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21 CFR 878.5010 - Nonabsorbable polypropylene surgical suture.  

Science.gov (United States)

...2010-04-01 false Nonabsorbable polypropylene surgical suture. 878.5010... § 878.5010 Nonabsorbable polypropylene surgical suture. (a) Identification. Nonabsorbable polypropylene surgical suture is a...

2010-04-01

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Evaluation of endoscopic laser excision of polypropylene mesh/sutures following anti-incontinence procedures.  

LENUS (Irish Health Repository)

We reviewed our experience with and outcome of the largest series to our knowledge of patients who underwent endoscopic laser excision of eroded polypropylene mesh or sutures as a complication of previous anti-incontinence procedures.

Davis, N F

2012-11-01

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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)

2014-02-01

4

Deterioration of polypropylene by radiation. Surgical sutures and no additive films. [Gamma radiation and electron  

Energy Technology Data Exchange (ETDEWEB)

Radiation sterilization is not applied to the medical implement using polypropylene because of the severe deterioration by gamma ray irradiation. It has been reported that the chain reaction due to oxygen and peroxide radical contributes to the process of deterioration. The authors concluded that by the irradiation of electron beam, the sterilization of the surgical sutures made of polypropylene is feasible, and reported on the correlation of the lowering of the tensile strength by irradiation and the radical formed. However, the ESR spectra of the radical formed in the surgical sutures made of polypropylene irradiated with electron beam and gamma ray were different from the wave form of the peroxide radical of polypropylene reported before, accordingly, the identification was necessary. By this research, the above ESR spectra were proved by the anisotropy of g of peroxide radical, and the second radical other than the above peroxide radical was found. The experimental method and the results are reported. The research on the deterioration of polypropylene by radiation must be forwarded by examining both conventional peroxide radical P and ''S'' radical.

Minegishi, Atsuko; Imai, Masahiko; Sekiguchi, Masayuki; Tabei, Masae; Sato, Kenji

1984-10-01

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Polypropylene  

International Nuclear Information System (INIS)

Polypropylene is a polymer widely used in lens implantation, both as a loop material and as an intracameral suture. The chemistry and qualities of this material are discussed. Predicated on its usage in other types of surgery, it appears to be resistant to degradation. However, reports have suggested that it may degrade when exposed to high levels of ultraviolet radiation. This would not be a consideration in internal organs, but the eye is a unique case, and the matter should be studied further

1981-01-01

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In-vitro evaluation of the adhesion to polypropylene sutures of non-pigmented, rapidly growing mycobacteria.  

Science.gov (United States)

The ability of non-pigmented, rapidly growing mycobacteria (NPRGM) to attach to polypropylene sutures was evaluated using an in-vitro assay. Thirty clinical isolates and five culture collection strains of NPRGM, together with Staphylococcus epidermidis ATCC 35983, were tested. Mycobacterium fortuitum and Mycobacterium chelonae showed the highest attachment ability, which differed significantly from the results obtained with Mycobacterium peregrinum. According to these results, NPRGM are able to attach to polypropylene sutures, and the species implicated most frequently in human infection showed increased levels of attachment in comparison with the other mycobacteria studied. PMID:17608747

Zamora, N; Esteban, J; Kinnari, T J; Celdrán, A; Granizo, J J; Zafra, C

2007-09-01

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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.

1981-01-01

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Small Bowel Wall Response to Enterotomy Closure with Polypropylene and Polyglactin 910 Using Simple Interrupted Suture Pattern in Rats  

Directory of Open Access Journals (Sweden)

Full Text Available Effects of polypropylene and polyglactin 910 on enterotomy wound healing were investigated. Sixteen adult W istar albino rats (155.44±30.4 g w ere randomized into two study groups, A with polypropylene (n = 8 and B with polyglactin 910 (n = 8 following 1 cm mid-jejunal enterotomy incisions performed under ketamine/xylazine anaesthesia. Body weights changes were evaluated daily for eleven days and two rats from each group were euthanized at postoperative days 3, 5, 7 and 11. Following euthanasia, the enterotomy sites were examined for dehiscence and adhesion. Evidence of inflammatory reactions and fibroblast proliferation were also evaluated and scored. Leaks from enterotomy site were not observed. Adhesion scores in-group A (3.5 was statistically significant (p0.05 but higher fibroblasts count was recorded in Group A (2.625 compared with group B (1.375. Inflammatory responses in both groups were not statistically significant, although that of Group B was higher in response than group A. Enterotomy closure with polypropylene produced significant adhesion that may be linked with the texture of the suture, and the several knots characteristic of the simple interrupted suture pattern.

Eyarefe O. David

2010-07-01

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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  

Directory of Open Access Journals (Sweden)

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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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  

Directory of Open Access Journals (Sweden)

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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New modified iris suture technique for pupillary dilation in aphakic eyes during vitreoretinal surgery  

Digital Repository Infrastructure Vision for European Research (DRIVER)

To describe a modified simple iris suture for pupillary dilation technique during vitrectomy in cases with a miotic pupil. Four translimbal incisions were created with a sharp straight blade at 1:30, 10:30, 4:30, and 7:30 o'clock, respectively. The straight needle of 10-0 polypropylene suture and a Sinskey IOL hook was used to displace the pupillary margin toward the limbus. In 3 cases, four sutures caused a 6-mm to 9-mm square-shaped pupil, and the pupil was allowed to return to a smaller si...

2010-01-01

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Polypropylene; Polypropylene  

Energy Technology Data Exchange (ETDEWEB)

Basell has signed an agreement with the Saudi Sahara Petrochemical firm for the construction of a polypropylene plant of 450000 t/year at Al-Jubail (Saudi Arabia). This project plans the construction of a propane dehydrogenation unit too. These two units should start at the end of the year 2007. (O.M.)

Anon.

2004-12-01

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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  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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 su [...] tura); 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. Abstract in english 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 - Pol [...] ypropylene, 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; Anete Kinumi, Ueda; Marcos Augusto de, Moraes-Silva.

14

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 surgeon and staff's time. (author)

2012-03-01

15

Polypropylene; Polypropylene  

Energy Technology Data Exchange (ETDEWEB)

The Indian Oil Corp. (IOC) firm will build a polypropylene unit of a capacity of 600000 t/year in Panipat (India). The unit should start in 2007. It will use the Spheripol technology of Basell. The propylene unit of IOC is a part of a plan which should lead to the building of a steam-cracker of 800000 t/year and of polyethylenes units on the Panipat site. (O.M.)

Anon.

2004-12-01

16

Polypropylene; Polypropylene  

Energy Technology Data Exchange (ETDEWEB)

Sumitomo Chemical is setting up a Chinese joint-venture for polypropylene compounds with Tokyo Ink. Located at Zhuhai (province of Guangdong), it should dispose, when it will start in the middle of 2006, of a capacity of 10000 t/year, with the possibility to double this capacity later on. The co-firm, Sumikaa Polymer Compounds, will be hold at 55% by Sumitomo and at 45% by Toyo Ink. (O.M.)

Anon.

2005-04-01

17

Sutures - separated  

Science.gov (United States)

... a sign of pressure within the skull ( increased intracranial pressure ). Separated sutures may be associated with bulging fontanelles . If intracranial pressure is increased a lot, there may be large ...

18

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 restrain material degradation. (author)

1986-01-01

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An innovative method to evaluate the suture compliance in sealing the surgical wound lips  

Directory of Open Access Journals (Sweden)

Full Text Available Background and aim: The increasing number of surgical procedures performed with local anesthesia, followed by immediate patient discharge from the hospital, emphasizes the need for a tight waterproof suture that is capable of maintaining its tensile strength in the postoperative phase when the wound tumescence, edema due to the anesthetic drug, and surgical trauma disappear. Moreover, the issue of having an accurate surgical wound closure is very relevant in vivo in order to prevent hemorrhage and exogenous microbial infections. This study aimed at designing a new a lab technique that could be used for evaluating the best surgical material. Using such a technique, we compared the wound-lip-sealing properties of three commonly-used suture threads, namely polyurethane, polypropylene, and polyamide. Materials and methods: The mechanical properties of same-size suture threads made from polyurethane, polypropylene, and polyamide, were compared in order to define the one that possess the best elastic properties by being able to counteract the tension-relaxation process in the first 12 hours following surgery. The tension holding capacity of the suture materials was measured in both in vivo and in vitro experiments. The surface area of the scar associated with the three different suture threads was measured and compared, and the permeability of the three different suture threads was assessed at 0 minute, 2 minute, 4 minute, 6 minute, and 8 minute- interval. Results: Results showed that polyurethane suture threads had significantly (P < 0.05 better tensile strength, elongation endurance before breakage, and better elasticity coefficient as compared to polypropylene and polyamide suture threads. Moreover, polyurethane suture threads were significantly (P < 0.05 more impermeable as compared to the other two suture thread types (polypropylene and polyamide. This impermeability was also associated with a tighter wound-lip-sealing ability, and with significantly (P < 0.05 less scar formation. Conclusion: Among the main concerns that surgeons, physicians, and patients often have is the development infection, oozing, and scar at the incision site following suturing. This always raises the question about which suture to use to avoid the above problems. This study provides evidence that the new technique developed in our lab could be used to compare the wound-lip sealing properties of different surgical suture threads. Using such a technique, the results show that polyurethane is significantly better than other commonly-used suture threads, like polypropylene and polyamide, in relation to wound sealing and scar formation.

Farid Saleh, Beniamino Palmieri, Danielle Lodi, Khalid Al-Sebeih

2008-01-01

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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?  

Directory of Open Access Journals (Sweden)

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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Radiation grafted polypropylene films  

Energy Technology Data Exchange (ETDEWEB)

Irradiation of polypropylene films by gamma or electron beam radiation leads to severe degradation of the polymer. Controlling the polypropylene's morphology upon processing produces a mesomorphic polypropylene film that is resistant to gamma or electron beam radiation for storage periods of at least 4 months. This mesomorphic polypropylene film provides a film base for the graft polymerization of reactive monomers to the film surface to improve such properties as hydrophilicity, hydrophobicity, adhesion and ion exchange capacity. (author).

Rolando, R.J.; Krueger, D.L. (3M Center, St. Paul, MN (USA). Corporate Research)

1990-01-01

22

[Aorto-iliac microbridge by continuous suture in the rat].  

Science.gov (United States)

We have performed micro-anastomoses by continuous suture technic: --circular suture of an aorta with 9/0 and with 10/0 Vicryl three (90% permeability); --next we performed an aortic-iliac bypass thanks to a carotid graft (70% permeability). The verification was carried out by injection of the complete arterial system with solidifying agent, and we obtained an arterial fitting after corrosion by the mean of hydrochloric acid. PMID:6759961

Berthelot, J L; Hureau, J

1982-01-01

23

Suture midface suspension  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Objective To describe a simple and effective facelift technique useful as an adjunct to other oculoplastic procedures Methods Retrospective, non-comparative case series. Thirty five patients undergoing suture midface suspension from 1998 to 2000. Suspension sutures were passed from the nasolabial fold to the temporalis fascia to elevate the midface and the corner of the mouth. Results A satisfactory and stable outcome is obtained in 2 years of follow up. Conclusion Suture midface suspension is a safe and effective technique for the management of midface descent.

Murthy Rachna

2006-11-01

24

Glaucoma laser suture lysis.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

AIM: Suture lysis is commonly performed after trabeculectomy to improve bleb function. It is often thought to be an innocuous procedure. This is the first large study to determine the safety of the procedure and compare results with a control group. METHODS: Two hundred successive trabeculectomies performed between January 1992 and October 1993 were analysed. RESULTS: Ninety nine eyes underwent trabeculectomy and suture lysis; 101 eyes underwent trabeculectomy and did not require postoperativ...

1996-01-01

25

Suture tip plasty.  

Science.gov (United States)

The three main characteristics of the nasal tip are projection, rotation, and contour. During rhinoplasty the surgeon will strive to preserve or change these characteristics in a predictable fashion, avoiding undesirable sequelae, even after long-term follow-up. Conservation, relocation and augmentation rather than reduction are key principles in modern rhinoplasty, i.e. for obtaining gratifying tip surgery. Interdomal suture, transdomal suture, and lateral crural steal follow these modern principles, while having their clear indications for different nasal tip pathology. All three types of techniques involve (semi-)permanent sutures to change the shape of alar cartilages and can be considered complementary. Based on the same surgical philosophy these three techniques can be captured with the term "suture tip plasty". The objective of this paper is to describe, in a retrospective fashion, a series of 112 patients in whom suture tip plasty has been used as part of the rhinoplasty procedure. The technique proved versatile with predictable results and few manageable complications. PMID:7784792

Vuyk, H D

1995-03-01

26

Heat welding for surgical sutures.  

Science.gov (United States)

The purpose of this experimental study was to test the potential value of heat welding to cut the ends of knotted surgical sutures. This heat process resulted in knot security in a coated polyglactin suture with fewer throws than those needed for the same suture with knotted ends cut by scissors. Results of mechanical performance testing of the knotted sutures cut either by scissors or welding did not differ significantly. With refinements in the technical design of the heat source, suture welding may have important applications in surgery. PMID:3898890

Masterson, T M; Thacker, J G; Rodeheaver, G T; Edlich, R F

1985-09-01

27

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

28

Radiation stability of polypropylene  

International Nuclear Information System (INIS)

Disposable medical products which are formed from polypropylene are readily degraded by high-energy irradiation encountered during the radiation sterilization cycle. Examination of irradiated polypropylene by electron spin resonance indicates that the degradative process is mainly oxidative. In addition, results show that physical properties decrease rapidly with increasing absorbed dose. More importantly, the physical properties continue to deteriorate with time following irradiation. This post-degradative reaction is oxidative in nature and is initiated mainly by residual radicals following the sterilization cycle. Physical property results indicate that certain polypropylenes that might be acceptable immediately following irradiation would be totally unacceptable after six months due to post-degradation. (author)

1976-05-13

29

First investigation of spider silk as a braided microsurgical suture.  

Science.gov (United States)

Inhibition of axonal outgrowth accompanied by neuroma formation appears in microsurgical nerve repair as reaction to common microsuture materials like silk, nylon, or polyglycolic acid. In contrast, recent findings revealed advantages of spider silk fibers in guiding Schwann cells in nerve regeneration. Here, we asked if we could braid microsutures from native spider silk fibers. Microsutures braided of native spider dragline silk were manufactured, containing either 2 × 15 or 3 × 10 single fibres strands. Morphologic appearance was studied and tensile strength and stress-strain ratio (SSR) were calculated. The constructed spider silk sutures showed a median thickness of 25 ?m, matching the USP definition of 10-0. Maximum load and tensile strength for both spider silk microsutures were significantly more than 2-fold higher than for nylon suture; SSR was 1.5-fold higher. All values except elasticity were higher in 3 × 10 strand sutures compared to 2 × 15 strand sutures, but not significantly. In this pilot study, we demonstrate the successful manufacture of microsutures from spider silk. With regards to the mechanical properties, these sutures were superior to nylon sutures. As spider silk displays high biocompatibility in nerve regeneration, its usage in microsurgical nerve repair should be considered. PMID:21432995

Kuhbier, Joern W; Reimers, Kerstin; Kasper, Cornelia; Allmeling, Christina; Hillmer, Anja; Menger, Björn; Vogt, Peter M; Radtke, Christine

2011-05-01

30

Radiation stability of polypropylene  

International Nuclear Information System (INIS)

Results are presented of an investigation into the effect of gamma radiation on polypropylene. The effects observed were dislocation and oxidative embrittlement. Reaction mechanisms are discussed. (U.K.)

1979-03-29

31

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

1992-08-23

32

Fiber Pave, Polypropylene Fiber.  

Science.gov (United States)

The report documents the performance of Fiber Pave. Fiber Pave 3010, which is manufactured by Hercules Incorporated, consists of short-length polypropylene fibers designed for use as a reinforcement in bituminous concrete and asphalt pavements. It is mark...

D. S. Harmelink

1992-01-01

33

Radiation resistant modified polypropylene  

International Nuclear Information System (INIS)

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

1997-05-26

34

A prototype haptic suturing simulator.  

Science.gov (United States)

A new haptic simulation designed to teach basic suturing for simple wound closure is described. Needle holders are attached to the haptic device as the graphics of the needle holders, needle, sutures and virtual skin are displayed and updated in real time. The simulator incorporates several interesting components such as real-time modeling of deformable skin, tissue and suture material and real-time recording of state of activity during the task using a finite state model. PMID:11317811

Webster, R W; Zimmerman, D I; Mohler, B J; Melkonian, M G; Haluck, R S

2001-01-01

35

Comparative study between two techniques of incisional hernia repair with polypropylene mesh in rabbits Estudo comparativo entre duas técnicas de tratamento da hérnia incisional em coelhos utilizando a tela de polipropileno  

Digital Repository Infrastructure Vision for European Research (DRIVER)

PURPOSE: To compare two different incisional hernia repair techniques (repair with a polypropylene mesh reinforcement on the peritonium-aponeurosis versus polypropylene mesh sutured to the borders of the hernial ring as a bridge) in rabbits. METHODS: Incisional hernia was experimentally developed through a 4-cm median incision in 60 rabbits. After 30 days, half of the animals were operated for primary wall closure and placement of a polypropylene mesh reinforcement, while the other half had a...

José Guilherme Minossi; Carlos Antonio Caramori; Celso Vieira de Souza Leite; Luiz Eduardo Naresse

2010-01-01

36

Biodegradation of Polypropylene Nonwovens  

Science.gov (United States)

The primary aim of the current research is to document the biodegradation of polypropylene nonwovens and filament under composting environments. To accelerate the biodegradat ion, pre-treatments and additives were incorporated into polypropylene filaments and nonwovens. The initial phase (Chapter 2) of the project studied the biodegradation of untreated polypropylene with/without pro-oxidants in two types of composting systems. Normal composting, which involved incubation of samples in food waste, had little effect on the mechanical properties of additive-free spunbond nonwovens in to comparison prooxidant containing spunbond nonwovens which were affected significantly. Modified composting which includes the burial of samples with food and compressed air, the polypropylene spunbond nonwovens with/without pro-oxidants displayed an extreme loss in mechanical properties and cracking on the surface cracking. Because the untreated spunbond nonwovens did not completely decompose, the next phase of the project examined the pre-treatment of gamma-irradiation or thermal aging prior to composting. After exposure to gamma-irradiation and thermal aging, polypropylene is subjected to oxidative degradation in the presence of air and during storage after irradiat ion. Similar to photo-oxidation, the mechanism of gamma radiation and thermal oxidative degradation is fundamentally free radical in nature. In Chapter 3, the compostability of thermal aged spunbond polypropylene nonwovens with/without pro-oxidant additives. The FTIR spectrum confirmed oxidat ion of the polypropylene nonwovens with/without additives. Cracking on both the pro-oxidant and control spunbond nonwovens was showed by SEM imaging. Spunbond polypropylene nonwovens with/without pro-oxidants were also preirradiated by gamma rays followed by composting. Nonwovens with/without pro-oxidants were severely degraded by gamma-irradiation after up to 20 kGy exposure as explained in Chapter 4. Furthermore (Chapter 5), gamma-irradiated polypropylene nonwovens with pro-oxidants were invisible to the naked eye after 30 days of composting suggesting microbial attack was achieved. The final phase of the project encompasses the extrusion of bicomponent fibers. Because microorganisms desire to feed on hydrophilic molecules, commercially available starch-based polymers were spun with polypropylene resins in a sheath/core configuration. Similar to the previously discussed nonwovens studies, the bicomponent filaments were pretreated with heat (Chapter 6) and gamma-rays (Chapter 7) before evaluating the biodegradability under composting studies. The results from these chapters were reviewed to determine if bicomponent nonwovens under the same conditions could be manufactured.

Keene, Brandi Nechelle

37

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

38

Vascular closure stapler clip anastomosis decreases aortic cross-clamping time compared to interrupted nonabsorbable and running absorbable sutures in growing pigs.  

Science.gov (United States)

The latest generation in titanium clip application systems, the vascular closure staples (VCS) system avoids intimal lesions and therefore minimizes the subsequent hyperplastic reaction, while at the same time enhancing distensibility and vascular growth. Moreover, VCS clips allow the surgeon to perform vascular anastomosis easily and faster than conventional suture. This system may become the option of choice for vascular reconstruction in pediatric surgery where, as in the case of aortic and transplant surgery, decreasing vascular occlusion times may influence the outcomes. The aim of this study was to determine whether VCS metallic clips would allow shorter anastomosis times than conventional interrupted polypropylene or running Dexon suturing in end-to-end anastomosis performed in the abdominal aorta of young pigs. Twenty-four domestic swine, 45 days old, were used for this study. All animals were subjected to an end-to-end anastomosis in the abdominal aorta using VCS clips, interrupted polypropylene, or running Dexon suture. Aortic cross-clamping time was significantly shorter in the VCS clips group (4.02 +/- 0.72 min), compared to interrupted polypropylene (21.89 +/- 1.93 min) or running Dexon (9.82 +/- 3.97 min) suture. VCS clips are easy to use, and therefore may aid surgeons to significantly decrease the time needed for performing an end-to-end anastomosis in the abdominal aorta, thus decreasing cross-clamping time when compared to interrupted polypropylene or running Dexon sutures. PMID:16378146

Calles-Vázquez, María Carmen; Viguera, Francisco Javier; Crisóstomo, Verónica; Usón-Gargallo, Jesús

2006-01-01

39

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

1994-01-01

40

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

 
 
 
 
41

Arthroscopic Suture Anchor Tenodesis: Loop-Suture Technique  

Science.gov (United States)

With advancements in arthroscopic surgery, arthroscopic biceps tenodesis with suture anchor recently has been reported to be a reasonable option for the treatment of biceps pathologies, especially for those that are symptomatic or accompanied by a rotator cuff tear. We introduce our technique of arthroscopic biceps tenodesis with suture anchor that we call the loop-suture technique, which is constructed with 1 loop strand and another sutured strand. This technique can help to improve biceps grip and simultaneously minimize longitudinal splitting of the tendon. In addition, it is relatively simple and can be performed with the use of conventional devices and arthroscopic portals used for rotator cuff repair, without the formation of additional portals or a separate incision for the tenodesis.

Shon, Min Soo; Koh, Kyoung Hwan; Lim, Tae Kang; Lee, Seung Won; Park, Young Eun; Yoo, Jae Chul

2013-01-01

42

Physical properties of novel polypropylenes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

High molecular polypropylene (MW ~ 1,100,000 g/mol) was added to a matrix of polypropylene with an average molecular weight (MW ~ 250,000 g/mol). By blending both materials we tried to combine the respective advantages regarding stability and processability. The long chains from the high molecular polypropylene act as tie molecules between the crystalline regions in the polymers, providing direct covalent bonds. Theoretical calculations showed that the probability for tie molecules is abo...

Fischer, Stefan

2009-01-01

43

Spectropolarimetry of SNR G296.5+10.0  

CERN Multimedia

Radio continuum emission from the supernova remnant G296.5+10.0 was observed using the Australia Telescope Compact Array. Using a 104 MHz bandwidth split into 13 x 8 MHz spectral channels, it was possible to produce a pixel-by-pixel image of Rotation Measure (RM) across the entire remnant. A lack of correlation between RM and X-ray surface brightness reveals that the RMs originate from outside the remnant. Using this information, we will characterise the smooth component of the magnetic field within the supernova remnant and attempt to probe the magneto-ionic structure and turbulent scale sizes in the ISM and galactic halo along the line-of-sight.

Harvey-Smith, L; Ng, C -Y; Green, A J

2008-01-01

44

Fiber reinforced polypropylene nanocomposites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this thesis is to assess the feasibility of integrating nanoparticles into glass fiber (GF) reinforced isotactic polypropylene (iPP) composites via existing thermoplastic processing routes, and to investigate whether this results in significant improvements in the mechanical properties of the final composites. A longer term aim will be to extend the approach to the preparation of hybrid composites with added non-structural functionality. However, the nanoparticles that have provide...

Houphouet-boigny, Chryste?le

2007-01-01

45

Sutured Floer homology and hypergraphs  

CERN Document Server

By applying Seifert's algorithm to a special alternating diagram of a link L, one obtains a Seifert surface F of L. We show that the support of the sutured Floer homology of the sutured manifold complementary to F is affine isomorphic to the set of lattice points given as hypertrees in a certain hypergraph that is naturally associated to the diagram. This implies that the Floer groups in question are supported in a set of Spin^c structures that are the integer lattice points of a convex polytope. This property has an immediate extension to Seifert surfaces arising from homogeneous link diagrams (including all alternating and positive diagrams). In another direction, together with work in progress of the second author and others, our correspondence suggests a method for computing the "top" coefficients of the HOMFLY polynomial of a special alternating link from the sutured Floer homology of a Seifert surface complement for a certain dual link.

Juhász, András; Rasmussen, Jacob

2011-01-01

46

[Laparoscopic suture and knot techniques].  

Science.gov (United States)

Laparoscopic suture and knot techniques are not yet considered standard laparoscopic procedures. In conventional surgery, it would be unthinkable that a procedure would be attempted without a good working knowledge of suture and knot techniques. In laparoscopic operations, limited mobility, the lever arm through the instruments and especially the conversion of 2D vision to 3D actions and the lack of a direct tactile sense all have limiting effect. The needle holders available leave room for improvement. The initially protracted operating times become shorter with training and a period of adjustment. PMID:8050302

Pier, A; Thevissen, P; Eikel, M; Götz, F

1994-05-01

47

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

48

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

49

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)

2008-01-01

50

21 CFR 878.4495 - Stainless steel suture.  

Science.gov (United States)

...suture. (a) Identification. A stainless steel suture is a needled or unneedled nonabsorbable surgical suture composed of 316L stainless steel, in USP sizes 12-0 through 10, or a substantially equivalent stainless steel suture, intended for...

2009-04-01

51

Flexor Tenorrhaphy Using Absorbable Suture Materials  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2012-01-01

52

Unusual sutural bones at pterion  

Directory of Open Access Journals (Sweden)

Full Text Available The existence of Wormian (sutural bones in the skull is well known. We found three unusual Wormian bones at the right pterion in an adult Indian skull. The variation noted was unilateral. This type of variation has not been reported yet.

Nayak SB

2008-08-01

53

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)

2009-10-13

54

Silk suture in cesarean section  

Directory of Open Access Journals (Sweden)

Full Text Available We present a small series of 114 cases observed during 4 years in the Clínica deMaternidad Rafael Calvo Cartagena, as part of a more extensive experience with the silkthread suture in cesarean section. The characteristics and advantages of this thread andthe technicalities of the suture in each plane are explained, recommending, especiallywith regard of uterine muscle, our system of single simple interrupted sutures. We callattention to the postoperative locks of surgical wound. We have included this work withtwo tables about causes of surgery and features of anesthetic technique used.RESUMEN:Presentamos una serie de 114 casos observados durante 4 años en la clínica MaternidadRafael Calvo Cartagena. Como parte de una más dilatada experiencia sobre la suturaen cesáreas con hilo de seda. Se explican las características y ventajas de este hilo ylas modalidades técnicas de la sutura en cada plano, recomendando, especialmente encuanto al músculo uterino, nuestro sistema de una sola costura a puntos separados.Llamamos la atención sobre los candados postoperatorios de la herida quirúrgica.Adicionamos el presente trabajo con dos cuadros relativos a las causas de intervencióny a algunas característica de la anestesia utilizada.

Milanés-Pernet Jorge

2011-06-01

55

Suture anchors--update 1999.  

Science.gov (United States)

New suture anchors continue to become available. Our prior reports on the pullout strength of over 50 different anchors is supplemented by a similar test conducted on 25 additional new anchors. This anchor comparison, using an established protocol in fresh porcine femurs, recorded failure strength, failure mode (anchor pullout, suture eyelet cutout, or wire breakage), eyelet size, minor and major diameters, and drill hole sizes. These new anchors were tested in diaphyseal cortex, metaphyseal cortex, and a cancellous trough. Tensile stress parallel to the axis of insertion was applied at a rate of 12.5 mm/sec by an Instron 1321 until failure and mean anchor failure strengths were calculated. Anchors tested included DePuy 4.5 prototypes D1, D2 Catera 4.5, and D3; DePuy 3.5 prototypes D4- Catera 3.5, D5, and D6; Mainstay 2.7, 3.5, 4.5; ROC EZ 2.8, EZ 3.5, and XS 3.5; Ultrafix RC and Ultrafix MiniMite; 1.3 MicroMitek, Panalok 3.5, and Tacit 2.0; Umbrella Harpoon; PeBA 2.8, 4.0, 6.5; and Stryker 1.9, 2.7, 3.4, and 4.5 prototypes. Screw anchors still tend to have higher values, but for the newer nonscrew designs this distinction is less apparent. The new biodegradable anchors were all composed of poly L-lactic acid suggesting a trend away from other polymers, and these new biodegradable anchors showed load-to-failure strengths comparable to others in their class. All anchors were stronger than the suture for which they are designed to accommodate. PMID:10524819

Barber, F A; Herbert, M A

1999-10-01

56

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

57

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)

1986-01-01

58

Polypropylene mesh: evidence for lack of carcinogenicity.  

Science.gov (United States)

Tumors related to the implantation of surgical grade polypropylene in humans have never been reported. In this commentary we present a balanced review of the information on what is known regarding the host response to polypropylene and provide data as to why the potential for carcinogenicity of polypropylene mesh is exceedingly small. PMID:24614956

Moalli, Pamela; Brown, Bryan; Reitman, Maureen T F; Nager, Charles W

2014-05-01

59

USE OF POLYPROPYLENE MESH FOR INCISIONAL HERNIA REPAIR  

Directory of Open Access Journals (Sweden)

Full Text Available Incisional hernia is an important complication of abdominal surgery. Procedures for the repair of these hernias with sutures and with mesh have been reported, but there is no consensus about which type of procedure is the best. We have performed a retrospective analysis on 1128 patients operated on in our unit between 1994 and 2004 for simple or recurrent incisional hernias. The polypropylene mesh has been used in a number of 138 patients. The mesh has been placed either intraperitoneal, extraperitoneal/ subfascial or onlay. Median follow-up was 36 months. There were 1 enterocutaneous fistula and 5 wound sinus developed. The mesh had to be removed in 6 cases. All of these complication developed when the mesh has been placed either extraperitoneally/subfascial or onlay. We note 5 recurrent incisional hernias after a period of up to 24 months. The recurrence rates after open mesh repair are less then after primary closure. The intraperitoneal use of polypropylene mesh with omental coverage is a good procedure with less complications.

Scripcariu V

2006-07-01

60

21 CFR 878.5020 - Nonabsorbable polyamide surgical suture.  

Science.gov (United States)

...2009-04-01 false Nonabsorbable polyamide surgical suture. 878.5020 Section...Devices § 878.5020 Nonabsorbable polyamide surgical suture. (a) Identification. Nonabsorbable polyamide surgical suture is a...

