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Sample records for 10-0 polypropylene suture

  1. Suture loosening and γ sterilization of 10-0 nylon

    The tissue reaction to 10-0 nylon sutures sterilized with γ-rays was compared to the reaction caused by 10-0 nylon thread sterilized with ethylene oxide. In a vascularized cornea more tissue reaction was seen to 10-0 nylon thread sterilized with γ-rays than to sutures sterilized with ethylene oxide gas. (Auth.)

  2. A comparative study of outcome of the absorbable suture polydioxanone and nonabsorbable suture polypropylene in laparotomy wound closure

    Kiran Shankar H.

    2016-06-01

    Full Text Available Background: Abdominal wound closure is one of the common operations for a general surgeon. Prevention of complications is important to reduce post-operative morbidity and mortality. Post-operative wound pain, wound infection, wound dehiscence, suture sinus formation; palpable knots and incisional hernia are the parameters are to be studied. Therefore, the present study was undertaken to compare polydioxanone and polypropylene suture material for abdominal fascial closure regarding morbidity in terms of post-operative wound complications. Methods: Patients admitted in the department of surgery, who undergo laparotomy operations, with midline abdominal incisions were included in the study. The recruited subjects were divided into Group-A, whom abdominal incisions are closed with non-absorbable suture material polypropylene and Group-B whom abdominal incisions are closed with absorbable suture material polydioxanone. Data was expressed as percentages. Results: The incidence of wound pain was observed in all the patients in both immediate and delayed post-operative period in the polypropylene suture material compared to polydioxanone. The incidence of wound infection was higher in polypropylene (24% compared to PDS (2%. There were 4% cases of wound dehiscence in the present study. The incidence of suture sinus formation was higher in the polypropylene suture material (9% compared to the polydioxanone suture material (2% in the delayed postoperative period. The incidence of palpable knots was higher in the polypropylene suture material (23% compared to the polydioxanone suture material. No cases of incisional hernia were reported with polydioxanone suture material. Conclusions: The overall morbidity from abdominal closure was considerably reduced in the Polydioxanone group. We encountered reduction in wound complications like burst abdomen, wound infection, wound pain, suture sinus formation, palpable knots and incisional hernia. Therefore

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

    Davis, N F

    2012-11-01

    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.

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

    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)

  5. Polypropylene

    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.

  6. Surgical treatment of traumatic eventration with polyester button and polypropylene mesh to strengthen the suture technique in equine

    Orlandini, Carla Faria; Steiner, Denis; Boscarato, André Giarola; Gimenes, Gabriel Coelho; Alberton, Luiz Romulo

    2016-01-01

    Background Defects in the abdominal wall of horses have high relapse rate. This is mainly in lateral eventrations and hernias caused by trauma from kicks of other horses or installation structures. The eventration region normally becomes swollen and there may be complications due to intestinal loop incarceration. The surgical treatment, consisting of reconstruction of the abdominal wall, frequently require biological or synthetic materials for the reinforcement of the suture line and tension ...

  7. 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

    Nelson Leonardo Kerdahi Leite de Campos

    2003-10-01

    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

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

    Álvaro Gianlupi

    2004-04-01

    Full Text Available OBJETIVO: Comparar a fixação da tela de prolipropileno na correção de defeitos músculo-aponeuróticos da parede abdominal com fio absorvível (poliglactina 910 e fio inabsorvível (polipropileno. MÉTODOS: Oitenta e um ratos machos da linhagem Wistar foram submetidos a ressecção longitudinal de um segmento músculo-aponeurótico e peritoneal (3x2 cm da parede abdominal, seguida por reforço com tela de polipropileno, em forma de ponte sobre a aponeurose. Foram distribuídos em dois grupos de acordo com o fio usado para fixação da tela: grupo poliglactina 910 - fixada com 8 pontos separados e eqüidistantes em forma de "U" com fio 4-0; e grupo polipropileno - fixada com fio 4-0. A pele foi suturada com fio de nylon 4-0. Após 90 dias, os animais foram submetidos à eutanásia e avaliados macroscopicamente, quanto à presença de hérnia e avaliação histológica da reação inflamatória crônica, absorção do fio e percentagem de fibrose pela técnica vídeo-morfométrica assistida por computador. Utilizaram-se as técnicas de coloração de hematoxilina-eosina e picrossírius. RESULTADOS: Não houve diferença estatisticamente significante entre os grupos, quanto à presença de hérnia incisional (p=0,194. Houve maior fibrose no grupo polipropileno pela avaliação histológica de reação inflamatória crônica, o que não foi verificado quando avaliado pela técnica vídeo-morfométrica (p=0,0005. Não houve diferença entre os grupos quando avaliados os gigantócitos, linfócitos e neutrófilos. Houve maior número de macrófagos no grupo polipropileno (p=0,02. Não houve absorção do fio poliglactina 910 após 90 dias. CONCLUSÃO: A fixação de tela de polipropileno pode ser feita com êxito com fios absorvíveis como a poliglactina 910.PURPOSE: The aim of this study is to assess fixation of a polypropylene mesh in the repair of incisional hernias comparing an absorbable (polyglactin 910 suture and an inabsorbable

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

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

    2008-01-01

    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

  10. GENIE Production Release 2.10.0

    Alam, M.; Andreopoulos, C.; M. Athar; Bodek, A.; Christy, E.; Coopersmith, B.; S. Dennis; Dytman, S.; Gallagher, H.; Geary, N; Golan, T.; Hatcher, R.; Hoshina, K.; Liu, J; Mahn, K.

    2015-01-01

    GENIE is a neutrino Monte Carlo event generator that simulates the primary interaction of a neutrino with a nuclear target, along with the subsequent propagation of the reaction products through the nuclear medium. It additionally contains libraries for fully-featured detector geometries and for managing various types of neutrino flux. This note details recent updates to GENIE, in particular changes introduced into the newest production release, version 2.10.0.

  11. GENIE Production Release 2.10.0

    Alam, M. [Aligarh Muslim Univ., Aligarh (India). Dept. of Physics; Andreopoulos, C. [Univ. of Liverpool (United Kingdom). Dept. of Physics; Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Rutherford Appleton Lab. (RAL); Athar, M. [Aligarh Muslim Univ., Aligarh (India). Dept. of Physics; Bodek, A. [Univ. of Rochester, NY (United States). Dept. of Physics; Christy, E. [Hampton Univ., Hampton, VA (United States). Dept. of Physics; Coopersmith, B. [Univ. of Rochester, NY (United States). Dept. of Physics; Dennis, S. [Univ. of Warwick, Coventry (United Kingdom). Dept .of Physics; Dytman, S. [Univ. of Pittsburgh, PA (United States). Dept. of Physics and Astronomy; Gallagher, H. [Tufts Univ., Medford, MA (United States). Dept. of Physics and Astronomy; Geary, N. [Univ. of Pittsburgh, PA (United States). Dept. of Physics and Astronomy; Golan, T. [Univ. of Rochester, NY (United States). Dept. of Physics; Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Hatcher, R. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Hoshina, K. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Physics. Wisconsin IceCube Particle Astrophysics Center; Liu, J. [College of William and Mary, Williamsburg, VA (United States). Dept. of Physics; Mahn, K. [Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy; Marshall, C. [Univ. of Rochester, NY (United States). Dept. of Physics; Morrison, J. [Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy; Nirkko, M. [Univ. of Bern (Switzerland). Albert Einstein Center for Fundamental Physics. Lab. for High Energy Physics (LHEP); Nowak, J. [Lancaster Univ. (United Kingdom). Dept. of Physics; Perdue, G. N. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Yarba, J. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-12-25

    GENIE is a neutrino Monte Carlo event generator that simulates the primary interaction of a neutrino with a nuclear target, along with the subsequent propagation of the reaction products through the nuclear medium. It additionally contains libraries for fully-featured detector geometries and for managing various types of neutrino flux. This note details recent updates to GENIE, in particular, changes introduced into the newest production release, version 2.10.0.

  12. Hypersensitivity to Suture Anchors

    Masafumi Goto

    2013-01-01

    Full Text Available Hypersensitivity to suture anchor is extremely rare. Herein, we present a case in which hypersensitivity to suture anchor was strongly suspected. The right rotator cuff of a 50-year-old woman was repaired with a metal suture anchor. Three weeks after the surgery, she developed erythema around her face, trunk, and hands, accompanied by itching. Infection was unlikely because no abnormalities were detected by blood testing or by medical examination. Suspicious of a metallic allergy, a dermatologist performed a patch testing 6 months after the first surgery. The patient had negative reactions to tests for titanium, aluminum, and vanadium, which were the principal components of the suture anchor. The anchor was removed 7 months after the first surgery, and the erythema disappeared immediately. When allergic symptoms occur and persist after the use of a metal anchor, removal should be considered as a treatment option even if the patch test result is negative.

  13. Glaucoma laser suture lysis.

    Macken, P; Buys, Y; Trope, G E

    1996-01-01

    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...

  14. EFFECTS OF DIFFERENT SUTURE MATERIALS ON TISSUE HEALING

    Fırat SELVİ

    2016-01-01

    Full Text Available Purpose: The purpose of this study was to investigate the healing differences in between four different widely used suture materials in the oral surgery practice, including silk (Perma- Hand; Ethicon, INC., Somerville, NJ, USA, polypropylene (Prolene; Ethicon, INC., Somerville, NJ, USA, coated polyglactin 910 (Ethicon, INC., Somerville, NJ, USA. and polyglecaprone 25 (Ethicon, INC., Somerville, NJ, USA . Materials and Methods: 20 male rats were randomly allocated into two groups depending on their sacrification days (post-operative 1st and the 7th days. Four longitudinal incision wounds, each 1cm in size, were created on the dorsum of each animal which were then primarily closed with four different types of sutures. Results: The effects of these suture materials on soft tissue healing were compared histopathologically, by means of density of the cells, necrosis, fibrosis, foreign body reaction, the presence of cells of acute and chronic infection. No statistically significant difference was observed between the groups regarding the density of the cells, necrosis, fibrosis, foreign body reaction, and the presence of the cells of acute & chronic infections. Of note, propylene showed slightly less tissue reaction among the other materials. Conclusion: The results of our study showed that there is no only one ideal suture material for surgical practice. The factors related to the patient, the type of the surgery and the quality of the tissue are important to decide an appropriate suture material.

  15. 7. Perineal suturing.

    Blease, Megan; Taylor, Kerry

    2016-04-01

    Preceptorship is the 15th series of 'Midwifery basics' targeted at practising midwives. The aim of these articles is to provide information to raise awareness of the impact of the work of midwives on women's experience, and encourage midwives to seek further information through a series of activities relating to the topic. During the transition from student midwife, the newly qualified practitioner (NQM) is required to obtain experience of perineal suturing. With exposure varying from student to student and inconsistency in teaching methods between hospital trusts, the NQM can be left feeling apprehensive and unsupported to learn this skill. Suturing is a major and sometimes traumatic event for childbearing women, whose experience can vary greatly, depending upon many factors, including environment, skill of those suturing, effective analgesia and waiting times. In this penultimate article of the series, Megan Blease and Kerry Taylor address the current issues and provide learning hints and tips for NQMs learning and practising the skill. PMID:27172679

  16. Comparative study of trabeculectomy using single sutures versus releasable sutures

    Matlach J

    2012-07-01

    Full Text Available Juliane Matlach, Niels Hoffmann, Florentina J Freiberg, Franz Grehn, Thomas KlinkDepartment of Ophthalmology, University of Wuerzburg, Wuerzburg, GermanyBackground: The purpose of this study was to compare the outcomes of trabeculectomy using single sutures or releasable sutures.Methods: This retrospective study analyzed the medical records of 61 patients who had undergone trabeculectomy using single sutures (n = 33, 54.1% or releasable sutures (n = 28, 45.9%. The scleral flap was secured with a mean 3.9 (range 3–5 single sutures in 33 patients and with three releasable sutures in 28 patients. Primary outcomes were the success rate, based on intraocular pressure and medication usage, and the frequency of complications and postsurgical interventions. The criteria used to determine complete success were, first, intraocular pressure <18 mmHg and, second, ≤21 mmHg and ≥20% intraocular pressure reduction without glaucoma medication.Results: All patients had an intraocular pressure ≤ 21 mmHg; 87.5% in the single suture group and 92.6% in the releasable suture group had an intraocular pressure < 18 mmHg at 24 months. There was a highly significant reduction in intraocular pressure to baseline values in both groups at the last visit. Applying the first criterion, complete success was achieved in 57.6% of patients with single sutures and 71.4% with releasable sutures, and based on the second criterion, 66.7% and 71.4%, respectively. No significant difference was found between the groups with regard to intraocular pressure, or success or complication rates.Conclusion: The results of trabeculectomy using single sutures or releasable sutures are equivalent. Therefore, the choice of suture technique should be based on individual patient requirements and surgeon experience.Keywords: glaucoma surgery, trabeculectomy, releasable suture, laser suture lysis

  17. Radiation treatment of polypropylene

    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

  18. Biodegradation of Polypropylene Nonwovens

    Keene, Brandi Nechelle

    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

  19. Development of lens sutures.

    Kuszak, Jer R; Zoltoski, Rebecca K; Tiedemann, Clifford E

    2004-01-01

    Cylindrical map projections (CMPs) have been used for centuries as an effective means of plotting the features of a 3D spheroidal surfaces (e.g. the earth) on a 2D rectangular map. We have used CMPs to plot primate fiber cell organization from selected growth shells as a function of growth, development and aging. Lens structural parameters and features were derived from slit-lamp, light and transmission and scanning electron micrographs. This information was then used to create CMPs of lenses that were then correlated with azimuthal map projections (AMPs; projections that are radially symmetric around a central point [the poles]) to reveal different suture patterns during distinct time periods. In this manner, both lens fiber and suture branch locations are defined by degrees of longitude and latitude. CMPs and AMPs confirm that throughout defined periods of development, growth and ageing, increasingly complex suture patterns are formed by the precise ordering of straight and opposite end curvature fibers. However, the manner in which additional suture branches are formed anteriorly and posteriorly is not identical. Anteriorly, new branches are added between extant branches. Posteriorly, pairs of new branches are formed that progressively overlay extant branches. The advantage of using CMPs is that the shape and organization of every fiber in a growth shell can be observed in a single image. Thus, the use of CMPs to plot primate fiber cell organization has revealed more complex aspects of fiber formation that may explain, at least in part, changes in lens optical quality as a function of age and pathology. In addition, more accurate measurements of fiber length will be possible by incorporating the latitudinal and longitudinal locations of fibers. PMID:15558480

  20. Stress-Softening and Residual Strain Effects in Suture Materials

    Alex Elías-Zúñiga

    2013-01-01

    Full Text Available This work focuses on the experimental characterization of suture material samples of MonoPlus, Monosyn, polyglycolic acid, polydioxanone 2–0, polydioxanone 4–0, poly(glycolide-co-epsilon-caprolactone, nylon, and polypropylene when subjected to cyclic loading and unloading conditions. It is found that all tested suture materials exhibit stress-softening and residual strain effects related to the microstructural material damage upon deformation from the natural, undistorted state of the virgin suture material. To predict experimental observations, a new constitutive material model that takes into account stress-softening and residual strain effects is developed. The basis of this model is the inclusion of a phenomenological nonmonotonous softening function that depends on the strain intensity between loading and unloading cycles. The theory is illustrated by modifying the non-Gaussian average-stretch, full-network model to capture stress-softening and residual strains by using pseudoelasticity concepts. It is shown that results obtained from theoretical simulations compare well with suture material experimental data.

  1. Comparison of Subcuticular Suture Materials in Cesarean Skin Closure

    Pınar Solmaz Hasdemir

    2015-01-01

    Full Text Available Aim. Comparison of the rate of wound complications, pain, and patient satisfaction based on used subcuticular suture material. Methods. A total of 250 consecutive women undergoing primary and repeat cesarean section with low transverse incision were prospectively included. The primary outcome was wound complication rate including infection, dehiscence, hematoma, and hypertrophic scar formation within a 6-week period after operation. Secondary outcomes were skin closure time, the need for use of additional analgesic agent, pain score on numeric rating scale, cosmetic score, and patient scar satisfaction scale. Results. Absorbable polyglactin was used in 108 patients and nonabsorbable polypropylene was used in 142 patients. Wound complication rates were similar in primary and repeat cesarean groups based on the type of suture material. Skin closure time is longer in nonabsorbable suture material group in both primary and repeat cesarean groups. There was no difference between groups in terms of postoperative pain, need for additional analgesic use, late phase pain, and itching at the scar. Although the cosmetic results tended to be better in the nonabsorbable group in primary surgery patients, there was no significant difference in the visual satisfaction of the patients. Conclusions. Absorbable and nonabsorbable suture materials are comparable in cesarean section operation skin closure.

  2. Introduction to sutured Floer homology

    Altman, Irida

    2013-01-01

    This article is a standalone introduction to sutured Floer homology for graduate students in geometry and topology. It is divided into three parts. The first part is an introductory level exposition of Lagrangian Floer homology. The second part is a construction of Heegaard Floer homology as a special, and slightly modified, case of Lagrangian Floer homology. The third part covers the background on sutured manifolds, the definition of sutured Floer homology, as well as a discussion of its mos...

  3. Selective suture cutting for control of astigmatism following cataract surgery

    Bansal R; Gupta Amod; Grewal SPS

    1992-01-01

    Use of 10-0 monofilament nylon in ECCE cataract surgery leads to high with the rule astigmatism. Many intraoperative and post operative methods have been used to minimise post operative astigmatism. We did selective suture cutting in 38 consecutive patients. Mean keratometric astigmatism at three and six weeks post operative was 5.76 and 5.42 dioptres (D) respectively. 77.5% of eyes had astigmatism above 2 D. Selective suture cutting along the axis of the plus high cylinder was done af...

  4. Advances in polypropylene based materials

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

  5. Fiber reinforced polypropylene nanocomposites

    Houphouet-Boigny, Chrystèle

    2007-01-01

    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...

  6. Fiber reinforced polypropylene nanocomposites

    Houphouet-Boigny, Chrystèle; Månson, Jan-Anders E.; Plummer, John Christopher

    2008-01-01

    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...

  7. Force sensing in surgical sutures

    Horeman, T.; Meijer, E. J.; Harlaar, J. J.; Lange, J.F.; Van den Dobbelsteen, J.J.; Dankelman, J.

    2013-01-01

    The tension in a suture is an important factor in the process of wound healing. If there is too much tension in the suture, the blood flow is restricted and necrosis can occur. If the tension is too low, the incision opens up and cannot heal properly. The purpose of this paper is to describe the design and evaluation of the Stitch Force (SF) sensor and the Hook-In Force (HIF) sensor. These sensors were developed to measure the force on a tensioned suture inside a closed incision and to measur...

  8. Force sensing in surgical sutures

    Horeman, Tim; Meijer, Evert-jan; Harlaar, Jaap; Lange, Johan; Dobbelsteen, John; Dankelman, Jenny

    2013-01-01

    textabstractThe tension in a suture is an important factor in the process of wound healing. If there is too much tension in the suture, the blood flow is restricted and necrosis can occur. If the tension is too low, the incision opens up and cannot heal properly. The purpose of this paper is to describe the design and evaluation of the Stitch Force (SF) sensor and the Hook-In Force (HIF) sensor. These sensors were developed to measure the force on a tensioned suture inside a closed incision a...

  9. Force Sensing in Surgical Sutures

    2013-01-01

    The tension in a suture is an important factor in the process of wound healing. If there is too much tension in the suture, the blood flow is restricted and necrosis can occur. If the tension is too low, the incision opens up and cannot heal properly. The purpose of this paper is to describe the design and evaluation of the Stitch Force (SF) sensor and the Hook-In Force (HIF) sensor. These sensors were developed to measure the force on a tensioned suture inside a closed incision and to measur...

  10. CORNEAL ASTIGMATISM AFTER ECCE: A COMPARATIVE STUDY BETWEEN SILK VERSUS NYLON SUTURE

    Sunita

    2013-11-01

    Full Text Available ABSTRAC T: INTRODUCTION: Cataract as a potent cause of loss of vision in old age persons is probably known since the dawn of human civilization. Post operative astigmatism after cataract extraction remains a big problem for cataract surgeons since Jacques Daviel e ra. Astigmatism is that type of refractive anomaly in which no point focus is formed owing to the unequal refraction of the incident light by the diopteric system of the eye in different meridians. The goal of modern cataract surgery is to produce a pseudo phakic with the quality of vision of a normal phakic eye. Various studies to find out any effect of IOL on post operative astigmatism were carried out but results are controversial. MATERIAL AND METHODS: 60 patients suffering from cataract and fit for extr action were enlisted during the month of August 2008 to February 2009. The general, physical and local examination including preoperative Keratometry, vision and tension were recorded. RESULTS: In the present study, male patients were 38 (63% and female p atients were 22 (37%. Out of the total 60 cases studied, corneo - scleral section of 28 cases (47% were sutured with 10 - 0 nylon suture (Group A while sections of 32 cases were sutured with 8 - 0 black virgin silk suture (Group B.Out of 28 cases of Group A, interrupted sutures were applied in 14 cases (50% (Group A 1 . Cross interrupted sutures were applied in 9 cases (32% Group A 2 , while bootlace continuous sutures were applied in 5 cases (18% (Group A 3 . Out of 32 cases of Group B, interrupted sutures we re applied in 26 cases (80% (Group B 1 , cross interrupted were applied in 3 cases (10% (Group B 2 , while bootlace continuous suture were applied in 3 cases (Group B 3 . In the present series, 19 cases (31% showed with the rule astigmatism, 21 cases (36% showed astigmatism against the rule and 20 cases (33% showed no astigmatism preoperatively, 16 cases were in the range of 0.50D to 1.0D and 12 cases were in the range of 1.0

  11. Microindentation of oriented polypropylene

    Lo, James C. W.

    The thesis focuses on the measurement of conventional engineering mechanical properties like yield strength, and dynamic mechanical (viscoelastic) properties of polymers using microindentation. In order to obtain high spatial resolutions, a flat punch indenter with a relatively small diameter of 80 mum was used. The present work emphasizes anisotropic materials: in particular oriented polypropylene. The initial test material was prepared by two solid state forming processes: uniaxial tensile drawing at elevated temperatures, and channel die forming. The latter allowed for greater control of the deformation ratio during forming over a much wider range of tensile strains. The mechanism of deformation under the tip of the indenter was studied using optical microscopy of thin sections viewed in transmission. The deep penetration mechanism changed with direction of indentation relative to the orientation axis. The observations were consistent with the mechanisms observed for unidirectional fiber reinforced composites. In particular, when penetrated parallel to the orientation direction, sharply defined zones of deformation which were similar to kink bands seen in compressed composites were seen. Detailed analysis of this behaviour showed that a modified version of the kink band formation theories developed for fiber composites could be successfully applied to oriented polypropylene. To confirm this, experiments on oriented polypropylene were compared to similar experiments on unidirectional carbon fiber reinforced epoxy. The development of deformation during deep penetration could be monitored by using a dynamic mechanical test which measured the stress amplitude response to an applied oscillating strain. One possible interpretation of these experimental observations involved the progressive development of the kink band deformation structure as the indenter was pushed into the material. The results of the first part of the thesis were used in a practical application

  12. U10.0 Undulator conceptual design report

    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

  13. Durable superoleophobic polypropylene surfaces.

    Brown, Philip S; Bhushan, Bharat

    2016-08-01

    Polypropylene (PP) is a popular plastic material used in consumer packaging. It would be desirable if such plastic containers were liquid repellent and not so easily fouled by their contents. Existing examples of superoleophobic surfaces typically rely on poorly adhered coatings or delicate surface structures, resulting in poor mechanical durability. Here, we report a facile method for creating superoleophobic PP surfaces via incorporation of nanoparticles (NPs) into the polymer surface. A solvent-NP-PP mixture was spin coated at high temperature to achieve the necessary roughness. Such surfaces were further functionalized with fluorosilane to result in a durable, super-repellent surface. They were also found to exhibit some repellency towards shampoos. This method of incorporating NPs into polymer surfaces could also prove useful in improving the anti-bacterial, mechanical and liquid-repellent properties of plastic devices.This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'. PMID:27354730

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

    Hennessey, D B

    2012-08-01

    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.

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

    Klink Christian D

    2011-12-01

    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.

  16. Unusual sutural bones at pterion

    Nayak SB; KV S

    2008-01-01

    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.

  17. Graft Suturing for Lenticule Dislocation after Descemet Stripping Automated Endothelial Keratoplasty

    Wai-Kwan Wu

    2011-01-01

    Full Text Available Purpose: To report the mid-term outcomes of graft suturing in a patient with lenticule dislocation after Descemet stripping automated endothelial keratoplasty (DSAEK. Case Report: A 78-year old woman was found to have graft dislocation involving the nasal half of the cornea after uneventful DSAEK. Graft repositioning, refilling the anterior chamber with air, and placement of four full-thickness 10/0 nylon sutures over the detached area were performed two weeks after the initial surgery. The sutures were removed 6 weeks later. Serial specular microscopy and anterior segment optical coherence tomography were performed. At 18 months, there was good lenticule apposition and a clear graft. Conclusion: Anchoring sutures seem to be effective for management of graft detachment following DSAEK.

  18. A modified suture placement technique to avoid suture drag or "cheese wire" effect.

    Cravy, T V

    1980-05-01

    A modified technique is described for microsurgical suture placement, irrespective of the closure technique, to prevent suture drag and loosening of the suture following postoperative wound edema. Fine, elastic, non-absorbable sutures which loosen as a result of suture drag or "cheese wiring" have no more reliability than do absorbable or silk sutures. Predictable and reproducible results of suture placement are necessary to allow the surgeon to effectively use the operating keratometer in the control and modification of corneal astigmatism following anterior segment surgery. PMID:6992018

  19. Suture materials - Current and emerging trends.

    Dennis, Christopher; Sethu, Swaminathan; Nayak, Sunita; Mohan, Loganathan; Morsi, Yosry Yos; Manivasagam, Geetha

    2016-06-01

    Surgical sutures are used to facilitate closure and healing of surgical- or trauma-induced wounds by upholding tissues together to facilitate healing process. There is a wide range of suture materials for medical purpose and the main types include absorbable and nonabsorbable. Recently, there is a growth in the development of classes of suture materials based on their properties and capabilities to improve tissue approximation and wound closure. This review outlines and discusses the current and emerging trends in suture technology including knotless barbed sutures, antimicrobial sutures, bio-active sutures such as drug-eluting and stem cells seeded sutures, and smart sutures including elastic, and electronic sutures. These newer strategies expand the versatility of sutures from being used as just a physical entity approximating opposing tissues to a more biologically active component enabling delivery of drugs and cells to the desired site with immense application potential in both therapeutics and diagnostics. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1544-1559, 2016. PMID:26860644

  20. Argon plasma irradiation of polypropylene

    Vasina, A.; Malinský, Petr; Slepička, P.; Macková, Anna; Švorčík, V.

    Cambridge: IOP, Institute of physics, 2009. s. 83-83. [19th International conference on Ion beam analysis . 07.09.2009-11.09.2009, Cambridge] R&D Projects: GA MŠk(CZ) LC06041 Institutional research plan: CEZ:AV0Z10480505 Keywords : polypropylene * plasma treatment * RBS * XPS * zeta potential Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  1. Torrefied biomass-polypropylene composites

    Torrefied almond shells and wood chips were incorporated into polypropylene as fillers to produce torrefied biomass-polymer composites. Response surface methodology was used to examine the effects of filler concentration, filler size, and lignin factor (relative lignin to cellulose concentration) on...

  2. New adjustable suture technique for trabeculectomy

    Vespasiano Rebouças-Santos

    2013-06-01

    Full Text Available PURPOSE: To describe an adjustable suture (AS experimental model that allows for tightening, loosening and retightening of the suture tension in trabeculectomy. METHODS: Standard trabeculectomy was performed in fifteen pig eyeballs. All pig eyes were tested twice: one test with conventional suture in both flap's corners (conventional suture group and another test with a conventional suture at one corner and an adjustable suture in the other corner (AS group. The order in which each test was performed was defined by randomization. Intraocular pressure was measured at three time points: T1 when the knots were tightened; T2 when the AS was loosened or the conventional knot was removed; and T3 when the AS was retightened in the AS group or five minutes after the knot removal in the conventional suture group. RESULTS: The mean Intraocular pressure was similar between the two groups at time point 1 (p=0.97. However, significant Intraocular pressure differences were found between eyes in the conventional and adjustable suture groups at time points 2 (12.6 ± 4.2 vs 16.3 ± 2.3 cmH2O, respectively, p=0.006 and 3 (12.2 ± 4.0 vs 26.4 ± 1.7cmH2O, respectively; p=0.001. While the conventional technique allowed only Intraocular pressure reduction (following the knot removal; T2 and T3, the AS technique allowed both Intraocular pressure reduction (T2 and elevation (T3 through the management (loosening and retightening of the suture. CONCLUSION: This experimental model provides an effective noninvasive postoperative mechanism of suture tension adjustment.

  3. Woodflour as Reinforcement of Polypropylene

    José Cláudio Caraschi

    2002-10-01

    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.

  4. Lifting and wound closure with barbed sutures.

    Mulholland, R Stephen; Paul, Malcolm D

    2011-07-01

    The advent of barbed sutures has been a novel and useful adjunct for the aesthetic plastic surgeon in properly selected patients. The deployment of a barbed suture minimizes the risks of cheese wiring and stress relaxation, facilitating the minimally invasive repositioning of soft tissue in the head and neck, as well as optimizing and enhancing traditionally long and potentially tedious procedures in body contouring. This article highlights the advances, advantages, and efficacy associated with the use of barbed sutures in lifting and wound closure. PMID:21824547

  5. Production, characterization, and modeling of mineral filled polypropylene filaments

    George, Brian Robert

    1999-11-01

    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

  6. Suture slippage in knotless suture anchors resulting in subacromial-subdeltoid bursitis.

    Hayeri, Mohammad Reza; Keefe, Daniel T; Chang, Eric Y

    2016-05-01

    Rotator cuff repair using a suture bridge and knotless suture anchors is a relatively new, but increasingly used technique. The suture bridge technique creates an anatomically similar and more secure rotator cuff repair compared with conventional arthroscopic techniques and the use of knotless anchors eliminates the challenges associated with knot tying during arthroscopic surgery. However, previous in vitro biomechanical tests have shown that the hold of the suture in a knotless suture anchor is far lower than the pullout strength of the anchor from bone. Up until now slippage has been a theoretical concern. We present a prospectively diagnosed case of in vivo suture loosening after rotator cuff repair using a knotless bridge technique resulting in subacromial-subdeltoid bursitis. PMID:26739301

  7. Chronic complaints after simple sutured repair for umbilical or epigastric hernias may be related to recurrence

    Westen, Mikkel; Christoffersen, Mette W; Jorgensen, Lars N; Stigaard, Trine; Bisgaard, Thue

    2014-01-01

    % response rate). Up till 5.8 % of the patients reported moderate or severe pain and discomfort. Work and leisure activities were restricted in 8.5 and 10.0 % of patients, respectively. Patients with chronic complaints had a higher incidence of recurrence (clinical and reoperation), than patients with none...... repair was in the level of 5.5 % and could in part be explained by recurrence. Furthermore, absorbable suture should be omitted to reduce risk of recurrence....

  8. 21 CFR 878.4495 - Stainless steel suture.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Stainless steel suture. 878.4495 Section 878.4495...) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4495 Stainless steel suture. (a) Identification. A stainless steel suture is a needled or unneedled nonabsorbable surgical suture composed of...

  9. Frimand Needle Holder Reduces Suturing Time and Surgical Stress When Suturing in Palm Grip.

    Frimand Rönnow, Carl-Fredrik; Jeppsson, Bengt; Thorlacius, Henrik

    2016-06-01

    Purpose The Frimand needle holder (FNH) was developed to facilitate palm grip suturing. In the present study, we wanted to examine the impact of the FNH compared with a conventional Hegar-styled needle holder (HSNH) on suture time and surgical stress. Methods Thirty-two surgeons were enrolled and they performed sets of 3 continuous sutures on a polyurethane pad with premarked insert and exit points and the time for suturing was measured. Surgical stress was quantified by having the surgeons to perform 10 release maneuvers with the FNH and the HSNH on a needle attached to a scale. The scale sent 5 values per second to a computer. The first measurement of each series was regarded as the starting weight and all subsequent measurements were either regarded as neutral, pressure or traction. The sum of these measurements represented total surgical stress. Results We found that all surgeons reduced their median suturing time by 16% when using FNH for palm grip suturing with no difference between junior and senior surgeons. Moreover, it was observed that FNH decreased median surgical stress by 62% for all surgeons performing palm grip suturing compared with a conventional HSNH. Conclusion We conclude that the FNH reduces suture time and surgical stress compared with HSNH when performing palm grip suturing. These findings warrant studies in surgical patients in order to evaluate the potential clinical impact of FNH. PMID:26474606

  10. Dyeing of Polypropylene Fibers with Vat Dyes

    LIU Hang; ETTERS J. Nolan; LEONAS Karen K

    2006-01-01

    Polypropylene fibers have been extensively used in a variety of products, including carpets and upholstery, due to their non-absorbency, good weather resistance, good resistance to microorganisms and so on. Because of their hydrophobic and highly crystalline nature, those well-established conventional dyeing processes are difficult to apply to unmodified polypropylene. Colors of polypropylene fibers are primarily obtained by mass coloration which has the disadvantages of limited number of colors available and difficulties in inventory control due to the rapidly changing color needs of the market. In this paper, the use of vat dyes to dye polypropylene fabrics is investigated. Seventeen vat dyes were screened and factors influencing uptake of dyes by polypropylene fabrics were studied.

  11. Subscapularis Tendon Repair Using Suture Bridge Technique

    Park, Yong Bok; Park, Young Eun; Koh, Kyoung Hwan; Lim, Tae Kang; Shon, Min Soo; Yoo, Jae Chul

    2015-01-01

    The subscapularis tendon plays an essential role in shoulder function. Although subscapularis tendon tears are less common than other rotator cuff tears, tears of the subscapularis tendon have increasingly been recognized with the advent of magnetic resonance imaging and arthroscopy. A suture bridge technique for the treatment of posterosuperior rotator cuff tears has provided the opportunity to improve the pressurized contact area and mean footprint pressure. However, suture bridge fixation ...

  12. Argon plasma irradiation of polypropylene

    Slepička, P.; Vasina, A.; Kolská, Z.; Luxbacher, T.; Malinský, Petr; Macková, Anna; Švorčík, V.

    2010-01-01

    Roč. 268, 11-12 (2010), s. 2111-2114. ISSN 0168-583X. [19th International conference on Ion beam analysis. Cambridge, 07.09.2009-11.09.2009] R&D Projects: GA ČR GA106/09/0125; GA MŠk(CZ) LC06041; GA AV ČR(CZ) KAN400480701 Institutional research plan: CEZ:AV0Z10480505 Keywords : Polypropylene * Plasma treatment * RBS Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.042, year: 2010

  13. Effects of primary suture and fibrin sealant on hemostasis and liver regeneration in an experimental liver injury

    Arif Hakan Demirel; Ozgur Taylan Basar; All Ulvi Ongoren; Erkut Bayram; Mustafa Kisakurek

    2008-01-01

    AIM:To investigate the effects of fibrin 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), fibrin 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 fibrin glue was administrated on the liver surface in fibrin sealant group.RESULTS: More intra-abdominal adhesions were observed in the primary suture group compared to the fibrin sealant group on 3rd (2.50.5 vs 0.25.5, P =0.015), 10th(2.75.5 vs 0.50.6, P = 0.06) and 20th(1.75.5 vs 0.70.5, P = 0.015) postoperative days. Histopathological scores were better in the fibrin sealant group in comparison with the primary suture group on 3rd (8.75.5 vs 6.75.5, P = 0.006), 10th (7.50.0 vs 5.5.6, P = 0.021) and 20th(6.40.7 vs 3.20.6, P = 0.025) postoperative days.CONCLUSION: Out data suggest that fibrin 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.

  14. Experimental study of the characteristics of a novel mesh suture

    Dumanian, G. A.; Tulaimat, A.; Dumanian, Z. P.

    2015-01-01

    Background The failure of sutures to maintain tissue in apposition is well characterized in hernia repairs. A mesh suture designed to facilitate tissue integration into and around the filaments may improve tissue hold and decrease suture pull‐through. Methods In vitro, the sutures were compared for resistance to pull‐through in ballistics gel. In vivo, closure of midline laparotomy incisions was done with both sutures in 11 female pigs. Tissue segments were subsequently subjected to mechanica...

  15. Modification of Nanocomposites by Melting Intercalation of Polypropylene in Montmorillonite

    2002-01-01

    The polypropylene was modified by ultraviolet irradiation.The polypropylene-montmorillonite nanocomposites were prepared by direct melting intercalation of polypropylene powders.The structure of polypropylene,the polyproprlene irradiated, montmorillinote and polypropylene-montmorillonite composites were studied by XRD, IR and DSC. The results show that the PP molecules can are oxidized during ultraviolet irradiation,melt polypropylene can intercalate into montmorillonite layer.As a result,the layered distance (d001) of montmorillonite increases, and the melt absorption peak of polypropylene in layer is eliminated.

  16. Modified method for bronchial suture by Ramirez Gama compared to separate stitches suture: experimental study

    Vitor Mayer de Moura

    2014-06-01

    Full Text Available OBJECTIVE: To experimentally compare two classic techniques described for manual suture of the bronchial stump. METHODS: We used organs of pigs, with isolated trachea and lungs, preserved by refrigeration. We dissected 30 bronchi, which were divided into three groups of ten bronchi each, of 3mm, 5mm, and 7mm, respectively. In each, we performed the suture with simple, separated, extramucosal stitches in five other bronchi, and the technique proposed by Ramirez and modified by Santos et al in the other five. Once the sutures were finished, the anastomoses were tested using compressed air ventilation, applying an endotracheal pressure of 20mmHg. RESULTS: the Ramirez Gama suture was more effective in the bronchi of 3, 5 and 7 mm, and there was no air leak even after subjecting them to a tracheal pressure of 20mmHg. The simple interrupted sutures were less effective, with extravasation in six of the 15 tested bronchi, especially in the angles of the sutures. These figures were not significant (p = 0.08. CONCLUSION: manual sutures of the bronchial stumps were more effective when the modified Ramirez Gama suture was used in the caliber bronchi arms when tested with increased endotracheal pressure.

  17. Mechanical performance of gamma irradiated surgical sutures

    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)

  18. Multiaxial yield behaviour of polypropylene

    Lang R.

    2010-06-01

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

  19. When Polypropylene Fiber Can Be Dyed

    By Tom Xue

    2008-01-01

    @@ What if polypropylene fiber can be dyed someday? That means fiber offers immense production possibilities,means manufacturers will benefit from increasing their operational effectiveness,reducing the inventory of colored yarns,means streamline production process,means……

  20. Sutured Floer homology distinguishes between Seifert surfaces

    Altman, Irida

    2010-01-01

    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.

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

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

    2012-01-02

    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.

  2. Comparison of suture types in the closure of scalp wounds.

    Bonham, Joseph

    2011-06-01

    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.

  3. Aortic valve annuloplasty: new single suture technique.

    Schöllhorn, Joachim; Rylski, Bartosz; Beyersdorf, Friedhelm

    2014-06-01

    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

  4. Biomechanical Dynamics of Cranial Sutures during Simulated Impulsive Loading.

    Zhang, Z Q; Yang, J L

    2015-01-01

    Background. Cranial sutures are deformable joints between the bones of the skull, bridged by collagen fibres. They function to hold the bones of the skull together while allowing for mechanical stress transmission and deformation. Objective. The aim of this study is to investigate how cranial suture morphology, suture material property, and the arrangement of sutural collagen fibres influence the dynamic responses of the suture and surrounding bone under impulsive loads. Methods. An idealized bone-suture-bone complex was analyzed using a two-dimensional finite element model. A uniform impulsive loading was applied to the complex. Outcome variables of von Mises stress and strain energy were evaluated to characterize the sutures' biomechanical behavior. Results. Parametric studies revealed that the suture strain energy and the patterns of Mises stress in both the suture and surrounding bone were strongly dependent on the suture morphologies. Conclusions. It was concluded that the higher order hierarchical suture morphology, lower suture elastic modulus, and the better collagen fiber orientation must benefit the stress attenuation and energy absorption. PMID:27019589

  5. Elastic behaviour of sutured calf pericardium: influence of the suture threads.

    García Páez, J M; Carrera San Martin, A; García Sestafe, J V; Jorge Herrero, E; Navidad, R; Cordón, A; Castillo-Olivares, J L

    1996-09-01

    The purpose of this study was to assess the elastic behaviour of calf pericardium used in the construction of cardiac bioprosthesis valve leaflets, sutured with different types of commercially available sutures: silk, Gore-Tex, Surgilene and nylon. Thirty-two samples (four series of eight samples each) were subjected to tensile strength testing to breakage. The breaking stress (MPa) ranged between 4.89 MPa for samples sutured with Gore-Tex and 5.22 MPa for those sewn with nylon. Three samples from each series were subjected to a stepwise stress test, involving increasing levels of stress followed by return to zero, to define the elastic limit (the cut-off point beyond which strain is no longer reversible). Analysis of the results provided the mathematical functions that govern the elastic behaviour (stress/strain) within the elastic range for each type of sutured sample. The series sutured with Surgilene presented the highest mean value (1.649 MPa). Finally, a statistical study was carried out to determine which series showed the greatest probability of having the least interaction between the thread and the pericardium. Allowing an interval of +/- 10%, Gore-Tex showed the best probability in this respect. However, real fatigue testing is necessary to definitively determine which is the best suture to use. PMID:8866029

  6. Aksa plans polypropylene joint venture

    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

  7. Argon plasma irradiation of polypropylene

    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.

  8. Automatic Detection of Wild-type Mouse Cranial Sutures

    Ólafsdóttir, Hildur; Darvann, Tron Andre; Hermann, Nuno V.;

    , automatic detection of the cranial sutures becomes important. We have previously built a craniofacial, wild-type mouse atlas from a set of 10 Micro CT scans using a B-spline-based nonrigid registration method by Rueckert et al. Subsequently, all volumes were registered nonrigidly to the atlas. Using these...... observer traced the sutures on each of the mouse volumes as well. The observer outperforms the automatic approach by approximately 0.1 mm. All mice have similar errors while the suture error plots reveal that suture 1 and 2 are cumbersome, both for the observer and the automatic approach. These sutures can...

  9. Suturas mecânicas Mechanic sutures

    Alexandre Miranda Duarte

    2002-10-01

    Full Text Available The authors review the use of staplers in General Surgery, mainly in Gastroenterological Surgery highlighting safety and effectiveness. They emphasize that the mechanic anastomosis are a viable technique and in some conditions, the best way to perform the anastomosis. The use of staplers makes surgery faster and easier and complications are, generally related to surgeon's experience in using them. Although its costs are higher compared to handsewn suture, it can make the patient total cost lower.

  10. Skin tension related to tension reduction sutures.

    Hwang, Kun; Kim, Han Joon; Kim, Kyung Yong; Han, Seung Ho; Hwang, Se Jin

    2015-01-01

    The aim of this study was to compare the skin tension of several fascial/subcutaneous tensile reduction sutures. Six upper limbs and 8 lower limbs of 4 fresh cadavers were used. At the deltoid area (10 cm below the palpable acromion) and lateral thigh (midpoint from the palpable greater trochanter to the lateral border of the patella), and within a 3 × 6-cm fusiform area of skin, subcutaneous tissue defects were created. At the midpoint of the defect, a no. 5 silk suture was passed through the dermis at a 5-mm margin of the defect, and the defect was approximated. The initial tension to approximate the margins was measured using a tensiometer.The tension needed to approximate skin without any tension reduction suture (S) was 6.5 ± 4.6 N (Newton). The tensions needed to approximate superficial fascia (SF) and deep fascia (DF) were 7.8 ± 3.4 N and 10.3 ± 5.1 N, respectively. The tension needed to approximate the skin after approximating the SF was 4.1 ± 3.4 N. The tension needed to approximate the skin after approximating the DF was 4.9 ± 4.0 N. The tension reduction effect of approximating the SF was 38.8 ± 16.4% (2.4 ± 1.5 N, P = 0.000 [ANOVA, Scheffé]). The tension reduction effect of approximating the DF was 25.2% ± 21.9% (1.5 ± 1.4 N, P = 0.001 [ANOVA, Scheffé]). The reason for this is thought to be that the SF is located closely to the skin unlike the DF. The results of this study might be a basis for tension reduction sutures. PMID:25569413

  11. Internal friction studies of particulate filled polypropylene

    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 α- and α'-relaxation were found while no peak of the β-relaxation was detected. At high temperatures a drastic increase of the loss factor superposes the α'-peak. The crystallinity of the filled polypropylene varies in the range from 23% to 35%. The samples consist of α- and β-crystallites depending on the material and amount of filler

  12. Electret Stability Related to Spherulites in Polypropylene

    Thyssen, Anders; Almdal, Kristoffer; Thomsen, Erik Vilain

    2015-01-01

    Electret charge stability has been related to the size of the spherulites in polypropylene. As the size of the spherulites is decreased the stability is increased. This is seen for isothermal conditions at 90 °C and 120 °C as well as for 90 % relative humidity at 50 °C. The charge release...... temperature is also increased in thermally stimulated voltage discharge experiments as the size of the spherulites is decreased. The size of the spherulites is controlled though the cooling rate from polypropylenes liquid state....

