilkelly, Francis X.; McKinney, LuAnn; Van De Merwe, Willem P.; Smith, Allan C.

1995-05-01

393

Inflammatory reaction and tensile strength of the abdominal wall after an implant of polypropylene mesh and polypropylene/poliglecaprone mesh for abdominal wall defect treatment in rats  

Scientific Electronic Library Online (English)

Full Text Available PURPOSE: To compare the inflammatory reaction and the growing resistance of the abdominal wall with the use of poliglecaprone meshes and polypropylene meshes associated with poliglecaprone in the correction of abdominal defects. METHODS: Seventy-seven Wistar rats were divided into three groups [...] : CG (non-operated animals: EG (polypropylene mesh) and UG (polypropylene and poliglecaprone mesh). A muscular and aponeurotic defect was formed and treated according to the group. Evaluations were made after 4, 7, 14, 28 and 56 days. The resistance and inflammatory pattern were studied. RESULTS: There was a gradual and significant gain in resistance, regularly in the EG and irregularly in the UG, which was lower on the 14th day (p=0.008). The inflammatory reaction was acute and more intense in the UG on the fourth day. At all other times, the inflammatory pattern was acute to chronic, similar in both groups, with minimum intensity on the 56th day. CONCLUSION: The greater resistance offered by the polypropylene mesh was regular and ascending, stabilizing on the 28th day, while that of the polypropylene/poliglecaprone was not even. In the end, the resistances were similar. The inflammatory response was greater in the UG on the fourth day and similar at all other times.

Maria de Lourdes Pessole, Biondo-Simões; Paula Almeida Pamponet, Moura; Kelly, Colla; Anna Flávia Zonato, Tocchio; Camila Gomes de, Morais; Renata Augusta de, Miranda; Rogério Ribeiro, Robes; Sérgio Ossamu, Ioshii.

394

Reinforcing effect of nanosilica on polypropylene-nylon fibre composite  

International Nuclear Information System (INIS)

Polymer composites reinforced by both the micro and nano fillers is the subject of this paper. Polypropylene (PP)-nylon micro-fibre composites modified with nanosilica and modified nanosilica (using silane coupling agent) were prepared by melt compounding. The nanosilica prepared in the laboratory was used as reinforcing filler in PP-nylon fibre composites. The compounding characteristics and mechanical properties of the composites were studied. The equilibrium torque during compounding increased with the addition of nanosilica and modified nanosilica. The use of two types of fillers leads to synergistic effect on the mechanical properties of the composite. Composites with 1 wt.% nanosilica and 30 wt.% nylon fibre show high tensile strength, tensile modulus, flexural strength and flexural modulus. Composites modified with 1 wt.% nanosilica and 10 wt.% nylon fibre-PP composite show higher impact strength.

395

Raman Spectra and Mechanical Properties of Graphene/Polypropylene Nanocomposites  

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Full Text Available Graphene/Polypropylene nanocomposites were prepared at different filler loading and different average surface diameter 5, 15 and 25?m of graphene nanoplatelets by using Haake Minilab mixer at 180oC and rotor speed 50rpm. Besides, Haake MiniJet is used to obtain dumbbell shape specimen. The effect of filler loading and average surface area of filler in PP/GnP composites on Raman spectrum and tensile properties were studied. Raman spectrum of graphene particles indicate three major spectrums such as D, G and 2D band. In addition, PP/GnP composites shows the Raman band shift quite strong by increasing GnP loading. In general, increased of graphene nanoplatelets loading have increased the value of modulus of elasticity, whereas tensile strength, elongation at break of composites reduced

Siti R. Ahmad

2015-02-01

396

Characterization of electron-irradiated biaxially-oriented polypropylene films  

International Nuclear Information System (INIS)

Post-radiation changes in the electrical and mechanical properties of capacitor-grade isotactic polypropylene films exposed to electron radiation were reported in a previous paper. Based on the data obtained, it was suggested that crosslinking, chain scission and oxidative degradation were responsible for the radiation-induced changes in the film. In the present investigations, additional electrical characterizations that included the dc breakdown voltage and ac conductivity measurements were performed. Effects of the electron radiation on the physical and chemical properties were also evaluated so as to identify the actual degradation mechanisms. These studies included scanning electron microscopy, X-ray diffraction, infrared spectroscopy and sol gel measurements. The results obtained confirm that crosslinking and chain scission of the polymer are responsible for the changes in the lower dose range, whereas oxidative degradation become predominant at higher dose levels

397

Radiation grafting of maleic anhydride onto polypropylene in suspension system  

Science.gov (United States)

This paper studies the grafting of maleic anhydride (MAH) onto polypropylene (PP) performed in suspension through co-irradiation in the absence of an initiator. The effect of radiation dose and MAH concentration on the graft degree of MAH onto PP was investigated. The graft degree and relative viscosity of grafted MAH were investigated by means of chemical titration and viscosity measurements. The results show that the co-irradiation in suspension systems can obviously cause the increase of the amount of grafted MAH, implying that the grafting reaction consists of chain scission and the grafting reaction of the produced macroradicals with MAH. The percentage of grafting of the product amounts to 4.82%. The molecular structures of the prepared grafted MAH were characterized by Fourier-transform infrared spectroscopy (FT-IR). Differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WXRD) were used to determine the degree of crystallinity and crystalline structure.