2009-04-01

 
 
 
 
61

Needle and suture contamination in strabismus surgery  

Directory of Open Access Journals (Sweden)

Full Text Available Objective: To evaluate the level of bacterial contamination of needles and sutures used in strabismus surgery. Material and Methods: Strabismus surgery was performed on 30 eyes of 20 patients in our clinic between January 2004 and June 2004. Preoperative site preparation included installation of 5% povidine-iodine in the conjunctival fornices in all cases. A total of 60 needles and 60 sutures were cultured immediately after final scleral passage. Results: Ten of the 20 cases (50% produced at least one positive specimen. 8.3% of the needles and 15% of the sutures were culture positive. In all culture positive specimens 40% of the needles and 55% of the sutures produced 3 or less colony forming units (CFU. 4-6 CFU in 20% of needles and 11% of sutures, 7 or more CFU in 40% of needles and 34% of sutures were demonstrated accordance with dilution scheme. Coagulase-negative staphylococci were overwhelmingly predominated. Conclusion: The amount of bacterial contamination is usually below the level known to produce endophthalmitis in strabismus surgery. Needles and sutures used in strabismus surgery can become contaminated during surgery despite povidine-iodine usage. Needles and sutures with high contamination could potentially cause postoperative intraocular infection.

Betül Tu?cu

2007-01-01

62

Electron induced modification in polypropylene  

Energy Technology Data Exchange (ETDEWEB)

The effect of 23 kGy dose of 2 MeV electron irradiation on polypropylene has been studied by different characterisation techniques, viz. Fourier transform IR spectroscopy, electron spin resonance spectroscopy, thermogravimetric analysis, differential scanning calorimetry and X-ray diffraction analysis. The thermal stability of the polymer was found to be increasing due to electron irradiation. The thermal decomposition temperature as well as the melting temperature in case of irradiated polypropylene was found to increase due to electron bombardment. The isotactic nature of the polymer was found to be unaffected by electron irradiation. An increase in crystallinity of the polymer has also been observed after irradiation.

Mishra, R. E-mail: rosymishra@email.com; Tripathy, S.P.; Dwivedi, K.K. E-mail: kkdau@hotmail.com; Khathing, D.T.; Ghosh, S.; Mueller, M.; Fink, D

2001-12-01

63

Polypropylene-Process selection criteria  

Energy Technology Data Exchange (ETDEWEB)

Production based on traditional catalysts involved, after the polymerization reaction, catalyst residues removal (deashing) and separation of isotactic polypropylene (desired product) from atactic polypropylene (low-value product). The deashing reaction poisoned the unreacted monomers and any solvents, requiring purification of these before recycle to the reaction. An effluent treatment section was also needed. The new catalysts developed by Montedison* in cooperation with Mitsui Petrochemicals in the last few years allow the polymer structure, yield, selectivity and morphology to be controlled in the reaction stage. The production processes have therefore been drastically simplified. In addition, the complete control over catalysis has resulted in remarkable quality improvements and in an expanded product range.

Di Drusco, G.; Rinaldi, R.

1984-11-01

64

The use of imbricated sutures in radioactive plaque brachytherapy surgery  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper describes a new technique to suture the radioactive plaque to sclera. The radioactive plaque is conventionally sutured to the sclera using 5/0 nylon sutures. The imbricated suture technique involves using a 1/0 silk or 2/0 mersilene suture imbricated with the 5/0 nylon suture when the nylon suture is tied and cut. The imbricated suture technique allows easy identification of the plaque at removal and provides a surface that separates the 5/0 nylon from the surface of the eyelet pla...

2010-01-01

65

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

66

Endoscopic dacryocystorhinostomy with flap suturing.  

Science.gov (United States)

Multiple reports have demonstrated the efficacy of endoscopic dacryocystorhinostomy (DCR). However the results of the same have varied from centre to centre. Many still regard external DCR as the gold standard. To describe an endoscopic DCR technique which anatomically simulates an external DCR and assess its results. Prospective, nonrandomized and noncomparative interventional case series. Clinical charts of patients with nasolacrimal duct obstruction based on symptomatic, clinical and radiological basis were included in the study. All surgeries were done endonasally using standard operative technique. The modification in the standard technique included creating a wide exposure of the lacrimal sac, incising the sac and the suturing the medial wall of the lacrimal sac with the lateral nasal wall. The same was achieved by using either vascular clips or 5.0 vicryl sutures. Twenty (11 females and 9 males) were included in the study. The average age of the patients was 56.86 years old (range 27-85 years old). The main presenting symptom was epiphora and 1 patient with mucocele. Successful outcome was measured in terms of relief of sympto anatomical patency assessed by sac syringing and nasal endoscopy showing a wide patent lumen. A primary success rate of 95% and ultimate rate of 100% was achieved in the cases with a nasolacrimal duct (NLD) block while an overall success rate of 82.6% was noted when the cases with NLD block and common canalicular block were considered together. Endoscopic DCR can now easily replace external DCR as a standard. It is not only minimally invasive, but has minimal complications and using this technique, we have been able to achieve very high success rates. PMID:24427653

Kirtane, Milind V; Lall, Abhineet; Chavan, Kashmira; Satwalekar, Dhruv

2013-08-01

67

The double loop mattress suture.  

Science.gov (United States)

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 both a novel porcine loading chamber and mechanical model. Wound apposition is assessed by electron microscopy. The performance of the double loop mattress in vivo was confirmed using a series of 805 pediatric laparotomies/laparoscopies. The double loop mattress suture is 3.5 times stronger than the loop mattress in muscle and 1.6 times stronger in cartilage (p???0.001). Additionally, the double loop mattress reduces tissue tension by 66% compared with just 53% for the loop mattress (p???0.001). Wound gapping is equal, and wound eversion appears significantly improved (p???0.001) compared with the loop mattress in vitro. In vivo, the double loop mattress performs as well as the loop mattress and significantly better than the mattress stitch in assessments of wound eversion and dehiscence. There were no episodes of stitch extrusion in our series of patients. The mechanical advantage of its intrinsic pulley arrangement gives the double loop mattress its favorable properties. Wound dehiscence is reduced because this stitch type is stronger and exerts less tension on the tissue than the mattress stitch. We advocate the use of this novel stitch wherever a high-strength, low-tension repair is required. These properties will enhance wound repair, and its application will be useful to surgeons of all disciplines. PMID:24698436

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

2014-05-01

68

Radiofrequency and its effect on suture strength.  

Science.gov (United States)

The use of radiofrequency-based electrocautery for hemostasis and ablation within the subacromial space and glenohumeral joint can cause damage to suture material. Prior studies have focused on the mechanical properties of sutures including their ability to withstand abrasion. The purpose of this study was to determine the effect of electrical energy on the mechanical properties of 5 different brands of #2 suture used for arthroscopic shoulder repair: FiberWire (Arthrex Inc, Naples, Florida); Orthocord (DePuy Mitek, Norwood, Massachusetts); Hi-Fi (formally Herculine; Linvatec Corp, Largo, Florida); MaxBraid (Teleflex Medical, Research Triangle Park, North Carolina); and Ethibond (Ethicon, Inc, Somerville, New Jersey). A matched pair of human deltoid muscle submerged in buffered saline solution (pH 7.4) was used as a test medium. The suture strengths were tested in 3 different scenarios. The 3 groups were as follows: control group without electrical current, coagulation group with direct introduction of electrical current on a coagulate setting for 2 seconds, and a cutting group with direct introduction of electrical current on a cut setting for 2 seconds. Hi-Fi suture seemed to be the least susceptible to damage by direct electrocautery application. Orthocord suffered the greatest loss of strength of all materials tested. This study demonstrates that exposure to electrocautery damages and weakens suture. Great care should be taken when electrocautery is used during arthroscopic repairs to prevent suture failure and preserve repair integrity. PMID:19968222

Shah, Anup A; Kang, Parminder; Deutsch, Allen

2009-12-01

69

Metopic sutural closure in the human skull.  

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The present study reveals the presence in the sutural area of secondary cartilage, assuring the passive growth of the bones and undergoing an endochondral ossification, but without playing a direct role in the synostosis. The chondroid tissue is responsible for the growth of each frontal bone towards the other and constitutes the first bridge of union between the two bones. It is the most important finding in this study, which provides a description of the closure of the metopic suture and of...

Manzanares, M. C.; Goret-nicaise, M.; Dhem, A.

1988-01-01

70

Effects of primary suture and fib sealant on hemostasis and liver regeneration in an experimental liver injury  

Directory of Open Access Journals (Sweden)

Full Text Available AIM: To investigate the effects of fib sealant on hemostasis and liver regeneration and intra-abdominal adhesions in an experimental liver injury.METHODS: Thirty-six Wistar rats were randomly divided into primary suture group (n = 15, fib sealant group (n = 15 and control group (n = 6. A wedge resection was performed on the left lobe of the liver. In primary suture group, liver was sutured using polypropylene material, while fib glue was administrated on the liver surface in fib sealant group.RESULTS: More intra-abdominal adhesions were observed in the primary suture group compared to the fib sealant group on 3rd (2.50 ± 0.5 vs 0.25 ± 0.5, P = 0.015, 10th (2.75 ± 0.5 vs 0.50 ± 0.6, P = 0.06 and 20th (1.75 ± 0.5 vs 0.70 ± 0.5, P = 0.015 postoperative days. Histopathological scores were better in the fib sealant group in comparison with the primary suture group on 3rd (8.75 ± 0.5 vs 6.75 ± 0.5, P = 0.006, 10th (7.50 ± 1.0 vs 5.5 ± 0.6, P = 0.021 and 20th (6.40 ± 1.7 vs 3.20 ± 1.6, P = 0.025 postoperative days.CONCLUSION: Out data suggest that fib sealant is preferred over primary suture in appropriate cases including liver trauma since it causes less intra-abdominal adhesions while allowing shorter hemostasis time as assessed in experimental liver trauma.

Arif Hakan Demirel, Ozgur Taylan Basar, Ali Ulvi Ongoren, Erkut Bayram, Mustafa Kisakurek

2008-01-01

71

Fracture Toughness Studies of Polypropylene- Clay Nanocomposites and Glass Fibre Reinfoerced Polypropylene Composites  

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In this paper, a comparative study on the fracture toughness of woven glass fibre reinforced polypropylene, chopped glass fibre reinforced polypropylene and nanoclay filled polypropylene composites is presented. Nanoclays (Cloisite 15A) of 1 wt. % to 5 wt. % were filled in polypropylene (PP) matrix and they were subjected to fracture toughness stu-dies. The specimen with 5 wt. % nanoclay showed 1.75 times and 3 times improvement in critical stress intensity factor (KIC) and strain energy rele...

Ramsaroop, A.; Kanny, K.; Mohan, T. P.

2010-01-01

72

Alkali burn versus suture-induced corneal neovascularization in C57BL/6 mice: An overview of two common animal models of corneal neovascularization.  

Science.gov (United States)

The purpose of the present study was to quantify and compare corneal hem- and lymphangiogenesis between alkali burn and suture-induced corneal neovascularization (CNV) in two commonly used mouse strains. A retrospective analysis was performed on C57BL/6 and FVB neovascularized corneas. CNV was induced by surface caustication with NaOH or intrastromal placement of three 10.0 nylon sutures. Hemangiogenesis and lymphangiogenesis extent was calculated on whole mounted corneas by CD31 and LYVE1 immunofluorescence analysis. Blood vessel growth was similar between alkali burn and suture-induced CNV in C57BL/6 mice, and between C57BL/6 and FVB sutured strains. On the contrary, corneal lymphangiogenesis was more pronounced in the C57BL/6 sutured mice versus the alkali burn group, and in the FVB strain versus both C57BL/6 models. These results indicate that significant differences occur in lymphangiogenesis, but not hemangiogenesis, in the alkali burn and suture-induced models in C57BL/6 mice. Furthermore, lymphangiogenesis is more pronounced in the albino (FVB) strain after suture placement. We suggest that the suture model has a number of advantages and may be preferentially used to study corneal lymphangiogenesis. PMID:24560796

Giacomini, Chiara; Ferrari, Giulio; Bignami, Fabio; Rama, Paolo

2014-04-01

73

Massive obstetric haemorrhage following removal of a cervical suture  

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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

74

Woodflour as Reinforcement of Polypropylene  

Directory of Open Access Journals (Sweden)

Full Text Available The effect of the filler content and size, as well as accelerated aging on the mechanical properties of polypropylene composites reinforced with woodflour (WF/PP were evaluated. The composites were prepared by the extrusion of polypropylene with woodflour (Pinus elliotti based on following ratios: 15, 25 and 40 wt% with two different granulometries. The specimens were injection molded according to ASTM standards. The composite properties did not show significant differences as a function of the filler granulometry. We also observed that by increasing the filler content, both the mechanical properties and the melt flow index (MFI decreased, and the elasticity modulus, hardness and density increased. Concerning the accelerated aging, the composite presented a reduction in tensile properties. The results showed that the composite properties are extremely favorable when compared to other commercial systems reinforced by inorganic fillers.

Caraschi José Cláudio

2002-01-01

75

Woodflour as Reinforcement of Polypropylene  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The effect of the filler content and size, as well as accelerated aging on the mechanical properties of polypropylene composites reinforced with woodflour (WF/PP) were evaluated. The composites were prepared by the extrusion of polypropylene with woodflour (Pinus elliotti) based on following ratios: [...] 15, 25 and 40 wt% with two different granulometries. The specimens were injection molded according to ASTM standards. The composite properties did not show significant differences as a function of the filler granulometry. We also observed that by increasing the filler content, both the mechanical properties and the melt flow index (MFI) decreased, and the elasticity modulus, hardness and density increased. Concerning the accelerated aging, the composite presented a reduction in tensile properties. The results showed that the composite properties are extremely favorable when compared to other commercial systems reinforced by inorganic fillers.

José Cláudio, Caraschi; Alcides Lopes, Leão.

76

Laparoscopic surgery for giant adult bochdalek diaphragmatic hernia: combined suturing and polypropylene mesh repair.  

Science.gov (United States)

Congenital diaphragmatic hernias occur through embryologic defects in the diaphragm. A subset of adults (5-10 %) may present with a congenital hernia undetected during childhood. It requires surgery because of the risk of incarceration. An old lady having vomiting, upper abdominal pain, dyspnoea and retrosternal discomfort was diagnosed with the presence of a large left-sided Bochdalek diaphragmatic hernia and a hypoplastic lung. Laparoscopic repair was performed successfully after adequate preparation. The patient had postoperative respiratory difficulty and needed mechanical ventilation and intensive care for 5 days. She was discharged 8th POD. There was no recurrence in 32 months follow-up, though the hypoplastic left lung never recovered. Laparoscopy is proving to be more beneficial than laparotomy or thoracotomy. The use of a mesh further strengthens the defect and reduces chance of recurrence. PMID:17785133

Palanivelu, Chinnusamy; Rangarajan, Muthukumaran; Senthilkumar, Ramakrishnan; Madankumar, Madhupalayam Velusamy

2007-08-01

77

Functional implications of squamosal suture size in paranthropus boisei.  

Science.gov (United States)

It has been hypothesized that the extensively overlapping temporal and parietal bones of the squamosal sutures in Paranthropus boisei are adaptations for withstanding loads associated with feeding. Finite element analysis (FEA) was used to investigate the biomechanical effects of suture size (i.e., the area of overlap between the temporal and parietal bones) on stress, strain energy, and strain ratio in the squamosal sutures of Pan troglodytes and P. boisei (specimen OH 5) during biting. Finite element models (FEMs) of OH 5 and a P. troglodytes cranium were constructed from CT scans. These models contain sutures that approximate the actual suture sizes preserved in both crania. The FEM of Pan was then modified to create two additional FEMs with squamosal sutures that are 50% smaller and 25% larger than those in the original model. Comparisons among the models test the effect of suture size on the structural integrity of the squamosal suture as the temporal squama and parietal bone move relative to each other during simulated premolar biting. Results indicate that with increasing suture size there is a decreased risk of suture failure, and that maximum stress values in the OH 5 suture were favorable compared to values in the Pan model with the normal suture size. Strain ratios suggest that shear is an important strain regime in the squamosal suture. This study is consistent with the hypothesis that larger sutures help reduce the likelihood of suture failure under high biting loads. PMID:24242913

Dzialo, Christine; Wood, Sarah A; Berthaume, Michael; Smith, Amanda; Dumont, Elizabeth R; Benazzi, Stefano; Weber, Gerhard W; Strait, David S; Grosse, Ian R

2014-02-01

78

Production, characterization, and modeling of mineral filled polypropylene filaments  

Science.gov (United States)

This research produced mineral filled polypropylene filaments using a variety of fillers, characterized these filaments, and attempted to model their mechanical properties with current composite models. Also, these filaments were compared with bone to determine if they are suitable for modeling the mechanical properties of bone. Fillers used consist of wollastonite, talc, calcium carbonate, titanium dioxide, and hydroxyapatite. Fillers and polypropylene chips were combined and extruded into rods with the use of a mixer. The rods were chipped up and then formed into filaments through melt extrusion utilizing a piston extruder. Filaments with volume fractions of filler of 0.05, 0.10, 0.15, and 0.20 were produced. Additionally, some methods of trying to improve the properties of these filaments were attempted, but did not result in any significant property improvements. The fillers and filaments were visually characterized with a scanning electron microscope. Cross-sections, filament outer surfaces, fracture surfaces, and longitudinal cut open surfaces were viewed in this manner. Those filaments with anisotropic filler had some oriented filler particles, while all filaments suffered from poor adhesion between the polypropylene and the filler as well as agglomerations of filler particles. Twenty specimens of each filament were tensile tested and the average tenacity, strain, and modulus were calculated. Filaments containing talc, talc and wollastonite, titanium dioxide, or hydroxyapatite suffered from a drastic transition from ductile to brittle with the addition of 0.05 volume fraction of filler. This is evidenced by the sharp decrease in strain at this volume fraction of filler when compared to the strain of the unfilled polypropylene filament. Additionally, these same filaments suffered a sharp decrease in tenacity at the same volume fraction. These instant decreases are attributed to the agglomerations of filler in the filament. Generally, the modulus of the filaments increased with the increase in concentration of filler. The tensile tenacity, strain, and modulus were modeled with current composite models for particulate filled composites. The tenacity and strain models did not accurately predict the properties of the filaments, while the modulus models were more accurate, perhaps because the agglomerations of filler did not affect the modulus as much as it affected the tenacity and strain of the filaments. Production, characterization, and modeling of these filaments indicates that there are many areas for improvements, such as improved mixing of the filler and polypropylene, increased adhesion between matrix and filler, and decreased agglomerations of filler. Mechanically, these filaments can not match the properties of bone. However, they do have many structural similarities at the micro-mechanical level, so with some improvements in properties these filaments may be suitable models for modeling bone behavior.

George, Brian Robert

1999-11-01

79

The cell biology of suturing tendons.  

Science.gov (United States)

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 12h. Both tension and injury were required to induce cell death and cell movement in the formation of the acellular zone. DNA fragmentation studies and transmission electron microscopy indicated that cells necrosed. Parallel in vivo studies showed that cell-to-cell contacts were disrupted following grasping by the suture in tensioned tendon. Without tension, cell death was lessened and cell-to-cell contacts remained intact. Quantitative immunohistochemistry and 3D cellular profile mapping of wound healing markers over a one year time course showed that acellular zones arise rapidly and showed no evidence of healing whilst the wound healing response occurred in the surrounding tissues. The acellular zones were also evident in a standard modified "Kessler" clinical repair. In conclusion, the suture repair of injured tendons produces acellular zones, which may potentially cause early tendon failure. PMID:20600895

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

2010-07-01

80

Mechanical performance of gamma irradiated surgical sutures  

International Nuclear Information System (INIS)

Surgical sutures are medical devices made of natural or synthetic polymeric materials that, due to its end-use, have to be sterilized. Historically, the sterilization by heat or using ethylene oxide had presented so numerous drawbacks that today the non-pollutant radiation sterilization has become a well established sterilization process, that brings, environmental, technical, and economical advantages. The amount of irradiation doses required for sterilization of health care products is 25 kGy in most instances to achieve the necessary sterility assurance level. As high energy radiation produces modifications in the molecular structure of organic materials with changes in its mechanical properties, the aim of this work was to evaluate the mechanical behavior of surgical sutures under irradiation. Silk, polyamide and catgut sutures were gamma irradiated up to doses of 50 kGy in an industrial irradiation sterilization plant. Afterwards, these sutures were mechanical tested for tensile strength under knot following the specifications of the NBR13904 draft standard, using the CTRD-INSTRON at IPEN. The mechanical lab results show that sutures made of Silk and Polyamide do not present any change in their mechanical performance up to the dose of 50 kGy. On the other hand, Catgut present mechanical stability up to 30 kGy and afterwards, a slight decrease in its tensile strength was detected. (author)

2000-10-05

 
 
 
 
81

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

82

Cauterization technique for suture erosion in transscleralfixation of intraocular lenses  

Directory of Open Access Journals (Sweden)

Full Text Available Transscleral suturing is a commonly applied technique to fix intraocular implants in the sulcus. A major problem after transscleral implantation is suture erosion that normally happens in the late post-surgery period and may result in an increased incidence of endophthalmitis. Here we describe an original cauterization method by using a glass rod to melt the exposed suture end without damaging the suture knot in the sclera to avoid suture exposure in sclera-fixed IOL implantation. This is a simple, quick and effective technique that can be performed without conjunctiva incisions and will help to reduce suture erosion related complications.

Xu-Ting Hu

2013-12-01

83

Acute Airway Obstruction from a Suture Granuloma  

Directory of Open Access Journals (Sweden)

Full Text Available The complications of tracheotomy are routinely categorized from the time of operation to the onset of the complication and are thus divided into intraoperative, early, and late postoperative. A very common late complication is the development of granulation tissue. We describe a case of granulation tissue that formed around a retained silk suture obscuring about 40% of the lumen at exhalation and about 80% of the lumen with inspiration. The patient clinically experienced stridor, poor exercise tolerance, and difficulty in clearing tracheobronchial secretions. As a result, the patient required CO2 laser excision of the suture granuloma using a rigid ventilating bronchoscope and removal of the suture. We present an unusual but serious case of progressive airway obstruction.

Jawad Khan

2010-03-01

84

Laparoscopic fascial suture repair of parastomal hernia.  

Science.gov (United States)

Parastomal hernia is a recognised complication following stoma formation, representing a challenging problem to surgeons. At least three approaches for parastomal hernia repair have been described: fascial suture repair, relocation of stoma and local repair with use of mesh. In simple fascial suture repair only open techniques have been described. Relocation of stoma can be complicated with another parastomal hernia at the new site and risk of incisional hernia at the site of previous stoma. Mesh repair can be either open or laparoscopic. The recurrence rate and complications of parastomal hernia repair remain very high. We have invented a simple fascial suture laparoscopic repair of parastomal hernia with the use of the Crochet hook needle (EndoClose). This new technique may result in reduced pain, earlier discharge from hospital and reduced risk of infection as there is no mesh used as well as reduced risk of seroma formation. PMID:23780775

Zia, Khawaja; McGowan, David Ross; Moore, Etienne

2013-01-01

85

Low smoke polypropylene insulation compositions  

Energy Technology Data Exchange (ETDEWEB)

A flame retardant insulation composition is described comprising; (a) 5-40 percent by weight of a hydrogenated monoalkylarene (A)-conjugated diene (B) block copolymer containing at least one A block and at least one B block wherein at least 1 percent by weight of the block copolymer has been functionalized with a monomer that does not polymerize easily; (b) 1-20 percent by weight of a plasticizer; (c) 1-40 percent by weight of polypropylene; (d) 10-85 percent by weight of a hydrated magnesium hydroxide which has been surface treated with a coupling agent.

Djinauw, L.K.; Icenogle, R.D.

1988-12-27

86

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

87

Single interrupted sutures compared with Donati sutures after open carpal tunnel release: a prospective randomised trial.  

Science.gov (United States)

Inversion of the wound edges is one of the potential causes of postoperative scar tenderness after open carpal tunnel release. When using vertical mattress sutures (also named Donati sutures), inversion of wound edges is less likely to occur compared with single interrupted sutures. The purpose of this study was to compare the use of both sutures after open carpal tunnel release and assess their effects on scar tenderness and functional outcome. A prospective randomised controlled trial was performed comparing single interrupted and Donati sutures. Eighty-nine hands were included in the study. Eight weeks postoperatively, scar formation was nice/very nice in 94% (single stitches) and 97% (Donati stitches) of the patients. Pain and disability scores were, in both groups, improved 8 weeks postoperatively, although the patients receiving Donati sutures had a 2-fold higher pain score. In conclusion, both Donati and single stitches are related to excellent scar formation. The Donati sutures are related to more prolonged postoperative pain. PMID:23710789

Bolster, Mireille; Schipper, Carlijn; Van Sterkenburg, Steven; Ruettermann, Mike; Reijnen, Michel

2013-09-01

88

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

89

Smad7 modulates TGF? signaling during cranial suture development to maintain suture patency.  

Science.gov (United States)

Craniosynostosis, the premature fusion of one or more sutures between the calvarial bones, is a common birth defect. Mutations in genes encoding receptors for the transforming growth factor-beta (TGF?) family of signaling molecules have been associated with craniosynostosis, but how TGF? signaling is regulated during suture development is not known. In the present study, we found that expression of Smad2 and Smad3, intracellular mediators of canonical TGF? signaling, gradually increases during early postnatal suture development in rat in both the coronal suture (CS), which remains patent throughout life, and the posterior frontal suture (PFS), which undergoes programmed closure by postnatal day 22. The amounts of phosphorylated Smad2 and Smad3 proteins showed a similar gradual increase in the PFS and CS, but in the CS, Smad2/3 activation was suppressed after neonatal day 10. The suppression of Smad2/3 activation in the CS correlated with upregulation of Smad7 expression. We demonstrate that siRNA-mediated knockdown of Smad7 caused increased phosphorylation of Smad2 and Smad3 and induced osseous obliteration of the CS from postnatal days 10 to 22. The Smad7 siRNA-induced CS closure was associated with significantly increased levels of Fgf10 and phosphorylated ERK1/2 in the suture mesenchyme. Moreover, addition of the Erk1/2 inhibitor U0126 partially blocked Smad7-siRNA-induced CS closure. These findings suggest that canonical TGF? signaling induces suture closure at least in part through activation of FGF and ERK signaling and that Smad7 plays an important role in maintaining suture patency by suppressing canonical TGF? signaling during suture development. PMID:23959527

Zhou, Hao; Zou, Shujuan; Lan, Yu; Fei, Wei; Jiang, Rulang; Hu, Jing

2014-03-01

90

Joining and gluing sutured Floer homology  

CERN Document Server

We give a partial characterization of bordered Floer homology in terms of sutured Floer homology. The bordered algebra and modules are direct sums of certain sutured Floer complexes. The algebra multiplication and algebra action correspond to a new gluing map on SFH. It is defined algebraically, and is a special case of a more general "join" map. In a follow-up paper we show that this gluing map can be identified with the contact cobordism map of Honda-Kazez-Matic. The join map is conjecturally equivalent to the cobordism maps on SFH defined by Juhasz.

Zarev, Rumen

2010-01-01

91

Sutured Floer homology distinguishes between Seifert surfaces  

CERN Document Server

In this note we exhibit the first example of a knot in the three-sphere with a pair of minimal genus Seifert surfaces that can be distinguished using the sutured Floer homology of their complementary manifolds together with the Spin^c-grading. This answers a question of Juh\\'asz. More precisely, we show that the Euler characteristic of the sutured Floer homology of the complementary manifolds distinguishes between the two surfaces, and we exhibit an infinite family of knots with pairs of Seifert surfaces that can be distinguished in such a way.

Altman, Irida

2010-01-01

92

Postmortem analysis of anastomotic suture line disruption following carotid endarterectomy.  

Science.gov (United States)

The tensile strength of a surgical suture is essential in maintaining the integrity of vascular anastomoses. While faulty operative technique and the loading strength of individual sutures have been implicated in spontaneous suture line disruptions, there has, to date, never been a published postmortem analysis of a suture that has known to have failed. We present the case of suture line disruption leading to fatal exsanguination in a 77-year-old man following carotid endarterectomy with a facial vein patch. Using both dissecting and scanning electron microscopy, we determined that surgical technique (an untied knot) was the cause of the suture line disruption. The removal of a broken or untied suture at surgery or at autopsy should not preclude proper analysis of the failed suture, because the results can have both medico-legal and public health implications. PMID:15461114

Melinek, Judy; Lento, Patrick; Moalli, John

2004-09-01

93

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

Science.gov (United States)

...made of polypropylene, polyethylene terephthalate, or polytetrafluoroethylene...made of polypropylene, polyethylene terephthalate, or polytetrafluoroethylene...made of polypropylene, polyethylene terephthalate, or...

2010-04-01

94

Horizontal Running Mattress Suture Modified with Intermittent Simple Loops  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

95

In Vivo Strain in Cranial Sutures: The Zygomatic Arch  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Although cranial sutures presumably play a role in absorbing and/or transmitting loads applied to the skull, loading patterns on facial sutures are poorly understood. The zygomatic arch provides a comparatively isolated mechanical part of the skull containing a single suture, the zygomatico-squamosal. In pigs the zygomatico-squamosal suture has a short vertical segment located within the postorbital process and a longer horizontal segment which extends posteriorly. In anesthetized pigs single...

Herring, Susan W.; Mucci, Robert J.

1991-01-01

96

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

97

A modified suture technique produces consistent cerebral infarction in rats  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Intraluminal occlusion of the middle cerebral artery (MCA) is used extensively in cerebral ischemia research. We tested a modified nylon suture in a rat model of middle cerebral artery occlusion (MCAO) under two anesthesia regimens. Sprague-Dawley rats were divided into six groups (Group 1, Poly-L-lysine-coated suture under ketamine/xylazine anesthesia; Group 2, modified suture under ketamine/xylazine anesthesia; Group 3, Poly-L-lysine-coated suture under ketamine/xylazine anesthesia with mec...

Zhao, Honggang; Mayhan, William G.; Sun, Hong

2008-01-01

98

Simple suture and anchor in rabbit hips  

Science.gov (United States)

Objective Using biomechanical studies, this research aims to compare hip capsulorrhaphy in rabbits, carried out with two different techniques: capsulorrhaphy with simple sutures and with anchors. Method Thirteen New Zealand Albino (Oryctolaguscuniculus) male rabbits, twenty-six hip joints, were used. First, a pilot project was performed with three rabbits (six hip joints). This experiment consisted of ten rabbits divided into two groups: group 1 underwent capsulorrhaphy on both right and left hips with simple suture using polyglycolic acid absorbable thread, and group 2 underwent capsulorrhaphy with titanium anchors. After a four-week postoperative period, the animals were euthanized and the hip joints were frozen. On the same day of the biomechanical studies, after the hip joints were previously unfrozen, the following parameters were evaluated: rigidity, maximum force, maximum deformity and energy. Results There was no relevant statistical difference in rigidity, maximum force, maximum deformity and energy between the simple suture and anchor groups. Conclusion Through biomechanical analyses, using parameters of rigidity, maximum force, maximum deformity and energy, it has been shown that capsulorrhaphy with simple suture and with anchors has similar results in rabbit hip joints. Level of Evidence II, Prospective Comparative Study.

Garcia Filho, Fernando Cal; Guarniero, Roberto; de Godoy Junior, Rui Maciel; Pereira, Cesar Augusto Martins; Matos, Marcos Almeida; Garcia, Lucas Cortizo

2012-01-01

99

Aortic valve annuloplasty: new single suture technique.  

Science.gov (United States)

Reconstruction strategies for aortic valve insufficiency in the presence of aortic annulus dilatation are usually surgically challenging. We demonstrate a simple, modified Taylor technique of downsizing and stabilization of the aortic annulus using a single internal base suture. Since April 2011, 22 consecutive patients have undergone safe aortic valve annuloplasty. No reoperations for aortic valve insufficiency and no deaths occurred. PMID:24882316

Schöllhorn, Joachim; Rylski, Bartosz; Beyersdorf, Friedhelm

2014-06-01

100

Effectiveness of glycomer 631 monofilament sutures in closing musculoaponeurotic incisions.  