  13. Suture locking of isolated internal locking knotless suture anchors is not affected by bone quality

    Woodmass JM

    2015-06-01

    Full Text Available Jarret M Woodmass,1 Graeme Matthewson,1 Yohei Ono,1,2 Aaron J Bois,1 Richard S Boorman,1 Ian KY Lo,1 Gail M Thornton1,31Department of Surgery, Section of Orthopaedic Surgery, McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB, Canada; 2Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan; 3Department of Orthopaedics, University of British Columbia, Vancouver, BC, Canada Purpose: The purpose of this study was to evaluate the mechanical performance of different suture locking mechanisms including: i interference fit between the anchor and the bone (eg, 4.5 mm PushLock, 5.5 mm SwiveLock, ii internal locking mechanism within the anchor itself (eg, 5.5 mm SpeedScrew, or iii a combination of interference fit and internal locking (eg, 4.5 mm MultiFIX P, 5.5 mm MultiFIX S. Methods: Anchors were tested in foam blocks representing normal (20/8 foam or osteopenic (8/8 foam bone, using standard suture loops pulled in-line with the anchor to isolate suture locking. Mechanical testing included cyclic testing for 500 cycles from 10 N to 60 N at 60 mm/min, followed by failure testing at 60 mm/min. Displacement after 500 cycles at 60 N, number of cycles at 3 mm displacement, load at 3 mm displacement, and maximum load were evaluated. Results: Comparing 8/8 foam to 20/8 foam, load at 3 mm displacement and maximum load were significantly decreased (P<0.05 with decreased bone quality for anchors that, even in part, relied on an interference fit suture locking mechanism (ie, 4.5 mm PushLock, 5.5 mm SwiveLock, 4.5 mm MultiFIX P, 5.5 mm MultiFIX S. Bone quality did not affect the mechanical performance of 5.5 mm SpeedScrew anchors which have an isolated internal locking mechanism. Conclusion: The mechanical performance of anchors that relied, even in part, on interference fit were affected by bone quality. Isolated internal locking knotless suture anchors functioned independently of bone quality

  14. Fiber from ramie plant (Boehmeria nivea): A novel suture biomaterial.

    Kandimalla, Raghuram; Kalita, Sanjeeb; Choudhury, Bhaswati; Devi, Dipali; Kalita, Dhaneswar; Kalita, Kasturi; Dash, Suvakanta; Kotoky, Jibon

    2016-05-01

    The quest for developing an ideal suture material prompted our interest to develop a novel suture with advantageous characters to market available ones. From natural origin only silk, cotton and linen fibers are presently available in market as non-absorbable suture biomaterials. In this study, we have developed a novel, cost-effective, and biocompatible suture biomaterial from ramie plant, Boehmeria nivea fiber. Field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and thermo gravimetric analysis (TGA) results revealed the physicochemical properties of raw and degummed ramie fiber, where the former one showed desirable characteristics for suture preparation. The braided multifilament ramie suture prepared from degummed fiber exhibited excellent tensile strength. The suture found to be biocompatible towards human erythrocytes and nontoxic to mammalian cells. The fabricated ramie suture exhibited significant antibacterial activity against Escherichia coli, Bacillus subtilis and Staphylococcus aureus; which can be attributed to the inherent bacteriostatic ability of ramie plant fiber. In vivo wound closure efficacy was evaluated in adult male wister rats by suturing the superficial wound incisions. Within seven days of surgery the wound got completely healed leaving no rash and scar. The role of the ramie suture in complete wound healing was supported by the reduced levels of serum inflammatory mediators. Histopathology studies confirmed the wound healing ability of ramie suture, as rapid synthesis of collagen, connective tissue and other skin adnexal structures were observed within seven days of surgery. Tensile properties, biocompatibility and wound closure efficacy of the ramie suture were comparable with market available BMSF suture. The outcome of this study can drive tremendous possibility for the utilization of ramie plant fiber for

  15. Cranial suture biology of the Aleutian Island inhabitants.

    Cray, James; Mooney, Mark P; Siegel, Michael I

    2011-04-01

    Research on cranial suture biology suggests there is biological and taxonomic information to be garnered from the heritable pattern of suture synostosis. Suture synostosis along with brain growth patterns, diet, and biomechanical forces influence phenotypic variability in cranial vault morphology. This study was designed to determine the pattern of ectocranial suture synostosis in skeletal populations from the Aleutian Islands. We address the hypothesis that ectocranial suture synostosis pattern will differ according to cranial vault shape. Ales Hrdlicka identified two phenotypes in remains excavated from the Aleutian Island. The Paleo-Aleutians, exhibiting a dolichocranic phenotype with little prognathism linked to artifacts distinguished from later inhabitants, Aleutians, who exhibited a brachycranic phenotype with a greater amount of prognathism. A total of 212 crania representing Paleo-Aleuts and Aleutian as defined by Hrdlicka were investigated for suture synostosis pattern following standard methodologies. Comparisons were performed using Guttmann analyses. Results revealed similar suture fusion patterns for the Paleo-Aleut and Aleutian, a strong anterior to posterior pattern of suture fusion for the lateral-anterior suture sites, and a pattern of early termination at the sagittal suture sites for the vault. These patterns were found to differ from that reported in the literature. Because these two populations with distinct cranial shapes exhibit similar patterns of suture synostosis it appears pattern is independent of cranial shape in these populations of Homo sapiens. These findings suggest that suture fusion patterns may be population dependent and that a standardized methodology, using suture fusion to determine age-at-death, may not be applicable to all populations. PMID:21328563

  16. Anastomose arterial com fio de polidioxanona e fio de polipropileno. Estudo comparativo em cães Arterial anastomose with polydioxanone and polypropilene suture. Comparative study in dogs

    Eloísa de Brida Tormena

    2002-03-01

    Full Text Available Este estudo teve por objetivo comparar os efeitos do fio absorvível de polidioxanona com o fio inabsorvível de polipropileno, em anastomoses término-terminais, em artérias femorais de cães. Foram utilizados 20 cães, separados em dois grupos, para observação no 7º e no 30º dia de pós-operatório. Cada cão teve suas artérias femorais seccionadas e aproximadas em um lado com pontos separados de fio de polidioxanona 6-0, e no lado contralateral com o fio de polipropileno 6-0. A escolha do fio foi feita por sorteio, totalizando 40 anastomoses. Para análise estatística dos resultados aplicaram-se os testes de Fisher, Mac Nemar, Wilcoxon, Mann-Witney e o teste T de Student (a ≤ 0,05. Nas avaliações clínicas não foram observadas diferenças significantes entre os fios utilizados. Os resultados obtidos nas avaliações arteriográfica e macroscópica dos segmentos arteriais foram semelhantes, assim como na análise histológica morfológica. Na análise histológica morfométrica o fio de polipropileno apresentou número de células gigantes de corpo estranho significativamente maior que o fio de polidioxanona aos 7 e 30 dias de pós-operatório. Os resultados nos permitem concluir que, apesar da maior reação de corpo estranho observada com o fio de polipropileno, o fio de polidioxanona apresentou resultados semelhantes ao fio de polipropileno, em anastomoses arteriais em cães.The objetive of this study was to compare the effects of the absorbable polidioxanone suture to the nonabsorbable polypropylene suture, in end-to-end anastomoses, using dog’s femoral arteries. Twenty dogs were separated in two groups for observation on the 7th and 30th post-operatory day. Each dog had its femoral arteries seccioned and then aproximated one side with separate stitches of polidioxanone 6-0 suture, and the other side with polypropylene 6-0 suture. For the statistical studies Fisher, Mac nemar, Wilsoxon, Mann-Witney and T of Student tests (a

  17. Polypropylene/aspen/liquid polybutadienes composites

    Kokta, B. V.; Fortelný, Ivan; Kruliš, Zdeněk; Michálková, Danuše

    Erfurt : Thüringisches Institut für Textil - und Kunststoff-Forschung e.V, 2005, S1-03/1-S1-03/7. [International Symposium on Materials /5./. Erfurt (DE), 01.09.2005-02.09.2005] Institutional research plan: CEZ:AV0Z40500505 Keywords : Polymer composites * cellulose fibers * polypropylene Subject RIV: CD - Macromolecular Chemistry

  18. Bioactivity of degradable polymer sutures coated with bioactive glass.

    Bretcanu, Oana; Verné, Enrica; Borello, Luisa; Boccaccini, Aldo R

    2004-08-01

    Novel bioactive materials have been prepared by coating violet resorbable Vicryl sutures with a bioactive glass powder derived from a co-precipitation method. Two techniques have been chosen for the composite preparation: pressing the sutures in a bed of glass powder and slurry-dipping of sutures in liquid suspensions of bioactive glass powders. The uniformity and thickness of the coatings obtained by the two methods were compared. The bioactivity of the sutures with and without bioactive glass coating was tested by soaking in an inorganic acellular simulated body fluid (SBF). The composite sutures were characterised by XRD, SEM and FTIR analyses before and after soaking in SBF solution to assess the formation of hydroxyapatite on their surfaces, which is a qualitative measure of their bioactivity. The possible use of bioactive sutures to produce tissue engineering scaffolds and as reinforcement of resorbable calcium phosphates is discussed. PMID:15477741

  19. The frontosphenoidal suture: fetal development and phenotype of its synostosis

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

    2008-04-15

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

  20. The frontosphenoidal suture: fetal development and phenotype of its synostosis

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

  1. A technique for introducing looped sutures in flexor tendon repair

    Kamath B

    2006-01-01

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

  2. Adjustable sutures in eyelid surgery for ptosis and lid retraction.

    Collin, J R; O'Donnell, B A

    1994-01-01

    New techniques are described and illustrated for ptosis and lid retraction surgery in which the sutures holding the upper eyelid position are adjustable postoperatively. In the anterior approach, the sutures pass from the levator muscle through the anterior surface of the tarsal plate at the position of the skin crease and are tied at the skin crease incision. In the posterior approach, the sutures pass from the levator muscle through the cut upper edge of the tarsal plate and are tied at the...

  3. Mechanics of cranial sutures during simulated cyclic loading.

    Jasinoski, S C; Reddy, B D

    2012-07-26

    Previous computational and experimental analyses revealed that cranial sutures, fibrous joints between the bones, can reduce the strain experienced by the surrounding skull bones during mastication. This damping effect reflects the importance of including sutures in finite element (FE) analyses of the skull. Using the FE method, the behaviour of three suture morphologies of increasing complexity (butt-ended, moderate interdigitated, and complex interdigitated) during static loading was recently investigated, and the sutures were assumed to have linear elastic properties. In the current study, viscoelastic properties, derived from published experimental results of the nasofrontal suture of young pigs (Sus scrofa), are applied to the three idealised bone-suture models. The effects of suture viscoelasticity on the stress, strain, and strain energy in the models were computed for three different frequencies (corresponding to periods of 1, 10, and 100s) and compared to the results of a static, linear elastic analysis. The range of applied frequencies broadly represents different physiological activities, with the highest frequency simulating mastication and the lowest frequency simulating growth and pressure of the surrounding tissues. Comparing across all three suture morphologies, strain energy and strain in the suture decreased with the increase in suture complexity. For each suture model, the magnitude of strain decreased with an increase in frequency, and the magnitudes were similar for both the elastic and 1s frequency analyses. In addition, a viscous response is less apparent in the higher frequency analyses, indicating that viscous properties are less important to the behaviour of the suture during those analyses. The FE results suggest that implementation of viscoelastic properties may not be necessary for computational studies of skull behaviour during masticatory loading but instead might be more relevant for studies examining lower frequency physiological

  4. The Effect of Anchoring Sutures on Medicinal Leech Mortality

    Davila, Victor J.; Hoppe, Ian C.; Landi, Rocco; Ciminello, Frank S.

    2009-01-01

    Objective: The implementation of leech therapy for surgical flaps is not always logistically easy or comfortable for patients or healthcare providers. We examine different methods of placing sutures in the medicinal leech, Hirudo medicinalis, to make the implementation of leech therapy easier. Methods: Sixteen leeches were randomly divided into 3 groups: a control group, a deep anchoring suture group, and a superficial anchoring suture group. The leeches were observed to determine if either o...

  5. A COMPARATIVE STUDY BETWEEN SURGICAL OUTCOME OF PATIENT’S OWN BLOOD VS. 10-0 NYLON FOR CONJUNCTIVAL AUTOGRAFTING IN PTERYGIUM EXCISION

    Ayush Mahendra

    2016-04-01

    Full Text Available CONTEXT (BACKGROUND Pterygium is a frequently occurring progressive ocular surface disorder which is a fleshy triangular wing shaped growth, encroaching from conjunctiva on cornea. Pterygium is frequent in hot, dry, dusty environment and prevalence is 0.3% to 29%. Surgical removal is main treatment for pterygium. The recurrence rate after pterygium surgery varies according to type of surgery. Various surgical modalities tried like simple excision, bare sclera technique, amniotic membrane transplantation and conjunctival autografting. AIM To compare surgical outcome of patient’s own blood Vs 10-0 Nylon for conjunctival autografting in pterygium excision. SETTINGS AND DESIGN It is a prospective randomised interventional control trial, with a sample size of minimum 30 patients in each group studied in a tertiary care hospital from Oct. 2013 to Dec. 2015. METHODS AND MATERIAL Out of 63 patients who underwent pterygium excision, patient’s own blood was used in 32 patients (Group A and 10-0 Nylon suture was used in 31 patients (Group B for conjunctival autografting. All patients were followed up regularly on postoperative day 1, 8, 30, 90 and 180. Variables for postoperative assessment were pain, watering, irritation, redness, graft displacement, graft loss and recurrence. STATISTICAL ANALYSIS Statistical analysis was performed using SPSS 13.0 (SPSS, Chicago. Outcome variables between the two groups were compared using the non-parametric Mann–Whitney U Test. RESULTS The mean surgical time of group B (31.48±6.15 min is significantly high as compared to group A (19.71±5.13 min with p<0.001. The regression analysis revealed that except surgery type, no other variable had significant impact on the duration of surgery. Postoperative symptoms are less in group A as compared to group B. Group B showed two recurrences whereas no recurrence was seen in group A. CONCLUSIONS Conjunctival autografting by patient’s own blood is better than 10-0 Nylon

  6. Radioactive suture in the treatment of head and neck cancer

    125I 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 125I impregnated Vicryl suture in this manner appears to produce improved long-term palliation and may increase local cure rates

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

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

    2013-10-01

    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.

  8. Surgical device for supporting corneal suturing

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

    2009-02-01

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

  9. The Mechanical Properties of Polypropylene Fiber Reinforced Concrete

    LI Bei-xing; CHEN Ming-xiang; CHENG Fang; LIU Lu-ping

    2004-01-01

    The compressive, shear strengths and abrasion-erosion resistance as well as flexural properties of two polypropylene fiber reinforced concretes and the comparison with a steel fiber reinforced concrete were reported.The exprimental results show that a low content of polypropylene fiber (0.91kg/m3 of concrete) slightly decreases the compressive and shear strengths, and appreciably increased the flexural strength, but obviously enhances the toughness index and fracture energy for the concrete with the same mix proportion, consequently it plays a role of anti-cracking and improving toughness in concrete. Moreover, the polypropylene mesh fiber is better than the polypropylene monofilament fiber in improving flexural strength and toughness of concrete, but the two types of polypropylene fibers are inferior to steel fiber. All the polypropylene and steel fibers have no great beneficial effect on the abrasion-erosion resistance of concrete.

  10. Texturing of polypropylene (PP) with nanosecond lasers

    Riveiro, A.; Soto, R.; del Val, J.; Comesaña, R.; Boutinguiza, M.; Quintero, F.; Lusquiños, F.; Pou, J.

    2016-06-01

    Polypropylene (PP) is a biocompatible and biostable polymer, showing good mechanical properties that has been recently introduced in the biomedical field for bone repairing applications; however, its poor surface properties due to its low surface energy limit their use in biomedical applications. In this work, we have studied the topographical modification of polypropylene (PP) laser textured with Nd:YVO4 nanosecond lasers emitting at λ = 1064 nm, 532 nm, and 355 nm. First, optical response of this material under these laser wavelengths was determined. The application of an absorbing coating was also studied. The influence of the laser processing parameters on the surface modification of PP was investigated by means of statistically designed experiments. Processing maps to tailor the roughness, and wettability, the main parameters affecting cell adhesion characteristics of implants, were also determined. Microhardness measurements were performed to discern the impact of laser treatment on the final mechanical properties of PP.

  11. Elevated temperature concrete curing - using polypropylene fibres

    Richardson, Alan; Coventry, Kathryn; Morgan, Miles

    2011-01-01

    This paper examines cement hydration when concrete cures at elevated temperatures with and without the addition of Type 1 polypropylene fibres and addresses some of the ambiguities that have arisen from previous research. Paired comparison tests were carried out to compare density, strength, pulse velocity, and absorption using plain and fibre concrete at ambient UK indoor temperatures, compared to concrete at elevated temperatures that would be found in The Middle East. The results ...

  12. Residual stress distribution in extruded polypropylene pipes

    Poduška, Jan; Kučera, J.; Hutař, Pavel; Ševčík, Martin; Křivánek, J.; Sadílek, J.; Náhlík, Luboš

    2014-01-01

    Roč. 2014, č. 40 (2014), s. 88-98. ISSN 0142-9418 R&D Projects: GA ČR(CZ) GAP108/12/1560 Institutional support: RVO:68081723 Keywords : polypropylene * extruded polymer pipe * residual stress * curved beam methodology * numerical simulations Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.240, year: 2014 http://www.sciencedirect.com/science/article/pii/S0142941814001809

  13. Polypropylene matrix composites reinforced with coconut fibers

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

    2011-01-01

    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...

  14. Structural grafts and suture techniques in functional and aesthetic rhinoplasty

    Gassner, Holger G.

    2010-01-01

    Full Text Available Rhinoplasty has undergone important changes. With the advent of the open structure approach, requirements for structural grafting and direct manipulation of the cartilaginous skeleton through suture techniques have increased substantially. The present review analyzes the current literature on frequently referenced structural grafts and suture techniques. Individual techniques are described and their utility is discussed in light of available studies and data.

  15. Nose tip refinement using interdomal suture in caucasian nose

    Pasinato, Rogério

    2012-01-01

    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.

  16. High-resolution sonography of the abnormal cranial suture

    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.)

  17. High strain rate behaviour of polypropylene microfoams

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

    2012-08-01

    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.

  18. High strain rate behaviour of polypropylene microfoams

    Martínez A.B.

    2012-08-01

    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.

  19. The efficacy of a single continuous nylon suture for control of post keratoplasty astigmatism.

    Van Meter, W

    1996-01-01

    PURPOSE: Post operative adjustment of a single continuous suture is an effective means of reducing post keratoplasty astigmatism. This study evaluates post keratoplasty keratometry following suture adjustment with an adjusted suture in place and after the suture is removed. METHODS: Average keratometric astigmatism was measured over 24 months time in 26 patients with an adjusted continuous suture and 24 patients with a continuous suture that was not adjusted. Average keratometry in 43 patient...

  20. Radiation cross-linking of montmorillonite/polypropylene composite

    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 the composite in air. The effects of cross-linking agent and montmorillonite on 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-lining occurred in certain radiation dose range. The cross-linked polypropylene/montmorillonite composite exhibited improved mechanical properties. (authors)

  1. Performance of antegrade suture passers according to tendon thickness

    Myung-Sun Kim

    2015-01-01

    Full Text Available Purpose: To determine the effect of tendon thickness on the needle penetration ability of four different designs of antegrade suture passers. Materials and Methods: Four antegrade suture passers were tested: (a ExpresSew II (Depuy Mitek Inc., Raynham, MA, (b Arthrex Scorpion (Arthrex, Naples, FL, (c Concept (Linvatec Corp, Largo, FL, and (d ElitePass (Smith and Nephew Endoscopy, Andover, MA. Bovine tendons were divided into five thickness groups: 3, 5, 7, 9 and 11 mm. At each tendon thickness, we performed 15 trials with the suture loaded and 15 unloaded per device. Successful needle penetration was recorded, and in case of success, the exit point of the needle was noted in relation to the superior arm of the grasping component. Results: All tested suture passing devices successfully penetrated tendon thicknesses of 3 and 5 mm. With the suture loaded, one device (Concept only successfully penetrated 7 mm group tendons in 3/15 (20% trials. Success rates at 9 mm with the suture loaded were 40% in ExpresSew II, 53% in Arthrex Scorpion, 0% in Concept and 53% in ElitePass. Among successful passages with a loaded suture in the 7 and 9 mm-groups, about 20-50% of passages were oblique, and the needle came out distal to the superior arm of grasping the component. No trial with any device succeeded with 11 mm tendons in the suture loading condition. Conclusion: Using an antegrade suture passer during arthroscopic rotator cuff repair should be carefully considered when the torn end of the tendon is thicker than about 7-9 mm due to potential failure of needle penetration and/or too oblique a suture passage. Level of Evidence: Controlled laboratory study.

  2. Comparison of indium 111 oxine-labeled platelet aggregation between sutured and argon laser-assisted vascular anastomoses

    The thrombogenicity of argon laser-assisted vascular anastomoses (LAVAs) was compared with that of sutured vascular anastomoses (SVAs) by measurement of platelet aggregation at the site of repair in a canine model. Sequential 1 cm longitudinal carotid and femoral arteriotomies (n = 80) or jugular and femoral phlebotomies (n = 80) were performed, with each vessel having two tandem, randomly positioned arteriotomies or phlebotomies separated by a 4 cm length of intact vessel. One incision was repaired by SVA with continuous 6-0 polypropylene sutures and the other by argon LAVA. For the laser fusions, argon laser energy was applied to the adventitial surface of the vessel with a 300 micron fiberoptic probe with 0.5 W power, 1100 joules per square centimeter energy fluence, and 150 second exposure per 1 cm length. The arterial and venous segments of SVAs and LAVAs and an equivalent length of normal vessel were harvested at 48 hours (n = 16, 16, 16), 2 weeks (n = 12, 12, 12), and 4 weeks (n = 12, 12, 12). Autologous indium 111 oxine-labeled platelets were injected intravenously 48 hours before removal of the vascular repairs and the radioactivity of the specimens was determined on removal with a NaI (T1) well-type scintillation counter. Anastomotic platelet adherence index (APAI) was calculated as the ratio of emissions of SVA or LAVA to normal reference vessel

  3. Explosive spalling of concrete, the mitigating effect of Polypropylene Fibres

    Sørensen, Lars Schiøtt

    2003-01-01

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

  4. Fatigue mechanisms in unidirectional glass-fibre-reinforced polypropylene

    Gamstedt, E.K.; Berglund, L.A.; Peijs, T.

    1999-01-01

    Polypropylene (PP) and polypropylene modified with maleic anhydride (MA-PP) reinforced by continuous longitudinal glass fibres have been investigated. The most prominent effect of the modification with maleic anhydride in the composite is a stronger fibre/matrix interface. The effects of...

  5. THE FTIR STUDIES OF PHOTO-OXIDATIVE DEGRADATION OF POLYPROPYLENE

    WEN Zaiqing; HU Xingzhou; SHEN Deyan

    1988-01-01

    The photo-oxidative degradation process of polypropylene film containing iron ions was investigated via FTIR and absorbance substraction technique. It is shown that the iron ions play an important role in the decomposition of hydroperoxide and the increase of the degradation rate of polypropylene film. Theamorphous region of PP film undergoes degradation prior to the crystalline one.

  6. Midwives conducting perineal repair: The Danish Suture Trial

    Kindberg, Sara

    2007-01-01

    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 polyglactin 910 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...

  7. Structure development in melt processing isotactic polypropylene, polypropylene blends/compounds and dynamically vulcanized polyolefin TPEs

    Yu, Yishan

    The influence of various fillers, nucleating agents and ethylene propylene diene terpolymer (EPDM) additive on crystalline modification (alpha-, beta- and smectic forms) and crystalline orientation of polypropylene in die extrudates, melt spun filaments, thick rods, blow molded bottles and injection molded parts of isotactic polypropylene (PP), its blends/compounds and dynamically vulcanized polypropylene thermoplastic elastomers (TPEs) were experimentally studied under a range of cooling and processing conditions. The phenomena of crystallization, polymorphism and orientation in processing of both thin and thick samples (filaments, rods, bottles and injection molded parts) were simulated through transport laws incorporating polymer crystallization kinetics. Continuous cooling transformation (CCT) curves for the various material systems investigated were developed under quiescent and uniaxial stress conditions. We applied experimental data on polymorphism of thin sections to predict crystalline structure variation in thick parts. The predictions were consistent with experiments. For filaments, the polypropylene crystalline orientation-spinline stress relationship is generally similar for the neat PP, blends/compounds and TPEs. However, the blends and TPEs have much lower birefringence apparently due to a lack of orientation in the rubber phase. It was shown that the polypropylene contribution to the birefringence for the neat PP and its blends is the same at the same spinline stress. For bottles, the inflation pressures used have little effect on orientation of either polypropylene crystals or disc-shaped talc filler. The talc discs are highly oriented parallel to the bottle surface. For the bottles without talc, the orientation of polypropylene crystallographic axes are low. The polypropylene crystallographic b-axes in the talc filled bottles are more highly oriented. For injection molded parts, it was found that a low orientation layer exists between the part

  8. Viscoelastic properties of cellular polypropylene ferroelectrets

    Gaal, Mate; Bovtun, Viktor; Stark, Wolfgang; Erhard, Anton; Yakymenko, Yuriy; Kreutzbruck, Marc

    2016-03-01

    Viscoelastic properties of cellular polypropylene ferroelectrets (PP FEs) were studied at low frequencies (0.3-33 Hz) by dynamic mechanical analysis and at high frequencies (250 kHz) by laser Doppler vibrometry. Relaxation behavior of the in-plane Young's modulus ( Y11 ' ˜ 1500 MPa at room temperature) was observed and attributed to the viscoelastic response of polypropylene matrix. The out-of-plane Young's modulus is very small ( Y33 ' ≈ 0.1 MPa) at low frequencies, frequency- and stress-dependent, evidencing nonlinear viscoelastic response of PP FEs. The high-frequency mechanical response of PP FEs is shown to be linear viscoelastic with Y33 ' ≈ 0.8 MPa. It is described by thickness vibration mode and modeled as a damped harmonic oscillator with one degree of freedom. Frequency dependence of Y33 * in the large dynamic strain regime is described by the broad Cole-Cole relaxation with a mean frequency in kHz range attributed to the dynamics of the air flow between partially closed air-filled voids in PP FEs. Switching-off the relaxation contribution causes dynamic crossover from the nonlinear viscoelastic regime at low frequencies to the linear viscoelastic regime at high frequencies. In the small strain regime, contribution of the air flow seems to be insignificant and the power-law response, attributed to the mechanics of polypropylene cell walls and closed air voids, dominates in a broad frequency range. Mechanical relaxation caused by the air flow mechanism takes place in the sound and ultrasound frequency range (10 Hz-1 MHz) and, therefore, should be taken into account in ultrasonic applications of the PP FEs deal with strong exciting or receiving signals.

  9. MonoMax Suture: A New Long-Term Absorbable Monofilament Suture Made from Poly-4-Hydroxybutyrate

    Erich K. Odermatt

    2012-01-01

    Full Text Available A long-term absorbable monofilament suture was developed using poly-4-hydroxybutyrate (P4HB made from a biosynthetically produced homopolymer of the natural metabolite 4-hydroxybutyrate. The suture, called MonoMax, has prolonged strength retention. At 12 weeks, a size 3-0 MonoMax suture retains approximately 50% of its initial tensile strength in vivo and is substantially degraded in one year with minimal tissue reaction. In contrast, PDS II monofilament suture (Ethicon, Inc., Somerville, NJ has no residual strength in vivo after 12 weeks. In vivo, the MonoMax suture is hydrolyzed primarily by bulk hydrolysis, and is then degraded via the Krebs cycle. MonoMax is substantially more compliant than other monofilament sutures, and incorporates an element of elasticity. Its tensile modulus of 0.48 GPa is approximately one-third of the value of the PDS II fiber providing an exceptionally flexible and pliable fiber with excellent knot strength and security. These features are further enhanced by the fiber's elasticity, which also improves knot security and may help prevent wound dehiscence. Because of its performance advantages, this suture may find clinical utility in applications where prolonged strength retention, and greater flexibility are required, particularly in procedures like abdominal wall closure where wound dehiscence is still a significant post-surgical complication.

  10. Oxygen Permeability of Polypropylene Containing Polyisobutene with Magnesium Acetate

    2000-01-01

    The oxygen permeabilities of polypropylene films are reduced by adding a minor percentage of a polyisobutene ionomer. The polyisobutene ionomers were prepared by in situ salt exchange of magnesium acetate with maleated polyisobutenes of commercially available low relative molecular mass. The more polar magnesium salts aided phase separation during crystallization from the molten polypropylene mixture. Scanning electron microscope photographs revealed that the polyisobutene ionomer is largely concentrated in the amorphous regions between the polypropylene spherulites, where the ionomer tends to concentrate during crystallization. The influence of the polyisobutene ionomer on the oxygen permeability of polypropylene was found to be slightly dependent upon the relative molecular mass of the polyisobutene precursor. Under optimum conditions, the oxygen permeability of polypropylene is reduced by 20% with only 1% additive.

  11. RHEOLOGICAL BEHAVIOR OF KAOLIN TOUGHENED POLYPROPYLENE COMPOSITES

    OU Yuchun; FANG Xiaoping; FENG Yupeng

    1997-01-01

    The relation between the rheological behavior and various interfacial properties of Kaolin rigid particle toughened polypropylene(PP/Kaolin) composites were studied by means of parallel-plate rheometer, melt flow rate apparatus, scanning electron microscopy (SEM) and other testing methods. The results show that addition of interfacial modifier to PP/Kaolin composites is advantageous to homogeneous dispersion of filler in PP matrix,formation of flexible interlayer between Kaolin particles and PP matrix and improvement of the melt processibility of the composites.

  12. Improvement in the thermal performance of polypropylene

    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) γ-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 γ-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 γ radiation stability of iPP containing

  13. Cyclic viscoelastoplasticity of polypropylene/nanoclay composites

    Drozdov, A.; Christiansen, Jesper de Claville

    2012-01-01

    of nanofiller is demonstrated: reinforcement with 2 wt.% of clay results in strong reduction of maximum and minimum strains per cycle and growth of number of cycles to failure compared with neat polypropylene. To rationalize these findings, a constitutive model is developed in cyclic viscoelasticity...... and viscoplasticity of polymer nanocomposites. Adjustable parameters in the stress–strain relations are found by fitting experimental data. The model correctly describes the growth of the ratcheting strain and shows that fatigue failure is driven by a pronounced increase in plastic strain in the...

  14. 21 CFR 878.4930 - Suture retention device.

    2010-04-01

    ...) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4930 Suture retention device... premarket notification procedures in subpart E of part 807 of this chapter, subject to the limitations...

  15. A multiphase transitioning peptide hydrogel for suturing ultrasmall vessels.

    Smith, Daniel J; Brat, Gabriel A; Medina, Scott H; Tong, Dedi; Huang, Yong; Grahammer, Johanna; Furtmüller, Georg J; Oh, Byoung Chol; Nagy-Smith, Katelyn J; Walczak, Piotr; Brandacher, Gerald; Schneider, Joel P

    2016-01-01

    Many surgeries are complicated by the need to anastomose, or reconnect, micrometre-scale vessels. Although suturing remains the gold standard for anastomosing vessels, it is difficult to place sutures correctly through collapsed lumen, making the procedure prone to failure. Here, we report a multiphase transitioning peptide hydrogel that can be injected into the lumen of vessels to facilitate suturing. The peptide, which contains a photocaged glutamic acid, forms a solid-like gel in a syringe and can be shear-thin delivered to the lumen of collapsed vessels (where it distends the vessel) and the space between two vessels (where it is used to approximate the vessel ends). Suturing is performed directly through the gel. Light is used to initiate the final gel-sol phase transition that disrupts the hydrogel network, allowing the gel to be removed and blood flow to resume. This gel adds a new tool to the armamentarium for micro- and supermicrosurgical procedures. PMID:26524396

  16. Dynamic observation of biomechanic properties of sciatic nerve at the suture site in rats following repairing.

    Jiang, Baoguo; Zhang, Peixun; Yan, Jiazhi; Zhang, Hongbo

    2008-01-01

    To observe the biomechanic properties of the sciatic nerve at the suture site following repairing in rats. The right sciatic nerves of 40 white Sprague-Dawley 300~350 gm rats were exposed, cut and then repaired with 10-0 nylon sutures with four stitches, laced in the epineurium 0, 1, 3, and 6 weeks after operation, the tensile strength of the sciatic nerves were measured, and the data analyzed statistically. The load elongation curves for both the normal unoperated and operated nerves had similar shape. There were significant differences between the tensile strength of the 0th and the 1st, 3rd, and 6th weeks (P < 0.01). No significant difference was found among the 1st, 3rd, and 6th weeks. The tensile strength of the injured nerves recovered 48% of the normal nerve in the 1st week and 54% in 6 weeks after repairing. It may be concluded that the injured nerves can acquire mostly tensile strength stability in 1 week quickly and can maintain this relative tensile strength stability in 6 weeks. PMID:18293160

  17. SUTURE NON-SUTSRE CIRCUMFERENTIAL REPAIR OF CAROTID ARTERY

    Jafar Nader

    1969-01-01

    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

  18. Suture materials: composition and applications in veternary wound repair.

    Tan, R H H; Bell, R J W; Dowling, B A; Dart, A J

    2003-03-01

    Suture materials play an important role in veterinary surgery by providing support for healing tissues during wound repair. As there is no single ideal suture material, clinicians must compromise on some properties when selecting a material for a specific purpose. By reviewing the characteristics of absorbable and non-absorbable materials, general recommendations can be made on their usage in skin, fascia, viscera and other tissues. PMID:15080426

  19. Total laparoscopic hysterectomy via suture and ligation technique

    Kang, Hye Won; Lee, Ji Won; Ho Yeon KIM; Kim, Bo Wook; Moon, Chong Soo

    2016-01-01

    Objective The term 'total laparoscopic hysterectomy (TLH) with classical suture method' refers to a surgical procedure performed using only sutures and ligations with intracorporeal or extracorporeal ties, without using any laser or electronic cauterization devices during laparoscopic surgery as in total abdominal hysterectomy. However, the method is not as widely used as electric coagulation equipment for TLH because further advances in technology and surgical technique are required and oper...

  20. Experimental evaluation of horse hair as a nonabsorbable monofilament suture

    Swati R Yedke

    2013-01-01

    Full Text Available Background: Success of surgery depends on wound closure and healing. Ancients had coated many suture materials from plant and animal origin. As the quest for natural nonabsorbable, monofilament surgical suture continues, horsehair has been taken for study, which is mentioned in ancient literature. Objectives: Aim of the study was to evaluate detail mechanical and biophysical properties of horsehair. Materials and Methods: Physical properties, that are diameter, straight pull and knot pull tensile strength, bioburden, sterility tests were performed. Visual and histological wound healing parameters were studied in experimental Wistar rat incision wound model. Two experimental wounds about 5 cm long were created on each side of dorsal midline. Each animal received two sutures-Horsehair 4-0 and Ethilon 4-0. The sutured areas were grossly examined on 3 rd and 7 th days for visual observations like congestion, edema, infection, wound disruption, and impression of suture material on healed wound and then subjected for histological study. Results: Revealed that horsehair has got diameter of 0.19 mm which complies with the 4-0 size USP standard. Straight pull tensile strength was found 0.5851 ± 0.122 kg and knot pull tensile strength was 0.3998 ± 0.078 kg, which complies with the standards of United State Pharmacopia for class II nonabsorbable suture materials. In vivo study revealed that there was no evidence of edema, congestion, and discharge in both the groups. Wounds healed with minimum impressions of suture material with minimum scar mark. Mean histological scoring shows very mild tissue reaction. Conclusion: Horsehair has got properties of standard suture material except low tensile strength and hence can be used in reconstructive, plastic surgeries, and ophthalmic surgeries.

  1. Suturing technique for control of postkeratoplasty astigmatism and myopia.

    Dursun, Dilek; Forster, Richard K.; Feuer, William J.

    2002-01-01

    PURPOSE: We previously demonstrated that selective suture removal reduces keratoplasty astigmatism; however, a myopic shift was induced with increasing number of interrupted sutures removed. This study is an attempt to determine the effects of a modified surgical technique on postkeratoplasty myopia, astigmatism, and anisometropia. METHODS: Optical penetrating keratoplasties were performed on 92 eyes of 84 patients. The study group consisted of 92 consecutive penetrating keratoplasties perfor...

  2. Homology cylinders and sutured manifolds for homologically fibered knots

    Goda, Hiroshi; Sakasai, Takuya

    2008-01-01

    Sutured manifolds defined by Gabai are useful in the geometrical study of knots and 3-dimensional manifolds. On the other hand, homology cylinders are in an important position in the recent theory of homology cobordisms of surfaces and finite-type invariants. We study a relationship between them by focusing on sutured manifolds associated with a special class of knots which we call {\\it homologically fibered knots}. Then we use invariants of homology cylinders to give applications to...

  3. Colorectal polyp incidence among polypropylene manufacturing workers.

    Lewis, R J; Lerman, S E; Schnatter, A R; Hughes, J I; Vernon, S W

    1994-02-01

    To follow up earlier findings of increased colorectal cancer and polyp risk among a group of Texas polypropylene manufacturing workers, a second company-sponsored colorectal cancer screening program was conducted. Ninety-four (64%) of the 147 male workers negative for polyps in the first screening were rescreened. Age- and examiner-adjusted incidence rate ratios (IRRs) were modestly elevated for polypropylene manufacturing workers compared with patients screened at the same clinic for total (IRR = 1.31; 90% confidence interval [CI] = 0.84 to 2.03) and adenomatous (IRR = 1.80; 90% CI = 0.68 to 4.78) polyps. However, risk of adenomas among the highest exposed group (early term process/mechanical workers: IRR = 1.77; 90% CI = 0.51 to 6.18) was similar to risk in the least-exposed group (engineer/chemist/administrative workers: IRR = 2.02; 90% CI = 0.56 to 7.31). The modest, nonsignificant excesses and the similarity in risk across job categories does not suggest an occupationally related risk, although small numbers and potential biases preclude making definitive conclusions. PMID:8176517

  4. Improved oil spill recovery using polypropylene fabric

    An active boom for recovering oil spills was tested in a tank with diesel fuel, a motor oil, and a heavy crude oil. The boom consisted of a porous pipe wrapped in a polypropylene fabric to which a vacuum was applied. The diesel was recovered at a rate of 29 gal/h per ft2 of fabric surface area (GHPF) using a vacuum of 17 in. of water without any entrained water. The motor oil was recovered at a rate of 2.5 GHPF using a vacuum of 20 in. of water without any entrained water. The crude oil test at a vacuum of 8 in. Hg also resulted in a fluid recovery rate of 2.5 GHPF, but half of the recovered fluid was water. The results suggest that a device presenting a large surface area of polypropylene fabric to a spill of light or medium oil will separate the oil from the water. Uses for the device extend to other situations where oil-water separation is required. 1 ref., 4 figs., 3 tabs

  5. Development of braided drug-loaded nanofiber sutures

    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.

  6. The sutured Floer polytope and taut depth one foliations

    Altman, Irida

    2012-01-01

    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 ...

  7. Development of braided drug-loaded nanofiber sutures

    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

    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.

  8. Comparison of the cheese-wiring effects among three sutures used in rotator cuff repair

    Mark Lambrechts; Behrooz Nazari; Arash Dini; Michael J O′Brien; Heard, Wendell M. R.; Savoie, Felix H.; Zongbing You

    2014-01-01

    Purpose: The goal of this study was to compare the cheese-wiring effects of three sutures with different coefficients of friction. Materials and methods: Sixteen human cadaveric shoulders were dissected to expose the distal supraspinatus and infraspinatus muscle tendons. Three sutures were stitched through the tendons: #2 Orthocord™ suture (reference #223114, DePuy Mitek, Inc., Raynham, MA), #2 ETHIBONDFNx01 EXCEL Suture, and #2 FiberWire® suture (FiberWire® , Arthrex, Naples, FL). The su...

  9. Comparison of transosseous suture and suture anchors in the fixation of rotator cuff tears: a biomechanical experimental study

    Atalar, Ata Can; Demirhan, Mehmet; Bozdag, Ergun; Akalin, Yilmaz; Arpaci, Alaeddin

    2004-01-01

    Objectives: This study was designed to compare the primary fixation strength of transosseous sutures and suture anchors in rotator cuff repair. Methods: Thirty-two sheep shoulders were divided into four homogeneously equal groups. In each group, infraspinatus tendons were cut from their insertions and reattached with four diverse techniques, which included a single Mason-Allen stitch (group 1), double Mason-Allen stitches (group 2), double Mason-Allen stitches knotted on the lateral cortex...

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

    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.)

  11. Polypropylene and polycarbonate radiosterilization: effects on the stress resistance

    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

  12. Fatigue mechanisms in unidirectional glass-fibre-reinforced polypropylene

    Gamstedt, E.K.; Berglund, L.A.; Peijs, T.

    1999-01-01

    Polypropylene (PP) and polypropylene modified with maleic anhydride (MA-PP) reinforced by continuous longitudinal glass fibres have been investigated. The most prominent effect of the modification with maleic anhydride in the composite is a stronger fibre/matrix interface. The effects of...... about one decade for the composite with the stronger interface by use of the maleic-anhydride grafted polypropylene matrix. During the fatigue testing, the microscopic mechanisms were monitored intermittently by a surface replication technique. From microscopic observations, it could be concluded that...

  13. Determination of Partition Coefficients of Selected Model Migrants between Polyethylene and Polypropylene and Nanocomposite Polypropylene

    Pablo Otero-Pazos

    2016-01-01

    Full Text Available Studies on nanoparticles have focused the attention of the researchers because they can produce nanocomposites that exhibit unexpected hybrid properties. Polymeric materials are commonly used in food packaging, but from the standpoint of food safety, one of the main concerns on the use of these materials is the potential migration of low molecular substances from the packaging into the food. The key parameters of this phenomenon are the diffusion and partition coefficients. Studies on migration from food packaging with nanomaterials are very scarce. This study is focused on the determination of partition coefficients of different model migrants between the low-density polyethylene (LDPE and polypropylene (PP and between LDPE and nanocomposite polypropylene (naPP. The results show that the incorporation of nanoparticles in polypropylene increases the mass transport of model migrants from LDPE to naPP. This quantity of migrants absorbed into PP and naPP depends partially on the nature of the polymer and slightly on the chemical features of the migrant. Relation (RPP/naPP between partition coefficient KLDPE/PP and partition coefficient KLDPE/naPP at 60°C and 80°C shows that only BHT at 60°C has a RPP/naPP less than 1. On the other hand, bisphenol A has the highest RPP/naPP with approximately 50 times more.

  14. Disposable circumcision suture device:clinical effect and patient satisfaction

    BoDong Lv; ShiGeng Zhang; XuanWen Zhu; Jie Zhang; Gang Chen; MinFu Chen; HongLiang Shen; ZaiJun Pei; ZhaoDian Chen

    2014-01-01

    In our experience patients undergoing circumcision are mostly concerned about pain and penile appearances. We conducted a prospective randomized trial to assess the beneifts 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 signiifcantly lower in the Shang ring and suture device groups compared to the conventional group (P<0.001). Intra-operative pain was less in the suture device group compared with the other two groups (P<0.001);whereas post-operative pain was higher in the conventional group compared to the other two groups (P<0.001). Patients in the suture device (80.57%) and Shang ring (73.57%) groups were more satisifed with penile appearances compared with the conventional circumcision group (20.06%, P<0.05). Patients in suture device group also healed markedly faster than the conventional group (P<0.01). The overall satisfaction rate was better in the suture device group (78.66%) compared with the conventional (47.13%) and Shang ring (50.00%) groups (P<0.05). The combination of DCSD and lidocaine cream resulted in shorter operation and incision healing times, reduced intra-operative and post-operative pain and improved patient satisfaction with the cosmetic appearances.

  15. Diminished suture strength after robotic needle driver manipulation.

    Ricchiuti, Daniel; Cerone, Jeffrey; Shie, Scott; Jetley, Ajay; Noe, Donald; Kovacik, Mark

    2010-09-01

    Robot-assisted minimally invasive surgery has become a routine surgical option for the treatment of prostate cancer. Despite its technical advancements, the da Vinci(®) Surgical System still lacks haptic feedback to the surgeon, resulting in a maximally applied compressive force by the robotic needle driver during every grasping maneuver. Without this perceptional sense of touch and grip control, repetitive robotic needle driver manipulation may unknowingly lead to irreparable damage to fine sutures used during delicate anastomotic repairs. For robotic prostatectomy, any such loss of integrity can potentially lead to premature breakdown of the urethrovesical anastomosis and urine extravasation, especially important for a less-than-perfectly fashioned anastomotic repair. Although it has already been established that overhandling of sutures using handheld laparoscopic instruments can lead to reduced suture strength, it has not been established to what extent this may occur after robotic surgical procedures. We present analytical data and analyses concerning the failure strength of fine sutures commonly used for urethrovesical anastomotic repair during robotic prostatectomy, after repetitive robotic needle driver manipulation. When compared with noncompromised monofilament suture controls, the average maximal failure force after repetitive robotic manipulation was significantly reduced by 35% (p < 0.0001). Similarly, the average maximal failure force of braided sutures was significantly reduced after repetitive robotic manipulation by 3% (p = 0.009). This work demonstrates that significant reductions in monofilament and braided suture strength integrity can occur after customary repetitive manipulation by robotic needle drivers in an ex vivo model, with further research warranted in the in vivo setting. PMID:20653422

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

    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.

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

    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

    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.

  18. Mechanical Properties of Nanofilled Polypropylene Composites

    Cristina-Elisabeta PELIN

    2015-06-01

    Full Text Available The paper presents a study concerning mechanical performance of thermoplastic nanocomposites based on isotactic polypropylene matrix, nanofilled with montmorillonite modified with quaternary ammonium salt and carboxyl functionalized carbon nanotubes, respectively, added in the same concentration relative to the matrix. The nanofilled and single polymer materials were obtained by simple melt compounding through extrusion process followed by injection molding into specific shape specimens for mechanical testing of the samples. Mechanical properties were evaluated by tensile and 3 point bending tests. In terms of modulus of elasticity, the results showed overall positive effects concerning the effect of nanofiller addition to the thermoplastic polymer. The fracture cross section of the tested specimens was characterized by FT-IR spectroscopy and SEM microscopy.

  19. Anisotropic thermal conductivity in sheared polypropylene

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

    2006-01-01

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

  20. Radiation cross-linking of montmorillonite/polypropylene composite

    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)

  1. Recognizing surgeon's actions during suture operations from video sequences

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

    2014-03-01

    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.

  2. Study on the Dynamic Performance of Polypropylene Fiber Reinforced Concrete

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

    2013-01-01

    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...

  3. Preparation of Polypropylene/Montmorillonite Nanocomposites Using Ionizing Radiation

    Polymer/clay nanocomposites are new generation materials that bring significant changes in mechanical, thermal and permeation properties of base polymers by low clay loading. In this study, polypropylene/montmorillonite nanocomposites were prepared by melt intercalation method by using batch type mixer. Two polypropylene samples with different melt flow indexes are used as the matrix, maleic anhydride grafted polypropylene (PP-g-MAH), and polypropylene granules oxidized by radiation/ozone are used as compatibilizer and unmodified clay (Na+ montmorillonite, MMT) as the filler. Aim of this study is to examine the effect of different compatibilizers in the mechanical properties of polypropylene composite. Firstly, PP/clay samples were prepared and the effect of clay was examined, then 5, 10, 20kGy oxidized/degraded polypropylenes were used as compatibilizer and, 10 kGy was determined to be the most suitable irradiation dose for the best compatibilizing effect. Polypropylene granules were ozonated until they contained carbonyl groups equivalent to 10kGy oxidized PP, which was checked by FTIR-ATR spectroscopy. UV-visible reflectance measurements were also made on film samples and no significant changes were observed in visible region. Nano structures of some nanocomposites were characterized by PALS (Positron Annihilation Lifetime Spectroscopy) where it was observed that the addition of clay decreased the number of free volume holes and free volume hole radia. The dispersion state of MMT within polymer matrix was analyzed by XRD (X-ray diffraction). Tensile tests were made and the effect of the addition of clay and compatibilizers investigated. At low melt flow index PP, 1% MMT of PP/10kGyPP/MMT nanocomposite showed an increase in E-modulus 26% and in tensile strength 8% as compared to those of pristine PP. In conclusion radiation degraded (chain scissioned and oxidized) PP has been found to show very good compatibilizing effect for the natural montmorillonite/polypropylene

  4. Application of gas chromatography to the investigations on polypropylene radiolysis

    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

  5. Surface and mechanical properties of polypropylene/clay nanocomposite

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

    2013-01-01

    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...