Tan, Xiumin; Xu, Yongshen

398

Radiation resistance of polyolefins and their composites. Pt. 1. Polypropylene  

International Nuclear Information System (INIS)

The gel permeation chromatography, MFR, and ESR techniques were used to study the resistance to radiation, via molecular weight and viscosity determinations, in homopolymeric PP (Malten PJ 601 and PP 401), a propylene/ ethylene copolymer (Malten PJ 330) and PP modified with propylene/ethylene and ethylene/vinyl acetate copolymers (PP Mod MKE 93) each prepared at the INCT, Warsaw. The MKE 93 and Malten PJ 330 were found to be most resistant to fast electrons. Irradiation results in the degradation and simultaneous reduction of poly disparity in the PP examined MFR measurements and GPC gave consistent results. The higher the polypropylene molecular weight, the greater degree of degradation induced. The MKE 93, i.e., PP most resistant to radiation proved suitable for production of radiation-sterilized hypodermic syringes. (author). 15 refs, 6 tabs, 1 fig

399

Noncontact ultrasonic spectroscopy applied to the study of polypropylene ferroelectrets  

Science.gov (United States)

Noncontact ultrasonic spectroscopy (NCUS) is used to excite and sense thickness resonances in films of polypropylene ferroelectrets. From the comparison of these measurements with theoretical calculations it is possible to extract some material properties: film thickness and density, velocity, and attenuation of ultrasounds and variation in these two magnitudes with the frequency. Hence elastic compliance and acoustic impedance are worked out. Observed variation in the attenuation with the frequency exhibits classical viscoelastic behavior which can be used to investigate the underlaying physical mechanism. In addition, the influence of the metallization on the film response is studied. A modification of the NCUS method is proposed on the basis of the piezoelectric response of these films, which give rise to an alternative characterization method. Consistency of both methods is verified.

Gómez Álvarez-Arenas, T. E.; Calás, H.; Cuello, J. Ealo; Fernández, A. Ramos; Muñoz, M.

2010-10-01

400

Aqueous Processes for Dyeing Generic, Unmodified Polypropylene Fiber  

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Full Text Available Acid leuco vat dyeings of polypropylene (PP fabrics in combinations of a trichromatic series of colorants (red, yellow and blue plus an orange were performed in order to determine the compatibility of the component colorants in the developed single stage, batch exhaust dyeing process reported earlier. Cross-section micrographs of dyed fibers revealed the absence of "ring-dyeing". Tensile tests and X-ray crystallinity results confirmed that the developed dyeing process did not significantly alter the tensile strength and modulus of the dyed PP textiles. PP fabrics dyed with simulated, continuous acid vat dyeing processes (pad-steam and pad-dry heat demonstrated good color yields and levelness with adequate fastness to crocking, washing and dry cleaning.

Murari L. Gupta

2010-06-01

401

Characterization of Fibers Produced from Blends of Polybutylene and Polypropylene  

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Full Text Available Blends of polybutylene (PB-1 and polypropylene were used to produce fibers at spinning speeds of 800-2100 m/min. Concentrations ranged from 0% PP to 100% PP. The stress-strain behavior of the resultant fibers was examined, and the fibers were analyzed for crystallinity via DSC (differential scanning calorimetry. Fibers produced from blends of PB-1/PP show mechanical properties that are in between the properties of the pure polymers. The tensile strength of 50% PB-1 fibers is comparable to the tensile strength of pure PP fibers. Fibers produced from blend compositions of 25 and 75% have higher tensile strengths than pure PP fibers, although these blend compositions have lower tensile strengths than pure PB fibers.

Robert L. Shambaugh, Ph.D

2007-11-01

402

Characterization of Grafted Polypropylene-Acrylamide Films for Dye Removal  

International Nuclear Information System (INIS)

The graft copolymerization of Acrylamide onto polypropylene film using the direct gamma irradiation technique was studied. The factors affecting the grafting process such as type of solvent, inhibitor, radiation dose, and monomer concentration on the grafting yield were studied. It was found that the additions of 0.5 wt % , Mohr's salt reduced effectively the homo polymerization of acrylamide. The change in chemical structural of the pp-films due to grafting was investigated using IR, X-ray diffraction, thermal gravimeterical analysis, and scanning electron microscope (SEM). PP-g-p(AAm) films were allowed to react with two ionic dyes; organic reactive blue dye (Remazol Brilliant Bright Blue) and organic reactive red dye (Drimarene Scarlet K-2 G). The sshas been analyzed with visible spectrophotometry at 460 nm for dyed grafted film by red dye and at 490 nm for dyed grafted film by blue dye