Science.gov (United States)

The purpose of this study was to quantitate the effect of two monofilament synthetic absorbable sutures as well as a new monofilament synthetic absorbable suture, glycomer 631, in healing musculoaponeurotic incisions in rats. Because these three monofilament synthetic absorbable sutures provided secure closure of laparotomy incisions, their clinical use in laparotomy incisions is recommended. PMID:10186968

Rodeheaver, G T; Salopek, L S; Green, C W; Foresman, P A; Suber, F; Neal, J G; Edlich, R F

1998-01-01

 
 
 
 
101

High temperature behavior of polypropylene and polypropylene / glass composites  

Science.gov (United States)

Solid state die drawing of polymer matrix composite materials offers an opportunity to make products that cannot be produced by any other method. This is done by heating a composite billet to a temperature just below the melting point and drawing it through a heated converging die by pulling from the downstream side. Since this is done at high temperatures, it is imperative to understand the behavior of the polymer and the composites at high temperature. Therefore, in this work, the stress-strain behavior of neat polypropylene and polypropylene composites with glass flake and glass bead fillers was studied at 23°C, 130°C, and 145°C. The onset of debonding was found to occur at a lower stress and strain for the composites tested at higher temperature, while the loss of reinforcement was slower at the elevated temperatures. The interfacial interaction between the filler and matrix was also determined to be greater at elevated temperatures. The presence of filler particles also changed the character of the stress-strain curves at higher temperatures. Specifically, the filler induced a sharper neck region in the composites at elevated temperature. Annealing for one hour at temperatures between 130°C and 145°C produced a secondary, lower melting temperature peak in the DSC curves, which increased in prominence with increasing temperature. This increase in prominence was greater for the composites than for the neat polymer. Finally, the onset of debonding was studied using transverse strain vs. stress curves for the two composites. The debonding stress decreased with increasing temperature for both materials, and it was determined that stress amplification at the interface is greater for the flake composite than for the bead composite.

Shipley, Katherine Mary Herber

102

Advances in the radiation stabilization of polypropylene  

International Nuclear Information System (INIS)

The addition of mobilizing additives to polypropylene increases the rate of radical termination as measured by ESR. The reduced radical population reduces the extent of polymer oxidation and improves the mechanical properties of the polymer. (author)

1983-01-01

103

Advances in the radiation stabilization of polypropylene  

Energy Technology Data Exchange (ETDEWEB)

The addition of mobilizing additives to polypropylene increases the rate of radical termination as measured by ESR. The reduced radical population reduces the extent of polymer oxidation and improves the mechanical properties of the polymer.

Williams, J.L.; Dunn, T.S. (Becton Dickinson Research Center, Research Triangle Park, NC (USA))

1983-01-01

104

Vibrational overtone in crystalline isotactic polypropylene  

Energy Technology Data Exchange (ETDEWEB)

Crystalline isotactic polypropylene is subjected to high but non-hydrostatic pressures and the Raman Spectra analyzed. There is evidence that the band at 2725 cm/sup -1/ is an overtone of the 1376 cm/sup -1/ band.

Ize-Iyamu, M.I.

1983-01-01

105

Polypropylene Fibers in Portland Cement Concrete Pavements.  

Science.gov (United States)

This report provides the information obtained from a literature search, site visits, and a laboratory study of polypropylene fibers in portland cement concrete (PCC). The literature search yielded information from numerous laboratory studies of the materi...

J. E. Shoenberger J. G. Tom

1992-01-01

106

Infrared spectroscopic study of irradiated polypropylene.  

Science.gov (United States)

The growth absorbency of carbonyl and carboxyl groups was used to study the effect of radiation stabilizer and improving the properties of the irradiated of polypropylene using IR spectroscopy. the result indicates that the linearity of absorbency depends...

M. Al-Ibrahim H. Al-Kassiri

1996-01-01

107

Conductive polypropylene composites; Przewodzace kompozyty polipropylenu  

Energy Technology Data Exchange (ETDEWEB)

The results of studies on polypropylene composites with three sorts of Polish-made carbon blacks were presented. It was found that composite of 20% black content had properties of an electrically conducting material. 8 refs, 5 figs, 7 tabs.

Koszkul, J. [Politechnika Czestochowska, Czestochowa (Poland)

1997-12-31

108

Evaluation of Bituminous Pavement with Polypropylene Fiber.  

Science.gov (United States)

This study was conducted to evaluate the performance of a hot mix asphalt overlay modified with polypropylene fiber. In 1986, a continuously reinforced concrete pavement on Interstate 69 in Meridian, MS, was overlaid with hot mix asphalt binder and surfac...

M. Seshadri

1996-01-01

109

Ppx - a New Dyeable Polypropylene Fiber.  

Science.gov (United States)

A laboratory dyeability evaluation of a new dyeable polypropylene fiber was made to determine its potential for military and civilian textile use. Disperse and premetallized dyes are applied by a simultaneous scouring and dyeing process. Disperse dyeings ...

J. J. Press

1966-01-01

110

Highly Filled Polypropylene Rubber Wood Flour Composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Sarawut Rimdusit; Watanachai Smittakorn; Saroj Jittarom; Sunan Tiptipakorn

2011-01-01

111

[Paleopathologic findings of premature coronal suture closure].  

Science.gov (United States)

The work describes paleopathologic finding of brachycephaly deformation in 4 adult skulls, caused by premature coronal suture closure. Skulls come from the 35 pieces collection of craniostenoses, found in osteologic collection of 745 skulls from Broumov Ossuary. They were examined by cranioscopy, craniometry, x-ray and CT methods. Presence of brachycephaly in Broumov collection of skulls ant their percentage in the collection of craniosynostoses is discussed in the context with recent clinical data. PMID:19569587

Pospísilová, Blanka; Procházková, Olga; Serbouti, Khalid

2003-01-01

112

Comparison of colorectal mechanical suture techniques  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Objective of this study is to establish which kind of stapled anastomosis is the most reliable in rectal surgery. 67 patients randomly assigned to three groups underwent low anterior resection of the rectum with end-to-end, side-to-end or double stapling anastomosis. Main outcome measures were incidence of leakage at the intraoperative check of the suture, postoperative leakage, stenosis, mortality, mean post-operative stay. Side-to-end anastomosis were followed by 4 intra-operative (19%) and...

Arezzo, Alberto

1997-01-01

113

High coverage of hydrogen on a (10,0) single-walled boron nitride nanotube  

Science.gov (United States)

The binding energy of hydrogen atoms to a (10,0) single-walled boron nitride nanotube (SWBNNT) is calculated at 25%, 50%, 75%, and 100% coverage using the density functional theory. The average binding energy is highest at 50% coverage when the H atoms are adsorbed on the adjacent B and N atoms along the tube axis and the value is -53.93kcal/mol , which is similar to half of the H?H binding energy. Also, the band gap (-4.29eV) of the pristine (10,0) SWBNNT is decreased up to -2.01eV for the H-adsorbed BNNT with 50% coverage.

Han, Sang Soo; Lee, Sung Hoon; Kang, Jeung Ku; Lee, Hyuck Mo

2005-09-01

114

The use of imbricated sutures in radioactive plaque brachytherapy surgery  

Directory of Open Access Journals (Sweden)

Full Text Available Kaan Gündüz1, Jose S Pulido1, Peter D Yeakel2, Michael King3, Kelly L Classic1, Keith M Furutani21Department of Ophthalmology, 2Department of Radiation Oncology, 3Section of Media Support Services, Mayo Clinic, Rochester, MN, USAAbstract: This paper describes a new technique to suture the radioactive plaque to sclera. The radioactive plaque is conventionally sutured to the sclera using 5/0 nylon sutures. The imbricated suture technique involves using a 1/0 silk or 2/0 mersilene suture imbricated with the 5/0 nylon suture when the nylon suture is tied and cut. The imbricated suture technique allows easy identification of the plaque at removal and provides a surface that separates the 5/0 nylon from the surface of the eyelet platform, making suture cutting easier and safer. The radiation exposure times ranged from 9.1 minutes to 14 minutes (mean: 10.8 minutes during plaque insertion and from 2.8 to 3.3 minutes (mean: 3.0 minutes during plaque removal with the imbricated suture technique. This technique may decrease radiation exposure time and may prevent inadvertent scleral damage.Keywords: plaque radiotherapy, Iodine-125, Ruthenium-106, Collaborative Ocular Melanoma Study, choroidal melanoma, ciliary body melanoma, retinoblastoma, plaque placement, plaque removal, radiation exposure

Kaan Gündüz

2010-03-01

115

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.

2012-09-01

116

Polypropylene nanogel: “Myth or reality”  

Science.gov (United States)

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.

Oliani, W. L.; Parra, D. F.; Riella, H. G.; Lima, L. F. C. P.; Lugao, A. B.

2012-09-01

117

Polypropylene nanogel 'myth or reality'  

International Nuclear Information System (INIS)

Complete text of publication follows. The objective of this work is to study the formation of nanogel and microgel 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 12.5 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 deg C, followed by decantation in becker at room temperature of 25 deg C with the total volatilization of the xylene and deposition of dried material film on fine glass blades under agitation by Settling process. The thin film gel formed of pristine PP and modified (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 12.5 kGy. Acknowledgement. The authors thank FAPESP, CAPES for grants, CCTM/IPEN, for microscopy analysis SEM, Eleosmar Gasparin for DSC analysis and Embrarad/CBE for irradiating the samples.

2011-09-01

118

Argon plasma irradiation of polypropylene  

International Nuclear Information System (INIS)

Polypropylene samples were exposed to argon plasma discharge and the changes of the PP surface properties were studied by different methods. Surface wettability was derived from contact angle measured by standard goniometry and chemical structure of the plasma modified PP was studied using X-ray photoelectron spectroscopy (XPS) and by Rutherford backscattering spectroscopy (RBS), surface morphology and roughness of samples using AFM. Zeta potential of pristine and modified PP was determined with the SurPASS. The presence of incorporated oxygen in the PP surface layer, about 60 nm thick, was observed in RBS spectra. Oxygen concentration is a decreasing function of the depth. With progressing aging time the oxygen concentration on the PP surface decreases. Plasma treatment results in a rapid decrease of the contact angle, which increases again with increasing aging time. In XPS measurement the oxygen containing structures, created by the plasma treatment, were found on the very surface of the modified PP and the zeta potential being changed too. The significant difference in zeta potential between pristine and plasma treated PP clearly indicates that the plasma treatment leads to a more hydrophilic PP surface.

2010-06-01

119

Aksa plans polypropylene joint venture  

Energy Technology Data Exchange (ETDEWEB)

Turkish acrylic fiber maker Aksa (Yalova), part of the Akkok textile conglomerate, is studying construction of a world-scale polypropylene (PP) plant as part of its diversification plans. The company says it is engaged in discussions with three multinations in the PP business' on the possibility of a joint venture. One of the firms is understood to be Amoco. Aksa is looking at three possible locations for the 100,000 m.t.-150,000 m.t./year plant: Yalova, near Istanbul, where its existing plants are located; Zonguldak, on the Black Sea coast; and within one of the existing complexes or a new site belonging to state-owned Petkim. Aksa has not yet discussed that option with Petkim, which recently received approval to build a $2.5-billion petrochemical complex. The Aksa PP plant would cost about $100 million and would use propylene from world markets. The onstream date depends on Aksa's ability to link up with a foreign partner, but it hopes to complete the unit within three years. Turkey has only one PP plant, a 65,000-m.t./year Petkim unit at Aliaga. The domestic market is currently two to three times that amount and is growing. Petkim also plans a 200,000-m.t./year PP plant as part of its new complex.

Alperowicz, N.

1992-12-02

120

Aksa plans polypropylene joint venture  

International Nuclear Information System (INIS)

Turkish acrylic fiber maker Aksa (Yalova), part of the Akkok textile conglomerate, is studying construction of a world-scale polypropylene (PP) plant as part of its diversification plans. The company says it is engaged in discussions with three 'multinations in the PP business' on the possibility of a joint venture. One of the firms is understood to be Amoco. Aksa is looking at three possible locations for the 100,000 m.t.-150,000 m.t./year plant: Yalova, near Istanbul, where its existing plants are located; Zonguldak, on the Black Sea coast; and within one of the existing complexes or a new site belonging to state-owned Petkim. Aksa has not yet discussed that option with Petkim, which recently received approval to build a $2.5-billion petrochemical complex. The Aksa PP plant would cost about $100 million and would use propylene from world markets. The onstream date depends on Aksa's ability to link up with a foreign partner, but it hopes to complete the unit within three years. Turkey has only one PP plant, a 65,000-m.t./year Petkim unit at Aliaga. The domestic market is currently two to three times that amount and is growing. Petkim also plans a 200,000-m.t./year PP plant as part of its new complex

1992-12-02

 
 
 
 
121

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)

1982-01-01

122

Polypropylene-based composites reinforced by toluene diisocyanate modified wood  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Composites made of polypropylene, a mixture of polypropylene and poly(lactic acid) and spruce wood fibres both non-modified and modified with toluene 2,4-diisocyanate - were prepared by melt blending. The chemical modifications of wood fibres with toluene 2,4-diisocyanate were evidenced by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Wood fibre reinforced polypropylene/poly(lactic acid) composites prepared with addition of maleic anhydride polypropylene as cou...

2013-01-01

123

Effect of Braiding and Hot Stretching Conditions on Sutures Performances  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The success of wound healing depends on suture performances, such as slippage ratio, deformation recovery, knot performance and tensile properties. The main objective of this study is to determine the effect of manufacturing parameters related to braiding and hot stretching steps on suture performances. Obtained results showed that hot stretching contributes to macromolecular chains arrangement as well as suture performances and structural properties improving. The percentage of crystallinity...

Faten Debbabi; Saber Ben Abdessalem

2011-01-01

124

MATERIAL PROPERTIES OF COMMON SUTURE MATERIALS IN ORTHOPAEDIC SURGERY  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Suture materials in orthopaedic surgery are used for closure of wounds, repair of fascia, muscles, tendons, ligaments, joint capsules, and cerclage or tension band of certain fractures. The purpose of this study was to compare the biomechanical properties of eleven commonly used sutures in orthopaedic surgery. Three types of braided non-absorbable and one type of braided absorbable suture material with different calibers (n=77) underwent biomechanical testing for maximum load to failure, stra...

Najibi, S.; Banglmeier, R.; Matta, Jm; Tannast, M.

2010-01-01

125

Tissue reactions to modern suturing material in colorectal surgery.  

Science.gov (United States)

Morphological changes in the wall of the large intestine were studied after its manual suturing by a double-row interrupted suture with modern suture threads. Light and scanning electron microscopy showed "fuse properties" and "sawing effect" of polyfilament twisted threads (e.g. vicryl). Monofilament threads were free from these drawbacks and therefore were preferable. Metal elastic threads on the basis of titanium-nickelide alloys caused no inflammatory changes in tissues. PMID:18239823

Molokova, O A; Kecherukov, A I; Aliev, F Sh; Chernov, I A; Bychkov, V G; Kononov, V P

2007-06-01

126

Radioactive suture in the treatment of head and neck cancer  

Energy Technology Data Exchange (ETDEWEB)

/sup 125/I seeds in Vicryl suture have been used as a radioactive suture in 24 cases of advanced malignancy of the head and neck. Twelve cases had metastatic carcinoma attached to the internal or common carotid artery. The goal was to excise surgically as much tumor as possible, then implant any residual tumor with this radioactive suture which remains as a permanent implant (half-life of 60 days). This preliminary study shows that use of /sup 125/I impregnated Vicryl suture in this manner appears to produce improved long-term palliation and may increase local cure rates.

Goode, R.L.; Fee, W. Jr.; Goffinet, D.; Martinez, A.

1979-03-01

127

Visual measurement of suture strain for robotic surgery.  

Science.gov (United States)

Minimally invasive surgical procedures offer advantages of smaller incisions, decreased hospital length of stay, and rapid postoperative recovery to the patient. Surgical robots improve access and visualization intraoperatively and have expanded the indications for minimally invasive procedures. A limitation of the DaVinci surgical robot is a lack of sensory feedback to the operative surgeon. Experienced robotic surgeons use visual interpretation of tissue and suture deformation as a surrogate for tactile feedback. A difficulty encountered during robotic surgery is maintaining adequate suture tension while tying knots or following a running anastomotic suture. Displaying suture strain in real time has potential to decrease the learning curve and improve the performance and safety of robotic surgical procedures. Conventional strain measurement methods involve installation of complex sensors on the robotic instruments. This paper presents a noninvasive video processing-based method to determine strain in surgical sutures. The method accurately calculates strain in suture by processing video from the existing surgical camera, making implementation uncomplicated. The video analysis method was developed and validated using video of suture strain standards on a servohydraulic testing system. The video-based suture strain algorithm is shown capable of measuring suture strains of 0.2% with subpixel resolution and proven reliability under various conditions. PMID:21436874

Martell, John; Elmer, Thomas; Gopalsami, Nachappa; Park, Young Soo

2011-01-01

128

The use of imbricated sutures in radioactive plaque brachytherapy surgery  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Kaan Gündüz1, Jose S Pulido1, Peter D Yeakel2, Michael King3, Kelly L Classic1, Keith M Furutani21Department of Ophthalmology, 2Department of Radiation Oncology, 3Section of Media Support Services, Mayo Clinic, Rochester, MN, USAAbstract: This paper describes a new technique to suture the radioactive plaque to sclera. The radioactive plaque is conventionally sutured to the sclera using 5/0 nylon sutures. The imbricated suture technique involves using a 1/0 silk or 2/0 mersilene sutu...

2010-01-01

129

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

2007-07-01

130

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

131

Permeation of tritiated water through polypropylene  

International Nuclear Information System (INIS)

The permeability of water through the polypropylene film was studied using tritiated water. Experiments were carried out in a flow type vessel designed for the determination of the permeability of water. All permeated water was captured by a water bubbler. The permeability was evaluated from the amount of tritiated water permeated through the polymer. The obtained apparent permeability increased with increasing temperature. The temperature dependence was governed by the water vapor pressure. The permeability of water through polypropylene normalized by water vapor pressure was found to be 1.9x10-13 g cm cm-2s-1 Torr-1 at 296 K. (author)

2010-12-01

132

Internal friction studies of particulate filled polypropylene  

International Nuclear Information System (INIS)

Internal friction of injection-molded polypropylene with various fractions of magnetite, barite, copper, talc, strontium ferrite and glass fibers was measured in the temperature range 170-425 K with frequencies of 0.1-100 Hz. Peaks of the ?- and ?'-relaxation were found while no peak of the ?-relaxation was detected. At high temperatures a drastic increase of the loss factor superposes the ?'-peak. The crystallinity of the filled polypropylene varies in the range from 23% to 35%. The samples consist of ?- and ?-crystallites depending on the material and amount of filler

2006-12-20

133

Organobentonite / Polypropylene Nanocomposite for Packaging Application  

Science.gov (United States)

Na-bentonite was treated with several kind of quaternary alkyl ammonium cation by ion exchange reaction to find the high efficiency one to exfoliate the longer of nanoclay. DOEM exhibited the good performance to continue the work. The organomodified bentonite was compounded with polypropylene by using Surlyn^ ionomer as a compatibilizer to produce the packaging film. In addition the organobentonite was modified by ethylene scavenger chemical and characterized by XRD and FT-IR. It was compound with polypropylene to prepare the active packaging film.The gas permeability, ethylene adsorption-desorption, thermal and mechanical properties were investigated.

Varothai, Yukhanthorn; Phandee, Atinuch; Nithitanakul, Manit; Magaraphan, Rathanawan; Manuspiya, Hathaikarn

2007-03-01

134

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

1996-01-01

135

Polypropylene mesh repair of incisional hernia  

International Nuclear Information System (INIS)

Objective: The purpose of this study is to report the results of tension-free repair of primary and recurrent incisional hernias using polypropylene (Prolene) mesh. Results: The mean age was 43.7 years. The only death occurred in a known cirrhotic presenting with obstructed hernia. Another patient was seen developing seroma and wound infection in one case. No recurrence was seen during the mean follow-up period of 2.2 years. Conclusion: the tension-free repair of incisional hernia, with polypropylene mesh in extra facial position, is safe and easy procedure with acceptable morbidity and no recurrence. (author)

2003-08-01

136

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

137

Effect of electron beam radiation on the polypropylene/polyethylene blends: Radiation stabilization of polypropylene  

International Nuclear Information System (INIS)

The effect of incorporation of polyethylene in the polypropylene matrix, on the radiation sensitivity of polypropylene, has been investigated. The changes in the properties such as tensile strength, elongation at break, Shore D hardness, density and melt flow index were monitored as function of polyethylene content and electron beam radiation dose. A correlation between the mechanical properties and morphology of the irradiated polymeric blends has been observed, which has been explained on the basis of Fourier-transform infrared spectroscopy, scanning electron microscope and X-ray diffraction studies. Improvement in the mechanical properties of the polypropylene, irradiated to an optimum electron beam dose, could be achieved by blending it with polyethylene >20%. The optimum radiation dose was found to be dependent on blend composition and morphology, however, an absorbed dose of 250 kGy found to be effective enough to ensure good mechanical properties of the polypropylene/polyethylene blends

2007-10-01

138

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2011-01-01

139

Sidewinder retention sutures for closure of the abdominal wall.  

Science.gov (United States)

Reported herein, a technique of sutures placement that avoids certain objections to the traditional style of retention sutures is described. It is particularly useful in patients undergoing repeated laparotomy and in patients whose wounds are closed in a layered manner and who are at high risk for dehiscence. PMID:2525819

Rappaport, W D; Putnam, C

1989-07-01

140

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.)

1998-02-01

 
 
 
 
141

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

142

Nose tip refinement using interdomal suture in caucasian nose  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Refinement of the nose tip can be accomplished by a variety of techniques, but currently, the use of sutures in the nasal tip with conservative resection of the alar cartilage is the most frequently recommended approach. Objective: To classify the nasal tip and to demonstrate the interdomal suture applied to nasal tip refinement in the Caucasian nose, as well as to provide a simple and practical presentation of the surgical steps. Method: Development of surgical algorithm for nasal tip surgery: 1. Interdomal suture (double binding suture, 2. Interdomal suture with alar cartilage weakening (cross-hatching, 3. Interdomal suture with cephalic removal of the alar cartilage (McIndoe technique based on the nasal tip type classification. This classification assesses the interdomal distance (angle of domal divergence and intercrural distance, domal arch width, cartilage consistency, and skin type. Interdomal suture is performed through endonasal rhinoplasty by basic technique without delivery (Converse-Diamond technique under local anesthesia Conclusion: This classification is simple and facilitates the approach of surgical treatment of the nasal tip through interdomal suture, systematizing and standardizing surgical maneuvers for better refinement of the Caucasian nose.

Pasinato, Rogério

2012-01-01

143

The postnatal development of the human maxillary sutural surfaces  

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The results of several studies indicate that the response of facial bones to forces applied to maxillary teeth, as is done in dentofacial orthopedics, may be related to the morphology and the spatial topography of sutural surfaces. Studies published previously have described limited aspects of only a few human circummaxillary sutures. ... Zie: Summary

Remmelink, Hendrik Jan

1985-01-01

144

Biomechanical evaluation of tibial eminence fractures using suture fixation.  

Science.gov (United States)

This study evaluates the initial fixation strength of tibial eminence fracture repair using 1, 2, 3, and 4 sutures to determine the optimal number of sutures required to adequately secure the avulsed fragment to the tibia. Sixteen skeletally immature porcine knees were stripped of all soft tissues, isolating the femur-anterior cruciate ligament (ACL)-tibia complex. Type III tibial eminence fractures were simulated in the specimens, and each specimen was randomly assigned to a repair group using 1, 2, 3, or 4 #2 FiberWire sutures (Arthrex, Inc, Naples, Florida). Initial fixation strength of the repair was measured by single cycle pull to failure testing using a materials testing machine (Instron, Norwood, Massachusetts). The mean ultimate failure force during anterior tibial translation was 389±128, 627±66, 703±77, and 802±29 N for 1, 2, 3, and 4 sutures, respectively. The lower limit of the 95% confidence interval was >500 N (estimated force of native ACL during activities of daily living) for each group with ?2 sutures. In this study, at least 2 high-strength sutures were needed for tibial eminence fracture repairs to withstand potential forces seen across the ACL in the postoperative period. Suture fixation of tibial eminence fractures is a reproducible method requiring a minimum of 2 high-strength polyester sutures to resist forces seen during early rehabilitation. PMID:22146203

Aoki, Stephen K; Curtis, Stuart H

2011-12-01

145

Toxicity of pyrolysis gases from polypropylene  

Science.gov (United States)

A sample of polypropylene was evaluated for toxicity of pyrolysis gases, using the toxicity screening test method developed at the University of San Francisco. The gases from this sample appeared to be equivalent or less toxic than the gases from a sample of polyethylene under these particular test conditions. Carbon monoxide appeared to be the principal toxicant.

Hilado, C. J.; Schneider, J. E.; Brauer, D. F.

1979-01-01

146

Floor heating tubes made of polypropylene  

Energy Technology Data Exchange (ETDEWEB)

Possible causes of damage in polypropylene tubes in heating systems are listed. However, it should be stated that damage need not be expected if all regulations concerning the planning production, fabrication, storage, handling, assembly, operation and use of such systems are observed.

Dworski, K.

1980-01-01

147

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

148

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 SciELO Chile | Language: Spanish Abstract in spanish 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.

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

149

Effect of Braiding and Hot Stretching Conditions on Sutures Performances  

Directory of Open Access Journals (Sweden)

Full Text Available The success of wound healing depends on suture performances, such as slippage ratio, deformation recovery, knot performance and tensile properties. The main objective of this study is to determine the effect of manufacturing parameters related to braiding and hot stretching steps on suture performances. Obtained results showed that hot stretching contributes to macromolecular chains arrangement as well as suture performances and structural properties improving. The percentage of crystallinity of fabricated suture was ameliorated by hot stretching suture and reaches 25.51% under temperature of 170C and during 3 min. An increase of hot stretching load to 15 N reduces slippage ratio and improves percentage of deformation recovery as a consequence of the improving of macromolecular chains arrangement.

Faten Debbabi

2011-01-01

150

The effect of two nonresorbable suture types on the mechanical performance over a metal suture anchor eyelet.  

Science.gov (United States)

An understanding of the mechanical properties of different suture materials is valuable when selecting the most appropriate suture and repair technique. Sutures should be strong, easy to handle and have high knot security. The introduction of suture anchors adds an additional variable regarding the effect of stress risers over the eyelet. Improving the mechanical properties of a suture may be a possible method to help avoid failure over stress risers such as the eyelet of suture anchor. This study examined the static and viscoelastic properties of a new polyethylene based non-resorbable suture (Fibrewire) over the eyelet of a standard anchor compared to braid polyester non-resorbable suture (Ethibond). Fibrewire had superior ultimate load properties compared to Ethibond (360.2 N+/-23.8 vs 191.9 N+/-17.3) as well as greater stiffness (61.3 N/mm+/-9.7 vs 8.1 N/mm+/-0.4) when tested in uniaxial tension through a metal anchor eyelet (Mitek) ( psuture may have implications in the post-operative period or during rehabilitation. PMID:13680105

Acton, D; Perry, A; Evans, R; Butler, A; Stephens, P; Bruce, W; Goldberg, J; Sonnabend, D; Walsh, W R

2004-03-01

151

Meso-Tethyan oceanic sutures and their deformation  

Science.gov (United States)

On the basis of comparative stratigraphie and paleontologic analysis, supported by some key paleomagnetic data and interpretations, it is shown that during the Mesozoic and the Cenozoic the Eurasian continent grew by accretion of microcontinents. These microcontinents separated basins with oceanic crust from the main ocean. During the Late Cretaceous and the early Cenozoic the collision of the microcontinents with Eurasia resulted in the closure of the basins, and Meso-Tethyan oceanic sutures originated. In the region under consideration, from the Carpathians to Tibet, there are two main Meso-Tethyan sutures: the Carpathian-Lesser Caucasus and the Afghan-Tibet suture. The above-mentioned main structures also had branches, which remained as sutures of small basins: the Kamennopotock, Interpontide, Nain-Baft basins and others. In the West Carpathians the Carpathian-Lesser Caucasus suture is overlain by a widespread Gemeric-Tatric allochton. From the West Carpathians the suture passes through the Pannonian basin into the Vardar ophiolite zone and farther to the ophiolites of the Izmir-Ankara zone. Being displaced along the North Anatolian right-lateral strike-slip fault, the main suture passes from the Eastern Pontides into the Lesser Caucasus, where it is marked by ophiolites of the Amasia area, the Shirak, Bozum and Zangezur ridges. Sunsequently, it can be observed through the Iranian Qara Dagh mountains to Lake Urumiyeh and the North Anatolian strike-slip fault. Being again shifted along the strike-slip fault, the Carpathian-Lesser Caucasus Meso-Tethyan suture ends in the Western Zagros near the Cenozoic Neo-Tethyan suture. The Afghan-Tibet Meso-Tethyan suture is situated in the Pamirs in the Rushan-Pshart zone. The east prolongation of the suture has been displaced along the Pamir-Karakorum right-lateral strike-slip fault in Tibet. West of the Pamirs this suture is also displaced along strike-slip faults and continues in the Farahrud zone in Afghanistan, and than passes through the Zabol-Baluch and Daz Murian ophiolite zones and approaches the Neo-Tethyan suture. The paleomagnetic data allow us to reconstruct the location of those sutures in the Late Cretaceous-early Cenozoic. If one compares the present position of the Carpathian-Lesser Caucasus and Afghan-Tibet Meso-Tethyan sutures with the Late Cretaceous-early Cenozoic reconstructions of these sutures it is possible to trace the inner deformation of the Alpine belt. According to these data, the Carpathian-Lesser Caucasus suture moved northwards over 1200 km ahead of the Arabian-Turkish syntaxis with the displacement direction across the fold belt. At the border of the Dinarides and Hellenides, the displacement decreases to 400-500 km, and its direction is along the fold belt. The amplitude of the suture displacement increases in the Pannonian region and again decreases towards the Eastern Alps. The displacement of the Afghan-Tibet suture was > 2000 km during the Alpine deformation. A great ensemble of Cenozoic nappes, folds and structural arcs of the Pamir-Punjab and Arabian-Turkish syntaxes and Carpathian loop is the result of lateral shortening of the Alpine belt through the collision.

Burtman, V. S.

1994-07-01

152

Immunohistochemical assessment of cranial suture development in rats.  