  6. Polypropylene/graphite nanocomposites by in situ polymerization

    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)

  7. Radiation resistant modified polypropylene; Polipropylen modyfikowany odporny radiacyjnie

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

    1997-10-01

    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.

  8. Ethibond suture in uterus: an unusual cause for secondary sterility

    Rajendra kumar Diwakar

    2015-12-01

    Full Text Available Failure to conceive two years after the LSCS, the patient was being investigated. Hysteroscopy revealed the presence of Ethibond suture in the uterine cavity attached to the lower part of the previous LSCS scar. The presence of this foreign body was acting as an intra-uterine contraceptive device responsible for failure of contraception. The presence of foreign body in the uterus such as bone pieces left after previous abortion, presence of suture of cervical circlage etc. have been reported. But the presence of Ethibond suture in the uterine cavity resulting in secondary sterility is being reported for the first time. [Int J Reprod Contracept Obstet Gynecol 2015; 4(6.000: 2050-2052

  9. EVALUATION OF ADJUSTABLE SUTURE TECHNIQUE IN OUTCOME OF PTOSIS SURGERY

    Nagaraju

    2015-10-01

    Full Text Available AIM: To evaluate the outcome of adjustable suture technique in ptosis surgery. INTRODUCTION : Surgical management of blepharoptosis is indicated in multiple situations and the post - operative outcomes can be as variable as the indications for surgery. Adjustable suture techniques in ptosis repair have been introduced and variable efficacies have been reported. MATERIALS AND METHODS: A retrospective case review of medical records from June 2010 to May 2011 (12 months of 5 eyes of 5 consecutive patients operated by a single surgeon at a Tertiary Eye care center in South India were reviewed. The clinical profile of patients included was r ecorded and results of adjustable suture technique described by Borman and collegues for these patients was reported. RESULTS: 5 eyes of 5 patients underwent adjustable suture ptosis repair in the study duration. 4 patients with moderate and 1 with severe ptosis, all having good levator function were diagnosed to have c ongenital ptosis in 3 cases and a cquired involutional ptosis in 2 cases. All 5 cases had a satisfactory outcome at day 4 post - operative after adjustment of lid height in the out - patient clini c. 1 patient with acquired involutional ptosis, identified with levator dehiscence intra - operatively had overcorrection at 6 months warranting re - surgery while the other 4 patients had satisfactory cosmetic lid height and functional outcome at 6 months fol low up after the adjustable suture technique for ptosis repair. CONCLUSION: Use of adjustable sutures in ptosis surgery can eliminate the intraoperative lid factors that can lead to unpredictable results. The technique described is easy to adapt and perfor m and can give repeatable and well acceptable results in the properly selected cases

  10. Familial idiopathic hypertrophic osteoarthropathy and cranial suture defects in children

    Three children with idiopathic hypertrophic osteoarthropathy and cranial suture defects are reported. The syndrome was recognized after birth and in the two oldest siblings, the cranial defects and subperiosteal bone formation resolved almost completely by age 4 and 6 years. The joint swelling and clubbing persisted and mild bone reabsorption of the distal phalanges became apparent at an older age. Two siblings and both parents had normal bone X-rays and no clubbing. This study confirms the association of cranial sutural defects and familial idopathic hypertrophic osteoarthropathy. (orig.)

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

    Elif Sarı

    2014-12-01

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

  12. Flow-induced crystallization in isotactic polypropylene

    Hamad, Fawzi Ghassan

    Brief intervals of strong flow stretch chains in a semicrystalline polymer melt, which results in an increase in the nuclei number density and a transformation of the crystal structure. This flow-induced crystallization (FIC) phenomenon is explored in this study using highly isotactic polypropylene (iPP) samples. Using one synthesized and five commercial linear isotactic polypropylene samples, we investigate the FIC behavior by imposing shear onto these samples in a rotational rheometer. Equipped with a good temperature control and flexible shear protocol, we apply different temperature and flow conditions. The magnitude of the FIC effect varies with basic processing parameters (shear rate, specific work, crystallization temperature, and shearing temperature) and material properties (totalistic, molecular weight distribution, and particle concentration in the polymer). The scope of this study is to systematically investigate the influences of these parameters on FIC. The FIC effects that are investigated in this dissertation are: crystallization kinetics, persistence time of flow-induced nuclei, and crystal morphology. The crystallization time was measured in the rheometer by monitoring the onset of crystallization after quenching samples sheared above Tm. These samples were subsequently used to study their flow-induced nuclei persistence time and crystal morphology. The lifetime of flow-induced nuclei was determined by measuring the time required to return from FIC back to quiescent crystallization using a differential scanning calorimeter. The crystal morphology was imaged using polarized optical microscopy and atomic force microscopy. We investigated the influence of specific work on the three FIC characteristics, and found three regimes that are separated by the critical work ( Wc) and the saturation work (Wsat) thresholds. Below the critical work threshold, the morphology is composed of mostly spherulite crystals, which keep a constant volume, and a small

  13. Magnetic fluids stabilized by polypropylene glycol

    Lebedev, A.V., E-mail: lav@icmm.r [Institute of Continuous Media Mechanics, UB RAS, Academic Korolev Str. 1, Perm 614013 (Russian Federation); Lysenko, S.N. [Institute of Technical Chemistry, UB RAS, Academic Korolev Str. 3, Perm 614013 (Russian Federation)

    2011-05-15

    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 {sup o}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. - Research highlights: PPG stabilizes the magnetic particles in the polar and non-polar media. The minimum operating temperature reaches -115 {sup o}C. Alcohols are the best environment for PPG-stabilized particles. PPG magnetic fluids can be used as magnetic extractors of alcohol. PPG MF can be divided into fractions by partial coagulation with water.

  14. Polypropylene matrix composites reinforced with coconut fibers

    Maria Virginia Gelfuso

    2011-09-01

    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 (σ~28 MPa compared to the untreated fibers composite (σ~22 MPa or alkali treatment (σ~24 MPa. However, CMUV composites containing 10 vol. (% fiber presented best results for the electrical tracking test and electrical resistivity (3 × 10(7 Ω.m. The results suggest that composites reinforced with mechanically treated coconut fibers are suitable for electrical applications.

  15. On Crystallization in Polypropylene-Polyethylene Blends

    2001-01-01

    Blends of polypropylene(PP) and low-density polyethylene (LDPE) have beencrystallized to form open structures(“cluster spherulites”) where the droplets of the minorityPP are bridged by PP lamellae which have grown in the LDPE-rich matrix. These are studiedby permanganic etching followed by electron and optical microscopies. Two similar PP typesare compared, one synthesized with Ziegler-Natta catalyst and one with metallocenecatalyst. The metallocene-catalysed material crystallized much more slowly due to thepresence of regio defects in the chains, even though the overall concentration of tacticitydefects in the Ziegler-Natta material is much higher. A mechanism involving reversal ofhelical direction at the regio defect interfering with the regular chain packing in the crystal issuggested. Growth of “cluster spherulites” is faster in regions where low molecular weightmaterial is concentrated. It is slower where droplets are larger, and this is attributed tocompetition between PP lamellar growth in the matrix and diffusion of PP to alreadycrystallized droplets.

  16. Surface modification of polypropylene based particle foams

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

    2014-05-01

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

  17. Electrical properties of ion irradiated polypropylene films

    N L Singh; Anita Sharma; V Shrinet; A K Rakshit; D K Avasthi

    2004-06-01

    The effect of high-energy (50 MeV) Li3+ ion beam irradiation on polypropylene (PP) film has been studied in the fluence range 2.4 × 1012-1.5 × 1014 ions/cm2. The a.c. electrical properties of PP films were measured in the frequency range from 0.05–100 kHz, and at temperature range between 30 and 140°C. This study indicates two peaks at 60°C and 120°C with comparatively high magnitudes. There is an exponential increase in conductivity with log of frequency and the effect is significant at higher fluences. The loss factor (tan ) vs frequency plot suggests that PP film based capacitors may be useful below 10 kHz. The capacitance is constant over a wide temperature range up to 130°C. FTIR spectra of the PP films before and after irradiation indicate that intensity of C–H stretching vibration at 2900 cm-1 is modified. The presence of many new peaks with the increase of fluence suggests the formation of alkanes and alkynes which might be responsible for the observed changes in the dielectric and electrical properties of PP films.

  18. Microwave Irradiation on Halloysite-Polypropylene Nanocomposites

    Espino, Omar; Yust, Brian; Chipara, Dorina; Ajayan, Pullickel; Chipara, Alin; Chipara, Mircea; Utrgv Collaboration; Rice Collaboration

    Halloysite is an unique cyllindrical nanoclay characterized by poor electrical and thermal conductivity, which may become the filler of choice for the reinforcement of polymeric matrix, where electrical or thermal insulation are required. The main limits in the use of halloysite as replacement for carbon nanotube (CNT) are: 1. Smaller aspect ratio as halloysites are typically shorter than CNTs. 2. Smaller Young modulus of halloysites compared with CNTs. 3. Reduced thermal stability due to the loss of water upon heating. A research on halloysite dispersed within isotactic polypropylene is reported. To improve the interface between the halloysite and the polymeric matrix a microwave irradiation step has been considered. The local heating of the halloysite nanotubes is mediated by the absorbed/structural water content of the nanoclay. Nanocomposites loaded by various amounts of halloysite ranging from 0 % to 20 % wt. have been prepared by melt mixing by using a Haake RheoMixer. The as obtained nanocomposites have been subjected to microwave irradiation at 75 W in an Anton Paar Monowave 300 system and various irradiation times ranging from 5, 10, 15, 30, 45, and 60 minutes. The effect of microwave irradiation has been studied by Raman and FTIR spectroscopy

  19. Optical Properties of Polypropylene upon Recycling

    Felice De Santis

    2013-01-01

    Full Text Available In the last few years there has been an increasing interest in the possibility of recycling polymeric materials, using physical recycling. However, is it well known that polymers experience a depletion of all the properties upon recycling. These effects have been widely characterized in the literature for what concerns the mechanical or rheological properties. The changes of optical properties after recycling have been much less studied, even if, especially in food packaging, optical characteristics (above all the opacity are of extreme importance, and thus it is quite significant to assess the effect of recycling on these properties. In this work, the influence of recycling steps on the opacity of films of a commercial grade of isotactic polypropylene (i-PP was studied. The material was extruded several times to mimic the effect of recycling procedures. After extrusion, films were obtained by cooling samples of material at different cooling rates. The opacity of the obtained films was then measured and related to their crystallinity and morphology. It was found that opacity generally increases on increasing the amount of α phase and for the same amount of α phase on increasing the size of the spherulites.

  20. Biomechanical trial of modified flexor tendon sutures: an in vitro study.

    Vlajcic, Zlatko; Zic, Rado; Skenderi, Zenun; Bilic-Zulle, Lidija; Martic, Kresimir; Stanec, Zdenko

    2012-09-01

    Proven benefits of early active mobilisation for intra-synovial flexor tendon repairs have inducted new criteria for a 'perfect suture'. This study has examined different variations of modified Kessler's suture, which could fulfil the new criteria. A total of 93 swine extensor tendons were transected, repaired and tested using a dynamometer with constant rate of extension. The first part of study tested clinically the most used modified Kessler suture, a variation of double modified Kessler suture and intact tendons as a control group. Further variations in the second part of study were due to type of suture, location and number of the knots and type of peripheral suture. According to the results, the tested version of double modified Kessler suture with crossed peripheral suture was the strongest one among all tested variations. The ultimate force for the authors preferred modification of the double modified Kessler (DMK) is significantly higher than modified Kessler suture. The version of DMK with crossed peripheral suture is the strongest one among all tested variations. The lowest strength manifests variation with two knots between tendon ends. The variations with interlocked and outsided knot or monofilament tread are not statistically significant regarding ultimate force. The frequency of suture failure events (suture pull out or tendon and/or suture rupture) is equal respecting braided or monofilament suture. The preferred modification of the double modified Kessler (DMK) suture with crossed peripheral suture is the strongest one among all tested variations and could achieve, concerning range of force, early active mobilisation. Further variations due to the type of thread and location, type and number of the knots did not show statistical significance. PMID:22784225

  1. Comparison between Silk Sutures and Cyanoacrylate Adhesive in Human Mucosa- A Clinical and Histological Study

    Kumar, M Suresh; Natta, Sreelakshmi; Shankar, Gowri; Reddy, S Hari Krishna; Visalakshi, D; Seshiah, G V

    2013-01-01

    Background: Closing the surgical incision is an important step in the surgical procedures, the success of surgery is sometimes compromised by the defective suturing techniques or improper suturing materials, black silk sutures are more or less most often used materials in the day today surgical procedures, but these suture materials demand more time and effort from the surgeon and there is a need to substitute these materials with more user friendly and more successful wound closing materials...

  2. Comparison of the cheese-wiring effects among three sutures used in rotator cuff repair

    Mark Lambrechts

    2014-01-01

    Full Text Available Purpose: The goal of this study was to compare the cheese-wiring effects of three sutures with different coefficients of friction. Materials and methods: Sixteen human cadaveric shoulders were dissected to expose the distal supraspinatus and infraspinatus muscle tendons. Three sutures were stitched through the tendons: #2 Orthocord™ suture (reference #223114, DePuy Mitek, Inc., Raynham, MA, #2 ETHIBONDFNx01 EXCEL Suture, and #2 FiberWire® suture (FiberWire® , Arthrex, Naples, FL. The sutures were pulled by cyclic axial forces from 10 to 70 N at 1 Hz for 1000 cycles through a MTS machine. The cut-through distance on the tendon was measured with a digital caliper. Results: The cut-through distance in the supraspinatus tendons (mean ± standard deviation, n = 12 were 2.9 ± 0.6 mm for #2 Orthocord™ suture, 3.2 ± 1.2 mm for #2 ETHIBONDFNx01 suture, and 4.2 ± 1.7 mm for #2 FiberWire® suture. The differences were statistically significant analyzing with analysis of variance (P = 0.047 and two-tailed Student′s t-test, which showed significance between Orthocord™ and FiberWire® sutures (P = 0.026, but not significant between Orthocord™ and ETHIBONDFNx01 sutures (P = 0.607 or between ETHIBONDFNx01 and FiberWire® sutures (P = 0.103. Conclusion: The cheese-wiring effect is less in the Orthocord™ suture than in the FiberWire® suture in human cadaveric supraspinatus tendons. Clinical Relevance: Identification of sutures that cause high levels of tendon cheese-wiring after rotator cuff repair can lead to better suture selection.

  3. An absorbable thread suture technique to treat snoring.

    Kwon, Jang-Woo; Kong, Tae-Hoon; Ha, Tae-Hyoung; Park, Dong-Joon

    2016-05-01

    We investigated a novel, minimally invasive surgery that uses an absorbable suture technique to treat snoring and mild obstructive sleep apnea. This simple procedure was developed to increase the stiffness of the soft palate and to promote uvula elevation with sutures. Thirty-five snorer and mild obstructive sleep apnea syndrome patients were included in this study. The palate was sutured with the newly developed technique. The results of our surgery were evaluated using polysomnography (PSG), the Epworth sleepiness scale (ESS), and a visual analogue scale (VAS) before surgery and 90 days after surgery. One year after surgery, telephone interviews were performed to assess patient satisfaction. Postoperative physical examinations of all patients showed increased stiffness of the soft palate and superiorly displaced uvula. These findings were consistent after the postoperative day 90. The patients' snoring symptoms and their bed partners' complaints, assessed by ESS and VAS, significantly improved compared to the pre-treatment value (p PSG, was significantly improved compared to the pre-treatment value (p < 0.05). Based on the results from the telephone interviews analyzed 1 year after surgery, about 88 % of patients were satisfied with the outcome. This minimally invasive snoreplasty that uses absorbable suture material is an effective and simple procedure for treating snoring and mild obstructive sleep apnea. PMID:26162452

  4. Healing of the suture line in the irradiated small intestine

    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

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

    Microspheres assembled from carbon nanotubes (MCNTs), with the diameters ranging from 5.5 to 7.5 μm, 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.

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

    P.S.M. Megat-Yusoff

    2013-01-01

    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.

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

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

    2012-01-15

    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.

  8. Cosmetic outcome and surgical site infection rates of antibacterial absorbable (Polyglactin 910) suture compared to Chinese silk suture in breast cancer surgery: a randomized pilot research

    ZHANG Zhong-tao; Jessica Shen; Martin Weisberg; ZHANG Hong-wei; FANG Xue-dong; WANG Li-ming; LI Xiao-xi; LI Ya-fen; SUN Xiao-wei; Judith Carver; Dorella Simpkins

    2011-01-01

    Background The primary objective of this multicenter post-market study was to compare the cosmetic outcome of triclosan-coated VICRYL* Plus sutures with Chinese silk sutures for skin closure of modified radical mastectomy. A secondary objective was to assess the incidence of surgical site infection (SSI).Methods Patients undergoing modified radical mastectomy were randomly assigned to coated VICRYL* Plus antibacterial (Polyglactin 910) suture or Chinese silk suture. Cosmetic outcomes were evaluated postoperatively at days 12 (±2) and 30 (±5), and the evidence of SSI was assessed at days 3, 5, 7, 12 (±2), 30 (±5), and 90 (±7). Cosmetic outcomes were independently assessed via visual analogue scale (VAS) score evaluations of blinded incision photographs (primary endpoint) and surgeon-assessed modified Hollander Scale (mHCS) scores (secondary endpoint).SSI assessments used both CDC criteria and ASEPSIS scores.Results Six Chinese hospitals randomized 101 women undergoing modified radical mastectomy to closure with coated VICRYL* Plus suture (n=51) or Chinese silk suture (n=50). Mean VAS cosmetic outcome scores for antibacterial suture (67.2) were better than for Chinese silk (45.4) at day 30 (P<0.0001)). Mean mHCS cosmetic outcome total scores, were also higher for antibacterial suture (5.7) than for Chinese silk (5.0) at day 30 (P=0.002).Conclusions Patients using coated VICRYL* Plus suture had significantly better cosmetic outcomes than those with Chinese silk sutures. Patients using coated VICRYL* Plus suture had a lower SSI incidence compared to the Chinese silk sutures, although the difference did not reach statistical significance. (ClinicalTrials.gov NCT 00768222)

  9. Gamma radiation resistance of tale-polypropylene composite materials

    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

  10. Graft-copolymerization of hydrophilic monomers onto irradiated polypropylene fibers

    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

  11. Flexural Fatigue Behavior of Polypropylene Fiber Reinforeed Segment Conerete

    2006-01-01

    The influence of polypropylene fiber on the flexural fatigue performance of high- strength concrete (HSC), which could be used as cover of reinforcement of segment, was investigate by three-point load bending tests. Also, the flexural fatigue equations of high-strength concrete with and without polypropylene fiber were established through test analysis. The experimental results indicate that the addition of polypropylene fiber can improve the static bending strength of segment concrete, and the important is that it can markedly increase the flexural fatigue performance of the HSC subjected to cyclic bending load. Especially when with 1.37 kg/m3 addition of the fiber was corporate with silica fume and slag powder, the fatigue life of the HSC can be increased by 43.4% compared to that of the segment concrete without fiber,silica fume and slag.

  12. Surface and mechanical properties of polypropylene/clay nanocomposite

    Dibaei Asl Husein

    2013-01-01

    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.

  13. Silicon oxide diffusion barrier coatings on polypropylene

    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.

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

    F Maldonado

    2006-01-01

    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

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

    Morris C Phillip

    2007-12-01

    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

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

    Stephen H Cummings

    2012-07-01

    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

  17. Grafting polymerization of styrene onto preirradiated polypropylene fabric

    Grafting copolymerization of styrene onto polypropylene fabric has been studied by using a gamma ray preirradiation technique. The polypropylene fabric samples were irradiated in an environment of air and nitrogen gas. The effects of the absorbed dose, styrene concentration in methanol, reaction temperature and reaction time on the degree of grafting were determined. The effects of a polyfunctional monomer and sulphuric acid on the grafting yield were also examined. The samples irradiated in nitrogen gas gave a much higher degree of grafting than those in air. The addition of sulfuric acid and polyfunctional monomer in the grafting solution enhanced greatly the grafting yield

  18. Production of the oxidation-resistant polypropylene track membranes

    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 μm 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

  19. Reinforcement of Recycled Foamed Asphalt Using Short Polypropylene Fibers

    Yongjoo Kim; Tae-Soon Park

    2013-01-01

    This paper presents the reinforcing effects of the inclusion of short polypropylene fibers on recycled foamed asphalt (RFA) mixture. Short polypropylene fibers of 10 mm length with a 0.15% by weight mixing ratio of the fiber to the asphalt binder were used. The Marshall stability test, the indirect tensile strength test, the resilient modulus test, and wheel tracking test of the RFA mixtures were conducted. The test results were compared to find out the reinforcing effects of the inclusion of...

  20. Investigation into effects of environmental radiation on polypropylene bags

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

  1. Properties of antibacterial polypropylene/nanometal composite fibers.

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

    2012-01-01

    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

  2. Shrinkage of polypropylene fibre reinforced high strength concrete

    Zajec, Matija

    2012-01-01

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

  3. Estrogen/estrogen receptor alpha signaling in mouse posterofrontal cranial suture fusion.

    Aaron W James

    Full Text Available BACKGROUND: While premature suture fusion, or craniosynostosis, is a relatively common condition, the cause is often unknown. Estrogens are associated with growth plate fusion of endochondral bones. In the following study, we explore the previously unknown significance of estrogen/estrogen receptor signaling in cranial suture biology. METHODOLOGY/PRINCIPAL FINDINGS: Firstly, estrogen receptor (ER expression was examined in physiologically fusing (posterofrontal and patent (sagittal mouse cranial sutures by quantitative RT-PCR. Next, the cranial suture phenotype of ER alpha and ER beta knockout (alphaERKO, betaERKO mice was studied. Subsequently, mouse suture-derived mesenchymal cells (SMCs were isolated; the effects of 17-beta estradiol or the estrogen antagonist Fulvestrant on gene expression, osteogenic and chondrogenic differentiation were examined in vitro. Finally, in vivo experiments were performed in which Fulvestrant was administered subcutaneously to the mouse calvaria. Results showed that increased ERalpha but not ERbeta transcript abundance temporally coincided with posterofrontal suture fusion. The alphaERKO but not betaERKO mouse exhibited delayed posterofrontal suture fusion. In vitro, addition of 17-beta estradiol enhanced both osteogenic and chondrogenic differentiation in suture-derived mesenchymal cells, effects reversible by Fulvestrant. Finally, in vivo application of Fulvestrant significantly diminished calvarial osteogenesis, inhibiting suture fusion. CONCLUSIONS/SIGNIFICANCE: Estrogen signaling through ERalpha but not ERbeta is associated with and necessary for normal mouse posterofrontal suture fusion. In vitro studies suggest that estrogens may play a role in osteoblast and/or chondrocyte differentiation within the cranial suture complex.

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

    Fernandes MA

    2014-02-01

    Full Text Available Marcos AP Fernandes,1 Bruno MT Pereira,2 Sandra M Guimarães,1 Aline Paganelli,3 Carlos Manoel CT Pereira,1 Claudio Sergio Batista4 1Institute of Obesity and Advanced Video Laparoscopic Surgery of Petropolis, Rio de Janeiro, Brazil; 2Division of Trauma, University of Campinas, São Paulo, Brazil; 3Laboratório de Patologia Micron Cell Diagnóstico, Rio de Janeiro, Brazil; 4Department of Gynecology and Obstetrics, Faculty of Medicine of Petropolis, Rio de Janeiro, Brazil Context and objective: Variations in the ability of surgeons served as motivation for the development of devices that, overcoming individual differences, allow the techniques to be properly performed, and of which the end result was the best possible. Every technique must be reproduced reliably by the majority of surgeons for their results to be adopted and recognized as effective. The aim of this study was to compare the results, from the point of view of anatomic pathology, of manual sutures versus mechanical sutures using different models of linear mechanical staplers, in the procedure of gastroenteroanastomosis and enteroanastomosis in swine. Methods: Thirty-six healthy, adult, male Sus scrofa domesticus pigs, weighing between 20.7 and 25.5 kg, were used. The swine were randomly divided into four groups of nine pigs, according to the type of suture employed: group A, manual suture with Polysorb® 3-0 wire; group B, 80-shear linear stapler (Covidien® Gia 8038-S; group C, 75-shear linear stapler (Ethicon® Tlc 75; and group D, 75-shear linear stapler (Resource® Yq 75-3. A temporal study was established on the seventh postoperative day for histopathological analysis, and the degree of inflammation, fibrosis, and newly formed vessels, as well as the presence or absence of granulation tissue, foreign body granuloma, and necrosis were all evaluated qualitatively and semiquantitatively. The results were analyzed statistically. Results: Observations during the histopathological

  5. Dynamic Observation on the Effects of Different Suture Techniques on the Biomechanical Properties in the Healing of Tendons

    2005-01-01

    To identify the best suture techniques for the tendon repair, the biomechanical properties of tendons sutured by different methods were dynamically examined. 140 chickens were divided into 2 groups equally: group A and group B. The tendon of the right side was subjected to injury-repair process, and the tendons of the left sides served as controls in both groups. In group A, "figure-of8" suture, modified Kessler suture and Bunnell suture were used for the 2nd to 4th paws respectively, while in group B, Kleinert suture, Tsuge suture and Ikuta suture were used. On the day 0, 3,7, 14, 21, 28, 42 after operation, 10 animals were sacrificed and the flexor tendons of both sides were harvested for strength test. The results showed that the initial strength of the repaired tendons and the strength after 6 weeks following tendon cut were far below those of intact tendons, irrespective of suture techniques used. With the 6 techniques, the Pmax of tendons repaired by Tsuge suture was increased continually, reaching the highest value on the 42nd day. The Pmax of tendons sutured by the modified Kessler suture was slightly lower than that by Tsuge suture, but it was increased steadily in healing. The tendons repaired by figure-of-8 suture yielded the lowest Pmax. It was concluded that Tsuge suture and modified Kessler suture were the best techniques for tendon repair.

  6. Perioperative Modulating Factors on Astigmatism in Sutured Cataract Surgery

    Cho, Yang Kyeung; Kim, Man Soo

    2009-01-01

    Purpose To evaluate the factors that affect postoperative astigmatism and post-suture removal astigmatism, and to evaluate the risk factors associated with astigmatism axis shift. Methods We performed a retrospective chart review of 130 eyes that had undergone uneventful phacoemulsification cataract surgery. Preoperative astigmatism was divided into four groups (Groups I, II, III, and IV) according to the differences between the axis of preoperative astigmatism (flattest axis) and the incisio...

  7. Suturing of digital lacerations: digital block or local infiltration?

    Evans, David M.

    1991-01-01

    A prospective trial was carried out to assess the relative efficiency of digital block and local infiltration as methods of anaesthesia when suturing lacerations of the digits. A standard technique and questionnaire were applied to a consecutive group of 62 patients attending the Accident Department of the Bristol Royal Infirmary. Digital block was found to be a more effective technique than local infiltration for anaesthetising digital lacerations.

  8. Efficacy of b-lynch brace suture in postpartum haemorrhage

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

  9. Delayed-onset endophthalmitis associated with corneal suture infections

    Henry, Christopher R.; Flynn Jr., Harry W.; Miller, Darlene; Schefler, Amy C; Forster, Richard K.; Alfonso, Eduardo C.

    2013-01-01

    Background The purpose of the current study was to report the microbiology, risk factors, and treatment outcomes in patients with delayed-onset endophthalmitis associated with corneal suture infections. For this retrospective consecutive case series, a search of the ocular microbiology department database was performed to identify all patients with positive corneal and intraocular cultures (anterior chamber and/or vitreous) between 01 January 1995 and 01 January 2010. A subset of patients wit...

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

    Bahareh Kalantari

    2012-01-01

    Full Text Available 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 fiber. Moreover, the fraction of load carrying chains in various drawn polypropylene fibers was evaluated on the basis of simplified models.

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

    Kotek, Jiří; Kelnar, Ivan; Studenovský, Martin

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

  12. CRUDE PALM OIL AS A BIOADDITIVE IN POLYPROPYLENE BLOWN FILMS

    Emiliana Rose Jusoh,

    2012-01-01

    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.

  13. Effects of high-energy electron radiation on polypropylene dielectric

    Polypropylene, a polymeric materials widely used as the main dielectric in many high-voltage components such as capacitors and cables, was exposed to electron irradiation in air at room temperature. The 25.4-μm-thick dry polypropylene films were irradiated to different doses up to 108 rads with electron beam having energies of 0.5, 1.0, and 1.5 MeV. Monoisopropyl biphenyl (MIPB)-impregnated polypropylene films were also exposed to 1-MeV electron beam to doses up to 108 rads and the post-irradiation effects on the electrical, mechanical, and morphological and chemical properties of the films were evaluated. The electrical properties included the AC, DC and pulsed breakdown strengths, dielectric constant, dissipation factor, conductivity, and pulsed life-endurance. The mechanical properties comprised the Young's modulus, elongation-at-break, tensile strength, complex modulus, and mechanical loss. Finally, the morphological and chemical diagnoses carried out included surface morphology, elemental analysis, crystallinity changes, and identification of newly formed bonds and degree of oxidation. The results obtained indicate that the dry polypropylene films started to exhibit degradation at doses as low as 106 rads. The properties that were mostly affected included the film's tensile properties, pulsed life, dissipation factor, and electrical conductivity

  14. [INFLUENCE OF TITANIUM COATING ON THE BIOCOMPATIBILITY OF POLYPROPYLENE IMPLANTS].

    Babichenko, I I; Kazantsev, A A; Titarov, D L; Shemyatovsky, K A; Ghevondian, N M; Melchenko, D; Alekhin, A I

    2016-01-01

    Comparative analysis of the proliferative activity of inflammatory cells and distribution of collagen types I and III was carried out around the net materials of polypropylene and titanium coating polypropylene using im- munohistochemical method and polarization microscopy. Experimental modeling of implanted mesh material were made in the soft tissues of the lumbar region of rats. On the 7th postoperative day, quantitative analysis of proliferating cells delected using antibodies to the Ki-67 protein showed, a significant decrease (p Sirius red at polarizing light. On the 7th day after surgery, the ratio of collagen fibers ty- pe I and III in granulomas around the mesh material made of polypropylene was 1.085 ± 0.022 and this rati around materials of titanium coated polypropylene was higher--1.107 ± 0.013 (p = 0.017). On the 30th posto- perative day in the interface area ratio I/III collagen significantly increased and amounted to 1.174 ± 0.036 and 1.246 ± 0.102, respectively (p = 0.045). Assessing the impact of the use of titanium as a coating on the po- lypropylene, it can be argued that it promotes the formation of collagen I type and a more mature connective tis- sue around the mesh of the implants. PMID:27220251

  15. PLASTIC SHRINKAGE CONTROLLING EFFECT BY POLYPROPYLENE SHORT FIBER WITH HYDROPHILY

    Hosoda, Akira; Sadatsuki, Yoshitomo; Oshima, Akihiro; Ishii, Akina; Tsubaki, Tatsuya

    The aim of this research is to clarify the mechanism of controlling plastic shrinkage crack by adding small amout of synthetic short fiber, and to propose optimum polypropylene short fiber to control plastic shrinkage crack. In this research, the effect of the hydrophily of polypropylene fiber was investigated in the amount of plastic shrinkage of mortar, total area of plastic shrinkage crack, and bond properties between fiber and mortar. The plastic shrinkage test of morar was conducted under high temperature, low relative humidity, and constant wind velocity. When polypropylene fiber had hydrophily, the amount of plastic shrinkage of mortar was restrained, which was because cement paste in morar was captured by hydrophilic fiber and then bleeding of mortar was restrained. With hydrophily, plastic shrinkage of mortar was restrained and bridging effect was improved due to better bond, which led to remarkable reduction of plastic shrinkage crack. Based on experimental results, the way of developing optimum polypropylene short fiber for actual construction was proposed. The fiber should have large hydrophily and small diameter, and should be used in as small amount as possible in order not to disturb workability of concrete.

  16. Stress and strain analysis on the anastomosis site sutured with either epineurial or perineurial sutures after simulation of sciatic nerve injury

    Guangyao Liu; Qiao Zhang; Yan Jin; Zhongli Gao

    2012-01-01

    The magnitude of tensile stress and tensile strain at an anastomosis site under physiological stress is an important factor for the success of anastomosis following suturing in peripheral nerve injury treatment.Sciatic nerves from fresh adult cadavers were used to create models of sciatic nerve injury.The denervated specimens underwent epineurial and perineurial suturing.The elastic modulus (40.96 ± 2.59 MPa) and Poisson ratio (0.37 ± 0.02) of the normal sciatic nerve were measured by strain electrical measurement.A resistance strain gauge was pasted on the front,back,left,and right of the edge of the anastomosis site after suturing.Strain electrical measurement results showed that the stress and strain values of the sciatic nerve following perineurial suturing were lower than those following epineurial suturing.Scanning electron microscopy revealed that the sciatic nerve fibers were disordered following epineurial compared with perineurial suturing.These results indicate that the effect of perineurial suturing in sciatic nerve injury repair is better than that of epineurial suturing.

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

    Mirković Siniša

    2011-01-01

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

  18. Rheometric research of polypropylene Licocene PP2602 melts

    V.V. Romanuke

    2011-07-01

    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

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

    Thomassin, Jean-Michel; Huynen, Isabelle; Jérôme, Robert; Detrembleur, Christophe

    2010-01-01

    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 (

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

    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

  1. 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

    Marcelo Seixo de Brito e Silva

    2010-08-01

    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.

  2. A novel platelet-rich arterial thrombosis model in rabbits. Simple, reproducible, and dynamic real-time measurement by using double-opposing inverted-sutures model.

    Shieh, S J; Chiu, H Y; Shi, G Y; Wu, C M; Wang, J C; Chen, C H; Wu, H L

    2001-09-01

    Though numerous animal thrombosis models have been introduced, an easy, reliable, and reproducible arterial thrombosis model remains a continuing challenge prior to a thrombolytic study. In an effort to evaluate the efficiency of various recombinant thrombolytic agents with specific affinity to activated platelets in vivo, we developed a novel double-opposing inverted-sutures model to create a platelet-rich thrombus in the femoral artery of rabbits. The arteriotomy was done semicircumferentially, and variously sized microsurgical sutures were introduced intraluminally in a double-opposing inverted manner. The animals were divided into three groups according to the double-opposing inverted-sutures used: Group 1 with 10-0 nylon (n=6), Group 2 with 9-0 nylon (n=6), and Group 3 with 8-0 nylon (n=22). The superficial epigastric branch was cannulated with a thin polyethylene (PE) tube for intraarterial administration of the studied thrombolytic agent. The blood flow was continuously measured with a real-time ultrasonic flow meter. Within 2 h of installation of the sutures, there was no thrombus formation in either Group 1 or 2. In Group 3, the thrombosis rate was 91% (20 of 22) under a steady baseline flow (with an average of 12.23+/-2.40 ml/min). It was highly statistically significant with a P-value of .0000743 using Fisher's Exact Test. The averaged time to thrombosis was 21.8+/-9.8 min. The ultrasonic flow meter to record the dynamic real-time measurement of blood flow was a guideline for thrombus formation or dissolution, which was correlated with the morphological findings of stenotic status of the vessel detected by the Doppler sonography. The components of the thrombus were proven to be platelet-rich predominant by histological examination via hematoxylin and eosin (H&E) stain and transmission electron microscopy (TEM). To confirm that the double-opposing inverted-sutures model would be useful for a study of thrombolytic agents, we evaluated the effects of

  3. Tissue reactions to suture materials in the oral mucosa of beagle dogs

    Kim, Jae-Seok; Shin, Seung-Il; Herr, Yeek; Park, Joon-Bong; Kwon, Young-Hyuk; Chung, Jong-Hyuk

    2011-01-01

    Purpose The objective of this study was to compare and evaluate the inflammatory responses of three widely used suture materials in the keratinized gingiva and buccal mucosa of beagle dogs. Methods Silk, polyglycolic acid, and nylon sutures were placed within the mandibular keratinized gingiva and maxillary buccal mucosa of four male beagle dogs. Biopsies were taken 3, 7, and 14 days after suturing. Specimens were prepared with hematoxylin-eosin stain for evaluation under a light microscope. ...

  4. The Effect of Different Suturing Techniques on Astigmatism after Penetrating Keratoplasty

    Kim, Sang Jin; Wee, Won Ryang; Lee, Jin Hak; Kim, Mee Kum

    2008-01-01

    The purpose of this study was to compare the effects on astigmatism after penetrating keratoplasty with three different suture techniques. In this prospective study, 38 eyes of 38 patients underwent penetrating keratoplasty with three suturing techniques: interrupted, single running, and double running. Topographic astigmatism was measured at 2, 6, 12, and 18 months after keratoplasty. During 18 months after surgery, the interrupted suture group had higher astigmatism than the double running ...

  5. Stem cells of the suture mesenchyme in craniofacial bone development, repair and regeneration

    Maruyama, Takamitsu; Jeong, Jaeim; Sheu, Tzong-jen; Hsu, Wei

    2016-01-01

    The suture mesenchyme serves as a growth centre for calvarial morphogenesis and has been postulated to act as the niche for skeletal stem cells. Aberrant gene regulation causes suture dysmorphogenesis resulting in craniosynostosis, one of the most common craniofacial deformities. Owing to various limitations, especially the lack of suture stem cell isolation, reconstruction of large craniofacial bone defects remains highly challenging. Here we provide the first evidence for an Axin2-expressin...

  6. Polypropylene/Graphene and Polypropylene/Carbon Fiber Conductive Composites: Mechanical, Crystallization and Electromagnetic Properties

    Chien-Lin Huang

    2015-11-01

    Full Text Available This study aims to examine the properties of composites that different carbon materials with different measurements can reinforce. Using a melt compounding method, this study combines polypropylene (PP and graphene nano-sheets (GNs or carbon fiber (CF to make PP/GNs and PP/CF conductive composites, respectively. The DSC results and optical microscopic observation show that both GNs and CF enable PP to crystalize at a high temperature. The tensile modulus of PP/GNs and PP/CF conductive composites remarkably increases as a result of the increasing content of conductive fillers. The tensile strength of the PP/GNs conductive composites is inversely proportional to the loading level of GNs. Containing 20 wt% of GNs, the PP/GNs conductive composites have an optimal conductivity of 0.36 S/m and an optimal EMI SE of 13 dB. PP/CF conductive composites have an optimal conductivity of 10−6 S/m when composed of no less than 3 wt% of CF, and an optimal EMI SE of 25 dB when composed of 20 wt% of CF.

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

    2010-10-01

    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.

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

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

    2009-11-01

    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

  9. Mechanical Properties of Cranial Bones and Sutures in 1–2-Year-Old Infants

    Wang, Jiawen; Zou, Donghua; LI, ZHENGDONG; Huang, Ping; Li, Dongri; Shao, Yu; Wang, Huijun; Chen, Yijiu

    2014-01-01

    Background The mechanical properties of 1–2-year-old pediatric cranial bones and sutures and their influential factors were studied to better understand how the pediatric calvarium reacts to loading. Material/Methods Cranial bone and suture specimens were extracted from seven fresh-frozen human infant cadavers (1.5±0.5 years old). Eight specimens were obtained from each subject: two frontal bones, two parietal bones, two sagittal suture samples, and two coronal suture samples. The specimens w...

  10. Biomechanical study on the suture strength of ligament in cruciate ligament reconstruction

    张春礼; 李起鸿; 杨柳

    2003-01-01

    Objective: To test the suture strength on the tendon or ligament end and evaluate the stitch in the reconstruction of cruciate ligament and its clinical application. Methods: Twenty-four specimens of patellar tendon with free ends were divided into 3 groups: Group I (3 Krackow stitches), Group II (2 Krackow stitches) and Group III (2 Krackow stitches with the first stitch passing through the tendon tissue as a modified Krackow stitch). These 3 groups were further divided into 6 subgroups according to different suture materials, No 1 Ethilon or stainless steel wire (φ= 0.4 mm). Tensile test was undertaken to find out the least stitches with efficient suture pattern. Results: Two Krackow locking stitches had stronger strength than 0.4 mm-diameter stainless steel wire. The fixation strength of 2 stitches with No 1 Ethilon was more than 80 N, superior to the failure strength of the material itself. The same strength was maintained if the first stitch was across the tendon tissue transversely. There was no statistically significant difference in the suture strength between 2 and 3 Krackow locking stitches. Conclusions: The suture strength is greater than the failure strength of the suture material. Less suture exposure can be achieved when the first stitch is across the tendon tissue while maintaining a comparable strength to other sutures. To attain higher suture strength, stronger materials or multiple strands rather than more stitches are preferred. Therefore, a rapid early rehabilitation of range of motion (ROM) is possible and reliable in practice.

  11. Surgical sutures filled with adipose-derived stem cells promote wound healing.

    Ann Katharin Reckhenrich

    Full Text Available Delayed wound healing and scar formation are among the most frequent complications after surgical interventions. Although biodegradable surgical sutures present an excellent drug delivery opportunity, their primary function is tissue fixation. Mesenchymal stem cells (MSC act as trophic mediators and are successful in activating biomaterials. Here biodegradable sutures were filled with adipose-derived mesenchymal stem cells (ASC to provide a pro-regenerative environment at the injured site. Results showed that after filling, ASCs attach to the suture material, distribute equally throughout the filaments, and remain viable in the suture. Among a broad panel of cytokines, cell-filled sutures constantly release vascular endothelial growth factor to supernatants. Such conditioned media was evaluated in an in vitro wound healing assay and showed a significant decrease in the open wound area compared to controls. After suturing in an ex vivo wound model, cells remained in the suture and maintained their metabolic activity. Furthermore, cell-filled sutures can be cryopreserved without losing their viability. This study presents an innovative approach to equip surgical sutures with pro-regenerative features and allows the treatment and fixation of wounds in one step, therefore representing a promising tool to promote wound healing after injury.

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

    Tiong, William H C

    2011-09-01

    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.

  13. Microarterial anastomoses: A parameterised computational study examining the effect of suture position on intravascular blood flow.

    Wain, R A J; Hammond, D; McPhillips, M; Whitty, J P M; Ahmed, W

    2016-05-01

    This study investigates the extent to which individual aspects of suture placement influence local haemodynamics within microarterial anastomoses. An attempt to physically quantify flow characteristics of blood past microvascular sutures is made using computational fluid dynamics (CFD) software. Particular focus has been placed on increased shear strain rate (SSR), a known precipitant of intravascular platelet activation and thrombosis. Measurements were taken from micrographs of sutured anastomoses in chicken femoral vessels, with each assessed for bite width, suture angle and suture spacing. Computational geometries were then created to represent the anastomosis. Each suture characteristic was parameterised to allow independent or simultaneous adjustment. Flow rates were obtained from anonymised Doppler ultrasound scans of analogous vessels during preoperative assessment for autologous breast reconstruction. Vessel simulations were performed in 2.5mm ducts with blood as the working fluid. Vessel walls were non-compliant and a continuous Newtonian flow was applied, in accordance with current literature. Suture bite angle and spacing had significant effects on local haemodynamics, causing notably higher local SSRs, when simulated at extremes of surgical practice. A combined simulation, encompassing subtle changes of each suture parameter simultaneously i.e. representing optimum technique, created a more favourable SSR profile. As such, haemodynamic changes associated with optimum suture placement are unlikely to influence thrombus formation significantly. These findings support adherence to the basic principles of good microsurgical practice. PMID:26876115

  14. Destructive tests on low voltage metallized polypropylene capacitors

    Cesari, S.

    1988-08-01

    This paper gives the results of destructive tests conducted on low voltage capacitors with metallized polypropylene dielectrics of the dry and impregnated types. The purpose of the tests was to check the behaviour of capacitors of the self-healing type in the event of a dielectric failure. A failure in the self-healing process of metallized polypropylene capacitors is usually accompanied by an increase in inside pressure which can cause the explosion in the casing if the capacitor is not equipped with a proper safety device. The tests were performed in accordance with ENEL (Italian Electricity Board) specifications. The effects of different test parameters, such as dielectric temperature and short-circuit current, were investigated and the results of the experiments were compared with those obtained in service and during service life tests.

  15. Properties of Recycled Aggregate Concrete Reinforced with Polypropylene Fibre

    Wan Mohammad Wan Nur Syazwani

    2016-01-01

    Full Text Available This research work is aimed to investigate how the addition of various proportion of polypropylene fibre affects the mechanical strength and permeability characteristics of recycled aggregate concrete (RAC which has been produced with treated coarse recycled concrete aggregate (RCA. Further research on RAC properties and their applications is of great importance as the scarcity of virgin aggregate sources in close proximity to major urban centers is becoming a worldwide problem. In this study, the hardened RAC properties at the curing age of 7 and 28 days such as compressive strength, flexural strength, ultrasonic pulse velocity (UPV, water absorption and total porosity were evaluated and compare with control specimens. Experimental result indicates that although the inclusion of the treated coarse RCA can enhance the mechanical strength and permeability properties of RAC, Further modification by addition of polypropylene fibre can optimize the results.

  16. DSC Study on Polypropylene Modified with Calcium Carbonate Nanoparticles

    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 γ 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

  17. Ziegler-Natta catalyst for polypropylene and polyethylene nanocomposites preparation

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

  18. Effects of environmental ageing on HMS-polypropylene/Cloisite nanocomposites

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

    2014-05-15

    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.

  19. Oxygen barrier property of polypropylene-polyether treated clay nanocomposite

    2008-06-01

    Full Text Available Polypropylene (PP nanocomposites were obtained by solution blending of polyether treated montmorillonite and PP, with a coupling agent of maleic anhydride grafted polypropylene (PP-g-MA. The composition of the inorganic clay was varied in 1, 2 and 5 phr (parts of clay per hundred of PP by mass while films of the composites were obtained via compression molding. Wide-angle X-ray scattering (WAXS showed nanocomposites in which silicate layers were exfoliated and intercalated with respect to the different clay ratios. The morphology and gas permeability of hybrids prepared with organoclay were compared. Morphological studies using transmission electron microscopy showed most clay layers were dispersed uniformly in the PP matrix. Some tactoids of agglomerated nanoparticles were detected, as clay content increased. The oxygen permeability for all the hybrids for clay loadings were reduced by 30% of the corresponding values for pure PP.

  20. Thermal simulation for geometric optimization of metallized polypropylene film capacitors

    El-Husseini, M.,; VENET, Pascal; Rojat, Gérard; Joubert, Charles

    2002-01-01

    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.

  1. Modification of bentonite clay and application on polypropylene nano composites

    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)

  2. Partial Discharge Degradation and Breakdown Studies in Polypropylene Films

    Thomas, Benny; Nema, RS

    1996-01-01

    Internal partial discharge characteristics are investigated on impregnated polypropylene films containing artificial cavity of well-defined dimensions, immersed in oil. Electrical breakdown studies are carried out at step-wise rising stress to evaluate constants of inverse power law model. Partial discharge pulse distribution patterns are acquired using PC interfaced multichannel analyser and statistical analysis of the discharge pulse spectrum is done by using 3-parameter Weibull distributio...