403

Surface treated polypropylene (PP) fibres for reinforced concrete  

Energy Technology Data Exchange (ETDEWEB)

Surface treatments on a polypropylene (PP) fibre have contributed to the improvement of fibre/concrete adhesion in fibre-reinforced concrete. The treatments to the PP fibre were characterized by contact angle measurements, ATR-IR and XPS to analyse chemical alterations. The surface topography and fibre/concrete interaction were analysed by several microscopic techniques, namely optical petrographic, and scanning electron microscopy. Treatment modified the surface chemistry and topography of the fibre by introducing sodium moieties and created additional fibre surface roughness. Modifications in the fibre surface led to an increase in the adhesion properties between the treated fibres and concrete and an improvement in the mechanical properties of the fibre-reinforced concrete composite as compared to the concrete containing untreated PP fibres. Compatibility with the concrete and increased roughness and mineral surface was also improved by nucleated portlandite and ettringite mineral association anchored on the alkaline PP fibre surface, which is induced during treatment.

López-Buendía, Angel M., E-mail: buendia@uv.es [AIDICO Technological Institute of Construction, Benjamin Franklin 17, 46380 Paterna, Valencia (Spain); Romero-Sánchez, María Dolores [AIDICO Technological Institute of Construction, Marble Technical Unit, Camí de Castella 4, 03660 Novelda. Alicante (Spain); Climent, Verónica [Lafarge Cementos, Polígono Sepes, Isaac Newton s/n, 46500 Sagunto, Valencia (Spain); Guillem, Celia [AIDICO Technological Institute of Construction, Marble Technical Unit, Camí de Castella 4, 03660 Novelda. Alicante (Spain)

2013-12-15

404

Effects of the Biodegradation on Biodegradable Polymer Blends and Polypropylene  

Science.gov (United States)

The large use of plastics in the world generates a large amount of waste which persists around 200 years in the environment. To minimize this effect is important to search some new polymer materials: the blends of biodegradable polymers with synthetic polymers. It is a large area that needs an intensive research to investigate the blends properties and its behavior face to the different treatments to aim at the biodegradation. The blends used in this work are: some biodegradable polymers such as: poly(hydroxybutyrate) (PHB) and poly(?-polycaprolactone) (PCL) with a synthetic polymer, polypropylene (PP), in lower concentration. These blends were prepared using an internal mixer (Torque Rheometer), and pressed. These films were submitted to fungus biotreatment. The films analyses will be carried out by Fourier Transform Infrared (FTIR), UV-Vis absorption (UV-Vis), Scanning Electronic Microscopy (SEM), DSC and TGA.

Pereira, R. C. T.; Franchetti, S. M. M.; Agnelli, J. A. M.; Mattoso, L. H. C.

2008-08-01

405

Effect of polybutenes on mechanical and physical properties of polypropylene  

International Nuclear Information System (INIS)

This study investigated the effect of polybutene (PIB) of molecular weights ranging from 480 the 1.600 g/mol in polypropylene homopolymer. Compositions with 0, 3, 5 and 7% of PIB were prepared in internal mixer and compression moulded. The properties evaluated were: tensile strength, scanning electron microscopy (SEM), FTIR, X-ray diffraction (XRD) and melt flow index (IF). The results of mechanical tests showed that the presence of the plasticizer reduced the tensile strength, elastic modulus and hardness. The analysis of XRD showed a drop in the degree of crystallinity of PP/PIB blends. The micrographs obtained by SEM did not reveal the occurrence of the phase separation. The IF analysis confirm the effect of PIB as internal lubricant's, by increasing the rate of flow. (author)

406

High-Strength Welds in Metallocene Polypropylene/Polyethylene Laminates  

Science.gov (United States)

Spectacular advances in organometallic chemistry over the past two decades have resulted in single-site catalysts that are revolutionizing production of polyethylene (PE) and isotactic polypropylene (iPP). This report describes an unanticipated benefit of metallocene-catalyzed semicrystalline polyolefins, namely welded joint strengths in PE/iPP laminates that can exceed the cohesive strength of the constituents. We propose that interfacial polymer entanglements, established in the molten state and subsequently anchored in chain-folded lamellae upon crystallization, are responsible for this intrinsic property. The poor adhesion exhibited by traditional Ziegler-Natta-catalyzed polyolefins is shown to derive from the accumulation of amorphous polymer, a by-product of the polymerization reactions, at the interface. These results should facilitate fabrication and improve the properties of composites based on materials that dominate the plastics industry.

Chaffin, Kimberly A.; Knutsen, Jeffrey S.; Brant, Patrick; Bates, Frank S.