Science.gov (United States)

The present study investigated, by immunohistochemistry, the postnatal occurrence and anatomical localisation of some bone and cartilage proteins and proteoglycans in the rat coronal sutural region. Thirty two Sprague-Dawley rats, four in each group, were killed at ages 3, 5, 8, 10, 15, 30, 50 and 100 days and the sutural region subsequently subjected to histological examination. The biochemical constituents investigated were: 36 kDa, 58 kDa, 59 kDa, 62 kDa, 148 kDa, 400 kDa proteins, chondrocalcin, bone sialoproteins I and II (BSP I and II), osteopontin (ost I), small cartilage 1 and 2 as well as large cartilage proteoglycans (PG-S1, PG-S2, PG-LA). Standard haematoxylin-eosin and laminin staining was also carried out. In general, detectable constituents were visualized until Day 50. Labelling of the proteins 59 kDa protein, BSP I and II, and ost I was distinct along the sutural bone margins and, initially, cells and fibrillar structures within the sutural ligament were also labelled. The 58 kDa protein was localised unspecifically to the suture tissue proper at Days 50 and 100. PG-S1 labelling was concentrated primarily at the sutural edge. Remaining substances were indistinguishable throughout the entire observation period. The dual response of proteoglycans in bone mineralisation and the potential importance of cartilaginous tissue in sutural closure is discussed. Images Fig. 1 Fig. 2 Fig. 3

Alberius, P; Johnell, O

1990-01-01

153

Interlocking circumareolar suture with undyed polyamide thread: a personal experience.  

Science.gov (United States)

In plastic breast surgery, the interlocking areolar suture has gained wide popularity since its introduction in 2007 by Hammond and colleagues. The interlocking circumareolar suture plays its role in the setting of circumareolar excisions to achieve a durable areola shaping and to prevent scar widening/hypertrophy and areola spreading/distortion. This study retrospectively reviewed 49 breasts that underwent interlocking suture after July 2011 for both aesthetic and reconstructive indications. For the suturing, 3-0 undyed polyamide thread with a straight cutting needle (Dafilon; B. Braun Melsungen AG, Melsungen, Germany) was used. This suture material was preferred to Gore-Tex reported by Hammond and colleagues because it is undyed without any microporous configuration, more wieldy, and less expensive. All 49 breasts showed good results in terms of areola shaping and diameter control as well as good scar quality during a mean follow-up period of 12 months (range 2-18 months) (Fig. 2). No infection, suture extrusion, skin fistula, or granuloma were experienced. The suture was not visible at all, and the patients did not report its palpability. However, at careful examination, the thread resulted slightly palpable. PMID:23860820

Salgarello, Marzia; Visconti, Giuseppe; Barone-Adesi, Liliana

2013-10-01

154

Crystallization and mechanical properties of the ultrafine ferric oxide-filled polypropylene and rheology of the filled polypropylene melt  

International Nuclear Information System (INIS)

Full text: Polypropylene was first blended with a series of ultrafine powder of ferric oxide with average diameters 16.1 nm, 41.3 nm, 73.0 nm, 184.0 nm, and 660.6 nm. The rheological property of the filled polypropylene melt was accessed in terms of equilibrium torques by using a Brabender plasticoder. The stress-strain behaviour was examined by using an Instron tensile tester. The crystallizing and melting processes of the filled polypropylene were followed by a Perkin-Elmer differential scanning calorimeter. And the degree of crystallinity was determined by the WAXD analysis. The data showed that the filled polypropylene had crystallized at higher temperature than the unfilled polypropylene. Whereas the ? form crystallinity of the polypropylene remained unchanged after it had been filled with ultrafine ferric oxide. Young's modulus of the filled polypropylene at room temperature decreased with decreasing of the filler's average diameter. But tensile strength of the filled polypropylene increased, approaching to that of unfilled polypropylene as the filler's average diameter getting smaller. Elongation at break remained constant during changing of the filler size. Better fluidity was found for smaller filler filled polypropylene melt. All the results manifest more researches to be done into the promising ultrafine filler

1996-02-02

155

Crystallization and mechanical properties of the ultrafine ferric oxide-filled polypropylene and rheology of the filled polypropylene melt  

Energy Technology Data Exchange (ETDEWEB)

Full text: Polypropylene was first blended with a series of ultrafine powder of ferric oxide with average diameters 16.1 nm, 41.3 nm, 73.0 nm, 184.0 nm, and 660.6 nm. The rheological property of the filled polypropylene melt was accessed in terms of equilibrium torques by using a Brabender plasticoder. The stress-strain behaviour was examined by using an Instron tensile tester. The crystallizing and melting processes of the filled polypropylene were followed by a Perkin-Elmer differential scanning calorimeter. And the degree of crystallinity was determined by the WAXD analysis. The data showed that the filled polypropylene had crystallized at higher temperature than the unfilled polypropylene. Whereas the {alpha} form crystallinity of the polypropylene remained unchanged after it had been filled with ultrafine ferric oxide. Young`s modulus of the filled polypropylene at room temperature decreased with decreasing of the filler`s average diameter. But tensile strength of the filled polypropylene increased, approaching to that of unfilled polypropylene as the filler`s average diameter getting smaller. Elongation at break remained constant during changing of the filler size. Better fluidity was found for smaller filler filled polypropylene melt. All the results manifest more researches to be done into the promising ultrafine filler

Gong Xiaoyi; Zeng Meizhen; Song Rongzhao [Chinese Academy of Sciences, Guangzhou (China). Guangzhou Institute of Chemistry]|[Chengdu Univ. of Science and Technology, SC (China). State Key Laboratory of Polymeric Materials Engineering

1996-12-31

156

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

157

Development and characterisation of injection moulded, all-polypropylene composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 f...

Kmetty, A.; Tabi, T.; Kovacs, J. G.; Barany, T.

2013-01-01

158

Possible superconductivity of oxidized polypropylene around 300 K  

Energy Technology Data Exchange (ETDEWEB)

The conductivity characteristics of oxidized polypropylene films 0.3-100 microns thick on copper or indium substrates was investigated experimentally at 293 K. In this temperature range, the oxidized polypropylene films exhibited a drop in resistance by 9 orders of magnitude down to zero as well as strong diamagnetism that was lost with the application of a magnetic field. It is shown that the conductivity of oxidized polypropylene is of the electron rather than ion nature. 5 refs.

Enikolopian, N.S.; Grogorov, L.N.; Smirnova, S.G. (Institut Sinteticheskikh Polimernykh Materialov, Moscow (USSR))

1989-03-01

159

Polypropylene : Morphology, defects and electrical breakdown  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2005-01-01

160

Creep rupture and viscoelastoplasticity of polypropylene  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Observations are reported on isotactic polypropylene in tensile tests with various strain rates, relaxation tests at various strains, and creep tests with various stresses at room temperature. Constitutive equations are derived for the viscoelastic and viscoplastic responses of semicrystalline polymers at three-dimensional deformations with small strains. The stress-strain relations involve eight material constants that are found by fitting the experimental data. The model is applied to the n...

2010-01-01

 
 
 
 
161

The nonlinear viscoelastic behavior of polypropylene  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Drozdov, A. D.; Christiansen, J. Dec

2002-01-01

162

EVALUATION OF COMPOSITE POLYPROPYLENE FIBRE REINFORCED CONCRETE  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Improvements in fly ash based concrete strength in compression and flexural direction are the main objectives of this study. The compressive and flexure strength of concrete for various mixtureproportions of concrete containing the inclusions of different percentage of polypropylene fibers from 0% to 0.3% and fly ash replacement levels at 25% , 50% of fly ash were investigated. The experimental test results showed that PP fibers possess increased extensibility and tensile strength, both at fi...

2013-01-01

163

Polypropylene and silica short fibers composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 v...

2012-01-01

164

Polypropylene matrix composites reinforced with coconut fibers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2011-01-01

165

Validation of material model for polypropylene (PP)  

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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

166

High strain rate behaviour of polypropylene microfoams  

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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 satu...

Go?mez-del, Ri?o T.; Garrido M.A.; Rodríguez J.; Arencón D.; Martínez A.B.

2012-01-01

167

Highly Filled Polypropylene Rubber Wood Flour Composites  

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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

168

EVALUATION OF COMPOSITE POLYPROPYLENE FIBRE REINFORCED CONCRETE  

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Full Text Available Improvements in fly ash based concrete strength in compression and flexural direction are the main objectives of this study. The compressive and flexure strength of concrete for various mixtureproportions of concrete containing the inclusions of different percentage of polypropylene fibers from 0% to 0.3% and fly ash replacement levels at 25% , 50% of fly ash were investigated. The experimental test results showed that PP fibers possess increased extensibility and tensile strength, both at first crack and at ultimate, particular under flexural loading; and the fibers were able to hold the matrix together even after extensive cracking. The net result of all these is to impart to the fiber composite pronounced post – cracking ductility which is absence of ordinary concrete. To provide a basis for comparison, reference concrete specimens were cast without polypropylene fiber. The experimental test result showed that the addition of polypropylene fibers at 0.1% volume fraction (Vf showed a consistent improvement in the concrete strength of 44.50 MPa and 55.50 MPa at 7 and 28 days respectively.

V.M. Sounthararajan

2013-04-01

169

High strain rate behaviour of polypropylene microfoams  

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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

170

Study on the Dynamic Performance of Polypropylene Fiber Reinforced Concrete  

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Full Text Available 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. The crack distributions of plain concrete and polypropylene concrete are investigated. The crack resistance effects of polypropylene fiber are analyzed from the degree of closeness and uniformity.

Zhang Ying

2013-12-01

171

Polypropylene surface modification by entrapment of polypropylene-graft-poly(butyl methacrylate)  

International Nuclear Information System (INIS)

Surface modification of polypropylene was carried out by entraping a copolymer of polypropylene grafted poly(butyl methacrylate) into polypropylene. The effects of structure of copolymers, contact die and content of modifiers on their surface enrichment were studied by attenuated total reflection infrared spectroscopy (ATR-FTIR), contact angle measurements and scanning electron microscopy (SEM). The results indicated that PPw-g-PBMA could diffuse preferably onto the surface and effectively increase the hydrophilicity of PP. Lower content and higher surface energy die were in favor of the copolymer to enrich on the PP surface. PPw-g-PBMA with low PBMA contents, short length of PBMA distributed in PP with smaller phase domains and favored its selective enrichment on the surface of PP, especially at lower loadings in blends. The modified material exhibited excellent solvent-resistance

2008-02-15

172

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

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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.

Maria de Fátima V. Marques

2001-10-01

173

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

Maria de Fátima V., Marques; Mariana, Poloponsky; Érica Gervasoni, Chaves.

174

Novel use of Prolene suture for duct delineation during microductectomy  

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Classically, microductectomy is performed using a probe inserted via the offending duct to delineate and identify the responsible duct. We propose the use of a 1-0 Prolene (Polypropene blue monofilament nonabsorbable) suture to cannulate the relevant duct.

Shiva Dindyal; Jayant Sharad Vaidya

2011-01-01

175

Obliteration of serrated sutures of a human skull (review)  

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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.; Kochenkova ?.V.; Anisimova ?.?.; Anisimov D.I.; Yu, Lukin ?.

2011-01-01

176

SUTURE NON-SUTSRE CIRCUMFERENTIAL REPAIR OF CAROTID ARTERY  

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Full Text Available plastic adhesives, normal butyl cyanoacrylate monomer, isobutyl cyanoacrylate monomer and methyl 2 _ cyaooacrylate monomer, have been utilized in a comparative study with 5-{ silk suture in the repair of transected carotid arteries. Follow _ up arteriog ramS indicate isobutyl cyanoacrylate monomer and normal butyl cyanoacrylate monomer as having the most impressive rerults with only tWO thrombosis each. The silk suture had three thromboses and the adhesive methyl 2 _ cyanoacrylate monomer had nine, one of which a delayed

Jafar Nader

1969-01-01

177

A transducer for measuring force on surgical sutures  

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The objective of this study was to validate, both in vitro and in an ex vivo model, a technique for the measurement of forces exerted on surgical sutures. For this purpose, a stainless steel E-type buckle force transducer was designed and constructed. A strain gauge was mounted on the central beam of the transducer to measure transducer deformation. The transducer was tested and calibrated on a single strand of surgical suture during cyclic loading. Further validation was performed using a pr...

Witte, Thomas H.; Cheetham, Jonathan; Rawlinson, Jeremy J.; Soderholm, L. Vince; Ducharme, Norm G.

2010-01-01

178

Strength of sliding knots in multifilament resorbable suture materials.  

Science.gov (United States)

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 tests. Sliding knots with three throws were compared with the five throw sliding knots, and a comparison of the loop-holding capacities (LHC) of the different suture materials was made. Differences in suture material, knot type, and number of throws in the knot had a remarkable effect on knot performance. Adding two extra throws to a three throw non-identical or parallel sliding knot resulted in significantly more reliable knots (P?suture materials, Safil showed significantly lower LHCs. Most of the mean LHCs of the various knots with Vicryl, Vicryl Plus or Novosyn were not statistically different from each other. Identical sliding knots appeared to be very unreliable, especially when made with three throws. Non-identical and parallel slipknots with five throws demonstrated superior knot integrity compared with the same knot types with three throws. Safil had inferior knot properties as compared to the other materials, but Vicryl, Vicryl Plus and Novosyn behaved virtually the same. The type of knot and the use of different suture materials have important influence on the integrity of the knot. A high knot reliability is nowadays all the more important because of the frequent use of resorbable suture materials. The suture gradually loses strength during the resorption process, so that an extra margin of safety neutralizes the effect of this process. PMID:23144642

van Leeuwen, Nourah; Trimbos, J Baptist

2012-11-01

179

Scar tissue orientation in unsutured and sutured corneal wound healing.  

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AIMS--This study aimed to evaluate stromal wound healing morphology in short term unsutured compared with sutured corneal wounds, to define regional variation in healing within radial keratotomy wounds. METHODS--Stromal scar tissue orientation (fibroblast and collagen fibre orientation) was analysed in unsutured and adjacent sutured keratotomy wounds in monkeys, 2 to 9 weeks after surgery, using light and transmission electron microscopy. RESULTS--At 2 to 4 weeks, scar tissue orientation was ...

Melles, G. R.; Binder, P. S.; Beekhuis, W. H.; Wijdh, R. H.; Moore, M. N.; Anderson, J. A.; Sundarraj, N.

1995-01-01

180

Single suture laparoscopic tubal re-anastomosis.  

Science.gov (United States)

The goal of this article is to report our experience and review recent articles obtained for laparoscopic tubal sterilization reversal. The technique we describe is 'single suture laparoscopic tubal re-anastomosis'. This technique is simple and atraumatic and requires only one stitch in the tube. After preparing the tube stumps and bringing the edges of the mesosalpinx together, laparoscopic anastomosis is achieved by one stitch placed at '12 o'clock' on the antimesial edge of the tube. Between May 1994 and June 1997 we operated on 32 patients using this technique and carried out 48 tubal sterilization reversals. For the patients who underwent postoperative hysterosalpingography during the first or second month after the operation, the rate of patency was 87.5% (42/48). The overall intrauterine pregnancy rate was 53.1% (17 out of 32 patients). The overall delivery rate was 40.6% (13 out of 32 patients). The intrauterine pregnancy rate for the 17 patients who were aged 38 years or under was 58.8% (10 out of 17 patients). Laparoscopic tubal sterilization reversal is feasible with a simplified technique. Review of the publications concerning laparoscopic microsurgical tubal anastomosis confirms satisfactory fertility results. The surgeon should be experienced in microsurgical tubal anastomosis by laparotomy as well as operative laparoscopic procedures. PMID:9719882

Dubuisson, J B; Chapron, C

1998-08-01

 
 
 
 
181

Development of braided drug-loaded nanofiber sutures  

Energy Technology Data Exchange (ETDEWEB)

The objectives of this work are twofold. Firstly, while most work on electrospinning is limited to the development of only functional materials, a structural application of electrospun nanofibers is explored. Secondly, a drug-loaded tissue suture is fabricated and its various properties are characterized. Braided drug-loaded nanofiber sutures are obtained by combining an electrospinning process with a braiding technique followed by a coating procedure. Two different electrospinning techniques, i.e. blend and coaxial electrospinning, to incorporate a model drug cefotaxime sodium (CFX-Na) into poly(L-lactic acid) (PLLA) nanofibers have been applied and compared with each other. Properties of the braided drug-loaded sutures are characterized through a variety of methods including SEM, TEM and tensile testing. The results show that the nanofibers had a preferable micromorphology. The drug was incorporated into the polymer nanofibers homogeneously, with no cross-linking. The nanofibers maintained their fibrous structures. An in vitro release study indicates that the drug-loaded nanofibers fabricated by blend electrospinning and coaxial electrospinning had a different drug release behavior. An inhibition zone experiment shows that both sutures obtained from the nanofibers of the different electrospinning techniques had favorable antibacterial properties. The drug-loaded sutures had preferable histological compatibility performance compared with commercial silk sutures in an in vivo comparative study.

Hu Wen [School of Materials Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Huang Zhengming [School of Aerospace Engineering and Applied Mechanics, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Liu Xiangyang, E-mail: huangzm@tongji.edu.cn [Department of Physics, National University of Singapore, 2 Science Drive 3, 117542 (Singapore)

2010-08-06

182

Age estimation by multidetector CT images of the sagittal suture.  

Science.gov (United States)

Closure of cranial sutures progresses with age; therefore, macroscopic assessment of cranial sutures has been used as one method of age estimation. Postmortem computed tomography (PMCT), which many forensic medical departments and institutes have begun to adopt, has the potential to simplify the gathering of information from cranial sutures for both surface and cross-sectional evaluation. To examine the feasibility of age estimation by cross-sectional multidetector computed tomography images of the sagittal suture, PMCT findings of 125 subjects of known age and sex were retrospectively reviewed. The sagittal suture was divided into four segments, and 20 cross-sectional slices from each segment were analyzed. These slices were each categorized by visual evaluation into one of the seven stages defined by Harth et al. according to the degree of closure. The mean stage value of 20 slices was calculated for each segment. We were able to evaluate cross-sectional images of the sagittal suture by PMCT, and a positive correlation between age and closure degree was observed. Despite the prediction interval achieved with this method not being superior to traditional macroscopic or flat-panel CT assessment, multidetector CT is a potentially useful tool, in conjunction with other methods, for age estimation, particularly in adult females and in cases where only a skull is the sole remain. PMID:23760604

Chiba, Fumiko; Makino, Yohsuke; Motomura, Ayumi; Inokuchi, Go; Torimitsu, Suguru; Ishii, Namiko; Sakuma, Ayaka; Nagasawa, Sayaka; Saitoh, Hisako; Yajima, Daisuke; Hayakawa, Mutsumi; Odo, Yuriko; Suzuki, Yoichi; Iwase, Hirotaro

2013-09-01

183

Iatrogenic Ulnar Nerve Injury post Laceration Suturing – An Unusual Presentation  

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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

184

The sutured Floer polytope and taut depth one foliations  

CERN Document Server

For closed 3-manifolds Ozsv\\'ath and Szab\\'o, Ni, and Hedden show that there exists a certain duality between an appropriate flavour of the Heegaard Floer polytope and the Thurston norm unit ball. For instance, extremal vertices of the HF^+ polytope carrying the group Z correspond bijectively to the fibred faces of the Thurston norm unit ball. We prove a similar result for sutured manifolds and taut depth one foliations. Equivalence classes of taut depth one foliations of a sutured manifold form foliation cones, defined by Cantwell and Conlon. We show that the extremal vertices of the sutured Floer polytope carrying the group Z correspond bijectively to these foliation cones. Moreover, the foliation cones are subtended by the foliated faces of an asymmetric seminorm arising from the dual sutured Floer polytope. In some cases this seminorm has a purely geometric definition akin to that of the sutured Thurston norm. An important step in our work is the following fact: a sutured manifold admits a fibration or a ...

Altman, Irida

2012-01-01

185

Effects of two suture techniques in conjunctival autograft surgery  

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Full Text Available AIM: To compare the effects of continuous side whipstitch suture and interrupted suture in conjunctival autograft surgery after resection of primary pterygium.METHODS: A comparative, prospective and randomized clinical trial was performed in 48 eyes of 48 patients with primary pterygium. All patients were randomly divided into two groups with 24 eyes of 24 patients in each group. In group A and B, continuous side whipstitch suture and interrupted suture were respectively adopted. The time spent in suture was recorded during surgery. The postoperative ocular discomfort and the time spent in taking out stitches were recorded during the 6-month follow-up. RESULTS: The average surgical time was 14.05±2.30 minutes for group A and 19.34±2.12 minutes for group B(Prd (1.32±0.60 vs 1.68±0.35, Pth(0.87±0.24 vs 1.26±0.68, PPCONCLUSION: In the surgical management of primary pterygium, continuous side whipstitch suture can improve the surgical efficiency and decrease the ocular discomfort in the postoperative period. It proves to be an excellent option for conjunctival autograft attachment in primary pterygium surgery.

Chao-Peng Li

2013-09-01

186

Effect of Suture Lines on Lung Adenocarcinoma Cell in vitro  

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Full Text Available Background and objective The interaction of cell and medical biomaterial is one of the significant factors to affect clinical application of medical biomaterial. This research is to investigate three of suture lines how to affect the proliferation and cell cycle of Lung Adenocarcinoma cell A549. Methods Three of suture lines are respectively cultivated with Lung Adenocarcinoma cell A549, after of 72 hours, to detect absorptance of each groups by MTT method in order to reflect the proliferation of Lung Adenocarcinoma cell A549 and to detect percentage of G1 period cell and S period cell of each of groups by flow cytometry. Results Different of suture lines have effect differently on the proliferation and cell cycle of Lung Adenocarcinoma cell A549 (P < 0.05. The effect of absorbent suture line on the proliferation and cell cycle of Lung Adenocarcinoma cell A549 is strong, the effect of chorda serica chirurgicalis is medium, the effect of slide wire is poor. Different length of each suture line have effect differently on the proliferation and cell cycle of Lung Adenocarcinoma cell A549 (P < 0.05. Conclusion Three of suture line materials have different effect on the proliferation and cell cycle of Lung Adenocarcinoma cell A549, to reflect dose-effect relation.

Lianhua YE

2009-09-01

187

Load transmission in the nasofrontal suture of the pig, Sus scrofa  

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The nasofrontal suture links the nasal complex with the braincase and is subject to compressive strain during mastication and (theoretically) tensile strain during growth of nasal soft tissues. The suture’s ability to transmit compressive and tensile loads therefore affects both cranioskeletal stress distribution and growth. This study investigated the in vitro viscoelastic and failure properties of the nasofrontal suture in the pig, Sus scrofa. Suture specimens from two ages were tested in...

Popowics, Tracy E.; Herring, Susan W.

2007-01-01

188

Early Experience With Barbed Sutures for Abdominal Closure in Deep Inferior Epigastric Perforator Flap Breast Reconstruction  

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Objective: Barbed sutures have recently been introduced for closure of surgical incisions. These self-anchoring sutures incorporate evenly spaced barbs in a circumferential distribution along their length, facilitating knotless wound closure and even distribution of tension along the suture line. In this study, we evaluated postoperative complications associated with the use of unidirectional barbed sutures compared with standard sutures for closure of the abdominal incision in deep inferior ...

Blacam, Catherine; Colakoglu, Salih; Momoh, Adeyiza O.; Lin, Samuel J.; Tobias, Adam M.; Lee, Bernard T.

2012-01-01

189

Efeitos cardiovasculares e midriáticos da fenilefrina tópica a 2,5 e a 10,0% em voluntários sadios Cardiovascular and pupillary effects of topical ophthalmic 2.5 and 10.0% phenylephrine in healthy volunteers  

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Full Text Available OBJETIVO: Comparar os efeitos cardiovasculares e midriáticos da fenilefrina tópica nas concentrações de 2,5 e 10,0%. MÉTODOS: Ensaio clínico do tipo caso controle, randomizado, com auto-emparelhamento. Foram monitoradas a freqüência cardíaca (FC, a pressão arterial (PA e a midríase em voluntários sadios, com idade entre 18 e 45 anos, após a instilação da fenilefrina a 2,5 e a 10,0% em duas ocasiões diferentes. RESULTADOS: A amostra foi constituída de 28 voluntários, sendo 17 do sexo masculino e 11 do sexo feminino, com a idade média de 26,5 anos. Não foi verificado nenhum padrão de mudanças com relação à freqüência cardíaca e à pressão arterial sistólica. Com relação à pressão arterial diastólica média dos indivíduos, não foi encontrada variação significativa após a instilação da fenilefrina a 2,5% nos tempos de um, cinco, dez e 30 minutos, o que se revelou bem diferente quando do uso da fenilefrina a 10,0%, com a qual houve aumento da pressão arterial diastólica média após cinco e dez minutos, e subseqüente queda após 30 minutos, porém sem significância estatística. A midríase foi maior com a fenilefrina a 10,0% nos dois olhos, sendo a diferença estatisticamente significativa. CONCLUSÕES: Observou-se maior efeito midriático da fenilefrina a 10,0%, quando comparada a 2,5%, com significância estatística. Já com relação aos efeitos cardiovasculares não houve diferença estatística entre as duas concentrações.PURPOSE: To compare the cardiovascular and mydriatic effects of 2.5% and 10.0% phenylephrine. METHODS: A case-control, randomized, crossover clinical trial study. We monitored heart rate (HR, blood pressure (BP and mydriasis in healthy volunteers aged 18-45 years after the instillation of 2.5% and 10.0% phenylephrine in two different occasions. RESULTS: The sample comprised 28 healthy volunteers, 17 male and 11 female, with a mean age of 26.5 years. No changes in heart rate and systolic blood pressure were observed. No significant variation of the mean diastolic blood pressure was found after 1, 5, 10 and 30- minute instillation of 2.5% phenylephrine. However, with 10.0% phenylephrine, there was an increase in mean diastolic blood pressure after five and ten minutes, followed by a drop after 30 minutes, which was not statistically significant. Mydriasis was more marked in both eyes with a statistically significant difference after instillation of 10.0% phenylephrine. CONCLUSIONS: The mydriatic effect was greater with 10.0% phenylephrine than with 2.5% phenylephrine and the difference was statistically significant. No statistically significant difference was found in relation to cardiovascular effects in both phenylephrine concentrations.

Alberto Diniz Filho

2007-12-01

190

Cierre de la pared abdominal: qué técnica y qué sutura se deben usar Closing the abdominal wall: what technique and type of suture to use  

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Full Text Available Introducción: El cierre de la pared abdominal es un procedimiento frecuente en la práctica de los cirujanos generales. El tipo de cierre y el material de sutura en la mayoría de los casos se realizan y escogen en forma empírica. El presente estudio valora la mejor evidencia disponible sobre la técnica para el cierre de la fascia abdominal y el tipo de sutura. Métodos: Se realizó una búsqueda sistemática de la literatura y se evaluaron los artículos de más alta calidad (revisiones sistemáticas. Los resultados se analizaron particularmente. Resultados: La mejor técnica de sutura de la fascia abdominal es aquella con puntos continuos con material de absorción lenta (polidioxanona o no absorbible (polipropileno, los cuales tienen índices de hernia incisional menores que las suturas de absorción rápida. Conclusiones: Es recomendable utilizar sutura de material de absorción lenta o no absorbible para el cierre de la pared abdominal.Introduction: Closure of the abdominal wall is a frequently performed procedure in general surgical practice. The type of closure and the suture material are often chosen on empirical bases. The present study evaluates the best evidence available regarding the technique of closure of the abdominal wall and the best suture material to be used. Methods: A systematic literature search was undertaken and the best quality articles (systematic reviews were analyzed. Results: The best technique appears to be the closure with interrupted sutures of slow absorption (polydioxanone or non absorbable (polypropylene material, which exhibit lower recurrence rates that those observed with materials of rapid absorption. Conclusions: It is recommended to utilize interrupted sutures of slow absorption or non absorbable material for closing the abdominal wall.

Carlos Lehmann

2007-06-01

191

Fracture Toughness Studies of Polypropylene- Clay Nanocomposites and Glass Fibre Reinfoerced Polypropylene Composites  

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Full Text Available In this paper, a comparative study on the fracture toughness of woven glass fibre reinforced polypropylene, chopped glass fibre reinforced polypropylene and nanoclay filled polypropylene composites is presented. Nanoclays (Cloisite 15A of 1 wt. % to 5 wt. % were filled in polypropylene (PP matrix and they were subjected to fracture toughness stu-dies. The specimen with 5 wt. % nanoclay showed 1.75 times and 3 times improvement in critical stress intensity factor (KIC and strain energy release rate (GIC, respectively, over virgin PP. On the other hand, 3 wt. % nanoclay PP composites showed superior crack containment properties. These structural changes of composite specimens were examined using Transmission Electron Microscopy (TEM and X-ray diffraction (XRD methods. It showed that exfoli-ated nanocomposite structures were formed up to 3 wt. % nanoclay, whereas, intercalated nanocomposite structures formed above 3 wt. % nanoclay in the PP matrix. Furthermore, the woven fibre reinforced PP composites demonstrated superior crack resistant properties than that of clay filled nanocomposites and chopped fibre PP composites. However, KIC and GIC values for woven fibre composites were lesser than that of chopped fibre composites. Moreover, KIC and GIC values for both nanoclay filled PP composites and woven fibre composites are comparable even though the clay filled PP demonstrated catastrophic failure. Also, the crack propagation rate of PP-nanoclay composites is comparable to that of chopped fibre composites.

A. Ramsaroop

2010-12-01

192

The fire resistance of concrete with polypropylene fibers  

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This paper presents the results and conclusions of an experimental study characterization performed on the polypropylene fibers for use in concretes (NPC, Normal Performance Concrete) to produce an improvement in the durability against exposure to high temperatures. It was used only one type of polypropylene fiber with two different lengths, 6?mm and 12?mm, to evaluate the effect of the length.

2013-01-01

193

Midwives conducting perineal repair: The Danish Suture Trial  

DEFF Research Database (Denmark)

Midwives conducting perineal repair: The Danish Suture Trial.     Background Suture techniques and materials for repair of 2nd degree perineal lacerations and episiotomies have been tested in several clinical trials. Danish midwives and obstetricians have developed a new, simple and time-efficient suture technique which needed systematic evaluation. Objective To compare two standardized suture techniques for perineal repair of 2nd degree perineal lacerations or episiotomies. Design and setting A double-blind randomised clinical trial conducted in Aarhus University Hospital, Denmark. Initiated August 2004, enrolment of patients finished October 2005. Sample size: 400. Inclusion: Healthy primipara sustaining a 2nd degree perineal laceration or an episiotomy following vaginal birth. Perineal repair was carried out by a midwife. Exclusion: Lacerations involving the sphincter ani, post partum haemorrhage >1000 ml, Diabetes, mental disorders. Both suture techniques were 2-layered using a polyglactin910 multifilament suture (Vicryl Rapid or Vicryl). Treatment A was a continuous suture technique and treatment B was interrupted, inverted stitches. Primary outcomes: Perineal pain and wound healing assessed day 1-2 and 10 post partum. Secondary outcomes: patient satisfaction with wound healing, need for secondary repair, superficial pain during intercourse.   Data management: Double entry of all data and intention-to-treat analysis.   Results The follow up rate was 97%. Baseline data were evenly distributed between the two treatment groups. Major difference in pain and healing was observed between spontaneous lacerations and episiotomies. Follow up 6 months post partum will be finished by April 2006.   Conclusion Primary results will be presented on the NFOG Congress in Göteborg, May 2006.