  3. Properties of recycled polypropylene based composites incorporating treated hardwood sawdust

    Shulga, Galia; Jaunslavietis, Jevgenijs; Ozolins, Jurijs; Neiberte, Brigita; Verovkins, Anrijs; Vitolina, Sanita; Shakels, Vadims

    2016-05-01

    The effect of different treatment of hardwood sawdust under mild conditions on contact angles, adhesion energy and water sorption was studied. A comparison of these indices for the hardwood treated sawdust and the composites filled with them was performed. The treatment promoted the compatibility between the recycled polypropylene and the hardwood filler. The inclusion of the lignin-based compatibiliser in the composite, containing the ammoxidised wood filler, essentially improved its mechanical properties.

  4. Functional Block Copolymers as Compatibilizers for Nanoclays in Polypropylene Nanocomposites

    Jankova Atanasova, Katja; Daugaard, Anders Egede; Stribeck, Norbert;

    With the aim of creating tough nanocomposits (NC) [1] based on polypropylene (PP) and nanoclay (NCl) in the framework of the 7th EU program NANOTOUGH we have designed amphiphilic block copolymers utilizing Atom Transfer Radical Polymerization (ATRP) [2]. They consist of a hydrophobic block of...... PP (by its crystallites) is replaced by alien-reinforcement (of the MMT). Furthermore, the results from the impact strength and cyclic test of the prepared PP nanocomposites [3] are promicing....

  5. Microstructure and Properties of Polypropylene/Carbon Nanotube Nanocomposites

    Dimitrios Bikiaris

    2010-01-01

    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...

  6. INTERACTION BETWEEN ISOTACTIC POLYPROPYLENE AND ITS NON-SOLVENTS

    ZHAO Chuntian; HOU Jianan; ZHANG Xian; ZHU Wei; XU Mao

    1996-01-01

    Polypropylene (PP) microporous film prepared by biaxial stretching of isotactic PP is treated with non-solvent liquid at room temperature. The dimension of the film may change after the treatment. The degree of area contraction of PP film is dependent on the match between PP and liquid in solubility parameter and polarity. The fact indicates that some interactions do exist between liquid and isotactic PP, and a shrinkable porous film is a sensitive probe to detect the weak interactions.

  7. Bacterial Growth on Chitosan-Coated Polypropylene Textile

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

    2012-01-01

    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...

  8. Surface modification of polypropylene membrane by polyethylene glycol graft polymerization

    Polypropylene hollow fiber microporous membranes have been used in a wide range of applications, including blood oxygenator. The hydrophobic feature of the polypropylene surface causes membrane fouling. To minimize fouling, a modification consisting of three steps: surface activation in H2 and O2 plasma, membrane immersion in polyethylene glycol (PEG) and plasma graft polymerization was performed. The membranes were characterized by contact angle measurement, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), tensile test, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Oxygen transfer of modified membranes was also tested. The stability of grafted PEG was measured in water and in phosphate buffer saline (PBS) at 37 °C. Blood compatibility of modified surfaces was evaluated by the platelet adhesion method. Water contact angel reduction from 110° to 72° demonstrates the enhanced hydrophilicity, and XPS results verify the presence of oxygenated functional groups due to the peak existence in 286 eV as a result of PEG grafting. The results clearly indicate that plasma graft-polymerization of PEG is an effective way for antifouling improvement of polypropylene membranes. Also, the results show that oxygen transfer changes in PEG grafted membranes are not significant. - Highlights: • H2 and O2 plasma graft polymerization of PEG on polypropylene membrane was carried out. • Changes in surface properties were investigated by FTIR, XPS, SEM, and AFM. • Surface wettability enhanced as a result of poly ethylene glycol grafting. • PEG grafting degree increase causes reduction of fouling and adhesion

  9. Polypropylene/organoclay/SEBS nanocomposites with toughness-stiffness properties

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

    2014-01-01

    Polypropylene nanocomposites with a different amount of styrene-ethylene-butylene-styrene block copolymer (SEBS)/clay were prepared via a melt mixing technique. To improve the dispersion of commercial organoclay (denoted as OMMT), various amounts of SEBS were incorporated. At a fixed content of O...... nanomaterials presented an improved decomposition temperature, a small decrease in tensile strength, a higher Young's modulus and a spectacular increase of 300% in impact strength....

  10. Property Relationship in Organosilanes and Nanotubes Filled Polypropylene Hybrid Composites

    Alejandra J. Monsiváis-Barrón; Jaime Bonilla-Rios; Antonio Sánchez-Fernández

    2014-01-01

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

  11. Mechanical and morphological characterization of polypropylene toughened with olefinic elastomer

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

    2000-01-01

    The effect of incorporating (C2-C8) ethylene-octene elastomer on the mechanical properties and morphology of polypropylene copolymers has been investigated employing two types of PP copolymer, with and without nucleating agent. The results were compared to the ones presented by a commercial PP heterophase (reactor impact modified PP/EPR). The addition of the elastomer increases the toughness of the blends but reduces their stiffness. PP blends in the low elastomer content region (< 20%) show ...

  12. Surface modification of polypropylene membrane by polyethylene glycol graft polymerization

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

    2014-09-01

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

  13. Thermal degradation and viscoelasticity of polypropylene-clay nanocomposites

    Drozdov, A. D.; Al-Mulla, A.; Drozdov, D. A.; Gupta, R. K.

    2003-01-01

    Results of torsional oscillation tests are reported that were performed at the temperature T=230C on melts of a hybrid nanocomposite consisting of isotactic polypropylene reinforced with 5 wt.% of montmorillonite clay. Prior to mechanical testing, specimens were annealed at temperatures ranging from 250 to 310C for various amounts of time (from 15 to 420 min). Thermal treatment induced degradation of the matrix and a pronounced decrease in its molecular weight. An integro-differential equatio...

  14. Dynamic Mechanical Properties of Wood Powder /Polypropylene Composites

    2003-01-01

    The dynamic mechanical properties of wood powder/polypropylene composites with different wood content treated and untreated with the compatibilizer have been studied. It has been found that addition of wood powders and the compatibilizer can both improve the viscoelasticity of composites. Glass transition temperature (Tg) of appropriate wood powder-filled composites decreased. The value for the storage modulus (G') increased gradually with increasing wood powder content. The addition of the compatibiliz...

  15. Reinforcing Efficiency of Crimped Profile of Polypropylene Fibres on the Cementitious Matrix

    S. Thirumurugan; V.M. Sounthararajan; Mr. A. Sivakumar

    2013-01-01

    Fibre reinforcement in concrete is an effective solution for improving tensile properties of concrete. Different types of fibres such as steel, polypropylene, glass and polyester were commonly used in concrete. In the present study, the effect of adding crimped polypropylene fibres on the improvement in the compressive properties of hardened concrete was studied. Crimped polypropylene fibres with different levels of reinforcements index was investigated systematically with designed concrete m...

  16. Newly Designed Polypropylene Polyol with Terminated Primary Hydroxy Group and Application for Polyurethane Foam

    K.Maeda; M.Kaku; Y.Sakural; K.Nishiyama; H.Nakaminami

    2007-01-01

    1 Results Polypropylene polyol is very important chemical materials for polyurethane. We developed newly designed polypropylene polyol with terminated primary hydroxyl group. We focus on our new polypropylene polyol, and show its useful application for polyurethane foam. Polymerization of propyleneoxide is conventionally carried out in anionic polymerization process. In anionic process α-cleavage of propyleneoxide occurs rather than β-cleavage. Then the terminal hydroxyl group of the resulting polypropy...

  17. Effect of recycling on properties of rice husk-filled-polypropylene

    Jutarat Prachayawarakorn; Niracha Yaembunying

    2005-01-01

    This research concerned with the use of rice husk (Oryza sativa) as a filler for polypropylene and its recycle ability. Rice husk (200 mesh and 40% by weight) and polypropylene were compounded in a twinscrew extruder and injection moulding technique was applied in order to obtain testing specimens. It was found that tensile, flexural and impact properties as well as % water absorption of the rice husk-filled polypropylene were only slightly dropped upon recycling process, presenting the abili...

  18. Antibacterial Surgical Silk Sutures Using a High-Performance Slow-Release Carrier Coating System.

    Chen, Xiaojie; Hou, Dandan; Wang, Lu; Zhang, Qian; Zou, Jiahan; Sun, Gang

    2015-10-14

    Sutures are a vital part for surgical operation, and suture-associated surgical site infections are an important issue of postoperative care. Antibacterial sutures have been proved to reduce challenging complications caused by bacterial infections. In recent decades, triclosan-free sutures have been on their way to commercialization. Alternative antibacterial substances are becoming relevant to processing surgical suture materials. Most of the antibacterial substances are loaded directly on sutures by dipping or coating methods. The aim of this study was to optimize novel antibacterial braided silk sutures based on levofloxacin hydrochloride and poly(ε-caprolactone) by two different processing sequences, to achieve suture materials with slow-release antibacterial efficacy and ideal physical and handling properties. Silk strands were processed into sutures on a circular braiding machine, and antibacterial treatment was introduced alternatively before or after braiding by two-dipping-two-rolling method (M1 group and M2 group). The antibacterial activity and durability against Staphylococcus aureus and Escherichia coli were tested. Drug release profiles were measured in phosphate buffer with different pH values, and release kinetics model was built to analyze the sustained drug release mechanism between the interface of biomaterials and the in vitro aqueous environment. Knot-pull tensile strength, thread-to-thread friction, and bending stiffness were determined to evaluate physical and handling properties of sutures. All coated sutures showed continuous antibacterial efficacy and slow drug release features for more than 5 days. Besides, treated sutures fulfilled U.S. Pharmacopoeia required knot-pull tensile strength. The thread-to-thread friction and bending stiffness for the M1 group changed slightly when compared with those of uncoated ones. However, physical and handling characteristics of the M2 group tend to approach those of monofilament ones. The novel suture

  19. Property Relationship in Organosilanes and Nanotubes Filled Polypropylene Hybrid Composites

    Alejandra J. Monsiváis-Barrón

    2014-10-01

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

  20. Flame retardant polypropylene nanocomposites reinforced with surface treated carbon nanotubes

    Guleria, Abhishant

    Polypropylene nanocomposites are prepared by reinforcing carbon nanotubes by ex-situ solution mixing method. Interfacial dispersion of carbon nanotubes in polypropylene have been improved by surface modification of CNTs and adding surfactants. Polypropylene nanocomposites fabrication was done after treating CNTs. Firstly, oxidation of CNTs followed by silanization for addition of functionalized groups on the surface of CNTs. Maleic anhydride grafted PPs were used as surfactants. Maleic anhydrides with two different molecular weights were LAMPP and HMAPP. Successful oxidation of CNTs by nitric acid and functionalized CNTs by 3-Aminopropyltriethoxysilane was confirmed by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) with evidence of absorption peak at 1700 and 1100-1000 cm-1. Scanning electron microscopy (SEM) micrographs revealed that the CNTs dispersion quality was improved by directly adding LMAPP/HMAPP into PP/CNTs system and the PP-CNTs adhesion was enhanced through both the CNTs surface treatment and the addition of surfactant. Thermal gravimetric analysis (TGA) revealed an enhanced thermal stability in the PP/CNTs and PP/CNTs/MAPP. Differential scanning calorimetry (DSC) characterization demonstrated that the crystalline temperature, fusion heat and crystalline fraction of hosting PP were decreased with the introduction of CNTs and surface treated CNTs; however, melting temperature was only slightly changed. Melting rheological behaviors including complex viscosity, storage modulus, and loss modulus indicated significant changes in the PP/MAPP/CNTs system before and after functionalization of CNTs, and the mechanism were also discussed in details.

  1. Mixing of Isotactic and Syndiotactic Polypropylenes in the Melt

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

    2000-07-14

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

  2. Pubovaginal sling with a low-cost polypropylene mesh

    Fransber R. Rodrigues

    2007-10-01

    Full Text Available OBJECTIVE: The aim of this study was to present the results of pubovaginal sling with a low-cost polypropylene mesh in the treatment of stress urinary incontinence MATERIALS AND METHODS: 118 women diagnosed with stress urinary incontinence (SUI due to urethral hypermobility or intrinsic sphincteric deficiency, treated with pubovaginal sling (PVS with a low-cost polypropylene mesh confectioned by the surgeon, were analyzed. All patients had a basic evaluation that included a medical history, physical examination, stress tests and urodynamic investigation RESULTS: The average follow up was of 42 months. Urethral hypermobility was observed in 67% of the cases. The process was carried out on an outpatient basis on 67 patients. Intra-operative complications included 4 vesical injuries, treated with catheterization for 3 days. There were 13 early complications, of which 8 were urinary retentions treated with vesical drainage for 1 to 3 weeks and 3 vaginal extrusions of the mesh treated with covering of the sections with mucous membrane. There was a need for 6 urethrolysis in patients who presented irritative and postoperative obstructive symptoms; 81.3% of the patients were considered cured, while 9.3% had significant improvement. Three initially unsuccessful cases required sling reconfiguration. All cases were eventually cured CONCLUSION: The construction of a pubovaginal sling using a low-cost polypropylene mesh is a safe and effective technique for the relief of SUI. It should be considered an alternative, especially for patients in public health systems with low financial resources.

  3. The fourth suture in MACS facelifting – adressing the neck

    Kaye, Kai O.

    2014-12-01

    Full Text Available Objective: The MACS facelift alone shows poor results on the medial neck in cases of pronounced, rigid platysmabands (McKinney III–IV°. The original MACS (“Minimal Access Cranial Suspension” facelift delirs excellent results on the midface and leads to sustainably improved outcome on the neck by adding a fourth suture on the platysma. McKinney type I–II platysmabands can be treated only by lateral approach of the ‘fourth suture’, type III–IV should be treated with closed platysma myotomy before.Methods: Between October 2007 and November 2013 a number of 219 patients were treated with the MACS facelift technique accomplished by a fourth suture on the platysma and liposuction or optional lipectomy on the neck. On 47 patients closed transcutaneous platysma myotomy was performed.Results: Surgery time lasted on average 2.5 hours and was performed under sedation with local anesthesia in 85%. Recovery time ranged between 14 to 16 days until the patients were back to work. Due to their health status 54% of our patients had an inpatient arrangement for one night and 46% an outpatient arrangement.Conclusion: The modification of the MACS lift with the ‘fourth suture’ on the platysma keeps the benefits of the original technique but improves the aesthetic outcome on the neck.

  4. Modified arthroscopic suture fixation of a displaced tibial eminence fracture.

    Lehman, Ronald A; Murphy, Kevin P; Machen, M Shaun; Kuklo, Timothy R

    2003-02-01

    This study describes a new arthroscopic method using a whip-stitch technique for treating a displaced type III tibial eminence fracture. A 12-year-old girl who sustained a displaced type III tibial eminence fracture was treated with arthroscopic fixation using the Arthrosew disposable suture device (Surgical Dynamics, Norwalk, CT) to place a whip stitch into the anterior cruciate ligament (ACL). The Arthrex ACL guide (Arthrex, Naples, FL) was used to reduce the avulsed tibial spine fragment. Sutures were then passed through the tibial tunnel and secured over a bony bridge with the knee in 20 degrees of flexion. At 9 months, the patient has a full range of motion with normal Lachman and anterior drawer testing, and she has returned to competitive basketball. Radiographs show complete fracture healing. KT-1000 and isokinetic testing at 9-month follow-up show only minimal side-to-side differences. The Arthrosew device 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 ACL, thus obviating arthrotomy and hardware placement. This technique also restores the proper length and tension to the ACL, and provides a simplified, reproducible method of treatment for this injury. PMID:12579135

  5. The effect of electrostatic force on air filtration by polypropylene filter media

    In this paper, the effect of irradiation with 60Co on the efficiency and strength of the polypropylene filter media is mainly researched. The charge density of polypropylene fibre is evaluated by radiation discharge method. Based on isolated cylinder model, the efficiency of the polypropylene filter media, which takes account of the effect of impaction, interception, diffusion and electrostatic, is calculated. A better agreement between theoretical analysis and experimental results is obtained. The results indicate that electrostatic force is the most important factor in solid aerosol filtration of the polypropylene filter media

  6. Cork extractives exhibit thermo-oxidative protection properties in polypropylene-cork composites and as direct additives for polypropylene

    Aroso, Ivo Manuel Ascensão; Fernandes, E. M.; Pires, R. A.; Mano, J. F.; Reis, R L

    2015-01-01

    The thermo-oxidative stability of polypropylene (PP) in composites containing 15 wt.% of cork and the performance of selected cork extracts as stabilizing additives for PP was evaluated by Oxidation Induction Time (OIT) and by Oxidation Onset Temperature (OOT). The results showed that cork increases the OIT of PP in the composite and it was identified that the cork extractives fraction is responsible for such behavior. Selected cork extracts with high antioxidant capacity (determined by dpph ...

  7. Faraday rotation of the supernova remnant G296.5+10.0: Evidence for a Magnetized Progenitor Wind

    Harvey-Smith, L; Kothes, R; Townsend, R; Heald, G H; Ng, C -Y; Green, A J

    2010-01-01

    We present spectropolarimetric radio images of the supernova remnant (SNR) G296.5+10.0 at frequencies near 1.4 GHz, observed with the Australia Telescope Compact Array. By applying rotation measure (RM) synthesis to the data, a pixel-by-pixel map of Faraday rotation has been produced for the entire remnant. We find G296.5+10.0 to have a highly ordered RM structure, with mainly positive RMs (mean RM of +28 rad/m**2) on the eastern side and negative RMs (mean RM of -14 rad/m**2) on the western side, indicating a magnetic field which is directed away from us on one side and toward us on the other. We consider several possible mechanisms for creating the observed RM pattern. Neither Faraday rotation in foreground interstellar gas nor in a homogeneous ambient medium swept up by the SNR shell can easily explain the magnitude and sign of the observed RM pattern. Instead, we propose that the observed RMs are the imprint of an azimuthal magnetic field in the stellar wind of the progenitor star. Specifically, we calcul...

  8. Mainpack 10.0. Software para la gestión de la actividad de mantenimiento en la industria azucarera

    Santiago Estupiñán-Díaz

    2015-01-01

    Full Text Available El mantenimiento es una actividad de vital importancia en la industria; al aplicarse se logra un mayor alargamiento de la vida útil del equipo, una reducción significativa de los costos en reparación y gastos en repuestos, así como de aquellos gastos que incurren en la mano de obra ligada a la actividad. En el presente trabajo se expone Mainpack 10.0, un sistema para la gestión del mantenimiento y las reparaciones del equi- pamiento en la industria azucarera. Al automatizar el proceso de mantenimiento, incorporando una herramienta informática como MainPack 10.0 se agilizan y controlan eficientemente todos los aspectos organizativos y financieros de la actividad de mantenimiento. Para el desarrollo de esta aplicación de gestión del mantenimiento asistido por ordenador (GMAO se ana- lizaron una serie de actividades que se realizan duran- te el proceso de mantenimiento, como son: planificación, identificación del equipamiento, incidencias, pasaportes o fichas técnicas del equipo, diagnósticos, etc. El software presenta una interfaz amigable y las funcionalidades incluidas en su diseño facilitan su uso y explotación. En este trabajo se ofrecen datos reales del sistema para demostrar su utilidad y posibilidades.

  9. Monotonic and cyclic responses of impact polypropylene and continuous glass fiber-reinforced impact polypropylene composites at different strain rates

    Yudhanto, Arief

    2016-03-08

    Impact copolymer polypropylene (IPP), a blend of isotactic polypropylene and ethylene-propylene rubber, and its continuous glass fiber composite form (glass fiber-reinforced impact polypropylene, GFIPP) are promising materials for impact-prone automotive structures. However, basic mechanical properties and corresponding damage of IPP and GFIPP at different rates, which are of keen interest in the material development stage and numerical tool validation, have not been reported. Here, we applied monotonic and cyclic tensile loads to IPP and GFIPP at different strain rates (0.001/s, 0.01/s and 0.1/s) to study the mechanical properties, failure modes and the damage parameters. We used monotonic and cyclic tests to obtain mechanical properties and define damage parameters, respectively. We also used scanning electron microscopy (SEM) images to visualize the failure mode. We found that IPP generally exhibits brittle fracture (with relatively low failure strain of 2.69-3.74%) and viscoelastic-viscoplastic behavior. GFIPP [90]8 is generally insensitive to strain rate due to localized damage initiation mostly in the matrix phase leading to catastrophic transverse failure. In contrast, GFIPP [±45]s is sensitive to the strain rate as indicated by the change in shear modulus, shear strength and failure mode.

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

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

  11. Failure of B-Lynch Compression Suture in a Patient with Couvelaire Uterus and Uterine Atony

    Pınar Çilesiz Göksedef

    2016-03-01

    Full Text Available In this paper, we aimed to discuss the reliability of B-Lynch suture, especially in patients with Couveliare uterus, and to present a patient who underwent bilateral uterine artery ligation in addition to B-Lynch compression suture for uterine atony resulting from abruptio placentae and developed retroperitoneal hematoma due to uterine laceration in the postpartum period.

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

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

    1995-01-01

    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.

  13. 21 CFR 878.4494 - Absorbable poly(hydroxybutyrate) surgical suture produced by recombinant DNA technology.

    2010-04-01

    ... produced by recombinant DNA technology. 878.4494 Section 878.4494 Food and Drugs FOOD AND DRUG... recombinant DNA technology. (a) Identification. An absorbable poly(hydroxybutyrate) surgical suture is an...) Surgical Suture Produced by Recombinant DNA Technology.” For the availability of this guidance document...

  14. The importance of craniofacial sutures in biomechanical finite element models of the domestic pig.

    Jen A Bright

    Full Text Available Craniofacial sutures are a ubiquitous feature of the vertebrate skull. Previous experimental work has shown that bone strain magnitudes and orientations often vary when moving from one bone to another, across a craniofacial suture. This has led to the hypothesis that craniofacial sutures act to modify the strain environment of the skull, possibly as a mode of dissipating high stresses generated during feeding or impact. This study tests the hypothesis that the introduction of craniofacial sutures into finite element (FE models of a modern domestic pig skull would improve model accuracy compared to a model without sutures. This allowed the mechanical effects of sutures to be assessed in isolation from other confounding variables. These models were also validated against strain gauge data collected from the same specimen ex vivo. The experimental strain data showed notable strain differences between adjacent bones, but this effect was generally not observed in either model. It was found that the inclusion of sutures in finite element models affected strain magnitudes, ratios, orientations and contour patterns, yet contrary to expectations, this did not improve the fit of the model to the experimental data, but resulted in a model that was less accurate. It is demonstrated that the presence or absence of sutures alone is not responsible for the inaccuracies in model strain, and is suggested that variations in local bone material properties, which were not accounted for by the FE models, could instead be responsible for the pattern of results.

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

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

    2011-01-01

    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.

  16. Antibacterial-Coated Suture in Reducing Surgical Site Infection in Breast Surgery: A Prospective Study

    Enora Laas

    2012-01-01

    Full Text Available Background. To reduce the incidence of microbial colonization of suture material, Triclosan- (TC-coated suture materials have been developed. The aim of this study was to assess the incidence of suture-related complications (SRC in breast surgery with and without the use of TC-coated sutures. Methods. We performed a study on two consecutive periods: 92 patients underwent breast surgery with conventional sutures (Group 1 and 98 with TC-coated sutures (Group 2. We performed subgroups analyses and developed a model to predict SRC in Group 1 and tested its clinical efficacy in Group 2 using a nomogram-based approach. Results. The SRC rates were 13% in Group 1 and 8% in Group 2. We found that some subgroups may benefit from TC-coated sutures. The discrimination obtained from a logistic regression model developed in Group 1 and based on multifocality, age and axillary lymphadenectomy was 0.88 (95% CI 0.77–0.95 (. There was a significant difference in Group 2 between predicted probabilities and observed percentages (. The predicted and observed proportions of complications in the high-risk group were 38% and 13%, respectively. Conclusion. This study used individual predictions of SRC and showed that using TC-coated suture may prevent SRC. This was particularly significant in high-risk patients.

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

    Maffulli Nicola

    2007-12-01

    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

  18. Usefulness of Irradiated Polyglactin 910 (Vicryl Rapide) for Skin Suturing during Surgery for Lateral Ray Polydactyly of the Toes in Children

    Hajime Matsumine, MD, PhD; Masaki Takeuchi, MD, PhD

    2013-01-01

    Background: This study describes the use of a bioabsorbable suture for skin suturing during surgery for lateral ray polydactyly followed by favorable postoperative outcome without the need for postoperative suture removal. Methods: A 5-0 Vicryl Rapide suture was used for skin suturing during surgery for lateral ray polydactyly in 9 children (mean age, 12.4 mo). Children were allowed to walk and bathe 2 weeks after surgery when over-the-suture taping therapy was started. Results: In all cases,...

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

    Cheng Hong Yeo

    2012-01-01

    Full Text Available 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 demonstrated to be more superior, in terms of rate of deep infection, as compared to nonabsorbable suture when used in rotator cuff repair surgery. Both absorbable and nonabsorbable suture had been demonstrated to have similar mechanical properties by several different studies. The case demonstrated that initial presentation of deep infection can be subtle and easily missed by clinicians and leads to further complications.

  20. Lateral intercrural suture in the caucasian nose: Decreased domal divergence angle in endonasal rhinoplasty without delivery

    Berger, Cezar Augusto Sarraf

    2012-01-01

    Full Text Available Introduction: Several techniques can be performed to improve nasal tip definition such as cartilage resection, tip grafts, or sutures. Objective: To evaluate the outcome of lateral intercrural suture at the lower lateral cartilage by endonasal rhinoplasty with a basic technique without delivery in decreasing the angle of domal divergence and improving the nasal tip definition. Method: This prospective study was performed in 64 patients in which a suture was made on the board head of the lower lateral cartilage in the joint between the dome and lateral crus, using polydioxanone (PDS with sharp, curved needle. Results: In all of the cases, better definition of the nasal tip was achieved by intercrural suturing for at least 6 months postoperatively. Conclusion: Lateral intercrural suture of the lower lateral cartilage provides improved nasal tip definition and can be performed by endonasal rhinoplasty without delivery in the Caucasian nose.

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

    McGlone, R; Fleet, T; Durham, S; Hollis, S.

    2001-01-01

    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.

  2. Transcutaneous Serdev Suture For Buttock’s Lift

    Nikolay Serdev

    2012-10-01

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

  3. The BMP ligand Gdf6 prevents differentiation of coronal suture mesenchyme in early cranial development.

    Dawn E Clendenning

    Full Text Available Growth Differentiation Factor-6 (Gdf6 is a member of the Bone Morphogenetic Protein (BMP family of secreted signaling molecules. Previous studies have shown that Gdf6 plays a role in formation of a diverse subset of skeletal joints. In mice, loss of Gdf6 results in fusion of the coronal suture, the intramembranous joint that separates the frontal and parietal bones. Although the role of GDFs in the development of cartilaginous limb joints has been studied, limb joints are developmentally quite distinct from cranial sutures and how Gdf6 controls suture formation has remained unclear. In this study we show that coronal suture fusion in the Gdf6-/- mouse is due to accelerated differentiation of suture mesenchyme, prior to the onset of calvarial ossification. Gdf6 is expressed in the mouse frontal bone primordia from embryonic day (E 10.5 through 12.5. In the Gdf6-/- embryo, the coronal suture fuses prematurely and concurrently with the initiation of osteogenesis in the cranial bones. Alkaline phosphatase (ALP activity and Runx2 expression assays both showed that the suture width is reduced in Gdf6+/- embryos and is completely absent in Gdf6-/- embryos by E12.5. ALP activity is also increased in the suture mesenchyme of Gdf6+/- embryos compared to wild-type. This suggests Gdf6 delays differentiation of the mesenchyme occupying the suture, prior to the onset of ossification. Therefore, although BMPs are known to promote bone formation, Gdf6 plays an inhibitory role to prevent the osteogenic differentiation of the coronal suture mesenchyme.

  4. Single-incision laparoscopic splenectomy with innovative gastric traction suture

    Srikanth G

    2011-01-01

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

  5. An accessory skull suture mimicking a skull fracture.

    Wiedijk, J E F; Soerdjbalie-Maikoe, V; Maat, G J R; Maes, A; van Rijn, R R; de Boer, H H

    2016-03-01

    This paper describes an investigation of the sudden and unexpected death of a five-and-a-half-month-old boy. As in every Dutch case of sudden unexpected death in infancy (SUDI), a multidisciplinary diagnostic approach was used. This included post-mortem radiography, showing a linear discontinuity of the parietal bone. Originally this was interpreted as a skull fracture, but autopsy indicated no signs of mechanical trauma. Instead the defect was defined as a unilateral accessory suture of the parietal bone. The initial erroneous diagnosis had severe adverse consequences and thus every health care professional or forensic specialist dealing with paediatric mechanical traumas should be cautious of this rare anomaly. PMID:26860068

  6. Identification of IGF-I in the calvarial suture of young rats: histochemical analysis of the cranial sagittal sutures in a hyperthyroid rat model.

    Akita, S; Hirano, A; Fujii, T

    1996-01-01

    Premature closure of cranial sutures has been known as one of the complications of juvenile or congenital hyperthyroidism. Thyroid hormone is an anabolic agent for bone formation in the early stages of childhood development. In children, excess thyroid hormone acts as an acceleration factor for the skeletal bone, whereas in adult hyperthyroidism, it causes bone mineral loss due to the high turnover rate of bone formation and consequently bone resorption. In addition, there are numerous literature descriptions concerning the interactions among bone metabolism, hormones, and growth factors, among which insulin-like growth factor I (IGF-I) is the most abundantly found growth factor in osteoblasts and in bone models in vivo. We therefore investigated whether or not the cranial sutures show accelerated closure and how the local growth factors or cytokines participate and function in local bone metabolism after administration of exogenous excess thyroid hormone in a rat model. A total of 60 female Wistar rats, aged 10 days, were divided into two groups, the triiodothyronine (T3)-treated group (n = 30, T3 0.1 microgram/gm of body weight per day) and the control group (n = 30, saline vehicle only), and were maintained and subsequently sacrificed at 15, 30, and 60 days. The parameters of cranial width derived from the morphologic measurements of the skull indicated that the lambda-asterion distance at 30 days and the pterion-bregma distance at 60 days in the T3-treated group were significantly decreased compared with those of the control group. Furthermore, the fluorescent histologic findings showed fluorescent labeling with no interruption along the suture edges, suggesting continuous bone formation, and displayed narrowing of the suture gap of the sagittal suture in the T3-treated group. Tartrate resistant acid phosphatase staining showed very little osteoclastic activity in the sagittal suture, especially in the T3-treated group. The intensity of immunohistochemical

  7. 78 FR 78748 - 2,5-Furandione, polymer With ethenylbenzene, Reaction Products With polyethylene-polypropylene...

    2013-12-27

    ...-polypropylene glycol 2-aminopropyl Me ether; minimum number average molecular weight (in amu), 14,000 (CASRN... absorbing polymer with a number average molecular weight (MW) greater than or equal to 10,000 daltons. 7... polyethylene-polypropylene glycol 2- aminopropyl Me ether; minimum number average molecular weight (in amu),......

  8. Effect of particle size, coupling agent and DDGS additions on Paulownia wood polypropylene composites

    The mechanical, flexural, thermal, and physical characteristics of wood plastic composites employing Paulownia wood (PP) flour derived from 36-mo-old trees blended with polypropylene (PP) were analyzed. Composites of 25% and 40% w/w of PW and 0-10% by weight of maleated polypropylene (MAPP) were pr...

  9. Effect of γ-radiation on trypsin immobilized at a modified polypropylene textile material

    In studying the proteolytic activity and ESR spectra of γ-irradiated samples of trypsin immobilized at an inoculated copolymer of polypropylene with polyacrylic acid it was established that the carrier of a modified polypropylene increase the radioresistances of trypsin immobilized on it

  10. Influence of gamma irradiation on carbon nanotube-reinforced polypropylene.

    Castell, P; Medel, F J; Martinez, M T; Puértolas, J A

    2009-10-01

    Single walled carbon nanotubes (SWNT) have been incorporated into a polypropylene (PP) matrix in different concentrations (range: 0.25-2.5 wt%). The nanotubes were blended with PP particles (approximately 500 microm in size) before mixing in an extruder. Finally, rectangular plates were obtained by compression moulding. PP-SWNT composites were gamma irradiated at different doses, 10 and 20 kGy, to promote crosslinking in the matrix and potentially enhance the interaction between nanotubes and PP. Extensive thermal, structural and mechanical characterization was conducted by means of DSC, X-ray diffraction, Raman spectroscopy, uniaxial tensile tests and dynamic mechanical thermal (DMTA) techniques. DSC thermograms reflected higher crystallinity with increasing nanotube concentration. XRD analysis confirmed the only presence of a monoclinic crystals and proved unambiguously that CNTs generated a preferred orientation. Raman spectroscopy confirmed that the intercalation of the polymer between bundles is favored at low CNTs contents. Elastic modulus results confirmed the reinforcement of the polypropylene matrix with increasing SWNT concentration, although stiffness saturation was observed at the highest concentration. Loss tangent DMTA curves showed three transitions for raw polypropylene. While gamma relaxation remained practically unchanged in all the samples, beta relaxation temperatures showed an increase with increasing CNT content due to the reduced mobility of the system. Gamma-irradiated PP exhibited an increase in the beta relaxation temperature, associated with changes in glass transition due to radiation-induced crosslinking. On the contrary, gamma-irradiated nanocomposites did not show this effect probably due to the reaction of radiative free radicals with CNTs. PMID:19908494

  11. Synthesis and characterization of CNTs using polypropylene waste as precursor

    Bajad, Ganesh S. [Department of Chemical Engineering, Visvesvaraya National Institute of Technology, Nagpur 440010 (India); Tiwari, Saurabh K. [Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076 (India); Vijayakumar, R.P., E-mail: vijayakumarrp@che.vnit.ac.in [Department of Chemical Engineering, Visvesvaraya National Institute of Technology, Nagpur 440010 (India)

    2015-04-15

    Graphical abstract: - Highlights: • A facile method for producing CNTs from polypropylene waste is proposed. • Optimization of Ni/Mo mole ratio using RSM suggests the adequacy of cubic model. • Process parameters were optimized by RSM using Box–Behnken four factorial design. • Maximum desirability of one suggested that 514% of CNTs would yield over Ni{sub 4}Mo{sub 0.2}MgO{sub 1}. • Increase in Ni/Mo ratio from 0.5 to 20, inner diameter of CNTs decreases from 25 to 2 nm. - Abstract: We study the synthesis of MWCNTs using polypropylene waste as a precursor and Ni/Mo/MgO as a catalyst by the combustion technique. Molar ratios of Ni, Mo and MgO in the Ni/Mo/MgO catalyst were optimized using response surface methodology (RSM) to obtain the maximum yield of CNTs. The mole ratio 4/0.2/1 was found to yield more carbon product. Further, process parameters such as combustion temperature, combustion time, polymer and catalyst weight were optimized by RSM using Box–Behnken three-level and four-factorial design. The best possible combination of process parameters (combustion time of 10 min, combustion temperature of 800 °C, polymer weight of 5 g and catalyst weight of 150 mg) for maximum yield of CNTs was obtained. HRTEM indicates that the diameter of CNTs depends on the catalyst composition used for the synthesis of CNTs. The results of the study indicate a facile method for producing CNTs from polypropylene waste.

  12. Conversion of atactic polypropylene waste to fuel oil. Final report

    Bhatia, J.

    1981-04-01

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

  13. Improvement in compatibility and mechanical properties of modified wood fiber/polypropylene composites

    2008-01-01

    To improve the interfacial compatibility between wood fibers and polypropylene and the toughness of wood-fiber/polypropylene composites,maleic anhydride grafted polypropylene (PP-g-MAH) and maleic anhydride grafted styrene-ethylene-butadiene-styrene copolymers (SEBS-g-MAH) were used as modifiers.Mechanical properties of wood-fiber/polypropylene (WF/PP) composites were improved when PP-g-MAH or SEBS-g-MAH was added.When either of these copolymers was added,the composites had better interfacial compatibility than the unmodified composite.This was verified by scanning electron microscope (SEM) observations and dynamic mechanical analysis (DMA).The mechanical properties of the composites were significantly improved because of the good interfacial bonding between wood fibers and polypropylene when PP-g-MAH and SEBS-g-MAH were added.

  14. Grafting polymerization of styrene onto preirradiated polypropylene fabric

    The grafting copolymerization of styrene onto polypropylene (PP) fabric has been studied by the preirradiation of gamma rays and electron beam, respectively. The PP fabric samples wee irradiated in the air and nitrogen gas individually. The effects of absorbed dose, styrene concentration in methanol, reaction temperature and reaction time on the degree of grafting were studied. Effects of storage time and temperature on the grafting rate were also observed. And a comparison of γ-ray and EB irradiation has been made. The results were reasonably interpreted by assuming that the grafting reaction was predominately initiated by trapped radicals

  15. Dependence of morphology and crystallization parameters of polypropylene on nucleation

    Janevski, Aco; Bogoeva-Gaceva, Gordana

    2014-01-01

    The rate of crystallization of isotactic polypropylene (iPP) at a given temperature, likewise the other crystallizing polymers, depends on the number of active centers from which the crystal growth begins, i.e. on the density of nuclei. In this paper the nucleation characteristics of some additives and reinforcements for iPP, which are mainly applied in the manufacturing of iPP based composites, have been investigated. The glass fibers, incorporated in the polymer in amount of 30-50 wt %, are...

  16. Casting thin films of cellulose nitrate, polycarbonate, and polypropylene

    Plastic films of cellulose nitrate (collodion), polycarbonate (LexanTM), and polypropylene have many uses in the production of nuclear targets, as well as in other research areas. The uses and properties of these films are summarized, and techniques for producing them by casting onto glass and other surfaces in controlled thicknesses are described. Special apparatus and precautions for producing such films in the thickness range from 0.04 μm to 10 μm, and in sizes up to 100 mmx125 mm have been developed. (orig.)

  17. INTERACTION BETWEEN THE SURFACE GLYCOSYLATED POLYPROPYLENE MEMBRANE AND LECTIN

    Qian Yang; Ling-shu Wan; Zhi-kang Xu

    2008-01-01

    A glycopolymer bearing glucose residues was tethered onto the surface of polypropylene microporous membrane by UV-induced graft polymerization of α-allyl glucoside. Concanavalin A (Con A), a glucose recognizing lectin, could be specifically adsorbed to the membrane surface. On the other hand, the membrane surface showed no recognition ability to another lectin peanut agglutinin. Moreover, the recognition complex between the glycosylated membrane surface and Con Acould be inhibited by glucose and mannose solution. This surface glycosylated membrane could be used as affinity membrane for protein separation and purification.

  18. Morphology-mechanical Property Relationship of Polypropylene/starch Blends

    C.H. Azhari; Wong, S F

    2001-01-01

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

  19. STUDY OF ACOUSTIC EMISSION DURING NON- ISOTHERMAL CRYSTALLIZATION OF POLYPROPYLENE

    SHEN Jingshu; XU Duanfu; YAO Ruigang; LIU Ruixia; LI Dawei

    1990-01-01

    In this paper we have presented the results of acoustic emission (AE) during non-isothemal crystallization of polypropylene (PP) melt with mean cooling rate 4 ℃ /min , and discussed the effects of molecular weight (MW) on AE activity. It is shown that the amount of AE ring-down counts during whole crystallization of PP depends on the MW strongly. The copious AE bursts have been observed at the late stage of PPcrystallization.AE bursts are caused by cracking ,crazing and cavitation between spherulites and inside spherulites.

  20. Toughening wood/polypropylene composites with polyethylene octene elastomer (POE)

    JIANG Feng; QIN Te-fu

    2006-01-01

    Polyethylene octene elastomer (POE) as impact modifier was incorporated into wood/polypropylene composites (WPC) to enhance the impact strength of the composite. Two extruding routes, i.e. direct extruding route and two-stage extruding route, were adopted to produce Wood Powder/PP/POE ternary composites. The mechanical and dynamic mechanical analysis (DMA) properties of the composites were investigated. The results showed that the addition of POE can increase the impact strength of the composites, and the composites produced via two-stage extruding route showed superior mechanical properties. The results of the DMA confirmed the mechanical tests.

  1. Packing parameters effect on injection molding of polypropylene nanostructured surfaces

    Calaon, Matteo; Tosello, Guido; Hansen, Hans Nørgaard;

    2012-01-01

    In today´s industry, applications involving surface patterning of sub-μm to nanometer scale structures have shown a high growth potential. To investigate the injection molding capability of replicating sub-μm surface texture on a large scale area, a 30x80 mm2 tool insert with surface structures...... having a diameter of 500 nm was employed. The tool insert surface was produced using chemical-based-batch techniques such aluminum anodization and nickel electroplating. During the injection molding process, polypropylene (PP) was employed as material and packing phase parameters (packing time, packing...

  2. Polypropylene-polyethylene blends modified by gamma radiation

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

  3. Rheological Behavior for Mica-filled Polypropylene Composite Melts

    Yan Xia CAO; Miao DU; Qiang ZHENG

    2004-01-01

    The study on rheological properties of a series of mica-filled polypropylene ( PP ) composites was carried out. The influence of surface-treatment of mica particles on dynamic rheological behavior of the composites were dealt with. The viscosity ( η ) and dynamic modulus ( G′ ) of the composite melts were higher than those of PP matrix, especially those for systems treated with silane, which was attributed to the interfacial adhesion enhancement. However, surface-treatment of mica by titanate resulted in lower η and G′, as compared with the treatment by silane. The reason for this is believed to be the formation of the mono-molecular layer on the mica surface.

  4. Supermolecular structure changes in polypropylene filled with Au nanoparticles

    Šlouf, Miroslav; Kratochvíl, Jaroslav; Baldrian, Josef; Pavlova, Ewa; Hromádková, Jiřina; Masirek, R.; Piorkowska, E.

    Rio de Janeiro : International Union of Pure and Applied Chemistry , 2006, s. 1-2. [World Polymer Congress Macro 2006 /41./. Rio de Janeiro (BR), 16.07.2006-21.07.2006] R&D Projects: GA ČR GA106/04/1118; GA ČR GA203/04/0688 Grant ostatní: Ministry of Education and Science(PL) 3T08E 059 29 Institutional research plan: CEZ:AV0Z40500505 Keywords : Au nanoparticles * polypropylene * super-molecular structure Subject RIV: CD - Macromolecular Chemistry

  5. Rheological behaviour of polypropylene blends utilized in foaming process

    Piyamanocha, P.; Sedláček, T.; Polášková, M.; Filip, Petr; Sáha, P.

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

  6. Characterization of Fibers Produced from Blends of Polybutylene and Polypropylene

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

    2007-01-01

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

  7. Introduction of a New Suture Method in Repair of Peripheral Nerves Injured with a Sharp Mechanism

    Alireza Saied

    2015-09-01

    Full Text Available Background: The standard method for repair of an injured peripheal nerve is epineural repair with separate sutures. Herein we describe a method in which the nerve is sutured with continous sutures. In fact this method has not been utilized for nerve repair previously and our purpose was to compare it to the standard method. If it proved to be successful it would replace the standard method in certain circumstances. Methods: The proposal of the clinical trial was given a reference number form the ethics comitee. 25 dogs in which the scaitic nerve was cut by a sharp blade under genaeral anesthesia were divided randomly into three groups: control (5 dogs, repair of sciatic nerve with simple sutures (10 and repair with continous sutures (10. In the control group the nerve was not repaired at all. After 6 weeks the dogs were killed and the nerve was studied by light and electronic microscopes. The amount of consumed suture material, time of repair, myelin thickness and axon diiameter were examined. Ultrastructural studies were performed to assess degeneration and regeneration findings. Results: Time of repair and the amount of consumed suture material were significantly lower in the continous group (P

  8. Comparison of polydioxanone (PDS and polyamid (nylon sutures complications in abdominal midline repair (laparotomy surgery

    F.Eshghi

    2006-01-01

    Full Text Available Background and purpose: Despite progresss in the techniques of surgery, there is still a lot of controversy about selection of the best technique and suture material. Many post operation complications such as infection, wound dehiscence, pain and sinus formation are related to the type of the suture used. In this study we compared the complications due to the absorbent suture (PDS with a non absorbent suture (nylon in laparotomy operation.Materials and Methods: This clinical trial was performed on 120 patients referring to Imam Khomeini hospital, Sari, 2003-2005 for laparotomy. They were randomly divided in tow groups of equal number. The incision was repaired with PDS sutures in case and with nylon suture in control group. All patients under study were followed up for one year. Data about chronic pain,wound dehiscence, infection, hernia and sinus formation were recorded and analyzed using SPSS software and Chi- square test.Results: In this study 120 patients (60 in case and 60 in control groups were enrolled. After laparotomy, the incidence of chronic pain and sinus formation in case group was significantly less than the control group. There were no significant differences between the rate of infection, hernia and wound dehiscence in the two groups.Conclusion: No significant differences in the rate of infection, hernia and wound dehiscence between two types of suture materials were observed. However, application of PDS leads to less pain and sinus formation. Therefore, it can be a better choice in surgical incisions.

  9. Enhanced Zone II Flexor Tendon Repair through a New Half Hitch Loop Suture Configuration

    Thomopoulos, Stavros; Gelberman, Richard H.

    2016-01-01

    This study evaluated the impact of a new half hitch loop suture configuration on flexor tendon repair mechanics. Cadaver canine flexor digitorum profundus tendons were repaired with 4- or 8-strands, 4–0 or 3–0 suture, with and without half hitch loops. An additional group underwent repair with half hitch loops but without the terminal knot. Half hitch loops improved the strength of 8-strand repairs by 21% when 4–0, and 33% when 3–0 suture was used, and caused a shift in failure mode from suture pullout to suture breakage. 8-strand repairs with half hitch loops but without a terminal knot produced equivalent mechanical properties to those without half hitch loops but with a terminal knot. 4-strand repairs were limited by the strength of the suture in all groups and, as a result, the presence of half hitch loops did not alter the mechanical properties. Overall, half hitch loops improved repair mechanics, allowing failure strength to reach the full capability of suture strength. Improving the mechanical properties of flexor tendon repair with half hitch loops has the potential to reduce the postoperative risk of gap formation and catastrophic rupture in the early postoperative period. PMID:27101409

  10. Effectiveness of ultrasonographic evaluation of the cranial sutures in children with suspected craniosynostosis

    Simanovsky, Natalia; Hiller, Nurith; Koplewitz, Benjamin; Rozovsky, Katya [Hadassah Hebrew University Medical Center, Department of Medical Imaging, Mount, Scopus, P.O. Box 24035, Jerusalem (Israel)

    2009-03-15

    Computed tomography (CT) is the 'gold standard' for evaluation of the cranial sutures. While prenatal cranial suture evaluation with ultrasound (US) is common, US has not been established as a postnatal screening tool. We evaluated the effectiveness of US for diagnosis of craniosynostosis (CS). During 2006, 24 infants with questionable CS were assessed with US of the sagittal, metopic, and bilateral coronal and lambdoid sutures. US findings and clinical records were reviewed retrospectively. Sixteen boys and eight girls (ages 1-11 months, mean 4.3) underwent US. The correct diagnosis was provided in 23 (95%), with equivocal findings in one patient. Cranial sutures appeared normal in 15 infants, who had normal clinical presentation at mean 5.8 months follow-up; CT confirmation was obtained in two. In eight children, US identified premature closure of one or more cranial sutures. Three-dimensional CT was performed as a preparation for surgery in four, with classical CS findings. In one case with inconclusive US findings, CT showed narrow but open sutures. Sonographic examination of cranial sutures may serve as a first imaging tool for evaluation of craniosynostosis. CT may be reserved for children with abnormal or equivocal ultrasound and for preoperative planning. (orig.)