2000-06-01

407

Surface treated polypropylene (PP) fibres for reinforced concrete  

International Nuclear Information System (INIS)

Surface treatments on a polypropylene (PP) fibre have contributed to the improvement of fibre/concrete adhesion in fibre-reinforced concrete. The treatments to the PP fibre were characterized by contact angle measurements, ATR-IR and XPS to analyse chemical alterations. The surface topography and fibre/concrete interaction were analysed by several microscopic techniques, namely optical petrographic, and scanning electron microscopy. Treatment modified the surface chemistry and topography of the fibre by introducing sodium moieties and created additional fibre surface roughness. Modifications in the fibre surface led to an increase in the adhesion properties between the treated fibres and concrete and an improvement in the mechanical properties of the fibre-reinforced concrete composite as compared to the concrete containing untreated PP fibres. Compatibility with the concrete and increased roughness and mineral surface was also improved by nucleated portlandite and ettringite mineral association anchored on the alkaline PP fibre surface, which is induced during treatment

408

Thermal degradation and viscoelasticity of polypropylene-clay nanocomposites  

CERN Document Server

Results of torsional oscillation tests are reported that were performed at the temperature T=230C on melts of a hybrid nanocomposite consisting of isotactic polypropylene reinforced with 5 wt.% of montmorillonite clay. Prior to mechanical testing, specimens were annealed at temperatures ranging from 250 to 310C for various amounts of time (from 15 to 420 min). Thermal treatment induced degradation of the matrix and a pronounced decrease in its molecular weight. An integro-differential equation is derived for the evolution of molecular weight based on the fragmentation-aggregation concept. This relation involves two adjustable parameters that are found by fitting observations. With reference to the theory of transient networks, constitutive equations are developed for the viscoelastic response of nanocomposite melts. The stress-strain relations are characterized by three material constants (the shear modulus, the average energy for rearrangement of strands and the standard deviation of activation energies) tha...

Drozdov, A D; Drozdov, D A; Gupta, R K

2003-01-01

409

Broad line NMR study of modified polypropylene fibres  

International Nuclear Information System (INIS)

Study of drawn fibres prepared from an isostatic polypropylene modified by an ethylene aminoalkylacrylate copolymer has been done using the broad line of 1H NMR. NMR spectra were measured on the set of fibres prepared with a draw ratio ? from 1 to 5.5 at two temperatures, one of them corresponding to the onset of segmental motion and the other one is the minddle of the temperature interval as determined by decrease of the second moment M2. Decomposition of the spectra into elementary components related to the amorphous, intermediate and crystalline regions of partially crystalline polymers has been made. The drawing of the fibres was found to enhance the chain mobility in the amorphous region and to restrain the molecular motion in the intermediate region. Such behaviour well supports conclusions predicted in the earlier study based on the spin-lattice relaxation time T1 and dynamic mechanical data treated using the WLF theory. (Authors)

410

Refractive index of corona-treated polypropylene films  

Science.gov (United States)

The samples under investigation are 20 µm thick isotactic polypropylene films corona treated at different corona polarities and grid voltages in a three-electrode system. In order to control the results of the applied treatment a combination of two refractive index (RI) measuring techniques (laser refractometry and spectrophotometry) is used to study RI dispersion in the spectral range 400-1000 nm. It is found that the surface RI was lower than the volume RI. After a corona treatment both surface and volume RI increase. The changes of the volume RI as compared to surface values are more influenced by the corona treatment conditions: the greater the grid potential, the bigger the volume RI.

Yovcheva, T.; Babeva, Tz; Nikolova, K.; Mekishev, G.

2008-05-01

411

Packing parameters effect on injection molding of polypropylene nanostructured surfaces  

DEFF Research Database (Denmark)

In today´s industry, applications involving surface patterning of sub-?m to nanometer scale structures have shown a high growth potential. To investigate the injection molding capability of replicating sub-?m surface texture on a large scale area, a 30x80 mm2 tool insert with surface structures having a diameter of 500 nm was employed. The tool insert surface was produced using chemical-based-batch techniques such aluminum anodization and nickel electroplating. During the injection molding process, polypropylene (PP) was employed as material and packing phase parameters (packing time, packing pressure) were investigated. The replicated surface topographies were quantitatively characterized by atomic force microscopy using specific three-dimensional surface parameters and qualitatively inspected by scanning electron microscopy. Results showed that the degree of replication from the tool to the polymer part was mainly influenced by packing pressure level and distance from the gate.

Calaon, Matteo; Tosello, Guido

2012-01-01

412

Effect of Natural Fiber Reinforced Polypropylene Composite Using Resin Impregnation  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, we deals with mechanical performance of resin impregnation with natural fiber and fiber reinforced composites. The effect of the addition of a rein impregnation process on static strength of the injection molded composites was investigated by carrying out tensile and banding tests, followed by Scanning electron microscopy (SEM observation of fiber surface and fracture surface of composites. The tensile strength of natural fiber and natural fiber reinforced composites with resin impregnation method increases with Polyvinyl alcohol (PVA impregnation. In addition, Phenol resin impregnation recovers fiber tensile strength after alkali treatment. Resin impregnation causes decrease in contact surface area; however, it does not cause decrease in mechanical properties. Our results suggest that the using rein impregnation method has better effect on the mechanical properties of natural fiber reinforced Polypropylene (PP composites.