Kindberg, Sara

2007-01-01

194

Effect of recombinant human platelet-derived growth factor-BB-coated sutures on Achilles tendon healing in a rat model: A histological and biomechanical study  

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Full Text Available Purpose: Repairing tendon injuries with recombinant human platelet-derived growth factor-BB has potential for improving surgical outcomes. Augmentation of sutures, a critical component of surgical tendon repair, by coating with growth factors may provide a clinically useful therapeutic device for improving tendon repair. Therefore, the purpose of this study was to (a coat Vicryl sutures with a defined dose of recombinant human platelet-derived growth factor-BB without additional coating excipients (e.g. gelatin, (b quantify the recombinant human platelet-derived growth factor-BB released from the suture, and (c use the recombinant human platelet-derived growth factor-BB-coated sutures to enhance tendon repair in a rat Achilles tendon transection model. Methods: Vicryl sutures were coated with 0, 0.3, 1.0, and 10.0 mg/mL concentrations of recombinant human platelet-derived growth factor-BB using a dip-coating process. In vitro release was quantified by an enzyme-linked immunosorbent assay. Acutely transected rat Achilles tendons were repaired using one of the four suture groups (n = 12 per group. Four weeks following repair, the tensile biomechanical and histological (i.e. collagen organization and angiogenesis properties were determined. Results: A dose-dependent bolus release of recombinant human platelet-derived growth factor-BB occurred within the first hour in vitro, followed by a gradual release over 48 h. There was a significant increase in ultimate tensile strength (p < 0.01 in the two highest recombinant human platelet-derived growth factor-BB dose groups (1.9 ± 0.5 and 2.1 ± 0.5 MPa relative to controls (1.0 ± 0.2 MPa. The modulus significantly increased (p = 0.031 with the highest recombinant human platelet-derived growth factor-BB dose group (7.2 ± 3.8 MPa relative to all other groups (control: 3.5 ± 0.9 MPa. No significant differences were identified for the maximum load or stiffness. The histological collagen and angiogenesis scores were comparable in all groups, although there was a trend for improved collagen organization in the recombinant human platelet-derived growth factor-BB-treated groups (p = 0.054. Conclusions: The results of this study suggest that recombinant human platelet-derived growth factor-BB can be used to reproducibly coat Vicryl sutures and improve remodeling in a rat Achilles tendon transection model by significantly decreasing the resulting cross-sectional area, thus improving the material properties of the repaired tendon.

Stephen H Cummings

2012-07-01

195

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 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)

2009-05-01

196

Disposable circumcision suture device: clinical effect and patient satisfaction.  

Science.gov (United States)

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 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. PMID:24759586

Lv, Bo-Dong; Zhang, Shi-Geng; Zhu, Xuan-Wen; Zhang, Jie; Chen, Gang; Chen, Min-Fu; Shen, Hong-Liang; Pei, Zai-Jun; Chen, Zhao-Dian

2014-01-01

197

Punto interdomal en técnica cerrada / Interdomal suture in closed approach  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish El manejo de la punta nasal es un elemento clave en toda rinoplastía. Las primeras técnicas empleadas sacrificaban la estructura del arco alar con resultados posoperatorios indeseables. En la era moderna de la rinoplastía, el manejo de la punta nasal se enfocó en remodelar, preservar y reposicionar [...] los cartílagos alares mediante el uso de suturas. El punto interdomal es una sutura en forma de ocho o loop simple desde la porción más anterior de un domo hacia el contralateral uniendo la región más alta de las cruras mediales. En el presente artículo se realiza una revisión del uso de puntos de suturas en el manejo de la punta nasal, se describen las características del punto interdomal en técnica cerrada y se muestran sus resultados en una serie de casos. Abstract in english The nasal tip surgery is a key element in rhinoplasty. The first techniques employed sacrificed the alar arch structure with undesirable postoperative results. In the modern era of rhinoplasty, nasal tip surgery focused on reshaping, preserving and repositioning the alar cartilages using reversible [...] sutures. The interdomal suture is a figure-eight or simple loop suture placed from the most anterior portion of one dome to the contralateral joining the highest region of the medial crura. This article reviews the use of suture techniques in nasal tip reshaping and describes the interdomal suture in closed approach and its results in a clinical series.

Arias A, Roberto; Rodríguez H, Leandro; Rojas O, Mónica; Bogado C, Mariana.

198

Mechanical Behavior of Bio-inspired Model Suture Joints  

Science.gov (United States)

Suture joints of varying degrees of geometric complexity are prevalent throughout nature as a means of joining structural elements while providing locally tailored mechanical performance. Here, micromechanical models of general trapezoidal waveforms of varying hierarchy are formulated to reveal the role of geometric complexity in governing stiffness, strength, toughness and corresponding deformation and failure mechanisms. Physical constructs of model composite suture systems are fabricated via multi-material 3D printing (Object Connex500). Tensile tests are conducted on samples covering a range in geometry, thus providing quantitative measures of stiffness, strength, and failure. The experiments include direct visualization of the deformation and failure mechanisms and their progression, as well as their dependence on suture geometry, showing the interplay between shear and tension/compression of the interfacial layers and tension of the skeletal teeth and the transition in failure modes with geometry. The results provide quantitative guidelines for the design and tailoring of suture geometry to achieve the desired mechanical properties and also facilitate understanding of suture growth and fusion, and evolutionary phenotype.

Li, Yaning; Lin, Erica; Ortiz, Christine; Boyce, Mary

2012-02-01

199

Material properties of common suture materials in orthopaedic surgery.  

Science.gov (United States)

Suture materials in orthopaedic surgery are used for closure of wounds, repair of fascia, muscles, tendons, ligaments, joint capsules, and cerclage or tension band of certain fractures. The purpose of this study was to compare the biomechanical properties of eleven commonly used sutures in orthopaedic surgery. Three types of braided non-absorbable and one type of braided absorbable suture material with different calibers (n=77) underwent biomechanical testing for maximum load to failure, strain, and stiffness. All samples were tied by one surgeon with a single SMC (Seoul Medical Center) knot and three square knots. The maximum load to failure and strain were highest for #5 FiberWire and lowest for #0 Ethibond Excel (pFiberWire and lowest for #2-0 Vicryl (p<0.001). In all samples, the failure of the suture material occurred at the knot There was no slippage of the knot in any of the samples tested. This data will assist the orthopaedic surgeon in selection and application of appropriate suture materials and calibers to specific tasks. PMID:21045977

Najibi, S; Banglmeier, R; Matta, Jm; Tannast, M

2010-01-01

200

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

 
 
 
 
201

Complexity of serrated sutures of a human skull  

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Full Text Available Objective: to reveal the variability mechanism of complexity of serrated sutures of a human skull in the correlation with cranial form. Materials and methods. Researches of 253 arches of male and female skulls of patients at the age of 1 day-105 years without signs of cranial trauma or skeletal systemic diseases with absence of morphological signs of increase of intracranial pressure. Minimal (Min and maximal (Max values, average arithmetic (M, a mistake of average arithmetic (m have been studied. For definition of reliability of average size difference parametrical and non-parametric statistical criteria were used: parametrical criterion (t-criterion of Student applied for parameters submitting to the law of normal distribution (Lakin G. R, 1990. Distinctions of average arithmetic size were considered statistically authentic from 95% (p<0,05 a level of correct judgement (Plokhinskiy N.A., 1970. Results. On the surface of the arch lambdoid and coronal sutures in male skulls and lambdoid and sagittal sutures in female were found out to be of the greatest degree of complexity. Conclusion. The increase of complexity of sutures has been observed in children and adolescents; the directed asymmetry of sutures form is absent

Kochenkova ?.V.

2011-09-01

202

Efeitos cardiovasculares e midriáticos da fenilefrina tópica a 2,5 e a 10,0% em voluntários sadios / Cardiovascular and pupillary effects of topical ophthalmic 2.5 and 10.0% phenylephrine in healthy volunteers  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese OBJETIVO: Comparar os efeitos cardiovasculares e midriáticos da fenilefrina tópica nas concentrações de 2,5 e 10,0%. MÉTODOS: Ensaio clínico do tipo caso controle, randomizado, com auto-emparelhamento. Foram monitoradas a freqüência cardíaca (FC), a pressão arterial (PA) e a midríase em voluntários [...] sadios, com idade entre 18 e 45 anos, após a instilação da fenilefrina a 2,5 e a 10,0% em duas ocasiões diferentes. RESULTADOS: A amostra foi constituída de 28 voluntários, sendo 17 do sexo masculino e 11 do sexo feminino, com a idade média de 26,5 anos. Não foi verificado nenhum padrão de mudanças com relação à freqüência cardíaca e à pressão arterial sistólica. Com relação à pressão arterial diastólica média dos indivíduos, não foi encontrada variação significativa após a instilação da fenilefrina a 2,5% nos tempos de um, cinco, dez e 30 minutos, o que se revelou bem diferente quando do uso da fenilefrina a 10,0%, com a qual houve aumento da pressão arterial diastólica média após cinco e dez minutos, e subseqüente queda após 30 minutos, porém sem significância estatística. A midríase foi maior com a fenilefrina a 10,0% nos dois olhos, sendo a diferença estatisticamente significativa. CONCLUSÕES: Observou-se maior efeito midriático da fenilefrina a 10,0%, quando comparada a 2,5%, com significância estatística. Já com relação aos efeitos cardiovasculares não houve diferença estatística entre as duas concentrações. Abstract in english PURPOSE: To compare the cardiovascular and mydriatic effects of 2.5% and 10.0% phenylephrine. METHODS: A case-control, randomized, crossover clinical trial study. We monitored heart rate (HR), blood pressure (BP) and mydriasis in healthy volunteers aged 18-45 years after the instillation of 2.5% and [...] 10.0% phenylephrine in two different occasions. RESULTS: The sample comprised 28 healthy volunteers, 17 male and 11 female, with a mean age of 26.5 years. No changes in heart rate and systolic blood pressure were observed. No significant variation of the mean diastolic blood pressure was found after 1, 5, 10 and 30- minute instillation of 2.5% phenylephrine. However, with 10.0% phenylephrine, there was an increase in mean diastolic blood pressure after five and ten minutes, followed by a drop after 30 minutes, which was not statistically significant. Mydriasis was more marked in both eyes with a statistically significant difference after instillation of 10.0% phenylephrine. CONCLUSIONS: The mydriatic effect was greater with 10.0% phenylephrine than with 2.5% phenylephrine and the difference was statistically significant. No statistically significant difference was found in relation to cardiovascular effects in both phenylephrine concentrations.

Alberto, Diniz Filho; Maria, Frasson; Rafael Vidal, Mérula; Patrick Reis, Morais; Sebastião, Cronemberger.

203

Single-helix crystal in atactic polypropylene  

Science.gov (United States)

The conformational arrangement of a locally stereoregular sequence of atactic polypropylene (aPP) was investigated via X-ray diffraction, thermal analysis, and infrared spectroscopy. Since the aPP used was an isotactic-rich sample, the X-ray diffraction pattern showed the typical profile of an ?-iPP (isotactic polypropylene) crystal, indicating that the crystal is constructed from locally stereoregular sequences. Even for a sample with low stereoregularity (meso pentad = 16%), small peaks due to ?-iPP crystals were observed. The melting temperature of aPP was reduced compared with an ?-iPP crystal. This corresponds to a shortening of the lamellar thickness. Helical units from chloroform insoluble and soluble fractions having meso pentads of 0.64 and 0.16, respectively, were composed of 3.5 and 1.2 repeating units, respectively. Such short conformational order was also confirmed by infrared spectroscopy. In general, a conformationally sensitive band is observed over a critical regular sequence (n). For the chloroform soluble fraction, a 977 cm-1 band for n = 5 was observed, but the typical 998 and 841 cm-1 bands for n = 11-12 and 13-15, respectively, were not observed. This signals that the regular conformation consists of 1-2 repeating units. It is concluded that a short conformational order (about 1-2 helical units) can construct the crystalline unit for aPP.

Nakaoki, Takahiko; Fukui, Daisuke

2013-11-01

204

Suture Retention Strength of Expanded Polytetrafluoroethylene (ePTFE Graft  

Directory of Open Access Journals (Sweden)

Full Text Available

Our meticulous investigation of ePTFE graft breakage when a wire placed at the edge of an ePTFE graft was pulled, revealed that, depending on the breakage pattern, a break starts much earlier than the peak suture retention strength, which is the current international indicator for anastomotic-site break strength. Furthermore, the breakage patterns differ based on the thickness of the wire and the fiber direction of the ePTFE graft. Based on these findings, we advocate measuring the peak suture retention strength using 0.10-mm sutures and a standardized wire thickness in order to assess the anastomotic retention strength of ePTFE grafts.

Mine,Yoshinari

2010-04-01

205

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

International Nuclear Information System (INIS)

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 (Ea), 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 13C NMR CP-MAS techniques were used to propose the decomposition mechanism of C4 in the presence of PP.

2011-03-10

206

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

207

Prosthetic abdominal wall hernia repair in emergency surgery: from polypropylene to biological meshes  

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Full Text Available Abstract The use of nonabsorbable prosthetic materials such as polypropylene, polyester, and ePTFE, have expanded and are now widely used in reparative surgery for abdominal wall hernias. There are still difficulties to find correct indication for prosthetic implant in emergency hernia surgery: as a matter of fact there is still a great debate if to use non-absorbable prostheses in potentially or truly infected operating fields [e.g. after intestinal resections]. All these problems can be avoided with the use of absorbable prosthetic materials such as those composed of lactic acid polymers or lactic and glycolic acid copolymers: however, the use of these absorbable prosthesis exposes the patient to a rapid and inevitable hernia recurrence. It is important to remember that prosthetic repair has been proven to have a significant less risk of recurrence than repair with direct sutures. Recently, new "biologic" prosthetic materials have been developed and proposed for the clinical use in infected fields. These materials can be called "remodeling" for the way by which they are replaced after their placement within the patient. The "remodeling" process is made possible through a process of incorporation, where a reproduction of a site-specific tissue similar to the original host tissue is created.

Campanelli G

2008-12-01

208

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

209

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 SciELO Brazil | Language: English Abstract in portuguese 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.

210

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

211

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

1994-09-02

212

Deformation characteristics of polypropylene melts in the supercooled state  

Energy Technology Data Exchange (ETDEWEB)

On a PIRP (cone-plate) rheogoniometer the viscous and viscoelastic properties of polypropylene were investigated in the temperature interval 140-230/sup 0/, (including the equilibrium melting point 180/sup 0/). It was found that a polypropylene melt behaves as a Newtonian liquid, but shows different properties in the temperature intervals above and below 190/sup 0/. The observable effect is connected with the transition of the system from the isotropic to the liquid-crystal state. With a constant deformation of the crystallizing polypropylene melt, samples are obtained for which the given effect is absent.

Baranov, V.G.; Beder, L.M.; Bolotnikova, L.S.; Frenkel, S.Ya.; Panov, Yu.N.

1982-01-01

213

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

214

Effects of gamma irradiation on polypropylene, polypropylene + high density polyethylene and polypropylene + high density polyethylene + wood flour  

International Nuclear Information System (INIS)

The effect of the gamma-irradiation on the mechanical properties of the composites, Polypropylene (PP), PP+high density Polyethylene (HDPE), PP+ HDPE+wood flour, where HDPE is virgin and recycled, was studied. This paper discusses the behavior of the composites after exposure to various doses of gamma irradiation (1-7 MRads) in the presence of oxygen. The dependence of mechanical properties on the integral dose for a constant dose rate of 0.48 MRads/h confirms the influence of the irradiation. Strong effects on the elongation at break and break strength is noticed. The mathematical analysis suggests for the PP+r-HDPE a bimolecular process of the elongation at break. On the order hand, for the PP+HDPE a complex process is represented for a three exponential equation. (orig.)

2001-04-01

215

Material properties of glass filled blends of polypropylene, polyamide, and maleated polypropylene  

Energy Technology Data Exchange (ETDEWEB)

The blending of polymers to achieve mixtures of intermediate properties has long been recognized as an efficient alternative to developing new polymers. This study was undertaken to explore the feasibility and efficiency of producing a blend comparable to commercial polyamides using less expensive polypropylene blended with polyamide and reinforced with glass fibers. The data taken on these blends indicate that several of the formulations would be materially comparable to, as well as cost competitive with, current polyamides.

Bigio, D.; Briber, R.; Marks, C. [Univ. of Maryland, College Park, MD (United States)

1996-12-31

216

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

217

Prospective randomized controlled trial investigating the type of sutures used during hepatectomy  

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AIM: To determine whether absorbable sutures or non-absorbable sutures are better in preventing surgical site infection (SSI), in this paper we discuss the results of a randomized clinical trial which examined the type of sutures used during hepatectomy. METHODS: All hepatic resections performed from January 2007 to November 2008 at the Department of Surgery at Iizuka Hospital in Japan were included in this study. There were 125 patients randomly assigned to an absorbable sutures (Vicryl) gro...

Norifumi Harimoto; Ken Shirabe; Tomoyuki Abe; Takafumi Yukaya; Eiji Tsujita; Tomonobu Gion; Kiyoshi Kajiyama; Takashi Nagaie

2011-01-01

218

Microbial adherence on various intraoral suture materials in patients undergoing dental surgery  

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PURPOSE: Sutures used in oral surgery should avoid or limit bacterial adhesion and proliferation to those parts exposed to oral fluids. Hence, microbial colonization on various intraoral suture materials from patients undergoing dental surgery was compared. PATIENTS AND METHODS: During dentoalveolar surgery, various suture materials were used in 60 patients, who were randomly divided into 5 groups of 12. In each group, silk was placed intraorally in association with a different type of suture...

Cuffini, Annamaria; Roana, Janira; Tullio, Viviana; Mandras, Narcisa; Banche, Giuliana; Gallesio, Cesare; Angeretti, Alessandra; Allizond, Valeria

2007-01-01

219

Electron beam modification of polypropylen fabrics  

International Nuclear Information System (INIS)

In this study, Electron bombardment with the energy of 10-40 Kev and different period of time has been carried out. Electron beam processing of polypropylene (PP) fabrics is found to promote significant changes in physical and chemical properties. The obtained data show that, electron beam processing of PP fabrics allows an adjustable modification of their surface properties. The functional groups on the surface of samples were examined using FTIR spectrometer. Moreover, dyeing properties for treated fabrics has been tested. Relative increase in color strength has been achieved. Morphology of samples was examined by Scanning Electron Microscopy (SEM). The absorption times and contact angle were utilized to analyze the result of the treated samples. This process is promising for the compatibilization of PP fiber and matrix with various compound in blends and production of multilayered composites for versatile applications such as laminates and supported compound. (author)

2008-10-01

220

Effect of Electron Irradiation on Polypropylene Films  

International Nuclear Information System (INIS)

Effects of both electron beam irradiation on the properties of polypropylene (PP) films and the irradiation on the different layers of a multilayer PP film are studied. A Fourier transform infrared spectroscope was used to investigate the chemical structure of the films. The results showed that the chemical properties of the first layer were improved, that is, more functional groups responsible for dye ability and hydrophilicity of the film were produced on its surface, while noticeable improvement was not detected on the surface of other layers. This was also confirmed by testing the dye ability of the layers. However, the results obtained by atomic force microscopy showed that the electron irradiation caused some topographical changes, not only on the surface of the first layer but also on the others. (low temperature plasma)

2011-04-01

 
 
 
 
221

Percutaneous Mesh Expansion and Fixation at the Retro-Rectus Plane without Stabs by Using Redirecting Suture Hook in Midline Hernias Repair  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Mesh expansion and fixation at retro-rectus plane through multiples stabs produces good results. But these stabs cause cosmetic disorders for the patients and doctors. So, we find some modification to do this procedure without these stabbing wounds in midline hernial repair. Patients and methods: This technique was used to fix the mesh at retro-rectus plane in 50 patients suffering from midline hernias, from January 2008 through January 2010 at Zagazig university Hospital, Egypt. Laparotomy incision was done over the hernial sac or at old incision; the contents were then released and reduced into peritoneal cavity without much subcutaneous dissection. The suitable sheet of polypropylene mesh to cover the hernial defect and any weak area was prepared and fixed at retro-rectus plane percutaneously without stabbing wounds by using redirecting suture hook. The mean period of follow up was 26 months. Results: There was no recurrence during the period of follow up. Five patients developed subcutaneous bluish discoloration at the site of some stitches, which disappear within two weeks with conservative treatment. Conclusion: Percutaneous mesh expansion and fixation at retro-rectus plane by using redirecting suture hook procedure has good results in recurrence rate and cosmetic appearance.

Ayman F Mehanna

2011-06-01

222

Barbed Suture for Vaginal Cuff Closure in Laparoscopic Hysterectomy  

Science.gov (United States)

Background and Objectives: Our aim was to evaluate whether the use of barbed suture for vaginal cuff closure is associated with a decrease in postoperative vaginal bleeding compared with cuff closure with polyglactin 910 in patients who have undergone laparoscopic hysterectomy. Methods: We performed a cohort study of patients who underwent laparoscopic hysterectomy between January 2008 and July 2012 by the minimally invasive gynecologic surgery division of the Gynecology, Obstetrics and Human Reproduction Department at Fundación Santa Fe de Bogotá University Hospital, Bogotá, Colombia. Results: A total of 232 women were studied: 163 were in the polyglactin 910 group, and 69 were in the barbed suture group. The main outcome, postoperative vaginal bleeding, was documented in 53 cases (32.5%) in the polyglactin 910 group and in 13 cases (18.8%) in the barbed suture group (relative risk, 0.57; 95% confidence interval, 0.34–0.9; P = .03). No statistically significant differences were found in other postoperative outcomes, such as emergency department admission, vaginal cuff dehiscence, infectious complications, and the presence of granulation tissue. Conclusion: In this study an inverse association was observed between the use of barbed suture for vaginal cuff closure during laparoscopic hysterectomy and the presence of postoperative vaginal bleeding.

Medina, Byron Cardoso; Riano, Giovanni; Hoyos, Luis R.; Otalora, Camila

2014-01-01

223

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

2014-02-01

224

Neonatal subperiosteal cephalohematoma crossing a synostosed sagittal suture  

Energy Technology Data Exchange (ETDEWEB)

A newborn boy, born at term by a spontaneous delivery, presented in the first day of life with a soft-tissue mass across a synostosed segment of the sagittal suture. In the following week the mass became better defined and showed peripheral calcifications consistent with a calcified subperiosteal hematoma. (orig.)

Currarino, Guido [Texas Scottish Rite Hospital, Department of Radiology, Dallas, TX (United States)

2007-12-15

225

Novel use of Prolene suture for duct delineation during microductectomy  

Directory of Open Access Journals (Sweden)

Full Text Available Classically, microductectomy is performed using a probe inserted via the offending duct to delineate and identify the responsible duct. We propose the use of a 1-0 Prolene (Polypropene blue monofilament nonabsorbable suture to cannulate the relevant duct.

Jayant Sharad Vaidya

2011-04-01

226

[Application of early sutures in complex treatment of purulent wounds].  

Science.gov (United States)

The examination and treatment of 841 patients with purulent diseases and acute purulent surgical diseases of soft tissues included 486 patients (control group) treated by a traditional (open) method and 355 patients (main group) treated by complex methods using early sutures. The primary suture was used in 124 patients. The average number of bed-days in this group of patients was (11.5 +/- 0.2) days. The primary delayed suture was used in 192 patients--the average number of bed-days was (12.8 +/- 0.1) days. The early secondary suture was used in 27 patients--the average number of bed-days was (17.3 +/- 0.4) days. In 327 (92.1%) cases of the main group patients the healing of the wounds by primary intention was obtained with good functional and cosmetic results which allowed to make the period of hospital treatment at an average 12.2 days shorter. PMID:12942617

Sto?ko, Iu M; Melekhov, P A; Smekhov, S Iu

2003-01-01

227

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

1989-01-01

228

Suture-Related Keratitis Caused by Corynebacterium macginleyi?  

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We report two cases of suture-related keratitis following penetrating keratoplasty. In both cases, Corynebacterium macginleyi was isolated from corneal specimens. Scanning electron microscopy revealed that corynebacteria could aggregate and form a biofilm. The MICs of sulbenicillin and fluoroquinolones were high for both isolates. Our findings show that C. macginleyi can cause keratitis with biofilm formation.

Suzuki, Takashi; Iihara, Hirotoshi; Uno, Toshihiko; Hara, Yuko; Ohkusu, Kiyofumi; Hata, Hiroyuki; Shudo, Masachika; Ohashi, Yuichi

2007-01-01

229

Cranial suture biology and dental development: genetic and clinical perspectives.  

Science.gov (United States)

Premature fusion of the calvarial bones at the sutures, or craniosynostosis (CS), is a relatively common birth defect (1:2000-3000) frequently associated with limb deformity. Patients with CS may present oral defects, such as cleft soft palate, hypodontia, hyperdontia, and delayed tooth eruption, but also unusual associations of major dental anomalies such as taurodontism, microdontia, multiple dens invaginatus, and dentin dysplasia. The list of genes that are involved in CS includes those coding for the different fibroblast growth factor receptors and a ligand of ephrin receptors, but also genes encoding transcription factors, such as MSX2 and TWIST. Most of these genes are equally involved in odontogenesis, providing a pausible explanation for clinical associations of CS with dental agenesis or tooth malformations. On the basis of the present knowledge on genes and transcription factors that are involved in craniofacial morphogenesis, and from dental clinics of CS syndromes, the molecular mechanisms that control suture formation and suture closure are expected to play key roles in patterning events and development of teeth. The purpose of this article is to review and merge the recent advances in the field of suture research at the genetic and cellular levels with those of tooth development, and to apply them to the dental clinics of CS syndromes. These new perspectives and future challenges in the field of both dental clinics and molecular genetics, more in particular the identification of possible candidate genes involved in both CS and dental defects, are discussed. PMID:17686002

De Coster, P J; Mortier, G; Marks, L A; Martens, L C

2007-09-01

230

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

231

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)

2011-12-01

232

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

2014-02-15

233

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)

1978-10-01

234

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

235

A preliminary study of oil-polypropylene insulating system  

Energy Technology Data Exchange (ETDEWEB)

In this paper, creeping discharge of oil-polypropylene insulating system have been studied using an experimental model with the flowing oil under ac voltage. The ac creeping discharge inception voltage of the oil-polypropylene system has been tested under varied conditions. According to the experimental results, all of the oil temperature, the oil flow rate and the position of poly-propylene film can influence the ac creeping discharge inception voltage of oil-polypropylene system. The ac inception voltage of this system is increased along with the increase of oil temperature and oil flow rate. Moreover, the ac inception voltage is higher at the position near to oil entrance than that at the position far to oil entrance. Considering the experimental results, a new composite insulating system is put forward for reducing the negative effects of streaming electrification in larger power devices with forced-oil cooling systems.

Chi Xiaochun; Ding Lijian; Yang Jiaxiang [Harbin Inst. of Electrical Technology (China). Dept. of Electrical Materials Engineering

1996-12-31

236

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

237

The shape memory effect in 50.3Mn-39.7Ni-10.0Al alloy  

International Nuclear Information System (INIS)

The shape memory effect has been observed in 50.3Mn-39.7Ni-10.0Al alloy by thermal cycling under a load and bending at room temperature. A particular apparatus for bending tests is described. The second phase particles improve ductility of the intermetallic but result in incomplete shape recovery. Deformation of a dual phase material consisting the hard intermetallic matrix and the particles of the soft disordered phase is discussed. (orig.)

1995-12-01

238

Polypropylene/graphite nanocomposites by in situ polymerization  

International Nuclear Information System (INIS)

This work presents the synthesis of nanocomposites of polypropylene/graphite by in situ polymerization using metallocene catalyst and graphene nanosheets. Initially was analyzed which of the metallocene catalysts rac-Et(Ind)2ZrCl2 or rac-Me2Si(Ind)2ZrCl2 produces polypropylene with mechanical properties more relevant. Then it were performed the in situ polymerization reactions to obtain the nanocomposites. The polymeric materials were characterized by XRD, DSC, GPC and DMTA. (author)

2011-10-16

239

Composites on the Basisof Discrete Woven Filler and Polypropylene  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Possibility of fabrication by the method of extrusion of composite on the basis of polypropylene and discrete filler in the form of the grinded fabric is studied. Influence on physical-mechanical properties and water absorption of obtained materials for the fillers of various chemical nature - fabrics on the basis of synthetic or/and natural fibers, their filling degree in polypropylene, as well as dependences of these properties on pre-award dressing of filler is estimated. ...

Surovtcev, Alexander; Sporjagin, Edward

2009-01-01

240

Surface and mechanical properties of polypropylene/clay nanocomposite  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Huge consumption of polypropylene in the industries like automotive motivates academic and industrial R&Ds to find new and excellent approaches to improve the mechanical properties of this polymer, which has no degradation effect on other required performance properties like impact resistance, controlled crystallinity, toughness and shrinkage. Nowadays, nanoparticles play a key role in improving the mechanical and surface properties of polypropylene. In this study, three compositions of...

Dibaei Asl Husein; Abdouss Majid; Torabi Angaji Mahmoud; Haji Aminoddin

2013-01-01

 
 
 
 
241

Improved gas-phase polypropylene process is efficient  

Energy Technology Data Exchange (ETDEWEB)

This article presents a gas phase polypropylene process that is both versatile and simple. The inherent simplicity allows close control of critical polymer properties through feed-forward control of reactor variables. In addition, the process offers reliable operation, lower energy requirements, and minimum antipollution requirements. A comparison of polypropylene processes shows that both capital and operating costs are significantly lower for the gas phase process than for the best available competitive process.

1984-11-05

242

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

2006-01-01

243

Environmental and Cost Assessment of a Polypropylene Nanocomposite  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper describes a study on the use of a polypropylene (PP)/layered silicate nanocomposite as packaging film, agricultural film, and automotive panels. The study’s main question was “Are the environmental impacts and costs throughout the life cycle of nanocomposite products lower than those of products manufactured from conventional materials?” The conventional (benchmark) materials studied were pure polypropylene as packaging film, pure polyethylene as agricultural film, and glass ...

2007-01-01

244

Synthesis of Polypropylene Fiber/Hydrated Iron Oxide Nanocomposite Adsorbent  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 (7...

2013-01-01

245

Altering surface characteristics of polypropylene mesh via sodium hydroxide treatment.  

Science.gov (United States)

Incisional hernias represent a serious and common complication following laparotomy. The use of synthetic (e.g. polypropylene) meshes to aid repair of these hernias has considerably reduced recurrence rates. While polypropylene is biocompatible and has a long successful clinical history in treating hernias and preventing reherniation, this material may suffer some limitations, particularly in challenging patients at risk of wound failure due to, for example, an exaggerated inflammation reaction, delayed wound healing, and infection. Surface modification of the polypropylene mesh without sacrificing its mechanical properties, critical for hernia repair, represents one way to begin to address these clinical complications. Our hypothesis is treatment of a proprietary polypropylene mesh with sodium hydroxide (NaOH) will increase in vitro NIH/3T3 cell attachment, predictive of earlier and improved cell colonization and tissue integration of polypropylene materials. Our goal is to achieve this altered surface functionality via enhanced removal of chemicals/oils used during material synthesis without compromising the mechanical properties of the mesh. We found that NaOH treatment does not appear to compromise the mechanical strength of the material, despite roughly a 10% decrease in fiber diameter. The treatment increases in vitro NIH/3T3 cell attachment within the first 72 h and this effect is sustained up to 7 days in vitro. This research demonstrates that sodium hydroxide treatment is an efficient way to modify the surface of polypropylene hernia meshes without losing the mechanical integrity of the material. This simple procedure could also allow the attachment of a variety of biomolecules to the polypropylene mesh that may aid in reducing the complications associated with polypropylene meshes today. PMID:22337661

Regis, Shawn; Jassal, Manisha; Mukherjee, Nilay; Bayon, Yves; Scarborough, Nelson; Bhowmick, Sankha

2012-05-01

246

Analysis of the fracture behavior of polypropylene: sawdust composites  

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Natural fiber reinforced composite is an emerging area in Polymer science. The use of lignocellulosic materials in thermoplastic composites may contribute to reduce the waste of vegetal biomass. The natural fibers are biodegradable, low cost materials having density and specific properties comparable to those of conventional fiber composites. In this work composites of polypropylene (PP) plus maleated polypropylene (MAPP) filled with sawdust were prepared under fixed processing conditions (mi...