  11. Ameloblastin inhibits cranial suture closure by modulating MSX2 expression and proliferation.

    Phimon Atsawasuwan

    Full Text Available Deformities of cranial sutures such as craniosynostosis and enlarged parietal foramina greatly impact human development and quality of life. Here we have examined the role of the extracellular matrix protein ameloblastin (Ambn, a recent addition to the family of non-collagenous extracellular bone matrix proteins, in craniofacial bone development and suture formation. Using RT-PCR, western blot and immunohistochemistry, Ambn was localized in mouse calvarial bone and adjacent condensed mesenchyme. Five-fold Ambn overexpression in a K14-driven transgenic mouse model resulted in delayed posterior frontal suture fusion and incomplete suture closure. Moreover, Ambn overexpressor skulls weighed 13.2% less, their interfrontal bones were 35.3% thinner, and the width between frontal bones plus interfrontal suture was 14.3% wider. Ambn overexpressing mice also featured reduced cell proliferation in suture blastemas and in mesenchymal cells from posterior frontal sutures. There was a more than 2-fold reduction of Msx2 in Ambn overexpressing calvariae and suture mesenchymal cells, and this effect was inversely proportionate to the level of Ambn overexpression in different cell lines. The reduction of Msx2 expression as a result of Ambn overexpression was further enhanced in the presence of the MEK/ERK pathway inhibitor O126. Finally, Ambn overexpression significantly reduced Msx2 down-stream target gene expression levels, including osteogenic transcription factors Runx2 and Osx, the bone matrix proteins Ibsp, ColI, Ocn and Opn, and the cell cycle-related gene CcnD1. Together, these data suggest that Ambn plays a crucial role in the regulation of cranial bone growth and suture closure via Msx 2 suppression and proliferation inhibition.

  12. New Method of Age Estimation from Maxillary Sutures Closure in a Thai Population.

    Sinthubua, A; Theera-Umpon, N; Auephanwiriyakul, S; Ruengdit, S; Das, S; Mahakkanukrauh, P

    2016-01-01

    Age estimation is one of the major components of forensic identification. Cranial suture closure has long been used as indicator for age estimation. Maxillary sutures have been less studied for estimation of age at death because they vary in their timing of closure with age. The purpose of this study was to estimate age by examining 190 Thai skulls with age ranging between 15-93 years from Forensic Osteology Research Center, Faculty of Medicine, and Chiang Mai University. Four parts of maxillary suture (incisive, anterior, transverse, and posterior sutures) were investigated the suture obliteration of each suture by computerizing from photograph. The suture were measured by pixel counting.The prediction model which based on the support vector machine (SVM) for regression or support vector regression (SVR) was utilized for data analysis. The results showed high correlation (R2 = 0.9086) between the predicted age and actual age. Plot between actual age group and predicted age in seven groups also revealed high correlation (R2 = 0.9434). These can be implied that we are able to use this SVR model to predict age at death using maxillary suture information.The interesting issue is to further apply this model in more cases to ensure the generalization of the finding. This study is the first attempt to estimate age at death using a new method based on novel analysis which considers a characteristic of relationship between maxillary suture closures with age that are not in linear form. The present study may contribute as a basis knowledge and method for further study of age estimation in archaeological and forensic anthropological contexts, especially when only skull or base of skull are found. PMID:27212570

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

    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

  14. Dose equivalent quantities in the ICRU tissue sphere for 0.4-10.0 MeV neutrons

    The effect of the fluctuations of the cross sections in the energy range from 0.4-10.0 MeV on the responses of neutrons in the ICRU standard tissue sphere is investigated. The point energy Monte Carlo method was used for the estimation of the dose equivalent and the absorbed dose. A new approach was adopted where band-averaged responses were calculated instead of the previous approach which generates them as point values. The need for interpolation of the fluence-to-dose conversion factors between the point values is this eliminated. Based on the depth-dose distributions in the standard sphere, the index quantities, the newly-defined operational quantities and the effective quality factors were evaluated. The differences between the calculated indices and the previous results varied from -13% to +4% for the deep dose equivalent, and from -19% to +7% for the shallow dose equivalent. The energy dependencies of the responses were dominated by the oxygen content in tissue due to both the resonant oxygen cross section and the characteristic behavior of the proton quality factors

  15. The Effect of Tissue Culture on Suture Holding Strength and Degradation in Canine Tendon

    H. Omae; Zhao, C.; Sun, Y.-L.; Zobitz, M. E.; Moran, S. L.; Amadio, P. C.

    2009-01-01

    The purpose of this study was to assess tendon metabolism and suture pull-out strength after simple tendon suture in a tissue culture model. One hundred and twelve flexor digitorum profundus tendons from 28 dogs were cultured for 7, 14, or 21 days with or without a static tensile load. In both groups increased levels of matrix metalloproteinase (MMP) mRNA was noted. Suture pull-out strength did not decrease during tissue culture. While the presence of a static load had no effect on the pull-o...

  16. Iatrogenic Ulnar Nerve Injury post Laceration Suturing – An Unusual Presentation

    Murali Mothilal; Mothilal S N; Ravichandran S; Jamal Mohammad

    2013-01-01

    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 scre...

  17. Brief communication: age and fractal dimensions of human sagittal and coronal sutures

    Lynnerup, Niels; Jacobsen, Jens Christian Brings

    2003-01-01

    The fractal dimensions of human sagittal and coronal sutures were calculated on 31 complete skulls from the Terry Collection. The aim was to investigate whether the fractal dimension, relying on the whole sutural length, might yield a better description of age-related changes in sutural morphology......, as opposed to other methods of quantification, which generally rely on more arbitrary scoring systems. However, the fractal dimension did not yield better age correlations than other previously described methods. At best, the results reflected the general observation that young adults below age 40...

  18. Acoustic properties of polypropylene composites reinforced with stone groundwood

    Joan Pere López

    2012-11-01

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

  19. The influence of antioxidant on positron annihilation in polypropylene

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

  20. Phenolic rigid organic filler/isotactic polypropylene composites. I. Preparation

    Dongming QI; Lei YANG; Minghua WU; Heming LIN; Kohhei NITTA

    2008-01-01

    A novel phenolic rigid organic filler (KT) was melt-mixed with an isotactic polypropylene (iPP) to pre-pare a series of PP/KT composites,with or without maleic anhydride grafted polypropylene (MAPP)/as compatili-zer.The evolution of filler morphology during melt-mix-ing and melt-pressure processes was monitored by scanning electron microscope (SEM) and polarized optical microscope (POM).The influences of shear force,pressure time,filler content and MAPP concentration on the final filler dispersion were studied.We found that this rigid organic filler readily melted and dispersed homoge-nously into the iPP matrix through a fission-fusion pro-cess during the melt-mixing process.Thus a balanced dispersion,which was closely related to shear force and MAPP concentration,can be achieved.During the melt-pressure process,parts of the filler particles combined gradually through a coalescence process.However,the incorporation of MAPP can effectively inhibit the tend-ency to coalesce and refine the filler particles sizes into nanoscale.Thus,a series of PP/KT composites with con-trollable filler particles size and narrow size distribution can be obtained just by adjusting process conditions and MAPP concentration.In addition,due to the in-situ formation mechanism,the filler phase possessed a typical solid true-spherical shape.

  1. Dielectric Relaxations in Polypropylene-Polyamide Compatibilized Blends

    Laredo, Estrella; Grimau, Mario; Sánchez, Freddy; Bello, Alfredo; Gómez, Marian; Marco, Carlos

    2003-03-01

    The dielectric relaxations in semicrystalline nylon-6,PA, and its blends with polypropylene, and polypropylene grafted with maleic anhydride are studied by broad band dielectric spectroscopy (BBDS) (10-2temperatures from 133 to 433 K. The BBDS spectrum consists for the homopolymer and the blends of low temperature relaxations γ and β, which intensities vary oppositely with the water level. At higher temperatures the α relaxation is on the high temperature tail of a frequency independent peak which disappears as the sample is dryed. This peak is associated to the existence of a phase transition occurring in the water clusters present in these samples. The glass transition mode presents important differences if observed during the experimental run taken with increasing temperatures (wet sample) or during the runs recorded while the temperature decreases(dry samples). As the water content in the material is changing during the temperature sweep, the initially water plasticized material is rigidized by the drying procedure and a new α peak appears at higher temperature which corresponds to the Tg of the dry PA. At still higher temperatures there is an additional relaxation, α ^', probably associated to chain motions in the crystalline phase. The precise determination of the relaxation parameters for the different modes is presented.

  2. THERMOCHROMIC EFFECTS OF LEUCO DYES STUDIED IN POLYPROPYLENE

    Arno Seeboth; Detlef L(o)tzsch; Elvira Potechius; Renate Vetter

    2006-01-01

    A series of thermochromic polypropylene foils were prepared by embedding various leuco dye-developer-solvent systems in the polymer matrix. Bisphenol A, laurylgallate, ethylgallate and p-hydroxybenzoic acid methyl ester were used as developers, crystal violet lactone and 3,3-bis-(1-n-butyl-2-methyl-3-indolyl)-phthalide as dyes and 1-octanoic acid methyl ester as solvent. The molar ratio between the three components of the investigated leuco dye-developer-solvent systems was kept constant. All obtained polypropylene foils exhibit an excellent thermochromic behavior. The foils, prepared by extrusion technology, switch from color to colorless with increasing temperature. The influence of molecular structure of the developer on the intensity of the colored state and the influence of a developer-surfactant complex on the resulting thermochromic properties were investigated. The results are presented and discussed in detail according to a molecular model suggesting that the ring-opening process of the leuco dye is triggered by the formation of dye-developer complexes via H-bondings.

  3. INTERFACE REACTION BETWEEN γ- AMINOPROPYLTRIMETHOXYSILANE AND ULTRAVIOLET IRRADIATED POLYPROPYLENE

    2000-01-01

    The interface reaction between ultraviolet irradiated polypropylene(UV-PP) and an amino silane coupling agent, γ-aminopropyltrimethoxysilane (γ-APS) adsorbed on glass fibers has been investigated by means of the combining use of solvent extraction and FTIR as well as XPS. First, polypropylene (PP) physisorbed on the glass fibers surface was removed by the solvent extraction in order to minimize the effect of the PP siginal in FTIR and XPS analyses. Second, the remaining glass fibers after solvent extraction were analyzed by FTIR and XPS. The results show that the absorption bands of PP still exist in the FTIR spectrum and two new bands of N1s at 399.1eV and 401.6eV appear in the XPS spectrum for the composite with UV-PP and γ-APS treated glass fibers. Thus, the interface reaction between the UV-PP and γ-APS has been monitored directly. In addition, it may be concluded that OH and COOH groups of UV-PP form chemical bonds with NH2 group of γ-APS , respectively.

  4. Reinforcement of Recycled Foamed Asphalt Using Short Polypropylene Fibers

    Yongjoo Kim

    2013-01-01

    Full Text Available This paper presents the reinforcing effects of the inclusion of short polypropylene fibers on recycled foamed asphalt (RFA mixture. Short polypropylene fibers of 10 mm length with a 0.15% by weight mixing ratio of the fiber to the asphalt binder were used. The Marshall stability test, the indirect tensile strength test, the resilient modulus test, and wheel tracking test of the RFA mixtures were conducted. The test results were compared to find out the reinforcing effects of the inclusion of the fiber and the other mixtures, which included the conventional recycled foamed asphalt (RFA mixtures; the cement reinforced recycled foamed asphalt (CRFA mixtures; the semihot recycled foamed asphalt (SRFA mixtures; and recycled hot-mix asphalt (RHMA mixtures. It is found that the FRFA mixture shows higher Marshall stability than the RFA and SRFA mixtures, higher indirect tensile strength than the RFA mixture, and higher rut resistance than the RFA, SRFA, and RHMA mixtures as seen from the wheel tracking test.

  5. Photodegradation of a polypropylene filled with lanthanide complexes

    Valérie Massardier

    2015-01-01

    Full Text Available Abstract This research aims at studying the photodegradation of a polypropylene formulation filled with lanthanide complexes. These complexes can be used as tracers for the identification of polymer materials in order to facilitate an high speed automatic sorting of plastic wastes for an economically efficient recycling. By paying attention to the evolution of carbonyl absorption bands in FTIR spectra, it is observed that the addition of lanthanide complexes into our formulation improves UV stability of polypropylene by reducing the extent of photo-degradation. Furthermore, TG analyses show that the traced blends can maintain better thermal properties, after irradiation. A significant increase of the crystallinity degree and a decrease of the melting temperature are more pronounced for the unfilled UV–irradiated PP. This might result from chemi-crystallization that can occur when chain entanglements are broken as a result of chain scissions. From SEM analyses, it is observed that the severity of surface cracks induced by photo degradation is reduced for filled PP. The mechanical tests are in agreement with this result and show a fundamental change in the behavior of the as-exposed blends from a ductile to a brittle material.

  6. Morphology and properties of recycled polypropylene/bamboo fibers composites

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

  7. TIME-DEPENDENT MORPHOLOGY OF POLYETHYLENE-POLYPROPYLENE BLENDS

    Jun Li; Robert A.Shanks; Long Yu

    2002-01-01

    The effect of time-temperature treatment on morphology of polyethylene-polypropylene (PE-PP) blends wasstudied to establish a relationship between thermal history, morphology and mechanical properties. Polypropylene (PP)homopolymers were used to blend with various polyethylenes (PE), including high density polyethylene (HDPE), lowdensity polyethylene (LDPE), linear low density polyethylene (LLDPE), and very and ultra low density polyethylene(VLDPE and ULDPE). The majority of the blends were prepared at a ratio ofPE:PP = 80:20, while blends of PP and LLDPEwere prepared at various compositions. Thermal treatment was carried out at temperatures between the crystallizationtemperatures of PP and PEs to allow PP to crystallize first from the blends. On cooling further, PE crystallized too. A verydiffuse PP spherulite morphology in the PE matrix was formed in some partially miscible blends when PP was less than 20%by mass. Droplet-matrix structures were developed in other blends with either PP or PE as dispersed domains in a continuousmatrix, depending on the composition ratio. The scanning electron microscopy (SEM) images displayed a fibrillar structureof PP spherulite in the LLDPE-PP (80:20) and large droplets of PP in the HDPE-PP (80:20) blend, providing larger surfacearea and better bonding in the LLDPE-PP (80:20) blends. This explains why the blends with diffuse spherulite morphologyshowed greater improvement in tensile properties than droplet-matrix morphology blends after time-temperature treatment.

  8. SURFACE MODIFICATION OF POLYPROPYLENE MICROPOROUS MEMBRANE BY TETHERING POLYPEPTIDES

    Zhen-mei Liu; Zhi-kang Xu; Mathias Ulbricht

    2006-01-01

    Two kinds of polypeptides were tethered onto the surface of polypropylene microporous membrane (PPMM)through a ring opening polymerization of L-glutamate N-carboxyanhydride initiated by amino groups which were introduced by ammonia plasma and γ-aminopropyl triethanoxysilane treatments. X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (FT-IR/ATR), scanning electron microscopy (SEM), together with water contact angle measurements were used to characterize the modified membranes. XPS analyses and FT-IR/ATR spectra demonstrated that polypeptides are actually grafted onto the membrane surface. The wettability of the membrane surface increases at first and then decreases with the increase in grafting degrees of polypeptide. Platelet adhesion and murine macrophage attachment experiments reveal an enhanced hemocompatibility for the polypeptide modified PPMMs. All these results give evidence that polypeptide grafting can simultaneously improve the hemocompatibility as well as reserve the hydrophobicity for the membrane, which will provide a potential approach to improve the performance of polypropylene hollow fiber microporous membrane used in artificial oxygenator.

  9. An alternative tectonic model for the Yarlung Zangbo suture zone

    2010-01-01

    The new field investigations along the Yarlung Zangbo ophiolites zone show that these series underwent low green-schist metamorphism and were then fractured and occurred as slabs in tectonic melanges,without regional tectonic polarity.No large shear zone in north-south direction has been identified between ophiolite bodies and flysch layers on both side and a conformable contact relationship can be observed locally between them.A great mass of tectonic mélange has been substantiated as submarine olistolith bodies.The Mesozoic sedimentary facies and its evolution in both north and south of the ophiolite zone are corresponding in time.The ophiolite zone has often been divided into parallel branches,separated by narrow flysch slats.There is also a similarity of the Paleozoic and the basement of the High Himalaya,Lhasa and Qiangtang Terranes,and they are distinctly different from those of the Indian continent.The geologic information does not warrant a postulate that the Himalaya and Tibet were once separated by a great ocean;it is therefore consistent with an alternative tectonic model by back-arc basin collapse with its juvenile narrow oceanic crust.The real plate tectonic suture,the Neotethys might be covered under the Miocene Siwalik molasse in the southern slope of the High Himalaya range.Based on the new model,the Neotethyan ocean floor was subducted beneath the Asia since the Late Triassic.The outer continental margin of Eurasia was split from the Lhasa Terrane so that a back-arc basin came into existence.Hemi-pelagic and deep sea sediments were deposited before the Late Cretaceous flysch sedimentation,with the linear juvenile oceanic crust when back-arc volcanism occurred in the Gandese region.The Yarlung Zangbo back-arc basin was eventually eliminated when the High Himalayas were sutured onto Eurasia.The ocean floor lightly underthrusted to north and south sides,sediments of the basin were deformed as fold-thrusting.The Neotethys was eliminated during the

  10. 77 FR 8117 - Medical Devices; Cardiovascular Devices; Classification of the Endovascular Suturing System

    2012-02-14

    ... Testing Incompatibility with endograft Bench testing Migration or fracture of the endovascular Bench testing suture. Animal testing Clinical evaluation Imaging Incompatibility Bench testing Labeling... Testing Labeling Corrosion Bench testing Improper deployment or inability to deploy.. Bench testing...

  11. Radiation-induced grafting of acrylic acid onto polypropylene film and its biodegradability

    Mandal, Dev K.; Bhunia, Haripada; Bajpai, Pramod K.; Chaudhari, C. V.; Dubey, K. A.; Varshney, L.

    2016-06-01

    Polypropylene based commodity polyolefins are widely used in packaging, manufacturing, electrical, pharmaceutical and other applications. The aim of the present work is to study the effect of grafting of acrylic acid on the biodegradability of acrylic acid grafted polypropylene. The effect of different conditions showed that grafting percentage increased with increase in monomer concentration, radiation dose and inhibitor concentration but decreased with increase in radiation dose rate. The maximum grafting of 159.4% could be achieved at optimum conditions. The structure of grafted polypropylene films at different degree of grafting was characterized by EDS, FTIR, TGA, DSC, SEM and XRD. EDS studies showed that the increase in acrylic acid grafting percentage increased the hydrophilicity of the grafted films. FTIR studies indicated the presence of acrylic acid on the surface of polypropylene film. TGA studies revealed that thermal stability decreased with increase in grafting percentage. DSC studies showed that melting temperature and crystallinity of the grafted polypropylene films lower than polypropylene film. SEM studies indicated that increase in acrylic acid grafting percentage increased the wrinkles in the grafted films. The maximum biodegradability could be achieved to 6.85% for 90.5% grafting. This suggested that microorganisms present in the compost could biodegrade acrylic acid grafted polypropylene.

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

    Joan P. López,

    2012-06-01

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

  13. Effects of surface modification of talc on mechanical properties of polypropylene/talc composites

    Liu, Keyan; Stadlbauer, Wolfgang; Zitzenbacher, Gernot; Paulik, Christian; Burgstaller, Christoph

    2016-03-01

    Low compatibility of polymer matrix and dispersed filler negatively affects the performance of polymeric composites. In order to improve the adhesion between the components in a compound the polymer matrix or/and the filler particles should be modified with a compatibilizer or/and a coupling agent. An overview of our current research on the effect of the addition of silane treated and untreated talc powders on the mechanical properties of polypropylene/talc composites is presented in this paper. Different silane coupling agents (3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane) were used to improve the adhesion at the surface of talc powders. Maleic anhydride grafted polypropylene was utilized to increase the adhesion between the polypropylene matrix and talc powders. The content of maleic anhydride grafted polypropylene (MA-g-PP) was varied between 1 and 5 wt% in polypropylene/talc composites. The surface modification of talc powders has a significant effect on the interfacial structure and the mechanical properties such as tensile strength and impact strength of polypropylene/talc composites. The experiments show that polypropylene grafted with maleic anhydride together with silane surface treatment exhibits the highest potential for improvements in this field.

  14. Research on Static Triaxial Mechanical Properties of New CementSoil Reinforced with Polypropylene Fiber

    Qiang Wang

    2014-01-01

    Full Text Available Through the laboratory test, the mechanical properties of cementsoil with adding desulfurization gypsum, fly ash, and polypropylene fiber were studied. Three different percentages (0%, 0.5%, and 1.0% of polypropylene fiber were mixed into new cementsoil for which the cement content is 15% of the dry soil weight, the desulfurization gypsum content is 2% of the dry soil weight, and the fly ash content is 1.0% of the dry soil weight. The new cementsoil strength reinforced with polypropylene fiber was studied by triaxial test under different polypropylene fiber mixing ratio, different age, and different confining pressure. The experimental results show that, compared with ordinary soil, the deviatoric stress and the peak shear strength reinforced with polypropylene fiber have different amplitude increase. At the same time, the internal friction angle of new cementsoil with polypropylene fiber increases slightly with the growth of the age. The stress-strain curve of the polypropylene fiber cementsoil has the typical work hardening characteristic and has the characteristics of bulge fracture.

  15. Comparisons of the suture zones along a geotraverse from the Scythian Platform to the Arabian Platform

    Ali Yılmaz; Shota Adamia; Hüseyin Yılmaz

    2014-01-01

    The area from the Greater Caucasus to the southeast Turkey is characterized and shaped by several major continental blocks. These are Scythian Platform, PontianeTranscaucasus Continent-Arc System (PTCAS), the AnatolianeIranian and the Arabian Platforms. The aim of this paper is to define these continental blocks and describe and also compare their boundary relationships along the suture zones. The Scythian Platform displays the evidence of the Hercynian and Alpine orogens. This platform is separated from the PTCAS by the Greater Caucasus Suture Zone. The incipient collision began along this suture zone before middleelate Carboniferous whereas the final collision occurred before Oligocene. The PTCAS can be divided into four structural units:(1) the Georgian Block e northern part of the PontianeTranscaucasian island-arc, (2) the southern and eastern Black Sea CoasteAdjaraeTrialeti Unit, (3) the ArtvineBolnisi Unit, comprising the northern part of the southern Transcaucasus, and (4) the Imbricated BayburteGarabagh Unit. The PTCAS could be separated from the AnatolianeIranian Platform by the North AnatolianeLesser Caucasus Suture (NALCS) zone. The initial collision was developed in this suture zone during Senonianeearly Eocene and final collision before middle Eocene or OligoceneeMiocene. The AnatolianeIranian Platform (AIP) is made up of the Tauride Platform and its metamorphic equivalents together with Iranian Platform. It could be separated from the Arabian Platform by the Southeastern Anatolian Suture (SEAS) zone. The collision ended before late Miocene along this suture zone. The southernmost continental block of the geotraverse is the Arabian Platform, which constitutes the northern part of the ArabianeAfrican Plate. This platform includes a sequence from the Precambrian felsic volcanic and clastic rocks to the Campanianeearly Maastrichtian flyschoidal clastics. All the suture zones include MORB and SSZ-types ophiolites in different ages. However, the ages of the

  16. A Study of the Kunlun-Qilian-Qinling Suture System

    2001-01-01

    The Late Neoproterozoic-Early Palaeozoic suture zones within theCentral Orogenic Belt of China can be considered a system-the Kunlun-Qilian-Qinling suture system (KQQ suture system). It is basically divided into the western, central and eastern sectors. The western sector consists of the Küda-Subashi suture zone, the Mazar Kangxiwar suture and the central West Kunlun microblock. The central sector covers the following five suture zones: the Altun, North Qilian, Qaidam northern marginal, Qimantag-Wutuo and East Kunlun southern marginal sutures, in addition to some microblocks such as the mid-south Qilian, Qaidam, Ayakkum and Maqen microblocks. The eastern sector is composed of the Shangdan suture zone, Mianlüe suture zone and central Qinling-Dabie microblock. The KQQ suture system experienced (1) extending-rifting of the Rodinia super-continent in the early-middle Sinian (~780-600 Ma); (2) the formation and evolution of the KQQ archipelagic ocean during the Late Sinian-Ordovician (~600-440 Ma), and (3) closing of the KQQ ocean and forming of the KQQ suture system during the Late Ordovician-early Silurian (~440-400 Ma). As a system comprising many suture zones and microblocks, the KQQ suture system consti tutes the foundation of the Central Orogenic Belt of China.CLC Number:P5 Document ID:Afoundation Item:This study was supported by the National Natural Science Foundation of China (grants 49872077 and 49572153), and the Lu Jiaxi Foundation of the Chinese Academy of Sciences.Author Resume:Bian Qiantao Born in 1945; graduated from the Department of Geology, South-Central University of Technology in 1970, and obtained his master's degree and doctor's degree at the Graduate School and the Institute of Geology, Chinese Academy of Sciences in 1981 and 1987, respectively. He is currently a professor of the Institute of Geology and Geophysics, Chinese Academy of Sciences, and has long been engaged in the research of tectonics, petrology, mineral deposits and

  17. Stress and strain analysis on the anastomosis site sutured with either epineurial or perineurial sutures after simulation of sciatic nerve injury☆

    Liu, Guangyao; Zhang, Qiao; Jin, Yan; Gao, Zhongli

    2012-01-01

    The magnitude of tensile stress and tensile strain at an anastomosis site under physiological stress is an important factor for the success of anastomosis following suturing in peripheral nerve injury treatment. Sciatic nerves from fresh adult cadavers were used to create models of sciatic nerve injury. The denervated specimens underwent epineurial and perineurial suturing. The elastic modulus (40.96 ± 2.59 MPa) and Poisson ratio (0.37 ± 0.02) of the normal sciatic nerve were measured by stra...

  18. Intracorporeal Suturing and Knot Tying Broadens the Clinical Applicability of Laparoscopy

    Allen, Jeff W.; Rivas, Homero; Cacchione, Robert N.; Ferzli, George S

    2003-01-01

    Objective: As surgeons become more experienced with basic laparoscopic procedures like cholecystectomy, they are able to expand this approach to less common operations. However, without laparoscopic suturing skills, like those obtained with Nissen fundoplication, many operations cannot be completed laparoscopically. We present a series of 10 patients with less common surgical illnesses who were successfully treated with minimal access techniques and intracorporeal suturing. Methods: Over a 6-...

  19. A single centre comparative study of laparoscopic mesh rectopexy versus suture rectopexy

    Manash Ranjan Sahoo

    2014-01-01

    Full Text Available Aim: The aim of our study is to compare the results of laparoscopic mesh vs. suture rectopexy. Materials and Methods: In this retrospective study, 70 patients including both male and female of age ranging between 20 years and 65 years (mean 42.5 yrs were subjected to laparoscopic rectopexy during the period between March 2007 and June 2012, of which 38 patients underwent laparoscopic mesh rectopexy and 32 patients laparoscopic suture rectopexy. These patients were followed up for a mean period of 12 months assessing first bowel movement, hospital stay, duration of surgery, faecal incontinence, constipation, recurrence and morbidity. Results: Duration of surgery was 100.8 ± 12.4 minutes in laparoscopic suture rectopexy and 120 ± 10.8 min in laparoscopic mesh rectopexy. Postoperatively, the mean time for the first bowel movement was 38 hrs and 40 hrs, respectively, for suture and mesh rectopexy. Mean hospital stay was five (range: 4-7 days. There was no significant postoperative complication except for one port site infection in mesh rectopexy group. Patients who had varying degree of incontinence preoperatively showed improvement after surgery. Eleven out of 18 (61.1% patients who underwent laparoscopic suture rectopexy as compared to nine of 19 (47.3% patients who underwent laparoscopic mesh rectopexy improved as regards constipation after surgery. Conclusion: There were no significant difference in both groups who underwent surgery except for patients undergoing suture rectopexy had better symptomatic improvement of continence and constipation. Also, cost of mesh used in laparoscopic mesh rectopexy is absent in lap suture rectopexy group. To conclude that laparoscopic suture rectopexy is a safe and feasible procedure and have comparable results as regards operative time, morbidity, bowel function, cost and recurrence or even slightly better results than mesh rectopexy.

  20. Comparison of octyl-2-cyanoacrylate and conventional sutures in facial skin closure

    Shivamurthy, D. M.; Singh, Sourav; Reddy, Sasidhar

    2010-01-01

    Introduction: Closure of wounds to achieve an esthetically pleasing result has always been a challenge. Since time immemorial, surgeons have strived to produce “invisible scars”. This, however, has always been elusive. The introduction of tissue adhesives heralded the era of suture free closures which led to better results. Aims and Objectives: The aim of this study is to compare the efficacy of octyl- 2-cyanoacrylate with that of the conventional sutures, in facial skin closure. Results and ...

  1. The outcome study of arthroscopic repair with anchor suture for anterior shoulder instabilities

    Guity MR; Sianati S

    2010-01-01

    "nBackground: Anterior glenohumeral instabilities can be corrected with open and arthroscopic surgery. The purpose of this study was to evaluate retrospectively the surgical outcomes of arthroscopic repair of anterior glenohumeral instabilities with use of suture anchors in a series of patients who were followed for twenty to fifty months."n "nMethods: The results of arthroscopic Bankart repair with use of suture anchors in 30 patients with traumatic recurrent anterior instabil...

  2. Risk/benefit evaluation of the use of triclosan in surgical suturing materials

    Lippert, Hans; Jünger, Michael; Heidecke, Claus-Dieter; Guggenbichler, Josef Peter; Assadian, Ojan; Kramer, Axel; Schauer, Frieder

    2006-01-01

    Based on the current literature, a risk/benefit analysis of the antimicrobial impregnation of surgical sutures with triclosan is performed, focussing on efficacy and indication, risk of resistance development, toxicological characteristics, and environmental tolerance. From a toxicological point of view, there are no restrictions for triclosan-impregnated suturing materials. Environmental tolerance is also acceptable for this application area, because the amounts of triclosan involved pose no...

  3. Keratometric astigmatism after ECCE in eastern Nepal. Continuous versus interrupted sutures.

    Sood Archana; Thakur Sanjay Kumar; Kumar Sandeep; Badhu Badri

    2003-01-01

    Purpose: The study aimed to compute and compare the keratometric astigmatism induced by wound closure with continuous and interrupted sutures in conventional extracapsular cataract extraction with intraocular lens implantation at a single centre in eastern Nepal. Methods: Sixty eyes of 60 patients were included in the study. All patients received conventional extracapsular cataract extraction and single piece modified C-loop posterior chamber intraocular lens. Thirty eyes were sutured with...

  4. Peripunctal "anchor" suture for securing the silicone bicanalicular stent in the repair of canalicular lacerations.

    Benger, Ross S; Nemet, Arie Y

    2008-01-01

    We used punctal absorbable suture in 8 patients (8 eyes) for silicone stent stabilization in canalicular repair surgery to prevent the postoperative complication of "cheese-wiring." Postoperatively there was 1 case of cheese-wiring of the repaired canaliculus, and no other complication related to the bicanalicular stent. The pericanalicular "anchor" suture may reduce the incidence of cheese-wiring by silicone bicanalicular stents after repair of canalicular lacerations or resections for stenosis. PMID:18209644

  5. Clinical and Radiological Evaluation after Arthroscopic Rotator Cuff Repair Using Suture Bridge Technique

    Lee, Kwang Won; Seo, Dong Wook; Bae, Kyoung Wan; Choy, Won Sik

    2013-01-01

    Background We retrospectively assessed the clinical outcomes and investigated risk factors influencing retear after arthroscopic suture bridge repair technique for rotator cuff tear through clinical assessment and magnetic resonance arthrography (MRA). Methods Between January 2008 and April 2011, sixty-two cases of full-thickness rotator cuff tear were treated with arthroscopic suture bridge repair technique and follow-up MRA were performed. The mean age was 56.1 years, and mean follow-up per...

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

    Tarabishy, Ahmad B; Thomas L Steinemann

    2010-01-01

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

  7. Studi Pengaruh Campuran 4 %, 4,5 %, Dan 5 % Polypropylene Pada Aspal Penetrasi 60/70 Terhadap Kekuatan Tekan (Compressive Strenght) Dan Uji Penyerapan Air (Water Absorption Test)

    Nasution, Arlan Budiman

    2016-01-01

    Polypropylene is used as a mixture of asphalt in this study because polypropylene has a fairly high melting point (160-166 ° C), in accordance with the processing temperature of the asphalt at a temperature of 165 ° C range. Polypropylene has a resistance to chemicals (chemical resistance) high, has a polypropylene impact strength (impact strength) high and high resistance to organic solvents such as water, polypropylene is highly resistant to water because it absorbs very little water. Addit...

  8. Iatrogenic Ulnar Nerve Injury post Laceration Suturing – An Unusual Presentation

    Murali Mothilal

    2013-07-01

    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

  9. Cranial Suture Closure in Domestic Dog Breeds and Its Relationships to Skull Morphology.

    Geiger, Madeleine; Haussman, Sinah

    2016-04-01

    Bulldog-type brachycephalic domestic dog breeds are characterized by a relatively short and broad skull with a dorsally rotated rostrum (airorhynchy). Not much is known about the association between a bulldog-type skull conformation and peculiar patterns of suture and synchondrosis closure in domestic dogs. In this study, we aim to explore breed-specific patterns of cranial suture and synchondrosis closure in relation to the prebasial angle (proxy for airorhynchy and thus bulldog-type skull conformation) in domestic dogs. For this purpose, we coded closure of 18 sutures and synchondroses in 26 wolves, that is, the wild ancestor of all domestic dogs, and 134 domestic dogs comprising 11 breeds. Comparisons of the relative amount of closing and closed sutures and synchondroses (closure scores) in adult individuals showed that bulldog-type breeds have significantly higher closure scores than non-bulldog-type breeds and that domestic dogs have significantly higher closure scores than the wolf. We further found that the prebasial angle is significantly positively correlated with the amount of closure of the basispheno-presphenoid synchondrosis and sutures of the nose (premaxillo-nasal and maxillo-nasal) and the palate (premaxillo-maxillary and interpalatine). Our results show that there is a correlation between patterns of suture and synchondrosis closure and skull shape in domestic dogs, although the causal relationships remain elusive. Anat Rec, 299:412-420, 2016. © 2016 Wiley Periodicals, Inc. PMID:26995336

  10. Keratometric astigmatism after ECCE in eastern Nepal. Continuous versus interrupted sutures.

    Sood Archana

    2003-01-01

    Full Text Available Purpose: The study aimed to compute and compare the keratometric astigmatism induced by wound closure with continuous and interrupted sutures in conventional extracapsular cataract extraction with intraocular lens implantation at a single centre in eastern Nepal. Methods: Sixty eyes of 60 patients were included in the study. All patients received conventional extracapsular cataract extraction and single piece modified C-loop posterior chamber intraocular lens. Thirty eyes were sutured with continuous (Group 1 and 30 eyes with interrupted sutures (Group 2. The results were analysed by the unpaired student′s t-test. Results: At the end of 6 weeks, Group 1 patients had significantly higher astigmatism (3.53 ± 2.19D compared to Group 2 patients (1.7 ± 1.35. A majority of patients in both groups had with-the-rule astigmatism throughout the postoperative period. Conclusion: Interrupted sutures cause less astigmatism than continuous suture. The factors responsible for high astigmatism in continuous sutures call for further analysis.

  11. Effect of Electrostatic Reduced-Gravity Environment on the Crystallographic Parameters of elt-Crystallized Polypropylene

    1999-01-01

    An electrostatic reduced-gravity device was developed and used specially for the study of the melt crystal-lization of polypropylene. The crystal structure of melt-crystallized polypropylene prepared under the reduced-gravityenvironment was investigated by using X-ray diffraction. The experiment results show that the crystal structure ofthe polypropylene is strongly dependent on the gravity applied to the sample during solidification. It is found that thecrystallographic parameters a and b increase markedly with reduced-gravity ratio, while the value of c increasesmildly.

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

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

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

    Bouza, R.; Barral, L.; Abad, M. J.; Montero, B.

    2010-06-01

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

  14. Efficacy of Single-Suture Incision Closures in Tagged Juvenile Chinook Salmon Exposed to Simulated Turbine Passage

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

    2011-09-01

    Reductions in the size of acoustic transmitters implanted in migrating juvenile salmonids have resulted in the use of a shorter incision-one that may warrant only a single suture for closure. However, it is not known whether a single suture will sufficiently hold the incision closed when fish are decompressed and when outward pressure is placed on the surgical site during turbine passage through hydroelectric dams. The objective of this study was to evaluate the effectiveness of single-suture incision closures on five response variables in juvenile Chinook salmon Oncorhynchus tshawytscha that were subjected to simulated turbine passage. An acoustic transmitter (0.43 g in air) and a passive integrated transponder tag (0.10 g in air) were implanted in each fish; the 6-mm incisions were closed with either one suture or two sutures. After exposure to simulated turbine passage, none of the fish exhibited expulsion of transmitters. In addition, the percentage of fish with suture tearing, incision tearing, or mortal injury did not differ between treatments. Expulsion of viscera through the incision was higher among fish that received one suture (12%) than among fish that received two sutures (1%). The higher incidence of visceral expulsion through single-suture incisions warrants concern. Consequently, for cases in which tagged juvenile salmonidsmay be exposed to turbine passage, we do not recommend the use of one suture to close 6-mm incisions associated with acoustic transmitter implantation.

  15. Performance Assessment of Suture Type, Water Temperature, and Surgeon Skill in Juvenile Chinook Salmon Surgically Implanted with Acoustic Transmitters

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

    2010-05-01

    This study assessed performance of seven suture types in subyearling Chinook salmon Oncorhynchus tshawytscha implanted with acoustic microtransmitters. Nonabsorbable (Ethilon) and absorbable (Monocryl) monofilament and nonabsorbable (Nurolon, silk) and absorbable (Vicryl, Vicryl Plus, Vicryl Rapide) braided sutures were used to close incisions in Chinook salmon. Monocryl exhibited greater suture retention than all other suture types 7 d after surgery. Both monofilament suture types were retained better than all braided suture types at 14 d. Incision openness and tag retention did not differ among suture types. Wound inflammation was similar for Ethilon, Monocryl, and Nurolon at 7 d. Wound ulceration was lower for Ethilon, Monocryl, and Nurolon than for all other suture types at 14 d post-surgery. Fish held in 12°C water had more desirable post-surgery healing characteristics (i.e., higher suture and tag retention and lower incision openness, wound inflammation, and ulceration) at 7 and 14 d after surgery than those held in 17°C water. The effect of surgeon was a significant predictor for all response variables at 7 d. This result emphasizes the importance of including surgeon as a variable in telemetry study analyses when multiple surgeons are used. Monocryl performed better with regard to post-surgery healing characteristics in the study fish. The overall results support the conclusion that Monocryl is the best suture material to close incisions created during surgical implantation of acoustic microtransmitters in subyearling Chinook salmon.

  16. Fusion Patterns in the Skulls of Modern Archosaurs Reveal That Sutures Are Ambiguous Maturity Indicators for the Dinosauria.

    Alida M Bailleul

    Full Text Available The sutures of the skulls of vertebrates are generally open early in life and slowly close as maturity is attained. The assumption that all vertebrates follow this pattern of progressive sutural closure has been used to assess maturity in the fossil remains of non-avian dinosaurs. Here, we test this assumption in two members of the Extant Phylogenetic Bracket of the Dinosauria, the emu, Dromaius novaehollandiae and the American alligator, Alligator mississippiensis, by investigating the sequence and timing of sutural fusion in their skulls. As expected, almost all the sutures in the emu skull progressively close (i.e., they get narrower and then obliterate during ontogeny. However, in the American alligator, only two sutures out of 36 obliterate completely and they do so during embryonic development. Surprisingly, as maturity progresses, many sutures of alligators become wider in large individuals compared to younger, smaller individuals. Histological and histomorphometric analyses on two sutures and one synchondrosis in an ontogenetic series of American alligator confirmed our morphological observations. This pattern of sutural widening might reflect feeding biomechanics and dietary changes through ontogeny. Our findings show that progressive sutural closure is not always observed in extant archosaurs, and therefore suggest that cranial sutural fusion is an ambiguous proxy for assessing maturity in non-avian dinosaurs.

  17. Fusion Patterns in the Skulls of Modern Archosaurs Reveal That Sutures Are Ambiguous Maturity Indicators for the Dinosauria.

    Bailleul, Alida M; Scannella, John B; Horner, John R; Evans, David C

    2016-01-01

    The sutures of the skulls of vertebrates are generally open early in life and slowly close as maturity is attained. The assumption that all vertebrates follow this pattern of progressive sutural closure has been used to assess maturity in the fossil remains of non-avian dinosaurs. Here, we test this assumption in two members of the Extant Phylogenetic Bracket of the Dinosauria, the emu, Dromaius novaehollandiae and the American alligator, Alligator mississippiensis, by investigating the sequence and timing of sutural fusion in their skulls. As expected, almost all the sutures in the emu skull progressively close (i.e., they get narrower) and then obliterate during ontogeny. However, in the American alligator, only two sutures out of 36 obliterate completely and they do so during embryonic development. Surprisingly, as maturity progresses, many sutures of alligators become wider in large individuals compared to younger, smaller individuals. Histological and histomorphometric analyses on two sutures and one synchondrosis in an ontogenetic series of American alligator confirmed our morphological observations. This pattern of sutural widening might reflect feeding biomechanics and dietary changes through ontogeny. Our findings show that progressive sutural closure is not always observed in extant archosaurs, and therefore suggest that cranial sutural fusion is an ambiguous proxy for assessing maturity in non-avian dinosaurs. PMID:26862766

  18. Thermal Degradation and Combustion Behavior of Polypropylene/MWCNT Composites

    Zaikov, G. E.; Rakhimkulov, A. D.; Lomakin, S. M.; Dubnikova, I. L.; Shchegolikhin, A. N.; Davidov, E. Ya.

    2010-06-01

    Studies of thermal and fire-resistant properties of the polypropylene/multi-walled carbon nanotube composites (PP/MWCNT) prepared by means of melt intercalation are discussed. The sets of the data acquired with the aid of non-isothermal TG experiments have been treated by the model kinetic analysis. The thermal-oxidative degradation behavior of PP/MWCNT and stabilizing effect caused by addition of MWCNT has been investigated by means of TGA and EPR spectroscopy. The results of cone calorimetric tests lead to the conclusion that char formation plays a key role in the mechanism of flame retardation for nanocomposites. This could be explained by the specific antioxidant properties and high thermal conductivity of MWCNT which determine high-performance carbonization during thermal degradation process. Comparative analysis of the flammability characteristics for PP-clay/MWCNT nanocomposites was provided in order to emphasize the specific behavior of the nanocomposites under high-temperature tests.

  19. Effects of the Biodegradation on Biodegradable Polymer Blends and Polypropylene

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

    2008-08-01

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

  20. Foaming Behaviour, Structure, and Properties of Polypropylene Nanocomposites Foams

    M. Antunes

    2010-01-01

    Full Text Available 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 characteristics, the nanocomposite foams were also characterized and compared with the unfilled ones regarding their dynamic-mechanical thermal behaviour. The nanocomposite foams showed higher specific storage moduli due to the reinforcement effect of the nanofillers and higher cell density isometric cellular structure. Particularly, the carbon nanofibre foams showed an increasingly higher electrical conductivity with increasing the amount of nanofibres, thus showing promising results as to produce electrically improved lightweight materials for applications such as electrostatic painting.

  1. Effect of polybutenes on mechanical and physical properties of polypropylene

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

  2. Aqueous Processes for Dyeing Generic, Unmodified Polypropylene Fiber

    Murari L. Gupta

    2010-06-01

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

  3. Preparation of polypropylene thermoplastic container via thermoforming process

    Ruqiyah Nik Hassan, Nik; Amira Mohd Ghazali, Farah; Aziz Jaafar, Abdul; Mazni Ismail, Noor

    2016-02-01

    In this study, plastic containers made of polypropylene (PP) sheets were fabricated via vacuum thermoforming. Thermoforming is a process used in fabricating plastic parts by changing flat thermoplastic sheet to three dimensional shapes. In preparing these thermoplastic containers, the design and fabrication of mould were first done by using Catia V5 software and CNC milling machine, respectively. The thermoforming process was then performed at various temperatures ranging from 160°C until 200°C on the PP sheet to form the container. From the experiment, it can be suggested that the outcomes of final thermoplastic containers are significantly depends on temperature control during thermoforming process and also the vent holes design of the mould.

  4. Reinforcing effect of nanosilica on polypropylene-nylon fibre composite

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

  5. Electrical properties of foamed polypropylene/carbon black composites

    Iliev, M.; Kotzev, G.; Vulchev, V.

    2016-02-01

    Polypropylene composites containing carbon black fillers were produced by vibration assisted extrusion process. Solid (unfoamed) composite samples were molded by conventional injection molding method, while structural foams were molded by a low pressure process. The foamed samples were evidenced to have a solid skin-foamed core structure which main parameters were found to depend on the quantity of material injected in the mold. The average bubbles' sizes and their distribution were investigated by scanning electron microscopy. It is established that the conductivity of the foamed samples gradually decreases when reducing the sample density. Nevertheless, the conductivity is found to be lower than the conductivity of the unfoamed samples both being of the same order. The flexural properties of the composites were studied and the results were discussed in the context of the structure parameters of the foamed samples.

  6. Conifer fibers as reinforcing materials for polypropylene-based composites

    Plackett, David; Chengzhi, Chuai; Almdal, Kristoffer; Poulsen, Lars

    2001-01-01

    Conifer fibers were used to reinforce polypropylene (PP). To improve the compatibility between the conifer fibers and the PP matrix, the fibers were either grafted with maleated PP (MAPP), treated by adding MAPP, or mixed with ethylene/propylene/diene terpolymer (EPDM). The treatments resulted in...... improved processing, as well as improvements in the thermal and mechanical properties of the resultant composites compared with the composites filled with untreated conifer fibers. Moreover, MAPP grafting and MAPP treating displayed more obvious benefits than EPDM treating in terms of thermal properties......, processing flowability, and tensile strength improvements. EPDM treating also produced more significant benefits than either MAPP grafting or MAPP treating in terms of impact strength and tensile elongation improvements. These improvements were attributed to surface coating of the fibers when EPDM was used...