Gibeop Nam

2014-11-01

413

The Performance of Barium Sulfate Nanoparticles/polypropylene Hybrid Multifilament  

Science.gov (United States)

Nanosize barium sulfate (BaSO4) particles prepared with dodecyl benzene sulfonic acid (DBSA) in ethanol-water reaction system are used to prepare BaSO4/polypropylene (PP) nanocomposites by melt mixing method. It is then made into hybrid fibers by melt spinning and subsequent drawing with different ratios. The hybrid fibers are characterized by rheology, morphology, thermal stability and mechanical properties, respectively. The results indicate that the DBSA-modified BaSO4 can improve the spinnability of BaSO4/PP hybrid multifilament even at high BaSO4 nanoparticles concentration. DBSA can be used as compatibilizer to enhance the interface interaction of BaSO4/PP nanocomposites, because DBSA contains both hydrophobicity long alkyl chain and hydrophilic sulfonic group. Therefore, it can improve the performances of BaSO4/PP hybrid multifilament.

Li, Ying; Wang, Xuanjun; Mu, Xiaoxi; Zhang, Shujuan

2012-01-01

414

Reinforcing effect of nanosilica on polypropylene-nylon fibre composite  

Energy Technology Data Exchange (ETDEWEB)

Polymer composites reinforced by both the micro and nano fillers is the subject of this paper. Polypropylene (PP)-nylon micro-fibre composites modified with nanosilica and modified nanosilica (using silane coupling agent) were prepared by melt compounding. The nanosilica prepared in the laboratory was used as reinforcing filler in PP-nylon fibre composites. The compounding characteristics and mechanical properties of the composites were studied. The equilibrium torque during compounding increased with the addition of nanosilica and modified nanosilica. The use of two types of fillers leads to synergistic effect on the mechanical properties of the composite. Composites with 1 wt.% nanosilica and 30 wt.% nylon fibre show high tensile strength, tensile modulus, flexural strength and flexural modulus. Composites modified with 1 wt.% nanosilica and 10 wt.% nylon fibre-PP composite show higher impact strength.

Jacob, Sinto [Department of Polymer Science and Rubber Technology, Cochin University of Science and Technology, Kochi-22, Kerala (India); Suma, K.K. [Department of Polymer Science and Rubber Technology, Cochin University of Science and Technology, Kochi-22, Kerala (India); Department of Chemistry, Maharaja' s college, Ernakulam, Kerala (India); Mendez, Jude Martin [Department of Polymer Science and Rubber Technology, Cochin University of Science and Technology, Kochi-22, Kerala (India); Department of Chemistry, St. Alberts college, Ernakulam, Kerala (India); George, K.E., E-mail: kegeorge@cusat.ac.i [Department of Polymer Science and Rubber Technology, Cochin University of Science and Technology, Kochi-22, Kerala (India)

2010-04-15

415

High energy irradiation effects on thermal stability of isotactic polypropylene  

International Nuclear Information System (INIS)

Polyolefins show good resistance to energy transfer from incident high energy particles. The presence of antioxidants causes an advanced crosslinking by blocking oxidative degradation, and a remarkable chemical resistance to oxidative degradation. These experiments, performed on i-polypropylene in the presence of Irganox 1076 or Topanol OC as shelf stabilizers, were carried out by means of oxygen uptake method under isothermal (165 deg.C) and isobaric (normal pressure) conditions. Oxidation investigations were performed in air as degradation environment. Additive concentration was 0.25 % (w/w). Three ?-exposure doses (50, 100 and 150 kGy) were selected. The influence of radiation treatment on the efficiency of studied compounds was shown. (authors)

416

Crystallization and melting of biodegradable poly(propylene suberate)  

International Nuclear Information System (INIS)