2005-01-01

247

Synthesis and Modification of Polypropylene by Radiation-induced Grafting  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Polypropylene fiber (PP) was radiation-induced graft polymerization of lauryl acrylate (LA) and butyl acrylate (BA)using a 60Co gamma radiation source. Then the grafted polypropylene fiber was characterized by a Fourier transforminfrared (FT-IR) spectrometer, Scanning Electron Microscopy (SEM), differential scanning calorimetry (DSC) andthermogravimetry (TG), which indicated that LA and BA have been grafted onto PP. The article focused on somefactors that influenced on...

2009-01-01

248

Study on the Dynamic Performance of Polypropylene Fiber Reinforced Concrete  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2013-01-01

249

Viscoelasticity, viscoplasticity, and creep failure of polypropylene/clay nanocomposites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Observations are reported on polypropylene/clay nanocomposites in tensile tests with various strain rates, relaxation tests at various strains, and creep tests with various stresses at room temperature. New constitutive equations are derived in viscoelasticity and viscoplasticity of nanocomposites. Adjustable parameters are found by fitting the experimental data. The stress-strain relations are applied to the analysis of creep rupture. It is demonstrated that reinforcement of polypropylene wi...

2009-01-01

250

The fire resistance of concrete with polypropylene fibers  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents the results and conclusions of an experimental study characterization performed on the polypropylene fibers for use in concretes (NPC, Normal Performance Concrete to produce an improvement in the durability against exposure to high temperatures. It was used only one type of polypropylene fiber with two different lengths, 6?mm and 12?mm, to evaluate the effect of the length.

Corpas F.A.

2013-09-01

251

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

252

Strategies for improving mechanical properties of polypropylene/cellulose composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

253

Vaginal Vault Closure Techniques in total Laparoscopic Hysterectomy: A Comparison between Laparoscopic Route Vault Suturing and Vaginal Route Suturing  

Directory of Open Access Journals (Sweden)

Full Text Available Objective: To study and compare the two approaches for vaginal vault closure in patients undergoing total laparoscopic hysterectomy. Material and methods: A comparative study was undertaken in 70 patients who underwent total laparoscopic hysterectomy for benign gynaecological disorders in Kesar SAL medical college, Ahmedabad. In half of the patients, vault closure was done through laparoscopic route and in the other half it was done through vaginal route. Results: The group who underwent vaginal vault suturing by laparoscopic route, the mean operative time was 77.0 ( +6.4 SD, range 70-94 minutes as compared to the group in which vaginal vault were sutured through vaginal route (88.5 minutes with a SD +4.9, range 80 - 100, the observed difference was statically significant (p <0.00. The post operative vaginal length was better preserved in laparoscopic suturing (8.4 cm with a SD of +0.4, range 8.5 - 10 as compared to vaginal suturing (7.34 cm with a SD of + 0.4, range 7.5 – 9.2 and difference was statically significant (p <0.00. Post operative complications were also statically significantly lower in the laparoscopic route vault closure(28.5% as compared to vaginal route vault closure(88.5% and difference was statically significant (Z= 6.42, p < 0.000. Conclusion: laparoscopic route vault closure was less time consuming and comparatively safer than vaginal route vault closure.

Kanupriya Singh, Bhavit Shah, Vipul Patel, Mihir Goswami, M B Shah

2011-01-01

254

Functionalized polypropylenes as efficient dispersing agents for carbon nanotubes in a polypropylene matrix; application to electromagnetic interference (EMI) absorber materials  

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Carbon nanotubes (CNTs) have been dispersed within polypropylene with the purpose to prepare electromagnetic interference (EMI) absorbers. In order to limit the reflectivity of the electromagnetic waves at the interface of the materials while achieving good absorbing properties, the CNTs concentration must be kept low (<3 wt%) which means that a perfect dispersion must be ensured. Since CNTs do not disperse well within apolar polymer matrices such as polypropylene, two compatibilizers bearing...

Thomassin, Jean-michel; Huynen, Isabelle; Je?ro?me, Robert; Detrembleur, Christophe

2010-01-01

255

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

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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...

2011-01-01

256

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

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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

257

Compatibilisation of Polypropylene/Ethylene Propylene Diene Terpolymer/Kaolin Composites: The Effect of Maleic Anhydride-Grafted-Polypropylene  

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The tensile properties and morphology of polypropylene (PP)/ethylene propylene diene terpolymer (EPDM)/Kaolin composites were investigated. Maleic anhydride-grafted-polypropylene (MAPP) was used as a compatibiliser to improve the compatibility of kaolin filled PP/EPDM composites. Results show that incorporation of MAPP increased the tensile strength and Young’s modulus, but reduced the elongation at break. Scanning electron microscopy (SEM) of the tensile fracture surfaces of composites ind...

2009-01-01

258

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

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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

259

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

260

The global impact of sutures assessed in a finite element model of a macaque cranium.  

Science.gov (United States)

The biomechanical significance of cranial sutures in primates is an open question because their global impact is unclear, and their material properties are difficult to measure. In this study, eight suture-bone functional units representing eight facial sutures were created in a finite element model of a monkey cranium. All the sutures were assumed to have identical isotropic linear elastic material behavior that varied in different modeling experiments, representing either fused or unfused sutures. The values of elastic moduli employed in these trials ranged over several orders of magnitude. Each model was evaluated under incisor, premolar, and molar biting conditions. Results demonstrate that skulls with unfused sutures permitted more deformations and experienced higher total strain energy. However, strain patterns remained relatively unaffected away from the suture sites, and bite reaction force was likewise barely affected. These findings suggest that suture elasticity does not substantially alter load paths through the macaque skull or its underlying rigid body kinematics. An implication is that, for the purposes of finite element analysis, omitting or fusing sutures is a reasonable modeling approximation for skulls with small suture volume fraction if the research objective is to observe general patterns of craniofacial biomechanics under static loading conditions. The manner in which suture morphology and ossification affect the mechanical integrity of skulls and their ontogeny and evolution awaits further investigation, and their viscoelastic properties call for dynamic simulations. PMID:20652940

Wang, Qian; Smith, Amanda L; Strait, David S; Wright, Barth W; Richmond, Brian G; Grosse, Ian R; Byron, Craig D; Zapata, Uriel

2010-09-01

 
 
 
 
261

New polypropylene materials and hotmelt adhesives; Neue Strukturmaterialien und Schmelzklebestoffe auf Polypropylenbasis  

Energy Technology Data Exchange (ETDEWEB)

Polypropylene combines attractive price/performance ratio with versatility in applications and recycling. Today polypropylene is entering successfully higher-value-in-use engineering resin markets, substituting other, environmentally less friendly plastics. Polypropylene`s success results from recent breakthroughs in catalyst and process technology as well as recycling. Novel generations of tailor-made catalysts give excellent control on molecular architectures and polymer properties in solvent-free gas phase polymerization. Metallocene catalysts offer new opportunities for polypropylene. On the basis of new intermediates produced in metallocene-catalyzed propene polymerization hotmelt adhesives for polypropylene bonding were formulated without requiring polypropylene surface pretreatments. New reactive processing technologies are the key to novel multiphase polypropylene blends and hybridcomposites exhibiting improved toughness/stiffness balance. (orig.) [Deutsch] Polypropylen kombiniert attraktives Preis/Leistungs-Verhaeltnis mit Vielseitigkeit in Anwendungen und Recycling, substituiert erfolgreich andere, weniger umweltvertraegliche Kunststoffe und dringt in Bereiche der hoeherwertigen Konstruktionswerkstoffe ein. Grundlagen fuer den Erfolg von Polypropylen sind Innovation in Katalysatortechnologie, Verfahrenstechnik, Verarbeitung und Wiederverwertung. Ueber massgeschneiderte Katalysatorsysteme koennen in emissionsarmen Gasphasenverfahren molekularen Architekturen und Produkteigenschaften von Polypropylen gesteuert werden. Metallocen-Katalysatoren eroeffnen neue Chancen fuer Polypropylen. Mit Zwischenprodukten aus der Metallocen-Katalyse koennen Schmelzklebstoffe fuer das Verkleben von Polypropylen ohne Oberflaechenvorbehandlung formuliert werden. Neue Konzepte fuer die Reaktionsextrusion eroeffnen den Zugang zu Multiphasen-Polypropylenblends und Hybridcompositen, die sich durch verbesserte Steifigkeits/Zaehigkeits-Bilanz auszeichnen. (orig.)

Muelhaupt, R. [Freiburger Materialforschungszentrum der Albert-Ludwigs-Universitaet, Freiburg im Breisgau (Germany); Setz, S.; Thomann, R.; Kressler, J.; Roesch, J.

1995-12-31

262

HUESOS SUTURALES EN EL PTERION SUTURAL BONES IN THE PTERION  

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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

263

Patella fracture after medial patellofemoral ligament reconstruction using suture anchors.  

Science.gov (United States)

The medial patellofemoral ligament (MPFL) acts as a soft tissue restraint to lateral subluxation of the patella, and is frequently damaged following patellar dislocation. A number of techniques for repair or reconstructions of the MPFL have been reported. We report two cases of patellar fracture following MPFL reconstruction utilizing suture anchors and bone tunnels that do not completely traverse the patella. The first case occurred seven months after surgery and the second case was at six weeks following surgery. There have been previous reports of patellar fracture following MPFL reconstruction, particularly when patellar tunnels completely traverse the patella. The authors decided to use suture anchors to reduce the risk of patellar fracture, and they feel that the fractures reported in this paper resulted from surgical error rather than system error. We feel that this is an important learning point when initially using this technique, and should be disseminated to other surgeons who undertake this surgery. PMID:23916510

Dhinsa, Baljinder Singh; Bhamra, Jagmeet Singh; James, Chris; Dunnet, William; Zahn, Helmut

2013-12-01

264

HUESOS SUTURALES EN EL PTERION / SUTURAL BONES IN THE PTERION  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish 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.

265

Comparison of bursting pressure of sutured, stapled and BAR anastomoses.  

Science.gov (United States)

The study was undertaken to compare anastomotic bursting pressure (ABP) of colorectal canine anastomoses using three different anastomotic techniques. Biofragmentable anastomotic ring (BAR), stapled, and sutured colon anastomoses were sequentially placed in each of 48 dogs following division of the colon at three equally spaced sites. Four groups of 12 dogs were sacrificed either on day 0, 3, 7, or 28 and ABP and bursting wall tension were determined. The data revealed that BAR anastomoses have the greatest strength on the day of surgery, sutured anastomoses are the strongest on the third day and all are comparable by the 7th day. Bursting pressures for all groups by day 28 approach normal colonic bursting pressure, with any differences likely to be a reflection of variation in anastomotic fibrosis and other factors. PMID:8492037

Bundy, C A; Jacobs, D M; Zera, R T; Bubrick, M P

1993-03-01

266

Facial Asymmetry Correction in Facial Palsy Patients with Silhouette Sutures  

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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

267

A Case of Intraluminal Endoscopic Suturing of Gastric Perforation  

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Full Text Available Recent endoscopic equipment development enabled to diagnose premalignant conditions and early gastric and colon cancer resulting in the rise of new methods of endoscopic treatment — endoscopic mucosal resection and endoscopic submucosal dissection. The advantages of such operation are obvious — minimal invasion, organ function preservation, a reduced hospitalization period, though these interventions carry the risk of iatrogenic complications (bleeding, perforation. Perforation is the most dangerous complication requiring immediate laparotomy. The authors have described a case of successful application of endoscopic suturing device to manage gastric wall iatrogenic perforation resulted from endoscopic submucosal dissection for submucous gastric tumor. The defect was closed using Apollo Overstitch endoscopic suturing device (USA avoiding laparotomy. The postoperative period was uneventful, and the patient was discharged 5 days after surgery.

S.V. Kantsevoy

2014-06-01

268

Impact fragmentation of polyurethane and polypropylene cylinder  

Science.gov (United States)

The impact fragmentation of a bulk polyurethane elastomer (PU) and polypropylene (PP) cylinder have been investigated using a Cu plate projectile launched by a propellant gun at a velocity of 0.53-1.4 km/s. A projectile drills into a PU sample and forms a cavity in the sample. A small number of tiny fragments are formed. When the projectile smashes in at 1.4 km/s, the PU cylinder bursts and PU fragments form. On the other hand, a brittle fracture occurs on the PP cylinder. The mass of fragments from the PU sample generated at a lower impact velocity is distributed in the lognormal form, whereas the mass of fragments from the PU sample generated by a 1.4 km/s impact follows a power-law distribution. The fragment mass distribution of the PP sample generated at a lower impact velocity obeys the power-law form, whereas that generated at a higher impact velocity follows the lognormal form.

Kishimura, Hiroaki; Noguchi, Daisuke; Preechasupanya, Worrayut; Matsumoto, Hitoshi

2013-11-01

269

Nature of peroxy radicals in polypropylene  

International Nuclear Information System (INIS)

Recent ESR studies on structure, motional character and decay reaction of peroxy radicals in irradiated polypropylene, which were made in our group, were summarized. Peroxy radicals must be trapped at the sites with various conformations and mobilities, in principle. However, we took an approximate consideration that the sites can be divided into two kinds, mobile and immobile. This interpretation was very successful in making good simulation procedures of ESR spectra. Internal rotation angles, which represent the orientations of the O-O group around C-O bond with respect to the adjacent C-C bond, both for mobile and immobile radicals were determined. The structure of the site for immobile radicals was found to be corresponding to gauche type and that for mobile one was found to be corresponding to skew type. Motional character of the peroxy radicals was found to be a rotation or rotational vibration around main chain axis. Decay reaction of the mobile peroxy radicals were interpreted by a diffusion controlled mechanism and the interpretation that immobile radicals do not take place in the decay reaction was reflected in the analysis. (author)

1991-01-01

270

Polypropylene and silica short fibers composites  

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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

271

Magnetic fluids stabilized by polypropylene glycol  

Science.gov (United States)

A series of samples of magnetic fluids stabilized with low-molecular weight polypropylene glycol (PPG) of different molecular masses were synthesized. The use of PPG allowed the maximum extension of the carrier fluid range to include ethyl- and butyl-acetate, ethanol, butanol, acetone, carbon tetrachloride, toluene, kerosene and PPG itself. Magnetic and rheological properties of the samples were investigated. Based on the results of investigation it has been concluded that magnetic nanoparticles are covered by a monolayer of surfactant molecules. At low temperatures the propanol-based sample preserves fluidity up to -115 °C. Measurement of critical temperatures of other base fluids showed that alcohols are the best carrier medium. Coagulation stability of the ethanol-based ferrocolloid with respect to water and kerosene was explored. It has been found that kerosene, whose fraction by weight exceeds 22.5%, does not mix with the colloid. This effect can be used to produce magneto-controllable extractors of ethyl alcohol. Under the action of water the colloid coagulates, which allows one to substitute the carrier fluid and to separate the colloid into fractions.

Lebedev, A. V.; Lysenko, S. N.

2011-05-01

272

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.

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

273

Polypropylene matrix composites reinforced with coconut fibers  

Directory of Open Access Journals (Sweden)

Full Text Available 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 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

2011-09-01

274

Mobility as a mechanism for radiation stabilization of polypropylene. [Gamma radiation  

Energy Technology Data Exchange (ETDEWEB)

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.

Williams, J.L.; Dunn, T.S. (Becton, Dickinson Research Center, Research Triangle Park, NC (USA)); Stannett, V.T. (North Carolina State Univ., Raleigh (USA). Dept. of Chemical Engineering)

1982-01-01

275

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.

2012-01-15

276

Polypropylene separator for use in alkaline storage batteries and process for making same  

Energy Technology Data Exchange (ETDEWEB)

Intrinsically nonwettable polypropylene battery separators are rendered wettable by treating them with polybenzimidazole. Polybenzimidazole (Pbi) treated polypropylene (Pp) separators exhibited excellent thermal and chemical stabilities, show excellent electrolyte retention, and are gas permeable.

Verzwyvelt, S. A.

1980-08-12

277

To mesh or not to mesh with polypropylene: does carcinogenesis in animals matter?  

Science.gov (United States)

Polypropylene in sheets has been been found to be carcinogenic in some laboratory animals. Although no human carcinogenicity has been reported, long-term follow-up in humans implanted with polypropylene mesh will be important. PMID:24614954

Ostergard, Donald R; Azadi, Ali

2014-05-01

278

Effect of wollastonite and talc on the micromechanisms of tensile deformation in polypropylene composites  

International Nuclear Information System (INIS)

The work presented here describes the effect of wollastonite and talc on the micromechanisms of surface deformation and subsequent propagation into the bulk of low and high crystallinity polypropylenes during tensile straining. The potential of high resolution electron microscopy is utilized to examine deformation processes, and develop deformation mechanism maps. While mineral-reinforced polypropylenes exhibited an increase in tensile modulus, yield strength remained unaffected. Crystallization behavior indicated that the reinforcement minerals increase the rate of nucleation with consequent increase in percentage of bulk crystallinity. The reinforcement of polypropylene with wollastonite or talc alters the primary micromechanism of deformation from deformation bands/crazing in neat polypropylenes to wedge/ridge tearing in mineral-reinforced low crystallinity polypropylene composites. However, wedges were absent in high crystallinity polypropylene composites. The final fracture in reinforced polypropylene occurs by a mixed mode consisting of fibrillation and brittle mode, while crazing-tearing and brittle deformation are fracture modes for neat polypropylenes

2004-05-15

279

Effect of wollastonite and talc on the micromechanisms of tensile deformation in polypropylene composites  

Energy Technology Data Exchange (ETDEWEB)

The work presented here describes the effect of wollastonite and talc on the micromechanisms of surface deformation and subsequent propagation into the bulk of low and high crystallinity polypropylenes during tensile straining. The potential of high resolution electron microscopy is utilized to examine deformation processes, and develop deformation mechanism maps. While mineral-reinforced polypropylenes exhibited an increase in tensile modulus, yield strength remained unaffected. Crystallization behavior indicated that the reinforcement minerals increase the rate of nucleation with consequent increase in percentage of bulk crystallinity. The reinforcement of polypropylene with wollastonite or talc alters the primary micromechanism of deformation from deformation bands/crazing in neat polypropylenes to wedge/ridge tearing in mineral-reinforced low crystallinity polypropylene composites. However, wedges were absent in high crystallinity polypropylene composites. The final fracture in reinforced polypropylene occurs by a mixed mode consisting of fibrillation and brittle mode, while crazing-tearing and brittle deformation are fracture modes for neat polypropylenes.

Hadal, R.S.; Dasari, A.; Rohrmann, J.; Misra, R.D.K

2004-05-15

280

Transcutaneous Serdev Suture For Buttock’s Lift  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Nikolay Serdev

2013-01-01

 
 
 
 
281

Further genetic heterogeneity for autosomal dominant human sutural cataracts  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A unique sutural cataract was observed in a 4-generation German family to be transmitted as an isolated autosomal, dominant trait. Since mutations in the gamma-crystallin encoding CRYG genes have previously been demonstrated to be the most frequent reason for isolated congenital cataracts, all 4 active CRYG genes have been sequenced. A single base-pair change in the CRYGA gene has been shown, leading to a premature stop codon. This was not observed in 170 control individuals. However, it did ...

2003-01-01

282

Laminoplasty using Twinfix suture anchors to maintain cervical canal expansion  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Open-door laminoplasty is a commonly performed procedure for the treatment of multiple level cervical spinal stenosis. One complication of this procedure is closure of the hinge and subsequent restenosis. Twinfix suture anchor was used in laminoplasty to stabilize cervical canal expansion. 53 patients with multiple level cervical spinal stenosis underwent laminoplasty. A unilateral open-door technique was performed for the lesion level and the elevated lamina was fixed to the lateral mass usi...

2010-01-01

283

Complexity of serrated sutures of a human skull  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Objective: to reveal the variability mechanism of complexity of serrated sutures of a human skull in the correlation with cranial form. Materials and methods. Researches of 253 arches of male and female skulls of patients at the age of 1 day-105 years without signs of cranial trauma or skeletal systemic diseases with absence of morphological signs of increase of intracranial pressure. Minimal (Min) and maximal (Max) values, average arithmetic (M), a mistake of average arithmetic (m) have been...

Kochenkova ?.V.; Zaichenko A.A.; Anisimova ?.?.; Anisimov D.I.

2011-01-01

284

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.

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

2013-01-01

285

ADJUSTABLE SUTURE STRABISMUS SURGERY: A REVIEW OF 850 CASES  

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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

286

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

287

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)

1994-12-01

288

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.

2010-01-01

289

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

290

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

291

Production of high melt strength polypropylene by gamma irradiation  

Energy Technology Data Exchange (ETDEWEB)

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 {sup 60}Co 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 effect.

Lugao, A.B. [IPEN-Av. Professor Lineu Prestes 2242, 05508-000 Sao Paulo (Brazil)], E-mail: ablugao@ipen.br; Artel, B.W.H. [EMBRARAD-Av. Cruzada Bandeirante 269, 06700-000 Sao Paulo (Brazil); Yoshiga, A.; Lima, L.F.C.P.; Parra, D.F.; Bueno, J.R. [IPEN-Av. Professor Lineu Prestes 2242, 05508-000 Sao Paulo (Brazil); Liberman, S.; Farrah, M.; Tercariol, W.R. [BRASKEM-Av. Nacoes Unidas 4777, 05477000 Sao Paulo (Brazil); Otaguro, H. [IPEN-Av. Professor Lineu Prestes 2242, 05508-000 Sao Paulo (Brazil)

2007-11-15

292

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.

2010-09-01

293

Macrophage polarization in response to ECM coated polypropylene mesh.  

Science.gov (United States)

The host response to implanted biomaterials is a highly regulated process that influences device functionality and clinical outcome. Non-degradable biomaterials, such as knitted polypropylene mesh, frequently elicit a chronic foreign body reaction with resultant fibrosis. Previous studies have shown that an extracellular matrix (ECM) hydrogel coating of polypropylene mesh reduces the intensity of the foreign body reaction, though the mode of action is unknown. Macrophage participation plays a key role in the development of the foreign body reaction to biomaterials, and therefore the present study investigated macrophage polarization following mesh implantation. Spatiotemporal analysis of macrophage polarization was conducted in response to uncoated polypropylene mesh and mesh coated with hydrated and dry forms of ECM hydrogels derived from either dermis or urinary bladder. Pro-inflammatory M1 macrophages (CD86+/CD68+), alternatively activated M2 macrophages (CD206+/CD68+), and foreign body giant cells were quantified between 3 and 35 days. Uncoated polypropylene mesh elicited a dominant M1 response at the mesh fiber surface, which was decreased by each ECM coating type beginning at 7 days. The diminished M1 response was accompanied by a reduction in the number of foreign body giant cells at 14 and 35 days, though there was a minimal effect upon the number of M2 macrophages at any time. These results show that ECM coatings attenuate the M1 macrophage response and increase the M2/M1 ratio to polypropylene mesh in vivo. PMID:24856104

Wolf, Matthew T; Dearth, Christopher L; Ranallo, Christian A; LoPresti, Samuel T; Carey, Lisa E; Daly, Kerry A; Brown, Bryan N; Badylak, Stephen F

2014-08-01

294

Production of high melt strength polypropylene by gamma irradiation  

Science.gov (United States)

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 effect.

Lugão, A. B.; Artel, B. W. H.; Yoshiga, A.; Lima, L. F. C. P.; Parra, D. F.; Bueno, J. R.; Liberman, S.; Farrah, M.; Terçariol, W. R.; Otaguro, H.

2007-11-01

295

Análise das aderências resultantes da fixação de telas cirúrgicas com selantes de fibrina e sutura: modelo experimental intraperitoneal / Analysis of adhesions resulted from mesh fixation with fibrin sealant and suture: experimental intraperitoneal model  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese OBJETIVO: Comparar fixação cirúrgica de telas de polipropileno (PP) e telas de polipropileno revestido (PCD), usando fio de sutura de polipropileno e cola biológica, quanto à formação de aderências intraperitoneais. MÉTODOS: Amostra de 46 ratas Wistar, randomizadas em seis grupos: dois grupos-contro [...] le, com cinco ratas cada, que foram submetidos um à incisão medial (IM) e o outro à uma incisão em forma de U (IU); nenhum desses grupos recebeu tela. Dois grupos com tela de PP, um com dez ratas, fixada com sutura (PPF), e o outro, com seis ratas, fixada com cola biológica (PPC). E Dois grupos com tela de PCD, no primeiro, com dez animais, a tela foi fixada com sutura (PCDF), e no segundo, com dez animais, com cola biológica (PCDC). RESULTADOS: Após o prazo de 21 dias, os grupos-controle não apresentaram aderências significantes. O grupo PPC apresentou menor grau de aderência do que o grupo PPF (p=0,01). Não houve diferença entre as fixações nos grupos com PCD. CONCLUSÃO: A comparação da fixação apresentou diferença estatística significativa apenas à tela de PP, com menor grau de aderência utilizando a cola. As aderências se localizaram predominantemente nas extremidades das telas estudadas. Abstract in english OBJECTIVE: To compare surgical fixation of polypropylene mesh (PP) and coated polypropylene mesh (PCD) using polypropylene suture and fibrin glue, as for the formation of intraperitoneal adhesions. METHODS: A sample of 46 female Wistar rats were randomized into six groups: two control groups, with f [...] ive rats each, were subjected to one medial incision (MI) and the other to a U-shaped incision (UI), none of these groups received the mesh. Two groups of PP mesh, with ten rats, fixed with suture (PPF), the other with six rats, fixed with biological glue (PPC). And two groups of PCD mesh, at first, with ten animals, the mesh was fixed with sutures (PCDFs) and the second with ten animals with biological glue (PCDC). RESULTS: After 21 days, the control groups showed no significant adhesions. The PPC group showed a lower degree of adhesion than the PPF group (p = 0.01). There was no difference between the groups with PCD. CONCLUSION: Comparison of fixation was statistically different only with PP mesh, with lesser degrees of adherence when using the glue. Adhesions were predominantly located at the extremities of the meshes studied.

Montes, Juliano Hermes Maeso; Bigolin, André Vicente; Baú, Renata; Nicola, Roberto; Grossi, João Vicente Machado; Loureiro, Cláudia Juliana; Cavazzola, Leandro Totti.

296

Análise das aderências resultantes da fixação de telas cirúrgicas com selantes de fibrina e sutura: modelo experimental intraperitoneal Analysis of adhesions resulted from mesh fixation with fibrin sealant and suture: experimental intraperitoneal model  

Directory of Open Access Journals (Sweden)

Full Text Available OBJETIVO: Comparar fixação cirúrgica de telas de polipropileno (PP e telas de polipropileno revestido (PCD, usando fio de sutura de polipropileno e cola biológica, quanto à formação de aderências intraperitoneais. MÉTODOS: Amostra de 46 ratas Wistar, randomizadas em seis grupos: dois grupos-controle, com cinco ratas cada, que foram submetidos um à incisão medial (IM e o outro à uma incisão em forma de U (IU; nenhum desses grupos recebeu tela. Dois grupos com tela de PP, um com dez ratas, fixada com sutura (PPF, e o outro, com seis ratas, fixada com cola biológica (PPC. E Dois grupos com tela de PCD, no primeiro, com dez animais, a tela foi fixada com sutura (PCDF, e no segundo, com dez animais, com cola biológica (PCDC. RESULTADOS: Após o prazo de 21 dias, os grupos-controle não apresentaram aderências significantes. O grupo PPC apresentou menor grau de aderência do que o grupo PPF (p=0,01. Não houve diferença entre as fixações nos grupos com PCD. CONCLUSÃO: A comparação da fixação apresentou diferença estatística significativa apenas à tela de PP, com menor grau de aderência utilizando a cola. As aderências se localizaram predominantemente nas extremidades das telas estudadas.OBJECTIVE: To compare surgical fixation of polypropylene mesh (PP and coated polypropylene mesh (PCD using polypropylene suture and fibrin glue, as for the formation of intraperitoneal adhesions. METHODS: A sample of 46 female Wistar rats were randomized into six groups: two control groups, with five rats each, were subjected to one medial incision (MI and the other to a U-shaped incision (UI, none of these groups received the mesh. Two groups of PP mesh, with ten rats, fixed with suture (PPF, the other with six rats, fixed with biological glue (PPC. And two groups of PCD mesh, at first, with ten animals, the mesh was fixed with sutures (PCDFs and the second with ten animals with biological glue (PCDC. RESULTS: After 21 days, the control groups showed no significant adhesions. The PPC group showed a lower degree of adhesion than the PPF group (p = 0.01. There was no difference between the groups with PCD. CONCLUSION: Comparison of fixation was statistically different only with PP mesh, with lesser degrees of adherence when using the glue. Adhesions were predominantly located at the extremities of the meshes studied.

Juliano Hermes Maeso Montes

2012-12-01

297

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

298

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)

1983-07-01

299

Graft-copolymerization 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 pyrolidone, acrylonitrile, acrylic acid and acrylamide onto irradiated polypropylene fibers has been studied. Gamma 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 the melting point of the grafted fibers increased with the increase of the degree of grafting. Polypropilen 1-vinyl-2 pyrrolidone grafted fibers showed excellent dyes absorption of almost all kinds of dyes such as direct, basic, acid, reactive, dispers, and naphtol. However for polypropylene acrylic acid grafted fibers, the colour fastness to washing was found to be unsatisfactory. The colourfastness to washing for polypropylene grafted fibers was found to be fairly good for certain dyes such as v and naphtol dyes

1977-01-01

300

Gamma radiation resistance of tale-polypropylene composite materials  

International Nuclear Information System (INIS)

Samples of isostatic polypropylene mixed with 10, 20 and 30 wt.% Talc were prepared. Sample films were gamma irradiated at 10 - 300 k Gy under air. The results from DSC suggested that fine particles of Talc showed pronounced nucleating effect by increasing the rate of crystallization and thermal stability. However, Talc-filled composites did not showed radiation resistant property. Absorbance intensity of carbonyl and hydroperoxide indicated the amount of oxidative degradation were increased with increasing radiation dose but would not depend on the Talc content. Talc was found to enhance polypropylene embrittlement and to lower the mechanical properties. However at appropriate concentration of Talc and low gamma dose. It is possible to improve the mechanical properties of the composites. In the field of environmental study, Talc-filled composites of iso tactic polypropylene may be used as a degradable plastic

1996-12-01

 
 
 
 
301

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)

1982-09-19

302

On the scratch deformation of micrometric wollastonite reinforced polypropylene composites  

International Nuclear Information System (INIS)

Scratch deformation characteristics of neat and wollastonite-containing polypropylenes under identical test conditions are examined by electron microscopy and atomic force microscopy techniques. The study indicates that the severity of plastic deformation during scratch deformation in filled polypropylenes is a strong function of the debonding/detachment of wollastonite mineral particles from the polypropylene matrix. Scratch resistance is evaluated in terms of scratch hardness, scratch depth, average scratch roughness, thickness and density of the scratch tracks. Atomic force microscopy suggests the presence of a localized region surrounding the reinforcement particle that is characterized by enhanced crystal nucleation in which the local chain conformation and kinetics are likely to be different from regions that are a significant distance away from the mineral particle

2004-01-15

303

On the scratch deformation of micrometric wollastonite reinforced polypropylene composites  

Energy Technology Data Exchange (ETDEWEB)

Scratch deformation characteristics of neat and wollastonite-containing polypropylenes under identical test conditions are examined by electron microscopy and atomic force microscopy techniques. The study indicates that the severity of plastic deformation during scratch deformation in filled polypropylenes is a strong function of the debonding/detachment of wollastonite mineral particles from the polypropylene matrix. Scratch resistance is evaluated in terms of scratch hardness, scratch depth, average scratch roughness, thickness and density of the scratch tracks. Atomic force microscopy suggests the presence of a localized region surrounding the reinforcement particle that is characterized by enhanced crystal nucleation in which the local chain conformation and kinetics are likely to be different from regions that are a significant distance away from the mineral particle.