  7. Characterization of Fibers Produced from Blends of Polybutylene and Polypropylene

    Robert L. Shambaugh, Ph.D

    2007-11-01

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

  8. Surface treated polypropylene (PP) fibres for reinforced concrete

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

    2013-12-15

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

  9. Surface treated polypropylene (PP) fibres for reinforced concrete

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

  10. Properties of lightweight cement-based composites containing waste polypropylene

    Záleská, Martina; Pavlíková, Milena; Pavlík, Zbyšek

    2016-07-01

    Improvement of buildings thermal stability represents an increasingly important trend of the construction industry. This work aims to study the possible use of two types of waste polypropylene (PP) for the development of lightweight cement-based composites with enhanced thermal insulation function. Crushed PP waste originating from the PP tubes production is used for the partial replacement of silica sand by 10, 20, 30, 40 and 50 mass%, whereas a reference mixture without plastic waste is studied as well. First, basic physical and thermal properties of granular PP random copolymer (PPR) and glass fiber reinforced PP (PPGF) aggregate are studied. For the developed composite mixtures, basic physical, mechanical, heat transport and storage properties are accessed. The obtained results show that the composites with incorporated PP aggregate exhibit an improved thermal insulation properties and acceptable mechanical resistivity. This new composite materials with enhanced thermal insulation function are found to be promising materials for buildings subsoil or floor structures.

  11. Characterization of Grafted Polypropylene-Acrylamide Films for Dye Removal

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

  12. Processing-property relationships of polypropylene/ciprofloxacin fibers

    Botta, L.; Scaffaro, R.

    2015-12-01

    In this work we prepared polypropylene (PP) fibers incorporating an antibiotic, i.e. ciprofloxacin (CFX), by melt spinning. In particular, PP has been compounded with CFX at different concentrations by using a counter-rotating twin screw compounder. The PP/CFX fibers have been spun by using a capillary rheometer operating under a constant extrusion speed. The effect of "online" hot drawing during the melt spinning or of an "offline" cold drawing on the properties of PP/CFX fibers were evaluated. In particular, the influence of the drawing conditions on the mechanical properties and the release kinetics were studied. Moreover, the rheological behavior in non-isothermal elongation flow has been assessed.

  13. Experimental study on behaviors of polypropylene fibrous concrete beams

    SUJI D.; NATESAN S.C.; MURUGESAN R.

    2007-01-01

    Synthetic fibers made from nylon or polypropylene have gained application when loose and woven into geo textile form although no information on the matrix's mechanical performance is obtained so that more understanding of their structural contribution to resist cracking can be determined. This paper presents the results of an experimental investigation to determine the performance characteristics of concrete reinforced with a polypropylene structural fiber. In this investigation "Fiber mesh" brand of fibers manufactured by SL Concrete System, Tennessee, USA and marketed by M/S Millennium Building System, Inc., Bangalore, India are used. The lengths of the fibers used were 24 mm. Fiber dosages used were 0.9, 1.8, 2.7 kg/m3. A total of three mixtures, one for each fiber dosage were made. A standard slump cone test was conducted on the fresh concrete mix with and without fibers to determine the workability of the mix. The test program included the evaluation of hardened concrete properties such as compressive, split tensile, modulus of rupture and flexural strengths. The increase in compressive strength is about 36.25%,26.20%, and 23.75% respectively that of plain concrete. This increase in strength was directly proportional to amount of fibers present in the mix. The increase in flexural strength for Mixes Ⅰ~Ⅲ is about 21%, 16.6%, and 23% respectively that of plain concrete specimens. An experimental investigation was also made to study the behaviors of reinforced fibers concrete beams (with longitudinal reinforcements) under two-point loading. The deflection and crack patterns were also studied. The improvements in strength and ductility characteristics were discussed.

  14. WESTERN EXTENSION OF THE SEVAN-AKERA SUTURE ZONE (ERZINCAN-ERZURUM REGION, TURKEY): COMPARISION OF NEW DATA CONCERNING ORIGIN, STRUCTURE AND TECTONIC EVOLUTION BETWEEN SEVAN-AKERA AND ERZINCAN SUTURE ZONES

    Hässig, Marc; Rolland, Yann; Topuz, G.; Çelik, Ö.; Sosson, Marc

    2012-01-01

    In order to better understand the tectonic evolution of the Sevan-Akera suture zone, particularly its connection westward into the Ankara-Erzincan suture, field observations and sampling were carried out on the Erzincan suture zone (near Erzincan). The goal of this study is to solve the problem of linking both odbucted ophiolitic domains. As in Armenia, the structures in Turkey are complex and have been reworked and reactivated because of post-obduction collision stages. Still, field investig...

  15. Polypropylene laminated steel sheet usable without painting; Toso kotei shoryaku kanona poripuropiren raminato gohan

    Yoshihara, R.; Wake, R.; Mizoguchi, R.; Miyoshi, K.; Nasuno, T.

    1998-05-31

    Painting with organic solves is shunned due to its environmental problems, and the lamination of steel with thermoplastic resins is being pursued in the canmaking industry. To meet this demand, Nippon Steel developed polypropylene-laminated steel sheet by the T-die lamination process that melt-extrudes polypropylene directly on steel sheet. Since the crystallization of polypropylene is controlled by optimizing the cooling conditions, a film with excellent formability and corrosion resistance is obtained. The polypropylene-laminated steel sheet is now commercially used for 18-liter cans. Their economy is expected to expand the application of T-die laminated steel sheets to include polyethylene and polyethylene terephthalate as laminating resins. (author)

  16. Effect of processing conditions on the mechanical and thermal properties of high-impact polypropylene nanocomposites

    Furlan, L.G. [Federal Institute of Rio Grande do Sul, IFRS, Campus Restinga, Estrada Joao Antonio da Silveira, 351, Porto Alegre 91790-400 (Brazil); Ferreira, C.I.; Dal Castel, C.; Santos, K.S.; Mello, A.C.E. [Chemistry Institute, Federal University of Rio Grande do Sul, UFRGS, Av. Bento Goncalves, 9500, Porto Alegre 91501-970 (Brazil); Liberman, S.A.; Oviedo, M.A.S. [Braskem S.A., III Polo Petroquimico, Via Oeste, Lote 5, Triunfo 95853-000 (Brazil); Mauler, R.S., E-mail: mauler@iq.ufrgs.br [Chemistry Institute, Federal University of Rio Grande do Sul, UFRGS, Av. Bento Goncalves, 9500, Porto Alegre 91501-970 (Brazil)

    2011-08-25

    Highlights: {yields} Polypropylene montmorillonite (PP-MMT) produced at different processing conditions. {yields} Polypropylene Nanocomposites with higher increase on impact resistance. {yields} Higher enhancement on mechanical properties. - Abstract: Polypropylene montmorillonite (PP-MMT) nanocomposites have been prepared by using a co-rotating twin screw extruder. The effects of processing conditions at fixed clay content (5 wt%) on polymer properties were investigated by means of transmission electron microscopy (TEM), flexural modulus, izod impact, dynamic mechanical analysis (DMA), and differential scanning calorimetry (DSC). It was noticed that the morphology and the mechanical properties of polypropylene nanocomposites were affected by different screw shear configuration. The results showed that the higher enhancement on mechanical properties was obtained by medium shear intensity profile instead of high configuration. An exceptional increase (maximum of 282%) on impact resistance was observed.

  17. Effect of processing conditions on the mechanical and thermal properties of high-impact polypropylene nanocomposites

    Highlights: → Polypropylene montmorillonite (PP-MMT) produced at different processing conditions. → Polypropylene Nanocomposites with higher increase on impact resistance. → Higher enhancement on mechanical properties. - Abstract: Polypropylene montmorillonite (PP-MMT) nanocomposites have been prepared by using a co-rotating twin screw extruder. The effects of processing conditions at fixed clay content (5 wt%) on polymer properties were investigated by means of transmission electron microscopy (TEM), flexural modulus, izod impact, dynamic mechanical analysis (DMA), and differential scanning calorimetry (DSC). It was noticed that the morphology and the mechanical properties of polypropylene nanocomposites were affected by different screw shear configuration. The results showed that the higher enhancement on mechanical properties was obtained by medium shear intensity profile instead of high configuration. An exceptional increase (maximum of 282%) on impact resistance was observed.

  18. Improvement of radiation resistance of polypropylene by blending with polyethylene and polystyrene

    The use of polypropylene in production of medical component and packaging materials makes it an interesting material for applied research. Since the use of ethylene oxide for sterilization of medical components will be forbidden in the next future because of its carcinogens effect. Therefore, another alternative sterilization methods are required. The use of Gamma radiation is already established for sterilization of some medical components, this technique causes change in the physical mechanical properties of polypropylene, which makes the addition of stabilizers necessary. In this work, blends of domestically used polymers, polypropylene, linear low-density polyethylene, and polystyrene/butadiene were prepared in order to improve the radiation resistance of polypropylene; naphthalene was also used as an additive

  19. Time-Dependent Response of Polypropylene/Clay Nanocomposites Under Tension and Retraction

    Drozdov, Aleksey; Christiansen, Jesper de Claville

    2013-01-01

    Observations are reported in relaxation tests under tension and retraction on polypropylene/clay nanocomposites with various contents of filler. A two-phase constitutive model is developed in cyclic viscoelasticity and viscoplasticity of nanocomposites. Adjustable parameters in the stress...

  20. Study of Mechanical Properties of Composite Material Based on Polypropylene and Vietnamese Rice Husk Filler

    Thanh Duy Tran

    2013-01-01

    Full Text Available Nowadays, the consideration of the environmental impact of polymer products has led to the development of new materials combining polymers and renewable resources. Among these materials, biocomposites have been extensively studied. In the current work, we focused on preparation of biocomposites based on polypropylene and Vietnamese rice husk flour having narrow size distribution (100–125 μm with the presence of maleic anhydride grafted polypropylene as a compatibilizer. The effect of rice husk flour and maleic anhydride grafted polypropylene content on properties of composites was investigated. The results showed that mechanical parameters as well as thermal stability were significantly improved at relatively high rice husk content by the addition of maleic anhydride grafted polypropylene.

  1. The B-Lynch uterine brace suture, and a bit of this and a bit of that...

    Karoshi, Mahantesh

    2010-03-01

    The widespread application of the B-Lynch brace suture to control postpartum hemorrhage has sparked interest in a variety of adjunctive methods, used alone or in combination, to control uterine bleeding. Although the B-Lynch brace suture has been used with good results throughout the world, failures can and do occur in rare instances, especially when the suture is incorrectly placed for use for an inappropriate indication. Four reports of additional methods to control postpartum hemorrhage are published in this issue of IJGO. Three use the B-Lynch brace suture combined with other techniques. The need for additional techniques reminds the reader of the importance of proper suture application for proper indication. Potential reasons for failure of the B-Lynch suture are provided. PMID:20070962

  2. A pilot study evaluating laparoscopic closure of the nephrosplenic space using an endoscopic suturing device in standing horses.

    Bracamonte, José L; Duke-Novakovski, Tanya

    2016-06-01

    This study evaluated the use of an articulating automated suturing device for laparoscopic closure of the nephrosplenic space in standing horses. Closure of the nephrosplenic space was performed in 4 horses using an automated suturing device. Second-look laparoscopy was performed at 5 weeks. A smooth fibrous adhesion formed between the spleen, the perirenal fascia, and the nephrosplenic ligament in 3 of the 4 horses in which the nephrosplenic space was closed using the automated suturing device. In 1 horse, closure of the nephrosplenic space was not possible due to constant breakage of the endoscopic needle. Intra-operative complications encountered with the automated suturing device were tearing of the perirenal fascia, nephrosplenic ligament, and dorsal splenic capsule along with breakage of the needle. The automated suturing device used in this study for laparoscopic closure of the nephrosplenic space resulted in longer surgery times, suffered instrument failures and delivered inadequate suture. PMID:27247467

  3. Influence of suturing material on wound healing: Experimental study in dogs

    Gazivoda Dragan

    2015-01-01

    Full Text Available Background/Aim. The most common materials implanted in the human organism are suture materials that are classified on the basis of several criteria, usually the origin, structure, and properties. The properties of suture materials are related to its absorbability and non-absorbability. When using resorbable materials it is of great importance to determine whether its absorbability and tensile strength help wound healing in function of time. Sutures themselves can become a source of inflammation, that may reduce or compromise the potential of reparation and regeneration. The aim of this experimental study on dogs was to ascertain whether the absorption rate and the degree of local tissue reactions differ from information provided by the manufacturers, whether there are differences between the applied suture materials and which of the used suture materials have better effect on wound healing. Methods. Experimental testing of the selected suture materials basic characteristics was performed on 6 German Shepherd dogs, which, after induction of general anesthesia, were made 3 identical incisions each in all 4 quadrants (left and right side of the upper and lower jaws, so that 12 horizontal incisions were formed, 10 mm long, 20-25 mm distant from one another, on each animal. Randomly, incisions were stitched up in the following order, starting from back to front: catgut, Dexon®, Vicryl-Rapid®. The experiment was terminated by histopathological examination of tissue samples, taken on postoperative day 3, 7, 14 and 21 in order to identify the effect of healing and the degree of local reaction. Results. The obtained results suggest that catgut has the highest absorption rate, while Dexon® the lowest. Vicryl-Rapid® causes the lowest level of local reactions, while Dexon® the highest. Conclusion. There is no ideal suture material because various patient factors also influence the wound healing process.

  4. The effect of polypropylene fibres within concrete with regard to fire performance in structures

    Richardson, Alan; Dave, Urmil V.

    2008-01-01

    Purpose – The purpose of this paper is to examine the effect of various polypropylene fibre additions (types and volume) to concrete with regard to explosive spalling when subject to high temperatures similar to those experienced in building or tunnel fires. Design/methodology/approach – Medium strength concrete was manufactured with varying proportions of polypropylene fibres. Plain control samples were used to determine the original concrete strength and this was used as a benchmark fo...

  5. Crosslinking Characteristics and Mechanical Properties of an Injectable Biomaterial Composed of Polypropylene fumarate and Polycaprolactone Copolymer

    Yan, Jun; Li, Jianmin; Runge, M. Brett; Dadsetan, Mahrokh; Chen, Qingshan; Lu, Lichun; Yaszemski, Michael J.

    2010-01-01

    In this work, a series of copolymers of polypropylene fumarate-co-polycaprolactone (PPF-co-PCL) were synthesized via a three-step polycondensation reaction of oligomeric polypropylene fumarate (PPF) with polycaprolactone (PCL). The effects of PPF precursor molecular weight, PCL precursor molecular weight, and PCL fraction in the copolymer (PCL feed ratio) on the maximum crosslinking temperature, gelation time, and mechanical properties of the crosslinked copolymers were investigated. The maxi...

  6. Study on Tensile Damage Constitutive Model for Multiscale Polypropylene Fiber Concrete

    Ninghui Liang; Jifei Dai; Xinrong Liu

    2016-01-01

    Polypropylene fibers perform well in roughness enhancement and corrosion resistance. They can dissipate energy when cracks occur in concrete. Furthermore, they can improve the concrete tensile properties by synergistic work with it. To study the tensile properties of the multiscale polypropylene concrete, uniaxial tensile strength of 18 fiber reinforced and 3 plain concrete specimens was experimentally tested using the paste steel method. The test results indicate that both the strength and t...

  7. Tensile strength characteristics of polypropylene composites reinforced with stone groundwood fibers from softwood

    Joan P. López,; José A. Méndez,; Francesc X. Espinach,; Fernando Julián; Pere Mutjé,; Fabiola Vilaseca

    2012-01-01

    The behavior of stone groundwood / polypropylene injection-molded composites was evaluated with and without coupling agent. Stone groundwood (SGW) is a fibrous material commonly prepared in a high yield process and mainly used for papermaking applications. In this work, the use of SGW fibers was explored as a reinforcing element of polypropylene (PP) composites. The surface charge density of the composite components was evaluated, as well as the fiber’s length and diameter inside the composit...

  8. Electrical properties of Portland cement, with the addition of polypropylene fibres - regarding durability

    Richardson, Alan

    2004-01-01

    This paper makes a comparison between the electrical properties of cement grout with and without monofilament polypropylene fibre additions. The findings show a small, but significant difference between the electrolytic transport properties of cement grout with monofilament polypropylene fibre additions when compared to grout without fibre additions. The grout with fibre additions suggests a reduced probability of water and ion transmission, due to higher measured resistivity, which will resu...

  9. LIGNIN-STIMULATED PROTECTION OF POLYPROPYLENE FILMS AND DNA IN CELLS OF MICE AGAINST OXIDATION DAMAGE

    Božena Košíková; Juraj Lábaj

    2009-01-01

    The blending of polypropylene with lignin derived from chemical wood pulp manufacture makes it possible to prepare optically transparent films (thickness 50-60μm) with acceptable mechanical properties in the absence of a commercial stabilizer. The lignin preparation in the concentration 1-2 wt% possessed the ability to act as a processing stabilizer and as an antioxidant during thermal aging of polypropylene films. A DNA-protective effect of lignin in mice testicular cells and mice peripheral...

  10. Cigarette filter material and polypropylene fibres in concrete to control drying shrinkage

    Richardson, Alan

    2012-01-01

    Due to a reduction in demand for cigarette filter material (North East UK), significant quantities have arisen that have little commercial value. The filter manufacturers have been looking for another outlet for their product and polypropylene fibre replacement in concrete was considered. The purpose of adding Type 1 polypropylene fibres (BS-EN14889) to concrete is to control plastic shrinkage and reduce bleeding. A paired comparison test was carried out to examine concrete cured under extrem...

  11. Study of Mechanical Properties of Composite Material Based on Polypropylene and Vietnamese Rice Husk Filler

    Tai Dang Tan; H. Ha Thuc; Thanh Duy Tran; C. N. Ha Thuc; Mao Dang Nguyen

    2013-01-01

    Nowadays, the consideration of the environmental impact of polymer products has led to the development of new materials combining polymers and renewable resources. Among these materials, biocomposites have been extensively studied. In the current work, we focused on preparation of biocomposites based on polypropylene and Vietnamese rice husk flour having narrow size distribution (100–125 μm) with the presence of maleic anhydride grafted polypropylene as a compatibilizer. The effect of rice hu...

  12. An interesting grafting reactivity of EB preirradiated polypropylene film[Radiation grafting; Polypropylene; Free radical; peroxide; Acrylic acid; Acrylamide

    Chen Jie E-mail: chenjjd@online.sh.cn; Yang Liming; Chen Liqin; Wu Minhong; Nho, Y.C.; Kaetsua, Isao

    2004-02-01

    An interesting grafting reactivity of electron beam preirradiated polypropylene (PP) film was found by grafting of acrylic acid (AAc) and acrylamide (AAm) repeatedly or intermittently. The preirradiated PP film could be grafted several times intermittently and the free radicals or peroxides on the samples could be determined after several times grafting reaction. The effects of storage time, reaction time and repeated reaction times on the degree of grafting were investigated. The trapped radicals, peroxy-radicals and peroxides on the preirradiated and reacted PP films were determined by using electron spin resonance (ESR) and 1,1-diphenyl-2-picryl hydrazyl (DPPH), respectively. An interpenetrating polymer networks (IPN) with both temperature and pH sensitive properties was obtained by two times grafting of AAm and AAc onto preirradiated PP film.

  13. Enhancement in Mechanical and Electrical Properties of Polypropylene Using Graphene Oxide Grafted with End-Functionalized Polypropylene

    Patchanee Chammingkwan

    2016-03-01

    Full Text Available Terminally hydroxylated polypropylene (PP synthesized by a chain transfer method was grafted to graphene oxide (GO at the chain end. Thus obtained PP-modified GO (PP-GO was melt mixed with PP without the use of a compatibilizer to prepare PP/GO nanocomposites. Mechanical and electrical properties of the resultant nanocomposites and reference samples that contained graphite nanoplatelets, partially reduced GO, or fully reduced GO were examined. The best improvement in the tensile strength was obtained using PP-GO at 1.0 wt %. The inclusion of PP-GO also led to the highest electrical conductivity, in spite of the incomplete reduction. These observations pointed out that terminally hydroxylated PP covalently grafted to GO prevented GO layers from re-stacking and agglomeration during melt mixing, affording improved dispersion as well as stronger interfacial bonding between the matrix and GO.

  14. Changes to the cell, tissue and architecture levels in cranial suture synostosis reveal a problem of timing in bone development

    J Regelsberger

    2012-11-01

    Full Text Available Premature fusion of cranial sutures is a common problem with an incidence of 3-5 per 10,000 live births. Despite progress in understanding molecular/genetic factors affecting suture function, the complex process of premature fusion is still poorly understood. In the present study, corresponding excised segments of nine patent and nine prematurely fused sagittal sutures from infants (age range 3-7 months with a special emphasis on their hierarchical structural configuration were compared. Cell, tissue and architecture characteristics were analysed by transmitted and polarised light microscopy, 2D-histomorphometry, backscattered electron microscopy and energy-dispersive-x-ray analyses. Apart from wider sutural gaps, patent sutures showed histologically increased new bone formation compared to reduced new bone formation and osseous edges with a more mature structure in the fused portions of the sutures. This pattern was accompanied by a lower osteocyte lacunar density and a higher number of evenly mineralised osteons, reflecting pronounced lamellar bone characteristics along the prematurely fused sutures. In contrast, increases in osteocyte lacunar number and size accompanied by mineralisation heterogeneity and randomly oriented collagen fibres predominantly signified woven bone characteristics in patent, still growing suture segments. The already established woven-to-lamellar bone transition provides evidence of advanced bone development in synostotic sutures. Since structural and compositional features of prematurely fused sutures did not show signs of pathological/defective ossification processes, this supports the theory of a normal ossification process in suture synostosis – just locally commencing too early. These histomorphological findings may provide the basis for a better understanding of the pathomechanism of craniosynostosis, and for future strategies to predict suture fusion and to determine surgical intervention.

  15. In Vitro Oral Biofilm Formation on Triclosan-Coated Sutures in the Absence and Presence of Additional Antiplaque Treatment

    Venema, Sebastiaan; Abbas, Frank; van de Belt-Gritter, Betsy; van der Mei, Henny C.; Busscher, Henk J.; van Hoogmoed, Chris G.

    2011-01-01

    Purpose: This study evaluated the in vitro plaque inhibitory effect of triclosan-coated polyglactin 910 sutures in the absence and presence of an additional antiplaque agent commonly used after oral surgery. Materials and Methods: Triclosan-coated sutures were incubated for 4 hours in freshly collected human saliva and, when appropriate, subsequently treated with an antiplaque rinse containing chlorhexidine-cetyl pyridinium as active components. Sutures without a triclosan-coating served as a...

  16. Photo-oxidative degradation of TiO2/polypropylene films

    Graphical abstract: - Highlights: • Photo-oxidative degradation of polypropylene is accelerated by TiO2 incorporation. • Weight loss, FTIR, SEM and GPC shown high degree of degradation of polypropylene. • A mechanism of the photo-degradation of polypropylene by TiO2 is proposed. - Abstract: Photo-oxidative degradation of polypropylene films with TiO2 nanoparticles incorporated was studied in a chamber of weathering with Xenon lamps as irradiation source. TiO2 powder with crystalline structure of anatase was synthesized by thermal treatments at 400 and 500 °C starting from a precursor material obtained by sol–gel method. Composites of TiO2/polypropylene were prepared with 0.1, 0.5 and 1.0 wt% of TiO2. The mixture of components was performed using a twin screw extruder, the resulting material was pelletized by mechanical fragmenting and then hot-pressed in order to form polypropylene films with TiO2 dispersed homogeneously. Photo-oxidative degradation process was followed by visual inspection, weight loss of films, scanning electron microscopy (SEM), infrared spectroscopy with Fourier transformed (FTIR), and gel permeation chromatography (GPC)

  17. Application to refrigerator plastics by mechanical recycling from polypropylene in waste-appliances

    Highlights: → Polypropylene is mechanically recycled from waste-appliances. → Recycled polypropylene (RPP) is impact enhanced polypropylene with ethylene-propylene rubber (EPR). → Performance evaluation shows that RPP is applicable to refrigerator plastics. -- Abstract: For the application to refrigerator plastics by mechanical recycling from polypropylene (PP) in waste-appliances, it needs to identify the degradation and heterogeneity of recycled polypropylene (RPP). It is applicable the thermal analysis such as differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA), spectroscopic analysis such as Fourier Transform Infrared (FTIR) and morphological analysis such as scanning electronic microscope (SEM). The analysis results show that RPP from waste-appliances is the polyethylene (PE) and polypropylene (PP) copolymer enhanced impact property (Impact-PP) and it is possible to apply refrigerator plastics with good impact property at low temperature. Finally, the performance evaluation of RPP is estimated by Gel Permeation Chromatography (GPC) analysis and is performed by the various mechanical and physical testing methods. It shows that RPP has relatively high molecular weight and balanced properties with strength and toughness. It is expected that RPP by the mechanical recycling from waste-appliances will have about 50% cost-merit.

  18. Effect of compatibilization and reprocessing on the isothermal crystallization kinetics of polypropylene/wood flour composites

    Arieny Rodrigues

    2013-01-01

    Full Text Available Numerous studies have focused on polymer mixtures aimed at the potential applications of these materials. This work analyzed the effect of polymer reprocessing and the type and concentration of compatibilizer on the isothermal crystallization kinetics of polypropylene/wood flour composites. The composites, which were polypropylene grafted with acrylic acid (PP-g-AA and maleic anhydride (PP-g-MA, were processed in a twin screw extruder with and without compatibilizer. Reprocessed polypropylene reached complete crystallization in less time than the composites with virgin polypropylene. The addition of wood flour to the composites did not change the kinetics significantly compared to that of the pure polymers, but the compatibilizers did, particularly PP-g-AA. The nucleation exponent (n and crystallization rate (K were calculated from Avrami plots. The values of n ranged from 2 to 3, indicating instantaneous to sporadic nucleation. The crystallization half-time of reprocessed polypropylene was shorter than that of virgin polypropylene and of the compositions containing PP-g-AA compatibilizer. The activation energy of crystallization and the equilibrium melting temperature were calculated, respectively, from Arrhenius and Hoffman-Weeks plots. Both of these parameters showed lower values in the composites, particularly in the ones containing compatibilizers.

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

    Chapala. Venkata x Venkata Ramana

    2012-12-01

    Full Text Available This analysis study is done by using different types of fibres such as steel, glass and polypropylene with aspect ratio varying from 20 to 120 for steel, 600 to 860 for glass and 30 to 100 for polypropylene fibres.The total fibre percentages of 0 to 2�0for steel, 0 to 2�0for glass and 0 to 2.5�0for polypropylene with variation of 0.25�he design mix varying from M20 to M60 with water cement ratio 0.3 to 0.55 for steel, 0.16 to 0.55 for glass and 0.46 for polypropylene.After being cured under the standard conditions for age of 28 days the specimens of each mixture were tested to determine the corresponding flexural strength. The parameters such as grade of concrete, aspect ratio, volume fraction and tensile strength of fibre for steel, glass and polypropylene fibres respectively, while the flexural strength of the concrete were chosen as output variable. The results obtained from the model and the experiments were compared by using regression analysis, and it was check in artificial neural networks. Finally form an empirical relation between flexural strength tograde of concrete, aspect ratio, volume fraction and tensile strength of fibre for steel, glass and polypropylene fibres.

  20. Radiation modification and interaction mechanism of polypropylene and polyethylene by protons and electrons

    A systematic investigation of radiation effects on isotactic polypropylene (PP) and low-density polyethylene (PE) films by protons and electrons is reported. Electrons can make polyethylene cross-linked and polypropylene crached while protons can improve the PP mechanical properties and deteriorate polyethylene with increasing the irradiation dose. The structural analysis shows that conversion between α and β phases occurs and the crystallinity remains constant in the electron-irradiated polypropylene whereas the network structure is formed by allyl-type radicals in the e--irradiated polyethylene. The infrared spectra indicate that conformational changes have taken place in the polypropylene under proton bombardment, such as the transition from an ordered to a disordered state in the crystalline region, the formation of double bonds as well as trans-conformations. This leads to the cross-linking between macromolecules of polypropylene at the proper irradiation doses, thus enhancing its mechanical properties. The cross-linking of polypropylene by proton bombardment observed and its properties may have some potential applications

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

    Omid Amanollahi

    2011-09-01

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

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

    Gabriela Silva Uchôa

    2011-12-01

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

  3. Visibility of sutures of the orbit and periorbital region using multidetector computed tomography

    Gufler, Hubert; Preis, Markus; Koesling, Sabrina [Dept. of Diagnostic Radiology, Martin-Luther-University Halle-Wittenberg, Halle (Germany)

    2014-12-15

    Knowledge of cranial suture morphology is crucial in emergency medicine, forensic medicine, and maxillofacial reconstructive surgery. This study assessed the visibility of sutures of the orbit and periorbital region on multidetector computed tomography. Multidetector computed tomography scans of 200 patients (127 males, 73 females; mean age 51.3 years; range, 6-92 years) were evaluated retrospectively. The slice thicknesses varied from 0.5 to 1 mm, and the tube current from 25 to 370 mAs, depending on the CT indication. The visibility of sutures was estimated according to a 4-point scale from 'not visible to well visible' The chi-squared test was used to test the association of the visibility of sutures with the slice thickness, tube current, and age of patients. Statistical significance was assumed at p < 0.05. Overall, best visibility was found for the sutura frontozygomatica (98%), sutura frontonasalis (88.5%), and sutura sphenozygomatica (71.5%), followed by the sutura zygomaticomaxillaris (65.8%), sutura temporozygomatica (41.8%), sutura frontomaxillaris (44.5%), and sutura sphenofrontalis (31%). Poor visibility was found for the sutura frontolacrimalis (16.8%) and sutura frontoethmoidalis (1.3%). The sutura ethmoidomaxillaris, sutura lacrimomaxillaris, and sutura ethmoidolacrimalis were not visible. Although the sutures of the superior, lateral, and inferior orbit are well visible, those of the medial orbit are poorly visible on CT scans.

  4. LED phototherapy on midpalatal suture after rapid maxilla expansion: a Raman spectroscopic study

    Rosa, Cristiane B.; Habib, Fernando Antonio L.; de Araújo, Telma M.; dos Santos, Jean N.; Cangussu, Maria Cristina T.; Barbosa, Artur Felipe S.; de Castro, Isabele Cardoso V.; Soares, Luiz Guilherme P.; Pinheiro, Antonio L. B.

    2015-03-01

    A quick bone formation after maxillary expansion would reduce treatment timeand the biomodulating effects of LED light could contribute for it. The aim of this study was to analyze the effect of LED phototherapy on the acceleration of bone formation at the midpalatal suture after maxilla expansion. Thirty rats divided into 6 groups were used on the study at 2 time points - 7 days: Control; Expansion; and Expansion + LED; and 14 days: Expansion; Expansion + LED in the first week; Expansion and LED in the first and second weeks. LED irradiation occurred at every 48 h during 2 weeks. Expansion was accomplished using a spatula and maintained with a triple helicoid of 0.020" stainless steel orthodontic wire. A LED light (λ850 ± 10nm, 150mW ± 10mW, spot of 0.5cm2, t=120 sec, SAEF of 18J/cm2) was applied in one point in the midpalatal suture immediately behind the upper incisors. Near infrared Raman spectroscopic analysis of the suture region was carried and data submitted to statistical analyzes (p≤0.05). Raman spectrum analysis demonstrated that irradiation increased hydroxyapatite in the midpalatal suture after expansion. The results of this indicate that LED irradiation; have a positive biomodulation contributing to the acceleration of bone formation in the midpalatal suture after expansion procedure.

  5. Complications and pregnancy outcome following uterine compression suture for postpartum haemorrhage: a single centre experience.

    Liu, S; Mathur, M; Tagore, S

    2014-07-01

    In the treatment of postpartum haemorrhage from uterine atony, uterine compression sutures, such as the B-Lynch suture and its modifications have a role with the advantage of preservation of the uterus for fertility. There is however, a risk that apposition of the anterior and posterior walls of the uterus will impede drainage of lochia, resulting in undesirable complications. We undertook a five-year retrospective study of all women who underwent uterine compression sutures at the KK Women's and Children's Hospital, between 2008 and 2012. In total, 23 women had uterine compression sutures during the study period, of which, nineteen women managed to conserve their uterus. Our complication rate was 25%, which included persistent vaginal discharge, pyometra and endometritis. There were three conceptions, with two successful pregnancies. Our study shows uterine compression suture to be a safe and effective alternative to avoid hysterectomy with preservation of fertility at the time of major postpartum haemorrhage. The outcome of subsequent pregnancies is reassuring. PMID:24678816

  6. Performance Assessment of Suture Type in Juvenile Chinook Salmon Surgically Implanted with Acoustic Transmitters

    Deters, Katherine A.; Brown, Richard S.; Carter, Kathleen M.; Boyd, James W.

    2009-02-27

    The objective of this study was to determine the best overall suture material to close incisions from the surgical implantation of Juvenile Salmon Acoustic Telemetry System (JSATS) acoustic microtransmitters in subyearling Chinook salmon Oncorhynchus tshawytscha. The effects of seven suture materials, four surgeons, and two water temperatures on suture retention, incision openness, tag retention, tissue inflammation, and tissue ulceration were quantified. The laboratory study, conducted by researchers at the Pacific Northwest National Laboratory, supports a larger effort under way for the U.S. Army Corps of Engineers, Portland District, aimed at determining the suitability of acoustic telemetry for estimating short- and longer-term (30-60 days) juvenile-salmonid survival at Columbia and Snake River dams and through the lower Columbia River.

  7. Allergy to Prolene Sutures in a Dural Graft for Chiari Decompression

    Iahn Cajigas

    2015-01-01

    Full Text Available Allergy to Prolene suture is exceedingly rare with only 5 cases reported in the literature. There have been no such cases associated with neurosurgical procedures. Diagnosis is nearly always delayed in spite of persistent symptomatology. A 27-year-old girl with suspected Ehlers-Danlos, connective tissue disorder, underwent posterior fossa decompression for Chiari Type 1 malformation. One year later, the patient presented with urticarial rash from the neck to chest. Cerebrospinal fluid and blood testing, magnetic resonance imaging, and intraoperative exploration did not suggest allergic reaction. Eventually skin testing proved specific Prolene allergy. After suture material was removed, the patient no longer complained of pruritus or rash. This single case highlights the important entity of allergic reaction to suture material, namely, Prolene, which can present in a delayed basis. Symptomatology can be vague but has typical allergic characteristics. Multidisciplinary approach is helpful with confirmatory skin testing as a vital part of the workup.

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

    Thorstad, Eva B.; Økland, Finn; Westerberg, Håkan;

    2013-01-01

    Effects of implanting data-storage tags in European eel, Anguilla anguilla, and the suitability of different suture materials (braided permanent silk, permanent monofilament, absorbable and absorbable antibacterial) were examined. The tags consisted of an electronic unit and three floats on a wire......, making them flexible and able to follow the swimming movements of the eel. No mortality occurred, and tagged fish did not differ from the control fish in growth. Sutures were shed or dissolved slowly. After 4 weeks, there was no difference among the groups in the proportion of sutures left. After 6....... Antibacterial treatment had no effect on inflammation or healing rates. After 6 months, the tag started to become expelled through the incision in five fish (12%). The internal reaction appeared stronger around the floats, suggesting that the coating material of the floats created a tissue reaction, which...

  9. NON ABSORBABLE INTERMITTENT MATTRESS SUTURES IN THE MANAGEMENT OF AURICULAR HAEMATOMA

    Muralidhar Reddy

    2014-12-01

    Full Text Available Auricular haematoma of pinna usually occurs secondary to trauma. If left untreated usually result in a deformity known as cauliflower ear. Various treatments are employed so as to produce the best cosmetic results. The aim of this article was to evaluate the outcome and complications of the treatment of auricular haematoma using non-absorbable 3-0 prolene intermittent sutures. This study has been performed upon eight patients presented with auricular haematoma at tertiary center, Govt. ENT Hospital, Koti, Hyderabad between August 2013 to August 2014. Follow up was continued for 6 months. The commonest cause behind auricular haematoma was personal insult. It was found that incision and drainage followed by suturing with non-absorbable intermittent mattress sutures appear to be simple, well tolerated and excellent method in treatment and preventing re-accumulation of auricular haematoma and to avoid ear deformity (Cauliflower ear.

  10. Diaphragmatic suture with tubular stomach to prevent early delayed gastric emptying after esophagectomy

    Chao Sun; Weiping Shi; Yusheng Shu; Hongcan Shi; Shichun Lu; Kang Wang

    2015-01-01

    Objective The objective of this study was to evaluate the clinical ef icacy of a diaphragmatic suture with tubular stomach to prevent delayed gastric emptying (DGE) after esophagectomy through the cervico-tho-racoabdominal approach. Methods A total of 980 patients with esophageal cancer undergoing esophagectomy through the cer-vico-thoracoabdominal approach were retrospectively included in this study and divided into two groups. Al patients underwent tubular stomach creation (group A; n = 530) or a diaphragmatic suture and tubular stomach creation (group B; n = 450). The incidence of early DGE was observed. Results The incidence of early DGE in group A was significantly higher than that in group B (P Conclusion This observation study suggests that the use of a diaphragmatic suture with tubular stomach through the cervico-thoracoabdominal approach can decrease the incidence of early DGE after esopha-gectomy.

  11. Upper lid crease approach for margin rotation in trachomatous cicatricial entropion without external sutures

    Antonio Augusto Velasco e Cruz

    2015-12-01

    Full Text Available ABSTRACT Purpose: To describe the use of a lid crease incision for upper eyelid margin rotation in cicatricial entropion combining internal traction on the anterior lamella, tarsotomy, and tarsal overlap without external sutures. Methods: Surgical description: The main steps of the procedure consisted of exposure of the entire tarsal plate up to the eyelashes followed by tarsotomy through the conjunctiva. A double-armed 6.0 polyglactin suture was then passed through the distal tarsal fragment to the marginal section of the orbicularis oculi muscle. As the sutures were tied, the distal tarsus advanced over the marginal section, and traction was exerted on the marginal strip of the orbicularis muscle. There were no bolsters or external knots. The pretarsal skin-muscle flap was closed with a 6.0 plain gut suture. Results: We used this procedure at a tertiary hospital in Saudi Arabia from 2013 to 2014. Sixty upper lids of 40 patients (23 women and 17 men were operated on, with an age range of 44-99 years [mean ± standard deviation (SD = 70.9 ± 13.01 years]. Bilateral surgery was performed on 21 patients. Follow-up ranged from 1 to 12 months (mean 3.0 ± 2.71 months. Forty percent of the patients (24 lids had more than 3 months' follow-up. The postoperative lid margin position was good in all cases. Trichiasis (two lashes was observed in only one patient with unilateral entropion on the medial aspect of the operated lid. Conclusions: The upper lid margin can be effectively rotated through a lid crease incision with internal sutures. The technique combines the main mechanisms of the Wies and Trabut approaches and avoids the use of bolsters or external sutures, which require a second consultation to be removed. Some other lid problems, such as ptosis, retraction, or dermatochalasis, can be concomitantly addressed during the procedure.

  12. Flexor tendon repair: a comparative study between a knotless barbed suture repair and a traditional four-strand monofilament suture repair.

    Joyce, C W

    2014-01-01

    We compared the tensile strength of a novel knotless barbed suture method with a traditional four-strand Adelaide technique for flexor tendon repairs. Forty fresh porcine flexor tendons were transected and randomly assigned to one of the repair groups before repair. Biomechanical testing demonstrated that the tensile strengths between both tendon groups were very similar. However, less force was required to create a 2 mm gap in the four-strand repair method compared with the knotless barbed technique. There was a significant reduction in the cross-sectional area in the barbed suture group after repair compared with the Adelaide group. This would create better gliding within the pulley system in vivo and could decrease gapping and tendon rupture.

  13. Suture Granuloma Showing False-Positive Findings on FDG-PET

    Kohei Takahara

    2013-01-01

    Full Text Available We report a case of a 33-year-old male with a mixed germ-cell testicular tumor. Postoperative follow-up FDG-PET revealed concentration of FDG in the left inguinal area which is not tumor metastasis or local recurrence but suture reactivity granuloma. In this paper, we reviewed suture granulomas associated with false-positive findings on FDG-PET after surgery. If FDG-PET will be used more frequently in the future, it will be necessary to refrain from using silk thread in order to prevent any unnecessary surgery.

  14. Radiation grafting of acrylic acid onto polypropylene films

    A study has been made for the preparation of membranes by the direct radiation grafting of acrylic acid (AAc) onto polypropylene (PP) films. The appropriate reaction conditions were selected under which the graft polymerization was carried out successfully. The effect of different solvents such as benzene, methanol/water mixture, isopropanol/water mixture, dimethyl formamide and distilled water on the swelling and grafting process of AAc onto PP films was investigated. In this grafting system ammonium ferrous sulphate (Mohr's salt) and ferric chloride were used as inhibitors to minimize the homopolymerisation of AAc and the suitable concentration of the inhibitor was found to be 1.0 and 1.5 wt% for Mohr's salt and ferric chloride, respectively. Also, the effect of monomer concentration on the rate of grafting was investigated. The dependence of the grafting rate on monomer concentration was found to be 1.1 order. This grafting system proceeded by diffusion controlled process. Some selected properties of the grafted films such as swelling behaviour, gel determination, mechanical and electrical properties were also investigated. It was found that the grafted membranes possess good hydrophilic properties which may make them promising in some practical applications. (author)

  15. Radiation-induced grafting of TMPM onto polypropylene

    The gamma radiation-induced graft copolymerization of 2,2,6,6-tetramethyl-4-piperidinyl-methacrylate (TMPM), a very effective hindered amine light stabilizer (HALS), onto polypropylene was investigated by simultaneous- irradiation technique. The various synthesis conditions on the graft content was studied. It was found that benzene, CCl4 and petroleum ether are more effective than other solvents, the percent grafting reached 7.1% for benzene. The percent grafting is higher when graft copolymerization is carried out in argon atmosphere than those in air. For all the grafting copolymerization carried out in benzene and CCl4, percent grafting increase linearly from 1 to 5 Mrad and beyond 5 Mrad, a tendency to level off appeared. At a constant dose, the percent grafting was found to be higher at high dose rate until 228 rad/s. Percent grafting also increased continuously with increasing monomer concentration up to 2.85 mol/L, but significant increase in grafting was observed only up to 1.14 mol/L

  16. Effect of Nanosilica Filled Polyurethane Composite Coating on Polypropylene Substrate

    Yern Chee Ching

    2013-01-01

    Full Text Available Acrylic based polyurethane (PU coatings with various amounts of nanosilica contents were prepared using solution casting method. The nanosilica (SiO2 particles used are around 16 nm in diameter. The friction and wear test was conducted using the reciprocating wear testing machine. The tests were performed at rotary speed of 100 rpm and 200 rpm with load of 0.1 kg to 0.4 kg under 1 N interval. The effect of the PU/nano-SiO2 composite coating on friction and wear behavior of polypropylene substrate was investigated and compared. The worn surface of coating film layer after testing was investigated by using an optical microscope. The introduction of PU/nanosilica composite coating containing 3 wt% of nano-SiO2 content gives the lowest friction coefficient and wear rate to PP substrate. Both the friction and wear rate of PP substrate coated with >3 wt% of nano-SiO2 filled PU coating would increase with the increasing of applied load and sliding time.

  17. Electret properties of biaxially stretched polypropylene films containing various additives

    Hillenbrand, J [Institute for Communications Technology, Darmstadt University of Technology, 64283 Darmstadt (Germany); Behrendt, N [Polymer Engineering, University of Bayreuth, 95447 Bayreuth (Germany); Altstaedt, V [Polymer Engineering, University of Bayreuth, 95447 Bayreuth (Germany); Schmidt, H-W [Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth (Germany); Sessler, G M [Institute for Communications Technology, Darmstadt University of Technology, 64283 Darmstadt (Germany)

    2006-02-07

    Isotactic polypropylene (i-PP) films containing additives such as the commercial {alpha} -nucleation agent NA11 and the anorganic filler particles CaCO{sub 3} and Al{sub 2}O{sub 3} were biaxially stretched. As a result, the films assume a cellular morphology with oblong cavities extending in the direction of the film elongation. In the present study, stretched films of 50 {mu}m thickness with additive concentrations of 0.05-10 mass per cent were charged with a corona method to potentials of 400 or 500 V. The stability of the charges was tested isothermally at temperatures of 90 and 120 deg. C and by means of thermally stimulated discharge (TSD) experiments. The isothermal measurements show, for the above additives with concentrations higher than about 0.3%, a reduction of the charge decay with increasing additive concentrations. Compared with reference films of pure PP, the potential decay of the films containing additive concentrations of 10% is significantly reduced. Correspondingly, the TSD measurements indicate a shift of the main discharge peak to higher temperatures up to the melting temperature. Generally, the voiding and thus the stability also increases with the stretching ratio. These improvements of the charge stability are attributed to the barrier effect of the cavities. The results are of interest with respect to the various applications of PP electrets, such as ferroelectret devices and air filters.

  18. Electret properties of biaxially stretched polypropylene films containing various additives

    Hillenbrand, J.; Behrendt, N.; Altstädt, V.; Schmidt, H.-W.; Sessler, G. M.

    2006-02-01

    Isotactic polypropylene (i-PP) films containing additives such as the commercial α -nucleation agent NA11 and the anorganic filler particles CaCO3 and Al2O3 were biaxially stretched. As a result, the films assume a cellular morphology with oblong cavities extending in the direction of the film elongation. In the present study, stretched films of 50 µm thickness with additive concentrations of 0.05-10 mass per cent were charged with a corona method to potentials of 400 or 500 V. The stability of the charges was tested isothermally at temperatures of 90 and 120 °C and by means of thermally stimulated discharge (TSD) experiments. The isothermal measurements show, for the above additives with concentrations higher than about 0.3%, a reduction of the charge decay with increasing additive concentrations. Compared with reference films of pure PP, the potential decay of the films containing additive concentrations of 10% is significantly reduced. Correspondingly, the TSD measurements indicate a shift of the main discharge peak to higher temperatures up to the melting temperature. Generally, the voiding and thus the stability also increases with the stretching ratio. These improvements of the charge stability are attributed to the barrier effect of the cavities. The results are of interest with respect to the various applications of PP electrets, such as ferroelectret devices and air filters.

  19. Mapping physicochemical surface modifications of flame-treated polypropylene

    S. Farris

    2014-04-01

    Full Text Available The aim of this work was to investigate how the surface morphology of polypropylene (PP is influenced by the surface activation mediated by a flame obtained using a mixture of air and propane under fuel-lean (equivalence ratio φ = 0.98 conditions. Morphological changes observed on flamed samples with smooth (S, medium (M, and high (H degree of surface roughness were attributed to the combined effect of a chemical mechanism (agglomeration and ordering of partially oxidized intermediate-molecular-weight material with a physical mechanism (flattening of the original roughness by the flame’s high temperature. After two treatments, the different behavior of the samples in terms of wettability was totally reset, which made an impressive surface energy of ~43 mJ•m–2 possible, which is typical of more hydrophilic polymers (e.g., polyethylene terephthalate – PET. In particular, the polar component was increased from 1.21, 0.08, and 0.32 mJ•m–2 (untreated samples to 10.95, 11.20, and 11.17 mJ•m–2 for the flamed samples S, M, and H, respectively, an increase attributed to the insertion of polar functional groups (hydroxyl and carbonyl on the C–C backbone, as demonstrated by the X-ray photoelectron spectroscopy results.

  20. Upgrading of recycled polypropylene by preparing flame retarded layered composite

    F. Ronkay

    2012-11-01

    Full Text Available 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 of mechanical properties caused by flame retardant additives. In mixed composite beside of flame retardants, the reinforcement effect of glass fibre can not be realized; therefore with modification of composite structure (but maintaining the composition a multilayer composite was developed, which contains 65.5% of recycled polymer, where the core is reinforced with glass fibre covered by flame retarded shell layers. Enhanced flame retardancy (4 min longer time to escape was achieved by using this layered composite compared to the mixed composite, thus the time to escape could be extended only with modification of composite structure.