Highlights: ? Thermal behavior of biodegradable polyester poly(propylene suberate) is discussed. ? Tmo and ?Hmo were found 79.7 oC and 28.9 kJ/mol, respectively. ? Banded spherulitic morphology was observed. ? Crystallization regime II to III transition appears at 40 oC. ? Interestingly Ozawa model for non-isothermal crystallization fits experimental data. - Abstract: Thermal behavior of poly(propylene suberate) (PPSub) was studied. PPSub is a novel biodegradable polyester which always shows lower crystallinity, and thus faster biodegradation, than poly(?-caprolactone) or poly(butylene succinate). Crystalline structure, multiple melting behavior and re-crystallization of PPSub on heating were studied by using Wide Angle X-ray Diffraction (WAXD), Differential Scanning Calorimetry (DSC) and Step Scan DSC. The equilibrium melting point and the enthalpy of fusion of the pure crystalline polymer were found 79.7 oC and 28.9 kJ/mol, respectively. Polarized Light Microscopy (PLM) tests showed that PPSub forms banded spherulites. The Lauritzen-Hoffman theory was used. Values of spherulite growth rates and also overall crystallization rates after self-nucleation, from DSC data, were used. In the latter case the inverse of crystallization half times or the Avrami constant K values were supposed to be a measure of crystallization rates. Critical breakpoint in the Lauritzical breakpoint in the Lauritzen-Hoffman plots appeared at 40 oC showing crystallization regime II to III transition. Non-isothermal crystallization kinetics was also analyzed. Interestingly, the Ozawa model seems to hold for PPSub. The iso-conversional method of Friedman was used to study the activation energy of PPSub crystallization on cooling and the Lauritzen-Hoffman parameters were also calculated by applying the Vyazovkin method.

417

A New Method for Hepatic Resection and Hemostasis: Absorbable Plaque and Suture  

Science.gov (United States)

Objective: Blunt and penetrating hepatic injuries are conditions that are frequently encountered in emergency surgeries, and they involve high mortality morbidity. In the handling of such injuries, methods ranging from the application of simple cauterization and suturing for hemostasis to hepatic lobectomies, which might involve the removal of the greater part of the organ, have been defined. Due to the organ’s fragility and susceptibility to bleeding, elective hepatic resections necessitate both surgical experience and technological equipment. Therefore, the demand still exists for an affordable and easy-to-use-method that could be applied by all centers. Materials and Methods: To meet this demand, we have developed a method of hemorrhage control via sutures supported by absorbable plaques that provide effective compression and prevent the suture from cutting the tissue during the application of the sutures in the treatment of such fragile organs as the liver. In our method, we have achieved hemostasis by bilaterally compressing the tissue through strong ties after placing, on the part of the tissue on which the sutures are applied, absorbable and flexible plaques that prevent the suture from cutting the tissue during the application of a polyglactin suture to the solid organ. To prevent dislocation of the plaques, we have fastened the sutures by reeving them through the holes made in the plaques. Results: We have demonstrated the success and the practicality of our method by applying it on four pigs; we experimentally inflicted hepatic injuries on two pigs, and we performed resection on the other two pigs. The hepatic hemorrhages we developed in both of the animals were successfully restrained by the use of our method. On the other hand, two resections were performed on the right and left lobes of the other two animals. There were no hemorrhages during the surgery, and the procedure took 45 minutes in total. No postoperative complications occurred. While the liver function test values were high on the seventh day, due to the operation, they were observed to be normal on the thirtieth day. After the laparotomies, performed six months later, we observed that the plaques as well as the sutures were absorbed and that the injured tissues were completely healed. Additionally, it was observed during the pathological examination that the tissues beneath the area of application were healed through fibrosis and that the liver had no other pathologies. Conclusions: In conclusion, we believe that the method can be safely used in hepatic resections or traumatic hemorrhages in the proper locations. PMID:25610107

Ozer, M. Tahir; Eryilmaz, Mehmet; Coskun, Kagan; Demirbas, Sezai; Uzar, A. Ihsan; Kozak, Orhan

2010-01-01

418

Nuevo método de sutura subcutánea percutánea continua / New method of continuous percutaneous subcutaneous suture  

Scientific Electronic Library Online (English)

Full Text Available Objetivos: realizar un método de sutura continua, en las personas operadas en el Hospital "Julio Trigo López", que disminuya los granulomas a nivel de la herida quirúrgica, y compararlas con el método tradicional. Métodos: se realizó un estudio experimental sobre la aplicación de un método de sutura [...] subcutánea percutánea continua, en un grupo de pacientes operados de diversas enfermedades, ya sea de urgencia, electivo o ambulatorio, en el Hospital "Julio Trigo López", en los años 2008 y 2009. Resultados: con el método de sutura subcutánea percutánea continua con nylon no se forman granulomas, mientras que con el método tradicional, sí ocurre en un porcentaje no despreciable. Las ventajas del método de sutura subcutánea percutánea continua con nylon son: en el plano celular subcutáneo de la pared abdominal no queda sutura, no se producen granulomas y es más económica. Conclusiones: la sutura de nylon es menos rechazada que la del cromado, ya que no se producen granulomas. El método de sutura subcutánea percutánea continua es una sutura más hemostática que el método tradicional, ya que el por ciento de hematomas es menor. El gasto económico es menor con el método de sutura subcutánea percutánea continua. Con el método de sutura subcutánea percutánea continua la sutura es extraída al 10mo. día de haberla aplicado. Abstract in english Objectives: to apply a continuous suture method to reduce granulomas in surgical wounds in patients operated on at "Julio Trigo Lopez" hospital, and to compare the results with those of the traditional method. Methods: an experimental study was conducted on the application of a continuous percutaneo [...] us subcutaneous suture in a group of patients operated on from several diseases, either under emergency, elective or outpatient conditions at "Julio Trigo Lopez" hospital during 2008 and 2009. Results: the continuous percutaneous subcutaneous suture method with nylon prevents formation of granulomas, whereas the traditional method did show a percentage of granulomas that is not small at all. The advantages of the former are the following: there is no suture left at subcutaneous cellular level of the abdominal wall, granulomas are absent and it is a more economic option. Conclusions: the nylon suture is less rejected than the chromated suture since granulomas do not appear. The continuous percutaneous subcutaneous suture method offers a more hemostatic suture than the traditional method, being the number of hematomas lower. The economic cost is reduced and the suture may be taken out ten days after surgery.