Dasari, A.; Rohrmann, J.; Misra, R.D.K

2004-01-15

304

Surface and mechanical properties of polypropylene/clay nanocomposite  

Directory of Open Access Journals (Sweden)

Full Text Available Huge consumption of polypropylene in the industries like automotive motivates academic and industrial R&Ds to find new and excellent approaches to improve the mechanical properties of this polymer, which has no degradation effect on other required performance properties like impact resistance, controlled crystallinity, toughness and shrinkage. Nowadays, nanoparticles play a key role in improving the mechanical and surface properties of polypropylene. In this study, three compositions of "Polypropylene/nanoclay", containing 0%, 2% and 5% of nanoclay were prepared in internal mixer. For characterizing the nanoclay dispersion in polymer bulk, TEM and XRD tests were used. For scratch resistance test, scratch lines were created on the load of 900 grain on sheets and SEM images were taken and compared with neat PP scratch image. Crystallinity and mechanical behavior were studied. The results showed that mechanical properties and scratch resistance of the composites have been improved.

Dibaei Asl Husein

2013-01-01

305

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 amorphous glasses and remains unchanged due to the deposition of SiOx on both substrates.

2010-06-30

306

CCMR: Synthesis and Characterization of Poly(Propylene Carbonate)  

Science.gov (United States)

The focus of this work was to synthesize and characterize poly(propylene carbonate) made from CO2 and propylene oxide. Reactions were conducted in a high-pressure Parr reactor using a double metal cyanide catalyst and a poly(propylene glycol) initiator. The polymers were analyzed using GPC and 1H NMR. It was found that increasing the mol % of initiator in the reaction decreased molecular weight without affecting carbonate percentage. It was also determined that the increase of CO2 pressure in the reaction increased the amount of carbonate units in the polymer, without affecting molecular weight.

Dallinger, Gregory C.

2004-08-17

307

Properties of antibacterial polypropylene/nanometal composite fibers.  

Science.gov (United States)

Melt spinning of polypropylene fibers containing silver and zinc nanoparticles was investigated. The nanometals were generally uniformly dispersed in polypropylene, but aggregation of these materials was observed on fiber surface and in fiber cross-sections. The mechanical properties of the resulted composite fibers with low concentration of nanometal were comparable to those for the control PP yarns. Extruded composite fibers that contained 0.72% silver and 0.60% zinc nanoparticles had outstanding antibacterial efficacy as documented by the percentage count reduction growth of Escherichia coli and Staphylococcus aureus. Fibers containing silver particles had improved antistatic properties. PMID:21156104

Gawish, S M; Avci, H; Ramadan, A M; Mosleh, S; Monticello, R; Breidt, F; Kotek, R

2012-01-01

308

POLYPROPYLENE FIBERS POTENTIALS IN THE IRAQI CEMENTITIOUS CONCRETE CONSTRUCTIONS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An experimental study is achieved to investigate the polypropylene fibers potentials on the mechanical performance of concrete constructions. It is found that an addition of 1% and 2% of polypropylene fibers to concrete mixes produces a reduction ofconcrete slump 20% and 28% respectively comparing with conventional mix (0% of polymer) and an increasing in compressive strength of (13.1 % and 19% after 7days), (8.5% and 14.3% after 28days), and (12.25% and 17.2% after 90days) respectively. Ther...

2013-01-01

309

Investigation of Mechanical Properties of Rice Straw Fibre Polypropylene Composites  

Directory of Open Access Journals (Sweden)

Full Text Available The main objective of present work is to investigate the mechanical properties of rice straw fibre reinforced polypropylene composites at different weight fractions (0%, 5%, 10%, 15%, 20% and 25% of rice straw fibre. Rice straw fibre reinforced polypropylene composites were manufactured according to ASTM standards using injection moulding technique. The developed composites were then tested for their tensile, bending and impact properties. The standard test methods ASTM-D638M for tensile properties, ASTM-D790M for flexural properties and ASTM-D256M for impact properties of rice straw fibre composites, were used.

K Sudhakar,

2014-01-01

310

Synthesis and Modification of Polypropylene by Radiation-induced Grafting  

Directory of Open Access Journals (Sweden)

Full Text Available Polypropylene fiber (PP was radiation-induced graft polymerization of lauryl acrylate (LA and butyl acrylate (BAusing a 60Co gamma radiation source. Then the grafted polypropylene fiber was characterized by a Fourier transforminfrared (FT-IR spectrometer, Scanning Electron Microscopy (SEM, differential scanning calorimetry (DSC andthermogravimetry (TG, which indicated that LA and BA have been grafted onto PP. The article focused on somefactors that influenced on the graft degree, such as the cross-linking agent concentration, monomer concentration. Theresults showed that: the degree of grafting BA reached the maximum of 20.53%, while the maximum graft degree of LAwas 29.90%.

Feng Yuan

2009-02-01

311

Production of the oxidation-resistant polypropylene track membranes  

International Nuclear Information System (INIS)

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

1999-08-24

312

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2011-01-01

313

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

314

Nonabsorbable-Suture-Induced Osteomyelitis: A Case Report and Review of the Literature  

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We are reporting a case of nonabsorbable suture-induced osteomyelitis in patient who had an open rotator cuff repair with nonabsorbable Ethibond anchor suture. Patient in this case presented with very subtle clinical features of osteomyelitis of the left proximal humerus 15 years after initial rotator cuff repair surgery. Literature had shown that deep infection following rotator cuff repairs, although rare, can be easily missed and can cause severe complications. Absorbable suture had been d...

Yeo, Cheng Hong; Russell, Nick C.; Sharpe, Tom

2012-01-01

315

A simple method to take urethral sutures for neobladder reconstruction and radical prostatectomy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

For the reconstruction of urethra-vesical anastamosis after radical prostatectomy and for neobladder reconstruction, taking adequate sutures to include the urethral mucosa is vital. Due to the retraction of the urethra and unfriendly pelvis, the process of taking satisfactory urethral sutures may be laborious. Here, we describe a simple method by which we could overcome similar technical problems during surgery using Foley catheter as the guide for the suture.

Satheesan, B.; Kathiresan, N.

2007-01-01

316

Effect of hot drawing process on physical and thermal properties of polypropylene fiber containing selective peroxide and comparison with conventional polypropylene fibers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this research, the effect of the drawing process on the physical and thermal properties of commercially available polypropylene fiber containing selective peroxide was studied. Attempts have also been made to compare this drawn fiber sample with conventional polypropylene fibers produced from reactor and with controlled rheology grades. The results showed that the drawn PP/Peroxide fiber has higher birefringence, tenacity, and initial modulus compared with that of the drawn polypropylene f...

Bahareh Kalantari; Mojtahedi, Mohammad R. M.; Shoushtari, Ahmad M.; Aminoddin Haji

2012-01-01

317

Synthesis, crystal structure, and magnetic properties of La4Co3O10+? (0.00 ? ? ? 0.30)  

International Nuclear Information System (INIS)

The effects of nonstoichiometry on the crystal structure, thermal expansion, structural phase transitions, and magnetic properties of La4Co3O10+?, 0.00 ? ? ? 0.30, have been investigated between 2 and 1000 K. Rietveld analysis of high resolution powder X-ray diffraction data reveals the crystal structure of La4Co3O10+? (Ruddlesden-Popper type phase; Lan+1ConO3n+1 with n = 3) to be slightly monoclinically distorted, space group C2/m. The monoclinic distortion increases ant eh unit cell volume decreases slightly on increasing nonstoichiometry, ?. A structural phase transition, monoclinic to tetragonal, possibly via an intermediate orthorhombic state, occurs at 840 K. Magnetic susceptibility data indicate long-range antiferromagnetic ordering below TN ? 13 K. Above 20 K there are three temperature regimes with nearly Curie-Weiss paramagnetic behavior for the magnetic susceptibility: 20--80 K, 100--450 K, 650--985 K. This indicates a temperature-induced change from a lower, possibly via an intermediate, to a higher spin configuration for CoIII comparable to that described for LaCoO3. Field-dependent magnetic susceptibility is observed for ? > 0.00 for T < 100 K

1998-11-15

318

Calculation and Determination of natural frequencies for fresh fuel transportation package set with ANSYS 10.0 software  

International Nuclear Information System (INIS)

The fresh fuel for Bushehr Nuclear Power Plant-1 is due to be transported inside special containers which are supposed to be designed to stand against vibrations and impacts in order to protect the fuel from any possible damage. In order to perform die structural dynamic analysis of the containers, while being subjected to impact of dynamic forces, it is necessary to perform the vibration analysis which will lead to the vibrational modes and their natural frequencies for the structure of the containers. The vibration opposition of the containers must be far beyond the critical resonance. The resonance frequencies about the natural frequency of the structure will cause the enhancement of the oscillation range and may be ended with its disintegration. Determination of the natural frequencies and their mode shapes can be achieved by vibration-analyzing-methods. The amount of the natural frequency of any structure depends strongly on its shape, material and its lean points, as well as the amount and the type of the loads which the structure will be subjected to. In the present research, the container of the fresh fuel of Bushehr Nuclear Power Plant-1 is simulated by ANSYSR10.0 and their ten natural frequency modes have been calculated

2009-01-01

319

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

320

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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. Abstract in english 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-ra [...] y 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.

Paiva, Lucilene B. de; Morales, Ana R.; Guimarães, Thiago R..

 
 
 
 
321

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

322

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 tech...

2011-01-01

323

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

324

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

325

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

Science.gov (United States)

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 posterior glenoid. This procedure is simple, cost-effective, and safe, avoiding the presence of both knots and suture strands in contact with the humeral head.

Tennent, Duncan; Concina, Chiara; Pearse, Eyiyemi

2014-01-01

326

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

Science.gov (United States)

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 posterior glenoid. This procedure is simple, cost-effective, and safe, avoiding the presence of both knots and suture strands in contact with the humeral head. PMID:24749039

Tennent, Duncan; Concina, Chiara; Pearse, Eyiyemi

2014-02-01

327

Biologic response to orthopedic sutures: a histologic study in a rabbit model.  

Science.gov (United States)

Biologic reactivity to suture materials can have an effect on patient outcomes. The goal of this study was to determine the histologic response to 8 commonly used orthopedic sutures--Ethibond (Ethicon, Somerville, New Jersey), Ticron (Tyco, Waltham, Massachusetts), HiFi (Linvatec, Largo, Florida), Ultrabraid (Smith & Nephew, Memphis, Tennessee), MaxBraid (Biomet, Warsaw, Indiana), Orthocord (Mitek, Raynham, Massachusetts), MagnumWire (Opus Medical, San Juan Capistrano, California), and FiberWire (Arthrex, Naples, Florida)--using a rabbit model. The suture granuloms were evaluated at 30, 60, and 120 days with measurement of the fibrous capsule, the number of giant cells in and near the capsule, and the overall inflammatory grade: 1 (mild), 2 (moderate), and 3 (severe). MagnumWire and Ticron sutures initiated a more intense inflammatory reaction when compared to the other sutures. By 120 days, MagnumWire (P=.0297) and Ticron (P=.1855) had fewer giant cells at the soft tissue-suture interface, fewer giant cells within the capsule (P=.0074 and P=.0377, respectively), and the greatest capsular thickness of all suture types (P<.0001 and P=.1378, respectively). Differences exist between the biologic reactivity of commonly used orthopedic sutures that may be attributable to their material composition and/or braid characteristics. In comparison to other high-strength sutures, MagnumWire and Ticron stimulated a more intense foreign body inflammatory response. PMID:19902886

Carr, Brian J; Ochoa, Leah; Rankin, David; Owens, Brett D

2009-11-01

328

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

329

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

330

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).

2009-06-15

331

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 composites. Scanning electron microscopy micrograph proved that the interfacial region of treated composite board shows good interaction among kenaf’s wood fiber and PP components.

Mohamad Jani Saad

2011-09-01

332

Evaluation of healing prosthetic materials polyester mesh resorbable film and collagen elastin matrix /polypropylene used in rabbits abdominal wall defects Avaliação da cicatrização da tela de poliéster com lâmina absorvível e a tela de colágeno-elastina/polipropileno utilizadas no reparo de lesões da parede abdominal de coelhos  

Digital Repository Infrastructure Vision for European Research (DRIVER)

PURPOSE: To compare polyester with absorbable layer prosthesis with collagen-elastin/polypropylene prosthesis in the repair of abdominal wall defects. METHODS: The 16 studied rabbits were divided in groups A and B (euthanized on the 30th and 60th days, after the implant of the mesh). The animals underwent laparotomy and received a 2cm wall "defect" on each side of the Alba linea. The repair was made with the suture of a polyester mesh with absorbable film on the left side of the Alba Linea an...

Danielle Duck Schulz; Nicolau Gregori Czeczko; Osvado Malafaia; Gustavo Justo Schulz; Czeczko, Leticia Elizabeth A.; Larissa Santin Garcia; Ulrich Andreas Dietz

2009-01-01

333

Bone suture in management of mandibular degloving injury.  

Science.gov (United States)

Traumatic degloving injuries of the mandible are rare intraoral soft tissue traumas. A simple review of the medical literature shows that no article up to this date has reported the prevalence of the degloving injuries of the mandible. Moreover, the highest incidence of mandibular degloving injuries is reported in children and young adults. In this article, the author describes the mandibular degloving injury, characterized by the separation of periosteum and soft tissues of the anterior buccal side of the mandible, and the bone suture technique. This article outlines that a correct diagnostic assessment and appropriate treatment plan can reduce the complications after mandibular degloving injuries. PMID:24470849

Rahpeyma, Amin; Khajeahmadi, Saeedeh

2013-01-01

334

Internal fixation strength of suture anchors--update 1997.  

Science.gov (United States)

Two new areas of anchor development are biodegradable anchors and "mini" anchors. The group of biodegradable anchors tested include the Bio-Anchor, LactoSorb, Biofix, Bio-Statak, Mini Screw suture anchor, DePuy 4.5 molded, DePuy 4.5 machined, DePuy 3.5 machined, TAG Wedge 4, TAG Rod 2, TAG Wedge 3, TAG Wedge 2, and Stealth. "Mini anchors" have drill holes or minor diameters of Anchor, miniHarpoon, mini Mitek and Fast in 3, Statak 1.5 and 2.5, SB 2 and PeBA 3, Corkscrew 5, Corkscrew 3.5, and Fastak A2, Ogden 2.5, TAG Wedge 2, ROC 1.9, and Questus 2.5. Additional anchors tested that fit neither category include the Anspach, Questus 3.5 and 5.0, SB 3 and PeBA-C, Ogden 3.5, Fast in 4, Ultrafix, and the ROC 3.5, ROC 2.8, ROC 2.3, and ROC XS. An anchor comparison, using an established protocol in fresh porcine femurs, recorded failure strength, failure mode, eyelet size, minor and major diameters, and drill hole sizes. Except for the Bio-Anchor and TAG Wedge 2, biodegradable anchors tend to be larger to compensate for their lower strength relative to metal. Biodegradable screw anchors' predominant failure mode was eyelet cutout, whereas biodegradable nonscrew anchors failed to predominantly by anchor pullout. From an initial mechanical perspective, these biodegradable anchors perform acceptably. Both biodegradable and "mini" anchors include screw and nonscrew designs. As expected, screw designs perform well and generally fail at higher loads than nonscrew anchors. Although biodegradable anchors, as a group, are not as strong as metal anchors, they are stronger than the sutures for which they are designed. The move to smaller ("mini") and biodegradable anchors is supported by these data. Whether an anchor fails at twice the suture breaking strength or 10 times the suture breaking strength should make no difference. PMID:9195034

Barber, F A; Herbert, M A; Click, J N

1997-06-01

335

Suture Retention Strength of Expanded Polytetrafluoroethylene (ePTFE) Graft  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Our meticulous investigation of ePTFE graft breakage when a wire placed at the edge of an ePTFE graft was pulled, revealed that, depending on the breakage pattern, a break starts much earlier than the peak suture retention strength, which is the current international indicator for anastomotic-site break strength. Furthermore, the breakage patterns differ based on the thickness of the wire and the fiber direction of the ePTFE graft. Based on these findings, we advocate measuring the p...

2010-01-01

336

Near-surface deformation in polypropylene blends  

Science.gov (United States)

Polypropylene blends with up to 20% rubber phase are known as thermoplastic polyolefin or TPO and have been widely used in the automotive industry in both painted and unpainted components. Poor scratch resistance and paint adhesion have been of great concern for TPO applications. The research described in this thesis has addressed both of these issues by studying the near-surface deformation under scratches in unpainted TPO, and the interfacial adhesion and deformation of painted TPO. A transmission electron microscopy approach has been developed to study the microstructure and microdeformation in this important class of engineering materials. It was observed that highly oriented near-surface material in injection-molded TPO plastically deformed by forming periodic shear bands under scratches. The material inside the shear band dilated as revealed by the difference in the angles between the shear band boundary and the rubber particles inside and outside the shear bands. The extent of material dilation inside the shear bands decreased with the distance from the free surface and increased with normal applied load. At high applied normal loads (>400 g), a significant amount of voiding caused by the debonding between the rubber phase and the PP matrix was observed. Talc particles were found to preferentially wet the rubber phase and this may prevent debonding between talc particles and the PP matrix as observed in talc-filled pure PP. The anisotropy in scratching behavior correlates with the anisotropy in mechanical properties. The morphology of the scratching deformation was found to be particularly sensitive to the near-surface structural anisotropy. A tensile cracking test was applied to quantitatively measure the interfacial adhesion between paint and TPO substrates. Interfacial structure between chlorinated polyolefin adhesion promoter and TPO substrate was studied by electron microscopy. The swelling of the rubber phase near the interface was observed, evidently arising from the interaction with the solvent in the paint and adhesion promoter. Diffusion of the rubber phase near the interface was also observed. Baking at high temperature enhanced both the swelling and interfacial diffusion of rubber phase. Paint adhesion was improved in TPO substrates with lower molecular weight PP homopolymer, which was ascribed to the enhanced interfacial diffusion.

Tang, Honxiang

337

CRUDE PALM OIL AS A BIOADDITIVE IN POLYPROPYLENE BLOWN FILMS  

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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

338

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)

2011-10-16

339

Mechanical and Morphological Properties of Polypropylene/Polyoxymethylene Blends  

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This work studies the mechanical and morphological properties of polypropylene (PP)/polyoxymethylene (POM) blends. The PP/POM blends were prepared by melting-blend with an internal mixer. The contents of PP were used at 10%, 20%, 30%, 70%, 80% and 90% by weight. The phase morphology of the blends was observed by scanning electron microscope (...

Sirirat Wacharawichanant; Tanakorn Siripattanasak

2013-01-01

340

The effects of normal paraffins mobilizers on irradiated polypropylene  

International Nuclear Information System (INIS)

The n-paraffins blended with polypropylene (PP) as mobilizer had been investigated. The effectiveness of mobilizer (n-paraffins) on irradiated polypropylene is dependent on the molecular weight of mobilizer and its content on polypropylene. The n-docosame (n-C_2_2) possesses the best effectiveness of radiation tolerance on PP among the mobilizer paraffins: n-decane (n-C_1_0), n-hexadecane (n-C_1_6), n-docosane (n-C_2_2) and n-hexatriacontane (n-C_3_6). The 2% (w/w) content of a given mobilizer is the most effective at reducing the embrittlement of irradiated PP as evidenced by the elongation at break. The physical properties of polypropylene with mobilizers such as density, Young's modulus, the Fraction of free volume and the weight swelling ratio in p-xylene at room temperature were measured. Above phenomena are related with the constructive of blended PP and demonstrated by its physical properties

1995-11-20

 
 
 
 
341

Investigation of polypropylene fiber effect to the silica fume concrete  

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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

342

Colorimetry analysis of polypropylene-polyethylene base copoliners  

International Nuclear Information System (INIS)

In this paper, crystallisation process study has been performed, from the molten material, in polypropylene-polyethylene (PP-PE) copolymers rich in PP (? 95 wgh.%), using different additives. Some samples have been artificially aged. Calorimetric analysis has been performed by different scanning calorimetry (DSC), from which crystallisation kinetics has been studied under dynamic conditions. (Author) 22 refs

1998-01-01

343

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)

1985-04-01

344

Strength of different Krackow stitch configurations using high-strength suture.  

Science.gov (United States)

The purpose of the present study concerning high-strength sutures was to determine whether increasing the number of locking loops with different size sutures or decreasing the suture size with increased suture strands would have any influence on the strength of Achilles tendon repair. A total of 32 fresh bovine Achilles tendon specimens were randomly assigned to 4 groups. For 3 of the groups, 1 suture was used (no. 2 or no. 5 FiberWire™ with 2 or 4 Krackow locking loops). For the fourth group, 2 sutures (2-0 FiberWire™) with 2 locking loops were used. After repair, the study groups underwent cyclic loading (0 to 200 N, 200 cycles) and then underwent tension to failure in a testing machine. Cyclic elongation, peak to peak displacement, ultimate load, stiffness, and failure mode were recorded for each specimen. The tendon width and thickness were measured in all specimens. The mean width, thickness, cyclic displacement, load to failure, and pull-out stiffness showed no differences among the 4 groups. The cyclic peak to peak displacements (0.01 ± 0.01 mm) were smallest with the no. 5 suture with 4 locking loops (p < .05), with no failure during cyclic loading, unlike in the other groups. In the group with 2-0 suture with 4 strands and 2 locking loops, 6 failed during cyclic loading. The number of locking loops used might have had an influence on the strength of the Krackow suture configuration using the larger diameter, high-strength sutures. However, decreasing the suture diameter, with a simultaneous increase in the number of strands, failed to improve the initial strength of the repair. PMID:23611415

Hapa, Onur; Erduran, Mehmet; Havitçio?lu, Hasan; Çeçen, Berivan; Ak?ahin, Ertu?rul; Güler, Serkan; Atalay, Ka?an

2013-01-01

345

Reducing the number of sutures for vesicourethral anastomosis in radical retropubic prostatectomy  

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Full Text Available OBJECTIVE: To prospectively evaluate the outcome of using a two-suture technique for the vesicourethral anastomosis (VUA during radical retropubic prostatectomy (RRP. MATERIAL AND METHODS: Two groups of 50 patients each underwent nerve-sparing RRP for localized prostate cancer by one surgeon. In one group, the vesicourethral anastomosis was performed using 2 Vicryl 2-0 stitches placed at the 3- and 9-o’clock positions and in the other group 6 Vicryl 2-0 stitches were placed at the 2-, 4-, 6-, 8-, 10- and 12-o’clock positions. The intraoperative and perioperative parameters analyzed were time to perform the VUA, time to remove the drain and hospitalization. The rate of incontinence, anastomotic stricture and erectile function were included in the outcome analysis. RESULTS: The anastomotic time differed statistically between the 2 groups (mean 3.3 minutes for the 2-suture group and 10.5 minutes for the 6-suture group, p < 0.0001 with similar periods of drain removal (mean 3.12 days for the 2-suture group and 3.45 days for the 6-suture group; p = 0.13 and hospitalization (mean 4.66 days for the 2-suture group and 5.3 days for the 6-suture group; p = 0.09. The functional outcome was excellent for the 2-suture group with no patient suffering from incontinence or anastomotic strictures 1 year postoperatively, while in the 6-suture group there were 2 patients (4% suffering from incontinence (2 underwent sling procedure and 1 patient suffered from anastomotic stricture. CONCLUSION: The low number of sutures in the 2-suture VUA technique reduces operating times, does not influence perioperative and intraoperative parameters and results in excellent functional outcome.

Evangelos M. Mazaris

2009-04-01

346

Rheometric research of polypropylene Licocene PP2602 melts  

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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

347

Acute skier's thumb repaired with a proximal phalanx suture anchor.  

Science.gov (United States)

The purpose of this study was to determine the functional outcome of a surgical technique for the repair of injuries of the ulnar collateral ligament of the thumb. A 14-point questionnaire was developed to determine functional outcome after surgical repair of acute ulnar collateral ligament rupture. Early ulnar collateral ligament repair was performed on 58 patients with grade III sprains (complete rupture) of the ligament using a new technique that employs a suture anchor for fixation. Forty-five patients were interviewed at a minimum postoperative interval of 12 months and were included in this study. Forty-four patients (98%) believed they had a stable repair, were satisfied with their surgery, and would have it again if necessary. Forty-four patients (98%) were not hindered in their day-to-day activities and had a functional range of motion. Mild discomfort was felt by eight of our patients (17%), but only three patients (7%) had pain with activities. The average time to return to skiing was 1.7 days. The use of a suture anchor provided a strong and stable repair if the surgery was performed early. PMID:9784810

Zeman, C; Hunter, R E; Freeman, J R; Purnell, M L; Mastrangelo, J

1998-01-01

348

Stapler suture of the pharynx after total laryngectomy.  

Science.gov (United States)

The use of a stapler for pharyngeal closure during total laryngectomy was first described in 1971. It provides rapid watertight closure without surgical field contamination. The objective of our study was to compare the incidence of pharyngocutaneous fistula after total laryngectomy with manual and mechanical closures of the pharynx. This was a non-randomised, prospective clinical study conducted at two tertiary medical centres from 1996 to 2011 including consecutive patients with laryngeal tumours who underwent total laryngectomy. We compared the incidence of pharyngocutaneous fistula between two groups of patients: in 20 patients, 75 mm linear stapler closure was applied, whereas in 67 patients a manual suture was used. Clinical data were compared between groups. The groups were statistically similar in terms of gender, age, diabetes mellitus, smoking and alcohol consumption and tumour site. The group of patients who underwent stapler-assisted pharyngeal closure had a higher number of patients with previous tracheotomy (p < 0.001) and previous chemoradiation (p < 0.001). The incidence of pharyngocutaneous fistula was 30% in the mechanical closure group and 20.9% in the manual suture group (p = 0.42). In conclusion the use of the stapler does not increase the rate of fistulae. PMID:24843218

Dedivitis, R A; Aires, F T; Pfuetzenreiter, E G; Castro, M A F; Guimarães, A V

2014-04-01

349

Assessing suturing techniques using a virtual reality surgical simulator.  

Science.gov (United States)

Advantages of virtual-reality simulators surgical skill assessment and training include more training time, no risk to patient, repeatable difficulty level, reliable feedback, without the resource demands, and ethical issues of animal-based training. We tested this for a key subtask and showed a strong link between skill in the simulator and in reality. Suturing performance was assessed for four groups of participants, including experienced surgeons and naive subjects, on a custom-made virtual-reality simulator. Each subject tried the experiment 30 times using five different types of needles to perform a standardized suture placement task. Traditional metrics of performance as well as new metrics enabled by our system were proposed, and the data indicate difference between trained and untrained performance. In all traditional parameters such as time, number of attempts, and motion quantity, the medical surgeons outperformed the other three groups, though differences were not significant. However, motion smoothness, penetration and exit angles, tear size areas, and orientation change were statistically significant in the trained group when compared with untrained group. This suggests that these parameters can be used in virtual microsurgery training. PMID:20201052

Kazemi, Hamed; Rappel, James K; Poston, Timothy; Hai Lim, Beng; Burdet, Etienne; Leong Teo, Chee

2010-09-01

350

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

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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

351

Comparison of effects of suture and cyanoacrylate tissue adhesive on bacterial counts in contaminated lacerations.  

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We studied the effects of closing lacerations with suture or cyanoacrylate tissue adhesive on staphylococcal counts in inoculated guinea pig lacerations. Wounds closed with adhesive alone had lower counts than wounds containing suture material (P < 0.05). The results of a time-kill study were consistent with a bacteriostatic adhesive effect of the adhesive against Staphylococcus aureus.

Howell, J. M.; Bresnahan, K. A.; Stair, T. O.; Dhindsa, H. S.; Edwards, B. A.

1995-01-01

352

Tibial tubercle osteotomy for access during revision knee arthroplasty: Ethibond suture repair technique  

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Abstract Background Tibial Tubercle Osteotomy has shown much promise in revision total knee replacement. Methods of repair previously described include screw and wire fixation. Both methods have significant complications. Methods This article describes suture fixation of the osteotomy using Ethibond sutures placed medially with a lateral periosteal hinge. Results This method of fixation relies upon an adequate osteotomy segment including the entire...

Deane Crawford R; Ferran Nicholas A; Ghandour Adel; Morgan-Jones Rhidian L

2008-01-01

353

In vivo analysis of bone strain about the sagittal suture in macaca mulatta during masticatory movements.  

Science.gov (United States)

In vivo strain gauge analysis demonstrated that tensile bone strain is transmitted along the cranial vault to the parasagittal region during isotonic temporalis contraction. This strain is sufficient to cause measurable separation of the sagittal suture, and thus could influence growth at the sutural margins. PMID:102671

Behrents, R G; Carlson, D S; Abdelnour, T

1978-01-01

354

Colonic anastomosis using the biofragmentable anastomotic ring and manual suture: a prospective, randomized study.  

Science.gov (United States)

One hundred and fifty consecutive patients undergoing colonic surgery were randomized into two groups: 71 underwent hand-suture with a two-layer anastomosis of resorbable suture material (3/0 Dexon) and 79 were fitted with the biofragmentable anastomotic ring (Valtrac-BAR). Five patients, two treated using the BAR and three by suturing, developed anastomotic leakage which required a Hartmann-type reoperation. This was successful in four; one patient in the suture group died after reoperation. One patient who underwent suture had an early anastomotic stricture with fatal sequelae. Three other patients (one in the BAR group and two in the suture group) died after operation from other causes. Thus the mortality rate was 6 per cent in the suture group and 1 per cent in the BAR group. During follow-up, one patient in each group underwent reoperation for anastomotic stricture. Recovery of the gastrointestinal tract was similar in the two groups regarding duration of nasogastric drainage, intravenous fluid therapy and ileus. There was no difference between the groups in duration of hospital stay. The BAR seems to be a safe and reliable alternative to conventional suture anastomosis in colonic surgery. PMID:1611459

Gullichsen, R; Havia, T; Ovaska, J; Rantala, A

1992-06-01

355

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

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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

356

Blood flow through sutured and coupled microvascular anastomoses: A comparative computational study.  