  1. Antistatic modification of polypropylene by incorporating Tween/modified Tween

    Zheng, Anna; Xu, Xiang; Xiao, Huining; Li, Na; Guan, Yong; Li, Shuzhao

    2012-09-01

    Tween, one type of non-ionic surfactants, was used as inner antistatic agent of polypropylene (PP) and the antistatic performance of PP/Tween sheets were evaluated by surface resistivities (ρs) and water contact angles. The influence factors including hydrophile-lipophile balance (HLB) of Tween, addition amount, process conditions and atmospheric humidity were investigated in detail and the results showed Tween 40 with HLB at 15.7 provided PP an optimum antistatic effect with surface resistivity of 1010 Ω/sq, water contact angle of 57°, and surface energy of 49.5 mN/m. The ρs of PP/Tween sheets declined approximately 1 order of magnitude with 10% increasing of relative humidity. In order to improve the washing endurance of antistatic PP, a combination of T40 and cationic PP (CPP) were blended with PP and PP/CPP/T40 sheets revealed improved washing durability, with ρs below 1011 Ω/sq after ultrasound washing. In addition, T40 with double bonds was synthesized and UV crosslinking of modified T40 on PP surface also presented definite effects on water resistance.

  2. Electromagnetic interference shielding effectiveness of polypropylene/conducting fiber composites

    Lee, Pyoung-Chan; Kim, Bo-Ram; Jeoung, Sun Kyoung; Kim, Yeung Keun

    2016-03-01

    Electromagnetic released from the automotive electronic parts is harmful to human body. Electromagnetic interference (EMT) shielding refers to the reflection and/or adsorption of electromagnetic radiation by a material, which thereby acts as a shield against the penetration of the radiation through the shield. Polypropylene (PP)/conductive micro fiber composites containing various fiber contents and fiber length were injection-molded. The effect of fiber content and length on electrical properties of the composites was studied by electrical resistivity and EMT shielding measurements. The through-plane electrical conductivity and dielectric permittivity were obtained by measuring dielectric properties. The EMT shielding effectiveness (SE) was investigated by using S-parameter in the range of 100 ~ 1500 MHz. Reflection, absorption and multiple-reflection are the EMT attenuation mechanisms. From the measurement of S-Parameters, the absorption coefficient, reflection coefficient, and the shielding efficiency of the materials were calculated. The EMT SE of PP/conducing fiber composites is 40 dB over a wide frequency range up to 1.5 GHz, which is higher than that of PP/talc composite used automotive parts, viz. 0 dB.

  3. Energy harvesting from vibration with cross-linked polypropylene piezoelectrets

    Xiaoqing Zhang

    2015-07-01

    Full Text Available Piezoelectret films are prepared by modification of the microstructure of polypropylene foam sheets cross-linked by electronic irradiation (IXPP, followed by proper corona charging. Young’s modulus, relative permittivity, and electromechanical coupling coefficient of the fabricated films, determined by dielectric resonance spectra, are about 0.7 MPa, 1.6, and 0.08, respectively. Dynamic piezoelectric d33 coefficients up to 650 pC/N at 200 Hz are achieved. The figure of merit (FOM, d33 ⋅ g33 for a more typical d33 value of 400 pC/N is about 11.2 GPa−1. Vibration-based energy harvesting with one-layer and two-layer stacks of these films is investigated at various frequencies and load resistances. At an optimum load resistance of 9 MΩ and a resonance frequency of 800 Hz, a maximum output power of 120 μW, referred to the acceleration g due to gravity, is obtained for an energy harvester consisting of a one-layer IXPP film with an area of 3.14 cm2 and a seismic mass of 33.7 g. The output power can be further improved by using two-layer stacks of IXPP films in electric series. IXPP energy harvesters could be used to energize low-power electronic devices, such as wireless sensors and LED lights.

  4. Energy harvesting from vibration with cross-linked polypropylene piezoelectrets

    Zhang, Xiaoqing [Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology & School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Institute for Telecommunications Technology, Merckstrasse 25, 64283 Darmstadt (Germany); Wu, Liming [Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology & School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Sessler, Gerhard M., E-mail: g.sessler@nt.tu-darmstadt.de [Institute for Telecommunications Technology, Merckstrasse 25, 64283 Darmstadt (Germany)

    2015-07-15

    Piezoelectret films are prepared by modification of the microstructure of polypropylene foam sheets cross-linked by electronic irradiation (IXPP), followed by proper corona charging. Young’s modulus, relative permittivity, and electromechanical coupling coefficient of the fabricated films, determined by dielectric resonance spectra, are about 0.7 MPa, 1.6, and 0.08, respectively. Dynamic piezoelectric d{sub 33} coefficients up to 650 pC/N at 200 Hz are achieved. The figure of merit (FOM, d{sub 33} ⋅ g{sub 33}) for a more typical d{sub 33} value of 400 pC/N is about 11.2 GPa{sup −1}. Vibration-based energy harvesting with one-layer and two-layer stacks of these films is investigated at various frequencies and load resistances. At an optimum load resistance of 9 MΩ and a resonance frequency of 800 Hz, a maximum output power of 120 μW, referred to the acceleration g due to gravity, is obtained for an energy harvester consisting of a one-layer IXPP film with an area of 3.14 cm{sup 2} and a seismic mass of 33.7 g. The output power can be further improved by using two-layer stacks of IXPP films in electric series. IXPP energy harvesters could be used to energize low-power electronic devices, such as wireless sensors and LED lights.

  5. Improved Mechanical Properties of Compatibilized Polypropylene/Polyamide-12 Blends

    Nora Aranburu

    2015-01-01

    Full Text Available Compatibilized blends of polypropylene (PP and polyamide-12 (PA12 as a second component were obtained by direct injection molding having first added 20% maleic anhydride-modified copolymer (PP-g-MA to the PP, which produced partially grafted PP (gPP. A nucleating effect of the PA12 took place on the cooling crystallization of the gPP, and a second crystallization peak of the gPP appeared in the PA12-rich blends, indicating changes in the crystalline morphology. There was a slight drop in the PA12 crystallinity of the compatible blends, whereas the crystallinity of the gPP increased significantly in the PA12-rich blends. The overall reduction in the dispersed phase particle size together with the clear increase in ductility when gPP was used instead of PP proved that compatibilization occurred. Young’s modulus of the blends showed synergistic behavior. This is proposed to be both due to a change in the crystalline morphology of the blends on the one hand and, on the other, in the PA12-rich blends, to the clear increase in the crystallinity of the gPP phase, which may, in turn, have been responsible for the increase in its continuity and its contribution to the modulus.

  6. Radiation-induced grafting of styrene on polypropylene pellets

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

  7. Microstructure and Properties of Polypropylene/Carbon Nanotube Nanocomposites

    Dimitrios Bikiaris

    2010-04-01

    Full Text Available 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 dispersion of nanofillers and almost all the discussed properties of PP/CNTs nanocomposites are strongly related to their microstructure. PP/CNTs nanocomposites were, mainly, prepared by melt mixing and in situ polymerization. Young’s modulus, tensile strength and storage modulus of the PP/CNTs nanocomposites can be increased with increasing CNTs content due to the reinforcement effect of CNTs inside the polymer matrix. However, above a certain CNTs content the mechanical properties are reduced due to the CNTs agglomeration. The microstructure of nanocomposites has been studied mainly by SEM and TEM techniques. Furthermore, it was found that CNTs can act as nucleating agents promoting the crystallization rates of PP and the addition of CNTs enhances all other physical properties of PP. The aim of this paper is to provide a comprehensive review of the existing literature related to PP/CNTs nanocomposite preparation methods and properties studies.

  8. Benzothiazole sulfide compatibilized polypropylene/halloysite nanotubes composites

    Liu, Mingxian; Guo, Baochun; Lei, Yanda; Du, Mingliang; Jia, Demin

    2009-02-01

    Clay-philic benzothiazole sulfide, capable of donating electrons, is grafted onto polypropylene (PP) backbones when N-cyclohexyl-2-benzothiazole sulfonamide (CBS), a commonly used accelerator in the tire industry, is included in the processing of PP/halloysite nanotubes (HNTs) composites. CBS decomposes at elevated temperature and yields benzothiazole sulfide radicals, which react with the PP polymeric free radicals generated during the processing of the composites. On the other hand, the benzothiazole group of CBS is reactive to HNTs via electron transferring. The compatibilization between HNTs and PP is thus realized via interfacial grafting and electron transferring mechanism. The interfacial interactions in the compatibilized systems were fully characterized. Compared with the control sample, the dispersion of HNTs and the interfacial bonding are enhanced substantially in the compatibilized composites. The significantly improved mechanical properties and thermal properties of benzothiazole sulfide compatibilized PP/HNTs composites are correlated to the enhanced interfacial property. The present work demonstrates a novel interfacial design via interfacial grafting/electron transferring for the compatibilization of PP/clay composites.

  9. Benzothiazole sulfide compatibilized polypropylene/halloysite nanotubes composites

    Clay-philic benzothiazole sulfide, capable of donating electrons, is grafted onto polypropylene (PP) backbones when N-cyclohexyl-2-benzothiazole sulfonamide (CBS), a commonly used accelerator in the tire industry, is included in the processing of PP/halloysite nanotubes (HNTs) composites. CBS decomposes at elevated temperature and yields benzothiazole sulfide radicals, which react with the PP polymeric free radicals generated during the processing of the composites. On the other hand, the benzothiazole group of CBS is reactive to HNTs via electron transferring. The compatibilization between HNTs and PP is thus realized via interfacial grafting and electron transferring mechanism. The interfacial interactions in the compatibilized systems were fully characterized. Compared with the control sample, the dispersion of HNTs and the interfacial bonding are enhanced substantially in the compatibilized composites. The significantly improved mechanical properties and thermal properties of benzothiazole sulfide compatibilized PP/HNTs composites are correlated to the enhanced interfacial property. The present work demonstrates a novel interfacial design via interfacial grafting/electron transferring for the compatibilization of PP/clay composites.

  10. Benzothiazole sulfide compatibilized polypropylene/halloysite nanotubes composites

    Liu Mingxian [Department of Polymer Materials and Engineering, South China University of Technology, Guangzhou 510640 (China); Guo Baochun, E-mail: psbcguo@scut.edu.cn [Department of Polymer Materials and Engineering, South China University of Technology, Guangzhou 510640 (China); Lei Yanda; Du Mingliang; Jia Demin [Department of Polymer Materials and Engineering, South China University of Technology, Guangzhou 510640 (China)

    2009-02-15

    Clay-philic benzothiazole sulfide, capable of donating electrons, is grafted onto polypropylene (PP) backbones when N-cyclohexyl-2-benzothiazole sulfonamide (CBS), a commonly used accelerator in the tire industry, is included in the processing of PP/halloysite nanotubes (HNTs) composites. CBS decomposes at elevated temperature and yields benzothiazole sulfide radicals, which react with the PP polymeric free radicals generated during the processing of the composites. On the other hand, the benzothiazole group of CBS is reactive to HNTs via electron transferring. The compatibilization between HNTs and PP is thus realized via interfacial grafting and electron transferring mechanism. The interfacial interactions in the compatibilized systems were fully characterized. Compared with the control sample, the dispersion of HNTs and the interfacial bonding are enhanced substantially in the compatibilized composites. The significantly improved mechanical properties and thermal properties of benzothiazole sulfide compatibilized PP/HNTs composites are correlated to the enhanced interfacial property. The present work demonstrates a novel interfacial design via interfacial grafting/electron transferring for the compatibilization of PP/clay composites.

  11. Bacterial growth on chitosan-coated polypropylene textile.

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

    2012-01-01

    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 submerged into a growth medium inoculated with green fluorescein protein labelled Pseudomonas aeruginosa. After overnight incubation at 33°C, the textile was observed using confocal laser scanning microscopy for bacterial enumeration and biofilm structure characterisation. In the second stage, the textile was used as a filter medium for prefiltered river water, and the pressure development on the in-flow side was measured to quantify the overall level of biofouling. In both cases, nontreated textile samples were used as a control. The results indicate that the chitosan coating exhibits antibacterial properties. The developed method is applicable for the evaluation of the ability to inhibit biofilm formation. PMID:23724330

  12. Mechanical and morphological characterization of polypropylene toughened with olefinic elastomer

    Lotti Cybele

    2000-01-01

    Full Text Available The effect of incorporating (C2-C8 ethylene-octene elastomer on the mechanical properties and morphology of polypropylene copolymers has been investigated employing two types of PP copolymer, with and without nucleating agent. The results were compared to the ones presented by a commercial PP heterophase (reactor impact modified PP/EPR. The addition of the elastomer increases the toughness of the blends but reduces their stiffness. PP blends in the low elastomer content region (< 20% show low values of the Izod impact strength and both, elastomer content and impact strength, are directly proportional to the area under the beta damping peak or its maximum intensity of the elastomer. The morphology is a continuous pattern of segregate elastomeric particles with average particle size in the range of 0.27 mum to 0.39 mum. The average particle size and particle size distribution plotted in log-normal distribution curves, increases slightly with the increase in the elastomer content. The reactor modified PP heterophase has a broader particle size distribution and an average particle size of 0.56 mum, at the lower limit but inside the range for good impact performance, as observed.

  13. Effect of isotacticity on radiation stability of polypropylene

    The relationship between radiation stability and isotacticity of polypropylene(PP), such as isotactic pentad ratio, was studied in this paper. It was found that the higher isotacticity, the better radiation stability. Compared with normal PP powder which has normal isotacticity, the special PP powder with higher isotacticity, such as, isotactic pentad ratio > 98%, can keep the Melting Index change less than normal PP after UV-light-oxygen aging or γ-irradiation in air. Furthermore, the special PP powder with higher isotacticity has lower intention of crosslinking or branching after 1KGy γ-irradiation in vacuum and has lower intention of degradation after 5KGy γ-irradiation in vacuum. The special PP powder with higher isotacticity also has lower content of carbonyl after 25KGy γ-irradiation in air. These demonstrated that the special PP with higher isotacticity made from 'special catalyst' is more suitable as the material for radiation sterilization than normal PP, because there are less 'week points' in PP with higher isotacticity than that in PP with lower isotacticity. The random copolymer with 2.7% ethylene units made from the 'special catalyst' mentioned above is even more stable in irradiation sterilization than homopolypropylene with higher isotacticity; therefore, it is reasonable that a random copolypropylene with about 4%wt ethylene made from the 'special catalyst' should be the much more suitable PP material than normal PP for irradiation sterilization. (author)

  14. Flow-Induced Crystallization and Nucleation in Isotactic Polypropylenes

    Milner, Scott

    2015-03-01

    Flow-induced crystallization (FIC) occurs when a brief interval of strong flow precedes a temperature quench; many more nuclei form, resulting in a much more fine-grained solid morphology and better material properties. Common industrial polymer processing (injection molding) depends on FIC, which has been the subject of many experimental studies, most commonly on isotactic polypropylene (iPP). The prevailing hypothesis is that FIC results from flow aligning chains in the melt, increasing the melt free energy with respect to the crystal, hence acting like undercooling. Here, I combine experimental results for FIC and homogeneous nucleation with theoretical estimates for critical nuclei, to assess the prevailing hypothesis. Current best information supports the view that chain stretching (not just alignment) is necessary and sufficient to explain the observed increase in nucleation rate. Important puzzles remain: 1) shear applied at temperatures well above the equilibrium melting temperature Tm = 187 C is effective for FIC, and 2) a sheared sample may be held for hours above Tm, and still crystallize faster when quenched.

  15. Free surfaces overcome superheating in simulated melting of isotactic polypropylene

    Chen, Qin; Sirota, Eric B.; Zhang, Min; Chung, T. C. Mike; Milner, Scott T.

    The equilibrium melting point (Tm) is a challenging experimental benchmark for molecular dynamics simulation of polymer melting and crystallization. Tm obtained from melting simulation of α phase isotactic polypropylene (iPP) can exhibit superheating of over 100°C. Superheating has been attributed to the use of periodic boundary conditions and ultrafast simulated heating rates, both of which inhibit melting. We have developed a simple method to overcome superheating; we replace the periodic crystal structure with a periodic array of finite thickness slabs, separated by vacuum gaps. Thermal disorder at the slab surface promotes nucleation of the melt phase. Above Tm, we observe that the melting front advances into the crystal with a velocity proportional to T -Tm . This correspond to a quadratic rise in the system energy versus temperature, at constant heating rate. We obtain Tm as the onset of this quadratic rise in energy, which give values consistent with experimental melting points for iPP oligomers. The same simulations allow reasonable estimates of the crystal-vacuum interfacial free energy, from the energy difference between crystalline slabs and periodic crystals. The authors acknowledge support from National Science Foundation DMR-1507980.

  16. Functional behaviour of polypropylene/ZnO-soluble starch nanocomposites

    Chandramouleeswaran, Subramani [Department of Paint and Polymer Engineering and Technology, University Institute of Chemical Technology, Adenwala Road, Matunga, Mumbai-400 019 (India); Mhaske, S T [Department of Paint and Polymer Engineering and Technology, University Institute of Chemical Technology, Adenwala Road, Matunga, Mumbai-400 019 (India); Kathe, A A [Nanotechnology Research Group, Central Institute for Research on Cotton Technology, Adenwala Road, Matunga, Mumbai-400 019 (India); Varadarajan, P V [Nanotechnology Research Group, Central Institute for Research on Cotton Technology, Adenwala Road, Matunga, Mumbai-400 019 (India); Prasad, Virendra [Nanotechnology Research Group, Central Institute for Research on Cotton Technology, Adenwala Road, Matunga, Mumbai-400 019 (India); Vigneshwaran, Nadanathangam [Nanotechnology Research Group, Central Institute for Research on Cotton Technology, Adenwala Road, Matunga, Mumbai-400 019 (India)

    2007-09-26

    ZnO-polypropylene nanocomposites (nano-PP) were prepared using nanoparticles of ZnO stabilized by soluble starch (nano-ZnO) as filler in PP by the melt mixing process. X-ray diffraction (XRD) and other spectroscopic analysis-ultraviolet-visible (UV-vis), Fourier transform infrared (FTIR) and photoluminescence-revealed the presence and characteristics of nano-ZnO in the composites. The presence of ZnO imparts whiteness, while starch increased the yellowing of polymers. The nanocomposites were analyzed for changes in optical, mechanical, electrical and rheological properties, as influenced by the increasing concentration of nano-ZnO. The mechanical properties were marginally increased and the dielectric strength of the nano-PP increased to a notable level. By monitoring the evolution of the carbonyl absorption bands from FTIR analysis, the efficacy of nano-ZnO in the reduction of photo-degradation due to UV irradiation was demonstrated. The excellent antibacterial activity exhibited by nano-ZnO impregnated PP against two human pathogenic bacteria, Staphylococcus aureus and Klebsiella pneumoniae, makes it a suitable candidate for food packaging applications.

  17. The effect of nucleating agent on radiation stability of polypropylene

    The radiation stability of polypropylene (PP) with and without nucleating agent (NA) is compared in relation to radiation sterilization of medical devices. In both cases high-and-low-molecular weight PP, the addition of NA increased the transparency and peak crystallization temperature of the PP. On the other hand, in poly(propylene-co-06%ethylene) copolymer, the addition of NA did not improve the transparency but crystallization occurred at higher temperature. Thus, adding NA to PP and copolymer give the advantage of shorter moulding time in the production of medical devices. It is found that both PP and copolymer with NA are less stable during irradiation and during storage after irradiation than without NA, this being the case especially for the lower molecular weight PP. The higher transparency and peak crystallization temperature in the PP and CP with NA were found to be due to smaller spherulites. As the effect of irradiation on polymer, addition of NA induce reduction of radiation stability of polymer owing to the change in morphology. (Author)

  18. INCIDENCE OF SUTURAL BONES WITH SPECIAL REFERENCE TO SEX - A STUDY IN THE EASTERN REGION OF INDIA

    Anirban

    2013-11-01

    Full Text Available ABSTRACT: Context (Background: Many authors have studied sutural bones in various parts of the world. Examples of such work done in the Eastern Region of I ndia are not known to many in the medical community. Therefore, the authors have endeavored to give some insight into the topic and compile a baseline data of such traits by studying the incidence and distribution of various types of sutural bones in the E astern region of India. AIMS : To study the incidence and distribution of various types of sutural bones in the Eastern region of India with particular attention to sex distribution. SETTINGS AND DESIGN : A cross - sectional observational study was conducted b ased on dry adult crania in the muse um of Department of Anatomy over a period of 1 year. METHODS AND MATERIAL: 111 dry adult crania were selected as per inclusion and exclusion criteria. The number of crania with sutural bones in each sex, the total number of sutural bones in each sex and the distribution of sutural bones present bilaterally and in the midline in both males and females were studied. STATISTICAL ANALYSIS : Z - Test was performed for the distribution of sutural bones. A p - value <0.05 was consid ered significant. The results were calculated using Epi Info TM statistical software (version 3.4.1 July 3, 2007 for Windows. RESULTS : The gross incidence of sutural bones was 69.37%. The gross percentages of males and females with sutural bones were 38.74 and 30.63 respectively. Higher number of sutural bones were observed in females (188 compared to males (153. There was a statistically significant difference in the distribution of LO type of sutural bone present bilaterally between male and female cran ia. CONCLUSION: Minor variations in the ossicles of the cranium have aroused the curiosity of anatomists for many decades. Studies have shown that the presence of sutural bones is associated with other cranial and central nervous system abnormalities. The presence of sutural

  19. Characterization of calcium carbonate obtained from oyster and mussel shells and incorporation in polypropylene

    Michele Regina Rosa Hamester

    2012-04-01

    Full Text Available There is a high content of calcium carbonate in mussel and oyster shells, which can be used in the formulation of medicine, in construction or as filler in polymer materials. This work has as its main objective to obtain calcium carbonate from mussel and oyster shells and used as filler in polypropylene compared their properties with polypropylene and commercial calcium carbonate composites. The shellfish was milling and heated at 500 ºC for 2 hours. The powder obtained from shellfish were characterized by scanning electron microscopy (SEM, X-ray fluorescence, particle size distribution and abrasiveness and compared with commercial CaCO3 and mixed with polypropylene. The thermal and mechanical properties of polypropylene with CaCO3 obtained from oyster and mussel shells and with commercial CaCO3 were analysed. The results showed that CaCO3­ can be obtained from oyster and mussel shell and is technically possible to replace the commercial CaCO3 for that obtained from the shells of shellfish in polypropylene composites.

  20. Reinforcing Efficiency of Crimped Profile of Polypropylene Fibres on the Cementitious Matrix

    S. Thirumurugan

    2013-08-01

    Full Text Available Fibre reinforcement in concrete is an effective solution for improving tensile properties of concrete. Different types of fibres such as steel, polypropylene, glass and polyester were commonly used in concrete. In the present study, the effect of adding crimped polypropylene fibres on the improvement in the compressive properties of hardened concrete was studied. Crimped polypropylene fibres with different levels of reinforcements index was investigated systematically with designed concrete mixtures consisting of various fibres dosages of 0.1 to 0.5% by volume of concrete. The effect of crimped profile of polypropylene fibres on the improvement in failure properties of concrete in compression and flexural tension were evaluated. Test results showed that polypropylene fibres showed higher fracture energy absorption and exhibited a marginal improvement in strength index and sudden failure is prevented resulting in multiple splitting cracks. The ultrasonic pulse velocity test results were also found to be consistent and exhibited a good integrity for all CPFRC concrete specimens. A maximum compressive strength was noted at an optimum dosage of 3.0% of CPFRC specimens with a strength value of 24.67 and 34.92 MPa at 7 and 28 days respectively.

  1. Properties and Mechanism on Flexural Fatigue of Polypropylene Fiber Reinforced Concrete Containing Slag

    ZHANG Huili; TIAN Kanliang

    2011-01-01

    Properties and mechanism were investigated on flexural fatigue of concrete containing polypropylene fibers and ground granulated blast furnace slag(GGBFS). Four polypropylene fibers' volume fractions and five slag proportions were considered. An experiment was conducted to obtain the fatigue lives at three stress levels in 20 Hz frequency and at a constant stress level of 0.59 in four frequency respectively.Mechanism and evaluation were investigated based on the experimental data. Fatigue life span models were established. The results show that the addition of polypropylene fibers improves the flexural fatigue cumulative strength and fatigue life span. It is proposed that the slag particles and hydrated products improve Interfacial Transition Zone (ITZ) structure and benefit flexural fatigue performance. A composite reinforce effect is found with the incorporation of slag and polypropylene fibers. The optimum mixture contents 55% slag with 0.6% polypropylene fiber for the cumulative fatigue stress. Fatigue properties are decreased as the stress level increasing, the higher frequency reduces the fatigue strength more than lower frequency at a constant stress level.

  2. Resolution of 1-methylpentacyclo-[5.4.0.0sup(2,6).0sup(3,10).0sup(5,9)] undecane-8,11-dione

    Condensation of racemic 1-methylpentacyclo-[5.4.0.0sup(2,6).0sup(3,10).0sup(5,9)]undecane-8,11-dione with L-pseudo-ephedrine yielded two diastereomeric oxazolidine compounds, 7-methyl-8-oxopentacyclo[5.4.0.0sup(2,6).0sup(3,10).0sup(5,9)]undecane-(11R)-spiro-2'-threo(3',4'-dimethyl-5'-phenyl)oxazolidine and 7-methyl-8-oxopentacyclo[5.4.0.0sup(2,6).0sup(3,10).0sup(5,9)]undecane-(11S)-spiro-2'-threo(3',4'-dimethyl-5'-pheny)oxazolidine, which were separated by means of recrystallization. The chirality of the former diastereomer was demonstrated by means of X-ray crystallography. Hydrolysis of this diastereomer afforded (1R)-methylpentacyclo[5.4.0.0sup(2,6).0sup(3,10).0sup(5,9)]undecane-8,11-dione

  3. Changes in thrombocyte aggregation and in isolated thrombocyte cAMP level in rats whole-body irradiated with 5.0 and 10.0 Gy

    Rats were subjected to whole-body irradiation with doses of 5.0 Gy and 10.0 Gy. At intervals of 1.5, 3, 6, 12 and 24 hours following irradiation, the aggregation capacity was tested of thrombocytes after induction with adenosine-5-diphosphate, and the cAMP level in isolated thrombocytes was determined. Statistically significant differences between experimental and control groups were found particularly at some of the time intervals in rats irradiated with 10.0 Gy. At 3, 6 and 24 hours following irradiation with 10.0 Gy, a significant shortening was found of the time of maximal aggregation. Only at 3 hours after irradiation with 10 Gy a statistically significant reduction of the maximum aggregation occurred, compared with the control group; also the tang α value indicated a lower initial rate of aggregation. Especially after 5.0 Gy, the cAMP level in isolated thrombocytes was markedly reduced already at early intervals after irradiation. A temporary increase of the cAMP levels was recorded 3 hours after irradiation with 10.0 Gy; this might explain the reduced aggregation capacity of thrombocytes found at the same time after irradiation. The results of the two tests are not sufficient evidence of a hypercoagulation state within 24 hours after irradiation with these doses. (author). 10 figs., 15 refs

  4. A study of low temperature mechanical properties and creep behaviour of polypropylene using a new sub-ambient temperature nanoindentation test platform

    Mechanical properties and creep behaviour of an atactic-polypropylene (aPP) have been studied in the vicinity of its glass transition temperature (-18 0C) via a nanoindentation platform integrated with a sub-ambient temperature capability. All low temperature tests were validated by measurements on a fused silica reference sample from 25 to -30 0C. The fused silica results showed virtually invariant elastic modulus with temperature over this range consistent with the literature measurements by sonic resonance. Hardness and elastic modulus of aPP increased as the test temperature decreased and the amorphous regions went through the glass transition. The creep behaviour was analysed using two approaches: (i) a logarithmic method and (ii) the Boltzmann integral method. The results showed that the creep extent decreased as the temperature was reduced, and for the time constants obtained there were upper-limit values at -10 0C, about 8 0C above the quoted glass transition temperature. The strain rate sensitivity obtained by the logarithmic method also showed a maximum at -10 0C.

  5. 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

    José Guilherme Minossi

    2010-10-01

    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

  6. Comparison of surgically induced astigmatism between horizontal and X-pattern sutures in the scleral tunnel incisions for manual small incision cataract surgery

    Yadollah Eslami; Arash Mirmohammadsadeghi

    2015-01-01

    Background: Two types of popular scleral tunnel sutures in the manual small incision cataract surgery (MSICS) are horizontal and X-pattern sutures. Surgically induced corneal astigmatism (SIA) is a useful indicator of the suturing effect. Aims: To compare SIA between horizontal and X-pattern sutures in the scleral tunnel incisions for MSICS. Design: Prospective, nonrandomized comparative trial. Materials and Methods: After superior scleral tunnel incision and capsulorhexis, the nucleus was pr...

  7. B-LYNCH UTERINE COMPRESSION SUTURES IN PPH-AN EXPERIENCE AT TERTIARY CARE CENTRE

    Polumuru Usha

    2016-02-01

    Full Text Available BACKGROUND The commonest cause of postpartum hemorrhage is uterine atony. It is a serious obstetrical problem and contributes to 25-43% of all maternal deaths in the developing countries. This suture technique was described by Christopher B-Lynch in 1997 that envelope and compresses the uterus to control life-threatening postpartum hemorrhage. AIM OF THE STUDY To study the effectiveness of B-Lynch uterine compression sutures in the control of PPH. MATERIAL AND METHODS A prospective 2-year observational study, a total of 100 cases of B-Lynch was performed and results analyzed. RESULTS The study includes 100 B-Lynch applications in 12,950 deliveries. Multiparous women were at a greater risk [56%]. Obstetric complications associated with PPH were PIH [29%], APH [Placenta praevia 14% and abruption 10%], Twins [17%], anaemia [11%], polyhydramnios [4%]. Emergency LSCS was the most common procedure associated with atonic PPH [68%] followed by Elective LSCS [28%]. In this study, additional procedures required were uterine and ovarian artery ligation in 24 cases [24%] and hysterectomy in 2 cases [2%]. CONCLUSION B-Lynch suture is a valuable addition to surgical management of PPH because of its ease of application, lifesaving potential and its capacity to preserve the uterus. Hysterectomy is associated with morbidity in a young woman in addition to loss of fertility, which can be avoided by application of B-Lynch suture.

  8. Effect of the suture on the durability of bovine pericardium used in cardiac bioprostheses.

    García Paez, J M; Carrera San Martín, A; Jorge-Herrero, E; Millán, I; Navidad, R; Candela, I; García Sestafe, J V; Castillo-Olivares, J L

    1994-02-01

    Our study of the different biomaterials used in the construction of biological cardiac prostheses has shown it to be of vital importance that the physical properties of the tissue and of the suture that anchors it to the rigid polymeric support are compatible. By means of dynamic tests, we have determined the fatigue curve in sutured bovine pericardial tissue, expressed by the equation log y = 1.27 +/- 0.18 (0.26 +/- 0.05) log t, where y is the initial fatigue stress (MPa) and t is the time (min) it takes to achieve permanent deformation of the tissue. By applying this correction, we determine a set of values for stress-time which, when compared with those obtained with a non-sutured sample, reveal a significant fall in this ratio and, thus, a decrease in the durability. The use of suture threads of lesser elasticity than the pericardium may play an important role in reducing the durability of the bioprosthesis constructed with these materials. PMID:8199289

  9. Conization of the cervix uteri. Complications in connection with plain catgut or silk suturing

    Holmskov, A; Qvist, N; Møller, A

    1984-01-01

    During a retrospective study on postoperative complications in 213 patients who had undergone conization, a (non-significant) reduction in the bleeding rate from 27.9% to 18.6% was found when using silk sutures (102 patients) instead of plain catgut (111 patients) for adaption of the edges of the...

  10. Role of suture anchors in management of fractures of inferior pole of patella

    Anand Ashish

    2010-01-01

    Full Text Available Background: The traditional recommendation for displaced comminuted inferior pole fractures is excision of the comminuted pole followed by reattachment of the patellar tendon with transosseous suture. To the best of our knowledge there has been no previous published study mentioning the use of suture anchors for fracture inferior pole of patella. We present a retrospective analysis of five cases of patients doing well at final follow-up of two years. Materials and Methods: Five patients treated at our institute using suture anchors for repair of comminuted inferior pole fractures of patella between January 2007 to March 2007. (range 28 years-55 years. There were three males and two females. Results: The average follow-up was 25 months (range 24 months-26 months. The patients were evaluated for range of motion, strength, patellofemoral scores and any alteration of patellar height. The outcome of the procedure was assessed with use of the patellofemoral scoring system of Noyes et al, 5 as adapted by Saltzman et al. 6 The final patellofemoral score (maximum 100 points was 94.6 (range 93-96. Conclusion: We believe it is a novel extended indication of the use of suture anchors and should be in the armament of every trauma surgeon.

  11. Operative treatment of acromioclavicular joint dislocation: a new technique with suture anchors

    Zhang Jingwei

    2014-07-01

    Full Text Available 【Abstract】Objective: To evaluate clinical outcome of suture anchors in strengthening both acromioclavicular and coracoclavicular ligaments in the surgical treatment of acromioclavicular joint dislocation. Methods: Twenty-eight patients with acute traumatic Rockwood III, IV and V dislocations of the acromioclavicular joint surgically treated at our institute between October 2010 and January 2012 were recruited. All patients underwent open reduction combined with suture anchors. Function was evaluated using the ConstantMurley shoulder score. Clinical and radiographic shoulder ratings were evaluated using Taft criteria at 3, 6 and 12 months. Results:Two cases with fixation loosening were not included in final statistical analysis. Other patients obtained full joint reposition on immediate postoperative radiographs. Follow-up was performed with an average of 15.6 months (range, 12-19. After early range of motion exercises, 96.2% of the patients (25/26 could abduct and elevate their shoulders more than 90 degrees within postoperative 3 months. There was no infection. Average Constant-Murley score was 96.3 points (range, 94-100 and mean Taft shoulder rating was 10.7 points (range, 8-12 at 12 months. Conclusion: The suture anchor is a relatively simple technique and can avoid screw removal which is helpful in reconstructing both acromioclavicular and coracoclavicular ligaments in acute traumatic acromioclavicular joint dislocation. Key words: Acromioclavicular joint; Dislocations; Surgery; Suture anchors

  12. Interference Screw vs. Suture Anchor Fixation for Open Subpectoral Biceps Tenodesis: Does it Matter?

    Gobezie Reuben

    2008-09-01

    Full Text Available Abstract Background Bioabsorbable interference screw fixation has superior biomechanical properties compared to suture anchor fixation for biceps tenodesis. However, it is unknown whether fixation technique influences clinical results. Hypothesis We hypothesize that subpectoral interference screw fixation offers relevant clinical advantages over suture anchor fixation for biceps tenodesis. Study Design Case Series. Methods We performed a retrospective review of a consecutive series of 88 patients receiving open subpectoral biceps tenodesis with either interference screw fixation (34 patients or suture anchor fixation (54 patients. Average follow up was 13 months. Outcomes included Visual Analogue Pain Scale (0–10, ASES score, modified Constant score, pain at the tenodesis site, failure of fixation, cosmesis, deformity (popeye and complications. Results There were no failures of fixation in this study. All patients showed significant improvement between their preoperative and postoperative status with regard to pain, ASES score, and abbreviated modified Constant scores. When comparing IF screw versus anchor outcomes, there was no statistical significance difference for VAS (p = 0.4, ASES score (p = 0.2, and modified Constant score (P = 0.09. One patient (3% treated with IF screw complained of persistent bicipital groove tenderness, versus four patients (7% in the SA group (nonsignificant. Conclusion Subpectoral biceps tenodesis reliably relieves pain and improves function. There was no statistically significant difference in the outcomes studied between the two fixation techniques. Residual pain at the site of tenodesis may be an issue when suture anchors are used in the subpectoral location.

  13. The nature and location of the suture zone in the Rokelide orogen, Sierra Leone: Geochemical evidence

    Lytwyn, Jennifer; Burke, Kevin; Culver, Stephen

    2006-12-01

    The boundaries of the West African Craton mark the location of a continuous suture zone that records Neoproterozoic to Early Cambrian oceanic closure. The western part of the circum-West African suture zone extends through the line of outcrop of the Mauritanide, Bassaride and Rokelide mountain belts. Our geochemical analyses are consistent with the idea that igneous and metamorphic rocks of the Rokelide and Southern Mauritanide mountain belts of West Africa occupy a suture zone that records the closing of a Neoproterozoic to Early Cambrian ocean basin during the Pan-African orogeny and final assembly of Gondwana. The closing of that basin was marked by the collision between Archean rocks of the Leo massif of the West African Craton and reactivated Archean and Paleoproterozoic rocks that now outcrop nearer to the coast of Africa in Sierra Leone and Liberia. Within the Rokelides, the geochemistry of the Kasewe Hills volcanic rocks and Marampa amphibolite indicate that remnants of an arc system are caught up in the suture zone. The geochemistry of Guingan schists that outcrop along strike of the Rokelides is compatible with the idea that the metamorphosed equivalents of the Marampa and Kasewe Hills arc volcanic rocks extend through the Bassarides and into the Southern Mauritanides.

  14. Randomized clinical trial of self-gripping mesh versus sutured mesh for Lichtenstein hernia repair

    Jorgensen, L N; Sommer, T; Assaadzadeh, S;

    2012-01-01

    BACKGROUND: Many patients develop discomfort after open repair of a groin hernia. It was hypothesized that suture fixation of the mesh is a cause of these symptoms. METHODS: This patient- and assessor-blinded randomized multicentre clinical trial compared a self-gripping mesh (Parietene Progrip...

  15. A Wireless Sensor for Real-Time Monitoring of Tensile Force on Sutured Wound Sites.

    DeRouin, Andrew; Pacella, Nina; Zhao, Chunfeng; An, Kai-Nan; Ong, Keat Ghee

    2016-08-01

    A new wireless sensor was designed, fabricated, and applied for in situ monitoring of tensile force at a wound site. The sensor was comprised of a thin strip of magnetoelastic material with its two ends connected to suture threads for securing the sensor across a wound repair site. Since the sensor was remotely interrogated by applying an ac magnetic field and capturing the resulting magnetic field, it did not require direct wire connections to an external device or internal battery for long-term use. Due to its magnetoelastic property, the application of a tensile force changed the magnetic permeability of the sensor, altering the amplitude of the measured magnetic field. This study presents two sensor designs: one for high and one for low-force ranges. A sensor was fabricated by directly adhering the magnetoelastic strip to the suture. This sensor showed good sensitivity at low force, but its response saturated at about 1.5 N. To monitor high tensile force, the magnetoelastic strip was attached to a metal strip for load sharing. The suture thread was attached to the both ends of the metal strip so only a fraction of the applied force was directed to the sensor, allowing it to exhibit good sensitivity even at 44.5 N. The sensor was applied to two ex vivo models: a sutured section of porcine skin and a whitetail deer Achilles tendon. The results demonstrate the potential for in vivo force monitoring at a wound repair site. PMID:26340766

  16. Risk/benefit evaluation of the use of triclosan in surgical suturing materials

    Lippert, Hans

    2006-08-01

    Full Text Available Based on the current literature, a risk/benefit analysis of the antimicrobial impregnation of surgical sutures with triclosan is performed, focussing on efficacy and indication, risk of resistance development, toxicological characteristics, and environmental tolerance. From a toxicological point of view, there are no restrictions for triclosan-impregnated suturing materials. Environmental tolerance is also acceptable for this application area, because the amounts of triclosan involved pose no problems in terms of degradability. The use of surgical suturing material coated with triclosan is seen especially in contaminated wounds or where the risk of infection is high. In order to meet this requirement, the antimicrobial properties of triclosan are particularly emphasized.Both in vitro and in vivo, triclosan is highly effective against Staphylococcus spp., including MRSA, the pathogens most frequently involved in postoperative wound infections. Triclosan is not effective against Pseudomonas aeruginosa, Serratia marcescens and Alcaligenes spp., due to their intrinsic resistance against this agent.As long as the inducible resistance in vitro against triclosan is not clinically relevant, it does not speak against triclosan use in suturing material, especially because pure triclosan is applied only to a specific, limited area for a short time. However, because triclosan can induce in vitro the development of cross-resistances to antibiotics, the implementation of this agent must be exclusively limited to medically founded indications.

  17. Adjustment of gamma radiation doses for sterilization of Egyptian surgical sutures

    The adjustment of gamma radiation doses for sterilization of catguts under local manufacturing conditions has been performed. Average total initial counts for aerobic and anaerobic bacteria per item were relatively low, in the range of 1000 counts for aerobic and 10 counts for anaerobic bacteria. The microfiora (aerobic bacteria) of the studied sutures were isolated and identified to be: Bacillus sp.; Micrococcus varians, Micrococcus roseus, and Staphylococcus. Each purified and identified isolate was exposed to gamma radiation both in liquid media (broth) and in the preservative in which the sutures were supplied by the company. The LD values of the most resistant microorganisms in both case of liquid media and preservative, were obtained to be around 5 KGy. Deliberately contaminated sterile sutures with each isolate and with mixture of isolates were studied. The sterilizing dose was obtained to be 20KGy for most heavily contaminated items (1010 counts) irradiated both in saline and in preservative. This sterilizing dose was found to be dependent of the initial viable counts. This value was considered to be a safe value for radiosterilization of the studied sutures preserved in isopropyl alcohol, glycerin, and water (90:3.5:16)

  18. Randomized comparison of polyglycolic acid and polyglyconate sutures for abdominal fascial closure after laparotomy in patients with suspected impaired wound healing

    Osther, P J; Gjøde, P; Mortensen, Sophie Berit Bondegaard; Mortensen, P B; Bruhn, Jesper Bartholin; Gottrup, F

    1995-01-01

    to the development of fascial disruption and incisional hernia. Wound infection demanding surgical intervention was found in 7 per cent of patients with polyglyconate sutures and in 16 per cent of those with polyglycolic acid sutures (P = 0.04). Monofilament polyglyconate suture does not reduce the...

  19. Morphological, viscoelastic and mechanical characterization of polypropylene/exfoliated graphite nanocomposites

    Creusa Iara Ferreira

    2013-01-01

    Full Text Available The viscoelastic, mechanical and morphological properties of polypropylene/exfoliated graphite nanocomposites with different contents of nanofiller were investigated. According to transmission electron microscopy results, the nanofiller particles were homogeneously dispersed in the matrix. The rheological properties indicated that incorporation of graphite improved the matrix stiffness and had a reinforcing effect. Exfoliated graphite had a weak interaction with the polypropylene. The behavior of the nanocomposites was similar to that of polypropylene in terms of the interfacial detachment inferred from the transmission electron microscopy images and of their G' (storage and G'' (loss moduli, and viscosity. The mechanical properties of the nanocomposites compared to the matrix improved significantly for the flexural and storage moduli with little loss of impact strength.

  20. CO-PYROLYSIS OF POLYPROPYLENE WITH PETROLEUM OF BACIA DE CAMPOS

    DE ASSUMPÇÃO, Luiz Carlos Fonte Nova; MARQUES, Mônica Regina da Costa; CARBONELL, Montserrat Motas

    2009-01-01

    Full Text Available In this study, the process of co-pyrolysis of polypropylene (PP residues with gas-oil was evaluated, varying thetemperature and the amount of polypropylene fed to the reactor. The polypropylene samples and gas-oil weresubmitted to the thermal co-pyrolysis in an inert atmosphere, varying the temperature and the amount of PP.The influence of the gas-oil was evaluated carrying the co-pyrolysis in the absence of PP. The pyrolysed liquidsproduced by this thermal treatment were characterized by modified gaseous chromatography in order toevaluate the yield in the range of distillation of diesel. As a result, the increase of PP amount lead to a reductionin the yield of the pyrolytic liquid and to an increase of the amount of solid generated. The effect of temperatureincrease showed an inverse result. The results show that plastic residue co-pyrolysys is a potential method forchemical recycling of plastic products.

  1. Essential work of fracture analysis for starch filled poly(propylene carbonate) composites

    Starch filled poly(propylene carbonate) composites are environmental friendly materials. In this study, the fracture toughness of composites under mode I loading was determined by the essential work of fracture concept. The specific essential fracture work of the poly(propylene carbonate)/starch composites decreases with increasing the starch content, while the non-essential work term, βw p increases with increasing the starch content. In addition, the morphologies, thermal properties, thermo-mechanical properties were studied by scanning electron microscope, thermogravimetric analysis, dynamic mechanical analysis, and differential scanning calorimetry, respectively. The thermal and thermo-mechanical measurements revealed that increasing starch content led to an increase in glass transition temperature and thermal stability. Morphology observation indicates that poly(propylene carbonate) and starch have weak interfacial adhesion

  2. Estimation of radiation dose rate in new polypropylene strainer in primary heat transport system

    Heavy water is used in Primary Heat Transport system at Dhruva research reactor. It contains suspended and ionic impurities, therefore it is required to purify heavy water for removal of impurities and to maintain grade of heavy water. For enhancing performance of purification system testing of new polypropylene filters is planned for removal of suspended impurities at flow rate of 400 lit/min. Physical properties of polypropylene changes after exposure to radiation after radiation dose of 1.0E+05 Gy it becomes brittle. Calculations of beta and gamma radiation dose rate are based on the activity of radionuclides present in heavy water used as main coolant system. Assessment of service life of new filters is carried out by calculating the radiation dose rate to polypropylene filters during in service and radiation dose rate of existing removed stainless steel strainer. (author)

  3. Surface modification of polypropylene using argon plasma: Statistical optimization of the process variables

    Low pressure plasma treatment using radiofrequency (rf) discharge of argon gas was employed to improve the hydrophilicity of polypropylene. The effects of argon plasma on the wettability, surface chemistry and surface morphology of polypropylene were studied using static contact angle measurements, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Increase in surface energy of polypropylene was observed as a result of argon plasma treatment. SEM and AFM images revealed the increased surface roughness. A set of identified process variables (rf power, pressure, argon flow rate and time) were used in this study and were optimized using central composite design (CCD) of response surface methodology (RSM). A statistical model was developed to represent the surface energy in terms of the process variables mentioned above. Accuracy of the model was verified and found to be high.

  4. Study of microcellular injection-molded polypropylene/waste ground rubber tire powder blend

    Microcellular polypropylene/waste ground rubber tire powder blend processing was performed on an injection-molding machine with a chemical foaming agent. The molded samples produced based on the design of experiments (DOE) matrices were subjected to tensile testing and scanning electron microscope (SEM) analyses. Molding conditions and waste ground rubber tire (WGRT) powder have been found to have profound effects on the cell structures and mechanical properties of polypropylene (PP) and waste ground rubber tire powder composite samples. The result shows that microcellular PP/WGRT blend samples exhibit smaller cell size and higher cell density compare with polypropylene resin. Among the molding parameters studied, chemical foaming agent weight percentage has the most significant effect on cell size, cell density, and tensile strength. The results also suggest that tensile strength of microcellular PP/WGRT composites is sensitive to weight reduction, and skin thickness.