Germán, Brito Sosa; Reinaldo, Echevarría Romero.

2012-06-01

419

Post operation recurrence of inguinal hernia in children and its relation with suture material  

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Full Text Available Background: Using non-absorbable suture in children hernia repair to decrease of recurrence is recommended in the most pediatric surgery centers. The aim of this study was to determine relationship between kind of suture material and rate of hernia recurrence. Methods: In this clinical trial 200 children (age 1-5 years with inguinal hernia who operated in Imam-Reza Hospital (kermanshah –Iran Between April 2007 until April 2008 enrolled into the study. Cases were selected by convenience sampling method and then randomly divided into two groups (100 cases per group and operated with absorbable (silk 3-0 and non-absorbable (vicryli 3-0 suture material. Following period was 12 months after operation and collected data analyzed by statistical software. Emergency operations were excluded from the study.Results: 83% of patients were boy and 17% were girl. %53 showed right side inguinal, 29% left side and %18 were bilateral hernia. After one year follow up only one case of recurrence was observed in each group.Conclusion: Our study confirmed that recurrence of inguinal hernia in children after surgery, is not related to kind of suture material (absorbability and we didn’t find any significant difference. Other factors than suture material may influence recurrence rate of hernia operation in children.

Omid Amanollahi

2011-09-01

420

Vascular anomalies, sutures and small canals of the temporal bone on axial CT  

International Nuclear Information System (INIS)

Purpose: Subtle bony structures, small canals and fine sutures cause sometimes problems in the analysis of CTs of the temporal bone. The aim of this study was: to analyze the visibility of subtle structures and to estimate the incidence of vascular anomalies. Patients and method: We retrospectively analyzed axial scans of 223 high-resolution CTs of the temporal bone obtained as single slice or spiral CT with 1 mm slice thickness. All CTs had clinical indications. Two experienced radiologists studied CTs regarding the visibility of the fine sutures, fissures and small canals and the occurrence of vascular anomalies. Results: The following structures were seen commonly: sphenosquamosal suture (76%), arcuate artery canal (93%), vestibular aqueduct (89%), mastoid emissary vein (82%), singular canal (56%). Not so commonly were observed: tympanosquamosal suture (31%), mastoid canaliculus (28%), lateral sigmoid sinus (28%), petrotympanic fissure (24%), tympanomastoid suture (10%). Seldom we identified: the inferior tympanic canaliculus (6%), high jugular bulb (6%), anterior sigmoid sinus (5%), dehiscent internal carotid artery canal (2%), persistent petrosquamosal sinus (1%), dehiscent jugular bulb (1%). Persistent stapedial artery, aberrant internal carotid artery, dehiscent jugular bulb, high jugular bulb with diverticulum, anterior and dehiscent sigmoid sinus were detected in below 1% of the analyzed temporal bones. The frequency of asymmetry of the jugular foramen, whichof asymmetry of the jugular foramen, which varied between 3% and 42%, depended on different criterions of size. Conclusion: A profound knowledge of normal anatomy and anomalies of the temporal bone avoids misinterpretation as pathological lesions and iatrogenic bleedings

421

SUTURES USING POLYGLACTIN 910 AND TITANIUM STAPLES: URINARY AND UROLITHOGENIC ASPECTS IN EXPERIMENTAL ILEOCYSTOPLASTIES IN DOGS  

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Full Text Available Urinary disorders are an important finding in ileocystoplasty, especially uroliths and crystalluria, and partly related to the type of suture material involved in this procedure. The aim of this study was to determine whether there are differences in the formation of uroliths and urinary crystalloid after ileocystoplasty in dogs, performed by suturing with nonabsorbable titanium staples and suture with polyglactin 910, noting their impact on renal function and urinary changes in the constitution difference in surgical time. Twelve healthy dogs were used and divided into two groups. In each animal was selected a segment of terminal ileum for bladder augmentation. In group A the suture of the detubelized ileal segment to the bladder was made with polyglactin 910 and in group B and the suture was made with titanium clips. We observed the presence of struvite crystals in 11 animals and the formation of large amounts of mucus in urine in all of them. In conclusion, no significant differences between groups in the formation of urinary crystals and uroliths after surgery, group A showed longer duration of surgery and no evidence of change in renal function in both groups.