Science.gov (United States)

This study uses computational fluid dynamics (CFD) to model blood flow through idealised sutured and coupled arterial anastomoses to investigate the affect of each technique on intravascular blood flow. Local flow phenomena are examined in detail to study characteristics that potentially initiate thrombus formation; for example, changes in velocity profile, wall shear stress (WSS), and shear strain rate (SSR). Idealised geometries of sutured and coupled anastomoses were created with dimensions identical to microvascular suture material and a commercially available coupling device using CFD software. Vessels were modelled as non-compliant 1 mm diameter ducts, and blood was simulated as a Newtonian fluid, in keeping with previous studies. All analyses were steady-state and performed on arteries. The sutured simulation revealed a reduced boundary velocity profile; high WSS; and high SSR at the suture sites. The coupled anastomosis simulation showed a small increase in maximum WSS at the anastomotic region compared to a pristine vessel, however, this was less than half that of the sutured model. The coupled vessel displayed an average WSS equivalent to a pristine vessel simulation. Taken together these observations demonstrate a theoretically more thrombogenic profile in a sutured anastomosis when compared to a coupled vessel. Data from simulations on a coupled anastomosis reveal a profile that is nearly equivalent to that of a pristine vessel. Based purely on the combination of less favourable flow properties shown using these idealised arterial models, the sutured method is potentially more thrombogenic than a coupled anastomosis. PMID:24731801

Wain, Richard A J; Whitty, Justin P M; Dalal, Milind D; Holmes, Michael C; Ahmed, Waqar

2014-07-01

357

Prospective randomized controlled trial investigating the type of sutures used during hepatectomy  

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Full Text Available AIM: To determine whether absorbable sutures or non-absorbable sutures are better in preventing surgical site infection (SSI, in this paper we discuss the results of a randomized clinical trial which examined the type of sutures used during hepatectomy. METHODS: All hepatic resections performed from January 2007 to November 2008 at the Department of Surgery at Iizuka Hospital in Japan were included in this study. There were 125 patients randomly assigned to an absorbable sutures (Vicryl group or non-absorbable sutures (Silk group. RESULTS: SSI was observed in 13.6% (17/125 patients participating in this study, 11.3% in the Vicryl group and 15.8% in the Silk group. Incisional SSI including superficial and deep SSI, was observed in 8% of the Vicryl group and 9.5% of the Silk group. Organ/space SSI was observed in 3.2% of the Vicryl group and 6.0% of the Silk group. There were no significant differences, but among the patients with SSI, the period for recovery was significantly shorter for the Vicryl group compared to the Silk group. CONCLUSION: The incidence of SSI in patients receiving absorbable sutures and silk sutures is not significantly different in this randomized controlled study; however, the period for recovery in patients with SSI was significantly shorter for absorbable sutures.

Norifumi Harimoto

2011-01-01

358

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

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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

359

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 chemical structure of the PGA sutures

1983-01-01

360

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)

2009-01-01

 
 
 
 
361

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

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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

362

A comparison of intramuscular ketamine with high dose intramuscular midazolam with and without intranasal flumazenil in children before suturing  

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Objectives—(a) To compare the use of high dose intramuscular midazolam with and without intranasal flumazenil in children after suturing. (b) To compare the use of high dose intramuscular midazolam with low dose intramuscular ketamine in children before suturing.

2001-01-01

363

Comparative study between two techniques of incisional hernia repair with polypropylene mesh in rabbits Estudo comparativo entre duas técnicas de tratamento da hérnia incisional em coelhos utilizando a tela de polipropileno  

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Full Text Available PURPOSE: To compare two different incisional hernia repair techniques (repair with a polypropylene mesh reinforcement on the peritonium-aponeurosis versus polypropylene mesh sutured to the borders of the hernial ring as a bridge in rabbits. METHODS: Incisional hernia was experimentally developed through a 4-cm median incision in 60 rabbits. After 30 days, half of the animals were operated for primary wall closure and placement of a polypropylene mesh reinforcement, while the other half had a polypropylene mesh sutured to the borders of the hernial ring as a bridge. Clinical development, scar breaking strength, as well as gross, microscopic and morphometric parameters were evaluated in all animals 30, 60, and 90 days after repair. RESULTS: No significant differences in breaking strength or histological parameters were observed between groups at any time point studied. No statistical difference regarding complications was detected, although denser and firmer adhesions to the abdominal wall were seen after the mesh was placed as a " bridge" . CONCLUSIONS: No significant differences between the incisional hernia repair techniques assessed were observed regarding breaking strength, and histological and morphometric parameters. The number of complications was similar in both study groups. However, adhesion of abdominal cavity organs to the scar area was much denser after the placement of a mesh to bridge the defect.OBJETIVO: Comparar duas técnicas de tratamento da hérnia incisional em coelhos utilizando a tela de polipropileno apoiando um reforço peritônio - aponeurótico ou suturada nas bordas do anel herniário 'em ponte" . MÉTODOS: Foram operados 60 coelhos para a produção de hérnia incisional, em uma incisão mediana de 4 centímetros. Após 30 dias, metade dos animais foram operados com o fechamento primário da parede, com colocação de uma tela de polipropileno apoiando o reforço e a outra metade dos animais com a colocação da tela suturada nas bordas do anel herniário " em ponte" . Os animais foram avaliados com 30 (M1, 60 (M2e 90 (M3 dias de pós-operatório. Os parâmetros analisados foram a evolução clínica, análise da força de ruptura da cicatriz, estudo macroscópico, análise microscópica e morfométrica. RESULTADOS: Não foram observadas diferenças significantes com relação a força de ruptura e estudos histológicos nos dois grupos e vários momentos estudados. Não houve diferença estatística com relação às complicações, embora os animais que receberam a tela " em ponte" tiveram aderências mais firmes e intensas à parede abdominal. CONCLUSÕES: As duas técnicas utilizadas para correção da hérnia incisional em coelhos não mostraram diferenças significantes quanto a força de ruptura, análise histológica e morfométrica. O número de complicações foi semelhante, porém a aderência de órgãos da cavidade abdominal à área de cicatriz foi muito mais intensa no grupo em que a tela foi colocada " em ponte" .

José Guilherme Minossi

2010-10-01

364

Effect of disagreement between refractive, keratometric, and topographic determination of astigmatic axis on suture removal after penetrating keratoplasty  

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BACKGROUND/AIMS—Post-keratoplasty astigmatism can be managed by selective suture removal in the steep axis. Corneal topography, keratometry, and refraction are used to determine the steep axis for suture removal. However, often there is a disagreement between the topographically determined steep axis and sutures to be removed and that determined by keratometry and refraction. The purpose of this study was to evaluate any difference in the effect of suture removal, on visual acuity and astig...

Sarhan, A.; Dua, H.; Beach, M.

2000-01-01

365

End-on extramucosal single layer suture with double anchoring in the submucosa on rabbits  

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Full Text Available The techniques of gastrointestinal surgical sutures have been frequently focused in controversial publications. These ones concern not only anastomosis? types but also about thread types and how to apply them. The values of the submucosa as layer of greatest resistence of the digestive tube was already known since the past century. The aim of this study is to avaluate the suture in an extramucosal single-layer suture with double anchoring of the submucosa, a technical detail not found in the searched literature. This experiment was carried out using 36 white,male adults New Zealand, rabbits divided into three groups which differed only regarding day of re-operation and euthanasia, as followed: group I ( 4 days, group II (7 days and group III ( 15 days. Two transversal and parallel gastrotomies were perfomed in the same animal, one distal and other proximal, of with 4 cm extension each. In these gastrotomies two types of sutures were alternated : 1- End-on extramucosal single-layer suture and 2- End-on extramucosal single-layer suture, with double anchoring in the submucosa. Macroscopic and microscopic studies were perfomed on the suture line in both gastrotomies and in each period of euthanasia. Except for the serosa item whose results were similar for both sutures, statiscally, the extramucosal single-layer suture, with double anchoring of submucosa layer showed better macro and microscopic results than the extramucosal single-layer suture in group I (4 days. In the others periods of euthanasia (groups II and III, the statistical results were similar.

Nascimento Luiz Roberto do

1999-01-01

366

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

367

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.

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

368

Effects of irradiated polypropylene compatibilizer on the properties of short carbon fiber reinforced polypropylene composites  

Science.gov (United States)

In this study, the effects of irradiated polypropylene (PP) compatibilizer addition into PP matrix on the interfacial adhesion between the carbon fiber (CF) and PP matrix were investigated. Unirradiated and irradiated PPs were blended, and two types of carbon fibers; unsized (surface treated) and sized, were used for composites preparation. In order to characterize the physical and morphological properties of all CF reinforced composites prepared, tensile tests, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and Positron annihilation lifetime spectroscopy (PALS) were performed. The strong compatibilizing effects of irradiated PP on the mechanical properties of composites were noticed. It has been found that breaking strength values were increased up to 30%. The compatibilizing effect of irradiated PP was also confirmed with SEM micrographs and PALS. It has been seen that blending PP matrix with irradiated PP improved the interfacial adhesion between the carbon fiber and matrix materials. The melting point temperatures of composites were not changed significantly for all composites. The results showed that irradiated PP as a compatibilizer together with unsized carbon fiber in place of sized carbon fiber can be used in order to improve the mechanical properties of carbon fiber reinforced PP composites.

Gamze Karsli, Nevin; Aytac, Ayse; Akbulut, Meshude; Deniz, Veli; Güven, Olgun

2013-03-01

369

New functionalized polypropylenes as controlled architecture compatibilizers for polypropylene layered silicates nanocomposites.  

Science.gov (United States)

Polypropylene (PP) samples functionalized with Maleic Anhydride (MAH) were used as interfacial coupling agents during the preparation of PP based layered silicate nanocomposites (PP-LSN). To prepare these functionalized PP samples, butyl 3-(2-furyl)propenoate (BFA) was used as coagent during the radical post-functionalization with MAH to avoid the polymer degradation. The obtained materials, differing from the functionalization degree (FD) and structure (MW and molecular weight distribution), were accurately characterized and firstly employed as polymer matrices for PP-LSN preparation to study the influence of their architecture on clay dispersion and thus on their intercalation capability. Successively, PP-LSNs were prepared by using PP as matrix and 5 phr of the above compatibilizers. Morphological, thermal, mechanical and thermo-mechanical analyses of the nanocomposites pointed out that the higher molecular weight PP-g-MAH samples allow to achieve simultaneously a good intercalation within the filler and a significant compatibilization with pristine PP chains, leading to high performances PP-LSNs. PMID:19928162

Augier, Sylvain; Coiai, Serena; Pratelli, Daniele; Conzatti, Lucia; Passaglia, Elisa

2009-08-01

370

Polypropylene/calcium carbonate nanocomposites – effects of processing techniques and maleated polypropylene compatibiliser  

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Full Text Available The mechanical properties and crystalline characteristics of polypropylene (PP and nano precipitated calcium carbonate (NPCC nanocomposites prepared via melt mixing in an internal mixer and melt extrusion in a twin screw extruder, were compared. The effect of maleic anhydride grafted PP (PP-g-MAH as a compatibiliser was also studied using the internal mixer. At low filler concentration of 5 wt%, impact strength was better for the nanocomposites produced using the internal mixer. At higher filler loading of more than 10 wt%, the extrusion technique was more effective to disperse the nanofillers resulting in better impact properties. The impact results are consistent with the observations made from Scanning Electron Microscope (SEM morphology study. As expected, the flexural modulus of the nanocomposites increased with filler concentration regardless of the techniques utilised. At a same filler loading, there was also no significant difference in the moduli for the two techniques. The tensile strength of the mixed nanocomposites were found to be inferior to the extruded nanocomposites. Introduction of PP-g-MAH improved the impact strength, tensile strength and modulus of the mixed nanocomposites. The improvements may be attributed to better interfacial adhesion, as evident from the SEM micrographs which displayed better dispersion of the NPCC in the presence of the compatibiliser. Though NPCC particles have weak nucleating effect on the crystallization of the PP, addition of PP-g-MAH into the mixed nanocomposites has induced significant crystallization of the PP.

2010-10-01

371

Subdermal placement of sutures in double eyelid surgery.  

Science.gov (United States)

Increasing numbers of Asian patients of varying ethnicity are expressing preferences and expectations for a specific aesthetic appearance following double eyelid surgery. Those of Northern Mongolian ethnicity (Northern Chinese, Japanese, or Korean heritage) generally prefer a narrow crease, whereas those of Southern Mongolian ethnicity (Indonesian, Filipino, or Malaysian) prefer a wider fold. Older techniques performed until the mid-1990s resulted in a deep fold, giving the patients a more "Western" appearance. In this article, the author describes a modified technique of placing the suture in the subdermal layer, which allows for variety in the width of the fold, enabling the surgeon to retain anatomical aspects that are typical of each patient's ethnicity. With this technique, an Asian patient may now choose the width of fold that he or she prefers, resulting in a more ethnically natural look. PMID:23718979

Zubiri, Jesusito S

2013-07-01

372

Single-incision laparoscopic splenectomy with innovative gastric traction suture.  

Science.gov (United States)

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. PMID:21197246

Srikanth, G; Wasim, M D; Sajjad, A; Shetty, Neel

2011-01-01

373

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)

2000-01-01

374

Study of blends based on polypropylene and Epdm elastomer  

International Nuclear Information System (INIS)

Polymer blends based on EPDM elastomer and isostatic polypropylene (P P) were prepared in a Bra bender plastograph, coupled with a Brabender mixer chamber, in different composition ranges and processing conditions. It was evaluated the mechanical and flow properties of EPDM/P P blends, and also the effect of the addition of controlled degraded polypropylene (P P-deg) on the properties of these mixtures. The characterization and the study of the compatibilization degree of EPDM/P P and EPDM/P P/P P-deg blends were analyzed by differential scanning calorimetry (DSC), thermal dynamic mechanical analysis (DTMA), thermal gravimetric analysis (TGA), 13 C-nuclear magnetic resonance (13C-NMR) and scanning electron microscopy (SEM). (author)

1995-01-01

375

Development of a sensor for polypropylene degradation products.  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the development of a sensor to detect the oxidative and radiation induced degradation of polypropylene. Recently we have examined the use of crosslinked assemblies of nanoparticles as a chemiresistor-type sensor for the degradation products. We have developed a simple method that uses a siloxane matrix to fabricate a chemiresistor-type sensor that minimizes the swelling transduction mechanism while optimizing the change in dielectric response. These sensors were exposed with the use of a gas chromatography system to three previously identified polypropylene degradation products including 4-methyl-2-pentanone, acetone, and 2-pentanone. The limits of detection 210 ppb for 4-methy-2-pentanone, 575 ppb for 2-pentanone, and the LoD was unable to be determined for acetone due to incomplete separation from the carbon disulfide carrier.

Sawyer, Patricia Sue; Howell, Stephen Wayne; Hochrein, James Michael; Dirk, Shawn M.; Bernstein, Robert; Washburn, Cody M.; Graf, Darin C.

2009-04-01

376

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

2006-01-01

377

Analysis of the fracture behavior of polypropylene: sawdust composites  

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Full Text Available Natural fiber reinforced composite is an emerging area in Polymer science. The use of lignocellulosic materials in thermoplastic composites may contribute to reduce the waste of vegetal biomass. The natural fibers are biodegradable, low cost materials having density and specific properties comparable to those of conventional fiber composites. In this work composites of polypropylene (PP plus maleated polypropylene (MAPP filled with sawdust were prepared under fixed processing conditions (mixing temperature, mixing time and rate of rotation. The composites were fractured by tension and the fracture mechanisms were characterized by scanning electron microscopy. The SEM studies of the fractured surfaces of the composites indicate that the failure is due to fiber pull-out accompanied by tearing of the matrix; the pull-out increases with MAPP content.

João C. Miguez Suarez

2005-06-01

378

Analysis of the fracture behavior of polypropylene: sawdust composites  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Natural fiber reinforced composite is an emerging area in Polymer science. The use of lignocellulosic materials in thermoplastic composites may contribute to reduce the waste of vegetal biomass. The natural fibers are biodegradable, low cost materials having density and specific properties comparabl [...] e to those of conventional fiber composites. In this work composites of polypropylene (PP) plus maleated polypropylene (MAPP) filled with sawdust were prepared under fixed processing conditions (mixing temperature, mixing time and rate of rotation). The composites were fractured by tension and the fracture mechanisms were characterized by scanning electron microscopy. The SEM studies of the fractured surfaces of the composites indicate that the failure is due to fiber pull-out accompanied by tearing of the matrix; the pull-out increases with MAPP content.

João C. Miguez, Suarez; Fernanda M. B., Coutinho; Thais H., Sydenstricker.

379

Weatherability of polypropylene monofilaments. Effects of fiber production conditions  

International Nuclear Information System (INIS)

From a comparison of the photo-and ?-irradiation-initiated oxidations of monofilaments and films, polypropylene oxidation rates and product ratios were found to be independent of sample morphology and orientation. Filament sensitivity to photo-oxidation was, however, drastically affected by extrusion and draw conditions, photosensitivity increasing with increasing draw speed and decreasing draw temperature. Draw effects were minimized by the exclusion of oxygen, indicating that free radicals produced by backbone cleavage during draw react with oxygen to give chromophoric oxidation products. The most important product detectable after drawing was probably the polypropylene hydroperoxide. A phenolic antioxidant reduced hydroperoxide formation, although sufficient hydroperoxide was still produced to accelerate photodegradation as compared with a similarly stabilized undrawn filament. Melt oxidation within the extruder was concluded to be much more important than thermal oxidation of the extruded filament as it cooled on the spinline

1977-01-01

380

Surface characterization of plasma-treated polypropylene fibers  

International Nuclear Information System (INIS)

Plasma treatment is increasingly being used for surface modification of different materials in many industries. In this study, different techniques were employed to characterize the surface properties of plasma treated polypropylene fibers. The chemical nature of the fiber sufaces has been investigated by X-ray photoelectron spectroscopy (XPS). The XPS examination indicated the presence of oxygen-containing functional groups on fiber surfaces after plasma treatment. The Atomic Force Microscopy (AFM) scans revealed the evolution of surface morphology under different experimental conditions. A Philips Environmental Scanning Electron Microscopy (ESEM) was also used to study the wetting behavior of the fibers. In the ESEM, relative humidity can be raised to 100% to facilitate the water condensation onto fiber surfaces for wetting observation. The ESEM observation revealed that the plasma treatment significantly altered the surface wettability of polypropylene fibers

2004-06-01

 
 
 
 
381

Mechanical properties of rubberwood fibers polypropylene epoxidized natural rubber composites  

International Nuclear Information System (INIS)

Research on rubberwood fibers-thermoplastic composites have been carried out by several workers in the past several years. The main focus was to enhance the properties of the resultant composites in view of the incompatibility of the two components. Thus, efforts have been made to enhance their properties by using coupling agents, treating the fibers and modifying the matrices. In this study, the rubberwood polypropylene composite was used as a base material and the addition of epoxidized natural rubber (ENR) is to provide a damping property of the composite with the final aim to produce a sound and noise proofing products. Initially, the processing and compositions of rubberwood fibers and polypropylene was optimized at the 50:50 w/w ratio using melt blend internal mixer. The processing parameters were established. Subsequently, the mechanical properties of the composites were determined with addition of 1-4% of ENR. (Author)

2004-07-12

382

POLYPROPYLENE/STARCH BLENDS: STUDY OF THERMAL AND MORPHOLOGICAL PROPERTIES  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english 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.

383

Effects of environmental ageing on HMS-polypropylene/Cloisite nanocomposites  

Science.gov (United States)

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.; Oliani, W. L.; Ferreto, H. F. R.; Lugao, A. B.; Parra, D. F.

2014-05-01

384

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

2006-09-23

385

Radical structure and its role in the oxidative degradation of ?-irradiated polypropylene  

International Nuclear Information System (INIS)

The kinetics of radical species formed in ?-irradiated polypropylene can be followed by observing time dependent changes in ESR spectra. Oxidative mechanisms in isotactic polypropylene have been related to the formation of radicals in the literature. This study examines the oxidation of polypropylene samples containing alkyl and allyl or polyenyl radicals when exposed to air. A parallel study of mechanical properties under similar conditions has been made and the comparative results between ESR and mechanical property measurements will be discussed herein. (author)

1978-10-26

386

Microstructure and Properties of Polypropylene/Carbon Nanotube Nanocomposites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the last few years, great attention has been paid to the preparation of polypropylene (PP) nanocomposites using carbon nanotubes (CNTs) due to the tremendous enhancement of the mechanical, thermal, electrical, optical and structural properties of the pristine material. This is due to the unique combination of structural, mechanical, electrical, and thermal transport properties of CNTs. However, it is well-known that the properties of polymer-based nanocomposites strongly depend on the disp...

Dimitrios Bikiaris

2010-01-01

387

Study of the properties of polypropylene-PHB blends  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

388

Fracture toughness of polypropylene-based particulate composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The fracture behaviour of polymers is strongly affected by the addition of rigid particles. Several features of the particles have a decisive influence on the values of the fracture toughness: shape and size, chemical nature, surface nature, concentration by volume, and orientation. Among those of thermoplastic matrix, polypropylene (PP) composites are the most industrially employed for many different application fields. Here, a review on the fracture behaviour of PP-based part...

Arenco?n Osuna, David; Velasco Perero, Jose? Ignacio

2009-01-01

389

Synthesis and properties of elastomeric poly(propylene)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Elastomeric poly(propylene) with low percentages of isotactic pentads and high molecular weight was synthesized using unbridged "oscillating" metallocenes. The polymer sample with the highest [mmmm] content (22%) shows a small amount of crystallinity, which is highly influenced by the thermal history, and differs significantly in stress-strain and dynamic mechanical properties from all other samples. Polymers with lower isotacticity index, although lacking crystallinity in thermal ana...

1999-01-01

390

Polyethylene and polypropylene nanocomposites based upon an oligomerically modified clay  

International Nuclear Information System (INIS)

Montmorillonite clay was modified with an oligomeric surfactant, which was then melt blended with polyethylene and polypropylene in a Brabender mixer. The morphology was characterized by X-ray diffraction and transmission electron microscopy, while thermal stability was evaluated from thermogravimetric analysis and the fire properties by cone calorimetry. The nanocomposites are best described as mixed immiscible/intercalated/delaminated systems and the reduction in peak heat release rate is about 40% at 5% inorganic clay loading

2005-06-01

391

Polyethylene and polypropylene nanocomposites based upon an oligomerically modified clay  

Energy Technology Data Exchange (ETDEWEB)

Montmorillonite clay was modified with an oligomeric surfactant, which was then melt blended with polyethylene and polypropylene in a Brabender mixer. The morphology was characterized by X-ray diffraction and transmission electron microscopy, while thermal stability was evaluated from thermogravimetric analysis and the fire properties by cone calorimetry. The nanocomposites are best described as mixed immiscible/intercalated/delaminated systems and the reduction in peak heat release rate is about 40% at 5% inorganic clay loading.

Zhang Jinguo [Department of Chemistry, Marquette University, PO Box 1881, Milwaukee, WI 53201 (United States); Jiang, David D. [Department of Chemistry, Marquette University, PO Box 1881, Milwaukee, WI 53201 (United States); Wilkie, Charles A. [Department of Chemistry, Marquette University, PO Box 1881, Milwaukee, WI 53201 (United States)]. E-mail: charles.wilkie@marquette.edu

2005-06-15

392

Bacterial Growth on Chitosan-Coated Polypropylene Textile  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Biofouling is a problem common in all systems where microorganisms and aqueous environment meet. Prevention of biofouling is therefore important in many industrial processes. The aim of this study was to develop a method to evaluate the ability of material coating to inhibit biofilm formation. Chitosan-coated polypropylene nonwoven textile was prepared using dielectric barrier discharge plasma activation. Resistance of the textile to biofouling was then tested. First, the textile was submerge...

Erben, D.; Hola, V.; Jaros, J.; Rahel, J.

2012-01-01

393

Fibre drawing from blends of polypropylene and liquid crystal polymers  

Energy Technology Data Exchange (ETDEWEB)

The paper highlights the hot-drawing of melt-extruded fibres consisting of a polypropylene (PP) matrix and liquid crystal polymer (LCP) as a minor component in a separate phase. During drawing, LCP fibrils, formed within the fibre blend during melt-extrusion, are liable to split into short fragments. After conventional one-stage drawing, fibre reinforcement ceases to be provided by the LCP, and indeed mechanical performance is generally reduced.

Qin, Y.; Brydon, D.L.; Mather, R.R. [Heriot-Watt Univ., Galashiels (United Kingdom)

1995-12-01

394

USING OF FIBER COMPOSITE OF POLYPROPYLENE TO MANUFACTURING CARS BUMPERS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This research aims to manufacturing cars bumpers from polypropylene resin reinforced by it glass fibers with different reinforcement percentage (10%,30%,50%,70%) and study the impact strength and compressive strength for obtained composite material .An Improvementwas happened in these properties after reinforcement by fibers The value of mechanical properties will increase with increasing percentage of reinforcement . Impact strength increased from (85Kj/m2) to (498Kj/m2) and compressive stre...

2012-01-01

395

Glass Fiber Reinforced Polypropylene Mechanical Properties Enhancement by Adhesion Improvement  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Glass fibers (GF) are the reinforcement agent most used in polypropylene (PP) based composites, as they have good balance between properties and costs. However, their final properties are mainly determined by the strength and stability of the polymer-fiber interphase. Fibers do not act as an effective reinforcing material when the adhesion is weak. Also, the adhesion between phases can be easily degraded in aggressive environmental conditions such as high temperatures and/or elevated moisture...

2012-01-01

396

Aqueous Processes for Dyeing Generic, Unmodified Polypropylene Fiber  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 signi...

2010-01-01

397

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)

2009-10-13

398

Creep failure of polypropylene: experiments and constitutive modeling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Observations are reported on isotactic polypropylene in uniaxial tensile tests with various strain rates, relaxation tests with various strains, and creep tests with various stresses at ambient temperature. Constitutive equations are derived for the viscoelastic-viscoplastic responses and damage of a semicrystalline polymer at three-dimensional deformations. Adjustable parameters in the stress-strain relations are found by fitting the experimental data. The model is applied to predict creep-f...

Drozdov, A. D.; Christiansen, J. Dec

2009-01-01

399

Thermal simulation for geometric optimization of metallized polypropylene film capacitors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, we use an analytic model to calculate the losses in the metallized polypropylene film capacitors. The model is validated experimentally for capacitors having the same capacitance but different geometry. For each group of capacitors a temperature distribution in the roll is assumed with the aim of optimizing its thermal performance. It appears that the heating of a long capacitor is higher than that of an equivalent flat capacitor subjected to the same electric stresses.

El-husseini, M.; Venet, Pascal; Rojat, Ge?rard; Joubert, Charles

2002-01-01

400

FLAMMABILITY OF POLYPROPYLENE BASED COMPOSITE MIXED WITH INORGANIC RETARDANTS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Flammability of polypropylene based composite mixed with zinc borate - antimony pentoxide has been investigated. Retardant layer added on external surface of composite material with (4mm) thick, and tested by thermal erosion test. Antimony pentoxide was added with (10%, 20% and 30%) quantities to zinc borate for enhance the action of this material to react flame. This new retardant was exposed to Oxyacetylene torch flame with (10mm and 15mm) exposure ...

2013-01-01

 
 
 
 
401

Upgrading of recycled polypropylene by preparing flame retarded layered composite  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

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

2012-01-01

402

On engineering of properties of wood-polypropylene composite  

Digital Repository Infrastructure Vision for European Research (DRIVER)

New materials based on wood have the advantage in the sense that their properties can be engineered so as to correspond to user demands. The properties which can be engineered are those relating both to their utilisation and machining, in particular - the tensile strength, elongation at break, modulus of elasticity and impact resistance. The research at the Faculty of Forestry and "Hipol" Chemical Industry related to the new type of wood-polypropylene composite. The ...

2006-01-01

403

On engineering of properties of wood-polypropylene composite  

Digital Repository Infrastructure Vision for European Research (DRIVER)

New materials based on wood have the advantage in the sense that their properties can be engineered so as to correspond to user demands. The properties which can be engineered are those relating both to their utilisation and machining, in particular - the tensile strength, elongation at break, modulus of elasticity and impact resistance. The research at the Faculty of Forestry and "Hipol" Chemical Industry related to the new type of wood-polypropylene composite. The content of wood fi...

2006-01-01

404

Rheological and electrical analysis in carbon nanofibre reinforced polypropylene composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Two different types of carbon nanofibers (CNF) were incorporated in the same polypropylene (PP) matrix by twin-screw extrusion. The electrical characterization of both CNFs / PP composites as a function of volume fraction show different electrical performance: conducting and non-conducting. The objective of this work is to study the rheological behaviour of both composites with the aim of relating it to the electrical behaviour. The results indicate that the rheological behavio...

Lanceros-me?ndez, S.; Paleo, A. J.; Silva, J.; Hattum, F. W. J.; Ares, A. I.

2013-01-01

405

Mechanical properties of polypropylene/calcium carbonate nanocomposites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this work was to study the influence of calcium carbonate nanoparticles in both tensile and impact mechanical properties of a polypropylene homopolymer. Four compositions of PP/CaCO3 nanocomposites were prepared in a co-rotational twin screw extruder machine with calcium carbonate content of 3, 5, 7 and 10 wt. (%) The tests included SEM analyzes together with EDS analyzer and FTIR spectroscopy for calcium carbonate, tensile and impact tests for PP and the nanocomposites. The result...

Daniel Eiras; Luiz Antonio Pessan

2009-01-01

406

Microstructure of a cement matrix composite reinforced with polypropylene fibers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The present investigation deals with the microstructural characterization of a composite material, which is comprised of polypropylene fibers in an cement matrix, by means of environmental scanning electron microscopy (ESEM) and field emission scanning electron microscopy (FESEM). The microstructure of the different phases that compose the matrix is very heterogeneous, though there is a uniform distribution of the fibers inside it. The surface of this composite is different after setting, cur...

Rinco?n, J. M.; Romero, M.; Herna?ndez-crespo, M.; Talero, R.; Garci?a Santos, A.

2004-01-01

407

Microstructure and mechanical properties of Polypropylene/Polycarbonate blends  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: Researches, which are presented in this paper, consider the effect of chosen different weight ratios polycarbonate blended in a polypropylene matrix (PP/PC) at variable injection moulding conditions and its effect on the microstructure, and also on fracture and flexural properties.Design/methodology/approach: Composites contain between 0 and 30 wt % of polycarbonate and changes at constant rate of 10wt%. Specimens were produced with advantage of melt manipulation technology, further ...

2008-01-01

408

Foaming Behaviour, Structure, and Properties of Polypropylene Nanocomposites Foams  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work presents the preparation and characterization of compression-moulded montmorillonite and carbon nanofibre-polypropylene foams. The influence of these nanofillers on the foaming behaviour was analyzed in terms of the foaming parameters and final cellular structure and morphology of the foams. Both nanofillers induced the formation of a more isometric-like cellular structure in the foams, mainly observed for the MMT-filled nanocomposite foams. Alongside their crystalline characteristi...

Antunes, M.; Realinho, V.; Velasco, J. I.

2010-01-01

409

Foaming behaviour, structure, and properties of polypropylene nanocomposite foams  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work presents the preparation and characterization of compression-moulded montmorillonite and carbon nanofibre-polypropylene foams. The influence of these nanofillers on the foaming behaviour was analyzed in terms of the foaming parameters and final cellular structure and morphology of the foams. Both nanofillers induced the formation of a more isometric-like cellular structure in the foams, mainly observed for the MMT-filled nanocomposite foams. Alongside their crystalline characteristi...

Sousa Pais Antunes, Marcelo; Redondo Realinho, Vera Cristina; Velasco Perero, Jose? Ignacio

2010-01-01

410

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

411

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 Pa