  5. Morphological, viscoelastic and mechanical characterization of polypropylene/exfoliated graphite nanocomposites

    Ferreira, Creusa Iara; Oliveira, Ricardo Vinicius Bof de; Mauler, Raquel Santos, E-mail: raquel.mauler@ufrgs.br [Universidade Federal do Rio Grande do Sul (PGCIMAT/IQ/UFRGS), Porto Alegre, RS (Brazil); Bianchi, Otavio [Universidade de Caxias do Sul (PGMAT/CCET/UCS), RS (Brazil); Oviedo, Mauro Alfredo Soto [Braskem S/A, Rio de Janeiro, RJ (Brazil)

    2013-07-01

    The viscoelastic, mechanical and morphological properties of polypropylene/exfoliated graphite nanocomposites with different contents of nanofiller were investigated. According to transmission electron microscopy results, the nanofiller particles were homogeneously dispersed in the matrix. The rheological properties indicated that incorporation of graphite improved the matrix stiffness and had a reinforcing effect. Exfoliated graphite had a weak interaction with the polypropylene. The behavior of the nanocomposites was similar to that of polypropylene in terms of the interfacial detachment inferred from the transmission electron microscopy images and of their G' (storage) and G' (loss) moduli, and viscosity. The mechanical properties of the nanocomposites compared to the matrix improved significantly for the flexural and storage moduli with little loss of impact strength. (author)

  6. Interfacial enhancement of polypropylene composites modified with sorbitol derivatives and siloxane-silsesquioxane resin

    Dobrzyńska-Mizera, Monika, E-mail: monika.dobrzynska-mizera@doctorate.put.poznan.pl; Sterzyński, Tomasz [Poznan University of Technology, Institute of Materials Technology, Polymer Division, Piotrowo, 3, 61-138 Poznan (Poland); Dutkiewicz, Michał [Centre for Advanced Technologies, Adam Mickiewicz University, Umultowska 89 C, 61-614 Poznan (Poland); Di Lorenzo, Maria Laura [Consiglio Nazionale delle Ricerche, Istituto per i Polimeri, Compositi e Biomateriali, c/o Comprensorio Olivetti, Via Campi Flegrei, 34, 80078 Pozzuoli (Italy)

    2015-12-17

    Composites based on polypropylene (iPP) modified with a sorbitol derivative (NX8000) and siloxane-silsesquioxane resin (SiOPh) containing maleated polypropylene (MAPP) as compatibilizer were prepared by melt extrusion. Calorimetric investigations were carried out using differential scanning calorimetry (DSC), whereas the morphological and mechanical properties were investigated by scanning electron microscopy (SEM) and static tensile tests. DSC measurements revealed no influence of SiOPh and a slight effect of MAPP addition on the crystallization kinetics of polypropylene. Additionally, the introduction of MAPP into the iPP+NX8000+SiOPh composites increased plastic properties of the samples. All the above was attributed to the compatibilizing effect of MAPP which improved interfacial adhesion between iPP, NX8000 and SiOPh. This phenomenon was also confirmed by the SEM images illustrating more homogenous distribution of the filler in the compatibilized samples.

  7. Gamma irradiation assisted fungal degradation of the polypropylene/biomass composites

    Butnaru, Elena; Darie-Niţă, Raluca Nicoleta; Zaharescu, Traian; Balaeş, Tiberius; Tănase, Cătălin; Hitruc, Gabriela; Doroftei, Florica; Vasile, Cornelia

    2016-08-01

    White-rot fungus Bjerkandera adusta has been tested for its ability to degrade some biocomposites materials based on polypropylene and biomass (Eucalyptus globulus, pine cones, and Brassica rapa). γ-irradiation was applied to initiate the degradation of relatively inert polypropylene matrix. The degradation process has been studied by scanning electron microscopy, atomic force microscopy, infrared spectroscopy, contact angle measurements, rheological and chemiluminescence tests. These analyses showed that the polypropylene/biomass composites properties are worsen under the action of the selected microorganism. The formation of cracks and scrap particles over the entire matrix surface and the decrease of the complex viscosity values, as well as the dynamic moduli of gamma irradiated PP/biomass composite and exposed to Bjerkandera adusta fungus, indicate fungal efficiency in composite degradation.

  8. Microcrystalline-cellulose and polypropylene based composite: A simple, selective and effective material for microwavable packaging.

    Ummartyotin, S; Pechyen, C

    2016-05-20

    Cellulose based composite was successfully designed as active packaging with additional feature of microwavable properties. Small amount of cellulose with 10 μm in diameter was integrated into polypropylene matrix. The use of maleic anhydride was employed as coupling agent. Thermal and mechanical properties of cellulose based composite were superior depending on polypropylene matrix. Crystallization temperature and compressive strength were estimated to be 130 °C and 5.5 MPa. The crystal formation and its percentage were therefore estimated to be 50% and it can be predicted on the feasibility of microwavable packaging. Morphological properties of cellulose based composite presented the good distribution and excellent uniformity. It was remarkable to note that cellulose derived from cotton can be prepared as composite with polypropylene matrix. It can be used as packaging for microwave application. PMID:26917383

  9. Flammability of polypropylene/organoclay nanocomposites; Inflamabilidade de nanocompositos de polipropileno/argila organofilica

    Alves, Tatianny Soares; Barbosa, Renata, E-mail: tsaeng3@yahoo.com.br [Universidade Federal do Piaui (UFPI), Teresina (Brazil); Carvalho, Laura Hecker de [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Canedo, Eduardo Luis [Instituto de Tecnologia de Pernambuco, Recife (Brazil)

    2014-11-01

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

  10. Laser-induced selective copper plating of polypropylene surface

    Ratautas, K.; Gedvilas, M.; Stankevičiene, I.; JagminienÄ--, A.; Norkus, E.; Li Pira, N.; Sinopoli, S.; Emanuele, U.; Račiukaitis, G.

    2016-03-01

    Laser writing for selective plating of electro-conductive lines for electronics has several significant advantages, compared to conventional printed circuit board technology. Firstly, this method is faster and cheaper at the prototyping stage. Secondly, material consumption is reduced, because it works selectively. However, the biggest merit of this method is potentiality to produce moulded interconnect device, enabling to create electronics on complex 3D surfaces, thus saving space, materials and cost of production. There are two basic techniques of laser writing for selective plating on plastics: the laser-induced selective activation (LISA) and laser direct structuring (LDS). In the LISA method, pure plastics without any dopant (filler) can be used. In the LDS method, special fillers are mixed in the polymer matrix. These fillers are activated during laser writing process, and, in the next processing step, the laser modified area can be selectively plated with metals. In this work, both methods of the laser writing for the selective plating of polymers were investigated and compared. For LDS approach, new material: polypropylene with carbon-based additives was tested using picosecond and nanosecond laser pulses. Different laser processing parameters (laser pulse energy, scanning speed, the number of scans, pulse durations, wavelength and overlapping of scanned lines) were applied in order to find out the optimal regime of activation. Areal selectivity tests showed a high plating resolution. The narrowest width of a copper-plated line was less than 23 μm. Finally, our material was applied to the prototype of the electronic circuit board on a 2D surface.

  11. Uterine compression suture technique in the management of severe postpartum haemorrhage as an alternative to hysterectomy

    Stanojević Dušan

    2009-01-01

    Full Text Available Introduction. One of the most dramatic conditions in obstetrics is definitely bleeding from the uterus which fails to compress. This condition is known as postpartum atony. When such a condition is diagnosed, the obstetrician has a choice of several conservative methods to stimulate the uterus to contract and several surgical methods to stop the bleeding. The most extreme measure used to save the patient's life and stop the bleeding is hysterectomy. This surgery is characterized by high morbidity, primarily by the loss of woman's fertility. In order to avoid hysterectomy, several authors have introduced the compressive uterine suture technique into gynaecological practice. Objective. The aim of the paper is to demonstrate the technique of applying compressive uterine suture after delivery to stop excessive bleeding, and to present results obtained by this technique. Methods. The paper explains the technique of applying compressive suture to the atonic uterus in cases when all other procedures to stop excessive bleeding after delivery fail. Since uterine atony is the main reason for excessive and uncontrollable bleeding after childbirth, the need to perform such surgery is rather common. Authors demonstrate the technique of applying four compressive sutures which prevent uterus dilation and thus stop the bleeding. Results. Compressive suture technique was used by the authors eight times, seven of which during caesarean section and one after spontaneous delivery. All patients had normal postpartum period and normal involution of the uterus. Conclusion. Although this surgery requires a skilful and experienced obstetrician, the authors find it rather easy to perform and it is suggested to be applied in all cases of uterine atony when excessive bleeding cannot be stopped by other any other method except hysterectomy. This surgical procedure saves the uterus and facilitates quick and easy patient's recovery.

  12. Fracture Properties of Polypropylene Fiber Reinforced Concrete Containing Fly Ash and Silica Fume

    Qingfu Li; Peng Zhang

    2013-01-01

    A parametric experimental study has been conducted to investigate the effect of polypropylene fiber on the fracture properties of concrete containing fly ash and silica fume, with five fiber volume fraction (0.04, 0.06, 0.08, 0.1 and 0.12%) used. The results indicate that the addition of polypropylene fiber has greatly improved the fracture parameters of concrete composite containing 15% fly ash and 6% silica fume, such as fracture toughness, fracture energy, effective crack length, maximum m...

  13. Strength and porosity of concrete incorporating polypropylene and steel fibres subjected to high temperature

    The aim of this study is to investigate the effect of polypropylene and steel fibres on the behaviour of concrete subjected to high temperature. Test were carried out on concrete elements subjected to four target temperatures: 150, 300, 450 and 600 deg C. Three groups of concrete were studied: one group of concrete mixes without fibre, one group of concrete mixes with polypropylene fibres and one group of concrete with steel fibres. The specimens were subjected to heating - cooling cycles from the ambient temperature to 150 deg C, 300 deg C, 450 deg C and 600 deg C

  14. CHARACTERISTICS OF STRUCTURE OF IMPACT COPOLYMERS OF POLYPROPYLENE WITH LOW ETHYLENE CONTENTS

    MA Dezhu; LI Xiqiang; ZHANG Ruiyun; HONG Kunlun; LUO Xiaolie

    1994-01-01

    In the present work, the structure and impact properties of copolymers of polypropylene with low ethylene contents have been investigated. Based on the results of 13C-NMR, FTIR,WAXD, DSC, PLM and SEM, the relationship between impact properties and morphology of the copolymers has been discussed. The high impact properties of copolymer ICP2 may attribute to the relatively higher ethylene content and homogeneous ethylene unit distribution. The size and its distribution of spherulite in the copolymers and cycloid cavities dispersed in polypropylene continue phase may also be two important factors which affect the impact properties of these materials.

  15. Enhancing the Dyeability of Polypropylene Fibers by Melt Blending with Polyethylene Terephthalate

    Fereshteh Mirjalili

    2013-01-01

    Full Text Available Attempts were made to modify polypropylene fibers by melt blending with polyethylene terephthalate in order to enhance the dyeability of the resultant fiber. Five blends of polypropylene/polyethylene terephthalate/compatibilizer were prepared and subsequently spun into fibers. Three disperse dyes were used to dye such modified fibers at boiling and 130°C. The dyeing performance of the blend fibers, as well as the morphological, chemical, thermal, and mechanical properties, of the corresponding blends was characterized by means of spectrophotometry, polarized optical microscopy, scanning electron microscopy (SEM, FT-IR spectroscopy, differential scanning calorimetry (DSC, and tensile testing.

  16. Thermal analysis of polypropylene modified by gamma irradiation composites under outdoor conditions

    Komatsu, Luiz G.H.; Oliani, Washington L.; Lugao, Ademar B.; Parra, Duclerc F., E-mail: dfparra@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    This work reports the influence of the clay in the degradation process of the HMSPP.The polypropylene (PP) was irradiated under acetylene atmosphere in gamma irradiation source ({sup 60}Co) to obtain the HMSPP (high melt strength polypropylene). Composites of HMSPP were processed in twin-screw extruder with clay Cloisite 20A and Maleic Anhydride (PP-g-MA) as coupling agent. The obtained composites were exposed under outdoor conditions for 6 months. The ageing effects were characterized by Differential Scanning Calorimetry (DSC), Thermogravimetry Analysis (TGA). Chemical oxidation was evaluated by Carbonyl Index (IC) through infrared Spectroscopy (FT-IR). The results showed correlation between carbonyl index and ageing time. (author)

  17. Static and fatigue behaviour of glass-fibre-reinforced polypropylene composites

    Ferreira, J. A. M.; Costa, J. D. M.; Reis, P. N. B.

    1999-01-01

    This paper is concerned with fatigue of polypropylene/glass-fibre thermoplastic composites produced from a bi-directional woven cloth mixture of E glass fibres and polypropylene fibres. The latter becomes the matrix after the application of heat and pressure. This composite was manufactured with a fibre volume fraction Vf of 0.338. The effect of layer design on the static and fatigue performance was investigated. The S-N curves, the rise in the temperature of the specimens during the tests an...

  18. Free radicals in irradiated unstabilized polypropylene, as seen by diffuse reflection absorption-spectrophotometry

    The introduction of UV-Vis absorption spectrophotometry to the study of radiation chemistry of polymers has opened the possibility to investigate even very opaque samples. The virgin powder polypropylene, as obtained from the industrial production line, shows after irradiation unstable products of radiolysis. Until now they were investigated mainly by EPR method. Optical absorption spectra (by diffuse reflection spectrophotometry) contribute to better identification and study of changes in time, temperature and diffusion of reactive gases. Studying the formation of stable compounds, which do not produce EPR signal, we are able to examine these species on the basis of their electronic spectra. The most important results concern the peroxides in irradiated polypropylene

  19. Development of a Halogen Free Flame Retardant Masterbatch for Polypropylene Fibers

    François Rault

    2015-02-01

    Full Text Available The efficiency of new phosphinates, in combination with melamine cyanurate, was studied using different polypropylene textile structures. The influence of different ratios up to a total amount of 6 wt% in the polypropylene fiber was investigated using the limiting oxygen index (LOI and cone calorimeter method for research purposes, while the performances were correlated to the standards FMVSS 302 (Federal Motor Vehicle Safety Standards and DIN 4102-l (Deutsches Institut für Normung used more specifically for automotive and building sector.

  20. Polypropylene/graphite nanocomposites by in situ polymerization; Nanocompositos polipropileno/grafite via polimerizacao in situ

    Milani, Marceo A.; Galland, Giselda B., E-mail: griselda@iq.ufrgs.br [Instituto de Quimica, UFRGS, Porto Alegre, RS (Brazil); Quijada, Raul [Universidade de Chile, Santiago (Chile). Centro de Ciencias de los Materiales; Basso, Nara R.S. [Fac. de Quimica, PUCRS, Porto Alegre, RS (Brazil)

    2011-07-01

    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){sub 2}ZrCl{sub 2} or rac-Me{sub 2}Si(Ind){sub 2}ZrCl{sub 2} 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)

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

    Lucilene B. de Paiva

    2006-06-01

    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.

  2. Radiological assessment of skull base changes in children with syndromic craniosynostosis: role of ''minor'' sutures

    Calandrelli, Rosalinda; D' Apolito, Gabriella; Gaudino, Simona; Stefanetti, Mariangela; Colosimo, Cesare [Universita Cattolica Sacro Cuore, Institute of Radiology, Rome (Italy); Massimi, Luca; Di Rocco, Concezio [Universita Cattolica Sacro Cuore, Institute of Neurosurgery, Rome (Italy)

    2014-10-15

    This study aims to identify the premature synostosis of ''major'' and ''minor'' sutures of the four ''sutural arches'' of the skull and to perform a morphometric analysis in children with syndromic craniosynostosis in order to evaluate changes in the skull base linked with premature suture synostosis. We reviewed multiplanar high-resolution CT images, implemented with 3D reconstructions, from 18 patients with complex syndromic craniosynostosis and compared them with 18 age-matched healthy subjects. We assessed the calvarial sutures and their extension to the skull base, and then we correlated specific types of synostosis with the size, shape and symmetry of the cranial fossae. We found a marked asymmetry of the skull base growth in all patients. The synostotic involvement around the coronal ring caused a reduction in the growth of the anterior and middle fossae. The size of the posterior cranial fossa was related not only to ''major'' but also to ''minor'' suture synostosis of the lambdoid and parieto-squamosal arches. Changes in the skull base and craniofacial axis symmetry are due to structural and functional relationships between ''major'' and ''minor'' skull sutures, suggesting a structural and functional relationship between the neurocranium and basicranium. The early recognition of prematurely closed skull base sutures may help clinicians and neurosurgeons to establish correct therapeutic approaches. (orig.)

  3. The red-eared slider turtle carapace under fatigue loading: The effect of rib-suture arrangement.

    Achrai, Ben; Daniel Wagner, H

    2015-08-01

    Biological structures consisting of strong boney elements interconnected by compliant but tough collagenous sutures are abundantly found in skulls and shells of, among others, armadillos, alligators, turtles and more. In the turtle shell, a unique arrangement of alternating rigid (rib) and flexible (suture) elements gives rise to superior mechanical performance when subjected to low and high strain-rate loadings. However, the resistance to repeated load cycling - fatigue - of the turtle shell has yet to be examined. Such repeated loading could approximately simulate the consecutive high-stress bending loads exerted during (a predator) biting or clawing. In the present study flexural high-stress cyclic loads were applied to rib and suture specimens, taken from the top dorsal part of the red-eared slider turtle shell, termed carapace. Subsequently, to obtain a more complete and integrated fatigue behavior of the carapace, specimens containing a complex alternating rib-suture-rib-suture-rib configuration were tested as well. Although the sutures were found to be the least resistant to repeated loads, a synergistic effect was observed for the complex specimens, displaying improved fatigue durability compared to the individual (suture or even rib) constituents. This study may assist in the design of future high-stress fatigue-resistant materials incorporating complex assemblies of rigid and flexible elements. PMID:26042699

  4. LigLAP: Encirclement and Ligation of Vessels in Laparoscopic Surgery: A Double-Layer Suture Sealing Approach.

    Yousefian, Reza; Jones, Paul; Kia, Michael A; Zadeh, Mehrdad Hosseini

    2015-12-01

    This article proposes a potential automatic ligation (LigLAP) method to occlude vessels and ducts in several laparoscopic surgical procedures. Currently, stapling devices are widely used for this purpose. However, there are some complications associated with stapling devices, including biliary leak and tissue damage. In this article, we examine the feasibility of an alternative method that uses a double-layer suture to encircle and occlude a vessel. A heating element melts the outer layer of the suture at the cross-point of the suture to create a seal. Several electromechanical mechanisms have been proposed to carry out this ligation process. In addition, some parts have been prototyped for experimental verification and visualization. Several double-layered sutures have been created, and their tensile strength and sealing capabilities have been measured. Moreover, a simple leakage experiment has been performed to verify experimentally the idea of using the double-layer suture. The results show that the new suture and the thermal sealing method provide the required strength to occlude balloons filled with water. Although the results suggest that the proposed method and the double-layer suture may be used in surgical ligation processes, much more rigorous testing of leakage is required. PMID:25918125

  5. Assessment of mechanical properties and dimensions of suture threads utilized in orthopedic surgeries

    Sardenberg Trajano

    2003-01-01

    Full Text Available Surgical materials of monofilament nylon (0, 3-0 and 4-0, braided polyester (0, 3-0 and 4-0 and monofilament polypropylene (0, 3-0 and 4-0 of 7 trademarks commercialized in Brazil, was submitted to analysis of diameter, length, enchasement resistance, tensile strength of surgery materials knotted and unknotted, according to ABNT. The results show that most of surgical materials was inside of preconizing patterns of ABNT.

  6. Properties of Reactive Compatibilized Dika Nutshell Powder filled Recycled Polypropylene (PP/Polyethylene Terephthalate (PET Biocomposites using Maleated Polypropylene and Epoxy Resin Dual Compatibilizers

    G. N. Onyeagoro

    2013-01-01

    Full Text Available Dika nutshell powder (DNS filled – recycled polypropylene (PP/polyethylene terephthalate (PET biocomposite was prepared by reactive compatibilization using maleic anhydride-grafted-polypropylene (MAPP and epoxy resin (EPR as dual compatibilizers. The mechanical and rheological properties, as well as sorption behavior of the compatibilized biocomposites were studied at filler loadings of 0, 2, 4, 6, 8, and 10 phr (parts per hundred parts of resin. PP/PET composition was fixed at 30/70 wt. %. The results show that when MAPP alone was used as compatibilizer, property improvements were not substantial due to the low reactivity between MAPP and PET, which produces insignificant amount of copolymers as coupling agent at the interfaces. Effective compatibilization was achieved by adding epoxy resin (EPR as suggested by impressive improvement in the properties investigated. Outstanding property improvements, especially oil resistance, tensile and impact strengths (higher values, and elongation at break (lower value were obtained with increases in EPR and filler loadings.

  7. Impingement syndrome of the shoulder following double row suture anchor technique for arthroscopic rotator cuff repair: a case report

    Rambani Rohit

    2009-06-01

    Full Text Available Abstract Introduction Arthroscopic repair of the rotator cuff is a demanding surgery. Accurate placement of anchors is key to success. Case presentation A 38-year-old woman received arthroscopic repair of her rotator cuff using a double row suture anchor technique. Postoperatively, she developed impingement syndrome which resulted from vertical displacement of a suture anchor once the shoulder was mobilised. The anchor was removed eight weeks following initial surgery and the patient had an uneventful recovery. Conclusion Impingement syndrome following arthroscopic repair of the rotator cuffs using double row suture anchor has not been widely reported. This is the first such case where anchoring has resulted in impingement syndrome.

  8. Fatores de risco no tratamento de lesões do ceco com sutura primária em ratos Risk factors on the treatment of cecum injuries with primary suture in rats

    Gustavo Pereira Fraga

    2004-12-01

    ência de deiscência também foi maior nos ratos que apresentavam contaminação fecal mais intensa da cavidade peritoneal. A intensidade da peritonite no momento da sutura observada no exame histológico não teve associação com a ocorrência de complicações da sutura primária. Conclusão: A sutura primária é um procedimento de risco para tratar ratos, transcorrido intervalo superior a seis horas após o trauma, ou na vigência de contaminação intensa da cavidade por fezes.Purpose: Analyze the results of primary suture in the treatment of cecum traumatic injuries in rats, after the exposure to increasing time intervals between the trauma and the surgery and with different peritonitis degrees. Methods: In a randomized double-blinded study, 96 Wistar male rats, weight ranging between 200 and 250 grams, underwent laparotomy, in which a 5-milimiter-diameter-injury in the contramesenteric edge of the cecum was performed. In 12 animals of the control-group a prompt primary suture was executed, with total and separated stitches, with 7.0 polypropylene thread. In the other groups, with 12 animals each, a laparotomy for repair of the injury was executed after intervals of 30 minutes, 1, 2, 4, 6, 9 and 12 hours. At the time of injury repair, one of its edges was ressected and sent for anatomopathological examination. A daily control after the surgery was done, observing the presence of complications, specially dehiscence of the suture, and the euthanasia of the animals were done in the 1st, 4th, 7th and 14th day after the surgery. Necropsy was executed in all animals, observing the macroscopic and microscopic findings in the area of suture. Results: There was no association between the delay for surgical treatment of the injury and peritonitis degrees. The mortality in the 14 animals with diffuse peritonitis was 100%. Global mortality was 25% (24 animals, and 6 animals (25% died before treatment. None of the animals treated that evolved to death had complications related

  9. Chondrocyte behavior on nanostructured micropillar polypropylene and polystyrene surfaces

    This study was aimed to investigate whether patterned polypropylene (PP) or polystyrene (PS) could enhance the chondrocytes' extracellular matrix (ECM) production and phenotype maintenance. Bovine primary chondrocytes were cultured on smooth PP and PS, as well as on nanostructured micropillar PP (patterned PP) and PS (patterned PS) for 2 weeks. Subsequently, the samples were collected for fluorescein diacetate-based cell viability tests, for immunocytochemical assays of types I and II collagen, actin and vinculin, for scanning electronic microscopic analysis of cell morphology and distribution, and for gene expression assays of Sox9, aggrecan, procollagen α1(II), procollagen α1(X), and procollagen α2(I) using quantitative RT-PCR assays. After two weeks of culture, the bovine primary chondrocytes had attached on both patterned PP and PS, while practically no adhesion was observed on smooth PP. However, the best adhesion of the cells was on smooth PS. The cells, which attached on patterned PP and PS surfaces synthesized types I and II collagen. The chondrocytes' morphology was extended, and an abundant ECM network formed around the attached chondrocytes on both patterned PP and PS. Upon passaging, no significant differences on the chondrocyte-specific gene expression were observed, although the highest expression level of aggrecan was observed on the patterned PS in passage 1 chondrocytes, and the expression level of procollagen α1(II) appeared to decrease in passaged chondrocytes. However, the expressions of procollagen α2(I) were increased in all passaged cell cultures. In conclusion, the bovine primary chondrocytes could be grown on patterned PS and PP surfaces, and they produced extracellular matrix network around the adhered cells. However, neither the patterned PS nor PP could prevent the dedifferentiation of chondrocytes. - Highlights: • Methods to avoid chondrocyte dedifferentiation would be useful for cartilage repair. • Cell culture

  10. The role of the sutures in biomechanical dynamic simulation of a macaque cranial finite element model: implications for the evolution of craniofacial form.

    Wang, Qian; Wood, Sarah A; Grosse, Ian R; Ross, Callum F; Zapata, Uriel; Byron, Craig D; Wright, Barth W; Strait, David S

    2012-02-01

    The global biomechanical impact of cranial sutures on the face and cranium during dynamic conditions is not well understood. It is hypothesized that sutures act as energy absorbers protecting skulls subjected to dynamic loads. This hypothesis predicts that sutures have a significant impact on global patterns of strain and cranial structural stiffness when analyzed using dynamic simulations; and that this global impact is influenced by suture material properties. In a finite element model developed from a juvenile Rhesus macaque cranium, five different sets of suture material properties for the zygomaticotemporal sutures were tested. The static and dynamic analyses produced similar results in terms of strain patterns and reaction forces, indicating that the zygomaticotemporal sutures have limited impact on global skull mechanics regardless of loading design. Contrary to the functional hypothesis tested in this study, the zygomaticotemporal sutures did not absorb significant amounts of energy during dynamic simulations regardless of loading speed. It is alternatively hypothesized that sutures are mechanically significant only insofar as they are weak points on the cranium that must be shielded from unduly high stresses so as not to disrupt vitally important growth processes. Thus, sutural and overall cranial form in some vertebrates may be optimized to minimize or otherwise modulate sutural stress and strain. PMID:22190334

  11. Study on Welding Mechanism Based on Modification of Polypropylene for Improving the Laser Transmission Weldability to PA66

    Huixia Liu

    2015-08-01

    Full Text Available Polypropylene and PA66 are widely used in our daily life, but they cannot be welded by laser transmission welding (LTW because of polar differences and poor compatibility. In this paper, grafting modification technology is used to improve the welding performance between polypropylene and PA66. Firstly, the strong reactive and polar maleic-anhydride (MAH is grafted to polypropylene and infrared spectrometer is used to prove that MAH has been grafted to polypropylene. At the same time, the mechanical and thermal properties of the graft modified polypropylene (TGMPP are tested. The results prove that the grafting modification has little influence on them. Also, the optical properties of TGMPP are measured. Then, the high welding strength between TGMPP and PA66 is found and the mechanism of the weldability is researched, which shows that there are two reasons for the high welding strength. By observing the micro morphology of the welding zone, one reason found is that the modification of polypropylene can improve the compatibility between polypropylene and PA66 and make them easy to diffuse mutually, which causes many locking structures formed in the welding region. The other reason is that there are chemical reactions between TGMPP and PA66 proved by the X-ray photoelectron spectrometer.

  12. Polypropylene /Aspen/ liquid polybutadienes composites: maximization of impact strength, tensile and modulus by statistical experimental design

    Kokta, B. V.; Fortelný, Ivan; Kruliš, Zdeněk; Horák, Zdeněk; Michálková, Danuše

    2005-01-01

    Roč. 99, - (2005), s. 10-11. ISSN 0009-2770. [International Conference on Polymeric Materials in Automotive , Slovak Rubber Conference /17./. 10.5.2005-12.5.2005, Bratislava] Institutional research plan: CEZ:AV0Z40500505 Keywords : polypropylene * Aspen-PP composite Subject RIV: CD - Macromolecular Chemistry

  13. Radiation degradation of polypropylene - immediate and long term effects on average molecular weights

    Three types of polypropylenes commercially available for production of single use syringes were studied. All are intended (and used) for products sterilized by radiation. Average molecular weights were determined immediately after and at different times up to more than 2.5 years, after irradiation. (author)

  14. Protein repellent hydrophilic grafts prepared by surface-initiated atom transfer radical polymerization from polypropylene

    Fristrup, Charlotte Juel; Jankova Atanasova, Katja; Eskimergen, Rüya;

    2012-01-01

    Grafting of poly(ethylene glycol)methacrylate (PEGMA) and N,N-dimethylacrylamide (DMAAm) from UV-initiator modified polypropylene (PP) was performed by Surface-Initiated Atom Transfer Radical Polymerization (SI-ATRP). The modification and hydrophilization of the PP substrates were confirmed with ...

  15. Tensile behaviour of isotactic polypropylene modified by specific nucleation and active fillers

    Kotek, Jiří; Kelnar, Ivan; Baldrian, Josef; Raab, Miroslav

    2004-01-01

    Roč. 40, č. 4 (2004), s. 679-684. ISSN 0014-3057 R&D Projects: GA ČR GP106/02/P027 Keywords : polypropylene * .beta.--phase * CaCO3 filler Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.419, year: 2004

  16. Morphological factor in the melting point depression of polypropylene by alkanes

    Šimek, L.; Dostál, J.; Bohdanecký, Miloslav

    2001-01-01

    Roč. 42, č. 21 (2001), s. 8897-8900. ISSN 0032-3861 R&D Projects: GA AV ČR KSK4050111 Institutional research plan: CEZ:AV0Z4050913 Keywords : isotactic polypropylene * n- alkanes * melting point depression Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.681, year: 2001

  17. Spinning, drawing and physical properties of polypropylene nanocomposite fibers with fumed nanosilica

    Dabrowska, I.; Fambri, L.; Pegoretti, A.; Šlouf, Miroslav; Vacková, Taťana; Kolarik, J.

    2015-01-01

    Roč. 9, č. 3 (2015), s. 277-290. ISSN 1788-618X R&D Projects: GA ČR(CZ) GA14-17921S Institutional support: RVO:61389013 Keywords : polypropylene * fibers * nanocomposites Subject RIV: JI - Composite Materials Impact factor: 2.761, year: 2014

  18. Anti static agent characterization in polypropylene by using combined instrumental techniques

    Antistatic agents are substances with are added to plastics molding formulations or to the surface of molded articles to minimize the accumulation of static electricity. The analysis and characterization of an antistatic agent in polypropylene using combined techniques provides very specific and detailed information. (author)

  19. Radiation compatibilization of polyamide-6/polypropylene blends, enhanced by the presence of compatibilizing agent

    Radiation compatibilization of polyamide-6 (PA6)/polypropylene (PP) blends was obtained by pre-irradiation of PP by gamma or electron beam irradiation, and enhanced in blends with PP-g-MA (maleic anhydride). Thermal behavior and morphological development were determined by DSC, X-ray and SEM. Compatibilization was confirmed by xylene extraction and Molau test

  20. On explicit modeling of polypropylene fiber effects on hydro-thermal behavior of heated concrete

    Tran V.H.

    2013-09-01

    Full Text Available This work focuses on the evaluation of the probability of percolation of polypropylene fibers (PPF in creating a permeable network within heated concreted due to temperature induced degradation of fibers. Therefore, the intrinsic permeability supply of heated concrete containing PPF is accordingly estimated by a homogenization technique applied to the 3D heterogeneous microstructure.

  1. Evaluation of polypropylene mesh coated with biological hydrogels for temporary closure of open abdomen.

    Deng, Youming; Ren, Jianan; Chen, Guopu; Li, Guanwei; Guo, Kun; Hu, Qiongyuan; Wu, Xiuwen; Wang, Gefei; Gu, Guosheng; Li, Jieshou

    2016-08-01

    Polypropylene mesh, as a temporary abdominal closure device, may cause mechanical intestine injury and inflammatory response. Chitosan/gelatin hydrogel has excellent biocompatibility, soft and elastic properties. This work is to assess the effects of the chitosan/gelatin hydrogel coated polypropylene mesh on open abdomen wounds. Histological analysis and detection of healing-related factors were conducted to evaluate the inflammation and wound healing process. After 1-day implantation in a murine model of open abdomen, the coated polypropylene mesh, compared with simple polypropylene mesh, demonstrated well protection of the intestine serosa. After 14-day implantation, it reduced the inflammation response by down-regulating the cytokines interleukin-6 and tumor necrosis factor-α, and up-regulating the anti-inflammatory factor interleukin-10. Meanwhile, the composite stimulated granulation tissue growth, and promoted matrix deposition and angiogenesis after 7 and 14 days. In conclusion, the modified temporary abdominal closure composite could significantly protect the intestines from mechanical damage and accelerate wound healing. PMID:27114442

  2. A novel approach in organic waste utilization through biochar addition in wood/polypropylene composites

    Das, Oisik [Department of Civil and Environmental Engineering, University of Auckland, Auckland 1142 (New Zealand); Sarmah, Ajit K., E-mail: a.sarmah@auckland.ac.nz [Department of Civil and Environmental Engineering, University of Auckland, Auckland 1142 (New Zealand); Bhattacharyya, Debes [Department of Mechanical Engineering, Center for Advanced Composite Materials, University of Auckland, Auckland 1142 (New Zealand)

    2015-04-15

    Highlights: • Biochar made from waste wood was added with wood polypropylene composites. • 24% biochar gave the best mechanical properties. • 6% biochar had no effect on physico-mechanical properties of composites. • Coupling agent remained unreacted in composites having higher amount of biochar. - Abstract: In an attempt to concurrently address the issues related to landfill gas emission and utilization of organic wastes, a relatively novel idea is introduced to develop biocomposites where biochar made from pyrolysis of waste wood (Pinus radiata) is added with the same wood, plastic/polymer (polypropylene) and maleated anhydride polypropylene (MAPP). Experiments were conducted by manufacturing wood and polypropylene composites (WPCs) mixed with 6 wt%, 12 wt%, 18 wt%, 24 wt%, and 30 wt% biochar. Though 6 wt% addition had similar properties to that of the control (composite without biochar), increasing biochar content to 24 wt% improved the composite’s tensile/flexural strengths and moduli. The biochar, having high surface area due to fine particles and being highly carbonised, acted as reinforcing filler in the biocomposite. Composites having 12 wt% and 18 wt% of biochar were found to be the most ductile and thermally stable, respectively. This study demonstrates that, WPCs added with biochar has good potential to mitigate wastes while simultaneously producing biocomposites having properties that might be suited for various end applications.

  3. Preparation and thermal behaviour of a series of liquid wood-polypropylene composites

    Blanco, Ignazio; Cicala, Gianluca; Latteri, Alberta; Saccullo, Giuseppe

    2016-05-01

    Liquid Wood (a mixture of cellulose, hemp, fax and lignin) was used to prepare, by mechanical mixing followed by thermal extrusion, blends of various Polypropylene (PP)/Liquid Wood ratios. To verify if and how much the composition of the obtained composites affects their thermal properties Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) experiments were carried out.

  4. Nanocomposites of polypropylene/titanate nanotubes: morphology, nucleation effects of nanoparticles and properties

    Mikešová, Jana; Šlouf, Miroslav; Gohs, U.; Popelková, Daniela; Vacková, Taťana; Vu, Ngoc Húng; Kratochvíl, Jaroslav; Zhigunov, Alexander

    2014-01-01

    Roč. 71, č. 4 (2014), s. 795-818. ISSN 0170-0839 R&D Projects: GA ČR GAP205/10/0348 Institutional support: RVO:61389013 Keywords : titanate nanotubes * polypropylene nanocomposites * nucleation effect Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.438, year: 2014

  5. The stopping power and energy straggling of heavy ions in silicon nitride and polypropylene

    Mikšová, Romana; Hnatowicz, Vladimír; Macková, Anna; Malinský, Petr; Slepička, P.

    2015-01-01

    Roč. 354, JUL (2015), s. 205-209. ISSN 0168-583X R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk LM2011019 Institutional support: RVO:61389005 Keywords : stopping power * heavy ions * polypropylene * silicon nitride Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.124, year: 2014

  6. Using Raman spectroscopic imaging for non-destructive analysis of filler distribution in chalk filled polypropylene

    Boros, Evelin; Porse, Peter Bak; Nielsen, Inga;

    2016-01-01

    A feasibility study on using Raman spectral imaging for visualization and analysis of filler distribution in chalk filled poly-propylene samples has been carried out. The spectral images were acquired using a Raman spectrometer with 785 nm light source.Eight injection-molded samples with...

  7. Jute fiber reinforced polypropylene produced by continuous extrusion compounding. Part 1. Processing and ageing properties

    Oever, van den M.J.A.; Snijder, M.H.B.

    2008-01-01

    This article addresses the processing and ageing properties of jute fiber reinforced polypropylene (PP) composites. The composite has been manufactured by a continuous extrusion process and results in free flowing composite granules, comprising up to 50 weight percent (wt %) jute fiber in PP. These

  8. Properties and Semicrystalline Structure Evolution of Polypropylene/Montmorillonite Nanocomposites under Mechanical Load

    Stribeck, Norbert; Zeinolebadi, Ahmad; Ganjaee Sari, Morteza;

    2012-01-01

    Small-angle X-ray scattering (SAXS) monitors tensile and load-cycling tests of metallocene isotactic polypropylene (PP), a blend of PP and montmorillonite (MMT), and two block copolymer compatibilized PP/MMT nanocomposites. Mechanical properties of the materials are similar, but the semicrystalline...

  9. Electrochemical preparation of ether ketones from (poly)propylene glycol monoethers

    This invention is a method for preparing an ether ketone comprising electrolyzing a solution containing a (poly)propylene glycol monoether, hydroxyl ions and optionally water in an electrolytic cell having an anode at least partially coated with nickel peroxide, silver peroxide, cobalt peroxide or copper peroxide

  10. A novel approach in organic waste utilization through biochar addition in wood/polypropylene composites

    Highlights: • Biochar made from waste wood was added with wood polypropylene composites. • 24% biochar gave the best mechanical properties. • 6% biochar had no effect on physico-mechanical properties of composites. • Coupling agent remained unreacted in composites having higher amount of biochar. - Abstract: In an attempt to concurrently address the issues related to landfill gas emission and utilization of organic wastes, a relatively novel idea is introduced to develop biocomposites where biochar made from pyrolysis of waste wood (Pinus radiata) is added with the same wood, plastic/polymer (polypropylene) and maleated anhydride polypropylene (MAPP). Experiments were conducted by manufacturing wood and polypropylene composites (WPCs) mixed with 6 wt%, 12 wt%, 18 wt%, 24 wt%, and 30 wt% biochar. Though 6 wt% addition had similar properties to that of the control (composite without biochar), increasing biochar content to 24 wt% improved the composite’s tensile/flexural strengths and moduli. The biochar, having high surface area due to fine particles and being highly carbonised, acted as reinforcing filler in the biocomposite. Composites having 12 wt% and 18 wt% of biochar were found to be the most ductile and thermally stable, respectively. This study demonstrates that, WPCs added with biochar has good potential to mitigate wastes while simultaneously producing biocomposites having properties that might be suited for various end applications

  11. Origin of toughness in .beta.-polypropylene: the effect of molecular mobility in the amorphous phase

    Policianová, Olivia; Hodan, Jiří; Brus, Jiří; Kotek, Jiří

    2015-01-01

    Roč. 60, 9 March (2015), s. 107-114. ISSN 0032-3861 R&D Projects: GA ČR(CZ) GA13-29009S Institutional support: RVO:61389013 Keywords : isotactic polypropylene * β-modification * toughness Subject RIV: JI - Composite Materials Impact factor: 3.562, year: 2014

  12. Effect of tetraethoxysilane coating on the improvement of plasma treated polypropylene adhesion

    Polypropylene is one of the most used polymers due to its lightweight and recyclability properties, among others. However, its poor characteristics regarding surface energy and lack of polar functional groups have to be overcome to perform adhesion processes. The main objective of this work is to improve the adhesion behavior of polypropylene by combining atmospheric pressure plasma surface activation and silane adhesion promoter. Tetraethoxysilane hydrolysis and condensation are followed through infrared spectroscopy by attenuated total reflectance in order to set the coating conditions. Contact angle measurements and surface energy calculations as well as infrared and X-ray photoelectron spectroscopy are used to evaluate polymer chemical modifications. Morphological changes are studied through scanning electron and atomic force microscopy. Results show the ability of plasma treatment to create active oxydised functional groups on the polypropylene surface. These groups lead to a proper wetting of the polymer by the silane. Shear strength of single-lap bonding of polypropylene with a polyurethane adhesive suffers a significant improvement when the silane coating is applied on previously plasma activated samples. It has been also demonstrated that the silane curing conditions play a decisive role on the adhesion response. Finally, the stability of the silane solution is tested up to 30 days, yielding diminished but still acceptable adhesion strength values.

  13. Effect of tetraethoxysilane coating on the improvement of plasma treated polypropylene adhesion

    Pantoja, M.; Encinas, N.; Abenojar, J.; Martínez, M. A.

    2013-09-01

    Polypropylene is one of the most used polymers due to its lightweight and recyclability properties, among others. However, its poor characteristics regarding surface energy and lack of polar functional groups have to be overcome to perform adhesion processes. The main objective of this work is to improve the adhesion behavior of polypropylene by combining atmospheric pressure plasma surface activation and silane adhesion promoter. Tetraethoxysilane hydrolysis and condensation are followed through infrared spectroscopy by attenuated total reflectance in order to set the coating conditions. Contact angle measurements and surface energy calculations as well as infrared and X-ray photoelectron spectroscopy are used to evaluate polymer chemical modifications. Morphological changes are studied through scanning electron and atomic force microscopy. Results show the ability of plasma treatment to create active oxydised functional groups on the polypropylene surface. These groups lead to a proper wetting of the polymer by the silane. Shear strength of single-lap bonding of polypropylene with a polyurethane adhesive suffers a significant improvement when the silane coating is applied on previously plasma activated samples. It has been also demonstrated that the silane curing conditions play a decisive role on the adhesion response. Finally, the stability of the silane solution is tested up to 30 days, yielding diminished but still acceptable adhesion strength values.

  14. Elasticity at Large Deformations and High Strain Rates in Injection Molded Polypropylene

    Dijkstra, P.T.S.; Gaymans, R.J.; Dijk, van D.J.; Huetink, J.

    2003-01-01

    The deformation behavior of isotactic polypropylene (PP) as a function of strain rate was investigated at 50°C in uniaxial tension. Injection molded dogbone specimens were tested at high strain rates, E = lo-' - 1@ s-l, and the local deformation in the neck was studied using fast tensile videometry.

  15. A Novel Approach for Observing Morphology of Polypropylene under Ultrasonic Vibration by SALS

    Li Fang TONG; Ye SHEN; Qiang ZHENG; Yong Gang SHANGGUAN

    2004-01-01

    In this paper, a set of ultrasonic vibration device connecting with small angle light scattering(SALS) for in-situ observing phase-transition of polymer under ultrasonic vibration was established. The experiments for verifying polypropylene(PP) indicated that ultrasonic vibration resulted in the decrease of the crystallization rate and made PP crystallizable at low temperature.

  16. Aluminosilicate inorganic polymers: the effects of polypropylene fillers on mechanical behavior

    Benešová, Lenka; Kotek, Jiří

    Belgrade: Materials Research Society of Serbia , 2011 - (Uskoković, D.). s. 21 [Annual Conference /13./ YUCOMAT 2011. 05.09.2011-09.09.2011, Herceg Novi] R&D Projects: GA ČR GAP108/10/1980 Institutional research plan: CEZ:AV0Z40500505 Keywords : geopolymers * mechanical behaviour * polypropylene fillers Subject RIV: JI - Composite Materials

  17. Effect of Multiple Extrusions on the Impact Properties of Polypropylene/Clay Nanocomposites

    Klitkou, Rasmus; Jensen, Erik Appel; Christiansen, Jesper de Claville

    2012-01-01

    Polypropylene (PP)-based polymer nanocomposites containing organically modified montmorillonite (OMMT) with and without maleic anhydride grafted PP, were compounded by twin-screw extrusion. The extrusion process was repeated various numbers of times to increase the extruder residence time (TR) and...

  18. Influence of hexamethylene diamine functionalized graphene oxide on the melt crystallization and properties of polypropylene nanocomposites

    Ryu, Sung Hun; Shanmugharaj, A.M., E-mail: shanmughar@gmail.com

    2014-08-01

    Hexamethylene diamine was chemically grafted to the graphene oxide (GO) surface via two type of reactions viz. (i) amidation reaction between amine groups and carboxylic acid sites of GO and (ii) nucleophilic substitution reactions between amine and epoxy groups on surface. Successful grafting of HMDA on GO surface was confirmed using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and thermogravimetric results (TGA). These chemically modified GO (AGO) with varying loading amount were incorporated in polypropylene matrix in the presence of maleic anhydride-g-polypropylene (PP-g-MA) compatibilizer through melt processing technique. X-ray diffraction (XRD) and differential scanning calorimetric (DSC) studies revealed that the loading of AGO resulted in the improvement in crystallization characteristics of polypropylene. Owing to the strong interfacial interactions between AGO and polymer, significant enhancement in mechanical and electrical properties was observed, when compared to pristine GO filled polypropylene composites. - Highlights: • Hexamethylene diamine (HMDA) was chemically grafted to graphene oxide (GO) surface. • Grafting of amine was corroborated using standard characterization tools. • Improvement in properties were observed on loading modified GO in PP nanocomposites. • Grafting of HMDA in GO resulted in strong interfacial interactions in PP matrix.

  19. BEHAVIOR OF CHO CELLS ON MODIFIED POLYPROPYLENE BY LOW TEMPERATURE AMMONIA PLASMA

    ZHANG Hong; YU Yaoting; PAN Jilun; XU Yuanping; ZHU Hesun

    2001-01-01

    The surface of polypropylene (PP) membrane was modified by low temperature plasma with ammonia. The effect of exposure time was investigated by means of contact angle measurement. The results show that low temperature ammonia plcsma treatment can enhance its hydrophilicity. Chinese hamster ovary (CHO) cells attachment on the modified membrane was enhanced and the growth rate on the membrane was faster than unmodified one.

  20. "Nara" knot for suturing of cleft lip in children to make removal easy

    Obaidullah

    2006-01-01

    Full Text Available Cleft patients usually go through a lifetime of repeated hospital admissions and multiple procedures. Suture removal at a tender age and on a sensitive area like the lip becomes a challenge for the nursing staff. It is also emotionally demanding on the part of the parents. Hence, in most centres these patients are at least sedated if not anaesthetised. We have been using a simple knot and running prolene material so that undoing of the knot becomes easy and suture removal more or less atraumatic. We would like to share our experience with readers through this article. An analysis of 53 cleft lip repairs has shown that this knot is safe and easily removable.