Gabriela Silva Uchôa

2011-12-01

422

Vascular anomalies, sutures and small canals of the temporal bone on axial CT  

Energy Technology Data Exchange (ETDEWEB)

Purpose: Subtle bony structures, small canals and fine sutures cause sometimes problems in the analysis of CTs of the temporal bone. The aim of this study was: to analyze the visibility of subtle structures and to estimate the incidence of vascular anomalies. Patients and method: We retrospectively analyzed axial scans of 223 high-resolution CTs of the temporal bone obtained as single slice or spiral CT with 1 mm slice thickness. All CTs had clinical indications. Two experienced radiologists studied CTs regarding the visibility of the fine sutures, fissures and small canals and the occurrence of vascular anomalies. Results: The following structures were seen commonly: sphenosquamosal suture (76%), arcuate artery canal (93%), vestibular aqueduct (89%), mastoid emissary vein (82%), singular canal (56%). Not so commonly were observed: tympanosquamosal suture (31%), mastoid canaliculus (28%), lateral sigmoid sinus (28%), petrotympanic fissure (24%), tympanomastoid suture (10%). Seldom we identified: the inferior tympanic canaliculus (6%), high jugular bulb (6%), anterior sigmoid sinus (5%), dehiscent internal carotid artery canal (2%), persistent petrosquamosal sinus (1%), dehiscent jugular bulb (1%). Persistent stapedial artery, aberrant internal carotid artery, dehiscent jugular bulb, high jugular bulb with diverticulum, anterior and dehiscent sigmoid sinus were detected in below 1% of the analyzed temporal bones. The frequency of asymmetry of the jugular foramen, which varied between 3% and 42%, depended on different criterions of size. Conclusion: A profound knowledge of normal anatomy and anomalies of the temporal bone avoids misinterpretation as pathological lesions and iatrogenic bleedings.

Koesling, Sabrina [Department of Diagnostic Radiology, University of Halle, E. Grube Str. 40, 06097 Halle (Germany)]. E-mail: sabrina.koesling@medizin.uni-halle.de; Kunkel, Petra [Department of Diagnostic Radiology, University of Leipzig (Germany); Schul, Thomas [Department of Diagnostic Radiology, University of Leipzig (Germany)

2005-06-01

423

Physical and dielectric properties of irradiated polypropylene and poly(ethylene terephthalate)  

International Nuclear Information System (INIS)

The effect of high-energy electron irradiation in air and in nitrogen on the physical and dielectric properties of polypropylene and poly(ethylene terephthalate) has been studied by measurements of electric strength, dielectric constant, dissipation factor, tensile strength, gel fraction and molecular weight distribution. Electric strength of polypropylene was improved by irradiation, while dielectric properties of poly(ethylene terephthalate) were virtually unaffected by irradiation of 1.0-20 Mrad. Possible mechanisms for increasing electric strength are discussed from the point of view of degradation and oxidation taking place simultaneously with crosslinking of polypropylene. The maximum dose level to improve the electric strength of polypropylene is determined to be about 5 Mrad. (author)

424

Analysis of Flexural Strength for Steel, Glass and Polypropylene Fiber Reinforced Concrete  

OpenAIRE

This analysis study is done by using different types of fibres such as steel, glass and polypropylene with aspect ratio varying from 20 to 120 for steel, 600 to 860 for glass and 30 to 100 for polypropylene fibres.The total fibre percentages of 0 to 2?0for steel, 0 to 2?0for glass and 0 to 2.5?0for polypropylene with variation of 0.25?he design mix varying from M20 to M60 with water cement ratio 0.3 to 0.55 for steel, 0.16 to 0.55 for glass and 0.46 for polypropylene.After being cured...

Venkata Ramana, Chapala Venkata X.; Ch, Naga Sindhura

2012-01-01

425

Long-term stability of irradiated polypropylene fibers and carboxylic cationites on their base  

International Nuclear Information System (INIS)

Study is carried out of polypropylene fibers and fibrous carboxylic cationites on their base, which have been obtained by radiation graft polymerization of acrylic acid by the method of preliminary irradiation of polypropylene fibers on air (gamma-rays of 60Co, dose rate 0.37 Gy/s, dose 5-140 kGy). Mechanical and sorptive properties of polypropylene fibers and cationites are investigated after long-term storage in different conditions. The cationite obtained has excellent sorption properties towards cations of Cd, Pb, Cu. Zn, Fe and etc. It is shown that conditions of graft polymerization and storage influence on long-term stability of carboxylic cationites on the base of polypropylene fibers. It is pointed out that the use of cross-linking agent considerably increases long-term stability of grafted fibers